Combined cimetidine and temozolomide, compared with temozolomide alone: significant increases in survival in nude mice bearing U373 human glioblastoma multiforme orthotopic xenografts

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Object. Malignant gliomas consist of both heterogeneous proliferating and migrating cell subpopulations, with migrating glioma cells exhibiting less sensitivity to antiproliferative or proapoptotic drugs than proliferative cells. Therefore, the authors combined cimetidine, an antiinflammatory agent already proven to act against migrating epithelial cancer cells, with temozolomide to determine whether the combination induces antitumor activities in experimental orthotopic human gliomas compared with the effects of temozolomide alone.

Methods. Cimetidine added to temozolomide compared with temozolomide alone induced survival benefits in nude mice with U373 human glioblastoma multiforme (GBM) cells orthotopically xenografted in the brain. Computer-assisted phase-contrast microscopy analyses of 9L rat and U373 human GBM cells showed that cimetidine significantly decreased the migration levels of these tumor cells in vitro at concentrations at which tumor growth levels were not modified (as revealed on monotetrazolium colorimetric assay). Computer-assisted microscope analyses of neoglycoconjugate-based glycohistochemical staining profiles of 9L gliosarcomas grown in vivo revealed that cimetidine significantly decreased expression levels of endogenous receptors for fucose and, to a lesser extent, for N-acetyl-lactosamine moieties. Endogenous receptors of this specificity are known to play important roles in adhesion and migration processes of brain tumor cells.

Conclusions. Cimetidine, acting as an antiadhesive and therefore an antimigratory agent for glioma cells, could be added in complement to the cytotoxic temozolomide compound to combat both migrating and proliferating cells in GBM.

Abstract

Object. Malignant gliomas consist of both heterogeneous proliferating and migrating cell subpopulations, with migrating glioma cells exhibiting less sensitivity to antiproliferative or proapoptotic drugs than proliferative cells. Therefore, the authors combined cimetidine, an antiinflammatory agent already proven to act against migrating epithelial cancer cells, with temozolomide to determine whether the combination induces antitumor activities in experimental orthotopic human gliomas compared with the effects of temozolomide alone.

Methods. Cimetidine added to temozolomide compared with temozolomide alone induced survival benefits in nude mice with U373 human glioblastoma multiforme (GBM) cells orthotopically xenografted in the brain. Computer-assisted phase-contrast microscopy analyses of 9L rat and U373 human GBM cells showed that cimetidine significantly decreased the migration levels of these tumor cells in vitro at concentrations at which tumor growth levels were not modified (as revealed on monotetrazolium colorimetric assay). Computer-assisted microscope analyses of neoglycoconjugate-based glycohistochemical staining profiles of 9L gliosarcomas grown in vivo revealed that cimetidine significantly decreased expression levels of endogenous receptors for fucose and, to a lesser extent, for N-acetyl-lactosamine moieties. Endogenous receptors of this specificity are known to play important roles in adhesion and migration processes of brain tumor cells.

Conclusions. Cimetidine, acting as an antiadhesive and therefore an antimigratory agent for glioma cells, could be added in complement to the cytotoxic temozolomide compound to combat both migrating and proliferating cells in GBM.

High-grade gliomas are the most frequently encountered primary malignant neoplasms in adults.8,28 Standard treatment for these malignant gliomas is surgery, followed by radiotherapy, chemotherapy,6,15,33,36 and even more sophisticated therapies (bioreactors, neural stem cells, immunotherapies, biodegradable polymers, convection-enhanced drug delivery, and so forth).17 Note, however, that only malignant gliomas exhibiting LOH of chromosomes 1p and 19q are chemoresponsive.5,9 Unfortunately, gliomas with 1p and 19q LOH are mainly malignant oligodendrogliomas, that is, a minor proportion of malignant gliomas.28,42 Astrocytic tumors consist of a core mass and a penumbra of invasive single cells, decreasing in number toward the periphery and still detectable several centimeters away from the core lesion.3,20,24 Cell migration consists of very complex cellular and molecular processes in which at least three independent, but highly coordinated, biological steps are involved: 1) cell adhesion to specific components of the ECM;19,23,43 2) modifications in the actin cytoskeleton organization;10,34,46 and 3) secretion of proteases.47 Gene-expression profiling has already revealed numerous genes implicated in glioma cell migration, many of which relate to cell adhesion molecules that directly interact with specific ECM components.32,37,50,53 Gladson22 detailed the molecular nature of ECM in gliomas and, as she emphasized, Rutka and colleagues51,52 were among the first to recognize the importance of the ECM in the brain and in astrocytic tumors. We have shown that interactions between oligosaccharide moieties in glioma ECM and cell adhesion molecules on the surface of glioma cells exert major effects in glioma cell migration.10–13 Among these oligosaccharides are fucose and lactose.10–12,22,56

As a complement to conventional chemotherapy, anti-inflammatory compounds have been used successfully to combat cancer cell migration of epithelial origin (carcinoma) toward the liver.30,39 Metastases of epithelial cancers into the liver involve cancer cell—mediated oligosaccharide (fucose) interactions with cell adhesion molecules (selectins) present in liver microvasculatures.30,39,55 Given that the levels of expression of fucose binding activities in malignant gliomas differ in relation to the levels of malignancy12 and that these receptor types could influence the proliferation levels of human glioma cells,13 we wondered whether adding cimetidine to temozolomide treatment could improve survival periods in immunodeficient mice bearing U373 human GBM orthotopic xenografts, compared with temozolomide treatment alone. We chose the U373 GBM for our study because the lesion has an astrocytic origin without 1p and 19q LOH and is weakly sensitive to temozolomide.7 In addition, we showed that galectins (which are endogenous receptors for LacNAc moieties)—at least galectin-1—have major roles in glioma cell migration.10,11 Galectin-1 gene promoter exhibits binding sites for transcription factors activated by glucocorticoids,21 and budesonide (an antiinflammatory agent) modifies eosinophil migration features by modifying galectin-1 expression.16 Because we observed in the present study that cimetidine added to temozolomide improved survival in nude mice bearing U373 orthotopic xenografts, we analyzed whether cimetidine significantly modified in vitro growth compared with migration features of U373 human GBM and 9L rat gliosarcoma cells. We then determined whether cimetidine significantly modified expression levels of mannose-, fucose-, and LacNAc-related receptors in 9L rat gliosarcomas implanted orthotopically into the rat brains. We chose this 9L sarcoma for our study because of its diffuse invasive nature into the brain parenchyma.35

Materials and Methods

All in vivo experiments were performed with the authorization of the Animal Ethics Committee of the Faculty of Medicine of the Université Libre de Bruxelles.

Cells, Compounds, and Media

The U373 human glioma and the 9L rat gliosarcoma cells were obtained from the American Type Culture Collection (Manassas, VA). The cells were maintained as monolayers, as detailed elsewhere.34,35 Cimetidine was obtained from GSK (Genval, Belgium). Temozolomide was obtained from Schering-Plough (Kenil-worth, NJ).

Determining In Vitro Global Growth of U373 Human GBM and 9L Rat Gliosarcoma Cells

As detailed elsewhere,35 9L and U373 cell growth was assessed using the modified colorimetric MTT assay (Sigma, St. Louis, MO). The 9L and U373 cells were incubated for 72 hours in culture medium supplemented without (control) or with 10−10, 10−9, 10−8, 10−7, 10−6, 10−5, or 10−4 M cimetidine. Each experiment was performed in sextuplicate.

Determining In Vitro Migration Levels of U373 Human GBM and 9L Rat Gliosarcoma Cells

The 9L and U373 cell migration levels were characterized using a device that enables the trajectories of living cells maintained in culture to be quantified.10,11,16,34 The greatest linear distance migrated by each cell was calculated from these trajectories. This distance refers to the MRDO quantitative variable.10,11,16,34 All experiments were performed over 48 hours and one image was recorded every 4 minutes. A minimum of 314 and a maximum of 607 cells were analyzed in each experimental condition, as the analyses were performed in triplicate; that is, each experiment was repeated three times independently. The influence of cimetidine on 9L and U373 cell migration levels was analyzed at 10−8, 10−7, and 10−6 M.

In Vivo Survival Analyses in Nude Mice Bearing U373 Human GBM Orthotopic Xenografts

Orthotopic xenografts of U373 human GBM cells were obtained by grafting 106 U373 cells into the left temporal lobes of 40 8-weekold female nu/nu mice weighing 21 to 23 g (Iffa Credo; Charles River Laboratories, L'Arbresle, France). Morphological illustrations of the in vivo growth and invasion patterns of the U373 glioma cells are featured elsewhere.35

Four groups of 10 nude mice were established 10 days after orthotopic implantation of the tumor cells into the mice brains. The first group of 10 mice represented the control group and received nine intravenous (tail vein, three times a week for 3 consecutive weeks) and 30 intraperitoneal (five times a week for 6 consecutive weeks) injections of 0.2 ml saline, with the first injection administered on the 14th day post—tumor grafting. A second group received nine intravenous injections (same schedules as those for the control group) of 40 mg/kg temozolomide. This 40-mg/kg dose corresponds to one quarter of the maximal tolerated dose given in single intravenous administrations.7 Twelve intravenous administrations of 40 mg/kg temozolomide represent the maximal tolerated dose of this compound when given as 12 chronic intravenous administrations (data not shown). The third group of mice received 30 intraperitoneal administrations (five times a week for 6 consecutive weeks) of 30 mg/kg cimetidine. The fourth group received nine intravenous injections of 40 mg/kg temozolomide and 30 intraperitoneal administrations of 30 mg/kg cimetidine. Survival analyses were performed for each group.

Setting up In Vivo 9L Gliosarcomas to Characterize Cimetidine-Induced Effects on the Expression Levels of Endogenous Ligands for Mannose-, Fucose-, and Lactose-Related Moieties

Twenty male Fischer 344F rats (Charles River Laboratories) weighing 200 to 240 g received 40,000 9L cells by stereotactic procedures.35 Two groups of 10 9L gliosarcoma—grafted rats were established 2 days after implantation of the tumor cells in the rat brains. The first group of rats received 15 intraperitoneal administrations of saline (control group), that is, five times a week (Monday–Friday) for 3 consecutive weeks, with the first dose delivered on the 3rd day post—tumor grafting. The second group of rats received 15 intraperitoneal doses of 30 mg/kg cimetidine. All the rats were killed (CO2-saturated atmosphere) on the 19th day post—tumor grafting, that is, 24 hours after the last intraperitoneal injection. We administered 15 injections only because 9L tumor—bearing rats died between the 20th and 23rd day post—tumor grafting (data not shown). The rat brains were removed and fixed in buffered formalin for 2 weeks before beginning glycohistochemical analyses.

Identification of Endogenous Receptors for Mannose-, Fucose-, and Lactose-Related Moieties

The endogenous binding sites for mannose, fucose, and lactose in 9L gliosarcomas treated with cimetidine or saline (controls) were identified in formalin-fixed, paraffin-embedded tumors by using three distinct biotinylated neoglycoconjugates, that is, BSA covalently conjugated to mannose (BSA-man), fucose (BSA-fuc), and LacNAc (BSA-LacNAc).12 Incubation with or without (the latter for negative controls for computer-assisted microscopy) neoglycoconjugates was performed at 25 ± 1°C for 30 minutes in a 10-µg/ml dilution for each probe. The extent of the specifically bound biotinylated probes was demonstrated using avidin-biotin-peroxidase complex kit reagents (Vector Labs, Burlingame, CA), with diaminobenzidine and H2O2 as the chromogenic substrates. Two control experiments were performed for each of the three marker substances: 1) the omission of the incubation step with the specific neoglycoprotein to be analyzed; and 2) the incubation of the labeled probe in the presence of a 200-fold excess amount of the corresponding mono- or disaccharide. These control reactions enabled sugar specificity to be ascertained for each carrier-immobilized oligosaccharide, as described previously.12 Omission of the incubation step with a labeled marker served to exclude any staining by the binding of kit reagents such as the mannose-rich glycoprotein horseradish peroxidase and avidin. Counterstaining with hematoxylin concluded the processing.

Computer-assisted microscopy was used to determine quantitatively the expression levels of endogenous ligands for the mannose-, fucose-, and LacNAc-related oligosaccharide moieties. Two variables were computed for each of the three biotinylated neoglycoconjugate-related stainings by using a computer-assisted microscope system (SAMBA 2005; UNILOG, Grenoble, France) with a 20× (aperture 0.50) magnification lens. The labeling index refers to the percentage of tissue area specifically stained by a histochemical probe. The mean optical density denotes the staining intensity. The way in which we used the computer-assisted system to quantify the histochemical staining has been detailed previously.11,12 The software used on the computer-assisted microscope automatically subtracted the labeling index and mean optical density values of the negative control sample from each corresponding positive one. Special software programs were run on the computer assisting the microscope to check any inherent shading, glare, and the level of linearity precision in the CCD camera-based systems. Shading and glare were checked every week. The monitoring program installed on the computer-assisted microscope showed that shading, glare, or linearity did not significantly modify our results (data not shown). All slides relating to a given histochemical probe were stained together to minimize reproducibility problems.

After processing with each of the three glycohistochemical markers, 20 areas of between 60,000 and 120,000 µm2 were scanned on each of the four histological slides for each of the 20 9L gliosarcomas under study. A computer mouse linked to the software on the computer-assisted microscope enabled analysis of the invading islets of tumor cells separately from the tumor core.

Statisical Analysis

Statistical comparisons of the different groups were made by first performing the Kruskal—Wallis test (a nonparametric one-way analysis of variance). When this test revealed some significant differences, we compared pairs of groups by applying the Dunn procedure (two-sided test) for multiple comparisons. The rank correlation test involved the nonparametric Kendall test. All statistical analyses were performed using Statistica (Statsoft, Tulsa, OK). A value less than 0.05 was defined as statistically significant.

Results
Effects of Combined Temozolomide and Cimetidine on Survival in Nude Mice Bearing U373 Human GBM Orthotopic Xenografts

The weights of the U373 xenograft—bearing nude mice were recorded to monitor potential toxic side effects of the various treatments applied in the present study. The three treatments—temozolomide alone, cimetidine alone, and the combination of temozolomide and cimetidine—were well tolerated by the U373 xenograft—bearing mice as they did not lose significant weight compared with the control animals (data not shown). Cimetidine or temozolomide alone induced no statistically significant increase in survival (Fig. 1). In contrast, the combined treatment of temozolomide and cimetidine significantly increased survival. Indeed, five of the nine U373 GBM—bearing mice that benefited from this combined treatment died after the last control mouse.

Fig. 1.
Fig. 1.

Graph demonstrating the influence of temozolomide (nine intravenous 40-mg/kg injections administered three times a week for 3 consecutive weeks), cimetidine (30 intraperitoneal 30-mg/kg injections administered five times a week for 6 consecutive weeks), and their combination (nine intravenous injections of 40 mg/kg temozolomide and 30 intraperitoneal injections of 30 mg/kg cimetidine), compared with the control condition, on the survival of nude mice orthotopically xenografted with 106 human GBM cells in the brain on Day 0. Treatment started on Day 14 post—tumor grafting.

In Vitro Cimetidine-Mediated Effects on the Global Growth Pattern of 9L Rat Gliosarcoma and U373 Human GBM Cell Lines

We determined whether the survival benefit added by cimetidine in the combined treatment (cimetidine and temozolomide) of U373 xenograft—bearing nude mice (Fig. 1) could relate to a cimetidine-induced decrease in the global growth rates of the GBM cells. Results of in vitro colorimetric MTT-based assays revealed that cimetidine significantly decreased the growth rates of both U373 GBM and 9L gliosarcoma cells at concentrations equal to, or higher than, 100 µM (data not shown). These concentrations were not compatible with the effects observed in vivo, which occurred at significantly lower doses. Thus, we investigated whether cimetidine was able to modify the migration levels of both U373 and 9L tumor cells, as detailed later.

In Vitro Cimetidine-Mediated Effects on the Migration Levels of 9L Rat Gliosarcoma and U373 Human GBM Cell Lines

Figure 2A illustrates the migration pattern of U373 human GBM cells during a 24-hour observation period. One image was digitized every 4 minutes during this 24-hour period, and a sequence of 360 digitized images was compiled into a movie that lasted up to 20 seconds. The software that we developed allowed us to digitize each cell, and thereafter the digitized image of the cell was reduced to its center of gravity. The centers of gravity of each cell that had been recorded every 4 minutes for a maximum of 24 hours were then linked together, each color line in Fig. 2B indicating the trajectory followed by each U373 cell. Data revealed that certain cells traveled rather linearly in the CCD camera-related field of observation, whereas others moved at random near their initial position. We recorded the MRDO (quantitative variable expressed in micrometers/hour) to characterize the migration level of each cell (Fig. 2C). Given that our data (Fig. 2A–C) clearly indicated that in vitro tumor cell populations—at least the U373 human GBM and 9L rat gliosarcoma cell lines (data not shown)—exhibit dramatically pronounced features of cell heterogeneity when cell proliferation and cell migration are considered together, we analyzed the influence of cimetidine on migrating cells. Therefore, on the one hand, we determined the effects of cimetidine on the entire population of U373 and 9L cells, that is, 100% of the cells that were tracked using the CCD camera (Fig. 2E and G); these tumor cell populations included proliferating as well as migrating cells (Fig. 2A and B). On the other hand, we analyzed pure migrating tumor cell populations, that is, 25% of the most motile tumor cells (Fig. 2D) among the entire tumor cell population analyzed (Fig. 2F and H).

Fig. 2.
Fig. 2.

Characterization of the influence of cimetidine on the migration levels of U373 human GBM and 9L rat gliosarcoma cells. A: A computer-assisted phase-contrast microscopy image demonstrating the migration pattern of a U373 GBM cell population. One image was obtained every 4 minutes during a period of 24 hours. Original magnification × 100. B: Image obtained using software we developed, demonstrating the distance traveled by each individual cell during a 24-hour observation period. C: Illustration depicting representative tumor cells (black oval) reduced to their center of gravity. All centers of gravity for a given cell were recorded during a 24-hour period and linked together to show the cell's trajectory. Tumor cell c1 did not migrate; that is, the beginning (b1) of its trajectory was nearly superposed on the end (e1) of its trajectory. In contrast, cell c2 did migrate; the beginning (b2) of its trajectory was far away from the end (e2) of its trajectory. D: Graph exhibiting the distribution of MRDO values in a control U373 tumor cell population, with a subpopulation of 25% of the most motile cells represented on the right side of the graph (arrow). Bar graphs of 100% of the GBM cells analyzed (E) and the 25% most motile GBM cells analyzed (F), indicating the influence of 10 (open bar), 100 (gray bar), and 1000 nM (black bar) cimetidine over time (12–48 hours after its addition to the culture media) on migration levels (MRDO variable). Bar graphs demonstrating the migration levels of 100% of the gliosarcoma cells analyzed (G) and 25% of the most motile gliosarcoma cells analyzed (H).

The levels of U373 GBM (Fig. 2E and F) and 9L gliosarcoma (Fig. 2G and H) cell migration in control conditions—that is, the cells not treated with cimetidine—were arbitrarily normalized at 0% of the MRDO values. The horizontal rectangle (p > 0.05) in each graph in Fig. 2E to H indicates that modifications between −10 and 10% of the MRDO values approximating the 0% control value are not statistically significant. Modifications of MRDO values between ×10 and ×20% compared with the 0% control value are weak but statistically significant (p < 0.05). The modifications in MRDO values below −20% compared with the 0% control value are statistically significant (p < 0.01).

The addition of 10 nM cimetidine did not significantly modify migration levels of GBM and gliosarcoma cells (Fig. 2E and G, respectively), compared with the control condition. In contrast, 100 and 1000 nM cimetidine significantly decreased the migration levels of both GBM and gliosarcoma cells 36 hours after adding the agent to the culture medium. These effects were much more marked in 25% of the most motile (Fig. 2D) GBM (Fig. 2F) and gliosarcoma (Fig. 2H) cell subpopulations.

Influence of Cimetidine on Glycohistochemical Expression Levels of Mannose-, Fucose-, and LacNAc-Specified Endogenous Receptors in 9L Gliosarcoma Cells Grown In Vivo in Rat Brains

We separately analyzed the expression levels of endogenous mannose-, fucose-, and LacNAc-related receptors, exposing neoglycoproteins in the core (C in Fig. 3A) of gliosarcomas as opposed to islets (II in Fig. 3A) of 9L cells invading the brain parenchyma. Note that the 9L gliosarcoma is highly invasive through the brain parenchyma; it exhibits high proliferation indices and is well vascularized (Fig. 3B). Given that we observed no statistically distinct expression levels of the binding sites for the three glycohistochemical markers in these two histological compartments (data not shown), we pooled the data together for the sake of clarity (Fig. 3C and D).

Fig. 3.
Fig. 3.

Photomicrographs depicting the dramatically invasive (thus migrating) nature of 9L rat gliosarcoma cells into the brain parenchyma (A) and their proliferating capacities (B). C = core of tumor; II = invading islets of tumor cells. C: Bar graph demonstrating the percentages of 9L tumor cells exhibiting endogenous receptors for mannose (open bar), fucose (gray bar), and LacNAc (black bar) moieties without (control) or with cimetidine treatment (30 intraperitoneal administrations of 30 mg/kg five times per week for 6 consecutive weeks) in rats. D: Bar graph exhibiting the 9L tumor cell density for the three types of endogenous receptors, which were glycohistochemically detected by neoglycoconjugates carrying mannose (E) and LacNAc (F) ligands in control 9L gliosarcomas, and fucose ligands in a control (G) and a cimetidine-treated (H) 9L gliosarcoma. H & E (A and B), original magnifications × 100 (A), × 400 (B and E–H).

Cimetidine did not significantly modify the percentage of 9L tumor cells exhibiting endogenous ligands for mannoserelated oligosaccharide moieties (Fig. 3C), whereas it weakly, but significantly, decreased the concentration of endogenous ligands for mannose-related oligosaccharide moieties in 9L tumor cells (Fig. 3D). Figure 3E illustrates the glycohistochemical pattern of mannose-specific endogenous receptors in a control 9L gliosarcoma.

Cimetidine markedly decreased the percentage of 9L tumor cells exhibiting endogenous receptors for fucose moieties (Fig. 3C); it also significantly decreased the concentration of endogenous receptors for fucose moieties in 9L tumor cells (Fig. 3D). Figure 3G and H illustrate the glycohistochemical pattern of receptors for fucose in a control and in a cimetidine-treated 9L gliosarcoma, respectively.

Cimetidine weakly, but significantly, decreased the percentage of 9L tumor cells exhibiting endogenous receptors for LacNAc moieties (Fig. 3C), whereas it did not significantly modify the density of endogenous receptors for LacNAc moieties in 9L tumor cells (Fig. 3D). Figure 3F illustrates the glycohistochemical pattern of LacNAc-specific endogenous receptors in a control 9L gliosarcoma.

Discussion

Malignant gliomas are biologically heterogeneous and include subpopulations of proliferating and migrating cells.17,20,28 Although certain intracellular signaling pathways specifically control cell proliferation and/or apoptosis, other intracellular signaling pathways control cell migration.3,20,29,45 For example, CAS/Crk assembly serves as a molecular switch for the induction of cell migration and appears to contribute to the invasive property of tumors.29 Because of the presence of distinct subpopulations of proliferating and migrating cells in malignant gliomas, adjuvant chemotherapy currently used to combat proliferating glioma cells is weakly, if at all, effective against migrating glioma cells. There is also accumulating evidence that invasive glioma cells show a decreased proliferation rate and a relative resistance to apoptosis, which may contribute to chemotherapy and radiotherapy resistance.8,20,29,45 Therefore, it should be interesting to elaborate new therapeutic strategies aiming to combat migrating glioma cells. One major target in the fight against glioma cell migration relates to the successful decrease in protease expression by glioma cells.47 Another major target concerns adhesion molecules and their ligands in the ECM. By example, tenascin, an integrin ligand, is overexpressed in the ECM of malignant gliomas compared with its expression in low-grade gliomas or normal brain parenchyma,22 and clinical applications are undertaken specifically to combat this particular feature of glioma cell migration.48

Apart from integrins,22,26,44 galectins10–12 also exert crucial roles in glioma cell migration. Whereas integrins use protein—protein interactions with ECM components, galectins use protein—carbohydrate interactions between themselves and ECM glycoproteins. Note that the core of carbohydrate ligands for galectins are represented by LacNAc moieties. With respect to the metastatic process of epithelial cells colonizing the liver, the interactions between a third group of adhesion molecules, that is, selectins, and their fucosyl-related LacNAc ligands (Lewis antigens) also play crucial roles.27,39,55 In fact, epithelial cells detaching from primary epithelial tumors (carcinomas) and migrating through the lymphatic system or the blood vessels eventually colonize the liver given the fact that cancerous epithelial cells exhibiting Lewis antigens on their surface are able to adhere to endothelial cells in liver sinusoids, because of the presence of selectins (the ligands for Lewis antigens) in these liver endothelial cells.25,27,39,55 On entry in the hepatic circulation, epithelial tumor cells can rapidly trigger a molecular cascade (involving interleukin-1 secretion by tumor cells), leading to the induction of E-selectin expression on the sinusoidal endothelium.25,27 Cimetidine is a histamine receptor-type H2 blocker and its use in clinics has already been proven to be beneficial in patients with colon cancer30,39 because it antagonizes tumor cell—mediated interleukin-1—induced activation of selectins in liver sinusoids,30,39 therefore reducing the binding capacities of tumor cells on liver sinusoids. Furthermore, in some cases, histamine is able to act as a growth factor through the activation of H2 receptors,18 and cimetidine has already been shown to be capable of reducing in vitro or in vivo growth rates of a large panel of human cancers, including nontumorous cells of colon origin1 as well as melanomas49 and gliomas.18 In the present study, we showed that cimetidine-mediated effects on U373 human GBM and 9L rat gliosarcoma cell growth occurred at concentrations of approximately 100 µM, whereas such effects on migration levels of these tumor cells occurred at approximately or below µM ranges of doses. Thus, the in vivo benefit demonstrated by the addition of cimetidine to temozolomide with respect to the survival periods in mice bearing U373 human GBM orthotopic xenografts, compared with temozolomide alone (Fig. 1), refers to decreases in cell migration capacities rather than in cell growing capacities. We observed in vitro that cimetidine induced no modification in either cell cycle kinetics or apoptotic features with the use of doses between 100 and 0.1 µM (data not shown).

The CD15 epitope (fucosyl-LacNAc) is present on almost all types of carcinoma cells (gastric, pancreatic, colon, breast, and so forth) and even on normal astrocytes, whereas it is absent on glioma cells.38 Martin and colleagues38 asserted that the absence of CD15 on human glioma cells may explain, to some extent, the general failure of intrinsic brain gliomas to metastasize by precluding the adhesion of circulating glioma cells to target organ endothelium. Although CD15 is absent from glioma cells, other fucosyl-related oligosaccharide moieties have very important roles in glioma cell biology. Indeed, fucose-containing glycoproteins have been suspected as candidates for the tumor suppressor function in GBM cells.54 Berezovskaya, et al.,4 observed an upregulation of fucose residues on the cell membranes of C6 glioma cells when the tumor cells were submitted to starvation, that is, a dramatic decrease in serum concentration. We monitored the expression of glycan-binding sites on a panel of 10 biotinylated neoglycoconjugates in 108 human astrocytic tumors, and clear differences were observed between nondiffuse (pilocytic) and diffuse (astrocytic) tumors, including distinct levels of fucose-related oligosaccharide moieties.12

Analysis of data from the present study showed that cimetidine markedly decreased both the percentage of 9L rat gliosarcoma cells with endogenous receptors for fucose moieties and the 9L tumor cell density for such receptors. We observed similar features with the U373 cells in a preliminary experiment (data not shown). This cimetidine-mediated decrease in endogenous receptors for fucose moieties could, at least partially, explain the cimetidine-induced decrease in 9L (and U373) tumor cell migration and the in vivo benefit of adding cimetidine to temozolomide (Fig. 1).

Fucose-containing glycans with potential clinical applications are hypothesized to combat the development of malignant gliomas. Indeed, it has been known for a long time that the astrocyte number is constant in the mammalian central nervous system during adulthood and old age in normal circumstances because of the balance of division promoters and division inhibitors.31 Nieto-Sampedro40 identified the mitogen inhibitors as immunologically related to blood group oligosaccharides (that is, Lewis antigen—related structures) and to glycan epitopes of the epidermal growth factor receptor. On the basis of these data, Aguilera, et al.,2 synthesized a family of oligosaccharides with a common Lewis X-type structure (that is, fucosyl-LacNAc—related structures), and these compounds exerted significant antiproliferative activity against malignant GBM cells.41

Data in the present study also revealed that cimetidine slightly, but significantly, decreases the expression levels of endogenous receptors for LacNAc moieties. Such endogenous ligands definitely involve distinct types of galectins including, for example, galectin-1, whose expression levels can be modulated by antiinflammatory compounds.14,16,21 We clearly demonstrated the role played by galectin-1 on glioma cell migration features.10,11 Thus, the cimetidine-induced decrease in endogenous ligands for LacNAc (maybe galectin-1) can synergistically act with the cimetidine-induced decrease in endogenous receptors for fucose on both 9L and U373 tumor cell migration levels (Fig. 2) and, in turn, on the in vivo benefit contributed by adding cimetidine to temozolomide (Fig. 1). We observed that Medrol induced no effect on galectin expression in U373 and 9L tumors (data not shown).

Conclusions

In summary, analysis of data in the present study showed that adding cimetidine, an antiinflammatory agent acting as a histamine H2 receptor antagonist, to temozolomide contributes a survival benefit compared with the use of temozolomide alone in nude mice bearing U373 human GBM orthotopic xenografts. This beneficial effect could relate to a cimetidine-induced decrease in GBM cell migration capacities, a decrease probably linked to cimetidine-induced modifications in the expression levels of endogenous receptors for fucosyl- and LacNAc-containing oligosaccharide moieties.

References

  • 1.

    Adams WJLawson JAMorris DL: Cimetidine inhibits in vivo growth of human colon cancer and reverses histamine stimulated in vitro and in vivo growth. Gut 35:163216361994Gut 35:

  • 2.

    Aguilera BRomero-Ramirez LAbad-Rodriguez JCorrales GNieto-Sampedro MFernandez-Mayoralas A: Novel disaccharide inhibitors of human glioma cell division. J Med Chem 41:459946061998J Med Chem 41:

  • 3.

    Beliën ATPaganetti PASchwab ME: Membrane-type 1 matrix metalloprotease (MT1-MMP) enables invasive migration of glioma cells in central nervous system white matter. J Cell Biol 144:3733841999J Cell Biol 144:

  • 4.

    Berezovskaya OLMares VSkibo GG: Growth related changes in sugar determinants on the surface of C6 glioma cells in culture: a cytochemical lectin-binding study. J Neurosci Res 42:1921981995J Neurosci Res 42:

  • 5.

    Bigner SHMatthews MRRasheed BKAWiltshire RNFriedman HSFriedman AHet al: Molecular genetic aspects of oligodendrogliomas including analysis by comparative genomic hybridization. Am J Pathol 155:3753861999Am J Pathol 155:

  • 6.

    Brandes AA: State-of-the-art treatment of high-grade brain tumors. Semin Oncol 30 (Suppl 19):492003Brandes AA: State-of-the-art treatment of high-grade brain tumors. Semin Oncol 30 (Suppl 19):

  • 7.

    Branle FLefranc FCamby IJeuken JGeurts-Moespot ASprenger Set al: Evaluation of the efficiency of chemotherapy in in vivo orthotopic models of human glioma cells with and without 1p19q deletions and in C6 rat orthotopic allografts serving for the evaluation of surgery combined with chemotherapy. Cancer 95:6416552002Cancer 95:

  • 8.

    Burton ECPrados MD: Malignant gliomas. Curr Treat Options Oncol 1:4594682000Curr Treat Options Oncol 1:

  • 9.

    Cairncross JGUeki KZlatescu MCLisle DKFinkelstein DMHammond RRet al: Specific genetic predictors of chemotherapeutic response and survival in patients with anaplastic oligodendrogliomas. J Natl Cancer Inst 90:147314791998J Natl Cancer Inst 90:

  • 10.

    Camby IBelot NLefranc FSadeghi Nde Launoit YKaltner Het al: Galectin-1 modulates human glioblastoma cell migration into the brain through modifications to the actin cytoskeleton and levels of expression of small GTPases. J Neuropathol Exp Neurol 61:5855962002J Neuropathol Exp Neurol 61:

  • 11.

    Camby IBelot NRorive SLefranc FMaurage CALahm Het al: Galectins are differentially expressed in supratentorial pilocytic astrocytomas, astrocytomas, anaplastic astrocytomas and glioblastomas, and significantly modulate tumor astrocyte migration. Brain Pathol 11:12262001Brain Pathol 11:

  • 12.

    Camby IDecaestecker CGordower LDeDecker RKacem YLemmers Aet al: Distinct differences in binding capacity to saccharide epitopes in supratentorial pilocytic astrocytomas, astrocytomas, anaplastic astrocytomas, and glioblastomas. J Neuropathol Exp Neurol 60:75842001J Neuropathol Exp Neurol 60:

  • 13.

    Camby ISalmon IDe Decker RPasteels JLBrotchi JDanguy Aet al: Lectin histochemistry of astrocytic tumors and in vitro characterization of lectin-induced modifications on the proliferation of the SW1088, U373 and U87 human astrocytic cell lines. J Neurooncol 34:1111221997J Neurooncol 34:

  • 14.

    Chiariotti LSalvatore PFrunzio RBruni CB: Galectin genes: regulation of expression. Glycoconj J 19:4414492004Glycoconj J 19:

  • 15.

    DeAngelis LM: Benefits of adjuvant chemotherapy in high-grade gliomas. Semin Oncol 30 (Suppl 19):15182003DeAngelis LM: Benefits of adjuvant chemotherapy in high-grade gliomas. Semin Oncol 30 (Suppl 19):

  • 16.

    Delbrouck CDoyen IBelot NDecaestecker CGhanooni Rde Lavareille Aet al: Galectin-1 is overexpressed in nasal polyps under budesonide and inhibits eosinophil migration. Lab Invest 82:1471582002Lab Invest 82:

  • 17.

    Dunn IFBlack PM: The neurosurgeon as local oncologist: cellular and molecular neurosurgery in malignant glioma therapy. Neurosurgery 52:141114242003Neurosurgery 52:

  • 18.

    Finn PEPurnell PPilkington GJ: Effect of histamine and the H2 antagonist cimetidine on the growth and migration of human neoplastic glia. Neuropathol Appl Neurobiol 22:3173241996Neuropathol Appl Neurobiol 22:

  • 19.

    Giancotti FGRuoslahti E: Integrin signaling. Science 285:102810321999Science 285:

  • 20.

    Giese ABjerkvig RBerens MEWestphal M: Cost of migration: invasion of malignant gliomas and implications for treatment. J Clin Oncol 21:162416362003J Clin Oncol 21:

  • 21.

    Gitt MABarondes SH: Genomic sequence and organization of two members of a human lectin gene family. Biochemistry 30:82891991Biochemistry 30:

  • 22.

    Gladson CL: The extracellular matrix of gliomas: modulation of cell function. J Neuropathol Exp Neurol 58:102910401999Gladson CL: The extracellular matrix of gliomas: modulation of cell function. J Neuropathol Exp Neurol 58:

  • 23.

    Hood JDCheresh DA: Role of integrins in cell invasion and migration. Nat Rev Cancer 2:911002002Nat Rev Cancer 2:

  • 24.

    Jung SAckerley CIvanchuk SMondal SBecker LERutka JT: Tracking the invasiveness of human astrocytoma cells by using green fluorescent protein in an organotypical brain slice model. J Neurosurg 94:80892001J Neurosurg 94:

  • 25.

    Kaji MIshikura HKishimoto TOmi MIshizu AKimura Cet al: E-selectin expression induced by pancreas-carcinoma-derived interleukin-1 alpha results in enhanced adhesion of pancreas-carcinoma cells to endothelial cells. Int J Cancer 60:7127171995Int J Cancer 60:

  • 26.

    Kanamori MVanden Berg SRBergers GBerger MSPieper RO: Integrin β3 overexpression suppresses tumor growth in a human model of gliomagenesis: implications for the role of β3 overexpression in glioblastoma multiforme. Cancer Res 64:275127582004Cancer Res 64:

  • 27.

    Khatib AMKontogiannea MFallavollita LJamison BMeterissian SBrodt P: Rapid induction of cytokine and E-selectin expression in the liver in response to metastatic tumor cells. Cancer Res 59:135613611999Cancer Res 59:

  • 28.

    Kleihues PCavenee WK: Pathology and Genetics of Tumours of the Nervous System. Lyon: IARC Press2000Pathology and Genetics of Tumours of the Nervous System.

  • 29.

    Klemke RLLeng JMolander RBrooks PCVuori KCheresh DA: CAS/Crk coupling serves as a “molecular switch” for induction of cell migration. J Cell Biol 140:9619721998J Cell Biol 140:

  • 30.

    Kobayashi KIMatsumoto SMorishima TKawabe TOkamoto T: Cimetidine inhibits cancer cell adhesion to endothelial cells and prevents metastasis by blocking E-selectin expression. Cancer Res 60:397839842000Cancer Res 60:

  • 31.

    Korr H: Proliferation and cell cycle parameters of astrocytesFedoroff SVernadakis A (eds): Astrocytes Cell Biology and Pathology of Astrocytes. London: Academic Press198677127Astrocytes Cell Biology and Pathology of Astrocytes.

  • 32.

    Kucharczak JPannequin JCamby IDecaestecker CKiss RMartinez J: Gastrin induces over-expression of genes involved in human U373 glioblastoma cell migration. Oncogene 20:702170282001Oncogene 20:

  • 33.

    Laws ERParney IFHuang WAnderson FMorris AMAsher Aet al: Survival following surgery and prognostic factors for recently diagnosed malignant glioma: data from the Glioma Outcomes Project. J Neurosurg 99:4674732003J Neurosurg 99:

  • 34.

    Lefranc FCamby IBelot NBruyneel EChaboteaux CBrotchi Jet al: Gastrin significantly modifies the migratory abilities of experimental glioma cells. Lab Invest 82:124112522002Lab Invest 82:

  • 35.

    Lefranc FSadeghi NMetens TBrotchi JSalmon IKiss R: Characterization of gastrin-induced cytostatic effect on cell proliferation in experimental malignant gliomas. Neurosurgery 52:8818912003Neurosurgery 52:

  • 36.

    Macdonald DR: New frontiers in the treatment of malignant glioma. Semin Oncol 30 (Suppl 19):72762003Macdonald DR: New frontiers in the treatment of malignant glioma. Semin Oncol 30 (Suppl 19):

  • 37.

    Mariani LMcDonough WSHoelzinger DBBeaudry CKaczmarek ECoons SWet al: Identification and validation of P311 as a glioblastoma invasion gene using laser capture microdissection. Cancer Res 61:419041962001P311 as a glioblastoma invasion gene using laser capture microdissection. Cancer Res 61:

  • 38.

    Martin KAkinwunmi JRooprai HKKennedy AJLinke AOgnjenovic Net al: Nonexpression of CD15 by neoplastic glia: a barrier to metastasis? Anticancer Res 15:115911661995Anticancer Res 15:

  • 39.

    Matsumoto SImaeda YUmemoto SKobayashi KSuzuki HOkamoto T: Cimetidine increases survival of colorectal cancer patients with high levels of sialyl Lewis-X and sialyl Lewis-A epitope expression on tumour cells. Br J Cancer 86:1611672002Br J Cancer 86:

  • 40.

    Nieto-Sampedro M: Astrocyte mitogen inhibitor related to epidermal growth factor receptor. Science 240:178417861988Nieto-Sampedro M: Astrocyte mitogen inhibitor related to epidermal growth factor receptor. Science 240:

  • 41.

    Nieto-Sampedro MBailon CFernandez-Mayoralas AMartin-Lomas MMellstrom BNaranjo JR: Experimental brain glioma: growth arrest and destruction by a blood-group-related tetrasaccharide. J Neuropathol Exp Neurol 55:1691771996J Neuropathol Exp Neurol 55:

  • 42.

    Nutt CLMani DRBetensky RATamayo PCairncross JGLadd Cet al: Gene expression-based classification of malignant gliomas correlates better with survival than histological classification. Cancer Res 63:160216072003Cancer Res 63:

  • 43.

    Palecek SPLoftus JCGinsberg MHLauffenburger DAHorwitz AF: Integrin-ligand binding properties govern cell migration speed through cell-substratum adhesiveness. Nature 385:5375401997Nature 385:

  • 44.

    Paulus WBaur ISchuppan DRoggendorf W: Characterization of integrin receptors in normal and neoplastic human brain. Am J Pathol 143:1541631993Am J Pathol 143:

  • 45.

    Puchner MJAGiese A: Tamoxifen-resistant glioma-cell sub-populations are characterized by increased migration and proliferation. Int J Cancer 86:4684732000Int J Cancer 86:

  • 46.

    Raftopoulou MHall A: Cell migration: Rho GTPases lead the way. Dev Biol 265:23322004Dev Biol 265:

  • 47.

    Rao JS: Molecular mechanisms of glioma invasiveness: the role of proteases. Nat Rev Cancer 3:4895012003Rao JS: Molecular mechanisms of glioma invasiveness: the role of proteases. Nat Rev Cancer 3:

  • 48.

    Reardon DAAkabani GColeman REFriedman AHFriedman HSHerndon JE IIet al: Phase II trial of murine 131I-labeled antitenascin monoclonal antibody 81C6 administered into surgically created resection cavities of patients with newly diagnosed malignant gliomas. J Clin Oncol 20:138913972002131I-labeled antitenascin monoclonal antibody 81C6 administered into surgically created resection cavities of patients with newly diagnosed malignant gliomas. J Clin Oncol 20:

  • 49.

    Reynolds JLAkhter JMorris DL: In vitro effect of histamine and histamine H1 and H2 receptor antagonists on cellular proliferation of human malignant melanoma cell lines. Melanoma Res 6:95991996Melanoma Res 6:

  • 50.

    Rickman DSBobek MPMisek DEKuick RBlaivas MKurnit DMet al: Distinctive molecular profiles of high-grade and low-grade gliomas based on oligonucleotide microarray analysis. Cancer Res 61:688568912001Cancer Res 61:

  • 51.

    Rutka JTApodaca GStern RRosenblum M: The extracellular matrix of the central and peripheral nervous systems: structure and function. J Neurosurg 69:1551701988J Neurosurg 69:

  • 52.

    Rutka JTMyatt CAGiblin JRDavis RLRosenblum ML: Distribution of extracellular matrix proteins in primary human brain tumours: an immunohistochemical analysis. Can J Neurol Sci 14:25301987Can J Neurol Sci 14:

  • 53.

    Tatenhorst LSenner VPuttmann SPaulus W: Regulators of G-protein signaling 3 and 4 (RGS3, RGS4) are associated with glioma cell motility. J Neuropathol Exp Neurol 63:2102222004J Neuropathol Exp Neurol 63:

  • 54.

    VanderMeulen DLPrasad VVMoskal JR: The identification of glioblastoma-associated, fucose-containing glycoproteins induced by retinoic acid. Mol Chem Neuropathol 21:3113271994Mol Chem Neuropathol 21:

  • 55.

    Weston BWHiller KMMayben JPManousos GABendt KMLiu Ret al: Expression of human α(1,3)fucosyltransferase antisense sequences inhibits selectin-mediated adhesion and liver metastasis of colon carcinoma cells. Cancer Res 59:212721351999Cancer Res 59:

  • 56.

    Yates AJComas TScheithauer BWBurger PCPearl DK: Glycolipid markers of astrocytomas and oligodendrogliomas. J Neuropathol Exp Neurol 58:125012621999J Neuropathol Exp Neurol 58:

The present study was funded by grants awarded by the Région de Bruxelles-Capitale (Brussels, Belgium) and the Fondation Yvonne Boël (Brussels, Belgium).

Article Information

Address reprint requests to: Robert Kiss, Ph.D., Laboratory of Toxicology, Institute of Pharmacy, Université Libre de Bruxelles, Campus de la Plaine, Boulevard du Triomphe, 1050 Brussels, Belgium. email: rkiss@ulb.ac.be.

© AANS, except where prohibited by US copyright law.

Headings

Figures

  • View in gallery

    Graph demonstrating the influence of temozolomide (nine intravenous 40-mg/kg injections administered three times a week for 3 consecutive weeks), cimetidine (30 intraperitoneal 30-mg/kg injections administered five times a week for 6 consecutive weeks), and their combination (nine intravenous injections of 40 mg/kg temozolomide and 30 intraperitoneal injections of 30 mg/kg cimetidine), compared with the control condition, on the survival of nude mice orthotopically xenografted with 106 human GBM cells in the brain on Day 0. Treatment started on Day 14 post—tumor grafting.

  • View in gallery

    Characterization of the influence of cimetidine on the migration levels of U373 human GBM and 9L rat gliosarcoma cells. A: A computer-assisted phase-contrast microscopy image demonstrating the migration pattern of a U373 GBM cell population. One image was obtained every 4 minutes during a period of 24 hours. Original magnification × 100. B: Image obtained using software we developed, demonstrating the distance traveled by each individual cell during a 24-hour observation period. C: Illustration depicting representative tumor cells (black oval) reduced to their center of gravity. All centers of gravity for a given cell were recorded during a 24-hour period and linked together to show the cell's trajectory. Tumor cell c1 did not migrate; that is, the beginning (b1) of its trajectory was nearly superposed on the end (e1) of its trajectory. In contrast, cell c2 did migrate; the beginning (b2) of its trajectory was far away from the end (e2) of its trajectory. D: Graph exhibiting the distribution of MRDO values in a control U373 tumor cell population, with a subpopulation of 25% of the most motile cells represented on the right side of the graph (arrow). Bar graphs of 100% of the GBM cells analyzed (E) and the 25% most motile GBM cells analyzed (F), indicating the influence of 10 (open bar), 100 (gray bar), and 1000 nM (black bar) cimetidine over time (12–48 hours after its addition to the culture media) on migration levels (MRDO variable). Bar graphs demonstrating the migration levels of 100% of the gliosarcoma cells analyzed (G) and 25% of the most motile gliosarcoma cells analyzed (H).

  • View in gallery

    Photomicrographs depicting the dramatically invasive (thus migrating) nature of 9L rat gliosarcoma cells into the brain parenchyma (A) and their proliferating capacities (B). C = core of tumor; II = invading islets of tumor cells. C: Bar graph demonstrating the percentages of 9L tumor cells exhibiting endogenous receptors for mannose (open bar), fucose (gray bar), and LacNAc (black bar) moieties without (control) or with cimetidine treatment (30 intraperitoneal administrations of 30 mg/kg five times per week for 6 consecutive weeks) in rats. D: Bar graph exhibiting the 9L tumor cell density for the three types of endogenous receptors, which were glycohistochemically detected by neoglycoconjugates carrying mannose (E) and LacNAc (F) ligands in control 9L gliosarcomas, and fucose ligands in a control (G) and a cimetidine-treated (H) 9L gliosarcoma. H & E (A and B), original magnifications × 100 (A), × 400 (B and E–H).

References

1.

Adams WJLawson JAMorris DL: Cimetidine inhibits in vivo growth of human colon cancer and reverses histamine stimulated in vitro and in vivo growth. Gut 35:163216361994Gut 35:

2.

Aguilera BRomero-Ramirez LAbad-Rodriguez JCorrales GNieto-Sampedro MFernandez-Mayoralas A: Novel disaccharide inhibitors of human glioma cell division. J Med Chem 41:459946061998J Med Chem 41:

3.

Beliën ATPaganetti PASchwab ME: Membrane-type 1 matrix metalloprotease (MT1-MMP) enables invasive migration of glioma cells in central nervous system white matter. J Cell Biol 144:3733841999J Cell Biol 144:

4.

Berezovskaya OLMares VSkibo GG: Growth related changes in sugar determinants on the surface of C6 glioma cells in culture: a cytochemical lectin-binding study. J Neurosci Res 42:1921981995J Neurosci Res 42:

5.

Bigner SHMatthews MRRasheed BKAWiltshire RNFriedman HSFriedman AHet al: Molecular genetic aspects of oligodendrogliomas including analysis by comparative genomic hybridization. Am J Pathol 155:3753861999Am J Pathol 155:

6.

Brandes AA: State-of-the-art treatment of high-grade brain tumors. Semin Oncol 30 (Suppl 19):492003Brandes AA: State-of-the-art treatment of high-grade brain tumors. Semin Oncol 30 (Suppl 19):

7.

Branle FLefranc FCamby IJeuken JGeurts-Moespot ASprenger Set al: Evaluation of the efficiency of chemotherapy in in vivo orthotopic models of human glioma cells with and without 1p19q deletions and in C6 rat orthotopic allografts serving for the evaluation of surgery combined with chemotherapy. Cancer 95:6416552002Cancer 95:

8.

Burton ECPrados MD: Malignant gliomas. Curr Treat Options Oncol 1:4594682000Curr Treat Options Oncol 1:

9.

Cairncross JGUeki KZlatescu MCLisle DKFinkelstein DMHammond RRet al: Specific genetic predictors of chemotherapeutic response and survival in patients with anaplastic oligodendrogliomas. J Natl Cancer Inst 90:147314791998J Natl Cancer Inst 90:

10.

Camby IBelot NLefranc FSadeghi Nde Launoit YKaltner Het al: Galectin-1 modulates human glioblastoma cell migration into the brain through modifications to the actin cytoskeleton and levels of expression of small GTPases. J Neuropathol Exp Neurol 61:5855962002J Neuropathol Exp Neurol 61:

11.

Camby IBelot NRorive SLefranc FMaurage CALahm Het al: Galectins are differentially expressed in supratentorial pilocytic astrocytomas, astrocytomas, anaplastic astrocytomas and glioblastomas, and significantly modulate tumor astrocyte migration. Brain Pathol 11:12262001Brain Pathol 11:

12.

Camby IDecaestecker CGordower LDeDecker RKacem YLemmers Aet al: Distinct differences in binding capacity to saccharide epitopes in supratentorial pilocytic astrocytomas, astrocytomas, anaplastic astrocytomas, and glioblastomas. J Neuropathol Exp Neurol 60:75842001J Neuropathol Exp Neurol 60:

13.

Camby ISalmon IDe Decker RPasteels JLBrotchi JDanguy Aet al: Lectin histochemistry of astrocytic tumors and in vitro characterization of lectin-induced modifications on the proliferation of the SW1088, U373 and U87 human astrocytic cell lines. J Neurooncol 34:1111221997J Neurooncol 34:

14.

Chiariotti LSalvatore PFrunzio RBruni CB: Galectin genes: regulation of expression. Glycoconj J 19:4414492004Glycoconj J 19:

15.

DeAngelis LM: Benefits of adjuvant chemotherapy in high-grade gliomas. Semin Oncol 30 (Suppl 19):15182003DeAngelis LM: Benefits of adjuvant chemotherapy in high-grade gliomas. Semin Oncol 30 (Suppl 19):

16.

Delbrouck CDoyen IBelot NDecaestecker CGhanooni Rde Lavareille Aet al: Galectin-1 is overexpressed in nasal polyps under budesonide and inhibits eosinophil migration. Lab Invest 82:1471582002Lab Invest 82:

17.

Dunn IFBlack PM: The neurosurgeon as local oncologist: cellular and molecular neurosurgery in malignant glioma therapy. Neurosurgery 52:141114242003Neurosurgery 52:

18.

Finn PEPurnell PPilkington GJ: Effect of histamine and the H2 antagonist cimetidine on the growth and migration of human neoplastic glia. Neuropathol Appl Neurobiol 22:3173241996Neuropathol Appl Neurobiol 22:

19.

Giancotti FGRuoslahti E: Integrin signaling. Science 285:102810321999Science 285:

20.

Giese ABjerkvig RBerens MEWestphal M: Cost of migration: invasion of malignant gliomas and implications for treatment. J Clin Oncol 21:162416362003J Clin Oncol 21:

21.

Gitt MABarondes SH: Genomic sequence and organization of two members of a human lectin gene family. Biochemistry 30:82891991Biochemistry 30:

22.

Gladson CL: The extracellular matrix of gliomas: modulation of cell function. J Neuropathol Exp Neurol 58:102910401999Gladson CL: The extracellular matrix of gliomas: modulation of cell function. J Neuropathol Exp Neurol 58:

23.

Hood JDCheresh DA: Role of integrins in cell invasion and migration. Nat Rev Cancer 2:911002002Nat Rev Cancer 2:

24.

Jung SAckerley CIvanchuk SMondal SBecker LERutka JT: Tracking the invasiveness of human astrocytoma cells by using green fluorescent protein in an organotypical brain slice model. J Neurosurg 94:80892001J Neurosurg 94:

25.

Kaji MIshikura HKishimoto TOmi MIshizu AKimura Cet al: E-selectin expression induced by pancreas-carcinoma-derived interleukin-1 alpha results in enhanced adhesion of pancreas-carcinoma cells to endothelial cells. Int J Cancer 60:7127171995Int J Cancer 60:

26.

Kanamori MVanden Berg SRBergers GBerger MSPieper RO: Integrin β3 overexpression suppresses tumor growth in a human model of gliomagenesis: implications for the role of β3 overexpression in glioblastoma multiforme. Cancer Res 64:275127582004Cancer Res 64:

27.

Khatib AMKontogiannea MFallavollita LJamison BMeterissian SBrodt P: Rapid induction of cytokine and E-selectin expression in the liver in response to metastatic tumor cells. Cancer Res 59:135613611999Cancer Res 59:

28.

Kleihues PCavenee WK: Pathology and Genetics of Tumours of the Nervous System. Lyon: IARC Press2000Pathology and Genetics of Tumours of the Nervous System.

29.

Klemke RLLeng JMolander RBrooks PCVuori KCheresh DA: CAS/Crk coupling serves as a “molecular switch” for induction of cell migration. J Cell Biol 140:9619721998J Cell Biol 140:

30.

Kobayashi KIMatsumoto SMorishima TKawabe TOkamoto T: Cimetidine inhibits cancer cell adhesion to endothelial cells and prevents metastasis by blocking E-selectin expression. Cancer Res 60:397839842000Cancer Res 60:

31.

Korr H: Proliferation and cell cycle parameters of astrocytesFedoroff SVernadakis A (eds): Astrocytes Cell Biology and Pathology of Astrocytes. London: Academic Press198677127Astrocytes Cell Biology and Pathology of Astrocytes.

32.

Kucharczak JPannequin JCamby IDecaestecker CKiss RMartinez J: Gastrin induces over-expression of genes involved in human U373 glioblastoma cell migration. Oncogene 20:702170282001Oncogene 20:

33.

Laws ERParney IFHuang WAnderson FMorris AMAsher Aet al: Survival following surgery and prognostic factors for recently diagnosed malignant glioma: data from the Glioma Outcomes Project. J Neurosurg 99:4674732003J Neurosurg 99:

34.

Lefranc FCamby IBelot NBruyneel EChaboteaux CBrotchi Jet al: Gastrin significantly modifies the migratory abilities of experimental glioma cells. Lab Invest 82:124112522002Lab Invest 82:

35.

Lefranc FSadeghi NMetens TBrotchi JSalmon IKiss R: Characterization of gastrin-induced cytostatic effect on cell proliferation in experimental malignant gliomas. Neurosurgery 52:8818912003Neurosurgery 52:

36.

Macdonald DR: New frontiers in the treatment of malignant glioma. Semin Oncol 30 (Suppl 19):72762003Macdonald DR: New frontiers in the treatment of malignant glioma. Semin Oncol 30 (Suppl 19):

37.

Mariani LMcDonough WSHoelzinger DBBeaudry CKaczmarek ECoons SWet al: Identification and validation of P311 as a glioblastoma invasion gene using laser capture microdissection. Cancer Res 61:419041962001P311 as a glioblastoma invasion gene using laser capture microdissection. Cancer Res 61:

38.

Martin KAkinwunmi JRooprai HKKennedy AJLinke AOgnjenovic Net al: Nonexpression of CD15 by neoplastic glia: a barrier to metastasis? Anticancer Res 15:115911661995Anticancer Res 15:

39.

Matsumoto SImaeda YUmemoto SKobayashi KSuzuki HOkamoto T: Cimetidine increases survival of colorectal cancer patients with high levels of sialyl Lewis-X and sialyl Lewis-A epitope expression on tumour cells. Br J Cancer 86:1611672002Br J Cancer 86:

40.

Nieto-Sampedro M: Astrocyte mitogen inhibitor related to epidermal growth factor receptor. Science 240:178417861988Nieto-Sampedro M: Astrocyte mitogen inhibitor related to epidermal growth factor receptor. Science 240:

41.

Nieto-Sampedro MBailon CFernandez-Mayoralas AMartin-Lomas MMellstrom BNaranjo JR: Experimental brain glioma: growth arrest and destruction by a blood-group-related tetrasaccharide. J Neuropathol Exp Neurol 55:1691771996J Neuropathol Exp Neurol 55:

42.

Nutt CLMani DRBetensky RATamayo PCairncross JGLadd Cet al: Gene expression-based classification of malignant gliomas correlates better with survival than histological classification. Cancer Res 63:160216072003Cancer Res 63:

43.

Palecek SPLoftus JCGinsberg MHLauffenburger DAHorwitz AF: Integrin-ligand binding properties govern cell migration speed through cell-substratum adhesiveness. Nature 385:5375401997Nature 385:

44.

Paulus WBaur ISchuppan DRoggendorf W: Characterization of integrin receptors in normal and neoplastic human brain. Am J Pathol 143:1541631993Am J Pathol 143:

45.

Puchner MJAGiese A: Tamoxifen-resistant glioma-cell sub-populations are characterized by increased migration and proliferation. Int J Cancer 86:4684732000Int J Cancer 86:

46.

Raftopoulou MHall A: Cell migration: Rho GTPases lead the way. Dev Biol 265:23322004Dev Biol 265:

47.

Rao JS: Molecular mechanisms of glioma invasiveness: the role of proteases. Nat Rev Cancer 3:4895012003Rao JS: Molecular mechanisms of glioma invasiveness: the role of proteases. Nat Rev Cancer 3:

48.

Reardon DAAkabani GColeman REFriedman AHFriedman HSHerndon JE IIet al: Phase II trial of murine 131I-labeled antitenascin monoclonal antibody 81C6 administered into surgically created resection cavities of patients with newly diagnosed malignant gliomas. J Clin Oncol 20:138913972002131I-labeled antitenascin monoclonal antibody 81C6 administered into surgically created resection cavities of patients with newly diagnosed malignant gliomas. J Clin Oncol 20:

49.

Reynolds JLAkhter JMorris DL: In vitro effect of histamine and histamine H1 and H2 receptor antagonists on cellular proliferation of human malignant melanoma cell lines. Melanoma Res 6:95991996Melanoma Res 6:

50.

Rickman DSBobek MPMisek DEKuick RBlaivas MKurnit DMet al: Distinctive molecular profiles of high-grade and low-grade gliomas based on oligonucleotide microarray analysis. Cancer Res 61:688568912001Cancer Res 61:

51.

Rutka JTApodaca GStern RRosenblum M: The extracellular matrix of the central and peripheral nervous systems: structure and function. J Neurosurg 69:1551701988J Neurosurg 69:

52.

Rutka JTMyatt CAGiblin JRDavis RLRosenblum ML: Distribution of extracellular matrix proteins in primary human brain tumours: an immunohistochemical analysis. Can J Neurol Sci 14:25301987Can J Neurol Sci 14:

53.

Tatenhorst LSenner VPuttmann SPaulus W: Regulators of G-protein signaling 3 and 4 (RGS3, RGS4) are associated with glioma cell motility. J Neuropathol Exp Neurol 63:2102222004J Neuropathol Exp Neurol 63:

54.

VanderMeulen DLPrasad VVMoskal JR: The identification of glioblastoma-associated, fucose-containing glycoproteins induced by retinoic acid. Mol Chem Neuropathol 21:3113271994Mol Chem Neuropathol 21:

55.

Weston BWHiller KMMayben JPManousos GABendt KMLiu Ret al: Expression of human α(1,3)fucosyltransferase antisense sequences inhibits selectin-mediated adhesion and liver metastasis of colon carcinoma cells. Cancer Res 59:212721351999Cancer Res 59:

56.

Yates AJComas TScheithauer BWBurger PCPearl DK: Glycolipid markers of astrocytomas and oligodendrogliomas. J Neuropathol Exp Neurol 58:125012621999J Neuropathol Exp Neurol 58:

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