stilbenes and Medulloblastoma

Medulloblastoma (MB) is the most common pediatric brain tumor. Current treatment regimes consisting of primary surgery followed by radio- and chemotherapy, achieve 5-year overall survival rates of only about 60 %. Therapy-induced endocrine and neurocognitive deficits are common late adverse effects. Thus, improved antitumor strategies are urgently needed. In this study, we combined irradiation (IR) together with epigenetic modifiers and differentiation inducers in a multimodal approach to enhance the efficiency of tumor therapy in MB and also assessed possible late adverse effects on neurogenesis.. In three human MB cell lines (DAOY, MEB-Med8a, D283-Med) short-time survival (trypan blue exclusion assay), apoptosis, autophagy, cell cycle distribution, formation of gH2AX foci, and long-term reproductive survival (clonogenic assay) were analyzed after treatment with 5-aza-2'-deoxycytidine (5-azadC), valproic acid (VPA), suberanilohydroxamic acid (SAHA), abacavir (ABC), all-trans retinoic acid (ATRA) and resveratrol (RES) alone or combined with 5-aza-dC and/or IR. Effects of combinatorial treatments on neurogenesis were evaluated in cultured murine hippocampal slices from transgenic nestin-CFPnuc C57BL/J6 mice. Life imaging of nestin-positive neural stem cells was conducted at distinct time points for up to 28 days after treatment start.. All tested drugs showed a radiosynergistic action on overall clonogenic survival at least in two-outof-three MB cell lines. This effect was pronounced in multimodal treatments combining IR, 5-aza-dC and a second drug. Hereby, ABC and RES induced the strongest reduction of clongenic survival in all three MB cell lines and led to the induction of apoptosis (RES, ABC) and/or autophagy (ABC). Additionally, 5-aza-dC, RES, and ABC increased the S phase cell fraction and induced the formation of gH2AX foci at least in oneout-of-three cell lines. Thereby, the multimodal treatment with 5-aza-dC, IR, and RES or ABC did not change the number of normal neural progenitor cells in murine slice cultures.. In conclusion, the radiosensitizing capacities of epigenetic and differentiation-inducing drugs presented here suggest that their adjuvant administration might improve MB therapy. Thereby, the combination of 5-aza-dC/IR with ABC and RES seemed to be the most promising to enhance tumor control without affecting the normal neural precursor cells.

Topics: Animals; Antineoplastic Agents; Antineoplastic Combined Chemotherapy Protocols; Azacitidine; Cell Differentiation; Cell Line, Tumor; Cell Proliferation; Cell Survival; Cerebellar Neoplasms; Combined Modality Therapy; Decitabine; Dideoxynucleosides; Epigenesis, Genetic; Humans; Hydroxamic Acids; Medulloblastoma; Mice; Neurogenesis; Radiation-Sensitizing Agents; Resveratrol; Stilbenes; Treatment Outcome; Tretinoin; Valproic Acid; Vorinostat; Xenograft Model Antitumor Assays

Activated STAT3 signaling is critical for human medulloblastoma cells. SHP2, SOCS3 and PIAS3 are known as the negative regulators of STAT3 signaling, while their relevance to frequent STAT3 activation in medulloblastomas remains unknown.. Tissue microarrays were constructed with 17 tumor-surrounding noncancerous brain tissues and 61 cases of the classic medulloblastomas, 44 the large-cell medulloblastomas, and 15 nodular medulloblastomas, which were used for immunohistochemical profiling of STAT3, SHP2, SOCS3 and PIAS3 expression patterns and the frequencies of STAT3 nuclear translocation. Three human medulloblastoma cell lines (Daoy, UW228-2 and UW228-3) were cultured with and without 100 μM resveratrol supplementation. The influences of resveratrol in SHP2, SOCS3 and PIAS3 expression and SOCS3 knockdown in STAT3 activation were analyzed using multiple experimental approaches.. SHP2, SOCS3 and PIAS3 levels are reduced in medulloblastomas in vivo and in vitro, of which PIAS3 downregulation is more reversely correlated with STAT3 activation. In resveratrol-suppressed medulloblastoma cells with STAT3 downregulation and decreased incidence of STAT3 nuclear translocation, PIAS3 is upregulated, the SHP2 level remains unchanged and SOCS3 is downregulated. SOCS3 proteins are accumulated in the distal ends of axon-like processes of resveratrol-differentiated medulloblastoma cells. Knockdown of SOCS3 expression by siRNA neither influences cell proliferation nor STAT3 activation or resveratrol sensitivity but inhibits resveratrol-induced axon-like process formation.. Our results suggest that (1) the overall reduction of SHP2, SOCS3 and PIAS3 in medulloblastoma tissues and cell lines; (2) the more inverse relevance of PIAS3 expression with STAT3 activation; (3) the favorable prognostic values of PIAS3 for medulloblastomas and (4) the involvement of SOCS3 in resveratrol-promoted axon regeneration of medulloblastoma cells.

Topics: Cell Differentiation; Cell Line, Tumor; Cell Proliferation; Down-Regulation; Gene Expression Regulation, Neoplastic; Gene Knockdown Techniques; Humans; Medulloblastoma; Molecular Chaperones; Protein Inhibitors of Activated STAT; Resveratrol; Signal Transduction; STAT3 Transcription Factor; Stilbenes; Suppressor of Cytokine Signaling 3 Protein

Resveratrol promotes differentiation and apoptosis of medulloblastoma cells by suppressing STAT3 signaling and a range of cancer-associated gene expression. However, Bcl-2, a common target of STAT3 and NF-κB signaling, is distinctly up-regulated in resveratrol-treated medulloblastoma cells, indicating potential effects of NF-κB in Bcl-2 expression and anti-medulloblastoma efficiency of resveratrol. To clarify this point, the status of NF-κB signaling and the consequence of NF-κB inhibition in UW228-2 and UW228-3 medulloblastoma cells without and with resveratrol treatment were evaluated by several experimental approaches. The results revealed that resveratrol activated NF-κB signaling in both cell lines at the 4-h treatment point, and the treated cells sequentially exhibited Bcl-2 up-regulation, neuronal-like phenotype with synaptophisin expression, and, eventually, apoptosis. Pyrrolidine dithiocarbamate (PDTC) treatment inhibited NF-κB activation and Bcl-2 expression and committed resveratrol-treated cells to apoptosis at the 8-h time point without the step of neuron-oriented differentiation. On the other hand, a single 50 μg/ml lipopolysaccharide (LPS) treatment activated NF-κB signaling accompanied with sustained proliferation and neuron-like differentiation. Tissue microarray-based immunohistochemical staining showed significantly different (P < 0.001) p65 nuclear translocation between the neurons of tumor-surrounding cerebella (10/10; 100%) and medulloblastoma tissues (20/117; 17.09%). Additionally, synaptophysin production was found in 83.64% of p65-positive and in 40.35% of p65-negative medulloblastoma cases. Our in-vitro and in-vivo results thus demonstrate the dual effects of NF-κB signaling on medulloblastoma cells by delaying resveratrol-induced apoptosis by up-regulating Bcl-2 expression or by involvement in neuronal-like differentiation in the absence of resveratrol. Therefore, appropriate inhibition of NF-κB activation may enhance the anti-medulloblastoma efficacy of resveratrol.

Topics: Anticarcinogenic Agents; Apoptosis; Cell Line, Tumor; Cerebellum; Flow Cytometry; Humans; Lipopolysaccharides; Medulloblastoma; Neurons; NF-kappa B; Proline; Protein Array Analysis; Resveratrol; Signal Transduction; STAT3 Transcription Factor; Stilbenes; Tetrazolium Salts; Thiazoles; Thiocarbamates; Time Factors

Cancer preventive reagent trans-resveratrol is intracellularly biotransformed to different metabolites. However, it is still unclear whether trans-resveratrol exerts its biological effects directly or through its metabolite(s). This issue was addressed here by identifying the metabolic pattern and the bioactive form of resveratrol in a resveratrol-sensitive human medulloblastoma cell line, UW228-3. The cell lysates and condition media of UW228-3 cells with or without 100 microM resveratrol treatment were analyzed by HPLC and LC/MS which revealed (1) that resveratrol was chemically unstable and the spontaneous generation of cis-resveratrol reduced resveratrol's anti-medulloblastoma efficacy and (2) that resveratrol monosulfate was the major metabolite of the cells. To identify the bioactive form of resveratrol, a mixture-containing approximately half fraction of resveratrol monosulfate was prepared by incubating trans-resveratrol with freshly prepared rat brain lysates. Medulloblastoma cells treated by 100 microM of this mixture showed attenuated cell crisis. The overall levels of the three brain-associated sulfotransferases (SULT1A1, 1C2 and 4A1) were low in medulloblastoma cells in vivo and in vitro in comparison with that in human noncancerous and rat normal cerebella; resveratrol could more or less up-regulate the production of these enzymes in UW228-3 cells but their overall level was still lower than that in normal cerebellum tissue. Our study thus demonstrated for the first time that trans-resveratrol is the bioactive form in medulloblastoma cells in which the expression of brain-associated SULTs was down-regulated, resulting in the increased intracellular bioavailability and anti-medulloblastoma efficacy of trans-resveratrol.

Topics: Adolescent; Animals; Antineoplastic Agents; Biotransformation; Blotting, Western; Cell Line, Tumor; Cerebellar Neoplasms; Child; Chromatography, High Pressure Liquid; Humans; Medulloblastoma; Rats; Resveratrol; Reverse Transcriptase Polymerase Chain Reaction; Stilbenes; Sulfotransferases; Young Adult

Interactions between nerve growth factor (NGF) and its receptor-the tropomyosin related kinase A (trkA)-regulate many neuronal functions including the correct development of sensory neurons during embryogenesis, the survival of sensory neurons and the differentiation and apoptosis of neuronal tumours. Zhangfei is a transcriptional factor that is expressed in differentiated neurons. Since we could detect Zhangfei in mature neurons but not in neuronal tumour cells, we hypothesised that ectopic expression of the protein in medulloblastoma cells may induce the differentiation of these cells. We show that in ONS-76 medulloblastoma cells, resveratrol, an inducer of apoptosis and differentiation, increased the expression of Zhangfei, trkA and Early Growth Response Gene 1 (Egr1), a gene normally activated by NGF-trkA signalling. ONS-76 cells stopped growing soon after treatment with resveratrol. While the induction of Zhangfei in resveratrol-treated cells was modest albeit consistent, the infection of actively growing medulloblastoma cells with an adenovirus vector expressing Zhangfei mimicked some of the effects of resveratrol. Ectopically expressed Zhangfei in ONS-76 cells led to the increased expression of trkA and Egr1, phosphorylation of extracellular signal-regulated kinase (Erk1), and caused ONS-76 cells to display markers of apoptosis. UW228, another medulloblastoma cell-line, was also susceptible to the suppressive effects of resveratrol and Zhangfei. In contrast, while resveratrol suppressed the growth of human diploid fibroblasts (MRC5), Zhangfei had relatively little effect on these cells.

Topics: Angiogenesis Inhibitors; Animals; Apoptosis; Basic-Leucine Zipper Transcription Factors; Caspase 3; Cell Differentiation; Cell Line, Tumor; Cell Proliferation; Early Growth Response Protein 1; Flow Cytometry; Gene Expression Regulation, Neoplastic; Humans; Medulloblastoma; PC12 Cells; Rats; Receptor, Nerve Growth Factor; Receptor, trkA; Resveratrol; Stilbenes; Time Factors; Transfection

Resveratrol (RV), a natural polyphenol derived from red wine, recently showed the potential of anticancer and radiosensitizing effects. A recent study has suggested that the cancer stem cells (CSCs) may reflect the clinical refractory malignancy of brain tumors, including medulloblastoma (MB). The aim of the present study is to investigate the possible role of RV in radiosensitivity of MB cells and MB-associated CSCs.. MB-associated CSCs were isolated and cultured by serum-free medium with basic fibroblast growth factor (bFGF) and epidermal growth factor (EGF). The parental MB cells and MB-CSCs were treated with RV in different concentrations and assessed for cell viability. The treatment includes RV alone, radiation alone, or radiation combined with RV.. MB-CSCs selected by serum-free medium with bFGF and EGF can form 3D spheroid formation and display enhanced self-renewal and highly co-expressed "stem cell" genes (Oct-4, Nanog, Nestin, and Musashi-1) as well as antiapoptotic genes (Bcl-2 and Bcl-xL). These MB-CSCs showed significant resistance to radiotherapy as compared to the parental MB cells. Importantly, 100 muM RV could effectively inhibit the proliferation of MB-CSCs and significantly enhance the radiosensitivity in RV-treated MB-CSCs.. Our data suggest that RV can effectively inhibit the proliferation and tumorigenicity of MB-CSCs and significantly synergistically enhance radiosensitivity in RV-treated MB-CSCs.

Topics: Anticarcinogenic Agents; bcl-2-Associated X Protein; bcl-X Protein; Cell Proliferation; Cells, Cultured; Chemotherapy, Adjuvant; Humans; Intermediate Filament Proteins; Medulloblastoma; Neoplastic Stem Cells; Nerve Tissue Proteins; Nestin; Radiotherapy, Adjuvant; Resveratrol; Reverse Transcriptase Polymerase Chain Reaction; Stilbenes

In this study, the potential influence of resveratrol (3,5,4'-trihydroxy-trans-stilbene) in signal transducer and activator of transcription 3 (STAT3) signaling of medulloblastoma cells was evaluated by checking the status of STAT3 signaling and its downstream gene expression in two medulloblastoma cell lines (UW228-2 and UW228-3) with and without resveratrol treatment. The results revealed that resveratrol induced neuronal differentiation of medulloblastoma cells. Signal transducer and activator of transcription 3 expression and phosphorylation were detected in normally cultured UW228-2 and UW228-3 cells that were apparently attenuated after resveratrol treatment. The expression of STAT3 downstream genes, survivin, cyclin D1, Cox-2, and c-Myc, was suppressed but Bcl-2 was enhanced by resveratrol. Meanwhile, the production and secretion of leukemia inhibitory factor, a STAT3 activator, became active in resveratrol-treated cells. To further ascertain the significance of STAT3 signaling for medulloblastoma cells, AG490, a selective inhibitor of STAT3 phosphorylation, was used to treat UW228-3 cells. Phosphorylation of STAT3 was inhibited by AG490 accompanied with growth suppression, differentiation-like changes, and down-regulation of survivin, cyclin D1, Cox-2, and c-Myc. Our data thus suggest the importance of STAT3 signaling in maintenance and survival of medulloblastoma cells. This signaling may be the major target of resveratrol. Enhanced leukemia inhibitory factor and Bcl-2 expressions in resveratrol-treated cells might reflect a compensatory response to the loss of STAT3 function.

Topics: Antineoplastic Agents; Cell Differentiation; Cell Survival; Cerebellar Neoplasms; Down-Regulation; Enzyme Inhibitors; Gene Expression Regulation, Neoplastic; Humans; Leukemia Inhibitory Factor; Medulloblastoma; Neurons; Resveratrol; Signal Transduction; STAT3 Transcription Factor; Stilbenes; Tumor Cells, Cultured; Tyrphostins

Altered Notch signaling seems linked with medulloblastoma (MB) formation and resveratrol exhibits anti-medulloblastoma effects. However, the influence of resveratrol in Notch signaling of MB cells has not been described. This issue was addressed here by checking Notch1 and Notch2 statuses in three MB cell lines with and without resveratrol treatment. Notch1 and Notch2 were detected in the cytoplasm of three cell lines under normal condition, which were up-regulated by resveratrol along with differentiation, apoptosis and enhanced Hes1 nuclear translocation. Nevertheless, blockage of Notch enzymatic cleavage with gamma-seacretase inhibitors, DAPT and L-685,458, neither interrupted resveratrol-caused cellular events nor affected MB cell growth. These results demonstrate that Notch signaling has little relevance with resveratrol-induced differentiation and apoptosis and may not be a universal critical factor of MB cells.

Topics: Active Transport, Cell Nucleus; Amyloid Precursor Protein Secretases; Antineoplastic Agents; Antioxidants; Apoptosis; Basic Helix-Loop-Helix Transcription Factors; Brain Neoplasms; Cell Differentiation; Cell Line, Tumor; Cell Proliferation; Cytoplasm; Enzyme Inhibitors; Homeodomain Proteins; Humans; Medulloblastoma; Receptor, Notch1; Receptor, Notch2; Receptors, Notch; Resveratrol; Signal Transduction; Stilbenes; Transcription Factor HES-1; Up-Regulation

The correlation of c-Myc expression with resveratrol-induced turnover of medulloblastoma cells was investigated in this study by checking (1) c-Myc expression in medulloblastoma tissues and cell lines (UW228-2 and UW228-3), (2) the in vitro effect of resveratrol on c-Myc expression and (3) the influences of c-Myc inhibition in cell growth and survival. Immunohistochemical staining of human medulloblastomas and noncancerous cerebellar tissues revealed that 8 out of 11 tumor tissues (72.7%) expressed c-Myc, in which 4 cases (50%) showed intensified nuclear labeling. RT-PCR, Western blotting, immunocytochemical and immunofluorescence stainings revealed c-Myc downregulation accompanied with growth suppression and apoptosis. Flow cytometry analysis showed S phase arrest in resveratrol-treated cell populations. Transfection of c-Myc directed antisense oligonucleotides to the cultured medulloblastoma cells could reduce c-Myc expression, inhibit cell growth and arrest the cell cycle at S phase. Our results thus for the first time demonstrate that c-Myc downregulation is a critical molecular event of resveratrol-mediated anti-medulloblastoma activity, which is closely associated with growth suppression, cell cycle arrest and apoptosis of medulloblastoma cells.

Topics: Antioxidants; Apoptosis; Blotting, Western; Brain Neoplasms; Cell Cycle; Cell Line, Tumor; Cell Survival; Down-Regulation; Flow Cytometry; Fluorescent Antibody Technique; Genes, myc; Humans; Immunohistochemistry; Medulloblastoma; Neoplasm Proteins; Oligonucleotides, Antisense; Resveratrol; Reverse Transcriptase Polymerase Chain Reaction; RNA, Neoplasm; S Phase; Stilbenes; Transfection

Resveratrol induces differentiation and Fas-independent apoptosis of medulloblastoma cells by a largely unknown mechanism. CYP1A1 and 1B1 are involved in resveratrol-mediated tumor suppression but their expression in medulloblastoma cells and their relevance to anti-medulloblastoma activity of resveratrol have not been described. The statuses of CYP1A1 and 1B1 in UW228-3 medulloblastoma cells without and with resveratrol treatments were elucidated in this study with ethoxyresorufin O-deethylation assay, followed by RT-PCR, immunocytochemical staining and Western blot hybridization. CYP1A1/1B1 enzymatic activity was low in UW228-3 cells but became several folds higher upon resveratrol treatments. CYP1A1 was undetectable and CYP1B1 was expressed in normally cultured cells. Accompanied by the increased fraction of apoptosis, enhanced CYP1A1 and downregulated CYP1B1 were observed in resveratrol-treated cells in time- and dose-related fashions. Our results demonstrate for the first time that in the medulloblastoma cell system, CYP1A1 upregulation is paralleled with resveratrol-induced differentiation and apoptosis, while CYP1B1 may not be an essential element in metabolic activation of resveratrol in those cells. CYP1A1 and 1B1 are resveratrol response genes and potential chemosensitive markers of medulloblastoma cells.

Topics: Antineoplastic Agents, Phytogenic; Aryl Hydrocarbon Hydroxylases; Blotting, Western; Cell Line, Tumor; Cell Survival; Cytochrome P-450 CYP1A1; Cytochrome P-450 CYP1B1; Cytochrome P-450 Enzyme System; Dose-Response Relationship, Drug; Fas Ligand Protein; fas Receptor; Flow Cytometry; Gene Expression Regulation, Enzymologic; Humans; Immunohistochemistry; Medulloblastoma; Membrane Glycoproteins; Resveratrol; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Stilbenes; Time Factors

Resveratrol has tumor-suppressive activities in some in vitro and in vivo experimental systems but its effect on medulloblastoma cells is still unknown. In this study, resveratrol was used to treat four human medulloblastoma cell lines (Med-3, UW228-1, -2 and -3) and its effects on cell growth, differentiation and death were examined by multiple approaches. Expression of Fas, FasL and caspase-3 in the cells without and with resveratrol treatments was examined by immunocytochemical staining and mRNA in situ hybridization and the influence of anti-Fas antibody (200 ng/ml) in cell growth and survival was determined as well. The results demonstrated that resveratrol could suppress growth, promote differentiation and commit its target cells to apoptosis in time- and dose-related fashions. Fas was constitutively expressed but FasL was undetectable in the four lines in spite of resveratrol treatment. Anti-Fas antibody (200 ng/ml) neither inhibited growth nor induced apoptosis of those cell lines. Up-regulated caspase-3 was found in resveratrol-treated populations and appearance of its cleaved form was closely associated with the apoptotic event. These findings suggest for the first time that resveratrol is an effective anti-medulloblastoma agent that kills medulloblastoma cells through a Fas-independent pathway.

Topics: Antineoplastic Agents, Phytogenic; Apoptosis; Caspase 3; Caspases; Cell Differentiation; Cell Division; Cell Line, Tumor; Cell Survival; Cerebellar Neoplasms; Dose-Response Relationship, Drug; Fas Ligand Protein; fas Receptor; Humans; Medulloblastoma; Membrane Glycoproteins; Resveratrol; RNA, Messenger; Stilbenes; Up-Regulation