BDNF mediated TrkB activation is a survival signal for transitional cell carcinoma cells
ABSTRACT Pathologically, >90% of bladder cancer is transitional cell carcinoma (TCC). Previously, brain-derived neurotrophic factor (BDNF) but not tropomyosin-related kinase B (TrkB) was found in normal urothelium. TrkB activation by BDNF has been shown to promote the progression of several cancers, however, the existence and functional roles of both BDNF and TrkB in TCC have not been elucidated. In this study, three human TCC cell lines, BFTC905, TSGH8301, and T24 were used for the investigation. Both BDNF and TrkB but not TrkA or TrkC identified by RT-PCR and Western blotting were found in these cell lines. Immunostaining demonstrated the cytosolic expression of BDNF and TrkB, as well as membranous expression of TrkB in these cells. BDNF released from three cell lines was also detected in culture medium by ELISA. The proliferation of BFTC905 cells was enhanced by recombinant human BDNF (rhBDNF) in vitro, which was associated with increased phospho-TrkB and phospho-ERK levels. In contrast, TrkB-Fc chimeric protein served as BDNF scavenger eliciting cytotoxicity. Addition of rhBDNF in these cell lines cultured in poly-HEMA [Poly(2-hydroxyethyl methacrylate)] coated dishes for 48 h did not confer resistance to anoikis. Increased phospho-Akt expression was observed transiently within an hour after rhBDNF administration but disappeared 24 h later. Weekly injections of 100 ng rhBDNF into the cancer cell-loading site for 6 weeks promoted BFTC905 xenograft growth in SCID mice. Daily injection of 5 microg TrkB-Fc chimeric protein into the tumor 2 weeks after tumor cell implantation delayed tumor growth concomitant with phospho-TrkB suppression in xenografts. These results indicate that BDNF binding to TrkB receptor is a survival signal for TCC cells. Drugs that block BDNF or TrkB may provide a new and potential approach for TCC therapy.
- SourceAvailable from: Yavuz Dodurga[Show abstract] [Hide abstract]
ABSTRACT: This study was undertaken to evaluate the expression of DMBT1 in bladder cancer and its correlation with clinico-pathological parameters analyzed in bladder carcinoma patients. We investigated DMBT1 in 56 paraffin embedded specimens of transitional cell carcinoma of the urinary bladder. We assessed DMBT1 gene expression at mRNA level by RT-PCR. Our results show 100% expression of DMBT1 in bladder carcinoma samples. Due to this preliminary results; gene expression was compared to tumor grade, and a significant difference was detected between grade 1 and 3 (p = 0.028). The down-regulation of DMBT1 gene expression in carcinomas suggests the possible role in bladder cancer.Biomarkers 11/2011; 16(7):610-5. DOI:10.3109/1354750X.2011.620627 · 2.52 Impact Factor
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ABSTRACT: Pediatric glioblastoma is a malignant disease with an extremely poor clinical outcome. Patients usually suffer from resistance to radiation therapy, so targeted drug treatment may be a new possibility for glioblastoma therapy. Survivin is also overexpressed in glioblastoma. YM155, a novel small-molecule survivin inhibitor, has not been examined for its use in glioblastoma therapy. The human glioblastoma cell line M059K, which expresses normal DNA-dependent protein kinase (DNA-PK) activity and is radiation-resistant, and M059J, which is deficient in DNA-PK activity and radiation-sensitive, were used in the study. Cell viability, DNA fragmentation, and the expression of survivin and securin following YM155 treatment were examined using MTT (methylthiazolyldiphenyl-tetrazolium) assay, ELISA assay, and Western blot analysis, respectively. YM155 caused a concentration-dependent cytotoxic effect, inhibiting the cell viability of both M059K and M059J cells by 70% after 48 hours of treatment with 50 nM YM155. The half-maximal inhibitory concentration (IC50) was around 30-35 nM for both cell lines. Apoptosis was determined to have occurred in both cell lines because immunoreactive signals from the DNA fragments in the cytoplasm were increased 24 hours after treatment with 30 nM YM155. The expression of survivin and securin in the M059K cells was greater than that measured in the M059J cells. Treatment with 30 nM YM155, for both 24 and 48 hours, significantly suppressed the expression of survivin and securin in both cell lines. The novel survivin inhibitor YM155 elicits potent cytotoxicity in glioblastoma cells in vitro via DNA-PK-independent mechanisms. YM155 could be used as a new therapeutic agent for the treatment of human glioblastomas.Pediatrics & Neonatology 06/2012; 53(3):199-204. DOI:10.1016/j.pedneo.2012.04.008 · 0.88 Impact Factor
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ABSTRACT: High expression levels of TrkB and BDNF are associated with aggressive malignant behavior in tumor cells and a poor prognosis in patients with various types of cancer. In this study, we aimed to identify the relationship between TrkB and BDNF expression and clinicopathological variables and prognosis in non-small cell lung cancer (NSCLC). We evaluated TrkB and BDNF expression in the tumor cells of 102 NSCLC patients by immunohistochemistry. Out of all clinicopathological factors examined, only vascular invasion was significantly correlated with TrkB (P=0.010) and BDNF (P=0.015) expression. TrkB-positive tumors had significantly worse disease-free survival (P=0.0094) and overall survival (P=0.0019) than TrkB-negative tumors, and TrkB expression was an independent prognostic factor for disease-free survival (HR 3.735, 95%C.I. 1.560-11.068, P=0.002) and overall survival (HR 4.335, 95%C.I. 1.534-15.963, P=0.004) in multivariate analysis. Finally, our analysis revealed that co-expression of TrkB and BDNF conferred poorer prognosis compared with overexpression of either protein alone. Our results indicate that expression of TrkB and BDNF is associated with poor prognosis in NSCLC patients.Lung cancer (Amsterdam, Netherlands) 08/2012; 78(1):100-6. DOI:10.1016/j.lungcan.2012.07.011 · 3.74 Impact Factor