ABSTRACT
Emerging evidence has indicated that circular RNAs (circRNAs) play pivotal roles in the regulation of cellular processes and are found to be aberrantly expressed in a variety of tumors.However,the clinical role of circRNAs in bladder cancer (BC) and the molecular mechanisms have yet to be fully understood.In this study,the clinical specimens were obtained and the expression level of a circRNA BCRC4 was detected by real-time PCR in both BC tissues and cell line.The circular RNA over-expression plasmid was constructed and transfected into BC cells and related cell line.The cell cycles and apoptosis were observed using inverted microscope and flow cytometry.Western blotting was used to compare the relative protein expression of groups with different treatments.It was found that circRNA BCRC4 expression was lower in BC tissues than in adjacent normal tissues.Furthermore,consequences of fomed-expression of BCRC4 promoted apoptosis and inhibited viability of T24T and UMUC3 cells,and up-regulated BCRC4-inereased miR-101 level,which suppressed EZH2 expression in both RNA and protein levels.In addition,gambogic acid (GA) is a promising natural anticancer compound for BC therapy,and GA treatment increased the BCRC4 expression in T24T and UMUC3 cells in a dose-dependent manner.Altogether,our findings suggest that BCRC4 functions as a tumor suppressor in BC,and mediates anticancer function,at least in part,by up-regulating the expression of miR-101.Targeting this newly identified circRNA may help us develop a novel strategy for treating human BC.
ABSTRACT
The effect of Smac gene on the TRAIL-induced apoptosis of the prostate cancer cell line PC-3 and the molecular mechanism were investigated.The Smac gene was transfected into PC-3 cells under the induction of liposome.The intrinsic Smac gene expression was detected by Western blotting.After treatment with TRAIL as an apoptosis inducer,in vitro cell growth activity was assayed by MTT colorimetry.The apoptosis rate of PC-3 cells was determined by annexin V -FITC and propidium iodide staining flow cytometry.The expression of cellular XIAP and caspase-3 genes was examined by Western blotting.Smac-transfected cells (PC-3/Smac group) had significantly increased Smac protein level as compared with PC-3 controls (P＜0.01).After induction with 100-200 ng/mL TRAIL for 12-36 h,cellular proliferation rate in PC-3/Smac group was significantly lower than in PC-3 controls (P＜0.05).After induction with 100 ng/mL TRAIL for 24 h,the apoptosis rate in PC-3/Smac group was significantly enhanced as compared with that of PC-3 controls (P＜0.05).Accordingly,the XIAP expression level was down-regulated significantly (P＜0.05) and caspase-3 subunit P20 was up-regulated significantly (P＜0.05).It is suggested that the over-expression of cellular Smac can inhibit inhibitor of apoptosis proteins (IAPs),enhance caspases activity and the apoptosis rate of PC-3 cells induced by TRAIL,which may provide a useful experimental basis for prostate cancer therapy.
ABSTRACT
The effects of synthetic Smac peptide (SmacN7) on chemotherapeutic sensitivity of bladder cancer cells were investigated. SmacN7 penetratin peptide was synthesized and delivered into T24 cells. MTT assay was used to evaluate the viability of T24 cells induced by low-dosage of MMC. Flow cytometry was used to analyze the proportions of apoptosis. Western blot was used to detect the expression of XIAP and Caspase-3. The activity of Caspase-3 was measured and the effect of SmacN7 combined with MMC on T24 cell lines was also determined. The results showed that SmacN7 penetratin peptide could successfully interact with endogenous XIAP, increase the proportions of apoptosis of T24 cell lines induced by low-dosage of MMC in a dose-and time-dependent manner. An obvious down-regulation of XIAP expression and up-regulation of Caspase-3 was identified by Western blot. The activity of Caspase-3 in experimental group was significantly increased as compared with that in the control group. As compared with MMC group, the viability of T24 cells in SmacN7 penetratin peptide + MMC group was markedly decreased to 2.22 and 3.61 folds at 24h and 48h respectively. It was concluded that SmacN7 penetratin peptide could act as a cell-permeable IAP inhibitor, inhibit the proliferation, induce apoptosis and enhance the chemo-sensitivity of bladder cancer cells to MMC. These findings indicate that SmacN7 penetratin peptide may be a very promising ageut for bladder cancer treatment when used in combination with chemotherapy.