AIM: To investigate the effect of CP466722, an inhibitor of ataxia telangiectasia mutated protein (ATM), on the proliferation and apoptosis of human hepatocellular carcinoma HepG2 cells.METHODS: The cell viability was detected by MTT assay.The cell growth inhibition was measured by colony formation assay.The effect of CP466722 on the cell cycle distribution of the HepG2 cells was examined by flow cytometry.The cell apoptosis was analyzed by TUNEL staining.The protein expression was examined by Western blotting.RESULTS: CP466722 inhibited the cell viability and cell proliferation in a dose-dependent manner.In CP466722-treated HepG2 cells, the cell cycle was arrested in G2/M phase, and the protein levels of phosphorylated cell division cycle protein 2 (p-Cdc2), cell division cycle protein 25C (Cdc25C) and phosphorylated Cdc25C (p-Cdc25C) were inhibited, whereas the protein expression of p27 was up-regulated.CP466722 triggered the apoptosis of HepG2 cells through cleavages of caspase-3 and poly (ADP-ribose) polymerase (PARP).In addition, CP466722 increased the phosphorylation of p38 mitogen-activated protein kinase (p38 MAPK) and suppressed the expression of β-catenin and survivin in the HepG2 cells.CONCLUSION: CP466722 inhibits the proliferation and induces the apoptosis of HepG2 cells, which may be related to activating p38 MAPK and inhibiting the expression of β-catenin and survivin.

OBJECTIVE To examine the reversal effect of desipramine (DMI) on resistance to temozolomide(TMZ) in U251/TR cells and explore its mechanism. METHODS U251/TR cells were exposed to DMI (20-80μmol · L-1) or TMZ (0.5-10 mmol · L-1) for 24 h, cell viability was determined by cell counting kit-8 assay with IC50 calculated. The cytotoxicity of U251/TR cells treated with TMZ (1 or 2 mmol·L-1) in combination with DMI (20, 30 or 40 μmol · L-1) for 24 h was detected using CCK-8 assay. Synergism between DMI and TMZ was analyzed by the JIN Zheng-jun method. Apoptosis of U251/TR cells induced by TMZ 1 mmol · L-1, DMI 30 μmol · L-1,or their combination was examined by Hoechst33258 stains and caspase 3 activity was detected by luminescence analysis. Expression of C/EBP homologous protein (CHOP) was measured using quantitative real-time PCR and Western blotting. The survival rate of U251/TR cells treated with TMZ 1 mmol·L-1 and/or DMI 30μmol·L-1 was also assessed after silencing CHOP expression by small interference RNA (siRNA). RESULTS DMI or TMZ alone inhibited the growth of U251/TR cells significantly in a concentration-dependent manner (r 2=0.983,0.982,P<0.05), with the IC50 (33.6 ± 0.5)μmol · L-1 and (2.5 ± 0.6)mmol · L-1, respectively. The cell viability inhibitory rate of U251/TR cells by TMZ (1 or 2 mmol · L-1) combined with DMI (20, 30, or 40μmol · L-1) was greater than that by TMZ or DMI alone (P<0.05). The JIN Zheng-jun analysis revealed that combination of DMI and TMZ produced synergistic cytotoxicity (Q>1.15), ie, compared with TMZ alone, TMZ (1 mmol·L-1) com?bined with DMI (30 μmol · L-1) produced significant nuclear fragmentation and condensation (P< 0.05). In addition, DMI and TMZ in combination activated caspase 3 activity in U251/TR cells (P<0.05). Knock?down of CHOP by specific siRNA attenuated the synergistic effect of DMI in the presence of TMZ, the survival rate of the combined drug group raised from 51.8%to 62.2%(P<0.05). CONCLUSION The results suggest that DMI reverse resistance of U251/TR cells to TMZ through activation of the CHOP-depend?ently apoptosis pathway.

Background and Objectives: The search for a suitable alternative for urethral defect is a challenge in the field of urethral tissue engineering. Induced pluripotent stem cells (iPSCs) possess multipotential for differentiation. The in vitro derivation of urothelial cells from mouse-iPSCs (miPSCs) has thus far not been reported. The purpose of this study was to establish an efficient and robust differentiation protocol for the differentiation of miPSCs into urothelial cells. Methods: and Results: Our protocol made the visualization of differentiation processes of a 2-step approach possible. We firstly induced miPSCs into posterior definitive endoderm (DE) with glycogen synthase kinase-3β (GSK3β) inhibitor and Activin A. We investigated the optimal conditions for DE differentiation with GSK3β inhibitor treatment by varying the treatment time and concentration. Differentiation into urothelial cells, was directed with all-trans retinoic acid (ATRA) and recombinant mouse fibroblast growth factor-10 (FGF-10). Specific markers expressed at each stage of differentiation were validated by flow cytometry, quantitative real-time polymerase chain reaction (qRT-PCR) assay, immunofluorescence staining, and western blotting Assay. The miPSC-derived urothelial cells were successfully in expressed urothelial cell marker genes, proteins, and normal microscopic architecture. Conclusions We built a model of directed differentiation of miPSCs into urothelial cells, which may provide the evi-dence for a regenerative potential of miPSCs in preclinical animal studies.