CP466722 inhibits proliferation and triggers apoptosis of HepG2 cells / 中国病理生理杂志

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.

Reversal effects of desipramine on resistance of U251/TR cells to temozolomide / 中国药理学与毒理学杂志

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,P1.15), 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.

Perifosine regulates human brain glioma U251 cell proliferation, apopto-sis and autophagy through suppression of PI3 K/Akt pathway / 中国病理生理杂志

AIM:To investigate the effect of perifosine, an inhibitor of protein kinase B ( PKB/Akt) , on the cell cycle, apoptosis and autophagy in human brain glioma U251 cells, and to determine the relationship between perifos-ine-induced autophagy and apoptosis of glioma.METHODS:The cell growth inhibition was determined by MTT assay. The cell cycle distribution of U251 cells was examined by flow cytometry.The cell apoptosis was analyzed by Annexin V-FITC apoptosis detection kit.The protein expression of P21, P27, cyclin B1, caspase-9 and PARP was examined by Wes-tern blot analysis.The distribution and expression of LC3-Ⅱ, an autophagy marker, was observed to determine the effect of perifosine-induced autophagy.RESULTS:Perifosine inhibited the cell viability in a dose-dependent manner.In perifos-ine-treated U251 cells, the cell cycle was arrested in G2 phase and the expression of cyclin B1 was inhibited.Perifosine in-duced apoptosis of U251 cells through activation of caspase-9 cleavage, PARP cleavage and survivin inhibition.In addi-tion, suppression of autophagy by chloroquin, an inhibitor of autophagy, increased the number of apoptotic cells.CON-CLUSION:Perifosine inhibits cell proliferation and triggers apoptosis and autophagy in human U251 cells.Blocking auto-phagy magnifies perifosine-induced glioma cell apoptosis.

MK-2206, an inhibitor of Akt, induced cell apoptosis and autophagy in U2 OS cells / 中国病理生理杂志

AIM:To observe the effect of MK-2206, an inhibitor of Akt, on the cell apoptosis and autophagy of U2OS cells.METHODS:The cell viability was detected by MTT assay .The cell apoptosis was analyzed by TdT-media-ted dUTP nick end labeling assay .The expression of LC3-II was examined by Western blotting .RESULTS:MK-2206 in-hibited the cell viability in a dose-dependent manner .MK-2206 induced the cell apoptosis via activation of caspase-3, caspase-9 and PARP.MK-2206 treatment substantially induced the U 2OS cell autophagy by increasing in the levels of LC 3-II.Blockage of autophagy using chloroquine magnified MK-2206-induced cell death in U2OS cells.CONCLUSION:The Akt inhibitor MK-2206 induces cell apoptosis and autophagy .Blocking autophagy magnifies MK-2206-induced the inhibi-tion of the viability in U2OS cells.