ABSTRACT
Objective To identify whether cisplatin can induce autophagy of bladder cancer T24 cells and the possible mechanism, and to observe the relationship between outophagy and apoptosis.Methods MTT assay was applied to investigate the effects of various concentration of cisplatin( 0 , 10 , 20 and 40 μg/mL) on T24 survival.TEM was performed to detect the autophagosome formation .Western blot assay was used to analyze the expression changes of LC3-Ⅱ, P62 and extracellular signal-regulated kinase ( ERK1/2 ) and p-ERK at the protein level.The effects of autophagy on the survival and apoptosis of bladder cancer cells were investiga-ted.Results DDP observably inhibited proliferation of bladder cancer cells in a dose-dependent manner ( P<0.05), the 50% inhibiting concentration(IC50) was (30.3 ±2.4)μg/mL;DDP induced autophagy of bladder cancer cells, observably increased autophagosome induced by DDP; up-regulated expression levels of LC3-Ⅱproteins ( P<0.05 ) , down-regulated expression of P62 proteins ( P<0.05 );DDP increased the protein level of p-ERK (P<0.05); The inhibitor of ERK pathway U0126 inhibited DDP-induced autophagy, as evidenced by decrease in the expression of LC3-Ⅱproteins ( P<0.05 ) .After inhibition of autophagy by WTM in DDP-treated cells, cell viability was obviously decreased and apoptosis was increased (P<0.05);DDP combined with WTM observably enhanced cleavage of poly ADP-ribose polymerase 1 ( PARP-1 ) and cleaved-caspase-3 which is apop-tosis related proteins ( P<0.05 ) .Conclusions Autophagy can protect T24 cells against ciplatin-induced apop-tosis, the possible mechanism of autophagy is the ERK signaling pathway is activated .
ABSTRACT
AIM:To investigate whether oxidative stress is able to induce autophagy in mesenchymal stem cells (MSCs), and to explore the effects of autophagy on MSC proliferation and apoptosis under oxidative stress circumstance as well as the underlying mechanism for promoting the therapeutic effects of transplanted MSCs on treating diabetes mellitus e -rectile dysfunction ( DMED) .METHODS: Hydrogen peroxide ( H2 O2 ) was applied to simulate the oxidative stress cir-cumstance.The effects of H2 O2 at concentration of 0, 50, 100, 200, 400μmol/L on the viability of MSCs were tested by the method of Trypan blue exclusion and MTT assay respectively .The methods of MTT assay , Western blot and transmis-sion electron microscope ( TEM) were used to explore the effects of H 2 O2 on MSC apoptosis and autophagy .RESULTS:The proliferation of MSCs was obviously inhibited by H 2 O2 in a dose-dependent manner ( P<0.01) and the 50%inhibiting concentration (IC50) was (384.58 ±16.89) μmol/L.H2O2 induced apoptosis and autophay of MSCs .The proliferation rate of MSCs was suppressed by H 2 O2 significantly ( P<0.05 ) , with a further decline by blockade of autophagy ( P<0.05) whereas increased by blockade of apoptosis (P<0.05).H2O2 induced MSCs apoptosis obviously (P<0.05), with an augment of apoptosis ( P<0.05) by blockade of autophagy .Furthermore, the H2 O2 increased expression of cleaved caspase-3 and cleavage of poly ADP-ribose polymerase 1 (PARP1), Which were decreased by apoptosis blockade whereas were enhanced by blockade of autopahgy .CONCLUSION:Oxidative stress plays a dual role in MSC survival , which in-duces MSC apoptosis and autophagy .Moreover , blockade of autophagy intensifies MSC apoptosis .Therefore , it is a promis-ing method to ameliorate the effects of stem-cell based therapy on DMED by enhancing protective autophagy to increase the survival rate of transplanted MSCs against oxidative stress circumstance caused by diabetes mellitus .