Role of connexin 43 in apoptosis of pancreatic cancer cell line BxPC3 / 中华胰腺病杂志

ABSTRACT

Objective To investigate the role of connexin 43(Cx43)in the apoptosis of pancreatic cancer cell line BxPC and its possible mechanism.Methods pcDNA-Cx43,pcDNA-Cx43N,pcDNA3.0,siRNA-Cx43 and siRNA-NC were transfected into BxPC3 cells via liposome method.Cx43 protein and Cytochrome C(Cyt C)concentration was determined by Western blot,and the apoptosis was analyzed by Annexin V/PI binding assay.The mitechondria apoptosis pathway involved in Cx43 associated apoptosis was examined which contains the depolarization of mitechondrial membrane potential (MMP);fluorospectrophotometer was used to measure the activities of caspase-3 and caspase-9. Gap junction intercellular communication(GJIC) was determined by dye-transfer method.Results Cx43 protein expression increased after BxPC3 transfeetion,apoptosis rate increased from(6.35±0.43)%in empty vector transfection group to(14.29±1.24)%;after H202 treatment,apoptosis rate increased from(20.34±2.47)%to(31.27±2.56)%(P<0.05).Meanwhile,mitochondrial membrane potential was decreased,Cyt C was increasingly released from mitochondria,caspases activities were increased;after siRNA43 interference,apoptosis rate decreased from(7.42±0.47)% to(5.19±1.37)%,after H_2O_2 treatment,apoptosis rate decreased from (19.43±1.71)%to(11.67±1.97)%(P<0.05).Decreased mitochondrial membrane potential and Cyt C release were observed,caspases activities were decreased.GJIC of pcDNA-Cx 43 transfection group increased from 14.52±0.57 to 23.05±3.84.and it increased from 1.70 ±0.24 to 3.84 ±0.45 in the presence of β-GA(P<0.05).But the apoptosis rate was not significantly different.Conclusions Cx43 could promote BxPC3 apoptosis via mitochondrial apoptotic signal pathway,and the possible mechanism included signal pathway other than GJIC.