Effects of PPP2R5C on proliferation,apoptosis,and drug sensitivity of multiple myeloma cells
Objective To investigate the effects of protein phosphatase 2 regulatory subunit B'gamma(PPP2R5C)on the proliferation,apoptosis and drug sensitivity of multiple myeloma(MM)cells.Methods The qRT-PCR and Western blot were used to detect the expression of PPP2R5C in human multiple myeloma cell lines(MM1S and RPMI-8226 cell lines)and normal peripheral blood mononuclear cells(PBMC).The MM 1S cells were transfected with PPP2R5C interfering siRNA(si-PPP2R5C group)and its negative control(si-CTRL group),and PPP2R5C overexpressing plasmid(OE-PPP2R5C group)and its negative control(OE-CTRL group),respectively.Cell proliferation was detected by CCK-8 method,and cell apoptosis was detected by flow cytometry.The cells in the si-PPP2R5C group and si-CTRL group were treated with different concentrations of Bortezomib(BTZ)for 24 h,cell viability was measured by CCK-8 method and half maximal inhibitory concentration(IC50)values were calculated.After 1 nmol/L BTZ intervention for 24 h,the expression levels of BCL-2 and BAX in the si-PPP2R5C and si-CTRL groups were detected by qRT-PCR and Western blot,and Caspase-3/7 activity was detected by Caspase 3/7 activity detection kit,and cell apoptosis was detected by flow cytometry.Results Compared with PBMC cells,PPP2R5C was highly expressed in MM 1S and RPMI-8226 cells at both mRNA and protein levels(all P<0.001).Compared with the si-CTRL group,the cell proliferation activity of si-PPP2R5C group was inhibited after 48 h and 72 h of cell culture(all P<0.001),the apoptosis rate was significantly increased(5.97%vs 14.39%,P<0.001).Compared with the OE-CTRL group,the cell proliferation activity of OE-PPP2R5C group was enhanced at these time points after 48 h and 72 h of cell culture(all P<0.01).The IC50 value of BTZ in the si-PPP2R5C group was significantly lower than that in the si-CTRL group(3.40 nmol/L vs 10.37 nmol/L,P<0.001).Moreover,compared with the control group and si-CTRL+BTZ group,mRNA and protein level of BCL-2 in the si-PPP2R5C+BTZ group were decreased,while the mRNA and protein level of BAX,Caspase 3/7 activity and cell apoptosis rate were increased(all P<0.05).Conclusions PPP2R5C is highly expressed in MM cell lines.PPP2R5C knockdown can inhibit the cell proliferation and promote apoptosis of MM cells,and increase the drug sensitivity of BTZ.