Suppression of IGHG1 gene expression by siRNA leads to growth inhibition and apoptosis induction in human prostate cancer cell.

To investigate the immunoglobulin G (IgG) expression in prostate cancer cell lines and explore the effects of IGHG1 gene knockdown on PC3 cell growth and apoptosis. Flow cytometry, qPCR and western blot were used to demonstrate IgG expression in prostate cancer cell lines. PC3 cells were transfected with designed siRNA, the expression of IgG was determined by qPCR and western blot, the proliferation and apoptosis were detected by 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxy-phenyl)-2-(4-sulfophenil)-2H-tetrazolium, inner salt (MTS) and flow cytometry. The percentages of IgG in LNCaP cell membrane and cytoplasm were 2.96 and 89.22 % by flow cytometer, those of PC3 cell were 86.73 and 90.99 % respectively. The average level of IgG1 mRNA expression in PC3 cell line was significantly higher than that in LNCaP cell line (3.08 ± 0.15 vs 1.00 ± 0.37, P = 0.001). The protein level of IgG expression of PC3 cell line was 1.92 ± 0.15, compared with LNCaP cell line (1.05 ± 0.86). The expression of IgG1 mRNA and protein level in transfected PC3 cells decreased, with significant statistical differences from the blank control group (P < 0.01). The PC3 cell growth inhibition rates were 31.3 and 43.3 % in 48 and 72 h respectively. The rate of apoptotic PC3 cells were 5.29 ± 0.41 % in experimental group higher than that in control group (1.49 ± 0.29 %) (P < 0.01). IgG was identified in prostate cancer cells, and the siRNA targeted silencing of IGHG1 can inhibit cell viability and promote apoptosis, which might therefore act as a potential target in prostate cancer gene therapy.