Effect of actin related protein 2/3 complex subunit 2 gene silencing on the proliferation and apoptosis of papillary thyroid carcinoma TPC-1 cells

Objective To investigate the effect of actin related protein 2/3 complex subunit 2 (ARPC2) gene silencing on the biological characteristics of papillary thyroid carcinoma (PTC) TPC-1 cells through lentivirus-mediated RNA interference. Methods TPC-1 cells infected with nonsense short hairpin RNA (shRNA) sequence lentivirus (shCtrl) was used as the control group. TPC-1 cells infected with ARPC2 shRNA interference sequence lentivirus (shARPC2) was used as the experimental group, in which the expression of ARPC2 gene was specifically interfered. The effects of silencing the expression of ARPC2 gene on the proliferation of TPC-1 cells were detected by using methyl thiazolyl tetrazolium (MTT) assay, flow cytometry, Western blot and colony formation test. Flow cytometry and Western blot were conducted to detect the effect of silencing ARPC2 gene on TPC-1 cells apoptosis and related proteins. Results shARPC2 could efficiently infect TPC-1 cells, and the expression efficiency of green fluorescent protein was over 85%. Compared with the control group, TPC-1 proliferation was inhibited in the experimental group. The ratio of S-phase cells in the experimental group was reduced compared with that in the control group [(14.79±0.21)% vs. (21.13±0.33)%, t = 27.77, P < 0.05]. The ratio of G1 and G2/M-phase cells in the experimental group was increased compared with that in the control group [G1 phase: (67.57±0.08)% vs. (62.06±0.36)%, t=25.56, P < 0.05; G2/M phase: (17.64±0.12)% vs. (16.91±0.17)%, t=6.154, P < 0.05]. Meanwhile, the expressions of cell cycle-related proteins CDK2, CyclinE and CyclinD were reduced in the experimental group. The number of clone formation in the experimental group was less than that in the control group, the difference was statistically significant [(10±2) vs. (161±6), t=9.011, P < 0.05]. In addition, the apoptotic ratio of cells in the experimental group was higher than that in the control group [(8.60±0.77)% vs. (4.08±0.40)%, t=9.011, P < 0.05]. Western blot showed that the expressions of anti-apoptotic factors p21 and bcl-2 were reduced in the experimental group, while the expression of pro-apoptotic factor bax was increased. Conclusion The interference with the expression of ARPC2 regulated by shRNA can inhibit the proliferation, and promote the apoptosis of PTC TPC-1 cells, indicating that ARPC2 may be a possible biological new target for the treatment of PTC. Key words: Thyroid neoplasms; RNA interference; Cell proliferation; Apoptosis