Role Of REV3L In Regulating The Chemosensitivity Of Cervical Cancer Cells And Study Of The Mechanisms

Objectives. REV3L, the catalytic subunit of DNA Polymerase (?) (Po(?), plays a significant role in the DNA damage tolerance mechanism of translesion synthesis (TLS). The role of REV3L in chemosensitivity of cervical cancer and its mechanism needs exploration.Methods. We evaluated the expression of Po(?) protein in 123 paraffin-embedded cervical cancer tissues and 17 normal cervical tissues using immunohistochemistry. We transfected REV3L shRNA into cervical cancer cell lines with high expression of REV3L and REV3L cDNA were delivered into cervical cancer cell lines with low expression of REV3L, and we explored the effect of REV3L on cell proliferation, cell cycle and colony formation ability. Then we assessed the cytotoxicity of cisplatin by Cell Counting Kit-8 (CCK-8) assay, apoptosis rates by apoptosis analysis using flow cytometry after exposure to cisplatin, expression changes of anti-apoptotic proteins B-cell lymphoma 2 (Bcl-2), myeloid cell leukemia sequence 1 (Mcl-1) and B-cell lymphoma-extra large (Bcl-xl) and proapoptotic Bcl-2-associated x protein (Bax) by western blotting after cisplatin treatment. We used immunofluorescence to detect y-H2AX foci after cisplatin treatment.Results. The expression of Po(?) in cervical cancer is higher than that in normal tissue samples (P<0.05). Suppression of REV3L expression inhibits cell proliferation through G1/S arrest, and enhancement of REV3L expression promotes cell proliferation by inducing G1 phase to S phase transition. Suppression REV3L expression inhibits colony formation ability, and enhancement of REV3L expression promotes colony formation ability. Suppression of REV3L enhances the sensitivity of cervical cancer cells to cisplatin, and the overexpression of REV3L confers resistance to cisplatin as evidenced by the alteration of apoptosis rates, and significantly expression level changes of Bcl-2, Mcl-1, Bcl-xl, Bax and vice versa. Immunofluorescence shows cells deficient in REV3L expression exhibited intense y-H2AX staining in comparison with control cells after exposure to cisplatin, and cells with REV3L overexpression shows weaker y-H2AX staining compared with control cells.Conclusions. The results suggest that REV3L plays an important role in regulating cervical cancer cellular response to DNA damaging agents, which indicates the inhibition of REV3L as potential target of chemosensitizer of cervical cancer.