The role of PICT1 in RPL11/Mdm2/p53 pathway-regulated inhibition of cell growth induced by topoisomerase IIα inhibitor against cervical cancer cell line

Abstract

Our previous work showed that a podophyllum derivative (D-3F), named 4-N-(2-Amino-3-fluoropyridine) -4-deoxidation-4′-demethylepipofophyllotoxin, inhibits the activity of topoisomerase II (TOPO II) and then results in DNA damage. Also, D-3F increases the expression of p53 to induce cervical cancer HeLa cell apoptosis by enhancing its stability, due to the translocation of RPL11 to interact with Mdm2 and then consequently causing the blockage of the Mdm2-p53 feedback loop. In present study, we further explored the detailed mechanism of the antitumor activity of D-3F against cervical cancer cell line. Firstly, the decreased level of protein interacting with carboxyl terminus 1 (PICT1) in cervical cancer cell lines (HeLa and SiHa) treated with D-3F, exerted its potent inhibitory effect on cellular proliferation, which was dependent on the inhibition of TOPO IIα activity induced by D-3F in vitro. In addition, the downregulation of PICT1 was required to enhancement of p53 stability, resulted from its promoting the nucleoplasmic translocation of RPL11 to bind to Mdm2 following D-3F treatment. Altogether, it demonstrated that the reduction of PICT1 level in HeLa cell line, as well as SiHa exposed to D-3F, a TOPO IIα inhibitor, may play an essential role in the regulation of RPL11/Mdm2/p53 pathway to induce cell apoptosis. Besides, it suggested the potential of this podophyllum derivative (D-3F) as an alternative agent for therapy in cervical cancer.