Abstract 1503: Arsenic trioxide inhibits proliferation of acute leukemia cells through reduced expression of E2F1, cyclin E, and activation of retinoblastoma protein

Abstract

Abstract Arsenic trioxide (ATO) is has been used successfully in the treatment of all age group of acute promyelocytic leukemia (APL) patients in both induction and consolidation therapy. It inhibits growth APL cells through various mechanism including oxidative stress, cell cycle regulation, and apoptosis. However, detail molecular mechanism ATO-induced APL cell proliferation inhibition mostly poorly known. E2F1, a transcriptional factor widely involved proliferation and differention of many types of cancer cells through providing signal to accumulation p53, cell cycle regulation, and apoptosis. We hypothesized that ATO inhibits proliferation and differentiation of APL cells through reduced expression of E2 F1, cyclin E and stimulation of retinoblastoma and AMPKα2 expressions in APL cells. To test hypothesis, we used APL cell lines and after treatment with different concentration (2,4,6, and 8μg/ml) ATO, checked expression level of E2F1, cyclin A, cyclin E, Akt, retinoblastoma (Rb D20 & H1) and AMPKα2 by western blotting, immunocytochemistry, and confocal imaging. We found that it reduced expression significantly of E2F1, cyclin E by modulating expression profile of retinoblastoma (Rb D20 & H1), Akt and AMPKα2 proteins in APL cells concentration dependent manner. Our data showed that E2F1 associated with p53 and its association may involve ATO -induced cell cycle regulation and apoptosis. On the basis of these findings, we conclude that ATO inhibits APL cells proliferation by reducing E2F1, cyclin E expression through stimulation of retinoblastoma (Rb D20 & H1), Akt , and AMPKα2 proteins. It is novel mode of action of ATO in APL cells and may help in the designing of new anti-leukemic drugs for treatment of APL patients more efficiently and quickly. Keywords: Arsenic trioxide, E2F1, cyclin E, Rb proteins, AMPKα2, and APL cells. Acknowledgements: This research was financially supported by National Institutes of Health NCRR Grant No. 5G12RR013459 and MIMHD Grant No. 8G12MD007581, through the RCMI-Center for Environmental Health at Jackson State University. Citation Format: Sanjay Kumar, Paul Tchounwou. Arsenic trioxide inhibits proliferation of acute leukemia cells through reduced expression of E2F1, cyclin E, and activation of retinoblastoma protein [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1503.