Inhibition of AKT sensitizes cancer cells to antineoplastic drugs by down-regulating Flap Endonuclease 1

DNA repair mechanisms are crucial for cell survival. It increases the cancer cell9s ability to resist DNA damage. FEN1 involves in DNA replication and repair, specifically long patch base excision repair. Although the gene function and post-translational modification of FEN1 are well studied, the regulatory mechanism of FEN1 by upstream signal pathways remains unclear. In this paper, we have identified AKT as a regulator of FEN1 activity in lung cancer cells. Sustained activation of AKT can phosphorylate nuclear transcription factor NFκB/p65. NFκB/p65 directly binds to FEN1 promoter to promote high transcription level of FEN1, revealing the contribution of AKT signalling pathway to drug resistance of cancer cells. The combination of an AKT inhibitor and cisplatin efficiently suppressed lung cancer cell growth both in vitro and in vivo. Our study illustrated a mechanism about upstream regulatory mechanism of FEN1, and this will contribute to the development of effective lung cancer therapies.