Suryakant Niture1,2, Malathi Ramalinga2, Habib Kedir1,2, Dorrelyn Patacsil2, Samiksha S. Niture3, James Li4, Haresh Mani5, Simeng Suy4, Sean Collins4 and Deepak Kumar1,2,4 TNFAIP8 promotes prostate cancer cell survival by inducing autophagy, Oncotarget. 2018; 9:26884-26899.
1Julius L. Chambers Biomedical Biotechnology Research Institute, North Carolina Central University Durham, 27707 NC, USA
2Cancer Research Laboratory, University of the District of Columbia, Washington, 20008 DC, USA
3Catonsville High School, Catonsville, 21228 MD, USA
4Lombardi Comprehensive Cancer Center, Georgetown University, Washington, 20008 DC, USA
5Department of Pathology, Inova Fairfax Hospital, Falls Church, 22042 VA, USA
Tumor necrosis factor-α-inducible protein 8 (TNFAIP8) is a TNF-α inducible anti-apoptotic protein with multiple roles in tumor growth and survival. Mechanisms of cell survival by TNFAIP8 remain elusive. We investigated the role of TNFAIP8 in the regulation of the cell cycle, autophagy, cell survival and neuroendocrine differentiation in prostate cancer cells. We showed that TNFAIP8 dysregulates cell-cycle-related proteins, in PC3 cells. Oncogenic cell survival, drug resistance and dysregulation of cell cycle-related proteins are often associated with autophagy. We demonstrated that TNFAIP8 induces autophagy by increasing expression of autophagy effectors such as LC3β I/II, Beclin1, 4EBP1, p62, and SIRT1. We also demonstrated that TNFAIP8 interacts with autophagy-related protein 3 (ATG3). TNFα treatment increased the expression of TNFAIP8, which was associated with increased autophagy and decreased apoptosis. We also observed an increase in expression of neuroendocrine differentiation markers, synaptophysin and chromogranin A, and drug resistance to anticancer drugs, docetaxel and doxorubicin, in cells transfected with TNFAIP8. Collectively, our findings reveal that by the creation of cellular autophagy events, TNFAIP8 promotes cell survival and drug resistance in prostate cancer cells.