The LEDGF/p75 Integrase Binding Domain Interactome Contributes to the Survival, Clonogenicity, and Tumorsphere Formation of Docetaxel-Resistant Prostate Cancer Cells.

Greisha L Ortiz-Hernandez,Sourav Roy,Carlos A Casiano,Evelyn S Sanchez-Hernandez,Pedro T Ochoa,Catherine C Elix,James R W Mcmullen,Ubaldo Soto,Hossam R Alkashgari,Shannalee R Martinez,Michael Mahler,Carlos J Diaz Osterman

doi:10.3390/cells10102723

Greisha L Ortiz-Hernandez, Sourav Roy + Show 10 more

Open Access

https://doi.org/10.3390/cells10102723

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Abstract

Patients with prostate cancer (PCa) receiving docetaxel chemotherapy invariably develop chemoresistance. The transcription co-activator lens epithelium-derived growth factor p75 (LEDGF/p75), also known as DFS70 and PSIP1, is upregulated in several human cancers, including PCa and promotes resistance to docetaxel and other drugs. The C-terminal region of LEDGF/p75 contains an integrase binding domain (IBD) that tethers nuclear proteins, including the HIV-1 integrase and transcription factors, to active chromatin to promote viral integration and transcription of cellular survival genes. Here, we investigated the contribution of the LEDGF/p75 IBD interactome to PCa chemoresistance. Quantitative immunoblotting revealed that LEDGF/p75 and its IBD-interacting partners are endogenously upregulated in docetaxel-resistant PCa cell lines compared to docetaxel-sensitive parental cells. Using specific human autoantibodies, we co-immunoprecipitated LEDGF/p75 with its endogenous IBD-interacting partners JPO2, menin, MLL, IWS1, ASK1, and PogZ, as well as transcription factors c-MYC and HRP2, in docetaxel-resistant cells, and confirmed their nuclear co-localization by confocal microscopy. Depletion of LEDGF/p75 and selected interacting partners robustly decreased the survival, clonogenicity, and tumorsphere formation capacity of docetaxel-resistant cells. These results implicate the LEDGF/p75 IBD interactome in PCa chemoresistance and could lead to novel therapeutic strategies targeting this protein complex for the treatment of docetaxel-resistant tumors.

Highlights

Prostate cancer (PCa) is the most frequently diagnosed cancer among American men, with approximately 248,530 new cases and 34,130 deaths estimated in 2021 in the UnitedStates [1]
We included inASK1, our analysis c-MYC, anARinteracting independent DTX-resistant PC3-DR and DU145-DR cell lines compared to their drug-senpartner of JPO2 [44], and HRP2, which is not considered an integrase binding domain (IBD)-binding protein but shares sitive, parental counterparts
The upregulation of the LEDGF/p75 IBD interactome in DTX-resistant prostate cancer (PCa) cells and its impact on cell survival led us to investigate the effects of individual silencing of LEDGF/p75, JPO2, and menin on the clonogenicity and tumorsphere formation capacity of PC3-DR and DU145-DR cells

Summary

Introduction

Prostate cancer (PCa) is the most frequently diagnosed cancer among American men, with approximately 248,530 new cases and 34,130 deaths estimated in 2021 in the UnitedStates [1]. Despite recent advances in the treatment of mCRPC, PCa still remains incurable due to the activation of multiple mechanisms that promote tumor cell resistance to ARSI and taxane chemotherapy [3,4]. A full understanding of these mechanisms is urgently needed to develop novel and more effective treatments for therapy-resistant PCa. Emerging evidence indicates that tumors exposed to therapeutic drugs for prolonged periods undergo a reprogramming that results in the expansion of cancer stem cell (CSC). We reported that the transition of chemosensitive mCRPC cells to taxane resistance is characterized by the activation of a transcriptomic program associated with increased epithelial-to-mesenchymal transition (EMT) and stemness, and upregulation of cancer cell survival proteins, such as lens epithelium-derived growth factor of 75 kD (LEDGF/p75)

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