Androgen-ablative therapies inducing CXCL8 regulates mTORC1/SREBP2-dependent cholesterol biosynthesis to support progression of androgen receptor negative prostate cancer cells

Abstract

Treatment with androgen-ablative therapies effectively inhibited androgen receptor (AR)-positive (AR+) prostate cancer (PCa) cell subtypes, but it resulted in an increase in AR-negative (AR−) PCa cell subtypes. The present study aimed to investigate the debated mechanisms responsible for the changing proportion of cell types, identifying CXCL8 as a synthetic essential effector of AR− PCa cells. AR− PCa cells were found to be susceptible to CXCL8 depletion or inhibition, which impaired their survival. Mechanistically, androgen-ablative therapies resulted in the suppression of AR signaling, leading to the upregulation of CXCL8 gene transcription. CXCL8, in turn, activated the mTORC1 pathway, which increased de novo cholesterol synthesis by activating sterol regulatory element-binding protein-2 (SREBP2). Together, these results suggested that the CXCL8-mTORC1-SREBP2 axis contributed to the exacerbation of tumorigenicity in AR− PCa cells under androgen-ablative therapies.