Novel Role of Tribbles 2 in Cancer Drug Resistance via Cellular Trans-differentiation

2024 | Vol-1 | Issue-1 | Date of Submission: | Date of Publication:

Abstract

Advanced prostate cancer is commonly treated with androgen receptor blockers, such as enzalutamide, though resistant disease invariably develops which is lethal. Mechanisms underlying emergence of resistance are yet to be fully characterized. To understand the molecular basis of enzalutamide resistance, we developed a cell line model to mimic the clinical conditions. These cells were transcriptionally profiled by Illumina Hi-Seq whole genome gene-expression analysis. Hits were validated by RT-qPCR and Western blot. For clinical correlation, enzalutamide treated PDX and surgical prostate tumors were comprehensively analyzed. Roles of new hits were determined by shRNA, followed by cell viability, apoptosis, and molecular analysis. Pro-cancer effects were analyzed by cell proliferation, invasion, and soft-agar colony formation. We identified that Tribbles 2 (Trib2), a pseudokinase, is overexpressed in enzalutamide resistant prostate cancer cells. Elevated level of Trib2 was also observed in enzalutamide treated PDX and patient prostate tumors (warm autopsy). Trib2 protein level is especially higher in prostate cancer where the AR activity is low or absent. Forced overexpression of Trib2 results in aggressive prostate cancer cell growth and resistance to enzalutamide, apalutamide, darolutamide, and abiraterone. Conversely, inhibition of Trib2 decreases viability and re-sensitizes ERPC cells, suggesting that Trib2 is a driver for therapy-resistance. Interestingly, Trib2 downregulates luminal markers, but upregulates neuroendocrine markers via the neuronal transcription factor, BRN2, and the stemness factor, SOX2. Inhibition of either BRN2 or SOX2 also re-sensitizes ERPC cells. Altogether, these findings suggest that Trib2 confers resistance to enzalutamide via cellular trans-differentiation from luminal to neuroendocrine, involving BRN2 and SOX2.