Targeting Pre-existing Club-Like Cells in Prostate Cancer Potentiates Androgen Deprivation Therapy

A critical knowledge gap in prostate cancer research is understanding whether castration-tolerant progenitor-like cells that reside in treatment-naïve tumors play a direct role in therapy resistance and tumor progression. Herein, we reveal that the castration tolerance of LSC ^med (Lin ^- , Sca-1 ⁺ , CD49f ^med ) progenitor cells, the mouse equivalent of human prostatic Club cells, arises not from intrinsic properties but from significant transcriptional reprogramming. Utilizing single-cell RNA sequencing of LSC ^med cells isolated from prostate-specific Pten-deficient (Pten ^pc-/- ) mice, we identify the emergence of castration-resistant LSC ^med cells enriched in stem-like features, driven by the transcription factor Fosl1/AP-1. We demonstrate that cells exhibiting Pten ^pc-/- LSC ^med characteristics are prevalent in the aggressive mesenchymal stem-like prostate cancer (MSPC) subtype recently identified in human castration-resistant prostate cancer (CRPC). Furthermore, our findings show that the dual-targeting agents JQ-1 and CX-6258—focused on Fosl1/AP-1 and PIM kinases, respectively—effectively suppress both the progenitor properties and the growth of mouse and human MSPC surrogates in vitro and in vivo . Thus, early eradication of castration-tolerant Club-like cells presents a promising therapeutic strategy to mitigate prostate cancer progression toward CRPC.