GX-BP1: Targeting SOX2 to Prevent Resistance in mCRPC

GX-BP1, a bioPROTAC-based SOX2 degrader, selectively targets SOX2, an undruggable protein, for ubiquitin-proteasome elimination, overcoming limitations of prior inhibition strategies. In preclinical models, GX-BP1 monotherapy delivered approximately 70% tumor growth inhibition, while combinations with agents like carboplatin/paclitaxel achieved 87-96% inhibition and near-complete tumor suppression at optimal doses. Notably, GX-BP1 paired with osimertinib eradicated cancer stem cells and fully prevented tumor regrowth, directly countering SOX2-mediated resistance mechanisms prevalent in prostate cancer.
SOX2, a key transcription factor, drives prostate cancer progression by promoting cancer stem cell maintenance, epithelial-mesenchymal transition, metastasis, and resistance to androgen deprivation therapy and chemotherapy. In castration-resistant prostate cancer (CRPC), elevated SOX2 expression fosters lineage plasticity toward aggressive neuroendocrine phenotypes, upregulates survival pathways like PI3K/AKT and Wnt/β-catenin, and enables tumor quiescence that evades drugs such as enzalutamide or docetaxel, leading to rapid relapse and poor outcomes.

For prostate cancer patients, GX-BP1 offers a promising avenue against high-SOX2 tumors, which correlate with faster spread and therapy failure. By dismantling stemness and restoring sensitivity to standard treatments, it could prolong progression-free survival in CRPC and neuroendocrine subtypes.

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