A kinome-wide CRISPR screen identifies CK1 as a novel target to overcome enzalutamide resistance of prostate cancer

Abstract Enzalutamide (ENZA), a second-generation androgen receptor antagonist, has significantly increased progression-free and overall survival of patients with metastatic prostate cancer (PCa). However, resistance remains a prominent obstacle in treatment, illustrating the urgent need to develop new approaches to increase ENZA efficacy. Utilizing a kinome-wide CRISPR-Cas9 knockout screen, we identified casein kinase 1 alpha (CK1α) as a novel therapeutic target to overcome ENZA resistance. Depletion or pharmacologic inhibition of CK1α significantly enhanced EZNA efficacy in ENZA-resistant cell lines and patient-derived xenografts. Mechanistically, CK1α phosphorylates the serine residue S1270 and modulates the protein abundance of ataxia-telangiectasia mutated (ATM), a primary initiator of DNA double-strand break (DSB)-response signaling, which is compromised in ENZA-resistant cells and patients. Inhibition of CK1α stabilizes ATM, resulting in the restoration of DSB-response signaling, and thus increases ENZA-induced cell death and growth arrest in an ATM-dependent manner. Our study details an innovative therapeutic approach for ENZA-resistant PCa and characterizes a novel perspective for the function of CK1α in the regulation of DNA damage response signaling.