Targeting YAP to overcome acquired resistance to ALK inhibitors in ALK-rearranged lung cancer.

Clinical benefit of ALK tyrosine kinase inhibitors (ALK-TKIs) in ALK-rearranged lung cancer has been limited by the inevitable development of acquired resistance, and bypass-molecular resistance mechanisms remain poorly understood. We investigated a novel therapeutic target through screening FDA-approved drugs in ALK-TKI-resistant models. Cerivastatin, the rate-limiting enzyme inhibitor of the mevalonate pathway, showed anti-cancer activity against ALK-TKI resistance in vitro/in vivo, accompanied by cytoplasmic retention and subsequent inactivation of transcriptional co-regulator YAP. The marked induction of YAP-targeted oncogenes (EGFR, AXL, CYR61, and TGFβR2) in resistant cells was abolished by cerivastatin. YAP silencing suppressed tumor growth in resistant cells, patient-derived xenografts, and EML4-ALK transgenic mice, whereas YAP overexpression decreased the responsiveness of parental cells to ALK inhibitor. In matched patient samples before/after ALK inhibitor treatment, nuclear accumulation of YAP was mainly detected in post-treatment samples. High expression of YAP in pretreatment samples was correlated with poor response to ALK-TKIs. Our findings highlight a crucial role of YAP in ALK-TKI resistance and provide a rationale for targeting YAP as a potential treatment option for ALK-rearranged patients with acquired resistance to ALK inhibitors.