Proteasome Inhibition Overcomes ALK-TKI Resistance in <i>ALK</i> -Rearranged/ <i>TP53</i> -Mutant NSCLC via Noxa Expression
Azusa Tanimoto, Shingo Matsumoto, Shinji Takeuchi, Sachiko Arai, Koji Fukuda, Akihiro Nishiyama, Kiyotaka Yoh, Takaya Ikeda, Naoki Furuya, Kazumi Nishino, Yuichiro Ohe, Kōichi Goto, Seiji Yano
Abstract
Abstract Purpose: In ALK-rearranged non–small cell lung cancer (NSCLC), impacts of concomitant genetic alterations on targeted therapies with ALK-tyrosine kinase inhibitors (ALK-TKI) are not yet well understood. Here, we investigated genetic alterations related to ALK-TKI resistance using clinico-genomic data and explored effective therapies to overcome the resistance in preclinical models through the identification of underlying molecular mechanisms. Experimental Design: We used integrated clinical and next-generation sequencing data generated in a nationwide lung cancer genome screening project (LC-SCRUM-Japan). ALK-rearranged NSCLC cell lines expressing wild-type or mutant TP53 were used to evaluate cellular apoptosis induced by ALK-TKIs. Results: In 90 patients with ALK-rearranged NSCLC who were treated with a selective ALK-TKI, alectinib, TP53 comutated patients showed significantly worse progression-free survival (PFS) than TP53 wild-type patients [median PFS, 11.7 months (95% confidence interval, CI, 6.3–not reached, NR) vs. NR (23.6–NR); P = 0.0008; HR, 0.33 (95% CI, 0.17–0.65)]. ALK-rearranged NSCLC cell lines that lost p53 function were resistant to alectinib-induced apoptosis, but a proteasome inhibitior, ixazomib, markedly induced apoptosis in the alectinib-treated cells by increasing the expression of a proapoptotic protein, Noxa, which bound to an antiapoptotic protein, Mcl-1. In subcutaneous tumor models, combination of ixazomib and alectinib prominently induced tumor regression and apoptosis even though the tumors were generated from ALK-rearranged NSCLC cells with nonfunctional p53. Conclusions: These clinical and preclinical results indicate concomitant TP53 mutations reduce the efficacy of alectinib for ALK-rearranged NSCLC and the combined use of a proteasome inhibitor with alectinib is a promising therapy for ALK-rearranged/TP53-mutated NSCLC.