Inhibiting ALK-TOPK signaling pathway promotes cell apoptosis of ALK-positive NSCLC.

T-LAK cell-oriented protein kinase (TOPK) is a potential therapeutic target in tumors. However, its role in anaplastic lymphoma kinase (ALK)-positive non-small cell lung cancer (NSCLC) has not been reported. Here, we found that TOPK was highly expressed in ALK-positive NSCLC. Additionally, ALK was identified as another upstream kinase of TOPK by in vitro kinase assay screening. Then, it was proven that ALK phosphorylated TOPK at Y74 in vitro and ex vivo, and the pathways downstream of ALK-TOPK were explored by phosphoproteomic analysis. Subsequently, we demonstrated that inhibiting TOPK enhanced tumor sensitivity to alectinib (an ALK inhibitor). The combination of alectinib and HI-032 (a TOPK inhibitor) suppressed the growth and promoted the apoptosis of ALK-positive NSCLC cells ex vivo and in vivo. Our findings reveal a novel ALK-TOPK signaling pathway in ALK-positive NSCLC. The combination of alectinib and HI-032 might be a promising therapeutic strategy for improving the sensitivity of ALK-positive NSCLC to targeted therapy.