Targeting CHCHD3 inhibits tumorigenesis of NSCLC by Reprogramming Mitochondrial Metabolism

BACKGROUND: Mitochondria are essential organelles for cellular metabolism and tumor formation. We discovered that CHCHD3 is an important inner mitochondria membrane protein involved in the proliferation of lung adenocarcinoma (LUAD). However, the molecular pathways through which CHCHD3 contributes to cancer progression remain poorly understood. METHODS: Following CHCHD3 knockdown, cell proliferation was assessed by CCK8 assay, colony formation assay, and cell cycle analysis. Apoptosis, intracellular Reactive Oxygen Species (ROS) levels, and mitochondrial membrane potential were evaluated using flow cytometry, JC-1 staining, and Western blot analysis, respectively. Mitochondrial function was measured using a Seahorse analyzer. Immunoprecipitation coupled with mass spectrometry (IP-MS) and Co-immunoprecipitation (CO-IP) were used to identify CHCHD3-interacting proteins. RESULTS: CHCHD3 expression was significantly upregulated in lung cancer tissues, with its overexpression correlating with poor patient survival. In LUAD cells, CHCHD3 knockdown suppressed proliferation, induced G1 cell cycle arrest, and triggered cellular dysfunction, including apoptosis and mitochondrial energy metabolism impairment. IP-MS screening identified several potential CHCHD3-interacting proteins, among which SAMM50 and VDAC1/2 were validated as direct binding partners. Dysregulation of these interactions may underlie the excessive production of ROS observed upon CHCHD3 loss. DISCUSSION: Our results demonstrate that CHCHD3 is highly expressed in lung adenocarcinoma and positively correlates with poor prognosis. Mechanistically, CHCHD3 loss is associated with mitochondrial dysfunction, ROS accumulation, and activation of the intrinsic apoptotic pathway. CONCLUSION: Our study identifies CHCHD3 as a mitochondrial protein upregulated in lung cancer that contributes to tumor cell proliferation and survival.