Mitochondrial carrier homolog 2 is important for mitochondrial functionality and non-small cell lung cancer cell growth

Discovering new molecular targets for non-small cell lung cancer (NSCLC) is critically important. Enhanced mitochondrial function can promote NSCLC progression by enabling metabolic reprogramming, resistance to apoptosis, and increased cell proliferation. Mitochondrial carrier homolog 2 (MTCH2), located in the outer mitochondrial membrane, is pivotal in regulating mitochondrial activities. This study examines MTCH2 expression and its functional role in NSCLC. Bioinformatic analysis showed that MTCH2 is overexpressed in NSCLC tissues, correlating with poor prognosis and other key clinical parameters of the patients. In addition, single-cell sequencing data revealed higher MTCH2 expression levels in cancer cells of NSCLC tumor mass. Moreover, MTCH2 is also upregulated in locally-treated NSCLC tissues and multiple primary/established human NSCLC cells. In various NSCLC cells, silencing MTCH2 via targeted shRNA or knockout (KO) using the CRISPR/Cas9 method significantly hindered cell proliferation, migration and invasion, while inducing apoptosis. MTCH2 knockdown or KO robustly impaired mitochondrial function, as indicated by reduced mitochondrial respiration, decreased complex I activity, lower ATP levels, lower mitochondrial membrane potential (mitochondrial depolarization), and increased reactive oxygen species (ROS) production. Conversely, ectopic overexpression of MTCH2 in primary NSCLC cells enhanced mitochondrial complex I activity and ATP production, promoting cell proliferation and migration. In vivo, the intratumoral injection of MTCH2 shRNA adeno-associated virus (aav) impeded the growth of subcutaneous xenografts of primary NSCLC cells in nude mice. In MTCH2 shRNA aav-injected NSCLC xenograft tissues, there was decreases in MTCH2 expression, mitochondrial complex I activity, ATP content, and the glutathione (GSH)/glutathione disulfide (GSSG) ratio, but increase in thiobarbituric acid reactive substances (TBAR) activity. Additionally, MTCH2 silencing led to reduced Ki-67 staining but increased apoptosis in NSCLC xenografts. Collectively, these findings demonstrate that overexpressed MTCH2 promotes NSCLC cell growth potentially through the maintenance of mitochondrial hyper-function, highlighting MTCH2 as a novel and promising therapeutic target for treating this disease.