<scp>CDCA4</scp> / <scp>SERTAD1</scp> / <scp>E2F1</scp> Facilitates Lung Adenocarcinoma Progression by Inhibiting <scp>PINK1</scp> /Parkin‐Mediated Mitophagy

Cell division cycle-associated protein 4 (CDCA4) has the potential to indicate lung adenocarcinoma (LUAD) development, but its regulatory role in mitophagy remains unclear. This study aimed to elucidate the mitophagy regulation and therapeutic implications of CDCA4 in LUAD. CDCA4 expression was significantly elevated in LUAD clinical specimens versus paracancerous tissues and inversely correlated with mitophagy activity. Lentiviral vectors were employed to manipulate established LUAD cells, followed by treatment with chloroquine (CQ; lysosomal inhibitor) and rapamycin (autophagy inducer) in CDCA4-silenced cells. CDCA4 knockdown elevated total and mitochondrial superoxide levels, disrupted mitochondrial membrane potential, activated the PINK1/Parkin pathway, enhanced LC3-II conversion, and degraded mitochondrial membrane proteins, collectively promoting mitophagy. Silencing CDCA4 suppressed malignant phenotypes (proliferation/migration), effects reversed by CQ but exacerbated by rapamycin. Mechanistically, CDCA4 interacted with SERTAD1 and E2F1 and stabilized these proteins. The promotion of mitophagy by CDCA4 silencing was impaired by the overexpression of SERTAD1 and E2F1. LUAD cells silencing CDCA4 were injected into immunodeficient mice for in vivo verification. CDCA4-silenced xenografts exhibited suppressed tumor growth, increased apoptosis, and elevated mitophagy-related markers. This study identifies the CDCA4/SERTAD1/E2F1 complex as a pivotal mitophagy-inhibitory hub in LUAD, proposing this axis as a novel predictive and therapeutic target.