RFC5 Targets CDK1 to Trigger Mitochondrial Fission and Facilitate Non-Small Cell Lung Cancer Progression

Background: The worldwide mortality from non-small cell lung cancer (NSCLC) is high, with a scarcity of effective therapies for advanced cases. Mitochondrial dynamics, particularly fission, is vital in cancer cell survival and progression. Herein, we examined how replication factor C 5 (RFC5), a DNA replication factor, influences mitochondrial fission and apoptosis in NSCLC.Methods: Integrated bioinformatic analysis of the NSCLC-related dataset GSE19188 and apoptosis- and mitochondrial dynamics-related genes from GeneCards was performed to screen and identify RFC5 as a key candidate gene closely associated with NSCLC progression. We conducted in vitro functional validation and mechanistic dissection in A549 cells, including gain/loss-of-function experiments, cell proliferation, migration and invasion assays, flow cytometry, and co-immunoprecipitation to validate its oncogenic function and elucidate the underlying mechanism. Molecular docking between RFC5 and cyclin-dependent kinase 1 (CDK1), as well as rescue experiments with a dynamin-related protein 1 (DRP1) inhibitor (Mdivi-1), further delineated the signaling axis.Results: RFC5 was identified as upregulated in NSCLC samples in GSE19188 (p < 0.05) and functional studies were conducted in A549 cells, and elevated RFC5 significantly promoted cell proliferation, migration, and invasion, while markedly blocking apoptosis (p < 0.05). Mechanistically, RFC5 physically interacted with CDK1, enhancing its expression. This RFC5-CDK1 axis facilitated DRP1-mediated mitochondrial fission, as evidenced by decreased mitochondrial membrane potential and altered expression of fission/fusion genes (p < 0.05). Importantly, the inhibitory effects of RFC5 silencing were reversed by CDK1 overexpression, whereas DRP1 inhibitor Mdivi-1 abolished the effects of CDK1 overexpression (p < 0.05).Conclusion: Our findings unveil a potential RFC5-CDK1 signaling axis that may promote NSCLC cell progression in vitro by modulating mitochondrial fission and inhibiting apoptosis, highlighting a novel avenue for NSCLC intervention.