NME3 promotes clear cell renal cell carcinoma progression and modulates TKI response through MFN1/2-dependent mitochondrial fusion and mitophagy suppression.

Renal cell carcinoma (RCC), particularly the clear cell subtype (ccRCC), is a prevalent malignancy characterized by aggressive progression and heterogeneous therapeutic responses. Although mitochondrial dynamics are increasingly recognized as critical regulators of cancer metabolism and survival, the role of nucleoside diphosphate kinase 3 (NME3) in this process remains poorly understood. In this study, we integrated bioinformatic analyses of public datasets with validation in patient-derived tissues, in vitro functional assays, and in vivo xenograft models to elucidate the role of NME3 in ccRCC. We found that NME3 is significantly upregulated in ccRCC and correlates with poor survival, serving as an independent prognostic factor. Functionally, NME3 knockdown suppresses proliferation, migration, invasion, and xenograft tumor growth, while its overexpression promotes malignant phenotypes. Mechanistic investigations revealed that NME3 knockdown induces mitochondrial fragmentation, reduces ATP production, increases reactive oxygen species (ROS) levels, and activates PINK1/Parkin-mediated mitophagy; whereas NME3 overexpression enhances mitochondrial fusion and oxidative phosphorylation. Further analyses revealed that NME3 forms homomeric or heteromeric hexamers with NME2 and interacts with the mitochondrial fusion regulators MFN1 and MFN2 to facilitate mitochondrial fusion. Importantly, NME3 expression modulated the cellular response to tyrosine kinase inhibitors (TKIs), including sorafenib and sunitinib, with NME3 depletion enhancing drug sensitivity in vitro and in xenograft models. Collectively, these findings identify NME3 as a regulator of mitochondrial dynamics in ccRCC and highlight a potential link between mitochondrial remodeling and therapeutic response.