DAZAP1 Phase Separation Regulates Mitochondrial Metabolism to Facilitate Invasion and Metastasis of Oral Squamous Cell Carcinoma.

Tumor invasion and metastasis are the underlying causes of the high mortality rate of oral squamous cell carcinoma (OSCC). Energy metabolism reprogramming has been identified as a crucial process mediating tumor metastasis, thus indicating an urgent need for in-depth investigation of the specific mechanisms of tumor energy metabolism. Here, we identified an RNA-binding protein, DAZ associated protein 1 (DAZAP1), as a tumor-promoting factor with an important role in OSCC progression. DAZAP1 was significantly upregulated in OSCC, which enhanced the migration and invasion of OSCC cells and induced the epithelial-mesenchymal transition (EMT). RNA-seq analysis and experimental validation demonstrated that DAZAP1 regulates mitochondrial energy metabolism in OSCC. Mechanistically, DAZAP1 underwent liquid-liquid phase separation (LLPS) to accumulate in the nucleus where it enhanced cytochrome-c oxidase 16 (COX16) expression by regulating pre-mRNA alternative splicing, thereby promoting OSCC invasion and mitochondrial respiration. In mouse OSCC models, loss of DAZAP1 suppressed EMT, downregulated COX16, and reduced tumor growth and metastasis. In OSCC patient samples, expression of DAZAP1 positively correlated with COX16, and high expression of both proteins was associated with poor patient prognosis. Together, these findings revealed a mechanism by which DAZAP1 supports mitochondrial metabolism and tumor development of OSCC, suggesting the potential of therapeutic strategies targeting DAZAP1 to block OSCC invasion and metastasis.