Ubiquitin-specific protease 44 inhibits cell proliferation and migration via inhibition of JNK pathway in clear cell renal cell cancer

Abstract Background: Clear cell renal cell carcinoma (ccRCC) is one of the most common malignancies. USP44 has been reported to be involved in various cancers. This study aimed to investigate the function role and molecular mechanism of USP44 in ccRCC. Methods: Data obtained from TCGA data portal and GSO database were analyzed to uncover the clinical relevance of USP44 expression and tumor development. The function of USP44 in cell proliferation and migration was assessed by cellular and molecular analysis. Results: USP44 was lowly expressed in the ccRCC cancer tissues compared to the normal tissue. Further, USP44 expression was negatively correlated with tumor stage, tumor grade, and patient survival . USP44 overexpression significantly inhibited tumor cell proliferation and migration of 786-O cell as well as Caki-1 cell. In addition, USP44 overexpression also prohibited cell proliferation by up-regulating P21, down-regulating Cyclin D1 expression, and inhibited cell migration by up-regulating MMP2 and MMP9 expression. In contrast, USP44 knockdown enhances ccRCC cell proliferation and migration. Furthermore, the USP44 function in inhibiting ccRCC cell proliferation and migration is associated with the phosphorylation level of JNK. Conclusion: In summary, this study showed that USP44 may be a marker in predicting the ccRCC progression and USP44 inhibits ccRCC cell proliferation and migration dependent on the JNK pathway.