It has been reported that ubiquitin C-terminal hydrolase-L3 (UCHL3) plays an important role in cancer development; however, the role of UCHL3 in melanoma remains unclear. The present study aimed to investigate the role of ubiquitin C-terminal hydrolase-L3 (UCHL3) and determine its underlying molecular mechanisms in melanoma occurrence and development using in vitro studies. Reverse transcription-quantitative PCR analysis was performed to detect UCHL3 mRNA expression. The MTT assay was performed to assess cell proliferation. Cell apoptosis was analyzed via flow cytometry and the TUNEL assay. Cell ultrastructure was observed via transmission electron microscopy. LC3B protein expression was detected via cellular immunofluorescence, while neural precursor cell-expressed developmentally downregulated protein 8 (NEDD8) and LC3 protein expression levels, and NEDD8 ubiquitination were detected via western blot analysis. The results demonstrated that transfection with small interfering (si)RNA-UCHL3 significantly suppressed cell proliferation, whereas apoptosis was significantly enhanced, as well as autophagy, autophagosome formation and LC3B protein expression. In addition, NEDD8 protein expression and autophagosome numbers significantly decreased, while the LC3II/LC3I ratio significantly increased. NEDD8 knockdown via transfection with si-NEDD8 had similar effects to si-UCHL3, as well as si-UCHL3+ si-NEDD8. Taken together, the results of the present study suggest that UCHL3 knockdown decreases melanoma cell proliferation by increasing cell autophagy through regulating NEDD8 expression and autophagosome numbers.
Keywords: autophagosome; autophagy; melanoma; neural precursor cell-expressed developmentally downregulated protein 8; ubiquitin C-terminal hydrolase-L3.
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