Ubiquitin C-terminal hydrolase L1 promotes lymph node metastasis in small cell neuroendocrine carcinomas of the cervix

OBJECTIVE: To screen for specific differentially expressed genes in small cell neuroendocrine carcinoma of the cervix (SCNEC) and to further explore their roles and mechanisms in tumor progression. METHODS: Differentially expressed genes in SCNEC compared with squamous cell carcinoma (SCC) and adenocarcinoma (AC) were screened by microarray and immunohistochemical analyses. The biological functions of the identified genes were examined in a SCNEC cell line using RNA interference and over-expression plasmid-transfection technologies. Co-expression network analysis and immunoprecipitation technology were used to explore the potential mechanisms. RESULTS: Compared with SCC and AC, UCHL1 (encoding ubiquitin C-terminal hydrolase L1) was identified as a specific differentially expressed gene in SCNEC, which was positively related to lymph node metastasis (LNM). Migration and invasion of SCNEC tumor cells were induced by UCHL1 over-expression and suppressed by UCHL1 down-regulation, as shown by scratch and transwell invasion assays. Co-expression network analysis suggested that Prospero homeobox protein 1 (PROX1) might interact with UCHL1, and in vivo immunoprecipitation and western blots verified that levels of ubiquitinated PROX1 were significantly decreased following UCHL1 overexpression. CONCLUSION: UCHL1 is a potential biomarker of LNM in SCNEC. UCHL1 might promote SCNEC cell migration and invasion by reducing PROX1 ubiquitination.