The deubiquitinase USP34 stabilizes SOX2 and induces cell survival and drug resistance in laryngeal squamous cell carcinoma.

Recent studies showed that the deubiquitinase ubiquitin-specific protease 34 (USP34) was involved in the tumorigenesis of several tumors, but its function and mechanism are still unclear in laryngeal squamous cell carcinoma (LSCC). In this study, we found that USP34 and SOX2 were elevated in LSCC tumor tissues, and we also found that USP34 expression was positively correlated with SOX2 expression. Our further studies showed that USP34 regulated the protein level of SOX2 in LSCC cells, but not the mRNA level, which suggested that USP34 stabilized SOX2. Moreover, USP34, as a deubiquitinase, could interact with SOX2, and reduce the polyubiquitination of SOX2. In addition, knockdown of USP34 could significantly inhibit LSCC cell growth, but overexpression of SOX2 could reverse this effect. Finally, we also found that USP34 and SOX2 were upregulated in cisplatin-resistant LSCC cells, but knockdown of USP34 could enhance the drug sensitivity of cisplatin in the resistant cells. Collectively, targeting USP34/SOX2 axis may be a promising strategy for the treatment of LSCC.