Potent USP10/13 antagonist spautin-1 suppresses melanoma growth via ROS-mediated DNA damage and exhibits synergy with cisplatin

Malignant melanoma is one of the most invasive tumours. However, effective therapeutic strategies are limited, and overall survival rates remain low. By utilizing transcriptomic profiling, tissue array and molecular biology, we revealed that two key ubiquitin-specific proteases (USPs), ubiquitin-specific peptidase10 (USP10) and ubiquitin-specific peptidase10 (USP13), were significantly elevated in melanoma at the mRNA and protein levels. Spautin-1 has been reported as a USP10 and USP13 antagonist, and we demonstrated that spautin-1 has potent anti-tumour effects as reflected by MTS and the colony formation assays in various melanoma cell lines without cytotoxic effects in HaCaT and JB6 cell lines. Mechanistically, we identified apoptosis and ROS-mediated DNA damage as critical mechanisms underlying the spautin-1-mediated anti-tumour effect by utilizing transcriptomics, qRT-PCR validation, flow cytometry, Western blotting and immunofluorescence staining. Importantly, by screening spautin-1 with targeted or chemotherapeutic drugs, we showed that spautin-1 exhibited synergy with cisplatin in the treatment of melanoma. Pre-clinically, we demonstrated that spautin-1 significantly attenuated tumour growth in a cell line-derived xenograft mouse model, and its anti-tumour effect was further enhanced by cotreatment with cisplatin. Taken together, our study revealed a novel molecular mechanism of spautin-1 effecting in melanoma and identified a potential therapeutic strategy in treatment of melanoma patients.