Simple SummaryMelanoma is one of the deadliest types of skin cancer, accounting for the majority of skin cancer-related deaths. The function of Nudt2 in melanoma is unknown. The goal of this study was to examine the role of Nudt2 in melanoma cells and in vivo model. In melanoma, Nudt2 appears to be a tumor-promoting gene that could be utilized as a cancer therapy target.AbstractNudt2 encodes a diadenosine tetraphosphate (Ap4A) hydrolase that catalyzes the hydrolysis of Ap4A and is involved in the lysyl tRNA synthetase-Ap4A-Nudt2 (LysRS-Ap4A-Nudt2) signaling pathway. We have previously demonstrated that this pathway is active in non-small cell lung cancer. Nudt2 was shown to be involved in cell proliferation in breast cancer, making it an important target in cancer therapy. Currently, the function of Nudt2 in malignant melanoma has not been demonstrated. Therefore, we investigated the role played by Nudt2 in the growth of human melanoma. Our study showed that Nudt2 knockdown suppressed anchorage-independent growth of human melanoma cells in vitro. The in vivo effect of Nudt2 was determined by investigating the role played by Nudt2 knockdown on the ability of the cells to form tumors in a mice xenograft model. Nudt2 knockdown significantly suppressed tumor growth in this model. Moreover, overexpression of Nudt2 resulted in an increase in anchorage-independent growth of these cells, whereas Nudt2 knockdown decreased their migration. In addition, Nudt2 knockdown reduced vimentin expression. Vimentin is one of the mesenchymal markers that are involved in the epithelial mesenchymal transition (EMT) process. Thus, Nudt2 plays an important role in promoting anchorage-independent growth and cell migration in melanoma.