RESUMO
Aberrant long noncoding RNAs just proximal to Xist (lncRNA JPX) expression levels have been detected in multiple tumors. However, whether JPX is involved in melanoma progression remains unclear. Our study showed that JPX expression is significantly increased in melanoma tissues and cell lines. To clarify the effect of JPX on cutaneous melanoma, we successfully generated JPX-overexpressing or JPX-knockdown A375 and A2058 cells. CCK-8, colony formation EdU, Transwell, and cell-cycle phase assays were performed, and subcutaneously implanted tumor models were used to determine the function of JPX in cutaneous melanoma. The results showed that JPX knockdown reduced the proliferation and migration of malignant melanoma cells both in vitro and in vivo. To further elucidate the molecular mechanism of JPX-induced cutaneous melanoma deterioration, we performed RNA pull-down, RNA immunoprecipitation, coimmunoprecipitation, Western blot, and RNA-sequence analyses. JPX can directly interact with YTHDF2 and impede the protection of YTHDF2 from ubiquitin-specific protease 10 (USP10), which promotes its deubiquitination. Thus, JPX decreases protein stability and promotes the degradation of YTHDF2, thereby stabilizing BMP2 mRNA and activating AKT phosphorylation. Overall, our study revealed a novel effect of JPX on YTHDF2 ubiquitination, suggesting the possibility of blocking the JPX/USP10/YTHDF2/BMP2 axis as a prospective therapeutic approach for cutaneous melanoma. IMPLICATIONS: This study highlights the ubiquitination effect of USP10 and JPX on YTHDF2 in cutaneous melanoma, and proposes that the JPX/USP10/YTHDF2/BMP2 axis may be a prospective therapeutic target for cutaneous melanoma.
Assuntos
Progressão da Doença , Melanoma Maligno Cutâneo , RNA Longo não Codificante , Proteínas de Ligação a RNA , Neoplasias Cutâneas , Animais , Feminino , Humanos , Masculino , Camundongos , Linhagem Celular Tumoral , Movimento Celular , Proliferação de Células , Regulação Neoplásica da Expressão Gênica , Melanoma Maligno Cutâneo/genética , Melanoma Maligno Cutâneo/patologia , Camundongos Nus , RNA Longo não Codificante/genética , RNA Longo não Codificante/metabolismo , Proteínas de Ligação a RNA/metabolismo , Proteínas de Ligação a RNA/genética , Neoplasias Cutâneas/genética , Neoplasias Cutâneas/patologia , Ubiquitina Tiolesterase/genética , Ubiquitina Tiolesterase/metabolismoRESUMO
In the present study, we employed the ddPCR and IHC techniques to assess the prevalence and roles of RAS and RAF mutations in a small batch of melanoma (n = 22), benign moles (n = 15), and normal skin samples (n = 15). Mutational screening revealed the coexistence of BRAF and NRAS mutations in melanomas and nevi and the occurrence of NRAS G12/G13 variants in healthy skin. All investigated nevi had driver mutations in the BRAF or NRAS genes and elevated p16 protein expression, indicating cell cycle arrest despite an increased mutational burden. BRAF V600 mutations were identified in 54% of melanomas, and NRAS G12/G13 mutations in 50%. The BRAF mutations were associated with the Breslow index (BI) (p = 0.029) and TIL infiltration (p = 0.027), whereas the NRAS mutations correlated with the BI (p = 0.01) and the mitotic index (p = 0.04). Here, we demonstrate that the "young" ddPCR technology is as effective as a CE-IVD marked real-time PCR method for detecting BRAF V600 hotspot mutations in tumor biopsies and recommend it for extended use in clinical settings. Moreover, ddPCR was able to detect low-frequency hotspot mutations, such as NRAS G12/G13, in our tissue specimens, which makes it a promising tool for investigating the mutational landscape of sun-damaged skin, benign nevi, and melanomas in more extensive clinical studies.
