He Xi, Ma Jie, Xia Jiali, Guan Zhiqiang, Jiang Guan
Department of Dermatology, The Affiliated Xuzhou Municipal Hospital of Xuzhou Medical University, Xuzhou, China.
Department of Dermatology, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, China.
Transl Cancer Res. 2025 Aug 31;14(8):4822-4836. doi: 10.21037/tcr-2024-2692-b. Epub 2025 Aug 21.
Melanoma is an aggressive skin cancer derived from melanocytes, known for its high metastatic potential and poor prognosis. Understanding the molecular mechanisms underlying melanoma progression could provide novel therapeutic targets for improving treatment outcomes. Our study aims to investigate the role of the RHO family GTPase RHOJ in melanoma progression and its regulation of cell adhesion, proliferation, and apoptosis through the Rap1 signaling pathway.
The Gene Expression Omnibus (GEO) dataset GSE122907 and the Gene Expression Profiling Interactive Analysis (GEPIA) database were used to analyze differentially expressed genes related to melanoma. A375 cells were employed as the in vitro melanoma model. The STRING database was utilized to identify RHOJ-associated genes, and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis was performed based on these genes. A375 cells were transfected with si-RHOJ, with or without the addition of a Rap1 signaling pathway activator. Cell viability was assessed using the Cell Counting Kit-8 (CCK-8) assay, while cell proliferation was measured using the 5-ethynyl-2'-deoxyuridine (EdU) assay. Apoptosis was evaluated by flow cytometry, and cell adhesion was determined using a cell adhesion detection kit. The expression of relevant genes was analyzed by real-time polymerase chain reaction (PCR), Western blot, and immunofluorescence techniques.
RHOJ, a key differentially expressed gene associated with melanoma, was significantly upregulated in melanoma cells, particularly in A375 cells. Knockdown of RHOJ reduced cell viability and proliferation, increased cell apoptosis, upregulated Bax, and downregulated Bcl-2. Additionally, cell adhesion was diminished, accompanied by the upregulation of E-cadherin and the downregulation of vinculin. The Rap1 signaling pathway was identified as a key pathway regulated by RHOJ. The levels of RAP1, RAP1GAP, and RasGRP3 were decreased in A375 cells transfected with si-RHOJ; however, these changes were reversed by activation of the Rap1 signaling pathway. Moreover, we found that the Rap1 signaling pathway activator could reverse the reduction in cell viability, proliferation, and adhesion, as well as the increase in apoptosis induced by si-RHOJ.
In conclusion, RHOJ promotes melanoma cell adhesion and proliferation while inhibiting apoptosis through the activation of the Rap1 signaling pathway, highlighting the potential clinical implications of targeting RHOJ in melanoma treatment.
黑色素瘤是一种源自黑素细胞的侵袭性皮肤癌，以其高转移潜能和不良预后而闻名。了解黑色素瘤进展的分子机制可为改善治疗结果提供新的治疗靶点。我们的研究旨在探讨RHO家族GTP酶RHOJ在黑色素瘤进展中的作用及其通过Rap1信号通路对细胞黏附、增殖和凋亡的调控。
使用基因表达综合数据库（GEO）数据集GSE122907和基因表达谱交互分析（GEPIA）数据库分析与黑色素瘤相关的差异表达基因。采用A375细胞作为体外黑色素瘤模型。利用STRING数据库鉴定与RHOJ相关的基因，并基于这些基因进行京都基因与基因组百科全书（KEGG）通路富集分析。用si-RHOJ转染A375细胞，添加或不添加Rap1信号通路激活剂。使用细胞计数试剂盒-8（CCK-8）检测法评估细胞活力，使用5-乙炔基-2'-脱氧尿苷（EdU）检测法测量细胞增殖。通过流式细胞术评估凋亡，使用细胞黏附检测试剂盒测定细胞黏附。通过实时聚合酶链反应（PCR）、蛋白质印迹法和免疫荧光技术分析相关基因的表达。
RHOJ是与黑色素瘤相关的关键差异表达基因，在黑色素瘤细胞中显著上调，尤其是在A375细胞中。敲低RHOJ可降低细胞活力和增殖，增加细胞凋亡，上调Bax并下调Bcl-2。此外，细胞黏附减少，同时E-钙黏蛋白上调，纽蛋白下调。Rap1信号通路被确定为受RHOJ调控的关键通路。在转染si-RHOJ的A375细胞中，RAP1、RAP1GAP和RasGRP3的水平降低；然而，这些变化通过激活Rap1信号通路得以逆转。此外，我们发现Rap1信号通路激活剂可逆转si-RHOJ诱导的细胞活力、增殖和黏附的降低以及凋亡的增加。
总之，RHOJ通过激活Rap1信号通路促进黑色素瘤细胞黏附和增殖，同时抑制凋亡，突出了靶向RHOJ在黑色素瘤治疗中的潜在临床意义。
