VSIG-3/IGSF11 silencing in A2058 melanoma cells simultaneously suppresses melanoma progression and induces anti-tumoral cytokine profile in human T cells: In silico and in vitro study.

Abstract

VISTA is a newly discovered immune checkpoint whose functional mechanisms have become increasingly important to study due to its brilliant results in cancer immunotherapy. Despite VSIG-3/IGSF11 being identified as an inhibitory ligand for VISTA with potential as a target for cancer immunotherapy, very little is known of its functions. This study aimed to conduct a detailed analysis of VSIG-3/IGSF11 in melanoma, as well as to study the effects of its silencing on melanoma cell line progression and human T cell functions. Online databases were used to investigate VSIG-3/IGSF11 expression, its relationships, and prognostic value in melanoma. Then, the effects of VSIG-3/IGSF11 silencing on proliferation, migration, cell cycle arrest, and apoptosis in A2058 melanoma cells were assessed using MTT, colony formation, wound healing, cell cycle, and Annexin-V FITC/PI assays, respectively. Finally, A2058 cells transfected with VSIG-3/IGSF11 siRNA were co-cultured with human T cells, and the expression levels of T cell cytokines were evaluated using qRT-PCR. VSIG-3/IGSF11 expression was significantly increased in melanoma patients and cell lines; however, no correlation was found between VSIG-3/IGSF11 expression levels and clinicopathological characteristics, survival, or immune cell infiltration. Following VSIG-3/IGSF11 silencing in A2058 cells, viability, proliferation, and migration rates were decreased, while apoptosis was increased. T cells co-cultured with VSIG-3/IGSF11 siRNA-transfected A2058 cells exhibited increased expression levels of IFN-γ and IL-12 and decreased expression levels of IL-10, TGF-β, and TNF-α. The inhibitory effect of VSIG-3/IGSF11 silencing on A2058 melanoma cell progression, along with the alteration of T cell cytokines towards a pro-inflammatory phenotype, suggests that VSIG-3/IGSF11 is primarily involved in melanoma progression and modulating immune responses. Therefore, it may be a valuable target for immunotherapy in melanoma patients.