Dataset Information

Interferon-? Signaling in Melanocytes and Melanoma Cells Regulates Expression of CTLA-4.

ABSTRACT: CTLA4 is a cell surface receptor on T cells that functions as an immune checkpoint molecule to enforce tolerance to cognate antigens. Anti-CTLA4 immunotherapy is highly effective at reactivating T-cell responses against melanoma, which is postulated to be due to targeting CTLA4 on T cells. Here, we report that CTLA4 is also highly expressed by most human melanoma cell lines, as well as in normal human melanocytes. Interferon-? (IFNG) signaling activated the expression of the human CTLA4 gene in a melanocyte and melanoma cell-specific manner. Mechanistically, IFNG activated CTLA4 expression through JAK1/2-dependent phosphorylation of STAT1, which bound a specific gamma-activated sequence site on the CTLA4 promoter, thereby licensing CBP/p300-mediated histone acetylation and local chromatin opening. In melanoma cell lines, elevated baseline expression relied upon constitutive activation of the MAPK pathway. Notably, RNA-seq analyses of melanoma specimens obtained from patients who had received anti-CTLA4 immunotherapy (ipilimumab) showed upregulation of an IFNG-response gene expression signature, including CTLA4 itself, which correlated significantly with durable response. Taken together, our results raise the possibility that CTLA4 targeting on melanoma cells may contribute to the clinical immunobiology of anti-CTLA4 responses.Significance: These findings show that human melanoma cells express high levels of the immune checkpoint molecule CTLA4, with important possible implications for understanding how anti-CTLA4 immunotherapy mediates its therapeutic effects. Cancer Res; 78(2); 436-50. ©2017 AACR.

SUBMITTER: Mo X

PROVIDER: S-EPMC5771950 | biostudies-literature | 2018 Jan

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Interferon-γ Signaling in Melanocytes and Melanoma Cells Regulates Expression of CTLA-4.

Mo Xuan X Zhang Hanghang H Preston Sarah S Martin Kayla K Zhou Bo B Vadalia Nish N Gamero Ana M AM Soboloff Jonathan J Tempera Italo I Zaidi M Raza MR

Cancer research 20171117 2

CTLA4 is a cell surface receptor on T cells that functions as an immune checkpoint molecule to enforce tolerance to cognate antigens. Anti-CTLA4 immunotherapy is highly effective at reactivating T-cell responses against melanoma, which is postulated to be due to targeting CTLA4 on T cells. Here, we report that CTLA4 is also highly expressed by most human melanoma cell lines, as well as in normal human melanocytes. Interferon-γ (IFNG) signaling activated the expression of the human CTLA4 gene in ...[more]

PMID: 29150430

Similar Datasets

Project description:Expression of Nodal, a Transforming Growth Factor-beta (TGF-?) related growth factor, is associated with aggressive melanoma. Nodal expression in adult dysplastic nevi may predict the development of aggressive melanoma in some patients. A subset of pediatric patients diagnosed with giant or large congenital melanocytic nevi (LCMN) has shown increased risk for development of melanoma. Here, we investigate whether Nodal expression can help identify the rare cases of LCMN that develop melanoma and shed light on why the majority of these patients do not. Immunohistochemistry (IHC) staining results show varying degree of Nodal expression in pediatric dysplastic nevi and LCMN. Moreover, median scores from Nodal IHC expression analysis were not significantly different between these two groups. Additionally, none of the LCMN patients in this study developed melanoma, regardless of Nodal IHC levels. Co-culture experiments revealed reduced tumor growth and lower levels of Nodal and its signaling molecules P-SMAD2 and P-ERK1/2 when melanoma cells were grown in vivo or in vitro with normal melanocytes. The same was observed in melanoma cells cultured with melanocyte conditioned media containing pigmented melanocyte derived melanosomes (MDM). Since MDM contain molecules capable of inactivating radical oxygen species, to investigate potential anti-oxidant effect of MDM on Nodal expression and signaling in melanoma, melanoma cells were treated with either N-acetyl-l-cysteine (NAC), a component of the anti-oxidant glutathione or synthetic melanin, which in addition to providing pigmentation can also exert free radical scavenging activity. Melanoma cells treated with NAC or synthetic melanin showed reduced levels of Nodal, P-SMAD2 and P-ERK1/2 compared to untreated melanoma cells. Thus, the potential role for Nodal in melanoma development in LCMN is less evident than in adult dysplastic nevi possibly due to melanocyte cross-talk in LCMN capable of offsetting or delaying the pro-melanoma effects of Nodal via anti-oxidant effects of MDM.

Dataset Information

Interferon-? Signaling in Melanocytes and Melanoma Cells Regulates Expression of CTLA-4.

Publications

Interferon-γ Signaling in Melanocytes and Melanoma Cells Regulates Expression of CTLA-4.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets