229P - Investigation of the effects of long-noncoding RNA NRAV on interferon response in melanoma

Background

The role of long noncoding RNAs (lncRNAs) expressed by tumor cells in controlling antitumor immune responses remains unclear. This project focuses on melanoma, a highly aggressive skin cancer, to investigate the roles of a recently identified and understudied lncRNA called NRAV (Negative Regulator of Antiviral Response) in regulating the interferon response in cancer cells. NRAV has been shown to epigenetically inhibit interferon-stimulated genes (ISG). Our strong unpublished preliminary data indicating that NRAV expression is significantly higher in human melanoma cells compared to various immune cells. High NRAV expression negatively impacts survival, particularly in tumors rich in immune cells. Cancers with high NRAV expression largely lack the IFNγ (Interferon gamma) response gene signature. In line with these data, our project's focus is on investigating the unknown lncRNA called NRAV in melanoma tumor immunity.

Methods

In the current phase of the project, melanoma cell lines with silenced and over-expressed NRAV have been created using shRNA and NRAV gene containing vectors. Vectors are introduced into the cell lines via retroviral transduction. To investigate the effects of Type I and type II interferons, the cell lines were treated with IFNα and IFNγ in time-dependent manner. Total RNA was isolated from the cells, and transcript levels in response to IFN were measured using qRT-PCR.

Results

NRAV silencing under IFNγ stimulation led to a significant increase in ISGs transcript levels as expected. In concurrent experiments with IFNα, ISGs transcript levels either did not change or showed non-significant variations.

Conclusions

All these findings suggest that NRAV might play a more inhibitory role in IFNγ response. High expression level of NRAV in melanoma is probably related to immune escape mechanism through IFNγ response. NRAV's role in melanoma and tumor immunity will be clarified through future experiments focused on proliferation, localization, and identifying protein partners. This will help for identifying new cellular targets for therapeutics in cancer. Understanding lncRNAs and the pathways they control contributes to the development of new advanced therapeutic approaches in cancer treatment.

Legal entity responsible for the study

Izmir Institute of Technology.

Funding

The Scientific and Technological Research Council of Türkiye (TÜBİTAK).

Disclosure

K.Z. Durmus: Financial Interests, Institutional, Research Funding: The Scientific and Technological Research Council of Türkiye (TÜBİTAK). A. Ekiz: Financial Interests, Institutional, Research Funding, TUBITAK is a government foundation; The Scientific and Technological Research Council of Türkiye (TÜBİTAK).