Metastatic
melanoma is a deadly
malignancy with poor outcomes historically. Immuno-oncology (IO) agents, targeting
immune checkpoint molecules such as cytotoxic T-lymphocyte associated protein-4 (CTLA-4) and programmed cell death-1 (PD-1), have revolutionized
melanoma treatment and outcomes, achieving significant response rates and remarkable long-term survival. Despite these vast improvements, roughly half of
melanoma patients do not achieve long-term clinical benefit from IO
therapies and there is an urgent need to understand and mitigate mechanisms of resistance.
MicroRNAs are key post-transcriptional regulators of gene expression that regulate many aspects of
cancer biology, including immune evasion. We used network analysis to define two core
microRNA-
mRNA networks in
melanoma tissues and cell lines corresponding to 'MITF-low' and '
Keratin' transcriptomic subsets of
melanoma. We then evaluated expression of these core
microRNAs in pre-PD-1-inhibitor-treated
melanoma patients and observed that higher expression of miR-100-5p and miR-125b-5p were associated with significantly improved overall survival. These findings suggest that miR-100-5p and 125b-5p are potential markers of response to
PD-1 inhibitors, and further evaluation of these
microRNA-
mRNA interactions may yield further insight into
melanoma resistance to
PD-1 inhibitors.