Melanoma-derived exosomal miRNAs and keratinocyte-derived LL-37 define an epidermal–tumor arms race in melanoma

Melanoma progression involves dynamic interactions between tumor cells and the surrounding epidermal microenvironment. The cathelicidin antimicrobial peptide LL-37, expressed by keratinocytes, has been implicated in tumor-host defense; however, its transcriptomic impact on melanoma cells and its in vivo relevance remain incompletely characterized. Here, we performed bulk RNA sequencing of LL-37-treated A375 human melanoma cells in vitro and of tumor-bearing dorsal skin from K14CreCampf/f (cKO) and wild type mice (WT) subjected to topical imiquimod stimulation in vivo, to elucidate the transcriptomic landscape underlying LL-37-mediated suppression of melanoma progression.