[HTML][HTML] MITF and c-Jun antagonism interconnects melanoma dedifferentiation with pro-inflammatory cytokine responsiveness and myeloid cell recruitment

S Riesenberg, A Groetchen, R Siddaway, T Bald… - Nature …, 2015 - nature.com
S Riesenberg, A Groetchen, R Siddaway, T Bald, J Reinhardt, D Smorra, J Kohlmeyer…
Nature communications, 2015nature.com
Inflammation promotes phenotypic plasticity in melanoma, a source of non-genetic
heterogeneity, but the molecular framework is poorly understood. Here we use functional
genomic approaches and identify a reciprocal antagonism between the melanocyte lineage
transcription factor MITF and c-Jun, which interconnects inflammation-induced
dedifferentiation with pro-inflammatory cytokine responsiveness of melanoma cells
favouring myeloid cell recruitment. We show that pro-inflammatory cytokines such as TNF-α …
Abstract
Inflammation promotes phenotypic plasticity in melanoma, a source of non-genetic heterogeneity, but the molecular framework is poorly understood. Here we use functional genomic approaches and identify a reciprocal antagonism between the melanocyte lineage transcription factor MITF and c-Jun, which interconnects inflammation-induced dedifferentiation with pro-inflammatory cytokine responsiveness of melanoma cells favouring myeloid cell recruitment. We show that pro-inflammatory cytokines such as TNF-α instigate gradual suppression of MITF expression through c-Jun. MITF itself binds to the c-Jun regulatory genomic region and its reduction increases c-Jun expression that in turn amplifies TNF-stimulated cytokine expression with further MITF suppression. This feed-forward mechanism turns poor peak-like transcriptional responses to TNF-α into progressive and persistent cytokine and chemokine induction. Consistently, inflammatory MITFlow/c-Junhigh syngeneic mouse melanomas recruit myeloid immune cells into the tumour microenvironment as recapitulated by their human counterparts. Our study suggests myeloid cell-directed therapies may be useful for MITFlow/c-Junhigh melanomas to counteract their growth-promoting and immunosuppressive functions.
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