New players in melanoma micro environment

Melanoma originates in the epidermis and becomes metastatic after invasion into the dermis. Prior interactions between melanoma
cells and dermis are poorly studied. We have previously showed that melanoma cells directly affect the formation of the dermal tumour niche
by microRNA trafficking before invasion. Melanocytes, cells of melanoma origin, are specialized in releasing pigment vesicles,
termed melanosomes. In melanoma in situ, we found melanosome markers in distal fibroblasts before melanoma invasion. The
melanosomes carry microRNAs into primary fibroblasts triggering changes, including increased proliferation, migration and
pro-inflammatory gene expression, all known features of cancer-associated fibroblasts (CAFs). Here we show that these melanosome are up taken by endothelial cell and macrophages, leading to further shaping of the metastatic niche by enahcing angiogenesis and affecting the immune system.