Project description:Among the myriad tumors analyzed to date, cutaneous malignant melanomas bear some of the highest mutational burdens. Thus, it is somewhat surprising that oncogene exclusion between is so pronounced in melanomas where there is only a single melanoma out of 366 sequenced specimens which harbors concurrent BRAF(V600E/M) and NRAS(G13R) mutations (TCGA-ES-A2NC Sample; WWW.bioportal.org), In this senario some NRAS and BRAF mutations co-expressing cells show slow growth phenotypes by under study mechanism. We used Affymetrix GeneChip Expression Arrays to detail the global programme of gene expression underlying oncogenic exclusion and identified distinct classes of up and down-regulated genes during this process.
Project description:Extracellular vesicles (EVs) are a key form of cell-to-cell communication. Here we reveal a new mode of communication involving the large EVs, melanosomes. Unlike small EVsexosomes, which are dissolved in the receiver cell, melanosomes stay intact within them, gain a unique protein signature, and can then be further transferred to another cell, a state we term “second-hand EVs”. We found that melanoma-secreted melanosomes uptaken by and then released from epidermal keratinocytes or dermal fibroblasts can be further engulfed by resident macrophages. The respective consequence for macrophages is polarization into pro-tumor or pro-immune-cell-infiltration phenotypes. Fibroblasts load melanosomes with AKT1, which induces VEGF secretion from macrophages in an mTOR-dependent manner, promoting angiogenesis and metastasis in-vivo. In melanoma patients, macrophages co-localized with AKT1, were correlated with disease aggressiveness, and immunotherapy non-responders were enriched in macrophages containing melanosome markers. Thus, the network of interactions via second-hand EVs helps form the metastatic niche. Since macrophage heterogeneity is pivotal in advancement of cancer, our data suggest an opportunity to halt melanoma progression by blocking the melanosome cues of macrophage diversification.
Project description:Extracellular vesicles (EVs) are a key form of cell-to-cell communication. Here we reveal a new mode of communication involving the large EVs, melanosomes. Unlike small EVs, which are dissolved in the receiver cell, melanosomes stay intact within them, gain a unique protein signature, and can then be further transferred to another cell, a state we term “second-hand EVs”. We found that melanoma-secreted melanosomes uptaken by and then released from epidermal keratinocytes or dermal fibroblasts can be further engulfed by resident macrophages. The respective consequence for macrophages is polarization into pro-tumor or pro-immune-cell-infiltration phenotypes. Fibroblasts load melanosomes with AKT1, which induces VEGF secretion from macrophages in an mTOR-dependent manner, promoting angiogenesis and metastasis in-vivo. In melanoma patients, macrophages co-localized with AKT1, were correlated with disease aggressiveness, and immunotherapy non-responders were enriched in macrophages containing melanosome markers. Thus, the network of interactions via second-hand EVs helps form the metastatic niche. Since macrophage heterogeneity is pivotal in advancement of cancer, our data suggest an opportunity to halt melanoma progression by blocking the melanosome cues of macrophage diversification.
Project description:Molecular function of BMPs in metastatic melanoma progression is undefined. The goal of this study is to identify BMP6-activated gene signaturs associated with metastatic progresses in human cutaneous melanoma. Transcriptome profiles (RNA-seq) of three melanoma cell lines (WM1341D, WM983B, and 1205Lu) stably expressing BMP6 and coressponding control cells were generated by deep sequencing using illumona HiSeq and mapped more than 30 million sequencing reads per sample to the human genome (build Hg19). Gene signatures down-regulated by BMP6 are mostly associated with extracellular matrix organization and growth factor binding, suggesting a metastasis-suppressive role of BMP6 in melanoma.
Project description:Identify miRNAs enriched or overexpressed in melanoma-derived exosomes compared to melanoma cells. We analyzed the 2,578 human miRNAs located in the array according to two ways. The first one identified the differentially expressed miRNAs between melanoma-derived exosomes and their parent cells. In this way, we found 198 miRNAs up-regulated in melanoma cell lines compared to their exosomes and 206 miRNAs up-regulated in exosomes compared to their donor cells. The second way of analysis identifies the most expressed miRNAs in the melanoma-derived exosomes without assumption about their expression in parent cells. We defined two criteria; the first one is a RMA (Robust Multi-Array Average, a good alternative to gene expression value) above 5, corresponding to the mean expression level of the array and a SD ≤ 0.2 between all samples to discover miRNAs expressed uniformly between melanoma-derived exosomes M113 and M117. We identified 44 miRNAs under these criteria.