Project description:Despite recent therapeutic progress, advanced melanoma remains lethal for many patients. The composition of the immune tumor microenvironment (TME) has decisive impacts on disease outcome and therapy response. High dimensional analyses of patient samples provide insight on the composition and heterogeneity of the immune TME. Macrophages are known for their cancer-supportive role, but the underlying mechanisms are incompletely understood, and experimental in vivo systems are needed to test the functional properties of these cells. We characterize a humanized mouse model, reconstituted with a human immune system and a human melanoma, in which: (1) human macrophages support metastatic spread of the tumor; and (2) tumor-infiltrating macrophages have a specific transcriptional signature that faithfully represents the transcriptome of macrophages from patient melanoma samples and is associated with shorter survival. This model complements patient sample analyses, enabling the elucidation of fundamental principles in melanoma biology, and the development and evaluation of candidate therapies.
Project description:Therapeutic interventions modulating immune function at the tumor site could improve outcomes in cancer. Here we analyzed metastatic melanoma; a tumor type highly responsive to T-cell based therapies, and found that the tumor-infiltrating T cells are localized closely to CD14+ monocytes/macrophages rather than to melanoma cells. Using customized immunofluorescence-guided laser capture micro-dissection, we analyzed transcriptome of CD3+ T cells, CD14+ monocytes/macrophages and melanoma cells in non-dissociated tissue. CD14+ cells localized in tumors beds displayed specific transcriptional signature distinct from CD14+ cells that were localized in tumor stroma. When applied to TCGA cohorts, the gene module of stromal macrophages distinguished patients with significantly prolonged survival in cutaneous melanoma and as well as other cancers including uveal melanoma, bladder urothelial carcinoma and lower grade glioma. This gene module contained CD14; Ly75, a gene linked with antigen capture and regulation of tolerance and immunity; and CD2; altogether a signature of monocyte-derived dendritic cells (DCs). Thus, stromal CD14+ cell signature represents a novel candidate biomarker and targeted reprogramming of stromal macrophages to acquire DC function might offer a therapeutic opportunity for metastatic cancer.
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:Melanoma cell lines were genotyped to evaluate copy number differences between nodular melanoma (NM) and superficial spreading melanoma (SSM). Cell lines were also evaluated for copy number alterations in the SKP2/p27 axis. Affymetrix SNP arrays were performed according to manufacturer's instructions using DNA extracted from 18 melanoma cell lines and 4 melanocyte controls. Affymetrix SNP6.0 Array data for melanoma cell lines Copy number analysis of Affymetrix SNP 6.0 arrays was performed on 18 melanoma cell lines including 2 primary superficial spreading melanoma, 2 primary nodular melanoma, 2 metastatic nodular melanoma, and 12 metastatic cell lines. Four melanocyte control lines were also evaluated including 2 immortalized melanocyte cell lines (Hermes 1 and 2B) and 2 normal melanocyte lines cultured from neonatal foreskin (HEM-N and HEM-LP) that were used to construct the baseline for copy number analysis.
Project description:Cerebral metastases occur in a majority of metastatic melanoma patients and are a major cause of mortality. Despite this, there is a poor understanding of the molecules/pathways that lead to the brain-metastatic phenotype. Studies designed to address this deficiency and test novel therapeutic approaches have until recently been slowed by an absence of preclinical models of spontaneous CNS metastatic melanoma disease. To address this, we isolated two variants of the human melanoma cell line WM239 (named 131/4-5B1 and 131/4-5B2) which can metastasize spontaneously to brain parenchyma from an orthotopic primary transplant. We have performed gene expression profiling on both brain metastatic cell lines (131/4-5B1 and 131/4-5B2) and compared to the poorly metastatic parental cell line WM239A and a derived highly metastatic variant 113/6-4L in order to examine the mechanisms that influence the progression of malignant melanoma to a brain-metastatic phenotype. Two-condition experiment, brain metastatic cell lines (131/4-5B1 and 131/4-5B2) and compared to the poorly metastatic parental cell line WM239A and a derived highly metastatic variant 113/6-4L. Biological replicates: 4 independently grown and harvested cell line passages. Two technical replicate per condition (including dye swap).
Project description:Melanoma incidence and mortality rates are historically higher for men than women. Although emerging studies have highlighted tumorigenic roles for the male sex hormone androgen and its receptor (AR) in melanoma, cellular and molecular mechanisms underlying these sex-associated discrepancies are poorly defined. Here, we delineate a previously undisclosed mechanism by which androgen-activated AR transcriptionally upregulates fucosyltransferase 4 (FUT4) expression, which drives melanoma invasiveness by interfering with adherens junctions (AJs). Global phosphoproteomic and fucoproteomic profiling, coupled with in vitro and in vivo functional validation, further reveals that AR-induced FUT4 fucosylates L1 cell adhesion molecule (L1CAM), which is required for FUT4-increased metastatic capacity. Tumor microarray and gene expression analyses demonstrate that AR-FUT4-L1CAM-AJs signaling correlates with pathological staging in melanoma patients. By delineating key androgen-triggered signaling that enhances metastatic aggressiveness, our findings help to explain sex-associated clinical outcome disparities and highlight AR/FUT4 and its effectors as potential prognostic biomarkers and therapeutic targets in melanoma.
Project description:Melanoma incidence and mortality rates are historically higher for men than women. Although emerging studies have highlighted tumorigenic roles for the male sex hormone androgen and its receptor (AR) in melanoma, cellular and molecular mechanisms underlying these sex-associated discrepancies are poorly defined. Here, we delineate a previously undisclosed mechanism by which androgen-activated AR transcriptionally upregulates fucosyltransferase 4 (FUT4) expression, which drives melanoma invasiveness by interfering with adherens junctions (AJs). Global phosphoproteomic and fucoproteomic profiling, coupled with in vitro and in vivo functional validation, further reveals that AR-induced FUT4 fucosylates L1 cell adhesion molecule (L1CAM), which is required for FUT4-increased metastatic capacity. Tumor microarray and gene expression analyses demonstrate that AR-FUT4-L1CAM-AJs signaling correlates with pathological staging in melanoma patients. By delineating key androgen-triggered signaling that enhances metastatic aggressiveness, our findings help to explain sex-associated clinical outcome disparities and highlight AR/FUT4 and its effectors as potential prognostic biomarkers and therapeutic targets in melanoma.