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Simple Summary: BRAF is a serine/threonine kinase that is commonly mutated across cancers. The BRAF V600E mutation is targetable with kinase inhibitors; however, many patients eventually develop resistance. Recent evidence suggests that tumors harboring BRAF mutations may oxidize fatty acids for energy rather than utilizing aerobic glycolysis (the Warburg effect). Understanding the metabolism of cells harboring BRAF mutations may uncover targets to improve therapy response. We studied the effects of BRAF mutation and expression on metabolism. We found that cell expressing BRAF V600E were enriched with immunomodulatory lipids and have a metabolism that is distinct from cells expressing wild type BRAF. We also found that patients with melanoma who did not respond to BRAF-targeted therapy had plasma lipid profiles that were different from patients who responded to this therapy. Overall, our findings indicate that targeting lipid metabolism may be a potential alternative strategy to improve patient responses to BRAF-targeted therapies. There is increasing evidence that oxidative metabolism and fatty acids play an important role in BRAF-driven tumorigenesis, yet the effect of BRAF mutation and expression on metabolism is poorly understood. We examined how BRAF mutation and expression modulates metabolite abundance. Using the non-transformed NIH3T3 cell line, we generated cells that stably overexpressed BRAF V600E or BRAF WT. We found that cells expressing BRAF V600E were enriched with immunomodulatory lipids. Further, we found a unique transcriptional signature that was exclusive to BRAF V600E expression. We also report that BRAF V600E mutation promoted accumulation of long chain polyunsaturated fatty acids (PUFAs) and rewired metabolic flux for non-Warburg behavior. This cancer promoting mutation further induced the formation of tunneling nanotube (TNT)-like protrusions in NIH3T3 cells that preferentially accumulated lipid droplets. In the plasma of melanoma patients harboring the BRAF V600E mutation, levels of lysophosphatidic acid, sphingomyelin, and long chain fatty acids were significantly increased in the cohort of patients that did not respond to BRAF inhibitor therapy. Our findings show BRAF V600 status plays an important role in regulating immunomodulatory lipid profiles and lipid trafficking, which may inform future therapy across cancers. [ABSTRACT FROM AUTHOR]

Simple Summary: In the last two decades, new molecules, named microRNAs, have been identified. Impairment of microRNA function can lead to the development of diseases such as cancer; therefore, analyzing microRNAs expression, may help to explain the development of diseases. Moreover, these molecules can be obtained easily from blood, with little discomfort to the patient, and this may help to develop them as substances that could help to diagnose diseases and determine response to treatment. Here, we studied how microRNAs are involved in a rare clonal hematological malignancy named Erdheim–Chester disease (ECD). We found a differential expression microRNA signature between ECD patients and healthy controls. Our analysis suggests that reduced expression of microRNAs in ECD results in upregulation of target genes that participate in cell survival signaling and inflammation. This study expands our knowledge of the molecular basis of ECD and may enable improved treatment for affected patients. The pathogenesis of histiocytic neoplasms is driven by mutations activating the MAPK/ERK pathway, but little is known about the transcriptional and post-transcriptional alterations involved in these neoplasms. We analyzed microRNA (miRNA) expression in plasma samples and tissue biopsies of Erdheim–Chester disease (ECD) and Langerhans cell histiocytosis (LCH) patients. In silico analysis revealed a potential role of miRNAs in regulating gene expression in these neoplasms as compared with healthy controls (HC). NanoString analysis revealed 101 differentially expressed plasma miRNAs in 16 ECD patients as compared with 11 HC, 95% of which were downregulated. MiRNAs-15a-5p, -15b-5p, -21-5p, -107, -221-3p, -320e, -630, and let-7 family miRNAs were further evaluated by qRT-PCR in an extended cohort of 32 ECD patients, seven LCH and 15 HC. Six miRNAs (let-7a, let-7c, miR-15a-5p, miR-15b-5p, miR-107 and miR-630) were highly expressed in LCH plasma and tissue samples as compared with ECD. Pathway enrichment analysis indicated the miRNA contribution to inflammatory and pro-survival signaling pathways. Moreover, the let-7 family members were downregulated in untreated ECD patients as compared with HC, while treatment with MAPK/ERK signaling inhibitors for 16 weeks resulted in their upregulation, which was in parallel with the radiologic response seen by PET-CT. The study highlights the potential contribution of miRNA to the inflammatory and neoplastic characteristics of ECD and LCH. [ABSTRACT FROM AUTHOR]

Pancreatic ductal adenocarcinoma (PDAC) is a leading cause of cancer-related deaths in the USA. Desmoplasia and inflammation are two major hallmarks of PDAC. Desmoplasia, composed of extracellular matrix (ECM), cancer-associated fibroblasts (CAFs), and infiltrating immune and endothelial cells, acts as a biophysical barrier to hinder chemotherapy and actively contributes to tumor progression and metastasis. CAFs represent a multifunctional subset of PDAC microenvironment and contribute to tumor initiation and progression through ECM deposition and remodeling, as well as the secretion of paracrine factors. Attempts to resolve desmoplasia by targeting CAFs can render an adverse outcome, which is likely due to CAFs heterogeneity. Recent reports describe subsets of CAFs that assume more secretory functions, in addition to the typical myofibroblast phenotype. Here, we review the literature and describe the relationship between CAFs and inflammation and the role of the secretory-CAFs in PDAC. [ABSTRACT FROM AUTHOR]