Project description:Metabolic reprogramming, in which altered utilization of glucose and glutamine supports rapid growth, is a hallmark of most cancers. Mutations in the oncogenes KRAS and BRAF drive metabolic reprogramming through enhanced glucose uptake, but the broader impact of these mutations on pathways of carbon metabolism is unknown. Global shotgun proteomic analysis of isogenic DLD-1 and RKO colon cancer cell lines expressing mutant and wild type KRAS or BRAF, respectively, failed to identify significant differences (at least 2-fold) in metabolic protein abundance. However, a multiplexed parallel reaction monitoring (PRM) strategy targeting 73 metabolic proteins identified significant protein abundance increases of 1.25-twofold in glycolysis, the nonoxidative pentose phosphate pathway, glutamine metabolism, and the phosphoserine biosynthetic pathway in cells with KRAS G13D mutations or BRAF V600E mutations. These alterations corresponded to mutant KRAS and BRAF-dependent increases in glucose uptake and lactate production. Metabolic reprogramming and glucose conversion to lactate in RKO cells were proportional to levels of BRAF V600E protein. In DLD-1 cells, these effects were independent of the ratio of KRAS G13D to KRAS wild type protein. A study of 8 KRAS wild type and 8 KRAS mutant human colon tumors confirmed the association of increased expression of glycolytic and glutamine metabolic proteins with KRAS mutant status. Metabolic reprogramming is driven largely by modest (<2-fold) alterations in protein expression, which are not readily detected by the global profiling methods most commonly employed in proteomic studies. The results indicate the superiority of more precise, multiplexed, pathway-targeted analyses to study functional proteome systems. Data are available through MassIVE Accession MSV000079486 at ftp://MSV000079486@massive.ucsd.edu.
Project description:The genome-wide miRNA expression analysis was performed in clinical samples, comprising 15 BRAF-mutant and 15 non-KRAS/BRAF-mutant colorectal cancers by using a SurePrint G3 Human miRNA microarray. clinical samples, comprising 15 BRAF-mutant and 15 non-KRAS/BRAF-mutant colorectal cancers by using a SurePrint G3 Human miRNA microarray.
Project description:Goals of the study was to compare transcripional and phenotypic response of mouse intestinal organoid cultures to the KRAS(G12V) or BRAF(V600E)oncogenes.
Project description:The genome-wide miRNA expression analysis was performed in clinical samples, comprising 15 BRAF-mutant and 15 non-KRAS/BRAF-mutant colorectal cancers by using a SurePrint G3 Human miRNA microarray.
Project description:Despite advances in the detection and management of colorectal cancers, resistance to anti-cancer therapies remains a significant challenge. Activating mutations in KRAS and BRAF are frequently observed in colorectal cancers and have been associated with aggressive tumors and poor survival after chemotherapy. In the present study, we demonstrate that mutations in KRAS/BRAF alter the enhancer landscape of tumor cells, which leads to the resistance of the cornerstone colorectal cancer chemotherapeutic agent 5-fluorouracil (5-FU) through activation of transcription factor GATA1. Targeted inhibition of GATA1 reverses epigenetic changes in KRAS mutant cells and restores sensitivity to 5-FU. These results indicate a novel therapeutic opportunity for tailoring individualized therapy in human colorectal cancer.
Project description:Current treatments for KRAS-mutant colorectal cancers (CRCs) are often limited by cellular plasticity and rewiring responses. Here we describe a promising therapeutic strategy that simultaneously targets epigenetic and oncogenic signals. Specifically, we show that inhibitors of the histone methyltransferase, EZH2, synergize with various RAS pathway inhibitors and promote dramatic tumor regression in vivo. Together these agents cooperatively suppress WNT-driven transcription and drive CRCs into a more differentiated cell state by inducing the Groucho/TLE corepressor, TLE4, along with a network of WNT pathway inhibitors and intestinal differentiation proteins. However, these agents also induce the pro-apoptotic protein BMF, which subsequently kills these more differentiated cells. Accordingly, cell death can be prevented by activating β-catenin, blocking differentiation, or by ablating BMF expression. Collectively, these studies reveal a new therapeutic approach for treating KRAS-mutant CRCs and illustrate a critical convergence of EZH2 and RAS on oncogenic WNT signals, intestinal differentiation, and apoptosis.
Project description:Current treatments for KRAS-mutant colorectal cancers (CRCs) are often limited by cellular plasticity and rewiring responses. Here we describe a promising therapeutic strategy that simultaneously targets epigenetic and oncogenic signals. Specifically, we show that inhibitors of the histone methyltransferase, EZH2, synergize with various RAS pathway inhibitors and promote dramatic tumor regression in vivo. Together these agents cooperatively suppress WNT-driven transcription and drive CRCs into a more differentiated cell state by inducing the Groucho/TLE corepressor, TLE4, along with a network of WNT pathway inhibitors and intestinal differentiation proteins. However, these agents also induce the pro-apoptotic protein BMF, which subsequently kills these more differentiated cells. Accordingly, cell death can be prevented by activating β-catenin, blocking differentiation, or by ablating BMF expression. Collectively, these studies reveal a new therapeutic approach for treating KRAS-mutant CRCs and illustrate a critical convergence of EZH2 and RAS on oncogenic WNT signals, intestinal differentiation, and apoptosis.
Project description:Current treatments for KRAS-mutant colorectal cancers (CRCs) are often limited by cellular plasticity and rewiring responses. Here we describe a promising therapeutic strategy that simultaneously targets epigenetic and oncogenic signals. Specifically, we show that inhibitors of the histone methyltransferase, EZH2, synergize with various RAS pathway inhibitors and promote dramatic tumor regression in vivo. Together these agents cooperatively suppress WNT-driven transcription and drive CRCs into a more differentiated cell state by inducing the Groucho/TLE corepressor, TLE4, along with a network of WNT pathway inhibitors and intestinal differentiation proteins. However, these agents also induce the pro-apoptotic protein BMF, which subsequently kills these more differentiated cells. Accordingly, cell death can be prevented by activating β-catenin, blocking differentiation, or by ablating BMF expression. Collectively, these studies reveal a new therapeutic approach for treating KRAS-mutant CRCs and illustrate a critical convergence of EZH2 and RAS on oncogenic WNT signals, intestinal differentiation, and apoptosis.