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:This study explores the effects of KRAS and BRAF mutations on the heterogeneity, distribution, and uptake of extracellular vesicles (EVs), with a focus on their role in cancer biology and therapeutic potential. Nine cancer cell lines, including colorectal (Caco-2, HT29, WiDr, HCT116, LoVo) and lung cancer (H292, H1703, A549, H358), were selected based on KRAS and BRAF mutation status. EVs were isolated and characterized by TEM, Western blotting, and NTA. Proteomic analysis revealed that KRAS and BRAF mutant EVs were enriched in specific proteins, such as CD44 and LSR in KRAS mutations, and ITGB4 and CSPG4 in BRAF mutations. EV internalization was influenced by endocytosis and macropinocytosis, with competitive inhibition experiments showing the involvement of hyaluronic acid for CD44-mediated uptake and chondroitin sulfate for CSPG4. Finally, Doxorubicin-loaded KRAS-mutant EVs effectively delivered the drug to the nucleus, escaping lysosomal degradation. These findings suggest mutation-specific differences in EV biology and highlight their potential as targeted drug delivery vehicles in cancer therapy.
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:Oncogenic KRAS mutations are prevalent in colorectal cancer (CRC) and are associated with poor prognosis and resistance to therapy. There is a substantial diversity of KRAS mutant alleles observed in CRC. Emerging clinical and experimental analysis of common KRAS mutations suggest that each mutation differently influences the clinical properties of a disease and response to therapy. Although there is some evidence to suggest biological differences between mutant KRAS alleles, these are yet to be fully elucidated. One approach to study allelic variation involves the use of isogenic cell lines that express different endogenous Kras mutants. Here, we generated Kras isogenic Apc-/- mouse colon epithelial cell lines using CRISPR-driven genome editing by altering the original G12D Kras allele to G12V, G12R, or G13D. We utilized these cell lines to perform transcriptomic and proteomic analysis to compare different signaling properties between these mutants. Both screens indicate significant differences in pathways relating to cholesterol and lipid regulation that we validated with targeted metabolomic measurements and isotope tracing. We found that these processes are upregulated in G12V lines through increased expression of nuclear SREBP1 and higher activation of mTORC1. G12V cells showed higher expression of ACSS2 and ACSS2 inhibition sensitized G12V cells to MEK inhibition. Finally, we found that ACSS2 plays a crucial role early in the development of G12V mutant tumors, in contrast to G12D mutant tumors. These observations highlight differences between KRAS mutant cell lines in their signaling properties. Further exploration of these pathways may prove to be valuable for understanding how specific KRAS mutants function, and identification of novel therapeutic opportunities in CRC.
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.