Project description:Colon cancer cell lines with partial sensitivity to the BRAF inhibitor PLX4720 were grown in increasing concentration of the drug to develop acquired resistance. Gene expression was performed for comparison of the resistant clones to the parental lines. Colon cancer cell lines with partial sensitivity to the BRAF inhibitor PLX4720 were grown in increasing concentration of the drug to develop acquired resistance. Gene expression was performed for comparison of the resistant clones to the parental lines.
Project description:Despite the connection to distinct mucus-containing colorectal cancer (CRC) histological subtypes, the role of secretory cells, including goblet and enteroendocrine (EEC) cells, in CRC progression has been underexplored. Analysis of TCGA and single cell RNA sequencing data demonstrates that multiple secretory progenitor populations are enriched in BRAF-mutant CRC patient tumors and cell lines. Enrichment of EEC progenitors in BRAF-mutant CRC is maintained by DNA methylation and silencing of NEUROD1, a key gene required for differentiation of EECs. Mechanistically, secretory cells and the factors they secrete, such as Trefoil factor 3, are shown to promote colony formation and activation of cell survival pathways in the entire cell population. We further identify LSD1 as a critical regulator of secretory cell specification in vitro and in a colon orthotopic xenograft model, where LSD1 loss reduces tumor growth and metastasis. This work establishes EEC progenitors, in addition to goblet cells, as targetable populations in BRAF-mutant CRC and identifies LSD1 as a therapeutic target in secretory lineage-containing CRC.
Project description:Colon cancer cell lines with partial sensitivity to the BRAF inhibitor PLX4720 were grown in increasing concentration of the drug to develop acquired resistance. Gene expression was performed for comparison of the resistant clones to the parental lines.
Project description:Here we describe the use of multiple forward genetic screens executed in parallel to identify those genes, and their cognate pathways, that when overexpressed, silenced or mutated confer resistance in BRAF mutant colon cancer to a BRAF/MEK/EGFR inhibitor combination. We demonstrate that this resistance landscape is finite, relatively constrained to a small number of pathways and that it is possible to exploit the evolutionary dynamics that underpins the clonal expansion of drug resistant cells therapeutically.
