Project description:Tumor heterogeneity drives disease progression, treatment resistance, and patient relapse, yet remains largely under-explored in invasion and metastasis. Here, we investigated heterogeneity within collective cancer invasion by integrating DNA methylation and gene expression analysis in rare purified lung cancer leader and follower cells. Our results showed global DNA methylation rewiring in leader cells and revealed the filopodial motor MYO10 as a critical gene at the intersection of epigenetic heterogeneity and 3D collective invasion. We further identified JAG1 signaling as a novel upstream activator of MYO10 expression in leader cells. Using live cell imaging, we discovered that MYO10 drives filopodial persistence necessary for micropatterning extracellular fibronectin into linear tracks at the edge of 3D collective invasion exclusively in leaders. Our data fit a model where epigenetic heterogeneity and JAG1/Notch signaling jointly drive collective cancer invasion through MYO10 upregulation in epigenetically permissive leader cells, which induces filopodia dynamics necessary for linearized fibronectin micropatterning.
Project description:Inter-patient and intra-tumoral heterogeneity complicate the identification of predictive biomarkers and effective treatments for basal triple negative breast cancer (b-TNBC). Invasion is the initiating event in metastasis and can occur by both collective and single-cell mechanisms. We cultured primary organoids from a b-TNBC genetically engineered mouse model in 3D collagen gels to characterize their invasive behavior. We observed that organoids from the same tumor presented different phenotypes that we classified as non-invasive, collective and disseminative. To identify molecular regulators driving these invasive phenotypes, we developed a workflow to isolate individual organoids from the collagen gels based on invasive morphology and perform RNA sequencing. We next tested the requirement of differentially regulated genes for invasion using shRNA knock-down. Strikingly, KRAS was required for both collective and disseminative phenotypes. We then performed a drug screen targeting signaling nodes upstream and downstream of KRAS. We found that inhibition of EGFR, MAPK/ERK, or PI3K/AKT signaling reduced invasion. Of these, ERK inhibition was striking for its ability to potently inhibit collective invasion and dissemination. We conclude that different cancer cells in the same b-TNBC tumor can express different metastatic molecular programs and identified KRAS and ERK as essential regulators of collective and single cell dissemination.
Project description:It has been suggested that breast cancers are driven and maintained by a cellular subpopulation with stem cell properties. These breast cancer stem cells (BCSCs) mediate metastasis and by virtue of their resistance to radiation and chemotherapy, contribute to relapse. Although several BCSC markers have been described, it is unclear whether these markers identify the same or independent BCSC populations. Based on established breast cancer cell lines, as well as primary tumor samples and xenografts, we show that BCSCs exist in distinct mesenchymal-like (epithelial-mesenchymal transition, EMT) and epithelial-like (mesenchymal-epithelial transition, MET) states characterized by expression of distinct markers, proliferative capacity and invasive characteristics. The gene expression profiles of mesenchymal-like and epithelial-like BCSCs are remarkably similar across the different molecular subtypes of breast cancer and resemble those of distinct basal and luminal stem cells found in the normal breast. We propose that the plasticity of BCSCs allowing them to transition between EMT- and MET-like states endows these cells with the capacity for tissue invasion, dissemination and growth at metastatic sites. Breast cancer cells from patient were sorted using flow cytometry to select for cells that were ALDH+. Gene expression profiles of these cells were compared with profiles of ALDH- cells.
Project description:It has been suggested that breast cancers are driven and maintained by a cellular subpopulation with stem cell properties. These breast cancer stem cells (BCSCs) mediate metastasis and by virtue of their resistance to radiation and chemotherapy, contribute to relapse. Although several BCSC markers have been described, it is unclear whether these markers identify the same or independent BCSC populations. Based on established breast cancer cell lines, as well as primary tumor xenografts, we show that BCSCs exist in distinct mesenchymal-like (epithelial-mesenchymal transition, EMT) and epithelial-like (mesenchymal-epithelial transition, MET) states characterized by expression of distinct markers, proliferative capacity and invasive characteristics. The gene expression profiles of mesenchymal-like and epithelial-like BCSCs are remarkably similar across the different molecular subtypes of breast cancer and resemble those of distinct basal and luminal stem cells found in the normal breast. We propose that the plasticity of BCSCs allowing them to transition between EMT- and MET-like states endows these cells with the capacity for tissue invasion, dissemination and growth at metastatic sites. Breast cancer cell lines, primary xenografts and normal breast cells from patient were sorted using flow cytometry to select for cells that were CD24-,CD44+ and ALDH+. Gene expression profiles of CD24-CD44+ cells were compared with non-CD24-CD44+ cells. Gene expression profiles of ALDH+ cells were compared with ALDH- cells.
Project description:Triple-negative breast cancer is a highly aggressive tumor subtype that lacks effective therapeutic targets. Here, we show that ELK3 is overexpressed in a subset of breast cancers, in particular basal-like and normal-like/claudin-low cell lines. Suppression of ELK3 in MDA-MB-231 cells led to transdifferentiation from an invasive mesenchymal phenotype to a non-invasive epithelial phenotype both in vitro and in vivo. Suppression of ELK3 results in the extensive changes in genome expression profiles. Among these, GATA3, a master suppressor of metastasis, was epigenetically activated and we found that suppression of GATA3 led to the restoration of migration and invasion. These results suggest that the ELK3-GATA3 axis is a major pathway that promotes metastasis of MDA-MB-231 cells. Retrovirus expressing shRNA of ELK3 was transduced into MDA-MB-231 cell line and stable cell line of which ELK3 is suppressed more than 50% was selected by the drug selection (Puromycin).
Project description:A distinct highly invasive subpopulation was identified in breast cancer cell lines. The molecular characteristics of these cells was investigated, revealing a set of genes whose high expression confers the ability to invade. Total RNA isolated from the invasive subpopulation from 2 cells lines was compared to total RNA isolated from 2 noninvasive populations.
Project description:Collective cell migration is one of the principal modes for cancer cell movements. However, the triggering event for collective migration and its clinical significance is unclear. Here, we found that Snail, a major inducer of epithelial-mesenchymal transition (EMT), is critical for orchestrating collective migration in squamous cell carcinoma (SCC). To invstigate how Snail contribute to collective migration and invasion, we used microarrays to identify the global gene alterations regulated by Snail in SCC cells.
Project description:It has been suggested that breast cancers are driven and maintained by a cellular subpopulation with stem cell properties. These breast cancer stem cells (BCSCs) mediate metastasis and by virtue of their resistance to radiation and chemotherapy, contribute to relapse. Although several BCSC markers have been described, it is unclear whether these markers identify the same or independent BCSC populations. Based on established breast cancer cell lines, as well as primary tumor samples and xenografts, we show that BCSCs exist in distinct mesenchymal-like (epithelial-mesenchymal transition, EMT) and epithelial-like (mesenchymal-epithelial transition, MET) states characterized by expression of distinct markers, proliferative capacity and invasive characteristics. The gene expression profiles of mesenchymal-like and epithelial-like BCSCs are remarkably similar across the different molecular subtypes of breast cancer and resemble those of distinct basal and luminal stem cells found in the normal breast. We propose that the plasticity of BCSCs allowing them to transition between EMT- and MET-like states endows these cells with the capacity for tissue invasion, dissemination and growth at metastatic sites.