Project description:Epithelial-mesenchymal transition (EMT), a switch of polarized epithelial cells to a migratory, fibroblastoid phenotype, is considered a key process driving tumor cell invasiveness and metastasis. Using breast cancer cell lines as a model system, we sought to discover gene-expression signatures of EMT with clinical and mechanistic relevance. A supervised comparison of epithelial and mesenchymal breast cancer lines defined a 200-gene EMT signature that was prognostic across multiple breast cancer cohorts. Immunostaining of LYN, a top-ranked EMT signature gene and Src-family tyrosine kinase, was associated with significantly shorter overall survival (P=0.02), and correlated with the basal-like (“triple-negative”) phenotype. In mesenchymal breast cancer lines, RNAi-mediated knockdown of LYN inhibited cell migration and invasion, but not proliferation. Dasatinib, a dual-specificity tyrosine kinase inhibitor, also blocked invasion (but not proliferation) at nanomolar concentrations that inhibit LYN kinase activity, suggesting that LYN is a likely target and invasion a relevant endpoint for dasatinib therapy. Our findings define a prognostically-relevant EMT signature in breast cancer, and identify LYN as a mediator of invasion and possible new therapeutic target (and theranostic marker for dasatinib response), with particular relevance to clinically-aggressive basal-like breast cancer. Cell Line: cell line(epithelial-like/fibroblast-like/normal breast fibroblasts) Keywords: Logical Set Set of arrays organized by shared biological context, such as organism, tumors types, processes, etc. HEEBO oligonucleotide microarrays from the Stanford Functional Genomics Facility were used to perform gene expression profiling of 20 human breast cell lines, in comparison to a universal RNA reference. Expression data were analyzed by Significance Analysis of Microarrays to identify a 200-gene signature characteristic of EMT.
Project description:Epithelial-mesenchymal transition (EMT), a switch of polarized epithelial cells to a migratory, fibroblastoid phenotype, is considered a key process driving tumor cell invasiveness and metastasis. Using breast cancer cell lines as a model system, we sought to discover gene-expression signatures of EMT with clinical and mechanistic relevance. A supervised comparison of epithelial and mesenchymal breast cancer lines defined a 200-gene EMT signature that was prognostic across multiple breast cancer cohorts. Immunostaining of LYN, a top-ranked EMT signature gene and Src-family tyrosine kinase, was associated with significantly shorter overall survival (P=0.02), and correlated with the basal-like (“triple-negative”) phenotype. In mesenchymal breast cancer lines, RNAi-mediated knockdown of LYN inhibited cell migration and invasion, but not proliferation. Dasatinib, a dual-specificity tyrosine kinase inhibitor, also blocked invasion (but not proliferation) at nanomolar concentrations that inhibit LYN kinase activity, suggesting that LYN is a likely target and invasion a relevant endpoint for dasatinib therapy. Our findings define a prognostically-relevant EMT signature in breast cancer, and identify LYN as a mediator of invasion and possible new therapeutic target (and theranostic marker for dasatinib response), with particular relevance to clinically-aggressive basal-like breast cancer. Cell Line: cell line(epithelial-like/fibroblast-like/normal breast fibroblasts) Keywords: Logical Set
Project description:Pharmacological levels of Withaferin A (Withania somnifera) trigger clinically relevant anticancer effects specific to triple negative breast cancer cells
Project description:Breast tumors are highly heterogeneous and for many molecular subtypes no targeted therapies are available. These include breast cancers that display hallmarks of epithelial to mesenchymal transition (EMT), a process related to metastasis and enriched in triple negative breast cancers (TNBCs). To determine whether this EMT cellular state could be therapeutically exploited, we performed a large-scale chemical genetic screen. We identified a group of structurally related compounds, including the clinically advanced drug PKC412 (midostaurin), that targeted post-EMT breast cancer cells. PKC412 induced apoptosis specifically in basal-like TNBC cells and inhibited tumor growth in vivo. Structure activity relationship (SAR) studies, chemical proteomics, and computational modeling identified the kinase SYK as a critical PKC412 target. Specific SYK inhibitors and PKC412 displayed a similar profile across a large panel of breast cancer cell lines, indicating a shared mode of action. Phosphoproteomics analysis revealed that SYK activates STAT3, and chemical or genetic inhibition of STAT3 resulted in cell death in basal-like breast cancer cells. This non-oncogene addiction of basal-like breast cancer cells to SYK suggests that chemical SYK inhibition may be beneficial for a specific subset of triple negative breast cancer patients.