Project description:Given the very substantial heterogeneity of most human cancers, it is likely that most cancer therapeutics will be active in only a small fraction of any population of patients. As such, the development of new therapeutics, coupled with methods to match a therapy with the individual patient, will be critical to achieving significant gains in disease outcome. One such opportunity is the use of expression signatures to identify key oncogenic phenotypes that can serve not only as biomarkers but also as a means of identifying therapeutic compounds that might specifically target these phenotypes. Given the potential importance of targeting tumors exhibiting a stem-like phenotype, we have developed an expression signature that reflects common biological aspects of various stem-like characteristics. The Consensus Stemness Ranking (CSR) signature is upregulated in cancer stem cell enriched samples, at advanced tumor stages and is associated with poor prognosis in multiple cancer types. Using two independent computational approaches we utilized the CSR signature to identify clinically useful compounds that could target the CSR phenotype. In vitro assays confirmed selectivity of several predicted compounds including topoisomerase inhibitors and resveratrol towards breast cancer cell lines that exhibit a high-CSR phenotype. Importantly, the CSR signature could predict clinical response of breast cancer patients to a neoadjuvant regimen that included a CSR-specific agent. Collectively, these results suggest therapeutic opportunities to target the CSR phenotype in a relevant cohort of cancer patients. Refer to individual Series. This SuperSeries is composed of the following subset Series: GSE24578: Basal gene expression of breast cancer cell lines GSE24716: Expression data from CD133+ and CD133- glioma cells
Project description:We assessed alternative splicing in breast cancer through global profiling of transcriptomes of basal and luminal subtype cell lines using Affymetrix Human Junction Array.
Project description:The ets transcription factor ELF5 specifies the differentiation of mammary progenitor cells to establish the milk-secreting lineage. ER- and poor prognosis basal breast cancers arise from this progenitor cell and these cancers express high levels of Elf5. Knockdown of ELF5 expression in basal breast cancer cell lines, or forced expression in luminal breast cancer cell lines, resulted in reduced cell proliferation. Transcript profiling and chromatin immunoprecipitation revealed that the transcriptional activity of ELF5 specified the gene expression patterns that distinguish basal from luminal breast cancer, including suppression of FOXA1, GATA3 and ER, key estrogen-action genes. Tamoxifen treatment of luminal MCF7 cells upregulated Elf5 expression and cells that acquired resistance to Tamoxifen became dependent on ELF5 for proliferation. ELF5 is a regulator of breast cancer cell proliferation, transcriptionally specifies the basal molecular subtype and is utilised by ER+ breast cancer cells to escape proliferative arrest caused by Tamoxifen. Elf5 was knocked down via siRNA in basal HCC1937 cell lines, in triplicate. Elf5 was induced in luminal T47D and MCF7 cell lines via a doxycycline inducible expression vector, in duplicate.
Project description:In order to identify new targets for basal-like breast cancers, we performed Methyl-Seq of 10 breast cancer cell lines. Basal-like cell lines (MDAMB231, MDAMB436, HCC1937, SUM149, SUM1315 and MCF10A) were compared to luminal cell lines (MCF7 and T47D). Moreover we could also study BRCA1 influence on methylome of basal-like breast cancer. 4 of our cell lines are indeed BRCA1 mutated (MDAMB436, HCC1937, SUM149 and SUM1315) and we also developed 2 cell lines that come from the BRCA1 mutated SUM1315 cell line stably transfected with empty LXSN plasmid (SUM1315-LXSN) or with a BRCA1 coding plasmid (SUM1315-BRCA1).
Project description:Given the very substantial heterogeneity of most human cancers, it is likely that most cancer therapeutics will be active in only a small fraction of any population of patients. As such, the development of new therapeutics, coupled with methods to match a therapy with the individual patient, will be critical to achieving significant gains in disease outcome. One such opportunity is the use of expression signatures to identify key oncogenic phenotypes that can serve not only as biomarkers but also as a means of identifying therapeutic compounds that might specifically target these phenotypes. Given the potential importance of targeting tumors exhibiting a stem-like phenotype, we have developed an expression signature that reflects common biological aspects of various stem-like characteristics. The Consensus Stemness Ranking (CSR) signature is upregulated in cancer stem cell enriched samples, at advanced tumor stages and is associated with poor prognosis in multiple cancer types. Using two independent computational approaches we utilized the CSR signature to identify clinically useful compounds that could target the CSR phenotype. In vitro assays confirmed selectivity of several predicted compounds including topoisomerase inhibitors and resveratrol towards breast cancer cell lines that exhibit a high-CSR phenotype. Importantly, the CSR signature could predict clinical response of breast cancer patients to a neoadjuvant regimen that included a CSR-specific agent. Collectively, these results suggest therapeutic opportunities to target the CSR phenotype in a relevant cohort of cancer patients. CD133+ and CD133- cells were separated from two glioma xenograft tumors. Both CD133+ and CD133- glioma cells were cultured in serum-free media for 48 hours in the presence of absence of laminin.
Project description:In order to identify new targets for basal-like breast cancers, we performed RNA-Seq of 10 breast cancer cell lines. Basal-like cell lines (MDAMB231, MDAMB436, HCC1937, SUM149, SUM1315 and MCF10A) were compared to luminal cell lines (MCF7 and T47D). Moreover we could also study BRCA1 influence on transcriptome of basal-like breast cancer. 4 of our cell lines are indeed BRCA1 mutated (MDAMB436, HCC1937, SUM149 and SUM1315) and we also developed 2 cell lines that come from the BRCA1 mutated SUM1315 cell line stably transfected with empty LXSN plasmid (SUM1315-LXSN) or with a BRCA1 coding plasmid (SUM1315-BRCA1).
Project description:During cancer progression, carcinoma cells encounter a variety of cytotoxic stresses such as hypoxia, nutrient deprivation, and low pH as a result of inadequate vascularization. To maintain survival and growth in the face of these physiologic stressors, a set of adaptive response pathways are induced. One adaptive pathway well studied in other contexts is the unfolded protein response (UPR), of which XBP1 is an important component. We used microarrays to detect transcriptome profile changes after XBP1 knockdown in breast cancer cell lines, and identify genes and pathways regulated by XBP1, which could help elucidate how XBP1 mediates the adaptive response of breast cancer to cytotoxic stresses. We extracted RNA and hybridized it to Affymetrix microarrays in two breast cancer cell lines (T47D and MDA-MB-231) under treated (hypoxia and glucose deprivation) or untreated conditions with XBP1 knockdown or not.
Project description:mRNA expression profile of cultured Breast Cancer cell line measured by Affymetrix microarrays Whole genome expression profile of 32 breast cancer cell lines were analyzed with 3 biological replicates.
Project description:Basal-like and luminal breast tumors have distinct clinical behavior and molecular profiles, yet the underlying mechanisms are poorly defined. To interrogate processes that determine these distinct phenotypes and their inheritance pattern, we generated somatic cell fusions and performed integrated genetic and epigenetic (DNA methylation and chromatin) profiling. We found that the basal-like trait is generally dominant and it is largely defined by epigenetic repression of luminal transcription factors. Definition of super-enhancers highlighted a core program common in luminal cells but high degree of heterogeneity in basal-like breast cancers that correlates with clinical outcome. We also found that protein extracts of basal-like cells is sufficient to induce luminal-to-basal phenotypic switch implying a trigger of basal-like autoregulatory circuits. We determined that KDM6A might be required for luminal-basal fusions, and identified EN1, TBX18, and TCF4 as candidate transcriptional regulators of luminal-to-basal switch. Our findings highlight the remarkable epigenetic plasticity of breast cancer cells. Bisulphite converted DNA from 20 breast cancer cell lines were hybridized to the Illumina Infinium HumanMethylation450 BeadChip.
Project description:We sought to build a catalog of epitopes presented by breast cancers using a renewable resource of well-characterized breast cancer cell lines. Starting from 70 breast cancer cell lines, we measured MHC class I abundance and used pre-existing RNAseq data to identify either HLA-A*02 or MHC class I-positive cell lines. For 20 of these cell lines, we used “reverse” immunogenetics, in which MHC class I-loaded peptides are recovered and their sequences are determined by mass spectrometry. We identified more than 2,700 unique MHC class I-bound peptides from a panel of basal, luminal, and claudin-low subtype of cell lines. HLA-A*02 binding prediction across all tested cell lines revealed a model which described the distribution of HLA-A*02-binding peptides and allowed us to identify those peptides most likely to be presented on HLA-A*02. Comparing the peptides that we identified to published literature found that more than 1500 peptides had been identified in previous studies and that 18 of these peptides have been shown to be immunogenic. Overall, this high throughput identification of MHC class I-loaded peptides is an effective strategy for systematic characterization of cancer epitopes and could be employed in a design of multipeptide-based anticancer vaccine.