Project description:Women with germline mtuation in BRCA1 have increased risk for developing hereditary breast cancer. The role of the epitheilum-assocaited niche during BRCA1-driven tumor intiation remains unclear. Here, we show that the pre-malignant stromal niche promotes epithelial prolifeation and BRCA1-driven cancer intiation in trans. Using single-cell RNA seq analysis of human pre-neoplastic BRCA1 and control breast tissue, we show that stromal cells provide numerous pro-proliferative paracrine signals inducing epithelial proliferation.
Project description:Brca1 mutation predisposes women to early onset of breast and ovarian cancers.Through its diverse functions in DNA damage repair, cell cycle control, transcription regulation, ubiquitination and so on, BRCA1 acts as a very significant tumor suppressor and genomic safeguard. Brca1 deficiency induces severe cellular stress, when occurring in the mammary glands, it impairs the regular developmental process and eventually causes tumorigenesis due to accumulation of genome instability and other mechanisms. The Brca1-defiencient mouse mammary tumor were characterized with great tumoral heterogeneity, which is in line with the human breast cancers carrying BRCA1 mutations. Here we studied the molecular complexicity of Brca1-deficient mouse mammary tumors vie Dropseq.
Project description:This SuperSeries is composed of the following subset Series: GSE32727: EMT inducers catalyze malignant transformation of mammary epithelial cells and drive tumorigenesis towards claudin-low tumors [human] GSE32904: EMT inducers catalyze malignant transformation of mammary epithelial cells and drive tumorigenesis towards claudin-low tumors [mouse] Refer to individual Series
Project description:Brca1 mutation predisposes women to early onset of breast and ovarian cancers.Through its diverse functions in DNA damage repair, cell cycle control, transcription regulation, ubiquitination and so on, BRCA1 acts as a very significant tumor suppressor and genomic safeguard. Brca1 deficiency induces severe cellular stress, when occurring in the mammary glands, it impairs the regular developmental process and eventually causes tumorigenesis due to accumulation of genome instability and other mechanisms. The Brca1-defiencient mouse mammary tumor were characterized with great tumoral heterogeneity, which is in line with the human breast cancers carrying BRCA1 mutations. Here we studied the molecular complexicity of Brca1-deficient mouse mammary tumors vie single cell RNA sequencing.
Project description:In breast cancer related to the BRCA1 mutation, luminal progenitor cells are believed to be the cells of origin, yet how these cells transform into invasive cancer cells remain poorly understood. Here, we combine single-cell epigenomic and transcriptomic data to reconstitute sequences of events in luminal cells that lead to tumorigenesis. Upon deletion of Trp53 and Brca1, we find that luminal progenitors display an extensive epigenomic disorder associated with a loss of cell identity. These cells then progress to tumor formation through a partial epithelial-to-mesenchymal transition, orchestrated by Snail and the timely activation of immunosuppressive and FGF signaling with their microenvironment. In human samples, pre-tumoral changes can be detected in early stage, basal-like tumors, which rarely recur, as well as in normal-like mammary glands of BRCA1 mutation carriers who have had cancer. Our study fills critical gaps in our understanding of BRCA1-driven tumorigenesis, opening perspectives for the early monitoring of individuals with high cancer risk.
Project description:In breast cancer related to the BRCA1 mutation, luminal progenitor cells are believed to be the cells of origin, yet how these cells transform into invasive cancer cells remain poorly understood. Here, we combine single-cell epigenomic and transcriptomic data to reconstitute sequences of events in luminal cells that lead to tumorigenesis. Upon deletion of Trp53 and Brca1, we find that luminal progenitors display an extensive epigenomic disorder associated with a loss of cell identity. These cells then progress to tumor formation through a partial epithelial-to-mesenchymal transition, orchestrated by Snail and the timely activation of immunosuppressive and FGF signaling with their microenvironment. In human samples, pre-tumoral changes can be detected in early stage, basal-like tumors, which rarely recur, as well as in normal-like mammary glands of BRCA1 mutation carriers who have had cancer. Our study fills critical gaps in our understanding of BRCA1-driven tumorigenesis, opening perspectives for the early monitoring of individuals with high cancer risk.
Project description:Most BRCA1-associated breast tumors are basal-like yet originate from luminal progenitor cells. BRCA1 is best known for its functions in DNA repair and resolution of DNA replication stress. However, it is unclear whether loss of these ubiquitously important functions of BRCA1 fully explains the cell lineage-specific increase in breast tumor development. Cell culture-based studies implicate BRCA1 in elimination of R-loops, DNA-RNA hybrid structures involved in transcriptional regulation and genetic instability. We found that BRCA1 mutation-associated R-loop accumulates preferentially in luminal epithelial cells of cancer-free human breast tissue, and at the 5' end of those genes that experience promoter-proximal RNA polymerase II (Pol II) pausing. Genetic ablation of mouse NELF-B/COBRA1, a Pol II-pausing factor and BRCA1-binding protein, in Brca1 knockout mouse mammary epithelium ameliorates R-loop accumulation and reduces mammary tumorigenesis. Our studies show that Pol II pausing is a previously unappreciated contributor to BRCA1-associated R-loop accumulation and breast cancer development.
Project description:In pancreatic cancer, select cells within a homogeneous epithelium drive tumorigenesis in response to an environmental trigger, suggesting key uncharacterized roles for epigenetics and cellular context. To investigate epigenetic plasticity in early tumorigenesis, we performed single-cell transcriptional and chromatin accessibility sequencing of Kras-mutant pancreatic cancer models, encompassing initiation to malignant stages and wild-type tissue. Our analysis identifies a few progenitor states that correspond to known cells-of-origin, exhibit the greatest measured epigenetic plasticity, and are primed for diverse neoplastic fates. Plasticity is strongly associated with accessibility near receptor and ligand loci. We delineated robust communication modules and a feedback loop between IL33-expressing epithelial and immune cells with broad tissue impacts, which we confirmed by genetic perturbation in mice. Our results promise to nominate early interception strategies for this lethal cancer.
Project description:In pancreatic cancer, select cells within a homogeneous epithelium drive tumorigenesis in response to an environmental trigger, suggesting key uncharacterized roles for epigenetics and cellular context. To investigate epigenetic plasticity in early tumorigenesis, we performed single-cell transcriptional and chromatin accessibility sequencing of Kras-mutant pancreatic cancer models, encompassing initiation to malignant stages and wild-type tissue. Our analysis identifies a few progenitor states that correspond to known cells-of-origin, exhibit the greatest measured epigenetic plasticity, and are primed for diverse neoplastic fates. Plasticity is strongly associated with accessibility near receptor and ligand loci. We delineated robust communication modules and a feedback loop between IL33-expressing epithelial and immune cells with broad tissue impacts, which we confirmed by genetic perturbation in mice. Our results promise to nominate early interception strategies for this lethal cancer.