Project description:<p>In this study we used next generation deep sequencing technologies to analyze the genomes of Harvard University Stem Cell lines 63 and 64. We performed 101-bp paired-end whole genome sequencing of the two cell lines using Illumina HiSeq platforms. The sequence reads obtained were analyzed for copy number and used for replication timing analysis. Our data suggests that read depth profiles can be used to map replication timing in Embryonic Stem Cells (ESCs). Further we observe that replication profiles are highly correlated across ESCs but distinct from those of other cell types such as Lymphoblastoid Cell Lines (LCLs). These results demonstrated that read depth data from whole genome sequencing can be used to study variation in replication timing within the human population and across different cell types. Whole genome sequences from HUES63 and HUES64 used for this study are being submitted.</p>
Project description:Five molecular subtypes (Luminal A/B, HER2-enriched, Basal-like, and Claudin-low) with clinical implications have been identified. In this report, we evaluated molecular and phenotypic relationships of a large in vitro panel of human breast cancer cell lines (BCCLs), human mammary fibroblasts (HMFs) and human mammary epithelial cells (HMECs) with (1) breast tumors, (2) normal breast cell-enriched subpopulations and (3) human embryonic stem cells (hESCs) and bone marrow-derived mesenchymal stem cells (hMSC). First, by integrating genomic data of 337 breast samples with 93 cell lines we were able to identify all the intrinsic tumor subtypes in vitro, except for the Luminal A. Secondly, we observed that cell lines recapitulate the differentiation hierarchy observed in the mammary gland, with Claudin-low BCCLs and HMFs cells showing a stromal phenotype, HMECs showing a mammary stem cell/bipotent progenitor phenotype, Basal-like cells showing a luminal progenitor phenotype, and Luminal B cells showing a luminal phenotype. Thirdly, we identified Basal-like and highly migratory Claudin-low subpopulations of cells within a subset of triple-negative BCCLs (SUM149PT, HCC1143 and HCC38). Interestingly, both subpopulations within SUM149PT where found to have Tumor Initiating Cell (TIC) features, but the Basal-like subpopulation grew faster than the Claudin-low subpopulation. Finally, Claudin-low BCCLs were found to resemble the phenotype of hMSCs, whereas hESCs cells were found to have an epithelial phenotype without basal and luminal differentiation. The results presented here should help improve our understanding of the cell line model system through the appropriate pairing of cell lines with relevant in vivo tumor and normal cell counterparts. reference x sample