Project description:TSV40ER and hTERT immortalized mammospheres undergo transformation in culture to generate breast cancer stem cells The stem cell hypothesis of cancer predicts that cancers arise from the transformation of normal stem/progenitor cells present within adult tissues. However, the molecular mechanisms that lead to the transformation of these cells remain largely unknown, mainly owing to the lack of suitable model systems. In this study, we have generated an immortalized breast epithelial cell line, NBLE, by over-expressing the SV40 Early Region and the catalytic domain of human telomerase into mammosphere-derived cells that are enriched in breast stem/progenitor cells. While primary mammospheres fail to grow beyond four passages in suspension culture, NBLE cells propagated continuously generating spheres at a high frequency of 35%. These cells also expressed stemness-related genes, and differentiated into both luminal and myoepithelial lineages. Interestingly, after around 135 population doublings in culture, the late passage cells exhibited a mesenchymal morphology and contained >90% of CD44+/CD24Low/- cells resembling breast cancer stem cells. When injected subcutaneously into nude mice, the late passage NBLEs formed invasive tumors closely resembling breast adenocarcinomas, the most common type of breast cancer. The transformed NBLE cells showed hyperactivation of Wnt, Hh and TGFbeta pathways, suggesting that the deregulation of these self-renewal pathways may have in part contributed to tumorigenesis. Gene expression analysis further revealed a high degree of similarity with breast cancer stem cells. Thus, our study provides a unique model system to study signaling pathways involved in self-renewal, differentiation, and transformation of breast stem/progenitor cells. Additionally, the NBLE cells can be utilized for screening drugs specifically targeting breast cancer stem cells. NBLE cells were generated by over-expressing SV40ER and hTERT into mammosphere-derived cells. These cells harnored CD44+/CD24- fraction that resembled breast cancer stem cells. To understand the unique gene expression of this fraction we performed microarray on CD44+/CD24- versus rest fractions from NBLE cells (Rep 1 and Rep 2). To see if this gene profile has any similarity with breast cancer stem cells, we performed CD44+/CD24- versus rest microarray on two primary breast tumors (CB272 and CB258-Rep1 andRep2).
Project description:Barrett’s esophagus confers significant risk of esophageal adenocarcinoma. We have established the cloning of patient-matched stem cells of Barrett’s, gastric, and esophageal epithelium. Transplantation of transformed Barrett’s stem cells yielded tumors with hallmarks of esophageal adenocarcinoma, whereas transformed esophageal stem cells produced squamous cell carcinomas. These findings define a stem cell target in a precancerous lesion for preemptive therapies.
Project description:In the present study we have isolated and characterized cancer stem cells and non-cancer stem cells (bulk tumor cells) from high grade human colorectal cancer cell line HCT116 and low grade human colorectal cancer cell line HT29. For this study, cancer stem cells and non-cancer stem cells (bulk tumor cells) were isolated from HCT116 and HT29 human colorectal cancer cell line. For isolating cancer stem cells by FACS, CD44 and CD166 tagged with V450 and PE respectively were used. CD44+CD166+ was the cancer stem cell population and CD44-CD166- was designated as the non-cancer stem cell (bulk tumor cells) population for this study. RNA was isolated from the isolated cell populations and microarray was done to study the whole genome transcriptomic changes.
Project description:Tobacco in its smoke and smokeless form are major risk factors for ESCC (esophageal squamous cell carcinoma). However, molecular alterations associated with smokeless tobacco exposure are poorly understood. In the Indian subcontinent, tobacco is predominantly consumed in chewing form. An understanding of molecular alterations associated with chewing tobacco exposure is vital for identifying molecular markers and potential targets. We developed an in-vitro cellular model by exposing non-transformed esophageal epithelial cells to chewing tobacco over eight month period. Chronic exposure to chewing tobacco led to increase in cell proliferation, invasive ability and anchorage independent growth indicating cell transformation. Molecular alterations associated with chewing tobacco exposure were characterized by carrying out exome sequencing and quantitative proteomic profiling of parental cells and chewing tobacco exposed cells. Quantitative proteomic analysis revealed that established cancer stem cell markers are elevated in tobacco treated cells. Decreased expression of enzymes associated with the glycolytic pathway and increased expression of a large number of mitochondrially localized proteins involved in the electron transport chain as well as enzymes of TCA cycle were also identified. Electron micrographs revealed increase in number and size of mitochondria. Based on these observations, we hypothesise that chronic treatment of esophageal epithelial cells with tobacco leads to a cancer stem cell-like phenotype. These cells also show characteristic OXPHOS phenotype which can be potentially targeted as a therapeutic strategy.
Project description:Barrett’s esophagus is a precancerous lesion that confers a significant risk of esophageal adenocarcinoma. Strategies for selective eradication of Barrett’s have been stymied by our inability to identify the Barrett’s stem cell. Here we employ novel technologies to clone patient-matched stem cells of Barrett’s, gastric, and esophageal epithelium. Genomic analyses of Barrett’s stem cells reveal a patient-specific mutational spectrum ranging from low somatic variation similar to patient-matched gastric epithelial stem cells to ones marked by extensive heterozygous alteration of genes implicated in tumor suppression, epithelial planarity, and epigenetic regulation. Transplantation of transformed Barrett’s stem cells yields tumors with hallmarks of esophageal adenocarcinoma, whereas transformed esophageal stem cells yield squamous cell carcinomas. Thus Barrett’s develops from cells distinct from local eponymous epithelia, emerges without obvious driver mutations, and likely progresses through and from the generation of dominant clones. These findings define a stem cell target for preemptive therapies of a precancerous lesion.
Project description:To delineate the role of hypoxia in esophageal epithelial biology, we carried out gene array experiments using a non-transformed immortalized diploid human esophageal cell line, EPC2-hTERT (Mol Cancer Res. 2003;1:729-38). Unlike cancer cell lines, EPC2-hTERT has no genetic alterations at early passages that may affect the cellular response to hypoxia.
Project description:Deregulation of Src kinases is associated with cancer. We previously showed that SrcDN conditional expression in MCF7 cells diminished tumorigenesis and causes tumor regression in mice. However, it remained unclear whether SrcDN affected breast cancer stem cell functionality or it reduced tumor mass. Here, we address this question by isolating an enriched population of BCSCs (ESA+-CD44+-CD24-) and the tumor-differentiated cells (ESA+-CD44+-CD24+) from MCF7-Tet-On-SrcDN. ESA+-CD44+-CD24- grew in suspension forming mammospheres, and producing tumors in nude mice, while ESA+-CD44+-CD24+ were poorly/non-tumorigenic. Doxycycline-induction of SrcDN inhibited BCSC tumorigenesis, selfrenewal, and stem-cell markers expression. SrcDN significantly inhibited SFE, and stem-cell markers expression in triple-negative breast cancer (TNBC) MDA-MB-231 and SUM159PT cells. Inducible depletion of c-Src caused similar effects in MDA-MB-231 cells. In MCF7-Tet-On-SrcDN derived mammospheres SrcDN-induction inhibited expression, and activity of hexokinase, pyruvate kinase and lactate dehydrogenase, resulting in diminished glucose consumption and lactate production, which restricted Warburg effect. Thus, c-Src functionality is important for breast cancer stem cell maintenance and renewal, tumorigenicity, and stem cell transcription factor expression, effects linked to glucose metabolism reduction.