Project description:The erythropoietin (EPO) hormone induces red blood cell production and its recombinant form is the most prescribed drug for the treatment of anemia, including that arising in cancer patients. Based on randomized trials showing that EPO administration to cancer patients result in a decreased survival, we investigated the impact of EPO modulation on tumorigenesis. Using genetically engineered mouse models of breast cancer we found that EPO promoted tumorigenesis by activating JAK/STAT signaling specifically in breast tumor initiating cells (TICs) and promoting their self-renewal. Moreover, we define an active role for endogenous EPO in breast cancer progression and breast TIC self-renewal and demonstrate a potential application of EPO pathway inhibition in breast cancer therapy. reference x sample
Project description:The erythropoietin (EPO) hormone induces red blood cell production and its recombinant form is the most prescribed drug for the treatment of anemia, including that arising in cancer patients. Based on randomized trials showing that EPO administration to cancer patients result in a decreased survival, we investigated the impact of EPO modulation on tumorigenesis. Using genetically engineered mouse models of breast cancer we found that EPO promoted tumorigenesis by activating JAK/STAT signaling specifically in breast tumor initiating cells (TICs) and promoting their self-renewal. Moreover, we define an active role for endogenous EPO in breast cancer progression and breast TIC self-renewal and demonstrate a potential application of EPO pathway inhibition in breast cancer therapy.
Project description:Using a syngeneic p53 null mouse mammary gland tumor model that closely mimics human breast cancer, we have identified by limiting dilution transplantation as well as in vitro mammosphere and clonogenic assays a Lin-CD29HighCD24High subpopulation of tumor-initiating cells. Differentially expressed genes in the Lin-CD29HighCD24High mouse mammary gland tumor-initiating cell population include those involved in DNA damage response and repair, as well as genes involved in epigenetic regulation previously shown to be critical for stem cell self-renewal. Keywords: tumor-initiating cells
Project description:The differentiation of stem-like cells of tumors may contribute to the cellular heterogeneity of breast cancers. We report the propagation of highly enriched mouse mammary cancer stem cells that retain the potential to differentiate both in vivo and in culture and their use to identify chemical compounds that influence both self-renewal and differentiation. We identify epithelial tumor initiating cells (ETIC) that expresses lineage markers of both basal and luminal mammary cell lineages and retains the potential to generate heterogeneous tumors similar to the tumor of origin from even single cells. ETIC can progress through a Rho associated coil-coil protein kinase 1 (ROCK1) dependent, epithelial to mesenchymal transition to generate a second cell type capable of initiating tumors of limited heterogeneity. The propagation of ETIC will increase the opportunities for identifying new therapeutic compounds that may inhibit or prevent progression of some types of breast cancer. These data compare the gene expression pattern of ETIC and MTIC. Total RNA obtained from ETIC and MTIC cells, allowing the comparison of gene expression patterns and the selection of potential targets.
Project description:Using established human CRC cell lines, we showed that progastrin expression were enriched under conditions that promote tumor-initiating cells (TIC) self-renewal.
Project description:Background. Pediatric high-grade gliomas (PHGG) are aggressive, undifferentiated CNS tumors with poor outcomes, for which no standard-of-care drug therapy currently exists. Through a knockdown screen for epigenetic regulators, we identified PRMT5 as essential for PHGG cell growth. We hypothesized that, similar to its effect in normal cells, PRMT5 promotes self-renewal of stem-like PHGG tumor initiating cells (TICs) essential for tumor growth. Methods. We conducted in vitro analyses, including limiting dilution studies of self-renewal, to determine the phenotypic effects of PRMT5 KD. We performed ChIP-Seq to identify PRMT5-mediated epigenetic changes and gene set enrichment analysis to identify pathways that PRMT5 regulates. Using an orthotopic xenograft model of PHGG, we tracked survival and histological characteristics resulting from PRMT5 KD or administration of a PRMT5 inhibitor ± radiation therapy (RT). Results. In vitro, PRMT5 KD slowed cell cycle progression, tumor growth and self-renewal. PRMT5 KD reduced H3K4me3 occupancy at genes associated with self-renewal, tumor formation and growth. In vivo, PRMT5 KD increased survival and reduced tumor aggressiveness; however, pharmacological inhibition of PRMT5 with or without RT did not improve survival. Conclusion. PRMT5 KD epigenetically reduced TIC self-renewal, leading to increased survival in preclinical models. Pharmacological inhibition of PRMT5 enzymatic activity may have failed in vivo due to insufficient reduction of PRMT5 activity by chemical inhibition, or this failure may suggest that non-enzymatic activities of PRMT5 are more relevant.
Project description:Background. Pediatric high-grade gliomas (PHGG) are aggressive, undifferentiated CNS tumors with poor outcomes, for which no standard-of-care drug therapy currently exists. Through a knockdown screen for epigenetic regulators, we identified PRMT5 as essential for PHGG cell growth. We hypothesized that, similar to its effect in normal cells, PRMT5 promotes self-renewal of stem-like PHGG tumor initiating cells (TICs) essential for tumor growth. Methods. We conducted in vitro analyses, including limiting dilution studies of self-renewal, to determine the phenotypic effects of PRMT5 KD. We performed ChIP-Seq to identify PRMT5-mediated epigenetic changes and gene set enrichment analysis to identify pathways that PRMT5 regulates. Using an orthotopic xenograft model of PHGG, we tracked survival and histological characteristics resulting from PRMT5 KD or administration of a PRMT5 inhibitor ± radiation therapy (RT). Results. In vitro, PRMT5 KD slowed cell cycle progression, tumor growth and self-renewal. PRMT5 KD reduced H3K4me3 occupancy at genes associated with self-renewal, tumor formation and growth. In vivo, PRMT5 KD increased survival and reduced tumor aggressiveness; however, pharmacological inhibition of PRMT5 with or without RT did not improve survival. Conclusion. PRMT5 KD epigenetically reduced TIC self-renewal, leading to increased survival in preclinical models. Pharmacological inhibition of PRMT5 enzymatic activity may have failed in vivo due to insufficient reduction of PRMT5 activity by chemical inhibition, or this failure may suggest that non-enzymatic activities of PRMT5 are more relevant.
Project description:Regulatory factors controlling stem cell identity and self-renewal are often active in aggressive cancers and are thought to promote their growth and progression. TCF3 (also known as TCF7L1) is a member of the TCF/LEF transcription factor family that is central in regulating epidermal and embryonic stem (ES) cell identity. We found that TCF3 is highly expressed in poorly differentiated human breast cancers, preferentially of the basal-like subtype. This suggested that TCF3 is involved in the regulation of breast cancer cell differentiation state and tumorigenicity. Silencing of TCF3 dramatically decreased the ability of breast cancer cells to initiate tumor formation, and led to decreased tumor growth rates. In culture, TCF3 promotes the sphere formation capacity of breast cancer cells and their self-renewal. We found that in contrast to ES cells, where it represses Wnt-pathway target genes, TCF3 promotes the expression of a subset of Wnt-responsive genes in breast cancer cells, while repressing another distinct target subset. In the normal mouse mammary gland Tcf3 is highly expressed in terminal end buds, structures that lead duct development. Primary mammary cells are dependent on Tcf3 for mammosphere formation, and its overexpression in the developing gland disrupts ductal growth. Our results identify TCF3 as a central regulator of tumor growth and initiation, and a novel link between stem cells and cancer. Cells infected with different shRNA vectors were either untreated, treated with control or Wnt3A condition medium. Condition medium treatments were done in biological repeats.
Project description:Glioblastoma (GBM), classified as a grade 4 glioma, is the most prevalent intrinsic malignancy of the central nervous system. Glioblastoma stem cells (GSCs) are small populations of GBM cells with self-renewal and multilineage differentiation capabilities and are considered responsible for the tumorigenesis and development of GBM. POSTN secreted from glioblastoma stem cells can recruit microglia and upregulate CD70 expression in microglia through the αVβ3/PI3K/AKT/NFκB pathway, which in turn promotes Treg development and functionality and supports the formation of an immunosuppressive tumor microenvironment.
Project description:In many mouse models of skin cancer, only a few tumors typically form although many cells competent for tumorigenesis receive the same oncogenic mutations. These observations suggest a selection process for defining tumor initiating cells. Here we use quantitative mRNA- and miR-Seq to determine the impact of HRasG12V on the transcriptome of keratinocytes. We discover that microRNA-203 is downregulated by HRasG12V. Using a knockout mouse model, we demonstrate that loss of microRNA-203 promotes selection and expansion of tumor-initiating cells. Conversely, restoration of microRNA-203 with an inducible model potently inhibits proliferation of these cells. We comprehensively identify microRNA-203 targets required for HRas-initiated tumorigenesis. These targets include important effectors of the Ras pathway and essential genes required for cell division. Together, this study establishes a role for the loss of microRNA-203 in promoting selection and expansion of HRas mutated cells and identifies a mechanism through which microRNA-203 antagonizes HRas-mediated tumorigenesis. Identifying mRNA and microRNA networks regulated by oncogenic HRasG12V in primary keratinocytes through the use of 3Seq and small-RNA-Sequencing. Additionally we utilize ribosome-profiling, 3Seq, Microarray and Ago2-HITS-CLIP approaches to identify novel miR-203 target genes.