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: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.
Project description:The mechanisms that allow breast cancer cells to metabolically sustain growth are poorly understood. In breast cancer, FoxA1 transcription factor, along with estrogen receptor, regulates luminal cell specification and proliferation. Here we report that FoxA transcription factor family members FoxA1 and FoxA2 fuel cellular growth in breast cancer through the expression of a common target gene, namely the endothelial lipase (LIPG) We used microarrays to detail the genes that are under de control of FoxA transcription factors in MDA231 and MCF7 breast cancer cells
Project description:Breast cancer is the most common cancer in women worldwide and metastatic dissemination is the principal factor related to death by this disease. Breast cancer stem cells, are thought to be responsible for metastasis and chemoresistance.. In this study, based on whole transcriptome analysis from putative breast CSCs and reverse-engineering of transcription control networks, we were able to identify two networks associated to this phenotype.
Project description:The eukaryotic elongation factor-2 kinase, eEF2K, restricts protein translation elongation, and was identified as a potential therapeutic target for diverse types of cancers including triple negative breast cancer (TNBC; PMID: 25330770). We have recently found that inhibition of eEF2K synergizes with depletion of eukaryotic translation initiation factor 4E-binding protein 1 (eIF4EBP1; 4E-BP1), a suppressor of eukaryotic protein translation initiation factor 4E (eIF4E), leading to effective growth suppression of TNBC cells in culture. We performed LC-MS/MS analysis following depletion of eEF2K and/or 4EBP in a TNBC cell line, Hs578t (YoungJun Ju & Eldad Zacksenhaus, manuscript in revisions). Depletion of these factors had overlapping effects on the proteome with the highest impact on Collagen containing extracellular matrix (e.g. COL1A1). The complete LC-MS/MS data sets (control vehicle; eEF2K-depletion, 4EBP1-depletion; combined eEF2k plus 4EBP1-depletion) are provided herein.
Project description:Dysregulation of pathways due to mutations on oncogenes or tumor suppressors that leads to aberrant expression or activity of proteins is the most well understood mechanism that drives cancer initiation and progression. TRIB3, a member of the Tribbles family of pseudokinases, is often found dysregulated in cancer and has been associated with breast cancer initiation and metastasis formation. However, the underlying mechanisms by which TRIB3 contributes to these events are far from being understood. In contrast PPAR, a well-known transcription factor that belongs to the superfamily of nuclear receptors, has gained attention in recent years as drug target in breast cancer. PPAR possess anti-proliferative abilities and inducing its expression has been shown beneficial in different cancer models. In this study, we demonstrated that TRIB3 regulates PPAR expression in breast cancer cells and that TRIB3 interacts with the WRAD complex in these cells. We showed that TRIB3 expression influence H3K4me3 levels genome wide and specifically at the PPARG locus. All in all, our study situates TRIB3 as a new epigenetic regulator and represents a new line of research for the Tribbles scientific community, opening the door for future targeted therapeutic interventions for breast cancer patients
Project description:Cancer cells undergo transcriptional reprogramming to drive tumor progression and metastasis. Here, we identified the transcriptional complex, NELF (Negative elongation factor), as an important regulator of this process. Using cancer cell lines and patient-derived tumor organoids, we demonstrated that loss of NELF inhibits breast cancer tumorigenesis and metastasis. Specifically, we found that epithelial-mesenchymal transition (EMT) and stemness-associated genes are downregulated in NELF-depleted breast cancer cells. Quantitative Multiplexed Rapid Immunoprecipitation Mass spectrometry of Endogenous proteins (qPLEX-RIME) of NELF-E, a key subunit of NELF, reveals significant rewiring of NELF-E-associated chromatin partners as a function of EMT, and further illuminates a co-option of NELF-E with the key EMT transcription factor SLUG. Accordingly, loss of NELF-E led to impaired SLUG binding on chromatin. Through integrative transcriptomic and genomic analyses, we identified the histone acetyltransferase, KAT2B, as a key functional target of NELF-E-SLUG. Genetic and pharmacological inactivation of KAT2B ameliorate expression of critical EMT marker genes, phenocopying NELF ablation. Elevated NELF-E and KAT2B expressions are associated with poorer prognosis in breast cancer patients, highlighting the clinical relevance of our findings. Importantly, KAT2B knockout mice are viable, raising the exciting prospect of targeting this dependency therapeutically. Taken together, we uncovered a crucial role of the NELF-E-KAT2B epigenetic axis in breast cancer carcinogenesis.
Project description:Maintenance and propagation of breast cancer stem cells (BCSCs) is mediated via cytokine and growth factor networks. Direct in vivo linkage between dietary regulation of mammary stem (MaSC)/progenitor cell numbers and protection from breast cancer has not been reported. Here, we investigated the effect of post-weaning intake of soy protein isolate (SPI) relative to the control casein (CAS) diet on the stem/progenitor population and tumor formation in MMTV-Wnt1-Transgenic (Wnt1-Tg) female mice. Gene expression profile of the basal (MaSC-enriched) sub-population in preneoplastic Wnt1-Tg mice demonstrated a stem cell-like expression pattern and markedly suppressed expression of inflammatory cytokines, C-X-C family chemokines, and metastasis-associated genes with dietary SPI exposure. four Samples: two CAS diet, two SPI diet