Project description:Transforming growth factor-β (TGF-β) comprises a key component in the tumor microenvironment. It is reported that TGF-β can be pro-tumorigenic or anti-tumorigenic depending on various contexts. Some of the triple negative breast cancers highly express TGF-β, but pro-tumorigenic function of TGF-β in triple negative breast cancer cells is not fully known. Therefore, we analyzed genome-wide gene expression changes after stimulation with TGF-β in a triple negative breast cancer cell line, Hs578T cells.
Project description:Transforming growth factor (TGF)-β signaling enhances cancer cell plasticity by inducing epithelial-to-mesenchymal transition (EMT). Here, we identified a TGF-β-induced long non-coding RNA (lncRNA) LIMD1 Antisense RNA 1 (LIMD1-AS1) that strengthens the SMAD-mediated transcriptional response to TGF-β. The expression of LIMD1-AS1 is upregulated in breast cancer tissues compared to that of normal breast tissues, and high LIMD1-AS1 expression is associated with poor prognosis in breast cancer patients. Depletion of LIMD1-AS1 hinders TGF-β-induced EMT, migration, and extravasation of breast cancer cells. Mechanistically, LIMD1-AS1 promotes the interaction between SMAD3 and its transcriptional coactivator p300, and thereby enhances SMAD3 transcriptional activity and TGF-β/SMAD signaling. We showed that LIMD1-AS1 binds to the MAD homology 2 (MH2) domain of SMAD3 and the interferon-binding domain (IBiD) of p300. Displacing the binding of LIMD1-AS1 to p300 with its competitor interferon regulatory factor 3 (IRF3) suppressed the effects of LIMD1-AS1 on potentiating TGF-β/SMAD signaling. Moreover, blockage of p300 acetyltransferase activity with a pharmacological inhibitor, A-485, reduces the ability of LIMD1-AS1 to enhance SMAD3 transcriptional activity, TGF-β-induced EMT, and migration. This study reveals LIMD1-AS1 as a novel stimulator of TGF-β signaling by establishing a positive feedback loop and highlights its potential as a therapeutic target for breast cancer.
Project description:Epithelial-to-mesenchymal transition (EMT) plays a crucial role in metastasis, which is the leading cause of death in breast cancer patients. We show that Cdc42 GTPase-activating protein (CdGAP) promotes tumor formation and metastasis to lungs in the HER2-positive (HER2+) murine breast cancer model. CdGAP facilitates intravasation, extravasation, and growth at metastatic sites. CdGAP depletion in HER2+ murine primary tumors mediates crosstalk with a Dlc1-RhoA pathway and is associated with a transforming growth factor-β (TGF-β)-induced EMT transcriptional signature. To further delineate the molecular mechanisms underlying the pro-migratory role of CdGAP in breast cancer cells, we searched for CdGAP interactors by performing a proteomic analysis using HEK293 cells overexpressing GFP-CdGAP. We found that CdGAP interacts with the adaptor Talin to modulate focal adhesion dynamics and integrin activation. Moreover, HER2+ breast cancer patients with high CdGAP mRNA expression combined with a high TGF-β-EMT signature are more likely to present lymph node invasion. Our results suggest CdGAP as a candidate therapeutic target for HER2+ metastatic breast cancer by inhibiting TGF-β and Integrin/Talin signaling pathways.
Project description:Cancer Associated Fibroblasts (CAF) are a dominant and critical cell type of the tumour microenvironment and can lead to breast cancer progression. TGF-β has been reported to influence fibroblast to myofibroblast activation, which is similar to cancer associated fibroblast phenotype. To understand the mechanism of TGF-β mediated CAF phenotype, we have performed a comparative proteomic analysis of conditioned media from CAF (isolated from breast cancer biopsy tissues) and normal mammary fibroblasts engineered to over-express TGF-β1. Liquid chromatography/ tandem mass spectrometry (LC ESI Q-TOF-MS/MS) assay of conditioned media and Venn analysis of the acquired data, revealed approximately 185 common proteins secreted by the three fibroblast types (CAF, normal mammary fibroblasts and TGF-β over expressing mammary fibroblasts). Among these, 12 proteins exclusively overlap between normal fibroblasts and CAF and 20 proteins exclusively overlap between CAF and TGF-β1 over-expressing fibroblasts. This analysis reveals interesting targets which may be important in activation phenotype of CAF and breast cancer progression.
Project description:Analyze TGF-beta pathway transcriptional regulation in breast cancer stem cells with different responses upon TGF-beta pathway activation. Total RNA from four breast cell lines grown as mammospheres treated with recombinant TGF-beta or a TGF-beta receptor I inhibitor was used in the analysis.
Project description:Transforming growth factor-β (TGF-β) is a key factor for the development of prostate cancer metastases in bone. In breast cancer and melanoma, studies have shown how TGF-β regulates gene expression to allow cancer cells to adapt to the bone microenvironment. We used microarray analyses to characterize the effect of TGF-β on gene expression in prostate cancer cells in vitro.
Project description:Introgressed variants from other species can be an important source of genetic variation because they may arise rapidly, can include multiple mutations on a single haplotype, and have often been pretested by selection in the species of origin. Although introgressed alleles are generally deleterious, several studies have reported introgression as the source of adaptive alleles-including the rodenticide-resistant variant of Vkorc1 that introgressed from Mus spretus into European populations of Mus musculus domesticus. Here, we conducted bidirectional genome scans to characterize introgressed regions into one wild population of M. spretus from Spain and three wild populations of M. m. domesticus from France, Germany, and Iran. Despite the fact that these species show considerable intrinsic postzygotic reproductive isolation, introgression was observed in all individuals, including in the M. musculus reference genome (GRCm38). Mus spretus individuals had a greater proportion of introgression compared with M. m. domesticus, and within M. m. domesticus, the proportion of introgression decreased with geographic distance from the area of sympatry. Introgression was observed on all autosomes for both species, but not on the X-chromosome in M. m. domesticus, consistent with known X-linked hybrid sterility and inviability genes that have been mapped to the M. spretus X-chromosome. Tract lengths were generally short with a few outliers of up to 2.7 Mb. Interestingly, the longest introgressed tracts were in olfactory receptor regions, and introgressed tracts were significantly enriched for olfactory receptor genes in both species, suggesting that introgression may be a source of functional novelty even between species with high barriers to gene flow.
Project description:Grainyhead genes are involved in wound healing and developmental neural tube closure. In light of the high degree of similarity between the epithelial-mesenchymal transitions (EMTs) occurring in wound healing processes and the cancer stem cell-like compartment of tumors, including TGF-β-dependence, we investigated the role of a Grainyhead gene (GRHL2) in oncogenic EMT. Grainyhead was specifically down-regulated in the claudin-low subclass of mammary tumors and in the basal-B subclass of breast cancer cell lines. Functionally, GRHL2 suppressed TGF-β-induced, Twist-induced or spontaneous EMT, enhanced anoikis-sensitivity, and suppressed mammosphere generation in mammary epithelial cells. These effects were mediated, in part, by its suppression of ZEB1 expression, through direct repression of the ZEB1 promoter. GRHL2 also inhibited Smad-mediated transcription, and up-regulated mir200b/c as well as the TGF-β receptor antagonist, BMP2. The expression of GRHL2 in the breast cancer cell line MDA-MB-231 triggered a mesenchymal-to-epithelial transition and sensitized the cells to anoikis. These results indicate that GRHL2 is a suppressor of the oncogenic EMT. 3 biologic replicates for each cell line. Comparison of HMLE+Twist-ER cells expressing GRHL2/pMIG vs. HMLE+Twist-ER cells expressing empty pMIG.
Project description:The activation of RIG-I-like receptor (RLR) signaling in cancer cells is widely recognized as a critical cancer therapy method. The expected mechanism of RLR ligand-mediated cancer therapy involves the promotion of cancer cell death and strong induction of interferon (IFN)-β that affects the tumor microenvironment. We have recently shown that activation of RLR signaling in triple-negative breast cancer cells (TNBC) attenuates TGF-β signaling, which partly contributes to the promotion of cancer cell pyroptosis. However, the consequences of suppression of TGF-β signaling by RLR ligands with respect to IFN-β-mediated tumor suppression are not well characterized. This study showed that cytosolic induction of a typical RLR ligand polyI:C in cancer cells produces significant levels of IFN-β, which inhibits the growth of the surrounding cancer cells. In addition, IFN-β-induced cell cycle arrest in surrounding cancer cells was inhibited by the expression of constitutively active Smad3 (caSmad3). caSmad3 suppresses IFN-β expression through the alleviation of IRF3 binding to the canonical target genes, as suggested by ChIP-seq analysis. Based on these findings, a new facet of the pro-tumorigenic function of TGF-β that suppresses IFN-β expression is suggested when exploiting RLR-mediated cancer treatment in TNBC.