Project description:The expression of the transcription factor SOX4 is increased in many human cancers, however, the pro-oncogenic capacity of SOX4 can vary greatly depending on the tumor-type. Both the contextual nature and the mechanisms underlying the pro-oncogenic SOX4 response remain unexplored. Here, we demonstrate that in mammary tumorigenesis, the SOX4 transcriptional network is dictated by the epigenome and is enriched for pro-angiogenic processes. We show that SOX4 directly regulates endothelin-1 (ET-1) expression and thereby promotes tumor-induced angiogenesis both in vitro and in vivo. Furthermore, in breast tumors, SOX4 expression correlates with blood vessel density and size, and predicts poor-prognosis in breast cancer patients. Our data provide novel mechanistic insights into context-dependent SOX4 target gene selection, and uncover a novel pro-oncogenic role by promoting tumor-induced angiogenesis. These findings establish a key role for SOX4 in promoting metastasis through exploiting diverse pro-tumorigenic pathways.
Project description:The transcription factor SOX4 is widely expressed during development and is essential to maintain progenitor pools in a variety of organs. In breast cancer SOX4 has been shown to be associated with poor survival and increased tumor size and metastasis formation. This has mostly been attributed to the ability of SOX4 to regulate Epithelial-to-Mesenchymal-Transition (EMT). However, SOX4 regulates target gene transcription in a plastic manner that is dependent on the cellular and epigenetic context. In this study we have investigated the loss of SOX4 in mammary tumor development utilizing organoids derived from a PyMT genetic mouse model. CRISPR-mediated loss of SOX4 led to a strong impairment in growth of primary mammary tumors and subsequent metastases through an EMT-independent mechanism. Instead, SOX4 is required for inhibiting differentiation by controlling genes that are highly activated in foetal mammary stem cells (fMaSC). These SOX4-dependent genes are associated with cell cycle progression, DNA biosynthesis, RNA processing and ribosome biogenesis suggesting that SOX4 controls active cycling of tumor cells. Analysis of genes co-expressed with SOX4 in the TCGA and METABRIC studies revealed that these cell cycle-related genes correlate with SOX4 expression in human tumors. Our study identifies a novel role for SOX4 in maintaining mammary tumors in an undifferentiated proliferative state.
Project description:Overexpression of SOX4 in various kinds of cancers specimen was associated with poor prognosis of patients; however, the role of SOX4 in angiogenesis or tumor microenvironment modulation remains unclear. Therefore the endogenous SOX4 was knockout and the differential gene expression between Hep3B and Hep3B SOX4-/- cells were examined via genechip. We found that the differentially expressed genes, EzH2, a SOX4-associated partner, and CXCL12, were repressed in Hep3B SOX4-/- cells compared with parental Hep3B; these results were further assessed via qRT-PCR in Hep3B SOX4-/- versus Hep3B cells.
Project description:We have investigated the proteome changes induced by SOX4 overexpression in HCT-116 cells using iTRAQ-based quantitative proteomics. Bioinformatics analysis revealed that HDAC1 could be one of the important regulators in cancer stem cells (CSCs) maintenance. We found that SOX4 transcriptionally regulates HDAC1 to support the stemness of cancer stem cells (CSCs). This work revealed a novel underlying mechanism, SOX4-HDAC1 axis, for stemness maintenance of human cancer.
Project description:The SOX4 gene belongs to a family of transcription factors and we previously unveiled SOX4 gene amplification and over-expression in a subset of lung cancers, indicating it may constitute a driver oncogene. Here, we searched for SOX4 transcriptional targets and investigate their involvement in lung development and carcinogenesis. We abrogated SOX4 expression in the NIH-H522 lung cancer cell line, carrying SOX4 amplification and over-expression, using an inducible short-hairpin system. Global analysis of gene expression identified about 90 genes down-regulated after SOX4 abrogation many of them related to neural development. We also demonstrated recruitment of SOX4 to many of these promoters, evidencing their nature as direct transcriptional targets of SOX4. Most of these transcripts were significantly increased in lung cancer cells with ectopic SOX4 over-expression and in lung tumors with high levels of SOX4. Conversely, many of them exhibited significant low expression levels in embryonic fibroblasts from Sox4-/- mice. We generated H522-derived cells that down-regulate SOX4 in an inducible manner. The H522 cells were transfected with a tetracycline (tet) repressor expression construct and a tet-repressor-controlled expression vector (tet-on) containing a shSOX4. An stable clone, H522Tr-shSOX4-1, which down-regulate SOX4 expression by 90%, 48 hours after adding doxycycline, was chosen for further analysis. To determine the gene expression profile characteristic of SOX4 depleted expression we compared the global gene expression of the parental H522 cells to the H522Tr-shSOX4-1 cells at 0, 24 and 96 hrs after inducing the shSOX4 with doxycycline using the Whole Human Genome Microarray from Agilent.
Project description:Dysregulation of PI3K/Akt signaling is a dominant feature in basal-like or triple-negative breast cancers (TNBC). However, the mechanisms regulating this pathway are largely unknown in this subset of aggressive tumors. Here we demonstrate that the transcription factor SOX4 is a key regulator of PI3K signaling in TNBC. Genomic and proteomic analyses coupled with mechanistic studies identified TGFBR2 as a direct transcriptional target of SOX4 and demonstrated that TGFBR2 is required to mediate SOX4-dependent PI3K signaling. We further report that SOX4 and the SWI/SNF ATPase SMARCA4, which are uniformly overexpressed in basal-like tumors, form a previously unreported complex that is required to maintain an open chromatin conformation at the TGFBR2 regulatory regions in order to mediate TGFBR2 expression and PI3K signaling. Collectively, our findings delineate the mechanism by which SOX4 and SMARCA4 cooperatively regulate PI3K/Akt signaling and suggest that this complex may play an essential role in TNBC genesis and/or progression. Kinase enrichment proteomic analysis was performed using HCC1143 breast cancer cells treated with a control siRNA pool or a pool targeting SOX4 in biological triplicate to evaluate the effects on the functional kinome.
Project description:The platelet-derived growth factor (PDGF) signaling system contributes to tumor angiogenesis and vascular remodeling. Here, we show PDGF-BB markedly induces erythropoietin (EPO) mRNA and protein expression by targeting the PDGFR-beta+ stromal and perivascular compartments. In mouse tumor models, PDGF-BB-induced EPO promotes tumor growth via two mechanisms: 1) paracrine stimulation of tumor angiogenesis by directly inducing endothelial cell proliferation, migration, sprouting and tube formation; and 2) endocrine stimulation of extramedullary hematopoiesis leading to increased oxygen perfusion and protection against tumor-associated anemia. Similarly, delivery of an adenovirus-PDGF-BB to tumor-free mice markedly increases EPO production and hematopoietic parameters. An EPO blockade specifically attenuates PDGF-BB-induced tumor growth, angiogenesis and hematopoiesis. At the molecular level, we show that the PDGF-BB-PDGFR-beta signaling system activates EPO promoter via in part transcriptional regulation of ATF3 by possible association with c-Jun and SP1. These findings uncover a novel mechanism of PDGF-BB-induced tumor growth, angiogenesis and hematopoiesis. Comparison of S17 stromal cells treated with PDGF-BB for 72h to control
Project description:The SOX4 gene belongs to a family of transcription factors and we previously unveiled SOX4 gene amplification and over-expression in a subset of lung cancers, indicating it may constitute a driver oncogene. Here, we searched for SOX4 transcriptional targets and investigate their involvement in lung development and carcinogenesis. We abrogated SOX4 expression in the NIH-H522 lung cancer cell line, carrying SOX4 amplification and over-expression, using an inducible short-hairpin system. Global analysis of gene expression identified about 90 genes down-regulated after SOX4 abrogation many of them related to neural development. We also demonstrated recruitment of SOX4 to many of these promoters, evidencing their nature as direct transcriptional targets of SOX4. Most of these transcripts were significantly increased in lung cancer cells with ectopic SOX4 over-expression and in lung tumors with high levels of SOX4. Conversely, many of them exhibited significant low expression levels in embryonic fibroblasts from Sox4-/- mice.
Project description:SOX4 is a critical developmental transcription factor in vertebrates and is required for precise differentiation and proliferation in multiple tissues. In addition, SOX4 is overexpressed in many human malignancies, but the precise role of SOX4 in cancer progression is not well understood. Here we have identified the direct transcriptional targets of SOX4 using a genome-wide localization ChIP-chip analysis. Keywords: ChIP-chip