Sox9 controls self-renewal of oncogene targeted cells and links tumor initiation and invasion [ChIP-Seq]
ABSTRACT: Sox9 is a transcription factor expressed in most solid tumors. However, the molecular mechanisms underlying Sox9 function during tumorigenesis remain unclear. Here, using a genetic mouse model of basal cell carcinoma (BCC), the most frequent cancer in human, we show that Sox9 is expressed from the earliest step of tumor formation in a Wnt/β-catenin dependent manner. Deletion of Sox9 together with the constitutive activation of Hedgehog (HH) signaling completely prevents BCC formation and leads to a progressive loss of oncogene expressing cells. Transcriptional profiling of oncogene expressing cells with Sox9 deletion, combined with in vivo ChIP-sequencing uncovers a cancer-specific gene network regulated by Sox9 that promotes stemness, extracellular matrix (ECM) deposition and cytoskeleton remodeling while repressing epidermal differentiation. Our study identifies the molecular mechanisms regulated by Sox9 that links tumor initiation and invasion. Sox9 ChIP-seq analysis in K14CreER SmoM2 cells.
Project description:Sox9 is a transcription factor expressed in most solid tumors. However, the molecular mechanisms underlying Sox9 function during tumorigenesis remain unclear. Here, using a genetic mouse model of basal cell carcinoma (BCC), the most frequent cancer in human, we show that Sox9 is expressed from the earliest step of tumor formation in a Wnt/β-catenin dependent manner. Deletion of Sox9 together with the constitutive activation of Hedgehog (HH) signaling completely prevents BCC formation and leads to a progressive loss of oncogene expressing cells. Transcriptional profiling of oncogene expressing cells with Sox9 deletion, combined with in vivo ChIP-sequencing uncovers a cancer-specific gene network regulated by Sox9 that promotes stemness, extracellular matrix (ECM) deposition and cytoskeleton remodeling while repressing epidermal differentiation. Our study identifies the molecular mechanisms regulated by Sox9 that links tumor initiation and invasion. Overall design: Basal interfolicular cells expressing SmoM2 in presence or absence of Sox9 were FACS isolated and RNA was extracted before being hybridized Affymetrix microarrays. We then obtained a genes of list deregulated in absence of Sox9 by comparing Sox9 wild type and conditional knock-out SmoM2 expressing cells.
Project description:Basal cell carcinoma initiating cells undergo profound and rapid reprogramming into embryonic hair follicle progenitor like fate upon SmoM2 expression. Activation of Wnt/β-catenin signaling pathways is required in a cell autonomous manner for the reprogramming of adult IFE progenitors into EHFP-like fate as well as for tumor initiation. We used MA to define the molecular changes that occur in basal cell carcinoma initiating cells form the first oncogenic hit to the development of invasive tumor and further on to investigate the role of Wnt/β-catenin signaling activation in molecular changes occurring early during BCC development. Basal interfollicular cells expressing SmoM2 were FACS isolated at different stages of tumor development and in β-catenin LOF condition for RNA extraction and hybridization on Affymetrix microarrays. By comparing the transcriptional profile of SmoM2 expressing cells with FACS-isolated cells from littermate control mice, we determined a list of genes differentially regulated by SmoM2 expression as specific SmoM2 signature.
Project description:Heart valve formation initiates when endothelial cells of the heart transform into mesenchyme and populate the cardiac cushions. The transcription factor, SOX9, is highly expressed in the cardiac cushion mesenchyme, and is essential for heart valve development. Loss of Sox9 in mouse cardiac cushion mesenchyme alters cell proliferation, embryonic survival, and disrupts valve formation. Despite this important role, little is known regarding how SOX9 regulates heart valve formation or its transcriptional targets. Therefore, we mapped putative SOX9 binding sites by ChIP-Seq in embryonic day (E) 12.5 heart valves, a stage at which the valve mesenchyme is actively proliferating and initiating differentiation. Embryonic heart valves have been shown to express a high number of genes that are associated with chondrogenesis, including several extracellular matrix proteins and transcription factors that regulate chondrogenesis. Consequently, we compared regions of putative SOX9 DNA-binding between E12.5 heart valves and E12.5 limb buds. We identified context-dependent and context–independent SOX9 interacting regions throughout the genome. Analysis of context-independent SOX9 binding suggests an extensive role for SOX9 across tissues in regulating proliferation-associated genes including key components of the AP-1 complex. Integrative analysis of tissue-specific SOX9 interacting regions and gene expression profiles on Sox9-deficient heart valves demonstrated that SOX9 controls the expression of several transcription factors with previously identified roles in heart valve development, including Twist1, Sox4, Mecom/Evi1 and Pitx2. Together, our data identifies SOX9 coordinated transcriptional hierarchies that control cell proliferation and differentiation during valve formation. Examination of SOX9 binding sites in E12.5 atrioventricular canal (AVC) and E12.5 embryonic limb and mRNA expression profiling in E12.5 WT and Sox9 mutant AVCs, in duplicate.
Project description:Sox9 is an SRY-related transcription factor required for expression of cartilaginous matrix genes in the developing skeletal system and heart valve structures. In contrast to positively regulating formation of cartilaginous matrix, Sox9 has also been shown to negatively regulate matrix mineralization associated with bone formation. While the transcriptional activation of Sox9 target genes during chondrogenesis has been well studied, the mechanisms by which Sox9 represses osteogenic processs are not so clear. To address this, we performed a genome-wide Sox9 ChIP-on-chip approach using neonatal mouse lim tissue. Chromatin immunoprecipitation was performed with pooled Sox9 antibodies and normal rabbit IgG as control using neonatal mouse limb tissue. Samples include Sox9 IP and IgG IP.
Project description:Mouse hair follicles undergo synchronized cycles. Cyclical regeneration and hair growth is fueled by hair follicle stem cells (HFSCs). We used RNA-seq to identify SOX9-dependent transcriptional changes and ChIP-seq to identify SOX9-bound genes in HF-SCs. Telogen quiescent hair follicle stem cells (HFSCs) and intefollicular epidermal cells (IFE) were FACS-purified for ChIP-sequcencing and HFSCs for RNA-Sequencing
Project description:Dysregulatio of Hh signaling has been shown to be involved in the formation of human medulloblastoma. We generated a mouse model (CAGGS-CreER;R26-SmoM2) of Hh related tumors. We used microarray to profile gene expression in Hh induced mouse medulloblastoma and identified distinct classes of up-regulated or down-regulated genes during Hh dependent tumorigenesis . Experiment Overall Design: Medulloblastoma samples and adjacent wild type cerebellar tissue from CAGGS-CreER;R26-SmoM2 mice were isolated for RNA extraction and hybridization on Affymetrix microarrays.
Project description:Background; Basal cell carcinoma (BCC) is the most common cancer in humans. The pathogenesis of BCC is associated with the sonic hedgehog (SHH) signaling pathway. Vismodegib, a smoothened inhibitor, that targets this pathway is now in clinical use for advanced BCC patients, but its efficacy is limited. Therefore, new therapeutic options for this cancer are required. Methods; We studied gene expression profiling of BCC tumour tissue coupled with laser capture microdissection to identify tumor specific receptor tyrosine kinase expression that can be targeted by small molecule inhibitors. The expression of selected molecules was confirmed by quantitative RT-PCR (qRT-PCR) and by immunohistochemistry. The action of kinase inhibitors was examined on primary normal human epidermal keratinocytes. Results; We found a >250 fold change increase (false discovery rate <10-4) of the oncogene, anaplastic lymphoma kinase (ALK) as well as its ligands, pleiotrophin and midkine in BCC compared to microdissected normal epidermis. qRT-PCR confirmed increased expression of ALK (p<0.05). Stronger staining of phosphorylated ALK in BCC tumour nests than normal skin was observed by immunohistochemistry. Additionally, Crizotinib, an FDA-approved ALK inhibitor, reduced keratinocyte proliferation in culture, whereas a c-Met, another receptor tyrosine kinase, inhibitor did not. Crizotinib significantly reduced the expression of GLI1 and CCND2 mRNA by approximately 60% and 20%, respectively (p<0.05). Conclusions; Our data suggest that ALK may increase GLI1 expression in parallel with the conventional SHH-pathway and promotes keratinocyte proliferation. Furthermore, an ALK inhibitor alone or in combination with targeting SHH-pathway molecules may be a potential treatment for BCC patients. Laser capture microdissection was performed on 5 cases of nodular/superficial BCC, 5 cases of infiltrative BCC.
Project description:Brahma related gene 1 (BRG1), a catalytic ATPase subunit of SWI/SNF chromatin remodeling complexes, is silenced in approximately 10% of human pancreatic ductal adenocarcinomas (PDA). We previously showed that BRG1 inhibits the formation of intraductal pancreatic mucinous neoplasm (IPMN) and IPMN-derived PDA from ductal cells. However, the role of BRG1 in pancreatic intraepithelial neoplasia (PanIN) from acinar cells remains elusive. Here, we investigated the role of BRG1 in PanIN initiation and maintenance and its underlying mechanisms. Exclusive elimination of Brg1 in acinar cells of Ptf1a-CreER; KrasG12D; Brg1f/f (KBC) mice impaired the formation of acinar-to-ductal metaplasia (ADM) and PanIN independent of the presence of p53 mutation. We found that Sox9 expression was down-regulated in both Brg1-depleted acinar cell explants and BRG1-depleted ADMs/PanINs. Sox9 overexpression rescued this PanIN-attenuated phenotype in KBC mice. Furthermore, Brg1-deletion in established PanIN by using an inducible dual recombinase system resulted in regression of the lesions in mice. Finally, expression of BRG1 and SOX9 was also positively correlated in human PanIN-derived PDAs. In summary, BRG1 is critical for both initiation and maintenance of PanIN. Mechanistically, this is mediated through positive regulation of SOX9 expression. Thus, the BRG1/SOX9 axis is a potential target for the prevention of PanIN-derived PDA. Overall design: Total pooled RNA from three individual acinar cell explants 24 h after Cre-expressing adenovirus infection were used. Mouse genotypes used for analysis were KrasG12D and KrasG12D; Brg1f/f.
Project description:The tongue is a muscular organ in the vertebrate oral cavity that performs complex functions in daily life, including feeding and phonetic articulation. The tongue consists of mesenchyme cells of two distinct origins: the muscle cells are derived from occipital somites whereas the tendons and other connective tissues derived from the cranial neural crest. Cranial neural crest cells are important for the initiation of tongue swelling and proper patterning of intrinsic and extrinsic tongue muscle groups. However, little is known regarding the molecular and cellular mechanisms of tongue morphogenesis. We show that the odd-skipped related 1 (Osr1) transcription factor exhibits dynamic expression in the tongue mesenchyme during early tongue development. Tissue-specific inactivation of Osr1 in the early neural crest cells resulted in ectopic cartilage formation in the mouse tongue. We show that Sox9, the master regulator of chondrocyte differentiation, is initially widely expressed in the neural crest derived mesenchyme in the tongue and subsequently down-regulated concomitant by up-regulation of Osr1 expression. Osr1 mutant embryos exhibit persistent expression of Sox9 and chondrocyte differentiation from the neural crest derived tongue mesenchyme. Further biochemical analyses indicate that Osr1 may directly suppresses Sox9 gene expression in the tongue mesenchyme. These data reveal a novel mechanism in suppression of chondrogenic fate during tongue development. Remarkably, the ectopic cartilage in the Osr1 mutant mice resembles the entoglossal cartilage naturally develops in the avian tongue. These results suggest that modulation of expression of Osr1 may underline the evolutionary divergence in tongue cartilage formation. RNAs were isolated from microdissected E12 embryonic mouse tongue of Osr1f/-;Wnt1cre and control littermates and characterized by RNAseq E12 mouse embryonic tongues were micro-dissceted, 3 pairs of control and mutant samples were pooled for the RNA extraction
Project description:A comprehensive analysis of Sox9 binding profiles in developing chondrocytes identified marked enrichment of an AP-1-like motif (Ohba et al. 2015). Here, we have explored the functional interplay between Sox9 and AP-1 in mammalian chondrocyte development. Among AP-1 family members, Jun and Fosl2 were highly expressed within prehypertrophic and early hypertrophic chondrocytes. Chromatin immunoprecipitation followed by DNA sequencing (ChIP-seq) showed a striking overlap in Jun- and Sox9-bound regions throughout the chondrocyte genome, a reflection of direct binding of each factor to target motifs in shared enhancers, and physical interactions of AP-1 with Sox9. In vitro expression analysis indicates that direct co-binding of Sox9 and AP-1 at target motifs enhanced target gene expression, while protein-protein interactions suppressed AP-1- and Sox9-driven transcription. Analysis of prehypertrophic chondrocyte removal of Sox9 demonstrated Sox9 was essential for hypertrophic chondrocyte development, while in vitro and ex vivo analyses showed AP-1 promotes chondrocyte hypertrophy. Sox9 and Jun co-bound and co-activated a Col10a1 enhancer in Sox9 and AP-1 motif-dependent manners consistent with their combined action promoting hypertrophic gene expression. Together, the data support a model where AP-1-family members promote Sox9-action in the transition of chondrocytes to a terminal hypertrophic program. Intersection of ChIP-seq data from Sox9 and AP-1 factor Jun, RNA-seq data from developing rib chondrocytes and Col10a1mCherry positive hypertrophic chondrocytes in neonatal mice to uncover regulation of Sox9 by AP-1 factors during chondrocyte hypertrophy.