Project description:In the current work, we add to the understanding of differentiated-cell-derived tumorigenesis by demonstrating that simultaneous loss of SMAD4 and activation of the WNT pathway triggers stem cell properties and adenoma formation in the differentiated epithelium. Under normal conditions, SMAD4 loss does not immediately affect the normal tissue homeostasis in the intestine. However, after approximately 6 months, adenomas will develop and feature elevated WNT signaling, suggesting that SMAD4 loss predisposes to WNT-driven tumors. Interestingly, ectopic elevation of WNT in the context of a SMAD4 mutant background triggers stem cell activity and adenoma formation in the differentiated epithelium. Thus Smad4 functions to suppress villus cells from re-entering the cell cycle and functioning as stem cells upon exposure to high levels of WNT. Thus, we report a new mechanism through which differentiated cells can contribute to tumor formation.
Project description:The development of metastasis severely reduces the life expectancy of patients with colorectal cancer (CRC). Loss of SMAD4 is a key event in late-stage CRC resulting in the progression to metastatic CRC in 10-30% of the cases. However, the biological processes and underlying molecular mechanisms that it affects are not fully understood. Here, we applied a multi-omics approach to a CRC tumor progression organoid model that faithfully reflects the metastasis-inducing effects of SMAD4 inactivation. We show that loss of SMAD4 results in loss of differentiation and activation of pro-migratory and cell proliferation processes, which is accompanied by the disruption of several key oncogenic pathways, including the TGFB, WNT, and VEGF pathways. In addition, SMAD4 inactivation leads to increased secretion of proteins that are known to be involved in a variety of pro-metastatic processes. Finally, we show that one of the factors that is specifically secreted by metastatic organoids – DKK3 – reduces the anti-tumor effects of natural killer cells (NKCs). Altogether, our data provides promising new targets concerning the role of SMAD4 perturbation and metastatic disease in CRC.
Project description:Constitutive Wnt activation upon loss of Adenoma polyposis coli (APC) acts as main driver of colorectal cancers (CRC). Targeting Wnt signaling has proven difficult because the pathway is crucial for homeostasis and stem cell renewal. To distinguish oncogenic from physiologic Wnt activity, we have performed transcriptome and proteome profiling in isogenic human colon organoids. Culture in the presence or absence of exogenous ligand allowed us to discriminate receptor-mediated signaling from the effects of CRISPR/Cas9 induced APC loss. We could catalogue two non-overlapping molecular signatures that were stable at distinct levels of stimulation. Newly identified markers for normal stem/progenitor cells and adenomas were validated by immunohistochemistry and flow cytometry. We found that oncogenic Wnt signals are associated with good prognosis in tumors of the consensus molecular subtype 2 (CMS2). In contrast, receptor-mediated signaling was linked to CMS4 tumors and poor prognosis. Together, our data represent a valuable resource for biomarkers that allow more precise stratification of Wnt responses in CRC.
Project description:The development of metastasis severely reduces the life expectancy of patients with colorectal cancer (CRC). Loss of SMAD4 is a key event in late-stage CRC resulting in the progression to metastatic CRC in 10-30% of the cases. However, the biological processes and underlying molecular mechanisms that it affects are not fully understood. Here, we applied a multi-omics approach to a CRC tumor progression organoid model that faithfully reflects the metastasis-inducing effects of SMAD4 inactivation. We show that loss of SMAD4 results in loss of differentiation and activation of pro-migratory and cell proliferation processes, which is accompanied by the disruption of several key oncogenic pathways, including the TGFB, WNT, and VEGF pathways. In addition, SMAD4 inactivation leads to increased secretion of proteins that are known to be involved in a variety of pro-metastatic processes. Finally, we show that one of the factors that is specifically secreted by metastatic organoids – DKK3 – reduces the anti-tumor effects of natural killer cells (NKCs). Altogether, our data provides promising new targets concerning the role of SMAD4 perturbation and metastatic disease in CRC.
Project description:Loss of SMAD4 is associated with worse outcomes for colorectal cancer patients. We used gene ontology and data driven approach to identify a SMAD4-modulated profile and test its association with patient outcome. Using a discovery dataset of 250 colorectal cancer patients, we analyzed expression of BMP/Wnt target genes for association with SMAD4 expression. Promoters of the BMP/Wnt genes were interrogated for SMAD-binding elements. 15 genes were implicated and three tested for modulation by SMAD4 in patient-derived colorectal cancer tumoroids. Expression of the 15 genes was used for unsupervised hierarchical clustering of a training dataset and two resulting clusters modeled in a centroid model.
Project description:The APC (Adenomatous Polyposis Coli) gene encodes a large multidomain protein that plays an integral role in the Wnt/beta-catenin signaling pathway. The loss-of-function mutation in APC is considered the earliest genetic alteration in the course of adenoma-carcinoma sequence of colorectal cancer progression, and the resulting constitutive activation of Wnt/beta-catenin signaling is required for the maintenance of advanced colorectal cancer. In order to identify genes affected by loss of Apc function, we performed transcription profiling of mouse small intestinal tissues comparing polyps with normal mucosa of Apc+/Delta716 mice. We isolated total RNA from intestinal polyps and normal intestinal mucosa from 3 individual Apc+/Delta716 mice. Total RNA samples were then employed to perform microarray analysis (Agilent Whole Mouse Genome Microarray Ver. 2.0, 4x44K).
Project description:Stable activation of the WNT signaling effector beta-catenin (CTNNB1(ex3) in ovarian granulosa cells results in the formation of premalignant lesions that develop into granulosa cell tumors (GCTs) spontaneously later in life. Loss of the tumor suppressor gene Pten accelerates GCT formation in the CTNNB1 strain. Conversely, expression of oncogenic KRASG12D causes the dramatic arrest of proliferation, differentiation and apoptosis in granulosa cells, and consequently, small abnormal follicle-like structures devoid of oocytes accumulate in the ovary. Because of the potent anti-proliferative effects of KRASG12D in granulosa cells, we sought to determine if KRASG12D would block precancerous lesion and tumor formation in follicles of the CTNNB1 mutant mice. Unexpectedly, transgenic Ctnnb1;Kras mutant mice developed early-onset GCTs leading to premature death in a manner similar to theCtnnb1;Pten mutant mice. Moreover, the GCTs in the Ctnnb1;Kras mutant mice exhibited increased GC proliferation, decreased apoptosis and impaired differentiation. Microarray and RT-PCR analyses revealed that ovaries from mice expressing dominant-stable CTNNB1 with either Pten loss or KRAS activation were unpredictably similar. Specifically, gene regulatory processes induced by CTNNB1 were mostly enhanced by either KRAS activation or Pten loss in remarkably similar patterns and degree. Furthermore, the concomitant activation of CTNNB1 and KRAS in Sertoli cells resulted in the development of granulosa cell tumors of the testis. RT-PCR studies showed a partial overlap in gene regulatory processes associated with tumor development in the ovary and testis. Together, these results suggest that KRAS activation and Pten loss induce GCT development from premalignant lesions via highly similar molecular mechanisms. four samples: average of two wild type samples (previously submitted as GSM403220 and GSM403221), beta-Catenin constitutively active mutant, beta-Catenin;Pten double mutant, and beta-Catenin;Kras(G12D) double mutant
Project description:Lung cancer remains the leading cause of cancer death. Genome sequencing of lung tumors from patients with Squamous Cell Carcinoma has identified SMAD4 to be frequently mutated. Here we used a novel mouse model to determine the molecular mechanisms regulated by loss of Smad4 which lead to lung cancer progression. Mice with ablation of Pten and Smad4 in airway epithelium developed metastatic adenosquamous tumors. Comparative transcriptomic and in vivo cistromic analyses determined that loss of PTEN and SMAD4 resulted in activation of the ELF3 and the ErbB2 pathway due to decreased ERRFI1M-bM-^@M-^Ys expression, a negative regulator of ERBB2 in mice and human cells. The combinatorial inhibition of ErbB2 and Akt signaling attenuated tumor progression and cell invasion, respectively. Expression profiles analysis of human lung tumors substantiated the importance of the ErbB2/Akt/ELF3 signaling pathway as both prognostic biomarkers and therapeutic drug targets for treating lung cancer. Examination of genome-wide SMAD4 binding in 7-month-old Ptend/d mouse lung.
Project description:Sustained cardiac stress promotes the transition from an adaptive response to heart failure. Understanding of mechanisms governing this transition will assist in identifying targets that prevent this progression. Our study revealed age-specific transcriptional functions mediated by KLF15 that are crucial for cardiac homeostasis. We report that postnatally, KLF15 continuously activates cardiac metabolism, but represses pathological, hypertrophic pathways associated with cardiomyocyte de-differentiation and endothelial cell (EC) remodeling in an age-dependent manner. Our integrative genomic and transcriptomic analyses identified novel target genes directly bound, and either activated or repressed by KLF15 in vivo in the adult heart. We identified a cooperative program inducing aberrant EC remodeling, caused by a reduction of KLF15 and a concomitant activation of Wnt signaling. Within this program, we further identified a so far uncharacterized cardiac gene - Shisa3, which is expressed in the developing heart and is upregulated in cardiac hypertrophy, ischemia and failure. Importantly, we demonstrate that the KLF15- and Wnt co-dependent, SHISA regulation occurs also in the human myocardium. Altogether, our results unraveled and characterized a previously unknown cardiac gene Shisa3, and attributed its significance to EC homeostasis of the adult heart, controlled by KLF15-Wnt dynamics. Purpose: The aim of this study was to compare transcriptome profiles (RNA-seq) of heart tissue with a WT or KO Klf15 locus at different murine ages - postnatal day10 (p10), 4-week-old and 20-week-old mice. Methods: Cardiac tissue total RNA profiles for different groups were obtained using deep sequencing, in triplicates, using Illumina HiSeq4000. The sequence reads that passed quality filters were analyzed at the transcript isoform level with TopHat, followed by DESeq2. qPCR validation was performed using TaqMan and SYBR Green assays. Conclusions: Our study represents the first detailed analysis of the processes triggered upon Klf15 loss in hearts of different murine postnatal ages, which was so far not investigated. We report that this Klf15 loss first triggers Wnt canonical pathway activation, followed by activation of the non-canonical Wnt components, culminating in heart failure.
Project description:Somatic mutations in APC or CTNNB1 genes lead to aberrant Wnt signaling and colorectal cancer (CRC) initiation and progression. Activation of Wnt pathway leads to the formation of beta-catenin-T-cell factor/Lymphoid enhancer binding factor 1 (Tcf/Lef1) complexes that activate transcription of oncogenic target genes. Lef1 is the only member of the Tcf gene family that is not expressed in the normal intestine, but is induced during intestinal tumorigenesis. Thus, we wanted to assess the role of Lef1 using genetic mouse models of intestinal adenomas and scRNA-seq technology. Tumorigenesis was initiated by inducing Apc mutation in Lgr5+ stem cells. Intestinal EpCAM+ epithelial cells of Lgr5-CreERT;Apc fl/fl (LApc) mouse and Lgr5-CreERT;Apc fl/fl; Lef1 fl/fl (LApcL) mouse were used to analyze the effects of Lef1 deletion in intestinal adenoma cells. We used WT mice as a control to distinguish adenoma cells.