Project description:The human breast is complex and comprised of multi-lineage and multi-structural elements. Recent work has shown that epithelial stem and progenitor cells use the collagen receptor Discoidin Domain Receptor 1 (DDR1) for differentiation into both basal and luminal cell lineages, which together are necessary for complex ductal-lobular morphogenesis. We developed a next-generation single cell derived organoid model that generates miniaturized breast tissue, to study how single stem cells can give rise to multiple cell types and compound tissue structures. We show that DDR1 activation triggers stem cell differentiation via RUNX1, in turn driving multilineage differentiation as well as complex ductal-lobular development. Mechanistically, DDR1 affects the interaction and expression of RUNX1 and its cofactor CBFβ, thereby regulating its activity. Together, these findings contribute to the current understanding of how the extracellular matrix component within the stem cell niche drives organogenesis and tissue regeneration.
Project description:Inversion of chromosome 16 is a consistent finding in patients with acute myeloid leukemia subtype M4 with eosinophilia (AML M4Eo), which generates a CBFB-MYH11 fusion gene. It is generally considered that CBFβ-SMMHC, the fusion protein encoded by CBFB-MYH11, is a dominant negative repressor of RUNX1. However, recent findings challenge the RUNX1-repression model for CBFβ-SMMHC mediated leukemogenesis. To definitively address the role of Runx1 in CBFB-MYH11 induced leukemia, we crossed conditional Runx1 knockout mice (Runx1f/f) with conditional Cbfb-MYH11 knockin mice (Cbfb+/56M). Upon Mx1-Cre activation in hematopoietic cells induced by poly (I:C) injection, all Mx1-CreCbfb+/56M mice developed leukemia in 5 months while no leukemia developed in Runx1f/fMx1-CreCbfb+/56M mice, and this effect was cell autonomous. Importantly, the abnormal myeloid progenitors (AMPs), a leukemia initiating cell population induced by Cbfb-MYH11 in the bone marrow, decreased and disappeared in Runx1f/fMx1-CreCbfb+/56M mice. RNA-seq analysis of AMP cells showed that genes associated with proliferation, differentiation blockage and leukemia initiation, were differentially expressed between Mx1-CreCbfb+/56M and Runx1f/fMx1-CreCbfb+/56M mice. In addition, with chromatin immunocleavage sequencing (ChIC-seq) assay, we observed a significant enrichment of RUNX1/CBFβ-SMMHC target genes in Runx1f/fMx1-CreCbfb+/56M cells, especially among down-regulated genes, suggesting that RUNX1 and CBFβ-SMMHC mainly function together as activators of gene expression through direct target gene binding. These data indicate that Runx1 is indispensable for Cbfb-MYH11 induced leukemogenesis by working together with CBFβ-SMMHC to regulate critical genes associated with the generation of a functional AMP population.
Project description:The CBFβ-MYH11 fusion generated by inv(16) aberration is proposed to block normal myeloid differentiation, but whether this subtype of leukemia cells is poised for an unique cell lineage remains unclear. Here, we surveyed the functional consequences of CBFβ-MYH11 in inv(16) patient blasts and two inducible systems by multi-omics profiling. The primary inv(16) cells stay closer with megakaryocyte and erythrocyte lineages along the cell differentiation trajectory, and share common transcriptomic signatures and epigenetic determiners. Using in vitro differentiation systems, we reveal that CBFβ-MYH11 knockdown establishes normal endomitosis-related processes, which are crucial for megakaryocyte maturation. Two pivotal regulators, GATA2 and KLF1, are identified to complementally occupy RUNX1 binding sites upon the fusion protein knockdown. Overexpression of GATA2 partly restores megakaryocyte directed differentiation suppressed by CBFβ-MYH11, and additional factors like KLF1 and EGR1 might be required to coordinately prevent CFB-MYH11 leukemogenesis. Together, our findings suggest that in inv(16) leukemia, the CBFβ-MYH11 fusion inhibits primed megakaryopoiesis by interfering with a balanced transcriptional program involving GATA2 and KLF1.
Project description:Examination of effect of stable DDR1 knockdown by shRNA on transcriptional profile in BXPC3 cell line to understand role of DDR1 in tumorigenesis. Transcriptional profiles of parental BXPC3 cell line was compared to BXPC3 cells stably transfected with non-target shRNA or DDR1 shRNA, N=3 for each condition.
Project description:Polycomb activity is frequently altered in acute leukaemia through mutation or deletion of Polycomb Repressive Complex (PRC) components. Alterations in PRC-interacting factors such as the Core Binding Factor (CBF) complex should also affect leukemia biology, even if PRC composition is normal. We report that the acute myeloid leukemia (AML)-associated CBFβ-SMMHC fusion oncoprotein physically interacts with the PRC1 complex, and that these factors co-localize across the AML genome in a PRC2-independent manner. Depletion of CBFβ-SMMHC caused increases in genome-wide PRC1 binding and an altered association between PRC1 and RUNX1. Overall, PRC1 was more likely to be associated with active genes. CBFβ-SMMHC depletion had variable transcriptional effects, including significant reductions in expression of PRC1-bound ribosomal loci. Our results expand on the recently reported localized effect of CBFβ-SMMHC on RUNX1-mediated recruitment of PRC1 at MYC enhancer elements, providing evidence that the oncoprotein diversely affects Polycomb recruitment and transcriptional regulation across the entire AML genome.
Project description:Examination of effect of stable DDR1 knockdown by shRNA on transcriptional profile in BXPC3 cell line to understand role of DDR1 in tumorigenesis.
Project description:As the most common degenerative joint disease, osteoarthritis (OA) contributes significantly to pain and disability during aging. Several genes of interest involved in articular cartilage damage in OA have been identified. However, the direct causes of OA are poorly understood. Evaluating the public human RNA-seq dataset showed that Cbfβ, (subunit of a heterodimeric Cbfβ/Runx1,Runx2, or Runx3 complex) expression is decreased in the cartilage of patients with OA. Here, we found that the chondrocyte-specific deletion of Cbfβ in tamoxifen-induced Cbfβf/fCol2α1-CreERT mice caused a spontaneous OA phenotype, worn articular cartilage, increased inflammation, and osteophytes. RNA-sequencing analysis showed that Cbfβ deficiency in articular cartilage resulted in reduced cartilage regeneration, increased canonical Wnt signaling and inflammatory response, and decreased Hippo/YAP signaling and TGF-β signaling. Immunostaining and western blot validated these RNA-seq analysis results. ACLT surgery-induced OA decreased Cbfβ and Yap expression and increased active β-catenin expression in articular cartilage, while local AAV-mediated Cbfβ overexpression promoted Yap expression and diminished active β-catenin expression in OA lesions. Remarkably, AAV-mediated Cbfβ overexpression in knee joints of mice with OA showed the significant protective effect of Cbfβ on articular cartilage in the ACLT OA mouse model. Overall, this study, using loss-of-function and gain-of-function approaches, uncovered that low expression of Cbfβ may be the cause of OA. Moreover, Local admission of Cbfβ may rescue and protect OA through decreasing Wnt/β-catenin signaling, and increasing Hippo/Yap signaling and TGFβ/Smad2/3 signaling in OA articular cartilage, indicating that local Cbfβ overexpression could be an effective strategy for treatment of OA. Using unbiased genome-wide RNA-seq data from Cbfβf/f;Col2α1-Cre hip joint articular cartilage and Cbfβf/f;Aggrecan-cre knee joint articular cartilage and their controls, we examined Cbfβ-mediated transcriptional targets for articular cartilage regeneration in OA.
Project description:Transcriptional regulation is critically involved in colorectal cancer (CRC) pathogenesis, the mechanism of which remains incompletely understood. Here, we report that core-binding factor β (CBFβ) is commonly upregulated in human colorectal cancer and is associated with the survival rate of CRC patients. Immunohistochemistry (IHC) analysis of RUNX1-3 expression in CRC patients and other in vitro data revealed that CBFβ promotes cell proliferation and liver metastasis in a RUNX2-dependent way. Transcriptome sequencing, ChIP-seq and promoter-binding experiments demonstrated that the CBFβ/RUNX2 complex could activate the transcription of OPN, FAM129A and UPP1. Furthermore, CBFβ significantly promoted tumor growth and lung metastasis in a mouse xenograft model and an orthotopic liver metastasis model of CRC. Additionally, we identified that tumor-suppressive miR-143/145 could synergistically target CBFβ by specifically binding to its 3’-UTR region. An inverse correlation between miR-143/145 and CBFβ was verified in CRC patients. Our results represent the first report describing a mechanistic role for CBFβ-RUNX2 in the transcriptional activation of OPN, FAM129A and UPP1 in controlling colorectal cancer development, which may offer prognostic and therapeutic opportunities.
Project description:Transcriptional regulation is critically involved in colorectal cancer (CRC) pathogenesis, the mechanism of which remains incompletely understood. Here, we report that core-binding factor β (CBFβ) is commonly upregulated in human colorectal cancer and is associated with the survival rate of CRC patients. Immunohistochemistry (IHC) analysis of RUNX1-3 expression in CRC patients and other in vitro data revealed that CBFβ promotes cell proliferation and liver metastasis in a RUNX2-dependent way. Transcriptome sequencing, ChIP-seq and promoter-binding experiments demonstrated that the CBFβ/RUNX2 complex could activate the transcription of OPN, FAM129A and UPP1. Furthermore, CBFβ significantly promoted tumor growth and lung metastasis in a mouse xenograft model and an orthotopic liver metastasis model of CRC. Additionally, we identified that tumor-suppressive miR-143/145 could synergistically target CBFβ by specifically binding to its 3’-UTR region. An inverse correlation between miR-143/145 and CBFβ was verified in CRC patients. Our results represent the first report describing a mechanistic role for CBFβ-RUNX2 in the transcriptional activation of OPN, FAM129A and UPP1 in controlling colorectal cancer development, which may offer prognostic and therapeutic opportunities.
Project description:Mammary morphogenesis is an orchestrated process involving differentiation, proliferation and organization of cells to form a bi-layered epithelial network of ducts and lobules embedded in storm tissue. We have engineered a 3D biomimetic human breast that makes it possible to study how stem cell fate decisions translate to tissue-level structure and functions. Using this advancement, we describe the mechanism by which breast epithelial cells build a complex three-dimensional, multi-lineage tissue by signaling through the collagen receptor DDR1. DDR1 induces stem cells to differentiate into basal cells, which in turn stimulate luminal progenitor cells to differentiate and form lobules via Notch signaling. These findings demonstrate how human breast tissue regeneration is triggered by transmission of signals from the extracellular matrix through an epithelial bilayer to coordinate structural changes that form a complex ductal-lobular network. More broadly, these findings suggest that DDR1 may coordinate collagen and Notch signaling to regulate multi-lineage differentiation and morphogenesis across diverse tissues.