Project description:Despite the well described role of non-cellular components of the tumor microenvironment (TME) in regulating tumor growth, the molecular events dictating expression and biological functions of key components of the TME remain elusive. Here, using pancreatic cancer (PC) models, we describe a novel mechanism through which the zinc finger transcription factor GLI2 in cancer associated fibroblasts (CAFs) induces expression of COL1A1, which is a major component of Collagen I and the most abundant collagen variant in the tumor milieu. Bulk and single nuclei RNA-seq showed that GLI2 expression in CAF strongly correlates with COL1A1 levels, fibrosis, and CAF activation. ChIP-qPCR and expression studies of the PC matrisome identified COL1A1 as the direct target of GLI2 in CAFs. We also provide evidence that GLI2 is an effector that mediates COL1A1 induction by transforming growth factor β1 (TGFβ1). RNA-seq analysis of PC cells treated with Collagen I revealed enrichment of chemotherapeutic gene expression profiles, which includes irinotecan resistance signature. Viability studies confirmed that Collagen I promotes irinotecan resistance in PC cells. Altogether, our results uncover a novel role for the TGFβ1-GLI2 axis within CAFs to modulate Collagen I expression and promote chemoresistance in PC cells. Our findings increase our understanding of the complex molecular network operating in the TME.
Project description:Communications between cardiomyocytes and fibroblasts in the heart are thought to occur through both secreted growth factors and via alterations in the structural properties of the extracellular matrix that each of the cell types helps generate. While perturbations in fibroblast activity are known to impact development of cardiomyocyte hypertrophy, the specific role played by collagen in this intercellular communication remains unknown. In this study we addressed this knowledge gap through differential regulation of collagen 1a2 using mouse hearts. The microarray assays reported here were carried out to assess the effects of collagen 1a2 ablation on cardiac transcriptional profiles.
Project description:We searched for candidate genes responsible for Epithelial-to-mesenchymal transition (EMT) by microarray analysis of cultured lung cancer cells with or without the property of spheroid formation. We found increased expression of a variety of adhesion molecules in cancer stem-like cells, including Collagen XVII. Further functional assays and signaling pathway were also investigated.
Project description:Pancreatic β cell dysfunction greatly contributes to the pathogenesis of type 2 diabetes. MiR-21 has been shown to be induced in the islets of glucose intolerant patients and type 2 diabetic mice. However, the role of miR-21 in the regulation of pancreatic β cell function remains largely elusive. In the current study, we studied the pathway by which miR-21 regulates glucose-stimulated insulin secretion utilizing mice lacking miR-21 in their β cells (miR-21βKO). We found that miR-21βKO mice developed glucose intolerance due to impaired glucose-stimulated insulin secretion. Mechanistic studies revealed that miR-21 enhances glucose uptake and subsequently promotes insulin secretion by up-regulating Glut2 expression in a miR-21-Pdcd4-AP-1 dependent pathway. Over-expression of Glut2 in knockout islets resulted in rescue of the impaired glucose-stimulated insulin secretion. Furthermore, we demonstrated that delivery of miR-21 into the pancreas of type 2 diabetic db/db mice is able to promote Glut2 expression and significantly reduce blood glucose level. Taking together, our results reveal that miR-21 in islet β cell promotes insulin secretion and support a role for miR-21 in the adaptation of pancreatic β cell function in type 2 diabetes.
Project description:RNA seq on primary pancreatic cancer (KPPC;Col1pdxKO cancer-collagen1 knockout) cells growing on collagen 1 homotrimers and heterotrimers. In this study, we identify that pancreatic cancer cells produce a unique Collagen1 homotrimer variant, in contrast to the Collagen1 heterotrimer produced by normal cells (such as fibroblasts). The variant forms of Collagen1 (homotrimer and heterotrimer) have distinct effects on cancer cell behaviors. We culture the pancreatic cancer cells on purified Collagen1 homotrimer and heterotrimer (as well as vehicle control) and examine the global changes of gene expression profile in cancer cells by variant Collagen1 subtypes.