PDGF-BB modulates hematopoiesis and tumor angiogenesis by inducing erythropoietin production in stromal cells.
Ontology highlight
ABSTRACT: 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 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.
Project description:Anti-PDGF agents are routinely used as a key component in front-line therapy for the treatment of various cancers. However, molecular mechanisms underlying their impact on vascular remodeling in relation to the dose issue remain poorly understood. Here we show that in high PDGF-BB-producing tumors, anti-PDGF drugs significantly inhibited tumor growth and metastasis by preventing pericyte (PC) loss and vascular permeability. Surprisingly, the same anti-PDGF-BB drugs promoted tumor cell dissemination and metastasis in PDGF-BB-low-producing or negative tumors by ablating PCs from tumor vessels. At the molecular level, we show that the PDGFR-? signaling pathway in PCs mediated the opposing effects and persistent exposure of PCs to PDGF-BB led to marked downregulation of PDGFR-?. Inactivation of the PDGFR-? signaling system led to decreased levels of integrin ?1?1, resulted in impaired adhesion of PCs to collagen I, IV and laminin, two principal extracellular matrix components in blood vessels for interaction with these integrins. Our data suggest that tumor PDGF-BB levels may serve as an important biomarker for selection of tumor-bearing hosts for beneficial therapy and unsupervised practice of this group of drugs could potentially promote tumor invasion and metastasis. Pericytes were isolated and treated with PDGF-BB or control for 5 days.
Project description:Anti-PDGF agents are routinely used as a key component in front-line therapy for the treatment of various cancers. However, molecular mechanisms underlying their impact on vascular remodeling in relation to the dose issue remain poorly understood. Here we show that in high PDGF-BB-producing tumors, anti-PDGF drugs significantly inhibited tumor growth and metastasis by preventing pericyte (PC) loss and vascular permeability. Surprisingly, the same anti-PDGF-BB drugs promoted tumor cell dissemination and metastasis in PDGF-BB-low-producing or negative tumors by ablating PCs from tumor vessels. At the molecular level, we show that the PDGFR-β signaling pathway in PCs mediated the opposing effects and persistent exposure of PCs to PDGF-BB led to marked downregulation of PDGFR-β. Inactivation of the PDGFR-β signaling system led to decreased levels of integrin α1β1, resulted in impaired adhesion of PCs to collagen I, IV and laminin, two principal extracellular matrix components in blood vessels for interaction with these integrins. Our data suggest that tumor PDGF-BB levels may serve as an important biomarker for selection of tumor-bearing hosts for beneficial therapy and unsupervised practice of this group of drugs could potentially promote tumor invasion and metastasis.
Project description:Vascular pericytes, an important cellular component, in the tumor microenvironment, are often associated with tumor vasculatures and their functions in cancer invasion and metastasis are poorly understood. Here we show that PDGF-BB induces pericyte fibroblast transition (designated as PFT), which significantly contributes to tumor invasion and metastasis. Gain- and loss-of-function experiments demonstrate that the PDGF-BB-PDGFRβ signaling promotes PFT in vitro and in in vivo tumors. Genome-wide expression analysis indicates that PDGF-BB-activated pericytes acquire mesenchymal progenitor features. Pharmacological inhibition and genetic deletion of PDGFRβ ablate the PDGF-BB-induced PFT. Genetic tracing of pericytes with two independent mouse strains, i.e., TN-AP-CreERT2:R26R-tdTomato and NG2:R26R-tdTomato, shows that PFT cells gains stromal fibroblast and myofibroblast markers in tumors. Importantly, co-implantation of PFT cells with less-invasive tumor cells in mice markedly promotes tumor dissemination and invasion, leading to an increased number of circulating tumor cells (CTCs) and metastasis. Our findings reveal a novel mechanism of vascular pericytes in PDGF-BB-promoted cancer invasion and metastasis by inducing PFT and thus targeting PFT may offer a new treatment option of cancer metastasis. Pericytes were isolated and treated with PDGF-BB or control for 1 or 5 days
Project description:Glycolysis is a fundamental cellular process, yet its regulatory mechanisms remain incompletely understood. Here, we show that a subset of glucose transporter 1 (GLUT1/SLC2A1) co-endocytoses with platelet-derived growth factor (PDGF) receptor (PDGFR) upon PDGF-stimulation. LC-MS was used to characterize the isolates from cells stimulated with PDGF-BB-conjugated nanoparticles (endocytic vesicle fraction) or PDGF-BB plus unconjugated nanoparticles (control). Taken together, multiple glycolytic enzymes localize to these endocytosed PDGFR/GLUT1-containing vesicles adjacent to mitochondria. Contrary to current models, which emphasize the importance of glucose transporters on the cell surface, we find that PDGF-stimulated glucose uptake depends on receptor/transporter endocytosis. Our results suggest that growth factors generate glucose-loaded endocytic vesicles that deliver glucose to the glycolytic machinery in proximity to mitochondria, and argue for a new layer of regulation for glycolytic control governed by cellular membrane dynamics.
Project description:Vascular pericytes, an important cellular component, in the tumor microenvironment, are often associated with tumor vasculatures and their functions in cancer invasion and metastasis are poorly understood. Here we show that PDGF-BB induces pericyte fibroblast transition (designated as PFT), which significantly contributes to tumor invasion and metastasis. Gain- and loss-of-function experiments demonstrate that the PDGF-BB-PDGFRβ signaling promotes PFT in vitro and in in vivo tumors. Genome-wide expression analysis indicates that PDGF-BB-activated pericytes acquire mesenchymal progenitor features. Pharmacological inhibition and genetic deletion of PDGFRβ ablate the PDGF-BB-induced PFT. Genetic tracing of pericytes with two independent mouse strains, i.e., TN-AP-CreERT2:R26R-tdTomato and NG2:R26R-tdTomato, shows that PFT cells gains stromal fibroblast and myofibroblast markers in tumors. Importantly, co-implantation of PFT cells with less-invasive tumor cells in mice markedly promotes tumor dissemination and invasion, leading to an increased number of circulating tumor cells (CTCs) and metastasis. Our findings reveal a novel mechanism of vascular pericytes in PDGF-BB-promoted cancer invasion and metastasis by inducing PFT and thus targeting PFT may offer a new treatment option of cancer metastasis.
Project description:To explore global molecular changes in smooth muscle in response to PDGFR activation, primary human bladder smooth muscle cells were treated with 1 nM PDGF-BB (hereafter PDGF) for 0, 4 or 24 h. Total RNA were prepared, and analyzed using expression profiling, and subjected to bioinformatic and functional interrogation. To identify molecular signatures of bladder smooth muscle peturbed by PDGF, primary human bladder smooth muscle cells were treated with 1 nM PDGF-BB (hereafter PDGF) for 0, 4 or 24 h.
Project description:To explore global molecular changes in smooth muscle in response to PDGFR activation, primary human bladder smooth muscle cells were treated with 1 nM PDGF-BB (hereafter PDGF) for 0, 4 or 24 h. Total RNA were prepared, and analyzed using expression profiling, and subjected to bioinformatic and functional interrogation.
Project description:Vascular stability and tone are maintained by contractile smooth muscle cells (VSMCs). However, injury-induced growth factors stimulate a contractile-synthetic phenotypic modulation which increases susceptibility to abdominal aortic aneurysm (AAA). As a regulator of embryonic VSMC differentiation, we hypothesised that Thymosin β4 (Tβ4) may function to maintain healthy vasculature throughout postnatal life. This was supported by the identification of an interaction with Low density lipoprotein receptor related protein 1 (LRP1), an endocytic regulator of PDGF-BB signalling and VSMC proliferation. LRP1 variants have been implicated by genome-wide association studies with risk of AAA and other arterial diseases. T4-null mice displayed aortic VSMC and elastin defects, phenocopying LRP1 mutants, and their compromised vascular integrity predisposed to Angiotensin II-induced aneurysm formation. Aneurysmal vessels were characterised by enhanced VSMC phenotypic modulation and augmented platelet-derived growth factor (PDGF) receptor (PDGFR)β signalling. In vitro, enhanced sensitivity to PDGF-BB, upon loss of Tβ4, associated with dysregulated endocytosis, with increased recycling and reduced lysosomal targeting of LRP1-PDGFRβ. Accordingly, the exacerbated aneurysmal phenotype in T4-null mice was rescued upon treatment with the PDGFRβ antagonist, Imatinib. Our study identifies Tβ4 as a key regulator of LRP1 for maintaining vascular health and provides insights into the mechanisms of growth factor-controlled VSMC phenotypic modulation underlying aortic disease progression.