Showing papers on "Hepatocyte growth factor published in 2013"
TL;DR: Evolving areas of interest in stellate cell biology seek to understand mechanisms of their clearance during fibrosis resolution by either apoptosis, senescence, or reversion, and their contribution to hepatic stem cell amplification, regeneration, and hepatocellular cancer.
Abstract: Hepatic stellate cells are resident perisinusoidal cells distributed throughout the liver, with a remarkable range of functions in normal and injured liver. Derived embryologically from septum transversum mesenchyme, their precursors include submesothelial cells that invade the liver parenchyma from the hepatic capsule. In normal adult liver, their most characteristic feature is the presence of cytoplasmic perinuclear droplets that are laden with retinyl (vitamin A) esters. Normal stellate cells display several patterns of intermediate filaments expression (e.g., desmin, vimentin, and/or glial fibrillary acidic protein) suggesting that there are subpopulations within this parental cell type. In the normal liver, stellate cells participate in retinoid storage, vasoregulation through endothelial cell interactions, extracellular matrix homeostasis, drug detoxification, immunotolerance, and possibly the preservation of hepatocyte mass through secretion of mitogens including hepatocyte growth factor. During liver injury, stellate cells activate into alpha smooth muscle actin-expressing contractile myofibroblasts, which contribute to vascular distortion and increased vascular resistance, thereby promoting portal hypertension. Other features of stellate cell activation include mitogen-mediated proliferation, increased fibrogenesis driven by connective tissue growth factor, and transforming growth factor beta 1, amplified inflammation and immunoregulation, and altered matrix degradation. Evolving areas of interest in stellate cell biology seek to understand mechanisms of their clearance during fibrosis resolution by either apoptosis, senescence, or reversion, and their contribution to hepatic stem cell amplification, regeneration, and hepatocellular cancer.
713 citations
TL;DR: These studies reveal that heparanase helps drive exosome secretion, altersExosome composition, and facilitates production of exosomes that impact both tumor and host cell behavior, thereby promoting tumor progression.
278 citations
TL;DR: Findings suggest that MSCs secrete bioactive factors, including HGF and VEGF, that stimulate neurogenesis and improve outcomes of TBI in a rat model as well as the therapeutic potential of the cultured MSC secretome in experimental TBI.
Abstract: Bone-marrow-derived human MSCs (mesenchymal stem cells) support repair when administered to animals with TBI (traumatic brain injury) in large part through secreted trophic factors. We directly tested the ability of the culture medium (or secretome) collected from human MSCs under normoxic or hypoxic conditions to protect neurons in a rat model of TBI. Concentrated conditioned medium from cultured human MSCs or control medium was infused through the tail vein of rats subjected to TBI. We have demonstrated that MSCs cultured in hypoxia were superior to those cultured in normoxia in inducing expression of both HGF (hepatocyte growth factor) and VEGF (vascular endothelial growth factor) in the cultured medium. We showed further that rats treated with the secretome from both normoxic- and hypoxic-preconditioned MSCs performed significantly better than the controls in both motor and cognitive functional test. Subsequent post-mortem evaluation of brain damage at the 4-day time point confirmed that both normoxic- and hypoxic-preconditioned MSC secretome-treated rats had significantly greater numbers of newly forming neurons, but significantly less than the controls in brain damaged volume and apoptosis. The TBI rats treated with hypoxic-preconditioned MSC secretome performed significantly better in both motor and cognitive function tests and neurogenesis, and had significantly less brain damage than the TBI rats treated with the normoxic-preconditioned MSC secretome. Collectively, these findings suggest that MSCs secrete bioactive factors, including HGF and VEGF, that stimulate neurogenesis and improve outcomes of TBI in a rat model. Hypoxic preconditioning enhances the secretion of these bioactive factors from the MSCs and the therapeutic potential of the cultured MSC secretome in experimental TBI.
242 citations
TL;DR: In conclusion, intramyocardial transplantation of purified human pericytes promotes functional and structural recovery, attributable to multiple mechanisms involving paracrine effects and cellular interactions.
Abstract: Human microvascular pericytes (CD146(+)/34(-)/45(-)/56(-)) contain multipotent precursors and repair/regenerate defective tissues, notably skeletal muscle. However, their ability to repair the ischemic heart remains unknown. We investigated the therapeutic potential of human pericytes, purified from skeletal muscle, for treating ischemic heart disease and mediating associated repair mechanisms in mice. Echocardiography revealed that pericyte transplantation attenuated left ventricular dilatation and significantly improved cardiac contractility, superior to CD56+ myogenic progenitor transplantation, in acutely infarcted mouse hearts. Pericyte treatment substantially reduced myocardial fibrosis and significantly diminished infiltration of host inflammatory cells at the infarct site. Hypoxic pericyte-conditioned medium suppressed murine fibroblast proliferation and inhibited macrophage proliferation in vitro. High expression by pericytes of immunoregulatory molecules, including interleukin-6, leukemia inhibitory factor, cyclooxygenase-2, and heme oxygenase-1, was sustained under hypoxia, except for monocyte chemotactic protein-1. Host angiogenesis was significantly increased. Pericytes supported microvascular structures in vivo and formed capillary-like networks with/without endothelial cells in three-dimensional cocultures. Under hypoxia, pericytes dramatically increased expression of vascular endothelial growth factor-A, platelet-derived growth factor-β, transforming growth factor-β1 and corresponding receptors while expression of basic fibroblast growth factor, hepatocyte growth factor, epidermal growth factor, and angiopoietin-1 was repressed. The capacity of pericytes to differentiate into and/or fuse with cardiac cells was revealed by green fluorescence protein labeling, although to a minor extent. In conclusion, intramyocardial transplantation of purified human pericytes promotes functional and structural recovery, attributable to multiple mechanisms involving paracrine effects and cellular interactions.
220 citations
TL;DR: Evidence is emerging for identification of aberrant MET activity biomarkers and selection of patient subpopulations that may benefit from targeted MET and HGF inhibitor treatment.
188 citations
TL;DR: In this article, the potential of diabetic ASCs to promote wound healing with respect to non-diabetic ones was evaluated in the treatment of diabetic ulcers, and it was shown that diabetic ASC showed decreased proliferative potential and migration.
Abstract: Adipose tissue-derived stem cells (ASCs) are gaining increasing consideration in tissue repair therapeutic application. Recent evidence indicates that ASCs enhance skin repair in animal models of impaired wound healing. To assess the therapeutic activity of autologous vs. allogeneic ASCs in the treatment of diabetic ulcers, we functionally characterized diabetic ASCs and investigated their potential to promote wound healing with respect to nondiabetic ones. Adipose tissue-derived cells from streptozotocin-induced type 1 diabetic mice were analyzed either freshly isolated as stromal vascular fraction (SVF), or following a single passage of culture (ASCs). Diabetic ASCs showed decreased proliferative potential and migration. Expression of surface markers was altered in diabetic SVF and cultured ASCs, with a reduction in stem cell marker-positive cells. ASCs from diabetic mice released lower amounts of hepatocyte growth factor, vascular endothelial growth factor (VEGF)-A, and insulin-like growth factor-1, growth factors playing important roles in skin repair. Accordingly, the supernatant of diabetic ASCs manifested reduced capability to promote keratinocyte and fibroblast proliferation and migration. Therapeutic potential of diabetic SVF administered to wounds of diabetic mice was blunted as compared with cells isolated from nondiabetic mice. Our data indicate that diabetes alters ASC intrinsic properties and impairs their function, thus affecting therapeutic potential in the autologous treatment for diabetic ulcers.
182 citations
TL;DR: The biology of MET is summarized as well as its therapeutic inhibition in lung cancer, and a number of compounds against MET/HGF in clinical trials that have been shown to be active in lung cancers are reviewed.
Abstract: Lung cancer is a heterogeneous group of disorders that is now being subdivided into molecular subtypes with dedicated targeted therapies. The MET receptor tyrosine kinase has been identified as aberrantly overexpressed, potentially having activating mutations, and amplified in certain subsets of lung cancers. The ligand hepatocyte growth factor (HGF) can also be overexpressed in lung cancer or expressed in stroma, and both the MET receptor and the HGF ligand can be targets for therapeutics, especially in lung cancer. Activation of MET leads to a plethora of biochemical and biologic changes both in normal and cancerous cells. Preclinically, it has been shown that silencing or inactivating MET leads to decreased viability of cancer cells. There are a number of compounds against MET/HGF in clinical trials that have been shown to be active in lung cancers. This review will summarize the biology of MET as well as its therapeutic inhibition in lung cancer.
180 citations
TL;DR: Examination of liver regeneration from the perspective that BM SPCs that have been recruited to the liver, rather than mature LSECs, drive liver regeneration finds that bone marrow progenitor cells of L SECs, which are rich in HGF, are recruited toThe liver after injury.
Abstract: Liver sinusoidal endothelial cells (LSECs) have long been noted to contribute to liver regeneration after liver injury. In normal liver, the major cellular source of HGF is the hepatic stellate cell, but after liver injury, HGF expression has been thought to increase markedly in proliferating LSECs. However, emerging data suggest that even after injury, LSEC expression of HGF does not increase greatly. In contrast, bone marrow progenitor cells of LSECs (BM SPCs), which are rich in HGF, are recruited to the liver after injury. This Review examines liver regeneration from the perspective that BM SPCs that have been recruited to the liver, rather than mature LSECs, drive liver regeneration.
173 citations
TL;DR: Basic scientific evidence is provided to support the use of PRP to treat injured tendons because PRP can reduce inflammation and thereby reduce the associated pain caused by high levels of PGE2.
Abstract: Platelet-rich plasma (PRP) containing hepatocyte growth factor (HGF) and other growth factors are widely used in orthopaedic/sports medicine to repair injured tendons. While PRP treatment is reported to decrease pain in patients with tendon injury, the mechanism of this effect is not clear. Tendon pain is often associated with tendon inflammation, and HGF is known to protect tissues from inflammatory damages. Therefore, we hypothesized that HGF in PRP causes the anti-inflammatory effects. To test this hypothesis, we performed in vitro experiments on rabbit tendon cells and in vivo experiments on a mouse Achilles tendon injury model. We found that addition of PRP or HGF decreased gene expression of COX-1, COX-2, and mPGES-1, induced by the treatment of tendon cells in vitro with IL-1β. Further, the treatment of tendon cell cultures with HGF antibodies reduced the suppressive effects of PRP or HGF on IL-1β-induced COX-1, COX-2, and mPGES-1 gene expressions. Treatment with PRP or HGF almost completely blocked the cellular production of PGE2 and the expression of COX proteins. Finally, injection of PRP or HGF into wounded mouse Achilles tendons in vivo decreased PGE2 production in the tendinous tissues. Injection of platelet-poor plasma (PPP) however, did not reduce PGE2 levels in the wounded tendons, but the injection of HGF antibody inhibited the effects of PRP and HGF. Further, injection of PRP or HGF also decreased COX-1 and COX-2 proteins. These results indicate that PRP exerts anti-inflammatory effects on injured tendons through HGF. This study provides basic scientific evidence to support the use of PRP to treat injured tendons because PRP can reduce inflammation and thereby reduce the associated pain caused by high levels of PGE2.
160 citations
TL;DR: Results suggest that overexpression of TGF-α through induction of EGFR–MET interaction contributes to cetuximab resistance in colorectal cancer cells.
Abstract: Purpose: Although cetuximab, an anti-EGF receptor (EGFR) monoclonal antibody, is an effective treatment for patients with KRAS wild-type metastatic colorectal cancer (mCRC), its clinical use is limited by onset of resistance. Experimental Design: We characterized two colorectal cancer models to study the mechanisms of acquired resistance to cetuximab. Results: Following chronic treatment of nude mice bearing cetuximab-sensitive human GEO colon xenografts, cetuximab-resistant GEO (GEO-CR) cells were obtained. In GEO-CR cells, proliferation and survival signals were constitutively active despite EGFR inhibition by cetuximab treatment. Whole gene expression profiling identified a series of genes involved in the hepatocyte growth factor (HGF)-MET–dependent pathways, which were upregulated in GEO-CR cells. Furthermore, activated, phosphorylated MET was detected in GEO-CR cells. A second colorectal cancer cell line with acquired resistance to cetuximab was obtained (SW48-CR). Inhibition of MET expression by siRNA restored cetuximab sensitivity in GEO-CR and SW48-CR cells, whereas exogenous activation of MET by HGF stimulation in cetuximab-sensitive GEO and SW48 cells induced resistance to cetuximab. Treatment of GEO-CR and SW48-CR cells with PHA665752, a selective MET inhibitor, inhibited cell growth, proliferation, and survival signals and impaired cancer cell migration. Overexpression of TGF-α, a specific EGFR ligand, was involved in the acquisition of cetuximab resistance in GEO-CR and SW48-CR cells. In fact, TGF-α overexpression induced the EGFR–MET interaction, with subsequent MET phosphorylation and activation of MET downstream effectors in GEO-CR and SW48-CR cells. Conclusions: These results suggest that overexpression of TGF-α through induction of EGFR–MET interaction contributes to cetuximab resistance in colorectal cancer cells. The combined inhibition of EGFR and MET receptor could represent a strategy for preventing and/or overcoming cetuximab resistance in patients with colorectal cancer. Clin Cancer Res; 19(24); 6751–65. ©2013 AACR .
130 citations
TL;DR: Findings suggest that MSCs may have a role in restoring damaged ovarian function and could be useful for regenerative medicine.
TL;DR: It is found that the proliferation of MHCC97L and Hep3B cells was significantly promoted by treatment with conditioned medium from H-CAFs, and that HGF plays a key role in HCC proliferation induced by H- CAFs.
Abstract: Cancer-associated fibroblasts (CAFs) are reported to support tumorigenesis by stimulating angiogenesis, cancer cell proliferation, and invasion in most solid tumors. However, the roles of CAFs in the liver cancer microenvironment have not been thoroughly studied. In our previous study, we successfully isolated CAFs from hepatocellular carcinoma (HCC) (H-CAFs) and proved that H-CAFs suppressed the activation of NK cells and thereby created favorable conditions for HCC progression. In our present study, we found that the proliferation of MHCC97L and Hep3B cells was significantly promoted by treatment with conditioned medium from H-CAFs. Pathological analysis also revealed that H-CAFs increased the proportion of Ki-67 (+) malignant cells and prevented them from undergoing necrosis. Moreover, the concentration of hepatocyte growth factor (HGF) cytokine in the conditioned medium of H-CAFs was higher than conditioned medium from normal skin fibroblasts (NSFs). Anti-HGF significantly reduced the proliferation-promoting capability of H-CAFs. In addition, we found that the abundance of H-CAFs correlated positively with tumor size. These results indicate that H-CAFs are an important factor for promoting the growth of HCC in vitro and in vivo, and that HGF plays a key role in HCC proliferation induced by H-CAFs.
TL;DR: Intratracheal transplantation of human UCB derived MSCs time-dependently attenuated hyperoxia-induced lung injury in neonatal rats, showing significant protection only in the early but not in the late phase of inflammation.
Abstract: Intratracheal transplantation of human umbilical cord blood (UCB)-derived mesenchymal stem cells (MSCs) attenuates the hyperoxia-induced neonatal lung injury. The aim of this study was to optimize the timing of MSCs transplantation. Newborn Sprague-Dawley rats were randomly exposed to hyperoxia (90% for 2 weeks and 60% for 1 week) or normoxia after birth for 21 days. Human UCB-derived MSCs (5×105 cells) were delivered intratracheally early at postnatal day (P) 3 (HT3), late at P10 (HT10) or combined early+late at P3+10 (HT3+10). Hyperoxia-induced increase in mortality, TUNEL positive cells, ED1 positive alveolar macrophages, myeloperoxidase activity and collagen levels, retarded growth and reduced alveolarization as evidenced by increased mean linear intercept and mean alveolar volume were significantly better attenuated in both HT3 and HT3+10 than in HT10. Hyperoxia-induced up-regulation of both cytosolic and membrane p47phox indicative of oxidative stress, and increased inflammatory markers such as tumor necrosis factor-α, interleukin (IL) -1α, IL-1β, IL-6, and transforming growth factor-β measured by ELISA, and tissue inhibitor of metalloproteinase-1, CXCL7, RANTES, L-selectin and soluble intercellular adhesion molecule-1 measured by protein array were consistently more attenuated in both HT3 and HT3+10 than in HT10. Hyperoxia-induced decrease in hepatocyte growth factor and vascular endothelial growth factor was significantly up-regulated in both HT3 and HT3+10, but not in HT10. In summary, intratracheal transplantation of human UCB derived MSCs time-dependently attenuated hyperoxia-induced lung injury in neonatal rats, showing significant protection only in the early but not in the late phase of inflammation. There were no synergies with combined early+late MSCs transplantation.
TL;DR: It is reported that human MSCs can expand CD14−CD11b+CD33+ human myeloid-derived suppressor cells (MDSCs) and the role of HGF, a mitogenic molecule, in the expansion of MDSCs is demonstrated.
Abstract: Mesenchymal stromal cells (MSCs) are multilineage progenitors with immunomodulatory properties, including expansion of immunomodulatory leukocytes such as regulatory T lymphocytes (Tregs) and tolerogenic dendritic cells. We report that human MSCs can expand CD14−CD11b+CD33+ human myeloid-derived suppressor cells (MDSCs). MSC-expanded MDSCs suppress allogeneic lymphocyte proliferation, express arginase-1 and inducible nitric oxide synthase, and increase the number of Tregs. This expansion occurs through the secretion of hepatocyte growth factor (HGF), with effects replicated by adding HGF singly and abrogated by HGF knockdown in MSCs. In wild-type mice, the liver, which secretes high levels of HGF, contains high numbers of Gr-1+CD11b+ MDSCs, and injection of HGF into mice significantly increases the number of MDSCs. Expansion of MDSCs by MSC-secreted HGF involves c-Met (its receptor) and downstream phosphorylation of STAT3, a key factor in MDSC expansion. Our data further support the strong immunomodulatory nature of MSCs and demonstrate the role of HGF, a mitogenic molecule, in the expansion of MDSCs.
TL;DR: It is suggested that human adipose tissue-derived mesenchymal stromal cells (hADSCs) transplanted into a rat model of SCI would be more appropriate for transplant to treat SCI than hBMSCs.
TL;DR: The results suggest that tubule-specific c-met signaling is crucial in conferring renal protection after AKI, primarily by its anti-apoptotic and anti-inflammatory mechanisms.
TL;DR: These data suggest that Wnt/β-catenin signaling is a key downstream effector of MET signaling and contributes to the maintenance of GSC and GBM malignancy.
Abstract: Background
Glioblastoma (GBM) is the most lethal and common type of primary brain tumor. Recent evidence suggests that a subpopulation of GBM cells (glioblastoma stem cells [GSCs]) is critical for tumor progression, invasion, and therapeutic resistance. We and others have demonstrated that MET, a receptor tyrosine kinase, positively regulates the stemness phenotype and radioresistance of GSCs. Here, we interrogated the downstream effector pathways of MET signaling in GSCs.
TL;DR: The findings imply that MSCs are able to ameliorate experimental peritoneal fibrosis by suppressing inflammation and TGF-β1 signaling in a paracrine manner.
TL;DR: It was concluded that SDF-1 genetic engineering is a promising way to promote the wound healing activity of MSC for a skin defect.
TL;DR: A robust culture system was developed that permitted expansion and genetic manipulation of cells capable of multilineage differentiation in vitro and in vivo to examine the individual roles of HGF/MET and EGF/EGFR in HPC self-renewal and binary cell fate decision and reveal a previously unrecognized link between EGFR and NOTCH1 in directing cholangiocyte differentiation.
Abstract: The relative contribution of hepatocyte growth factor (HGF)/MET and epidermal growth factor (EGF)/EGF receptor (EGFR), two key signal transduction systems in the normal and diseased liver, to fate decisions of adult hepatic progenitor cells (HPCs) has not been resolved. Here, we developed a robust culture system that permitted expansion and genetic manipulation of cells capable of multilineage differentiation in vitro and in vivo to examine the individual roles of HGF/MET and EGF/EGFR in HPC self-renewal and binary cell fate decision. By employing loss-of-function and rescue experiments in vitro, we showed that both receptors collaborate to increase the self-renewal of HPCs through activation of the extracellular signal-regulated kinase (ERK) pathway. MET was a strong inducer of hepatocyte differentiation by activating AKT and signal transducer and activator of transcription (STAT3). Conversely, EGFR selectively induced NOTCH1 to promote cholangiocyte specification and branching morphogenesis while concomitantly suppressing hepatocyte commitment. Furthermore, unlike the deleterious effects of MET deletion, the liver-specific conditional loss of Egfr facilitated rather than suppressed progenitor-mediated liver regeneration by switching progenitor cell differentiation toward hepatocyte lineage. These data provide new insight into the mechanisms regulating the stemness properties of adult HPCs and reveal a previously unrecognized link between EGFR and NOTCH1 in directing cholangiocyte differentiation.
TL;DR: It is suggested that M SC-CM enhanced periodontal regeneration due to multiple cytokines contained in MSC-CM because it displayed significantly greater alveolar bone and cementum regeneration than the other groups.
TL;DR: Ligand-independent activation of c- met contributes specifically to erlotinib resistance, not cetuximab resistance, in HNSCC with activated c-Src, where c-Met activation is more dependent on c- Src than on EGFR, providing an alternate survival pathway.
Abstract: Purpose: Strategies to inhibit the EGF receptor (EGFR) using the tyrosine kinase inhibitor erlotinib have been associated with limited clinical efficacy in head and neck squamous cell carcinoma (HNSCC). Co-activation of alternative kinases may contribute to erlotinib resistance. Experimental Design: We generated HNSCC cells expressing dominant-active c-Src (DA-Src) to determine the contribution of c-Src activation to erlotinib response. Results: Expression of DA-Src conferred resistance to erlotinib in vitro and in vivo compared with vector-transfected control cells. Phospho-Met was strongly upregulated by DA-Src, and DA-Src cells did not produce hepatocyte growth factor (HGF). Knockdown of c-Met enhanced sensitivity to erlotinib in DA-Src cells in vitro , as did combining a c-Met or c-Src inhibitor with erlotinib. Inhibiting EGFR resulted in minimal reduction of phospho-Met in DA-Src cells, whereas complete phospho-Met inhibition was achieved by inhibiting c-Src. A c-Met inhibitor significantly sensitized DA-Src tumors to erlotinib in vivo , resulting in reduced Ki67 labeling and increased apoptosis. In parental cells, knockdown of endogenous c-Src enhanced sensitivity to erlotinib, whereas treatment with HGF to directly induce phospho-Met resulted in erlotinib resistance. The level of endogenous phospho-c-Src in HNSCC cell lines was also significantly correlated with erlotinib resistance. Conclusions: Ligand-independent activation of c-Met contributes specifically to erlotinib resistance, not cetuximab resistance, in HNSCC with activated c-Src, where c-Met activation is more dependent on c-Src than on EGFR, providing an alternate survival pathway. Addition of a c-Met or c-Src inhibitor to erlotinib may increase efficacy of EGFR inhibition in patients with activated c-Src. Clin Cancer Res; 19(2); 380–92. ©2012 AACR .
TL;DR: CTCs show significantly increased tumorigenicity and metastatic potential in a novel orthotopic syngeneic model of metastatic HCC and it is concluded that during hematogenous dissemination in HCC, CTCs undergo EMT under the influence of increased HGF.
Abstract: Hepatocyte growth factor (HGF) and its receptor, c-Met, are important regulators of growth and differentiation of healthy hepatocytes. However, upregulation of HGF and c-Met have been associated with tumor progression and metastasis in hepatocellular carcinoma (HCC). Hematogenous dissemination is the most common route for cancer metastasis, but the role of HGF and c-Met in circulating tumor cells (CTCs) is unknown. We have isolated and established a circulating tumor cell line from the peripheral blood of a mouse HCC model. Our studies show that these CTCs have increased expression of HGF and c-Met in comparison to the primary tumor cells. The CTCs display phenotypic evidence of epithelial-mesenchymal transition (EMT) and the EMT appears to be inducible by HGF. Epigenetic analysis of the c-Met promoter identified significant loss of DNA methylation in CTCs which correlated with overexpression of c-Met and increased expression of HGF. Six specific CpG sites of c-Met promoter demethylation were identified. CTCs show significantly increased tumorigenicity and metastatic potential in a novel orthotopic syngeneic model of metastatic HCC. We conclude that during hematogenous dissemination in HCC, CTCs undergo EMT under the influence of increased HGF. This process also involves up regulation of c-Met via promoter demethylation at 6 CpG sites. Consequently, targeting HGF and c-Met expression by CTCs may be a novel non-invasive approach with potential clinical applications in HCC management.
TL;DR: Both tumor/epithelial and stromal characteristics play important roles in metabolism, including altered expression of HGF/Met pathway and GLUT1 expression in Warburg-like metabolism.
Abstract: Purpose: Cancer cells have altered metabolism, with increased glucose uptake, glycolysis, and biomass production. This study conducted genomic and metabolomic analyses to elucidate how tumor and stromal genomic characteristics influence tumor metabolism. Experimental Design: Thirty-three breast tumors and six normal breast tissues were analyzed by gene expression microarray and by mass spectrometry for metabolites. Gene expression data and clinical characteristics were evaluated in association with metabolic phenotype. To evaluate the role of stromal interactions in altered metabolism, cocultures were conducted using breast cancer cells and primary cancer-associated fibroblasts (CAF). Results: Across all metabolites, unsupervised clustering resulted in two main sample clusters. Normal breast tissue and a subset of tumors with less aggressive clinical characteristics had lower levels of nucleic and amino acids and glycolysis byproducts, whereas more aggressive tumors had higher levels of these Warburg-associated metabolites. While tumor-intrinsic subtype did not predict metabolic phenotype, metabolic cluster was significantly associated with expression of a wound response signature. In cocultures, CAFs from basal-like breast cancers increased glucose uptake and basal-like epithelial cells increased glucose oxidation and glycogen synthesis, suggesting interplay of stromal and epithelial phenotypes on metabolism. Cytokine arrays identified hepatocyte growth factor (HGF) as a potential mediator of stromal–epithelial interaction and antibody neutralization of HGF resulted in reduced expression of glucose transporter 1 ( GLUT1 ) and decreased glucose uptake by epithelium. Conclusions: Both tumor/epithelial and stromal characteristics play important roles in metabolism. Warburg-like metabolism is influenced by changes in stromal–epithelial interactions, including altered expression of HGF/Met pathway and GLUT1 expression. Clin Cancer Res; 19(3); 571–85. ©2012 AACR .
TL;DR: It is demonstrated that FACS-sorted malignant glioma-derived pericytes (HMGP) were characterized by the expression of CD90, CD248, and platelet-derived growth factor receptor-β (PDGFR-β), and suggested that these cells, besides their critical role in tumor vascularization, also promote local immunosuppression in malignantgliomas and possibly other brain diseases.
TL;DR: It is demonstrated that donor age significantly affects the ability of human ASCs to provide neuroprotection, immunomodulation, and/or remyelination in EAE mice, and age‐related therapeutic differences corroborate recent findings that biologic aging occurs in stem cells.
Abstract: There is a significant clinical need for effective therapies for primary progressive multiple sclerosis, which presents later in life (i.e., older than 50 years) and has symptoms that increase in severity without remission. With autologous mesenchymal stem cell therapy now in the early phases of clinical trials for all forms of multiple sclerosis (MS), it is necessary to determine whether autologous stem cells from older donors have therapeutic effectiveness. In this study, the therapeutic efficacy of human adipose-derived mesenchymal stem cells (ASCs) from older donors was directly compared with that of cells from younger donors for disease prevention. Mice were induced with chronic experimental autoimmune encephalomyelitis (EAE) using the myelin oligodendrocyte glycoprotein35-55 peptide and treated before disease onset with ASCs derived from younger ( 60 years) donors. ASCs from older donors failed to ameliorate the neurodegeneration associated with EAE, and mice treated with older donor cells had increased central nervous system inflammation, demyelination, and splenocyte proliferation in vitro compared with the mice receiving cells from younger donors. Therefore, the results of this study demonstrated that donor age significantly affects the ability of human ASCs to provide neuroprotection, immunomodulation, and/or remyelination in EAE mice. The age-related therapeutic differences corroborate recent findings that biologic aging occurs in stem cells, and the differences are supported by evidence in this study that older ASCs, compared with younger donor cells, secrete less hepatocyte growth factor and other bioactive molecules when stimulated in vitro. These results highlight the need for evaluation of autologous ASCs derived from older patients when used as therapy for MS.
TL;DR: HACE1 is identified as an antagonist of cell migration through its ability to degrade active Rac1 and rescues the migration defect of Rac1-null cells to a greater extent than wild-type Rac1.
Abstract: The small GTPase Rac1 is a key regulator of cell motility. Multiple mechanisms regulate Rac1 activity including its ubiquitylation and subsequent degradation. Here, we identify the tumour suppressor HACE1 (HECT domain and Ankyrin repeat Containing E3 ubiquitin-protein ligase 1) as an E3 ubiquitin ligase responsible for Rac1 degradation following activation by a migration stimulus. We show that HACE1 and Rac1 interaction is enhanced by hepatocyte growth factor (HGF) signalling, a Rac activator and potent stimulus of cell migration. Furthermore, HACE1 catalyses the poly-ubiquitylation of Rac1 at lysine 147 following its activation by HGF, resulting in its proteasomal degradation. This negative feedback mechanism likely restricts cell motility. Consistent with this, HACE1 depletion is accompanied by increased total Rac1 levels and accumulation of Rac1 in membrane ruffles. Moreover, HACE1-depletion enhances cell migration independently of growth factor stimulation, which may have significance for malignant conversion. A non-ubiquitylatable Rac1 rescues the migration defect of Rac1-null cells to a greater extent than wild-type Rac1. These findings identify HACE1 as an antagonist of cell migration through its ability to degrade active Rac1.
TL;DR: The results suggest that during aging, the dermal and epidermal skin compartments might be activated coordinately for initiation of skin carcinoma, via a paracrine axis in which MMPs secreted by senescent fibroblasts promote very early epithelial-mesenchymal transition of keratinocytes undergoing transformation and oversynthesizing the MMP-activatable receptor PAR-1.
Abstract: The incidence of carcinoma increases greatly with aging, but the cellular and molecular mechanisms underlying this correlation are only partly known. It is established that senescent fibroblasts promote the malignant progression of already-transformed cells through secretion of inflammatory mediators. We investigated here whether the senescent fibroblast secretome might have an impact on the very first stages of carcinogenesis. We chose the cultured normal primary human epidermal keratinocyte model, because after these cells reach the senescence plateau, cells with transformed and tumorigenic properties systematically and spontaneously emerge from the plateau. In the presence of medium conditioned by autologous senescent dermal fibroblasts, a higher frequency of post-senescence emergence was observed and the post-senescence emergent cells showed enhanced migratory properties and a more marked epithelial-mesenchymal transition. Using pharmacological inhibitors, siRNAs, and blocking antibodies, we demonstrated that the MMP-1 and MMP-2 matrix metalloproteinases, known to participate in late stages of cancer invasion and metastasis, are responsible for this enhancement of early migratory capacity. We present evidence that MMPs act by activating the protease-activated receptor 1 (PAR-1), whose expression is specifically increased in post-senescence emergent keratinocytes. The physiopathological relevance of these results was tested by analyzing MMP activity and PAR-1 expression in skin sections. Both were higher in skin sections from aged subjects than in ones from young subjects. Altogether, our results suggest that during aging, the dermal and epidermal skin compartments might be activated coordinately for initiation of skin carcinoma, via a paracrine axis in which MMPs secreted by senescent fibroblasts promote very early epithelial-mesenchymal transition of keratinocytes undergoing transformation and oversynthesizing the MMP-activatable receptor PAR-1.
TL;DR: WJ-MSCs contribute to tubular EMT delay and the alleviation of renal fibrosis, and induction of native and foreign HGF synthesis in damaged TECs at the initial stage of AKI leads to recovery of the disturbed balance of HGF/TGF-β1 during scar formation.
Abstract: Based on some well-documented reports, we attempted to clarify the antifibrotic mechanisms of human Wharton’s-jelly-derived mesenchymal stromal cells (WJ-MSCs) from the perspective of induction of hepatocyte growth factor (HGF) expression in tubular epithelial cells (TECs). A rat model of acute kidney injury (AKI) was established through unilateral renal ischemia for 1 hour. Two days later, a single intravenous cell or vehicle injection, or contralateral nephrectomy, was performed. Rats were sacrificed at 1 day, 1 week, 4 weeks, or 6 weeks after the intervention. Renal fibrosis was evaluated by Masson trichrome staining and Sircol collagen assay. The upregulation of α-smooth muscle actin (α-SMA) versus E-cadherin expression was adopted as an indicator of tubular epithelial-mesenchymal transition (EMT). Gene and protein expression of HGF or transforming growth factor-beta1 (TGF-β1) was determined by real-time polymerase chain reaction (RT-PCR) and Western blot, respectively. HGF expression in TECs was detected with immunostaining. In vitro, rat TECs subjected to hypoxia injury were incubated with or without conditioned medium (CM) from WJ-MSCs for 1, 3, 24, or 48 hours. Rat or human HGF synthesis in TECs was assessed with immunostaining, RT-PCR, or ELISA. Cell delivery or nephrectomy led to abrogation of renal scarring. At the incipient period of AKI, through induction of HGF expression, either of them remarkably promoted the upregulation of HGF versus TGF-β1 expression in damaged kidney. Rat TECs were not only the principal cells expressing HGF but also exhibited human HGF expression after cell infusion. During fibrogenesis, the downregulation of HGF versus TGF-β1 expression was greatly prevented by WJ-MSCs or kidney removal, thereby resulting in tubular EMT delay. In vitro, after 24 or 48 hours of incubation, CM not only robustly induced the upregulation of rat HGF gene expression in TECs but substantially amplified the release of rat HGF. Under the induction of CM, human HGF mRNA and protein were detected in rat TECs. WJ-MSCs contribute to tubular EMT delay and the alleviation of renal fibrosis. Induction of native and foreign HGF synthesis in damaged TECs at the initial stage of AKI leads to recovery of the disturbed balance of HGF/TGF-β1 during scar formation, being one of the vital mechanisms.
TL;DR: The results demonstrate that VEGF expression was reduced in homografts of CT26-NK4 cells, compared to those of the control cells, and suggest that HGF/c‑Met signalling may be a promising target for anti-angiogenic strategies.
Abstract: In the present study, we assessed the involvement of hepatocyte growth factor (HGF)/c-Met signalling with vascular endothelial cell growth factor (VEGF) and hypoxia inducible factor (HIF)-1α expression in the downstream pathways phosphatidylinositol 3-kinase (PI3K)/Akt, mitogen-activated protein kinase (MAPK) and signal transducer and activator of transcription 3 (STAT3) in CT26 cells, to determine the mechanisms of the potent anti-angiogenic effect of NK4. We established genetically modified CT26 cells to produce NK4 (CT26-NK4). VEGF expression in subcutaneous CT26 tumours in vivo and in culture supernatants in vitro was determined by ELISA. HIF-1α expression in nuclear extracts was evaluated by western blot analysis. VEGF and HIF-1α mRNA levels were examined by real-time reverse transcription-polymerase chain reaction (RT-PCR). The DNA binding activity of HIF-1α was evaluated using an HIF-1α transcription factor assay kit. Our results demonstrated that VEGF expression was reduced in homografts of CT26-NK4 cells, compared to those of the control cells. In vitro, VEGF expression, which was induced by HGF, was inhibited by anti-HGF antibody, NK4 and by kinase inhibitors (PI3K, LY294002; MAPK, PD98059; and STAT3, Stattic). HGF‑induced HIF‑1α transcriptional activity was also inhibited by the kinase inhibitors. Real-time RT-PCR demonstrated that HGF‑induced HIF‑1α mRNA expression was not inhibited by LY294002 and PD98059, but was inhibited by Stattic. These data suggest that the PI3K/Akt, MAPK and STAT3 pathways, downstream of HGF/c‑Met signalling, are involved in the regulation of VEGF expression in CT26 cells. HGF/c‑Met signalling may be a promising target for anti-angiogenic strategies.