Effect of antibody-mediated connective tissue growth factor neutralization on lung edema in ventilator-induced lung injury in rats.

BACKGROUND: Acute respiratory distress syndrome (ARDS) is characterized by alveolar edema that can progress to septal fibrosis. Mechanical ventilation can augment lung injury, termed ventilator-induced lung injury (VILI). Connective tissue growth factor (CTGF), a mediator of fibrosis, is increased in ARDS patients. Blocking CTGF inhibits fibrosis and possibly vascular leakage. This study investigated whether neutralizing CTGF reduces pulmonary edema in VILI. METHODS: Following LPS administration, rats were mechanically ventilated for 6 h with low (6 mL/kg; low VT) or moderate (10 mL/kg; mod VT) tidal volume and treated with a neutralizing CTGF antibody (FG-3154) or placebo lgG (vehicle). Control rats without LPS were ventilated for 6 h with low VT. Lung wet-to-dry weight ratio, FITC-labeled dextran permeability, histopathology, and soluble RAGE were determined. RESULTS: VILI was characterized by reduced PaO2/FiO2 ratio (low VT: 540 [381-661] vs. control: 693 [620-754], p < 0.05), increased wet-to-dry weight ratio (low VT: 4.8 [4.6-4.9] vs. control: 4.5 [4.4-4.6], p < 0.05), pneumonia (low VT: 30 [0-58] vs. control: 0 [0-0]%, p < 0.05) and interstitial inflammation (low VT: 2 [1-3] vs. control: 1 [0-1], p < 0.05). FG-3154 did not affect wet-to-dry weight ratio (mod VT + FG-3154: 4.8 [4.7-5.0] vs. mod VT + vehicle: 4.8 [4.8-5.0], p > 0.99), extravasated dextrans (mod VT + FG-3154: 0.06 [0.04-0.09] vs. mod VT + vehicle: 0.04 [0.03-0.09] µg/mg tissue, p > 0.99), sRAGE (mod VT + FG-3154: 1865 [1628-2252] vs. mod VT + vehicle: 1885 [1695-2159] pg/mL, p > 0.99) or histopathology. CONCLUSIONS: 'Double hit' VILI was characterized by inflammation, impaired oxygenation, pulmonary edema and histopathological lung injury. Blocking CTGF does not improve oxygenation nor reduce pulmonary edema in rats with VILI.

Liquiritigenin Blocks Breast Cancer Progression by Inhibiting Connective Tissue Growth Factor Expression via Up-Regulating miR-383-5p.

The objective of this study was to investigate the effect of liquiritigenin (LQ) on breast cancer (BC) and its mechanism. After BC cell lines and normal mammary epithelial cells were cultured with LQ, CCK-8, and Scratch, Transwell assays and flow cytometry were applied to test the effect of LQ on cell proliferation, migration, invasion, and apoptosis. The effect of LQ on the expression of microRNA-383-5p (miR-383-5p) and connective tissue growth factor (CTGF) was measured by qRT-PCR and Western blotting. Bioinformatics prediction was used to evaluate the binding relationship between miR-383-5p and CTGF, which was verified by dual-luciferase reporter assay. After miR-383-5p and/or CTGF expression was upregulated through cell transfection, the relationship between miR-383-5p and CTGF, as well as their effects on BC, was further assessed. The results showed that LQ can significantly inhibit CTGF expression and the proliferative, migratory, and invasive abilities of BC cells, while facilitating apoptosis of BC cells and miR-383-5p expression. The inhibiting effect of LQ was dose-dependently enhanced in BC cells. Dual-luciferase reporter assay verified that miR-383-5p targeted CTGF. CTGF expression was inversely regulated by miR-383-5p. CTGF upregulation repressed the suppressive effect of miR-385-5p on BC cell development. In conclusion, LQ can inhibit CTGF expression by upregulating miR-383-5p, thereby inhibiting proliferative, migratory, and invasive abilities and promoting apoptosis of BC cells.

Dysregulation of PI3K and Hippo signaling pathways synergistically induces chronic pancreatitis via CTGF upregulation.

The role of PI3K and Hippo signaling in chronic pancreatitis (CP) pathogenesis is unclear. Therefore, we assessed the involvement of these pathways in CP by examining the PI3K and Hippo signaling components PTEN and SAV1, respectively. We observed significant decreases in pancreatic PTEN and SAV1 levels in 2 murine CP models: repeated cerulein injection and pancreatic ductal ligation. Additionally, pancreas-specific deletion of Pten and Sav1 (DKO) induced CP in mice. Pancreatic connective tissue growth factor (CTGF) was markedly upregulated in both CP models and DKO mice, and pancreatic CCAAT/enhancer-binding protein-α (CEBPA) expression was downregulated in the CP models. Interestingly, in pancreatic acinar cells (PACs), CEBPA knockdown reduced PTEN and SAV1 and increased CTGF levels in vitro. Furthermore, CEBPA knockdown in PACs induced acinar-to-ductal metaplasia and activation of cocultured macrophages and pancreatic stellate cells. These results were mitigated by CTGF inhibition. CP in DKO mice was also ameliorated by Ctgf gene deletion, and cerulein-induced CP was alleviated by antibody-mediated CTGF neutralization. Finally, we observed significantly decreased PTEN, SAV1, and CEBPA and increased CTGF levels in human CP tissues compared with nonpancreatitis tissues. Taken together, our results indicate that dysregulation of PI3K and Hippo signaling induces CP via CTGF upregulation.

Targeting CTGF in Cancer: An Emerging Therapeutic Opportunity.

Despite the dramatic advances in cancer research over the decades, effective therapeutic strategies are still urgently needed. Increasing evidence indicates that connective tissue growth factor (CTGF), a multifunctional signaling modulator, promotes cancer initiation, progression, and metastasis by regulating cell proliferation, migration, invasion, drug resistance, and epithelial-mesenchymal transition (EMT). CTGF is also involved in the tumor microenvironment in most of the nodes, including angiogenesis, inflammation, and cancer-associated fibroblast (CAF) activation. In this review, we comprehensively discuss the expression of CTGF and its regulation, oncogenic role, clinical relevance, targeting strategies, and therapeutic agents. Herein, we propose that CTGF is a promising cancer therapeutic target that could potentially improve the clinical outcomes of cancer patients.

Blocking CTGF/CCN2 reverses neural fibrosis and sensorimotor declines in a rat model of overuse-induced median mononeuropathy.

Encapsulation of median nerves is a hallmark of overuse-induced median mononeuropathy and contributes to functional declines. We tested if an antibody against CTGF/CCN2 (termed FG-3019 or Pamrevlumab) reduces established neural fibrosis and sensorimotor declines in a clinically relevant rodent model of overuse in which median mononeuropathy develops. Young adult female rats performed a high repetition high force (HRHF) lever-pulling task for 18 weeks. Rats were then euthanised at 18 weeks (HRHF untreated), or rested and systemically treated for 6 weeks with either an anti-CCN2 monoclonal antibody (HRHF-Rest/FG-3019) or IgG (HRHF-Rest/IgG), with results compared with nontask control rats. Neuropathology was evident in HRHF-untreated and HRHF-Rest/IgG rats as increased perineural collagen deposition and degraded myelin basic protein (dMBP) in median nerves, and increased substance P in lower cervical dorsal root ganglia (DRG), compared with controls. Both groups showed functional declines, specifically, decreased sensory conduction velocity in median nerves, noxious cold temperature hypersensitivity, and grip strength declines, compared with controls. There were also increases of ATF3-immunopositive nuclei in ventral horn neurons in HRHF-untreated rats, compared with controls (which showed none). FG-3019-treated rats showed no increase above control levels of perineural collagen or dMBP in median nerves, Substance P in lower cervical DRGs, or ATF3-immunopositive nuclei in ventral horns, and similar median nerve conduction velocities and thermal sensitivity, compared with controls. We hypothesize that neural fibrotic processes underpin the sensorimotor declines by compressing or impeding median nerves during movement, and that inhibiting fibrosis using an anti-CCN2 treatment reverses these effects.

Roles of Interaction between CCN2 and Rab14 in Aggrecan Production by Chondrocytes.

To identify proteins that cooperate with cellular communication network factor 2 (CCN2), we carried out GAL4-based yeast two-hybrid screening using a cDNA library derived from the chondrocytic cell line HCS-2/8. Rab14 GTPase (Rab14) polypeptide was selected as a CCN2-interactive protein. The interaction between CCN2 and Rab14 in HCS-2/8 cells was confirmed using the in situ proximity ligation assay. We also found that CCN2 interacted with Rab14 through its IGFBP-like domain among the four domains in CCN2 protein. To detect the colocalization between CCN2 and Rab14 in the cells in detail, CCN2, wild-type Rab14 (Rab14WT), a constitutive active form (Rab14CA), and a dominant negative form (Rab14DN) of Rab14 were overexpressed in monkey kidney-tissue derived COS7 cells. Ectopically overexpressed Rab14 showed a diffuse cytosolic distribution in COS7 cells; however, when Rab14WT was overexpressed with CCN2, the Rab14WT distribution changed to dots that were evenly distributed within the cytosol, and both Rab14 and CCN2 showed clear colocalization. When Rab14CA was overexpressed with CCN2, Rab14CA and CCN2 also showed good localization as dots, but their distribution was more widespread within cytosol. The coexpression of Rab14DN and CCN2 also showed a dotted codistribution but was more concentrated in the perinuclear area. Quantitative reverse transcription polymerase chain reaction (qRT-PCR) analysis revealed that the reduction in RAB14 or CCN2 mRNA by their respective siRNA significantly enhanced the expression of ER stress markers, BIP and CHOP mRNA in HCS-2/8 chondrocytic cells, suggesting that ER and Golgi stress were induced by the inhibition of membrane vesicle transfer via the suppression of CCN2 or Rab14. Moreover, to study the effect of the interaction between CCN2 and its interactive protein Rab14 on proteoglycan synthesis, we overexpressed Rab14WT or Rab14CA or Rab14DN in HCS-2/8 cells and found that the overexpression of Rab14DN decreased the extracellular proteoglycan accumulation more than the overexpression of Rab14WT/CA did in the chondrocytic cells. These results suggest that intracellular CCN2 is associated with Rab14 on proteoglycan-containing vesicles during their transport from the Golgi apparatus to endosomes in chondrocytes and that this association may play a role in proteoglycan secretion by chondrocytes.

Effects of intravitreal connective tissue growth factor neutralizing antibody on choroidal neovascular membrane-associated subretinal fibrosis.

Connective tissue growth factor (CTGF) plays an essential role in the regulation of extracellular matrix proteins and pro-fibrotic and angiogenic factors. This experimental research was conducted to evaluate if CTGF is elevated after induction of a choroidal neovascular membrane (CNVM) and whether intravitreal anti-CTGF without and with intravitreal bevacizumab (IVB) may have any effect on the CNVM associated sub-retinal fibrosis. In adherence to ARRIVE guidelines, CNVM was induced by laser spots in the right eye retinas of ninety-four pigmented rats. Quantitative real-time reverse transcription PCR (qRT-PCR) and western-blot analysis were performed on sclerochoroidal tissues of forty-four rats before and at different time intervals after laser application. The remaining fifty rats were randomly divided into five groups after laser application. Group A received intravitreal injection of 2  µl of the 50 µg/ml anti-CTGF. In group B, intravitreal injection of 2  µl of 25 mg/ml bevacizumab was performed. Group C received 1  µl intravitreal anti-CTGF and 1  µl IVB. Group D did not receive any intravitreal injection as the control group. In group E, intravitreal injection of 2  µl of nonspecific purified mouse IgG antibody was performed as the placebo group. After two weeks, double immunohistochemistry was performed by isolectin B4 and anti-collagen type1 on the sclerochoroidal flat-mounts. Masked measurement of the fluorescent images of the CNVM and CNVM associated sub-retinal fibrosis areas was performed using the image J software. Ctgf mRNA and CTGF protein levels increased to the maximum level in 24 h after laser application and remained higher than the control level up to the 14th day for the Ctgf mRNA and up to the 7th day for the CTGF protein level. Means of CNVM associated sub-retinal fibrosis areas in three treatment groups (A, B and C) were significantly less than the control (D) and placebo (E) groups (P < 0.001, <0.05, <0.001 respectively). For groups A and C, mean CNVM associated sub-retinal fibrosis areas were also significantly less than group B (P < 0.05 and < 0.01, respectively). In conclusion, this study showed significant reduction of the CNVM associated sub-retinal fibrosis via inhibition of the CTGF which mediates the final steps of fibrosis in various inflammatory and angiogenic pathways.

Connective tissue growth factor mediates transforming growth factor ß-induced collagen expression in human endometrial stromal cells.

BACKGROUND: Adenomyosis is a medical condition defined by the abnormal presence of endometrial tissue within the myometrium, in which fibrosis occurs with new collagen deposition and myofibroblast differentiation. In this study, the effect of several mediators and growth factors on collagen expression was investigated on human endometrial stromal cells (fibroblasts) derived from adenomyotic endometrium. EXPERIMENTAL APPROACH: RT-PCR, Western blot analysis, pharmacological interventions and siRNA interference were applied to primary cultured human endometrial stromal cells (fibroblasts). Immunohistochemistry was used to analyze protein expression in adenomyotic endometrium tissue specimens. RESULTS: Of the tested mediators, transforming growth factor ß1 (TGFß1) and its isoforms were effective to induce collagen and connective tissue growth factor (CTGF) expression. Collagen and CTGF induction by TGFß1 could be reduced by the inhibitors targeting DNA transcription, protein translation, and Smad2/3 signaling. Interestingly, TGFß1 induced Smad2/3 phosphorylation and CTGF mRNA expression, but not collagen mRNA expression, suggesting that TGFß1 mediates collagen expression through CTGF induction and Smad2/3 activation. In parallel, TGFß1 and CTGF also induced expression of heat shock protein (HSP) 47, a protein required for the synthesis of several types of collagens. However, only CTGF siRNA knockdown, could compromise TGFß1-induced collagen expression. Finally, the immunohistochemistry revealed vimentin- and α-SMA-positive staining for (myo)fibroblasts, TGFß1, collagen, and CTGF in the subepithelial stroma region of human adenomyotic endometria. CONCLUSION AND IMPLICATIONS: We reveal here that TGFß1, collagen, and CTGF are expressed in the stroma of adenomyotic endometria and demonstrate that TGFß1 can induce collagen production in endometrium-derived fibroblasts through cellular Smad2/3-dependent signaling pathway and CTGF expression, suggesting that endometrial TGFß may take part in the pathogenesis of adenomyosis and ectopic endometrium may participate in uterine adenomyosis.

Liraglutide improves myocardial fibrosis after myocardial infarction through inhibition of CTGF by activating cAMP in mice.

OBJECTIVE: To study the role and mechanism of liraglutide in myocardial fibrosis after myocardial infarction (MI). MATERIALS AND METHODS: A total of 72 C57/BL male mice were randomly divided into sham operation group (Sham group), myocardial infarction group (MI group), and liraglutide intervention group (Lira group). The left anterior descending coronary artery (LAD) of the mice in MI group and Lira group was ligated to establish the MI model. One week after the operation, the mice in Lira group were intraperitoneally injected with 100 µg/kg of liraglutide once a day for 4 weeks. The mice in Sham group and MI group were injected with the equal volume of normal saline. At the 5th week after the operation, the cardiac morphologic indexes and cardiac function indexes were measured by echocardiography. After an ultrasound, the heart specimens of the mice were immediately harvested by thoracotomy, and histomorphological hematoxylin-eosin (HE) staining, collagen fiber Masson staining, and immunohistochemical staining were performed. The infarction zone and the non-infarction zone were isolated from another heart specimen; the cyclic adenosine monophosphate (cAMP) and hydroxyproline content were determined; and the expression levels of transforming growth factor-ß1 (TGF-ß1) and connective tissue growth factor (CTGF) were detected by Reverse Transcription-Polymerase Chain Reaction (RT-PCR) and Western blotting. RESULTS: Liraglutide improved the cardiac function of mice after myocardial infarction. Liraglutide improved the myocardial fibrosis in mice after myocardial infarction. Liraglutide increased cAMP in myocardial cells of mice after myocardial infarction. Liraglutide did not change the TGF-ß1 expressions while reduced the CTGF expressions in infarct and non-infarct area of mice after myocardial infarction. CONCLUSIONS: Liraglutide, through increasing the level of cAMP, could decrease the deposition of collagen fibers in myocardial tissues of mice after MI, reduce the degree of infiltration of collagen fibers in the infarction zone into the myocardium in the non-infarction zone and inhibit the adverse ventricular remodeling in the non-infarction zone, thus improving the cardiac function after MI.

CTGF Mediates Tumor-Stroma Interactions between Hepatoma Cells and Hepatic Stellate Cells to Accelerate HCC Progression.

Connective tissue growth factor (CTGF) is a matricellular protein related to hepatic fibrosis. This study aims to clarify the roles of CTGF in hepatocellular carcinoma (HCC), which usually develops from fibrotic liver. CTGF was overexpressed in 93 human HCC compared with nontumorous tissues, primarily in tumor cells. Increased CTGF expression was associated with clinicopathologic malignancy of HCC. CTGF was upregulated in hepatoma cells in hepatocyte-specific Kras-mutated mice (Alb-Cre KrasLSL-G12D/+). Hepatocyte-specific knockout of CTGF in these mice (Alb-Cre KrasLSL-G12D/+ CTGFfl/fl) decreased liver tumor number and size. Hepatic stellate cells (HSC) were present in both human and murine liver tumors, and α-SMA expression, a marker of HSC activation, positively correlated with CTGF expression. Forced expression of CTGF did not affect growth of PLC/PRF/5 cells, a hepatoma cell line with little CTGF expression, but facilitated their growth in the presence of LX-2 cells, an HSC line. The growth of HepG2 cells, which express high levels of CTGF, was promoted by coculture with LX-2 cells compared with monoculture. Growth promotion by LX-2 cells was negated by an anti-CTGF antibody in both culture and xenografts. Coculturing LX-2 cells with HepG2 cells drove LX-2-derived production of IL6, which led to STAT-3 activation and proliferation of HepG2 cells. An anti-CTGF antibody reduced IL6 production in LX-2 cells and suppressed STAT-3 activation in HepG2 cells. In conclusion, our data identify tumor cell-derived CTGF as a keystone in the HCC microenvironment, activating nearby HSC that transmit progrowth signals to HCC cells, and this interaction is susceptible to inhibition by an anti-CTGF antibody.Significance: Protumor cross-talk between cancer cells and hepatic stellate cells presents an opportunity for therapeutic intervention against HCC.Graphical Abstract: http://cancerres.aacrjournals.org/content/canres/78/17/4902/F1.large.jpg Cancer Res; 78(17); 4902-14. ©2018 AACR.

Radiation-induced pulmonary gene expression changes are attenuated by the CTGF antibody Pamrevlumab.

BACKGROUND: Fibrosis is a delayed side effect of radiation therapy (RT). Connective tissue growth factor (CTGF) promotes the development of fibrosis in multiple settings, including pulmonary radiation injury. METHODS: To better understand the cellular interactions involved in RT-induced lung injury and the role of CTGF in these responses, microarray expression profiling was performed on lungs of irradiated and non-irradiated mice, including mice treated with the anti-CTGF antibody pamrevlumab (FG-3019). Between group comparisons (Welch's t-tests) and principal components analyses were performed in Genespring. RESULTS: At the mRNA level, the ability of pamrevlumab to prolong survival and ameliorate RT-induced radiologic, histologic and functional lung deficits was correlated with the reversal of a clear enrichment in mast cell, macrophage, dendritic cell and mesenchymal gene signatures. Cytokine, growth factor and matrix remodeling genes that are likely to contribute to RT pneumonitis and fibrosis were elevated by RT and attenuated by pamrevlumab, and likely contribute to the cross-talk between enriched cell-types in injured lung. CONCLUSIONS: CTGF inhibition had a normalizing effect on select cell-types, including immune cells not typically regarded as being regulated by CTGF. These results suggest that interactions between RT-recruited cell-types are critical to maintaining the injured state; that CTGF plays a key role in this process; and that pamrevlumab can ameliorate RT-induced lung injury in mice and may provide therapeutic benefit in other immune and fibrotic disorders.

Deletion of connective tissue growth factor ameliorates peritoneal fibrosis by inhibiting angiogenesis and inflammation.

Background: Connective tissue growth factor (CTGF/CCN2) regulates the signalling of other growth factors and promotes fibrosis. CTGF is increased in mice and humans with peritoneal fibrosis. Inhibition of CTGF has not been examined as a potential therapeutic target for peritoneal fibrosis because systemic CTGF knockout mice die at the perinatal stage. Methods: To study the role of CTGF in peritoneal fibrosis of adult mice, we generated CTGF conditional knockout (cKO) mice by crossing CTGF floxed mice with RosaCreERT2 mice. We administered tamoxifen to Rosa-CTGF cKO mice to delete the CTGF gene throughout the body. We induced peritoneal fibrosis by intraperitoneal injection of chlorhexidine gluconate (CG) in wild-type and Rosa-CTGF cKO mice. Results: Induction of peritoneal fibrosis in wild-type mice increased CTGF expression and produced severe thickening of the peritoneum. In contrast, CG-treated Rosa-CTGF cKO mice exhibited reduced thickening of the peritoneum. Peritoneal equilibration test revealed that the excessive peritoneal small-solute transport in CG-treated wild-type mice was normalized by CTGF deletion. CG-treated Rosa-CTGF cKO mice exhibited a reduced number of αSMA-, Ki67-, CD31- and MAC-2-positive cells in the peritoneum. Analyses of peritoneal mRNA showed that CG-treated Rosa-CTGF cKO mice exhibited reduced expression of Cd68, Acta2 (αSMA), Pecam1 (CD31) and Vegfa. Conclusions: These results indicate that a deficiency of CTGF can reduce peritoneal thickening and help to maintain peritoneal function by reducing angiogenesis and inflammation in peritoneal fibrosis. These results suggest that CTGF plays an important role in the progression of peritoneal fibrosis.

Verteporfin inhibits growth of human glioma in vitro without light activation.

Verteporfin (VP), a light-activated drug used in photodynamic therapy for the treatment of choroidal neovascular membranes, has also been shown to be an effective inhibitor of malignant cells. Recently, studies have demonstrated that, even without photo-activation, VP may still inhibit certain tumor cell lines, including ovarian cancer, hepatocarcinoma and retinoblastoma, through the inhibition of the YAP-TEAD complex. In this study, we examined the effects of VP without light activation on human glioma cell lines (LN229 and SNB19). Through western blot analysis, we identified that human glioma cells that were exposed to VP without light activation demonstrated a downregulation of YAP-TEAD-associated downstream signaling molecules, including c-myc, axl, CTGF, cyr61 and survivin and upregulation of the tumor growth inhibitor molecule p38 MAPK. In addition, we observed that expression of VEGFA and the pluripotent marker Oct-4 were also decreased. Verteporfin did not alter the Akt survival pathway or the mTor pathway but there was a modest increase in LC3-IIB, a marker of autophagosome biogenesis. This study suggests that verteporfin should be further explored as an adjuvant therapy for the treatment of glioblastoma.

Inhibition of CTGF ameliorates peritoneal fibrosis through suppression of fibroblast and myofibroblast accumulation and angiogenesis.

Peritoneal fibrosis (PF) is a serious complication in various clinical settings, but the mechanisms driving it remain to be fully determined. Connective tissue growth factor (CTGF) is known to regulate fibroblast activities. We therefore examined if CTGF inhibition has anti-fibrotic effects in PF. PF was induced by repetitive intraperitoneal injections of chlorhexidine gluconate (CG) in mice with type I pro-collagen promoter-driven green fluorescent protein (GFP) expression to identify fibroblasts. FG-3019, an anti-CTGF monoclonal antibody, was used to inhibit CTGF. CG-induced PF was significantly attenuated in FG-3019-treated mice. CG challenges induced marked accumulations of proliferating fibroblasts and of myofibroblasts, which were both reduced by FG-3019. Levels of peritoneal CTGF expression were increased by CG challenges, and suppressed in FG-3019-treated mice. FG-3019 treatment also reduced the number of CD31+ vessels and VEGF-A-positive cells in fibrotic peritoneum. In vitro studies using NIH 3T3 fibroblasts and peritoneal mesothelial cells (PMCs) showed that CTGF blockade suppressed TGF-ß1-induced fibroblast proliferation and myofibroblast differentiation, PMC mesothelial-to-mesenchymal transition, and VEGF-A production. These findings suggest that the inhibition of CTGF by FG-3019 might be a novel treatment for PF through the regulation of fibroblast and myofibroblast accumulation and angiogenesis.

The pancreatic cancer microenvironment: A true double agent.

The tumor microenvironment in pancreatic cancer is a complex balance of pro- and anti-tumor components. The dense desmoplasia consists of immune cells, extracellular matrix, growth factors, cytokines, and cancer associated fibroblasts (CAF) or pancreatic stellate cells (PSC). There are a multitude of targets including hyaluronan, angiogenesis, focal adhesion kinase (FAK), connective tissue growth factor (CTGF), CD40, chemokine (C-X-C motif) receptor 4 (CXCR-4), immunotherapy, and Vitamin D. The developing clinical therapeutics will be reviewed.

Effects of CTGF Blockade on Attenuation and Reversal of Radiation-Induced Pulmonary Fibrosis.

Background: Radiotherapy is a mainstay for the treatment of lung cancer that can induce pneumonitis or pulmonary fibrosis. The matricellular protein connective tissue growth factor (CTGF) is a central mediator of tissue remodeling. Methods: A radiation-induced mouse model of pulmonary fibrosis was used to determine if transient administration of a human antibody to CTGF (FG-3019) started at different times before or after 20 Gy thoracic irradiation reduced acute and chronic radiation toxicity. Mice (25 mice/group; 10 mice/group in a confirmation study) were examined by computed tomography, histology, gene expression changes, and for survival. In vitro experiments were performed to directly study the interaction of CTGF blockade and radiation. All statistical tests were two-sided. Results: Administration of FG-3019 prevented (∼50%-80%) or reversed (∼50%) lung remodeling, improved lung function, improved mouse health, and rescued mice from lethal irradiation ( P < .01). Importantly, when antibody treatment was initiated at 16 weeks after thoracic irradiation, FG-3019 reversed established lung remodeling and restored lung function. CTGF blockade abrogated M2 polarized macrophage influx, normalized radiation-induced gene expression changes, and reduced myofibroblast abundance and Osteopontin expression. Conclusion: These results indicate that blocking CTGF attenuates radiation-induced pulmonary remodeling and can reverse the process after initiation. CTGF has a central role in radiation-induced fibrogenesis, and FG-3019 may benefit patients with radiation-induced pulmonary fibrosis or patients with other forms or origin of chronic fibrotic diseases.

Treatment of Renal Fibrosis-Turning Challenges into Opportunities.

Current treatment modalities are not effective in halting the progression of most CKD. Renal fibrosis is a pathological process common to all CKD and thereby represents an excellent treatment target. A large number of molecular pathways involved in renal fibrosis were identified in preclinical studies, some of them being similar among different organs and some with available drugs in various phases of clinical testing. Yet only few clinical trials with antifibrotic drugs are being conducted in CKD patients. Here we review those clinical trials, focusing on agents with direct antifibrotic effects, with particular focus on pirfenidone and neutralizing antibodies directed against profibrotic growth factors and cell connection proteins. We discuss the potential reasons for the poor translation in treatment of renal fibrosis and propose possible approaches and future developments to improve it, eg, patient selection and companion diagnostics, specific and sensitive biomarkers as novel end points for clinical trials, and drug-targeting and theranostics.

Bone marrow derived mesenchymal stem cells inhibit the proliferative and profibrotic phenotype of hypertrophic scar fibroblasts and keloid fibroblasts through paracrine signaling.

BACKGROUND: Hypertrophic scars and keloids, characterized by over-proliferation of fibroblasts and aberrant formation of the extracellular matrix (ECM), are considered fibrotic diseases. Accumulating evidence indicates that mesenchymal stem cells (MSCs) promote scar-free wound healing and inhibit fibrotic tissue formation, making them a potentially effective therapeutic treatment for hypertrophic scars and keloids. OBJECTIVE: To investigate the paracrine effects of bone marrow derived MSCs (BMSCs) on the biological behavior of hypertrophic scar fibroblasts (HSFs) and keloid fibroblasts (KFs). METHODS: Proliferative and profibrotic phenotype changes of the fibroblasts were analyzed by immunofluorescence staining, in-cell western blot, and real-time PCR. RESULTS: BMSC-conditioned medium inhibited HSF and KF proliferation and migration, but did not induce apoptosis. Interestingly, normal skin fibroblast-conditioned medium exhibited no inhibitory effects on HSF or KF proliferation and migration. Furthermore, BMSC-conditioned medium significantly decreased expression of profibrotic genes, including connective tissue growth factor, plasminogen activator inhibitor-1, transforming growth factor-ß1, and transforming growth factor-ß2, in HSFs and KFs at both transcriptional and translational levels. In contrast, the expression of antifibrotic genes, such as transforming growth factor-ß3 and decorin, was substantially enhanced under the same culture conditions. Finally, we observed that BMSC-conditioned medium suppressed the ECM synthesis in HSFs and KFs, as indicated by decreased expression of collagen I and fibronectin and low levels of hydroxyproline in cell culture supernatant. CONCLUSION: These findings suggest that BMSCs attenuate the proliferative and profibrotic phenotype associated with HSFs and KFs and inhibit ECM synthesis through a paracrine signaling mechanism.

Microrna-199a-5p Functions as a Tumor Suppressor via Suppressing Connective Tissue Growth Factor (CTGF) in Follicular Thyroid Carcinoma.

BACKGROUND The objective of this study was to explore the role of miR-199a-5p in the development of thyroid cancer, including its anti-proliferation effect and downstream signaling pathway. MATERIAL AND METHODS We conducted qRT-PCR analysis to detect the expressions of several microRNAs in 42 follicular thyroid carcinoma patients and 42 controls. We identified CTGF as target of miR-491, and viability and cell cycle status were determined in FTC-133 cells transfected with CTGF siRNA, miR-199a mimics, or inhibitors. RESULTS We identified an underexpression of miR-199a-5p in follicular thyroid carcinoma tissue samples compared with controls. Then we confirmed CTGF as a target of miR-199a-5p thyroid cells by using informatics analysis and luciferase reporter assay. Additionally, we found that mRNA and protein expression levels of CTGF were both clearly higher in malignant tissues than in benign tissues. miR-199a-5p mimics and CTGF siRNA similarly downregulated the expression of CTGF, and reduced the viability of FTC-133 cells by arresting the cell cycle in G0 phase. Transfection of miR-199a-5p inhibitors increased the expression of CTGF and promoted the viability of the cells by increasing the fraction of cells in G2/M and S phases. CONCLUSIONS Our study proves that the CTGF gene is a target of miR-199a-5p, demonstrating the negatively related association between CTGF and miR-199a. These findings suggest that miR-199a-5p might be a novel therapeutic target in the treatment of follicular thyroid carcinoma.

FG-3019 anti-connective tissue growth factor monoclonal antibody: results of an open-label clinical trial in idiopathic pulmonary fibrosis.

FG-3019 is a fully human monoclonal antibody that interferes with the action of connective tissue growth factor, a central mediator in the pathogenesis of fibrosis.This open-label phase 2 trial evaluated the safety and efficacy of two doses of FG-3019 administered by intravenous infusion every 3 weeks for 45 weeks in patients with idiopathic pulmonary fibrosis (IPF). Subjects had a diagnosis of IPF within the prior 5 years defined by either usual interstitial pneumonia (UIP) pattern on a recent high-resolution computed tomography (HRCT) scan, or a possible UIP pattern on HRCT scan and a recent surgical lung biopsy showing UIP pattern. Pulmonary function tests were performed every 12 weeks, and changes in the extent of pulmonary fibrosis were measured by quantitative HRCT scans performed at baseline and every 24 weeks.FG-3019 was safe and well-tolerated in IPF patients participating in the study. Changes in fibrosis were correlated with changes in pulmonary function.Further investigation of FG-3019 in IPF with a placebo-controlled clinical trial is warranted and is underway.