TGF-β and NF-κB signal pathway cross-talk is mediated through TAK1 and SMAD7 in a subset of head and neck cancers

Loss of CYLD promotes cell invasion via ALK5 stabilization in oral squamous cell carcinoma

Oral squamous cell carcinoma (OSCC) has a very poor prognosis because of its highly invasive nature, and the 5-year survival rate has not changed appreciably for the past 30 years. Although cylindromatosis (CYLD), a deubiquitinating enzyme, is thought to be a potent tumour suppressor, its biological and clinical significance in OSCC is largely unknown. This study aimed to clarify the roles of CYLD in OSCC progression. Our immunohistochemical analyses revealed significantly reduced CYLD expression in invasive areas in OSCC tissues, whereas CYLD expression was conserved in normal epithelium and carcinoma in situ. Furthermore, downregulation of CYLD by siRNA led to the acquisition of mesenchymal features and increased migratory and invasive properties in OSCC cells and HaCaT keratinocytes. It is interesting that CYLD knockdown promoted transforming growth factor-β (TGF-β) signalling by inducing stabilization of TGF-β receptor I (ALK5) in a cell autonomous fashion. In addition, the response to exogenous TGF-β stimulation was enhanced by CYLD downregulation. The invasive phenotypes induced by CYLD knockdown were completely blocked by an ALK5 inhibitor. In addition, lower expression of CYLD was significantly associated with the clinical features of deep invasion and poor overall survival, and also with increased phosphorylation of Smad3, which is an indicator of activation of TGF-β signalling in invasive OSCC. These findings suggest that downregulation of CYLD promotes invasion with mesenchymal transition via ALK5 stabilization in OSCC cells. Copyright © 2017 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Mesenchymal stem cell deficiency influences megakaryocytopoiesis through the TNFAIP3/NF-κB/SMAD pathway in patients with immune thrombocytopenia

Immune thrombocytopenia (ITP) is an autoimmune disease. Mesenchymal stem cells (MSCs) play important roles in the physiology and homeostasis of the haematopoietic system, including supporting megakaryocytic differentiation from CD34⁺ haematopoietic progenitor cells. Tumour necrosis factor alpha-induced protein 3 (TNFAIP3, also termed A20) plays a key role in terminating NF-κB signalling. Human genetic studies showed that the polymorphisms of the TNFAIP3 gene may contribute to ITP susceptibility. In this study, we showed a significant decrease in TNFAIP3 and increase in NF-κB/SMAD7 in ITP-MSCs. In co-cultures with CD34⁺ cells, NF-κB was overexpressed in MSCs from healthy controls (HC-MSCs) after transfection with NFKBIA (IκB)-specific short hairpin (sh)RNAs, resulting in MSC deficiency and a reduction in megakaryocytic differentiation and thrombopoiesis. Knockdown of TNFAIP3 expression using TNFAIP3-specific shRNAs in HC-MSCs affected megakaryocytopoiesis. However, IKBKB knockdown corrected megakaryocytopoiesis inhibition in the ITP-MSCs by decreasing NF-κB expression. Amplified TNFAIP3 expression in ITP-MSCs by TNFAIP3 cDNA can facilitate megakaryocyte differentiation. shRNA-mediated knockdown of SMAD7 expression rescued the impaired MSC function in ITP patients. Therefore, we demonstrate that a pathological reduction in TNFAIP3 levels induced NF-κB/SMAD7 pathway activation, causing a deficiency in MSCs in ITP patients. The ability of ITP-MSCs to support megakaryocytic differentiation and thrombopoiesis of CD34⁺ cells was impaired.

Salidroside ameliorates autophagy and activation of hepatic stellate cells in mice via NF-κB and TGF-β1/Smad3 pathways

PURPOSE

Liver fibrosis is commonly seen and a necessary stage in chronic liver disease. The aim of this study was to explore the effect of salidroside on liver fibrosis in mice and its potential mechanisms.

MATERIALS AND METHODS

Two mouse liver fibrosis models were established by intraperitoneal injection of carbon tetrachloride (CCl₄) for 8 weeks and bile duct ligation for 14 days. Salidroside was injected intraperitoneally at doses of 10 and 20 mg/kg once a day. Gene and protein expression levels were determined by quantitative real-time polymerase chain reaction, enzyme-linked immunosorbent assay, Western blot, immunohistochemistry, and immunofluorescence.

RESULTS

Salidroside inhibited the production of extracellular matrix (ECM) and regulated the balance between MMP2 and TIMP1 and, therefore, alleviated liver fibrosis in the two fibrosis models. Salidroside reduced the production of transforming growth factor (TGF)-β1 in Kupffer cells and hepatic stellate cells (HSCs) via the nuclear factor-κB signaling pathway and, therefore, inhibited the activation of HSCs and autophagy by downregulation of the TGF-β1/Smad3 signaling pathway.

CONCLUSION

Salidroside can effectively attenuate liver fibrosis by inhibiting the activation of HSCs in mice.

Sustained anti-inflammatory effects of TGF-β1 on microglia/macrophages

Ischemic brain injuries caused release of damage-associated molecular patterns (DAMPs) that activate microglia/macrophages (MG/MPs) by binding to Toll-like receptors. Using middle cerebral artery transiently occluded rats, we confirmed that MG/MPs expressed inducible nitric oxide synthase (iNOS) on 3days after reperfusion (dpr) in ischemic rat brain. iNOS expression almost disappeared on 7dpr when transforming growth factor-β1 (TGF-β1) expression was robustly increased. After transient incubation with TGF-β1 for 24h, rat primary microglial cells were incubated with lipopolysaccharide (LPS) and released NO level was measured. The NO release was persistently suppressed even 72h after removal of TGF-β1. The sustained TGF-β1 effects were not attributable to microglia-derived endogenous TGF-β1, as revealed by TGF-β1 knockdown and in vitro quantification studies. Then, boiled supernatants prepared from ischemic brain tissues showed the similar sustained inhibitory effects on LPS-treated microglial cells that were prevented by the TGF-β1 receptor-selective blocker SB525334. After incubation with TGF-β1 for 24h and its subsequent removal, LPS-induced phosphorylation of IκB kinases (IKKs), IκB degradation, and NFκB nuclear translocation were inhibited in a sustained manner. SB525334 abolished all these effects of TGF-β1. In consistent with the in vitro results, phosphorylated IKK-immunoreactivity was abundant in MG/MPs in ischemic brain lesion on 3dpr, whereas it was almost disappeared on 7dpr. The findings suggest that abundantly produced TGF-β1 in ischemic brain displays sustained anti-inflammatory effects on microglial cells by persistently inhibiting endogenous Toll-like receptor ligand-induced IκB degradation.

Fibroblasts Promote Inflammation and Pain via IL-1α Induction of the Monocyte Chemoattractant Chemokine (C-C Motif) Ligand 2

Fibroblasts persist within fibrotic scar tissue and exhibit considerable phenotypic and functional plasticity. Herein, we hypothesized that scar-associated fibroblasts may be a source of stress-induced inflammatory exacerbations and pain. To test this idea, we used a human model of surgery-induced fibrosis, total knee arthroplasty (TKA). Using a combination of tissue protein expression profiling and bioinformatics, we discovered that many months after TKA, the fibrotic joint exists in a state of unresolved chronic inflammation. Moreover, the infrapatellar fat pad, a soft tissue that becomes highly fibrotic in the post-TKA joint, expresses multiple inflammatory mediators, including the monocyte chemoattractant, chemokine (C-C motif) ligand (CCL) 2, and the innate immune trigger, IL-1α. Fibroblasts isolated from the post-TKA fibrotic infrapatellar fat pad express the IL-1 receptor and on exposure to IL-1α polarize to a highly inflammatory state that enables them to stimulate the recruitment of monocytes. Blockade of fibroblast CCL2 or its transcriptional regulator NF-κB prevented IL-1α-induced monocyte recruitment. Clinical investigations discovered that levels of patient-reported pain in the post-TKA joint correlated with concentrations of CCL2 in the joint tissue, such that the chemokine is effectively a pain biomarker in the TKA patient. We propose that an IL-1α-NF-κB-CCL2 signaling pathway, operating within scar-associated fibroblasts, may be therapeutically manipulated for alleviating inflammation and pain in fibrotic joints and other tissues.

Schisandrol B and schisandrin B inhibit TGFβ1-mediated NF-κB activation via a Smad-independent mechanism

Aberrant transforming growth factor β1 (TGFβ1) signaling plays a pathogenic role in the development of vascular fibrosis. We have reported that Schisandra chinensis fruit extract (SCE), which has been used as a traditional oriental medicine, suppresses TGFβ1-mediated phenotypes in vascular smooth muscle cells (VSMCs). However, it is still largely unknown about the pharmacologic effects of SCE on various TGFβ1 signaling components. In this study, we found that SCE attenuated TGFβ1-induced NF-κB activation and nuclear translocation in VSMCs. Among the five active ingredients of SCE that were examined, schisandrol B (SolB) and schisandrin B (SchB) most potently suppressed TGFβ1-mediated NF-κB activation. In addition, SolB and SchB effectively inhibited IKKα/β activation and IκBα phosphorylation in TGFβ1-treated VSMCs. The pharmacologic effects of SolB and SchB on NF-κB activation were independent of the Smad-mediated canonical pathway. Therefore, our study demonstrates that SCE and its active constituents SolB and SchB suppress TGFβ1-mediated NF-κB signaling pathway in a Smad-independent mechanism. Our results may help further investigations to develop novel multi-targeted therapeutic strategies that treat or prevent vascular fibrotic diseases.

Celastrol improves self-renewal and differentiation of human tendon-derived stem cells by suppressing Smad7 through hypoxia

BACKGROUND

We aimed to evaluate the potential enhancing effect of celastrol on the stemness of human tendon-derived stem cells (hTSCs) in vitro and the underlying molecular mechanisms.

METHODS

The capability of hTSC self-renewal was assessed by cell proliferation and colony formation as determined with the CCK-8 kit. Adipogenesis, chondrogenesis, and osteogenesis were determined by Oil Red O, Alcian Blue, and Alizarin Red staining, respectively. The relative mRNA levels of Sox9, PPARγ, Runx2, Smad7, and HIF1α were determined by real-time polymerase chain reaction (PCR). The levels of Smad7 and HIF1α protein were measured by immunoblotting. The chromatin immunoprecipitation (ChIP) assay was used to assess the direct binding of HIF1α to the Smad7 promoter. Suppression of Smad7 induced by hypoxia was examined using the luciferase reporter assay.

RESULTS

We found that treatment with celastrol resulted in improvement in both the multi-differentiation potential and self-renewal capability of hTSCs. Celastrol elicited hypoxia and subsequently suppressed the expression of Smad7 through direct association with the hypoxia response element consensus sequence. Further, we demonstrated that both Smad7 and HIF1α were involved in the beneficial effects of celastrol on the differentiation and self-renewal of hTSCs.

CONCLUSIONS

We demonstrated the positive effect of celastrol on the stemness of hTSCs and elucidated the essential role of the HIF1α-Smad7 pathway in this process.

Separation of cell survival, growth, migration, and mesenchymal transdifferentiation effects of fibroblast secretome on tumor cells of head and neck squamous cell carcinoma

Fibroblasts play a central role in tumor invasion, recurrence, and metastasis in head and neck squamous cell carcinoma. The aim of this study was to investigate the influence of tumor cell self-produced factors and paracrine fibroblast–secreted factors in comparison to indirect co-culture on cancer cell survival, growth, migration, and epithelial–mesenchymal transition using the cell lines SCC-25 and human gingival fibroblasts. Thereby, we particularly focused on the participation of the fibroblast-secreted transforming growth factor beta-1.Tumor cell self-produced factors were sufficient to ensure tumor cell survival and basic cell growth, but fibroblast-secreted paracrine factors significantly increased cell proliferation, migration, and epithelial–mesenchymal transition–related phenotype changes in tumor cells. Transforming growth factor beta-1 generated individually migrating disseminating tumor cell groups or single cells separated from the tumor cell nest, which were characterized by reduced E-cadherin expression. At the same time, transforming growth factor beta-1 inhibited tumor cell proliferation under serum-starved conditions. Neutralizing transforming growth factor beta antibody reduced the cell migration support of fibroblast-conditioned medium. Transforming growth factor beta-1 as a single factor was sufficient for generation of disseminating tumor cells from epithelial tumor cell nests, while other fibroblast paracrine factors supported tumor nest outgrowth. Different fibroblast-released factors might support tumor cell proliferation and invasion, as two separate effects.

Cancer stem cell and its niche in malignant progression of oral potentially malignant disorders

OBJECTIVE

The purpose of this study was to determine association between cancer stem cells (CSCs) and their niche with progression of oral potentially malignant disorders.

MATERIALS AND METHODS

Patients with histologically confirmed oral potentially malignant disorders, stratified into high/low risk lesions based on the degree of dysplasia and oral cancer were included in this study. Immunohistochemical profiling of markers of CSCs (CD44), endothelial cells (CD31) and CSC-vascular niche cross-talk (CXCR4 and SDF1) were carried out. Statistical analysis was performed to correlate the relationship of markers with histopathology grade (ANOVA, and χ² test, unpaired t test) using GraphPad InStat v3.06.

RESULTS

The study included 550 samples (349 patients) and analysis showed progressive increase in expression levels of CSC and its niche markers with increase in grade of dysplasia as compared to the normal cohort (p < 0.05). Co-expression analysis revealed that, in comparison to the normal cohort, a larger percentage of patients showed increased expression of CD31 and CD44 (CD31^high/CD44^high; p < 0.05) and of CXCR4 and SDF1 (CXCR4^high/SDF1^high; p = 0.04), suggesting an association of the CSCs and the vascular niche. Further, distribution of patients with CD44^high/CXCR4^high (p < 0.05) and CD31^high/SDF1^high (p = 0.01) was significantly increased in the high-risk group (18%), suggesting a correlation between CD44⁺/CXCR4⁺ cells, the vascular niche and progression of oral dysplastic lesions.

CONCLUSION

The increased expression of CSCs, the vascular niche and their cross talk markers are associated with increase in severity of dysplasia suggesting their role in the progression of oral potentially malignant disorders and may hence be used in identifying high-risk OPMD.

Knockdown of IARS2 suppressed growth of gastric cancer cells by regulating the phosphorylation of cell cycle-related proteins

The purpose of the article is to investigate the role of IARS2 in proliferation, apoptosis, and cell cycle of gastric cancer (GC) cells in vitro. The IARS2-shRNA lentiviral vector was established and used to infect the GC cell line AGS. qRT-PCR and Western blot were employed to determine the efficiency of IARS2 knockdown. The effects of IARS2 knockdown on cell proliferation, cell clone formation, and cell cycle were assessed by MTT assay, colony formation assay, and flow cytometer analysis, respectively. Finally, a PathScan Antibody Array Kit was used to detect the expression levels of cell cycle-related proteins after IARS2 knockdown in AGS cells to elucidate the underlying mechanisms. Compared with negative control group, IARS2 was significantly knocked down by transfection with lentivirus encoding shRNA of IARS2 in AGS cells. IARS2 knockdown significantly inhibited the proliferation and colony formation ability and induced cycle arrest at G2/M phase of AGS cells. IARS2 knockdown significantly decreased the expression levels of phosphorylation of (p-Smad2), p-SAPK/JUK, cleavage-Caspase-7, and p-TAK1, but increased the expression levels of p-53 and cleavage-PARP in AGS cells compared to shCtrl group. We demonstrated that IARS2 knockdown inhibits proliferation, suppresses colony formation, and causes cell cycle arrest in AGS cells. We also found that IARS2 regulates key molecules of cell apoptosis-related signaling pathway.

Interleukin 1 β-induced SMAD2/3 linker modifications are TAK1 dependent and delay TGFβ signaling in primary human mesenchymal stem cells

BACKGROUND

Chondrogenic differentiation of mesenchymal stem cells (MSC) requires transforming growth factor beta (TGFβ) signaling. TGFβ binds to the type I receptor activin-like kinase (ALK)5 and results in C-terminal SMAD2/3 phosphorylation (pSMAD2/3C). In turn pSMAD2/3C translocates to the nucleus and regulates target gene expression. Inflammatory mediators are known to exert an inhibitory effect on MSC differentiation. In this study we investigated the effect of interleukin 1 β (IL1β) on SMAD2/3 signaling dynamics and post-translational modifications.

RESULTS

Co-stimulation of MSC with TGFβ and IL1β did not affect peak pSMAD2C levels at 1h post-stimulation. Surprisingly, SMAD3 transcriptional activity, as determined by the CAGA₁₂-luciferase reporter construct, was enhanced by co-stimulation of TGFβ and IL1β compared to TGFβ alone. Furthermore, IL1β stimulation induced CAGA₁₂-luciferase activity in a SMAD dependent way. As SMAD function can be modulated independent of canonical TGFβ signaling through the SMAD linker domain, we studied SMAD2 linker phosphorylation at specific threonine and serine residues. SMAD2 linker threonine and serine modifications were observed within 1h following TGFβ, IL1β or TGFβ and IL1β stimulation. Upon co-stimulation linker modified SMAD2 accumulated in the cytoplasm and SMAD2/3 target gene transcription (ID1, JUNB) at 2-4h was inhibited. A detailed time course analysis of IL1β-induced SMAD2 linker modifications revealed a distinct temperospatial pattern compared to TGFβ. Co-stimulation with both factors resulted in a similar kinetic profile as TGFβ alone. Nevertheless, IL1β did subtly alter TGFβ-induced pSMAD2C levels between 8 and 24h post-stimulation, which was reflected by TGFβ target gene expression (PAI1, JUNB). Direct evidence for the importance of SMAD3 linker modifications for the effect of IL1β on TGFβ signaling was obtained by over-expression of SMAD3 or a SMAD3 linker phospho-mutant. Finally, an inhibitor screening was performed to identify kinases involved in SMAD2/3 linker modifications. We identified TAK1 kinase activity as crucial for IL1β-induced SMAD2 linker modifications and CAGA₁₂-luciferase activity.

CONCLUSIONS

TGFβ and IL1β signaling interact at the SMAD2/3 level in human primary MSC. Down-stream TGFβ target genes were repressed by IL1β independent of C-terminal SMAD2 phosphorylation. We demonstrate that SMAD2/3 linker modifications are required for this interplay and identified TAK1 as a crucial mediator of IL1β-induced TGFβ signal modulation.

Combination of Hypertension Along with a High Fat and Cholesterol Diet Induces Severe Hepatic Inflammation in Rats via a Signaling Network Comprising NF-κB, MAPK, and Nrf2 Pathways

Populations with essential hypertension have a high risk of nonalcoholic steatohepatitis (NASH). In this study, we investigated the mechanism that underlies the progression of hypertension-associated NASH by comparing differences in the development of high fat and cholesterol (HFC) diet-induced NASH among three strains of rats, i.e., two hypertensive strains comprising spontaneously hypertensive rats and the stroke-prone spontaneously hypertensive 5/Dmcr, and the original Wistar Kyoto rats as the normotensive control. We investigated histopathological changes and molecular signals related to inflammation in the liver after feeding with the HFC diet for 8 weeks. The diet induced severe lobular inflammation and fibrosis in the livers of the hypertensive rats, whereas it only caused mild steatohepatitis in the normotensive rats. An increased activation of proinflammatory signaling (transforming growth factor-β1/mitogen-activated protein kinases pathway) was observed in the hypertensive strains fed with the HFC diet. In addition, the HFC diet suppressed the nuclear factor erythroid 2-related factor 2 pathway in the hypertensive rats and led to lower increases in the hepatic expression of heme oxygenase-1, which has anti-oxidative and anti-inflammatory activities. In conclusion, these signaling pathways might play crucial roles in the development of hypertension-associated NASH.

NF-κB regulates GDF-15 to suppress macrophage surveillance during early tumor development

Macrophages are attracted to developing tumors and can participate in immune surveillance to eliminate neoplastic cells. In response, neoplastic cells utilize NF-κB to suppress this killing activity, but the mechanisms underlying their self-protection remain unclear. Here, we report that this dynamic interaction between tumor cells and macrophages is integrally linked by a soluble factor identified as growth and differentiation factor 15 (GDF-15). In vitro, tumor-derived GDF-15 signals in macrophages to suppress their proapoptotic activity by inhibiting TNF and nitric oxide (NO) production. In vivo, depletion of GDF-15 in Ras-driven tumor xenografts and in an orthotopic model of pancreatic cancer delayed tumor development. This delay correlated with increased infiltrating antitumor macrophages. Further, production of GDF-15 is directly regulated by NF-κB, and the colocalization of activated NF-κB and GDF-15 in epithelial ducts of human pancreatic adenocarcinoma supports the importance of this observation. Mechanistically, we found that GDF-15 suppresses macrophage activity by inhibiting TGF-β-activated kinase (TAK1) signaling to NF-κB, thereby blocking synthesis of TNF and NO. Based on these results, we propose that the NF-κB/GDF-15 regulatory axis is important for tumor cells in evading macrophage immune surveillance during the early stages of tumorigenesis.

Endothelial fibrosis induced by suppressed STAT3 expression mediated by signaling involving the TGF-β1/ALK5/Smad pathway

During systemic inflammatory pathologies, mediators of inflammation circulate in the bloodstream and interact with endothelial cells (ECs), resulting in endothelial dysfunction that maintains and enhances the pathological condition. Inflammatory mediators change the protein expression profile of ECs, which become activated fibroblasts via endothelial-to-mesenchymal transition. This process is characterized by downregulated endothelial proteins and strongly upregulated fibrotic-specific genes and extracellular matrix-forming proteins. The main inductor of endothelial fibrosis is transforming growth factor-β1 (TGF-β1), which acts through the TGF-β1/activin receptor-like kinase 5 (ALK5)/Smads intracellular signaling pathway. The signal transducer and activator of transcription 3 (STAT3) is also involved in fibrosis in several tissues (e.g. heart and vascular system), where STAT3 signaling decreases TGF-β1-induced responses by directly interacting with Smad proteins, suggesting that decreased STAT3 could induce TGF-β1-mediated fibrosis. However, it is unknown if suppressed STAT3 expression induces EC fibrosis through a mechanism involving the TGF-β signaling pathway. The present study evaluated the fibrotic actions of STAT3 suppression in ECs and investigated TGF-β1/ALK5/Smad4 signaling pathway participation. Suppressed STAT3 expression stimulated fibrotic conversion in ECs, as mediated by protein expression reprograming that decreased endothelial marker expression and increased fibrotic and extracellular matrix protein levels. The potential mechanism underlying these changes was dependent on TGF-β1 secretion, the ALK5 activation pathway, and Smad4 translocation into the nucleus. We conclude that suppressed STAT3 expression converts ECs into activated fibroblasts via TGF-β1/ALK5/Smad4 signaling pathway involvement.

Elevated NF-κB signaling in Asherman syndrome patients and animal models

Asherman syndrome (intrauterine adhesion) is often associated with menstrual abnormalities, infertility and recurrent miscarriage in female. Currently the molecular mechanism regulating the pathogenesis of Asherman syndrome is not known. Here we revealed that the inflammatory factor NF-κB expression is significantly elevated in the endometrial samples of Asherman syndrome patients. To further study the molecular mechanisms, we established an Asherman syndrome rat model and confirmed the important role of NF-κB in the pathogenesis of Asherman syndrome. In addition, our rat model provided direct evidence that intrauterine adhesion results in impaired pregnancy, supporting the clinical association between intrauterine adhesion and mis-regulated pregnancy. Our result identified NF-κB as a novel pathogenesis factor of Asherman syndrome and provided new insights for the prevention and treatment of intrauterine adhesions in Asherman syndrome patients.

Transforming growth factor-β signaling in systemic sclerosis

Systemic sclerosis (SSc) is a complex, multiorgan autoimmune disease of unknown etiology. Manifestation of the disease results from an interaction of three key pathologic features including irregularities of the antigen-specific immune system and the non-specific immune system, resulting in autoantibody production, vascular endothelial activation of small blood vessels, and tissue fibrosis as a result of fibroblast dysfunction. Given the heterogeneity of clinical presentation of the disease, a lack of universal models has impeded adequate testing of potential therapies for SSc. Regardless, recent research has elucidated the roles of various ubiquitous molecular mechanisms that contribute to the clinical manifestation of the disease. Transforming growth factor β (TGF-β) has been identified as a regulator of pathological fibrogenesis in SSc. Various processes, including cell growth, apoptosis, cell differentiation, and extracellular matrix synthesis are regulated by TGF-β, a type of cytokine secreted by macrophages and many other cell types. Understanding the essential role TGF-β pathways play in the pathology of systemic sclerosis could provide a potential outlet for treatment and a better understanding of this severe disease.

Testes-specific protease 50 promotes cell proliferation via inhibiting activin signaling

Testes-specific protease 50 (TSP50), a novelly identified oncogene, has the capacity to induce cell proliferation, cell invasion and tumor growth. Further studies indicated that CAGA-luc (an activin-responsive reporter construct) reporter activity could be significantly suppressed by TSP50 overexpression, implying that the activin signaling may participate in TSP50-mediated cell proliferation. Here, we reported that TSP50 had an inhibitory effect on activin signaling. Mechanistic studies revealed that TSP50 could interact with ActRIIA, inhibit activin typeIreceptor (ActRIB) phosphorylation, repress Smad2/3 nuclear accumulation and finally promote cell proliferation by reducing the expression of activin signal target gene p27. Additionally, we found that ActRIB activation could reverse TSP50-mediated cell proliferation and tumor growth. Furthermore, analysis of human breast cancer specimens by immunohistochemistry indicated that TSP50 expression was negatively related to p-Smad2/3 and p27 protein levels. Most importantly, breast cancer diagnosis-related indicators such as tumor size, tumor grade, estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor receptor 2 (HER-2) levels, were correlated well with TSP50/p-Samd2/3 and TSP50/p27 expression status. Thus, our studies revealed a novel regulatory mechanism underlying TSP50-induced cell proliferation and provided a new favorable intervention target for the treatment of breast cancer.

Ameliorative Effect of Coenzyme Q10 and/or Candesartan on Carboplatin-Induced Nephrotoxicity: Roles of Apoptosis, Transforming Growth Factor-Β1, Nuclear Factor Kappa-B And The Nrf2/HO-1 Pathway

Background:

Carboplatin is a drug that is used for treatment of many types of cancer. However, it may produce serious nephrotoxicity. Candesartan is angiotensin II receptor antagonist employed mainly for control of hypertension. Coenzyme Q10 (CoQ10) is a fat-soluble substance which was proven to have potent antioxidant and anti-inflammatory properties.

Aim:

Our aim was to study the effects of candesartan and/or CoQ10 on carboplatin-induced nephrotoxicity in mice.

Methods:

Sixty mice were divided into 6 equal groups: Control untreated; carboplatin; carboplatin + candesartan; carboplatin + CoQ10; carboplatin + carboxymethyl cellulose; and carboplatin + candesartan + CoQ10 group. Kidney weight/body weight ratio, blood urea, serum creatinine, creatinine clearance, urinary N-acetyl beta-D-glucosaminidase (NAG), gamma glutamyl transpeptidase (GGT) and the urinary albumin excretion rate (UAER) were determined. Renal tissue catalase (CAT), glutathione reductase (GR), nuclear factor (erythroid-derived 2)-like 2 (Nrf2), heme oxygenase-1 (HO-1), transforming growth factor beta-1 (TGF-β1), tumor necrosis factor alpha (TNF-α) and interleukin 6 (IL-6) were also determined, along with mitochondrial complex I activity. In addition, portions of the kidney were subjected to histopathological and immunohistochemical examination.

Results:

Candesartan and/or CoQ10 induced significant improvement of renal and mitochondrial functions with significant increase in tissue CAT, GR, Nrf2 and HO-1 content associated with significant decrease in the kidney weight/body weight ratio, tissue TGF-β1, TNF-α and IL-6 and alleviation of the histopathological and immunohistochemical changes as compared to carboplatin alone group. These effects were more significant in candesartan/CoQ10 combination group compared to either candesartan or CoQ10 alone.

Conclusion:

Candesartan/CoQ10 combination might represent a beneficial therapeutic modality for amelioration of carboplatin-induced nephrotoxicity.

TGF-β, Bone Morphogenetic Protein, and Activin Signaling and the Tumor Microenvironment

The cellular and noncellular components surrounding the tumor cells influence many aspects of tumor progression. Transforming growth factor β (TGF-β), bone morphogenetic proteins (BMPs), and activins have been shown to regulate the phenotype and functions of the microenvironment and are attractive targets to attenuate protumorigenic microenvironmental changes. Given the pleiotropic nature of the cytokines involved, a full understanding of their effects on numerous cell types in many contexts is necessary for proper clinical intervention. In this review, we will explore the various effects of TGF-β, BMP, and activin signaling on stromal phenotypes known to associate with cancer progression. We will summarize these findings in the context of their tumor suppressive or promoting effects, as well as the molecular changes that these cytokines induce to influence stromal phenotypes.

MicroRNA-15a inhibition protects against hypoxia/reoxygenation-induced apoptosis of cardiomyocytes by targeting mothers against decapentaplegic homolog 7

Myocardial ischemia/reperfusion (I/R) injury is a major pathological process in coronary heart disease and cardiac surgery, and is associated with aberrant microRNA (miR) expression. Previous studies have demonstrated that inhibition of miR-15a expression may ameliorate I/R-induced myocardial injury. In the present study, the potential role and underlying mechanism of miR-15a in hypoxia/reoxygenation-induced apoptosis of cardiomyocytes was investigated. Myocardial I/R was simulated in cultured H9c2 cells by 24 h hypoxia followed by 24 h reoxygenation. Using recombinant lentivirus vectors, the inhibition of miR-15a was indicated to significantly reduce cardiomyocyte apoptosis and release of lactate dehydrogenase and malondialdehyde. Conversely, upregulated miR-15a expression was pro-apoptotic. Mothers against decapentaplegic homolog 7 (SMAD7) was identified by bioinformatics analysis as a potential target of miR-15a. Luciferase reporter assays and western blotting for endogenous SMAD7 protein indicated that miR-15a inhibited SMAD7 expression via its 3′-untranslated region. Nuclear levels of nuclear factor-κB (NF-κB) p65 were increased by miR-15a expression and decreased by miR-15a inhibition, which is consistent with the possibility that the inhibition of SMAD7 by miR-15a results in NF-κB activation. These findings suggested that the therapeutic effects of miR-15a inhibition on I/R injury may potentially be explained by its ability to release SMAD-7-dependent NF-κB inhibition. This may provide evidence for miR-15a as a potential therapeutic target for the treatment of cardiac I/R injury.

IL6-mediated inflammatory loop reprograms normal to epithelial-mesenchymal transition+ metastatic cancer stem cells in preneoplastic liver of transforming growth factor beta-deficient β2-spectrin+/- mice

Hepatocellular carcinoma (HCC) is the second-leading cause of cancer-related deaths worldwide with a poor survival rate. As many as 40% of HCCs are clonal, with alteration of key tumor-suppressor pathways in stem cells as the primary cause of HCC initiation. However, mechanisms that generate metastatic stem cells in preneoplastic liver tissue are not well understood. We hypothesized that chronic inflammation is a major driver of the transformation of genetically defective liver stem cells (LSCs) into highly metastatic liver cancer cells in premalignant liver tissue. We developed models of chronic inflammation in wild-type (WT) and β2-spectrin (β2SP)^+/- (SPTBN1) mice. CD133⁺ LSCs derived from preneoplastic livers of β2SP^+/- mice treated with interleukin-6 (pIL6; ^IL6 β2SP^+/- LSCs) were highly tumorigenic and metastatic, whereas those derived from WT mice treated with pIL6 (^IL6 WT LSCs) had significantly less proliferation and no tumorigenic properties. ^IL6 β2SP^+/- LSCs not only exhibited nuclear localization of Twist and Slug, markers of epithelial-mesenchymal transition (EMT), but also constitutive activation of nuclear factor kappa B (NFκB; RELA). Knockdown of NFκB decreased the EMT phenotypes and metastatic capacity of these cells. NFκB in ^IL6 β2SP^+/- LSCs was activated by transforming growth factor β (TGFβ)-activated kinase 1 (TAK1; MAP3K7), which is associated with poor survival in HCC and interleukin-6 (IL6) expression. The amount of constitutively activated NFκB increased dramatically from normal to cirrhotic to HCC tissues from human patients.

CONCLUSION

IL6-mediated inflammation programs constitutive activation of the TAK1-NFκB signaling cascade in CD133⁺ LSCs, and this program interacts with deficient TGFβ signaling, thereby accelerating the transformation of normal LSCs to metastatic cancer stem cells (mCSCs). Indeed, this study delineates the development of EMT-positive mCSCs in HCC-free liver tissue upon chronic inflammation. (Hepatology 2017;65:1222-1236).

TGF-β1 signaling pathway serves a role in HepG2 cell regulation by affecting the protein expression of PCNA, gankyrin, p115, XIAP and survivin

The transforming growth factor-β (TGF-β) signaling pathway serves a key role in the pathogenesis of liver cancer. To investigate the association between TGF-β1 and the following proteins: Proliferating cell nuclear antigen (PCNA), gankyrin, general vesicular transport factor p115 (p115), X-linked inhibitor of apoptosis protein (XIAP) and survivin, HepG2 liver cancer cells were transfected with small interfering RNA (siRNA) directed against TGF-β1, or were treated with exogenous TGF-β1. TGF-β1 protein expression levels were assessed at 72 and 96 h using western blotting, cell growth was evaluated using a Cell Counting kit-8 assay, and flow cytometry was used to examine cell cycle distribution and apoptosis. In addition, PCNA, gankyrin, p115, XIAP and survivin protein levels were evaluated using western blotting. TGF-β1 protein expression levels were decreased at 72 and 96 h following siRNA transfection, indicating that the siRNA against TGF-β1 was effective. In the TGF-β1-knockdown group, the HepG2 cells exhibited G₁ or S-phase cell cycle arrest; therefore, the number of G₂-phase cells was decreased, cell growth was inhibited and apoptotic peaks were observed. By contrast, no significant alteration in cell cycle distribution or apoptosis was observed in the cells treated with exogenous TGF-β1. In the exogenous TGF-β1 group, PCNA and XIAP protein expression levels were increased, whereas gankyrin, p115 and survivin protein expression was observed to be dependent on the duration of treatment. By contrast, PCNA, gankyrin, XIAP and survivin protein expression decreased following TGF-β1 knockdown; however, p115 protein expression increased. In conclusion, the TGF-β1 signaling pathway may affect cell growth, cell cycle distribution and apoptosis through the regulation of PCNA, gankyrin, p115, XIAP and survivin protein expression in liver cancer. The results of the present study may improve the current understanding of the role of the TGF-β signaling pathway during the pathogenesis of liver cancer.

RETRACTED: Ameliorative potential of linagliptin and/or calcipotriol on bleomycin-induced lung fibrosis: In vivo and in vitro study

This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/our-business/policies/article-withdrawal). This article has been retracted due to the authors’ plagiarism of text and images from the work of Eman Said Abd-Elkhalek, Hatem Abdel-Rahman Salem, Ghada Mohamed SuddeK, Marwa Ahmed Zaghloul and Ramy Ahmed Abdel-Salam, Faculties of Pharmacy and Medicine, Mansoura University, Mansoura, Egypt.

Gene regulatory network underlying the immortalization of epithelial cells

BACKGROUND

Tumorigenic transformation of human epithelial cells in vitro has been described experimentally as the potential result of spontaneous immortalization. This process is characterized by a series of cell-state transitions, in which normal epithelial cells acquire first a senescent state which is later surpassed to attain a mesenchymal stem-like phenotype with a potentially tumorigenic behavior. In this paper we aim to provide a system-level mechanistic explanation to the emergence of these cell types, and to the time-ordered transition patterns that are common to neoplasias of epithelial origin. To this end, we first integrate published functional and well-curated molecular data of the components and interactions that have been found to be involved in such cell states and transitions into a network of 41 molecular components. We then reduce this initial network by removing simple mediators (i.e., linear pathways), and formalize the resulting regulatory core into logical rules that govern the dynamics of each of the network components as a function of the states of its regulators.

RESULTS

Computational dynamic analysis shows that our proposed Gene Regulatory Network model recovers exactly three attractors, each of them defined by a specific gene expression profile that corresponds to the epithelial, senescent, and mesenchymal stem-like cellular phenotypes, respectively. We show that although a mesenchymal stem-like state can be attained even under unperturbed physiological conditions, the likelihood of converging to this state is increased when pro-inflammatory conditions are simulated, providing a systems-level mechanistic explanation for the carcinogenic role of chronic inflammatory conditions observed in the clinic. We also found that the regulatory core yields an epigenetic landscape that restricts temporal patterns of progression between the steady states, such that recovered patterns resemble the time-ordered transitions observed during the spontaneous immortalization of epithelial cells, both in vivo and in vitro.

CONCLUSION

Our study strongly suggests that the in vitro tumorigenic transformation of epithelial cells, which strongly correlates with the patterns observed during the pathological progression of epithelial carcinogenesis in vivo, emerges from underlying regulatory networks involved in epithelial trans-differentiation during development.

Cancer-associated fibroblasts enact field cancerization by promoting extratumoral oxidative stress

Histological inspection of visually normal tissue adjacent to neoplastic lesions often reveals multiple foci of cellular abnormalities. This suggests the presence of a regional carcinogenic signal that spreads oncogenic transformation and field cancerization. We observed an abundance of mutagenic reactive oxygen species in the stroma of cryosectioned patient tumor biopsies, indicative of extratumoral oxidative stress. Diffusible hydrogen peroxide (H₂O₂) was elevated in the conditioned medium of cultured skin epithelia at various stages of oncogenic transformation, and H₂O₂ production increased with greater tumor-forming and metastatic capacity of the studied cell lines. Explanted cancer-associated fibroblasts (CAFs) also had higher levels of H₂O₂ secretion compared with normal fibroblasts (FIBs). These results suggest that extracellular H₂O₂ acts as a field effect carcinogen. Indeed, H₂O₂-treated keratinocytes displayed decreased phosphatase and tensin homolog (PTEN) and increased Src activities because of oxidative modification. Furthermore, treating FIBs with CAF-conditioned medium or exogenous H₂O₂ resulted in the acquisition of an oxidative, CAF-like state. In vivo, the proliferative potential and invasiveness of composite tumor xenografts comprising cancerous or non-tumor-forming epithelia with CAFs and FIBs could be attenuated by the presence of catalase. Importantly, we showed that oxidatively transformed FIBs isolated from composite tumor xenografts retained their ability to promote tumor growth and aggressiveness when adoptively transferred into new xenografts. Higher H₂O₂ production by CAFs was contingent on impaired TGFβ signaling leading to the suppression of the antioxidant enzyme glutathione peroxidase 1 (GPX1). Finally, we detected a reduction in Smad3, TAK1 and TGFβRII expression in a cohort of 197 clinical squamous cell carcinoma (SCC) CAFs, suggesting that impaired stromal TGFβ signaling may be a clinical feature of SCC. Our study indicated that CAFs and cancer cells engage redox signaling circuitries and mitogenic signaling to reinforce their reciprocal relationship, suggesting that future anticancer approaches should simultaneously target ligand receptor and redox-mediated pathways.

Signaling Cross Talk between TGF-β/Smad and Other Signaling Pathways

Cytokines of the transforming growth factor β (TGF-β) family, including TGF-βs, bone morphogenic proteins (BMPs), activins, and Nodal, play crucial roles in embryonic development and adult tissue homeostasis by regulating cell proliferation, survival, and differentiation, as well as stem-cell self-renewal and lineage-specific differentiation. Smad proteins are critical downstream mediators of these signaling activities. In addition to regulating the transcription of direct target genes of TGF-β, BMP, activin, or Nodal, Smad proteins also participate in extensive cross talk with other signaling pathways, often in a cell-type- or developmental stage-specific manner. These combinatorial signals often produce context-, time-, and location-dependent biological outcomes that are critical for development. This review discusses recent progress in our understanding of the cross talk between Smad proteins and signaling pathways of Wnt, Notch, Hippo, Hedgehog (Hh), mitogen-activated protein (MAP), kinase, phosphoinositide 3-kinase (PI3K)-Akt, nuclear factor κB (NF-κB), and Janus kinase/signal transducers and activators of transcription (JAK/STAT) pathways.

Signaling Cross Talk between TGF-β/Smad and Other Signaling Pathways

Cytokines of the transforming growth factor β (TGF-β) family, including TGF-βs, bone morphogenic proteins (BMPs), activins, and Nodal, play crucial roles in embryonic development and adult tissue homeostasis by regulating cell proliferation, survival, and differentiation, as well as stem-cell self-renewal and lineage-specific differentiation. Smad proteins are critical downstream mediators of these signaling activities. In addition to regulating the transcription of direct target genes of TGF-β, BMP, activin, or Nodal, Smad proteins also participate in extensive cross talk with other signaling pathways, often in a cell-type- or developmental stage-specific manner. These combinatorial signals often produce context-, time-, and location-dependent biological outcomes that are critical for development. This review discusses recent progress in our understanding of the cross talk between Smad proteins and signaling pathways of Wnt, Notch, Hippo, Hedgehog (Hh), mitogen-activated protein (MAP), kinase, phosphoinositide 3-kinase (PI3K)-Akt, nuclear factor κB (NF-κB), and Janus kinase/signal transducers and activators of transcription (JAK/STAT) pathways.

Compounds From Celastraceae Targeting Cancer Pathways and Their Potential Application in Head and Neck Squamous Cell Carcinoma: A Review

Squamous cell carcinoma of the head and neck is one of the most common cancer types worldwide. It initiates on the epithelial lining of the upper aerodigestive tract, at most instances as a consequence of tobacco and alcohol consumption. Treatment options based on conventional therapies or targeted therapies under development have limited efficacy due to multiple genetic alterations typically found in this cancer type. Natural products derived from plants often possess biological activities that may be valuable in the development of new therapeutic agents for cancer treatment. Several genera from the family Celastraceae have been studied in this context. This review reports studies on chemical constituents isolated from species from the Celastraceae family targeting cancer mechanisms studied to date. These results are then correlated with molecular characteristics of head and neck squamous cell carcinoma in an attempt to identify constituents with potential application in the treatment of this complex disease at the molecular level.

STRAP Acts as a Scaffolding Protein in Controlling the TLR2/4 Signaling Pathway

The WD40-repeat protein serine/threonine kinase receptor-associated protein (STRAP) is involved in the regulation of several biological processes, including cell proliferation and apoptosis, in response to various stresses. Here, we show that STRAP is a new scaffold protein that functions in Toll-like receptor (TLR)-mediated immune responses. STRAP specifically binds transforming growth factor β-activated kinase 1 (TAK1) and IκB kinase alpha (IKKα) along with nuclear factor-κB (NF-κB) subunit p65, leading to enhanced association between TAK1, IKKα, and p65, and subsequent facilitation of p65 phosphorylation and nuclear translocation. Consequently, the depletion of STRAP severely impairs interleukin-6 (IL-6), tumor necrosis factor alpha (TNF-α), and IL-1β production, whereas its overexpression causes a significant increase in the secretion of these pro-inflammatory cytokines by TLR2 or TLR4 agonist-stimulated macrophages. Notably, STRAP translocates to the nucleus and subsequently binds to NF-κB at later times after lipopolysaccharide (LPS) stimulation, resulting in prolonged IL-6 mRNA production. Moreover, the C-terminal region of STRAP is essential for its functional activity in facilitating IL-6 production. Collectively, these observations suggest that STRAP acts as a scaffold protein that positively contributes to innate host defenses against pathogen infections.

Pericyte MyD88 and IRAK4 control inflammatory and fibrotic responses to tissue injury

Fibrotic disease is associated with matrix deposition that results in the loss of organ function. Pericytes, the precursors of myofibroblasts, are a source of pathological matrix collagens and may be promising targets for treating fibrogenesis. Here, we have shown that pericytes activate a TLR2/4- and MyD88-dependent proinflammatory program in response to tissue injury. Similarly to classic immune cells, pericytes activate the NLRP3 inflammasome, leading to IL-1β and IL-18 secretion. Released IL-1β signals through pericyte MyD88 to amplify this response. Unexpectedly, we found that MyD88 and its downstream effector kinase IRAK4 intrinsically control pericyte migration and conversion to myofibroblasts. Specific ablation of MyD88 in pericytes or pharmacological inhibition of MyD88 signaling by an IRAK4 inhibitor in vivo protected against kidney injury by profoundly attenuating tissue injury, activation, and differentiation of myofibroblasts. Our data show that in pericytes, MyD88 and IRAK4 are key regulators of 2 major injury responses: inflammatory and fibrogenic. Moreover, these findings suggest that disruption of this MyD88-dependent pathway in pericytes might be a potential therapeutic approach to inhibit fibrogenesis and promote regeneration.

Intraarticular overexpression of Smad7 ameliorates experimental arthritis

Rheumatoid arthritis (RA) and Crohn's disease (CD) are autoimmune disorders with a crosstalk between their pathogenesis such as increased expression of TNF in the target organs. Despite a successful clinical trial with an oral Smad7 antisense oligonucleotide in CD, intraarticular (i.a.) modulation of Smad7 expression has not been performed in rheumatoid joint yet. In this study, contradictory to the findings in CD mucosa, higher levels of pSmad2/3 were found in RA synovium. In vitro experiments with synovial fibroblasts revealed that higher acetylated Smad7 expression was associated with lower activation status. Abundant expression of synovial pSmad2/3 with increased levels during the progression of arthritis was detected in collagen-induced arthritis (CIA) mice. To prove the concept that overexpressing Smad7 as a therapeutic strategy in rheumatoid joint, the i.a. injection of lentiviral vectors carrying Smad7 (LVSmad7) was carried out in CIA mice. In LVSmad7-injected joints, there were lower arthritis and histological scores with less synovitis, synovial hyperplasia and erosion on cartilage and bone as well as reduced IL-17 and TNF expression levels in comparison with other control groups. In conclusion, we demonstrate that lentiviral vector-mediated i.a. overexpression of Smad7 can ameliorate rheumatoid joint, implicating a pharmacological development of Smad7-based molecular strategy in RA.

NF-κB Pathways in the Pathogenesis of Multiple Sclerosis and the Therapeutic Implications

Nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) signaling pathways are involved in cell immune responses, apoptosis and infections. In multiple sclerosis (MS), NF-κB pathways are changed, leading to increased levels of NF-κB activation in cells. This may indicate a key role for NF-κB in MS pathogenesis. NF-κB signaling is complex, with many elements involved in its activation and regulation. Interestingly, current MS treatments are found to be directly or indirectly linked to NF-κB pathways and act to adjust the innate and adaptive immune system in patients. In this review, we will first focus on the intricacies of NF-κB signaling, including the activating pathways and regulatory elements. Next, we will theorize about the role of NF-κB in MS pathogenesis, based on current research findings, and discuss some of the associated therapeutic implications. Lastly, we will review four new MS treatments which interrupt NF-κB pathways—fingolimod, teriflunomide, dimethyl fumarate (DMF) and laquinimod (LAQ)—and explain their mechanisms, and the possible strategy for MS treatments in the future.

Rewiring of the apoptotic TGF-β-SMAD/NFκB pathway through an oncogenic function of p27 in human papillary thyroid cancer

Papillary thyroid carcinoma (PTC), the most frequent thyroid cancer, is characterized by low proliferation but no apoptosis, presenting frequent lymph-node metastasis. Papillary thyroid carcinoma overexpress transforming growth factor-beta (TGF-β). In human cells, TGF-β has two opposing actions: antitumoral through pro-apoptotic and cytostatic activities, and pro-tumoral promoting growth and metastasis. The switch converting TGF-β from a tumor-suppressor to tumor-promoter has not been identified. In the current study, we have quantified a parallel upregulation of TGF-β and nuclear p27, a CDK2 inhibitor, in samples from PTC. We established primary cultures from follicular epithelium in human homeostatic conditions (h7H medium). TGF-β-dependent cytostasis occurred in normal and cancer cells through p15/CDKN2B induction. However, TGF-β induced apoptosis in normal and benign but not in carcinoma cultures. In normal thyroid cells, TGF-β/SMAD repressed the p27/CDKN1B gene, activating CDK2-dependent SMAD3 phosphorylation to induce p50 NFκB-dependent BAX upregulation and apoptosis. In thyroid cancer cells, oncogene activation prevented TGF-β/SMAD-dependent p27 repression, and CDK2/SMAD3 phosphorylation, leading to p65 NFκB upregulation which repressed BAX, induced cyclin D1 and promoted TGF-β-dependent growth. In PTC samples from patients, upregulation of TGF-β, p27, p65 and cyclin D1 mRNA were significantly correlated, while the expression of the isoform BAX-β, exclusively transcribed in apoptotic cells, was negatively correlated. Additionally, combined ERK and p65 NFκB inhibitors reduced p27 expression and potentiated apoptosis in thyroid cancer cells while not affecting survival in normal thyroid cells. Our results therefore suggest that the oncoprotein p27 reorganizes the effects of TGF-β in thyroid cancer, explaining the slow proliferation but lack of apoptosis and metastatic behavior of PTC.

Inhibition of Transforming Growth Factor-β (TGF-β) Signaling by Scutellaria baicalensis and Fritillaria cirrhosa Extracts in Endometrial Cancer

Transforming growth factor-β (TGF-β), regulates cell proliferation, angiogenesis, metastasis, and is an inducer of epithelial-mesenchymal transition (EMT). Cancer cells exhibit activated TGF-β/SMAD signaling pathway and its inhibition is an attractive strategy for cancer treatment. The Chinese Herbs Scutellaria baicalensis (SB) and Fritillaria cirrhosa (FC) have been shown to be beneficial to cancer patients, but the mechanisms by which the extracts of two herbs elicit the beneficial effects are unclear. In this study, we have used human endometrial cancer cells to assess the anticancer efficacy of SB and FC on TGF-β signaling pathway components. SB and FC treatment of cancer cells resulted in a significant decrease in expression of TGF-β isoforms, TGF-β receptors, and SMADs. Both herbs effectively inhibited basal and TGF-β1-induced cancer cell proliferation and invasion, which was accompanied with abrogation of Snail, Slug, matrix metalloproteinases (MMPs), αvβ3 integrin, focal adhesion kinase (FAK), and p-FAK expression. An inhibitor of TGF-βRI blocked TGF-β1-induced cell invasion and significantly diminished antitumor effects of SB and FC. These results suggest that SB and FC block endometrial cancer growth by downregulating TGF-β/SMAD signaling pathway.

Cardioprotective effect of notoginsenoside R1 in a rabbit lung remote ischemic postconditioning model via activation of the TGF-β1/TAK1 signaling pathway

Pharmacological postconditioning using cardioprotective agents is able to reduce myocardial infarct size. Notoginsenoside R1 (NG-R1), a phytoestrogen isolated from Panax notoginseng saponins (PNS), is considered to have anti-oxidative and anti-apoptotic properties. However, its cardioprotective properties and underlying mechanisms remain largely unknown. The aim of the present study was to determine the cardioprotective and anti-apoptotic effects of NG-R1 in an ischemia-reperfusion (IR)-induced myocardial injury rabbit model. A total of 45 Japanese big-ear rabbits were equally randomized to three groups: Control group, remote ischemic postconditioning (RIP) group and NG-R1 intervention group. At the endpoint of the experiment, the animals were sacrificed to remove myocardial tissues for the detection of transforming growth factor (TGF)-β1-TGF-β activated kinase 1 (TAK1) pathway-related proteins by immunohistochemistry and western blot analysis, the activities of caspase-3, -8 and -9 in myocardial cells by fluorometric assay, and the apoptosis of myocardial cells by terminal deoxynucleotidyl-transferase-mediated dUTP nick end labeling. Right and left lung tissues were stained with hematoxylin and eosin (H&E) to observe the severity of injury. NG-R1 treatment reduced the activity of superoxide dismutase, increased the content of malondialdehyde, reduced the activities of caspase-3, -8 and -9, and inhibited the apoptosis of myocardial cells in rabbits undergoing RIP. In addition, the expression of TGF-β1-TAK1 signaling pathway-related proteins was downregulated following NG-R1 intervention. H&E staining of bilateral lung tissues showed that cell morphology was generally intact without significant alveolar congestion, and there was no significant difference among the three groups. These results indicate that NG-R1 protects the heart against IR injury, possibly by inhibiting the activation of the TGF-β1-TAK1 signaling pathway and attenuating apoptotic stress in the myocardium.

Absence of TNF-α enhances inflammatory response in the newborn lung undergoing mechanical ventilation

Bronchopulmonary dysplasia (BPD), characterized by impaired alveolarization and vascularization in association with lung inflammation and apoptosis, often occurs after mechanical ventilation with oxygen-rich gas (MV-O2). As heightened expression of the proinflammatory cytokine TNF-α has been described in infants with BPD, we hypothesized that absence of TNF-α would reduce pulmonary inflammation, and attenuate structural changes in newborn mice undergoing MV-O2 Neonatal TNF-α null (TNF-α(-/-)) and wild type (TNF-α(+/+)) mice received MV-O2 for 8 h; controls spontaneously breathed 40% O2 Histologic, mRNA, and protein analysis in vivo were complemented by in vitro studies subjecting primary pulmonary myofibroblasts to mechanical stretch. Finally, TNF-α level in tracheal aspirates from preterm infants were determined by ELISA. Although MV-O2 induced larger and fewer alveoli in both, TNF-α(-/-) and TNF-α(+/+) mice, it caused enhanced lung apoptosis (TUNEL, caspase-3/-6/-8), infiltration of macrophages and neutrophils, and proinflammatory mediator expression (IL-1β, CXCL-1, MCP-1) in TNF-α(-/-) mice. These differences were associated with increased pulmonary transforming growth factor-β (TGF-β) signaling, decreased TGF-β inhibitor SMAD-7 expression, and reduced pulmonary NF-κB activity in ventilated TNF-α(-/-) mice. Preterm infants who went on to develop BPD showed significantly lower TNF-α levels at birth. Our results suggest a critical balance between TNF-α and TGF-β signaling in the developing lung, and underscore the critical importance of these key pathways in the pathogenesis of BPD. Future treatment strategies need to weigh the potential benefits of inhibiting pathologic cytokine expression against the potential of altering key developmental pathways.

Loss of IκB kinase β promotes myofibroblast transformation and senescence through activation of the ROS-TGFβ autocrine loop

Using forward and reverse genetics and global gene expression analyses, we explored the crosstalk between the IκB kinase β (IKKβ) and the transforming growth factor β (TGFβ) signaling pathways. We show that in vitro ablation of Ikkβ in fibroblasts led to progressive ROS accumulation and TGFβ activation, and ultimately accelerated cell migration, fibroblast-myofibroblast transformation and senescence. Mechanistically, the basal IKKβ activity was required for anti-oxidant gene expression and redox homeostasis. Lacking this activity, IKKβ-null cells showed ROS accumulation and activation of stress-sensitive transcription factor AP-1/c-Jun. AP-1/c-Jun activation led to up-regulation of the Tgfβ2 promoter, which in turn further potentiated intracellular ROS through the induction of NADPH oxidase (NOX). These data suggest that by blocking the autocrine amplification of a ROS-TGFβ loop IKKβ plays a crucial role in the prevention of fibroblast-myofibroblast transformation and senescence.

HBx interacted with Smad4 to deprive activin a growth inhibition function in hepatocyte HL7702 on CRM1 manner

Hepatitis B virus (HBV) is implicated in the pathogenesis of hepatocellular carcinoma, which has been found to be associated with TGF-beta signaling. Activin A is a TGF-β family cytokine that exhibits cell proliferation inhibition on normal hepatocyte. How HBV-encoded X oncoprotein play in activin's activity on hepatocyte has not been developed. In this study, a nontumor hepatic cell line HL7702 with HBX ectogenic expression has been established. MTT and BrdU assays showed that HBx promoted growth of HL7702 cells in vitro and downregulated activin signaling. Deregulated activin signaling pathway by HBX failed to activate target gene p21/waf1 and p15 transcription. In addition, mammalian two-hybrid and coimmunoprecipitation assays revealed that HBX could directly interact with activin signaling transduction protein Smad4, making activated Smad2/3/4 nucleus translocation suppressed. Furthermore, we detected that leptomycin B, the inhibitor of CRM1 protein, could recover nuclear translocation of endogenous Smads complex in HL7702 with HBX expression, indicating that HBX antagonized Smads nucleus translocation, at least partially, on CRM1-dependent manner. Leptomycin B was found to have antigrowth activity on HBX-expressed HL7702, according to its antitumor function in previous study. Above all, HBX antagonized activin signaling in normal human liver cells by interacting with Smad4 might one of the considerable causes of HBX-induced hepatocyte transformation, which deprived activin's cell growth inhibition function at an early stage of tumorigenesis.

The emerging role of fibroblast growth factor 21 in diabetic nephropathy

Diabetic nephropathy (DN), an important cause of end-stage renal diseases, brings about great social and economic burden. Due to the variable pathological changes and clinical course, the prognosis of DN is very difficult to predict. DN is also usually associated with enhanced genomic damage and cellular injury. Fibroblast growth factor 21 (FGF21), a nutritionally regulated hormone secreted mainly by the liver, plays a critical role in metabolism. Administration of FGF21 decreases blood glucose, triglyceride, and cholesterol levels, and improves insulin sensitivity, which is closely associated with the development and progression of glomerular diseases. In addition, FGF21 level was associated with renal function. However, the precise role of FGF21 in DN remains unclear. This review will give a comprehensive understanding of the underlying role of FGF21 and its possible interaction with other molecules in DN.

TGF-β1 activates the canonical NF-κB signaling to promote cell survival and proliferation in dystrophic muscle fibroblasts in vitro

Activated fibroblasts continue to proliferate at injury sites, leading to progressive muscular fibrosis in Duchenne muscular dystrophy (DMD). TGF-β1 is a dominant profibrotic mediator thought to play a critical role in muscle fibrosis; however, the implicated mechanisms are not fully understood. Here we showed that TGF-β1 increased the resistance to apoptosis and stimulated cell cycle progression in dystrophic muscle fibroblasts under serum deprivation conditions in vitro. TGF-β1 treatment activated the canonical NF-κB pathway; and we found that pharmacological inhibition of IKKβ with IMD-0354 and RelA gene knockdown with siRNA attenuated these effects of TGF-β1 on dystrophic muscle fibroblasts. Collectively, our data suggest that TGF-β1 prevents apoptosis and cell cycle arrest in dystrophic muscle fibroblasts through the canonical NF-κB signaling pathway.

Proteomic Profiling of Radiation-Induced Skin Fibrosis in Rats: Targeting the Ubiquitin-Proteasome System

PURPOSE

To investigate the molecular changes underlying the pathogenesis of radiation-induced skin fibrosis.

METHODS AND MATERIALS

Rat skin was irradiated to 30 or 45 Gy with an electron beam. Protein expression in fibrotic rat skin and adjacent normal tissues was quantified by label-free protein quantitation. Human skin cells HaCaT and WS-1 were treated by x-ray irradiation, and the proteasome activity was determined with a fluorescent probe. The effect of proteasome inhibitors on Transforming growth factor Beta (TGF-B) signaling was measured by Western blot and immunofluorescence. The efficacy of bortezomib in wound healing of rat skin was assessed by the skin injury scale.

RESULTS

We found that irradiation induced epidermal and dermal hyperplasia in rat and human skin. One hundred ninety-six preferentially expressed and 80 unique proteins in the irradiated fibrotic skin were identified. Through bioinformatic analysis, the ubiquitin-proteasome pathway showed a significant fold change and was investigated in greater detail. In vitro experiments demonstrated that irradiation resulted in a decline in the activity of the proteasome in human skin cells. The proteasome inhibitor bortezomib suppressed profibrotic TGF-β downstream signaling but not TGF-β secretion stimulated by irradiation in HaCaT and WS-1 cells. Moreover, bortezomib ameliorated radiation-induced skin injury and attenuated epidermal hyperplasia.

CONCLUSION

Our findings illustrate the molecular changes during radiation-induced skin fibrosis and suggest that targeting the ubiquitin-proteasome system would be an effective countermeasure.

IKKβ acts as a tumor suppressor in cancer-associated fibroblasts during intestinal tumorigenesis

Pallangyo et al. report that fibroblast-specific IKKβ deletion in Col1a2Cre-ERT2 mice promotes AOM/DSS-induced intestinal tumorigenesis, suggesting a tumor suppressor role for this kinase. In contrast, a companion study by Koliaraki et al. based on IKKβ deletion in ColVI-expressing intestinal mesenchymal cells suggests a role for IKKβ in promoting intestinal tumorigenesis. The two studies raise the awareness that in the context of tumorigenesis, IKKβ/NF-κB may have distinct functions in different fibroblast subpopulations.

Cancer-associated fibroblasts (CAFs) comprise one of the most important cell types in the tumor microenvironment. A proinflammatory NF-κB gene signature in CAFs has been suggested to promote tumorigenesis in models of pancreatic and mammary skin cancer. Using an autochthonous model of colitis-associated cancer (CAC) and sporadic cancer, we now provide evidence for a tumor-suppressive function of IKKβ/NF-κB in CAFs. Fibroblast-restricted deletion of Ikkβ stimulates intestinal epithelial cell proliferation, suppresses tumor cell death, enhances accumulation of CD4⁺Foxp3⁺ regulatory T cells, and induces angiogenesis, ultimately promoting colonic tumor growth. In Ikkβ-deficient fibroblasts, transcription of negative regulators of TGFβ signaling, including Smad7 and Smurf1, is impaired, causing up-regulation of a TGFβ gene signature and elevated hepatocyte growth factor (HGF) secretion. Overexpression of Smad7 in Ikkβ-deficient fibroblasts prevents HGF secretion, and pharmacological inhibition of Met during the CAC model confirms that enhanced tumor promotion is dependent on HGF–Met signaling in mucosa of Ikkβ-mutant animals. Collectively, these results highlight an unexpected tumor suppressive function of IKKβ/NF-κB in CAFs linked to HGF release and raise potential concerns about the use of IKK inhibitors in colorectal cancer patients.

DMA(V) in Drinking Water Activated NF-κB Signal Pathway and Increased TGF-β and IL-1β Expressions in Bladder Epithelial Cells of Rats

Dimethylarsinic acid (DMA(V)) is the main product of arsenic methylation metabolism in vivo and is rat bladder carcinogen and tumor promoting agent. In this study, we measured the expressions of mRNA and proteins of NF-κB pathway members, IKKα, IKKβ, p65, and p50 in rat bladder epithelium by qRT-PCR and immunohistochemical analysis after rats received drinking water containing 100 and 200 ppm DMA(V) for 10 weeks. Transforming growth factor-β (TGF-β) immunoexpression in rat bladder epithelium and urine level of IL-1β also were determined. We found that DMA(V) dramatically increased the mRNA levels of NF-κB p50 and IKKα in the bladder epithelium of rats compared to the control group. Immunohistochemical examinations showed that DMA(V) increased immunoreactivities of IKKα, IKKβ, and phospho-NF-κB p50 in the cytoplasm and phospho-NF-κB p50 and p65 in nucleus of rat urothelial cells. In addition, DMA(V) treated rats exhibited significantly increased inflammatory factor TGF-β immunoreactivity in bladder epithelium and IL-1β secretion in urine. These data suggest that DMA(V) could activate NF-κB signal pathway and increase TGF-β and IL-1β expressions in bladder epithelial cells of rats.

Elevated TAK1 augments tumor growth and metastatic capacities of ovarian cancer cells through activation of NF-κB signaling

Transforming growth factor (TGF)-β-activating kinase 1 (TAK1) is a serine/threonine kinase which is frequently associated with human cancer progression. However, its functional role in tumorigenesis is still controversial. Here, we report that TAK1 enhances the oncogenic capacity of ovarian cancer cells through the activation of NF-κB signaling. We found that TAK1 is frequently upregulated and significantly associated with high-grade and metastatic ovarian cancers. Mechanistic studies showed that Ser412 phosphorylation is required for TAK1 in activating NF-κB signaling and promotes aggressiveness of ovarian cancer cells. Conversely, suppression of TAK1 activity by point mutation at Ser412, RNAi mediated gene knockdown or TAK1 specific inhibitor ((5Z) -7-Oxozeaenol) remarkably impairs tumor growth and metastasis in ovarian cancer in vitro and in vivo. Our study underscores the importance of targeting TAK1 as a promising therapeutic approach to counteract the ovarian cancer progression.