Multiple roles of mothers against decapentaplegic homolog 4 in tumorigenesis, stem cells, drug resistance, and cancer therapy

The transforming growth factor(TGF)-βsignaling pathway controls many cellular processes,including proliferation,differentiation,and apoptosis.Abnormalities in the TGF-βsignaling pathway and its components are closely related to the occurrence of many human diseases,including cancer.Mothers against decapentaplegic homolog 4(Smad4),also known as deleted in pancreatic cancer locus 4,is a typical tumor suppressor candidate gene locating at q21.1 of human chromosome 18 and the common mediator of the TGF-β/Smad and bone morphogenetic protein/Smad signaling pathways.It is believed that Smad4 inactivation correlates with the development of tumors and stem cell fate decisions.Smad4 also interacts with cytokines,miRNAs,and other signaling pathways,jointly regulating cell behavior.However,the regulatory function of Smad4 in tumorigenesis,stem cells,and drug resistance is currently controversial.In addition,Smad4 represents an attractive therapeutic target for cancer.Elucidating the specific role of Smad4 is important for understanding the mechanism of tumorigenesis and cancer treatment.Here,we review the identification and characterization of Smad4,the canonical TGF-β/Smad pathway,as well as the multiple roles of Smad4 in tumorigenesis,stem cells,and drug resistance.Furthermore,we provide novel insights into the prospects of Smad4-targeted cancer therapy and the challenges that it will face in the future.

Possible mechanisms associated with immune escape and apoptosis on anti-hepatocellular carcinoma effect of Mu Ji Fang granules

BACKGROUND Hepatocellular carcinoma(HCC)is one of the most common digestive system cancers with high mortality rates worldwide.The main ingredients in Mu Ji Fang Granules(MJF)are alkaloids,flavonoids,and polysaccharides.MJF has been used in the clinical treatment of hepatitis,cirrhosis and HCC for more than 30 years.Few previous studies have focused on the mechanism of MJF on tumor immunology in the treatment of HCC.AIM To explore the mechanism of action of MJF on tumor immunology in the treatment of HCC.METHODS The absorbable ingredients of MJF were identified using Molecule Network related to High Performance Liquid Chromatography-Electron Spray Ionization-Time of Flight-Mass Spectrometry,and hub potential anti-HCC targets were screened using network pharmacology and pathway enrichment analysis.Forty male mice were randomly divided into the Blank,Model,and MJF groups(1.8,5.4,and 10.8 g/kg/d)following 7 d of oral administration.Average body weight gain,spleen and thymus indices were calculated,tumor tissues were stained with hematoxylin and eosin,and Interferon gamma(IFN-γ),Tumor necrosis factorα(TNF-α),Interleukin-2,aspartate aminotransferase,alanine aminotransferase,alpha-fetoprotein(AFP),Fas,and FasL were measured by Enzyme-linked Immunosorbent Assay.Relevant mRNA expression of Bax and Bcl2 was evaluated by Real Time Quantitative PCR(RTqPCR)and protein expression of Transforming growth factorβ1(TGF-β1)and Mothers against decapentaplegic homolog(SMAD)4 was assessed by Western blotting.The HepG2 cell line was treated with 10 mg/mL,20 mg/mL,30 mg/mL,40 mg/mL of MJF,and another 3 groups were treated with TGF-β1 inhibitor(LY364947)and different doses of MJF.Relevant mRNA expression of TNF-α,IFN-γ,Bax and Bcl2 was evaluated by RT-qPCR and protein expression of TGF-β1,SMAD2,p-SMAD2,SMAD4,and SMAD7 was assessed by Western blotting.RESULTS It was shown that MJF improved body weight gain and tumor inhibition rate in H22 tumorbearing mice,protected immune organs and liver function,reduced the HCC indicator AFP,affected immunity and apoptosis,and up-regulated the TGF-β1/SMAD signaling pathway,by increasing the relative expression of TGF-β1,SMAD2,p-SMAD2 and SMAD4 and decreasing SMAD7,reducing immune factors TNF-αand IFN-γ,decreasing apoptosis cytokines Fas,FasL and Bcl2/Bax,and inhibiting the effect of LY364947 in HepG2 cells.CONCLUSION MJF inhibits HCC by activating the TGF-β1/SMAD signaling pathway,and affecting immune and apoptotic cytokines,which may be due to MJF adjusting immune escape and apoptosis.

Metabolic derivatives of alcohol and the molecular culpritsof fibro-hepatocarcinogenesis:Allies or enemies?

Chronic intake of alcohol undoubtedly overwhelms the structural and functional capacity of the liver by initiating complex pathological events characterized by steatosis,steatohepatitis,hepatic fibrosis and cirrhosis.Subsequently,these initial pathological events are sustained and ushered into a more complex and progressive liver disease,increasing the risk of fibrohepatocarcinogenesis.These coordinated pathological events mainly result from buildup of toxic metabolic derivatives of alcohol including but not limited to acetaldehyde(AA),malondialdehyde(MDA),CYP2E1-generated reactive oxygen species,alcohol-induced gut-derived lipopolysaccharide,AA/MDA protein and DNA adducts.The metabolic derivatives of alcohol together with other comorbidity factors,including hepatitis B and C viral infections,dysregulated iron metabolism,abuse of antibiotics,schistosomiasis,toxic drug metabolites,autoimmune disease and other non-specific factors,have been shown to underlie liver diseases.In view of the multiple etiology of liver diseases,attempts to delineate the mechanism by which each etiological factor causes liver disease has always proved cumbersome if not impossible.In the case of alcoholic liver disease(ALD),it is even more cumbersome and complicated as a result of the many toxic metabolic derivatives of alcohol with their varying liver-specific toxicities.In spite of all these hurdles,researchers and experts in hepatology have strived to expand knowledge and scientific discourse,particularly on ALD and its associated complications through the medium of scientific research,reviews and commentaries.Nonetheless,the molecularmechanisms underpinning ALD,particularly those underlying toxic effects of metabolic derivatives of alcohol on parenchymal and non-parenchymal hepatic cells leading to increased risk of alcohol-induced fibrohepatocarcinogenesis,are still incompletely elucidated.In this review,we examined published scientific findings on how alcohol and its metabolic derivatives mount cellular attack on each hepatic cell and the underlying molecular mechanisms leading to disruption of core hepatic homeostatic functions which probably set the stage for the initiation and progression of ALD to fibro-hepatocarcinogenesis.We also brought to sharp focus,the complex and integrative role of transforming growth factor beta/small mothers against decapentaplegic/plasminogen activator inhibitor-1 and the mitogen activated protein kinase signaling nexus as well as their cross-signaling with toll-like receptormediated gut-dependent signaling pathways implicated in ALD and fibro-hepatocarcinogenesis.Looking into the future,it is hoped that these deliberations may stimulate new research directions on this topic and shape not only therapeutic approaches but also models for studying ALD and fibro-hepatocarcinogenesis.

Genetic variations in the SMAD4 gene and gastric cancer susceptibility

AIM:To explore the association between mothers against decapentaplegic homolog 4 (SMAD4) gene polymorphisms and gastric cancer risk.METHODS:Five tagging single nucleotide polymor-phisms (tSNPs) in the SMAD4 gene were selected and genotyped in 322 gastric cancer cases and 351 cancerfree controls in a Chinese population by using the polymerase chain reactionrestriction fragment length polymorphism method.Immunohistochemistry was used to examine SMAD4 protein expression in 10 normal gastric tissues adjacent to tumors.RESULTS:In the single-locus analysis,two significantly decreased risk polymorphisms for gastric cancer were observed:the SNP3 rs17663887 TC genotype (adjusted odds ratio=0.38,95% confidence interval:0.21-0.71),compared with the wild-type TT genotype and the SNP5 rs12456284 GG genotype (0.31,0.16-0.60),and with the wild-type AA genotype.In the combined analyses of these two tSNPs,the combined genotypes with 2-3 protective alleles (SNP3 C and SNP5 G allele) had a significantly decreased risk of gastric cancer (0.28,0.16-0.49) than those with 0-1 protective allele.Furthermore,individuals with 0-1 protective allele had significantly decreased SMAD4 protein expression levels in the norma tissues adjacent to tumors than those with 2-3 protective alleles (P=0.025).CONCLUSION:These results suggest that genetic variants in the SMAD4 gene play a protective role in gastric cancer in a Chinese population.

Increased presence of effector lymphocytes during Helicobacter hepaticus-induced colitis

AIM： To identify and characterize drosophila mothers against decapentaplegic （SMAD）3-dependent changes in immune cell populations following infection with He- Iicobacter hepaticus （H. hepaticus）. METHODS： SMAD3/ （n = L9） and colitis-resistant SMAD3＋/ （n = 24） mice （8-10 wk of age） were in- fected with/-/, hepaticus and changes in immune cell populations [T lymphocytes, natural killer （NK） cells, T regulatory cells] were measured in the spleen and mesenteric lymph nodes （MsLNs） at 0 d, 3 d, 7 d and 28 d post-infection using flow cytometry. Genotype-dependent changes in T lymphocytes and granzyme B＋ cells were also assessed after 28 d in proximal colon tissue using immunohistochemistry. RESULTS： As previously observed, SMAD3＋, but not SMAD3＋/- mice, developed colitis, peaking at 4 wk post-infection. No significant changes in T cell subsets were observed in the spleen or in the MsLNs between genotypes at any time point. However, CD4＋ and CD8＋/ CD62L＋＋ cells, an effector T lymphocyte population, as well as NK cells （NKp46/DX5＋） were significantly higher in the MsLNs of SMAD3/ mice at 7 d and 28 d post-in- fection. In the colon, a higher number of CD3＋ cells were present in SMAD3＋ compared to SMAD3＋/- mice at base- line, which did not significantly change during infection. However, the number of granzyme B＋ cells, a marker of cytolytic lymphoo/tes, significantly increased in SMAD3＋ mice 28 d post-infection compared to both SMAD3＋/- mice and to baseline values. This was consistent with more severe colitis development in these animals. CONCLUSION： Data suggest that defects in SMAD3 signaling increase susceptibility to H. hepaticus-induced colitis through aberrant activation and/or dysregulation of effector lymphoo/tes.

Regulation of transforming growth factor-β signaling as a therapeutic approach to treating colorectal cancer

According to data from 2020,Slovakia has long been among the top five countries with the highest incidence rate of colorectal cancer(CRC)worldwide,and the rate is continuing to rise every year.In approximately 80%of CRC cases,allelic loss(loss of heterozygosity,LOH)occurs in the long arm of chromosome 18q.The most important genes that can be silenced by 18q LOH or mutations are small mothers against decapentaplegic homolog(SMAD)2 and SMAD4,which are intracellular mediators of transforming growth factor(TGF)-βsuperfamily signals.TGF-βplays an important role in the pro-oncogenic processes,including such properties as invasion,epithelial-mesenchymal transition(commonly known as EMT),promotion of angiogenesis,and immunomodulatory effects.Several recent studies have reported that activation of TGF-βsignaling is related to drug resistance in CRC.Because the mechanisms of drug resistance are different between patients in different stages of CRC,personalized treatment is more effective.Therefore,knowledge of the activation and inhibition of factors that affect the TGF-βsignaling pathway is very important.

Hsa_circRNA_102610 upregulation in Crohn’s disease promotes transforming growth factor-β1-induced epithelial-mesenchymal transition via sponging of hsa-miR-130a-3p

BACKGROUND The incidence of inflammatory bowel disease,a chronic intestinal inflammatory disorder that includes Crohn’s disease(CD)and ulcerative colitis,is rising.Circular RNAs are considered valuable diagnostic biomarkers for CD.Current evidence supports the views that epithelial-mesenchymal transition(EMT)plays an important role in CD pathogenesis,and that hsa-miR-130a-3p can inhibit transforming growth factor-β1(TGF-β1)-induced EMT.Our previous study revealed that hsa_circRNA_102610 was upregulated in CD patients.Moreover,we predicted an interaction between hsa_circRNA_102610 and hsa-miR-130a-3p.Thus,we hypothesized that hsa_circRNA_102610 may play roles in the proliferation and EMT of intestinal epithelial cells by sponging hsa-miR-130a-3p to participate in the pathogenesis of CD.AIM To explore the mechanism of hsa_circRNA_102610 in the pathogenesis of CD.METHODS The relative expression levels of hsa_circRNA_102610 and hsa-miR-130a-3p in patients were detected by quantitative reverse transcription-polymerase chain reaction.The proliferation of human intestinal epithelial cells(HIECs)and normal-derived colon mucosa cell line 460(NCM460)cells was detected by cell counting kit-8,5-ethynyl-2’-deoxyuridine staining and cell cycle assays following overexpression or downregulation of hsa_circRNA_102610.Cell proliferation assays were performed as described above in a rescue experiment with hsa-miR-130a-3p mimics.The interaction of hsa_circRNA_102610 and hsa-miR-130a-3p was verified by fluorescence in situ hybridization and dual luciferase reporter assays.The relative expression levels of CyclinD1,mothers against decapentaplegic homolog 4(SMAD4),E-cadherin,N-cadherin and Vimentin were detected by western blotting following hsa_circRNA_102610 overexpression,TGF-β1-induced EMT or hsa-miR-130a-3p mimic transfection(in rescue experiments).RESULTS Upregulation of hsa_circRNA_102610 was determined to be positively correlated with elevated fecal calprotectin levels in CD(r=0.359,P=0.007)by Pearson correlation analysis.Hsa_circRNA_102610 promoted the proliferation of HIECs and NCM460 cells,while hsa-miR-130a-3p reversed the cell proliferationpromoting effects of hsa_circRNA_102610.Fluorescence in situ hybridization and dual luciferase reporter assays showed that hsa_circRNA_102610 directly bound hsa-miR-130a-3p in NCM460 and 293T cells.An inverse correlation between downregulation of hsa-miR-130a-3p and upregulation of hsa_circRNA_102610 in CD patients was observed(r=-0.290,P=0.024)by Pearson correlation analysis.Moreover,overexpression of hsa_circRNA_102610 promoted SMAD4 and CyclinD1 protein expression validated by western-blotting.Furthermore,overexpression of hsa_circRNA_102610 promoted TGF-β1 induced EMT in HIECs and NCM460 cells via targeting of hsa-miR-130a-3p,with increased expression of Vimentin and N-cadherin and decreased expression of E-cadherin.CONCLUSION Hsa_circRNA_102610 upregulation in CD patients could promote the proliferation and EMT of intestinal epithelial cells via sponging of hsa-miR-130a-3p.

Exosomal let-7a-5p derived from human umbilical cord mesenchymal stem cells alleviates coxsackievirus B3-induced cardiomyocyte ferroptosis via the SMAD2/ZFP36 signal axis

Viral myocarditis(VMC)is one of the most common acquired heart diseases in children and teenagers.However,its pathogenesis is still unclear,and effective treatments are lacking.This study aimed to investigate the regulatory pathway by which exosomes alleviate ferroptosis in cardiomyocytes(CMCs)induced by coxsackievirus B3(CVB3).CVB3 was utilized for inducing the VMC mouse model and cellular model.Cardiac echocardiography,left ventricular ejection fraction(LVEF),and left ventricular fractional shortening(LVFS)were implemented to assess the cardiac function.In CVB3-induced VMC mice,cardiac insufficiency was observed,as well as the altered levels of ferroptosis-related indicators(glutathione) peroxidase 4(GPX4),glutathione(GSH),and malondialdehyde(MDA).However,exosomes derived from human umbilical cord mesenchymal stem cells(hucMSCs-exo)could restore the changes caused by CVB3 stimulation.Let-7a-5p was enriched in hucMSCs-exo,and the inhibitory ffect of hucMSCs-exoa-ie-pmimo on CVB3-induced ferroptosis was higher than that of hucMSCs-exommie N(NC:negative control).Mothers against decapentaplegic homolog 2(SMAD2)increased in the VMC group,while the expression of zinc-finger protein 36(ZFP36)decreased.Let-7a-5p was confirmed to interact with SMAD2 messenger RNA(mRNA),and the SMAD2 protein interacted directly with the ZFP36 protein.Silencing SMAD2 and overexpressing ZFP36 inhibited the expression of ferroptosis-related indicators.Meanwhile,the levels of GPX4,solute carrier family 7,member 11(SLC7A11),and GSH were lower in the SMAD2 overexpression plasmid(oe-SMAD2)+let-7a-5p mimic group than in the oe-NC+let-7a-5p mimic group,while those of MDA,reactive oxygen species(ROS),and Fe^(2+)increased.In conclusion,these data showed that ferroptosis could be regulated by mediating SMAD2 expression.Exo-let-7a-5p derived from hucMSCs could mediate SMAD2 to promote the expression of ZFP36,which further inhibited the ferroptosis of CMCs to alleviate CVB3-induced VMC.

TGF-β_(1)/Smad信号通路与肾间质纤维化

肾间质纤维化(renal interstitial fibrosis,RIF)是慢性肾脏病(chronic kidney disease,CKD)的主要病理学基础,是CKD进展至终末期肾病的最终共同途径,与肾脏疾病的预后密切相关。RIF是多种信号通路相互作用的结果,其中转化生长因子(transforming growth factor,TGF)-β_(1)/small mothers against decapentaplegic(Smad)是RIF的主要信号转导通路,机体受到外来刺激后促进TGF-β_(1)与其受体结合并激活下游Smad蛋白参与RIF进程。TGF-β_(1)是RIF的中心介质并在所有类型肾脏细胞中广泛表达。Smad蛋白是目前已知的唯一的TGF-β受体的胞内基底酶物,其中,Smad3和Smad7失衡导致成纤维细胞激活和细胞外基质大量沉积是RIF进展的关键机制。TGF-β_(1)/Smad信号通路还可通过调控非编码RNA参与RIF进程。因此,靶向抑制TGF-β_(1)/Smad信号通路可作为RIF的潜在治疗策略。文章综述了TGF-β_(1)/Smad信号通路在RIF中的作用及通过阻断TGF-β_(1)并选择性抑制Smad信号传导治疗RIF的潜力,以期为临床诊疗RIF提供启发。

Effect of SMAD7 gene overexpression on TGF-β1-induced profibrotic responses in fibroblasts derived from Peyronie＇s plaque

Transforming growth factor-β1 （TGF-β1） has been identified as one of the most important fibrogenic cytokines associated with Peyronie＇s disease （PD）. The mothers against decapentaplegic homolog 7 （SMAD7） is an inhibitory Smad protein that blocks TGF-J3 signaling pathway. The aim of this study was to examine the anti-fibrotic effect of the SMAD7 gene in primary fibroblasts derived from human PD plaques. PD fibroblasts were pretreated with the SMAD7 gene and then stimulated with TGF-β1. Treated fibroblasts were used for Western blotting, fluorescent immunocytochemistry, hydroxyproline determination, and terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling assays. Overexpression of the SMAD7 gene inhibited TGF-β1-induced phosphorylation and nuclear translocation of SMAD2 and SMAD3, transdifferentiation of fibroblasts into myofibroblasts, and quashed TGF-β1-induced production of extracellular matrix protein and hydroxyproline. Overexpression of the SMAD7 gene decreased the expression of cyclin D1 （a positive cell cycle regulator） and induced the expression of poly （ADP-ribose） polymerase 1, which is known to terminate Smad-mediated transcription, in PD fibroblasts. These findings suggest that the blocking of the TGF-β pathway by use of SMAD7 may be a promising therapeutic strategy for the treatment of PD.

San-Cao Granule (三草颗粒) Ameliorates Hepatic Fibrosis through High Mobility Group Box-1 Protein/Smad Signaling Pathway

Objective： To investigate the possible mechanism of San-Cao Granule（SCG, 三草颗粒） mediating antiliver fibrosis. Methods： A total of 60 male Sprague-Dawley rats were randomly divided into the normal control group, porcine serum-treated group, ursodesoxycholic acid（UDCA, 60 mg/kg）, SCG（3.6 g/kg） group, SCG（1.8 g/kg） group and SCG（0.9 g/kg） group, with 10 rats in each group. Liver fibrosis was induced with porcine serum by intraperitoneal injection for 8 weeks, except for the normal control group. Then, the rats in the three SCG-treated groups and UDCA group were administered SCG and UDCA respectively for 4 weeks. The serum levels of alanine transaminase（ALT）, aspartate transaminase（AST）, albumin（ALB）, total bilirubin（TBIL）, hyaluronic acid（HA）, laminin（LN）, and type Ⅳcollagen（ⅣC） were examined using commercial kits and hepatic histopathology was examined with hematoxylin and eosin and Masson staining. Moreover, the protein expression levels of high mobility group box-1 protein（HMGB1）, transforming growth factor β1（TGF-β1）, phosphorylated mothers against decapentaplegic homolog 3（p-Smad3）, Smad7, toll-like receptor 4（TLR4）, myeloid differentiation factor 88（My D88）, nuclear factor-kappa B（NF-κB） and α-smooth muscle actin（α-SMA） were determined by western blot, immunohistochemistry and real time quantitativereverse transcription polymerase. Results： Both SCG（3.6 and 1.8 g/kg） and UDCA significantly ameliorated the liver fibrosis induced by porcine serum as indicated by retarding the serum levels increasing of ALT, AST, TBIL, HA, LN and ⅣC and preventing the serum level reducing of ALB compared with the model group（all P〈0.01）. Meanwhile, the collagen deposition was attenuated by SCG and UDCA treatment. Furthermore, SCG markedly reduced the expressions of HMGB1, TGF-β1, p-Smad3, TLR4, My D88, NF-κB and α-SMA, and enhanced the expression of the Smad7 compared with the model group（all P〈0.01）. Conclusion： SCG ameliorates hepatic fibrosis possibly through inhibiting HMGB1, TLR4/NF-κB and TGF-β1/Smad signaling pathway.

LncRNA-m18as1 competitively binds with miR-18a-5p to regulate follicle-stimulating hormone secretion through the Smad2/3 pathway in rat primary pituitary cells

Long noncoding RNAs(lncRNAs)are expressed in different species and different tissues,and perform different functions,but little is known about their involvement in the synthesis or secretion of follicle-stimulating hormone(FSH).In general,we have revealed lnc RNA-micro RNA(mi RNA)-messenger RNA(m RNA)interactions that may play important roles in rat primary pituitary cells.In this study,a new lncRNA was identified for the first time.First,we analyzed the gene expression of lncRNA-m18as1 in different tissues and different stages by reverse transcription-quantitative polymerase chain reaction(RT-qPCR)and observed the localization of lncRNA-m18as1 with fluorescence in situ hybridization,which indicated that this lncRNA was distributed mainly in the cytoplasm.Next,we used RT-qPCR and enzyme-linked immunosorbent assay(ELISA)to analyze the regulation of FSH synthesis and secretion after overexpression or knockdown of lncRNA-m18as1 and found that lncRNA-m18as1 was positively correlated with FSH synthesis and secretion.In addition,mothers against decapentaplegic homolog 2(Smad2)was highly expressed in our sequencing results.We also screened miR-18a-5p from our sequencing results as a miRNA that may bind to lncRNA-m18as1 and Smad2.We used RNA immunoprecipitation-qPCR(RIP-qPCR)and/or dual luciferase assays to confirm that lncRNA-m18as1 interacted with miR-18a-5p and miR-18a-5p interacted with Smad2.Fluorescence in situ hybridization(FISH)showed that lncRNA-m18as1 and miR-18a-5p were localized mainly in the cytoplasm.Finally,we determined the relationship among lncRNA-m18as1,miR-18a-5p,and the Smad2/3 pathway.Overall,we found that lncRNA-m18as1 acts as a molecular sponge of miR-18a-5p to regulate the synthesis and secretion of FSH through the Smad2/3 pathway.