MiR-92d-3p suppresses the progression of diabetic nephropathy renal fibrosis by inhibiting the C3/HMGB1/TGF-β1 pathway

The pathogenesis of diabetic nephropathy (DN) has not been fully elucidated. MicroRNAs (miRNAs) play an important role in the onset and development of DN renal fibrosis. Thus, the present study aimed to investigate the effect of miR-92d-3p on the progression of DN renal fibrosis. We used qRT-PCR to detect the expression levels of miR-92d-3p in the kidneys of patients with DN. Then, after transfecting lentiviruses containing miR-92d-3p into the kidneys of a DN mouse model and HK-2 cell line, we used qRT-PCR to detect the expression levels of miR-92d-3p, C3, HMGB1, TGF-β1, α-SMA, E-cadherin, and Col I. The expression levels of interleukin (IL) 1β (IL-1β), IL-6, and tumor necrosis factor-α (TNF-α) in the HK-2 cells were detected through enzyme-linked immunosorbent assay (ELISA), and Western blotting and immunofluorescence were used in detecting the expression levels of fibronectin, α-SMA, E-cadherin, and vimentin. Results showed that the expression levels of miR-92d-3p in the kidney tissues of patients with DN and DN animal model mice decreased, and C3 stimulated HK-2 cells to produce inflammatory cytokines. The C3/HMGB1/TGF-β1 pathway was activated, and epithelial-to-interstitial transition (EMT) was induced in the HK-2 cells after human recombinant C3 and TGF-β1 protein were added. miR-92d-3p inhibited inflammatory factor production by C3 in the HK-2 cells and the activation of the C3/HMGB1/TGF-β1 pathway and EMT by C3 and TGF-β1. miR-92d-3p suppressed the progression of DN renal fibrosis by inhibiting the activation of the C3/HMGB1/TGF-β1 pathway and EMT.     

MicroRNA-10 Family Promotes the Epithelial-to-Mesenchymal Transition in Renal Fibrosis by the PTEN/Akt Pathway

Renal fibrosis (RF) is a common reason for renal failure, and epithelial-mesenchymal transition (EMT) is a vital mechanism that promotes the development of RF. It is known that microRNA-10 (miR-10) plays an important role in cancer EMT; however, whether it takes part in the EMT process of RF remains unclear. Therefore, we established an in vivo model of unilateral ureteral obstruction (UUO), and an in vitro model using TGF-β1, to investigate whether and how miR-10a and miR-10b take part in the EMT of RF. In addition, the combinatorial effects of miR-10a and miR-10b were assessed. We discovered that miR-10a and miR-10b are overexpressed in UUO mice, and miR-10a, miR-10b, and miRs-10a/10b knockout attenuated RF and EMT in UUO-treated mouse kidneys. Moreover, miR-10a and miR-10b overexpression combinatorially promoted RF and EMT in TGF-β1-treated HK-2 cells. Inhibiting miR-10a and miR-10b attenuated RF and EMT induced by TGF-β1. Mechanistically, miR-10a and miR-10b suppressed PTEN expression by binding to its mRNA3′-UTR and promoting the Akt pathway. Moreover, PTEN overexpression reduced miR-10a and miR-10b effects on Akt phosphorylation (p-Akt), RF, and EMT in HK-2 cells treated with TGF-β1. Taken together, miR-10a and miR-10b act combinatorially to negatively regulate PTEN, thereby activating the Akt pathway and promoting the EMT process, which exacerbates RF progression.     

MicroRNA-155 is regulated by the transforming growth factor beta/Smad pathway and contributes to epithelial cell plasticity by targeting RhoA

Transforming growth factor β (TGF-β) signaling facilitates metastasis in advanced malignancy. While a number of protein-encoding genes are known to be involved in this process, information on the role of microRNAs (miRNAs) in TGF-β-induced cell migration and invasion is still limited. By hybridizing a 515-miRNA oligonucleotide-based microarray library, a total of 28 miRNAs were found to be significantly deregulated in TGF-β-treated normal murine mammary gland (NMuMG) epithelial cells but not Smad4 knockdown NMuMG cells. Among upregulated miRNAs, miR-155 was the most significantly elevated miRNA. TGF-β induces miR-155 expression and promoter activity through Smad4. The knockdown of miR-155 suppressed TGF-β-induced epithelial-mesenchymal transition (EMT) and tight junction dissolution, as well as cell migration and invasion. Further, the ectopic expression of miR-155 reduced RhoA protein and disrupted tight junction formation. Reintroducing RhoA cDNA without the 3′ untranslated region largely reversed the phenotype induced by miR-155 and TGF-β. In addition, elevated levels of miR-155 were frequently detected in invasive breast cancer tissues. These data suggest that miR-155 may play an important role in TGF-β-induced EMT and cell migration and invasion by targeting RhoA and indicate that it is a potential therapeutic target for breast cancer intervention.     

miR-21 and miR-31 Converge on TIAM1 to Regulate Migration and Invasion of Colon Carcinoma Cells

TGF-β promotes cell migration and invasion, an attribute that is linked to the pro-metastasis function of this cytokine in late stage cancers. The LIM 1863 colon carcinoma organoid undergoes epithelial-mesenchymal transition (EMT) in response to TGF-β. This process is markedly accelerated by TNF-α, and we found that the levels of miR-21 and miR-31 were prominently elevated under the synergistic actions of TGF-β/TNF-α. Consistent with this, overexpression of either miR-21 or miR-31 significantly enhanced the effect of TGF-β alone on LIM 1863 morphological changes. More importantly, transwell assays demonstrated the positive effects of both miR-21 and miR-31 in TGF-β regulation of LIM 1863 motility and invasiveness. Elevated levels of miR-21 and miR-31 also enhanced motility and invasiveness of other colon carcinoma cell lines. We present compelling evidence that TIAM1, a guanidine exchange factor of the Rac GTPase, is a direct target of both miR-21 and miR-31. Indeed in LIM 1863 cells, suppression of TIAM1 is required for miR-21/miR-31 to enhance cell migration and invasion. Therefore, we have uncovered miR-21 and miR-31 as downstream effectors of TGF-β in facilitating invasion and metastasis of colon carcinoma cells.     

Naringenin Decreases Invasiveness and Metastasis by Inhibiting TGF-β-Induced Epithelial to Mesenchymal Transition in Pancreatic Cancer Cells

Epithelial to mesenchymal transition (EMT) promotes cellular motility, invasiveness and metastasis during embryonic development and tumorigenesis. Transforming growth factor-β (TGF-β) signaling pathway is a key regulator of EMT. A lot of evidences suggest that this process is Smad3-dependent. Herein we showed that exposure of aspc-1 and panc-1 pancreatic cancer cells to TGF-β1 resulted in characteristic morphological alterations of EMT, and enhancement of cell motility and gemcitabine (Gem) resistance along with an up-regulation of EMT markers genes such as vimentin, N-cadherin, MMP2 and MMP9. Naringenin (Nar) down-regulated EMT markers expression in both mRNA and protein levels by inhibiting TGF-β1/Smad3 signal pathway in the pancreatic cancer cells. Consequently, Nar suppressed the cells migration and invasion and reversed their resistance to Gem.     

Low-Dose Paclitaxel Ameliorates Pulmonary Fibrosis by Suppressing TGF-β1/Smad3 Pathway via miR-140 Upregulation

Abnormal TGF-β1/Smad3 activation plays an important role in the pathogenesis of pulmonary fibrosis, which can be prevented by paclitaxel (PTX). This study aimed to investigate an antifibrotic effect of the low-dose PTX (10 to 50 nM in vitro, and 0.6 mg/kg in vivo). PTX treatment resulted in phenotype reversion of epithelial-mesenchymal transition (EMT) in alveolar epithelial cells (AECs) with increase of miR-140. PTX resulted in an amelioration of bleomycin (BLM)-induced pulmonary fibrosis in rats with reduction of the wet lung weight to body weight ratios and the collagen deposition. Our results further demonstrated that PTX inhibited the effect of TGF-β1 on regulating the expression of Smad3 and phosphorylated Smad3 (p-Smad3), and restored the levels of E-cadherin, vimentin and α-SMA. Moreover, lower miR-140 levels were found in idiopathic pulmonary fibrosis (IPF) patients, TGF-β1-treated AECs and BLM-instilled rat lungs. Through decreasing Smad3/p-Smad3 expression and upregulating miR-140, PTX treatment could significantly reverse the EMT of AECs and prevent pulmonary fibrosis of rats. The action of PTX to ameliorate TGF-β1-induced EMT was promoted by miR-140, which increased E-cadherin levels and reduced the expression of vimentin, Smad3 and p-Smad3. Collectively, our results demonstrate that low-dose PTX prevents pulmonary fibrosis by suppressing the TGF-β1/Smad3 pathway via upregulating miR-140.     

MiR-487a Promotes TGF-β1-induced EMT,the Migration and Invasion of Breast Cancer Cells by Directly Targeting MAGI2

Tumor metastasis is a complex and multistep process and its exact molecular mechanisms remain unclear. We attempted to find novel microRNAs (miRNAs) contributing to the migration and invasion of breast cancer cells. In this study, we found that the expression of miR-487a was higher in MDA-MB-231breast cancer cells with high metastasis ability than MCF-7 breast cancer cells with low metastasis ability and the treatment with transforming growth factor β1 (TGF-β1) significantly increased the expression of miR-487a in MCF-7 and MDA-MB-231 breast cancer cells. Subsequently, we found that the transfection of miR-487a inhibitor significantly decreased the expression of vimentin, a mesenchymal marker, while increased the expression of E-cadherin, an epithelial marker, in both MCF-7 cells and MDA-MB-231 cells. Also, the inactivation of miR-487a inhibited the migration and invasion of breast cancer cells. Furthermore, our findings demonstrated that miR-487a directly targeted the MAGI2 involved in the stability of PTEN. The down-regulation of miR-487a increased the expression of p-PTEN and PTEN, and reduced the expression of p-AKT in both cell lines. In addition, the results showed that NF-kappaB (p65) significantly increased the miR-487a promoter activity and expression, and TGF-β1 induced the increased miR-487a promoter activity via p65 in MCF-7 cells and MDA-MB-231 cells. Moreover, we further confirmed the expression of miR-487a was positively correlated with the lymph nodes metastasis and negatively correlated with the expression of MAGI2 in human breast cancer tissues. Overall, our results suggested that miR-487a could promote the TGF-β1-induced EMT, the migration and invasion of breast cancer cells by directly targeting MAGI2.     

An Integrated Expression Profiling Reveals Target Genes of TGF-β and TNF-α Possibly Mediated by MicroRNAs in Lung Cancer Cells

EMT (epithelial-mesenchymal transition) is crucial for cancer cells to acquire invasive phenotypes. In A549 lung adenocarcinoma cells, TGF-β elicited EMT in Smad-dependent manner and TNF-α accelerated this process, as confirmed by cell morphology, expression of EMT markers, capacity of gelatin lysis and cell invasion. TNF-α stimulated the phosphorylation of Smad2 linker region, and this effect was attenuated by inhibiting MEK or JNK pathway. Comprehensive expression analysis unraveled genes differentially regulated by TGF-β and TNF-α, such as cytokines, chemokines, growth factors and ECM (extracellular matrices), suggesting the drastic change in autocrine/paracrine signals as well as cell-to-ECM interactions. Integrated analysis of microRNA signature enabled us to identify a subset of genes, potentially regulated by microRNAs. Among them, we confirmed TGF-β-mediated induction of miR-23a in lung epithelial cell lines, target genes of which were further identified by gene expression profiling. Combined with in silico approaches, we determined HMGN2 as a downstream target of miR-23a. These findings provide a line of evidence that the effects of TGF-β and TNF-α were partially mediated by microRNAs, and shed light on the complexity of molecular events elicited by TGF-β and TNF-α.     

MTHFD2 promotes tumorigenesis and metastasis in lung adenocarcinoma by regulating AKT/GSK‐3β/β‐catenin signalling

Recent studies have demonstrated that one‐carbon metabolism plays a significant role in cancer development. Methylenetetrahydrofolate dehydrogenase 2 (MTHFD2), a mitochondrial enzyme of one‐carbon metabolism, has been reported to be dysregulated in many cancers. However, the specific role and mechanism of MTHFD2 in lung adenocarcinoma (LUAD) still remains unclear. In this study, we evaluated the clinicopathological and prognostic values of MTHFD2 in LUAD patients. We conducted a series of functional experiments in vivo and in vitro to explore novel mechanism of MTHFD2 in LUAD. The results showed that MTHFD2 was significantly up‐regulated in LUAD tissues and predicted poor prognosis of LUAD patients. Knockdown of MTHFD2 dramatically inhibited cell proliferation and migration by blocking the cell cycle and inducing the epithelial‐mesenchymal transition (EMT). In addition, MTHFD2 knockdown suppressed LUAD growth and metastasis in cell‐derived xenografts. Mechanically, we found that MTHFD2 promoted LUAD cell growth and metastasis via AKT/GSK‐3β/β‐catenin signalling. Finally, we identified miR‐30a‐3p as a novel regulator of MTHFD2 in LUAD. Collectively, MTHFD2 plays an oncogenic role in LUAD progression and is a promising target for LUAD diagnosis and therapy.     

Enhanced Expression of Integrin αvβ3 Induced by TGF-β Is Required for the Enhancing Effect of Fibroblast Growth Factor 1 (FGF1) in TGF-β-Induced Epithelial-Mesenchymal Transition (EMT) in Mammary Epithelial Cells

Epithelial-to-mesenchymal transition (EMT) plays a critical role in cancer metastasis, and is regulated by growth factors such as transforming growth factor β (TGF-β) and fibroblast growth factors (FGF) secreted from the stromal and tumor cells. However, the role of growth factors in EMT has not been fully established. Several integrins are upregulated by TGF-β1 during EMT. Integrins are involved in growth factor signaling through integrin-growth factor receptor crosstalk. We previously reported that FGF1 directly binds to integrin αvβ3 and the interaction was required for FGF1 functions such as cell proliferation and migration. We studied the role of αvβ3 induced by TGF-β on TGF-β-induced EMT. Here, we describe that FGF1 augmented EMT induced by TGF-β1 in MCF10A and MCF12A mammary epithelial cells. TGF-β1 markedly amplified integrin αvβ3 and FGFR1 (but not FGFR2). We studied if the enhancing effect of FGF1 on TGF-β1-induced EMT requires enhanced levels of both integrin αvβ3 expression and FGFR1. Knockdown of β3 suppressed the enhancement by FGF1 of TGF-β1-induced EMT in MCF10A cells. Antagonists to FGFR suppressed the enhancing effect of FGF1 on EMT. Integrin-binding defective FGF1 mutant did not augment TGF-β1-induced EMT in MCF10A cells. These findings suggest that enhanced integrin αvβ3 expression in addition to enhanced FGFR1 expression is critical for FGF1 to augment TGF-β1-induced EMT in mammary epithelial cells.     

miRNA 17 Family Regulates Cisplatin-Resistant and Metastasis by Targeting TGFbetaR2 in NSCLC

MicroRNAs (miRNAs) have been proven to play crucial roles in cancer, including tumor chemotherapy resistance and metastasis of non-small-cell lung cancer (NSCLC). TGFβ signal pathway abnormality is widely found in cancer and correlates with tumor proliferation, apoptosis and metastasis. Here, miR-17, 20a, 20b were detected down-regulated in A549/DDP cells (cisplatin resistance) compared with A549 cells (cisplatin sensitive). Over-expression of miR-17, 20a, 20b can not only decrease cisplatin-resistant but also reduce migration by inhibiting epithelial-to-mesenchymal transition (EMT) in A549/DDP cells. These functions of miR-17, 20a, 20b may be caused at least in part via inhibition of TGFβ signal pathway, as miR-17, 20a, 20b are shown to directly target and repress TGF-beta receptor 2 (TGFβR2) which is an important component of TGFβ signal pathway. Consequently, our study suggests that miRNA 17 family (including miR-17, 20a, 20b) can act as TGFβR2 suppressor for reversing cisplatin-resistant and suppressing metastasis in NSCLC.     

TGF-β induces global changes in DNA methylation during the epithelial-to-mesenchymal transition in ovarian cancer cells

A key step in the process of metastasis is the epithelial-to-mesenchymal transition (EMT). We hypothesized that epigenetic mechanisms play a key role in EMT and to test this hypothesis we analyzed global and gene-specific changes in DNA methylation during TGF-β-induced EMT in ovarian cancer cells. Epigenetic profiling using the Infinium HumanMethylation450 BeadChip (HM450) revealed extensive (P < 0.01) methylation changes after TGF-β stimulation (468 and 390 CpG sites altered at 48 and 120 h post cytokine treatment, respectively). The majority of gene-specific TGF-β-induced methylation changes occurred in CpG islands located in or near promoters (193 and 494 genes hypermethylated at 48 and 120 h after TGF-β stimulation, respectively). Furthermore, methylation changes were sustained for the duration of TGF-β treatment and reversible after the cytokine removal. Pathway analysis of the hypermethylated loci identified functional networks strongly associated with EMT and cancer progression, including cellular movement, cell cycle, organ morphology, cellular development, and cell death and survival. Altered methylation and corresponding expression of specific genes during TGF-β-induced EMT included CDH1 (E-cadherin) and COL1A1 (collagen 1A1). Furthermore, TGF-β induced both expression and activity of DNA methyltransferases (DNMT) -1, -3A, and -3B, and treatment with the DNMT inhibitor SGI-110 prevented TGF-β-induced EMT. These results demonstrate that dynamic changes in the DNA methylome are implicated in TGF-β-induced EMT and metastasis. We suggest that targeting DNMTs may inhibit this process by reversing the EMT genes silenced by DNA methylation in cancer.     

TGF-β1/Smad Signaling Pathway Regulates Epithelial-to-Mesenchymal Transition in Esophageal Squamous Cell Carcinoma: In Vitro and Clinical Analyses of Cell Lines and Nomadic Kazakh Patients from Northwest Xinjiang,China

Invasion and metastasis are the major causes of death in patients with esophageal squamous cell carcinoma (ESCC). Epithelial-mesenchymal transition (EMT) is a critical step in tumor progression and transforming growth factor-β1 (TGF-β1) signaling has been shown to play an important role in EMT. In this study, we investigated how TGF-β1 signaling pathways contributed to EMT in three ESCC cell lines as well as 100 patients of nomadic ethnic Kazakhs residing in northwest Xinjiang Province of China. In vitro analyses included Western blotting to detect the expression of TGF-β1/Smad and EMT-associated proteins in Eca109, EC9706 and KYSE150 cell lines following stimulation with recombinant TGF-β1 and SB431542, a potent inhibitor of ALK5 that also inhibits TGF-β type II receptor. TGF-β-activated Smad2/3 signaling in EMT was significantly upregulated as indicated by mesenchymal markers of N-cadherin and Vimentin, and in the meantime, epithelial marker, E-cadherin, was markedly downregulated. In contrast, SB431542 addition downregulated the expression of N-cadherin and Vimentin, but upregulated the expression of E-cadherin. Moreover, the TGF-β1-induced EMT promoted invasion capability of Eca109 cells. Tumor cells undergoing EMT acquire fibroblastoid-like phenotype. Expressed levels of TGF-β1/Smad signaling molecules and EMT-associated proteins were examined using immunohistochemical analyses in 100 ESCC tissues of Kazakh patients and 58 matched noncancerous adjacent tissues. The results showed that ESCC tissues exhibited upregulated expression of TGF-β1/Smad. We also analyzed the relationship between the above proteins and the patients'' clinicopathological characteristics. The TGF-β1/Smad signaling pathway in human Eca109 ESCC cells may carry similar features as in Kazakh ESCC patients, suggesting that TGF-β1/Smad signaling pathway may be involved in the regulation of EMT in ethnic Kazakh patients with ESCC from Xinjiang, China.     

Col1A1 Production and Apoptotic Resistance in TGF-β1-Induced Epithelial-to-Mesenchymal Transition-Like Phenotype of 603B Cells

Recent studies have suggested that proliferating cholangiocytes have an important role in the induction of fibrosis, either directly via epithelial-to-mesenchymal transition (EMT), or indirectly via activation of other liver cell types. Transforming growth factor beta 1 (TGF-β1), a critical fibrotic cytokine for hepatic fibrosis, is a potent EMT inducer. This study aimed to clarify the potential contributions of TGF-β1-induced EMT-like cholangiocyte phenotype to collagen production and cell survival of cholangiocytes in vitro. Mouse cholangiocytes (603B cells) were treated with TGF-β1 and EMT-like phenotype alterations were monitored by morphological changes and expression of EMT-associated genes. Alterations in Col1A1 gene, Col1A1-associated miR-29s, and pro-apoptotic genes were measured in TGF-β1-treated 603B cells. Snail1 knockdown was achieved using shRNA to evaluate the contribution of EMT-associated changes to Col1A1 production and cell survival. We found TGF-β1 treatment induced partial EMT-like phenotype transition in 603B cells in a Snail1-dependent manner. TGF-β1 also stimulated collagen α1(I) expression in 603B cells. However, this induction was not parallel to the EMT-like alterations and independent of Snail1 or miR-29 expression. Cells undergoing EMT-like changes showed a modest down-regulation of multiple pro-apoptotic genes and displayed resistance to TNF-α-induced apoptosis. TGF-β1-induced apoptosis resistance was attenuated in Snail1 knockdown 603B cells. TGF-β1-induced Col1A1 production seems to be independent of EMT-like transition and miR-29 expression. Nevertheless, TGF-β1-induced EMT may contribute to the increased survival capacity of cholangiocytes via modulating the expression of pro-apoptotic genes.