Deregulation of Negative Controls on TGF-β1 Signaling in Tumor Progression

Ferulic acid lipid nano capsules versus its native form in alleviating diabetic nephropathy induced in rats through TGF-β1/Hippo pathway crosstalk modulation

Diabetic nephropathy is one of the most common leading causes of end-stage renal disease with multifactorial pathophysiological mechanisms. TGF-β1 and Hippo pathway have been reported to have significant role in different kidney diseases. In addition, ferulic acid (FA) has been proposed to have pharmacological actions in different disorders such as Alzheimer, diabetes mellitus, kidney, and cardiovascular diseases but with limited oral use due to poor absorbance and bioavailability. So, recent trends aim to include FA in nano-formulations to improve its absorbance and bioavailability and to make best use of its pharmacological actions when administered orally. Thirty Sprague Dawley male rats were divided into five groups (n = 6). After 28 days, rats were sacrificed, serum and kidney tissue were isolated, histopathological examination, serum creatinine level and oxidative status biomarkers in kidney tissue were estimated, besides ELISA measurements of TGF-β1, PTEN, COX2, and GLUT3 and the relative gene expressions of MST1 and TEAD4 by qRT-PCR. Treated groups show improvement of the investigated parameters in variable degrees. Noteworthy, FA nano-formulation shows superior action over double of the native form.

Combination of high anti-SKI and low anti-TMED5 antibody levels is preferable prognostic factor in esophageal carcinoma

Given that esophageal cancer is highly malignant, the discovery of novel prognostic markers is eagerly awaited. We performed serological identification of antigens by recombinant cDNA expression cloning (SEREX) and identified SKI proto-oncogene protein and transmembrane p24 trafficking protein 5 (TMED5) as antigens recognized by serum IgG antibodies in patients with esophageal carcinoma. SKI and TMED5 proteins were expressed in Escherichia coli, purified by affinity chromatography, and used as antigens. The serum anti-SKI antibody (s-SKI-Ab) and anti-TMED5 antibody (s-TMED5-Ab) levels were significantly higher in 192 patients with esophageal carcinoma than in 96 healthy donors. The presence of s-SKI-Abs and s-TMED5-Abs in the patients' sera was confirmed by western blotting. Immunohistochemical staining showed that the TMED5 protein was highly expressed in the cytoplasm and nuclear compartments of the esophageal squamous cell carcinoma tissues, whereas the SKI protein was localized predominantly in the nuclei. Regarding the overall survival in 91 patients who underwent radical surgery, the s-SKI-Ab-positive and s-TMED5-Ab-negative statuses were significantly associated with a favorable prognosis. Additionally, the combination of s-SKI-Ab-positive and s-TMED5-Ab-negative cases showed an even clearer difference in overall survival as compared with that of s-SKI-Ab-negative and s-TMED5-Ab-positive cases. The s-SKI-Ab and s-TMED5-Ab biomarkers are useful for diagnosing esophageal carcinoma and distinguishing between favorable and poor prognoses.

A chronic signaling TGFb zebrafish reporter identifies immune response in melanoma

Developmental signaling pathways associated with growth factors such as TGFb are commonly dysregulated in melanoma. Here we identified a human TGFb enhancer specifically activated in melanoma cells treated with TGFB1 ligand. We generated stable transgenic zebrafish with this TGFb Induced Enhancer driving green fluorescent protein (TIE:EGFP). TIE:EGFP was not expressed in normal melanocytes or early melanomas but was expressed in spatially distinct regions of advanced melanomas. Single-cell RNA-sequencing revealed that TIE:EGFP+ melanoma cells down-regulated interferon response while up-regulating a novel set of chronic TGFb target genes. ChIP-sequencing demonstrated that AP-1 factor binding is required for activation of chronic TGFb response. Overexpression of SATB2, a chromatin remodeler associated with tumor spreading, showed activation of TGFb signaling in early melanomas. Confocal imaging and flow cytometric analysis showed that macrophages localize to TIE:EGFP+ regions and preferentially phagocytose TIE:EGFP+ melanoma cells compared to TIE:EGFP- melanoma cells. This work identifies a TGFb induced immune response and demonstrates the need for the development of chronic TGFb biomarkers to predict patient response to TGFb inhibitors.

Urinary Excretion of Biomolecules Related to Cell Cycle, Proliferation, and Autophagy in Subjects with Type 2 Diabetes and Chronic Kidney Disease

Dysregulation of cell cycle, proliferation, and autophagy plays a pivotal role in diabetic kidney disease. In this study, we assessed urinary excretion of molecular regulators of these processes that mediate their effects via the PI3K/AKT/mTOR pathway in subjects with long-term type 2 diabetes (T2D) and different patterns of chronic kidney disease (CKD). We included 140 patients with T2D and 20 non-diabetic individuals in a cross-sectional study. Urinary PTEN, Beclin-1, sirtuin 1 (SIRT1), Klotho, fibroblast growth factor 21 (FGF21), and connective tissue growth factor (CTGF) were assessed using ELISA. Patients with T2D, when compared to control, demonstrated increased excretion of PTEN, Beclin-1, SIRT1, FGF21, CTGF, and decreased urinary Klotho (all p < 0.05). In the diabetic group, PTEN, FGF21, and CTGF were significantly higher in patients with declined renal function, while Klotho was lower in those with elevated albuminuria. FGF21 and PTEN correlated inversely with the estimated glomerular filtration rate. There was a negative correlation between Klotho and urinary albumin-to-creatinine ratio. In multivariate models, Klotho and PTEN were associated with albuminuric CKD independently. The results provide further support for the role of PTEN, BECN1, FGF21, Klotho, and CTGF in development albuminuric and non-albuminuric CKD in diabetes.

The Efficacy and Safety of Polyethylene Glycol Cholesterol- and Tocopherol Polyethylene Glycol 1000 Succinate-Modified Transforming Growth Factor β1 Small Interfering RNA Lipid Nanoparticles in the Treatment of Paclitaxel-Resistant Non-Small-Cell Lung Cancer

The aim of this study was to explore the efficacy and safety of TGFβ1 siRNA lipid nanoparticles (LNPs) modified with different PEG derivatives (PEG5000 cholesterol, abbreviated as CE; tocopherol polyethylene glycol 1000 succinate, abbreviated as TPGS) in the treatment of paclitaxel-resistant non-small-cell lung cancer. Three kinds of TGFβ1 siRNA LNPs were prepared via microfluidics technology, using different PEG derivatives and dosages (CE1.5, CE2.5, TPGS2.5) as variables. Their particle size, zeta potential, contents, and encapsulation efficiencies were determined. The inhibition of TGFβ1 mRNA and protein expression and the effects of the three kinds of LNPs on the proliferation of paclitaxel-resistant non-small-cell lung cancer cells (A549/T cell) were characterized. The distributions of the three siRNA LNPs in nude mice bearing A549/T tumors, especially at the tumor site, were observed using in vivo mouse imaging technology, and their corresponding efficacies were evaluated. The average particle size of the three kinds of TGFβ1 siRNA LNPs was about 70-80 nm, and they were capable of charge flipping. All three siRNA LNPs could effectively inhibit the expression of TGFβ1 mRNA and protein in A549/T cells and inhibit the proliferation of A549/T cells in vitro. The results of in vivo mice imaging showed that the three kinds of siRNA LNPs, when labeled with cypate, retain strong fluorescence in the tumor at 24 h. The pharmacodynamic results, such as for relative tumor volumes and tumor inhibition rates, reveal that TGFβ1 siRNA LNPs modified with CE1.5, CE2.5, or TPGS2.5 can be used to effectively treat paclitaxel-resistant lung adenocarcinoma. The histopathological results showed that the three kinds of LNPs have a certain toxicity but are relatively safe compared to common forms of chemotherapy such as cabazitaxel. TGFβ1 siRNA LNPs modified with CE1.5, CE2.5, and TPGS2.5 can inhibit TGFβ1 mRNA and protein expression in A549/T cells in vitro and can accumulate and play a role in the tumor tissue of nude mice, features that can be exploited for treating paclitaxel-resistant lung adenocarcinoma.

Remodeled tumor immune microenvironment (TIME) parade via natural killer cells reprogramming in breast cancer

Breast cancer (BC) is the main cause of cancer-related mortality among women globally. Despite substantial advances in the identification and management of primary tumors, traditional therapies including surgery, chemotherapy, and radiation cannot completely eliminate the danger of relapse and metastatic illness. Metastasis is controlled by microenvironmental and systemic mechanisms, including immunosurveillance. This led to the evolvement of immunotherapies that has gained much attention in the recent years for cancer treatment directed to the innate immune system. The long forgotten innate immune cells known as natural killer (NK) cells have emerged as novel targets for more effective therapeutics for BC. Normally, NK cells has the capacity to identify and eradicate tumor cells either directly or by releasing cytotoxic granules, chemokines and proinflammatory cytokines. Yet, NK cells are exposed to inhibitory signals by cancer cells, which causes them to become dysfunctional in the immunosuppressive tumor microenvironment (TME) in BC, supporting tumor escape and spread. Potential mechanisms of NK cell dysfunction in BC metastasis have been recently identified. Understanding these immunologic pathways driving BC metastasis will lead to improvements in the current immunotherapeutic strategies. In the current review, we highlight how BC evades immunosurveillance by rendering NK cells dysfunctional and we shed the light on novel NK cell- directed therapies.

MicroRNAs as prospective biomarkers, therapeutic targets and pharmaceuticals in neuroblastoma

Neuroblastomas, the most prevalent malignant solid neoplasms of childhood, originate from progenitor cells of the sympathetic nervous system. Their genetic causation is diverse and involves multiple molecular mechanisms. This review highlights multiple roles of microRNA in neuroblastoma pathogenesis and discusses the prospects of harnessing these important natural regulator molecules as biomarkers, therapeutic targets and pharmaceuticals in neuroblastoma.

Therapeutic Potential of Targeting Transforming Growth Factor-beta (TGF-β) and Programmed Death-ligand 1 (PD-L1) in Pancreatic Cancer

Pancreatic cancer (PC) is one the most lethal malignancies worldwide affecting around half a million individuals each year. The treatment of PC is relatively difficult due to the difficulty in making an early diagnosis. Transforming growth factor-beta (TGF-β) is a multifunctional factor acting as both a tumor promoter in early cancer stages and a tumor suppressor in advanced disease. Programmed death-ligand 1 (PD-L1) is a ligand of programmed death-1 (PD-1), an immune checkpoint receptor, allowing tumor cells to avoid elimination by immune cells. Recently, targeting the TGF-β signaling and PD-L1 pathways has emerged as a strategy for cancer therapy. In this review, we have summarized the current knowledge regarding these pathways and their contribution to tumor development with a focus on PC. Moreover, we have reviewed the role of TGF-β and PD-L1 blockade in the treatment of various cancer types, including PC, and discussed the clinical trials evaluating TGF-β and PD-L1 antagonists in PC patients.

Role of non-coding RNAs and exosomal non-coding RNAs in retinoblastoma progression

Retinoblastoma (RB) is a rare aggressive intraocular malignancy of childhood that has the potential to affect vision, and can even be fatal in some children. While the tumor can be controlled efficiently at early stages, metastatic tumors lead to high mortality. Non-coding RNAs (ncRNAs) are implicated in a number of physiological cellular process, including differentiation, proliferation, migration, and invasion, The deregulation of ncRNAs is correlated with several diseases, particularly cancer. ncRNAs are categorized into two main groups based on their length, i.e. short and long ncRNAs. Moreover, ncRNA deregulation has been demonstrated to play a role in the pathogenesis and development of RB. Several ncRNAs, such as miR-491-3p, miR-613,and SUSD2 have been found to act as tumor suppressor genes in RB, but other ncRNAs, such as circ-E2F3, NEAT1, and TUG1 act as tumor promoter genes. Understanding the regulatory mechanisms of ncRNAs can provide new opportunities for RB therapy. In the present review, we discuss the functional roles of the most important ncRNAs in RB, their interaction with the genes responsible for RB initiation and progression, and possible future clinical applications as diagnostic and prognostic tools or as therapeutic targets.

Targeting TGF-β signaling in the multiple myeloma microenvironment: Steering CARs and T cells in the right direction

Multiple myeloma (MM) remains a lethal hematologic cancer characterized by the expansion of transformed plasma cells within the permissive bone marrow (BM) milieu. The emergence of relapsed and/or refractory MM (RRMM) is provoked through clonal evolution of malignant plasma cells that harbor genomic, metabolic and proteomic perturbations. For most patients, relapsed disease remains a major cause of overall mortality. Transforming growth factors (TGFs) have pleiotropic effects that regulate myelomagenesis as well as the emergence of drug resistance. Moreover, TGF-β modulates numerous cell types present with the tumor microenvironment, including many immune cell types. While numerous agents have been FDA-approved over the past 2 decades and significantly expanded the treatment options available for MM patients, the molecular mechanisms responsible for drug resistance remain elusive. Multiple myeloma is uniformly preceded by a premalignant state, monoclonal gammopathy of unknown significance, and both conditions are associated with progressive deregulation in host immunity characterized by reduced T cell, natural killer (NK) cell and antigen-presenting dendritic cell (DC) activity. TGF-β promotes myelomagenesis as well as intrinsic drug resistance by repressing anti-myeloma immunity to promote tolerance, drug resistance and disease progression. Hence, repression of TGF-β signaling is a prerequisite to enhance the efficacy of current and future immunotherapeutics. Novel strategies that incorporate T cells that have been modified to express chimeric antigen receptor (CARs), T cell receptors (TCRs) and bispecific T cell engagers (BiTEs) offer promise to block TGF-β signaling, overcome chemoresistance and enhance anti-myeloma immunity. Here, we describe the effects of TGF-β signaling on immune cell effectors in the bone marrow and emerging strategies to overcome TGF-β-mediated myeloma growth, drug resistance and survival.

BMP and activin membrane-bound inhibitor regulate connective tissue growth factor controlling mesothelioma cell proliferation

Background

Malignant mesothelioma (MM) is an aggressive mesothelial cell cancer type linked mainly to asbestos inhalation. MM characterizes by rapid progression and resistance to standard therapeutic modalities such as surgery, chemotherapy, and radiotherapy. Our previous studies have suggested that tumor cell-derived connective tissue growth factor (CTGF) regulates the proliferation of MM cells as well as the tumor growth in mouse xenograft models.

Methods

In this study, we knock downed the bone morphogenetic protein and activin membrane-bound inhibitor (BAMBI) and CTGF in MM cells and investigated the relationship between both and their impact on the cell cycle and cell proliferation.

Results

The knockdown of CTGF or BAMBI reduced MM cell proliferation. In contrast to CTGF knockdown which decreased BAMBI, knockdown of BAMBI increased CTGF levels. Knockdown of either BAMBI or CTGF reduced expression of the cell cycle regulators; cyclin D3, cyclin-dependent kinase (CDK)2, and CDK4. Further, in silico analysis revealed that higher BAMBI expression was associated with shorter overall survival rates among MM patients.

Conclusions

Our findings suggest that BAMBI is regulated by CTGF promoting mesothelioma growth by driving cell cycle progression. Therefore, the crosstalk between BAMBI and CTGF may be an effective therapeutic target for MM treatment.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-10080-x.

Use of miRNA Sequencing to Reveal Hub miRNAs and the Effect of miR-582-3p/SMAD2 in the Progression of Hepatocellular Carcinoma

Hepatocellular carcinoma is a common tumor with a high fatality rate worldwide, and exploring its pathogenesis and deterioration mechanism is a focus for many researchers. Increasing evidence has shown that miRNAs are involved in the occurrence and progression of a variety of cancers, including hepatocellular carcinoma. Therefore, this study mainly aimed identify key miRNAs related to hepatocellular carcinoma and explore their potential functions and clinical significance. In this study, we performed miRNA sequencing on three pairs of hepatocellular carcinoma tissue samples and screened 26 differentially expressed miRNAs. Then 2 key miRNAs (miR-139-5p and miR-582-3p) were screened by Kaplan-Meier curve analysis, Cox multivariate analysis and qPCR methods. The expression of miR-582-3p was positively correlated with clinicopathological parameters in patients with hepatocellular carcinoma. Subsequently, miRwalk and starbase were used to predict the target genes of key miRNAs, and then the key pairs miR-582-3p/SMAD2 identified by WGCNA, PPI, qPCR and Pearson correlation analysis. Finally, a dual luciferase experiment, the rescue-of-function experiment and qPCR confirmed that miR-582-3p directly targets SMAD2 and regulates the proliferation, migration and invasion of HepG2 cells by targeting SMAD2. At the same time, interference with SMAD2 can influence the effect of miR-582-3p on HepG2 cells. In conclusion, our findings confirm that miR-582-3p is an independent factor for the prognosis of hepatocellular carcinoma patients, and can regulate the progression of hepatocellular carcinoma cells by targeting SMAD2.

BMP-7 ameliorates partial epithelial-mesenchymal transition by restoring SnoN protein level via Smad1/5 pathway in diabetic kidney disease

Tubulointerstitial fibrosis (TIF) is involved in the development of diabetic kidney disease (DKD). Transforming growth factor β1 (TGF-β1) is involved in the extensive fibrosis of renal tissue by facilitating the partial epithelial-mesenchymal transition (EMT), increasing the synthesis of extracellular matrix (ECM), inhibiting degradation, inducing apoptosis of renal parenchyma cells, and activating renal interstitial fibroblasts and inflammatory cells. Recent studies indicated that bone morphogenetic protein-7 (BMP-7) upregulated the expression of endogenous SnoN against renal TIF induced by TGF-β1 or hyperglycemia. Nevertheless, the mechanisms underlying the BMP-7-mediated restoration of SnoN protein level remains elusive. The present study demonstrated the increased expression of BMP-7 in diabetic mellitus (DM) mice by hydrodynamic tail vein injection of overexpressed BMP-7 plasmid, which attenuated the effects of DM on kidney in mice. Partial tubular EMT and the accumulation of Collagen-III were resisted in DM mice that received overexpressed BMP-7 plasmid. Similar in vivo results showed that BMP-7 was competent to alleviate NRK-52E cells undergoing partial EMT in a high-glucose milieu. Furthermore, exogenous BMP-7 activated the Smad1/5 pathway to promote gene transcription of SnoN and intervened ubiquitination of SnoN; both effects repaired the SnoN protein level in renal tubular cells and kidney tissues of DM mice. Therefore, these findings suggested that BMP-7 could upregulate SnoN mRNA and protein levels by activating the classical Smad1/5 pathway to refrain from the partial EMT of renal tubular epithelial cells and the deposition of ECM in DKD-induced renal fibrosis.

The Bright and the Dark Side of TGF-β Signaling in Hepatocellular Carcinoma: Mechanisms, Dysregulation, and Therapeutic Implications

Simple Summary

Transforming growth factor β (TGF-β) signaling is a preeminent regulator of diverse cellular and physiological processes. Frequent dysregulation of TGF-β signaling has been implicated in cancer. In hepatocellular carcinoma (HCC), the most prevalent form of primary liver cancer, the autocrine and paracrine effects of TGF-β have paradoxical implications. While acting as a potent tumor suppressor pathway in the early stages of malignancy, TGF-β diverts to a promoter of tumor progression in the late stages, reflecting its bright and dark natures, respectively. Within this context, targeting TGF-β represents a promising therapeutic option for HCC treatment. We discuss here the molecular properties of TGF-β signaling in HCC, attempting to provide an overview of its effects on tumor cells and the stroma. We also seek to evaluate the dysregulation mechanisms that mediate the functional switch of TGF-β from a tumor suppressor to a pro-tumorigenic signal. Finally, we reconcile its biphasic nature with the therapeutic implications.

Abstract

Hepatocellular carcinoma (HCC) is associated with genetic and nongenetic aberrations that impact multiple genes and pathways, including the frequently dysregulated transforming growth factor β (TGF-β) signaling pathway. The regulatory cytokine TGF-β and its signaling effectors govern a broad spectrum of spatiotemporally regulated molecular and cellular responses, yet paradoxically have dual and opposing roles in HCC progression. In the early stages of tumorigenesis, TGF-β signaling enforces profound tumor-suppressive effects, primarily by inducing cell cycle arrest, cellular senescence, autophagy, and apoptosis. However, as the tumor advances in malignant progression, TGF-β functionally switches to a pro-tumorigenic signal, eliciting aggressive tumor traits, such as epithelial–mesenchymal transition, tumor microenvironment remodeling, and immune evasion of cancer cells. On this account, the inhibition of TGF-β signaling is recognized as a promising therapeutic strategy for advanced HCC. In this review, we evaluate the functions and mechanisms of TGF-β signaling and relate its complex and pleiotropic biology to HCC pathophysiology, attempting to provide a detailed perspective on the molecular determinants underlying its functional diversion. We also address the therapeutic implications of the dichotomous nature of TGF-β signaling and highlight the rationale for targeting this pathway for HCC treatment, alone or in combination with other agents.

Long non-coding RNA SND1-IT1 accelerates cell proliferation, invasion and migration via regulating miR-132-3p/SMAD2 axis in retinoblastoma

Long noncoding RNAs (lncRNAs) have been identified as prognostic biomarkers and functional regulators in human tumors. In our study, we aim to investigate the roles of lncRNA SND1-IT1 (SND1-IT1) in retinoblastoma (RB). We observed that SND1-IT1 was highly expressed in both RB specimens and cells, and associated with poorer prognosis of RB patients. Functional investigation revealed that downregulation of SND1-IT1 suppressed RB cell proliferation, migration and invasion in vitro and restrained RB tumorigenesis in vivo. MiR-132-3p was predicted to interact with SND1-IT1. RT-qPCR and dual-luciferase reporter assays verified the regulation of miR-132-3p by SND1-IT1 in RB cells. In addition, SND1-IT1 enhanced the expression of SMAD2 by sponging miR-132-3p. Rescue experiments revealed that knockdown of miR-132-3p reversed the inhibiting effects of miR-132-3p knockdown on RB cells. Overall, SND1-IT1 can promote the progression of RB cells through miR-132-3p/SMAD2 axis, suggesting that l SND1-IT1 might be a novel biomarker and potential target for RB.

Overcoming Therapy Resistance and Relapse in TNBC: Emerging Technologies to Target Breast Cancer-Associated Fibroblasts

Breast cancer is the most diagnosed cancer and is the leading cause of cancer mortality in women. Triple-negative breast cancer (TNBC) is an aggressive form of breast cancer. Often, TNBC is not effectively treated due to the lack of specificity of conventional therapies and results in relapse and metastasis. Breast cancer-associated fibroblasts (BCAFs) are the predominant cells that reside in the tumor microenvironment (TME) and regulate tumorigenesis, progression and metastasis, and therapy resistance. BCAFs secrete a wide range of factors, including growth factors, chemokines, and cytokines, some of which have been proved to lead to a poor prognosis and clinical outcomes. This TME component has been emerging as a promising target due to its crucial role in cancer progression and chemotherapy resistance. A number of therapeutic candidates are designed to effectively target BCAFs with a focus on their tumor-promoting properties and tumor immune response. This review explores various agents targeting BCAFs in TNBC, including small molecules, nucleic acid-based agents, antibodies, proteins, and finally, nanoparticles.

A narrative review of the relationship between TGF-β signaling and gynecological malignant tumor

Objective

This paper reviews the association between transforming growth factor-β (TGF-β) and its receptor and tumor, focusing on gynecological malignant tumors. we hope to provide more methods to help increase the potential of TGF-β signaling targeted treatment of specific cancers.

Background

The occurrence of a malignant tumor is a complex process of multi-step, multi-gene regulation, and its progression is affected by various components of the tumor cells and/or tumor microenvironment. The occurrence of gynecological diseases not only affect women's health, but also bring some troubles to their normal life. Especially when gynecological malignant tumors occur, the situation is more serious, which will endanger the lives of patients. Due to differences in environmental and economic conditions, not all women have access to assistance and treatment specifically meeting their needs. TGF-β is a multi-potent growth factor that maintains homeostasis in mammals by inhibiting cell growth and promoting apoptosis in vivo. TGF-β signaling is fundamental to inflammatory disease and favors the emergence of tumors, and it also plays an important role in immunosuppression in the tumor microenvironment. In the early stages of the tumor, TGF-β acts as a tumor inhibitor, whereas in advanced tumors, mutations or deletion of the TGF-β signaling core component initiate neogenesis.

Methods

Literatures about TGF-β and gynecological malignant tumor were extensively reviewed to analyze and discuss.

Conclusions

We discussed the role of TGF-β signaling in different types of gynecological tumor cells, thus demonstrating that targeted TGF-β signaling may be an effective tumor treatment strategy.

MIR21-induced loss of junctional adhesion molecule A promotes activation of oncogenic pathways, progression and metastasis in colorectal cancer

Junctional adhesion molecules (JAMs) play a critical role in cell permeability, polarity and migration. JAM-A, a key protein of the JAM family, is altered in a number of conditions including cancer; however, consequences of JAM-A dysregulation on carcinogenesis appear to be tissue dependent and organ dependent with significant implications for the use of JAM-A as a biomarker or therapeutic target. Here, we test the expression and prognostic role of JAM-A downregulation in primary and metastatic colorectal cancer (CRC) (n = 947). We show that JAM-A downregulation is observed in ~60% of CRC and correlates with poor outcome in four cohorts of stages II and III CRC (n = 1098). Using JAM-A knockdown, re-expression and rescue experiments in cell line monolayers, 3D spheroids, patient-derived organoids and xenotransplants, we demonstrate that JAM-A silencing promotes proliferation and migration in 2D and 3D cell models and increases tumour volume and metastases in vivo. Using gene-expression and proteomic analyses, we show that JAM-A downregulation results in the activation of ERK, AKT and ROCK pathways and leads to decreased bone morphogenetic protein 7 expression. We identify MIR21 upregulation as the cause of JAM-A downregulation and show that JAM-A rescue mitigates the effects of MIR21 overexpression on cancer phenotype. Our results identify a novel molecular loop involving MIR21 dysregulation, JAM-A silencing and activation of multiple oncogenic pathways in promoting invasiveness and metastasis in CRC.

RanBP3 Regulates Proliferation, Apoptosis and Chemosensitivity of Chronic Myeloid Leukemia Cells via Mediating SMAD2/3 and ERK1/2 Nuclear Transport

Abnormal subcellular localization of proteins is an important cause of tumorigenesis and drug resistance. Chromosome region maintenance 1 (CRM1), the nuclear export regulator of most proteins, has been confirmed to be over-expressed in various malignancies and is regarded as an efficient target. But the potential role of the CRM1 cofactor RanBP3 (Ran Binding Protein 3) is left unrevealed in chronic myeloid leukemia (CML). Here, we first detected the level of RanBP3 in CML and found an elevated RanBP3 expression in CML compared with control. Then we used shRNA lentivirus to down-regulated RanBP3 in imatinib sensitive K562 cells and resistant K562/G01 cells and found RanBP3 silencing inhibited cell proliferation by up-regulating p21, induced caspase3-related cell apoptosis, and enhanced the drug sensitivity of IM in vitro. Notably, we observed that RanBP3 silencing restored imatinib sensitivity of K562 cells in NOD/SCID mice. Mechanistically, the nuclear aggregation of SMAD2/3 revealed that tumor suppressor axis (TGF-β)-SMAD2/3-p21 was the anti-proliferation program related to RanBP3 knockdown, and the decrease of cytoplasmic ERK1/2 caused by RanBP3 interference leaded to the down-regulation of anti-apoptosis protein p(Ser112)-BAD, which was the mechanism of increased cell apoptosis and enhanced chemosensitivity to imatinib in CML. In summary, this study revealed the expression and potential role of RanBP3 in CML, suggesting that targeting RanBP3 alone or combined with TKIs could improve the clinical response of CML.

Alterations in TGFβ signaling during prostate cancer progression

During prostate cancer progression, TGF-β acts as both a tumor suppressor and tumor promoter. TGF-β inhibits cell proliferation in normal and early-stage prostate cancer cells, but during later stages of the disease the cancer cells develop resistance to inhibitory effects on cell proliferation. In these cells, TGF-β promotes cancer progression due to its effects on epithelial to mesenchymal transition (EMT), cell migration and invasion, and immune suppression. The intracellular mechanisms involved in the development of resistance to TGF-β effects on cell proliferation are largely unknown. In this review, we summarized the roles of several intracellular proteins including PTEN, Id1 and JunD, which may play a role in this transition. The role of Ski/SnoN proteins in inhibition of Smad2/3 signaling is highlighted.

Negative regulators of TGF-β1 signaling in renal fibrosis; pathological mechanisms and novel therapeutic opportunities

Elevated expression of the multifunctional cytokine transforming growth factor β1 (TGF-β1) is causatively linked to kidney fibrosis progression initiated by diabetic, hypertensive, obstructive, ischemic and toxin-induced injury. Therapeutically relevant approaches to directly target the TGF-β1 pathway (e.g., neutralizing antibodies against TGF-β1), however, remain elusive in humans. TGF-β1 signaling is subjected to extensive negative control at the level of TGF-β1 receptor, SMAD2/3 activation, complex assembly and promoter engagement due to its critical role in tissue homeostasis and numerous pathologies. Progressive kidney injury is accompanied by the deregulation (loss or gain of expression) of several negative regulators of the TGF-β1 signaling cascade by mechanisms involving protein and mRNA stability or epigenetic silencing, further amplifying TGF-β1/SMAD3 signaling and fibrosis. Expression of bone morphogenetic proteins 6 and 7 (BMP6/7), SMAD7, Sloan-Kettering Institute proto-oncogene (Ski) and Ski-related novel gene (SnoN), phosphate tensin homolog on chromosome 10 (PTEN), protein phosphatase magnesium/manganese dependent 1A (PPM1A) and Klotho are dramatically decreased in various nephropathies in animals and humans albeit with different kinetics while the expression of Smurf1/2 E3 ligases are increased. Such deregulations frequently initiate maladaptive renal repair including renal epithelial cell dedifferentiation and growth arrest, fibrotic factor (connective tissue growth factor (CTGF/CCN2), plasminogen activator inhibitor type-1 (PAI-1), TGF-β1) synthesis/secretion, fibroproliferative responses and inflammation. This review addresses how loss of these negative regulators of TGF-β1 pathway exacerbates renal lesion formation and discusses the therapeutic value in restoring the expression of these molecules in ameliorating fibrosis, thus, presenting novel approaches to suppress TGF-β1 hyperactivation during chronic kidney disease (CKD) progression.

Perception of breast cancer risk factors: Dysregulation of TGF-β/miRNA axis in Pakistani females

Breast cancer poses a serious health risk for women throughout the world. Among the Asian population, Pakistani women have the highest risk of developing breast cancer. One out of nine women is diagnosed with breast cancer in Pakistan. The etiology and the risk factor leading to breast cancer are largely unknown. In the current study the risk factors that are most pertinent to the Pakistani population, the etiology, molecular mechanisms of tumor progression, and therapeutic targets of breast cancer are studied. A correlative, cross-sectional, descriptive, and questionnaire-based study was designed to predict the risk factors in breast cancer patients. Invasive Ductal Carcinoma (90%) and grade-II tumor (73.2%) formation are more common in our patient’s data set. Clinical parameters such as mean age of 47.5 years (SD ± 11.17), disturbed menstrual cycle (> 2), cousin marriages (repeated), and lactation period (< 0.5 Y) along with stress, dietary and environmental factors have an essential role in the development of breast cancer. In addition to this in silico analysis was performed to screen the miRNA regulating the TGF-beta pathway using TargetScanHuman, and correlation was depicted through Mindjet Manager. The information thus obtained was observed in breast cancer clinical samples both in peripheral blood mononuclear cells, and biopsy through quantitative real-time PCR. There was a significant dysregulation (**P>0.001) of the TGF-β1 signaling pathway and the miRNAs (miR-29a, miR-140, and miR-148a) in patients’ biopsy in grade and stage specifically, correlated with expression in blood samples. miRNAs (miR-29a and miR-140, miR-148a) can be an effective diagnostic and prognostic marker as they regulate SMAD4 and SMAD2 expression respectively in breast cancer blood and biopsy samples. Therefore, proactive therapeutic strategies can be devised considering negatively regulated cascade genes and amalgamated miRNAs to control breast cancer better.

The Genomic Response to TGF-β1 Dictates Failed Repair and Progression of Fibrotic Disease in the Obstructed Kidney

Tubulointerstitial fibrosis is a common and diagnostic hallmark of a spectrum of chronic renal disorders. While the etiology varies as to the causative nature of the underlying pathology, persistent TGF-β1 signaling drives the relentless progression of renal fibrotic disease. TGF-β1 orchestrates the multifaceted program of kidney fibrogenesis involving proximal tubular dysfunction, failed epithelial recovery or re-differentiation, capillary collapse and subsequent interstitial fibrosis eventually leading to chronic and ultimately end-stage disease. An increasing complement of non-canonical elements function as co-factors in TGF-β1 signaling. p53 is a particularly prominent transcriptional co-regulator of several TGF-β1 fibrotic-response genes by complexing with TGF-β1 receptor-activated SMADs. This cooperative p53/TGF-β1 genomic cluster includes genes involved in cellular proliferative control, survival, apoptosis, senescence, and ECM remodeling. While the molecular basis for this co-dependency remains to be determined, a subset of TGF-β1-regulated genes possess both p53- and SMAD-binding motifs. Increases in p53 expression and phosphorylation, moreover, are evident in various forms of renal injury as well as kidney allograft rejection. Targeted reduction of p53 levels by pharmacologic and genetic approaches attenuates expression of the involved genes and mitigates the fibrotic response confirming a key role for p53 in renal disorders. This review focuses on mechanisms underlying TGF-β1-induced renal fibrosis largely in the context of ureteral obstruction, which mimics the pathophysiology of pediatric unilateral ureteropelvic junction obstruction, and the role of p53 as a transcriptional regulator within the TGF-β1 repertoire of fibrosis-promoting genes.

Normal cells repel WWOX-negative or -dysfunctional cancer cells via WWOX cell surface epitope 286-299

Metastatic cancer cells are frequently deficient in WWOX protein or express dysfunctional WWOX (designated WWOXd). Here, we determined that functional WWOX-expressing (WWOXf) cells migrate collectively and expel the individually migrating WWOXd cells. For return, WWOXd cells induces apoptosis of WWOXf cells from a remote distance. Survival of WWOXd from the cell-to-cell encounter is due to activation of the survival IκBα/ERK/WWOX signaling. Mechanistically, cell surface epitope WWOX286-299 (repl) in WWOXf repels the invading WWOXd to undergo retrograde migration. However, when epitope WWOX7-21 (gre) is exposed, WWOXf greets WWOXd to migrate forward for merge. WWOX binds membrane type II TGFβ receptor (TβRII), and TβRII IgG-pretreated WWOXf greet WWOXd to migrate forward and merge with each other. In contrast, TβRII IgG-pretreated WWOXd loses recognition by WWOXf, and WWOXf mediates apoptosis of WWOXd. The observatons suggest that normal cells can be activated to attack metastatic cancer cells. WWOXd cells are less efficient in generating Ca²⁺ influx and undergo non-apoptotic explosion in response to UV irradiation in room temperature. WWOXf cells exhibit bubbling cell death and Ca²⁺ influx effectively caused by UV or apoptotic stress. Together, membrane WWOX/TβRII complex is needed for cell-to-cell recognition, maintaining the efficacy of Ca²⁺ influx, and control of cell invasiveness.

PPM1A suppresses the proliferation and invasiveness of RCC cells via Smad2/3 signaling inhibition

BACKGROUND

Cytokine therapies show promise in treating renal cell carcinoma (RCC). Transforming growth factor beta 1 (TGF-β1) is a cytokine whose downstream Smad2/3 signaling activity is inhibited by the protein phosphatase Mg2+/Mn2+-dependent 1 A (PPM1A). Here, we hypothesized that PPM1A may be involved in suppressing RCC cell aggressiveness through its negative regulation of Smad2/3.

METHODS

We quantified PPM1A expression from RCC tumors and matching healthy tissue and performed a Kaplan-Meier survival analysis. In silico analysis on PPM1A was performed using Cancer Genome Atlas-Kidney Renal Clear Cell Carcinoma and Clinical Proteomic Tumor Analysis Consortium RCC cohort data. We tested four RCC cell lines and selected the ACNH and A498 cells lines as expressing the greatest PPM1A levels. We assayed the effects of RNAi-mediated PPM1A silencing on invasiveness, proliferation, colony formation, and Smad2/3 phosphorylation in untreated and TGF-β1-stimulated ACNH and A498 cells. A nude mouse A498 xenograft tumor model was constructed to validate PPM1A's effects in vivo.

RESULTS

PPM1A levels are reduced in RCC tumors and are negatively correlated with RCC grade and stage. Below-median PPM1A expression is associated with reduced overall survival in RCC patients. PPM1A silencing promoted cellular invasiveness, proliferation, colony formation, and Smad2/3 phosphorylation under TGF-β1-stimulated conditions but not under untreated conditions. These effects of PPM1A were shown to be dependent on Smad2/3. Intratumor PPM1A overexpression inhibited A498 xenograft tumor growth.

CONCLUSIONS

This study establishes a direct link between PPM1A's suppression of Smad2/3 signaling and RCC cell aggressiveness. PPM1A could potentially serve as a biomarker for RCC cell aggressiveness.

Expression and function of Smad7 in autoimmune and inflammatory diseases

Transforming growth factor-β (TGF-β) plays a critical role in the pathological processes of various diseases. However, the signaling mechanism of TGF-β in the pathological response remains largely unclear. In this review, we discuss advances in research of Smad7, a member of the I-Smads family and a negative regulator of TGF-β signaling, and mainly review the expression and its function in diseases. Smad7 inhibits the activation of the NF-κB and TGF-β signaling pathways and plays a pivotal role in the prevention and treatment of various diseases. Specifically, Smad7 can not only attenuate growth inhibition, fibrosis, apoptosis, inflammation, and inflammatory T cell differentiation, but also promotes epithelial cells migration or disease development. In this review, we aim to summarize the various biological functions of Smad7 in autoimmune diseases, inflammatory diseases, cancers, and kidney diseases, focusing on the molecular mechanisms of the transcriptional and posttranscriptional regulation of Smad7.

miR-720 is a key regulator of glioma migration and invasion by controlling TARSL2 expression

Glioblastoma (GBM) is the most lethal type of primary brain tumor and is characterized by diffuse infiltrative growth. However, the mechanisms that control this phenotype remain largely unknown. Emerging evidence has demonstrated that the abnormal expression of microRNAs and their target genes are involved in the migration and invasion of glioma cells. In this study, we demonstrated that microRNA-720 (miR-720) was significantly upregulated in glioma tissues and cells. Functional experiments showed that overexpression of miR-720 promotes glioma migration and invasion, while downregulation of miR-720 inhibits glioma migration and invasion. Meanwhile, we found that threonyl-tRNA synthetase like-2 (TARSL2) was a direct and functional target of miR-720 in glioma. Reintroduction of TARSL2 into glioma cells repressed the invasion promoting function of miR-720, whereas downregulation of TARSL2 reversed the anti-invasion function of anti-miR-720. Furthermore, quantitative real-time polymerase chain reaction results showed that miR-720 was inversely correlated with TARSL2 expression in 40 GBM tissues. Finally, in vivo experiments showed that miR-720 promotes glioma growth and upregulates invasion-related genes in nude mice. Overall, our findings suggest increasing miR-720 enhances glioma migration and invasion through downregulation of TARSL2, which may provide novel insight into the treatment of glioma.

TGFβ1: An Indicator for Tumor Immune Microenvironment of Colon Cancer From a Comprehensive Analysis of TCGA

BACKGROUND

Tumor microenvironment (TME) and tumor-infiltrating immune cells (TICs) greatly participate in the genesis and development of colon cancer (CC). However, there is little research exploring the dynamic modulation of TME.

METHODS

We analyzed the proportion of immune/stromal component and TICs in the TME of 473 CC samples and 41 normal samples from The Cancer Genome Atlas (TCGA) database through ESTIMATE and CIBERSORT algorithms. Correlation analysis was conducted to evaluate the association between immune/stromal component in the TME and clinicopathological characteristics of CC patients. The difference analysis was performed to obtain the differentially expressed genes (DEGs). These DEGs were further analyzed by GO and KEGG enrichment analyses, PPI network, and COX regression analysis. Transforming growth factor β1 (TGFβ1) was finally overlapped from the above analysis. Paired analysis and GSEA were carried out to understand the role of TGFβ1 in colon cancer. The intersection between the difference analysis and correlation analysis was conducted to learn the association between TGFβ1 and TICs.

RESULTS

Our results showed that the immune component in the TME was negatively related with the stages of CC. GO and KEGG enrichment analysis revealed that 1,110 DEGs obtained from the difference analysis were mainly enriched in immune-related activities. The intersection analysis between PPI network and COX regression analysis indicated that TGFβ1 was significantly associated with the communication of genes in the PPI network and the survival of CC patients. In addition, TGFβ1 was up-regulated in the tumor samples and significantly related with poor prognosis of CC patients. Further GSEA suggested that genes in the TGFβ1 up-regulated group were enriched in immune-related activities and the function of TGFβ1 might depend on the communications with TICs, including T cells CD4 naïve and T cells regulatory.

CONCLUSION

The expression of TGFβ1 might be an indicator for the tumor immune microenvironment of CC and serve as a prognostic factor. Drugs targeting TGFβ1 might be a potential immunotherapy for CC patients in the future.

Novel therapies emerging in oncology to target the TGF-β pathway

The TGF-β signaling pathway governs key cellular processes under physiologic conditions and is deregulated in many pathologies, including cancer. TGF-β is a multifunctional cytokine that acts in a cell- and context-dependent manner as a tumor promoter or tumor suppressor. As a tumor promoter, the TGF-β pathway enhances cell proliferation, migratory invasion, metastatic spread within the tumor microenvironment and suppresses immunosurveillance. Collectively, the pleiotropic nature of TGF-β signaling contributes to drug resistance, tumor escape and undermines clinical response to therapy. Based upon a wealth of preclinical studies, the TGF-β pathway has been pharmacologically targeted using small molecule inhibitors, TGF-β-directed chimeric monoclonal antibodies, ligand traps, antisense oligonucleotides and vaccines that have been now evaluated in clinical trials. Here, we have assessed the safety and efficacy of TGF-β pathway antagonists from multiple drug classes that have been evaluated in completed and ongoing trials. We highlight Vactosertib, a highly potent small molecule TGF-β type 1 receptor kinase inhibitor that is well-tolerated with an acceptable safety profile that has shown efficacy against multiple types of cancer. The TGF-β ligand traps Bintrafusp alfa (a bifunctional conjugate that binds TGF-β and PD-L1), AVID200 (a computationally designed trap of TGF-β receptor ectodomains fused to an Fc domain) and Luspatercept (a recombinant fusion that links the activin receptor IIb to IgG) offer new ways to fight difficult-to-treat cancers. While TGF-β pathway antagonists are rapidly emerging as highly promising, safe and effective anticancer agents, significant challenges remain. Minimizing the unintentional inhibition of tumor-suppressing activity and inflammatory effects with the desired restraint on tumor-promoting activities has impeded the clinical development of TGF-β pathway antagonists. A better understanding of the mechanistic details of the TGF-β pathway should lead to more effective TGF-β antagonists and uncover biomarkers that better stratify patient selection, improve patient responses and further the clinical development of TGF-β antagonists.

Enhanced Intestinal TGF-β/SMAD-Dependent Signaling in Simian Immunodeficiency Virus Infected Rhesus Macaques

Transforming growth factor-β signaling (TGF-β) maintains a balanced physiological function including cell growth, differentiation, and proliferation and regulation of immune system by modulating either SMAD2/3 and SMAD7 (SMAD-dependent) or SMAD-independent signaling pathways under normal conditions. Increased production of TGF-β promotes immunosuppression in Human Immunodeficiency Virus (HIV)/Simian Immunodeficiency Virus (SIV) infection. However, the cellular source and downstream events of increased TGF-β production that attributes to its pathological manifestations remain unknown. Here, we have shown increased production of TGF-β in a majority of intestinal CD3⁻CD20⁻CD68⁺ cells from acute and chronically SIV infected rhesus macaques, which negatively correlated with the frequency of jejunum CD4⁺ T cells. No significant changes in intestinal TGF-β receptor II expression were observed but increased production of the pSMAD2/3 protein and SMAD3 gene expression in jejunum tissues that were accompanied by a downregulation of SMAD7 protein and gene expression. Enhanced TGF-β production by intestinal CD3⁻CD20⁻CD68⁺ cells and increased TGF-β/SMAD-dependent signaling might be due to a disruption of a negative feedback loop mediated by SMAD7. This suggests that SIV infection impacts the SMAD-dependent signaling pathway of TGF-β and provides a potential framework for further study to understand the role of viral factor(s) in modulating TGF-β production and downregulating SMAD7 expression in SIV. Regulation of mucosal TGF-β expression by therapeutic TGF-β blockers may help to create effective antiviral mucosal immune responses.

CD34+ Stromal Cells/Telocytes as a Source of Cancer-Associated Fibroblasts (CAFs) in Invasive Lobular Carcinoma of the Breast

Several origins have been proposed for cancer-associated fibroblasts (CAFs), including resident CD34+ stromal cells/telocytes (CD34+SCs/TCs). The characteristics and arrangement of mammary CD34+SCs/TCs are well known and invasive lobular carcinoma of the breast (ILC) is one of the few malignant epithelial tumours with stromal cells that can express CD34 or αSMA, which could facilitate tracking these cells. Our objective is to assess whether tissue-resident CD34+SCs/TCs participate in the origin of CAFs in ILCs. For this purpose, using conventional and immunohistochemical procedures, we studied stromal cells in ILCs (n:42) and in normal breasts (n:6, also using electron microscopy). The results showed (a) the presence of anti-CD34+ or anti-αSMA+ stromal cells in varying proportion (from very rare in one of the markers to balanced) around nests/strands of neoplastic cells, (b) a similar arrangement and location of stromal cells in ILC to CD34+SCs/TCs in the normal breast, (c) both types of stromal cells coinciding around the same nest of neoplastic cells and (d) the coexpression of CD34 and αSMA in stromal cells in ILC. In conclusion, our findings support the hypothesis that resident CD34+SCs/TCs participate as an important source of CAFs in ILC. Further studies are required in this regard in other tumours.

Prognostic Value of PLXND1 and TGF-β1 Coexpression and Its Correlation With Immune Infiltrates in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the most common primary liver malignancy with no curative treatments. Plexin D1 (PLXND1) is a cellular receptor whose functions have been explored in several human cancers; however, the critical roles of PLXND1 in HCC have rarely been probed. Therefore, the present study attempted to elucidate the expression pattern, prognostic significance, and potential roles of PLXND1 in HCC. We found that PLXND1 expression in HCC tissues was significantly higher compared with normal liver tissue from Gene Expression Profiling Interactive Analysis (GEPIA) and Integrative Molecular Database of Hepatocellular Carcinoma (HCCDB) databases. This result was further validated by immunohistochemistry staining (IHC) using tissue microarrays, which contained 216 HCC cases collected from our hospital. Additionally, PLXND1 expression showed a significant correlation with several clinical characteristics, including tumor grade and tumor hemorrhage (TH). Moreover, TISIDB and GEPIA databases were used to investigate the roles of PLXND1 in tumor-immune system interactions in HCC. As an immunoinhibitor, transforming growth factor-beta (TGF-β1) displayed the greatest correlations with PLXND1 in HCC. Finally, Kaplan-Meier curves and Cox analysis were conducted to further examine the potential clinical value of PLXND1 in HCC. We described a subclassification of HCC based on PLXND1 and TGF-β1 expression, which could be used to predict clinical outcomes and patient prognosis. Taken together, the results of this study indicate that PLXND1 might be a promising prognostic biomarker and potential therapeutic target in HCC.

A novel TGF-β receptor II mutation (I227T/N236D) promotes aggressive phenotype of oral squamous cell carcinoma via enhanced EGFR signaling

Background

Transforming growth factor-β (TGF-β) signaling is a double-edged sword in cancer development and progression. TGF-β signaling plays a tumor suppressive role during the early stages of tumor development but promotes tumor progression in later stages. We have previously identified various mutations of TGF-β receptor II (TβRII) in human oral squamous cell carcinoma (OSCC) samples. In the present study we analyzed I227T/N236D mutation of TβRII, which was detected in the metastatic lymph node of an OSCC patient.

Methods

The effect of I227T/N236D TβRII mutation on transcriptional activities was measured using DR26 cells, which lack functional TβRII. HSC2 human OSCC cells stably expressing wild-type and I227T/N236D mutant TβRII were generated and used to examine the effect of I227T/N236D TβRII mutation on xenograft tumor growth, in vitro cell proliferation, apoptosis, migration, and invasion.

Results

The I227T/N236D mutation of TβRII upregulated TGF-β signaling and promoted xenograft tumor growth when compared with the wild-type, without affecting the in vitro proliferative capacities. To delineate the differences in proliferative capacities in vivo and in vitro, the apoptotic and survival signals were analyzed following curcumin treatment. Concomitant with apoptotic induction, epidermal growth factor receptor (EGFR) activation was observed upon curcumin treatment, which was further activated in I227T/N236D mutant transfectant cells when compared with wild-type cells. Enhanced EGFR activation correlated with cell survival and apoptotic resistance. Enhanced migratory and invasive capabilities of I227T/N236D mutant cells also depended on EGFR signaling.

Conclusions

These results suggest that enhanced EGFR signaling via upregulated TGF-β signaling shifted the balance toward survival and promoted cell migration and invasion in I227T/N236D mutant cells, elucidating the role of I227T/N236D mutation of TβRII in OSCC progression.

The Small GTPase RAC1B: A Potent Negative Regulator of-and Useful Tool to Study-TGFβ Signaling

RAC1 and its alternatively spliced isoform, RAC1B, are members of the Rho family of GTPases. Both isoforms are involved in the regulation of actin cytoskeleton remodeling, cell motility, cell proliferation, and epithelial-mesenchymal transition (EMT). Compared to RAC1, RAC1B exhibits a number of distinctive features with respect to tissue distribution, downstream signaling and a role in disease conditions like inflammation and cancer. The subcellular locations and interaction partners of RAC1 and RAC1B vary depending on their activation state, which makes RAC1 and RAC1B ideal candidates to establish cross-talk with cancer-associated signaling pathways-for instance, interactions with signaling by transforming growth factor β (TGFβ), a known tumor promoter. Although RAC1 has been found to promote TGFβ-driven tumor progression, recent observations in pancreatic carcinoma cells surprisingly revealed that RAC1B confers anti-oncogenic properties, i.e., through inhibiting TGFβ-induced EMT. Since then, an unexpected array of mechanisms through which RAC1B cross-talks with TGFβ signaling has been demonstrated. However, rather than being uniformly inhibitory, RAC1B interacts with TGFβ signaling in a way that results in the selective blockade of tumor-promoting pathways, while concomitantly allowing tumor-suppressive pathways to proceed. In this review article, we are going to discuss the specific interactions between RAC1B and TGFβ signaling, which occur at multiple levels and include various components such as ligands, receptors, cytosolic mediators, transcription factors, and extracellular inhibitors of TGFβ ligands.

NEAT1/miR-200b-3p/SMAD2 axis promotes progression of melanoma

Melanoma is a skin malignancy with a high mutation frequency of genetic alterations. MicroRNA (miR)-200b-3p is involved in various cancers, while in melanoma its bio-function remains unknown. In this study, we found that miR-200b-3p was down-regulated in melanoma tissues and cell lines compared to benign nevus cells. Overexpression of miR-200b-3p significantly inhibited the proliferation and invasion of melanoma cells. According to bioinformatics analysis and sequencing data, we supposed that SMAD family member 2 (SMAD2) was the target gene and nuclear enriched abundant transcript 1 (NEAT1) was the upstream long non-coding RNA (lncRNA) of miR-200b-3p. These predictions were verified by western blotting and quantitative real-time reverse transcription PCR (RT-qPCR). Luciferase reporter assays revealed that NEAT1 up-regulated SMAD2 by directly sponging miR-200b-3p. In vitro and in vivo, we demonstrated that both NEAT1 and SMAD2 could promote the proliferation and invasion of melanoma cells, and these effects were reversed by up-regulating miR-200b-3p. In addition, NEAT1/miR-200b-3p/SMAD2 axis promoted melanoma progression by activating EMT signaling pathway and immune responses. Taken together, the NEAT1/miR-200b-3p/SMAD2 signaling pathway promotes melanoma via activation of EMT, cell invasion and is related with immune responses, which provides new insights into the molecular mechanisms and therapeutic targets for melanoma.

ATXN7L3 positively regulates SMAD7 transcription in hepatocellular carcinoma with growth inhibitory function

Background

Hepatocellular carcinoma (HCC) is a leading cause of cancer death worldwide, with unmet need for the pharmacological therapy. The functions of ATXN7L3 in HCC progression are not known.

Methods

RNA sequence, quantitative real-time PCR, and western blot were performed to detect gene expression. Chromatin immunoprecipitation was performed to detect possible mechanisms. Immunohistochemical stain was performed to examine the protein expression. Colony formation, cell growth curve and xenograft tumor experiments were performed to examine cell growth in vitro and in vivo.

Findings

ATXN7L3 functions as a coactivator for ERα-mediated transactivation in HCC cells, thereby contributing to enhanced SMAD7 transcription. ATXN7L3 is recruited to the promoter regions of SMAD7 gene, thereby regulating histone H2B ubiquitination level, to enhance the transcription of SMAD7. A series of genes regulated by ATXN7L3 were identified. Moreover, ATXN7L3 participates in suppression of tumor growth. In addition, ATXN7L3 is lower expressed in HCC samples, and the lower expression of ATXN7L3 positively correlates with poor clinical outcome in patients with HCC.

Interpretation

This study demonstrated that ATXN7L3 is a novel regulator of SMAD7 transcription, subsequently participating in inhibition of tumor growth in HCC, which provides an insight to support a previously unknown role of ATXN7L3 in HCC progression.

Fund

This work was funded by 973 Program Grant from the Ministry of Science and Technology of China (2013CB945201), National Natural Science Foundation of China (31871286, 81872015, 31701102, 81702800, 81902889), Foundation for Special Professor of Liaoning Province, Natural Science Foundation of Liaoning Province (No.20180530072); China Postdoctoral Science Foundation (2019M651164).

Effect of Kangquan Recipe () on BAMBI Expression in Hypothalamic-Pituitary-Prostate in Rats with Benign Prostatic Hyperplasia

OBJECTIVE

To investigate the effect of Kangquan Recipe (, KQR) on bone morphogenetic protein and activin membrane-bound inhibitor (BAMBI) expression and its mechanism in rats with benign prostatic hyperplasia (BPH).

METHODS

Forty-eight male Sprague-Dawley rats were divided into 6 groups using a random number table, with 8 in each group: the normal group (normal saline 10 mL/kg), the model group (normal saline 10 mL/kg), the finasteride group (0.5 mg/kg), the low-dose KQR group (3.5 g/kg), the middle-dose KQR group (7 g/kg), and the high-dose KQR group (14 g/kg). The 40 rats were subcutaneously injected with testosterone propionate after castration for 30 days to establish the BPH rat model except for those in the normal group. At the same time, the corresponding drugs were administered by gavage for 30 consecutive days. The effects of different doses of KQR on the protate wet weight, prostate volume and prostate index (PI) were observed. The changes in histopathology were monitored with hematoxylin-eosin staining. BAMBI protein and mRNA expression contents were determined by Western blot and quantitative real-time polymerase chain reaction, respectively.

RESULTS

All doses of KQR could decrease prostatic epithelial tissue proliferation. Compared to the model group, the high and middle-dose KQR significantly reduced prostate wet weight, prostate volume and PI; increased BAMBI protein expression in the hypothalamus, pituitary and prostate tissue; all doses of KQR up-regulated BAMBI mRNA expression in serum, prostatic fluid and prostate tissue (P<0.05 or P<0.01).

CONCLUSIONS

KQR could inhibit the proliferation of rat prostatic tissue, promote BAMBI protein expression in the hypothalamic-pituitary-prostate of rats with BPH; and increase BAMBI mRNA expression in the blood, prostatic fluid and prostate tissue of rats with BPH, showing a dose-effect relationship. KQR can be used as a potential drug for the treatment of BPH.

The effect of bone marrow mesenchymal stem cells on highly metastatic MHCC97-H hepatocellular carcinoma cells following OPN and TGFβ1 gene silencing

The metastatic behavior of hepatocellular carcinoma (HCC) is one of the key factors that leads to poor prognosis. The aim of the current study was to determine the changes in metastasis and the proliferation potential of bone marrow mesenchymal stem cells (BMSCs) in high metastatic potential hepatocellular carcinoma (MHCC97-H) following gene silencing. The osteopontin (OPN) and transforming growth factor-β (TGFβ₁ ) genes, which are associated with metastasis and tumor proliferation, were silenced in MHCC97-H cells. Transwell assays were used to evaluate the migration of MHCC97-H cells in vitro. Additionally, a murine model of MHCC97-H lung metastasis was established. Following OPN and TGFβ₁ silencing, the migration of MHCC97-H cells was significantly reduced following BMSC intervention (P<0.01). Furthermore, there were few MHCC97-H cells in the lung tissues of the OPN- and TGFβ₁ -silenced animals, and their integrated optical density (IOD) value was significantly lower compared with controls (P<0.05). Immunofluorescence of lung metastasis in the MHCC97-H model revealed that there was no significant difference in the IOD value of integrin α_vβ₃ expression in the OPN- and TGFβ₁ -silenced groups compared with controls (P>0.05). The metastasis and proliferation potential of MHCC97-H following BMSC intervention were significantly reduced in vitro and in vivo, especially in the TGFβ₁-silenced group. The decrease in the metastatic potential in gene-silenced MHCC97-H cells was not associated with integrin α_vβ₃ expression. Therefore, OPN and TGFβ₁ may be potential targets for HCC treatment, and TGFβ₁ may have a higher therapeutic potential for BMSC intervention.

Mechanism of TGF-β1 inhibiting Kupffer cell immune responses in cholestatic cirrhosis

Effect of exogenous transforming growth factor-β1 (TGF-β1) on cholestatic mice by inhibiting Kupffer cell immune responses in liver was investigated. To induce cholestasis, BALB/c mice received a sham operation (Mock group), or underwent a bile duct ligation (BDL group) and then were subcutaneously injected with TGF-β1 at multiple sites (TGF group). Liver functions were evaluated according to the levels of alanine aminotransferase (ALT), aspartate aminotransferase AST and γ-glutamyltranspeptidase (γ-GT) in serum samples. Expression of nuclear factor-κB (NF-κB), interleukin-6 (IL-6), IL-1β and tumor necrosis factor-α (TNF-α) was detected. Expression of inducible nitric oxide synthase (iNOS) and arginase-1 (Arg-1) in Kupffer cells (KCs) of the liver was detected. The isolated KCs were divided into control group, LPS group, TGF group and Galunisertib group and western blot analysis was used to detect the expression of NF-κB, IL-6, IL-1β, TNF-α, iNOS and Arg-1. The percentage of CD40, CD86, CD204 and CD206 as macrophage cell surface antigens were measured by flow cytometry. The indexes of liver function and liver fibrosis of the mice in the TGF group were significantly lower than those in the BDL group (P<0.05). The levels of IL-1β, IL-6 and TNF-α in the liver were lower than those in the BDL group, while the level of IL-10 was significantly increased (P<0.05). M2-type transformation occurred in liver Kupffer cells of mice in the TGF group. In cell experiments, TGF treatment downregulated the expression of IL-1β, IL-6, TNF-α and NF-κB, increased the expression of IL-10, and induced M2-type transformation in macrophages (P<0.05). In conclusion, TGF-ß1 diminished the progression of cholestasis in mice by inhibiting the inflammatory response of KCs and regulating KC polarization.

An In Vitro Model of Mast Cell Recruitment and Activation by Breast Cancer Cells Supports Anti-Tumoral Responses

Breast cancer (BrC) affects millions of women yearly. Mast cells (MCs) are common components of breast tumors with documented agonistic and antagonistic roles in tumor progression. Understanding the participation of MCs in BrC may lead to new therapies to control tumor growth. In this study, we looked into mechanistic models of MC responses triggered by BrC cells (BrCC), assessing both early degranulation and late transcriptional activities. We used aggressive and non-aggressive BrCC to model the progressive staging of the disease over HMC1 and LAD-2 human MC lines. We found that both MC lines were chemoattracted by all BrCC, but their activation was preferentially induced by aggressive lines, finding differences in their active transcriptional programs, both at basal level and after stimulation. Among those genes with altered expression were down-regulated SPP1, PDCD1, IL17A and TGFB1 and up-regulated KITLG and IFNG. A low expression of SPP1 and a high expression of KITLG and IFNG were associated with increased overall survival of BrC patients from public databases. The set of altered genes is more often associated with tumor stromas enriched with anti-tumoral signals, suggesting that MCs may participate in tumor control.

RAC1B Induces SMAD7 via USP26 to Suppress TGFβ1-Dependent Cell Migration in Mesenchymal-Subtype Carcinoma Cells

The small GTPase RAC1B has been shown to act as a powerful inhibitor of the transforming growth factor (TGF)β type I receptor ALK5 and TGFβ1/ALK5-induced epithelial–mesenchymal transition and cell motility. However, the precise mechanism has remained elusive. RNAi-mediated knockdown of RAC1B in the pancreatic ductal adenocarcinoma (PDAC)-derived cell line Panc1 failed to alter transcriptional activity from a transfected ALK5 promoter–reporter construct. In contrast, pharmacological inhibition of the proteasome decreased the abundance of ALK5 protein in cell lines of the mesenchymal subtype (Panc1, IMIM-PC-1, and breast cancer MDA-MB-231), but not in a PDAC cell line of the epithelial subtype (Colo357). Here, we focused on the inhibitory Smad protein, SMAD7, as a potential candidate for RAC1B-mediated inhibition of cell migration. In Panc1 cells devoid of RAC1B, SMAD7 protein was dramatically reduced and these cells were refractory to TGFβ1-induced upregulation of SMAD7 protein but not mRNA expression. Intriguingly, RNAi-mediated knockdown or ectopic overexpression of SMAD7 in Panc1 cells up- or downregulated, respectively, ALK5 protein expression and mimicked the suppressive effect of RAC1B on TGFβ/SMAD3-dependent transcriptional activity, target gene expression and cell migration. Transfection of SMAD7 was further able to partially rescue cells from the RAC1B knockdown-mediated increase in migratory properties. Conversely, knockdown of SMAD7 was able to partially rescue Panc1 and MDA-MB-231 cells from the antimigratory effect of ectopically expressed RAC1B. Finally, we demonstrate that RAC1B upregulation of SMAD7 protein requires intermittent transcriptional induction of the deubiquitinating enzyme USP26. Our data suggest that RAC1B induces SMAD7 by promoting its deubiquitination and establishes this Smad as one of RAC1B’s downstream effectors in negative regulation of ALK5 and TGFβ1-induced cell migration in mesenchymal-type carcinoma cells.

Metformin and Vascular Diseases: A Focused Review on Smooth Muscle Cell Function

Metformin has been used in diabetes for more than 60 years and has excellent safety in the therapy of human type 2 diabetes (T2D). There is growing evidence that the beneficial health effects of metformin are beyond its ability to improve glucose metabolism. Metformin not only reduces the incidence of cardiovascular diseases (CVD) in T2D patients, but also reduces the burden of atherosclerosis (AS) in pre-diabetes patients. Vascular smooth muscle cells (VSMCs) function is an important factor in determining the characteristics of the entire arterial vessel. Its excessive proliferation contributes to the etiology of several types of CVD, including AS, restenosis, and pulmonary hypertension. Current studies show that metformin has a beneficial effect on VSMCs function. Therefore, this review provides a timely overview of the role and molecular mechanisms by which metformin acts through VSMCs to protect CVD.

Clonorchis sinensis ESPs enhance the activation of hepatic stellate cells by a cross-talk of TLR4 and TGF-β/Smads signaling pathway

Excretory/Secretory products (ESPs) from Clonorchis sinensis-a fluke dwelling on the biliary ducts-promote the activation of hepatic stellate cells (HSCs) and lead to hepatic fibrosis ultimately, although the mechanisms that are responsible for CsESPs-induced activation of HSCs are largely unknown. In the present study, we investigated the underlying mechanism of TLR4 in the regulation of the activation of HSCs caused by CsESPs. We found that the expression of TLR4 was significantly increased in the HSCs with CsESPs for 24 h, compared to the control group. However, the activation of HSCs induced by CsESPs was inhibited by interfering with TGF-β/Smad pathway using a TGF-β receptor I inhibitor LY2157299, indicating that TGF-β induced signaling pathway was involved in CsESPs-caused the activation of HSCs. In addition, the activation of HSCs caused by CsESPs was remarkably inhibited by a TLR4 specific inhibitor (VIPER), and phosphorylation of Smad2/3 was significantly attenuated but the expression of the pseudoreceptor of TGF-β-type I receptor (BAMBI) was obviously increased when TLR4 signaling pathway was blocked. The results of the present study demonstrate that activation of HSCs caused by CsESPs is mediated by a cross-talk between TLR4 and TGF-β/Smads signaling pathway, and may provide a potential treatment strategy to interrupt the process of liver fibrosis caused by C. sinensis.

Prognostic Values of Transforming Growth Factor-Beta Subtypes in Ovarian Cancer

PURPOSE

To explore the potential role of the transforming growth factor-beta (TGF-β) subtypes in the prognosis of ovarian cancer patients. Materials and Methods. The prognostic roles of individual TGF-β subtypes in women with ovarian cancer were retrieved from the Kaplan-Meier plotter (KM plotter) database. In addition, the Oncomine database and immunohistochemistry were used to observe the mRNA and protein expression of TGF-β subtypes between human ovarian carcinoma and normal ovarian samples, respectively.

RESULTS

TGF-β1 and TGF-β4 were totally uncorrelated with survival outcomes in women with ovarian cancer. Increased TGF-β2 and TGF-β3 mRNA expression was markedly related to unfavorable prognosis, especially in women with serous, poorly differentiated, and late-stage ovarian carcinoma. High expression levels of TGF-β2 were related to worse progression-free survival (PFS) while TGF-β3 was linked to unfavorable overall survival (OS) and PFS in women with TP53-mutated ovarian cancer. TGF-β2 was associated with poor OS and PFS from treatment with chemotherapy with platins, Taxol, or a platin+Taxol. However, overexpression of TGF-β3 was associated with poor OS from the use of platins and poor PFS of Taxol or a platin+Taxol in women with ovarian carcinoma. Furthermore, the expression of TGF-β2 mRNA and protein was higher but only TGF-β3 mRNA expression was higher in cancerous tissues than in normal ovarian samples.

CONCLUSION

Higher expression of TGF-β2 functioned as a significant predictor of poor prognosis in women with ovarian cancer, especially those with TP53 mutations or who were undergoing chemotherapy with platins, Taxol, or a platin+Taxol.

Retinol dehydrogenase 10 promotes metastasis of glioma cells via the transforming growth factor-β/SMAD signaling pathway

Background:

Glioma is the most common primary malignant tumor in the central nervous system. Because of the resistance of glioma to chemoradiotherapy and its aggressive growth, the survival rate of patients with glioma has not improved. This study aimed to disclose the effect of retinol dehydrogenase 10 (RDH10) on the migration and invasion of glioma cells, and to explore the potential mechanism.

Methods:

Reverse transcription-polymerase chain reaction (RT-PCR) was used to determine the expression levels of RDH10 in healthy glial cells and glioma cells. Human glioma cell strains, U87 and U251, were infected with negative control or RDH10-interfering lentiviruses. RT-PCR and Western blotting were performed to determine the knockdown efficiency. Scratch and transwell assays were used to assess cell migration and invasion after RDH10 knockdown. Finally, changes in transforming growth factor-β (TGF-β)/SMAD signaling pathway-related expression were examined by Western blotting. Differences between groups were analyzed by one-way analysis of variance.

Results:

RDH10 was highly expressed in glioma cells. Compared with the control group, RDH10 knockdown significantly reduced RDH10 messenger RNA and protein expression levels in U87 and U251 glioma cells (U87: 1.00 ± 0.08 vs. 0.22 ± 0.02, t = 16.55, P < 0.001; U251: 1.00 ± 0.17 vs. 0.39 ± 0.01, t = 6.30, P < 0.001). The scratch assay indicated that compared with the control group, RDH10 knockdown significantly inhibited the migration of glioma cells (U87: 1.00% ± 0.04% vs. 2.00% ± 0.25%, t = 6.08, P < 0.01; U251: 1.00% ± 0.11% vs. 2.48% ± 0.31%, t = 5.79, P < 0.01). Furthermore, RDH10 knockdown significantly inhibited the invasive capacity of glioma cells (U87: 97.30 ± 7.01 vs. 13.70 ± 0.58, t = 20.36, P < 0.001; U251: 96.20 ± 7.10 vs. 18.30 ± 2.08, t = 18.51, P < 0.001). Finally, Western blotting demonstrated that compared with the control group, downregulation of RDH10 significantly inhibited TGF-β expression, phosphorylated SMAD2, and phosphorylated SMAD3 (TGF-β: 1.00 ± 0.10 vs. 0.53 ± 0.06, t = 7.05, P < 0.01; phosphorylated SMAD2: 1.00 ± 0.20 vs. 0.42 ± 0.17, t = 4.01, P < 0.01; phosphorylated SMAD3: 1.00 ± 0.18 vs. 0.41 ± 0.12, t = 4.12, P < 0.01).

Conclusion:

RDH10 knockdown might inhibit metastasis of glioma cells via the TGF-β/SMAD signaling pathway.

Protein phosphatase Mg2+ /Mn2+ dependent-1A and PTEN deregulation in renal fibrosis: Novel mechanisms and co-dependency of expression

PPM1A and PTEN emerged as novel suppressors of chronic kidney disease (CKD). Since loss of PPM1A and PTEN in the tubulointerstitium promotes fibrogenesis, defining molecular events underlying PPM1A/PTEN deregulation is necessary to develop expression rescue as novel therapeutic strategies. Here we identify TGF-β1 as a principle repressor of PPM1A, as conditional renal tubular-specific induction of TGF-β1 in mice dramatically downregulates kidney PPM1A expression. TGF-β1 similarly attenuates PPM1A and PTEN expression in human renal epithelial cells and fibroblasts, via a protein degradation mechanism by promoting their ubiquitination. A proteasome inhibitor MG132 rescues PPM1A and PTEN expression, even in the presence of TGF-β1, along with decreased fibrogenesis. Restoration of PPM1A or PTEN similarly limits SMAD3 phosphorylation and the activation of TGF-β1-induced fibrotic genes. Concurrent loss of PPM1A and PTEN levels in aristolochic acid nephropathy further suggests crosstalk between these repressors. PPM1A silencing in renal fibroblasts, moreover, results in PTEN loss, while PTEN stable depletion decreases PPM1A expression with acquisition of a fibroproliferative phenotype in each case. Transient PPM1A expression, conversely, elevates cellular PTEN levels while lentiviral PTEN introduction increases PPM1A expression. PPM1A and PTEN, therefore, co-regulate each other's relative abundance, identifying a previously unknown pathological link between TGF-β1 repressors, contributing to CKD.

TGFβ Family Signaling Pathways in Pluripotent and Teratocarcinoma Stem Cells' Fate Decisions: Balancing Between Self-Renewal, Differentiation, and Cancer

The transforming growth factor-β (TGFβ) family factors induce pleiotropic effects and are involved in the regulation of most normal and pathological cellular processes. The activity of different branches of the TGFβ family signaling pathways and their interplay with other signaling pathways govern the fine regulation of the self-renewal, differentiation onset and specialization of pluripotent stem cells in various cell derivatives. TGFβ family signaling pathways play a pivotal role in balancing basic cellular processes in pluripotent stem cells and their derivatives, although disturbances in their genome integrity induce the rearrangements of signaling pathways and lead to functional impairments and malignant transformation into cancer stem cells. Therefore, the identification of critical nodes and targets in the regulatory cascades of TGFβ family factors and other signaling pathways, and analysis of the rearrangements of the signal regulatory network during stem cell state transitions and interconversions, are key issues for understanding the fundamental mechanisms of both stem cell biology and cancer initiation and progression, as well as for clinical applications. This review summarizes recent advances in our understanding of TGFβ family functions in naїve and primed pluripotent stem cells and discusses how these pathways are involved in perturbations in the signaling network of malignant teratocarcinoma stem cells with impaired differentiation potential.

Prognostic Implication of pAMPK Immunohistochemical Staining by Subcellular Location and Its Association with SMAD Protein Expression in Clear Cell Renal Cell Carcinoma

Although cytoplasmic AMP-activated protein kinase (AMPK) has been known as a tumor-suppressor protein, nuclear AMPK is suggested to support clear cell renal cell carcinoma (ccRCC). In addition, pAMPK interacts with TGF-β/SMAD, which is one of the frequently altered pathways in ccRCC. In this study, we investigated the prognostic significance of pAMPK with respect to subcellular location and investigated its interaction with TGF-β/SMAD in ccRCC. Immunohistochemical staining for pAMPK, pSMAD2 and SMAD4 was conducted on tissue microarray of 987 ccRCC specimens. Moreover, the levels of pSMAD2 were measured in Caki-1 cells treated with 5-aminoimidazole-4-carboxamide ribonucleotide. The relationship between AMPK/pAMPK and TGFB1 expression was determined using the TCGA database. As a result, pAMPK positivity, either in the cytoplasm or nuclei, was independently associated with improved ccRCC prognosis, after adjusting for TNM stage and WHO grade. Furthermore, pAMPK-positive ccRCC displayed increased pSMAD2 and SMAD4 expression, while activation of pAMPK increased pSMAD2 in Caki-1 cells. However, AMPK/pAMPK expression was inversely correlated with TGFB1 expression in the TCGA database. Therefore, pAMPK immunostaining, both in the cytoplasm and nuclei, is a useful prognostic biomarker for ccRCC. pAMPK targets TGF-β-independent phosphorylation of SMAD2 and activates pSMAD2/SMAD4, representing a novel anti-tumoral mechanism of pAMPK in ccRCC.

Downregulation of circRNA DMNT3B contributes to diabetic retinal vascular dysfunction through targeting miR-20b-5p and BAMBI

Background

Diabetic retinopathy, a vascular complication of diabetes mellitus, is the leading cause of visual impairment and blindness. circRNAs act as competing endogenous RNA, sponging target miRNA and thus influencing mRNA expression in vascular diseases. We investigated whether and how circDNMT3B is involved in retinal vascular dysfunction under diabetic conditions.

Methods

qRT-PCR was performed to detect expression of circDNMT3B, miR-20b-5p, and BAMBI in retinal microvascular endothelial cells under diabetic conditions. Western blot, Cell Counting Kit-8, Transwell, Matrigel tube formation, and retinal trypsin digestion assays were conducted to explore the roles of circDNMT3B/miR-20b-5p/BAMBI in retinal vascular dysfunction. Bioinformatics analysis and luciferase reporter, siRNA, and overexpression assays were used to reveal the mechanisms of the circDNMT3B/miR-20b-5p/BAMBI interaction. Electroretinograms were used to evaluate visual function.

Findings

Upregulation of miR-20b-5p under diabetic conditions promoted proliferation, migration, and tube formation of human retinal microvascular endothelial cells (HRMECs), which was mediated by downregulated BAMBI. Under diabetic conditions, circDNMT3B, which acts as a sponge of miR-20b-5p, is downregulated. circDNMT3B overexpression reduced retinal acellular capillary number and alleviated visual damage in diabetic rats. Changes in expression of circDNMT3B and miR-20b-5p were confirmed in the proliferative fibrovascular membranes of patients with diabetic retinopathy.

Interpretation

Downregulation of circDNMT3B contributes to vascular dysfunction in diabetic retinas through regulating miR-20b-5p and BAMBI, providing a potential treatment strategy for diabetic retinopathy.

Funding

National Natural Science Foundation of China, National Key Basic Research Program of China, Shanghai Municipal Science and Technology Major Project, and ZJLab.