Curcumin inhibits transforming growth factor-β1-induced EMT via PPARγ pathway, not Smad pathway in renal tubular epithelial cells

Partial Activation of PPAR-γ by Synthesized Quercetin Derivatives Modulates TGF-β1-Induced EMT in Lung Cancer Cells

Non-small cell lung cancer (NSCLC) has a very low survival rate due to poor response to chemotherapy and late detection. Epithelial to mesenchymal transition (EMT) is regarded as a major contributor to drive metastasis during NSCLC progression. Towards this, transforming growth factor-beta 1 (TGF-β1) is the key driver that endows cancer cells with increased aggressiveness. Recently, this group synthesized a series of Schiff base quercetin derivatives (QDs) and ascertained their effectiveness on EMT markers of A549 cell line. This study evidenced that the EMT process is counteracted via the partial activation of a nuclear hormone receptor, Peroxisome proliferator-activated receptor (PPAR)-γ through QDs. Here, that work is extended to investigate the interplay between PPAR-γ partial activation and TGF-β1-induced EMT in human lung cancer A549 cells. The results reveal that TGF-β1 plays a critical role in suppressing PPAR-γ, which is markedly reversed and increased by partial agonists: QUE2FH and QUESH at both protein and transcriptional levels. The partial agonists not only stimulate PPAR-γ in a balanced manner but also prevent the loss of E-cadherin and acquisition of TGF-β1-induced mesenchymal markers (Snail, Slug, Vimentin, and Zeb-1). Subsequently, the effects are accompanied by attenuation of TGF-β1-induced migratory ability of A549 cells.

Design, Synthesis, and Biological Evaluation of Novel Quercetin Derivatives as PPAR-γ Partial Agonists by Modulating Epithelial-Mesenchymal Transition in Lung Cancer Metastasis

Epithelial-to-mesenchymal transition (EMT) is responsible for driving metastasis of multiple cancer types including lung cancer. Peroxisome proliferator-activated receptor (PPAR)-γ, a ligand-activated transcription factor, controls expression of variety of genes involved in EMT. Although several synthetic compounds act as potent full agonists for PPAR-γ, their long term application is restricted due to serious adverse effects. Therefore, partial agonists involving reduced and balanced PPAR-γ activity are more effective and valued. A previous study discerned the efficacy of quercetin and its derivatives to attain favorable stabilization with PPAR-γ. Here this work is extended by synthesizing five novel quercetin derivatives (QDs) namely thiosemicarbazone (QUETSC)) and hydrazones (quercetin isonicotinic acid hydrazone (QUEINH), quercetin nicotinic acid hydrazone (QUENH), quercetin 2-furoic hydrazone (QUE2FH), and quercetin salicyl hydrazone (QUESH)) and their effects are analyzed in modulating EMT in lung cancer cell lines via PPAR-γ partial activation. QDs-treated A549 cells diminish cell proliferation strongly at nanomolar concentration compared to NCI-H460 cells. Of the five screened derivatives, QUETSC, QUE2FH, and QUESH exhibit the property of partial activation as compared to the overexpressive level of rosiglitazone. Consistently, these QDs also suppress EMT process by markedly downregulating the levels of mesenchymal markers (Snail, Slug, and zinc finger E-box binding homeobox 1) and concomitant upregulation of epithelial marker (E-cadherin).

The epithelial-mesenchymal plasticity landscape: principles of design and mechanisms of regulation

Epithelial-mesenchymal plasticity (EMP) enables cells to interconvert between several states across the epithelial-mesenchymal landscape, thereby acquiring hybrid epithelial/mesenchymal phenotypic features. This plasticity is crucial for embryonic development and wound healing, but also underlies the acquisition of several malignant traits during cancer progression. Recent research using systems biology and single-cell profiling methods has provided novel insights into the main forces that shape EMP, which include the microenvironment, lineage specification and cell identity, and the genome. Additionally, key roles have emerged for hysteresis (cell memory) and cellular noise, which can drive stochastic transitions between cell states. Here, we review these forces and the distinct but interwoven layers of regulatory control that stabilize EMP states or facilitate epithelial-mesenchymal transitions (EMTs) and discuss the therapeutic potential of manipulating the EMP landscape.

Antioxidant Activity in Extracts from Zingiberaceae Family: Cardamom, Turmeric, and Ginger

An increase in life expectancy leads to a greater impact of chronic non-communicable diseases. This is even more remarkable in elder populations, to whom these become main determinants of health status, affecting mental and physical health, quality of life, and autonomy. Disease appearance is closely related to the levels of cellular oxidation, pointing out the importance of including foods in one's diet that can prevent oxidative stress. Previous studies and clinical data suggest that some plant-based products can slow and reduce the cellular degradation associated with aging and age-related diseases. Many plants from one family present several applications that range from the food to the pharmaceutical industry due to their characteristic flavor and scents. The Zingiberaceae family, which includes cardamom, turmeric, and ginger, has bioactive compounds with antioxidant activities. They also have anti-inflammatory, antimicrobial, anticancer, and antiemetic activities and properties that help prevent cardiovascular and neurodegenerative diseases. These products are abundant sources of chemical substances, such as alkaloids, carbohydrates, proteins, phenolic acids, flavonoids, and diarylheptanoids. The main bioactive compounds found in this family (cardamom, turmeric, and ginger) are 1,8-cineole, α-terpinyl acetate, β-turmerone, and α-zingiberene. The present review gathers evidence surrounding the effects of dietary intake of extracts of the Zingiberaceae family and their underlying mechanisms of action. These extracts could be an adjuvant treatment for oxidative-stress-related pathologies. However, the bioavailability of these compounds needs to be optimized, and further research is needed to determine appropriate concentrations and their antioxidant effects in the body.

A systems biology investigation of curcumin potency against TGF-β-induced EMT signaling in lung cancer

Curcumin (diferuloylmethane) is bioactive phenolic compound which exerts diverse antimetastatic effect. Several studies have reported the antimetastatic effect of curcumin by its ability to modulate the epithelial-to-mesenchymal transition (EMT) process in different cancers, but underlying molecular mechanism is poorly understood. EMT is a highly conserved biological process in which epithelial cells acquire mesenchymal-like characteristics by losing their cell-cell junctions and polarity. As a consequence, deviation in cellular mechanism leads to cancer metastasis and thereby death. In this perspective, we explored the antimetastatic potential and mechanism of curcumin on the EMT process by establishing in vitro EMT model in lungs cancer (A549) cells induced by TGF-β1. Our results showed that curcumin mitigates EMT by regulating the expression of crucial mesenchymal markers such as MMP2, vimentin and N-cadherin. Besides, the transcriptional analysis revealed that the curcumin treatment differentially regulated the expression of 75 genes in NanoString nCounter platform. Further protein-protein interaction network and clusters analysis of differentially expressed genes revealed their involvement in essential biological processes that plays a key role during EMT transition. Altogether, the study provides a comprehensive overview of the antimetastatic potential of curcumin in TGF-β1-induced EMT in lung cancer cells.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13205-022-03360-7.

Overcoming therapeutic resistance to platinum-based drugs by targeting Epithelial–Mesenchymal transition

Platinum-based drugs (PBDs), including cisplatin, carboplatin, and oxaliplatin, have been widely used in clinical practice as mainstay treatments for various types of cancer. Although there is firm evidence of notable achievements with PBDs in the management of cancers, the acquisition of resistance to these agents is still a major challenge to efforts at cure. The introduction of the epithelial-mesenchymal transition (EMT) concept, a critical process during embryonic morphogenesis and carcinoma progression, has offered a mechanistic explanation for the phenotypic switch of cancer cells upon PBD exposure. Accumulating evidence has suggested that carcinoma cells can enter a resistant state via induction of the EMT. In this review, we discussed the underlying mechanism of PBD-induced EMT and the current understanding of its role in cancer drug resistance, with emphasis on how this novel knowledge can be exploited to overcome PBD resistance via EMT-targeted compounds, especially those under clinical trials.

In Silico Analysis and Comparative Molecular Docking Study of FDA Approved Drugs with Transforming Growth Factor Beta Receptors in Oral Submucous Fibrosis

Abstract

Oral sub-mucous fibrosis (OSMF) is a severe crippling malignant disorder which affects the oral mucosa. The transforming growth factor beta (TGF-β) is one of the cytokines involved with the cell proliferation, cell growth and apoptosis. Several traditional and synthetic medications have been tried in OSMF. This study attempts to identify the FDA approved drugs (including both synthetic and herbal medications) with least side effects, highest efficacy and robust dynamic mechanism for the treatment of OSMF. A ligand library comprising of FDA approved drug compounds was prepared using ChEMBL database. Molecular docking was carried out using GOLD suite 5.2.2. The docked complexes which had the highest binding affinities and lowest energy were deployed to a molecular dynamic simulation using MDweb server. Further, SwissADME  was used to study ADME, physicochemistry, drug-likeness, pharmacokinetics and medicinal chemistry friendliness properties. Our docking results suggest that ligands-Curcumin, Curcumin Pyrazole and Demethoxycurcumin, which are all herbal in nature, have a better binding affinity and the best docking scores for both TGF-β type I and TGF-β type II receptors. The molecular dynamics study discerns that the structures have become more stable with less energy. The pharmacokinetics and pharmacodynamics analysis, physicochemical properties and toxicity prediction suggest that Curcumin is the optimal lead compound and holds the potential to be used as an effective drug for the treatment of OSMF. Curcumin, a FDA approved herbal compound, can be used as an effective drug for the treatment of OSMF.

Graphic Abstract

Research Progress of Chinese Herbal Medicine Intervention in Renal Interstitial Fibrosis

Chronic kidney diseases usually cause renal interstitial fibrosis, the prevention, delay, and treatment of which is a global research hotspot. However, no definite treatment options are available in modern medicine. Chinese herbal medicine has a long history, rich varieties, and accurate treatment effects. Hitherto, many Chinese herbal medicine studies have emerged to improve renal interstitial fibrosis. This paper reviews the mechanisms of renal interstitial fibrosis and recent studies on the disease intervention with Chinese herbal medicine through literature search, intend to reveal the importance of Chinese herbal medicine in renal interstitial fibrosis. The results show that Chinese herbal medicine can improve renal interstitial fibrosis, and the effects of Chinese herbal medicine on specific pathological mechanisms underlying renal interstitial fibrosis have been explored. Additionally, the limitations and advantages of Chinese herbal medicine in the treatment of renal interstitial fibrosis, possible research directions, and new targets of Chinese herbal medicine are discussed to provide a basis for studies of renal interstitial fibrosis.

Pharmaceutical Prospects of Curcuminoids for the Remedy of COVID-19: Truth or Myth

Coronavirus disease 2019 (COVID-19) is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which is a positive-strand RNA virus, and has rapidly spread worldwide as a pandemic. The vaccines, repurposed drugs, and specific treatments have led to a surge of novel therapies and guidelines nowadays; however, the epidemic of COVID-19 is not yet fully combated and is still in a vital crisis. In repositioning drugs, natural products are gaining attention because of the large therapeutic window and potent antiviral, immunomodulatory, anti-inflammatory, and antioxidant properties. Of note, the predominant curcumoid extracted from turmeric (Curcuma longa L.) including phenolic curcumin influences multiple signaling pathways and has demonstrated to possess anti-inflammatory, antioxidant, antimicrobial, hypoglycemic, wound healing, chemopreventive, chemosensitizing, and radiosensitizing spectrums. In this review, all pieces of current information related to curcumin-used for the treatment and prevention of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection through in vitro, in vivo, and in silico studies, clinical trials, and new formulation designs are retrieved to re-evaluate the applications based on the pharmaceutical efficacy of clinical therapy and to provide deep insights into knowledge and strategy about the curcumin's role as an immune booster, inflammatory modulator, and therapeutic agent against COVID-19. Moreover, this study will also afford a favorable application or approach with evidence based on the drug discovery and development, pharmacology, functional foods, and nutraceuticals for effectively fighting the COVID-19 pandemic.

Curcumin Inhibits HGF-Induced EMT by Regulating c-MET-Dependent PI3K/Akt/mTOR Signaling Pathways in Meningioma

Meningiomas, which are the most common primary intracranial tumors, have highly aggressive cells in malignant cases. Due to its extensive antitumor effects, curcumin is widely used in experimental and clinical studies. However, the role of curcumin during the epithelial-mesenchymal transition (EMT) in meningioma has not been established. We found that curcumin blocks hepatocyte growth factor- (HGF-) induced proliferation, migration, invasion, and EMT of human malignant meningioma cells by regulating the PI3K/Akt/mTOR signaling pathway. In addition, treatment of human malignant meningioma cells with the tyrosine protein kinase (c-MET) inhibitor (SU11274) or the phosphoinositide 3-kinase (PI3K) inhibitor (LY294002) suppressed HGF-induced migration and EMT. Furthermore, we found that curcumin inhibited tumor growth and HGF-induced EMT in mice subjected to subcutaneous xenotransplantation. These findings indicate that HGF regulates EMT in human malignant meningioma cells through c-MET/PI3K/Akt/mTOR modulation. In conclusion, curcumin inhibits HGF-induced EMT by targeting c-MET and subsequently blocking the PI3K/Akt/mTOR pathway.

Curcumin attenuates renal interstitial fibrosis of obstructive nephropathy by suppressing epithelial-mesenchymal transition through inhibition of the TLR4/NF-кB and PI3K/AKT signalling pathways

CONTEXT

Renal interstitial fibrosis (RIF) is characterized by the accumulation of inflammatory cytokines and epithelial-mesenchymal transition (EMT). Curcumin exerts antifibrogenic, anti-inflammatory and antiproliferative effects.

OBJECTIVE

To explore the mechanisms underlying the effects of curcumin on RIF.

MATERIALS AND METHODS

Eight-week-old male C57BL/6 mice were intragastrically administered curcumin (50 mg/kg/day) for 14 days after undergoing unilateral ureteral obstruction (UUO) operations. Renal function (blood urea nitrogen [BUN] and serum creatinine [Scr]) and inflammatory cytokine levels were tested using colorimetric assays and ELISA, respectively. EMT markers were evaluated through immunohistochemistry, western blotting and qPCR. Transforming growth factor beta 1 (TGF-β1; 10 ng/mL) and lipopolysaccharides (LPS; 100 ng/mL) were used to stimulate EMT and an inflammatory response in human renal proximal tubular epithelial (HK-2) cells, respectively, for further investigation.

RESULTS

In vivo, curcumin significantly improved the levels of BUN and Scr by 28.7% and 21.3%, respectively. Moreover, curcumin reduced the levels of IL-6, IL-1β and TNF-α by 22.5%, 30.3% and 26.7%, respectively, and suppressed vimentin expression in UUO mice. In vitro, curcumin reduced the expression of vimentin and α-smooth muscle actin in TGF-β1-induced HK-2 cells. In LPS-induced HK-2 cells, curcumin decreased the release of IL-6, IL-1β and TNF-α by 43.4%, 38.1% and 28.3%, respectively. In addition, curcumin reduced the expression of TLR4, p-PI3K, p-AKT, p-NF- κB and p-IκBα in both LPS- and TGF-β1-induced HK-2 cells.

DISCUSSION AND CONCLUSIONS

Curcumin repressed EMT and the inflammatory response by inhibiting the TLR4/NF-κB and PI3K/AKT pathways, demonstrating its potential utility in RIF treatment.

Complementary therapies for patients with systemic sclerosis

Patients with systemic sclerosis often seek information regarding complementary and nutrition-based therapy. Some study results have shown that vitamins D and E, probiotics, turmeric, l-arginine, essential fatty acids, broccoli, biofeedback, and acupuncture may be beneficial in systemic sclerosis care. However, large randomized clinical trials have not been conducted. This review summarizes current data regarding various complementary therapies in systemic sclerosis and concludes with recommendations.

Traditional Chinese Medicine and regulatory roles on epithelial-mesenchymal transitions

Epithelial–mesenchymal transition (EMT) is a critical biological process allowing epithelial cells to de-differentiate into mesenchymal cells. Orchestrated signaling pathways cooperatively induce EMT and effect physiological, sometimes pathological outcomes. Traditional Chinese Medicine (TCM) has been clinically prescribed for thousands of years and recent studies have found that TCM therapies can participate in EMT regulation. In this review, the historical discovery of EMT will be introduced, followed by a brief overview of its major roles in development and diseases. The second section will focus on EMT in organ fibrosis and tissue regeneration. The third section discusses EMT-induced cancer metastasis, and details how EMT contribute to distant dissemination. Finally, new EMT players are described, namely microRNA, epigenetic modifications, and alternative splicing. TCM drugs that affect EMT proven through an evidence-based research approach will be presented in each section.

Dietary Curcumin: Correlation between Bioavailability and Health Potential

The yellow pigment curcumin, extracted from turmeric, is a renowned polyphenol with a broad spectrum of health properties such as antioxidant, anti-inflammatory, anti-cancer, antidiabetic, hepatoprotective, anti-allergic, anti-dermatophyte, and neuroprotective. However, these properties are followed by a poor pharmacokinetic profile which compromises its therapeutic potential. The association of low absorption by the small intestine and the extensive reductive and conjugative metabolism in the liver dramatically weakens the oral bioavailability. Several strategies such as inhibition of curcumin metabolism with adjuvants as well as novel solid and liquid oral delivery systems have been tried to counteract curcumin poor absorption and rapid elimination from the body. Some of these drug deliveries can successfully enhance the solubility, extending the residence in plasma, improving the pharmacokinetic profile and the cellular uptake.

β-Peltoboykinolic Acid from Astilbe rubra Attenuates TGF-β1-Induced Epithelial-to-Mesenchymal Transitions in Lung Alveolar Epithelial Cells

Epithelial-to-mesenchymal transition (EMT) is increasingly recognized as contributing to the pathogenesis of idiopathic pulmonary fibrosis. Therefore, novel plant-based natural, active compounds have been sought for the treatment of fibrotic EMT. The aim of the present study was to investigate the inhibitory effects of Astilbe rubra on TGF-β1-induced EMT in lung alveolar epithelial cells (A549). A. rubra was subjected to extraction using 70% ethanol (ARE), and ethanol extracts of the aerial part and that of the rhizome were further partitioned using various solvents. Protein expression and cell motility were investigated to evaluate the inhibitory effects of ARE on EMT. EMT occurred in A549 cells treated with TGF-β1, but was prevented by co-treatment with ARE. The dichloromethane fractions showed the strongest inhibitory effect on TGF-β1-induced EMT. β-Peltoboykinolic acid was isolated from the dichloromethane fractions of A. rubra by activity-oriented isolation. β-Peltoboykinolic acid not only attenuated TGF-β1-induced EMT, but also the overproduction of extracellular matrix components including type I collagen and fibronectin. The Smad pathway activated by TGF-β1 was inhibited by co-treatment with β-peltoboykinolic acid. Taken together, these results indicate that β-peltoboykinolic acid from A. rubra and dichloromethane fractions shows potential as an antifibrotic agent in A549 cells treated with TGF-β1.

Regulation of PTEN/AKT/FAK pathways by PPARγ impacts on fibrosis in diabetic nephropathy

Renal tubular epithelial-to-mesenchymal transition (EMT) and tubulointerstitial fibrosis (TIF) are important pathological features of diabetic nephropathy (DN). However, the regulatory mechanism underlying EMT and TIF are still unclear. Previous studies showed that the decrease in the expression of phosphatase and tensin homolog deleted on chromosome 10 (PTEN) was closely related to the aggravation of DN, but no published study showed how PTEN participated in the regulation of EMT and TIF. In this study, the rat proximal tubular epithelial cells (NRK52E) and C57BL mice and human kidney tissues were used as the research objects to investigate the mechanism underlying the regulatory effect of peroxisome proliferator-activated receptors γ (PPARγ) on PTEN and its influence on EMT and TIF, the regulation of PTEN's dual activity of lipid phosphatase/protein phosphatase by the serine threonine protein kinase B(AKT)/focal adhesion kinase (FAK) signaling pathway, and the role of PTEN in EMT and TIF. The results showed that PPARγ regulated the expression of PTEN at a transcriptional level and further regulated EMT and TIF. This dual activity could regulate the phosphorylation level of AKT and FAK and also affect FAK transcription. However, the 129 mutant of PTEN (PTEN-G129E) lost the lipid phosphatase activity, and its protein phosphatase activity was involved only in EMT and renal fibrosis through regulating FAK phosphorylation. This study systematically elucidated the role of PPARγ/PTEN/AKT/FAK signaling pathway in EMT and TIF during the pathogenesis of DN.

Role of Metabolic Reprogramming in Epithelial⁻Mesenchymal Transition (EMT)

Activation of epithelial–mesenchymal transition (EMT) is thought to be an essential step for cancer metastasis. Tumor cells undergo EMT in response to a diverse range of extra- and intracellular stimulants. Recently, it was reported that metabolic shifts control EMT progression and induce tumor aggressiveness. In this review, we summarize the involvement of altered glucose, lipid, and amino acid metabolic enzyme expression and the underlying molecular mechanisms in EMT induction in tumor cells. Moreover, we propose that metabolic regulation through gene-specific or pharmacological inhibition may suppress EMT and this treatment strategy may be applied to prevent tumor progression and improve anti-tumor therapeutic efficacy. This review presents evidence for the importance of metabolic changes in tumor progression and emphasizes the need for further studies to better understand tumor metabolism.

Curcumin: a potent agent to reverse epithelial-to-mesenchymal transition

BACKGROUND

Epithelial-to-mesenchymal transition (EMT) is involved in tumor progression, invasion, migration and metastasis. EMT is a process by which polarized epithelial cells acquire motile mesothelial phenotypic features. This process is initiated by disassembly of cell-cell contacts through the loss of epithelial markers and replacement of these markers by mesenchymal markers. Reconstruction of the cytoskeleton and degradation of the tumor basement membrane ensures the spread of invasive malignant tumor cells to distant locations. Accumulating evidence indicates that curcumin, as a well-known phytochemical, can inhibit EMT/metastasis through various mechanisms and pathways in human tumors.

CONCLUSIONS

In this review, we summarize the mechanisms by which curcumin may affect EMT in cells under pathological conditions to understand its potential as a novel anti-tumor agent. Curcumin can exert chemo-preventive effects by inhibition and reversal of the EMT process through both TGF-β-dependent (e.g. in hepatoma and retinal pigment epithelial cancer) and -independent (e.g. in oral cancer, colorectal cancer, pancreatic cancer, hepatocellular carcinoma, breast cancer, melanoma, prostate cancer, bladder cancer, thyroid cancer and lung cancer) pathways. Curcumin can also mitigate chemoresistance through EMT suppression and promotion of the antiproliferative effects of conventional chemotherapeutics. Therefore, curcumin has the potential to be used as a novel adjunctive agent to prevent tumor metastasis, which may at least partly be attributed to its hampering of the EMT process.

Curcumin inhibits the TGF-β1-dependent differentiation of lung fibroblasts via PPARγ-driven upregulation of cathepsins B and L

Pulmonary fibrosis is a progressive disease characterized by a widespread accumulation of myofibroblasts and extracellular matrix components. Growing evidences support that cysteine cathepsins, embracing cathepsin B (CatB) that affects TGF-β1-driven Smad pathway, along with their extracellular inhibitor cystatin C, participate in myofibrogenesis. Here we established that curcumin, a potent antifibrotic drug used in traditional Asian medicine, impaired the expression of both α-smooth muscle actin and mature TGF-β1 and inhibited the differentiation of human lung fibroblasts (CCD-19Lu cells). Curcumin induced a compelling upregulation of CatB and CatL. Conversely cystatin C was downregulated, which allowed the recovery of the peptidase activity of secreted cathepsins and the restoration of the proteolytic balance. Consistently, the amount of both insoluble and soluble type I collagen decreased, reaching levels similar to those observed for undifferentiated fibroblasts. The signaling pathways activated by curcumin were further examined. Curcumin triggered the expression of nuclear peroxisome proliferator-activated receptor γ (PPARγ). Contrariwise PPARγ inhibition, either by an antagonist (2-chloro-5-nitro-N-4-pyridinyl-benzamide) or by RNA silencing, restored TGF-β1-driven differentiation of curcumin-treated CCD-19Lu cells. PPARγ response element (PPRE)-like sequences were identified in the promoter regions of both CatB and CatL. Finally, we established that the transcriptional induction of CatB and CatL depends on the binding of PPARγ to PPRE sequences as a PPARγ/Retinoid X Receptor-α heterodimer.

Curcumin for the Prevention of Epithelial-Mesenchymal Transition in Endoxifen-Treated MCF-7 Breast Cancer Cel

Background: Curcumin was shown to reduce epithelial-mesenchymal transition (EMT) markers in previous short term studies. This study was aimed to investigate the potential of curcumin in the prevention of EMT activation in MCF-7 cells induced by endoxifen. Methods: MCF-7 breast cancer cells were treated with Endoxifen 1000 nM+betaestradiol 1 nM with or without curcumin (8.5μM or 17 μM). Cells treated with dimethyl sulfoxide (DMSO) 0.001% were used as negative control. After 8 weeks of continuous treatment, the cells were counted, analyzed for mRNA E-cadherin, vimentin, TGF-β expression, total reactive oxygen species (ROS) and observed for morphological changes using confocal microscope and transmission electron microscope. Result: MCF-7 cell viability was increased in endoxifen + β-estradiol group. Cell viability was significantly decreased in curcumin 17 μM, but not in curcumin 8.5 μM group. Analysis of EMT markers at week 8 indicates that there were increase in vimentin and TGF-β mRNA expressions, while E-cadherin mRNA expressions and TGF-β1 protein concentrations were shown to decrease. The results showed that administration of curcumin in all the dose administered were incapable improving the expressions of vimentin, TGF-β1 and E-cadherin. There was a decrease in ROS concentration in curcumin treated cells (8.5 μM) while in curcumin 17 μM, ROS concentration was increased. Morphological observation using confocal microscope and TEM showed the presence of mesenchymal cells and adherens junction. Conclusion: endoxifen treatments for eight weeks resulted in upregulation of EMT markers and changes in morphology of MCF-7 breast cancer cells. The addition of curcumin did not prevent the activation of EMT.

Gambogic acid suppresses cancer invasion and migration by inhibiting TGFβ1-induced epithelial-to-mesenchymal transition

The epithelial-to-mesenchymal transition (EMT) contributes to the disruption of cell–cell junctions and imbues cancer cells with invasive and migratory properties. In this study, we investigated the effect of gambogic acid, a xanthone extracted from the resin of Garciania hanburyi, on transforming growth factor β1 (TGFβ1)-induced EMT. Gambogic acid inhibited the invasion and migration of TGFβ1-induced A549 cells in vitro. Gambogic acid also increased the mRNA and protein expression of E-cadherin, but repressed the mRNA and protein expression of N-cadherin, vimentin, and transcription factor TWIST1. Further examination of the mechanism revealed that the nuclear factor κB (NF-κB) pathway is involved in this regulation of EMT-related biomarkers. Gambogic acid inhibited NF-κB p65 nuclear translocation and the phosphorylation of the inhibitor of NF-κB (IκBα) and IκBα kinase (IKKα). Gambogic acid also suppressed the EMT induced by TGFβ1 and tumor necrosis factor α by inhibiting the NF-κB pathway. Our data also indicate that gambogic acid inhibited the primary lesion and lung metastasis of orthotopic model of A549 cells in vivo. We propose that gambogic acid might be developed as a candidate drug with therapeutic potential for the treatment of cancer invasion and migration.

Clock represses preadipocytes adipogenesis via GILZ

Adiposity is a worldwide health threat that needs to be prevented. Circadian gene Clock (circadian locomotor output cycles kaput) is closely correlated to adiposity; for example, weight gain, adipocytes size expansion, and serum lipid level rise in Clock^Δ19 mice compared to C57BL/6J mice. However, the precise role of Clock during adipogenic differentiation is unknown. Herein, the circadian gene Clock is shown to regulate adipogenesis mediated by GILZ. Clock-mediated attenuation and upregulation influenced lipid synthesis and affected the levels of adipogenic transcriptional factors, C/EBP-β, C/EBP-α, PPAR-γ, and FABP4, both in vivo and in vitro (primary adipose-derived stromal cells and 3T3-L1 cells). Chromatin immunoprecipitation (ChIP) assay, reporter gene assay, and serum shock assay found that Clock transcriptionally regulated the glucocorticoid-induced leucine zipper (GILZ). Furthermore, GILZ attenuation could relieve the inhibitory effect of Clock on lipid synthesis and GILZ overexpression also reduced the promotion role of Clock attenuation in adipogenesis suggesting that Clock inhibits adipogenic differentiation of preadipocytes via GILZ. The current results demonstrate how circadian genes are likely to regulate adiposity, affecting the adipogenic differentiation process, as well as, increasing the fat cells number. Therefore, this study may provide novel insights into the underlying mechanism explaining the correlation between Clock mutation and adiposity.

Renal tubular epithelium-targeted peroxisome proliferator-activated receptor-γ maintains the epithelial phenotype and antagonizes renal fibrogenesis

Accumulating evidence suggests that loss of the renal tubular epithelial phenotype plays an important role in the pathogenesis of renal tubulointerstitial fibrosis. Systemic activation of peroxisome proliferator-activated receptor γ (PPAR-γ) has been shown to be protective against renal fibrosis, although the mechanisms are poorly understood. The present study aimed to define the role of renal tubular epithelium-targeted PPAR-γ in protection of the epithelial phenotype and the antagonism of renal fibrosis and to define the underlying mechanisms. In response to TGF-β1 challenge, PPAR-γ expression and activity in the renal proximal tubule epithelial cells (RPTECs) were significantly reduced, and the reduction was accompanied by decreased E-cadherin and elevated α-SMA, indicating a loss of the epithelial phenotype. Oxidative stress induced by TGF-β1 was shown to be attributed to the alteration of the epithelial phenotype and PPAR-γ inhibition. Activation of PPAR-γ by its agonists of rosiglitazone and 15d-PGJ2 or genetic overexpression of PPAR-γ prevented the loss of the epithelial phenotype induced by TGF-β1 in line with the inhibition of oxidative stress. To explore the role of PPAR-γ in renal tubular epithelial in antagonizing fibrogenesis, PPAR-γ was specifically deleted from RPTECs in mice. Following unilateral ureteral obstruction, the fibrosis was markedly deteriorated in mice with PPAR-γ invalidation in RPTECs. Treatment with rosiglitazone attenuated tubulointerstitial fibrosis and epithelial phenotype transition in WT but not proximal tubule PPAR-γ KO mice. Taken together, these findings identified an important role of renal tubular epithelium-targeted PPAR-γ in maintaining the normal epithelial phenotype and opposing fibrogenesis, possibly via antagonizing oxidative stress.

Highly Dispersible and Bioavailable Curcumin but not Native Curcumin Induces Brown-Like Adipocyte Formation in Mice

SCOPE

The induction of brown-like adipocytes in white adipose tissue (WAT) is a potential therapeutic target for the treatment of obesity and metabolic disorders via the ability of these cells to release excess energy as heat in association with uncoupling protein 1. Some experimental trials suggest that curcumin (a yellow pigment from turmeric) has a suppressive effect on the accumulation of body fat. However, there is little evidence to show that curcumin induces the formation of brown-like adipocytes and the molecular mechanisms involved remain elusive. In addition, in most experimental trials, high doses of curcumin are administered.

METHODS AND RESULTS

Highly dispersible and bioavailable curcumin (HC, i.e., 4.5 mg native curcumin kg^-1 ) but not the same dose of native curcumin induces the formation of brown-like adipocytes in mouse inguinal WAT. Moreover, the formation of brown-like adipocytes induced by HC in inguinal WAT may be mediated by the production of local norepinephrine from accumulated alternatively activated macrophages.

CONCLUSION

These novel findings suggest that curcumin increases energy expenditure by inducing the formation of brown-like adipocytes via a unique molecular mechanism. Importantly, they show that HC has significant bioactive effects in vivo at lower doses of curcumin.

CDK5 promotes renal tubulointerstitial fibrosis in diabetic nephropathy via ERK1/2/PPARγ pathway

Cyclin-dependent kinase 5 (CDK5) has been documented in podocyte injuries in diabetic nephropathy (DN), however its role in renal tubular epithelial cells has not been elucidated. We report here that CDK5 is detrimental and promotes tubulointerstitial fibrosis (TIF) via the extracellular signal-regulated kinase 1/2 (ERK1/2)/peroxisome proliferator-activated receptor gamma (PPRAγ) pathway in DN. In high glucose cultured NRK52E cells, blocking CDK5 activity inhibited epithelial-to-mesenchymal transition (EMT) and fibrosis via ERK1/2/PPARγ pathway. In diabetic rats, CDK5 inhibitor roscovitine decreased renal fibrosis and improved renal function as demonstrated by a decrease in levels of blood urine nitrogen (BUN), serum creatinine and β2-microglobulin. Further studies revealed that improved renal fibrosis and function in diabetic rats were associated with inactivation of ERK1/2 and PPARγ signaling pathways. In late staged DN patients, the upregulation of CDK5 and p35 activated phosphorylated ERK1/2 and PPARγ, leading to decreased levels of E-cadherin but increased Vimentin and Collagen IV. Accordingly, renal fibrosis and function were worsened as revealed by decreased estimated glomerular filtration rate (eGFR) and increased serum BUN, creatinine, β2-microglobulin, 24-hour proteinuria and urine albumin to creatinine ratio (UACR). These findings demonstrate a novel mechanism that CDK5 increases tubulointerstitial fibrosis by activating the ERK1/2/PPARγ pathway and EMT in DN. CDK5 might have therapeutic potential in diabetic nephropathy.

Molecular docking analysis of curcumin analogues against kinase domain of ALK5

During metastasis, cancer cells transcend from primary site to normal cells area upon attaining epithelial to mesenchymal transition (EMT) causing malignant cancer disease. Increased expression of TGF-β and its receptor ALK5 is an important hallmark of malignant cancer. In the present study, efficacy of curcumin and its analogues as inhibitors of ALK5 (TGFβR-I) receptor was evaluated using in silico approaches. A total of 142 curcumin analogues and curcumin were retrieved from peer reviewed literature and constructed a combinatorial library. Further their drug-likeness was assessed using Molinspiration, cheminformatics and preADMET online servers. The interaction of 142 curcumin analogues and curcumin with ALK5 receptor was studied using Autodock Vina. This study revealed six curcumin analogues as promising ALK5 inhibitors with significant binding energy and H-bonding interaction.

Eucalyptol ameliorates Snail1/β-catenin-dependent diabetic disjunction of renal tubular epithelial cells and tubulointerstitial fibrosis

Renal tubulointerstitial fibrosis is an important event in the pathogenesis of diabetic nephropathy. Under pathologic conditions, renal tubular epithelial cells undergo transition characterized by loss of cell-cell adhesion and increased cell migration. This study investigated that eucalyptol inhibited tubular epithelial cell disjunction and tubulointerstitial fibrosis stimulated by glucose. Human renal proximal tubular epithelial cells were incubated for up to 72 h in media containing 27.5 mM mannitol as osmotic controls or 33 mM glucose in the presence of 1-20 μM eucalyptol. Nontoxic eucalyptol inhibited glucose-induced expression of the mesenchymal markers of N-cadherin and α-smooth muscle actin, whereas the induction of E-cadherin was enhanced. Eucalyptol attenuated the induction of connective tissue growth factor and collagen IV by glucose, whereas the membrane type 1-matrix metalloproteinase expression was enhanced with reducing tissue inhibitor of metalloproteinase-2 expression. Oral administration of 10 mg/kg eucalyptol to db/db mice for 8 weeks blunted hyperglycemia and proteinuria. Eucalyptol reversed tissue levels of E-cadherin, N-cadherin and P-cadherin and the collagen fiber deposition in diabetic kidneys. Eucalyptol attenuated the induction of Snail1, β-catenin and integrin-linked kinase 1 (ILK1) in glucose-exposed tubular cells and diabetic kidneys, and the glycogen synthase kinase (GSK)-3β expression was reversely enhanced. Glucose prompted TGF-β1 production in tubular cells, leading to induction of Snail1, β-catenin and ILK1, which was dampened by eucalyptol. Furthermore, the Snail1 gene deletion encumbered the β-catenin induction in glucose/eucalyptol-treated tubular cells accompanying enhanced GSK-3β expression. Therefore, eucalyptol may antagonize hyperglycemia-induced tubular epithelial derangement and tubulointerstitial fibrosis through blocking ILK1-dependent transcriptional interaction of Snail1/β-catenin.

Shenqiwan Ameliorates Renal Fibrosis in Rats by Inhibiting TGF-β1/Smads Signaling Pathway

Epithelial-mesenchymal transition (EMT) refers to the transition of epithelial cells into mesenchymal cells. Emerging evidence suggests that EMT is a key point in renal interstitial fibrosis (RIF). Traditional Chinese Medicine Shenqiwan (SQW) is widely used in clinical treatment of chronic kidney disease, but the underlying mechanism remains unclear. The purpose of this study is to investigate the effect of SQW on renal fibrosis and its association with TGF-β1/Smads signaling pathway. A rat model of adenine (150 mg/kg) was established and intragastrically treated with various concentrations of SQW at dose of 1.5 g/kg, 3 g/kg, and 6 g/kg. Control group and model group were given the same volume of saline. Meanwhile, the positive control group was treated with Enalapril (4 mg/kg). Animals were sacrificed on 21st day after administration. The results showed that SQW could significantly relieve renal pathological damage caused by adenine, increase gene and protein expression of E-cadherin, and decrease the expression of Vimentin in kidney samples. In addition, SQW efficiently inhibited the mRNA and protein expression of p-Smad2/3 by upregulating Smad7. These results suggest that SQW could slow down the progression of renal fibrosis, possibly by inhibiting TGF-β1/Smads signaling pathway.

Recent Advances of Curcumin in the Prevention and Treatment of Renal Fibrosis

Curcumin, a polyphenol derived from the turmeric, has received attention as a potential treatment for renal fibrosis primarily because it is a relatively safe and inexpensive compound that contributes to kidney health. Here, we review the literatures on the applications of curcumin in resolving renal fibrosis in animal models and summarize the mechanisms of curcumin and its analogs (C66 and (1E,4E)-1,5-bis(2-bromophenyl) penta-1,4-dien-3-one(B06)) in preventing inflammatory molecules release and reducing the deposition of extracellular matrix at the priming and activation stage of renal fibrosis in animal models by consulting PubMed and Cnki databases over the past 15 years. Curcumin exerts antifibrotic effect through reducing inflammation related factors (MCP-1, NF-κB, TNF-α, IL-1β, COX-2, and cav-1) and inducing the expression of anti-inflammation factors (HO-1, M6PRBP1, and NEDD4) as well as targeting TGF-β/Smads, MAPK/ERK, and PPAR-γ pathways in animal models. As a food derived compound, curcumin is becoming a promising drug candidate for improving renal health.

Genomic reprograming analysis of the Mesothelial to Mesenchymal Transition identifies biomarkers in peritoneal dialysis patients

Peritoneal dialysis (PD) is an effective renal replacement therapy, but a significant proportion of patients suffer PD-related complications, which limit the treatment duration. Mesothelial-to-mesenchymal transition (MMT) contributes to the PD-related peritoneal dysfunction. We analyzed the genetic reprograming of MMT to identify new biomarkers that may be tested in PD-patients. Microarray analysis revealed a partial overlapping between MMT induced in vitro and ex vivo in effluent-derived mesothelial cells, and that MMT is mainly a repression process being higher the number of genes that are down-regulated than those that are induced. Cellular morphology and number of altered genes showed that MMT ex vivo could be subdivided into two stages: early/epithelioid and advanced/non-epithelioid. RT-PCR array analysis demonstrated that a number of genes differentially expressed in effluent-derived non-epithelioid cells also showed significant differential expression when comparing standard versus low-GDP PD fluids. Thrombospondin-1 (TSP1), collagen-13 (COL13), vascular endothelial growth factor A (VEGFA), and gremlin-1 (GREM1) were measured in PD effluents, and except GREM1, showed significant differences between early and advanced stages of MMT, and their expression was associated with a high peritoneal transport status. The results establish a proof of concept about the feasibility of measuring MMT-associated secreted protein levels as potential biomarkers in PD.

Curcumin Suppresses Intestinal Fibrosis by Inhibition of PPARγ-Mediated Epithelial-Mesenchymal Transition

Intestinal fibrotic stricture is a major complication of Crohn's disease (CD) and epithelial-to-mesenchymal transition (EMT) is considered as an important contributor to the formation of intestinal fibrosis by increasing extracellular matrix (ECM) proteins. Curcumin, a compound derived from rhizomes of Curcuma, has been demonstrated with a potent antifibrotic effect. However, its effect on intestinal fibrosis and the potential mechanism is not completely understood. Here we found that curcumin pretreatment significantly represses TGF-β1-induced Smad pathway and decreases its downstream α-smooth muscle actin (α-SMA) gene expression in intestinal epithelial cells (IEC-6); in contrast, curcumin increases expression of E-cadherin and peroxisome proliferator-activated receptor γ (PPARγ) in IEC-6. Moreover, curcumin promotes nuclear translocation of PPARγ and the inhibitory effect of curcumin on EMT could be reversed by PPARγ antagonist GW9662. Consistently, in the rat model of intestinal fibrosis induced by 2,4,5-trinitrobenzene sulphonic acid (TNBS), oral curcumin attenuates intestinal fibrosis by increasing the expression of PPARγ and E-cadherin and decreasing the expression of α-SMA, FN, and CTGF in colon tissue. Collectively, these results indicated that curcumin is able to prevent EMT progress in intestinal fibrosis by PPARγ-mediated repression of TGF-β1/Smad pathway.

Clinical Trials in Pediatric Autosomal Dominant Polycystic Kidney Disease

Autosomal dominant polycystic kidney disease (ADPKD) is the most common hereditary kidney disease and is associated with concerning long-term implications for kidney function and cardiovascular health. Early intervention is needed in order to mitigate these long-term complications. Herein, we review important findings from recent clinical trials in ADPKD and their relevance to affected children and young adults and consider future directions for intervention. Recent clinical trials support aggressive control of blood pressure with blockade of the renin-angiotensin-aldosterone system as well as potential benefit of pravastatin therapy in children and young adults with ADPKD. There are several other candidate therapies, some of which have shown benefit in adult ADPKD, which require further investigation in affected children.

The anti-hepatic fibrosis activity of ergosterol depended on upregulation of PPARgamma in HSC-T6 cells

Advanced glycation endproducts (AGEs) were shown to play an important role in metabolic syndrome and were suggested to contribute to the development of hepatic fibrosis. Evidence indicates that AGEs resulted in hepatic fibrosis coupled to the activation of the receptor for AGEs (RAGE) in hepatic stellate cells (HSCs). NADPH oxidase is downstream of the RAGE signaling pathway, resulting in an increase in reactive oxygen species (ROS), alpha-smooth muscle actin (alpha-SMA), RAGE, and matrix metalloproteinase-9 (MMP-9). This study was designed to evaluate the effects of ergosterol on RAGE signaling in HSC-T6 cells. Ergosterol suppressed the activation of HSC-T6 cells induced by AGEs, and attenuated overexpressions of alpha-SMA, MMP-9, and epithelial-mesenchymal transition (EMT) markers, including N-cadherin and vimentin. We also found that these inhibitory effects of ergosterol on the activation of HSCs were dependent on peroxisome proliferator-activated receptor-gamma (PPARgamma) confirmed by PPARgamma reporter assay and PPARgamma knockdown. In addition, ergosterol also showed an inhibitory effect on the generation of AGEs, fructosamine, and α-dicarbonyl compounds in this study. Our results show that ergosterol can be used as a protective agent against hepatic fibrosis caused by induction of AGEs.

Curcumin as potential therapeutic natural product: a nanobiotechnological perspective

OBJECTIVES

Nanotechnology-based drug delivery systems can resolve the poor bioavailability issue allied with curcumin. The therapeutic potential of curcumin can be enhanced by making nanocomposite preparation of curcumin with metal oxide nanoparticles, poly lactic-co-glycolic acid (PLGA) nanoparticles and solid lipid nanoparticles that increases its bioavailability in the tissue.

KEY FINDINGS

Curcumin has manifold therapeutic effects which include antidiabetic, antihypertensive, anticancer, anti-inflammatory and antimicrobial properties. Curcumin can inhibit diabetes, heavy metal and stress-induced hypertension with its antioxidant, chelating and inhibitory effects on the pathways that lead to hypertension. Curcumin is an anticancer agent that can prevent abnormal cell proliferation. Nanocurcumin is an improved form of curcumin with enhanced therapeutic properties due to improved delivery to the diseased tissue, better internalization and reduced systemic elimination.

SUMMARY

Curcumin has multiple pharmacologic effects, but its poor bioavailability reduces its therapeutic effects. By conjugating curcumin to metal oxide nanoparticles or encapsulation in lipid nanoparticles, dendrimers, nanogels and polymeric nanoparticles, the water solubility and bioavailability of curcumin can be improved and thus increase its pharmacological effectiveness.

A High Content Screening Assay to Identify Compounds with Anti-Epithelial-Mesenchymal Transition Effects from the Chinese Herbal Medicine Tong-Mai-Yang-Xin-Wan

Chronic kidney disease (CKD) is a worldwide health problem with growing prevalence in developing countries. Renal tubular epithelial-mesenchymal transition (EMT) is a critical step and key factor in the development of this condition. Renal tubulointerstitial fibrosis is a basic pathological change at the later stages of the disease. Therefore, blocking the development of EMT could be a critical factor in curing CKD. We have established a cell-based high-content screening (HCS) method to identify inhibitors of EMT in human proximal tubular epithelial (HK-2) cells by automatic acquisition and processing of dual-fluorescent labeled images. With the aid of chromatographic separation and mass spectrometry, we achieved the rapid and reliable screening of active compounds from the Chinese herbal medicine Tong-Mai-Yang-Xin-Wan (TMYX) for treating EMT. Five fractions were found to exert anti-EMT activity and were further identified by liquid chromatography coupled with tandem mass spectrometry. Glycyrrhizic acid, glyasperin A, and licorisoflavan A were found to inhibit EMT. The proposed approach was successfully applied to screen active compounds from TMYX on TGF-β1-stimulated HK-2 cells and may offer a new means for identifying lead compounds for treating EMT from registered Chinese herbal medicines.

Chemical regulators of epithelial plasticity reveal a nuclear receptor pathway controlling myofibroblast differentiation

Plasticity in epithelial tissues relates to processes of embryonic development, tissue fibrosis and cancer progression. Pharmacological modulation of epithelial transitions during disease progression may thus be clinically useful. Using human keratinocytes and a robotic high-content imaging platform, we screened for chemical compounds that reverse transforming growth factor β (TGF-β)-induced epithelial-mesenchymal transition. In addition to TGF-β receptor kinase inhibitors, we identified small molecule epithelial plasticity modulators including a naturally occurring hydroxysterol agonist of the liver X receptors (LXRs), members of the nuclear receptor transcription factor family. Endogenous and synthetic LXR agonists tested in diverse cell models blocked α-smooth muscle actin expression, myofibroblast differentiation and function. Agonist-dependent LXR activity or LXR overexpression in the absence of ligand counteracted TGF-β-mediated myofibroblast terminal differentiation and collagen contraction. The protective effect of LXR agonists against TGF-β-induced pro-fibrotic activity raises the possibility that anti-lipidogenic therapy may be relevant in fibrotic disorders and advanced cancer.

Hydroxysafflor Yellow A Ameliorates Renal Fibrosis by Suppressing TGF-β1-Induced Epithelial-to-Mesenchymal Transition

OBJECTIVE

Renal fibrosis is the common pathological foundation of many chronic kidney diseases (CKDs). The aim of this study was to investigate whether Hydroxysafflor yellow A (HSYA) can preserve renal function by inhibiting the progression of renal fibrosis and the potential mechanisms.

METHODS

Renal fibrosis was induced by unilateral ureteral obstruction (UUO) performed on 7-week-old C57BL/6 mice. HSYA (10, 50 and 100 mg/kg) were intragastrically administered. Sham group and model group were administered with the same volume of vehicle. Serum and kidney samples were collected 14 days after the UUO surgery. Serum biochemical indicators were measured by automatic biochemical analyzer. Histological changes were evaluated by HE and Masson staining. In vitro, the anti-fibrotic effect of HSYA was tested on human recombinant transforming growth factor-β1 (TGF-β1) stimulated HK-2 cells. The protein levels of α-SMA, collagen-I and fibronectin in kidney tissue and HK-2 cells were measured by immunohistochemistry and immunofluorescence. The protein levels of apoptosis-relative and TGF-β1/Smad3 signaling were detected by western blot.

RESULTS

HSYA slowed the development of renal fibrosis both in vivo and in vitro. In UUO rats, renal function index suggested that HSYA treatment decreased the level of serum creatinine (Scr) and blood urea nitrogen (BUN) rose by UUO (P<0.05). HE staining and Masson staining demonstrated that kidney interstitial fibrosis, tubular atrophy, and inflammatory cell infiltration were notably attenuated in the high-dose HSYA group compared with the model group. The expressions of α-SMA, collagen-I and fibronectin were decreased in the UUO kidney and HK-2 cells of the HSYA-treatment group. Moreover, HSYA reduced the apoptotic rate of HK-2 cells stimulated by TGF-β1. Further study revealed that HSYA regulated the TGF-β1/Smads signaling pathway both in kidney tissue and HK-2 cells.

CONCLUSIONS

These results suggested that HSYA had a protective effect against fibrosis in renal cells, at least partly, through inhibiting TGF-β1/smad3-mediated Epithelial-mesenchymal transition signaling pathway.

Role of Wnt Inhibitory Factor-1 in Inhibition of Bisdemethoxycurcumin Mediated Epithelial-to-Mesenchymal Transition in Highly Metastatic Lung Cancer 95D Cells

Background:

Bisdemethoxycurcumin (BDMC) is an active component of curcumin and a chemotherapeutic agent, which has been suggested to inhibit tumor growth, invasion and metastasis in multiple cancers. But its contribution and mechanism of action in invasion and metastasis of non-small cell lung cancer (NSCLC) are not very clear. Therefore, we tried to study the effects of BDMC on regulation of epithelial-to-mesenchymal transition (EMT), which is closely linked to tumor cell invasion and metastasis.

Methods:

In this study, we first induced transforming growth factor-β1 (TGF-β1) mediated EMT in highly metastatic lung cancer 95D cells. Thereafter, we studied the effects of BDMC on invasion and migration of 95D cells. In addition, EMT markers expressions were also analyzed by western blot and immunofluorescence assays. The contribution of Wnt inhibitory factor-1 (WIF-1) in regulating BDMC effects on TGF-β1 induced EMT were further analyzed by its overexpression and small interfering RNA knockdown studies.

Results:

It was observed that BDMC inhibited the TGF-β1 induced EMT in 95D cells. Furthermore, it also inhibited the Wnt signaling pathway by upregulating WIF-1 protein expression. In addition, WIF-1 manipulation studies further revealed that WIF-1 is a central molecule mediating BDMC response towards TGF-β1 induced EMT by regulating cell invasion and migration.

Conclusions:

Our study concluded that BDMC effects on TGF-β1 induced EMT in NSCLC are mediated through WIF-1 and elucidated a novel mechanism of EMT regulation by BDMC.

Hydrogen Sulfide Inhibits Transforming Growth Factor-β1-Induced EMT via Wnt/Catenin Pathway

Hydrogen sulfide (H2S) has anti-fibrotic potential in lung, kidney and other organs. The exogenous H2S is released from sodium hydrosulfide (NaHS) and can influence the renal fibrosis by blocking the differentiation of quiescent renal fibroblasts to myofibroblasts. But whether H2S affects renal epithelial-to-mesenchymal transition (EMT) and the underlying mechanisms remain unknown. Our study is aimed at investigating the in vitro effects of H2S on transforming growth factor-β1 (TGF-β1)-induced EMT in renal tubular epithelial cells (HK-2 cells) and the associated mechanisms. The induced EMT is assessed by Western blotting analysis on the expressions of α-SMA, E-cadherin and fibronectin. HK-2 cells were treated with NaHS before incubating with TGF-β1 to investigate its effect on EMT and the related molecular mechanism. Results demonstrated that NaHS decreased the expression of α-SMA and fibronectin, and increased the expression of E-cadherin. NaHS reduced the expression of TGF-β receptor type I (TβR I) and TGF-β receptor type II (TβR II). In addition, NaHS attenuated TGF-β1-induced increase of β-catenin expression and ERK phosphorylation. Moreover, it inhibited the TGF-β1-induced nuclear translocation of ββ-catenin. These effects of NaHS on fibronectin, E-cadherin and TβR I were abolished by the ERK inhibitor U0126 or β-catenin inhibitor XAV939, or β-catenin siRNA interference. We get the conclusion that NaHS attenuated TGF-β1-induced EMT in HK-2 cells through both ERK-dependent and β-catenin-dependent pathways.

Curcumin Suppresses Phthalate-Induced Metastasis and the Proportion of Cancer Stem Cell (CSC)-like Cells via the Inhibition of AhR/ERK/SK1 Signaling in Hepatocellular Carcinoma

Recent evidence indicating that phthalates promote cancer development, including cell proliferation, migration, and invasion, has raised public health concerns. Here, we show that bis(2-ethylhexyl) phthalate promotes the migration, invasion, and epithelial-mesenchymal transition of hepatocellular carcinoma cells. In addition, bis(2-ethylhexyl) phthalate increased the proportion of cancer stem cell (CSC)-like cells and stemness maintenance in vitro as well as tumor growth and metastasis in vivo. The various activities of curcumin, including anticancer, anti-inflammation, antioxidation, and immunomodulation, have been investigated extensively. Curcumin suppressed phthalate-induced cell migration, invasion, and epithelial-mesenchymal transition, decreased the proportion of CSC-like cells in hepatocellular carcinoma cell lines in vitro, and inhibited tumor growth and metastasis in vivo. We also reveal that curcumin suppressed phthalate-induced migration, invasion, and CSC-like cell maintenance through inhibition of the aryl hydrocarbon receptor/ERK/SK1/S1P3 signaling pathway. Our results suggest that curcumin may be a potential antidote for phthalate-induced cancer progression.

Effects and mechanism of miR-23b on glucose-mediated epithelial-to-mesenchymal transition in diabetic nephropathy

MicroRNAs (miRNAs) play important roles in epithelial-to-mesenchymal transition (EMT). Moreover, hyperglycaemia induces damage to renal tubular epithelial cells, which may lead to EMT in diabetic nephropathy. However, the effects of miRNAs on EMT in diabetic nephropathy are poorly understood. In the present study, we found that the level of microRNA-23b (miR-23b) was significantly decreased in high glucose (HG)-induced human kidney proximal tubular epithelial cells (HK2) and in kidney tissues of db/db mice. Overexpression of miR-23b attenuated HG-induced EMT, whereas knockdown of miR-23b induced normal glucose (NG)-mediated EMT in HK2 cells. Mechanistically, miR-23b suppressed EMT in diabetic nephropathy by targeting high mobility group A2 (HMGA2), thereby repressing PI3K-AKT signalling pathway activation. Additionally, HMGA2 knockdown or inhibition of the PI3K-AKT signalling pathway with LY294002 mimicked the effects of miR-23b overexpression on HG-mediated EMT, whereas HMGA2 overexpression or activation of the PI3K-AKT signalling pathway with BpV prevented the effects of miR-23b on HG-mediated EMT. We also confirmed that overexpression of miR-23b alleviated EMT, decreased the expression levels of EMT-related genes, ameliorated renal morphology, glycogen accumulation, fibrotic responses and improved renal functions in db/db mice. Taken together, we showed for the first time that miR-23b acts as a suppressor of EMT in diabetic nephropathy through repressing PI3K-AKT signalling pathway activation by targeting HMGA2, which maybe a potential therapeutic target for diabetes-induced renal dysfunction.

TGF-β/BMP proteins as therapeutic targets in renal fibrosis. Where have we arrived after 25 years of trials and tribulations?

The understanding of renal fibrosis in chronic kidney disease (CKD) remains as a challenge. More than 10% of the population of developed countries suffer from CKD. Proliferation and activation of myofibroblasts and accumulation of extracellular matrix proteins are the main features of kidney fibrosis, a process in which a large number of cytokines are involved. Targeting cytokines responsible for kidney fibrosis development might be an important strategy to face the problem of CKD. The increasing knowledge of the signaling pathway network of the transforming growth factor beta (TGF-β) superfamily members, such as the profibrotic cytokine TGF-β1 or the bone morphogenetic proteins (BMPs), and their involvement in the regulation of kidney fibrosis, has stimulated numerous research teams to look for potential strategies to inhibit profibrotic cytokines or to enhance the anti-fibrotic actions of other cytokines. The consequence of all these studies is a better understanding of all these canonical (Smad-mediated) and non-canonical signaling pathways. In addition, the different receptors involved for signaling of each cytokine, the different combinations of type I-type II receptors, and the presence and function of co-receptors that can influence the biological response have been also described. However, are these studies leading to suitable strategies to block the appearance and progression of kidney fibrosis? In this review, we offer a critical perspective analyzing the achievements using the most important strategies developed up till now: TGF-β antibodies, chemical inhibitors of TGF-β receptors, miRNAs and signaling pathways and BMP agonists with a potential role as therapeutic molecules against kidney fibrosis.

Curcumin inhibits hypoxia-induced migration in K1 papillary thyroid cancer cells

Curcumin, traditionally used as food and medicinal purposes, has recently been reported to have protective efficacy against hypoxia. Hypoxia is one of the important reactive factors in tumor metastasis, which is a key problem in clinical thyroid cancer therapy. In present study, we investigate the anti-metastatic effect of curcumin on the K1 papillary thyroid cancer cells as well as its potential mechanisms. The results show that curcumin effectively inhibits hypoxia-induced reactive oxygen species (ROS) upregulation and significantly decreases the mRNA and protein expression levels of hypoxia-inducible factor-1α (HIF-1α) in K1 cells. Curcumin also decreases the DNA binding ability of HIF-1α to hypoxia response element (HRE). Furthermore, curcumin enhances E-cadherin expression, inhibits metalloproteinase-9 (MMP-9) enzyme activity, and weakens K1 cells migration under hypoxic conditions. In summary, these results indicate that curcumin possesses a potent anti-metastatic effect and might be an effective tumoristatic agent for the treatment of aggressive papillary thyroid cancers.

Chrysin inhibits diabetic renal tubulointerstitial fibrosis through blocking epithelial to mesenchymal transition

Renal fibrosis is a crucial event in the pathogenesis of diabetic nephropathy (DN). The process known as epithelial to mesenchymal transition (EMT) contributes to the accumulation of matrix proteins in kidneys, in which renal tubular epithelial cells play an important role in progressive renal fibrosis. The current study investigated that chrysin (5,7-dihydroxyflavone) present in bee propolis and herbs, inhibited renal tubular EMT and tubulointerstitial fibrosis due to chronic hyperglycemia. Human renal proximal tubular epithelial cells (RPTEC) were incubated in media containing 5.5 mM glucose, 27.5 mM mannitol (as an osmotic control), or 33 mM glucose (HG) in the absence and presence of 1-20 μM chrysin for 72 h. Chrysin significantly inhibited high glucose-induced renal EMT through blocking expression of the mesenchymal markers vimentin, α-smooth muscle actin, and fibroblast-specific protein-1 in RPTEC and db/db mice. Chrysin reversed the HG-induced down-regulation of the epithelial marker E-cadherin and the HG-enhanced N-cadherin induction in RPTEC. In addition, chrysin inhibited the production of collagen IV in tubular cells and the deposition of collagen fibers in mouse kidneys. Furthermore, chrysin blocked tubular cell migration concurrent with decreasing matrix metalloproteinase-2 activity, indicating epithelial cell derangement and tubular basement membrane disruption. Chrysin restored the induction of the tight junction proteins Zona occludens protein-1 (ZO-1) and occludin downregulated in diabetic mice. Chrysin inhibited renal tubular EMT-mediated tubulointerstitial fibrosis caused by chronic hyperglycemia. Therefore, chrysin may be a potent renoprotective agent for the treatment of renal fibrosis-associated DN.

KEY MESSAGES

• Glucose increases renal tubular epithelial induction of vimentin, α-SMA and FSP-1. • Glucose enhances renal EMT by blocking tubular epithelial E-cadherin expression. • Chrysin inhibits tubular EMT-mediated tubulointerstitial fibrosis in mouse kidneys. • Chrysin restores renal tubular induction of ZO-1 and occludin downregulated in diabetic mice. • Chrysin blocks glucose-induced renal tubular cell migration with reducing MMP-2 activity.

Curcumin protects renal tubular epithelial cells from high glucose-induced epithelial-to-mesenchymal transition through Nrf2-mediated upregulation of heme oxygenase-1

Curcumin has been observed to exhibit an anti-fibrotic effect in the liver, lung and gallbladder. However, the mechanisms underlying the cytoprotective effects of curcumin remain to be elucidated. The epithelial-to-mesenchymal transition (EMT) of mature tubular epithelial cells in the kidney is considered to contribute to the renal accumulation of matrix proteins associated with diabetic nephropathy. The EMT is also closely associated with the progression of renal interstitial fibrosis and oxidative stress. This process may occur through abrogation of high glucose (HG)-induced oxidative stress via activation of nuclear factor (erythroid-derived 2)-like 2 (Nrf2) and heme oxygenase-1 (HO-1) in kidney tubular epithelial cells. In the present study, the effect of curcumin on HG-induced EMT in the NRK-52E normal rat kidney tubular epithelial cell line was investigated, and whether the effect of curcumin was mediated by the induction of Nrf2 and HO-1 expression was examined. The present study revealed that curcumin was able to prevent events associated with EMT, including the downregulation of E-cadherin and the increased expression of α-smooth muscle actin. Further analysis revealed that the expression levels of Nrf2 and HO-1 protein were elevated to a greater extent in the curcumin pretreated NRK-52E cells compared with those of the control. Notably, knockdown of Nrf2 with small interfering RNA prevented the curcumin-induced elevation in expression of HO-1 and the associated anti-fibrotic effects. In conclusion, the present findings suggested that curcumin may be significant in cellular antioxidant defense, through the activation of Nrf2 and HO-1, thereby protecting the NRK-52E cells from HG-induced EMT.

Schizandrin inhibits fibrosis and epithelial-mesenchymal transition in transforming growth factor-β1-stimulated AML12 cells

The transforming growth factor (TGF)-β1 plays a crucial role in the induction of the epithelial-to-mesenchymal transition (EMT) in hepatocytes, which contributes to the pathogenesis of liver fibrosis. The inhibition of the TGF-β1 cascade suppresses EMT and the resultant fibrosis. Schizandrin (Sch) has various therapeutic effects on a range of medical conditions such as anti-asthmatic, anti-cancer, and anti-inflammatory effects. However, the effect of Sch on TGF-β1-stimulated hepatic fibrosis and EMT is still unknown. In the present investigation, we evaluated the anti-fibrotic and anti-EMT properties of Sch and its underlying mechanisms in murine hepatocyte AML12 cells. Overall, we found that Sch inhibited the pro-fibrotic activity of TGF-β1 in AML12 cells; thus, it suppressed the accumulation of ECM proteins. Also, Sch inhibited the EMT as assessed by reduced expression of vimentin and fibronectin, and increased E-cadherin and ZO-1 in TGF-β1 induced AML12 cells. Sch reduced TGF-β1-mediated phosphorylation of Smad2/3 and Smad3/4 DNA binding activity. On the other hand, Sch reduced TGF-β1-induced ERK1/2 and PI3K/Akt phosphorylation in the non-Smad pathway. In conclusion, Sch can antagonize TGF-β1-mediated fibrosis and EMT in AML12 cells. Sch may possess potential as an anti-fibrotic molecule in the treatment of liver fibrosis.

Surface modification of titanium with curcumin: a promising strategy to combat fibrous encapsulation

Fibrous encapsulation that prevents the direct contact between an implant and the bone can cause implant failure. However, prevention of fibrous encapsulation is difficult because of the lack of effective strategies which can selectively control the growth of fibroblasts and osteoblasts. Because curcumin, an extract from Curcuma longa, was recently found to reduce the formation of fibrous tissue, it is hypothesized that loading curcumin on implant surfaces would be efficacious in inhibiting fibrous encapsulation without adversely affecting the osteoblast functions. To prove this hypothesis, curcumin was loaded on to a titanium surface using poly(dopamine) as an anchor, and the behaviors of fibroblasts and osteoblasts on these curcumin-modified surfaces were investigated. Curcumin was successfully loaded on to titanium and showed a low release after incubation in phosphate-buffered saline for seven days. On the curcumin-modified surfaces, fibroblast proliferation was suppressed, and fibrous marker expressions as well as collagen synthesis were significantly reduced. These reductions were possibly because of the enhancement of fibroblast apoptosis induced by the surface curcumin. In contrast, no significant reduction in osteoblast functions was observed on the curcumin-modified substrates. These findings may provide a promising solution to reduce fibrous encapsulation, and thus may be highly beneficial for orthopaedic applications.