Dimeric guaianes from leaves of Xylopia vielana as snail inhibitors identified by high content screening.

The transcriptional repressor Snail trriggers epithelial-mesenchymal transition (EMT), the process allowing cancer cells with invasive and metastasis properties. In this study, we screened medicinal plants for the Snail inhibitory active components by high content screen (HCS) and found that the crude extract of Xylopia vielana leaves showed potential activity. Subsequently, bioassay-guided isolation of the extract of Xylopia vielana was performed to obtain twenty-four dimeric guaianes (1-24), including 16 new analogues (1-5, 8-11, 13-15, 17, 18, 21, and 22). Their structures were elucidated by the comprehensive application of multiple spectroscopic methods. Compounds 1, 11, 12, and 16 were initially identified as the active compounds. Wound healing assay, transwell migration assay and western blot experiments verified that compounds 1 and 12 inhibited the expression of Snail in a concentration-dependent manner, and compound 12 was verified as a potent tumor migration inhibitory agent. This work showed a practical strategy for the discovery of new Snail inhibitors from natural products and provided potential insights for dimeric guaianes as anticancer lead compounds specifically targeting Snail protein.

Evaluating the effect of secretome of human amniotic mesenchymal stromal cells on apoptosis induction and epithelial-mesenchymal transition inhibition in LNCaP prostate cancer cells based on 2D and 3D cell culture models.

Prostate cancer (PCa) is the second most prevalent cancer in men worldwide. Most cases of death from PCa are due to metastasis. Early stages of metastasis are mediated by epithelial-mesenchymal transition (EMT) process through which cancer cells acquire motility and invasive characteristics. Thus, more potent and novel therapeutic strategies must be designed based on the inhibition of EMT or metastasis. Herein, we employ a co-culture system to evaluate the anti-EMT effects of human amniotic mesenchymal stromal cells (hAMSCs) on LNCaP PCa cells. The RNA of treated (sample) and untreated cancer cells (control) and whole-cell lysates of related cells were prepared and analysed through quantitative real-time polymerase chain reaction (qRT-PCR) and western blot, respectively. Based on the results, the expression of vimentin, Snail and Zeb1 in LNCaP cells decreased and the expression of E-cadherin increased after treatment with hAMSCs. Furthermore, induction of the cellular apoptosis in LNCaP cells was detected. The anti-cancer activity of conditioned medium from hAMSCs was shown using hanging drop technique (a 3D cell culture model). Our findings support the idea that stem cells can be considered as a novel therapeutic approach to inhibit prostate cancer cells. SIGNIFICANCE OF THE STUDY: The anti-tumour activity of hAMSCs on LNCaP prostate cancer cells using 2D and 3D cell culture models via induction of apoptosis, suppression of EMT process and down-regulation of EGFR was shown. The results of the present study support this idea that hAMSCs may be a potent therapeutic tool to suppress tumour growth in LNCaP prostate cancer cells.

SNAIL- and SLUG-induced side population phenotype of HCT116 human colorectal cancer cells and its regulation by BET inhibitors.

Epithelial-mesenchymal transition (EMT) is associated with cancer malignancies such as invasion, metastasis, and drug resistance. In this study, HCT116 human colorectal cancer cells were transduced with SLUG or SNAIL retroviruses, and EMT cells with mesenchymal morphology were established. The EMT cells showed a high invasive activity and resistance to several anticancer agents such as methotrexate, SN-38, and cisplatin. Furthermore, they contained about 1-10% side population (SP) cells that were not stained by Hoechst 33342. This SP phenotype was not stable; the isolated SP cells generated both SP and non-SP cells, suggesting a potential for differentiation. Gene expression analysis of SP cells suggested the alteration of genes that are involved in epigenetic changes. Therefore, we examined the effect of 74 epigenetic inhibitors, and found that two inhibitors, namely I-BET151 and bromosporine, targeting the bromodomain and extra-terminal motif (BET) proteins, decreased the ratio of SP cells to <50% compared with the control, without affecting the immediate efflux of Hoechst 33342 by transporters. In addition, compared with the parental cells, the EMT cells showed a higher sensitivity to I-BET151 and bromosporine. This study suggests that EMT development and SP phenotype can be independent events but both are regulated by BET inhibitors in SLUG- or SNAIL-transducted HCT116 cells.

Fibroblast growth factor 2 induces proliferation and fibrosis via SNAI1-mediated activation of CDK2 and ZEB1 in corneal endothelium.

Investigating stimulation of endogenous wound healing in corneal endothelial cells (CECs) may help address the global shortage of donor corneas by decreasing the number of transplants performed for blindness because of endothelial dysfunction. We previously reported that IL-1ß stimulation leads to fibroblast growth factor (FGF2) expression, enhancing migration and proliferation of mammalian CECs. However, FGF2 also promotes the endothelial-mesenchymal transition, which can lead to retrocorneal membrane formation and blindness. This prompted us to investigate downstream FGF2 signaling targets that could be manipulated to prevent retrocorneal membrane formation. FGF2 stimulation altered cell morphology and induced expression of mesenchymal transition marker genes such as snail family transcriptional repressor 1 (SNAI1), SNAI2, zinc finger E-box-binding homeobox 1 (ZEB1), and ZEB2 This, in turn, induced expression of fibronectin, vimentin, and type I collagen, and suppressed E-cadherin in CECs in vitro and ex vivo siRNA-mediated SNAI1 knockdown revealed that SNAI1 induces ZEB1 expression, in turn inducing expression of type I collagen, the major component of retrocorneal membranes, and of cyclin-dependent kinase 2 (CDK2) and cyclin E1, promoting cell proliferation. siRNA-mediated knockdown of SNAI1 or ZEB1, but not of CDK2, inhibited FGF2-dependent expression of fibronectin, vimentin, and type I collagen and of suppression of E-cadherin expression. We conclude that SNAI1 is a key regulator of FGF2-dependent mesenchymal transition in human ex vivo corneal endothelium, with ZEB1 regulating type I collagen expression and CDK2 regulating cell proliferation. These results suggest that SNAI1 promotes fibrosis and cell proliferation in human corneal endothelium through ZEB1 and CDK2.

Low-level overexpression of p53 promotes warfarin-induced calcification of porcine aortic valve interstitial cells by activating Slug gene transcription.

The most frequently used oral anti-coagulant warfarin has been implicated in inducing calcification of aortic valve interstitial cells (AVICs), whereas the mechanism is not fully understood. The low-level activation of p53 is found to be involved in osteogenic transdifferentiation and calcification of AVICs. Whether p53 participates in warfarin-induced AVIC calcification remains unknown. In this study, we investigated the role of low-level p53 overexpression in warfarin-induced porcine AVIC (pAVIC) calcification. Immunostaining, quantitative PCR, and Western blotting revealed that p53 was expressed in human and pAVICs and that p53 expression was slightly increased in calcific human aortic valves compared with non-calcific valves. Terminal deoxynucleotidyltransferase-mediated dUTP nick end labeling staining indicated that apoptosis slightly increased in calcific aortic valves than in non-calcific valves. Warfarin treatment led to a low-level increase of p53 mRNA and protein in both pAVICs and mouse aortic valves. Low-level overexpression of p53 in pAVICs via an adenovirus vector did not affect pAVIC apoptosis but promoted warfarin-induced calcium deposition and expression of osteogenic markers. shRNA-mediated p53 knockdown attenuated the pAVIC calcium deposition and osteogenic marker expression. Moreover, ChIP and luciferase assays showed that p53 was recruited to the slug promoter and activated slug expression in calcific pAVICs. Of note, overexpression of Slug increased osteogenic marker Runx2 expression, but not pAVIC calcium deposition, and Slug knockdown attenuated pAVIC calcification and p53-mediated pAVIC calcium deposition and expression of osteogenic markers. In conclusion, we found that p53 plays an important role in warfarin induced pAVIC calcification, and increased slug transcription by p53 is required for p53-mediated pAVIC calcification.

Chlorogenic acid inhibits osteosarcoma carcinogenesis via suppressing the STAT3/Snail pathway.

Chlorogenic acid (CA) is a polyphenol compound that possesses anticancer effects on several types of tumors. However, there are few previous studies concerning the protective effects of CA on osteosarcoma. The current study aimed to examine the toxicity of CA to osteosarcoma cells and to explore the potential mechanisms. Cell growth was evaluated using cell counting kit-8 assay and Western blot analysis of proliferating cell nuclear antigen (PCNA). Apoptosis was assessed by flow cytometry analysis using flow cytometry and caspase-3/7 activity assay. The expression changes of the signal transducer and activator of transcription 3 (STAT3)/Snail pathway were detected by Western blot analysis. We found that CA dose-dependently inhibited cell viability and PCNA expression in osteosarcoma cells. Meanwhile, CA treatment increased the apoptotic rate and caspase-3/7 activity in osteosarcoma cells in a concentration-dependent manner. We found that CA concentration-dependently inhibited the activation of the STAT3/Snail pathway in osteosarcoma cells. Inhibition of the STAT3/Snail pathway by si-STAT3 retarded the growth and induced apoptosis of osteosarcoma cells. Mechanistically, activation of the STAT3/Snail pathway by pcDNA-STAT3 reversed the effects of CA on osteosarcoma cell growth and apoptosis. In conclusion, CA inhibited osteosarcoma carcinogenesis by suppressing osteosarcoma cell growth and inducing apoptosis, which was involved in inactivation of the STAT3/Snail pathway. Therefore, our study suggested that CA might have good therapy prospects in osteosarcoma therapy.

Snail/FOXK1/Cyr61 Signaling Axis Regulates the Epithelial-Mesenchymal Transition and Metastasis in Colorectal Cancer.

BACKGROUND/AIMS: Metastasis is the primary cause of colorectal cancer (CRC)-related death. However, the molecular mechanisms underlying metastasis in CRC remain unclear. METHODS: We evaluated mRNA and protein expression levels by quantitative real-time reverse transcription PCR, western blotting, immunofluorescence, tissue microarrays, and immunohistochemistry assays. We also assessed the migration and invasion abilities of CRC cells in vitro by wound healing assays, invasion and migration assays, western blot analysis, and immunofluorescence. Tumor metastasis was evaluated in nude mice in vivo. RESULTS: A positive correlation was observed between the expression patterns of Forkhead box k1 (FOXK1) and Snail in CRC. Luciferase reporter and chromatin immunoprecipitation assays demonstrated that Snail directly bound to and activated the human FOXK1 gene promoter. Moreover, the Snail-FOXK1 axis promote epithelial mesenchymal transition (EMT)-mediated CRC cell invasion and metastasis. FOXK1 and Snail expression levels were correlated with tumor progression and served as significant predictors of overall survival in patients with CRC. Furthermore, overexpression of FOXK1 induced the EMT by upregulating the expression of cysteine-rich angiogenic inducer 61 (Cyr61). Luciferase assays showed that Cyr61 was a direct transcriptional target of FOXK1. Down regulation of Cyr61 decreased FOXK1-enhanced "CRC cell" migration, invasion, and metastasis. Additionally, FOXK1 expression was positively correlated with Cyr61 expression and was associated with poor prognosis. CONCLUSIONS: The Snail/FOXK1/Cyr61 signaling axis regulates the EMT and metastasis of CRC.

FSCN1 Promotes Epithelial-Mesenchymal Transition Through Increasing Snail1 in Ovarian Cancer Cells.

BACKGROUND/AIMS: Epithelial-mesenchymal transition (EMT) is one of the key mechanisms mediating cancer progression. Snail1 has a pivotal role in the regulation of EMT, involving the loss of E-cadherin and concomitant upregulation of vimentin, among other biomarkers. We have found FSCN1 promoted EMT in ovarian cancer cells, but the precise mechanism of FSCN1 in EMT process has not been clearly elucidated. METHODS: The levels of FSCN1 and snail1 were determined in epithelial ovarian cancer(EOC) specimen and in ovarian cancer cells by RT-qPCR. The changes of EMT makers and effects on snail1 by FSCN1 were examined by overexpression or depletion of FSCN1 in EOC cells by RT-qPCR and western blotting. The invasiveness of the FSCN1-modified EOC cells was examined in transwell assay. Co-immunoprecipitation (IP) was performed to detect the interaction between snail1 and FSCN1 in EOC cells. RESULTS: We found FSCN1 and snail1 significantly increased in EOC, and especially in EOC with metastasis. FSCN1 was positively correlated with snail1 expression at the cellular/histological levels. Moreover, we further showed that FSCN1 physiologically interacted with and increased the levels of snail1 to promote ovarian cancer cell EMT. CONCLUSION: FSCN1 promote EMT through snail1 in ovarian cancer cells. FSCN1 is an attractive novel target for inhibiting invasion and metastasis of EOC cells.

MicroRNA-30a Suppresses the Activation of Hepatic Stellate Cells by Inhibiting Epithelial-to-Mesenchymal Transition.

BACKGROUND/AIMS: The activation of hepatic stellate cells (HSCs) is considered as a pivotal event in liver fibrosis and epithelial-mesenchymal transition (EMT) process has been reported to be involved in HSC activation. It is known that microRNAs (miRNAs) play a pro-fibrotic or anti-fibrotic role in HSC activation. Recently, emerging studies show that miR-30a is down-regulated in human cancers and over-expression of miR-30a inhibits tumor growth and invasion via suppressing EMT process. However, whether miR-30a could regulate EMT process in HSC activation is still unclear. METHODS: miR-30a expression was quantified using real-time PCR in carbon tetrachloride (CCl4)-induced rat liver fibrosis, activated HSCs and patients with cirrhosis. Roles of miR-30a in liver fibrosis in vivo and in vitro were also analyzed. Luciferase activity assays were performed to examine the binding of miR-30a to the 3'-untranslated region of snail family transcriptional repressor 1 (Snai1). RESULTS: miR-30a was down-regulated in human cirrhotic tissues. In CCl4 rats, reduced miR-30a was found in fibrotic liver tissues as well as isolated HSCs. There was a significant reduction in miR-30a in primary HSCs during culture days. miR-30a over-expression resulted in the suppression of CCl4-induced liver fibrosis. Restoration of miR-30a led to the inhibition of HSC activation including cell proliferation, α-SMA and collagen expression. Notably, miR-30a inhibited EMT process, with a reduction in TGF-ß1 and Vimentin as well as an increase in GFAP and E-cadherin. miR-30a induced a significant reduction in Snai1 protein expression when compared with the control. Interestingly, Snail protein expression was increased during liver fibrosis, indicating that there may be a negative correlation between miR-30a level and Snai1 protein expression. Further studies demonstrated that Snai1 was a target of miR-30a. CONCLUSION: Our results suggest that miR-30a inhibits EMT process, at least in part, via reduction of Snai1, leading to the suppression of HSC activation in liver fibrosis.

Stabilization of Slug by NF-κB is Essential for TNF-α -Induced Migration and Epithelial-Mesenchymal Transition in Head and Neck Squamous Cell Carcinoma Cells.

BACKGROUND/AIMS: Slug protein, a transcription factor for the induction of epithelial-mesenchymal transition (EMT) and cancer cell invasion and metastasis, is frequently upregulated in human epithelial cancers. However, mutation of this gene in cancer is rare, and the mechanism of its dysregulation remains unknown, especially in head and neck squamous cell carcinoma (HNSCC). METHODS: We examined the role of TNF-α in the stabilization of Slug by immunoprecipitation-westernblot analysis. Migration of HNSCC cells with or without knockdown of Slug gene expression was assayed by a wound healing assay. Immunohistochemical staining analysis was used to measurement Slug levels in both normal and HNSCC tumor tissues. RESULTS: The inflammatory cytokine TNF-α stabilized Slug protein by inhibiting its ubiquitination through the NF-κB pathway. Inhibition of NF-κB or knockdown of p65 abrogated the TNF-α-induced stabilization of Slug. Knockdown of Slug expression inhibited cancer cell migration and EMT characteristics induced by TNF-α. Moreover, increased levels of Slug were found to correlate with lymph node metastasis and predict poor prognosis in patients with HNSCC. CONCLUSIONS: NF-κB-mediated stabilization of Slug underlies the inflammation-induced EMT and metastasis in HNSCC, which may serve as a therapeutic target for metastatic HNSCC.

Nintedanib inhibits TGF-ß-induced myofibroblast transdifferentiation in human Tenon's fibroblasts.

Purpose: This study aimed to investigate the effect of nintedanib on the conversion of human Tenon's fibroblasts (HTFs) into myofibroblasts and reveal the molecular mechanisms involved. Methods: Primary cultured HTFs were incubated with transforming growth factor ß1 (TGF-ß1) alone or combined with nintedanib, and cell proliferation and migration were measured by cell counting kit-8 (CCK8) and the scratch wound assay, respectively. HTF contractility was evaluated with a 3D collagen contraction assay. The mRNA and protein levels of α smooth muscle actin (α-SMA) and Snail and the phosphorylation levels of Smad2/3, p38 mitogen-activated protein kinase (p38MAPK), and extracellular signal-regulated kinase ½ (ERK1/2) were determined by quantitative reverse transcription polymerase chain reaction (RT-PCR), western blot, and immunofluorescence staining. Results: Nintedanib inhibited the proliferation and migration of HTFs in a dose-dependent manner. Furthermore, nintedanib prevented HTF myofibroblast differentiation via downregulation of mRNA and protein expression of α-SMA and Snail. A three-dimensional (3D) collagen gel contraction assay demonstrated that nintedanib effectively inhibits myofibroblast contraction induced by TGF-ß1. Mechanistically, we revealed that nintedanib reduces the TGF-ß1-induced phosphorylation of Smad2/3, p38MAPK, and ERK1/2, suggesting that nintedanib acts through both classic and nonclassic signaling pathways of TGF-ß1 to prevent HTF activation. Conclusions: Our study provides new evidence that nintedanib has potent antifibrotic effects in HTFs and suggests that it may be used as a potential therapeutic agent for subconjunctival fibrosis.

Parthenolide attenuated bleomycin-induced pulmonary fibrosis via the NF-κB/Snail signaling pathway.

BACKGROUND: Parthenolide (PTL) is a natural molecule isolated from Tanacetum parthenium that exhibits excellent anti-inflammatory and antitumor activities. Pulmonary fibrosis (PF), especially idiopathic pulmonary fibrosis (IPF), is a chronic lung disease that lacks a proven effective therapy. The present study evaluated the therapeutic effect of PTL on PF. METHODS: Serum-starved primary lung fibroblasts and HFL1 cells were treated with different doses of PTL, and cell viability and the migration rate were measured. Western blot analysis and a dual-luciferase assay were used to analyze the epithelial-mesenchymal transition (EMT)-related transcription factors influenced by PTL treatment in A549 cells and primary lung epithelial cells. Mice with bleomycin (BLM)-induced pulmonary fibrosis were treated with different doses of intragastric PTL, and pathological changes were evaluated using Hematoxylin-eosin (H&E) staining and immunohistochemical analysis. RESULTS: Our results demonstrated that PTL reduced the cell viability and migration rate of lung fibroblasts and inhibited the expression of EMT-related transcription factors in lung epithelial cells. In vivo studies demonstrated that PTL attenuated BLM-induced pulmonary fibrosis and improved the body weight and pathological changes of BLM-treated mice. We further demonstrated that PTL attenuated BLM-induced PF primarily via inhibition of the NF-κB/Snail signaling pathway. CONCLUSION: These findings suggest that PTL inhibits EMT and attenuates BLM-induced PF via the NF-κB/Snail signaling pathway. PTL is a worthwhile candidate compound for pulmonary fibrosis therapy.

MiR-30e Attenuates Isoproterenol-induced Cardiac Fibrosis Through Suppressing Snai1/TGF-ß Signaling.

BACKGROUND: MicroRNAs are a class of small RNA molecules that inhibit protein expression through either degradation of messenger RNA or interference with protein translation. Our previous work suggested an involvement of miR-30e in myocardial fibrosis; however, the exact role of miR-30e in the pathogenesis of cardiac fibrosis and the underlying mechanisms are not known. METHODS: Male Sprague Dawley rats were treated with isoproterenol (ISO) to induce cardiac remodeling and fibrosis and treated with either miR-30e agomir (AG) or antagomir and respective controls. The expression of miR-30e was evaluated by reverse transcription and quantitative polymerase chain reaction. Myocardial fibrosis was assessed by Masson's trichrome staining, and the level of oxidative stress and the expression of Snai1 and transforming growth factor-beta (TGF-ß) were detected using Western blots. RESULTS: A significant downregulation of miR-30e was found in the hearts of ISO-treated rats with cardiac fibrosis compared with nontreated controls. In vivo administration of miR-30e AG increased the survival of ISO-treated rats compared with AG-negative control administration, which was associated with reduced oxidative stress. We further identified Snai1 as a novel miR-30e target. Snai1 expression was significantly increased in hearts from ISO-treated rats, which coincided with decreased miR-30e expression and increased TGF-ß expression. An miR-30e putative target sequence was identified in the 3'-untranslated region (UTR) Snai1. In a reporter assay, miR-30e greatly suppressed the activity of wild-type 3'-UTR-fused luciferase reporter, but showed no significant effect with the mutated 3'-UTR-fused reporter. CONCLUSION: MiR-30e attenuated ISO-induced cardiac dysfunction and cardiac fibrosis in a rat cardiac remodeling model. Mechanistically, miR-30e suppressed Snai1/TGF-ß pathway which was involved in ISO-induced cardiac remodeling.

FOXA1 Induces E-Cadherin Expression at the Protein Level via Suppression of Slug in Epithelial Breast Cancer Cells.

Epithelial-to-mesenchymal transition (EMT) is an important process during embryonic development and tumor progression by which adherent epithelial cells acquire mesenchymal properties. Forkhead box protein A1 (FOXA1) is a transcriptional regulator preferentially expressed in epithelial breast cancer cells, and its expression is lost in mesenchymal breast cancer cells. However, the implication of this biased expression of FOXA1 in breast cancer is not fully understood. In this study, we analyzed the involvement of FOXA1 in EMT progression in breast cancer, and found that stable expression of FOXA1 in the mesenchymal breast cancer MDA-MB-231 cells strongly induced the epithelial marker E-cadherin at the mRNA and protein levels. Furthermore, stable expression of FOXA1 was found to reduce the mRNA and protein expression of Slug, a repressor of E-cadherin expression. FOXA1 knockdown in the epithelial breast cancer MCF7 cells reduced E-cadherin protein expression without decreasing its mRNA expression. In addition, FOXA1 knockdown in MCF7 cells up-regulated Slug mRNA and protein expression. Notably, similar to FOXA1 knockdown, stable expression of Slug in MCF7 cells reduced E-cadherin protein expression without decreasing its mRNA expression. Taken together, these results suggest that although FOXA1 can induce E-cadherin mRNA expression, it preferentially promotes E-cadherin expression at the protein level by suppressing Slug expression in epithelial breast cancer, and that the balance of this FOXA1-Slug axis regulates EMT progression.

MiR-630 inhibits invasion and metastasis in esophageal squamous cell carcinoma.

Esophageal squamous cell carcinoma (ESCC) is among the most aggressive malignancies and has a high incidence in China. MicroRNAs (miRNAs) are small endogenous RNAs that regulate multiple tumorigenic processes, including proliferation, invasion, metastasis and prognosis. Using miRNA expression profiling analysis, we found that miR-630 was markedly down-regulated in three ESCC tissue samples compared with that in paired normal esophageal tissues. Differential miR-630 expression was subsequently confirmed using quantitative real-time PCR. To determine whether miR-630 down-regulation could be considered as a diagnostic indicator and adverse prognostic factor, we investigated the association between miR-630 and clinicopathological characteristics in patients with ESCC. It was found that decreased miR-630 expression was associated with poor overall survival in these patients. In addition, we also explored the biological function of miR-630 by targeting Slug and investigated the correlation between miR-630 expression and epithelial-mesenchymal transition (EMT) progression in vivo and in vitro Ectopic miR-630 expression could inhibit proliferation, invasion and metastasis, whereas miR-630 knockdown induced proliferation, invasion, metastasis and EMT traits. Overall, our study supports a role for miR-630 as a critical novel modulator in ESCC.

Microenvironmental Snail1-induced immunosuppression promotes melanoma growth.

Melanoma is an aggressive form of skin cancer due to its high metastatic abilities and resistance to therapies. Melanoma cells reside in a heterogeneous tumour microenvironment that acts as a crucial regulator of its progression. Snail1 is an epithelial-to-mesenchymal transition transcription factor expressed during development and reactivated in pathological situations including fibrosis and cancer. In this work, we show that Snail1 is activated in the melanoma microenvironment, particularly in fibroblasts. Analysis of mouse models that allow stromal Snail1 depletion and therapeutic Snail1 blockade indicate that targeting Snail1 in the tumour microenvironment decreases melanoma growth and lung metastatic burden, extending mice survival. Transcriptomic analysis of melanoma-associated fibroblasts and analysis of the tumours indicate that stromal Snail1 induces melanoma growth by promoting an immunosuppressive microenvironment and a decrease in anti-tumour immunity. This study unveils a novel role of Snail1 in melanoma biology and supports its potential as a therapeutic target.

Bioactivity descriptors for uncharacterized chemical compounds.

Chemical descriptors encode the physicochemical and structural properties of small molecules, and they are at the core of chemoinformatics. The broad release of bioactivity data has prompted enriched representations of compounds, reaching beyond chemical structures and capturing their known biological properties. Unfortunately, bioactivity descriptors are not available for most small molecules, which limits their applicability to a few thousand well characterized compounds. Here we present a collection of deep neural networks able to infer bioactivity signatures for any compound of interest, even when little or no experimental information is available for them. Our signaturizers relate to bioactivities of 25 different types (including target profiles, cellular response and clinical outcomes) and can be used as drop-in replacements for chemical descriptors in day-to-day chemoinformatics tasks. Indeed, we illustrate how inferred bioactivity signatures are useful to navigate the chemical space in a biologically relevant manner, unveiling higher-order organization in natural product collections, and to enrich mostly uncharacterized chemical libraries for activity against the drug-orphan target Snail1. Moreover, we implement a battery of signature-activity relationship (SigAR) models and show a substantial improvement in performance, with respect to chemistry-based classifiers, across a series of biophysics and physiology activity prediction benchmarks.

Caffeine prevents oxalate-induced epithelial-mesenchymal transition of renal tubular cells by its anti-oxidative property through activation of Nrf2 signaling and suppression of Snail1 transcription factor.

Caffeine is an active ingredient found in coffee and energy beverages. Its hepatoprotective effects against liver fibrosis are well-documented. Nonetheless, its renoprotective effects against renal fibrogenesis and epithelial-mesenchymal transition (EMT) processes remain unclear and under-investigated. In this study, the protective effects of caffeine against oxalate-induced EMT in renal tubular cells were evaluated by various assays to measure expression levels of epithelial and mesenchymal markers, cell migrating activity, level of oxidized proteins, and expression of Nrf2 and Snail1. Oxalate at sublethal dose significantly suppressed cell proliferation but increased cell elongation, spindle index and migration. Oxalate also decreased expression of epithelial markers (zonula occludens-1 (ZO-1) and E-cadherin) but increased expression of mesenchymal markers (fibronectin, vimentin and α-smooth muscle actin (α-SMA)). All of these EMT-inducing effects of oxalate could be prevented by pretreatment with caffeine. While oxalate increased oxidized proteins and Snail1 levels, it decreased Nrf2 expression. Caffeine could preserve all these molecules to their basal (control) levels. Finally, silencing of Nrf2 expression by small interfering RNA (siRNA) could abolish such protective effects of caffeine on oxalate-induced EMT. Our data indicate that the renoprotective effects of caffeine against oxalate-induced EMT is mediated, at least in part, by its anti-oxidative property through activation of Nrf2 signaling and suppression of Snail1 transcription factor.

Parthenolide inhibits the tumor characteristics of renal cell carcinoma.

Parthenolide has been demonstrated to have anticancer effects against various types of cancer. However, the functional role of parthenolid has yet to be clearly reported in renal cell carcinoma (RCC). The aim of the present study was to investigate the effect of parthenolide in RCC 786­O and ACHN cells. CCK­8 and colony­formation assays were used to observe the proliferation of RCC 786­O and ACHN cells. Migration and invasion abilities were assessed through Transwell assays. The stem cell­like properties of RCC cell lines were evaluated by mammosphere formation assay. Western blot analysis was used to investigate the metastasis and epithelial­mesenchymal transition (EMT) induced by parthenolide on the expression levels of MMP2, MMP9, E­cadherin, N­cadherin, vimentin and snail. The results revealed that when the cells were treated with various concentrations of parthenolide, the rate of proliferation and growth was decreased in 786­O and ACHN cells. The number of invasive cells in a field was approximately 170, 90, 40 and 190, 150, 70 in 786­O and ACHN cells with 0, 4 and 8 µM of parthenolide treatment. MMP­2/­9 expression (P<0.05) was inhibited by parthenolide. The protein levels of E­cadherin were increased (P<0.05) and N­cadherin, vimentin and snail were decreased (P<0.05) by parthenolide treatment. In addition, Parthenolide inhibited the expression of cancer stem cell markers and the PI3K/AKT pathway. The present study confirmed that parthenolide inhibited RCC cell proliferation and metastasis and suppressed the stem cell­like properties of RCC cell lines, which could be a potential strategy to treat RCC. However, further molecular mechanisms of parthenolide in RCC should be observed and reported in the future.

CD24 gene inhibition and TIMP-4 gene upregulation by Imperata cylindrica's root extract prevents metastasis of CaSki cells via inhibiting PI3K/Akt/snail signaling pathway and blocking EMT.

ETHNOPHARMACOLOGICAL RELEVANCE: Imperata cylindrica (L.) Raeusch (Gramineae) is a medicinal spice traditionally used in the treatment of hypertension and cancer. AIM OF THE STUDY: To assess the anti-metastatic potential of the methanol extract of I. cylindrica roots and determined its mechanisms of action. MATERIAL AND METHODS: The growth inhibition activity of I. cylindrica root extract in vitro and in vivo in human cervical cancer. The scratch assay and Boyden Chamber assay were used to determine the anti-migrative and anti-invasion actions of the plant extract. The whole-genome gene expression profiling using RNA-Seq was performed to determine the differentially expressed genes in CaSki cells after exposure to I. cylindrica to identify its targeted genes related to metastasis. Using protein analysis (western blotting) and gene expression analysis (RTqPCR), the targeted pathways of the key genes that were initially identified with RNA-Seq, were evaluated. RESULTS: I. cylindrica extract showed dose-dependent cytotoxicity in vitro and in vivo in mice bearing tumors. Furthermore, I. cylindrica root extract significantly inhibited cell migration and cell invasion. After the genome-wide transcriptome analysis, we found that important genes involved in cancer progression and metastasis of cervical cancer, that is, CD24 and TIMP-4 were significantly downregulated and upregulated, respectively. Moreover, I. cylindrica root extract significantly inhibited the PI3/AKT/Snail signaling pathway and blocked the EMT of CaSki cells. CONCLUSION: These findings provide an anti-metastatic mechanism of action of I. cylindrica root extract toward the human cervical cancer suggesting that this plant maybe developed into selective chemotherapy.