Snail Protein Research Articles

TMEM17 promotes malignant progression of breast cancer via AKT/GSK3β signaling.

PurposeCurrent knowledge of TMEM17, a recently identified protein of the transmembrane (TMEM) family, is limited, especially with respect to its expression and biological functions in malignant tumors. This study analyzed TMEM17 expression in invasive breast cancer tissue and breast cell lines and its relevance to clinicopathological factors, and investigated the mechanisms underlying the biological effects of TMEM17 on breast cancer cells.Patients and methodsTMEM17 protein expression was determined in 20 freshly harvested specimens (tumor and paired normal tissues) by Western blotting. Immunohistochemical analysis was performed to determine the expression and subcellular localization of TMEM17 in samples from 167 patients (mean age, 49 years) diagnosed with invasive ductal carcinoma (38 with triple-negative breast cancer; 129 with non-triple-negative breast cancer) who underwent complete resection in the First Affiliated Hospital of China Medical University between 2011 and 2013. Furthermore, TMEM17 was knocked down by small interfering RNAs in breast cancer cell lines.ResultsTMEM17 was found to be significantly upregulated in breast cancer tissues compared to the corresponding normal breast tissues by Western blotting (p=0.015). Immunohistochemical analysis revealed that TMEM was significantly upregulated in invasive breast cancer cells compared to adjacent normal breast duct glandular epithelial cells (10.78% vs 76.05%, p<0.001), and its expression was closely related to the patient’s T-stage (p=0.022), advanced TNM stages (p=0.007), and lymph node metastasis (p=0.012). After TMEM17 knockdown or overexpression in breast cancer cell lines, TMEM17 upregulated p-AKT, p-GSK3β, active β-catenin, and Snail, and downstream target proteins c-myc and cyclin D1, and downregulated E-cadherin, resulting in increased cancer cell proliferation, invasion, and migration. These effects were reversed by the AKT inhibitor LY294002.ConclusionOur results indicate that TMEM17 is upregulated in breast cancer tissues and can promote malignant progression of breast cancer cells by activating the AKT/GSK3β signaling pathway.

Snail-1 Silencing by siRNA Inhibits Migration of TE-8 Esophageal Cancer Cells Through Downregulation of Metastasis-Related Genes.

Purpose: Snail-1 is a transcription factor, which takes part in EMT, a process related to the emergence of invasion and cancer progression. The purpose of this study was to evaluate the effect of Snail-1 silencing on the human esophageal squamous cell carcinoma cell line, namely TE-8, in vitro.Methods: In this study, transfection of Snail-1 specific siRNA was conducted into TE-8 cells. The relative mRNA expression levels of Snail-1, Vimentin, CXCR4 and MMP-9 and transcription levels of miR-34a and let-7a were investigated by quantitative Real-time PCR. Western blotting was carried out to evaluate the Snail-1 protein level. Migration assay of TE-8 cells was also performed following the presence or absence of Snail-1 specific siRNA. MTT and TUNEL assays were performed to evaluate cell viability after Snail-1 silencing.Results: It was found that treatment of cancer cells with the Snail-specific siRNA effectively downregulated the expression of Snail-1 in both mRNA and protein levels, and vimentin, CXCR4, and MMP-9 in mRNA level. However, it elevated the transcript levels of miR-34a and let-7a expressions. Furthermore, transfection of cancer cells with the Snail-specific siRNA significantly induced apoptosis in TE8 cells. Moreover, suppression of Snail-1 led to diminished cell migration.Conclusion: It seems that Snail-specific siRNA can significantly interrupt esophageal cancer cell migration and reduce metastatic-related factors and induce miR-34a and let-7a in vitro. The bottom line is that therapeutic approaches via targeting Snail-1 can be used for ESCC treatment, suggesting that other possible target molecules for ESCC therapy require to be explored.

Radiation-Induced Pulmonary Epithelial-Mesenchymal Transition: A Review on Targeting Molecular Pathways and Mediators.

Radiotherapy is the most widely used treatment method for average and advanced lung cancer patients. Moreover, the clinical toxicities caused by radiotherapy are categorized into acute radiation pneumonitis and late pulmonary fibrosis. Epithelial-mesenchymal transition (EMT) is a complex physiological process involves many signaling molecules and proteins like adaptor proteins, and transcriptional factors. It was identified as a significant mechanism for fibrosis, wound healing and also cancer. A variety of biomarkers have appeared in radiation-induced lung EMT, some of which are acquired (N-cadherin, vimentin and fibronectin, etc.) and some of which are repressed during the transition of epithelial cells (E-cadherin, zona occludens-1). In the current review, we highlighted the radiation-induced lung EMT signaling pathway and their mediators. We also discuss the EMT in cancer, fibrosis and its epigentics. Radiation-induced lung EMT is controlled by numerous signaling pathways like MAPK, NF-kB, Wnt, microRNAs and histone modifications. Transcriptional factors such as Snail, slug, twist, ZEB1 (Zinc finger E-box binding-1) and ZEB2 (Zinc finger E-box binding-2) proteins are inducers linking radiation-induced EMT and fibrosis. Epigenetic modulations are heritable changes in the structure and function of the genome that occurs without any change in the sequence. Several approaches showed the role of epigenetic modifications and its inhibitors in controlling fibrosis and cancer. Only limited reports are focused on understanding the epigenetic regulations of radiation-induced lung EMT. The current review focused on recent findings regarding radiation-induced lung fibrosis and EMT, thus provides some information on important signaling pathways, its subsequent expression of genes and proteins involved in EMT. This review also discussed various inhibitors that could be used to treat EMT related diseases, i.e., fibrosis, cancer.

Combating head and neck cancer metastases by targeting Src using multifunctional nanoparticle-based saracatinib

BackgroundInhibition of metastasis of head and neck squamous cell carcinoma (HNSCC) is one of the most important challenges in cancer treatment. Src, a non-receptor tyrosine kinase, has been implicated as a key promoter in tumor progression and metastasis of HNSCC. However, Src therapy for HNSCC is limited by lack of efficient in vivo delivery and underlying mechanisms remain elusive.MethodsSrc knockdown cells were achieved by lentiviral-mediated interference. Cell migration and invasion were examined by wound healing and Transwell assays. Protein levels were determined by Western blot and/or immunohistochemistry. The Src inhibitor saracatinib was loaded into self-assembling nanoparticles by the solvent evaporation method. An experimental metastasis mouse model was generated to investigate the drug efficacy in metastasis.ResultsBlockade of Src kinase activity by saracatinib effectively suppressed invasion and metastasis of HNSCC. Mechanistic assessment of the drug effects in HNSCC cells showed that saracatinib induced suppression of Src-dependent invasion/metastasis through downregulating the expression levels of Vimentin and Snail proteins. In tests in mice, saracatinib loaded into the novel multifunctional nanoparticles exhibited superior effects on suppression of HNSCC metastasis compared with the free drug, which is mainly attributed to highly specific and efficient tumor-targeted drug delivery system.ConclusionsThese findings and advances are of great importance to the development of Src-targeted nanomedicine as a more effective therapy for metastatic HNSCC.

Subcellular localization and expression of E-cadherin and SNAIL are relevant since early stages of oral carcinogenesis

The biological process of epithelial-to-mesenchymal transition (EMT) has been studied in oral squamous cell carcinoma (OSCC) metastasis, but it is rarely evaluated at several stages of oral carcinogenesis. This study aimed to analyze the presence of SNAIL and E-cadherin proteins, markers of EMT, in the development and progression of OSCC, evaluating excised specimens of potentially malignant lesions (oral leukoplakia with and without dysplasia-OL and OLD, respectively), tumor tissues (OSCC), metastatic lymph nodes (LN), and normal oral mucosa (NOM) by immunohistochemistry, considering subcellular localization. Additionally, SNAIL and E-cadherin transcripts were evaluated in vitro by qPCR, using SCC-9 cell line in comparison to human keratinocytes (HPEC). There was a significant increase in nuclear expression of SNAIL from NOM to OLD followed by a noticeable decrease in nuclear expression accompanied by increased cytoplasmic expression in OSCC (p<0.05). The E-cadherin cytoplasmic expression was remarkable and statistically significant higher in OSCC and LN, both compared to NOM (p< 0.0001), OL (p<0.01) and OLD (p< 0.0001 and p<0.001, respectively). In vitro, E-cadherin and SNAIL transcripts were lower in SCC-9 compared to HPEC cells, although only the decrease of E-cadherin was statistically significant (p<0.05). Regarding the association of E-cadherin and SNAIL expression with the clinical findings, the analysis revealed an association between the cytoplasmic expression of SNAIL and the invasion pattern (p=0.05) in OSCC. The increased nuclear SNAIL expression may be characteristic of OLD, and the presence of E-cadherin in cell cytoplasm a marker of transformation to malignancy of potentially malignant oral leukoplakias into OSCC.

3,6-dihydroxyflavone suppresses the epithelial-mesenchymal transition, migration and invasion in endometrial stromal cells by inhibiting the Notch signaling pathway.

Endometriosis is a common disease in women of reproductive age. Characteristics of endometriosis include invasion, metastasis, and recurrence, which are similar to those of malignant tumors. However, the etiology and pathogenesis of endometriosis are still not clear. This study aims to explore the mechanism of 3,6-dihydroxyflavone (3,6-DHF) in the development of endometriosis. Primary cultured ovarian ectopic endometrial stromal cells (OvESCs) were utilized as the in vitro model of endometriosis. OvESCs were treated with different concentrations of 3,6-DHF. The expressions of proteins related to epithelial-mesenchymal transition (EMT) and Notch signal pathway were detected by Western blot. The mRNA expressions of related genes were detected by quantitative Real-Time Polymerase Chain Reaction (qRT-PCR). The viability of treated cells was detected by transwell assay. The impact of 3,6-DHF on ectopic lesions was explored after the animal model of endometriosis was successfully established. With the increased concentration of 3,6-DHF in OvESCs, the protein and mRNA expressions of E-cadherin were gradually increased, while the protein and mRNA expressions of N-cadherin, Twist, Snail, and Slug were decreased. 3,6-DHF treatment inhibited the migration and invasion ability of OvESCs in a dose-dependent manner. In the endometriosis model of severe combined immunodeficient (SCID) mice, lesions in the 3,6-DHF treated group were significantly smaller than those of the control group. The same changes were found in the endometriosis model of Sprague Dawley (SD) rats. Protein expressions of Notch1, NICD, and Hes-1 in OvESCs were inhibited by 3,6-DHF in a dose-dependent manner. 3,6-DHF can inhibit the binding of NICD-CSL-MAML complex in OvESCs, thereby inhibiting the expressions of proteins related to Notch signaling pathway in vitro. 3,6-DHF can inhibit the development of EMT, migration, and invasion of endometrial stromal cells by inhibiting the Notch signaling pathway.

TRIM50 suppressed hepatocarcinoma progression through directly targeting SNAIL for ubiquitous degradation

Tripartite motif-containing 50 (TRIM50) belongs to the tripartite motif (TRIM) protein family, which has been implicated in the pathogenesis of multiple cancers. However, the role of TRIM50 in hepatocellular carcinoma (HCC) remains to be clarified. Here we showed that TRIM50 expression was significantly decreased in liver cancer tissues compared with corresponding non-cancerous liver tissues, and its decreased expression was significantly correlated with advanced disease progression. Gain-of-function assay by exogenous overexpression of TRIM50 in HCC cells showed that proliferation, colony formation, migration and invasion of HCC cells were significantly inhibited, whereas loss-of-function assay by TRIM50 knockdown showed that these malignant behaviors of HCC cells were significantly increased. Further investigation showed that TRIM50 could directly bind with SNAIL and induced K-48 linked poly-ubiquitous degradation of SNAIL protein, which further reversed SNAIL-mediated epithelial-to-mesenchymal transition (EMT) process of HCC cells. In vivo assay by xenograft tumor model verified the antitumor effect of TRIM50 on HCC. Taken together, these results showed that TRIM50 acted as a tumor suppressor in HCC cells by directly targeting SNAIL and reversing EMT, which further indicated that positive modulation of TRIM50 might be a novel therapeutic strategy for SNAIL overexpressed HCC cells.

Genomewide binding of transcription factor Snail1 in triple-negative breast cancer cells.

Transcriptional regulation mediated by the zinc finger protein Snail1 controls early embryogenesis. By binding to the epithelial tumor suppressor CDH1 gene, Snail1 initiates the epithelial–mesenchymal transition (EMT). The EMT generates stem‐like cells and promotes invasiveness during cancer progression. Accordingly, Snail1 mRNA and protein is abundantly expressed in triple‐negative breast cancers with enhanced metastatic potential and phenotypic signs of the EMT. Such high endogenous Snail1 protein levels permit quantitative chromatin immunoprecipitation‐sequencing (ChIP‐seq) analysis. Snail1 associated with 185 genes at cis regulatory regions in the Hs578T triple‐negative breast cancer cell model. These genes include morphogenetic regulators and signaling components that control polarized differentiation. Using the CRISPR/Cas9 system in Hs578T cells, a double deletion of 10 bp each was engineered into the first exon and into the second exon–intron junction of Snail1, suppressing Snail1 expression and causing misregulation of several hundred genes. Specific attention to regulators of chromatin organization provides a possible link to new phenotypes uncovered by the Snail1 loss‐of‐function mutation. On the other hand, genetic inactivation of Snail1 was not sufficient to establish a full epithelial transition to these tumor cells. Thus, Snail1 contributes to the malignant phenotype of breast cancer cells via diverse new mechanisms.

Downregulation of HOXA13 sensitizes human esophageal squamous cell carcinoma to chemotherapy.

BackgroundChemoresistance often develops in esophageal squamous cell carcinoma (ESCC), leading to poor prognosis. HOX genes play a crucial role in embryonic development and cell differentiation. Studies have recently linked HOX with chemoresistance, thus we explored whether HOXA13 is involved in ESCC chemoresistance.MethodsOne hundred thirty‐one ESCC patients who received neoadjuvant chemotherapy were enrolled. HOXA13 expression was examined by immunohistochemistry. RNA interference was used to knock down the HOXA13 expression in KYSE70 and transfected HOXA13 plasmid to overexpress HOXA13 in KYSE510 cells. We examined half‐maximal inhibitory concentration of cisplatin, apoptosis, and epithelial‐to‐mesenchymal transition (EMT) in ESCC cell lines with different HOXA13 expression levels by cell counting kit‐8, flow cytometry, and transwell analysis.ResultsThe median survival of patients with high HOXA13 expression was significantly shorter than those with low expression (P = 0.027). HOXA13 was associated with worse tumor regression grade (P = 0.009). Low HOXA13 expressed cells decreased the half‐maximal inhibitory concentration of cisplatin (P < 0.05), increased cisplatin‐induced apoptosis (P < 0.05), and decreased EMT (P < 0.05) compared with high HOXA13 expressed cells. In low HOXA13 expressed cells, cleaved caspase‐3 and cleaved PARP expression induced by cisplatin increased, while expression of E‐cadherin and Snail protein, markers of EMT, was upregulated and downregulated, respectively. EMT decreased in low HOXA13 expressed cells.ConclusionHigh HOXA13 expression was associated with inferior tumor regression grade and poor overall survival in ESCC patients treated with neoadjuvant chemotherapy. HOXA13 increased cisplatin‐resistance and promoted EMT in ESCC cells.

LKB1 obliterates Snail stability and inhibits pancreatic cancer metastasis in response to metformin treatment.

Metastasis to distant organs is a particularly ominous feature of malignant cancer. LKB1 (also known as STK11) has been identified as a tumor suppressor in several types of cancers. Here, we show that LKB1 is at low levels and is negatively associated with poor clinical outcomes in pancreatic cancer (PC). LKB1 is inversely correlated with Snail protein in PC, in which the loss of LKB1 facilitates metastasis through elevating Snail protein level. Furthermore, LKB1 boosts Snail's interaction with E3 ligase FBXL14, leading to increasing ubiquitin‐mediated Snail degradation. Notably, metformin could increase Snail protein ubiquitination via augmenting the location of LKB1 at cytoplasm as well as increasing LKB1 expression. Altogether, our data established that LKB1 impedes invasion and metastasis by decreasing the Snail protein level in PC. Targeting the LKB1/FBXL14/Snail axis may represent a promising therapeutic strategy and metformin might be beneficial for PC therapy through activating the LKB1‐mediated Snail ubiquitination pathway.

Clinical relevance of lysyl oxidase-like 2 and functional mechanisms in glioma.

IntroductionGlioma is the most frequent malignancy of the adult central nervous system with high recurrence risk and poor prognosis. Understanding the biological molecular mechanisms involved in glioma progression is critical for studying oncogenic mechanisms and improving prognosis. Lysyl oxidase-like 2 (LOXL2) is a kind of lysyl oxidase catalyzing the formation of peptidyl-lysine residues and promoting intramolecular cross-linking, especially for proteins in extracellular matrix. Our study explored the expression pattern of LOXL2 in glioma for the first time and found that its high expression was associated with larger tumor size and advanced tumor grade (P<0.05). Moreover, univariate and multivariate analyses revealed LOXL2 as a novel independent prognostic factor for the overall survival of glioma patients.MethodsTo evaluate the detailed functional roles of LOXL2, we tested its oncobiology characteristics in U87-MG cells with overexpression and knockdown experiments.ResultsCellular results demonstrated that LOXL2 overexpression enhanced cell proliferation and invasion, while LOXL2-siRNA attenuated cell viability. Furthermore, our data identified the participation of E-cadherin, Snail1, Src, and FAK proteins downstream of LOXL2. Notably, by using immunoprecipitation and mass spectrometry strategies, we initially verified the interaction between LOXL2 and HDAC2, indicating the existence of a protein complex containing LOXL2/Snail1/HDAC2. Additionally, the expression of HDAC2 protein was highly correlated with that of LOXL2 in clinical glioma tissues (P=0.02), further implying the synergic oncogenic roles of these 2 proteins.ConclusionLOXL2 is a promising prognostic biomarker and may be further evaluated as a potential drug target for patients with glioma.

Post-transcription mediated Snail stabilization is involved in radiation exposure induced invasion and migration of hepatocarcinoma cells

Increasing evidences suggested that radiotherapy can paradoxically promote tumor invasion and metastatic processes, while its detailed mechanism is not well illustrated. Our present study found that radiation can promote the migration and invasion of hepatocellular carcinoma (HCC) cells via induction of epithelial mesenchymal transition (EMT), which was evidenced by the results that radiation induced up regulation of vimentin while down regulation of E-Cadherin. As to the EMT-related transcription factors, radiation increased the expression of Snail, while not Slug, ZEB1 or TWIST. This was confirmed by the results that radiation increased the nuclear translocation of Snail in HCC cells. However, radiation had no effect on the expression or half-life of Snail mRNA. In HCC cells treated by cycloheximide (CHX, the translation inhibitor), radiation significantly increased the half-life of Snail protein, which suggested that radiation increased the expression of Snail via up regulation of its protein stability. Radiation increased the expression of COP9 signalosome 2 (CSN2), which has been reported to block the ubiquitination and degradation of Snail. Silence of CSN2/Snail can attenuate radiation induced cell migration and EMT of HCC cells. Collectively, our data suggested that radiation can promote HCC cell invasion and EMT by stabilization of Snail via CSN2 signals.

Changes in trophoblasts gene expression in response to perchlorate exposition

Contaminated water with chlorates is a public health problem associated with iodine deficiency. Epidemiological evidence shows that iodine deficiency is a risk factor for preeclampsia (PE). In this study we use human BeWo trophoblast cells exposed to perchlorate (KClO4) and changes in gene expression were analyzed by microarrays, quantitative RT-PCR (qRT-PCR) and immunoblot. The microarray analysis identified 48 transcripts up-regulated and 112 down-regulated in comparison with non-exposed trophoblast. The qRT-PCR analysis confirmed changes in GAS7, PKP2, Emilin, Dynatic 3, protocadherins 11, 15, gamma A12, EGFR, SAFB1, ACE2, ANXA2, Apoliprotein E, SREBF1, and C/EBP-β. KClO4 exposition decreased the mRNA and protein of C/EBP-β and GPX4. Also, we observed a nuclear translocation of HIF1α protein, and increase in both Snail and ACE2 protein by immunoblot. These effects were accompanied by an increases in ROS and nitric oxide. In conclusion, our results show that exposure to KClO4 alters genes involved in migration, adhesion, differentiation, and correlate with the increase of oxidative stress and nitric oxide production in trophoblast cells. It is possible that iodine deficiency is associated with these processes. However, further studies are required to corroborate the role of iodine in trophoblast cells.

Nur77 suppression facilitates androgen deprivation-induced cell invasion of prostate cancer cells mediated by TGF-β signaling.

Androgen deprivation therapy (ADT) remains a standard treatment for advanced prostate cancers. However, recent studies revealed that while inhibiting the growth of certain types of prostate cancer cells, ADT promotes invasion. In the current study, we explored the effects of Nur77, an orphan nuclear receptor, on prostate cancer cell invasion following ADT. Androgen receptor (AR) and Nur77 protein expression in patient tissues and cell lines were quantified via ELISA and western blot. The effects of AR-signaling on Nur77 expression were examined. The effects of Nur77 over-expression and knockdown on ADT-induced prostate cancer cell invasion were characterized. The results showed that AR and Nur77 are both highly expressed in prostate cancers of patients. Nur77 is positively regulated by AR-signaling at transcriptional level in NCI-H660, a widely used prostate cancer cell line. AR antagonists, Casodex and MDV3100 treatment resulted in significant inhibition of prostate cancer cell growth but enhanced cancer cell invasion. Nur77 over-expression blocked invasion-promoting effect of ADT, which is consistent with the down-regulation of MMP9 and Snail protein expression. Further mechanistic investigations showed that Nur77 inhibited transcription of TGF-β target genes (Snail and MMP9), and thereby inhibits TGF-β-mediated prostate cancer cell invasion following androgen antagonism. In addition, our data suggested the nature of this inhibitory effect of Nur77 on TGF-β-signaling is selective, for Smad3-signaling, the classical effector of TGF-β-signaling, was not interrupted by Nur77 over-expression. Considering the limited success of management of prostate cancer metastasis following ADT, our data strongly suggest that Nur77 regulation could be a promising direction for search of complementary therapeutic strategy on top of classic ADT therapy.

OTUB1 promotes esophageal squamous cell carcinoma metastasis through modulating Snail stability.

Snail is a key regulator of epithelial-mesenchymal transition (EMT) and plays an important role in tumor progression and metastasis. Snail is rapidly degraded in the cells and its protein level is critically controlled. Although several E3 ligases regulating Snail degradation have been defined, the deubiquitinases (DUBs) responsible for Snail deubiquitination are less studied. We identified ovarian tumor domain-containing ubiquitin aldehyde binding protein 1 (OTUB1) as a DUB that stabilizes Snail through preventing its ubiquitination and proteasomal degradation. Functionally, OTUB1 facilitates metastasis of esophageal squamous cell carcinoma (ESCC) through promoting Snail protein stability. Moreover, OTUB1 is highly expressed in ESCC and higher expression of OTUB1 predicts poor prognosis. These findings suggest that OTUB1 is an essential regulator of Snail and plays a critical role in facilitating esophageal cancer progression.

Snail immunohistochemical overexpression correlates to recurrence risk in non-muscle invasive bladder cancer: results from a longitudinal cohort study.

The current WHO/ISUP classification and grading system subdivides urothelial tumours into prognostically distinct categories. Understanding the molecular pathways involved in bladder cancer development can improve patient stratification and management. This study aims to investigate the relationship between Snail, Slug and E-cadherin expressions and clinico-pathological features of non-muscle invasive bladder carcinoma (NMIBC). All patients attending the same urological centre from January to May 2002, who were pathologically diagnosed with NMIBC, were enrolled in this longitudinal cohort study. E-cadherin, Snail and Slug protein expressions were assessed by immunohistochemical analysis and compared with follow-up data. The main outcome measures were recurrence and progression rates. The cohort under investigation included 43 patients (38 men and 5 women, mean age 67.7 ± 10.6years). High-grade (HG) carcinomas were 20/43, with 10 invasive cases (pT1). Low-grade (LG) carcinomas were 23/43, with no invasive cases (pTa). Among the eight HGpTa cases with recurrence, strong Snail expression was detected in six (75%). Out of the 17 LGpTa patients who experienced recurrence, 12 (70.6%) showed strong positivity for Snail. Among the 10 HGpT1 cases, recurrence was observed in 4, of which, 3 (75%) stained intensely for Snail. The Kaplan-Meier curves showed significantly different recurrence rates for patients with strong or weak Snail reactivity (p = 0.027). E-cadherin and Slug expression did not correlate with any of the parameters considered. On multivariate analysis, Snail expression was recognised as an independent prognostic factor for tumour recurrence (p = 0.003). In our study population, Snail immunohistochemical overexpression proved to be related to tumour recurrence in patients affected by NMIBC.

Small interference of transcription factor Snail contribute to enhanced cisplatin sensitivity on human laryngeal resistant cancer cells

Objective:To study the relationship between transcription factor Snail and the sensitivity of cisplatin on human laryngeal resistant cancer cells.Method:siRNA interference of Snail was transfected by small RNA interference technology. The interference efficiency on mRNA level were detected by RT-qPCR assay; the expression of Snail protein level was assessed by immunofluorescence. The inhibition ratio of different cisplatin concentration (0, 1, 2, 4, 8, 16 μg/ml) was detected by CCK-8 assay; the protein level of Snail, E-cadherin, MDR1were detected by Western blot assay.Result:RT-qPCR assay show the expression of Snail on mRNA level was decreased to (67.85±9.50)% after transfection in Hep-2/CDDP cell(P<0.05). Immunofluorescence show fluorescence intensity of si-Hep-2/CDDP group was reduced both in nucleus and cytoplasm; CCK-8 assay show the inhibitory ratio of transfected group was increased compared to negative control and Hep-2/CDDP group in different cisplatin concentration (0, 1, 2, 4, 8, 16 μg/ml) (P<0.05). Western blot assay show the protein expression of Snail and MDR1 were down-regulated in transfected Hep-2/CDDP cells (allP<0.05), while epithelial marker E-cadherin was up-regulated in protein level (P<0.05).Conclusion:Small interference of transcription factor Snail could increase the expression of E-cadherin while decrease the expression of MDR1, and it was confirmed that interference Snail contribute to enhanced cisplatin sensitivity on human laryngeal resistant cancer cells.

Upregulation of lactate-inducible snail protein suppresses oncogene-mediated senescence through p16INK4a inactivation

BackgroundThe preferential use of aerobic glycolysis by tumor cells lead to high accumulation of lactate in tumor microenvironment. Clinical evidence has linked elevated lactate concentration with cancer outcomes. However, the role and molecular mechanisms of lactate in cellular senescence and tumor progression remain elusive.MethodsThe function of Snail in lactate-induced EMT in lung cancer cells was explored by wound healing assay and cell invasion assay. The qRT-PCR and dual luciferase reporter assay were performed to investigate how lactate regulates Snail expression. The level of TGF-β1 in culture supernatant of cells was measured by ELISA for its correlation with extracellular levels of lactate. Ras activity assay and SA-β-gal activity assay were established to determine the effect of lactate on oncogene-induced senescence in human lung epithelial cells. ChIP assays were conducted to determine the binding of snail to p16INK4a promoter. Two TCGA data sets (TCGA-LUAD and TCGA-LUSC) were used to explore the correlations between SNAI1 and CDKN2A expression.ResultsIn this study, we showed the invasive and migratory potential of lung cancer cells was significantly enhanced by lactate and was directly linked to snail activity. We also demonstrated that extracellular acidification itself is a direct cause of the increased snail expression and physiologically coupled to LDHA-dependent conversion of pyruvate to lactate. Mechanistically, lactate exerts its central function in induction of snail and EMT by directly remodeling ECM and releasing activated TGF-β1. We also demonstrated that Snail help premalignant cells to escape the oncogene-induced senescence by directly targeting and inhibiting p16INK4a expression.ConclusionsOur study extends the understanding of EMT in tumorigenesis by uncovering the role of snail in cellular senescence. This study also reveals lactate may be a potent tumor-promoting factor and provides the basis for the development of lactate-targeted therapy.

Krüpple like lactor 12 expression in colorectal cancer tissues and its relationship with epithelial mesenchymal transition

Objective To explore the mechanism of krupple like lactor 12 (KLF12) in epithelial mesenchymal transition (EMT) of colorectal cancer. Methods Immunohistochemistry technique was utilized to detect the expression of KLF12, E-cadherin, N-cadherin, Vimentin and Snail in cancer tissues and adjacent mucosa tissues of 85 colorectal cancer patients, and clinical and follow-up data were also collected. KLF12-small interfering RNA (siRNA) was synthesized and transfected into HT-29 cells. Methyl thiazol tetrazolium (MTT) assay was applied to detect cell viability. Wound assay and Transwell assay were used to test invasion and migration of cells. The mRNA and protein expression of related genes was detected by real time reverse transcriptase-polymerase chain reaction (RT-PCR) and Western blotting, respectively. Results Results of immunohistochemistry demonstrated that the positive rate of KLF12, N-cadherin, Vimentin and Snail proteins in cancer tissues was higher, and that of E-cadherin was lower than that in adjacent mucosa tissues (χ2=43.724, 26.145, 35.788, 10.985, 59.225 respectively, P=0.000). The expression of KLF12 was associated with depth of tumors (χ2=7.773, P=0.005), and patients positive for KLF12 had poor prognosis (χ2=8.724, P=0.003). Strongest KLF12 protein was found in HT-29 cells (P=0.000). Cell viability, invasion and migration decreased after KLF12 was inhibited (F=22.541, 15.002 and 21.908 respectively, P=0.000). The expression of N-cadherin and Snail decreased, and E-cadherin increased after KLF12 was inhibited (P=0.000). Conclusion KLF12 might be involved in EMT of colorectal cancer to enhance invasion and metastasis. Key words: Kruppel-like transcription factor 12; Colorectal cancer; Epithelial mesenchymal transition; Invasion; Metastasis; Prognosis

Effects of monobutyl phthalate on migration and invasion of mouse Leydig tumor cells

Objective: This study aimed to investigate the influence of monobutyl phthalate (MBP) on the expressions of epithelial-mesenchymal transition (EMT)-related proteins, migration and invasion of mouse Leydig tumor cells (MLTC-1) cells. Methods: After exposed to different doses of MBP (0、10(-7)、10(-6), 10(-5), 10(-4), 10(-3) mol/L) for 24 h or 48 h, cell viability was determined by 3-(4 5-dimethyl-2-thiazolyl)-2 5-diphenyl-2-H-tetrazolium bromide (MTT) assay. Expressions of vimentin, E-cadherin, N-cadherin and Snail proteins related to EMT were detected by Western blot. The ability of migration and invasion of MLTC-1 were assessed by wound healing assay and Transwell Boyden chamber assay, respectively. Results: Relative expressions of vimentin, Snail and N-cadherin proteins were promoted ((1.56±0.07) vs (1.78±0.08), (1.22±0.06) vs (1.44±0.07), (1.33±0.11) vs (2.19±0.06), all P values were<0.001) and E-cadherin (0.66±0.09) vs (0.47±0.06), P<0.001,protein was inhibited after the cells stimulated with MBP (0, 10(-7) and 10(-6) mol/L). The capability of wound closure of MLTC-1 cells were (6.64±2.07)%, (15.61±2.83)%, (39.91±0.33)%, respectively and the invading/migrating cells were (32.67±3.51), (57.67±2.52), (82.67±6.51), respectively, which were obviously increased under MBP treatments (0, 10(-7) and 10(-6) mol/L) (all P values were <0.001). Conclusion: Monobutyl phthalate affected the expressions of EMT-related proteins and enhanced the migration and invasion of MLTC-1 cells.