Nuclear expression of snail is an independent negative prognostic factor in human breast cancer

Interactions and Feedbacks in E-Cadherin Transcriptional Regulation

Epithelial tissues rely on the adhesion between participating cells to retain their integrity. The transmembrane protein E-cadherin is the major protein that mediates homophilic adhesion between neighbouring cells and is, therefore, one of the critical components for epithelial integrity. E-cadherin downregulation has been described extensively as a prerequisite for epithelial-to-mesenchymal transition and is a hallmark in many types of cancer. Due to this clinical importance, research has been mostly focused on understanding the mechanisms leading to transcriptional repression of this adhesion molecule. However, in recent years it has become apparent that re-expression of E-cadherin is a major step in the progression of many cancers during metastasis. Here, we review the currently known molecular mechanisms of E-cadherin transcriptional activation and inhibition and highlight complex interactions between individual mechanisms. We then propose an additional mechanism, whereby the competition between adhesion complexes and heterochromatin protein-1 for binding to STAT92E fine-tunes the levels of E-cadherin expression in Drosophila but also regulates other genes promoting epithelial robustness. We base our hypothesis on both existing literature and our experimental evidence and suggest that such feedback between the cell surface and the nucleus presents a powerful paradigm for epithelial resilience.

MicroRNA-205-5p targets the HOXD9-Snail1 axis to inhibit triple negative breast cancer cell proliferation and chemoresistance

MicroRNA-205 (miR-205) is believed to be related to the progress of tumors. HOXD9 has been proved to be expressed abnormally in several kinds of cancers. However, the role of miR-205 and HOXD9 in breast cancer remains unclear. The biological role of miR-205 in breast cancer cell proliferation and chemoresistance was investigated. The expression of miR-205 in clinical tissues and breast cancer cell lines were analyzed using quantitative real-time PCR test (qRT-PCR). Overexpression and knockdown models of miR-205 were established to study cell proliferation and chemotherapy-resistant. Moreover, the potential relationships between miR-205 and HOXD9/Snail1 were measured using qRT-PCR, western blot, and chemotherapy-resistant study. miR-205 was lowly expressed in breast cancer tissues and cell lines. Overexpression of miR-205 could inhibit cell proliferation and chemotherapy-resistance. Moreover, we proved that miR-205 could target the HOXD9-Snail1 axis to suppress triple negative breast cancer cell proliferation and chemoresistance. The activation of Snail1 gene by HOXD9 was also proved in this study. The present study may provide a novel insight for the therapeutic strategies of breast cancer through targeting miR-205/HOXD9/Snail1.

Interplay between p53 and non-coding RNAs in the regulation of EMT in breast cancer

The epithelial-mesenchymal transition (EMT) plays a pivotal role in the differentiation of vertebrates and is critically important in tumorigenesis. Using this evolutionarily conserved mechanism, cancer cells become drug-resistant and acquire the ability to escape the cytotoxic effect of anti-cancer drugs. In addition, these cells gain invasive features and increased mobility thereby promoting metastases. In this respect, the process of EMT is critical for dissemination of solid tumors including breast cancer. It has been shown that miRNAs are instrumental for the regulation of EMT, where they play both positive and negative roles often as a part of a feed-back loop. Recent studies have highlighted a novel association of p53 and EMT where the mutation status of p53 is critically important for the outcome of this process. Interestingly, p53 has been shown to mediate its effects via the miRNA-dependent mechanism that targets master-regulators of EMT, such as Zeb1/2, Snail, Slug, and Twist1. This regulation often involves interactions of miRNAs with lncRNAs. In this review, we present a detailed overview of miRNA/lncRNA-dependent mechanisms that control interplay between p53 and master-regulators of EMT and their importance for breast cancer.

AXIN2 and SNAIL expression predict the risk of recurrence in cutaneous squamous cell carcinoma after Mohs micrographic surgery

Recurrence is a common complication observed during cutaneous squamous cell carcinoma (cSCC) treatment; however, biomarkers for predicting recurrence in cSCC remain unknown. The present study aimed to investigate the predictive value of axis inhibition protein 2 (AXIN2) and SNAIL expression in cSCC recurrence. AXIN2 and SNAIL expression was evaluated using immunohistochemistry in 111 cSCC tissue samples obtained from 18 patients who presented recurrence (recurrence interval, 1–91 months) and 93 patients who did not experience recurrence following Mohs micrographic surgery (MMS) during the follow-up period (156 months). Nomogram construction was performed using patients' clinicopathological characteristics and AXIN2 and SNAIL protein expression. The results demonstrated that high AXIN2 (histoscore >100) and SNAIL (histoscore >100) expression was detected in 35 and 44 cSCC tissues, respectively. Furthermore, the expression levels of AXIN2 and SNAIL were significantly associated in patients with cSCC (P=0.001). AXIN2 and SNAIL expression levels were significantly associated with tumor size (P=0.021 and P=0.044, respectively) and recurrence of cSCC (P=0.017 and P=0.042, respectively). In addition, the results of the Kaplan-Meier curve analysis revealed that recurrence-free survival was significantly associated with tumor size (P=0.025), differentiation status (P<0.001), AXIN2 expression (P=0.001) and SNAIL expression (P=0.001). Furthermore, the results of the multivariate analysis demonstrated that age (P=0.043), AXIN2 expression (P=0.001) and SNAIL expression (P=0.045) were independent risk factors for cSCC recurrence in the present cohort. A nomogram for predicting the 1-, 2-, 3-, and 5-year recurrence-free survival was developed for patients with cSCC by including independent risk factors with a concordance index of 0.75. The results suggested that high AXIN2 and SNAIL expression may be considered as potential risk factors for cSCC recurrence. This nomogram may therefore be useful to assess the probability of recurrence in patients with cSCC following MMS.

Long noncoding RNA LINC00511 promotes cell growth and invasion in triple-negative breast cancer by interacting with Snail

Purpose: Aberrant long noncoding RNA expression has been frequently reported in cancer research, including in triple-negative breast cancer (TNBC). The aim of the present study was to investigate the involvement of LINC00511 in the progression and prognosis of TNBC.

Materials and methods: The expression level of LINC00511 was examined by RT-PCR in TNBC tissues and in cell lines. MTT and colony formation assays were used to examine the cell growth ability. A Boyden assay was used to examine the cell invasion ability. RNA pull-down and RNA immunoprecipitation (RIP) assays were used to examine the proteins that interacted with LINC00511.

Results: We demonstrated that the LINC00511 expression level was elevated in TNBC tissues when compared with that in normal breast tissues. The downregulation of LINC00511 decreased TNBC cell growth and invasion compared to those of the controls. To explore the molecular mechanisms underlying the biological activity of LINC00511, we identified proteins that bound to LINC00511 with RNA pull-down experiments. We showed that LINC00511 binds to the β-transducin repeat containing (BTRC) E3 ubiquitin protein. Mechanistically, LINC00511 maintained the stability of Snail by impeding its ubiquitination and degradation by the BTRC E3 ubiquitin protein.

Conclusion: Our data suggested that LINC00511 might serve as a novel molecular target for the treatment of TNBC.

Biological Aggressiveness of Subclinical No-Mass Ductal Carcinoma In Situ (DCIS) Can Be Reflected by the Expression Profiles of Epithelial-Mesenchymal Transition Triggers

Epithelial-mesenchymal transitions (EMTs) have been recently implicated in the process of cancer progression. The aim of this study was to assess how the preoperative expression patterns of EMT biomarkers correlate with the risk of postoperative invasion in ductal carcinoma in situ (DCIS) found on stereotactic breast biopsies. N-cadherin, Snail1, and secreted protein acidic and rich in cysteine (SPARC) immunoreactivity was observed in 8%, 62%, and 38% of tumors, respectively. Snail1 and SPARC expressions were significantly related to N-cadherin expression and to each other. The postoperative upgrading rate was associated with a positive preoperative expression of all biomarkers. Significance of Snail1 and SPARC persisted in multivariate analysis, but the impact of SPARC on invasion was more significant. When these two EMT triggers were considered together, the risk of invasion did not significantly differ between the subtypes of DCIS with single positive expression (SPARC−/Snail1+ vs. SPARC+/Snail1−). However, it was significantly lower in single-positive DCIS when compared to lesions of a double-positive profile (SPARC+/Snail1+). Moreover, there were no cases in the double-negative DCIS (SPARC−/Snail1−), with foci of infiltrating cancer found postoperatively in residual postbiopsy lesions. In contrast, DCIS with a combined high SPARC and Snail1 expression (intermediate or strong) had an invasive component in 66–100% of tumors.

High snail expression predicts a poor prognosis in breast invasive ductal carcinoma patients with HER2/EGFR-positive subtypes

BACKGROUND

High Snail expression is known as a poor prognostic factor in breast cancer. However, its prognostic impact for breast cancer with different molecular subtypes is still controversial.

METHODS

Snail expression was examined by immunohistochemistry in tissue microarray slides of 85 corresponding tumor-adjacent normal (CTAN) and 247 breast invasive ductal carcinoma (IDC) tissues. Multivariable Cox regression analysis was used to assess the impact of Snail expression on survival rate by different molecular subtypes of breast IDC patients.

RESULTS

The level of Snail expression in IDC tumor tissues was significantly higher than that in CTAN tissues. Moreover, high Snail expression had direct impacts on poor disease specific survival (DSS) and disease-free survival (DFS) in breast IDC patients with human epidermal growth factor receptor 2 (HER2)-positive and human epidermal growth factor receptor (EGFR)-positive statuses as well as the HER2 intrinsic subtype. Additionally, breast IDC patients with a combination of three prognostic factors, including high Snail expression and HER2-positive and EGFR-positive statuses, had much poor DSS and DFS with a statistically significant linear trend.

CONCLUSION

High Snail expression could predict a poor prognosis for breast IDC patients with HER2/EGFR-positive subtypes.

DNA methylation mediated silencing of microRNA-874 is a promising diagnosis and prognostic marker in breast cancer

MicroRNA-874 (miR-874) is downregulated in several human cancers and has been suggested to be a tumor suppressor gene. However, the molecular mechanism of miR-874 downregulation in breast cancer has not been well elucidated. Here we aimed to study the aberrant hyper-methylation of CpG sites with the utility of miR-874 downreregulation in breast cancer and evaluate the clinical function of miR-874 as a prognostic marker. The miR-874 expressions in cells and tissues of two breast cancer lines were measured by real-time PCR. The DNA methylation status of the miR-874 promoter region in 19 pairs of breast cancer and adjacent normal samples was analyzed with Sequenom EpiTYPER MassArray. To evaluate whether miR-874 is a potential prognostic marker in breast cancer, we also explored the clinical long-time follow-up records from The Cancer Genome Atlas (TCGA). We found miR-874 expression was downregulated in 47 pairs of breast cancer tissues. Moreover, univariate and multivariate analysis revealed miR-874 expression may be a prognostic biomarker of overall survival in breast cancer patients. Preconditioning with 5-Aza-CdR in two cell lines elevated miR-874 expressions. The data from Sequenom EpiTYPER MassArray showed that DNA methylation of the promoter region of miR-874 was upregulated and accompanied by decreased miR-874 expression, which was further confirmed by TCGA. After comprehensive considerations, we think miR-874, which might be served as a prognostic biomarker, is mediated by DNA methylation.

MicroRNA-664 Targets Insulin Receptor Substrate 1 to Suppress Cell Proliferation and Invasion in Breast Cancer

A large number of microRNAs (miRNAs) have been previously demonstrated to be dysregulated in breast cancer (BC), and alterations in miRNA expression may affect the initiation and progression of BC. This study showed that miR-664 expression was obviously reduced in BC tissues and cell lines. Resumption of the expression of miR-664 attenuated the proliferation and invasion of BC cells. The molecular mechanisms underlying the inhibitory effects of BC cell proliferation and invasion by miR-664 were also studied. Insulin receptor substrate 1 (IRS1) was identified as a novel and direct target of miR-664. In addition, siRNA-mediated silencing of IRS1 expression mimicked the suppressive effects of miR-664 overexpression in BC cells. Rescue experiments demonstrated that recovered IRS1 expression partially antagonized the inhibition of proliferation and invasion of BC cells caused by miR-664 overexpression. Thus, miR-664 may serve as a tumor suppressor in BC by directly targeting IRS1. Moreover, miR-664 downregulation in BC may contribute to the occurrence and development of BC, suggesting that miR-664 may be a novel therapeutic target for patients with BC.

Targeting of GIT1 by miR-149* in breast cancer suppresses cell proliferation and metastasis in vitro and tumor growth in vivo

Breast cancer remains a major cause of cancer-related death in women worldwide. Dysregulation of microRNAs (miRNAs) is involved in the initiation and progression of breast cancer. Moreover, it was found that GIT1 was widely involved in the development of many human cancers. Herein, we aimed to investigate the expression changes of miR-149* and GIT1 and the functional effects of miR-149*/GIT1 link in breast cancer. Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) and Western blot (WB) were used to examine the expression levels of miR-149* and GIT1. Dual luciferase reporter assay was utilized to confirm the target interaction between miR-149* and GIT1. The biological functions, including cell proliferation, invasion, and migration, of miR-149* and GIT1 were determined by MTT assay and Transwell assays, respectively. Eventually, the tumor xenograft model in nude mice injected with stable transfected MDA-MB-231 cells was established to verify the effects of miR-149* and GIT1 on tumor growth. Our results showed that miR-149* expression was decreased, whereas GIT1 expression was increased in clinical samples of breast cancer. Based on the inverse expression trend between miR-149* and GIT1, we further demonstrated that miR-149* indeed directly targets GIT1. Subsequently, it was observed that inhibition of miR-149* significantly promoted cell proliferation, invasion, and migration, but the ability of cell proliferation, invasion, and migration was obviously declined after silencing of GIT1 in MDA-MB-231 cells transfected with miR-149* mimic and/or si-GIT1. Finally, it was also found that elevated miR-149* decelerated the tumor growth, while restored GIT1 accelerated the tumor growth in nude mice after 35 days of tumor xenograft. Collectively, these findings concluded that miR-149* might exert a tumor suppressive role in breast cancer by targeting GIT1.

Combined detection of Twist1, Snail1 and squamous cell carcinoma antigen for the prognostic evaluation of invasion and metastasis in cervical squamous cell carcinoma

BACKGROUND

Cervical cancer is one of the most common malignant tumours of the female reproductive system, ranking second only to breast cancer in morbidity worldwide. Essential features of the progression of cervical cancer are invasion and metastasis, which are closely related to disease prognosis and mortality rate. At the present time there is no effective method to evaluate cancer invasion and metastasis before surgery. Here we report our study on molecular changes in biopsy tissue for the prognostic evaluation of cancer invasion and metastasis.

PATIENTS AND METHODS

Expression of the epithelial-mesenchymal transition-inducing transcription factors Twist1 and Snail1 was detected by immunohistochemistry in 32 normal, 36 low-grade squamous intraepithelial neoplasia (LSIL), 54 high-grade squamous intraepithelial neoplasia (HSIL) and 320 cervical squamous cell carcinoma (CSCC) samples. The correlation between the expression of Twist1, Snail1 and squamous cell carcinoma antigen (SCCA) in CSCC tissues and clinical pathology results was evaluated. A transwell migration and invasion assay was used to explore the roles of Twist1 and Snail1 in the invasion of cancer cells. Lymph node metastasis and lymphovascular space invasion (LVSI) rates for the following groups were analysed: SCCA(+) group, Twist1(+) group, Snail1(+) group, Twist1(+)Snail1(+)group, Twist1(+)SCCA(+)group, Snail1(+)SCCA(+)group and Twist1(+)Snail1(+)SCCA(+) group.

RESULTS

The expression of Twist1 and Snail1 was significantly upregulated in HSIL and CSCC (p < 0.05). Twist1 and Snail1 expression levels were associated with LVSI, lymph node metastasis and histological grade (p < 0.05) but not with age or FIGO stage (p > 0.05). The expression of SCCA was associated with LVSI, lymph node metastasis, FIGO stage and histological grade (p < 0.05) but not with age (p > 0.05). Twist1 was an independent factor contributing to the invasion ability of cervical cancer cells. In addition, the positive rate of lymph node metastasis and LVSI was higher in the Twist1(+)Snail1(+)SCCA(+) group than in the SCCA(+) group, Twist1(+) group and Snail1(+) group, respectively (p < 0.05).

CONCLUSION

Combined detection of Twist1 and Snail1 in SCCA-positive biopsy specimens may be a potential method for evaluating the invasion and metastasis of CSCC prior to surgery.

Epithelial-mesenchymal transition inducer Snail1 and invasive potential of intraductal breast cancer

BACKGROUND AND OBJECTIVES

Transcription factor Snail1 is a key inducer of epithelial-mesenchymal transition (EMT), a biological process implicated in the cancer progression and metastasis. The aim of the study was to investigate Snail1 expression in DCIS found on breast biopsy and assess its predictive value for the final invasion.

METHODS

A total of 209 patients with histologically diagnosed pure DCIS entered the study. Snail1 reactivity was evaluated with immunohistochemistry in tumor tissue from stereotactic vacuum-assisted biopsy of suspicious microcalcifications.

RESULTS

Snail1 staining was observed in 62% of tumors: weak, intermediate, and strong in 27%, 21%, and 14% of lesions, respectively. Positive Snail1 expression was significantly rarer in DCIS presenting as powdery microcalcifications, when compared with crushed stone-like and casting-type and was more common in DCIS with comedonecrosis. Correlation with other features was not significant. None of standard parameters significantly influenced the upgrading rate. In contrast, in uni- and multivariate analysis the risk of postoperative invasion was significantly associated with positive Snail1 immunoreactivity. Moreover, there was a significant stepwise increase of upgrading rate according to Snail1 expression in DCIS cells: weak 9%, intermediate 26%, and strong 55%, respectively.

CONCLUSIONS

Snail1 can reflect the invasive potential of DCIS and help identify its more aggressive subtypes.

MicroRNA-215 acts as a tumor suppressor in breast cancer by targeting AKT serine/threonine kinase 1

There are accumulating reports that microRNAs are dysregulated in a number of human cancer types, and that they may function as tumor suppressors or oncogenes in tumorigenesis and tumor development. microRNA-215 (miR-215) has been identified as a tumor suppressor in epithelial ovarian, pancreatic, non-small cell lung and colon cancer, whereas it may act as an oncogene in gastric and cervical cancer. The role of miR-215 in breast cancer carcinogenesis and progression has yet to be elucidated. In the present study, the expression level of miR-215 was determined in breast cancer tissues and cell lines using the reverse transcription-quantitative polymerase chain reaction. The effects of miR-215 overexpression on proliferation and the invasive capacity of breast cancer cells were assessed using MTT and cell invasion assays. The results revealed that miR-215 was significantly downregulated in breast cancer tissues and cell lines. Restoration of miR-215 expression inhibited the proliferation and invasion of breast cancer cells. The underlying molecular mechanism for the suppression of proliferation and invasion by miR-215 was investigated. AKT serine/threonine kinase 1 (AKT1) was validated as a novel direct target of miR-215, and the effect of AKT1 small interfering RNA mimicked the effect of miR-215 overexpression in breast cancer cells. These results indicated that miR-215 acted as a tumor suppressor, and that its downregulation in tumor tissues may contribute to the carcinogenesis and progression of breast cancer, indicating that miR-215 may be a novel therapeutic target for the treatment of breast cancer.

The GRHL2/ZEB Feedback Loop-A Key Axis in the Regulation of EMT in Breast Cancer

More than 90% of cancer-related deaths are caused by metastasis. Epithelial-to-Mesenchymal Transition (EMT) causes tumor cell dissemination while the reverse process, Mesenchymal-to-Epithelial Transition (MET) allows cancer cells to grow and establish a potentially deadly metastatic lesion. Recent evidence indicates that in addition to E and M, cells can adopt a stable hybrid Epithelial/Mesenchymal (E/M) state where they can move collectively leading to clusters of Circulating Tumor Cells-the "bad actors" of metastasis. EMT is postulated to occur in all four major histological breast cancer subtypes. Here, we identify a set of genes strongly correlated with CDH1 in 877 cancer cell lines, and differentially expressed genes in cell lines overexpressing ZEB1, SNAIL, and TWIST. GRHL2 and ESRP1 appear in both these sets and also correlate with CDH1 at the protein level in 40 breast cancer specimens. Next, we find that GRHL2 and CD24 expression coincide with an epithelial character in human mammary epithelial cells. Further, we show that high GRHL2 expression is highly correlated with worse relapse-free survival in all four subtypes of breast cancer. Finally, we integrate CD24, GRHL2, and ESRP1 into a mathematical model of EMT regulation to validate the role of these players in EMT. Our data analysis and modeling results highlight the relationships among multiple crucial EMT/MET drivers including ZEB1, GRHL2, CD24, and ESRP1, particularly in basal-like breast cancers, which are most similar to triple-negative breast cancer (TNBC) and are considered the most dangerous subtype. J. Cell. Biochem. 118: 2559-2570, 2017. © 2017 Wiley Periodicals, Inc.

Snail1-dependent p53 repression regulates expansion and activity of tumour-initiating cells in breast cancer

The zinc-finger transcription factor Snail1 is inappropriately expressed in breast cancer and associated with poor prognosis. While interrogating human databases, we uncovered marked decreases in relapse-free survival of breast cancer patients expressing high Snail1 levels in tandem with wild-type, but not mutant, p53. Using a Snail1 conditional knockout model of mouse breast cancer that maintains wild-type p53, we find that Snail1 plays an essential role in tumour progression by controlling the expansion and activity of tumour-initiating cells in preneoplastic glands and established tumours, whereas it is not required for normal mammary development. Growth and survival of preneoplastic as well as neoplastic mammary epithelial cells is dependent on the formation of a Snail1/HDAC1/p53 tri-molecular complex that deacetylates active p53, thereby promoting its proteasomal degradation. Our findings identify Snail1 as a molecular bypass that suppresses the anti-proliferative and pro-apoptotic effects exerted by wild-type p53 in breast cancer.

Targeting the SIN3A-PF1 interaction inhibits epithelial to mesenchymal transition and maintenance of a stem cell phenotype in triple negative breast cancer

Triple negative breast cancer (TNBC) is characterized by a poorly differentiated phenotype and limited treatment options. Aberrant epigenetics in this subtype represent a potential therapeutic opportunity, but a better understanding of the mechanisms contributing to the TNBC pathogenesis is required. The SIN3 molecular scaffold performs a critical role in multiple cellular processes, including epigenetic regulation, and has been identified as a potential therapeutic target. Using a competitive peptide corresponding to the SIN3 interaction domain of MAD (Tat-SID), we investigated the functional consequences of selectively blocking the paired amphipathic α-helix (PAH2) domain of SIN3. Here, we report the identification of the SID-containing adaptor PF1 as a factor required for maintenance of the TNBC stem cell phenotype and epithelial-to-mesenchymal transition (EMT). Tat-SID peptide blocked the interaction between SIN3A and PF1, leading to epigenetic modulation and transcriptional downregulation of TNBC stem cell and EMT markers. Importantly, Tat-SID treatment also led to a reduction in primary tumor growth and disseminated metastatic disease in vivo. In support of these findings, knockdown of PF1 expression phenocopied treatment with Tat-SID both in vitro and in vivo. These results demonstrate a critical role for a complex containing SIN3A and PF1 in TNBC and provide a rational for its therapeutic targeting.

MicroRNA-106b targets FUT6 to promote cell migration, invasion, and proliferation in human breast cancer

It is demonstrated that the maladjustment of microRNA (miRNA) plays significant roles in the occurrence and development of tumors. MicroRNA-106b-5p (miR-106b), a carcinogenic miRNA, is identified as a dysregulated miRNA in human breast cancer. In this article, the expression levels of miR-106b were discovered to be particularly higher in breast cancer tissues than that in the corresponding adjacent tissues. Accordingly, miR-106b was higher expressed in the breast cancer cell lines compared with that in the normal breast cell lines. Moreover, according to the data previously reported, increased expression of miR-106b was significantly associated with advanced clinical stages and poor prognosis in breast cancer. Fucosyltransferase 6 (FUT6), a member of the fucosyltransferase (FUT) family, was found to have a reduced expression in tissues or cells with higher level of miR-106b in breast cancer. Additionally, down-regulation of miR-106b increased the expression of FUT6 and resulted in an obvious decrease of cell migration, invasion, and proliferation in MDA-MB-231 cells. Furthermore, over-expressed FUT6 reversed the impacts of up-regulated miR-106b on cell migration, invasion, and proliferation in MCF-7 cells, indicating that FUT6 might be directly targeted by miR-106b and serve as therapeutic targets for breast cancer. In brief, our results strongly showed that the low expression of FUT6 regulated by miR-106b contributed to cell migration, invasion, and proliferation in human breast cancer. © 2016 IUBMB Life, 68(9):764-775, 2016.

The clinical significance of snail protein expression in gastric cancer: a meta-analysis

BACKGROUND

Snail is a typical transcription factor that could induce epithelial-mesenchymal transition (EMT) and cancer progression. There are some related reports about the clinical significance of snail protein expression in gastric cancer. However, the published results were not completely consistent. This study was aimed to investigate snail expression and clinical significance in gastric cancer.

RESULTS

A systematic review of PubMed, CNKI, Weipu, and Wanfang database before March 2015 was conducted. We established an inclusion criterion according to subjects, method of detection, and results evaluation of snail protein. Meta-analysis was conducted using RevMan4.2 software. And merged odds ratio (OR) and 95 % CI (95 % confidence interval) were calculated. Also, forest plots and funnel plot were used to assess the potential of publication bias. A total of 10 studies were recruited. The meta-analysis was conducted to evaluate the positive rate of snail protein expression. OR and 95 % CI for different groups were listed below: (1) gastric cancer and para-carcinoma tissue [OR = 6.15, 95 % CI (4.70, 8.05)]; (2) gastric cancer and normal gastric tissue [OR = 17.00, 95 % CI (10.08, 28.67)]; (3) non-lymph node metastasis and lymph node metastasis [OR = 0.40, 95 % CI (0.18, 0.93)]; (4) poor differentiated cancer, highly differentiated cancer, and moderate cancer [OR = 3.34, 95 % CI (2.22, 5.03)]; (5) clinical stage TI + TII and stage TIII + TIV [OR = 0.38, 95 % CI (0.23, 0.60)]; (6) superficial muscularis and deep muscularis [OR = 0.18, 95 % CI (0.11, 0.31)].

CONCLUSIONS

Our results indicated that the increase of snail protein expression may play an important role in the carcinogenesis, progression, and metastasis of gastric cancer. And this result might provide instruction for the diagnosis, therapy, and prognosis of gastric cancer.

Prognostic Value of EMT-inducing Transcription Factors (EMT-TFs) in Metastatic Breast Cancer: A Systematic Review and Meta-analysis

The epithelial-to-mesenchymal transition (EMT) is a vital control point in metastatic breast cancer (MBC). TWIST1, SNAIL1, SLUG, and ZEB1, as key EMT-inducing transcription factors (EMT-TFs), are involved in MBC through different signaling cascades. This updated meta-analysis was conducted to assess the correlation between the expression of EMT-TFs and prognostic value in MBC patients. A total of 3,218 MBC patients from fourteen eligible studies were evaluated. The pooled hazard ratios (HR) for EMT-TFs suggested that high EMT-TF expression was significantly associated with poor prognosis in MBC patients (HRs = 1.72; 95% confidence intervals (CIs) = 1.53–1.93; P = 0.001). In addition, the overexpression of SLUG was the most impactful on the risk of MBC compared with TWIST1 and SNAIL1, which sponsored fixed models. Strikingly, the increased risk of MBC was less associated with ZEB1 expression. However, the EMT-TF expression levels significantly increased the risk of MBC in the Asian population (HR = 2.11, 95% CI = 1.70–2.62) without any publication bias (t = 1.70, P = 0.11). These findings suggest that the overexpression of potentially TWIST1, SNAIL1 and especially SLUG play a key role in the aggregation of MBC treatment as well as in the improvement of follow-up plans in Asian MBC patients.

Translating epithelial mesenchymal transition markers into the clinic: Novel insights from proteomics

The growing understanding of the molecular mechanisms underlying epithelial-to-mesenchymal transition (EMT) may represent a potential source of clinical markers. Despite EMT drivers have not yet emerged as candidate markers in the clinical setting, their association with established clinical markers may improve their specificity and sensitivity. Mass spectrometry-based platforms allow analyzing multiple samples for the expression of EMT candidate markers, and may help to diagnose diseases or monitor treatment efficiently. This review highlights proteomic approaches applied to elucidate the differences between epithelial and mesenchymal tumors and describes how these can be used for target discovery and validation.

MicroRNA-145 inhibits growth and migration of breast cancer cells through targeting oncoprotein ROCK1

MicroRNAs are small non-coding RNAs that may also function as oncogenes and tumor suppressor genes, as the abnormal expression of microRNAs is associated with various human tumors. MicroRNA-145 (miR-145) inhibits growth and increases chemo- or radiosensitivity in various cancers. However, the role of miR-145 in breast cancer progression remains unknown. In this study, miR-145 expression level was measured via quantitative real-time PCR in 88 pairs of human breast cancer tissues and adjacent normal tissues and in a panel of human breast cancer cell lines. Cell proliferation and cell migration were assessed by cell viability assay and transwell assay. Western blot was used to verify Rho-associated protein kinase 1 (ROCK1) as a novel target gene of miR-145. Our results showed that miR-145 was frequently downregulated in breast cancer tissues and cell lines. Overexpression of miR-145 in MCF-7 and BT-549 cell lines significantly inhibited cell proliferation, migration, and invasion in vitro. ROCK1 was identified as a target of miR-145, and ectopic expression of miR-145 downregulated ROCK1. Our findings indicate that miR-145 acts as a tumor suppressor and its downregulation in tumor tissues may contribute to the progression of breast cancer through a mechanism involving ROCK1, suggesting miR-145 as a potential new diagnostic and therapeutic target for the treatment of breast cancer.

Combinatorial TGF-β attenuation with paclitaxel inhibits the epithelial-to-mesenchymal transition and breast cancer stem-like cells

Distant relapse after chemotherapy is an important clinical issue for treating breast cancer patients and results from the development of cancer stem-like cells (CSCs) during chemotherapy. Here we report that blocking epithelial-to-mesenchymal transition (EMT) suppresses paclitaxel-induced CSCs properties by using a MDA-MB-231-xenografted mice model (in vivo), and breast cancer cell lines (in vitro). Paclitaxel, one of the cytotoxic taxane-drugs such as docetaxel, increases mesenchymal markers (Vimentin and Fibronectin) and decreases an epithelial marker (Zo-1). Blocking TGF-β signaling with the TGF-β type I receptor kinase (ALK5) inhibitor, EW-7197, suppresses paclitaxel-induced EMT and CSC properties such as mammosphere-forming efficiency (MSFE), aldehyde dehydrogenase (ALDH) activity, CD44+/CD24- ratio, and pluripotency regulators (Oct4, Nanog, Klf4, Myc, and Sox2). The combinatorial treatment of EW-7197 improves the therapeutic effect of paclitaxel by decreasing the lung metastasis and increasing the survival time in vivo. We confirmed that Snail is increased by paclitaxel-induced intracellular reactive oxygen species (ROS) and EW-7197 suppresses the paclitaxel-induced Snail and EMT by attenuating paclitaxel-induced intracellular ROS. Knock-down of SNAI1 suppresses paclitaxel-induced EMT and CSC properties. These data together suggest that blocking the Snail-induced EMT with the ALK5 inhibitor attenuates metastasis after paclitaxel-therapy and that this combinatorial approach could prove useful in treating breast cancer.

The network of pluripotency, epithelial-mesenchymal transition, and prognosis of breast cancer

Breast cancer is the leading female cancer in terms of prevalence. Progress in molecular biology has brought forward a better understanding of its pathogenesis that has led to better prognostication and treatment. Subtypes of breast cancer have been identified at the genomic level and guide therapeutic decisions based on their biology and the expected benefit from various interventions. Despite this progress, a significant percentage of patients die from their disease and further improvements are needed. The cancer stem cell theory and the epithelial-mesenchymal transition are two comparatively novel concepts that have been introduced in the area of cancer research and are actively investigated. Both processes have their physiologic roots in normal development and common mediators have begun to surface. This review discusses the associations of these networks as a prognostic framework in breast cancer.

The role of adipose-derived stem cells in breast cancer progression and metastasis

Conventional breast cancer extirpation involves resection of parts of or the whole gland, resulting in asymmetry and disfiguration. Given the unsatisfactory aesthetic outcomes, patients often desire postmastectomy reconstructive procedures. Autologous fat grafting has been proposed for reconstructive purposes for decades to restore form and anatomy after mastectomy. Fat has the inherent advantage of being autologous tissue and the most natural-appearing filler, but given its inconsistent engraftment and retention rates, it lacks reliability. Implementation of autologous fat grafts with cellular adjuncts, such as multipotent adipose-derived stem cells (ADSCs), has shown promising results. However, it is pertinent and critical to question whether these cells could promote any residual tumor cells to proliferate, differentiate, or metastasize or even induce de novo carcinogenesis. Thus far, preclinical and clinical study findings are discordant. A trend towards potential promotion of both breast cancer growth and invasion by ADSCs found in basic science studies was indeed not confirmed in clinical trials. Whether experimental findings eventually correlate with or will be predictive of clinical outcomes remains unclear. Herein, we aimed to concisely review current experimental findings on the interaction of mesenchymal stem cells and breast cancer, mainly focusing on ADSCs as a promising tool for regenerative medicine, and discuss the implications in clinical translation.

Prognostic role of Twist or Snail in various carcinomas: a systematic review and meta-analysis

BACKGROUND

Twist and Snail are considered as key transcriptional repressors of E-cadherin tightly related to epithelial-to-mesenchymal transition (EMT) and cancer progression. Numerous studies have investigated the prognostic value of Twist and Snail. However, the published results were controversial or even opposite. Our article aimed to evaluate the prognostic role of Twist and Snail in patients with cancer.

DESIGN

A comprehensive literature search of PubMed, Embase and Web of Science was conducted. Pooled hazard ratios (HRs) and their corresponding 95% confidence intervals (CIs) were assessed to quantify the prognostic role.

RESULTS

The pooled HR with 38 studies for Twist was 2·18 (95% CI: 1·77-2·68, I(2) = 69·8%, P = 0·000) and for Snail with 40 studies was 1·58 (95% CI: 1·33-1·87, I(2) = 70·0%, P = 0·000), suggesting high Twist/Snail expression predicted poor prognosis related to all clinical outcomes. For Twist, the pooled HR for overall survival (OS) was 2·07 (95% CI: 1·63-2·63, I(2) = 72·6%, P = 0·000) and for progression-free/recurrence-free/metastasis-free/disease-free/cancer-free survival (PFS/RFS/MFS/DFS/CFS) was 2·36 (95% CI: 1·76-3·17, I(2) = 65·0%, P = 0·000). For Snail, the pooled HR for OS was 1·63 (95% CI: 1·33-1·99, I(2) = 70·8%, P = 0·000) and for PFS/RFS/MFS/DFS/CFS was 1·54 (95% CI: 1·17-2·02, I(2) = 59·1%, P = 0·001). All of those results were suggesting that high Twist/Snail expression was associated with poor prognosis. Furthermore, when grouped into different types of cancers, the pooled HRs were also calculated for the subgroups. No publication bias was found except studies evaluating all clinical outcomes of Twist (P = 0·006 for Begg's test and 0·006 for Egger's test).

CONCLUSIONS

Elevated Twist or Snail expression in tumour tissue indicated poor prognosis for cancer.

Snail predicts recurrence and survival of patients with localized clear cell renal cell carcinoma after surgical resection

BACKGROUND

Snail (known as SNAI1), a zinc-finger transcription factor, is best known for the induction of epithelial-to-mesenchymal transition, which has emerged as a recognized mechanism underlying epithelial cancer progression. Herein, the aim is to determine the effect of Snail expression on recurrence and survival of patients with localized clear cell renal cell carcinoma (ccRCC) following surgery.

METHODS

We retrospectively enrolled 255 patients (188 in group A and 67 in group B) with localized ccRCC undergoing nephrectomy at a single center. Prognostic value and clinical outcomes were evaluated.

RESULTS

In both groups, cytoplasmic Snail intensity correlates positively with Fuhrman grade. High nuclear but not cytoplasmic Snail intensity indicates early recurrence and poor survival of patients with localized ccRCC. Moreover, high nuclear Snail intensity predicts unfavorable survival of patients with T2-4 stage cancer and early recurrence of all stage patients. Nuclear Snail intensity was identified as an independent adverse prognostic factor for recurrence and survival. The predictive accuracy of University of Los Angeles Integrated Staging System and the Mayo Clinic Stage, Size, Grade, and Necrosis prognostic models was improved when nuclear Snail expression was added.

CONCLUSION

Nuclear Snail expression is a potential independent adverse prognostic biomarker for recurrence and survival of patients with localized ccRCC after nephrectomy.

Snail-regulated MiR-375 inhibits migration and invasion of gastric cancer cells by targeting JAK2

MicroRNAs (miRNAs) have been reported to play a critical role in cancer invasion and metastasis. Our previous study showed that miR-375 frequently downregulated in gastric cancer suppresses cell proliferation by targeting Janus kinase 2 (JAK2). Here, we further found that the expression level of miR-375 is significantly decreased in metastatic gastric cancer tissues compared with the non-metastasis controls. Ectopic expression of miR-375 inhibits the migration and invasion of gastric cancer cells partially by targeting JAK2. Furthermore, miR-375 expression is negatively regulated by the metastasis associated transcription factor Snail, which directly binds to the putative promoter of miR-375. Moreover, overexpression of Snail can partially reverse the inhibition of gastric cancer cell migration caused by miR-375. Taken together, these data suggest that miR-375 may be negatively regulated by Snail and involved in gastric cancer cell migration and invasion potentially by targeting JAK2.