P4HA2 involved in SLUG-associated EMT predicts poor prognosis of patients with KRAS-positive colorectal cancer

This study aimed to examine the immunohistochemical expression of epithelial-mesenchymal transition biomarkers: P4HA2 and SLUG in colorectal carcinoma (CRC) specimens, then to assess their relation to clinicopathological features including KRAS mutations and patients' survival, and finally to study the correlation between them in CRC. The result of this study showed that SLUG and P4HA2 were significantly higher in association with adverse prognostic factors: presence of lympho-vascular invasion, perineural invasion, higher tumor budding, tumor stage, presence of lymph node metastasis, and presence of distant metastasis. CRC specimens with KRAS mutation were associated with significant higher SLUG and P4HA2 expression. High expression of both SLUG and P4HA2 was significantly unfavorable prognostic indicator as regards overall survival (OS) and disease-free survival (DFS). In KRAS mutated cases, high P4HA2 expression was the only significant poor prognostic indicator as regarding DFS. In conclusions, our data highlight that both SLUG and P4HA2 expression may serve as potentially important poor prognostic biomarkers in CRC and targeting these molecules may be providing a novel therapeutic strategy. In KRAS mutation group, high P4HA2 expression is the only independent prognostic factor for tumor recurrence, so it can be suggested to be a novel target for therapy.

microRNA-203 inhibits migration and invasion of canine tonsillar squamous cell carcinoma cells by targeting SLUG

Objective

Squamous cell carcinoma (SCC) occurring in the tonsils (TSCC) has a poorer prognosis than SCC occurring in other regions of the oral cavity (non-tonsillar SCC [NTSCC]) because it easily metastasizes to distant organs. This study aimed to elucidate the molecular mechanisms underlying the migration and invasion of TSCC cells in vitro.

Materials and methods

This study focused on differential microRNA (miRNA) expression using microRNA microarrays and quantitative polymerase chain reaction in canine TSCC and NTSCC tissues and cell lines. A target gene of the miRNA involved in cell migration and invasion was validated by wound healing, transwell, and luciferase assays.

Results

miR-203 expression was lower in TSCC tissues than in the normal oral mucosa and NTSCC tissues. Transfection of the miR-203 mimic resulted in the downregulation of mesenchymal marker protein expression and attenuation of cell migration and invasion in TSCC cells, but not in NTSCC cells. A dual-luciferase assay revealed that miR-203 directly targeted the mesenchymal transcription factor SLUG. SLUG overexpression enhances the migration of TSCC cells.

Conclusion

Our study indicates that the miR-203/SLUG axis may be involved in the metastatic mechanisms of TSCC.

The Role of Irisin/FNDC5 Expression and Its Serum Level in Breast Cancer

Irisin (Ir) is an adipomyokine formed from fibronectin type III domain-containing protein 5 (FNDC5), which can be found in various cancer tissues. Additionally, FNDC5/Ir is suspected of inhibiting the epithelial-mesenchymal transition (EMT) process. This relationship has been poorly studied for breast cancer (BC). The ultrastructural cellular localizations of FNDC5/Ir were examined in BC tissues and BC cell lines. Furthermore, we compared serum levels of Ir with FNDC5/Ir expression in BC tissues. The aim of this study was to examine the levels of EMT markers, such as E-cadherin, N-cadherin, SNAIL, SLUG, and TWIST, and to compare their expression levels with FNDC5/Ir in BC tissues. Tissue microarrays with 541 BC samples were used to perform immunohistochemical reactions. Serum levels of Ir were assessed in 77 BC patients. We investigated FNDC5/Ir expression and ultrastructural localization in MCF-7, MDA-MB-231, and MDA-MB-468 BC cell lines and in the normal breast cell line (Me16c), which was used as the control. FNDC5/Ir was present in BC cell cytoplasm and tumor fibroblasts. FNDC5/Ir expression levels in BC cell lines were higher compared to those in the normal breast cell line. Serum Ir levels did not correlate with FNDC5/Ir expression in BC tissues but were associated with lymph node metastasis (N) and histological grade (G). We found that FNDC5/Ir correlated moderately with E-cadherin and SNAIL. Higher Ir serum level is associated with lymph node metastasis and increased grade of malignancy. FNDC5/Ir expression is associated with E-cadherin expression level.

The Immunohistochemical Expression of Epithelial-Mesenchymal Transition Markers in Precancerous Lesions and Cervical Cancer

In the epithelial-mesenchymal transition (EMT) process, cells lose their epithelial phenotype and gain mesenchymal features. This phenomenon was observed in the metastatic phase of neoplastic diseases, e.g., cervical cancer. There are specific markers that are expressed in the EMT. The aim of this study was to determine the localization of and associations between the immunohistochemical (IHC) expression of TWIST, SNAIL, and SLUG proteins in precancerous lesions and cervical cancer. The IHC analysis disclosed higher expressions of EMT markers in precancerous lesions and cervical cancer than in the control group. Moreover, stronger expression of TWIST, SNAIL, and SLUG was observed in cervical intraepithelial neoplasia grade 3 (CIN3) vs. CIN1, CIN3 vs. CIN2, and CIN2 vs. CIN1 cases (p < 0.05). In cervical cancer, IHC reactions demonstrated differences in TWIST, SNAIL, and SLUG expression in grade 1 (G1) vs. grade 2 (G2) (p < 0.0011; p < 0.0017; p < 0.0001, respectively) and in G1 vs. grade 3 (G3) (p < 0.0029; p < 0.0005; p < 0.0001, respectively). The results of our study clearly showed that existing differences in the expression of the tested markers in precancerous vs. cancerous lesions may be utilized in the diagnosis of cervical cancer. Further studies on bigger populations, as well as in comparison with well-known markers, may improve our outcomes.

Prognostic Value of IMP3 and Its Role as an Epithelial-Mesenchymal Transition Promoter in Breast Carcinoma

Breast carcinoma is now the most common cancer in the world. In view of its high mortality, there is a need to identify new prognostic biomarkers. Both IMP3 and SLUG have been implicated in cancer metastasis. This was a retrospective study conducted on 60 breast carcinoma cases using tissue microarrays. Demographic and clinicopathological details were recorded. Immunohistochemistry for IMP3 and SLUG was performed and evaluated in terms of percentage-cell-positivity and intensity of staining. A proforma was used to store data and was analyzed using SPSS v20. IMP3 positivity was found in 87% breast carcinoma cases and was significantly associated with tumor size (p = 0.03) and TNM stage (p = 0.024). IMP3 staining intensity showed significant association with histological grade (p = 0.009), TNM stage (p = 0.036), and molecular subtype (p = 0.03). SLUG immunoexpression was seen in 90% breast carcinoma cases and was significantly associated with TNM stage (p = 0.006). SLUG staining intensity was significantly associated with age (p = 0.025) and TNM stage (p = 0.004). IMP3 and SLUG immunopositivity and their staining intensities were significantly associated (p <0.001, p <0.001). IMP3 and SLUG percentage cell positivities were also significantly correlated (p <0.001). IMP3 and SLUG are, thus, poor prognostic markers with a role in tumor invasiveness and aggressiveness via epithelial-mesenchymal transition. Hence, IMP3 and SLUG-based targeted therapies may be useful in the treatment of breast carcinoma.

A reliable mouse model of liver and lung metastasis by injecting esophageal cancer stem cells (CSCs) through tail-vein injection

BACKGROUND

Esophageal Squamous Cell Carcinoma (ESCC) is a highly aggressive tumor with increased metastatic potential. Recent evidence suggests that esophageal CSCs have a crucial role in tumor initiation, progression, and resistance to conventional anti-cancer therapies. The study aimed to develop mouse model to mimic the late steps of the metastasis process using a tail-vein injection of esophageal CSCs.

METHODS AND RESULTS

The sphere formation assay was used to enrich CSCs. For analysis of tumorigenicity, YM-1 adherent cells and enriched CSCs were injected subcutaneously into dorsal flank of nude mice. The expression of SLUG, E-cad, and CTHRC1 genes was examined by Real-Time qRT-PCR and immunohistochemistry (IHC) methods. To assess the metastatic potential of adherent YM-1 cells and their enriched CSCs, we injected the cells into the tail vein of nude mice. Our findings showed the up-regulation of SLUG and down-regulation of E-cad in the esophageal CSC-derived tumors (ECSCTs) compared to adherent cells-derived tumors. There was no statistically significant difference between CTHRC1 gene expressions in both groups of tumors. IHC staining confirmed the higher expression of SLUG protein in ECSCTs compared to adherent cell-derived tumors. Enriched CSCs were able to metastasize to the lungs and livers after three months, but, metastasis of adherent cells wasn't observed.

CONCLUSION

Our study showed esophageal CSCs injected through the tail-vein injection can migrate and metastasize to the lung and liver after three months. The developed metastatic mouse model can be a valuable and relevant model to investigate the molecular and cellular mechanisms of metastasis and develop successful targeted therapies against ESCC. The present study is one of the few studies that investigate the metastasis of esophageal cancer stem cells (ESCC type) through injection into the tail vein of nude mice.

Inhibition of NF-kB/IL-6/JAK2/STAT3 Pathway and Epithelial-Mesenchymal Transition in Breast Cancer Cells by Azilsartan

Metastatic breast cancer is an incurable form of breast cancer that exhibits high levels of epithelial-mesenchymal transition (EMT) markers. Angiotensin II has been linked to various signaling pathways involved in tumor cell growth and metastasis. The aim of this study is to investigate, for the first time, the anti-proliferative activity of azilsartan, an angiotensin II receptor blocker, against breast cancer cell lines MCF-7 and MDA-MB-231 at the molecular level. Cell viability, cell cycle, apoptosis, colony formation, and cell migration assays were performed. RT-PCR and western blotting analysis were used to explain the molecular mechanism. Azilsartan significantly decreased the cancer cells survival, induced apoptosis and cell cycle arrest, and inhibited colony formation and cell migration abilities. Furthermore, azilsartan reduced the mRNA levels of NF-kB, TWIST, SNAIL, SLUG and bcl2, and increased the mRNA level of bax. Additionally, azilsartan inhibited the expression of IL-6, JAK2, STAT3, MMP9 and bcl2 proteins, and increased the expression of bax, c-PARP and cleaved caspase 3 protein. Interestingly, it reduced the in vivo metastatic capacity of MDA-MBA-231 breast cancer cells. In conclusion, the present study revealed, for the first time, the anti-proliferative, apoptotic, anti-migration and EMT inhibition activities of azilsartan against breast cancer cells through modulating NF-kB/IL-6/JAK2/STAT3/MMP9, TWIST/SNAIL/SLUG and apoptosis signaling pathways.

Immunohistochemical expression of E-cadherin, N-cadherin and Snail/slug in ameloblastoma

CONTEXT

Ameloblastoma is the most common odontogenic tumour and its histomorphological distinction into growth patterns and variants, does not accurately convey information about its biologic aggressiveness. Expression of epithelial mesenchymal transition (EMT) markers, which have been implicated in its etiogenesis, might assist in delineating aggressiveness across variants. This may help in formulating appropriate treatment modalities for its management AIMS: To determine expression of SNAIL/SLUG and ECAD/NCAD in tumour cells in clinical and histological subtypes of ameloblastoma and to establish any association between the immunostaining profile and the biologic behaviour of histologic types of ameloblastoma.

SETTINGS/DESIGN

This is a retrospective study conducted to evaluate the immunoprofile of selected clinical subtypes and histological variants to EMT factors via immunostaining to SLUG and ECAD/NCAD antibodies. Mean aggregate scores for each antibody per variant was analyzed using ANOVA or Kruskal-Wallis test when appropriate. Agreement between AR and SR regions was correlated using Spearman's correlation co-efficient.

RESULTS

A higher staining SLUG intensity in the stellate reticulum (SR) like areas relative to the ameloblast like areas (AR) was observed, without concomitant E-cadherin repression or elimination. However, a direct relationship between SLUG and N-cadherin was observed.

CONCLUSION

Expression of SLUG in the SR like areas can be utilized to predict the biologic behavior of specific clinico-histological variants, however its mechanism via alterations in cadherin switching is equivocal.

Identifying potential regulators of JAGGED1 expression in portal mesenchymal cells

Objective

Portal mesenchymal cells induce the epithelial differentiation of the bile ducts in the developing liver via one of the Delta-Notch signaling components, JAGGED1. Although this differential induction is crucial for normal liver physiology as its genetic disorder (Alagille syndrome) causes jaundice, the molecular mechanism behind JAGGED1 expression remains unknown. Here, we searched for upstream regulatory transcription factors of JAGGED1 using an integrated bioinformatics method.

Results

According to the DoRothEA database, which integrates multiple lines of evidence on the relationship between transcription factors and their downstream target genes, three transcription factors were predicted to be upstream of JAGGED1: SLUG, SOX2, and EGR1. Among these, SLUG and EGR1 were enriched in ACTA2-expressing portal mesenchymal cells in two previously reported human fetal liver single-cell RNA-seq datasets. JAGGED1-expressing portal mesenchymal cells tended to express SLUG rather than EGR1, supporting that SLUG induced JAGGED1 expression. Together with the higher confidentiality of SLUG (DoRothEA level A) over EGR1 (DoRothEA level D), we concluded that SLUG was one of the most important candidate transcription factors upstream of JAGGED1. These results add mechanistic insights into the developmental biology of how portal mesenchymal cells support biliary development in the liver.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13104-022-06058-4.

Slug and Vimentin downregulation at the metastatic site is associated with Skip-N2 metastasis of lung adenocarcinoma

OBJECTIVE

Lung cancer displays heterogeneity both in the tumor itself and in its metastatic regions. One interesting behavior of the tumor is known as Skip N2 metastasis, which N2 lymph nodes contain tumor cells while N1 are clean. In this study, mRNA levels of epithelial mesenchymal transition (EMT) related genes in skip N2 and normal N2 involvements of non-small cell lung cancer tissues were investigated to evaluate the possible molecular background that may contribute to the pathogenesis of Skip N2 metastasis.

MATERIALS AND METHODS

Eighty-three surgically resected and paraffin embedded lymph node samples of lung cancer patients were analyzed in this study, which 40 of them were Skip N2. N2 tissues were sampled from 50% tumor containing areas and total RNA was extracted. mRNA levels for 18S, E-cadherin, Vimentin, ZEB1 and SLUG were analyzed via qPCR and E-cadherin and vimentin protein levels via immunohistochemistry (IHC). Bioinformatic analysis were adopted using online datasets to evaluate significantly co-expressed genes with SLUG in lung cancer tissue samples.

RESULTS

Skip-N2 patients who had adenocarcinoma subtype had better survival rates. Comparative analysis of PCR results indicated that Skip N2 tumor tissues had increased E-Cadherin/Vimentin ratio and ZEB1 mRNA expression, and significantly decreased levels of SLUG. E-cadherin IHC staining were higher in Skip N2 and Vimentin were in Non-Skip N2. TP63 had a strong correlation with SLUG expression in the bioinformatics analyses.

CONCLUSION

The results indicate that, at molecular level, Skip N2 pathogenesis has different molecular background and regulation of SLUG expression may orchestrate the process.

TMPRSS4 promotes cancer stem-like properties in prostate cancer cells through upregulation of SOX2 by SLUG and TWIST1

Background

Transmembrane serine protease 4 (TMPRSS4) is a cell surface–anchored serine protease. Elevated expression of TMPRSS4 correlates with poor prognosis in colorectal cancer, gastric cancer, prostate cancer, non–small cell lung cancer, and other cancers. Previously, we demonstrated that TMPRSS4 promotes invasion and proliferation of prostate cancer cells. Here, we investigated whether TMPRSS4 confers cancer stem–like properties to prostate cancer cells and characterized the underlying mechanisms.

Methods

Acquisition of cancer stem–like properties by TMPRSS4 was examined by monitoring anchorage-independent growth, tumorsphere formation, aldehyde dehydrogenase (ALDH) activation, and resistance to anoikis and drugs in vitro and in an early metastasis model in vivo. The underlying molecular mechanisms were evaluated, focusing on stemness-related factors regulated by epithelial–mesenchymal transition (EMT)-inducing transcription factors. Clinical expression and significance of TMPRSS4 and stemness-associated factors were explored by analyzing datasets from The Cancer Genome Atlas (TCGA).

Results

TMPRSS4 promoted anchorage-independent growth, ALDH activation, tumorsphere formation, and therapeutic resistance of prostate cancer cells. In addition, TMPRSS4 promoted resistance to anoikis, thereby increasing survival of circulating tumor cells and promoting early metastasis. These features were accompanied by upregulation of stemness-related factors such as SOX2, BMI1, and CD133. SLUG and TWIST1, master EMT-inducing transcription factors, made essential contributions to TMPRSS4-mediated cancer stem cell (CSC) features through upregulation of SOX2. SLUG stabilized SOX2 via preventing proteasomal degradation through its interaction with SOX2, while TWIST1 upregulated transcription of SOX2 by interacting with the proximal E-box element in the SOX2 promoter. Clinical data showed that TMPRSS4 expression correlated with the levels of SOX2, PROM1, SNAI2, and TWIST1. Expression of SOX2 was positively correlated with that of TWIST1, but not with other EMT-inducing transcription factors, in various cancer cell lines.

Conclusions

Together, these findings suggest that TMPRSS4 promotes CSC features in prostate cancer through upregulation of the SLUG- and TWIST1-induced stem cell factor SOX2 beyond EMT. Thus, TMPRSS4/SLUG–TWIST1/SOX2 axis may represent a novel mechanism involved in the control of tumor progression.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13046-021-02147-7.

Dynamic EMT: a multi-tool for tumor progression

The process of epithelial-mesenchymal transition (EMT) is fundamental for embryonic morphogenesis. Cells undergoing it lose epithelial characteristics and integrity, acquire mesenchymal features, and become motile. In cancer, this program is hijacked to confer essential changes in morphology and motility that fuel invasion. In addition, EMT is increasingly understood to orchestrate a large variety of complementary cancer features, such as tumor cell stemness, tumorigenicity, resistance to therapy and adaptation to changes in the microenvironment. In this review, we summarize recent findings related to these various classical and non-classical functions, and introduce EMT as a true tumorigenic multi-tool, involved in many aspects of cancer. We suggest that therapeutic targeting of the EMT process will-if acknowledging these complexities-be a possibility to concurrently interfere with tumor progression on many levels.

miR-149-PARP-2 Signaling Regulates E-cadherin and N-cadherin Expression in the Murine Model of Endometrium Receptivity

Cadherins play an essential role in the attachment of the blastocyst to the endometrium, a process known as endometrial receptivity. Loss of E-cadherin expression is essential during the process, while the expression level of the other cadherin, N-cadherin, has been reported to be altered in cases of infertility. Both E-cadherin and N-cadherin can be regulated by members of the PARP family. Specifically, PARP-2, which is under the epigenetic control of miR-149, has been observed to promote E-cadherin expression in other human cells. We investigated the roles of E-cadherin and N-cadherin in endometrial receptivity using mouse models for normal endometrial receptivity, pseudopregnancy, and LPS-induced endometrial receptivity failure. E-cadherin and phosphorylated E-cadherin were predominantly expressed during pre-receptive stages as well as in the implantation site of the receptive stage, which were observed reduced during the later stages of implantation in both implantation and non-implantation regions, while N-cadherin was detected only at pre-receptive stages. E-cadherin and N-cadherin were also seen in the uterus during pseudopregnancy, showing a downregulation trend during receptive and post-receptive stages. LPS-induced failed endometrial receptivity showed upregulation of E-cadherin and downregulation of N-cadherin. The E-cadherin expression promoter, GSK-3, was lost and its suppressor, SLUG was upregulated during normal course of endometrial receptivity in mouse model, while GSK-3 was increased during LPS-induced failed embryo implantation. In an in vitro model of embryo implantation, E-cadherin expression is promoted by PARP-2 and regulated by miR-149 epigenetically in human endometrium epithelial cells. In conclusion, E-cadherin is predominantly expressed during pre-receptive stage and promoted by PARP-2, which is regulated by miR-149 in the endometrial epithelial cells.

SLUG-related partial epithelial-to-mesenchymal transition is a transcriptomic prognosticator of head and neck cancer survival

Partial epithelial‐to‐mesenchymal transition (pEMT) contributes to cellular heterogeneity that is associated with nodal metastases and unfavorable clinical parameters in head and neck squamous cell carcinomas (HNSCCs). We developed a single‐cell RNA sequencing signature‐based pEMT quantification through cell type‐dependent deconvolution of bulk RNA sequencing and microarray data combined with single‐sample scoring of molecular phenotypes (Singscoring). Clinical pEMT‐Singscores served as molecular classifiers in multivariable Cox proportional hazard models and high scores prognosticated poor overall survival and reduced response to irradiation as independent parameters in large HNSCC cohorts [The Cancer Genome Atlas (TCGA), MD Anderson Cancer Centre (MDACC), Fred Hutchinson Cancer Research Center (FHCRC)]. Differentially expressed genes confirmed enhanced cell motility and reduced oxidative phosphorylation and epithelial differentiation in pEMT^high patients. In patients and cell lines, the EMT transcription factor SLUG correlated most strongly with pEMT‐Singscores and promoted pEMT, enhanced invasion, and resistance to irradiation in vitro. SLUG protein levels in HNSCC predicted disease‐free survival, and its peripheral expression at the interphase to the tumor microenvironment was significantly increased in relapsing patients. Hence, pEMT‐Singscores represent a novel risk predictor for HNSCC stratification regarding clinical outcome and therapy response that is partly controlled by SLUG.

High BTBD7 expression positive is correlated with SLUG-predicted poor prognosis in hormone receptor-negative breast cancer

BACKGROUND

Hormone receptor-negative breast cancer (HRNBC), which includes triple-negative breast cancer (TNBC) and human epidermal growth factor receptor 2 (HER-2) overexpressing breast cancer, is prone to metastasis and has a poor prognosis. BTB/POZ domain-containing protein 7 (Btbd7) is thought to regulate SLUG and the epithelial-mesenchymal transition (EMT) process. However, the role of Btbd7 in HRNBC is unclear.

METHODS

Expression of BTBD7 and SLUG in HRNBC tumor tissue and normal adjacent tissue (NAT) as well as breast cancer cells were characterized by immunohistochemistry and immunofluorescence. MDA-MA-231 cells was transfected with BTBD7 siRNA and detected by qRT-PCR and western blot. Expression levels of Slug and EMT related proteins were detected western blot analysis. cell invasion assays were used to analyse cell invasion ability of MDA-MA-231. GO and KEGG analyses was used to analysis the gene function.

RESULTS

The total positive rate of BTBD7 expression in HRNBC tumor tissue was 66.7%, which was higher than that in NAT (52.1%) and benign breast lesion tissues (20%). Co-expression of SLUG and BTBD7 proteins could be found in HRNBC tissue and MDA-MA-231 cells. BTBD7 silencing significantly up-regulated the epithelial marker E-cadherin, down-regulated the mesenchymal markers α-SMA and SLUG and suppressed the invasion abilities of MDA-MA-231 cells. GO and KEGG analyses based on 322 DEGs showed that BTBD7 may be associated with generic transcription in breast cancer.

CONCLUSIONS

The study data indicated that BTBD7 was inversely associated with SLUG expression. Higher BTBD7 was associated with poor clinicopathologic features and prognosis in HRNBC patients. BTBD7 silencing inhibited EMT through regulation of SLUG expression. BTBD7 might act as a potential molecular target for gene therapy in HRNBC patients.

DEPTOR inhibits lung tumorigenesis by inactivating the EGFR-mTOR signals

DEPTOR plays vital roles in the regulation of cell proliferation and survival by directly modulating the activity of mTORC1/2. However, the physiological role of DEPTOR in lung tumorigenesis, as well as its clinical significance, remains elusive. In this study, we revealed that decreased DEPTOR expression correlated with increased tumor size, poor differentiation, and worse survival in patients with lung cancer. DEPTOR depletion promoted cell proliferation, survival, migration, and invasion in human lung cancer cells. Mechanistically, DEPTOR bound to the kinase domain of EGFR via its PDZ domain to inactivate EGFR signal. Thus, DEPTOR depletion not only directly activated mTORC1/2, but also relieved the inhibition of EGFR to subsequently activate mTOR signals, leading to the induction of cell proliferation and survival. Additionally, activated EGFR-mTOR signals upregulated the expression of ZEB1 and SLUG to induce epithelial-mesenchymal transition, resulting in enhanced migration and invasion. Importantly, Deptor deletion accelerated Kras^G12D;p53^fl/fl-induced lung tumorigenesis and shortened mouse life span via the activation of EGFR-mTOR signals. Collectively, our study demonstrated that DEPTOR acts as a tumor suppressor in lung tumorigenesis, and its reduction may advance the progression of human lung cancer.

Ruyiping formula inhibits metastasis via the microRNA-134-SLUG axis in breast cancer

BACKGROUND

Metastasis is the leading cause of death among breast cancer patients. MicroRNA-134 has been reported to have a tumor-suppressive role in breast cancer. Ruyiping (RYP), a traditional Chinese formula, has been shown with the ability to reduce breast cancer metastasis in pre-clinical studies. This present study was designed to examine whether miR-134 was involved in RYP-inhibited breast cancer metastasis.

METHODS

The expression of SLUG, E-Cadherin, N-Cadherin and miR-134 in MDA-MB-231 and 4 T1 cells treated with RYP or vehicle control were determined by quantitative realtime-PCR and western blot. Invasiveness determined by transwell assay as well as SLUG gene expression determined by qPCR were detected in cells transfected with chemically synthesized miR-134 mimics or inhibitors. BALB/c mice were injected with 4 T1 cells orthotopically and fed with RYP through gavage. Breast tumor growth, metastasis and tumor expression of EMT markers were detected.

RESULTS

Compared with the control, Ruyiping formula significantly inhibited SLUG-regulated breast cancer cells invasion. MiR-134 was induced by RYP in vitro and in vivo and was able to suppress SLUG by targeting its 3'UTR. RYP suppressed SLUG expression and cell invasion through miR-134. In 4 T1 tumor-bearing mice, RYP significantly inhibited 4 T1 tumor growth and lung metastasis, increased the levels of miR-134 and epithelial marker while decreased the levels of SLUG and mesenchymal marker.

CONCLUSION

Our data uncovered that Ruyiping formula exerts an anti-metastatic activity against breast cancer cells by regulating SLUG through miR-134. MiR-134-SLUG axis might be a promising strategy in breast cancer therapy.

TGF-β activates pericytes via induction of the epithelial-to-mesenchymal transition protein SLUG in glioblastoma

AIMS

In primary central nervous system tumours, epithelial-to-mesenchymal transition (EMT) gene expression is associated with increased malignancy. However, it has also been shown that EMT factors in gliomas are almost exclusively expressed by glioma vessel-associated pericytes (GA-Peris). In this study, we aimed to identify the mechanism of EMT in GA-Peris and its impact on angiogenic processes.

METHODS

In glioma patients, vascular density and the expression of the pericytic markers platelet derived growth factor receptor (PDGFR)-β and smooth muscle actin (αSMA) were examined in relation to the expression of the EMT transcription factor SLUG and were correlated with survival of patients with glioblastoma (GBM). Functional mechanisms of SLUG regulation and the effects on primary human brain vascular pericytes (HBVP) were studied in vitro by measuring proliferation, cell motility and growth characteristics.

RESULTS

The number of PDGFR-β- and αSMA-positive pericytes did not change with increased malignancy nor showed an association with the survival of GBM patients. However, SLUG-expressing pericytes displayed considerable morphological changes in GBM-associated vessels, and TGF-β induced SLUG upregulation led to enhanced proliferation, motility and altered growth patterns in HBVP. Downregulation of SLUG or addition of a TGF-β antagonising antibody abolished these effects.

CONCLUSIONS

We provide evidence that in GA-Peris, elevated SLUG expression is mediated by TGF-β, a cytokine secreted by most glioma cells, indicating that the latter actively modulate neovascularisation not only by modulating endothelial cells, but also by influencing pericytes. This process might be responsible for the formation of an unstructured tumour vasculature as well as for the breakdown of the blood-brain barrier in GBM.

A Computational Systems Biology Approach Identifies SLUG as a Mediator of Partial Epithelial-Mesenchymal Transition (EMT)

Epithelial-mesenchymal plasticity comprises reversible transitions among epithelial, hybrid epithelial/mesenchymal (E/M) and mesenchymal phenotypes, and underlies various aspects of aggressive tumor progression such as metastasis, therapy resistance, and immune evasion. The process of cells attaining one or more hybrid E/M phenotypes is termed as partial epithelial mesenchymal transition (EMT). Cells in hybrid E/M phenotype(s) can be more aggressive than those in either fully epithelial or mesenchymal state. Thus, identifying regulators of hybrid E/M phenotypes is essential to decipher the rheostats of phenotypic plasticity and consequent accelerators of metastasis. Here, using a computational systems biology approach, we demonstrate that SLUG (SNAIL2) - an EMT-inducing transcription factor - can inhibit cells from undergoing a complete EMT and thus stabilize them in hybrid E/M phenotype(s). It expands the parametric range enabling the existence of a hybrid E/M phenotype, thereby behaving as a phenotypic stability factor. Our simulations suggest that this specific property of SLUG emerges from the topology of the regulatory network it forms with other key regulators of epithelial-mesenchymal plasticity. Clinical data suggest that SLUG associates with worse patient prognosis across multiple carcinomas. Together, our results indicate that SLUG can stabilize hybrid E/M phenotype(s).

Transactivation of Herpes Simplex Virus 1 (HSV-1) Infected Cell Protein 4 Enhancer by Glucocorticoid Receptor and Stress-Induced Transcription Factors Requires Overlapping Krüppel-Like Transcription Factor 4/Sp1 Binding Sites

Following acute infection, herpes simplex virus 1 (HSV-1) lytic cycle viral gene expression is silenced; consequently, lifelong latency in neurons is established. Certain external stimuli that trigger reactivation from latency also activate the glucocorticoid receptor (GR). The synthetic corticosteroid dexamethasone, but not a GR-specific antagonist, increases the frequency of explant-induced reactivation from latency and stimulates productive infection. Furthermore, dexamethasone increases expression of cellular transcription factors in trigeminal ganglionic neurons: for example, SLUG and three Krüppel-like transcription factor (KLF) family members, KLF4, KLF15, and promyelocytic leukemia zinc finger protein (PLZF). Consequently, we hypothesized that stress-induced transcription factors stimulate expression of ICP4, a viral transcriptional regulator required for productive infection. New studies demonstrated that GR and KLF4, PLZF, or SLUG cooperatively transactivate the ICP4 enhancer upstream of a minimal promoter in monkey kidney cells (Vero) and mouse neuroblastoma cells (Neuro-2A). Strikingly, mutagenesis of two KLF4/Sp1 binding sites reduced GR- plus KLF4-, PLZF-, or SLUG-mediated transactivation to basal levels. A consensus enhancer (E)-Box adjacent to a KLF4/Sp1 binding site was also required for GR- and SLUG-, but not KLF family member-, mediated transactivation of the ICP4 promoter. Chromatin immunoprecipitation studies (ChIP) revealed GR and stress-induced transcription factors occupy ICP4 enhancer sequences. Conversely, specific binding was generally reduced in the KLF4/Sp1 mutant. Furthermore, GR and SLUG occupancy of ICP4 enhancer sequences was reduced in the E-Box mutant. Based on these studies, we suggest stressful stimuli can trigger productive infection because GR and specific stress-induced transcription factors activate ICP4 expression.IMPORTANCE Certain stressful stimuli activate the glucocorticoid receptor (GR) and increase the incidence of herpes simplex virus 1 (HSV-1) reactivation from latency. For example, a corticosteroid antagonist impairs productive infection and virus shedding following explant of trigeminal ganglia from latently infected mice. Infected cell protein 4 (ICP4) is the only immediate early viral transcriptional regulator required for productive infection, suggesting stressful stimuli stimulate ICP4 expression. New studies revealed GR and stress-induced transcription factors identified during reactivation from latency, SLUG and three Krüppel-like transcription factor family members (KLF4, KLF15, and promyelocytic leukemia zinc finger protein), cooperatively transactivate the ICP4 enhancer. Two KLF4 consensus binding sites were crucial for cooperative transactivation of the ICP4 enhancer. A consensus enhancer-box also mediated cooperative transactivation of the ICP4 enhancer by GR and SLUG. The ability of GR and stress-induced transcription factors to transactivate ICP4 enhancer activity is predicted to trigger productive infection following stressful stimuli.

MicroRNA-4287 is a novel tumor suppressor microRNA controlling epithelial-to mesenchymal transition in prostate cancer

Prostate cancer (PCa) is a significant cause of male morbidity in the United States. Despite recent advances in diagnosis and therapeutic interventions, significant fraction of cases still progress to an advanced stage. Various genetic/epigenetic elements that facilitate this progression are not yet completely known and the mechanism that favors advanced disease is an area of investigation. A characteristic feature associated with progressive disease is deletion of chromosome 8p (chr8p) region, that harbors tumor-suppressor NKX3.1. Previous studies from our group has shown that there are cluster of microRNAs (miRNAs) located within this region whose loss favors advanced, metastatic disease. miR-4287 is a novel miRNA located within this region that has not been studied before. In the present study, we analyzed the role of miR-4287 in PCa using clinical tissues and cell lines. We observed that miR-4287 is significantly downregulated in patient-derived tumor tissues. Receiver operating curve (ROC) analysis showed that miR-4287 distinguishes prostate cancer from normal with a specificity of 88.24% and with an Area under the curve (AUC) of 0.66. Further, we found that miR-4287 levels correlate inversely with patients' serum prostate-specific antigen levels. Ectopic over-expression of miR-4287 in PCa cell lines showed that miR-4287 plays a tumor suppressor role. miR-4287 led to an increase in G2/M phase of cell cycle in PCa cell lines. Further, ectopic miR-4287 inhibited PCa epithelial-to-mesenchymal transition (EMT) by directly repressing SLUG and stem cell marker CD44. Since miR-4287 specifically targets metastasis pathway mediators, miR-4287 has potential diagnostic and therapeutic significance in preventing advanced, metastatic disease.

MiR-203a-3p Inhibits Pancreatic Cancer Cell Proliferation, EMT, and Apoptosis by Regulating SLUG

OBJECTIVE

The aim of the present research is to study the roles of miR-203a-3p on cell proliferation, migration, invasion, and epithelial-mesenchymal transition in pancreatic cancer.

METHODS

Transcription profiles were acquired from Gene Expression Omnibus database, which was used to screen out the differentially expressed microRNAs and messenger RNAs in pancreatic cancer. Pancreatic cancer tissues were used to verify the bioinformatics results by quantitative real-time polymerase chain reaction. The relationship between miR-203a-3p and SLUG was examined by TargetScan software, dual-luciferase reporter assay, and RNA immunoprecipitation. The Cell Counting Kit-8, wound healing, and transwell assays were conducted to investigate the proliferation, migration, and invasion capability of pancreatic cancer cells, respectively. The expression of epithelial-mesenchymal transition-related proteins was determined by the Western blot assay. Xenograft assay was performed to verify findings from in vitro assays.

RESULTS

Bioinformatic analysis found that a total of 113 microRNAs and 1749 messenger RNAs expressed differentially in pancreatic cancer tissues. Among these microRNAs, the expression of miR-203a-3p was significantly decreased in both pancreatic cancer tissues and cells. On the other hand, the SLUG expression was remarkably upregulated in pancreatic cancer tissues and cells in comparison with normal tissues and cells. Moreover, TargetScan software, dual-luciferase reporter assay, and RNA immunoprecipitation revealed that SLUG was a target of miR-203a-3p. The upregulation of miR-203a-3p expression inhibited the proliferation, migration, and invasion ability of pancreatic cancer cells by suppressing the epithelial-mesenchymal transition process via sponging SLUG.

CONCLUSION

These findings indicate that downregulation of miR-203a-3p in pancreatic cancer cells leads to high expression of SLUG, which promotes epithelial-mesenchymal transition process and induces cancer progression.

Deubiquitinase USP20 promotes breast cancer metastasis by stabilizing SNAI2

In this study, Li et al. conducted comprehensive gain- and loss-of-function screens using a human DUB cDNA library of 65 genes and an siRNA library of 98 genes, and identified USP20 as a deubiquitinase (DUB) that regulates a metastasis-promoting transcription factor, SNAI2, ubiquitination, and stability.

SNAI2/SLUG, a metastasis-promoting transcription factor, is a labile protein that is degraded through the ubiquitin proteasome degradation system. Here, we conducted comprehensive gain- and loss-of-function screens using a human DUB cDNA library of 65 genes and an siRNA library of 98 genes, and identified USP20 as a deubiquitinase (DUB) that regulates SNAI2 ubiquitination and stability. Further investigation of USP20 demonstrated its function in promoting migration, invasion, and metastasis of breast cancer. USP20 positively correlates with SNAI2 protein level in breast tumor samples, and higher USP20 expression is associated with poor prognosis in ER⁻ breast cancer patients.

The role of the redox/miR-6855-3p/PRDX5A axis in reversing SLUG-mediated BRCA2 silencing in breast cancer cells

BACKGROUND

We have previously shown that the zinc finger transcription repressor SNAI2 (SLUG) represses tumor suppressor BRCA2-expression in non-dividing cells by binding to the E2-box upstream of the transcription start site. However, it is unclear how proliferating breast cancer (BC) cells that has higher oxidation state, overcome this repression. In this study, we provide insight into the mechanism of de-silencing of BRCA2 gene expression by PRDX5A, which is the longest member of the peroxiredoxin5 family, in proliferating breast cancer cells.

METHODS

We used cell synchronization and DNA affinity pulldown to analyze PRDX5A binding to the BRCA2 silencer. We used oxidative stress and microRNA (miRNA) treatments to study nuclear localization of PRDX5A and its impact on BRCA2-expression. We validated our findings using mutational, reporter assay, and immunofluorescence analyses.

RESULTS

Under oxidative stress, proliferating BC cells express PRDX5 isoform A (PRDX5A). In the nucleus, PRDX5A binds to the BRCA2 silencer near the E2-box, displacing SLUG and enhancing BRCA2-expression. Nuclear PRDX5A is translated from the second AUG codon in frame to the first AUG codon in the PRDX5A transcript that retains all exons. Mutation of the first AUG increases nuclear localization of PRDX5A in MDA-MB-231 cells, but mutation of the second AUG decreases it. Increased mitronic hsa-miRNA-6855-3p levels under oxidative stress renders translation from the second AUG preferable. Mutational analysis using reporter assay uncovered a miR-6855-3p binding site between the first and second AUG codon in the PRDX5A transcript. miR-6855-3p mimic increases accumulation of nuclear PRDX5A and inhibits reporter gene translation.

CONCLUSION

Oxidative stress increases miR-6855-3p expression and binding to the inter-AUG sequence of the PRDX5A transcript, promoting translation of nuclear PRDX5A. Nuclear PRDX5A relieves SLUG-mediated BRCA2 silencing, resulting in increased BRCA2-expression.

NOTCH4 maintains quiescent mesenchymal-like breast cancer stem cells via transcriptionally activating SLUG and GAS1 in triple-negative breast cancer

Rationale: NOTCH4 receptor has been implicated in triple-negative breast cancer (TNBC) development and breast cancer stem cell (BCSC) regulation. However, the potential of NOTCH4 as a BCSC marker and the underlying mechanisms remain unclear.

Methods: In this study, we determined the expression and activation of NOTCH4 in breast cancer cell lines and tumor samples by qRT-PCR, western blotting and immunohistochemistry. Subsequently, in vitro and in vivo serial dilution experiments were performed to demonstrate the application of NOTCH4 as an efficient mesenchymal-like (ML)-BCSC marker in TNBC. Stable overexpression of activated NOTCH4 and knockdown cell lines were established using lentivirus. RNA-seq and qRT-PCR were employed to reveal the downstream effectors of NOTCH4, followed by dual-luciferase reporter and chromatin immunoprecipitation assays to identify the genuine binding sites of NOTCH4 on SLUG and GAS1 promoters. Transwell assay, mammosphere formation and chemoresistance experiments were performed to determine the effects of SLUG, GAS1 and NOTCH4 on the mesenchymal-like characteristics of TNBC cells. Survival analysis was used to study the relation of NOTCH4, SLUG and GAS1 with prognosis of breast cancer.

Results: NOTCH4 is aberrantly highly expressed and activated in TNBC, which contributes to the maintenance of ML-BCSCs. Furthermore, NOTCH4 shows significantly higher efficiency in labeling ML-BCSCs than the currently commonly used CD24^-CD44⁺ marker. Mechanistically, NOTCH4 transcriptionally upregulates SLUG and GAS1 to promote EMT and quiescence in TNBC, respectively. The effects of NOTCH4 can be mimicked by simultaneous overexpression of SLUG and GAS1. Moreover, SLUG is also involved in harnessing GAS1, a known tumor suppressor gene, via its anti-apoptotic function.

Conclusions: Our findings reveal that the NOTCH4-SLUG-GAS1 circuit serves as a potential target for tumor intervention by overcoming stemness of ML-BCSCs and by conquering the lethal chemoresistance and metastasis of TNBC.

The Aryl Hydrocarbon Receptor Is Expressed in Thyroid Carcinoma and Appears to Mediate Epithelial-Mesenchymal-Transition

Aryl hydrocarbon receptor (AhR) is expected to promote initiation, progression and invasion of cancer cells regulating proliferation, differentiation, gene expression, inflammation, cell motility and migration. Furthermore, an immunosuppressant function of AhR has been recognized. This study evaluated AhR expression and its role in thyroid cancer progression. AhR expression was assessed by qPCR in 107 thyroid cancer samples (90 PTCs, 11 MTCs, 6 ATCs), and by immunohistochemistry in 41 PTCs. To estimate receptor activation, the expression of target genes CYP1A1 and CYP1B1 was measured. AhR functional effects were evaluated in kynurenine-stimulated FTC-133 and BcPap cell lines by analyzing the expression of genes involved in EMT and cell motility. AhR mRNA expression resulted significantly higher in all the analyzed thyroid cancer samples compared to normal thyroid and a statistically significant correlation with CYP1B1 was detected. Kynurenine-stimulated FTC-133 and BcPap showed the activation of a specific AhR-driven EMT program characterized by E-cadherin decrease and SLUG, N-cadherin and fibronectin increase, resulting in boost of cell motility and invasion. This study confirmed the importance of the IDO1-Kyn-AhR pathway in thyroid cancer tumorigenesis, suggesting an AhR pivotal role in mediating an immunosuppressive microenvironment and favoring the acquisition of a mesenchymal phenotype that could promote invasiveness and metastasis.

Downregulation of ABI2 expression by EBV-miR-BART13-3p induces epithelial-mesenchymal transition of nasopharyngeal carcinoma cells through upregulation of c-JUN/SLUG signaling

Existing evidence has shown that circulating Epstein-Barr virus (EBV)-miR-BART13-3p is highly expressed in plasma of nasopharyngeal carcinoma (NPC) patients, especially among patients with advanced diseases. However, the exact role that EBV-miR-BART13-3p plays in the development of NPC remains poorly understood. Here we show that up-regulated expression of EBV-miR-BART13-3p leads to increased capacity in migration and invasion of NPC cells in vitro and causes tumor metastasis in vivo. Furthermore, we find that EBV-miR-BART13-3p directly targets ABI2, known as a tumor suppressor and a cell migration inhibitor, drives epithelial-mesenchymal transition (EMT) by activating c-JUN/SLUG signaling pathway. Silencing ABI2 shows similar effects to overexpression of EBV-miR-BART13-3p, whereas reconstitution of ABI2 resulted in a phenotypic reversion, highlighting the role of ABI2 in EBV-miR-BART13-3p-driven metastasis in NPC. Besides, expression levels of ABI2 in NPC tissue samples correlate with N stages of NPC patients. Taken together, these results suggest a novel mechanism by which ABI2 downregulation by EBV-miR-BART13-3p promotes EMT and metastasis of NPC via upregulating c-JUN/SLUG signaling pathway.

SLUG Directs the Precursor State of Human Brain Tumor Stem Cells

In glioblastoma (GBM), brain tumor stem cells (BTSCs) encompass heterogenous populations of multipotent, self-renewing, and tumorigenic cells, which have been proposed to be at the root of therapeutic resistance and recurrence. While the functional significance of BTSC heterogeneity remains to be fully determined, we previously distinguished relatively quiescent stem-like precursor state from the more aggressive progenitor-like precursor state. In the present study, we hypothesized that progenitor-like BTSCs arise from stem-like precursors through a mesenchymal transition and drive post-treatment recurrence. We first demonstrate that progenitor-like BTSCs display a more mesenchymal transcriptomic profile. Moreover, we show that both mesenchymal GBMs and progenitor-like BTSCs are characterized by over-activated STAT3/EMT pathways and that SLUG is the primary epithelial to mesenchymal transition (EMT) transcription factor directly regulated by STAT3 in BTSCs. SLUG overexpression in BTSCs enhances invasiveness, promotes inflammation, and shortens survival. Importantly, SLUG overexpression in a quiescent stem-like BTSC line enhances tumorigenesis. Finally, we report that recurrence is associated with SLUG-induced transcriptional changes in both BTSCs and GBM patient samples. Collectively, our findings show that a STAT3-driven precursor state transition, mediated by SLUG, may prime BTSCs to initiate more aggressive mesenchymal recurrence. Targeting the STAT3/SLUG pathway may maintain BTSCs in a quiescent stem-like precursor state, delaying recurrence and improving survival in GBM.

LncRNA NONHSAT113026 represses renal cell carcinoma tumorigenesis through interacting with NF-κB/p50 and SLUG

Renal cell carcinoma (RCC) is one of the most lethal urological malignancies, yet its pathogenesis remains unclear. Here, we reported a long non-coding RNA (lncRNA), NONHSAT 113026 (NOAT113026), which may play an important role in the pathogenesis of RCC. The expression level of NOAT113026 was estimated by qPCR from 76 pairs of RCC and non-tumor (NT) samples. The correlation between NOAT113026 and clinical data of RCC patients was analyzed. NOAT113026 was overexpressed in 786-O and ACHN cell lines by lentivirus-mediated technology and the oncological behavioral changes of RCC cells were observed along with tumorigenicity in experimental nude mice. Compared to the adjacent tissues, NOAT113026 was noticeably downregulated in RCC. Survival analysis showed that the lower the expression level of NOAT113026 was, the shorter the disease-free survival and overall survival in RCC would be. Overexpression of NOAT113026 can decrease the ability of cell migration, invasion, proliferation, and colony formation by regulating NF-κB/p50 and SLUG through a mechanism that involves lncRNA-mRNA interactions. In conclusion, our data suggest that NOAT113026 could be a carcinostatic RNA in RCC, which may serve as a potential prognostic factor and a promising therapeutic target for malignant RCC.

Fibronectin Regulation of Integrin B1 and SLUG in Circulating Tumor Cells

Metastasis is the leading cause of cancer death worldwide. Circulating tumor cells (CTCs) are a critical step in the metastatic cascade and a good tool to study this process. We isolated CTCs from a syngeneic mouse model of hepatocellular carcinoma (HCC) and a human xenograft mouse model of castration-resistant prostate cancer (CRPC). From these models, novel primary tumor and CTC cell lines were established. CTCs exhibited greater migration than primary tumor-derived cells, as well as epithelial-to-mesenchymal transition (EMT), as observed from decreased E-cadherin and increased SLUG and fibronectin expression. Additionally, when fibronectin was knocked down in CTCs, integrin B1 and SLUG were decreased, indicating regulation of these molecules by fibronectin. Investigation of cell surface molecules and secreted cytokines conferring immunomodulatory advantage to CTCs revealed decreased major histocompatibility complex class I (MHCI) expression and decreased endostatin, C-X-C motif chemokine 5 (CXCL5), and proliferin secretion by CTCs. Taken together, these findings indicate that CTCs exhibit distinct characteristics from primary tumor-derived cells. Furthermore, CTCs demonstrate enhanced migration in part through fibronectin regulation of integrin B1 and SLUG. Further study of CTC biology will likely uncover additional important mechanisms of cancer metastasis.

SLUG/HIF1-α/miR-221 regulatory circuit in endometrial cancer

BACKGROUND AND PURPOSE

The pathogenesis of endometrial cancer (EC) involves many regulatory pathways including transcriptional regulatory networks supported by transcription factors and microRNAs only in part known. The aim of this retrospective study was to explore the possible correlation in the EC microenvironment between master regulators of complex phenomena such as steroid responsiveness through estrogen receptor alpha (ERα) and progesterone receptor (PR), epithelial-to-mesenchymal transition (supported by SLUG transcription factor), hypoxia (with hypoxia inducible factor-1 alpha, HIF-1α), and obesity that has been recognized as a EC risk factor.

METHODS

Formalin-Fixed Paraffin-Embedded (FFPE) blocks from University of Ferrara Pathology Archive were used and allocated into 2 groups according to their immunohistochemical positivity to ERα and PR, distinguishing the samples with a more benign prognosis (ERα⁺/PR⁺) from those with a poorer prognosis (ERα^-/PR^-). Immunohistochemistry for HIF1-α and SLUG was also performed. Body mass index (BMI) was registered at the time of diagnosis: patients with BMI ≥ 30 kg/m² were defined obese (OB). Total RNA was isolated for miR-221 analysis.

RESULTS

We showed a comparable percentage of HIF1-α and SLUG positive samples in the ERα⁺/PR⁺ and ERα^-/PR^- groups. However, the obesity factor impacted more in the ERα⁺/PR⁺ group since the ratio between OB and non-obese (NOB) patients with high expression of HIF1-α and SLUG was higher in ERα⁺/PR⁺ than in the ERα^-/PR^- group. miR-221 levels were significantly higher in the OB than NOB patients, and, also in this case, obesity impacted more in the ERα⁺/PR⁺ group.

CONCLUSIONS

A molecular circuit of mutual regulation between ERα, PR, HIF1-α, SLUG and miR-221 is feasible in the EC and was firstly suggested by our research. In this interplay miR-221 seems to be in a nodal point of the regulatory system that is particularly strengthened by the metabolic changes in obesity.

Prognostic value of epithelial-mesenchymal transition related genes: SLUG and QKI in breast cancer patients

Snail family zinc finger 2 (SLUG) is related to epithelial-mesenchymal transition (EMT). Quaking (QKI) is an RNA binding protein and has been indicated to have a relationship with EMT by recent studies. The prognostic value of SLUG and QKI in breast cancer patients still needs exploration. We conducted Immunohistochemistry (IHC) to evaluate the protein expression of SLUG and QKI and the prognostic value in 108 breast cancer (BC) patients. The Bc-GenExMiner database was used to compare the mRNA levels of two genes in different subgroups of BC patients. Kaplan-Meier plotter were used for survival data of SLUG and QKI gene. We also mined the cBioPortal database for co-expression analysis of QKI and EMT markers. Our results suggested that patients with higher expression of SLUG and QKI showed shorter overall survival time. The mRNA level of SLUG and QKI were higher in ER negative, PR negative, ≤ 51 y, and TNBC patients. SLUG mRNA showed no survival significance, while higher QKI mRNA expression level was correlated with worse clinical outcome in Kaplan-Meier Plotter database. The cBioPortal database showed that QKI was correlated to SLUG as well as other EMT markers like TWIST2, VIM, and ZEB2. QKI was indicated to be a potential prognostic marker for BC patients, and combined expression of SLUG and QKI showed the best prognostic value. Co-expression analysis indicated that QKI was likely to have a correlation with SLUG and EMT.

TBX3 promotes progression of pre-invasive breast cancer cells by inducing EMT and directly up-regulating SLUG

The acquisition of cellular invasiveness by breast epithelial cells and subsequent transition from ductal carcinoma in situ (DCIS) to invasive breast cancer is a critical step in breast cancer progression. Little is known about the molecular dynamics governing this transition. We have previously shown that overexpression of the transcriptional regulator TBX3 in DCIS‐like cells increases survival, growth, and invasiveness. To explore this mechanism further and assess direct transcriptional targets of TBX3 in a high‐resolution, isoform‐specific context, we conducted genome‐wide chromatin‐immunoprecipitation (ChIP) arrays coupled with transcriptomic analysis. We show that TBX3 regulates several epithelial–mesenchymal transition (EMT)‐related genes, including SLUG and TWIST1. Importantly, we demonstrate that TBX3 is a direct regulator of SLUG expression, and SLUG expression is required for TBX3‐induced migration and invasion. Assessing TBX3 by immunohistochemistry in early‐stage (stage 0 and stage I) breast cancers revealed high expression in low‐grade lesions. Within a second independent early‐stage non‐high‐grade cohort, we observed an association between TBX3 level in the DCIS and size of the invasive focus. Additionally, there was a positive correlation between TBX3 and SLUG, and TBX3 and TWIST1 in the invasive carcinoma. Pathway analysis revealed altered expression of several proteases and their inhibitors, consistent with the ability to degrade basement membrane in vivo. These findings strongly suggest the involvement of TBX3 in the promotion of invasiveness and progression of early‐stage pre‐invasive breast cancer to invasive carcinoma through the low‐grade molecular pathway. © 2019 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.

Expression of epithelial-mesenchymal transition regulators TWIST, SLUG and SNAIL in follicular thyroid tumours may relate to widely invasive, poorly differentiated and distant metastasis

AIMS

To assess the expression of epithelial-mesenchymal transition (EMT) regulators in follicular thyroid tumours.

METHODS AND RESULTS

The expression of E-cadherin (E-CAD) and transcription factors TWIST, SLUG and SNAIL in follicular thyroid tumours was examined by immunohistochemistry in tissue samples, including 18 follicular adenomas (FA), 12 minimally invasive follicular thyroid carcinomas (MI-FTC), 16 widely invasive follicular thyroid carcinomas (WI-FTC), 10 poorly differentiated follicular thyroid carcinomas (PDTC) and six anaplastic thyroid carcinomas (ATC). Metastatic tumour tissues from six of these cases were also examined. The results showed an increasing expression trend of EMT regulators in a panel of follicular tumour cases with a spectrum of morphological subtypes from low- to high-risk malignancy. The expression of EMT regulators was higher in the WI-FTC, PDTC and ATC groups but focal and lower in the FA and MI-FTC groups. Different expression intensity of E-CAD and EMT regulators at the tumour centre part and the invasive front (IF) was observed. The loss of E-CAD and expression of EMT regulators was significantly correlated with distant metastasis and vascular invasion (VI) in the well-differentiated follicular carcinoma (WD-FTC), and six tumours of metastatic sites also showed variables positive for EMT regulators. The disease-free survival analysis showed an apparent relationship between the expression of EMT regulators and the tumour disease-free outcomes in WD-FTC.

CONCLUSIONS

Our study supported the role of EMT in the development of follicular thyroid carcinoma and indicated that EMT regulatory proteins may play an important role in WD-FTC that are widely invasive and exhibit distant metastasis.

FOXN2 is downregulated in breast cancer and regulates migration, invasion, and epithelial- mesenchymal transition through regulation of SLUG

Introduction

Forkhead box (FOX) N2 (FOXN2), a member of FOX protein family, has been reported to play critical roles in some types of cancers. However, the expression and function of FOXN2 in breast cancer remain unclear.

Methods

In the present work, we explored the detailed molecular mechanism of FOXN2 in breast cancer. We performed RT-qPCR and Western blotting analysis to detect the expression of FOXN2 in breast cancer. Colony formation assay, CCK-8 assay, wound healing assay, and Transwell assay were used to determine the effect of FOXN2 on cell proliferation, migration, and invasion in breast cancer.

Results

Our results demonstrated that FOXN2 was downregulated in breast cancer tissues and cell lines. Downregulation of FOXN2 was correlated with tumor size, pathological grade, and lymph node metastasis. The in vitro experiments revealed that the ectopic expression of FOXN2 significantly suppressed the proliferation, migration, and invasiveness of breast cancer cells, and inhibition of FOXN2 promoted the proliferation, migration, and invasiveness of breast cancer cells. Moreover, inhibition of FOXN2 facilitated epithelial–mesenchymal transition (EMT) through regulation of SLUG.

Conclusion

Taken together, our results showed for the first time that FOXN2 plays an essential role in cell proliferation and invasion. Thus, FOXN2 may be an attractive therapeutic target for the treatment of breast cancer.

USP5 promotes epithelial-mesenchymal transition by stabilizing SLUG in hepatocellular carcinoma

Rationale: The role of SLUG in epithelial-mesenchymal transition during tumor progression has been thoroughly studied, but its precise regulation remains poorly explored. Methods: The affinity purification, mass spectrometry and CO-IP were performed to identify the interaction between SLUG and ubiquitin-specific protease 5 (USP5). Cycloheximide chase assays and deubiquitination assays confirmed that the effect of USP5 on the deubiquitin of SLUG. The dual-luciferase reporter and chromatin immunoprecipitation assays were employed to observe the direct transcriptional regulation of E-cadherin by SLUG effected by USP5. EMT related markers was detected by western blotting and immunofluorescence. Molecular docking, SPR sensor (biacore) and co-location were detected to prove Formononetin targets USP5. Bioinformatics analysis was used to study the relation of USP5 and SLUG to malignancy degree of HCC. Cell migration, invasion in HCC cells and xenografts model in nude mouse were conducted to detect the promotion of USP5 and the inhibition of Formononetin on EMT. Results: USP5 interacts with and stabilizes SLUG to regulate its abundance through USP5 deubiquitination activities in epithelial-mesenchymal transition (EMT) of hepatocellular carcinoma (HCC). USP5 is highly expressed and positively correlated with SLUG expression in HCC with high malignancy. Knockdown of USP5 inhibits SLUG deubiquitination and inhibits HCC cells proliferation, metastasis, and invasion, while overexpression of USP5 promotes SLUG stability and EMT in vitro and in vivo. Through virtual screening, we found that Formononetin exhibits excellent binding to USP5. Moreover, Formononetin inhibits deubiquitinating activities of USP5 to SLUG and consequently impedes the EMT and malignant progression of HCC. Conclusion: Our findings reveal that USP5 serve as a potential target for tumor intervention and provide a preliminary antitumor therapy for inhibit EMT by targeting USP5 or its interaction with SLUG in HCC.

Expression of selected epithelial-mesenchymal transition transcription factors in serous borderline ovarian tumors and type I ovarian cancers

Epithelial ovarian neoplasms are a heterogeneous group including tumor subsets with distinct clinicopathologic and molecular features. Recent evidence from molecular and genomic studies suggests that whereas low-grade serous carcinomas and high-grade serous carcinomas likely develop on two separate pathways, the low-grade serous carcinomas and serous borderline ovarian tumors may represent various stages of the same developmental continuum. The transformation of borderline ovarian tumors into an invasive neoplasm is associated with an array of molecular changes, inter alia controlled by p53 and PI3K/Akt pathway, as well as with a decrease in E-cadherin expression. The latter implies that epithelial-mesenchymal transition is a critical determinant of borderline ovarian tumor invasiveness. The aim of this study was to analyze the expression of transcription factors involved in epithelial-mesenchymal transition: SNAIL, SLUG, TWIST 1, TWIST 2, ZEB 1, and ZEB 2 in borderline tumors and type I ovarian cancers. The study included tissue specimens from 42 patients with histopathologically verified ovarian masses. The expressions for SLUG, TWIST 1, ZEB1, and ZEB 2 were scored based on the nuclear staining, and the expressions of SNAIL and TWIST 2 based on the cytoplasmic and/or nuclear staining. The proportions of ovarian tumors with the immunoexpression of the epithelial-mesenchymal transition transcription factors were 85.7% for SNAIL, 100% for SLUG, 9.5% for TWIST 1, 95.2% for TWIST 2, 23.8% for ZEB 1, and 0% for ZEB 2. The expression patterns of SNAIL, SLUG, TWIST, and ZEB identified in this study suggest that both serous borderline ovarian tumors and type I ovarian cancers undergo dynamic epithelial-mesenchymal interconversions. Our findings obtained in the two groups of tumors which shared some etiopathogenic pathways imply that the expression of the epithelial-mesenchymal transition transcription factors may be activated at early stages of the epithelial-mesenchymal transition, and thus these molecules may play a pivotal role in the development of both serous borderline ovarian tumors and type I ovarian cancer.

SPANXA suppresses EMT by inhibiting c-JUN/SNAI2 signaling in lung adenocarcinoma

SPANXA (Sperm Protein Associated with the Nucleus on the X-chromosome, family members A1/A2) acts as a cancer-testis antigen expressed in normal testes, but dysregulated in various tumors. We found that SPANXA is highly expressed in low-invasive CL1-0 cells compared with isogenous high-invasive CL1-5 cells. SPANXA was preferably expressed in tumor tissues and associated with the prolonged survival of lung adenocarcinomas. SPANXA suppressed the invasion and metastasis of lung cancer cells in vitro and in vivo. By the expression microarray and pathway analysis, we found that the SPANXA-altered genes were enriched in the epithelial–mesenchymal transition (EMT) pathway. SPANXA reduced SNAI2 expression resulted in up-regulating E-cadherin. c-JUN acts as the positive-regulator of EMT. Silencing SPANXA increased c-JUN mRNA expression and blockage of c-JUN led to SNAI2 down-regulation. Our results clearly characterized SPANXA as an EMT inhibitor by suppressing c-JUN-SNAI2 axis in lung adenocarcinoma.

miR-124 represses the mesenchymal features and suppresses metastasis in Ewing sarcoma

Metastasis is the most powerful predictor of poor outcome of Ewing sarcoma (ES). Thus, identification of new molecules involved in tumor metastasis is of crucial importance to reduce morbidity and mortality of this devastating disease. In this study, we found that miR-124, a highly conserved miRNA, was suppressed in ES tissues and might be associated with tumor metastasis through suppressing its mesenchymal features. Overexpression of miR-124 suppressed the invasion of ES cells in vitro and tumor metastasis in vivo, which might be achieved through suppressing its mesenchymal features, as overexpression of miR-124 could repress the mesenchymal genes expression, and inhibit cell differentiation to mesenchymal lineages in ES cells. However, when SLUG was experimentally restored in these cells, mesenchymal features including suppressed expression of mesenchymal genes and decreased invasive ability were observed. We also found that cyclin D2 (CCND2) was a novel target gene of miR-124, and was directly involved in miR-124-mediated suppressive effects on cell growth. Lastly, we found that treatment with 5-Aza-CdR restored the expression of miR-124, accompanied with suppressed cell proliferation, invasion and mesenchymal features of ES cells, which demonstrated that hypermethylation might be involved in the regulation of miR-124 expression. Collectively, our data suggest that hypermethylation-mediated suppression of miR-124 might be involved in the tumor initiation and metastasis through suppressing the mesenchymal features of ES cells.

Oncostatin M suppresses metastasis of lung adenocarcinoma by inhibiting SLUG expression through coordination of STATs and PIASs signalings

Oncostatin M (OSM) is linked with multiple biological responses including growth and differentiation. Previous reports showed inhibitory effects of OSM in tumor progression while others showed promoting effects. The dual role of OSM in the development of various cancers is still unclear. We previously described OSM-mediated SLUG suppression, leading to repressed metastasis of lung adenocarcinoma (LAC) cells. However, the underlying mechanism remains elusive. Here, we showed that OSM suppresses SLUG express in LAC cells through a STAT1-dependent transcriptional inhibition. Knockdown of STAT1 reversed the OSM-suppressed SLUG expression and rescued the OSM-mediated inhibition of cell proliferation, migration, and invasion in vitro, as well as pulmonary metastasis in vivo. STAT1 suppressed SLUG transcription through binding to its promoter region in response to OSM. Furthermore, PIAS4, a co-repressor of STAT, and HDAC1 were able to bind to STAT1 on SLUG promoter region, resulting in reduced H3K9 acetylation and suppressed SLUG expression upon OSM treatment. In contrast, PIAS3 bound to activated STAT3, another effector of OSM, in response to OSM and blocked the binding of STAT3 to SLUG promoter region, preventing STAT3-dependent activation of SLUG transcription. Our findings suggested that OSM suppresses SLUG expression and tumor metastasis of LAC through inducing the inhibitory effect of the STAT1-dependent pathway and suppressing the activating effect of STAT3-dependent signaling. These results can serve as a scientific basis for the potential therapeutic intervention of OSM in cancer cells.

Paradoxical expression pattern of the epithelial mesenchymal transition-related biomarkers CD44, SLUG, N-cadherin and VSIG1/Glycoprotein A34 in gastrointestinal stromal tumors

AIM

To evaluate the immunohistochemical (IHC) expression of five biomarkers, commonly involved in epithelial mesenchymal/mesenchymal epithelial transition (EMT/MET), in gastrointestinal stromal tumors (GISTs).

METHODS

In 80 consecutive GISTs the IHC examinations were performed using the EMT-related antibodies E-cadherin, N-cadherin, SLUG, V-set and immunoglobulin domain containing 1 (VSIG1) and CD44.

RESULTS

The positivity rate was 88.75% for SLUG, 83.75% for VSIG1, 36.25% for CD44 and 10% for N-cadherin. No correlation was noted between the examined markers and clinicopathological parameters. Nuclear positivity for SLUG and VSIG1 was observed in all cases with distant metastasis. The extra-gastrointestinal stromal tumors (e-GISTs) expressed nuclear positivity for VSIG1 and SLUG, with infrequent positivity for N-cadherin and CD44. The low overall survival was mainly dependent on VSIG1 negativity (P = 0.01) and nuclear positivity for SLUG and/or CD44.

CONCLUSION

GIST aggressivity may be induced by nuclear up-regulation of SLUG and loss or cytoplasm-to-nuclear translocation of VSIG1. SLUG and VSIG1 may act as activated nuclear transcription factors. The CD44, but not N-cadherin, might also have an independent prognostic value in these tumors. The role of the EMT/MET-related transcription factors in the evolution of GISTs, should be revisited with a larger dataset. This is the first study exploring the IHC pattern of VSIG1 in GISTs.

Role of human rhinovirus in triggering human airway epithelial-mesenchymal transition

Background

Structural changes in the airways, collectively referred to as airway remodeling, are a characteristic feature of asthma, and are now known to begin in early life. Human rhinovirus (HRV)-induced wheezing illnesses during early life are a potential inciting stimulus for remodeling. Increased deposition of matrix proteins causes thickening of the lamina reticularis, which is a well-recognized component of airway remodeling. Increased matrix protein deposition is believed to be due to the presence of increased numbers of activated mesenchymal cells (fibroblasts/myofibroblasts) in the subepithelial region of asthmatic airways. The origin of these increased mesenchymal cells is not clear, but one potential contributor is the process of epithelial-mesenchymal transition (EMT). We hypothesized that HRV infection may help to induce EMT.

Methods

We used the BEAS-2B human bronchial epithelial cells line, which uniformly expresses the major group HRV receptor, to examine the effects of stimulation with HRV alone, transforming growth factor-β1 (TGF-β1), alone, and the combination, on induction of changes consistent with EMT. Western blotting was used to examine expression of epithelial and mesenchymal phenotypic marker proteins and selected signaling molecules. Cell morphology was also examined.

Results

In this study, we show that two different strains of HRV, which use two different cellular receptors, are each capable of triggering phenotypic changes consistent with EMT. Moreover, both HRV serotypes synergistically induced changes consistent with EMT when used in the presence of TGF-β1. Morphological changes were also most pronounced with the combination of HRV and TGF-β1. Viral replication was not essential for phenotypic changes. The synergistic interactions between HRV and TGF-β1 were mediated, at least in part, via activation of mitogen activated protein kinase pathways, and via induction of the transcription factor SLUG.

Conclusions

These data support a role for HRV in the induction of EMT, which may contribute to matrix protein deposition and thickening of the lamina reticularis in airways of patients with asthma.

Urocortin attenuates TGFβ1-induced Snail1 and slug expressions: inhibitory role of Smad7 in Smad2/3 signaling in breast cancer cells

Corticortropin-releasing hormone (CRH) family are multifunctional endocrine-factors that regulate proliferation, apoptosis, and migration of various types of cancer cells. Deregulation of the transforming growth factor β1(TGFβ1) signal transduction promotes aggressive metastatic properties in late-stage breast cancers. We previously have demonstrated in breast cancer cell line that CRH suppressed TGFβ1-induced Epithelial-Mesenchymal Transition (EMT) via induction of E-cadherin. Our present data in MCF-7 and MDA-MB-231 cells showed that Urocortin (Ucn, a member of CRH family) inhibited TGFβ1 signaling by reducing Smad2/3 activation and subsequent nuclear translocation through increasing Smad7 expression, leading to downregulation of Snail1 and Slug, the two EMT promoters. We further found that Antalarmin (CRH receptor type 1, CRHR1 antagonist) and Antisauvagine-30 (CRH receptor type2, CRHR2 antagonist) abrogated the effects of Ucn on TGFβ1 signaling, implying that both active CRHR1 and CRHR2 participate in Ucn-repressed TGFβ1 signaling. Our findings, for the fist time, identify Ucn as a potential mediator that inhibits oncogenic signaling by TGFβ1 and suggest that activating CRHR1 and R2 may prove effective in diminishing breast cancer progression stimulated by TGFβ1.

SLUG expression is an indicator of tumour recurrence in high-grade endometrial carcinomas

AIMS

To investigate how SNAIL and SLUG were involved in the nature of high-grade endometrial carcinomas (grade 3 endometrioid carcinoma, serous carcinoma and clear cell carcinoma), we analysed the correlation of their expression status with clinicopathological characteristics and evaluated their prognostic significance.

METHODS AND RESULTS

We performed immunohistochemical staining in 52 high-grade endometrial carcinomas. Expression status of SNAIL and SLUG was classified into a high expression (positive in more than 50% of the tumour cells) and a low expression. Thirteen cases (25%) showed a high expression of SLUG, whereas all 52 cases showed a low expression of SNAIL. High expression of SLUG was correlated significantly with tumour recurrence (P = 0.0203) and aberrant p53 expression (P = 0.000559). Overall survival was worse in patients with high SLUG expression at all stages (P = 0.0327) and in those who underwent adjuvant therapy (P = 0.00963). Among the patients with complete tumour resection, high SLUG expression was associated with worse recurrence-free survival (RFS) in the patients at all stages (P = 0.00264), at stages III/IV (P = 0.0146), and who underwent adjuvant therapy (P = 0.000743). SLUG expression was identified as an independent factor of RFS by multivariate analysis (hazard ratio 5.938, 95% confidence interval 1.251-28.18, P = 0.025).

CONCLUSIONS

SLUG expression could be correlated with TP53 mutational status and could be involved in therapeutic resistance resulting in tumour recurrence. A high expression level of SLUG can be an indicator of recurrence and a therapeutic target for long-term remission in high-grade endometrial carcinomas.

LncRNA MALAT1 exerts oncogenic functions in lung adenocarcinoma by targeting miR-204

Accumulating evidence indicates that the lncRNAs play a critical role in cancer progression and metastasis. In this study, we found that MALAT1 upregulation was associated with larger tumor size and lymph-node metastasis, and also correlated with shorter overall survival of lung adenocarcinoma patients. Furthermore, MALAT1 promotes EMT and metastasis of lung adenocarcinoma cells in vitro and in vivo. In particular, MALAT1 upregulated the expression of miR-204 target gene SLUG through competitively 'spongeing' miR-204. In summary we unveil a branch of the MALAT1/miR-204/SLUG pathway that regulates the progression of lung adenocarcinoma.

Curcumin suppresses 4-hydroxytamoxifen resistance in breast cancer cells by targeting SLUG/Hexokinase 2 pathway

Triple negative breast cancer (TNBC) is the hardest breast cancer subtype to treat due to lacking therapeutic target and treatment options. In this study, we found that SLUG expression was much higher in TNBC MDA-MB-231 cells than estrogen receptor alpha (ERα) positive breast cancer MCF7 cells. 4-hydroxytamoxifen (4-OHT) promoted SLUG expression, which was blocked by curcumin. Further investigation showed that SLUG activated the transcription of hexokinase-2 (HK2) by binding to HK2 promoter. SLUG knockdown inhibited HK2 expression and weakened 4-OHT resistance of MDA-MB-231 cells. Conversely, SLUG overexpression elevated HK2 level and increased 4-OHT resistance of MCF7 cells. Combination of curcumin and 4-OHT suppressed SLUG and HK2 expression, leading to mitochondrion-mediated apoptosis. These results suggested SLUG as a potential target and curcumin as a promising natural agent for overcoming 4-OHT resistance of TNBC.

Sef Regulates Epithelial-Mesenchymal Transition in Breast Cancer Cells

Sef (similar expression to fgf), also know as IL17RD, is a transmembrane protein shown to inhibit fibroblast growth factor signaling in developmental and cancer contexts; however, its role as a tumor suppressor remains to be fully elucidated. Here, we show that Sef regulates epithelial-mesenchymal transition (EMT) in breast cancer cell lines. Sef expression was highest in the normal breast epithelial cell line MCF10A, intermediate expression in MCF-7 cells and lowest in MDA-MB-231 cells. Knockdown of Sef increased the expression of genes associated with EMT, and promoted cell migration, invasion, and a fibroblastic morphology of MCF-7 cells. Overexpression of Sef inhibited the expression of EMT marker genes and inhibited cell migration and invasion in MCF-7 cells. Induction of EMT in MCF10A cells by TGF-β and TNF-α resulted in downregulation of Sef expression concomitant with upregulation of EMT gene expression and loss of epithelial morphology. Overexpression of Sef in MCF10A cells partially blocked cytokine-induced EMT. Sef was shown to block β-catenin mediated luciferase reporter activity and to cause a decrease in the nuclear localization of active β-catenin. Furthermore, Sef was shown to co-immunoprecipitate with β-catenin. In a mouse orthotopic xenograft model, Sef overexpression in MDA-MB-231 cells slowed tumor growth and reduced expression of EMT marker genes. Together, these data indicate that Sef plays a role in the negative regulation of EMT in a β-catenin dependent manner and that reduced expression of Sef in breast tumor cells may be permissive for EMT and the acquisition of a more metastatic phenotype. J. Cell. Biochem. 117: 2346-2356, 2016. © 2016 Wiley Periodicals, Inc.

Fibrillin-1, induced by Aurora-A but inhibited by BRCA2, promotes ovarian cancer metastasis

While Aurora-A (Aur A) provokes, BRCA2 restrains primary tumorigenesis, the roles of Aur A and BRCA2 in cancer metastasis remains unclear. Here, we show that the metastatic promoting markers SLUG, FBN1, and MMP2, 9, 13 are either stimulated or suppressed by Aur A or BRCA2, but the metastatic suppressors E-cadherin, β-catenin, and p53 are either inhibited or promoted by Aur A or BRCA2, leading to enhanced or reduced cell migration and invasion. Further study suggests that FBN1 inhibits E-cadherin and β-catenin, but stimulates MMP2, 9, 13. Depletion of SLUG abrogates FBN1 and MMP9, but increases E-cadherin, while p53 decreases both SLUG and FBN1. Animal assays demonstrate that FBN1 promotes both ovarian tumorigenesis and metastasis. Clinically, overexpression of BRCA2 or Aur A in ovarian cancer tissues predicts good or poor overall and disease free survivals. High expression of SLUG or FBN1 indicates poor overall survivals, whereas high expression of FBN1 but not of SLUG predicts poor disease free survival. No significant associations between p53 expression and patient survivals were found. Overall, FBN1, acts at the downstream of Aur A and BRCA2, promotes ovarian cancer metastasis through the p53 and SLUG-associated signaling, which may be useful for ovarian cancer diagnosis and treatment.

Targeting SLUG sensitizes leukemia cells to ADR-induced apoptosis

BACKGROUND AND AIMS

Slug is an E-cadherin repressor and a suppressor of PUMA (p53 upregulated modulator of apoptosis) and it has recently been demonstrated that Slug plays an important role in controlling apoptosis. In this study, we examined whether Slug's ability to silence expression suppresses the growth of leukemia HL-60 cells and/or sensitizes leukemia HL-60 cells to adriamycin (ADR) through induction of apoptosis.

METHODS

SLUG siRNA was transfected into the HL-60 and HL-60(ADR) cell lines (an adriamycin resistant cell line). The stably SLUG siRNA transfected HL-60 and HL-60(ADR) cells was transiently transfected with PUMA siRNA. The mRNA and protein expression of SLUG and PUMA were determined by Quantitative real-time RT-PCR and Western blot assay. The effects of SLUG siRNA alone or combined with ADR or PUMA siRNA on growth and apoptosis in HL-60 and HL-60(ADR) cells was detected by MTT, ELISA and terminal deoxynucleotidyl transferase-mediated nick end labeling (TUNEL) assay.

RESULTS

The results showed that SLUG was less expressed in the HL-60 cells, and high expressed in the HL-60(ADR) cells. Obvious down-regulation of SLUG mRNA and protein levels and up-regulation of PUMA mRNA and protein levels after SLUG siRNA transfection was showed in the HL-60(ADR) cells. Treatment with ADR induced SLUG mRNA and protein in the HL-60 cells. Significant positive correlation was observed between basal SLUG mRNA and protein and ADR sensitivity. SLUG gene silencing by SLUG siRNA transfection inhibited growth and induced apoptosis, and increased ADR killing of the HL-60 and HL-60(ADR) cell lines. After the SLUG siRNA transfected HL-60 and HL-60(ADR) cells was transiently transfected with PUMA siRNA, did not increase ADR killing of the HL-60 and HL-60(ADR) cell lines.

CONCLUSION

SLUG level positively correlated with sensitivity to ADR. SLUG siRNA could effectively reduce SLUG expression and induce PUMA expression and restore the drug sensitivity of resistant leukemic cells to conventional chemotherapeutic agents.