Phosphorylation of serine 68 of Twist1 by MAPKs stabilizes Twist1 protein and promotes breast cancer cell invasiveness

The effects of CypA on apoptosis: potential target for the treatment of diseases

Cyclophilin A (CypA), the first member of cyclophilins, is distributed extensively in eukaryotic and prokaryotic cells, primarily localized in the cytoplasm. In addition to acting as an intracellular receptor for cyclosporin A (CSA), CypA plays a crucial role in diseases such as aging and tumorigenesis. Apoptosis, a form of programmed cell death, is able to balance the rate of cell viability and death. In this review, we focus on the effects of CypA on apoptosis and the relationship between specific mechanisms of CypA promoting or inhibiting apoptosis and diseases, including tumorigenesis, cardiovascular diseases, organ injury, and microbial infections. Notably, the process of CypA promoting or inhibiting apoptosis is closely related to disease development. Finally, future prospects for the association of CypA and apoptosis are discussed, and a comprehensive understanding of the effects of CypA on apoptosis in relation to diseases is expected to provide new insights into the design of CypA as a therapeutic target for diseases. KEY POINTS: • Understand the effect of CypA on apoptosis. • CypA affects apoptosis through specific pathways. • The effect of CypA on apoptosis is associated with a variety of disease processes.

Mechanistic insights into Yifei Sanjie pill's regulation of EMT to enhance gefitinib treatment effect in NSCLC by in silico analysis and experimental validation

ETHNOPHARMACOLOGICAL RELEVANCE

The Yi-Fei San-Jie pill (YFSJ) is a well-known Chinese medicine that has been used to treat non-small cell lung cancer in China for decades.

AIM OF THE STUDY

Previous studies have shown that YFSJ combined with gefitinib can effectively inhibit the proliferation of gefitinib-resistant non-small cell lung cancer (NSCLC) cell lines by promoting apoptosis and autophagy, but the molecular biological mechanisms involved and whether YFSJ combined with gefitinib can have synergistic effects still need to be further explored. Thus, the present study aimed to establish an in silico and experimental framework to decipher the underlying mechanism by which YFSJ augments the efficacy of gefitinib in treating NSCLC.

MATERIALS AND METHODS

Integrated approaches, including microarray analysis, network pharmacology, RNA sequencing, bioinformatics algorithm analysis and in vivo and in vitro experiments, were applied to elucidate the underlying mechanism.

RESULTS

Analysis of microarray datasets indicated that gefitinib may play a role in the regulation of the epithelial-mesenchymal transition (EMT) of PC9 cells. EMT-related Gene Ontology (GO) terms and the MAPK pathway were found to be enriched in the differentially expressed genes (DEGs), and a decreasing trend was observed in the EMT score. Network pharmacology analysis revealed that the potential NSCLC-related targets of YFSJ also showed enrichment in EMT-related GO terms and the MAPK pathway. Experimental findings demonstrated that combined YFSJ-treated serum and gefitinib treatment significantly inhibited PC9 cell migration and invasion. In addition, the combined treatment dramatically reduced the tumour volume in an animal model. The effectiveness of the combination treatment surpassed that of gefitinib alone in both cell and animal experiments. RNA sequencing analysis revealed significant enrichment of DEGs in EMT-related GO terms for the gefitinib treatment group, YFSJ treatment group, and combination treatment group compared to the control group. Notably, the negative regulation of EMT showed significant enrichment in the DEGs of the combination treatment group. The MAPK pathway was significantly enriched among the different groups. Moreover, combined treatment with YFSJ and gefitinib may exert synergistic anti-NSCLC effects by inhibiting the p-p38 MAPK/GSK3β signalling axis, subsequently suppressing downstream EMT processes.

CONCLUSION

Combined treatment with YFSJ and gefitinib could enhance the sensitivity of NSCLC cells to gefitinib by suppressing EMT through the EGFR/p-p38 MAPK/GSK3β signalling axis. YFSJ may serve as an important adjunctive medication for NSCLC patients receiving gefitinib treatment in clinical practice.

TWIST1 is a critical downstream target of the HGF/MET pathway and is required for MET driven acquired resistance in oncogene driven lung cancer

MET amplification/mutations are important targetable oncogenic drivers in NSCLC, however, acquired resistance is inevitable and the majority of patients with targetable MET alterations fail to respond to MET tyrosine kinase inhibitors (TKIs). Furthermore, MET amplification is among the most common mediators of TKI resistance. As such, novel therapies to target MET pathway and overcome MET TKI resistance are clearly needed. Here we show that the epithelial-mesenchymal transition (EMT) transcription factor, TWIST1 is a key downstream mediator of HGF/MET induced resistance through suppression of p27 and targeting TWIST1 can overcome resistance. We found that TWIST1 is overexpressed at the time of TKI resistance in multiple MET-dependent TKI acquired resistance PDX models. We have shown for the first time that MET directly stabilized the TWIST protein leading to TKI resistance and that TWIST1 was required for MET-driven lung tumorigenesis as well as could induce MET TKI resistance when overexpressed. TWIST1 mediated MET TKI resistance through suppression of p27 expression and genetic or pharmacologic inhibition of TWIST1 overcame TKI resistance in vitro and in vivo. Our findings suggest that targeting TWIST1 may be an effective therapeutic strategy to overcome resistance in MET-driven NSCLC as well as in other oncogene driven subtypes in which MET amplification is the resistance mechanism.

Exploiting transcription factors to target EMT and cancer stem cells for tumor modulation and therapy

Transcription factors (TFs) are essential in controlling gene regulatory networks that determine cellular fate during embryogenesis and tumor development. TFs are the major players in promoting cancer stemness by regulating the function of cancer stem cells (CSCs). Understanding how TFs interact with their downstream targets for determining cell fate during embryogenesis and tumor development is a critical area of research. CSCs are increasingly recognized for their significance in tumorigenesis and patient prognosis, as they play a significant role in cancer initiation, progression, metastasis, and treatment resistance. However, traditional therapies have limited effectiveness in eliminating this subset of cells, allowing CSCs to persist and potentially form secondary tumors. Recent studies have revealed that cancer cells and tumors with CSC-like features also exhibit genes related to the epithelial-to-mesenchymal transition (EMT). EMT-associated transcription factors (EMT-TFs) like TWIST and Snail/Slug can upregulate EMT-related genes and reprogram cancer cells into a stem-like phenotype. Importantly, the regulation of EMT-TFs, particularly through post-translational modifications (PTMs), plays a significant role in cancer metastasis and the acquisition of stem cell-like features. PTMs, including phosphorylation, ubiquitination, and SUMOylation, can alter the stability, localization, and activity of EMT-TFs, thereby modulating their ability to drive EMT and stemness properties in cancer cells. Although targeting EMT-TFs holds potential in tackling CSCs, current pharmacological approaches to do so directly are unavailable. Therefore, this review aims to explore the role of EMT- and CSC-TFs, their connection and impact in cellular development and cancer, emphasizing the potential of TF networks as targets for therapeutic intervention.

Crosstalk between lipid metabolism and EMT: emerging mechanisms and cancer therapy

Lipids are the key component of all membranes composed of a variety of molecules that transduce intracellular signaling and provide energy to the cells in the absence of nutrients. Alteration in lipid metabolism is a major factor for cancer heterogeneity and a newly identified cancer hallmark. Reprogramming of lipid metabolism affects the diverse cancer phenotypes, especially epithelial-mesenchymal transition (EMT). EMT activation is considered to be an essential step for tumor metastasis, which exhibits a crucial role in the biological processes including development, wound healing, and stem cell maintenance, and has been widely reported to contribute pathologically to cancer progression. Altered lipid metabolism triggers EMT and activates multiple EMT-associated oncogenic pathways. Although the role of lipid metabolism-induced EMT in tumorigenesis is an attractive field of research, there are still significant gaps in understanding the underlying mechanisms and the precise contributions of this interplay. Further study is needed to clarify the specific molecular mechanisms driving the crosstalk between lipid metabolism and EMT, as well as to determine the potential therapeutic implications. The increased dependency of tumor cells on lipid metabolism represents a novel therapeutic target, and targeting altered lipid metabolism holds promise as a strategy to suppress EMT and ultimately inhibit metastasis.

Harnessing function of EMT in cancer drug resistance: a metastasis regulator determines chemotherapy response

Epithelial-mesenchymal transition (EMT) is a complicated molecular process that governs cellular shape and function changes throughout tissue development and embryogenesis. In addition, EMT contributes to the development and spread of tumors. Expanding and degrading the surrounding microenvironment, cells undergoing EMT move away from the main location. On the basis of the expression of fibroblast-specific protein-1 (FSP1), fibroblast growth factor (FGF), collagen, and smooth muscle actin (-SMA), the mesenchymal phenotype exhibited in fibroblasts is crucial for promoting EMT. While EMT is not entirely reliant on its regulators like ZEB1/2, Twist, and Snail proteins, investigation of upstream signaling (like EGF, TGF-β, Wnt) is required to get a more thorough understanding of tumor EMT. Throughout numerous cancers, connections between tumor epithelial and fibroblast cells that influence tumor growth have been found. The significance of cellular crosstalk stems from the fact that these events affect therapeutic response and disease prognosis. This study examines how classical EMT signals emanating from various cancer cells interfere to tumor metastasis, treatment resistance, and tumor recurrence.

Determination of In Vitro and In Vivo Effects of Taxifolin and Epirubicin on Epithelial-Mesenchymal Transition in Mouse Breast Cancer Cells

Background: One of the most significant characteristics of cancer is epithelial-mesenchymal transition and research on the relationship between phenolic compounds and anticancer medications and epithelial-mesenchymal transition is widespread. Methods: In order to investigate the potential effects of Taxifolin on enhancing the effectiveness of Epirubicin in treating breast cancer, specifically in 4T1 cells and an allograft BALB/c model, the effects of Taxifolin and Epirubicin, both individually and in combination, were examined. Cell viability assays and cytotoxicity assays in 4T1 cells were performed. In addition, 4T1 cells were implanted into female BALB/c mice to conduct in vivo studies and evaluate the therapeutic efficacy of Taxifolin and Epirubicin alone or in combination. Tumor volumes and histological analysis were also assessed in mice. To further understand the mechanisms involved, we examined the messenger RNA and protein levels of epithelial-mesenchymal transition-related genes, as well as active Caspase-3/7 levels, using quantitative real-time polymerase chain reaction, western blot, and enzyme-linked immunosorbent assays, respectively. Results: In vitro results demonstrated that the coadministration of Taxifolin and Epirubicin reduced cell viability and cytotoxicity in 4T1 cell lines. In vivo, coadministration of Taxifolin and Epirubicin suppressed tumor growth in BALB/c mice with 4T1 breast cancer cells. Additionally, this combination treatment significantly increased the levels of active caspase-3/7 and downregulated the messenger RNA and protein levels of N-cadherin, β-catenin, vimentin, snail, and slug, but upregulated the E-cadherin gene. It significantly decreased the messenger RNA levels of the Zeb1 and Zeb2 genes. Conclusion: The in vitro and in vivo results of our study indicate that the concurrent use of Epirubicin with Taxifolin has supportive effects on breast cancer treatment.

FBXO3 stabilizes USP4 and Twist1 to promote PI3K-mediated breast cancer metastasis

Tumor metastasis is the major cause of breast cancer morbidity and mortality. It has been reported that the F-box protein FBXO3 functions as an E3 ubiquitin ligase in regulating various biological processes, including host autoimmune, antiviral innate immunity, and inflammatory response. However, the role of FBXO3 in tumor metastasis remains elusive. We have previously shown that ΔNp63α is a common inhibitory target in oncogene-induced cell motility and tumor metastasis. In this study, we show that FBXO3 plays a vital role in PI3K-mediated breast cancer metastasis independent of its E3 ligase activity and ΔNp63α in breast cancer cells and in mouse. FBXO3 can bind to and stabilize USP4, leading to Twist1 protein stabilization and increased breast cancer cell migration and tumor metastasis. Mechanistically, FBXO3 disrupts the interaction between USP4 and aspartyl aminopeptidase (DNPEP), thereby protecting USP4 from DNPEP-mediated degradation. Furthermore, p110αH1047R facilitates the phosphorylation and stabilization of FBXO3 in an ERK1-dependent manner. Knockdown of either FBXO3 or USP4 leads to significant inhibition of PI3K-induced breast cancer metastasis. Clinically, elevated expression of p110α/FBXO3/USP4/Twist1 is associated with poor overall survival (OS) and recurrence-free survival (RFS) of breast cancer patients. Taken together, this study reveals that the FBXO3-USP4-Twist1 axis is pivotal in PI3K-mediated breast tumor metastasis and that FBXO3/USP4 may be potential therapeutic targets for breast cancer treatment.

Molecular mechanisms of TWIST1-regulated transcription in EMT and cancer metastasis

TWIST1 induces epithelial-to-mesenchymal transition (EMT) to drive cancer metastasis. It is yet unclear what determines TWIST1 functions to activate or repress transcription. We found that the TWIST1 N-terminus antagonizes TWIST1-regulated gene expression, cancer growth and metastasis. TWIST1 interacts with both the NuRD complex and the NuA4/TIP60 complex (TIP60-Com) via its N-terminus. Non-acetylated TWIST1-K73/76 selectively interacts with and recruits NuRD to repress epithelial target gene transcription. Diacetylated TWIST1-acK73/76 binds BRD8, a component of TIP60-Com that also binds histone H4-acK5/8, to recruit TIP60-Com to activate mesenchymal target genes and MYC. Knockdown of BRD8 abolishes TWIST1 and TIP60-Com interaction and TIP60-Com recruitment to TWIST1-activated genes, resulting in decreasing TWIST1-activated target gene expression and cancer metastasis. Both TWIST1/NuRD and TWIST1/TIP60-Com complexes are required for TWIST1 to promote EMT, proliferation, and metastasis at full capacity. Therefore, the diacetylation status of TWIST1-K73/76 dictates whether TWIST1 interacts either with NuRD to repress epithelial genes, or with TIP60-Com to activate mesenchymal genes and MYC. Since BRD8 is essential for TWIST1-acK73/76 and TIP60-Com interaction, targeting BRD8 could be a means to inhibit TWIST1-activated gene expression.

An overview of Twist1 in glioma progression and recurrence

Glioma cells are characterized by high migration ability, resulting in the aggressive growth of the tumors and poor prognosis of patients. Epithelial-to-mesenchymal transition (EMT) is one of the most important steps for tumor migration and metastasis and be elevated during glioma progression and recurrence. Twist1 is a basic helix-loop-helix transcription factor and a key transcription factor involved in the process of EMT. Twist1 is related to glioma mesenchymal change, invasion, heterogeneity, self-renewal of tumor stem cells, angiogenesis, etc., and may be used as a prognostic indicator and therapeutic target for glioma patients. This paper mainly reviews the structural characteristics, regulatory mechanisms, and apparent regulation of Twist1, as well as the roles of Twist1 during glioma progression and recurrence, providing new revelations for its use as a potential drug target and glioma treatment research.

Reciprocal regulation of TWIST1 and OGT determines the decitabine efficacy in MDS/AML

Chemoresistance poses a significant impediment to effective treatment strategies for myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML). Our previous study unveiled that oncogene TWIST1 interacted with DNA methyltransferase 3a (DNMT3a) to regulate the decitabine (DAC) resistance in MDS/AML. However, the underlying mechanism of TWIST1 dysregulation in DAC resistance remained enigmatic. Here, we found that O-GlcNAc modification was upregulated in CD34+ cells from MDS/AML patients who do not respond to DAC treatment. Functional study revealed that O-GlcNAcylation could stabilize TWIST1 by impeding its interaction with ubiquitin E3 ligase CBLC. In addition, as one typical transcription factor, TWIST1 could bind to the promoter of O-GlcNAc transferase (OGT) gene and activate its transcription. Collectively, we highlighted the crucial role of the O-GlcNAcylated TWIST1 in the chemoresistance capacity of MDS/AML clonal cells, which may pave the way for the development of a new therapeutic strategy targeting O-GlcNAcylated proteins and reducing the ratio of MDS/AML relapse. Video Abstract.

Role of pelitinib in the regulation of migration and invasion of hepatocellular carcinoma cells via inhibition of Twist1

BACKGROUND

Overexpression of Twist1, one of the epithelial-mesenchymal transition-transcription factors (EMT-TFs), is associated with hepatocellular carcinoma (HCC) metastasis. Pelitinib is known to be an irreversible epidermal growth factor receptor tyrosine kinase inhibitor that is used in clinical trials for colorectal and lung cancers, but the role of pelitinib in cancer metastasis has not been studied. This study aimed to investigate the anti-migration and anti-invasion activities of pelitinib in HCC cell lines.

METHODS

Using three HCC cell lines (Huh7, Hep3B, and SNU449 cells), the effects of pelitinib on cell cytotoxicity, invasion, and migration were determined by cell viability, wound healing, transwell invasion, and spheroid invasion assays. The activities of MMP-2 and -9 were examined through gelatin zymography. Through immunoblotting analyses, the expression levels of EMT-TFs (Snail1, Twist1, and ZEB1) and EMT-related signaling pathways such as mitogen-activated protein kinases (MAPKs) and Akt signaling pathways were measured. The activity and expression levels of target genes were analyzed by reporter assay, RT-PCR, quantitative RT-PCR, and immunoblotting analysis. Statistical analysis was performed using one-way ANOVA with Dunnett's Multiple comparison tests in Prism 3.0 to assess differences between experimental conditions.

RESULTS

In this study, pelitinib treatment significantly inhibited wound closure in various HCC cell lines, including Huh7, Hep3B, and SNU449. Additionally, pelitinib was found to inhibit multicellular cancer spheroid invasion and metalloprotease activities in Huh7 cells. Further investigation revealed that pelitinib treatment inhibited the migration and invasion of Huh7 cells by inducing Twist1 degradation through the inhibition of MAPK and Akt signaling pathways. We also confirmed that the inhibition of cell motility by Twist1 siRNA was similar to that observed in pelitinib-treated group. Furthermore, pelitinib treatment regulated the expression of target genes associated with EMT, as demonstrated by the upregulation of E-cadherin and downregulation of N-cadherin.

CONCLUSION

Based on our novel finding of pelitinib from the perspective of EMT, pelitinib has the ability to inhibit EMT activity of HCC cells via inhibition of Twist1, and this may be the potential mechanism of pelitinib on the suppression of migration and invasion of HCC cells. Therefore, pelitinib could be developed as a potential anti-cancer drug for HCC.

Anti-migration and anti-invasion effects of LY-290181 on breast cancer cell lines through the inhibition of Twist1

Breast cancer has become the most common cancer among women worldwide. Among breast cancers, metastatic breast cancer is associated with the highest mortality rate. Twist1, one of the epithelial-mesenchymal transition-regulating transcription factors, is known to promote the intravasation of breast cancer cells into metastatic sites. Therefore, targeting Twist1 to develop anti-cancer drugs might be a valuable strategy. In this study, LY-290181 dose-dependently inhibited migration, invasion, and multicellular tumor spheroid invasion in breast cancer cell lines. These anti-cancer effects of LY-290181 were mediated through the down-regulation of Twist1 protein levels. LY-290181 inhibited extracellular signal-regulated kinase and c-Jun N-terminal kinase signaling pathways. Therefore, our findings suggest that LY-290181 may serve as a basis for future research and development of an anti-cancer agent targeting metastatic cancers. [BMB Reports 2023; 56(7): 410-415].

The ubiquitin-proteasome system in breast cancer

Ubiquitin-proteasome system (UPS) is a selective proteolytic system that is associated with the expression or function of target proteins and participates in various physiological and pathological processes of breast cancer. Inhibitors targeting the 26S proteasome in combination with other drugs have shown promising therapeutic effects in the clinical treatment of breast cancer. Moreover, several inhibitors/stimulators targeting other UPS components are also effective in preclinical studies, but have not yet been applied in the clinical treatment of breast cancer. Therefore, it is vital to comprehensively understand the functions of ubiquitination in breast cancer and to identify potential tumor promoters or tumor suppressors among UPS family members, with the aim of developing more effective and specific inhibitors/stimulators targeting specific components of this system.

Quercetin modulates signal transductions and targets non-coding RNAs against cancer development

In recent decades, various investigations have indicated that natural compounds have great potential in the prevention and treatment of different chronic disorders including different types of cancer. As a bioactive flavonoid, Quercetin (Qu) is a dietary ingredient enjoying high pharmacological values and health-promoting effects due to its antioxidant and anti-inflammatory characterization. Conclusive in vitro and in vivo evidence has revealed that Qu has great potential in cancer prevention and development. Qu exerts its anticancer influences by altering various cellular processes such as apoptosis, autophagy, angiogenesis, metastasis, cell cycle, and proliferation. In this way, Qu by targeting numerous signaling pathways as well as non-coding RNAs regulates several cellular mechanisms to suppress cancer occurrence and promotion. This review aimed to summarize the impact of Qu on the molecular pathways and non-coding RNAs in modulating various cancer-associated cellular mechanisms.

MAPKs in the early steps of senescence implemEMTation

Evidence is accumulating that the earliest stages of the DNA damage response can direct cells toward senescence instead of other cell fates. In particular, tightly regulated signaling through Mitogen-Activated Protein Kinases (MAPKs) in early senescence can lead to a sustained pro-survival program and suppress a pro-apoptotic program. Importantly, an epithelial-to-mesenchymal Transition (EMT)-like program appears essential for preventing apoptosis and favoring senescence following DNA damage. In this review, we discuss how MAPKs might influence EMT features to promote a senescent phenotype that increases cell survival at the detriment of tissue function.

Identification of potential crucial genes and mechanisms associated with metastasis of medulloblastoma based on gene expression profile

OBJECTIVES

Medulloblastoma is the most common malignant brain tumor in childhood. Although metastasis constitutes one of the poorest prognostic indicators in this disease, the mechanisms that drive metastasis have received less attention. The aim of our study is to provide valid biological information for the metastasis mechanism of medulloblastoma.

METHODS

Gene expression profile of GSE468 was downloaded from GEO database and was analyzed using limma R package. Function and enrichment analyses of DEGs were performed based on PANTHER database. PPI network construction, hub gene selection and module analysis were conducted in Cytoscape software.

RESULTS

Nine upregulated genes and 34 downregulated genes were selected as DEGs. The upregulated genes were mainly enriched in molecular function and cell component, which mainly included protein binding and nucleus respectively. A total of 120 enriched GO terms and 40 KEGG pathways were identified. The main enriched GO terms were the biological process such as apoptosis and MAPK activity. Besides, the enriched KEGG pathways also included MAPK signaling pathway. A PPI network was obtained, and JUN was identified as a hub gene. Also, we firstly investigated the role and regulatory mechanism of JUN in the metastasis of medulloblastoma.

CONCLUSIONS

Through the bioinformatics analysis of the gene microarray in GEO, we found some crucial genes and pathways associated with the metastasis of medulloblastoma.

The Transcription Factor Twist1 Has a Significant Role in Mycosis Fungoides (MF) Cell Biology: An RNA Sequencing Study of 40 MF Cases

The purpose of this RNA sequencing study was to investigate the biological mechanism underlying how the transcription factors (TFs) Twist1 and Zeb1 influence the prognosis of mycosis fungoides (MF). We used laser-captured microdissection to dissect malignant T-cells obtained from 40 skin biopsies from 40 MF patients with stage I-IV disease. Immunohistochemistry (IHC) was used to determinate the protein expression levels of Twist1 and Zeb1. Based on RNA sequencing, principal component analysis (PCA), differential expression (DE) analysis, ingenuity pathway analysis (IPA), and hub gene analysis were performed between the high and low Twist1 IHC expression cases. The DNA from 28 samples was used to analyze the TWIST1 promoter methylation level. In the PCA, Twist1 IHC expression seemed to classify cases into different groups. The DE analysis yielded 321 significant genes. In the IPA, 228 significant upstream regulators and 177 significant master regulators/causal networks were identified. In the hub gene analysis, 28 hub genes were found. The methylation level of TWIST1 promoter regions did not correlate with Twist1 protein expression. Zeb1 protein expression did not show any major correlation with global RNA expression in the PCA. Many of the observed genes and pathways associated with high Twist1 expression are known to be involved in immunoregulation, lymphocyte differentiation, and aggressive tumor biology. In conclusion, Twist1 might be an important regulator in the disease progression of MF.

USP13 promotes breast cancer metastasis through FBXL14-induced Twist1 ubiquitination

PURPOSE

Epithelial-to-mesenchymal transition (EMT) is an important cause of high mortality in breast cancer. Twist1 is one of the EMT transcription factors (EMT-TFs) with a noticeably short half-life, which is regulated by proteasome degradation pathways. Recent studies have found that USP13 stabilizes several specific oncogenic proteins. As yet, however, the relationship between Twist1 and USP13 has not been investigated.

METHODS

Co-Immunoprecipitation, GST-pulldown, Western blot, qRT-PCR and immunofluorescence assays were used to investigate the role of USP13 in de-ubiquitination of Twist1. Chromatin immunoprecipitation and Luciferase reporter assays were used to investigate the role of Twist1 in inhibiting USP13 reporter transcription. Scratch wound healing, cell migration and invasion assays, and a mouse lung metastases assay were used to investigate the roles of USP13 and Twist1 in promoting breast cancer metastasis.

RESULTS

We found that Twist1 can be de-ubiquitinated by USP13. In addition, we found that the protein levels of Twist1 dose-dependently increased with USP13 overexpression, while USP13 knockdown resulted in a decreased expression of endogenous Twist1. We also found that USP13 can directly interact with Twist1 and specifically cleave the K48-linked polyubiquitin chains of Twist1 induced by FBXL14. We found that the effect of USP13 in promoting the migration and invasion capacities of breast cancer cells can at least partly be achieved through its regulation of Twist1, while Twist1 can inhibit the transcriptional activity of USP13.

CONCLUSIONS

Our data indicate that an interplay between Twist1 and USP13 can form a negative physiological feedback loop. Our findings show that USP13 may play an essential role in breast cancer metastasis by regulating Twist1 and, as such, provide a potential target for the clinical treatment of breast cancer.

P4HA3 promotes clear cell renal cell carcinoma progression via the PI3K/AKT/GSK3β pathway

Clear cell renal cell carcinoma (ccRCC) is the most common subtype of renal cell carcinoma. P4HA3 is a key enzyme in collagen biosynthesis and has emerged as important molecules in regulation of proliferation, invasion, and metastasis in various tumor types. The role of P4HA3 in the development of ccRCC has remained to be elucidated. Genes expression, prognostic, and enrichment analyses were carried out with bioinformatics analysis. The efficiency of P4HA3 knockdown was confirmed by real-time quantitative PCR and Western blotting. The cellular functions were analyzed by CCK-8, EdU, wound healing, and transwell assays. The levels of related proteins expression were analyzed by Western blotting. P4HA3 was highly expressed in ccRCC compared with normal tissue samples from the TCGA database. Kaplan-Meier curves results showed that the expression level of P4HA3 was significantly negatively correlated with overall survival of patients. P4HA3 expression knockdown inhibited the proliferation, migration, and invasion of ccRCC cells, as demonstrated by in vitro experiments. In addition, GSEA results revealed that P4HA3 may be related to EMT and involved in the PI3K-AKT-GSK3β pathway in ccRCC; this was tentatively confirmed through Western blotting. P4HA3 may induce ccRCC progression via the PI3K-AKT-GSK3β signaling pathway and could represent a potential therapeutic target.

The speckle-type POZ protein (SPOP) inhibits breast cancer malignancy by destabilizing TWIST1

Epithelial-mesenchymal transition (EMT) inducing transcription factor TWIST1 plays a vital role in cancer metastasis. How the tumor-suppressive E3 ligase, speckle-type POZ protein (SPOP), regulates TWIST1 in breast cancer remains unknown. In this study, we report that SPOP physically interacts with, ubiquitinates, and destabilizes TWIST1. SPOP promotes K63-and K48-linked ubiquitination of TWIST1, predominantly at K73, thereby suppressing cancer cell migration and invasion. Silencing SPOP significantly enhances EMT, which accelerates breast cancer cell migration and invasiveness in vitro and lung metastasis in vivo. Clinically, SPOP is negatively correlated with the levels of TWIST1 in highly invasive breast carcinomas. Reduced SPOP expression, along with elevated TWIST1 levels, is associated with poor prognosis in advanced breast cancer patients, particularly those with metastatic triple-negative breast cancer (TNBC). Taken together, we have disclosed a new mechanism linking SPOP to TWIST1 degradation. Thus SPOP may serve as a prognostic marker and a potential therapeutic target for advanced TNBC patients.

Effects of thiostrepton alone or in combination with selumetinib on triple-negative breast cancer metastasis

OBJECTIVE

FoxM1 transcription factor contributes to tumor metastasis and poor prognosis in many cancers including triple-negative breast cancer (TNBC). In this study, we examined the effects of FoxM1 inhibitor Thiostrepton (THIO) alone or in combination with MEK inhibitor Selumetinib (SEL) on metastatic parameters in vitro and in vivo.

METHODS

Cell viability was determined by MTT assay. Immunoblotting and immunohistochemistry was used to assess metastasis-related protein expressions in 4T1 cells and its allograft tumor model in BALB/c mice. In vivo uPA activity was determined by enzymatic methods.

RESULTS

Both inhibitors were effective on the expressions of FoxM1, ERK, p-ERK, Twist, E-cadherin, and Vimentin alone or in combination in vitro. THIO significantly decreased 4T1 cell migration and changed the cell morphology from mesenchymal-like to epithelial-like structure. THIO was more effective than in combination with SEL in terms of metastatic protein expressions in vivo. THIO alone significantly inhibited mean tumor growth, decreased lung metastasis rate and tumor foci, however, no significant changes in these parameters were observed in the combined group. Immunohistochemically, FoxM1 expression intensity was decreased with THIO and its combination with SEL in the tumors.

CONCLUSIONS

This study suggests that inhibiting FoxM1 as a single target is more effective than combined treatment with MEK in theTNBC allograft model. The therapeutic efficacy of THIO should be investigated with further studies on appropriate drug delivery systems.

The molecular mechanisms and therapeutic strategies of EMT in tumor progression and metastasis

Epithelial–mesenchymal transition (EMT) is an essential process in normal embryonic development and tissue regeneration. However, aberrant reactivation of EMT is associated with malignant properties of tumor cells during cancer progression and metastasis, including promoted migration and invasiveness, increased tumor stemness, and enhanced resistance to chemotherapy and immunotherapy. EMT is tightly regulated by a complex network which is orchestrated with several intrinsic and extrinsic factors, including multiple transcription factors, post-translational control, epigenetic modifications, and noncoding RNA-mediated regulation. In this review, we described the molecular mechanisms, signaling pathways, and the stages of tumorigenesis involved in the EMT process and discussed the dynamic non-binary process of EMT and its role in tumor metastasis. Finally, we summarized the challenges of chemotherapy and immunotherapy in EMT and proposed strategies for tumor therapy targeting EMT.

Epithelial–Mesenchymal Transition by Synergy between Transforming Growth Factor-β and Growth Factors in Cancer Progression

Epithelial–mesenchymal transition (EMT) plays a crucial role in appropriate embryonic development, as well as wound healing, organ fibrosis, and cancer progression. During cancer progression, EMT is associated with the invasion, metastasis, and generation of circulating tumor cells and cancer stem cells, as well as resistance to chemo- and radiation therapy. EMT is induced by several transcription factors, known as EMT transcription factors (EMT-TFs). In nearly all cases, EMT-TFs appear to be regulated by growth factors or cytokines and extracellular matrix components. Among these factors, transforming growth factor (TGF)-β acts as the key mediator for EMT during physiological and pathological processes. TGF-β can initiate and maintain EMT by activating intracellular/intercellular signaling pathways and transcriptional factors. Recent studies have provided new insights into the molecular mechanisms underlying sustained EMT in aggressive cancer cells, EMT induced by TGF-β, and crosstalk between TGF-β and growth factors.

TWIST1 interacts with β/δ-catenins during neural tube development and regulates fate transition in cranial neural crest cells

Cell fate determination is a necessary and tightly regulated process for producing different cell types and structures during development. Cranial neural crest cells (CNCCs) are unique to vertebrate embryos and emerge from the neural plate borders into multiple cell lineages that differentiate into bone, cartilage, neurons and glial cells. We have previously reported that Irf6 genetically interacts with Twist1 during CNCC-derived tissue formation. Here, we have investigated the mechanistic role of Twist1 and Irf6 at early stages of craniofacial development. Our data indicate that TWIST1 is expressed in endocytic vesicles at the apical surface and interacts with β/δ-catenins during neural tube closure, and Irf6 is involved in defining neural fold borders by restricting AP2α expression. Twist1 suppresses Irf6 and other epithelial genes in CNCCs during the epithelial-to-mesenchymal transition (EMT) process and cell migration. Conversely, a loss of Twist1 leads to a sustained expression of epithelial and cell adhesion markers in migratory CNCCs. Disruption of TWIST1 phosphorylation in vivo leads to epidermal blebbing, edema, neural tube defects and CNCC-derived structural abnormalities. Altogether, this study describes a previously uncharacterized function of mammalian Twist1 and Irf6 in the neural tube and CNCCs, and provides new target genes for Twist1 that are involved in cytoskeletal remodeling.

TWIST1 methylation by SETD6 selectively antagonizes LINC-PINT expression in glioma

Gliomas are one of the most common and lethal brain tumors among adults. One process that contributes to glioma progression and recurrence is the epithelial to mesenchymal transition (EMT). EMT is regulated by a set of defined transcription factors which tightly regulate this process, among them is the basic helix-loop-helix family member, TWIST1. Here we show that TWIST1 is methylated on lysine-33 at chromatin by SETD6, a methyltransferase with expression levels correlating with poor survival in glioma patients. RNA-seq analysis in U251 glioma cells suggested that both SETD6 and TWIST1 regulate cell adhesion and migration processes. We further show that TWIST1 methylation attenuates the expression of the long-non-coding RNA, LINC-PINT, thereby promoting EMT in glioma. Mechanistically, TWIST1 methylation represses the transcription of LINC-PINT by increasing the occupancy of EZH2 and the catalysis of the repressive H3K27me3 mark at the LINC-PINT locus. Under un-methylated conditions, TWIST1 dissociates from the LINC-PINT locus, allowing the expression of LINC-PINT which leads to increased cell adhesion and decreased cell migration. Together, our findings unravel a new mechanistic dimension for selective expression of LINC-PINT mediated by TWIST1 methylation.

Tumor suppressor p53 restrains cancer cell dissemination by modulating mitochondrial dynamics

Tumor suppressor p53 plays a central role in preventing tumorigenesis. Here, we unravel how p53 modulates mitochondrial dynamics to restrain the metastatic properties of cancer cells. p53 inhibits the mammalian target of rapamycin complex 1 (mTORC1) signaling to attenuate the protein level of mitochondrial fission process 1 (MTFP1), which fosters the pro-fission dynamin-related protein 1 (Drp1) phosphorylation. This regulatory mechanism allows p53 to restrict cell migration and invasion governed by Drp1-mediated mitochondrial fission. Downregulating p53 expression or elevating the molecular signature of mitochondrial fission correlates with aggressive tumor phenotypes and poor prognosis in cancer patients. Upon p53 loss, exaggerated mitochondrial fragmentation stimulates the activation of the extracellular signal-regulated kinase 1/2 (ERK1/2) signaling resulting in epithelial-to-mesenchymal transition (EMT)-like changes in cell morphology, accompanied by accelerated matrix metalloproteinase 9 (MMP9) expression and invasive cell migration. Notably, blocking the activation of mTORC1/MTFP1/Drp1/ERK1/2 axis completely abolishes the p53 deficiency-driven cellular morphological switch, MMP9 expression, and cancer cell dissemination. Our findings unveil a hitherto unrecognized mitochondria-dependent molecular mechanism underlying the metastatic phenotypes of p53-compromised cancers.

Metastasis and MAPK Pathways

Cancer is a leading cause of death worldwide. In many cases, the treatment of the disease is limited due to the metastasis of cells to distant locations of the body through the blood and lymphatic drainage. Most of the anticancer therapeutic options focus mainly on the inhibition of tumor cell growth or the induction of cell death, and do not consider the molecular basis of metastasis. The aim of this work is to provide a comprehensive review focusing on cancer metastasis and the mitogen-activated protein kinase (MAPK) pathway (ERK/JNK/P38 signaling) as a crucial modulator of this process.

Transcriptional and post-transcriptional control of epithelial-mesenchymal plasticity: why so many regulators?

The dynamic transition between epithelial-like and mesenchymal-like cell states has been a focus for extensive investigation for decades, reflective of the importance of Epithelial-Mesenchymal Transition (EMT) through development, in the adult, and the contributing role EMT has to pathologies including metastasis and fibrosis. Not surprisingly, regulation of the complex genetic networks that underlie EMT have been attributed to multiple transcription factors and microRNAs. What is surprising, however, are the sheer number of different regulators (hundreds of transcription factors and microRNAs) for which critical roles have been described. This review seeks not to collate these studies, but to provide a perspective on the fundamental question of whether it is really feasible that so many regulators play important roles and if so, what does this tell us about EMT and more generally, the genetic machinery that controls complex biological processes.

A Mixture of Baicalein, Wogonin, and Oroxylin-A Inhibits EMT in the A549 Cell Line via the PI3K/AKT-TWIST1-Glycolysis Pathway

Non-small cell lung cancer (NSCLC) is a worldwide disease with a high morbidity and mortality rate, which is most derived from its metastasis. Some studies show that the epithelial–mesenchymal transition (EMT) process promotes lung cancer cell migration and invasion, leading to NSCLC metastasis. Total flavonoid aglycones extract (TFAE) isolated from Scutellaria baicalensis was reported to inhibit tumor growth and induce apoptosis. In this study, we found that baicalein, wogonin, and oroxylin-A were the active compounds of TFAE. After reconstructing with these three compounds [baicalein (65.8%), wogonin (21.2%), and oroxylin-A (13.0%)], the reconstructed TFAE (reTFAE) inhibited the EMT process of A549 cells. Then, bioinformatic technology was employed to elucidate the potential pharmacodynamic mechanism network of reTFAE. We identified the relationship between reTFAE and PI3K/Akt signaling pathways, with TWIST1 as the key protein. LY294002, the inhibitor of the PI3K/Akt signaling pathway, and knock-down TWIST1 could significantly enhance the efficacy of reTFAE, with increasing expression of epithelial markers and decreasing expression of mesenchymal markers in A549 cells at the same time. Furthermore, stable isotope dimethyl-labeled proteomics technology was conducted to complement the follow-up mechanism that the EMT-inhibition process may be realized through the glycolysis pathway. In conclusion, we claim that TWIST1-targeted flavonoids could provide a new strategy to inhibit EMT progress for the treatment of NSCLC.

Epithelial-to-Mesenchymal Transition Signaling Pathways Responsible for Breast Cancer Metastasis

Breast carcinoma is highly metastatic and invasive. Tumor metastasis is a convoluted and multistep process involving tumor cell disseminating from their primary site and migrating to the secondary organ. Epithelial-mesenchymal transition (EMT) is one of the crucial steps that initiate cell progression, invasion, and metastasis. During EMT, epithelial cells alter their molecular features and acquire a mesenchymal phenotype. The regulation of EMT is centered by several signaling pathways, including primary mediators TGF-β, Notch, Wnt, TNF-α, Hedgehog, and RTKs. It is also affected by hypoxia and microRNAs (miRNAs). All these pathways are the convergence on the transcriptional factors such as Snail, Slug, Twist, and ZEB1/2. In addition, a line of evidence suggested that EMT and cancer stem like cells (CSCs) are associated. EMT associated cancer stem cells display mesenchymal phenotypes and resist to chemotherapy or targeted therapy. In this review, we highlighted recent discoveries in these signaling pathways and their regulation in breast cancer metastasis and invasion. While the clinical relevance of EMT and breast cancers remains controversial, we speculated a convergent signaling network pivotal to elucidating the transition of epithelial to mesenchymal phenotypes and onset of metastasis of breast cancer cells.

Cyclophilin A regulates A549 cells apoptosis via stabilizing Twist1 protein

Cyclophilin A (CypA) is an essential member of the immunophilin family. As an intracellular target of immunosuppressive drug cyclosporin A (CsA) or a peptidyl-prolyl cis/trans isomerase (PPIase), it catalyzes the cis-trans isomerization of proline amidic peptide bonds, through which, it regulates a variety of biological processes, such as intracellular signaling, transcription, and apoptosis. In this study, we found that intracellular CypA enhanced Twist1 phosphorylation at Ser68 and inhibited apoptosis in A549 cells. Mechanistically, CypA could mediate the phosphorylation of Twist1 at Ser68 via p38 MAPK, which inhibited its ubiquitination-mediated degradation. In addition, CypA increased Twist-p65 interaction and nuclear accumulation, which regulated Twist1-dependent expression of CDH1 and CDH2. Our findings collectively indicated the role of CypA in Twist1-mediated A549 cells apoptosis through stabilizing Twist1 protein.

Understanding the Complex Milieu of Epithelial-Mesenchymal Transition in Cancer Metastasis: New Insight Into the Roles of Transcription Factors

Epithelial-mesenchymal transition (EMT) is a physiological program during which polarised, immobile epithelial cells lose connection with their neighbours and are converted to migratory mesenchymal phenotype. Mechanistically, EMT occurs via a series of genetic and cellular events leading to the repression of epithelial-associated markers and upregulation of mesenchymal-associated markers. EMT is very crucial for many biological processes such as embryogenesis and ontogenesis during human development, and again it plays a significant role in wound healing during a programmed replacement of the damaged tissues. However, this process is often hijacked in pathological conditions such as tumour metastasis, which constitutes the most significant drawback in the fight against cancer, accounting for about 90% of cancer-associated mortality globally. Worse still, metastatic tumours are not only challenging to treat with the available conventional radiotherapy and surgical interventions but also resistant to several cytotoxic agents during treatment, owing to their anatomically diffuse localisation in the body system. As the quest to find an effective method of addressing metastasis in cancer intervention heightens, understanding the molecular interplay involving the signalling pathways, downstream effectors, and their interactions with the EMT would be an important requisite while the challenges of metastasis continue to punctuate. Unfortunately, the molecular underpinnings that govern this process remain to be completely illuminated. However, it is becoming increasingly clear that EMT, which initiates every episode of metastasis, significantly requires some master regulators called EMT transcription factors (EMT-TFs). Thus, this review critically examines the roles of TFs as drivers of molecular rewiring that lead to tumour initiation, progression, EMT, metastasis, and colonisation. In addition, it discusses the interaction of various signalling molecules and effector proteins with these factors. It also provides insight into promising therapeutic targets that may inhibit the metastatic process to overcome the limitation of “undruggable” cancer targets in therapeutic design and upturn the current spate of drug resistance. More so, it extends the discussion from the basic understanding of the EMT binary switch model, and ultimately unveiling the E/M cellular plasticity along a phenotypic spectrum via multiple trans-differentiations. It wraps up on how this knowledge update shapes the diagnostic and clinical approaches that may demand a potential shift in investigative paradigm using novel technologies such as single-cell analyses to improve overall patient survival.

Tumor Microenvironment: Involved Factors and Signaling Pathways in Epithelial-Mesenchymal Transition

Context: Metastasis is a main cause of death in patients with cancer, whereby tumor cells withdraw from the primary site of the tumor mass and produce secondary tumor mass in new sites. Primary tumor cells depart collectively and individually to invade closed and distant sites. Evidence Acquisition: This review considers TME-derived factors that actuate signaling pathways to induce epithelial-mesenchymal transition (EMT). National Center for Biotechnology Information (NCBI) was the main resource. Google Scholar and Scopus were other databases for finding articles. Keywords that were inserted into the search box of databases to identify related articles were ‘metastasis’, ‘invasion’, ‘epithelial-mesenchymal transition’, ‘EMT’, ‘tumor microenvironment’, ‘TME’, ‘TME cells’, and ‘signaling pathway in EMT’. Titles and abstracts of the articles were studied to choose the right articles. Finally, 107 articles were selected to study in detail and use as references. Results: EMT is a type of metastasis that deprives epithelial single-cells of their characteristic features and acquires mesenchymal features facilitating the departure from the primary tumor mass. During EMT, cell-adhesion and apical-basal polarity rapture and cells obtain movement capability. The tumor microenvironment (TME) leads EMT through secretion factors and signaling pathways. As a result of activating these pathways, transcription factors that abolish epithelial gene expressions and augment mesenchymal gene expression are induced. Conclusions: In this review, recent research published in TME and EMT fields were highlighted and critically appraised. Effect of factors-derived TME cells on EMT were manifested that propose favorite targets for a therapeutic goal to inhibit metastasis. However, data about the effect of the combination of TME cells on metastasis have a small part in the literature.

Epithelial Mesenchymal Transition and Immune Response in Metaplastic Breast Carcinoma

Metaplastic breast carcinoma (MBC) is a heterogeneous group of infrequent triple negative (TN) invasive carcinomas with poor prognosis. MBCs have a different clinical behavior from other types of triple negative breast cancer (TNBC), being more resistant to standard chemotherapy. MBCs are an example of tumors with activation of epithelial–mesenchymal transition (EMT). The mechanisms involved in EMT could be responsible for the increase in the infiltrative and metastatic capacity of MBCs and resistance to treatments. In addition, a relationship between EMT and the immune response has been seen in these tumors. In this sense, MBC differ from other TN tumors showing a lower number of tumor-infiltrating lymphocytes (TILS) and a higher percentage of tumor cells expressing programmed death-ligand 1 (PD-L1). A better understanding of the relationship between the immune system and EMT could provide new therapeutic approaches in MBC.

The Tumor Suppressor Role of the Ras Association Domain Family 10

The Ras association domain family 10(RASSF10), a tumor suppressor gene, is located on human chromosome 11p15.2, which is one of the members homologous to other N-terminal RASSF families obtained through structural prediction. RASSF10 plays an important role in inhibiting proliferation, invasion, and migration, inducing apoptosis, making cancer cells sensitive to docetaxel, and capturing G2/M phase. Some studies have found that RASSF10 may inhibit the occurrence and development of tumors by regulating Wnt/β-catenin, P53, and MMP2. Methylation of tumor suppressor gene promoter is a key factor in the development and progression of many tumors. Various methylation detection methods confirmed that the methylation and downregulation of RASSF10 often occur in various tumors, such as gastric cancer, lung cancer, colon cancer, breast cancer, and leukemia. The status of RASSF10 methylation is positively correlated with tumor size, tumor type, and TNM stage. RASSF10 methylation can be used as a prognostic factor for overall survival and disease-free survival, and is also a sign of tumor diagnosis and sensitivity to docetaxel chemotherapy. In this review, we mainly elucidate the acknowledged structure and progress in the verified functions of RASSF10 and the probably relevant signaling pathways.

Human-derived osteoblast-like cells and pericyte-like cells induce distinct metastatic phenotypes in primary breast cancer cells

Approximately 70% of advanced breast cancer patients will develop bone metastases, which accounts for ∼90% of cancer-related mortality. Breast cancer circulating tumor cells (CTCs) establish metastatic tumors in the bone after a close interaction with local bone marrow cells including pericytes and osteoblasts, both related to resident mesenchymal stem/stromal cells (BM-MSCs) progenitors. In vitro recapitulation of the critical cellular players of the bone microenvironment and infiltrating CTCs could provide new insights into their cross-talk during the metastatic cascade, helping in the development of novel therapeutic strategies. Human BM-MSCs were isolated and fractionated according to CD146 presence. CD146+ cells were utilized as pericyte-like cells (PLCs) given the high expression of the marker in perivascular cells, while CD146- cells were induced into an osteogenic phenotype generating osteoblast-like cells (OLCs). Transwell migration assays were performed to establish whether primary breast cancer cells (3384T) were attracted to OLC. Furthermore, proliferation of 3384T breast cancer cells was assessed in the presence of PLC- and OLC-derived conditioned media. Additionally, conditioned media cultures as well as transwell co-cultures of each OLCs and PLCs were performed with 3384T breast cancer cells for gene expression interrogation assessing their induced transcriptional changes with an emphasis on metastatic potential. PLC as well as their conditioned media increased motility and invasion potential of 3384T breast cancer cells, while OLC induced a dormant phenotype, downregulating invasiveness markers related with migration and proliferation. Altogether, these results indicate that PLC distinctively drive 3384T cancer cells to an invasive and migratory phenotype, while OLC induce a quiescence state, thus recapitulating the different phases of the in vivo bone metastatic process. These data show that phenotypic responses from metastasizing cancer cells are influenced by neighboring cells at the bone metastatic niche during the establishment of secondary metastatic tumors.

The Post-Translational Regulation of Epithelial-Mesenchymal Transition-Inducing Transcription Factors in Cancer Metastasis

Epithelial-mesenchymal transition (EMT) is generally observed in normal embryogenesis and wound healing. However, this process can occur in cancer cells and lead to metastasis. The contribution of EMT in both development and pathology has been studied widely. This transition requires the up- and down-regulation of specific proteins, both of which are regulated by EMT-inducing transcription factors (EMT-TFs), mainly represented by the families of Snail, Twist, and ZEB proteins. This review highlights the roles of key EMT-TFs and their post-translational regulation in cancer metastasis.

Metastatic suppression by DOC2B is mediated by inhibition of epithelial-mesenchymal transition and induction of senescence

Senescence induction and epithelial-mesenchymal transition (EMT) events are the opposite sides of the spectrum of cancer phenotypes. The key molecules involved in these processes may get influenced or altered by genetic and epigenetic changes during tumor progression. Double C2-like domain beta (DOC2B), an intracellular vesicle trafficking protein of the double C2 protein family, plays a critical role in exocytosis, neurotransmitter release, and intracellular vesicle trafficking. DOC2B is repressed by DNA promoter hypermethylation and functions as a tumor growth regulator in cervical cancer. To date, the molecular mechanisms of DOC2B in cervical cancer progression and metastasis is elusive. Herein, the biological functions and molecular mechanisms regulated by DOC2B and its impact on senescence and EMT are described. DOC2B inhibition promotes proliferation, growth, and migration by relieving G0/G1-S arrest, actin remodeling, and anoikis resistance in Cal27 cells. It enhanced tumor growth and liver metastasis in nude mice with the concomitant increase in metastasis-associated CD55 and CD61 expression. Inhibition of EMT and promotion of senescence by DOC2B is a calcium-dependent process and accompanied by calcium-mediated interaction between DOC2B and CDH1. In addition, we have identified several EMT and senescence regulators as targets of DOC2B. We show that DOC2B may act as a metastatic suppressor by inhibiting EMT through induction of senescence via DOC2B-calcium-EMT-senescence axis.

The Effects of Quercetin on the Apoptosis of Human Breast Cancer Cell Lines MCF-7 and MDA-MB-231: A Systematic Review

This systematic review was performed with a focus on the effects of quercetin (QT) on the human breast cancer cell lines MCF-7 and MDA-MB-231. PubMed, Scopus, Science Direct, and Google Scholar databases were searched up to May 2020 using relevant keywords. All articles written in English evaluating the effects of QT on the human breast cancer cell lines MCF-7 and/or MDA-MB-231 were eligible for the review. Totally, 31 articles were included in this review. Out of them, 23 studies investigated the effects of QT on MCF-7 cells and indicated that QT induces apoptosis in the cells. Of 15 studies that examined the effects of QT on MDA-MB-231 cells, 14 reports showed successful apoptosis. It is concluded that QT might be beneficial in the eliminating of breast cancer cells. However, further clinical trials are warranted to further verify these outcomes.

Anti-Cancer Effects of Glaucarubinone in the Hepatocellular Carcinoma Cell Line Huh7 via Regulation of the Epithelial-To-Mesenchymal Transition-Associated Transcription Factor Twist1

Hepatocellular carcinoma (HCC), the most common type of liver cancer, is a leading cause of cancer-related deaths. As HCC has a high mortality rate and its incidence is increasing worldwide, understanding and treating HCC are crucial for resolving major public health concerns. In the present study, wound healing screening assays were performed using natural product libraries to identify natural chemicals that can inhibit cancer cell migration. Glaucarubinone (GCB) showed a high potential for inhibiting cell migration. The anti-cancer effects of GCB were evaluated using the HCC cell line, Huh7. GCB showed anti-cancer effects, as verified by wound healing, cell migration, invasion, colony formation, and three-dimensional spheroid invasion assays. In addition, cells treated with GCB showed suppressed matrix metalloproteinase activities. Immunoblotting analyses of intracellular signaling pathways revealed that GCB regulated the levels of Twist1, a crucial transcription factor associated with epithelial-to-mesenchymal transition, and mitogen-activated protein kinase. The invasive ability of cancer cells was found to be decreased by the regulation of Twist1 protein levels. Furthermore, GCB downregulated phosphorylation of extracellular signal-regulated kinase. These results indicate that GCB exhibits anti-metastatic properties in Huh7 cells, suggesting that it could be used to treat HCC.

MYB Proto-oncogene-like 1-TWIST1 Axis Promotes Growth and Metastasis of Hepatocellular Carcinoma Cells

MYB proto-oncogene-like 1 (MYBL1) has been reported to be a strong activator of transcription and plays an important role in the development of cancer. However, the precise biological function and molecular mechanism of MYBL1 in hepatocellular carcinoma (HCC) cells remain unclear. In the present study, we found that the expression of MYBL1 was markedly overexpressed in HCC cell lines and HCC samples, respectively. Moreover, MYBL1 expression positively correlated with tumor progression and inversely correlated with patient survival in 368 human HCC tissue samples. Overexpression of MYBL1 induced, whereas knockdown of MYBL1 reduced, HCC proliferation and metastasis both in vitro and in vivo. Furthermore, we demonstrated that HCC patients with high MYBL1 expression had significantly shorter overall and poorer disease-free survival than those with low MYBL1 expression. MYBL1 transcriptionally upregulated TWIST1 expression by directly targeting the TWIST1 promoter. More importantly, the in vitro analysis was consistent with the significant correlation between MYBL1 and TWIST1 expression observed in a large cohort of human HCC specimens. Taken together, our results demonstrate that MYBL1 plays an important role in HCC growth and metastasis and reveal a plausible mechanism for upregulation of TWIST1 in HCC.

Down-regulation of TRIB3 inhibits the progression of ovarian cancer via MEK/ERK signaling pathway

Background

Tribbles pseudokinase 3 (TRIB3) protein is a pseudokinase which plays an important role in cellular stress, metabolism, and tumor progression. However, the expression and function of TRIB3 in ovarian cancer is unknown.

Methods

TRIB3 expression was detected by immunohistochemistry in the ovarian tissue samples. Following down-regulation of TRIB3 by siRNA, multiple aspects of ovarian cancer cells were detected by the MTT assay, flow cytometry, scratch test and Transwell. Additionally, changes in related molecules and the MEK/ERK pathway were detected by western blotting. Finally, many bioinformatic methods, websites and databases, such as gene set enrichment analysis (GSEA), DVAID, Genemania, TISIDB and cBioPortal were used to study the TRIB3.

Results

The expression level of TRIB3 was higher in ovarian epithelial malignant tumors as compared to other groups. Patients with a high expression level of TRIB3 had significantly shorter survival times,which was consistent with the results of analysis of the KM-plot database. Down-regulation of TRIB3 expression significantly inhibited the proliferation, invasion, and migration capabilities of ovarian cancer cells, and induced apoptosis and cell cycle arrest. Following TRIB3 siRNA transfection, expression levels of relative proteins were found to be decreased. Additionally, analysis in DAVID website and GSEA revealed that TRIB3 expression was associated with multiple biological processes. Protein phosphorylation levels of MEK and ERK also decreased following TRIB3-siRNA transfection. The Genemania website was used to analyze the proteins that interact with TRIB3. Analysis of TRIB3 in the TISIDB database and cBioPortal website showed that ovarian cancer patients with high levels of mutation in TRIB3 had poor prognosis, and that the expression of TRIB3 was related to immunomodulation.

Conclusions

The TRIB3 was highly expressed and promoting the malignant behavior of ovarian cancer cells by activating the MEK-ERK signaling pathway. It was also found to be associated with genetic variations and immune modulators.

α-Linolenic acid inhibits the migration of human triple-negative breast cancer cells by attenuating Twist1 expression and suppressing Twist1-mediated epithelial-mesenchymal transition

α-Linolenic acid (ALA), an essential fatty acid, has anticancer activity in breast cancer, but the mechanism of its effects in triple-negative breast cancer (TNBC) remains unclear. We investigated the effect of ALA on Twist1, which is required to initiate epithelial-mesenchymal transition (EMT) and promotes tumor metastasis, and Twist1-mediated migration in MDA-MB231, MDA-MB468 and Hs578T cells. Twist1 protein was constitutively expressed in these TNBC cells, particularly MDA-MB-231 cells. Treatment with 100 μM ALA and Twist1 siRNA markedly decreased the Twist1 protein level and cell migration. Moreover, ALA transiently attenuated the nuclear accumulation of STAT3α as well as Twist1 mRNA expression. Treatment with ALA significantly attenuated the phosphorylation of JNK, ERK and Akt and decreased the phosphorylation of Twist1 at serine 68 in MDA-MB-231 cells. ALA accelerated Twist1 degradation in the presence of cycloheximide, whereas the ubiquitination and degradation of Twist1 by ALA was suppressed by MG-132. Pretreatment with ALA mimicked Twist1 siRNA, increased the protein expression of epithelial markers such as E-cadherin, and decreased the protein expression of mesenchymal markers including Twist1, Snail2, N-cadherin, vimentin, and fibronectin. Our findings suggest that ALA can be used not only to abolish EMT but also to suppress Twist1-mediated migration in TNBC cells.

AKT drives sustained motility following MEK inhibition via promoting SNAIL and AXL in MDA-MB-231 LM2

The adaptive activation of alternative signaling pathways contributes to acquired resistance against targeted cancer therapies. Our previous research has shown that blocking Ras/ERK signaling promotes PI3K/AKT signaling in the lung metastatic derivative of MDA-MB-231 (LM2). Because AKT activation was required to drive sustained cell motility following MEK suppression, we extend our research to elucidate how activation of the PI3K/AKT signaling drives sustained motility following MEK inhibition. Reverse phase protein array (RPPA) revealed that SNAIL (SNAI1) was upregulated in U0126 (MEK inhibitor)-treated LM2 cells. Importantly, LM2 cells simultaneously treated with U0126 and PI3K inhibitor LY294002 exhibited reduced expression of SNAIL. Furthermore, depletion of SNAIL led to reduced cell motility in U0126-treated LM2 cells. In addition, we identified AXL as another downstream effector of AKT. These results suggest that SNAIL and AXL are key factors mediating sustained motility of LM2 cells following MEK suppression. Because AKT mediates motile behavior under MEK suppression, our results suggest that AKT and AXL may be targeted to overcome resistance against drugs targeting the Ras/ERK pathway.

An overview of mammalian p38 mitogen-activated protein kinases, central regulators of cell stress and receptor signaling

The p38 family is a highly evolutionarily conserved group of mitogen-activated protein kinases (MAPKs) that is involved in and helps co-ordinate cellular responses to nearly all stressful stimuli. This review provides a succinct summary of multiple aspects of the biology, role, and substrates of the mammalian family of p38 kinases. Since p38 activity is implicated in inflammatory and other diseases, we also discuss the clinical implications and pharmaceutical approaches to inhibit p38.

Inhibition of p90RSK activation sensitizes triple-negative breast cancer cells to cisplatin by inhibiting proliferation, migration and EMT

Cisplatin (Cis-DDP) is one of the most widely used anti-cancer drugs. It is applicable to many types of cancer, including lung, bladder, and breast cancer. However, its use is now limited because of drug resistance. p90 ribosomal S6 kinase (p90RSK) is one of the downstream effectors in the extracellular signal-regulated protein kinases 1 and 2 (ERK1/2) pathway and high expression of p90RSK is observed in human breast cancer tissues. Therefore, we investigated the role of p90RSK in the Cis-DDP resistance-related signaling pathway and epithelial-mesenchymal transition (EMT) in breast cancer cells. First, we discovered that MDA-MB-231 cells exhibited more Cis-DDP resistance than other breast cancer cells, including MCF-7 and BT549 cells. Cis-DDP increased p90RSK activation, whereas the inactivation of p90RSK using a small interfering RNA (siRNA) or dominant-negative kinase mutant plasmid overexpression significantly reduced Cis-DDP-induced cell proliferation and migration via the inhibition of matrix metallopeptidase (MMP)2 and MMP9 in MDA-MB-231 cells. In addition, p90RSK activation was involved in EMT via the upregulation of mRNA expression, including that of Snail, Twist, ZEB1, N-cadherin, and vimentin. We also investigated NF-κB, the upstream regulator of EMT markers, and discovered that Cis-DDP treatment led to NF-κB translocation in the nucleus as well as its promoter activity. Our results suggest that targeting p90RSK would be a good strategy to increase Cis-DDP sensitivity in triple-negative breast cancers.

MicroRNA-761 suppresses remodeling of nasal mucosa and epithelial-mesenchymal transition in mice with chronic rhinosinusitis through LCN2

Background

Chronic rhinosinusitis (CRS) is characterized by persistent symptomatic inflammation of the nasal passage and sinus mucosa. Various microRNAs (miRs) have been implicated in CRS. Hence, the current study was conducted to explore the effect of microRNA-761 (miR-761) on remodeling of nasal mucosa and epithelial–mesenchymal transition (EMT).

Methods

Bioinformatics analysis was initially performed to predict the differentially expressed genes (DEGs) associated with CRS. Gene targeting relationship between miR-761 and lipocalin 2 (LCN2) was analyzed by bioinformatics analysis and verified using dual-luciferase reporter gene assay. Histopathological analyses of the nasal mucosa tissues were conducted via hematoxylin–eosin (HE) and alcian blue (AB)-periodic acid Schiff (PAS) staining. ELISA was employed to determine the IL-8 and MMP-9 levels. To define downstream pathway of miR-761, levels of proteins related to LCN2/Twist1 signaling pathway were assessed. Additionally, the effects of miR-761 on EMT, proliferation, and apoptosis were determined.

Results

LCN2 was highly expressed in CRS. LCN2 was a target of miR-761. miR-761 overexpression or LCN2 silencing decreased IL-8 and MMP-9 levels and morphological changes in nasal epithelial tissue from CRS mice. Overexpressed miR-761 or silenced LCN2 decreased the expression of LCN2 and Twist1, indicating LCN2/Twist1 signaling pathway was inactivated. Moreover, miR-761 overexpression or LCN2 silencing reduced the expression of N-cadherin and vimentin, while increased that of E-cadherin, suggesting inhibition of EMT. Furthermore, miR-761 overexpression or LCN2 silencing promoted cell proliferation and inhibited cell apoptosis in CRS.

Conclusion

Taken together, miR-761 suppressed the remodeling of nasal mucosa through inhibition of LCN2 and the LCN2/Twist1 signaling pathway.

Hypoxia-Induced Epithelial-Mesenchymal Transition in Cancers: HIF-1α and Beyond

Metastasis is the main cause of cancer-related mortality. Although the actual process of metastasis remains largely elusive, epithelial-mesenchymal transition (EMT) has been considered as a major event in metastasis. Besides, hypoxia is common in solid cancers and has been considered as an important factor for adverse treatment outcomes including metastasis. Since EMT and hypoxia potentially share several signaling pathways, many recent studies focused on investigate the issue of hypoxia-induced EMT. Among all potential mediators of hypoxia-induced EMT, hypoxia-inducible factor-1α (HIF-1α) has been studied extensively. Moreover, there are other potential mediators that may also contribute to the process. This review aims to summarize the recent reports on hypoxia-induced EMT by HIF-1α or other potential mediators and provide insights for further investigations on this issue. Ultimately, better understanding of hypoxia-induced EMT may allow us to develop anti-metastatic strategies and improve treatment outcomes.

Phosphoinositide-Dependent Signaling in Cancer: A Focus on Phospholipase C Isozymes

Phosphoinositides (PI) form just a minor portion of the total phospholipid content in cells but are significantly involved in cancer development and progression. In several cancer types, phosphatidylinositol 3,4,5-trisphosphate [PtdIns(3,4,5)P₃] and phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P₂] play significant roles in regulating survival, proliferation, invasion, and growth of cancer cells. Phosphoinositide-specific phospholipase C (PLC) catalyze the generation of the essential second messengers diacylglycerol (DAG) and inositol 1,4,5 trisphosphate (InsP₃) by hydrolyzing PtdIns(4,5)P₂. DAG and InsP₃ regulate Protein Kinase C (PKC) activation and the release of calcium ions (Ca²⁺) into the cytosol, respectively. This event leads to the control of several important biological processes implicated in cancer. PLCs have been extensively studied in cancer but their regulatory roles in the oncogenic process are not fully understood. This review aims to provide up-to-date knowledge on the involvement of PLCs in cancer. We focus specifically on PLCβ, PLCγ, PLCδ, and PLCε isoforms due to the numerous evidence of their involvement in various cancer types.