Epithelial–mesenchymal transitions in development and pathologies

Estrogen Receptors in Epithelial-Mesenchymal Transition of Prostate Cancer

Prostate cancer (PC) remains a widespread malignancy in men. Since the androgen/androgen receptor (AR) axis is associated with the pathogenesis of prostate cancer, suppression of AR-dependent signaling by androgen deprivation therapy (ADT) still represents the primary intervention for this disease. Despite the initial response, prostate cancer frequently develops resistance to ADT and progresses. As such, the disease becomes metastatic and few therapeutic options are available at this stage. Although the majority of studies are focused on the role of AR signaling, compelling evidence has shown that estrogens and their receptors control prostate cancer initiation and progression through a still debated mechanism. Epithelial versus mesenchymal transition (EMT) is involved in metastatic spread as well as drug-resistance of human cancers, and many studies on the role of this process in prostate cancer progression have been reported. We discuss here the findings on the role of estrogen/estrogen receptor (ER) axis in epithelial versus mesenchymal transition of prostate cancer cells. The pending questions concerning this issue are presented, together with the impact of the available data in clinical management of prostate cancer patients.

Epigallocatechin gallate (EGCG) suppresses epithelial-Mesenchymal transition (EMT) and invasion in anaplastic thyroid carcinoma cells through blocking of TGF-β1/Smad signaling pathways

Transforming growth factor (TGF)-β1 plays a crucial role in the epithelial-to-mesenchymal transition (EMT) in many cancer types and in thyroid cancers. Epigallocatechin-3-gallate (EGCG), the most important ingredient in the green tea, has been reported to possess antioxidant and anticancer activities. However, the cellular and molecular mechanisms explaining its action have not been completely understood. In this study, we found that EGCG significantly suppresses EMT, invasion and migration in anaplastic thyroid carcinoma (ATC) 8505C cells in vitro by regulating the TGF-β/Smad signaling pathways. EGCG significantly inhibited TGF-β1-induced expression of EMT markers (E-cadherin reduction and vimentin induction) in 8505C cells in vitro. Treatment with EGCG completely blocked the phosphorylation of Smad2/3, translocation of Smad4. Taken together, these results suggest that EGCG suppresses EMT and invasion and migration by blocking TGFβ/Smad signaling pathways.

Cdh4 Down-Regulation Impairs in Vivo Infiltration and Malignancy in Patients Derived Glioblastoma Cells

The high invasive phenotype of glioblastoma is one of the main causes of therapy inefficacy and tumor relapse. Cell adhesion molecules of the cadherin family are involved in cell migration and are known as master regulators of epithelial tumor invasiveness, but their role in glioblastoma is less understood. In particular, we recently demonstrated, in the syngeneic murine model, the occurrence of a previously undescribed cadherin switch between Cdh2 and Cdh4 during gliomagenesis, which is necessary for the acquisition of the highly infiltrative and tumorigenic phenotype of these cells. In the present study, we tested the role of Cdh4 in human gliomas. Our results on patient-derived glioma cells demonstrate a positive correlation between Cdh4 expression levels and the loss of cell-cell contact inhibition of proliferation controls that allows cells to proliferate over confluence. Moreover, the silencing of Cdh4 by artificial microRNAs induced a decrease in the infiltrative ability of human glioma cells both in vitro and in vivo. More strikingly, Cdh4 silencing induced an impairment of the tumorigenic potential of these cells after orthotopic transplantation in immunodeficient mice. Overall, we conclude that in human glioblastoma, Cdh4 can also actively contribute in regulating cell invasiveness and malignancy.

EFEMP2 suppresses epithelial-mesenchymal transition via Wnt/β-catenin signaling pathway in human bladder cancer

Epidermal growth factor-containing fibulin-like extracellular matrix protein 2 (EFEMP2), an extracellular matrix protein, is highly associated with tumor invasion and metastasis. However, influenced by the tumor microenvironment, EFEMP2 played different roles in different tumors. The current study focused on exploring the role of EFEMP2 in bladder cancer (BCa). The results suggested that the expression of EFEMP2 was significantly higher in normal tissues and cells compared with BCa samples and cells. And we found a negative correlation between EFEMP2 expression and high tumor stage, high tumor grade, patients with low EFEMP2 expression had a much poorer survival than those patients with high EFEMP2 expression. The multivariate analysis revealed that low EFEMP2 expression was a high-risk predictor of BCa survival. Furthermore, cell proliferation, migration and metastasis can be obviously affected by the changes of EFEMP2 expression both in vitro and in vivo. Our results also turned out that knockdown of EFEMP2 could significantly reduce the epithelial marker (E-cadherin), increase mesenchymal markers (N-cadherin, Vimentin, Snail and Slug) as well as the key factors of Wnt/β-catenin signaling pathway (β-catenin, c-Myc and cyclin D1). The reversed results were found in the EFEMP2 overexpression cells. Importantly, the related expression changes of epithelial-mesenchymal transition (EMT) markers and Wnt/β-catenin signaling pathway factors induced by EFEMP2 upregulation or downregulation can be rescued using LiCl or XAV939. Collectively, our observations revealed that EFEMP2 is a blocker of tumor progression and metastasis in BCa.

Microbial carcinogenesis: Lactic acid bacteria in gastric cancer

While Helicobacter pylori is a fundamental risk factor, gastric cancer (GC) aetiology involves combined effects of microbial (both H. pylori and non-H. pylori), host and environmental factors. Significant differences exist between the gastric microbiome of those with gastritis, intestinal metaplasia and GC, suggesting that dysbiosis in the stomach is dynamic and correlates with progression to GC. Most notably, a consistent increase in abundance of lactic acid bacteria (LAB) has been observed in GC patients including Streptococcus, Lactobacillus, Bifidobacterium and Lactococcus. This review summarises how LAB can influence GC by a number of mechanisms that include supply of exogenous lactate -a fuel source for cancer cells that promotes inflammation, angiogenesis, metastasis, epithelial-mesenchymal transition and immune evasion-, production of reactive oxygen species and N-nitroso compounds, as well as anti-H. pylori properties that enable colonization by other non-H. pylori carcinogenic pathobionts.

The Role of Cancer Stem Cells and Mechanical Forces in Ovarian Cancer Metastasis

Ovarian cancer is an extremely lethal gynecologic disease; with the high-grade serous subtype predominantly associated with poor survival rates. Lack of early diagnostic biomarkers and prevalence of post-treatment recurrence, present substantial challenges in treating ovarian cancers. These cancers are also characterized by a high degree of heterogeneity and protracted metastasis, further complicating treatment. Within the ovarian tumor microenvironment, cancer stem-like cells and mechanical stimuli are two underappreciated key elements that play a crucial role in facilitating these outcomes. In this review article, we highlight their roles in modulating ovarian cancer metastasis. Specifically, we outline the clinical relevance of cancer stem-like cells, and challenges associated with their identification and characterization and summarize the ways in which they modulate ovarian cancer metastasis. Further, we review the mechanical cues in the ovarian tumor microenvironment, including, tension, shear, compression and matrix stiffness, that influence (cancer stem-like cells and) metastasis in ovarian cancers. Lastly, we outline the challenges associated with probing these important modulators of ovarian cancer metastasis and provide suggestions for incorporating these cues in basic biology and translational research focused on metastasis. We conclude that future studies on ovarian cancer metastasis will benefit from the careful consideration of mechanical stimuli and cancer stem cells, ultimately allowing for the development of more effective therapies.

[Medium-chain acyl-CoA dehydrogenase enhances invasion and metastasis ability of breast cancer cells]

OBJECTIVE

To investigate the effect of medium-chain acyl-CoA dehydrogenase (ACADM) on invasion and metastasis of breast cancer cells and explore the underlying mechanism.

METHODS

A large cancer genome database was used to analyze the expression of ACADM in breast cancer tissues and normal tissues. The proliferation, migration and invasion of cultured breast cancer MCF-7 and T47D cells with ACADM overexpression or ACADM silencing were evaluated using MTT proliferation assay, EdU assay, Transwell chamber assay, and Boyden invasion assay; Western blotting was used to detect the protein expressions of the related pathway in the cells. In nude mouse models of tail vein metastasis of MCF-7 cells with or without ACADM overexpression, the tumor growth and tumor histopathology were observed using HE staining.

RESULTS

Analysis of the Oncomine sample set showed a significantly higher expression level of ACADM in breast cancer tissues than in normal breast tissues (P < 0.05). Overexpression of ACADM obviously enhanced the migration and invasion abilities and promoted the epithelial-mesenchymal transition (EMT) of cultured MCF-7 and T47D cells; conversely, silencing of ACADM significantly suppressed the migration and invasion of the breast cancer cells. In the nude mouse models, ACADM overexpression in MCF-7 cells significantly enhanced their in vivo migration and invasion abilities.

CONCLUSIONS

ACADM can promote the EMT process of breast cancer cells and improve the migration and invasion ability. ACADM is an oncogene in breast cancer.

Knockdown of XB130 restrains cancer stem cell-like phenotype through inhibition of Wnt/β-Catenin signaling in breast cancer

The cancer stem cells (CSCs) is a subset of cancer cells that possess stem cell properties, which plays a crucial role in the occurrence, metastasis, and recurrence of the tumor. XB130 is a novel adapter protein potentially serves as a functional factor in CSCs. To determine the role of CSCs in breast cancer, we focused on the study of XB130. In our study, we found that XB130 expression was significantly upregulated in breast cancer and was closely related to the clinicopathologic characteristics, overall survival and poor prognosis of breast cancer patients. Functionally, we found that knockdown of XB130 was not only played an important role in proliferation, epithelial-mesenchymal transition (EMT), and metastasis in breast cancer cells but also exhibited potent antitumor activity in animal tumor models. Moreover, we demonstrated that silencing endogenous XB130 regulated the cancer stem cell-like properties of breast cancer, including the formation of self-renewing spheres and the proportion of breast cancer SP⁺ cells. Mechanistically, our studies indicated that downregulation of XB130 restrained the EMT and Wnt/β-catenin signaling, so as to weaken the tumor-initiating cell-like phenotype of breast cancer cells. This study indicates that XB130 plays an important role in maintaining the EMT and stem cell-like characteristics of breast cancer cells, supporting the significance of XB130 as a new potential therapeutic target for early diagnosis and prognosis of breast cancer.

KIAA0101 is a novel transcriptional target of FoxM1 and is involved in the regulation of hepatocellular carcinoma microvascular invasion by regulating epithelial-mesenchymal transition

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-related deaths due to tumor invasiveness, frequent intrahepatic dissemination and extrahepatic metastasis. However, the genes and signaling pathways that are involved remain incompletely understood. In this study, weighted gene coexpression network analysis (WGCNA) was performed to jointly analyze clinical information and gene expression data to identify key genes associated with clinical features. Through the bioinformatic analysis, the yellow module and microvascular invasion (MVI) were found to be highly associated (r=0.41) by Pearson's correlation analysis, and 20 hub genes were identified with both high gene significance (GS) and high module membership (MM) in the yellow module. Among these genes, FoxM1 and KIAA0101 were upregulated in HCC with MVI and were significantly positively correlated in HCC samples, indicating a novel regulatory network in HCC microvascular invasion. Moreover, in vitro experiments demonstrated that KIAA0101 is a direct target of FoxM1 and that KIAA0101 is required for the FoxM1-induced promotion of HCC cell invasion and migration. In addition, the FoxM1-KIAA0101 axis promotes HCC metastasis by inducing epithelial-mesenchymal transition (EMT). In summary, KIAA0101 is a novel target of FoxM1 and contributes to HCC metastasis by activating EMT. The FoxM1-KIAA0101 axis might be applied as a potential prognostic biomarker and therapeutic target for HCC.

The matrix environmental and cell mechanical properties regulate cell migration and contribute to the invasive phenotype of cancer cells

The minimal structural unit of a solid tumor is a single cell or a cellular compartment such as the nucleus. A closer look inside the cells reveals that there are functional compartments or even structural domains determining the overall properties of a cell such as the mechanical phenotype. The mechanical interaction of these living cells leads to the complex organization such as compartments, tissues and organs of organisms including mammals. In contrast to passive non-living materials, living cells actively respond to the mechanical perturbations occurring in their microenvironment during diseases such as fibrosis and cancer. The transformation of single cancer cells in highly aggressive and hence malignant cancer cells during malignant cancer progression encompasses the basement membrane crossing, the invasion of connective tissue, the stroma microenvironments and transbarrier migration, which all require the immediate interaction of the aggressive and invasive cancer cells with the surrounding extracellular matrix environment including normal embedded neighboring cells. All these steps of the metastatic pathway seem to involve mechanical interactions between cancer cells and their microenvironment. The pathology of cancer due to a broad heterogeneity of cancer types is still not fully understood. Hence it is necessary to reveal the signaling pathways such as mechanotransduction pathways that seem to be commonly involved in the development and establishment of the metastatic and mechanical phenotype in several carcinoma cells. We still do not know whether there exist distinct metastatic genes regulating the progression of tumors. These metastatic genes may then be activated either during the progression of cancer by themselves on their migration path or in earlier stages of oncogenesis through activated oncogenes or inactivated tumor suppressor genes, both of which promote the metastatic phenotype. In more detail, the adhesion of cancer cells to their surrounding stroma induces the generation of intracellular contraction forces that deform their microenvironments by alignment of fibers. The amplitude of these forces can adapt to the mechanical properties of the microenvironment. Moreover, the adhesion strength of cancer cells seems to determine whether a cancer cell is able to migrate through connective tissue or across barriers such as the basement membrane or endothelial cell linings of blood or lymph vessels in order to metastasize. In turn, exposure of adherent cancer cells to physical forces, such as shear flow in vessels or compression forces around tumors, reinforces cell adhesion, regulates cell contractility and restructures the ordering of the local stroma matrix that leads subsequently to secretion of crosslinking proteins or matrix degrading enzymes. Hence invasive cancer cells alter the mechanical properties of their microenvironment. From a mechanobiological point-of-view, the recognized physical signals are transduced into biochemical signaling events that guide cellular responses such as cancer progression after the malignant transition of cancer cells from an epithelial and non-motile phenotype to a mesenchymal and motile (invasive) phenotype providing cellular motility. This transition can also be described as the physical attempt to relate this cancer cell transitional behavior to a T1 phase transition such as the jamming to unjamming transition. During the invasion of cancer cells, cell adaptation occurs to mechanical alterations of the local stroma, such as enhanced stroma upon fibrosis, and therefore we need to uncover underlying mechano-coupling and mechano-regulating functional processes that reinforce the invasion of cancer cells. Moreover, these mechanisms may also be responsible for the awakening of dormant residual cancer cells within the microenvironment. Physicists were initially tempted to consider the steps of the cancer metastasis cascade as single events caused by a single mechanical alteration of the overall properties of the cancer cell. However, this general and simple view has been challenged by the finding that several mechanical properties of cancer cells and their microenvironment influence each other and continuously contribute to tumor growth and cancer progression. In addition, basement membrane crossing, cell invasion and transbarrier migration during cancer progression is explained in physical terms by applying physical principles on living cells regardless of their complexity and individual differences of cancer types. As a novel approach, the impact of the individual microenvironment surrounding cancer cells is also included. Moreover, new theories and models are still needed to understand why certain cancers are malignant and aggressive, while others stay still benign. However, due to the broad variety of cancer types, there may be various pathways solely suitable for specific cancer types and distinct steps in the process of cancer progression. In this review, physical concepts and hypotheses of cancer initiation and progression including cancer cell basement membrane crossing, invasion and transbarrier migration are presented and discussed from a biophysical point-of-view. In addition, the crosstalk between cancer cells and a chronically altered microenvironment, such as fibrosis, is discussed including the basic physical concepts of fibrosis and the cellular responses to mechanical stress caused by the mechanically altered microenvironment. Here, is highlighted how biophysical approaches, both experimentally and theoretically, have an impact on classical hallmarks of cancer and fibrosis and how they contribute to the understanding of the regulation of cancer and its progression by sensing and responding to the physical environmental properties through mechanotransduction processes. Finally, this review discusses various physical models of cell migration such as blebbing, nuclear piston, protrusive force and unjamming transition migration modes and how they contribute to cancer progression. Moreover, these cellular migration modes are influenced by microenvironmental perturbances such as fibrosis that can induce mechanical alterations in cancer cells, which in turn may impact the environment. Hence, the classical hallmarks of cancer need to be refined by including biomechanical properties of cells, cell clusters and tissues and their microenvironment to understand mechano-regulatory processes within cancer cells and the entire organism.

Linkage between EMT and stemness state through molecular association between TWIST1 and NY-ESO1 in esophageal squamous cell carcinoma

Aberrant expression of cancer testis antigens (CTAs) is reported in tumors, especially those with stemness properties. A number of CTAs can induce epithelial mesenchymal transition (EMT) process and promote cancer stem cells (CSCs) characteristics. We aimed in this study to analyze the correlation between NY-ESO1 and TWIST1 in esophageal squamous cell carcinoma (ESCC), as well as their impact on EMT process. Gene expression profiling of NY-ESO1 and TWIST1 was performed in 43 esophageal tumors compared to their margin normal tissues of using qRT-PCR, and their correlation with clinicopathological variables of the patients was evaluated. In silico analysis of the NY-ESO1, epithelial and mesenchymal cell markers and also their promoter sequences was executed. ESCC cell lines KYSE-30 and YM-1 were transduced to ectopically express TWIST1 using a retroviral system, followed by qRT-PCR mRNA expression analysis to reveal the probable correlation among TWIST1, NY-ESO1 and EMT markers gene expression. Scratch assay was performed to estimate migration of TWIST1-induced cells. Overexpression of TWIST1 and NY-ESO1 mRNA was observed in 42% and 39.5% (P ˂ 0.05) of tumors, respectively. Expression of the genes was significantly correlated with each other (p = 0.005). TWIST1 and NY-ESO1 overexpression was significantly associated with stage of progression and size of tumors, respectively. A direct association between TWIST1 and NY-ESO1 mRNA expression was confirmed by induced ectopic expression of TWIST1 in ESCC cell lines KYSE-30 and YM-1. TWIST1-induced cells led to increase migration in ESCC cell line. Furthermore, significant up-regulation of EMT markers was observed following ectopic expression of TWIST1 in these cells. Based on our findings, it may be proposed that a vital association is exist between the EMT and the acquisition of cancer stemness state in tumor cells through the TWIST1/NY-ESO1 axis and it can be a critical hallmark in ESCC tumorigenesis.

Nuclear CD44 Mediated by Importin β Participated in Naïve Genes Transcriptional Regulation in C3A-iCSCs

CD44 is one of biomarkers of liver cancer stem cells (CSCs). The investigation of mechanism of CD44 translocation helps to uncover new molecular pathways participated in the regulation of various cellular processes in CSCs. In the present study, we observed the translocation of CD44 from cytoplasm to nuclear in the reprogramming process of C3A cells, full-length CD44 presented in the nucleus of liver iCSCs. CD44 was bound with importin β and transportin 1 in liver iCSCs. Inhibition of importin β transport leads to reduction of CD44 in the nucleus. Translocation of CD44 is also influenced by importin α. Besides, overexpression of naïve pluripotent genes, KLF2, KLF5, DNMT3L, GBX2, ZFP42, ESRRB and DPPA4 were found in liver iCSCs. Inhibition of CD44 leads to the reduction of these naïve genes. Luciferase and chromatin immunoprecipitation (ChIP) assays further identified nuclear CD44 bound to the promoter regions of naïve genes, KLF2, KLF5, and ESRRB functioned as transcriptional activators in liver iCSCs. Our present work provides new insight into the dynamic states and functions of CD44 in iCSCs.

A Ca2+-ATPase Regulates E-cadherin Biogenesis and Epithelial-Mesenchymal Transition in Breast Cancer Cells

Progression of benign tumors to invasive, metastatic cancer is accompanied by the epithelial-to-mesenchymal transition (EMT), characterized by loss of the cell-adhesion protein E-cadherin. Although silencing mutations and transcriptional repression of the E-cadherin gene have been widely studied, not much is known about posttranslational regulation of E-cadherin in tumors. We show that E-cadherin is tightly coexpressed with the secretory pathway Ca²⁺-ATPase isoform 2, SPCA2 (ATP2C2), in breast tumors. Loss of SPCA2 impairs surface expression of E-cadherin and elicits mesenchymal gene expression through disruption of cell adhesion in tumorspheres and downstream Hippo-YAP signaling. Conversely, ectopic expression of SPCA2 in triple-negative breast cancer elevates baseline Ca²⁺ and YAP phosphorylation, enhances posttranslational expression of E-cadherin, and suppresses mesenchymal gene expression. Thus, loss of SPCA2 phenocopies loss of E-cadherin in the Hippo signaling pathway and EMT-MET transitions, consistent with a functional role for SPCA2 in E-cadherin biogenesis. Furthermore, we show that SPCA2 suppresses invasive phenotypes, including cell migration in vitro and tumor metastasis in vivo. Based on these findings, we propose that SPCA2 functions as a key regulator of EMT and may be a potential therapeutic target for treatment of metastatic cancer. IMPLICATIONS: Posttranslational control of E-cadherin and the Hippo pathway by calcium signaling regulates EMT in breast cancer cells.

Potential Mechanisms of Action of Curcumin for Cancer Prevention: Focus on Cellular Signaling Pathways and miRNAs

Despite significant progressions in treatment modalities over the last decade, either cancer incidence or mortality is continuously on the rise throughout the world. Current anticancer agents display limited efficacy, accompanied by severe side effects. In order to improve therapeutic outcomes in patients with cancer, it is crucial to identify novel, highly efficacious pharmacological agents. Curcumin, a hydrophobic polyphenol extracted from turmeric, has gained increasing attention due to its powerful anticancer properties. Curcumin can inhibit the growth, invasion and metastasis of various cancers. The anticancer mechanisms of curcumin have been extensively studied. The anticancer effects of curcumin are mainly mediated through its regulation of multiple cellular signaling pathways, including Wnt/β-catenin, PI3K/Akt, JAK/STAT, MAPK, p53 and NF-ĸB signaling pathways. Moreover, curcumin also orchestrates the expression and activity of oncogenic and tumor-suppressive miRNAs. In this review, we summarized the regulation of these signaling pathways by curcumin in different cancers. We also discussed the modulatory function of curcumin in the downregulation of oncogenic miRNAs and the upregulation of tumor-suppressive miRNAs. An in-depth understanding of the anticancer mechanisms of curcumin will be helpful for developing this promising compound as a therapeutic agent in clinical management of cancer.

Glaucocalyxin A reverses EMT and TGF-β1-induced EMT by inhibiting TGF-β1/Smad2/3 signaling pathway in osteosarcoma

Metastatic osteosarcoma usually has an unsatisfactory response to the current standard chemotherapy and causes poor prognosis. Currently, epithelial-mesenchymal transition (EMT) is reported as a critical event in osteosarcoma metastasis. Glaucocalyxin A, a bioactive ent-kauranoid diterpenoid, exerts anti-cancer effect on osteosarcoma by inducing apoptosis in previous study. However, the effect of Glaucocalyxin A on EMT and metastasis of osteosarcoma is unclear. In this study, we investigated the potential mechanisms of Glaucocalyxin A on EMT and metastasis of osteosarcoma. We found that Glaucocalyxin A inhibited migration and invasion of MG-63 and 143B cells. Moreover, Glaucocalyxin A increased the protein and mRNA levels of E-cadherin and decreased the protein and transcription expression of N-cadherin, Vimentin. Glaucocalyxin A also inhibited the protein and mRNA levels of EMT-associated transcription factor including Snail and Slug. Furthermore, Glaucocalyxin A inhibited transforming growth factor-β1 (TGF-β1)-induced migration, invasion and EMT of low-metastatic osteosarcoma U2OS cells. Glaucocalyxin A inhibited TGF-β-induced phosphorylation of Smad 2/3 in osteosarcoma U2OS cells. Finally, we established transplanted metastatic models of highly metastatic osteosarcoma 143B cells. Glaucocalyxin A inhibited lung metastasis in vivo. Interestingly, Glaucocalyxin A increased the protein expression of E-cadherin and reduced the protein expression of N-cadherin and Vimentin. Glaucocalyxin A inhibited the protein expression of Snail and Slug in vivo. In summary, this study demonstrated that Glaucocalyxin A inhibited EMT and TGF-β1-induced EMT by inhibiting TGF-β1/Smad2/3 signaling pathway in osteosarcoma. Therefore, Glaucocalyxin A might be a promising candidate against the metastasis of human osteosarcoma.

Nicotine promotes cervical metastasis of oral cancer by regulating peroxiredoxin 1 and epithelial-mesenchymal transition in mice

Background

Tobacco is a major risk factor for oral squamous cell carcinoma (OSCC). However, the role of nicotine in OSCC is not completely understood.

Materials and methods

To analyze the mechanisms of nicotine-induced cervical metastasis, we investigated whether nicotine induced invasion, migration, and epithelial–mesenchymal transition (EMT) via regulating peroxiredoxin 1 (Prx1) in CAL 27 cells. In addition, we established a mouse model to confirm the roles of nicotine in regulating Ets1/Prx1/EMT signaling in OSCC metastasis.

Results

We showed that nicotine induced CAL 27 cell invasion, migration, EMT, and Prx1 and Ets1 expression. Prx1 knockdown inhibited cell invasion, migration, and EMT. Ets1 silencing downregulated Prx1 expression and EMT. Prx1 and Ets1 were shown to interact in CAL 27 cells treated with nicotine, and nicotine could significantly upregulate the binding of the transcription factor Ets1 to the Prx1 gene promoter region. Additionally, an in vivo study showed that nicotine induced tumor metastasis and EMT. Prx1 knockdown inhibited cervical metastasis rates and EMT progression. No significant differences in metastasis rates and EMT-related marker expression levels were observed between vehicle- and nicotine-treated mice.

Conclusion

The results indicate that nicotine promotes cervical lymph node metastasis through regulating Ets1/Prx1/EMT signaling during OSCC pathogenesis; consequently, Prx1 may represent a potential target for the prevention and treatment of OSCC.

The Crosstalk Between Cell Adhesion and Cancer Metabolism

Cancer cells preferentially use aerobic glycolysis over mitochondria oxidative phosphorylation for energy production, and this metabolic reprogramming is currently recognized as a hallmark of cancer. Oncogenic signaling frequently converges with this metabolic shift, increasing cancer cells' ability to produce building blocks and energy, as well as to maintain redox homeostasis. Alterations in cell-cell and cell-extracellular matrix (ECM) adhesion promote cancer cell invasion, intravasation, anchorage-independent survival in circulation, and extravasation, as well as homing in a distant organ. Importantly, during this multi-step metastatic process, cells need to induce metabolic rewiring, in order to produce the energy needed, as well as to impair oxidative stress. Although the individual implications of adhesion molecules and metabolic reprogramming in cancer have been widely explored over the years, the crosstalk between cell adhesion molecular machinery and metabolic pathways is far from being clearly understood, in both normal and cancer contexts. This review summarizes our understanding about the influence of cell-cell and cell-matrix adhesion in the metabolic behavior of cancer cells, with a special focus concerning the role of classical cadherins, such as Epithelial (E)-cadherin and Placental (P)-cadherin.

Association of low expression of E-cadherin and β-catenin with the progression of early stage human squamous cervical cancer

The precise involvement and mechanisms of human papilloma virus type 16 (HPV16) in epithelial-mesenchymal transition (EMT) of cervical intraepithelial neoplasia (CIN) and squamous cervical cancer (SCC) remain unknown. The present study aimed to examine the expression of EMT indicators and their association with HPV16 in CIN and early stage SCC, and their prognostic value in early stage SCC. The expression levels of E-cadherin, N-cadherin, β-catenin, vimentin, and fibronectin were determined by immunohistochemistry in 40 patients with normal uterine cervix, 22 patients with CIN1, 60 patients with CIN2-3, and 86 patients with SCC, stage Ia-IIa, according to the International Federation of Gynecology and Obstetrics. The expression of the epithelial indicators E-cadherin and β-catenin gradually declined, and the mesenchymal indicators N-cadherin, vimentin, and fibronectin increased with progression of the cervical lesions (P<0.05). Patients with SCC with lymph node metastasis, parametrial invasion, negative E-cadherin, and negative β-catenin expression had shorter overall survival (P=0.001, P=0.015, P=0.014, and P=0.043, respectively) and disease-free survival (P=0.002, P=0.021, P=0.025, and P=0.045, respectively) time. Multivariate survival analysis indicated that lymph node metastasis [Hazard ratio (HR)=3.544; P=0.010], parametrial invasion (HR=2.014; P=0.007) and E-cadherin expression (HR=0.163; P<0.001) were independently associated with overall survival, but also with disease-free survival (HR=3.612, P=0.009; HR=1.935, P=0.011; HR=0.168, P<0.001, respectively). In patients with CINs, HPV16 infection was negatively correlated with the expression of E-cadherin, and positively correlated with the expression of N-cadherin, vimentin, and fibronectin. EMT occurs during the progression of CINs to early stage SCC, and is associated with HPV16 infection in CINs. Lymph node metastasis and parametrial invasion are poor prognostic factors for SCC, while positive E-cadherin expression may serve as a protective prognostic factor for SCC.

TGF-β1 Induces Epithelial-Mesenchymal Transition of Chronic Sinusitis with Nasal Polyps through MicroRNA-21

OBJECTIVES

To characterize the epithelial-mesenchymal transition (EMT) in chronic rhinosinusitis with nasal polyps (CRSwNP) and to investigate the mechanism by which microRNA-21 (miR-21) regulates EMT in CRSwNP.

METHOD

(1) Tissue experiments: Mucosa tissues were collected from 13 patients with CRSwNP and 12 patients with CRS without nasal polyps (CRSsNP), as well as 11 patients without CRS (controls). Protein localization and quantification were achieved by immunofluorescence staining and Western blotting, involving the epithelial marker protein E-cadherin and the mesenchymal marker proteins α-smooth muscle actin (α-SMA), fibronectin, and vimentin. Quantitative RT-PCR was used to detect the relative expression levels of miR-21 and TGF-β1 mRNAs. (2) Cellular experiments: Primary human nasal epithelial cells (PHNECs) treated with TGF-β1, or TGF-β1 with miR-21 inhibitor, or miR-21 mimics alone were observed for morphology changes under a phase-contrast microscope. The expression levels of epithelial/mesenchymal marker proteins were determined as aforementioned. PTEN and phosphorylated Akt were detected by Western blotting.

RESULTS

(1) Tissue experiments: Compared with the CRSsNP and control groups, the expression of E-cadherin was downregulated in the CRSwNP group, whereas the expression of TGF-β1, α-SMA, fibronectin, and vimentin was upregulated. The expression levels of miR-21 and TGF-β1 mRNAs in CRSwNP were significantly higher than those in CRSsNP and controls. (2) Cellular experiments: TGF-β1 induced EMT-like transformation in PHNECs, featured by changes in cell morphology and upregulation of mesenchymal proteins and miR-21. The miR-21 inhibitor, as well as the Akt-specific -inhibitor, suppressed TGF-β1-induced EMT. Mechanically, downregulation of miR-21 resulted in increased PTEN and decreased Akt phosphorylation. Furthermore, overexpression of miR-21 had the opposite effects.

CONCLUSIONS

Our findings suggest that the TGF-β1-miR-21-PTEN-Akt axis may contribute to the pathogenesis of CRSwNP. miR-21 might be a reliable target for treating nasal polyp genesis through EMT suppression. Moreover, miR-21 inhibitors could be a novel class of antipolyp drug that modulates PTEN expression and Akt activation. In addition, further investigation regarding the reason underlying miR-21 overexpression in CRSwNP could provide a molecular target for novel treatment strategies for nasal polyposis.

Heterogeneity in Circulating Tumor Cells: The Relevance of the Stem-Cell Subset

The release of circulating tumor cells (CTCs) into vasculature is an early event in the metastatic process. The analysis of CTCs in patients has recently received widespread attention because of its clinical implications, particularly for precision medicine. Accumulated evidence documents a large heterogeneity in CTCs across patients. Currently, the most accepted view is that tumor cells with an intermediate phenotype between epithelial and mesenchymal have the highest plasticity. Indeed, the existence of a meta-stable or partial epithelial–mesenchymal transition (EMT) cell state, with both epithelial and mesenchymal features, can be easily reconciled with the concept of a highly plastic stem-like state. A close connection between EMT and cancer stem cells (CSC) traits, with enhanced metastatic competence and drug resistance, has also been described. Accordingly, a subset of CTCs consisting of CSC, present a stemness profile, are able to survive chemotherapy, and generate metastases after xenotransplantation in immunodeficient mice. In the present review, we discuss the current evidence connecting CTCs, EMT, and stemness. An improved understanding of the CTC/EMT/CSC connections may uncover novel therapeutic targets, irrespective of the tumor type, since most cancers seem to harbor a pool of CSCs, and disclose important mechanisms underlying tumorigenicity.

Encircling the regions of the pharmacogenomic landscape that determine drug response

BACKGROUND

The integration of large-scale drug sensitivity screens and genome-wide experiments is changing the field of pharmacogenomics, revealing molecular determinants of drug response without the need for previous knowledge about drug action. In particular, transcriptional signatures of drug sensitivity may guide drug repositioning, prioritize drug combinations, and point to new therapeutic biomarkers. However, the inherent complexity of transcriptional signatures, with thousands of differentially expressed genes, makes them hard to interpret, thus giving poor mechanistic insights and hampering translation to clinics.

METHODS

To simplify drug signatures, we have developed a network-based methodology to identify functionally coherent gene modules. Our strategy starts with the calculation of drug-gene correlations and is followed by a pathway-oriented filtering and a network-diffusion analysis across the interactome.

RESULTS

We apply our approach to 189 drugs tested in 671 cancer cell lines and observe a connection between gene expression levels of the modules and mechanisms of action of the drugs. Further, we characterize multiple aspects of the modules, including their functional categories, tissue-specificity, and prevalence in clinics. Finally, we prove the predictive capability of the modules and demonstrate how they can be used as gene sets in conventional enrichment analyses.

CONCLUSIONS

Network biology strategies like module detection are able to digest the outcome of large-scale pharmacogenomic initiatives, thereby contributing to their interpretability and improving the characterization of the drugs screened.

PAR2 Inhibition Enhanced the Sensitivity of Colorectal Cancer Cells to 5-FU and Reduced EMT Signaling

The aim of this study was to investigate the underlying mechanisms that transforming growth factor-β (TGF-β)-mediated epithelial-to-mesenchymal transition (EMT) in tumor cells contributes to 5-FU resistance. A series of experiments involving cell viability and caspase activity analyses, siRNA transfection, RNA isolation, and quantitative-PCR (qPCR) assay, cell migration analysis, Western blotting analysis of total protein and membrane protein were performed in this study. Mouse xenograft model was used to determine the effect of the PAR2 inhibitor in vivo. In this study, we found that protease-activated receptor 2 (PAR2) induction in 5-FU therapy is correlated with TGF-β-mediated EMT and apoptosis resistance. PAR2 and TGF-β were both activated in response to 5-FU treatment in vivo and in vitro, and whereas TGF-β inhibition sensitized CRC cells to 5-FU and suppressed cell migration, PAR2 activation eliminated the effect of TGF-β inhibition. Conversely, siRNA-mediated PAR2 depletion or PAR2 inhibition with a specific inhibitor produced a similar phenotype as TGF-β signal inhibition: 5-FU sensitization and cell migration suppression. Moreover, the results of xenograft experiments indicated that the PAR2 inhibitor can enhance cell killing by 5-FU in vivo and suppress EMT signaling. Our results reveal that the TGF-β effects require the coordinating action of PAR2, suggesting that PAR2 inhibition could be a new therapeutic strategy to combat 5-FU resistance in CRC.

The effect of TWIST silencing in metastatic chordoma cells

Chordoma is a slowly growing and invasive bone tumor  with a tendency to metastasize locally in advanced stages.  It is essential to discover new therapeutics that target genes involved in the metastasis of chordoma. Epithelial-mesenchymal transition (EMT) might robustly influence the metastasis of a tumor bulk. To our knowledge, this is the first time to show that EMT might have a role in chordoma metastasis. In this study, we aim to investigate the possible role of Twist, a key player transcription factor of EMT, in chordoma metastasis. The TWIST gene was silenced by short hairpins in chordoma cell line MUG-Chor1 and effects on metastasis were investigated by wound healing/gap closure and invasion assays. Twist-silenced MUG-Chor1 cells were found to be less migratory and less invasive when compared to the negative control. This study indicates that Twist might have a role in metastatic chordoma cells.

YY1 Complex Promotes Quaking Expression via Super-Enhancer Binding during EMT of Hepatocellular Carcinoma

Quaking (QKI) is an alternative splicing factor that can regulate circRNA formation in the progression of epithelial-mesenchymal transition, but the mechanism remains unclear. High expression of QKI is correlated with short survival time, metastasis, and high clinical stage and pathology grade in hepatocellular carcinoma (HCC). Here we report that transcription of the QKI gene was activated by the Yin-Yang 1 (YY1)/p65/p300 complex, in which YY1 bound to the super-enhancer and promoter of QKI, p65 combined with the promoter, and p300 served as a mediator to maintain the stability of the complex. This YY1/p65/p300 complex increased QKI expression to promote the malignancy of HCC as well as an increased circRNA formation in vitro and in vivo. Hyperoside is one of several plant-derived flavonol glycoside compounds. Through virtual screening and antitumor activity analysis, we found that hyperoside inhibited QKI expression by targeting the YY1/p65/p300 complex. Overall, our study suggests that the regulatory mechanism of QKI depends on the YY1/p65/p300 complex and that it may serve as a potential target for treatment of HCC. SIGNIFICANCE: These findings identify the YY1/p65/p300 complex as a regulator of QKI expression, identifying several potential therapeutic targets for the treatment of HCC.

RPS7 promotes cell migration through targeting epithelial-mesenchymal transition in prostate cancer

OBJECTIVES

Small ribosomal protein subunit 7 (RPS7) is an important structural components of the ribosome involved in protein synthesis, previous studies demonstrated that RPS7 was associated with several malignancies, but the role of RPS7 in prostate cancer (PCa) remains unclear. To decipher such a puzzle, in the current study, we deciphered the role and mechanism of RPS7 during the progression of PCa.

MATERIAL AND METHODS

In this study, the expression of mRNA was performed by quantitative real-time PCR. The protein level was identified by Western blotting. Kaplan-Meier survival analysis was demonstrated the relation between the abnormal expression of RPS7 mRNA and the overall survival. Cell proliferation was assessed by MTT assay and cell counting, meanwhile, cell migration was checked by transwell assay.

RESULTS

RPS7 is higher expressed in PCa (p < 0.001), and the overexpression of RPS7 is closely associated with poor outcome of PCa patients after radical prostatectomy (p < 0.001). Inhibition the expression of RPS7 with a specific RPS7 siRNA could markedly attenuate prostate tumor growth and migration (p < 0.05). Mechanistic data reveals that inhibition of RPS7 could up-regulate the epithelial protein marker, E-cadherin (p < 0.05), and down-regulate the mesenchymal protein markers, such as N-cadherin and Snail (p < 0.001).

CONCLUSIONS

RPS7 is a newly verified tumor promoter in PCa, and promotes cell migration by targeting epithelial-to-mesenchymal transitionpathway. Thus, inhibition of RPS7-epithelial to-mesenchymal transition signaling might represent a prospective approach toward limiting prostate tumor progression.

MiR-146a attenuates liver fibrosis by inhibiting transforming growth factor-β1 mediated epithelial-mesenchymal transition in hepatocytes

Epithelial-mesenchymal transition (EMT) has emerged as a vital process in embryogenesis, carcinogenesis, and tissue fibrosis. Transforming growth factor-beta 1 (TGF-β1)-mediated signaling pathways play important roles in the EMT process. MicroRNA-146a (miR-146a) has been suggested as a significant regulatory molecule in fibrogenesis. Therefore, the present study aimed to evaluate the effect of miR-146a on the EMT of hepatocytes and to investigate the role of overexpressing miR-146a on rat hepatic fibrosis. The results showed that the miR-146a level decreased during the EMT process of L02 hepatocytes induced by TGF-β1 in vitro. Moreover, miR-146a overexpression led to significant reduction of EMT-related markers expression in hepatocytes. Subsequent experiments revealed that miR-146a attenuated the EMT process in hepatocytes by targeting small mothers against decapentaplegic (SMAD) 4. Meanwhile, restoration of SMAD4 expression rescued the inhibitory effect of miRNA-146a on EMT. Further in vivo studies revealed that intravenous injection of miR-146a-expressing adenovirus (Ad-miR-146a) successfully restored the miR-146a levels and mitigated fibrogenesis in the livers of CCl4-treated rats. More importantly, after Ad-miR-146a treatment, inhibition of both EMT traits and SMAD4 expression was observed. The results of the present study showed that miR-146a/SMAD4 is a key signaling cascade that inhibits hepatocyte EMT, and the introduction of miR-146a might present a promising therapeutic option for liver fibrosis.

ZEB1 mediates doxorubicin (Dox) resistance and mesenchymal characteristics of hepatocarcinoma cells

The acquired chemoresistance during long term chemotherapy is one of the most important factors to limit the application of Doxorubicin (Dox) on clinical treatment of hepatocellular carcinoma (HCC) patients. Our present study found that Dox resistant HCC (HCC/Dox) cells had greater capability of in vitro migration and invasion compared to their parental cells. HCC/Dox cells exhibited mesenchymal characteristics, which was evidenced by the up regulation of fibronectin, vimentin while down regulation of E-Cadherin. Zeb1, one powerful epithelial mesenchymal transition related transcription factor (EMT-TF), was markedly upregulated in HCC/Dox cells. Targeted inhibition of Zeb1 via siRNA can suppress the cell migration and re-sensitized cells to Dox treatment. The upregulation of Zeb1 in HCC/Dox cells was due to the increasing protein and mRNA stability of Zeb1. In HCC/Dox cells, the down regulation of SIAH1 mediated the upregulation of protein stability of Zeb1, while decreased levels of miR-3129-5p was responsible for the increasing mRNA stability of Zeb1. Collectively, our data suggested that SIAH1 and miR-3129-5p induced upregulation of Zeb1 mediated the Dox resistance of HCC cells. Targeted inhibition of Zeb1 might be helpful to overcome of Dox resistance of HCC.

Expression of Epithelial-Mesenchymal Transition Proteins in Pancreatic Anaplastic (Undifferentiated) Carcinoma

OBJECTIVES

The aim of this study was to identify an association of pancreatic anaplastic carcinoma (APC) with the epithelial-mesenchymal transition (EMT).

METHODS

Resected APCs (n = 24) were examined to assess components of APCs, including carcinomatous, transitional, and sarcomatous regions. Analysis was performed based on the immunoreactivity of E-cadherin and 3 EMT-related proteins: Slug (zinc finger protein SNAI2), Twist (Twist-related protein 1), and Zeb1 (zinc finger E-box-binding homeobox 1). Expression score was determined based on staining intensity and stained area of the target cells. Finally, we performed a hierarchical clustering based on the expression pattern of E-cadherin and EMT-related proteins of the sarcomatous component.

RESULTS

The expression score of E-cadherin decreased in the order of sarcomatous > transitional > carcinomatous components (P < 0.01). Although there were significant differences in the immunohistochemical scores of Slug, Twist, and Zeb1 between carcinomatous and transitional components (P < 0.01), the significant difference in immunohistochemical score of Zeb1 between transitional and sarcomatous components was found (P < 0.05). Furthermore, APCs were divided into 2 subgroups based on the expression patterns of E-cadherin and EMT-related proteins (hierarchical clustering analysis). Consequently, these subgroups were distinguished by Twist expression.

CONCLUSIONS

Epithelial-mesenchymal transition plays an essential role in the pathogenesis of APC.

The matricellular protein CCN5 inhibits fibrotic deformation of retinal pigment epithelium

Retinal pigment epithelium (RPE) plays an essential role in maintaining retinal function, and its defect is thought to be critically implicated in various ocular disorders. This study demonstrated that the matricellular protein CCN5 was down-regulated in ARPE-19 cells treated with the pro-fibrotic agent transforming growth factor (TGF)-β. A recombinant adenovirus expressing CCN5 (AdCCN5) was used to restore the level of CCN5 in these cells. AdCCN5 prevented TGF-β-induced fibrotic changes, including disruption of tight junctions, up-regulation of mesenchymal marker proteins, and down-regulation of epithelial marker proteins. In addition, AdCCN5 prevented TGF-β-induced functional defects, including increased migratory activity and reduced phagocytic activity. Notably, AdCCN5 reversed morphological and functional defects pre-established by TGF-β prior to viral infection. The CCN5 level was down-regulated in RPE of 18-month-old Ccl2-/- mice, which exhibited retinal defects. Restoration of the CCN5 level via intravitreal injection of a recombinant adeno-associated virus expressing CCN5 (AAV9-CCN5) normalized the altered expression of mesenchymal, epithelial, and functional marker proteins, as assessed by western blotting and immunohistochemistry. Taken together, these data suggest that down-regulation of CCN5 is associated with fibrotic deformation of RPE under pathological conditions and that restoration of the CCN5 level effectively promotes recovery of deformed RPE.

Perspective: Aligned arrays of electrospun nanofibers for directing cell migration

Cell migration plays an important role in a wide variety of biological processes, including embryogenesis, wound healing, inflammation, cancer metastasis, and tissue repair. Electrospun nanofibers have been extensively explored as scaffolds to manipulate cell migration owing to their unique characteristics in mimicking the hierarchical architecture of extracellular matrix. In particular, aligned arrays of electrospun nanofibers are capable of guiding and promoting the directional migration of cells. The physical parameters and properties of the aligned nanofibers, including their size, modulus, and surface chemistry, can all affect the migratory behaviors of cells, while the controlled release of growth factors and drugs from the nanofibers can also be utilized to influence cell migration. By manipulating cell migration, electrospun nanofibers have been applied to promote tissue repair and help eradicate tumors in vivo. In this perspective, we highlight recent developments in collecting electrospun nanofibers as aligned arrays and then illustrate how the aligned nanofibers can be utilized to manipulate cell migration.

An Inhibitor of GSK3B and HDACs Kills Pancreatic Cancer Cells and Slows Pancreatic Tumor Growth and Metastasis in Mice

BACKGROUND & AIMS

Growth, progression, and drug resistance of pancreatic ductal adenocarcinomas (PDACs) have been associated with increased levels and activity of glycogen synthase kinase 3 beta (GSK3B) and histone deacetylases (HDACs). We designed and synthesized molecules that simultaneously inhibit the activities of both enzymes. We tested the effects of one of these molecules, Metavert, in pancreatic cancer cells and mice with pancreatic tumors.

METHODS

We tested the ability of Metavert to bind GSK3B and HDACs using surface plasmon resonance. MIA PaCa-2, Bx-PC3, HPAF-II, and HPDE6 cell lines were incubated with different concentrations of Metavert, with or without paclitaxel or gemcitabine, or with other inhibitors of GSK3B and HDACs; cells were analyzed for apoptosis and migration and by immunoblotting, immunofluorescence, and real-time polymerase chain reaction. Krasþ/LSLG12D;Trp53þ/LSLR172H;Pdx-1-Cre (KPC) mice (2 months old) were given injections of Metavert (5 mg/kg, 3 times/week) or vehicle (control). B6.129J mice with tumors grown from UN-KPC961-Luc cells were given injections of Metavert or vehicle. Tumors and metastases were counted and pancreata were analyzed by immunohistochemistry. Glucose metabolism was measured using 13C-glucose tracer and mass spectroscopy and flow cytometry. Cytokine levels in blood samples were measured using multiplexing enzyme-linked immunosorbent assay.

RESULTS

Metavert significantly reduced survival of PDAC cells but not nontransformed cells; the agent reduced markers of the epithelial-to-mesenchymal transition and stem cells in PDAC cell lines. Cells incubated with Metavert in combination with irradiation and paclitaxel or gemcitabine had reduced survival compared with cells incubated with either agent alone; Metavert increased killing of drug-resistant PDAC cells by paclitaxel and gemcitabine. PDAC cells incubated with Metavert acquired normalized glucose metabolism. Administration of Metavert (alone or in combination with gemcitibine) to KPC mice or mice with syngeneic tumors significantly increased their survival times, slowed tumor growth, prevented tumor metastasis, decreased tumor infiltration by tumor-associated macrophages, and decreased blood levels of cytokines.

CONCLUSIONS

In studies of PDAC cells and 2 mouse models of PDAC, we found a dual inhibitor of GSK3B and HDACs (Metavert) to induce cancer cell apoptosis, reduce migration and expression of stem cell markers, and slow growth of tumors and metastases. Metavert had synergistic effects with gemcitabine.

Alpha-tubulin acetyltransferase/MEC-17 regulates cancer cell migration and invasion through epithelial-mesenchymal transition suppression and cell polarity disruption

MEC-17, a newly identified alpha-tubulin-N-acetyltransferase 1, serves as the major α-tubulin acetyltransferase to promote α-tubulin acetylation in vitro and in vivo. Alteration of α-tubulin acetylation may be involved in morphology regulation, cell migration, and tumour metastasis. However, MEC-17’s role in cell physiology and its effect on epithelial–mesenchymal transition (EMT) and cell polarity remain elusive. In the present study, we characterized the overexpressed or downregulated cell models through gene targeting as MEC-17 gain- or loss-of-function. Overexpression of MEC-17 enhanced the cell spreading area, suppressed pseudopods formation in a three-dimensional (3D) culture system, and inhibited cancer cell migratory and invasive ability and tumour metastasis by orthotopic lung cancer animal model. Furthermore, morphological change and migration inhibition of cancer cells were accompanied by EMT repression, Golgi reorientation, and polarity disruption caused by alteration of cdc42 activity via a decrease in Rho-GAP, ARHGAP21. By contrast, a reduction in endogenous MEC-17 accelerated the pseudopods formation and EMT, and facilitated cell migration and invasion. These results demonstrated the crucial role of MEC-17 in the modulation of intrinsic cell morphogenesis, migration, and invasive function through regulation of EMT and cell polarity.

miR-30a Inhibits Melanoma Tumor Metastasis by Targeting the E-cadherin and Zinc Finger E-box Binding Homeobox 2

Background:

Epithelial–mesenchymal transition (EMT) is actively involved in tumor invasion. The main hallmark of EMT is downregulation of the adherens junction protein E-cadherin due to transcriptional repression. Candidate E-cadherin transcription repressors are members of ZEB family, ZEB2 belong to the ZEB family transcription factor that is pivotal for embryonic development and tumor progression. ZEB2 (zinc finger E-box binding homeobox 2) is most widely known as an inducer of EMT. Growing evidence have shown the involvement of microRNAs in cancer progression. In this study, we demonstrate that miR-30a is a potent suppressor of melanoma metastasis to the lung.

Materials and Methods:

In this study, miR-30a has been transfected into B16-F10 melanoma cells, and then cells were injected intravenously into C57BL/6 mice. Then, the mice were sacrificed and nodules in the lungs were enumerated.

Results:

Ectopic expression of miR-30a in melanoma cell line resulted in the suppression of pulmonary metastasis. We also found that transfected miR-30a into melanoma cells could increase E-cadherin and decrease ZEB2 expression.

Conclusions:

Our findings showed that increased expression of miR-30a in melanoma inhibited metastasis in vivo by targeting ZEB2 and E-cadherin.

Galectin-3 and cancer stemness

Over the last few decades galectin-3, a carbohydrate binding protein, with affinity for N-acetyllactosamine residues, has been unique due to the regulatory roles it performs in processes associated with tumor progression and metastasis such as cell proliferation, homotypic/heterotypic aggregation, dynamic cellular transformation, migration and invasion, survival and apoptosis. Structure-function association of galectin-3 reveals that it consists of a short amino terminal motif, which regulates its nuclear-cytoplasmic shuttling; a collagen α-like domain, susceptible to cleavage by matrix metalloproteases and prostate specific antigen; accountable for its oligomerization and lattice formation, and a carbohydrate-recognition/binding domain containing the anti-death motif of the Bcl2 protein family. This structural complexity permits galectin-3 to associate with numerous molecules utilizing protein-protein and/or protein-carbohydrate interactions in the extra-cellular as well as intracellular milieu and regulate diverse signaling pathways, a number of which appear directed towards epithelial-mesenchymal transition and cancer stemness. Self-renewal, differentiation, long-term culturing and drug-resistance potential characterize cancer stem cells (CSCs), a small cell subpopulation within the tumor that is thought to be accountable for heterogeneity, recurrence and metastasis of tumors. Despite the fact that association of galectin-3 to the tumor stemness phenomenon is still in its infancy, there is sufficient direct evidence of its regulatory roles in CSC-associated phenotypes and signaling pathways. In this review, we have highlighted the available data on galectin-3 regulated functions pertinent to cancer stemness and explored the opportunities of its exploitation as a CSC marker and a therapeutic target.

Knockdown on aPKC-ι inhibits epithelial-mesenchymal transition, migration and invasion of colorectal cancer cells through Rac1-JNK pathway

BACKGROUND

Atypical protein kinase C-ι (aPKC-ι) is an oncogenic factor, and required for the epithelial-mesenchymal transition (EMT) of different types of cancer. Our study aimed to investigate the role of aPKC-ι in the EMT, migration and invasion of colorectal cancer (CRC) cells.

METHODS

Expression of aPKC-ι was evaluated in CRC cell lines treated with TGF-β1 using qPCR and western blot. After aPKC-ι was knocked down using shRNA, migration and invasion abilities of CRC cell lines were evaluated by wound healing assay and transwell assay, respectively. Activation status of downstream signaling factors of aPKC-ι, including Rac1, JNK, STAT3 and β-catenin, was measured using western blot. Furthermore, auranofin, an aPKC-ι inhibitor, was used to treat CRC cell lines to investigate its possible inhibition on the EMT of CRC cell lines, as well as on the expression of aPKC-ι and its downstream signaling factors.

RESULTS

TGF-β1 induced the expression of aPKC-ι in CRC cells, and knockdown on aPKC-ι inhibited the TGF-β1-induced EMT, migration and invasion of CRC cells. Interestingly, Rac1 GTPase level was decreased when aPKC-ι was knocked down, and overexpression of Rac1G12V rescued the cell EMT, migration and invasion in CRC cells as inhibited by sh-aPKC-ι. Moreover, knockdown on aPKC-ι suppressed the phosphorylation of JNK and STAT3, and nuclear translocation of β-catenin. The aPKC- ι inhibitor, Auranofin, showed similar inhibitory effects as aPKC-ι knockdown.

CONCLUSION

Knockdown on aPKC-ι inhibited the EMT, migration and invasion of CRC cells through suppressing of Rac1-JNK pathway. Those findings indicate that aPKC-ι may serve as a novel therapeutic target for CRC.

Lipocalin 2: a potential therapeutic target for breast cancer metastasis

Although systematic therapeutic approaches have reduced cancer-associated mortality, metastatic breast cancer can still evade therapy, particularly triple-negative breast cancer, which remains associated with high rates of cancer metastasis and has the worst clinical prognosis. Lipocalin 2 (LCN2) is a secreted glycoprotein that transports small lipophilic ligands. Its abnormal expression serves critical roles in the epithelial-to-mesenchymal transition process, angiogenesis, and cell migration and invasion in breast cancer. Notably, LCN2 functions as an initiator of carcinogenesis and metastasis by involving multiple signaling pathways. The present review aims to summarize research findings on the abnormal expression of LCN2 in breast cancer progression. Furthermore, the review highlights the latest developments of potential LCN2-targeting agents and proposed LCN2-associated molecular mechanisms with regard to breast cancer invasion and metastasis.

Receptor Tyrosine Kinase-Targeted Cancer Therapy

In the past two decades, several molecular targeted inhibitors have been developed and evaluated clinically to improve the survival of patients with cancer. Molecular targeted inhibitors inhibit the activities of pathogenic tyrosine kinases. Particularly, aberrant receptor tyrosine kinase (RTK) activation is a potential therapeutic target. An increased understanding of genetics, cellular biology and structural biology has led to the development of numerous important therapeutics. Pathogenic RTK mutations, deletions, translocations and amplification/over-expressions have been identified and are currently being examined for their roles in cancers. Therapies targeting RTKs are categorized as small-molecule inhibitors and monoclonal antibodies. Studies are underway to explore abnormalities in 20 types of RTK subfamilies in patients with cancer or other diseases. In this review, we describe representative RTKs important for developing cancer therapeutics and predicting or evaluated resistance mechanisms.

An Optically Induced Dielectrophoresis (ODEP)-Based Microfluidic System for the Isolation of High-Purity CD45neg/EpCAMneg Cells from the Blood Samples of Cancer Patients-Demonstration and Initial Exploration of the Clinical Significance of These Cells

Circulating tumour cells (CTCs) in blood circulation play an important role in cancer metastasis. CTCs are generally defined as the cells in circulating blood expressing the surface antigen EpCAM (epithelial cell adhesion molecule). Nevertheless, CTCs with a highly metastatic nature might undergo an epithelial-to-mesenchymal transition (EMT), after which their EpCAM expression is downregulated. In current CTC-related studies, however, these clinically important CTCs with high relevance to cancer metastasis could be missed due to the use of the conventional CTC isolation methodologies. To precisely explore the clinical significance of these cells (i.e., CD45^neg/EpCAM^neg cells), the high-purity isolation of these cells from blood samples is required. To achieve this isolation, the integration of fluorescence microscopic imaging and optically induced dielectrophoresis (ODEP)-based cell manipulation in a microfluidic system was proposed. In this study, an ODEP microfluidic system was developed. The optimal ODEP operating conditions and the performance of live CD45^neg/EpCAM^neg cell isolation were evaluated. The results demonstrated that the proposed system was capable of isolating live CD45^neg/EpCAM^neg cells with a purity as high as 100%, which is greater than the purity attainable using the existing techniques for similar tasks. As a demonstration case, the cancer-related gene expression of CD45^neg/EpCAM^neg cells isolated from the blood samples of healthy donors and cancer patients was successfully compared. The initial results indicate that the CD45^neg/EpCAM^neg nucleated cell population in the blood samples of cancer patients might contain cancer-related cells, particularly EMT-transformed CTCs, as suggested by the high detection rate of vimentin gene expression. Overall, this study presents an ODEP microfluidic system capable of simply and effectively isolating a specific, rare cell species from a cell mixture.

Downregulation of FOXO6 in breast cancer promotes epithelial-mesenchymal transition and facilitates migration and proliferation of cancer cells

Purpose

Increasing evidence indicates that members of forkhead transcription factor family (FOXO) play key roles in cell proliferation and apoptosis in multiple cancers, including prostate cancer. However, the underlying mechanism of FOXO6 was not yet known. The aim of our work is to investigate the function of FOXO6 in breast cancer.

Methods

In the present study, quantitative real-time polymerase chain reaction and Western blotting analyses were used to detect the expression of FOXO6 in breast cancer tissues and cell lines.

Results

The results revealed that FOXO6 was downregulated in breast cancer tissues and cell lines, compared with adjacent normal tissues and MCF-10A cells, respectively. Moreover, the expression of FOXO6 was associated with the expression of epithelial–mesenchymal transition (EMT) indicator proteins, such as E-cadherin and N-cadherin. Additionally, our findings suggested that FOXO6 expression was negatively associated with tumor size (p=0.002), pathological grade (p=0.018) and lymph node metastasis (p=0.003). Sirt6 has been found to promote cell proliferation and metastasis in several cancers, and quantitative chromatin immunoprecipitation and luciferase reporter assays indicated FOXO6 transcriptionally regulated Sirt6 expression. Furthermore, various functional experiments, including wound healing assay, transwell invasion assay, colony formation assay and Cell Counting Kit-8 assay, revealed that FOXO6 suppressed cell migration, invasion, and proliferation of breast cancer cells.

Conclusion

In conclusion, FOXO6 serves as a tumor suppressor in breast cancer, and suppresses EMT through regulation of Sirt6.

Single Nucleotide Polymorphism in SMAD7 and CHI3L1 and Colorectal Cancer Risk

Colorectal cancer (CRC) is one of the leading cancers throughout the world. It represents the third most common cancer and the fourth in mortality. Most of CRC are sporadic, arise with no known high-penetrant genetic variation and with no previous family history. The etiology of sporadic CRC is considered to be multifactorial and arises from the interaction of genetic variants of low-penetrant genes and environmental risk factors. The most common well-studied genetic variation is single nucleotide polymorphisms (SNPs). SNP arises as a point mutation. If the frequency of the sequence variation reaches 1% or more in the population, it is referred to as polymorphism, but if it is lower than 1%, the allele is typically considered as a mutation. Lots of SNPs have been associated with CRC development and progression, for example, genes of TGF-β1 and CHI3L1 pathways. TGF-β1 is a pleiotropic cytokine with a dual role in cancer development and progression. TGF-β1 mediates its actions through canonical and noncanonical pathways. The most important negative regulatory protein for TGF-β1 activity is termed SMAD7. The production of TGF-β can be controlled by another protein called YKL-40. YKL-40 is a glycoprotein with an important role in cancer initiation and metastasis. YKL-40 is encoded by the CHI3L1 gene. The aim of the present review is to give a brief introduction of CRC, SNP, and examples of some SNPs that have been documented to be associated with CRC. We also discuss two important signaling pathways TGF-β1 and CHI3L1 that influence the incidence and progression of CRC.

Betulinic acid inhibits stemness and EMT of pancreatic cancer cells via activation of AMPK signaling

Cancer stem cells (CSCs), which are found in various types of human cancer, including pancreatic cancer, possess elevated metastatic potential, lead to tumor recurrence and cause chemoradiotherapy resistance. Alterations in cellular bioenergetics through the regulation of 5′ adenosine monophosphate-activated protein kinase (AMPK) signaling may be a prerequisite to stemness. Betulinic acid (BA) is a well-known bioactive compound with antiretroviral and anti-inflammatory potential, which has been reported to exert anticancer effects on various types of cancer, including pancreatic cancer. The present study aimed to investigate whether BA could inhibit pancreatic CSCs via regulation of AMPK signaling. The proliferation of pancreatic cancer cells was examined by MTT and colony formation assays. The migratory and invasive abilities of pancreatic cancer cells were assessed using wound-scratch and Transwell invasion assays. In addition, the expression levels of candidate genes were measured by reverse transcription-quantitative polymerase chain reaction and western blotting. The results revealed that BA inhibited the proliferation and tumorsphere formation of pancreatic cancer cells, suppressed epithelial-mesenchymal transition (EMT), migration and invasion, and reduced the expression of three pluripotency factors [SRY-box 2 (Sox2), octamer-binding protein 4 (Oct4) and Nanog]. Furthermore, immunohistochemical analysis confirmed that there was a significant inverse association between the expression levels of phosphorylated (P)-AMPK and Sox2 in pancreatic cancer, and it was revealed that BA may activate AMPK signaling. Notably, knockdown of AMPK reversed the suppressive effects of BA on EMT and stemness of pancreatic cancer cells. In addition, BA reversed the effects of gemcitabine on stemness and enhanced the sensitivity of pancreatic cancer cells to gemcitabine. Collectively, these results indicated that BA may effectively inhibit pluripotency factor expression (Sox2, Oct4 and Nanog), EMT and the stem-like phenotype of pancreatic cancer cells via activating AMPK signaling. Therefore, BA may be considered an attractive therapeutic candidate and an effective inhibitor of the stem-like phenotype in pancreatic cancer cells. Further investigation into the development of BA as an anticancer drug is warranted.

Characterization of septin expression in normal and fibrotic kidneys

Chronic kidney disease (CKD) is characterized by the loss of nephrons and worsening organ-fibrosis that leads to deterioration and ultimately the total breakdown of kidney function. Renal fibrosis has become a major public health problem worldwide and necessitates hemodialysis and kidney transplantation in affected patients. CKD is mainly characterized by the activation and proliferation of interstitial fibroblasts and by excessive synthesis and accumulation of extracellular matrix components, causing the disruption of the normal tissue architecture of the kidney. Septins are GTPase proteins associated with membranes, actin filaments, and microtubules and are undoubtedly crucial for cytoskeleton organization. Although some septins are involved in liver fibrosis, they have not been investigated in the context of renal fibrosis. Here, we show that numerous septins are expressed in the healthy kidney and demonstrate in fibrotic mouse kidneys that various septins are remarkably up-regulated in the tubulointerstitium compared to contralateral control kidneys. We observed the same findings in human fibrotic kidneys. In both healthy and fibrotic kidneys, septins are coexpressed with extracellular matrix components, reinforcing the structural function of septins as cytoskeletal components. Furthermore, we could show in septin 8-deficient mice that septin 8 is dispensable for the formation of renal fibrosis, and that no other septin was compensatory changed in kidneys compared to wild-type mice.

Chromium(VI) promotes cell migration through targeting epithelial-mesenchymal transition in prostate cancer

Chromium (Cr) is widely used in industry, making its toxicity a matter of concern. Although hexavalent Cr [Cr(VI)] can promote cancer cell proliferation in several cancers, there is little evidence implicating Cr(VI) in cancer cell migration, especially in prostate cancer. We show that the Cr concentration is higher in the serum of prostate cancer patients, and is closely associated with unfavorable outcomes for the patients. Additionally, low dose trivalent Cr [Cr(III)] exposure has no obvious carcinogenic effects in prostate cancer. However, Cr(VI) can promote proliferation and invasion of prostate cancer cell line PC3 cells in vitro and in vivo. In seeking the molecular mechanism of Cr(VI) exposure on cancer progression, we found that Cr(VI) could down-regulate the epithelial protein marker, E-cadherin, and up-regulate mesenchymal protein markers, such as N-cadherin and Snail. Together, these data indicate that Cr(VI) is a newly verified carcinogen in prostate cancer, and can promote cell migration by affecting the Epithelial-Mesenchymal Transition (EMT) pathway. Thus, inhibition of Cr(VI)-EMT signaling is a prospective approach toward limiting prostate tumor progression.

Coregulation of alternative splicing by hnRNPM and ESRP1 during EMT

The epithelial-mesenchymal transition (EMT) is a fundamental developmental process that is abnormally activated in cancer metastasis. Dynamic changes in alternative splicing occur during EMT. ESRP1 and hnRNPM are splicing regulators that promote an epithelial splicing program and a mesenchymal splicing program, respectively. The functional relationships between these splicing factors in the genome scale remain elusive. Comparing alternative splicing targets of hnRNPM and ESRP1 revealed that they coregulate a set of cassette exon events, with the majority showing discordant splicing regulation. Discordant splicing events regulated by hnRNPM show a positive correlation with splicing during EMT; however, concordant events do not, indicating the role of hnRNPM in regulating alternative splicing during EMT is more complex than previously understood. Motif enrichment analysis near hnRNPM-ESRP1 coregulated exons identifies guanine-uridine rich motifs downstream from hnRNPM-repressed and ESRP1-enhanced exons, supporting a general model of competitive binding to these cis-elements to antagonize alternative splicing. The set of coregulated exons are enriched in genes associated with cell migration and cytoskeletal reorganization, which are pathways associated with EMT. Splicing levels of coregulated exons are associated with breast cancer patient survival and correlate with gene sets involved in EMT and breast cancer subtyping. This study identifies complex modes of interaction between hnRNPM and ESRP1 in regulation of splicing in disease-relevant contexts.

RCAN1.4 acts as a suppressor of cancer progression and sunitinib resistance in clear cell renal cell carcinoma

Clear cell renal cell carcinoma (ccRCC) is one of the most common malignant tumors in the urinary system, and its incidence continues to increase. Regulator of calcineurin 1 (RCAN1), one of the genes on chromosome 21, is a crucial mediator of tumor inhibition. RCAN1.4 is best characterized as an endogenous inhibitor of the phosphatase calcineurin, and it has been observed to be downregulated in numerous types of cancer. However, its essential function remains unclear in ccRCC. In the present study, we found that RCAN1.4 expression was frequently downregulated in renal cell carcinoma tissues and cells and was inversely correlated with various clinicopathological parameters. Low RCAN1.4 expression was associated with poor overall survival and disease-free survival and could act as a diagnostic indicator in ccRCC patients. Furthermore, the overexpression of RCAN1.4 inhibited cell proliferation, migration and invasion, whereas RCAN1.4 knockdown promoted these functions in ccRCC cell lines. In addition, RCAN1.4 expression was downregulated in sunitinib-resistant renal cancer cell lines, and inhibition of RCAN1.4 promoted sunitinib resistance. We also found that RCAN1.4 could regulate epithelial-mesenchymal transition (EMT) and the expression of HIF2α in sunitinib-resistant cell lines. Taken together, these findings indicate that downregulation of RCAN1.4 may be crucial for the metastasis of ccRCC and may induce sunitinib resistance. RCAN1.4 may act as a prognostic indicator and potential therapeutic target for ccRCC.

Biemamides A-E, Inhibitors of the TGF-β Pathway That Block the Epithelial to Mesenchymal Transition

Screening of a marine natural products library for inhibitors of TGF-β revealed five pyrimidinedione derivatives, biemamides A-E (1-5). The structures were determined by 2D NMR and HRMS experiments; absolute configurations were established by advanced Marfey's analysis and ECD calculations. Biemamides A-E specifically inhibited in vitro TGF-β induced epithelial to mesenchymal transition in NMuMG cells. Additionally, using Caenorhabditis elegans, selected biemmamides were found to influence in vivo developmental processes related to body size regulation in a dose-dependent manner.

Roles of miR-200 family members in lung cancer: more than tumor suppressors

miRNAs are a class of single-stranded noncoding RNAs, which have no coding potential, but modulate many molecular mechanisms including cancer pathogenesis. miRNAs participate in cell proliferation, differentiation, apoptosis, as well as carcinogenesis or cancer progression, and their involvement in lung cancer has been recently shown. They are suggested to have bidirectional functions on important cancer-related genes so as to enhance or attenuate tumor genesis. Epithelial-mesenchymal transition (EMT) is a fundamental process which contributes to integrity of organogenesis and tissue differentiation as well as tissue repair, organ fibrosis and the progression of carcinoma, and several miRNAs were suggested to form the network regulating EMT in lung cancer, among which, miR-200 family members (miR-200a, miR-200b, miR-200c, miR-429 and miR-141) play crucial roles in the suppression of EMT.