Knockdown of astrocyte elevated gene-1 (AEG-1) in cervical cancer cells decreases their invasiveness, epithelial to mesenchymal transition, and chemoresistance

A Tumor Suppressive Role of CYLD as a Novel Potential DUB of Aurora B in Cervical Cancer

Background

Cervical cancer is a common leading cause of cancer related to women death worldwide. Cylindromatosis (CYLD) is known as an important tumor suppressor in various human cancers, and a deubiquitination enzyme (DUB) as well. Previously, we identified Skp2 as an E3 ligase of Aurora B ubiquitination, but the DUB of Aurora B still remains unknown.

Methods

Aurora B ubiquitination site is identified through in vivo ubiquitination assay. Activity of Aurora B and CENPA was detected by immunoblotting (IB) and immunofluorescence (IF) assay. Protein-to-protein interaction was investigated by immunoprecipitation (IP). Cell chromosome dynamics was monitored by live-cell time-lapse Imaging. Cancer cell proliferation, colony formation, apoptosis, and cell invasion and migration assays were also performed. Protein level was checked by immunohistochemical (IHC) staining in clinical cervical cancer samples.

Results

We identified Lysine 115 (K115) as the main Aurora B ubiquitination site for Skp2. We could also detect an interaction of Aurora B with the DUB CYLD. We found that CYLD promoted deubiquitination of Aurora B, and regulated Aurora B activity and function as well. Compared with control, we found it took more time for the cells to finish cell mitosis with CYLD over-expression. Furthermore, we found that CYLD deficiency promoted cervical cancer cell proliferation, colony formation, cell migration and invasion, and inhibited apoptosis instead, whereas it is just opposite with CYLD over-expression. In clinical cervical cancer samples, we showed a negative correlation of CYLD expression with Aurora B activation and histological cancer cell invasion. Furthermore, there was less CYLD abundance and higher Aurora B activity in advanced cancer samples compared with early stage.

Conclusions

Our findings uncover CYLD as a novel potential DUB of Aurora B, which inhibits Aurora B activation and its subsequent function in cell mitosis, and also provide more evidence for its tumor suppressor function in cervical cancer.

Metadherin (AEG-1/MTDH/LYRIC) expression: Significance in malignancy and crucial role in colorectal cancer

Metadherin (AEG-1/MTDH/LYRIC) is a 582-amino acid transmembrane protein, encoded by a gene located at chromosome 8q22, and distributed throughout the cytoplasm, peri-nuclear region, nucleus, and nucleolus as well as the endoplasmic reticulum (ER). It contains several structural and interacting domains through which it interacts with transcription factors such as nuclear factor-κB (NF-κB), promyelocytic leukemia zinc finger (PLZF), staphylococcal nuclease domain containing 1 (SND1) and lung homing domain (LHD). It is regulated by miRNAs and mediates its oncogenic function via activation of cell proliferation, survival, migration and metastasis, as well as, angiogenesis and chemoresistance via phosphatidylinositol-3-kinase/AKT (PI3K/AKT), NF-κB, mitogen-activated protein kinase (MAPK) and Wnt signaling pathways. In this chapter, metadherin is reviewed highlighting its role in mediating growth, metastasis and chemoresistance in colorectal cancer (CRC). Metadherin, as well as its variants, and antibodies are associated with CRC progression, poorer prognosis, decreased survival and advanced clinico-pathology. The potential of AEG-1/MTDH/LYRIC as a diagnostic and prognostic marker as well as a therapeutic target in CRC is explored.

Metadherin-mediated mechanisms in human malignancies

Metadherin (MTDH) has been recognized as a novel protein that is critical for the progression of multiple types of human malignancies. Studies have reported that MTDH enhances the metastatic potential of cancer cells by regulating multiple signaling pathways. miRNAs and various tumor-related proteins have been shown to interact with MTDH, making it a potential therapeutic target as well as a biomarker in human malignancies. MTDH plays a critical role in inflammation, angiogenesis, hypoxia, epithelial-mesenchymal transition and autophagy. In this review, we present the function and mechanisms of MTDH for cancer initiation and progression.

The Expression of Circulating miR-497 and Metadherin in Hepatocellular Carcinoma: Relation to the Tumor Characteristics and Patients' Survival

Objectives: This study aimed to evaluate the prognostic significance and relationship of miR-497 and metadherin to hepatocellular carcinoma (HCC) tumor characteristics and patients’ survival. Methods: This study enrolled 120 (60 HCC patients and 60 healthy) subjects. Serum miR-497 and metadherin mRNA relative expression were analyzed by real-time quantitative reverse transcription polymerase chain reaction. The overall survival (OS) of HCC patients was assessed using the Kaplan–Meier curve and log-rank test. Results: Serum miR-497 showed statistically significant downregulation in HCC patients compared to controls (p < 0.001). Serum metadherin mRNA relative expression was significantly upregulated in HCC patients compared to controls (p < 0.001). Both serum miR-497 and metadherin mRNA expression were significantly associated with the number of tumor foci (p = 0.028 and 0.001, respectively), tumor size (p = 0.022 and <0.001, respectively), nodal metastasis (p = 0.003 and 0.003, respectively), distant metastasis (p = 0.003 and 0.003, respectively), vascular invasion (p = 0.040 and <0.001, respectively), and BCLC staging (p = 0.043 and 0.004, respectively). The overall survival was lower in patients with low miR-497 expression (p = 0.046) and in patients with high metadherin expression (p < 0.001). Conclusions: The expression levels of miR-497 showed downregulation in HCC patients, but metadherin expression showed upregulation. Both markers were inversely related and closely correlated with tumor characteristics and patients’ survival.

Emerging Role and Clinicopathological Significance of AEG-1 in Different Cancer Types: A Concise Review

Tumor breakthrough is driven by genetic or epigenetic variations which assist in initiation, migration, invasion and metastasis of tumors. Astrocyte elevated gene-1 (AEG-1) protein has risen recently as the crucial factor in malignancies and plays a potential role in diverse complex oncogenic signaling cascades. AEG-1 has multiple roles in tumor growth and development and is found to be involved in various signaling pathways of: (i) Ha-ras and PI3K/AKT; (ii) the NF-κB; (iii) the ERK or mitogen-activated protein kinase and Wnt or β-catenin and (iv) the Aurora-A kinase. Recent studies have confirmed that in all the hallmarks of cancers, AEG-1 plays a key functionality including progression, transformation, sustained angiogenesis, evading apoptosis, and invasion and metastasis. Clinical studies have supported that AEG-1 is actively intricated in tumor growth and progression which includes esophageal squamous cell, gastric, colorectal, hepatocellular, gallbladder, breast, prostate and non-small cell lung cancers, as well as renal cell carcinomas, melanoma, glioma, neuroblastoma and osteosarcoma. Existing studies have reported that AEG-1 expression has been induced by Ha-ras through intrication of PI3K/AKT signaling. Conversely, AEG-1 also activates PI3K/AKT pathway and modulates the defined subset of downstream target proteins via crosstalk between the PI3K/AKT/mTOR and Hedgehog signaling cascade which further plays a crucial role in metastasis. Thus, AEG-1 may be employed as a biomarker to discern the patients of those who are likely to get aid from AEG-1-targeted medication. AEG-1 may play as an effective target to repress tumor development, occlude metastasis, and magnify the effectiveness of treatments. In this review, we focus on the molecular mechanism of AEG-1 in the process of carcinogenesis and its involvement in regulation of crosstalk between the PI3K/AKT/mTOR and Hedgehog signaling. We also highlight the multifaceted functions, expression, clinicopathological significance and molecular inhibitors of AEG-1 in various cancer types.

Therapy Resistance in Cancers: Phenotypic, Metabolic, Epigenetic and Tumour Microenvironmental Perspectives

BACKGROUND

Chemoresistance is a vital problem in cancer therapy where cancer cells develop mechanisms to encounter the effect of chemotherapeutics, resulting in cancer recurrence. In addition, chemotherapy- resistant leads to the formation of a more aggressive form of cancer cells, which, in turn, contributes to the poor survival of patients with cancer.

OBJECTIVE

In this review, we aimed to provide an overview of how the therapy resistance property evolves in cancer cells, contributing factors and their role in cancer chemoresistance, and exemplified the problems of some available therapies.

METHODS

The published literature on various electronic databases including, Pubmed, Scopus, Google scholar containing keywords cancer therapy resistance, phenotypic, metabolic and epigenetic factors, were vigorously searched, retrieved and analyzed.

RESULTS

Cancer cells have developed a range of cellular processes, including uncontrolled activation of Epithelial- Mesenchymal Transition (EMT), metabolic reprogramming and epigenetic alterations. These cellular processes play significant roles in the generation of therapy resistance. Furthermore, the microenvironment where cancer cells evolve effectively contributes to the process of chemoresistance. In tumour microenvironment immune cells, Mesenchymal Stem Cells (MSCs), endothelial cells and cancer-associated fibroblasts (CAFs) contribute to the maintenance of therapy-resistant phenotype via the secretion of factors that promote resistance to chemotherapy.

CONCLUSION

To conclude, as these factors hinder successful cancer therapies, therapeutic resistance property of cancer cells is a subject of intense research, which in turn could open a new horizon to aim for developing efficient therapies.

Multifunctional Role of Astrocyte Elevated Gene-1 (AEG-1) in Cancer: Focus on Drug Resistance

Simple Summary

Chemotherapy is a major mode of treatment for cancers. However, cancer cells adapt to survive in stressful conditions and in many cases, they are inherently resistant to chemotherapy. Additionally, after initial response to chemotherapy, the surviving cancer cells acquire new alterations making them chemoresistant. Genes that help adapt the cancer cells to cope with stress often contribute to chemoresistance and one such gene is Astrocyte elevated gene-1 (AEG-1). AEG-1 levels are increased in all cancers studied to date and AEG-1 contributes to the development of highly aggressive, metastatic cancers. In this review, we provide a comprehensive description of the mechanism by which AEG-1 augments tumor development with special focus on its ability to regulate chemoresistance. We also discuss potential ways to inhibit AEG-1 to overcome chemoresistance.

Abstract

Cancer development results from the acquisition of numerous genetic and epigenetic alterations in cancer cells themselves, as well as continuous changes in their microenvironment. The plasticity of cancer cells allows them to continuously adapt to selective pressures brought forth by exogenous environmental stresses, the internal milieu of the tumor and cancer treatment itself. Resistance to treatment, either inherent or acquired after the commencement of treatment, is a major obstacle an oncologist confronts in an endeavor to efficiently manage the disease. Resistance to chemotherapy, chemoresistance, is an important hallmark of aggressive cancers, and driver oncogene-induced signaling pathways and molecular abnormalities create the platform for chemoresistance. The oncogene Astrocyte elevated gene-1/Metadherin (AEG-1/MTDH) is overexpressed in a diverse array of cancers, and its overexpression promotes all the hallmarks of cancer, such as proliferation, invasion, metastasis, angiogenesis and chemoresistance. The present review provides a comprehensive description of the molecular mechanism by which AEG-1 promotes tumorigenesis, with a special emphasis on its ability to regulate chemoresistance.

The Scope of Astrocyte Elevated Gene-1/Metadherin (AEG-1/MTDH) in Cancer Clinicopathology: A Review

Since its initial cloning in 2002, a plethora of studies in a vast number of cancer indications, has strongly established AEG-1 as a bona fide oncogene. In all types of cancer cells, overexpression and knockdown studies have demonstrated that AEG-1 performs a seminal role in regulating proliferation, invasion, angiogenesis, metastasis and chemoresistance, the defining cancer hallmarks, by a variety of mechanisms, including protein-protein interactions activating diverse oncogenic pathways, RNA-binding promoting translation and regulation of inflammation, lipid metabolism and tumor microenvironment. These findings have been strongly buttressed by demonstration of increased tumorigenesis in tissue-specific AEG-1 transgenic mouse models, and profound resistance of multiple types of cancer development and progression in total and conditional AEG-1 knockout mouse models. Additionally, clinicopathologic correlations of AEG-1 expression in a diverse array of cancers establishing AEG-1 as an independent biomarker for highly aggressive, chemoresistance metastatic disease with poor prognosis have provided a solid foundation to the mechanistic and mouse model studies. In this review a comprehensive analysis of the current and up-to-date literature is provided to delineate the clinical significance of AEG-1 in cancer highlighting the commonality of the findings and the discrepancies and discussing the implications of these observations.

Molecular landscape of recurrent cervical cancer

Cervical cancer (CC) is a major gynecological problem in developing and underdeveloped countries. Despite the significant advancement in early detection and treatment modalities, several patients recur. Moreover, the molecular mechanisms responsible for CC recurrence remains obscure. The patients with CC recurrence often show poor prognosis and significantly high mortality rates. The clinical management of recurrent CC depends on treatment history, site, and extent of the recurrence. Owing to poor prognosis and limited treatment options, recurrent CC often presents a challenge to the clinicians. Several in vitro, in vivo, and patient studies have led to the identification of the critical molecular changes responsible for CC recurrence. Both aberrant genetic and epigenetic modifications leading to altered cell signaling pathways have been reported to impact CC recurrence. Researchers are currently trying to dissect the molecular pathways in CC and translate these findings for better management of disease. This article attempts to review the existing knowledge of disease relapse, accompanying challenges, and associated molecular players in CC.

MicroRNA-21 promotes cell metastasis in cervical cancer through modulating epithelial-mesenchymal transition

MicroRNA (miR)-21 is known to act as an oncogene in cervical cancer by promoting cell proliferation and migration; however, the underlying molecular mechanisms have remained to be fully elucidated. The present study revealed that the gene expression levels of miR-21 and epithelial-mesenchymal transition (EMT)-associated transcription factor Zinc finger E-box-binding homeobox 1 (ZEB1), in cervical cancer and lymphatic metastatic carcinoma tissues were significantly higher than those in normal tissues (P<0.05). Furthermore, the gene expression levels of miR-21 and ZEB1 were positively associated with muscular infiltration depth, parametrical invasion and lymph node metastasis in patients with cervical cancer. Immunohistochemistry assays indicated that the expression levels of ZEB1 and the mesenchymal cell marker Vimentin in cervical cancer tissues were significantly higher than those in normal cervical tissues (P<0.05). Overexpression of miR-21 in HeLa and SiHa cells caused the upregulation of the mesenchymal cell markers Vimentin and N-cadherin, and downregulation of the epithelial cell marker E-cadherin at the proteins level. In addition, overexpression of miR-21 enhanced the invasiveness of HeLa and SiHa cells. These results demonstrated that miR-21 was upregulated in cervical cancer tissues and promoted cell metastasis through modulating EMT. A better understanding of the role of miR-21 and EMT may lead to the development of more effective therapies for patients with cervical cancer.

MicroRNAs Involved in Metastasis of Hepatocellular Carcinoma: Target Candidates, Functionality and Efficacy in Animal Models and Prognostic Relevance

Hepatocellular carcinoma (HCC) is responsible for the second-leading cancer-related death toll worldwide. Although sorafenib and levantinib as frontline therapy and regorafenib, cabazantinib and ramicurimab have now been approved for second-line therapy, the therapeutic benefit is in the range of only a few months with respect to prolongation of survival. Aggressiveness of HCC is mediated by metastasis. Intrahepatic metastases and distant metastasis to the lungs, lymph nodes, bones, omentum, adrenal gland and brain have been observed. Therefore, the identification of metastasis-related new targets and treatment modalities is of paramount importance. In this review, we focus on metastasis-related microRNAs (miRs) as therapeutic targets for HCC. We describe miRs which mediate or repress HCC metastasis in mouse xenograft models. We discuss 18 metastasis-promoting miRs and 35 metastasis-inhibiting miRs according to the criteria as outlined. Six of the metastasis-promoting miRs (miR-29a, -219-5p, -331-3p, 425-5p, -487a and -1247-3p) are associated with unfavourable clinical prognosis. Another set of six down-regulated miRs (miR-101, -129-3p, -137, -149, -503, and -630) correlate with a worse clinical prognosis. We discuss the corresponding metastasis-related targets as well as their potential as therapeutic modalities for treatment of HCC-related metastasis. A subset of up-regulated miRs -29a, -219-5p and -425-5p and down-regulated miRs -129-3p and -630 were evaluated in orthotopic metastasis-related models which are suitable to mimic HCC-related metastasis. Those miRNAs may represent prioritized targets emerging from our survey.

Sema4C mediates EMT inducing chemotherapeutic resistance of miR-31-3p in cervical cancer cells

Sema4C, the target of many miRNAs, is involved in EMT-mediated chemotherapeutic resistance of many malignant tumors. However, the underlying upstream regulatory mechanisms of Sema4C-induced EMT and Sema4C-mediated drug resistance are still unclear. The aim of this study was to explore the potential role of miR-31-3p/Sema4C in regulating EMT in cisplatin-resistant (CR) cervical cancer cells. High expression levels of Sema4C were more frequently found in cervical cancer tissues and were associated with poor prognosis, whereas miR-31-3p was significantly downregulated in cervical cancer tissues, which was associated with shorter disease-free and overall survival. Overexpression of miR-31-3p inhibited malignant behaviors and EMT of cervical cancer cells in vitro. Furthermore, miR-31-3p was identified to directly target Sema4C, and upregulation of miR-31-3p reversed EMT-mediated biological functions, including cisplatin resistance of Sema4C in cervical cancer cells. These results suggest that Sema4C promoted EMT-mediated cisplatin resistance in cervical cancer cells and that this effect was inhibited by overexpression of miR-31-3p. Thus, silencing Sema4C or overexpression of miR-31-3p could be a novel approach to treat drug resistance to chemotherapy in cervical cancers.

Metadherin Promotes Malignant Phenotypes And Induces Beta-Catenin Nuclear Translocation And Epithelial-Mesenchymal Transition In Gastric Cancer

Purpose

Metadherin (MTDH), as an oncogene, is associated with metastasis and poor prognosis. This study investigated MTDH expressions and development of gastric cancer (GC) cell phenotypes and the contribution of MTDH to epithelial–mesenchymal transition (EMT).

Patients and methods

MTDH expression was assayed in human GC cell lines and tumor tissue from 92 GC patients. Functional experiments were performed to characterize MTDH activity. Expressions of EMT-related proteins (vimentin and E-cadherin), phosphorylated β-catenin and β-catenin were assayed by immunohistochemistry, Western blotting, immunofluorescence, and co-immunoprecipitation, respectively.

Results

MTDH expressions were higher in GC tissue than that in gastric mucosa from the same patient. MTDH overexpression was correlated with metastasis and enhanced malignant GC phenotypes, i.e., proliferation, migration, invasiveness, and chemoresistance. MTDH overexpression was associated with expressions of vimentin, E-cadherin and cancer stem-cell biomarkers including CD44, CD133, and Oct4. MTDH complexed with β-catenin and decreased phosphorylated β-catenin levels to facilitate β-catenin translocation into the nucleus and expressions of downstream genes.

Conclusion

MTDH overexpression in GC cells is associated with EMT and development of cancer stem cell malignant phenotypes and affects the subcellular translocation of β-catenin. The results warrant investigation of the prognostic value of MTDH in GC and as a therapeutic target.

Serum miR-30d as a novel biomarker for multiple myeloma and its antitumor role in U266 cells through the targeting of the MTDH/PI3K/Akt signaling pathway

Multiple myeloma (MM) is a hematological tumor and is characterized by the infiltration of malignant clonal plasma cells (PCs) in bone marrow. MicroRNAs (miRNAs or miRs) have been reported to play an important role in the genesis and progression of MM. However, little is known about the clinical diagnostic value and biological functions of miR-30d in MM. In this study, to investigate the role of miR-30d in MM, we used reverse transcription-quantitative polymerase chain reaction quantitative (RT-qPCR) to detect the relative expression level of miR-30d in the serum of 81 patients with primary MM and 78 healthy donors (HDs). The biological functions of miR-30d were then assessed by CCK-8 assay, flow cytometric analysis of apoptosis and western blot (WB) analysis in U266 cells. Moreover, the confirmation of the target gene of miR-30d was conducted by luciferase reporter assay. Our results indicated that miR-30d expression was significantly downregulated in the serum of patients with primary MM compared with that of the HDs and that it was significantly associated with several clinical indicators of MM. Further cell functional analyses using the U266 cells revealed that miR-30d functions as a tumor suppressor gene in MM by inhibiting cell viability and promoting cell apoptosis. Moreover, miR-30d was confirmed to directly bind to the 3'UTR of its target gene, metadherin (MTDH) and inhibit the activation of the downstream PI3K/Akt signaling pathway. On the whole, the findings of this study indicate that the serum expression level of miR-30d is of great significance to the diagnosis and treatment monitoring of patients with MM. Moreover, miR-30d carries out its antitumor role in U266 cells through the inhibition of the activation of the PI3K/Akt signaling pathway by negatively regulating MTDH, which reveals its potential for use as a therapeutic target for MM.

MicroRNAs, long noncoding RNAs, and circular RNAs: potential tumor biomarkers and targets for colorectal cancer

Noncoding RNAs (ncRNAs) can be divided into microRNAs (miRNAs), long noncoding RNAs (lncRNAs), circular RNAs (circRNAs), pRNAs, and tRNAs. Traditionally, miRNAs exert their biological function mainly through the inhibition of translation via the induction of target RNA transcript degradation. lncRNAs and circRNAs were once considered to have no potential to code proteins. Here, we will review the current knowledge on ncRNAs in relation to their origins, characteristics, and functions. We will also review how ncRNAs work as competitive endogenous RNA, gene transcription and expression regulators, and RNA-binding protein sponges in colorectal cancer (CRC). Notably, except for the abovementioned mechanisms, recent advances revealed that lncRNAs can also act as the precursor of miRNAs, and a small portion of lncRNAs and circRNAs was verified to have the potential to code proteins, providing new evidence for the significance of ncRNAs in CRC tumorigenesis and development.

Identification of genes associated with SiHa cell sensitivity to paclitaxel by CRISPR-Cas9 knockout screening

Although chemotherapy has significantly improved the prognosis of patients with cervical cancer, many patients exhibit selective responses to chemotherapy. This study aimed to identify genes associated with the sensitivity of cervical cancer cells to paclitaxel. SiHa cells were transfected with lentiCRISPR (genome-scale CRISPR knockout library v.2) and then treated with paclitaxel or vehicle for 14 days. Subsequently, we screened for candidate genes whose loss resulted in sensitivity to paclitaxel. We obtained 374 candidates, some of which were consistent with those reported in previous studies, including ABCC9, IL37, EIF3C, AKT1S1, and several members of the PPP gene family (PPP1R7, PPP2R5B, PPP1R7, and PPP1R11). Importantly, our findings highlighted the newly identified genes that could provide novel insights into the mechanisms of paclitaxel sensitivity in cervical cancer. Cas9 technology provides a reliable method for the exploration of more effective combination chemotherapies for patients at the gene level.

Silencing of astrocyte elevated gene-1 inhibits proliferation and migration of melanoma cells and induces apoptosis

Melanoma is an aggressive skin malignancy with a high mortality. Astrocyte elevated gene-1 (AEG-1), a downstream target of Ras and c-Myc, has been implicated in the development of multiple tumours, but its role in melanoma remains unclear. In the present study, the role of AEG-1 in melanoma was explored through AEG-1 silencing. Our results showed that silencing AEG-1 inhibited the proliferation of melanoma cells, induced cell cycle arrest, and reduced levels of cyclin A, cyclin B, cyclin D1, cyclin E, and cyclin-dependent kinase 2. AEG-1silencing also induced apoptosis in melanoma cells and altered the levels of cleaved caspase-3, B-cell lymphoma-2 (Bcl-2) and Bcl-2 associated X protein. Moreover, silencing AEG-1 suppressed the migration and invasion of melanoma cells, reduced the expressions and activities of matrix metallopeptidase (MMP)-2 and MMP-9, and inhibited the activation of the Wnt/β-catenin signalling pathway in melanoma cells. Furthermore, in vivo experiments revealed that AEG-1 silencing inhibited the growth of melanoma xenografts in nude mice. In summary, our study demonstrates an oncogenic role of AEG-1 in melanoma and suggests that AEG-1 may serve as a potential therapeutic target in the treatment of melanoma.

Metadherin contributes to epithelial-mesenchymal transition and paclitaxel resistance induced by acidic extracellular pH in nasopharyngeal carcinoma

Paclitaxel resistance is a challenge to the treatment of nasopharyngeal carcinoma (NPC). An acidic extracellular pH (pH_e), a hallmark of solid tumors, is demonstrated to decrease the efficacy of chemotherapy. However, the precise function of acidic pH_e in mediating chemotherapy in NPC remains unknown. In the present study, acidic pH_e significantly decreased the cytotoxicity of paclitaxel in NPC cells. In addition, epithelial-mesenchymal transition (EMT)-like changes were observed in NPC cells cultured at acidic pH_e. Metadherin (MTDH), a novel oncogene, is expressed in multiple types of solid tumor, and is associated with several malignant cell characteristics, including malignant cell transformation, proliferation, angiogenesis, chemoresistance, invasion and metastasis. In the present study, MTDH expression was increased in NPC cells that had been cultured at an acidic pH_e. Furthermore, the silencing of MTDH expression reversed EMT molecular marker expression and sensitized NPC cells to paclitaxel. Taken together, the results of the present study provide evidence to support an association between acidic pH_e-induced paclitaxel resistance and MTDH-mediated EMT in NPC cells. Thus, targeting MTDH may provide a novel strategy for overcoming chemoresistance in NPC therapy.

MiR-98 inhibits malignant progression via targeting MTDH in squamous cell carcinoma of the head and neck

PURPOSE

MicroRNAs function through regulating specific target mRNA expression and then participate in the development and progression of diverse human cancers. MiR-98 shows aberrant expression and dysfunction in tumors. However, its clinical significance and exact role in squamous cell carcinoma of the head and neck (SCCHN) remain elusive.

METHODS

MiR-98 expression was examined by qRT-PCR and correlated with clinicopathological variables and prognosis in SCCHN patients. Effects of miR-98 on epithelial-mesenchymal transition (EMT) and the malignant phenotypes of SCCHN were studied. Finally, the role of target gene metadherin (MTDH) in miR-98 mediated effects were assayed.

RESULTS

Our results demonstrated that miR-98, as an endogenous inhibitor of MTDH via directly binding to its 3'-untranslated region (UTR) region, decreased significantly in SCCHN tissues. Decreased miR-98 expression was negatively correlated with T classification, clinical stage, lymph node metastasis and a shorter survival status in SCCHN patients. Loss-of-function and gain-of-function analyses confirmed that miR-98 inhibited cell proliferation, migration and invasion of SCCHN cells in vitro. Moreover, miR-98 repression led to increased MTDH expression and induced EMT alteration. Importantly, ectopic expression of MTDH partially reversed the effects caused by miR-98 overexpression.

CONCLUSIONS

Our study identifies that miR-98 serves as a suppressor in SCCHN progression via targeting oncogene MTDH.

let-7d suppresses proliferation and invasion and promotes apoptosis of meningioma by targeting AEG-1

BACKGROUND

let-7d has been indicated to act as a tumor suppressor in various cancers. However, the function and molecular mechanism of let-7d in meningioma progression have not been elucidated.

MATERIALS AND METHODS

Quantitative real-time polymerase chain reaction (qRT-PCR) was performed to detect the expression levels of let-7d and AEG-1 mRNA in meningioma tissues and cell lines. The protein level of AEG-1 was measured by Western blot analysis. MTT assay, Transwell invasion assay and flow cytometry analysis were carried out to determine the proliferation, invasion and apoptosis of IOMM-Lee and CH-157MN cells, respectively. Target gene of let-7d was verified by luciferase reporter analysis.

RESULTS

let-7d expression was downregulated, and AEG-1 expression was upregulated in meningioma tumor tissues. let-7d overexpression suppressed proliferation and invasion and induced apoptosis in IOMM-Lee and CH-157MN cells. Moreover, AEG-1 was a direct target of let-7d. Restoration of AEG-1 expression reversed let-7d-mediated suppression of the proliferation and invasion and let-7d-induced apoptosis in IOMM-Lee and CH-157MN cells.

CONCLUSION

let-7d repressed proliferation and invasion and promoted apoptosis of meningioma cells by targeting AEG-1. The present study provided a better understanding of the meningioma pathogenesis and a promising therapeutic target for meningioma patients.

Diindolylmethane and its halogenated derivatives induce protective autophagy in human prostate cancer cells via induction of the oncogenic protein AEG-1 and activation of AMP-activated protein kinase (AMPK)

3,3'-Diindolylmethane (DIM) and its synthetic halogenated derivatives 4,4'-Br₂- and 7,7'-Cl₂DIM (ring-DIMs) have recently been shown to induce protective autophagy in human prostate cancer cells. The mechanisms by which DIM and ring-DIMs induce autophagy have not been elucidated. As DIM is a mitochondrial ATP-synthase inhibitor, we hypothesized that DIM and ring-DIMs induce autophagy via alteration of intracellular AMP/ATP ratios and activation of AMP-activated protein kinase (AMPK) signaling in prostate cancer cells. We found that DIM and ring-DIMs induced autophagy was accompanied by increased autophagic vacuole formation and conversion of LC3BI to LC3BII in LNCaP and C42B human prostate cancer cells. DIM and ring-DIMs also induced AMPK, ULK-1 (unc-51-like autophagy activating kinase 1; Atg1) and acetyl-CoA carboxylase (ACC) phosphorylation in a time-dependent manner. DIM and the ring-DIMs time-dependently induced the oncogenic protein astrocyte-elevated gene 1 (AEG-1) in LNCaP and C42B cells. Downregulation of AEG-1 or AMPK inhibited DIM- and ring-DIM-induced autophagy. Pretreatment with ULK1 inhibitor MRT 67307 or siRNAs targeting either AEG-1 or AMPK potentiated the cytotoxicity of DIM and ring-DIMs. Interestingly, downregulation of AEG-1 induced senescence in cells treated with overtly cytotoxic concentrations of DIM or ring-DIMs and inhibited the onset of apoptosis in response to these compounds. In summary, we have identified a novel mechanism for DIM- and ring-DIM-induced protective autophagy, via induction of AEG-1 and subsequent activation of AMPK. Our findings could facilitate the development of novel drug therapies for prostate cancer that include selective autophagy inhibitors as adjuvants.

MTDH promotes glioma invasion through regulating miR-130b-ceRNAs

Cell invasion is crucial for high mortality and recurrence rate in glioma. Epithelial-mesenchymal transition (EMT) is an important step in cancer invasion. Metadherin (MTDH) contributes to EMT in several cancers, but the role and mechanism of MTDH in EMT-like process of glioma remain unknown. Here we demonstrate that MTDH was overexpressed in glioma tissues and cells and induced EMT-like change and invasion of glioma cells. Interestingly, MTDH could modulate the expression of a group of glioma-related miRNAs. In particular, MTDH upregulated miR-130b transcription via acting as a coactivator of NF-kB. MiR-130b promoted EMT-like change and invasion of glioma cells through targeting multiple EMT-related genes, including PTEN, PPP2CA and SMAD7. In addition, PTEN acted as the competing endogenous RNA (ceRNA) to affect PPP2CA and SMAD7 expression, and inhibited EMT-like change in glioma cells. Furthermore, miR-130b mediated EMT-like change induced by MTDH, and MTDH inhibited the expression levels of PTEN, PPP2CA and SMAD7. Taken together, we reveal a novel mechanism that MTDH induces EMT-like change and invasion of glioma via the regulation of miR-130b-ceRNAs, providing the first direct link between MTDH and miRNAs in cancer cells.

MicroRNA-202 inhibits cell proliferation, migration and invasion of glioma by directly targeting metadherin

Glioma is the most common and aggressive type of primary malignant brain tumour. Increasing evidence has revealed that microRNAs play important roles in multiple biological processes related to glioma occurrence, development, diagnosis, treatment and prognosis. MicroRNA-202 (miR-202) has been studied in several types of human cancer, whereas the biological roles of miR-202 in glioma remain unknown. The present study, aimed to investigate the expression, clinical significance and biological roles of miR-202 in glioma, as well as its underlying molecular mechanism. We found that miR-202 was significantly downregulated in glioma tissues and cell lines. Low miR-202 expression was associated with Karnofsky performance status (KPS) score and World Health Organization (WHO) grade of glioma patients. Functional assays revealed that ectopic expression of miR-202 inhibited cell proliferation, migration and invasion of glioma. In addition, metadherin (MTDH) was identified as a direct target gene of miR-202 in glioma through bioinformatic analysis, luciferase reporter assay, reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and western blotting. Furthermore, MTDH expression was upregulated and negatively correlated with miR-202 expression in clinical glioma tissues. MTDH knockdown had similar roles to miR-202 overexpression in glioma cells. Rescue experiments revealed that upregulation of MTDH reversed the suppression of glioma cell growth and metastasis by miR-202. Moreover, miR-202 impaired the PI3K/Akt and Wnt/β-catenin pathways. These results highlight the tumour-suppressive effect of miR-202 in glioma, thereby suggesting that miR-202 may be a potential therapeutic target for the treatment of patients with this malignancy.

Astrocyte-elevated gene-1 confers resistance to pemetrexed in non-small cell lung cancer by upregulating thymidylate synthase expression

Previous studies have suggested that astrocyte-elevated gene-1 (AEG-1) contributes to the mechanisms of resistance to various chemotherapeutics. In this study, we investigated whether AEG-1 expression level correlated with that of thymidylate synthase (TS), as higher TS expression is known to be associated with the resistance to pemetrexed chemotherapy in patients with advanced lung adenocarcinoma. Using pemetrexed-resistant lung adenocarcinoma PC-9 cell line, we demonstrated that transfection of AEG-1 siRNA lowered TS expression and decreased pemetrexed IC₅₀ value. In contrast, overexpression of AEG-1 was associated with increased expression of TS and higher pemetrexed IC₅₀ value. Immunohistochemical staining of clinical biopsy samples showed that patients with lower AEG-1 expression had longer overall survival time. Moreover, analysis of repeated biopsy samples revealed that an increase in the TS level from baseline to disease progression was significantly associated with the elevation of AEG-1 expression. In conclusion, our data demonstrated that TS expression might be regulated by AEG-1 and that increased expression of these proteins contributes to lung cancer disease progression and may be associated with the development of resistance to pemetrexed.

Metadherin regulates actin cytoskeletal remodeling and enhances human gastric cancer metastasis via epithelial-mesenchymal transition

Metadherin (MTDH) can be recruited to mature tight junction complexes, and it regulates mesenchymal marker protein expression in many tumors and promote cancer metastasis. This study investigated the influence of MTDH expression on gastric cancer and to elucidate the potential mechanisms by which MTDH regulates actin cytoskeletal remodeling and enhances human gastric cancer metastasis via epithelial-mesenchymal transition (EMT). Relative MTDH mRNA expression levels were assessed by quantitative real-time PCR (Q-PCR), and MTDH protein expression levels and localization were evaluated via immunohistochemical (ICH) staining. We studied the role of MTDH in cancer cell migration and invasion by modulating MTDH expression in the gastric cancer cell lines MKN45 and AGS. We also confirmed the functions of MTDH through in vivo experiments. We found that MTDH expression levels were correlated with lymph node metastasis, TNM stages and decreased OS (P=0.002, <0.001 and 0.010, respectively) in human gastric cancer and that MTDH upregulation promoted EMT in vitro. Consistent with this finding, MTDH downregulation inhibited cell migration and invasion in vitro and suppressed tumor growth and metastasis in vivo. Furthermore, MTDH knockdown regulated actin cytoskeletal remodeling and inhibited EMT. Overall, our results provide a novel role for MTDH in regulating gastric cancer metastasis.

The essential role of MTDH in the progression of HCC: a study with immunohistochemistry, TCGA, meta-analysis and in vitro investigation

Recent studies found that metadherin (MTDH) played an essential role in hepatocellular carcinoma (HCC). Nevertheless, the exact function of MTDH in the pathogenesis of HCC was unclarified. In the present study, we aimed to investigate the clinical significance of MTDH in HCC and its effect on HCC cells. Immunohistochemistry (IHC) was performed to detect MTDH expression in HCC tissues. Data from The Cancer Genome Atlas (TCGA) and ONCOMINE was obtained to examine MTDH expression in HCC and its clinical significance. Meta-analysis was conducted to assess the correlation between MTDH expression and both the prognosis (Overall Survival (OS) or Disease-free Survival (DFS)) and clinicopathological features of HCC via STATA 12.0. In vitro experiments were performed to investigate the role of MTDH in cell growth, caspase-3/7 activity and apoptosis in HCC cells. The MTDH staining was remarkably stronger in HCC tissues than in non-cancer tissues from IHC, TCGA and ONCOMINE data. Moreover, MTDH-positive expression was significantly correlated with pathological grade, distant metastasis and hepatitis B virus (HBV) infection by IHC. For meta-analysis, MTDH expression was indicative of poor OS without heterogeneity in HCC patients. Additionally, MTDH expression was correlated with high-grade histological differentiation, non-vascular invasion and metastasis in HCC. In vitro experiments revealed that MTDH could the inhibit cell growth and activate caspase-3/7 activity and apoptosis in the four HCC cell lines. In conclusion, MTDH expression may serve as a novel targeting strategy for HCC due to its clinical significance and oncogenic function in HCC cells.

LncRNA PVT1 epigenetically silences miR-195 and modulates EMT and chemoresistance in cervical cancer cells

The plasmacytoma variant translocation 1 gene (PVT1) is an oncogenic lncRNA with regulative effect on chemosensitivity in cervical cancer. However, the underlying mechanisms were not fully understood. In this study, HPV16 positive CaSki and SiHa cells were used as in vitro cell model. Knockdown of HPV16 E7 significantly inhibited PVT1 and restored miR-195 expression. PVT1 directly interacts with EZH2 and the complex anchors in the promoter region of miR-195. PVT1 overexpression resulted in increased H3K27me3 levels in the miR-195 promoter region, while PVT1 knockdown decreased H3K27me3 levels in the promoter region. In addition, PVT1 could competitively bind with miR-195. MiR-195 overexpression suppressed PVT1 expression in the cancer cells. Both PVT1 and miR-195 could inhibit paclitaxel (PTX) induced epithelial-to-mesenchymal transition (EMT) and also sensitize CaSki cells to PTX. Based on these findings, we infer that PVT1 could decrease miR-195 expression via enhancing histone H3K27me3 in the miR-195 promoter region and also via direct sponging of miR-195. In addition, the PVT1/miR-195 axis can modulate responses of the cancer cells to PTX via regulating EMT.

SU6668 modulates prostate cancer progression by downregulating MTDH/AKT signaling pathway

Prostate cancer is the second leading cause of cancer deaths among men in Western counties and has increased in incidence also in China in recent years. Although diagnosis modalities for primary prostate cancer have markedly improved, there are still no effective therapies for metastatic prostate cancer. SU6668 is an inhibitor of the tyrosine kinase activity of three angiogenic receptors VEGFR2, PDGFRβ and FGFR1. There is strong experimental evidence that SU6668 can induce growth inhibition of various primary tumors. However, the function and molecular mechanism of SU6668 in prostate cancer has not been fully elucidated. In the present study, we found that SU6668 inhibited the proliferation and invasion of prostate cancer cells. Functional studies also demonstrated that SU6668 inhibited epithelial-mesenchymal transition in DU145 and LNCap cells. After treatment with SU6668, MTDH protein, which has been reported to be significantly overexpressed in many human tumor tissues, was downregulated in DU145 and LNCap cells. siRNA-mediated silencing of MTDH in prostate cancer cells decreased their proliferation and invasive capabilities, suggesting that SU6668 may inhibit cell proliferation and invasion of prostate cancer cells partly through downstream targeting of MTDH. Mechanistic investigations showed that AKT signaling pathway was inhibited after SU6668 treatment in prostate cancer cells. Moreover, a combination of SU6668 and PI3K-AKT pathway inhibitor LY29004 resulted in increased inhibition of cell proliferation and invasion in DU145 cells. Taken together, our findings revealed that SU6668 suppressed prostate cancer progression by downregulating MTDH/AKT signaling pathway and identified a promising therapeutic strategy for prostate cancer.

Exposure to TNF‑α combined with TGF‑β induces carcinogenesis in vitro via NF-κB/Twist axis

Persistent human papilloma virus (HPV) infection induces chronic inflammation resulting in human cervical cancer. However, the mechanisms underlying carcinogenesis via chronic inflammation remain largely unclear. We investigated the role of pro-inflammatory factors in epithelial-mesenchymal transition (EMT) and cancer stem cell-like (CSCL) characteristics of HeLa cells exposed to TNF‑α with or without TGF‑β. We then determined the role of NF-κB/Twist signal axis in the pathogenesis of cervical cancer. We found that HeLa cells exposed to TNF‑α following chronic treatment with TGF‑β exhibited EMT, self-renewal and high mobility. Knockdown of NF-κBp65 inhibited NF-κB and Twist1 expression, and EMT and CSCL properties of HeLa cells following co-treatment with TNF‑α and TGF‑β. Conversely, overexpression of NF-κBp65 potentiated the above effects. However, knockdown or overexpression of Twist1 had no effect on NF-κBp65 expression, but inhibited or promoted EMT and CSCL features. Notably, overexpression of Twist1 rescued NF-κBp65 knockdown. Our results demonstrate the role of NF-κB/Twist signaling axis in which HeLa cells treated with TNF‑α following chronic exposure to TGF‑β induce EMT and CSCL properties. The NF-κB/Twist signal axis may represent an effective therapeutic target in cervical cancer.

miR-25-3p reverses epithelial-mesenchymal transition via targeting Sema4C in cisplatin-resistance cervical cancer cells

Acquisition of epithelial-mesenchymal transition (EMT) has recently been proposed as an important contributor of drug resistance in cervical cancer cells. However, the underlying mechanisms are still unclear. MicroRNAs play a crucial role in regulating EMT. The aim of this study was to explore the potential role of miR-25-3p in regulating EMT in cisplatin-resistant (CR) cervical cancer cells. To this end, we established stable CR cervical cancer cells, HeLa-CR and CaSki-CR, and investigated the function of miR-25-3p in regulating EMT. It is found that CR cervical cancer cells possessed more EMT characteristics and demonstrated higher migratory abilities and invasiveness. miR-25-3p downregulation was also seen in HeLa-CR and CaSki-CR cells. Of note, ectopic expression of miR-25-3p reversed the EMT phenotype and sensitized CR cells to cisplatin via targeting Sema4C. Furthermore, stable overexpression of miR-25-3p in HeLa-CR cells suppressed tumor growth in mice, downregulated Sema4C and Snail, and upregulated E-cadherin compared with the control group. These results suggest that miR-25-3p is an important regulator of cervical cancer EMT and chemoresistance. Thus, upregulation of miR-25-3p could be a novel approach to treat cervical cancers that are resistant to chemotherapy.

Epidermal growth factor receptor kinase substrate 8 promotes the metastasis of cervical cancer via the epithelial-mesenchymal transition

Epidermal growth factor receptor pathway substrate 8 (Eps8) has been identified as a novel substrate for epidermal growth factor receptor (EGFR) kinase and is involved in EGFR-mediated signaling pathways correlated with tumorigenesis, proliferation and metastasis in various cancer types. However, the precise role of Eps8 in cervical cancer metastasis remains to be elucidated. Immunohistochemistry revealed that Eps8 was significantly increased in cervical cancer specimens compared with squamous intraepithelial lesion and normal cervical tissues. Additionally, it was revealed that Eps8 expression not only correlated with cervical cancer progression, but also exhibited a close correlation with the epithelial-mesenchymal transition (EMT) markers, E-cadherin and vimentin. Furthermore, the present study focused predominantly on the EMT-associated role of Eps8 in the EMT, migration and invasion of cervical cancer cells. Eps8-short hairpin (sh) RNA was transfected into HeLa and SiHa cells to deplete its expression, and reverse transcription-quantitative polymerase chain reaction and western blot analyses were performed to confirm Eps8-knockdown and to investigate the influence of Eps8 on EMT markers. The present findings have revealed that Eps8 silencing led to the upregulation of the epithelial marker E-cadherin, while expression of the mesenchymal marker vimentin and the transcription factor snail was decreased at both mRNA and protein expression levels. Transwell cell migration and Matrigel invasion assays showed that downregulation of Eps8 significantly inhibited cell migration and invasion of HeLa and SiHa cells. Taken together, these results suggested that Eps8 promotes cervical cancer metastasis by orchestrating the EMT.

MiR-497 suppresses angiogenesis and metastasis of hepatocellular carcinoma by inhibiting VEGFA and AEG-1

Hepatocellular carcinoma (HCC) is a worldwide malignance and displays marked vascular abnormalities and active metastasis. MicroRNAs (miRNAs) have been shown to play important roles in regulating tumor properties in cancer, however, whether miR-497 contributes to HCC angiogenesis or metastasis remains unclear. In this study, we found that miR-497 was significantly down-regulated in HCC tissue samples and cell lines. Gain-of-function and loss-of-function studies revealed that miR-497 could repress both the pro-angiogenic and metastatic ability of HCC cells. Subsequent investigations disclosed that miR-497 directly inhibited the 3′-untranslated regions (UTRs) of vascular endothelial growth factor A (VEGFA) and astrocyte elevated gene-1 (AEG-1). Furthermore, overexpression of these targets antagonized the function of miR-497. Based on nude mouse models, we demonstrated that overexpression of miR-497 significantly repressed microvessel densities in xenograft tumors and reduced pulmonary metastasis. In conclusion, our findings indicate that miR-497 downregulation contributes to angiogenesis and metastasis in HCC.

Molecular mechanisms of cisplatin resistance in cervical cancer

Patients with advanced or recurrent cervical cancer have poor prognosis, and their 1-year survival is only 10%–20%. Chemotherapy is considered as the standard treatment for patients with advanced or recurrent cervical cancer, and cisplatin appears to treat the disease effectively. However, resistance to cisplatin may develop, thus substantially compromising the efficacy of cisplatin to treat advanced or recurrent cervical cancer. In this article, we systematically review the recent literature and summarize the recent advances in our understanding of the molecular mechanisms underlying cisplatin resistance in cervical cancer.

Metadherin regulates epithelial-mesenchymal transition in carcinoma

Metadherin (MTDH) was first identified in primary human fetal astrocytes exposed to HIV-1 in 2002 and then recognized as an important oncogene mediating tumorigenesis, progression, invasiveness, and metastasis of carcinomas. Epithelial–mesenchymal transition (EMT) is a vital process in embryonic development, organ repair, and cancer progression. MTDH and EMT have also been proved to be related to the prognosis of patients with cancers. Recent studies reveal a relationship between MTDH overexpression and EMT in some malignancies. This review highlights the overexpression of MTDH and EMT in cancers and their correlations in clinical studies. Positive correlations have been established between MTDH and mesenchymal biomarkers, and negative correlations between MTDH and epithelial biomarkers have also been established. Furthermore, experiments reveal EMT regulated by MTDH, and some signal pathways have been established. Some anticancer drugs targeting MTDH and EMT are introduced in this review. Some perspectives concerning EMT regulation by MTDH are also presented in this review.

The expression of AEG-1 and Cyclin D1 in human bladder urothelial carcinoma and their clinicopathological significance

OBJECTIVE

Astrocyte elevated gene-1 (AEG-1) and Cyclin D1 is associated with tumorigenesis and progression. The aim of this study is to investigate the expression of AEG-1 and Cyclin D1 in human bladder urothelial carcinoma (BUC) and explore their clinical and pathological significance.

METHODS

The expression of AEG-1 and Cyclin D1 protein were detected in 85 cases of human BUC and 16 cases of tumor-adjacent tissues by the immunohistochemical method.

RESULTS

The positive expression level of AEG-1 was 61.2% in human BUC which was higher than that in tumor-adjacent tissues (18.8%), P=0.002. The high expression of AEG-1 protein was correlated with the recurrence group (P=0.004). The positive rate of AEG-1 protein in superficial carcinoma group was lower than that of invasive cancer group (P=0.014). The positive expression level of Cyclin D1 was 56.5% in BUC, which was higher than that in tumor-adjacent tissues (12.5%). P=0.001. The high expression of Cyclin D1 protein was correlated with the recurrence group (P=0.024). The positive rate of Cyclin D1 protein in low grade group was lower than that of high grade group (P=0.001). The positive rate of Cyclin D1 protein in superficial carcinoma group was lower than that of invasive carcinoma group, (P=0.012). AEG-1 protein was positively correlated with Cyclin D1 protein (r=0.567, P<0.001). The log-rank test statistical analysis suggested that patients with higher AEG-1 or Cyclin D1 expression had shorter overall survival time, while patients with lower AEG-1 or Cyclin D1 expression had better survival.

CONCLUSION

Overexpression of AEG-1 and Cyclin D1 are markedly correlated with TNM stage and recurrence of BUC. Cyclin D1 are markedly correlated with grade of BUC. Detection of AEG-1 and Cyclin D1 may be helpful to evaluate prognosis and infiltrative capability of BUC.

EMT-Inducing Molecular Factors in Gynecological Cancers

Gynecologic cancers are the unregulated growth of neoplastic cells that arise in the cervix, ovaries, fallopian tubes, uterus, vagina, and vulva. Although gynecologic cancers are characterized by different signs and symptoms, studies have shown that they share common risk factors, such as smoking, obesity, age, exposure to certain chemicals, infection with human immunodeficiency virus (HIV), and infection with human papilloma virus (HPV). Despite recent advancements in the preventative, diagnostic, and therapeutic interventions for gynecologic cancers, many patients still die as a result of metastasis and recurrence. Since mounting evidence indicates that the epithelial-mesenchymal transition (EMT) process plays an essential role in metastatic relapse of cancer, understanding the molecular aberrations responsible for the EMT and its underlying signaling should be given high priority in order to reduce cancer morbidity and mortality.

Long non-coding RNA Linc00152 is involved in cell cycle arrest, apoptosis, epithelial to mesenchymal transition, cell migration and invasion in gastric cancer

Gastric cancer remains a serious threat to public health with high incidence and mortality worldwide. Accumulating evidence demonstrates that long non-coding RNAs (lncRNAs) play important roles in regulating gene expression and are involved in various pathological processes, including gastric cancer. To investigate the possible role of dysregulated lncRNAs in gastric cancer development, we performed lncRNA microarray and identified 3141 significantly differentially expressed lncRNAs in gastric cancer tissues. Next, some of deregulated lncRNAs were validated among about 60 paired gastric cancer specimens such as Linc00261, DKFZP434K028, RPL34-AS1, H19, HOTAIR and Linc00152. Our results found that the decline of DKFZP434K028 and RPL34-AS1, and the increased expression of Linc00152 positively correlated with larger tumor size. The high expression levels of HOTAIR were associated with lymphatic metastasis and poor differentiation. Since the biological roles of Linc00152 are largely unknown in gastric cancer pathogenesis, we assessed its functions by silencing its up-regulation in gastric cancer cells. We found that Linc00152 knockdown could inhibit cell proliferation and colony formation, promote cell cycle arrest at G1 phase, trigger late apoptosis, reduce the epithelial to mesenchymal transition (EMT) program, and suppress cell migration and invasion. Taken together, we delineate the gastric cancer lncRNA signature and demonstrate the oncogenic functions of Linc00152. These findings may have implications for developing lncRNA-based biomarkers for diagnosis and therapeutics for gastric cancer.

Epigenetic Activation of TWIST1 by MTDH Promotes Cancer Stem-like Cell Traits in Breast Cancer

Cancer stem-like cells (CSC) are a cell subpopulation that can reinitiate tumors, resist chemotherapy, and give rise to metastases. Metadherin (MTDH) contributes widely to tumor growth, drug resistance, relapse, and metastasis, but its molecular mechanisms of action are not well understood. Here, we report that MTDH drives CSC expansion by promoting the expression of TWIST1, a transcription factor critical for cancer cell stemness and metastasis. MTDH activates TWIST1 expression indirectly by facilitating histone H3 acetylation on the TWIST1 promoter, a process mediated by the histone acetyltransferase CBP. Mechanistic investigations showed that MTDH interacts with CBP and prevents its ubiquitin-mediated degradation, licensing its transcriptional activation of TWIST1. In clinical specimens of breast cancer, MTDH expression correlates positively with TWIST1 expression and CSC abundance. Overall, our work revealed that MTDH promotes CSC accumulation and breast tumorigenicity by regulating TWIST1, deepening the understanding of MTDH function in cancer.

TALEN-mediated Nanog disruption results in less invasiveness, more chemosensitivity and reversal of EMT in Hela cells

Emerging evidence suggests that Nanog is involved in cervical tumorigenesis. However, the regulating role of Nanog in tumorigenesis and chemosensitivity are still poorly understood. In this study, Nanog was disrupted by transcription activatorlike effector nucleases (TALEN) in Hela cells and its expression was significantly decreased in a single-cell derived sub-clone with biallelic mutations. The disruption of Nanog not only induced down regulation of some other core transcription factor genes for cell self-renewal, such as Oct4, Sox2 and FoxD3, but also led to the down regulation of some mesenchymal representative genes, vimentin and N-adherin, and up regulation of the epithelial gene, E-cadherin. In addition, the invasiveness and clonogenicity of the Hela cells were obviously affected, and surprisingly their sensitivities to anti-cancer drugs were also significantly increased in vitro. After Xenograft into nude mice, the growth volumes of the neoplasms from the Nanog disrupted Hela cells were significantly smaller compared with those from wild type ones. In conclusion, these results suggest that disruption of Nanog may reverse the status of epithelial-mesenchymal transition, which is critical in tumorigenesis, and alleviate chemoresistance, as well as their invasiveness, in cervical cancer cells.

MicroRNA-217 functions as a prognosis predictor and inhibits colorectal cancer cell proliferation and invasion via an AEG-1 dependent mechanism

Background

Recent studies have indicated the possible function of miR-217 in tumorigenesis. However, the roles of miR-217 in colorectal cancer (CRC) are still largely unknown.

Methods

We examined the expression of miR-217 and AEG-1 in 50 CRC tissues and the corresponding noncancerous tissues by qRT-PCR. The clinical significance of miR-217 was analyzed. CRC cell lines with miR-217 upregulation and AEG-1 silencing were established and the effects on tumor growth in vitro and in vivo were assessed. Dual-luciferase reporter gene assays were also performed to investigate the interaction between miR-217 and AEG-1.

Results

Our data demonstrated that miR-217 was significantly downregulated in 50 pairs of colorectal cancer tissues. MiR-217 expression levels were closely correlated with tumor differentiation. Moreover, decreased miR-217 expression was also associated with shorter overall survival of CRC patients. MiR-217 overexpression significantly inhibited proliferation, colony formation and invasiveness of CRC cells by promoting apoptosis and G0/G1 phase arrest. Interestingly, ectopic miR-217 expression decreased AEG-1 expression and repressed luciferase reporter activity associated with the AEG-1 3′-untranslated region (UTR). AEG-1 silencing resulted in similar biological behavior changes to those associated with miR-217 overexpression. Finally, in a nude mouse xenografted tumor model, miR-217 overexpression significantly suppressed CRC cell growth.

Conclusions

Our findings suggest that miR-217 has considerable value as a prognostic marker and potential therapeutic target in CRC.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-015-1438-z) contains supplementary material, which is available to authorized users.

Long non-coding RNAs in gastric cancer: versatile mechanisms and potential for clinical translation

Gastric cancer (GC) remains a serious threat to many people, representing the second leading cause of cancer-related death worldwide. The lack of early diagnostic biomarkers, effective prognostic indicators and therapeutic targets all account for the poor prognosis of GC. Therefore, the identification of novel molecular biomarkers for early diagnosis, therapeutic response, and prognosis are urgently needed. High-throughput sequencing has identified a large number of transcribed long non-coding RNAs (lncRNAs) throughout the human genome. Accumulating evidence demonstrates that these lncRNAs play multiple roles in regulating gene expression at the transcriptional, post-transcriptional, and epigenetic levels. Aberrant expression of lncRNAs occurs in various pathological processes, including GC. Many dysregulated lncRNAs in GC have been significantly associated with a larger tumor size, higher degree of tumor invasion, lymph node and distant metastasis, and poorer survival outcome. In this review, we will provide an overview of the pathogenesis of GC, the characteristics and regulatory functions of lncRNAs, and the versatile mechanisms of lncRNAs in GC development, as well as evaluate the translational potential of lncRNAs as novel diagnostic and prognostic biomarkers and therapeutic targets in GC.