MicroRNA-498 inhibits the proliferation, migration and invasion of gastric cancer through targeting BMI-1 and suppressing AKT pathway

miRNA/epithelial-mesenchymal axis (EMT) axis as a key player in cancer progression and metastasis: A focus on gastric and bladder cancers

The metastasis a major hallmark of tumors that its significant is not only related to the basic research, but clinical investigations have revealed that majority of cancer deaths are due to the metastasis. The metastasis of tumor cells is significantly increased due to EMT mechanism and therefore, inhibition of EMT can reduce biological behaviors of tumor cells and improve the survival rate of patients. One of the gaps related to cancer metastasis is lack of specific focus on the EMT regulation in certain types of tumor cells. The gastric and bladder cancers are considered as two main reasons of death among patients in clinical level. Herein, the role of EMT in regulation of their progression is evaluated with a focus on the function of miRNAs. The inhibition/induction of EMT in these cancers and their ability in modulation of EMT-related factors including ZEB1/2 proteins, TGF-β, Snail and cadherin proteins are discussed. Moreover, lncRNAs and circRNAs in crosstalk of miRNA/EMT regulation in these tumors are discussed and final impact on cancer metastasis and response of tumor cells to the chemotherapy is evaluated. Moreover, the impact of miRNAs transferred by exosomes in regulation of EMT in these cancers are discussed.

Bmi-1: A master regulator of head and neck cancer stemness

Head and neck cancers are composed of a diverse group of malignancies, many of which exhibit an unacceptably low patient survival, high morbidity and poor treatment outcomes. The cancer stem cell (CSC) hypothesis provides an explanation for the substantial patient morbidity associated with treatment resistance and the high frequency of tumor recurrence/metastasis. Stem cells are a unique population of cells capable of recapitulating a heterogenous organ from a single cell, due to their capacity to self-renew and differentiate into progenitor cells. CSCs share these attributes, in addition to playing a pivotal role in cancer initiation and progression by means of their high tumorigenic potential. CSCs constitute only a small fraction of tumor cells but play a major role in tumor initiation and therapeutic evasion. The shift towards stem-like phenotype fuels many malignant features of a cancer cell and mediates resistance to conventional chemotherapy. Bmi-1 is a master regulator of stem cell self-renewal as part of the polycomb repressive complex 1 (PRC1) and has emerged as a prominent player in cancer stem cell biology. Bmi-1 expression is upregulated in CSCs, which is augmented by tumor-promoting factors and various conventional chemotherapies. Bmi-1⁺ CSCs mediate chemoresistance and metastasis. On the other hand, inhibiting Bmi-1 rescinds CSC function and re-sensitizes cancer cells to chemotherapy. Therefore, elucidating the functional role of Bmi-1 in CSC-mediated cancer progression may unveil an attractive target for mechanism-based, developmental therapeutics. In this review, we discuss the parallels in the role of Bmi-1 in stem cell biology of health and disease and explore how this can be leveraged to advance clinical treatment strategies for head and neck cancer.

MicroRNA-429 Regulates Invasion and Migration of Multiple Myeloma Cells via Bmi1/AKT Pathway

Background: miR-429-mediated progression of multiple myeloma (MM) was studied through mediating B cell-specific Moloney murine leukemia virus integration site 1 (Bmi1)/protein kinase B (AKT) pathway. Methods: miRNA or siRNA was delivered into MM cell lines to alter cellular proliferation, apoptosis, invasion and migration. Measurements of miR-429 and Bmi1 levels were performed. AKT and p-AKT expression change was measured after regulating miR-429. The interaction between miR-429 and Bmi1 was analyzed. Results: miR-429 elevation disrupted proliferation, anti-apoptosis, migration and invasion properties of MM cells, and inactivated AKT pathway. Bmi1 was a targeting partner of miR-429, which was highly expressed in MM. Bmi1 knockdown phenotyped the effects of overexpressed miR-429 on MM cells. AKT agonist SC70 reversed miR-429-regulated inhibition of MM cell growth. Conclusion: miR-429 suppresses the activation of Bmi1/AKT pathway to down-regulate the malignant functions of MM cells.

The Crucial Roles of Bmi-1 in Cancer: Implications in Pathogenesis, Metastasis, Drug Resistance, and Targeted Therapies

B-cell-specific Moloney murine leukemia virus integration region 1 (Bmi-1, also known as RNF51 or PCGF4) is one of the important members of the PcG gene family, and is involved in regulating cell proliferation, differentiation and senescence, and maintaining the self-renewal of stem cells. Many studies in recent years have emphasized the role of Bmi-1 in the occurrence and development of tumors. In fact, Bmi-1 has multiple functions in cancer biology and is closely related to many classical molecules, including Akt, c-MYC, Pten, etc. This review summarizes the regulatory mechanisms of Bmi-1 in multiple pathways, and the interaction of Bmi-1 with noncoding RNAs. In particular, we focus on the pathological processes of Bmi-1 in cancer, and explore the clinical relevance of Bmi-1 in cancer biomarkers and prognosis, as well as its implications for chemoresistance and radioresistance. In conclusion, we summarize the role of Bmi-1 in tumor progression, reveal the pathophysiological process and molecular mechanism of Bmi-1 in tumors, and provide useful information for tumor diagnosis, treatment, and prognosis.

CEACAM5 targeted by miR-498 promotes cell proliferation, migration and epithelial to mesenchymal transition in gastric cancer

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CEACAM5 was upregulated in GC tissues and cells.

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CEACAM5 knockdown repressed GC cell migration, proliferation, and EMT.

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Knockdown of CEACAM5 suppressed the growth of GC cells in mice with transplanted tumor.

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CEACAM5 was predicted as a miR-498 target.

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MiR-498 reduced GC cell migration, proliferation, and EMT by inhibiting CEACAM5.

Objective

Recent studies have shown that carcinoembryonic antigen-related cell adhesion molecule 5 (CEACAM5) may serve as an independent predictor of advanced gastric cancer (GC). The purpose of this research is to explore the patterns of expression, functions, and upstream regulatory pathway of CEACAM5 in GC.

Methods

The levels of miR-498 and CEACAM5 expression in GC cells and tissues were measured via qRT-PCR. Wound-healing, CCK-8, and western blotting experiments were conducted for the evaluation of GC cell migration, proliferation, and epithelial-mesenchymal transition (EMT), respectively. The targeting relationship between miR-498 and CEACAM5 was validated via pull-down and luciferase reporter assays. Xenograft tumor mouse models were established to observe CEACAM5’s influence on the growth of tumors in vivo.

Results

Elevated levels of CEACAM5 were detected among the GC cells and tissues. The results of the in vitro experiments revealed that the knockdown of CEACAM5 in GC cells significantly inhibited their proliferation, migration, and EMT. Moreover, CEACAM5 inhibition effectively hampered GC cell growth within the nude mice. Moreover, miR-498 directly targeted CEACAM5. MiR-498 downregulation had been observed among the cells and tissues of GC. The stimulation of GC cell proliferation, migration, and EMT, which had been engendered by CEACAM5 overexpression, was reversible through the overexpression of miR-498.

Conclusion

The outcomes of this research suggest that miR-498 is capable of repressing the proliferation, migration, and EMT of GC cells through CEACAM5 downregulation.

Circ_0000658 knockdown inhibits epithelial-mesenchymal transition in bladder cancer via miR-498-induced HMGA2 downregulation

BACKGROUND

Epithelial-mesenchymal transition (EMT) has been associated with the angiogenesis and oncogenic phenotypes of multiple malignant tumors including bladder cancer (BCa). Circular RNAs (circRNAs) are recognized as crucial regulators in the EMT. This study aims to illustrate the possible role of circular RNA_0000658 (circ_0000658) in BCa and the underlying molecular mechanism.

METHODS

The expression of circ_0000658, microRNA (miR)-498, and high mobility group AT-hook 2 (HMGA2) was assessed in cancer and adjacent normal tissue collected from BCa patients and human BCa cell lines (MGH-U3, T24, 5637 and SW780). BCa cells were transduced with a series of overexpression or shRNA plasmids to clarify the function of circ_0000658 and miR-498 on the oncogenic phenotypes and EMT of BCa cells. Further, we established nude mice xenografted with BCa cells to validate the roles of circ_0000658 on tumor growth in vivo.

RESULTS

Circ_0000658 was highly expressed in BCa tissue samples and cell lines, which indicated a poor prognosis of BCa patients. Circ_0000658 competitively bound to miR-498 and thus restricted miR-498 expression. Meanwhile, circ_0000658 weakened the binding of miR-498 to the target gene HMGA2 and upregulated the HMGA2 expression. Circ_0000658 elevation or miR-498 knockdown augmented oncogenic phenotypes and EMT of BCa cells, corresponding to a reduction in the expression of β-catenin and E-cadherin as well as an increase in the expression of N-cadherin, Slug, Snail, ZEB1 and Twist. Inhibition of HMGA2 reversed the effects of circ_0000658 overexpression on tumor growth in vivo.

CONCLUSION

Altogether, our study uncovered the tumor-promoting role of circ_0000658 in BCa via the miR-498/HMGA2 axis.

RETRACTED: MicroRNA-498 disturbs the occurrence and aggression of colon cancer through targeting MDM2 to mediate PPARγ ubiquitination

This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). This article has been retracted at the request of the Editor-in-Chief. Concern was raised about the reliability of this article that shares several characteristics with other articles in the eyebrow family of publications, tabulated here (https://docs.google.com/spreadsheets/d/149EjFXVxpwkBXYJOnOHb6RhAqT4a2llhj9LM60MBffM/edit#gid=0). In addition, Fig. 5A appears to show a digital composition of xenografted tumors. The journal requested the corresponding author comment on these concerns and provide the raw data. However the authors were not able to satisfactorily fulfil this request and therefore the Editor-in-Chief decided to retract the article.

Vitamin D modulation and microRNAs in gastric cancer: prognostic and therapeutic role

Gastric adenocarcinoma arises after a complex interaction between the host and environmental factors. Tumor location and TNM are the tools that currently guide treatment decisions. Surgery is the only curative treatment, but relapse is common. After relapse or advanced staged disease survival is poor and systemic treatment has modestly improved survival. An association between sun exposure, vitamin D status and gastric cancer (GC) incidence and mortality has been reported. The molecular differences of the histological subtypes and the new molecular classifications account for the great heterogeneity of this disease and are the basis for the discovery of new therapeutic targets. New prognostic and predictive factors are essential and microRNAs (miRNAs) are endogenous small non-coding RNA molecules with a great potential for diagnosis, prognosis and treatment of cancer. There are hundreds of miRNAs with altered expression in tumor gastric tissue when compared to normal gastric tissue. Many of these miRNAs are associated with clinicopathological variables and survival in patients with GC. Furthermore, the expression of some of these miRNAs with prognostic importance in CG is influenced by vitamin D and others are mediators of some of the actions of this vitamin. This review aims to update the evidence on several miRNAs with prognostic value and therapeutic potential in GC, whose expression may be influenced by vitamin D or may regulate vitamin D signaling.

LncRNA HOTAIRM1 knockdown inhibits cell glycolysis metabolism and tumor progression by miR-498/ABCE1 axis in non-small cell lung cancer

BACKGROUND

Non-small cell lung cancer (NSCLC) is a major contributor of cancer-related mortality. Long non-coding RNAs (lncRNAs) are indicated to participate in the pathogenesis of NSCLC.

OBJECTIVE

In this research, the effects of lncRNA HOXA transcript antisense RNA, myeloid-specific 1 (HOTAIRM1) on NSCLC progression and underlying mechanism were revealed.

METHODS

The expression levels of HOTAIRM1 and microRNA-498 (miR-498) were detected by quantitative real time polymerase chain reaction (qRT-PCR) in NSCLC tissues, cells or exosomes. The protein expression of CD63, CD81, hexokinase 2 (HK2) and ATP binding cassette subfamily E member 1 (ABCE1) was determined by western blot. Cell viability, apoptosis, migration and invasion were investigated by cell counting kit-8 (CCK-8), flow cytometry, transwell migration and invasion assays, respectively. Cell glycolysis metabolism was revealed by glucose uptake and lactate production assays and western blot analysis. The binding relationship between miR-498 and HOTAIRM1 or ABCE1 was predicted by DIANA-LncBase v2 and starBase online database, and identified by dual-luciferase reporter assay. The effects of HOTAIRM1 on NSCLC growth in vivo were revealed by in vivo tumor formation assay.

RESULTS

HOTAIRM1 expression was dramatically upregulated, whereas miR-498 expression was significantly downregulated in NSCLC tissues cells or exosomes as compared to control groups. Mechanistically, HOTAIRM1 knockdown repressed cell viability, migration, invasion and glycolysis metabolism, whereas induced cell apoptosis in NSCLC; however, miR-498 inhibitor hindered these effects. Functionally, HOTAIRM1 functioned as a sponge of miR-498 and miR-498 targeted ABCE1. In addition, HOTAIRM1 silencing inhibited NSCLC growth in vivo by downregulating ABCE1 and upregulating miR-498 expression.

CONCLUSIONS

HOTAIRM1 knockdown repressed cell glycolysis metabolism and tumor development by reducing ABCE1 expression through sponging miR-498 in NSCLC, which provided a theoretical basis for further studying NSCLC progression.

Critical review of Epstein-Barr virus microRNAs relation with EBV-associated gastric cancer

Epstein-Barr virus (EBV)-associated gastric cancer (EBVaGC) is regarded as the most prevalent malignant tumor triggered by EBV infection. In recent years, increasing attention has been considered to recognize more about the disease process's exact mechanisms. There is accumulating evidence that showing epigenetic modifications play critical roles in the EBVaGC pathogenesis. MicroRNAs (miRNAs), as critical epigenetic modulators, are single-strand short noncoding RNA (length ~ <200 bp), which regulate gene expression through binding to the 3'-untranslated region (3'-UTR) of target RNA transcripts and either degrade or repress their activities. In the latest research on EBV, it was found that this virus could encode miRNAs. Mechanistically, EBV-encoded miRNAs are involved in carcinogenesis and the progression of EBV-associated malignancies. Moreover, these miRNAs implicated in immune evasion, identification of pattern recognition receptors, regulation of lymphocyte activation and lethality, modulation of infected host cell antigen, maintain of EBV infection status, promotion of cell proliferation, invasion and migration, and reduction of apoptosis. As good news, not only has recent data demonstrated the crucial function of EBV-encoded miRNAs in the pathogenesis of EBVaGC, but it has also been revealed that aberrant expression of exosomal miRNAs in EBVaGC has made them biomarkers for detection of EBVaGC. Regarding these substantial characterizes, the critical role of EBV-encoded miRNAs has been a hot topic in research. In this review, we will focus on the multiple mechanisms involved in EBVaGC caused by EBV-encoded miRNAs and briefly discuss their potential application in the clinic as a diagnostic biomarker.

MicroRNA-489-3p plays a significant role in congenital hypothyroidism through regulating neuronal cell apoptosis via targeting translationally controlled tumor protein 1

Accumulating reports have indicated that congenital hypothyroidism (CH) is an endocrine disorder caused by underdeveloped thyroid gland or thyroid dyshormonogenesis. It has been also reported that certain microRNAs (miRNAs) may exert protective effects against the development of CH. However, whether miR-489-3p regulates CH progression remains unclear. The aim of the present study was to investigate the effects of miR-489-3p on CH and elucidate the underlying mechanisms. Therefore, Sprague Dawley rats were injected with propylthiouracil (50 mg/day) to establish a CH model. Reverse transcription-quantitative PCR (RT-qPCR) assay demonstrated that miR-489-3p was upregulated in the hippocampal tissues of CH rats. Furthermore, the TargetScan software was employed to predict the target gene of miR-489-3p, and a dual luciferase reporter assay revealed that translationally controlled tumor protein 1 (TPT1) was directly targeted by miR-489-3p. Additionally, RT-qPCR and western blot assays suggested that TPT1 was markedly downregulated in the hippocampal tissues of CH rats compared with control rats. In addition, inhibitor control, miR-489-3p inhibitor, control-shRNA or TPT1-shRNA were injected into CH rats. The results of the open-field and forced swimming tests revealed that miR-489-3p inhibitor notably improved the behavior of CH rats. Flow cytometry was applied to explore the effects of miR-489-3p inhibitor on neuronal cell apoptosis, and the findings indicated that miR-489-3p inhibitor attenuated CH-induced neuronal cell apoptosis, whereas these effects were reversed by treatment with miR-489-3p inhibitor and TPT1-shRNA. Finally, the function of miR-489-3p in neuronal cells was investigated in vitro. Neuronal cell viability, apoptosis and the expression of apoptosis-related proteins were determined using MTT assay, flow cytometry and western blot analysis, respectively. The results demonstrated that miR-489-3p inhibitor enhanced cell viability, suppressed apoptosis and upregulated Pim-3, phosphorylated (p)-Bad (Ser112) and Bcl-xL expression. Rescue experiments indicated that these effects were reversed following silencing of TPT1. Taken together, the findings of the present study demonstrated that miR-489-3p inhibitor could relieve CH-induced neurological damage through regulating TPT1 expression.

LINC01255 combined with BMI1 to regulate human mesenchymal stromal senescence and acute myeloid leukemia cell proliferation through repressing transcription of MCP-1

BACKGROUND

Long non-coding RNAs (lncRNAs) govern fundamental biochemical and cellular biology processes, for example, participate in chromatin remodeling, imprinting, splicing, transcriptional regulation and translation. Dysregulation of lncRNA expression is act as a feature of various diseases and cancers, including hematopoietic malignancies. However, the clinical relevance of myelodysplastic syndrome (MDS) and acute myeloid leukemia preceded by MDS (MDS-AML) requires further research. Recently, lncRNAs have been demonstrated, which play an important role in hematopoiesis, thus, to further finding more functional lncRNA seemed particularly important.

METHODS

Western blotting, real-time PCR, RNA-pulldown, RIP (RNA immunoprecipitation), Chromatin immunoprecipitation (ChIP), cellular compartments extraction assays, SA-β-gal staining, lentivirus transfection, cell viability assay and cell proliferation assays were used to examine the relationship between lncRNA LINC01255 and its regulation of p53-p21 pathway in human mesenchymal stromal and acute myeloid leukemia cells.

RESULTS

LncRNA LINC01255 is highly expressed in bone marrow cells of AML patients, CD34+ cells of MDS-AML patients and AML cell lines and the higher expression of LINC01255 is associated with poor survival rate of AML patients. LINC01255 can interact with BMI1 and repress the transcription of MCP-1 to active p53-p21 pathway, thus inhibiting the senescence of human mesenchymal stromal and proliferation of acute myeloid leukemia cell.

CONCLUSIONS

We discovered a novel functional lncRNA LINC01255, which can regulate the senescence of human mesenchymal stromal and the proliferation of acute myeloid leukemia cell through inhibiting the transcription of MCP-1.

MicroRNA in Gastric Cancer Development: Mechanisms and Biomarkers

Gastric cancer (GC) is one of the most common and difficult diseases to treat. The study of signaling pathway regulation by microRNA provides information on the mechanisms of GC development and is the basis for biomarker creation. In this study, a circuit of microRNA interactions with signaling pathways was constructed. The microRNAs, associated with metastasis and chemoresistance, are described. In most cases, microRNAs in GC regulate the Wnt/β-catenin, PI3K/AKT/mTOR, RAS/RAF/ERK/MAPK, NF-kB, TGF-β, and JAK/STAT pathways. Part of the microRNA acts on several target genes that function in different pathways. This often leads to an intensification of the induced processes. MicroRNAs have also been described that have the opposite effect on different pathways, causing different functional consequences. By acting on several target genes, or genes associated with several pathways, microRNAs can function in a signaling network. MicroRNAs associated with metastasis most often interact with the Wnt/β-catenin pathway. MicroRNAs affecting chemoresistance, in most cases, affect the regulators of apoptosis and are associated with the PI3K/AKT/mTOR pathway. The characteristics of microRNAs proposed as candidates for GC biomarkers were analyzed. The currently developed diagnostic and prognostic panels of microRNAs are also considered.