MicroRNA miR-302 inhibits the tumorigenicity of endometrial cancer cells by suppression of Cyclin D1 and CDK1

A novel role for aspirin in enhancing the reprogramming function of miR-302/367 cluster and breast tumor suppression

Recent studies have provided evidence for tumor suppressive function of the embryonic stem cell-specific miR-302/367 cluster through induction of a reprogramming process. Aspirin has been found to induce reprogramming factors of mesenchymal-to-epithelial transition in breast cancer cells. Therefore, we aimed to investigate whether overexpression of miR-302/367 cluster and aspirin treatment cooperate in the induction of reprogramming and tumor suppression in breast cancer cells. MDA-MB-231 and SK-BR-3 human breast cancer cell lines were transfected with a miR-302/367 expressing vector and treated with aspirin. The cells were evaluated for indices of apoptosis, proliferation, migration, and invasion. In both cell lines, treatment of miR-302/367-transfected cells with aspirin upregulated expression of some main pluripotency factors such as OCT4, SOX2, NANOG, and KLF4, and downregulated expression of some invasion and angiogenesis markers at gene and protein levels. Aspirin increased the apoptotic rate in both cell lines transfected with miR-302/367. Both miR-302/367 and aspirin upregulated the expression of FOXD3 protein which is a known inducer of OCT4 and NANOG. Our results demonstrate that aspirin can enhance miR-302/367-induced reprogramming of breast cancer cells possibly through upregulation of FOXD3 expression. This can further augment the reversal of epithelial-mesenchymal transition and inhibits migration, invasion, and angiogenic signaling in breast cancer cells reprogrammed by miR-302/367. Therefore, aspirin may serve as a useful adjuvant for reprogramming of cancer cells.

Comprehensive Analysis of the Control of Cancer Stem Cell Characteristics in Endometrial Cancer by Network Analysis

Background

Cancer stem cells play an important role in endometrial cancer (EC). It is closely related to self-renewal and therapeutic resistance of EC.

Methods

In this study, WGCNA (weighted gene coexpression network analysis) was used to analyze the relationship between genes and clinical features. We also performed immune cell infiltration analysis of a key module by using ImmuCellAI (Immune Cell Abundance Identifier). Then, key genes were verified in the GEO database. Finally, causal relationship analysis and protein-protein interaction analysis were performed in DisNor tool and STRING.

Result

The mRNA expression-based stemness index (mRNAsi) is significantly lower in normal tissues and is significantly higher in individuals with stage IV or high-grade cancer and those who are obese or postmenopausal. Nineteen key genes (ORC6, C1orf112, RAD54L, SGO2, BUB1, PLK4, KIF18B, BUB1B, TTK, NCAPG, XRCC2, CENPF, KIF15, RACGAP1, ARHGAP11A, TPX2, KIF14, KIF4A, and NCAPH) that were enriched mainly in terms related to the cell cycle and DNA replication were selected by weighted gene coexpression network analysis (WGCNA). Based on the key modules, the numbers of NKT cells, NK cells, and neutrophils in the normal group were significantly higher than those in the cancer group. PLK1, CDK1, and MAD2L1, which were correlated with upstream genes, may be an regulated upstream of key genes.

Conclusion

PLK1, CDK1, and MAD2L1 which were strongly correlated with upstream genes may be a regulated upstream of key genes.

CDK1 serves as a novel therapeutic target for endometrioid endometrial cancer

Background: Endometrial cancer (EC) is one of the most common and prevalent gynecologic malignancies worldwide. The aim of this study was to identify a novel therapeutic target for endometrioid endometrial cancer.

Materials and Methods: Bioinformatic analysis was performed and CDK1 was screen out as one of the hub genes in the pathogenesis of EC. Immunohistochemistry was used to verify the expression of CDK1 in endometrial cancer tissue. Cell viability and colony formation were used to study the effects of CDK1 on the proliferation and colony formation of endometrial cancer cells in vitro. Apoptosis and cell cycle assays were used to elucidate the mechanism of CDK1 affecting cell proliferation. Tumor xenograft transplantation assay was performed to show the effects of CDK1 on the growth of endometrial cancer cells in vivo.

Results: CDK1 was over expressed in endometrioid endometrial cancer, and accumulation of cytoplasmic CDK1 was associated with histological grade of EC. CDK1 promoted endometrial cancer cell growth and colony formation in vitro. The inhibition of CDK1 activity induced cell apoptosis and caused G2/M phase arrest of cell cycle in endometrial cancer cells. The inhibition of CDK1 activity also inhibited endometrial cancer growth in xenograft models.

Conclusion: CDK1 was involved in the pathogenesis of endometrioid endometrial cancer and provided a novel therapeutic target for endometrioid endometrial cancer.

Down-regulation of MALAT1 aggravates polycystic ovary syndrome by regulating MiR-302d-3p-mediated leukemia inhibitory factor activity

AIMS

Accumulating evidence have shown the important roles of long noncoding RNA (lncRNA) in controlling different diseases. In the present study, we tried to explore the role which lncRNA MALAT1 plays in polycystic ovary syndrome (PCOS) with the involvement of microRNA-302d-3p (miR-302d-3p) and leukemia inhibitory factor (LIF).

METHODS

A PCOS rat model was established and characterized, followed by treatment with si-MALAT1, oe-MALAT1, miR-302d-3p mimic, or miR-302d-3p inhibitor constructs. Serum hormonal levels were detected to evaluate endocrine conditions. The effect of MALAT1 and miR-302d-3p on activities of ovarian granulosa cells was assessed, as well as the involvement of LIF.

RESULTS

MALAT1 expression was shown to be downregulated in ovarian tissue of PCOS rats. Overexpression of MALAT1 in vitro promoted proliferation and inhibited apoptosis of ovarian granulosa cells. Overexpression of MALAT1 in vivo reduced the ovarian tissue injury and endocrine disorders accompanied with decreased level of FSH and elevated serum levels of E2, T, and LH in the PCOS rat. Overexpression of MALAT1 also promoted the expression of LIF, which could be reversed by overexpression of miR-302d-3p, indicating that MALAT1 up-regulated the expression of LIF via miR-302d-3p. Furthermore, overexpression of MALAT1 reduced endocrine disorders and ovarian tissue damage via the miR-302d-3p/LIF axis.

CONCLUSION

Our study highlighted that MALAT1 plays a protective role in reducing ovarian tissue damage and endocrine disorder in PCOS by regulating the miR-302d-3p/LIF axis.

RACK1 promotes miR-302b/c/d-3p expression and inhibits CCNO expression to induce cell apoptosis in cervical squamous cell carcinoma

Background

Cervical squamous cell carcinoma (CSCC) is one of the main causes of cancer-related deaths in women worldwide. The present study was conducted with the main objective of determining the potential role of receptor for activated protein kinase C1 (RACK1) in CSCC through regulation of microRNA (miR)-302b/c/d-3p and Cyclin O (CCNO).

Methods

The expression of RACK1, miR-302b/c/d-3p and CCNO in CSCC tissues and cells was measured by RT-qPCR and Western blot analysis. The interaction among RACK1, miR-302b/c/d-3p, and CCNO was determined by dual luciferase reporter assay. Subsequently, effects of RACK1, miR-302b/c/d-3p and CCNO on CSCC cell cycle entry, proliferation and apoptosis were investigated with the use of flow cytometry, EdU, and TUNEL assays. Furthermore, mouse xenograft model of CSCC cells was established to verify the function of RACK1 in vivo.

Results

RACK1 and miR-302b/c/d-3p were down-regulated and CCNO was overexpressed in CSCC. CCNO was identified as the target of miR-302b/c/d-3p. Importantly, overexpressed miR-302b-3p, miR-302c-3p or miR-302d-3p or RACK1 enhanced the apoptosis and suppressed the proliferation of CSCC cells in vitro, while inhibiting tumor growth in vivo by targeting CCNO.

Conclusions

On all accounts, overexpressed RACK1 could dampen the progression of CSCC through miR-302b/c/d-3p-mediated CCNO inhibition.

Role of miR-302/367 cluster in human physiology and pathophysiology

MicroRNAs (miRNAs) are small non-coding RNAs that negatively regulate target mRNAs at the post-transcriptional level. Increasing evidence shows the involvement of miRNAs in diverse biological processes. miR-302/367 cluster is highly conserved among vertebrates and made up of five members, including miR-367, miR-302a, miR-302b, miR-302c and miR-302d. miR-302/367 cluster plays an important role in cell proliferation, differentiation and reprogramming, affecting the development of tumor, cardiovascular system, nervous system and immune system. In this review, we will summarize the role of miR-302/367 cluster in embryonic stem cells and induced pluripotent stem cells and try to point out its relationship with tumors, cardiovascular system, nervous system and immune system.

HOXA-AS2 promotes type I endometrial carcinoma via miRNA-302c-3p-mediated regulation of ZFX

Background

HOXA cluster antisense RNA2 (HOXA-AS2), a long-chain non-coding RNA, plays an important role in the behavior of various malignant tumors. The roles of HOXA-AS2 in endometrial cancer remain unclear.

Methods

We test expression levels of HOXA-AS2, miRNA-302c-3p, the transcription factor zinc finger X-chromosomal protein (ZFX), and the chitinase-like protein YKL-40 in endometrial carcinoma by qRT-PCR and western blotting. Luciferase reporter and qRT-PCR assays were conducted to identify potential binding sites of HOXA-AS2 to miRNA-302c-3p. Cell cycle, migration and invasion ability of endometrial cancer cells were investigated using flow-cytometric analysis, CCK-8 and transwell assays, respectively.

Results

HOXA-AS2 levels were significantly increased in endometrial cancer specimens compared to normal endometrial specimens. Upregulated HOXA-AS2 promoted invasion and proliferation of type I endometrial cancer cells. HOXA-AS2 silenced miRNA-302c-3p by binding to it. MiRNA-302c-3p negatively regulates ZFX and YKL-40. Thus HOXA-AS2 promotes the development of type I endometrial cancer via miRNA-302c-3p-mediated regulation of ZFX.

Conclusions

These findings suggest that HOXA-AS2 can act as a new therapeutic target for type I endometrial cancer.

Regulatory mechanism of tumor suppressor gene miR-302b in malignant tumors

MicroRNAs are a class of endogenous non-coding RNA molecules that regulate the translation of proteins. They play important regulatory roles in the growth, development, and aging of organisms, as well as cell proliferation, differentiation, apoptosis, and even cancer. miR-302b can participate in the regulation of the expression of a variety of genes, and functions as a tumor suppressor gene in the occurrence, development, invasion, and metastasis of malignant tumors. This article discusses the expression of miR-302b in malignant tumors and its biological functions and molecular mechanism.

Upregulated cyclins may be novel genes for triple-negative breast cancer based on bioinformatic analysis

BACKGROUND

Triple-negative breast cancer (TNBC) is one of the leading causes of death among females around the world. However, the molecular mechanism of the disease among TNBC patients remains to be further studied.

METHODS

In our study, four microarray data and two high throughput sequencing data were acquired from the GEO database, and the differentially expressed genes (DEGs) between TNBC and normal tissues had been analyzed. Analysis of functional enrichment and pathway enrichment of DEGs was conducted by the Funrich software, and protein-protein interaction (PPI) network gained from the STRING, and hub genes were confirmed by the Cytoscape. Kaplan-Meier plotter (KM plotter) online dataset had been used to analyze DEGs of overall survival (OS), and progression-free survival (PFS).

RESULTS

In total, 1638 DEGs were gained in our study covering 984 upregulated and 654 downregulated genes. Moreover, a PPI network was constructed, and cyclin-dependent kinase 1 (CDK1), cyclin B1 (CCNB1), and cyclin A2 (CCNA2) were found as top genes with higher node degrees. CDK1, CCNA2, and CCNB1were obviously enriched in the cell cycle. The top upregulated genes including CDK1, CCNB1, CCNA2, and PLK1 were overexpressed in TNBC, and correlated with worse OS in breast cancer. High expression of CCNB1 was correlated with worse PFS in TNBC (HR = 1.42, 95% CI: 1.04-1.94, P = 0.028). Besides, there was a correlation between CCNB1 and CDK1 in TNBC, as well as between CCNA2 and CDK1 (r = 0.804, P < 0.001; r = 0.577, P < 0.001, respectively).

CONCLUSION

Our results suggest that cyclin CDK1, CCNB1, and CCNA2 are overexpressed in TNBC and they could act as novel biomarkers for the diagnosis and treatment of TNBC.

miR-16 enhances miR-302/367-induced reprogramming and tumor suppression in breast cancer cells

Overexpression of either miR-302 or miR-302/367 cluster induces reprogramming of cancer cells and exerts tumor-suppressive effects by induction of mesenchymal-to-epithelial transition, apoptosis and a less proliferative capacity. Several reports have described miR-16 as a tumor suppressor microRNA (miRNA). Here, we studied the impact of exogenous induction of miR-16 in MDA-MB-231 and SK-BR-3 breast cancer cells following overexpression of miR-302/367 cluster and investigated whether transfection of these cells by a mature miR-16 mimic could affect the reprogramming state of the cells and their tumorigenicity. miR-16 enhanced the expression levels of OCT4A, SOX2, and NANOG, generally known as transcription or pluripotency factors, and suppressed proliferation and invasiveness of these cells. Meanwhile, inhibition of miR-16 counteracted both the reprogramming effect and the antitumor function of miR-302/367 in the breast cancer cells. Current results indicate that miR-16 can work as an adjuvant to improve both cancer cell reprogramming and tumor-suppressive function of miR-302/367 cluster in MDA-MB-231 and SK-BR-3 cells, while its inhibition counteracts all of these effects. Combined application of miRNAs that share some common targets in cancer cell signaling pathways may provide new approaches for repression of multiple hallmarks of cancer.

CircRhoC promotes tumorigenicity and progression in ovarian cancer by functioning as a miR-302e sponge to positively regulate VEGFA

Ovarian cancer is a leading cause of deaths due to gynaecological malignancy. While endogenous non‐coding circular RNAs (circRNAs) in cancer have attracted attention, their roles in ovarian cancer are not known. We used qRT‐PCR to quantify expression of circRhoC in ovarian cancer tissues and normal tissues. The effects of overexpressing or destruction of circRhoC on the phenotype of ovarian cancer cells were assessed both in vitro and in vivo. Dual‐luciferase reporter assay assesses the microRNA sponge function of circRhoC. Western blotting was used to confirm the effects of circRhoC and microRNA on target gene expression. Our results showed that circRhoC was significantly up‐regulated in ovarian cancer tissues compared to normal ovarian tissues. Overexpression of circRhoC in CAOV3 ovarian cancer cell increased cell viability, migration and invasion ability; destroying circRhoC in A2780 had the opposite effects and inhibited ovarian tumour cell A2780 dissemination in the peritoneum in vivo. We confirmed circRhoC functions as a sponge for miR‐302e to positively regulate VEGFA; FISH experiments showed that circRhoC could co‐focal with miR‐302e; besides, overexpression of miR‐302e reversed the ability of circRhoC to positively regulate VEGFA, and what's more, RIP assay showed that circRhoC could directly bind with VEGFA; besides, VEGFA expression level in ovarian cancer tissues was positively associated with circRhoC expression. In conclusion, the oncogenic effect of RhoC in ovarian cancer is at least in part due to circRhoC, which functions not only as a miR‐302e sponge to positively regulate VEGFA protein expression, but may also directly bind and modulate VEGFA expression.

Targeted Cancer Cell Killing by Highly Selective miRNA-Triggered Activation of a Prokaryotic Toxin-Antitoxin System

Although not evolved to function in eukaryotes, prokaryotic toxin Kid induces apoptosis in human cells, and this is avoided by coexpression of its neutralizing antitoxin, Kis. Inspired by the way Kid becomes active in bacterial cells we had previously engineered a synthetic toxin-antitoxin system bearing a Kis protein variant that is selectively degraded in cells expressing viral oncoprotein E6, thus achieving highly selective killing of cancer cells transformed by human papillomavirus. Here we aimed to broaden the type of oncogenic insults, and therefore of cancer cells, that can be targeted using this approach. We show that appropriate linkage of the kis gene to a single, fully complementary, target site for an oncogenic human microRNA enables the construction of a synthetic toxin-antitoxin pair that selectively kills cancer cells overexpressing that particular microRNA. Importantly, the resulting system spares nontargeted cells from collateral damage, even when they overexpress highly homologous, though nontargeted, microRNAs.

Repression of TGF-β Signaling in Breast Cancer Cells by miR-302/367 Cluster

Objective

Epigenetic alterations of the malignantly transformed cells have increasingly been regarded as an important event in the carcinogenic development. Induction of some miRNAs such as miR-302/367 cluster has been shown to induce reprogramming of breast cancer cells and exert a tumor suppressive role by induction of mesenchymal to epithelial transition, apoptosis and a lower proliferation rate. Here, we aimed to investigate the impact of miR-302/367 overexpression on transforming growth factor-beta (TGF-β) signaling and how this may contribute to tumor suppressive effects of miR-302/367 cluster.

Materials and Methods

In this experimental study, MDA-MB-231 and SK-BR-3 breast cancer cells were cultured and transfected with miR-302/367 expressing lentivector. The impact of miR-302/367 overexpression on several mediators of TGF-β signaling and cell cycle was assessed by quantitative real-time polymerase chain reaction (qPCR) and flow cytometry.

Results

Ectopic expression of miR-302/367 cluster downregulated expression of some downstream elements of TGF-β pathway in MDA-MB-231 and SK-BR-3 breast cancer cell lines. Overexpression of miR-302/367 cluster inhibited proliferation of the breast cancer cells by suppressing the S-phase of cell cycle which was in accordance with inhibition of TGF-β pathway.

Conclusion

TGF-β signaling is one of the key pathways in tumor progression and a general suppression of TGF-β mediators by the pleiotropically acting miR-302/367 cluster may be one of the important reasons for its anti-tumor effects in breast cancer cells.

MicroRNA-551b-3p inhibits tumour growth of human cholangiocarcinoma by targeting Cyclin D1

MicroRNAs (miRNAs) are powerful regulators in the tumorigenesis of cholangiocarcinoma (CCA). Previous studies report that miR‐551b‐3p acts as an oncogenic factor in ovarian cancer, but plays a tumour suppressive role in gastric cancer. However, the expression pattern and potential function of miR‐551b‐3p were still unclear in CCA. Therefore, this study aimed to explore the expression of miR‐551b‐3p and its role as well as molecular mechanism in CCA. Analysis of TCGA dataset suggested that miR‐551b‐3p was under‐expressed in CCA tissues compared to normal bile duct tissues. Furthermore, our data confirmed the decreased levels of miR‐551b‐3p in CCA samples and cell lines. Interestingly, TCGA data suggested that low miR‐551b‐3p level indicated reduced overall survival of CCA patients. Gain‐ and loss‐of‐function experiments found that miR‐551b‐3p inhibited the proliferation, G1‐S phase transition and induced apoptosis of CCA cells. In vivo experiments revealed that ectopic expression of miR‐551b‐3p inhibited tumour growth of CCA in mice. Further investigation demonstrated that miR‐551b‐3p directly bond to the 3′‐UTR of Cyclin D1 (CCND1) mRNA and negatively regulated the abundance of CCND1 in CCA cells. An inverse correlation between miR‐551b‐3p expression and the level of CCND1 mRNA was detected in CCA tissues from TCGA dataset. Notably, CCND1 knockdown showed similar effects to miR‐551b‐3p overexpression in HuCCT‐1 cells. CCND1 restoration rescued miR‐551b‐3p‐induced inhibition of proliferation, G1 phase arrest and apoptosis in HuCCT‐1 cells. In summary, miR‐551b‐3p inhibits the expression of CCND1 to suppress CCA cell proliferation and induce apoptosis, which may provide a theoretical basis for improving CCA treatment.

Human Umbilical Cord Mesenchymal Stem Cell-Derived Extracellular Vesicles Inhibit Endometrial Cancer Cell Proliferation and Migration through Delivery of Exogenous miR-302a

MicroRNAs (miRNAs) are potential therapeutic targets in endometrial cancer, but the difficulties associated with their delivery to tumor target cells have hampered their applications. Human umbilical cord mesenchymal stem cells (hUCMSCs) have a well-recognized tumor-homing ability, emphasizing the capacity of tumor-targeted delivery of extracellular vesicles. hUCMSCs release extracellular vesicles rich in miRNAs, which play a vital role in intercellular communication. The purpose of this study was to verify a potential tumor suppressor microRNA, miR-302a, and engineered hUCMSC extracellular vesicles enriched with miR-302a for therapy of endometrial cancer. Here, we observed that miR-302a was significantly downregulated in endometrial cancer tissues when compared with adjacent tissues. Overexpression of miR-302a in endometrial cancer cells robustly suppressed cell proliferation and migration. Meanwhile, the proliferation and migration were significantly inhibited in endometrial cancer cells when cultured with miR-302a-loaded extracellular vesicles derived from hUCMSCs. Importantly, our data showed that engineered extracellular vesicles rich in miR-302 significantly inhibited the expression of cyclin D1 and suppressed AKT signaling pathway in endometrial cancer cells. These results suggested that exogenous miR-302a delivered by hUCMSC-derived extracellular vesicles has exciting potential as an effective anticancer therapy.

Non-coding RNAs in endometriosis: a narrative review

BACKGROUND

Endometriosis is a benign gynaecological disorder, which affects 10% of reproductive-aged women and is characterized by endometrial cells from the lining of the uterus being found outside the uterine cavity. However, the pathophysiological mechanisms causing the development of this heterogeneous disease remain enigmatic, and a lack of effective biomarkers necessitates surgical intervention for diagnosis. There is international recognition that accurate non-invasive diagnostic tests and more effective therapies are urgently needed. Non-coding RNA (ncRNA) molecules, which are important regulators of cellular function, have been implicated in many chronic conditions. In endometriosis, transcriptome profiling of tissue samples and functional in vivo and in vitro studies demonstrate that ncRNAs are key contributors to the disease process.

OBJECTIVE AND RATIONALE

In this review, we outline the biogenesis of various ncRNAs relevant to endometriosis and then summarize the evidence indicating their roles in regulatory pathways that govern disease establishment and progression.

SEARCH METHODS

Articles from 2000 to 2016 were selected for relevance, validity and quality, from results obtained in PubMed, MEDLINE and Google Scholar using the following search terms: ncRNA and reproduction; ncRNA and endometriosis; miRNA and endometriosis; lncRNA and endometriosis; siRNA and endometriosis; endometriosis; endometrial; cervical; ovary; uterus; reproductive tract. All articles were independently screened for eligibility by the authors.

OUTCOMES

This review integrates extensive information from all relevant published studies focusing on microRNAs, long ncRNAs and short inhibitory RNAs in endometriosis. We outline the biological function and synthesis of microRNAs, long ncRNAs and short inhibitory RNAs and provide detailed findings from human research as well as functional studies carried out both in vitro and in vivo, including animal models. Although variability in findings between individual studies exists, collectively, the extant literature justifies the conclusion that dysregulated ncRNAs are a significant element of the endometriosis condition.

WIDER IMPLICATIONS

There is a compelling case that microRNAs, long non-coding RNAs and short inhibitory RNAs have the potential to influence endometriosis development and persistence through modulating inflammation, proliferation, angiogenesis and tissue remodelling. Rapid advances in ncRNA biomarker discovery and therapeutics relevant to endometriosis are emerging. Unravelling the significance of ncRNAs in endometriosis will pave the way for new diagnostic tests and identify new therapeutic targets and treatment approaches that have the potential to improve clinical options for women with this disabling condition.

The microRNA and the perspectives of miR-302

MiRNAs are naturally occurring, small, non-coding RNA molecules that post-transcriptionally regulate the expression of a large number of genes involved in various biological processes, either through mRNA degradation or through translation inhibition. MiRNAs play important roles in many aspects of physiology and pathology throughout the body, particularly in cancer, which have made miRNAs attractive tools and targets for translational research. The types of non-coding RNAs, biogenesis of miRNAs, circulating miRNAs, and direct delivery of miRNA were briefly reviewed. As a case of point, the role and perspective of miR-302, a family of ES-specific miRNA, on cancer, iPSCs, heart disease were presented.

microRNA-769 is downregulated in colorectal cancer and inhibits cancer progression by directly targeting cyclin-dependent kinase 1

BACKGROUND

In recent years, microRNAs (miRNAs) have been reported to be aberrantly expressed in colorectal cancer (CRC). The deregulation of miRNAs is implicated in the formation and progression of CRC, and participates in the regulation of a wide range of biological behaviors. Considering the crucial role of miRNAs in CRC, miRNAs are thought to have significant promise in the diagnosis and therapy of patients with this malignancy.

MATERIAL AND METHODS

Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was performed to detect miR-769 expression in CRC tissues and cell lines. MTT assay and flow cytometry analysis were used to determine the effects of miR-769 upregulation in CRC cell proliferation and apoptosis, respectively. The influence of miR-769 overexpression in CRC cell migration and invasion was evaluated through migration and invasion assays. Notably, the possible mechanisms underlying the action of miR-769 in CRC cells were explored.

RESULTS

In the present study, miR-769 was frequently found to be poorly expressed in CRC tissues and cell lines. Functional assays showed that recovery of miR-769 expression suppressed CRC cell proliferation, migration, and invasion, increased cell apoptosis in vitro, and inhibited tumor growth in vivo. Cyclin-dependent kinase 1 (CDK1) was the direct target of miR-769 in CRC cells. CDK1 was overexpressed in CRC tissue samples and negatively correlated with miR-769 expression. In addition, CDK1 inhibition imitated the tumor suppressor activity of miR-769 in CRC cells, and restoration of CDK1 expression partially abolished the tumor-suppressing roles of miR-769 in malignant CRC cells.

CONCLUSION

The results of this study demonstrated that miR-769 was downregulated in CRC and directly targeted CDK1 to be implicated in the regulation of CRC cell proliferation, apoptosis, migration and invasion. Thus, the miR-769/CDK1 axis might be an effective therapeutic target for treating patients with CRC.

MicroRNA-302a/d inhibits the self-renewal capability and cell cycle entry of liver cancer stem cells by targeting the E2F7/AKT axis

BACKGROUND

There is increasing evidence that liver cancer stem cells (LCSCs) contribute to hepatocellular carcinoma (HCC) initiation and progression. MicroRNA (miRNA) plays a significant functional role by directly regulating respective targets in LCSCs-triggered HCC, however, little is known about the function of the miRNA-302 family in LCSCs.

METHODS

MiRNAs microarray was used to detect the miRNAs involved in LCSCs maintenance and differentiation. Biological roles and the molecular mechanism of miRNA-302a/d and its target gene E2F7 were detected in HCC in vitro. The expression and correlation of miRNA-302a/d and E2F7 in HCC patients was evaluated by quantitative PCR and Kaplan-Meier survival analysis.

RESULTS

We found that the miRNA-302 family was downregulated during the spheroid formation of HCC cells and patients with lower miRNA-302a/d expression had shorter overall survival (OS) and progression-free survival (PFS). Moreover, E2F7 was confirmed to be directly targeted and inhibited by miRNA-302a/d. Furthermore, concomitant low expression of miRNA-302a/d and high expression of E2F7 correlated with a shorter median OS and PFS in HCC patients. Cellular functional analysis demonstrated that miRNA-302a/d negatively regulates self-renewal capability and cell cycle entry of liver cancer stem cells via suppression of its target gene E2F7 and its downstream AKT/β-catenin/CCND1 signaling pathway.

CONCLUSIONS

Our data provide the first evidence that E2F7 is a direct target of miRNA-302a/d and miRNA-302a/d inhibits the stemness of LCSCs and proliferation of HCC cells by targeting the E2F7/AKT/β-catenin/CCND1 signaling pathway.

Vitamin C counteracts miR-302/367-induced reprogramming of human breast cancer cells and restores their invasive and proliferative capacity

Epigenetic reprogramming by embryonic stem cell-specific miR-302/367 cluster has shown some tumor suppressive effects in cancer cells of different tissues such as skin, colon, and cervix. Vitamin C has been known as a reprogramming enhancer of human and mouse somatic cells. In this study, first we aimed to investigate whether exogenous induction of miR-302/367 in breast cancer cells shows the same tumor suppressive effects previously observed in other cancer cells lines, and whether vitamin C can enhance reprogramming of breast cancer cells and also improve the tumor suppressive function of miR-302/367 cluster. Overexpression of miR-302/367 cluster in MDA-MB-231 and SK-BR-3 breast cancer cells upregulated expression of miR-302/367 members and also some core pluripotency factors including OCT4A, SOX2 and NANOG, induced mesenchymal to epithelial transition, suppressed invasion, proliferation, and induced apoptosis in the both cell lines. However, treatment of the miR-302/367 transfected cells with vitamin C suppressed the expression of pluripotency factors and augmented the tumorigenicity of the breast cancer cells by restoring their proliferative and invasive capacity and compromising the apoptotic effect of miR-302/367. Supplementing the culture medium with vitamin C downregulated expression of TET1 gene which seems to be the reason behind the negative impact of vitamin C on the reprogramming efficiency of miR-302/367 cluster and its anti-tumor effects. Therefore application of vitamin C may not always serve as a reprogramming enhancer depending on its switching function on TET1. This phenomenon should be carefully considered when considering a reprogramming strategy for tumor suppression.

Shikonin enhances sensitization of gefitinib against wild-type EGFR non-small cell lung cancer via inhibition PKM2/stat3/cyclinD1 signal pathway

AIMS

Mutant EGFR Non-small cell lung cancer has benefit from gefitinib, but it has limited effect for wild-type EGFR tumors. Shikonin, a natural naphthoquinone isolated from a traditional Chinese medicine, the plant Lithospermum erythrorhizon (zicao), not only can inhibit the tumor growth, but also overcome cancer drug resistance. Our aim is to investigate whether shikonin can enhance antitumor effect of gefitinib in EGFR wild-type lung cancer cells in vitro and in vivo.

MATERIALS AND METHODS

CCK-8 was used to determine the proliferation of EGFR wild-type non-small cell lung cancer. Apoptosis and cell cycle were detected by flow cytometry. PKM2, STAT3, p-STAT3 and cyclinD1 were detected by Western blot. A549 tumor model was established to observe the antitumor effect of shikonin combination with gefitinib in vivo.

KEY FINDINGS

The results showed that combination of shikonin with gefitinib exhibited synergistic antitumor effect in vitro and in vivo. Its potential molecular mechanisms may be associated with inhibition of PKM2/STAT3/cyclinD1.

SIGNIFICANCE

These results provide a promising therapeutic approach for the treatment of wild-type EGFR non-small cell lung cancer.

MicroRNA-302 inhibits cell migration and invasion in cervical cancer by targeting DCUN1D1

MicroRNA serve crucial roles in a variety of human cancer types. The miR-302-367 cluster has been reported to suppress the proliferation of cervical carcinoma cells through the novel target AKT1; however, the molecular mechanism of miR-302 in cervical cancer metastasis remains unclear. The present study aimed to investigate the clinical significance of miR-302-3p expression in cervical cancer, and to examine the regulatory mechanism of miR-302-3p in the malignant phenotypes of cervical cancer cells. The present data indicated that miR-302-3p was significantly downregulated in cervical cancer tissues compared with the level in adjacent non-tumor tissues, and low expression of miR-302-3p was significantly associated with node metastasis, advanced clinical stage, and poor prognosis in patients with cervical cancer. Restoration of miR-302-3p expression caused a significant reduction in cervical cancer cell migration and invasion. Defective in cullin neddylation 1 domain containing 1 (DCUN1D1) was identified as a novel target gene of miR-302-3p, and miR-302-3p negatively regulated the mRNA and protein expression of DCUN1D1 in cervical cancer HeLa cells. Additionally, overexpression of DCUN1D1 rescued the effects of miR-302-3p on the migration and invasion of cervical cancer cells. Furthermore, DCUN1D1 was upregulated in cervical cancer tissues compared with the levels in adjacent tissues, and its high expression was associated with node metastasis, advanced clinical stage, and shorter survival time in patients with cervical cancer. Notably, a negative correlation between miR-302-3p and DCUN1D1 expression in cervical cancer tissues was observed. Taken together, the present study suggests that miR-302-3p serves a suppressive role in cervical cancer metastasis, partly at least, via directly targeting DCUN1D1. Therefore, miR-302-3p/DCUN1D1 may be a potential therapeutic target for cervical cancer treatment.

MicroRNA 302b-3p/302c-3p/302d-3p inhibits epithelial-mesenchymal transition and promotes apoptosis in human endometrial carcinoma cells

Background

Studies have shown that the microRNA miR-302 can affect the proliferation, migration and cell cycle progression of endometrial carcinoma (EC). miR-302 clusters have been shown to play an important role in the proliferation and differentiation of cancer cells and in their tumorigenicity.

Subjects and methods

In this study, we detected the expression of genes through quantitative reverse transcription polymerase chain reaction (qRT-PCR). We detected the expression of proteins through Western blot. The Annexin V-fluorescein isothiocyanate (FITC)/propidium iodide (PI) double-staining assay were used to detect the ability of miR-302b-3p/302c-3p/302d-3p to affect the cell apoptosis. The CCK-8 were used to detect the ability of miR-302b-3p/302c-3p/302d-3p to affect the cell proliferation. The Cell cycle analysis were used to detect the ability of miR-302b-3p/302c-3p/302d-3p to affect the cell cycle. Finally, the wound healing assay was used to detect the ability of miR-302b-3p/302c-3p/302d-3p to impact cell migration.

Results

We found that miR-302b-3p/302c-3p/302d-3p of the miR-302 cluster was downregulated in EC, and it altered the epithelial-mesenchymal transition (EMT) process in the EC cell lines Ishikawa and HEC-1A. Western blot and the Annexin V- FITC/PI double-staining assay were used to detect the ability of miR-302b-3p/302c-3p/302d-3p to promote the apoptosis of Ishikawa and HEC-1A cells. In addition, qRT-PCR results showed that overexpression of miR-302b-3p/302c-3p/302d-3p significantly inhibited the expression of ZEB1, suppressed the expression of Bcl-2 and promoted the expression of BAX. The overexpression of miR-302b-3p/302c-3p/302d-3p inhibited the proliferation and migration of Ishikawa and HEC-1A cells. Cell cycle analysis showed that miR-302b-3p/302c-3p/302d-3p arrested cell cycle progression in the G0/G1 phase.

Conclusion

All results showed that miR-302b-3p/302c-3p/302d-3p can be used as a tumor suppressor in EC and is expected to be a new target for the treatment of EC.

Inhibition of PHLPP2/cyclin D1 protein translation contributes to the tumor suppressive effect of NFκB2 (p100)

Although the precursor protein of NFκB2 (p100) is thought to act as a tumor suppressor in mammalian cells, the molecular mechanism of its anti-tumor activity is far from clear. Here, we are, for the first time, to report that p100 protein expression was dramatically decreased in bladder cancers of N-butyl-N-(4-hydroxybutyl)-nitrosamine (BBN)-treated mice and human patients. Knockdown of p100 in cultured human bladder cancer cells promoted anchorage-independent growth accompanied with elevating abundance of cell-cycle-related proteins and accelerated cell-cycle progression. Above effects could be completely reversed by ectopically expression of p100, but not p52. Mechanistically, p100 inhibited Cyclin D1 protein translation by activating the transcription of LARP7 and its hosted miR-302d, which could directly bind to 3'-UTR of cyclin d1 mRNA and inhibited its protein translation. Furthermore, p100 suppressed the expression of PHLPP2 (PH domain and leucine-rich repeat protein phosphatases 2), thus promoting CREB phosphorylation at Ser133 and subsequently leading to miR-302d transcription. Taken together, our studies not only for the first time establish p100 as a key tumor suppressor of bladder cancer growth, but also identify a novel molecular cascade of PHLPP2/CREB/miR-302d that mediates the tumor suppressive function of p100.

The miR-302-Mediated Induction of Pluripotent Stem Cells (iPSC): Multiple Synergistic Reprogramming Mechanisms

Pluripotency represents a unique feature of embryonic stem cells (ESCs). To generate ESC-like-induced pluripotent stem cells (iPSCs) derived from somatic cells, the cell genome needs to be reset and reprogrammed to express the ESC-specific transcriptome. Numerous studies have shown that genomic DNA demethylation is required for epigenetic reprogramming of somatic cell nuclei to form iPSCs; yet, the mechanism remains largely unclear. In ESCs, the reprogramming process goes through two critical stages: germline and zygotic demethylation, both of which erase genomic DNA methylation sites and hence allow for different gene expression patterns to be reset into a pluripotent state. Recently, miR-302, an ESC-specific microRNA (miRNA), was found to play an essential role in four aspects of this reprogramming mechanism-(1) initiating global genomic DNA demethylation, (2) activating ESC-specific gene expression, (3) inhibiting developmental signaling, and (4) preventing stem cell tumorigenicity. In this review, we will summarize miR-302 functions in all four reprogramming aspects and further discuss how these findings may improve the efficiency and safety of the current iPSC technology.

The MicroRNA

MicroRNAs (miRNAs), widely distributed, small regulatory RNA genes, target both messenger RNA (mRNA) degradation and suppression of protein translation based on sequence complementarity between the miRNA and its targeted mRNA. Different names have been used to describe various types of miRNA. During evolution, RNA retroviruses or transgenes invaded the eukaryotic genome and were inserted itself in the noncoding regions of DNA, conceivably acting as transposon-like jumping genes, providing defense from viral invasion and fine-tuning of gene expression as a secondary level of gene modulation in eukaryotes. When a transposon is inserted in the intron, it becomes an intronic miRNA, taking advantage of the protein synthesis machinery, i.e., mRNA transcription and splicing, as a means for processing and maturation. MiRNAs have been found to play an important, but not life-threatening, role in embryonic development. They might play a pivotal role in diverse biological systems in various organisms, facilitating a quick response and accurate plotting of body physiology and structures. Based on these unique properties, manufactured intronic miRNAs have been developed for in vitro evaluation of gene function, in vivo gene therapy, and generation of transgenic animal models. The biogenesis of miRNAs, circulating miRNAs, miRNAs and cancer, iPSCs, and heart disease are presented in this chapter, highlighting some recent studies on these topics.

Efficacy of Shikonin against Esophageal Cancer Cells and its possible mechanisms in vitro and in vivo

Increasing evidences indicate that shikonin can suppress the tumor growth. However, the mechanisms remain elusive. In the present study, we investigated the effects and mechanisms of shikonin against esophageal cancer. The expression of hypoxia inducible factor 1α (HIF1α) and pyruvate kinase M2 (PKM2) in esophageal cancer tissues and cells was detected by immunohistochemistry and Western blot. CCK-8 was used to examine the esophageal cancer cell viability. Apoptosis and cell cycle were analyzed by flow cytometry. The expression of EGFR, PI3K, Akt, p-AKT, mTOR, HIF1α and PKM2 was detected by Western blot. EC109/pkm2 was established by lentivirus transducer. Ec109 tumor model was founded to observe the antitumor effect of shikonin in vivo. We found that HIF1α and PKM2 protein expression levels were higher in esophageal cancer tissues and cells than normal esophageal tissues and cells. Shikonin reduced esophageal cancer cells viability and induced cell cycle arrest and apoptosis. Shikonin decreased EGFR, PI3K, p-AKT, HIF1α and PKM2 expression. Overexpression of PKM2 could enhance resistance of esophageal cancer cells to shikonin. In vivo we found that shikonin reduced tumor burden, inducing cell arrest and apoptosis. Taken together, shikonin has a significant antitumor effect in the esophageal cancer by regulating HIF1α/PKM2 signal pathway.

SOX15 regulates proliferation and migration of endometrial cancer cells

The study aimed to investigate the effects of Sry-like high mobility group box 15 (SOX15) on proliferation and migration of endometrial cancer (EC) cells. Immunohistochemistry (IHC) was applied to determine the expression of SOX15 in EC tissues and adjacent tissues. We used cell transfection method to construct the HEC-1-A and Ishikawa cell lines with stable overexpression and low expression SOX15. Reverse-transcription quantitative real-time PCR (RT-qPCR) and Western blot were performed to examine expression of SOX15 mRNA and SOX15 protein, respectively. By conducting a series of cell proliferation assay and migration assay, we analyzed the influence of SOX15 overexpression or low expression on EC cell proliferation and migration. The expression of SOX15 mRNA and protein in EC tissues was significantly lower than that in adjacent tissues. After lentivirus-transfecting SOX15, the expression level of SOX15 mRNA and protein was significantly increased in cells of SOX15 group, and decreased in sh-SOX15 group. Overexpression of SOX15 could suppress cell proliferation, while down-regulation of SOX15 increased cell proliferation. Flow cytometry results indicated that overexpression of SOX15 induced the ratio of cell-cycle arrest in G₁ stage. In addition, Transwell migration assay results showed that SOX15 overexpression significantly inhibited cell migration, and also down-regulation of SOX15 promoted the migration. As a whole, SOX15 could regulate the proliferation and migration of EC cells and up- regulation of SOX15 could be valuable for EC treatment.

A guide for endometrial cancer cell lines functional assays using the measurements of electronic impedance

Endometrial cancer cell lines are critical tools to investigate the molecular mechanism of tumorigenesis using the end point cell-based assay such as proliferation, cytotoxicity, apoptosis, anoikis or migration and invasion. The proper assay optimization and performance is essential for physiologically relevant results interpretation. In this study we use label-free real-time cell analysis platform (xCELLigence) to optimize growing conditions for proliferation and migration experiments of two types of endometrial cancer cell lines HEC-1-B, HEC-1-A, KLE, and Ishikawa. Profiling of cell lines by cell index measurement in proliferation and migration experiments was performed. Our experimental approach allowed us to monitor particular stage of the cell growth, to see the relation between seeding density and dynamic cell growth as well as to choose the optimal serum concentration as chemoattractant in migration experiment. The highest rate of proliferation was shown for Ishikawa cells. The rapid pace of cellular migration was observed in case of KLE and HEC-1-B cells as compared to weak migratory activity of Ishikawa cells. The cell index that reflects the cell status characterized real-time cytological profile of each analyzed cell line. These cell profiles were crucial for better planning the classical end-point assays used in further research.

MiR-520b as a novel molecular target for suppressing stemness phenotype of head-neck cancer by inhibiting CD44

Cancer stem cells preferentially acquire the specific characteristics of stress tolerance and high mobility, allowing them to progress to a therapy-refractive state. To identify a critical molecule to regulate cancer stemness is indispensable to erratically cure cancer. In this study, we identified miR-520b as a novel molecular target to suppress head-neck cancer (HNC) with stemness phenotype. MiR-520b inhibited cellular migration and invasion via the mechanism of epithelial-mesenchymal transition. It also sensitized cells to therapeutic drug and irradiation. Significantly, miR-520b suppressed spheroid cell formation, as well as reduced expressions of multiple stemness regulators (Nestin, Twist, Nanog, Oct4). The CD44 molecule was identified as a direct target of miR-520b, as shown by the reverse correlative expressions, the response to miR-520 modulation, the luciferase reporter assay, and the functional rescue analyses. These cellular results were confirmed by a tumor xenograft mice study. Administration of miR-520b dramatically restrained tumorigenesis and liver colonization. Conversely, miR-520b silencing led to an acceleration of tumor growth. Taken together, our study demonstrated that miR-520b inhibits the malignancy of HNC through regulation of cancer stemness conversion by targeting CD44. MiR-520b may serve as an emerging therapeutic target that may be further developed for the intervention of refractory HNC.

Cell-based therapy using miR-302-367 expressing cells represses glioblastoma growth

Glioblastomas are incurable primary brain tumors that affect patients of all ages. The aggressiveness of this cancer has been attributed in part to the persistence of treatment-resistant glioblastoma stem-like cells. We have previously discovered the tumor-suppressor properties of the microRNA cluster miR-302-367, representing a potential treatment for glioblastoma. Here, we attempted to develop a cell-based therapy by taking advantage of the capability of glioma cells to secrete exosomes that enclose small RNA molecules. We engineered primary glioma cells to stably express the miR-302-367. Remarkably, these cells altered, in a paracrine-dependent manner, the expression of stemness markers, the proliferation and the tumorigenicity of neighboring glioblastoma cells. Further characterization of the secretome derived from miR-302-367 expressing cells showed that a large amount of miR-302-367 was enclosed in exosomes, which were internalized by the neighboring glioblastoma cells. This miR-302-367 cell-to-cell transfer resulted in the inhibition of its targets such as CXCR4/SDF1, SHH, cyclin D, cyclin A and E2F1. Orthotopic xenograft of miR-302-367-expressing cells together with glioblastoma stem-like cells efficiently altered the tumor development in mice brain.

Selumetinib suppresses cell proliferation, migration and trigger apoptosis, G1 arrest in triple-negative breast cancer cells

BACKGROUND

Triple-negative breast cancer (TNBC) has aggressive progression with poor prognosis and ineffective treatments. Selumetinib is an allosteric, ATP-noncompetitive inhibitor of MEK1/2, which has benn known as effective antineoplastic drugs for several malignant tumors. We hypothesized that Selumetinib might be potential drug for TNBC and explore the mechanism.

METHODS

After treated with Selumetinib, the viability and mobility of HCC1937 and MDA-MB-231 were detected by MTT, tunnel, wound-healing assay, transwell assay and FCM methods. MiR array was used to analysis the change of miRs. We predicted and verified CUL1 is the target of miR-302a using Luciferase reporter assay. We also silenced the CUL1 by siRNA, to clarify whether CUL1 take part in the cell proliferation, migration and regulated its substrate TIMP1 and TRAF2. Moreover, after transfection, the antagomir of miR-302a and CUL1 over-expressed plasmid into HCC1937 and MDA-MB-231 cell accompanied with the Selumetinib treatment, we detected the proliferation and migration again.

RESULTS

Selumetinib reduce the proliferation, migration, triggered apoptosis and G1 arrest in TNBC cell lines. In this process, the miR-302a was up-regulated and inhibited the CUL1 expression. The later negatively regulated the TIMP1 and TRAF2. As soon as we knockdown miR-302a and over-expression CUL1 in TNBC cells, the cytotoxicity of Selumetinib was reversed.

CONCLUSIONS

MiR-302a targeted regulated the CUL1 expression and mediated the Selumetinib-induced cytotoxicity of triple-negative breast cancer.

A MicroRNA302-367-Erk1/2-Klf2-S1pr1 Pathway Prevents Tumor Growth via Restricting Angiogenesis and Improving Vascular Stability

RATIONALE

Angiogenic hypersprouting and leaky vessels are essential for tumor growth. MicroRNAs have unique therapeutic advantages by targeting multiple pathways of tumor-associated angiogenesis, but the function of individual miRNAs of miR302-367 cluster in angiogenesis and tumors has not yet been fully evaluated.

OBJECTIVE

To investigate the functions of miR302-367 in developmental angiogenesis and tumor angiogenesis and explore the molecular mechanisms of microRNA for the treatment of pathological neovascularization-related diseases.

METHODS AND RESULTS

Here, we show that miR302-367 elevation in endothelial cells reduces retinal sprouting angiogenesis and promotes vascular stability in vivo, ex vivo, and in vitro. Erk1/2 is identified as direct target of miR302-367, and downregulation of Erk1/2 on miR302-367 elevation in endothelial cells increases the expression of Klf2 and in turn S1pr1 and its downstream target VE-cadherin, suppressing angiogenesis and improving vascular stability. Conversely, both pharmacological blockade and genetic deletion of S1pr1 in endothelial cells reverse the antiangiogenic and vascular stabilizing effect of miR302-367 in mice. Tumor angiogenesis shares features of developmental angiogenesis, and endothelial specific elevation of miR302-367 reduces tumor growth by restricting sprout angiogenesis and decreasing vascular permeability via the same Erk1/2-Klf2-S1pr1 pathways.

CONCLUSIONS

MiR302-367 regulation of an Erk1/2-Klf2-S1pr1 pathway in the endothelium advances our understanding of angiogenesis, meanwhile also provides opportunities for therapeutic intervention of tumor growth.

The miR-302/367 cluster: a comprehensive update on its evolution and functions

microRNAs are a subclass of small non-coding RNAs that fine-tune the regulation of gene expression at the post-transcriptional level. The miR-302/367 cluster, generally consisting of five members, miR-367, miR-302d, miR-302a, miR-302c and miR-302b, is ubiquitously distributed in vertebrates and occupies an intragenic cluster located in the gene La-related protein 7 (LARP7). The cluster was demonstrated to play an important role in diverse biological processes, such as the pluripotency of human embryonic stem cells (hESCs), self-renewal and reprogramming. This paper provides an overview of the mir-302/367 cluster, discusses our current understanding of the cluster's evolutionary history and transcriptional regulation and reviews the literature surrounding the cluster's roles in cell cycle regulation, epigenetic regulation and different cellular signalling pathways.

The future therapy of endometrial cancer: microRNA's functionality, capability, and putative clinical application

PURPOSE

Endometrial cancer (EC) therapy is characterized by the heterogeneity of EC subtypes resulting in unclear clinical behavior as well as in unsatisfactory treatment options. The available biomarkers, such as cellular tumor antigen p53 (TP53), phosphatidylinositol 3,4,5-trisphosphate 3-phosphatase and dual-specificity protein phosphatase (PTEN), and phosphatidylinositol 4,5-bisphosphate 3-kinase catalytic subunit alpha (PIK3CA) genes alone might not be sufficient, and thus, new predictive and prognostic biomarkers are urgently required. The biomolecule class of microRNA represents a group of endogenously expressed regulatory factors primarily involved in control of pivotal cancer-related mechanisms including cell cycle, proliferation, apoptosis, and metastasis. Here, we review the current state of science regarding microRNA functionality in EC progression.

Downregulation of the Genes Involved in Reprogramming (SOX2, c-MYC, miR-302, miR-145, and P21) in Gastric Adenocarcinoma

PURPOSE

Many cell signaling pathways essential for normal stem cell development are involved in cancer initiation and progression. In the present study, motivated by a possible contribution of reprogramming process in induction of cancer, we compared the expression level of main genes involved in iPS generation, i.e., miR-302, miR-145, SOX2, c-MYC, and P21, in a series of tumor and non-tumor tissues of stomach.

METHODS

A total number of 34 tumors and their matched non-tumor (as control) gastric surgical specimens were obtained. The expression of the candidate genes was evaluated by using real-time PCR and immunohistochemistry (IHC) techniques.

RESULTS

Our data revealed a significant downregulation of miR-302b, P21, and miR-145 genes in intestinal and SOX2 gene in diffuse type of tumor samples. SOX2, but not the other genes, showed a significant downregulation in both proximal (cardia and fundus) and distal (body and antrum) sites of stomach. Based on receiver-operating characteristic (ROC) analyses, the highest total area under the curve (AUC) was found for SOX2 (AUC = 82 %, P < 0.001). Interestingly, all tumor samples revealed a negative signal for c-MYC expression, while non-tumor samples represented an intense cytoplasmic staining.

CONCLUSIONS

Despite the fact that some hESC-specific genes are upregulated in tumors, our data revealed a significant downregulation of all candidate genes, except for c-MYC, in tumor samples of stomach. Moreover, ROC data demonstrated that SOX2 gene expression index is a better potential biomarker of gastric cancer, compared to other tested genes. SOX2 expression has a good sensitivity and specificity to discriminate correctly between tumor/non-tumor and also high/low grades of tumor malignancy. It seems downregulation of miR-302b, miR-145, and P21 could contribute to gastric tumor initiation and progression.

In vitro antiproliferative activity of 2,3-dihydroxy-9,10-anthraquinone induced apoptosis against COLO320 cells through cytochrome c release caspase mediated pathway with PI3K/AKT and COX-2 inhibition

The present study investigated the anticancer activity of 2,3-dihydroxy-9,10-anthraquinone against different cancer cells such as MCF-7, COLO320, HepG-2, Skov-3, MOLM-14, NB-4, CEM, K562, Jurkat, HL-60, U937, IM-9 and Vero. 2,3-dihydroxy-9,10-anthraquinone showed good antiproliferative activity against COLO320 cells when compared to other tested cells. The cytotoxicity results showed 79.8% activity at the dose of 2.07 μM with IC50 value of 0.13 μM at 24 h in COLO320 cells. So we chose COLO320 cells for further anticancer studies. mRNA expression was confirmed by qPCR analysis using SYBR green method. Treatment with 2,3-dihydroxy-9,10-anthraquinone was found to trigger intrinsic apoptotic pathway as indicated by down regulation of Bcl-2, Bcl-xl; up regulation of Bim, Bax, Bad; release of cytochrome c and pro-caspases cleaving to caspases. Furthermore, 2,3-dihydroxy-9,10-anthraquinone stopped at G0/G1 phase with modulation in protein levels of cyclins. On the other hand PI3K/AKT signaling plays an important role in cell metabolism. We found that 2,3-dihydroxy-9,10-anthraquinone inhibits PI3K/AKT activity after treatment. Also, COX-2 enzyme plays a major role in colorectal cancer. Our results showed that the treatment significantly reduced COX-2 enzyme in COLO320 cells. These results indicated antiproliferative activity of 2,3-dihydroxy-9,10-anthraquinone involving apoptotic pathways, mitochondrial functions, cell cycle checkpoint and controlling the over expression genes during the colorectal cancer. Molecular docking studies showed that the compound bound stably to the active sites of Bcl-2, COX-2, PI3K and AKT. This is the first report of anticancer mechanism involving 2,3-dihydroxy-9,10-anthraquinone in COLO320 cells. The present results might provide helpful suggestions for the design of antitumor drugs toward colorectal cancer treatment.

Long noncoding RNAs as potential biomarkers in gastric cancer: Opportunities and challenges

Gastric cancer (GC) is a major threat to human health, and its prognosis is poor due to the lack of appropriate biomarkers. LncRNAs are a group of non-protein-coding RNAs that regulate gene expression at the transcriptional or posttranscriptional level. LncRNAs play essential roles in GC initiation and development in the same way as oncogenes or tumour suppressor genes. Recent investigations have revealed that lncRNAs are often aberrantly expressed in GC; are involved in cell proliferation, apoptosis, migration and invasion; and correlate with the malignant phenotype of GC. LncRNAs, especially the lncRNAs present in the blood and gastric juice, show potential value as biomarkers for the diagnosis of GC or for determining disease prognosis. However, there are still many challenges to be faced before lncRNAs can be used in clinical applications. In this review, we summarise lncRNAs as the potential biomarkers for GC and the current challenges associated with the clinical application.

MiR-302/367 regulate neural progenitor proliferation, differentiation timing, and survival in neurulation

How neural progenitor cell (NPC) behaviors are temporally controlled in early developing embryos remains undefined. The in vivo functions of microRNAs (miRNAs) in early mammalian development remain largely unknown. Mir-302/367 is a miRNA cluster that encodes miR-367 and four miR-302 members (miR302a-d). We show that miR-302b is highly expressed in early neuroepithelium and its expression decline as development progresses. We generated a mir-302/367 knockout mouse model and found that deletion of mir-302/367 results in an early embryonic lethality and open neural tube defect (NTD). NPCs exhibit enhanced proliferation, precocious differentiation, and decreased cell survival in mutant embryos. Furthermore, we identified Fgf15, Cyclin D1, and D2 as direct targets of miR-302 in NPCs in vivo, and their expression is enhanced in mutant NPCs. Ectopic expression of Cyclin D1 and D2 increases NPC proliferation, while FGF19 (human ortholog of Fgf15) overexpression leads to an increase of NPC differentiation. Thus, these findings reveal essential roles of miR-302/367 in orchestrating gene expression and NPC behaviors in neurulation; they also point to miRNAs as critical genetic components associated with neural tube formation.

Antitumor effect of metformin on cholangiocarcinoma: In vitro and in vivo studies

Cholangiocarcinoma (CCA) is the most common biliary malignancy and the second most common hepatic malignancy after hepatocellular carcinoma (HCC). Treatment with the anti-diabetic drug metformin has been associated with reduced cancer incidence in patients with type 2 diabetes. Thus, the present study evaluated the effects of metformin on human CCA cell proliferation in vitro and in vivo and identified the microRNAs associated with its antitumor effects. Metformin inhibited the proliferation of the CCA cell lines HuCCT-1 and TFK-1 and blocked the G0 to G1 cell cycle transition, accompanied by AMP kinase pathway activation. Metformin treatment also led to marked decreases in cyclin D1 and cyclin-dependent kinase (Cdk) 4 protein levels and retinoblastoma protein phosphorylation. However, this drug did not affect p27kip protein expression. In addition, it reduced the phosphorylation of Axl, EphA10, ALK and PYK, as well as tumor proliferation in athymic nude mice with xenograft tumors. Furthermore, it markedly altered microRNA expression. These findings suggest that metformin may have clinical use in the treatment of CCA.

miR-582-5p inhibits proliferation of hepatocellular carcinoma by targeting CDK1 and AKT3

microRNAs play an important role in the progression of hepatocellular carcinoma (HCC). In this study, we found that miR-582-5p expression was downregulated in hepatoma tissues and HCC cell lines. Upregulation of miR-582-5p reduced colony number, inhibited cellular proliferation, and arrested cell cycle in G0/G1 phase. When miR-582-5p was inhibited, the colony number was increased and cellular proliferation and cell cycle were promoted. Further studies showed that miR-582-5p regulated the progression of HCC through directly inhibiting the expression of CDK1 and AKT3, and indirectly inhibiting the expression of cyclinD1.

The role of microRNAs in the pathogenesis of endometrial cancer: a systematic review

INTRODUCTION

Epigenetics seem to play a primary role in the current research on the pathogenesis of different types of endometrial cancer. Data so far indicate that microRNAs regulate different pathways that could lead to carcinogenesis when not functioning properly. The aim of this review is to summarize current knowledge on microRNAs that have been associated with endometrial cancer development.

MATERIAL AND METHODS

From July 2014 to August 2014, we conducted a comprehensive research utilizing major online search engines (Pubmed, Crossref, Google Scholar). The main keywords used in our search were endometrial cancer/carcinoma; microRNA; epigenetics; novel biomarkers; pathogenesis.

RESULTS

Overall, we identified 155 studies, although only 77 were eligible for this review. Different miRNAs were identified to contribute either promoting the carcinogenesis in the endometrium or inhibiting different steps of endometrial cancer development. Tumour growth, cell proliferation, apoptosis and invasion metastasis have been identified as the main processes where miRNAs seem to be implicated.

CONCLUSIONS

microRNAs are effective regulators of gene expression that has a significant role in the pathogenesis of endometrial cancer. Research concerning possible therapeutic implications has been promising, although there is still a significant distance to be covered between research observations and clinical results. Extensive preclinical and translational research is still required to improve the efficacy and minimize unwanted effects of miRNAs-based therapy.

MicroRNAS in endometrial cancer: recent advances and potential clinical applications

Endometrial cancer is a common malignant gynecological tumor, but there are few biomarkers that are useful for early and accurate diagnosis and few treatments other than surgery. However, use of microRNAs (miRNAs) that induces gene downregulation in cells may permit effective and minimally invasive diagnosis and treatment. In endometrial cancer cells, expression levels of miRNAs including miR-185, miR-210 and miR-423 are upregulated and those of miR-let7e, miR-30c and miR-221 are downregulated compared to normal tissues, and these miRNAs are involved in carcinogenesis, invasion and metastasis. miRNAs with expression changes such as miR-181b, miR-324-3p and miR-518b may be used as prognostic biomarkers and transfection of miR-152 may inhibit cancer growth. However, most current studies of miRNAs are at a basic level and further work is needed to establish clinical applications targeting miRNAs.

Role of microRNAs in cancers of the female reproductive tract: insights from recent clinical and experimental discovery studies

microRNAs (miRNAs) are small RNA molecules that represent the top of the pyramid of many tumorigenesis cascade pathways as they have the ability to affect multiple, intricate, and still undiscovered downstream targets. Understanding how miRNA molecules serve as master regulators in these important networks involved in cancer initiation and progression open up significant innovative areas for therapy and diagnosis that have been sadly lacking for deadly female reproductive tract cancers. This review will highlight the recent advances in the field of miRNAs in epithelial ovarian cancer, endometrioid endometrial cancer and squamous-cell cervical carcinoma focusing on studies associated with actual clinical information in humans. Importantly, recent miRNA profiling studies have included well-characterized clinical specimens of female reproductive tract cancers, allowing for studies correlating miRNA expression with clinical outcomes. This review will summarize the current thoughts on the role of miRNA processing in unique miRNA species present in these cancers. In addition, this review will focus on current data regarding miRNA molecules as unique biomarkers associated with clinically significant outcomes such as overall survival and chemotherapy resistance. We will also discuss why specific miRNA molecules are not recapitulated across multiple studies of the same cancer type. Although the mechanistic contributions of miRNA molecules to these clinical phenomena have been confirmed using in vitro and pre-clinical mouse model systems, these studies are truly only the beginning of our understanding of the roles miRNAs play in cancers of the female reproductive tract. This review will also highlight useful areas for future research regarding miRNAs as therapeutic targets in cancers of the female reproductive tract.

Integrated microRNA and mRNA transcriptome sequencing reveals the potential roles of miRNAs in stage I endometrioid endometrial carcinoma

Endometrioid endometrial carcinoma (EEC) is the most dominant subtype of endometrial cancer. Aberrant transcriptional regulation has been implicated in EEC. Herein, we characterized mRNA and miRNA transcriptomes by RNA sequencing in EEC to investigate potential molecular mechanisms underlying the pathogenesis. Total mRNA and small RNA were simultaneously sequenced by next generation sequencing technology for 3 pairs of stage I EEC and adjacent non-tumorous tissues. On average, 52,716,765 pair-end 100 bp mRNA reads and 1,669,602 single-end 50 bp miRNA reads were generated. Further analysis indicated that 7 miRNAs and 320 corresponding target genes were differentially expressed in the three stage I EEC patients. Six of all the seven differentially expressed miRNAs were targeting on eleven differentially expressed genes in the cell cycle pathway. Real-time quantitative PCR in sequencing samples and other independent 21 pairs of samples validated the miRNA-mRNA differential co-expression, which were involved in cell cycle pathway, in the stage I EEC. Thus, we confirmed the involvement of hsa-let-7c-5p and hsa-miR-99a-3p in EEC and firstly found dysregulation of hsa-miR-196a-5p, hsa-miR-328-3p, hsa-miR-337-3p, and hsa-miR-181c-3p in EEC. Moreover, synergistic regulations among these miRNAs were detected. Transcript sequence variants such as single nucleotide variant (SNV) and short insertions and deletions (Indels) were also characterized. Our results provide insights on dysregulated miRNA-mRNA co-expression and valuable resources on transcript variation in stage I EEC, which implies the new molecular mechanisms that underlying pathogenesis of stage I EEC and supplies opportunity for further in depth investigations.

MicroRNA-302b-inhibited E2F3 transcription factor is related to all trans retinoic acid-induced glioma cell apoptosis

All-trans retinoic acid (ATRA), a derivative of retinoid, is involved in the onset of differentiation and apoptosis in a wide variety of normal and cancer cells. MicroRNAs (miRNAs) are small non-coding RNAs that control gene expression. Several miRNAs were identified to participate in ATRA-mediated cell differentiation. However, no studies have demonstrated whether miRNA can enhance ATRA cytotoxicity, thereby resulting in cell apoptosis. This study investigated the effects of ATRA-mediated miRNA expression in activating apoptotic pathways in glioblastoma. First, we found that high-dose ATRA treatment significantly reduced cell viability, caspase-dependent apoptosis, endoplasmic reticular (ER) stress activation, and intracellular reactive oxygen species accumulation. From microarray data, miR-302b was analyzed as a putative downstream regulator upon ATRA treatment. Furthermore, we found that ATRA up-regulated miR-302b expression in a dose- and time-dependent manner through retinoic acid receptor α-mediated pathway. Overexpression and knockdown of miR-302b significantly influenced ATRA-mediated cytotoxicity. E2F3, an important transcriptional regulator of glioma proliferation, was validated to be a direct target gene of miR-302b. The miR-302b-reduced E2F3 levels were also identified to be associated with ATRA-mediated glioma cell death. These results emphasize that an ATRA-mediated miR-302b network may provide novel therapeutic strategies for glioblastoma therapy. We propose that high-dose all-trans retinoic acid (ATRA) treatment, a derivative of retinoid, significantly induces glioblastoma cell apoptosis via caspase-dependent apoptosis, endoplasmic reticular (ER) stress, and intracellular reactive oxygen species (ROS) accumulation. The miR-302b overexpression enhanced by ATRA-mediated retinoic acid receptor (RAR)α pathway was also identified. The E2F3 repression, a novel target gene of miR-302b, was involved in ATRA-induced glioblastoma cell cytotoxicity.

Downregulation of miR-638 promotes invasion and proliferation by regulating SOX2 and induces EMT in NSCLC

Aberrant expression of microRNAs has been shown to regulate the biological processes of lung cancer cells. However, the role of miR-638 in the development of NSCLC is still unclear. In this study, low miR-638 and high SOX2 were shown to be associated with tumor size and metastasis of NSCLC patients. Downregulated miR-638 could promote cell invasion and proliferation, while high miR-638 expression reversed the effect. Furthermore, miR-638 could regulate SOX2 by directly binding to its 3'-UTR. Silencing of SOX2 by siRNA partially abolished the enhancement of cell invasion and proliferation induced by downregulated miR-638. Aberrant miR-638 expression could modulate the expression levels of markers of epithelial-to-mesenchymal transition. Our results indicate that miR-638 may play a pivotal role in the development of NSCLC.