MiR-718 represses VEGF and inhibits ovarian cancer cell progression

Role of different non-coding RNAs as ovarian cancer biomarkers

Background

Among many gynecological malignancies ovarian cancer is the most prominent and leading cause of female mortality worldwide. Despite extensive research, the underlying cause of disease progression and pathology is still unknown. In the progression of ovarian cancer different non-coding RNAs have been recognized as important regulators. The biology of ovarian cancer which includes cancer initiation, progression, and dissemination is found to be regulated by different ncRNA. Clinically ncRNA shows high prognostic and diagnostic importance.

Results

In this review, we prioritize the role of different non-coding RNA and their perspective in diagnosis as potential biomarkers in the case of ovarian cancer. Summary of some of the few miRNAs involved in epithelial ovarian cancer their expression and clinical features are being provided in the table. Also, in cancer cell proliferation, apoptosis, invasion, and migration abnormal expression of piRNAs are emerging as a crucial regulator hence the role of few piRNAs is being given. Both tRFs and tiRNAs play important roles in tumorigenesis and are promising diagnostic biomarkers and therapeutic targets for cancer. lncRNA has shown a leading role in malignant transformation and potential therapeutic value in ovarian cancer therapy.

Conclusions

Hence in this review we demonstrated the role of different ncRNA that play an important role in serving strong potential as a therapeutic approach for the treatment of ovarian cancer.

A functional screen with metformin identifies microRNAs that regulate metabolism in colorectal cancer cells

Metformin inhibits oxidative phosphorylation and can be used to dissect metabolic pathways in colorectal cancer (CRC) cells. CRC cell proliferation is inhibited by metformin in a dose dependent manner. MicroRNAs that regulate metabolism could be identified by their ability to alter the effect of metformin on CRC cell proliferation. An unbiased high throughput functional screen of a synthetic micoRNA (miRNA) library was used to identify miRNAs that impact the metformin response in CRC cells. Experimental validation of selected hits identified miRNAs that sensitize CRC cells to metformin through modulation of proliferation, apoptosis, cell-cycle and direct metabolic disruption. Among eight metformin sensitizing miRNAs identified by functional screening, miR-676-3p had both pro-apoptotic and cell cycle arrest activity in combination with metformin, whereas other miRNAs (miR-18b-5p, miR-145-3p miR-376b-5p, and miR-718) resulted primarily in cell cycle arrest when combined with metformin. Investigation of the combined effect of miRNAs and metformin on CRC cell metabolism showed that miR-18b-5p, miR-145-3p, miR-376b-5p, miR-676-3p and miR-718 affected glycolysis only, while miR-1181 only regulated CRC respiration. MicroRNAs can sensitize CRC cells to the anti-proliferative effects of metformin. Identifying relevant miRNA targets may enable the design of innovative therapeutic strategies.

Culture Condition of Bone Marrow Stromal Cells Affects Quantity and Quality of the Extracellular Vesicles

Extracellular vesicles (EVs) released by bone marrow stromal cells (BMSCs) have been shown to act as a transporter of bioactive molecules such as RNAs and proteins in the therapeutic actions of BMSCs in various diseases. Although EV therapy holds great promise to be a safer cell-free therapy overcoming issues related to cell therapy, manufacturing processes that offer scalable and reproducible EV production have not been established. Robust and scalable BMSC manufacturing methods have been shown to enhance EV production; however, the effects on EV quality remain less studied. Here, using human BMSCs isolated from nine healthy donors, we examined the effects of high-performance culture media that can rapidly expand BMSCs on EV production and quality in comparison with the conventional culture medium. We found significantly increased EV production from BMSCs cultured in the high-performance media without altering their multipotency and immunophenotypes. RNA sequencing revealed that RNA contents in EVs from high-performance media were significantly reduced with altered profiles of microRNA enriched in those related to cellular growth and proliferation in the pathway analysis. Given that pre-clinical studies at the laboratory scale often use the conventional medium, these findings could account for the discrepancy in outcomes between pre-clinical and clinical studies. Therefore, this study highlights the importance of selecting proper culture conditions for scalable and reproducible EV manufacturing.

A Next-Generation Sequencing of Plasma Exosome-Derived microRNAs and Target Gene Analysis with a Microarray Database of Thermally Injured Skins: Identification of Blood-to-Tissue Interactions at Early Burn Stage

Background

Plasma exosome-derived microRNA (miRNA) profiles following thermal injury and their relationship with gene expression derangements in burned skin remain unexplored. This study focused on the identification of key miRNA-mRNA axes in potential blood-to-tissue interactions at early burn stage.

Methods

Plasma exosomes were obtained from 6 severe burn patients 4–7 days post injury and 6 healthy volunteers. Next-generation sequencing (NGS) of exosomal small RNAs presented the differentially expressed miRNAs (DEMs). Target genes of the DEMs were predicted in the mirDIP database. Dataset GSE8056 was enrolled to acquire differentially expressed genes (DEGs) in burned skin compared to normal skin. Overlap between the DEGs and target genes of the DEMs were focus genes. The protein–protein interaction (PPI) network and enrichment analyses of the focus genes demonstrated hub genes and suggested underlying mechanisms and pathways. The hub genes and upstream DEMs were selected to construct key miRNA-mRNA axes.

Results

The NGS of plasma exosome-derived small RNAs identified 85 DEMs (14 downregulated miRNAs and 71 upregulated miRNAs) with 12,901 predicted target genes. Dataset GSE8056 exhibited 1861 DEGs in partial-thickness burned skins 4–7 days postburn. The overlap between DEGs and target genes of DEMs displayed 1058 focus genes. The top 9 hub genes (CDK1, CCNB1, CCNA2, BUB1B, PLK1, KIF11, AURKA, NUSAP1 and CDCA8) in the PPI network of the focus genes pointed to 16 upstream miRNAs in DEMs, including 4 downregulated miRNAs (hsa-miR-6848-3p, has-miR-4684-3p, has-miR-4786-5p and has-miR-365a-5p) and 12 upregulated miRNAs (hsa-miR-6751-3p, hsa-miR-718, hsa-miR-4754, hsa-miR-6754-3p, hsa-miR-4739, hsa-miR-6739-5p, hsa-miR-6884-3p, hsa-miR-1224-3p, hsa-miR-6878-3p, hsa-miR-6795-3p, hsa-miR-550a-3p, and hsa-miR-550b-3p). A key miRNA-mRNA network in potential blood-to-tissue interactions at early burn stage was therefore constructed.

Conclusion

An NGS and bioinformatic analysis in the study identified key miRNA-mRNA axes in potential blood-to-tissue interactions at early burn stage, suggesting plasma exosome-derived miRNAs may impact on the alteration patterns of gene expressions in a burn wound.

Differentially Expressed Functional LncRNAs in Human Subjects With Metabolic Syndrome Reflect a Competing Endogenous RNA Network in Circulating Extracellular Vesicles

Metabolic syndrome (MetS), a collective cluster of disease risk factors that include dyslipidemia, obesity, inflammation, hypertension, and insulin resistance, affects numerous people worldwide. Accumulating studies have shown that long non-coding RNAs (lncRNAs) serve as competing endogenous RNAs (ceRNAs) to play essential roles in regulating gene expression in various diseases. To explore the role of lncRNAs as ceRNAs in MetS, we examined a MetS-associated network in circulating extracellular vesicles (EVs) collected from the systemic blood of MetS and control patients (n = 5 each). In total, 191 differentially expressed lncRNAs, 1,389 mRNAs, and 138 miRNAs were selected for further analysis. Biological processes and pathway functional enrichment analysis were performed based on the Database for Annotation, Visualization, and Integrated Discovery (DAVID). The lncRNA/mRNA/miRNA ceRNA network was constructed by Cytoscape v3.8 based on the DE-RNAs and included 13 lncRNAs, 8 miRNAs, and 64 mRNAs. MetS patients showed elevated body weight, glucose, blood pressure, insulin, liver injury, and inflammatory marker levels. We found that lncRNAs reflect a ceRNA network that may regulate central cellular processes and complications of MetS, including cancer. These findings suggest that MetS alters the interactions among the ceRNA network components in circulating EVs and that this cargo of circulating EVs may have potential translational ramifications for MetS.

Non-Coding RNAs as Biomarkers of Tumor Progression and Metastatic Spread in Epithelial Ovarian Cancer

Simple Summary

Despite advances in cancer research in recent years, efficient predictive biomarkers of tumor progression and metastatic spread for ovarian cancer are still missing. Therefore, we critically address recent findings in the field of non-coding RNAs (microRNAs and long non-coding RNAs) and DNA methylation in ovarian cancer patients as promising novel biomarkers of ovarian cancer progression.

Abstract

Ovarian cancer is one of the most common causes of death among gynecological malignancies. Molecular changes occurring in the primary tumor lead to metastatic spread into the peritoneum and the formation of distant metastases. Identification of these changes helps to reveal the nature of metastases development and decipher early biomarkers of prognosis and disease progression. Comparing differences in gene expression profiles between primary tumors and metastases, together with disclosing their epigenetic regulation, provides interesting associations with progression and metastasizing. Regulatory elements from the non-coding RNA families such as microRNAs and long non-coding RNAs seem to participate in these processes and represent potential molecular biomarkers of patient prognosis. Progress in therapy individualization and its proper targeting also rely upon a better understanding of interactions among the above-listed factors. This review aims to summarize currently available findings of microRNAs and long non-coding RNAs linked with tumor progression and metastatic process in ovarian cancer. These biomolecules provide promising tools for monitoring the patient’s response to treatment, and further they serve as potential therapeutic targets of this deadly disease.

miRNA profile in ovarian cancer

Ovarian cancer is a gynecological cancer with high mortality and a heterogeneous nature which complicates its early detection and primary prevention. Numerous studies have evaluated expression profile microRNAs (miRNAs) in tissue and serum samples of ovarian cancer patients to find appropriate biomarkers for this malignancy. Functional experiments also verified the oncogenic or suppressor effects of a number of miRNAs. miRNAs exert their role through degradation or inhibition of translation of the target mRNA. Through this regulatory function, they modulate numerous cellular processes which are ultimately associated with carcinogenesis. A number of miRNAs including miR-135a-3p, miR-200c, miR-216a and miR-340 regulate epithelial-mesenchymal transition program thus modulate invasiveness of ovarian cancer cell. Others have been shown to regulate some fundamental pathways in carcinogenesis such as mTOR and PI3K/AKT pathways. Such vast area of function of miRNAs in ovarian cancer has suggested them as putative therapeutic options for future years. In this review, we summarize the recent findings regarding the role of miRNAs in ovarian cancer pathogenesis, their application as biomarkers and the future perspectives of this research area.

MicroRNA‑718 serves a tumor‑suppressive role in non‑small cell lung cancer by directly targeting CCNB1

MicroRNA‑718 (miR‑718) serves crucial roles in tumorigenesis and in the progression of a number of cancers. However, the expression profile, specific functions and mechanisms of action of miR‑718 in non‑small cell lung cancer (NSCLC) are still elusive. The aims of the present study were to quantify the expression of miR‑718, determine its biological roles and elucidate the molecular mechanisms responsible for its activities in NSCLC cells. Reverse transcription‑quantitative PCR was carried out to assess miR‑718 expression in NSCLC tissue samples and cell lines. The Cell Counting Kit‑8 assay, flow cytometry, cell migration and invasion assays, and a tumor xenograft experiment were performed to evaluate the effects of miR‑718 overexpression on the malignant biological behaviors of NSCLC cells. miR‑718 expression was demonstrated to be significantly decreased in NSCLC tissue samples and cell lines. This reduced expression was significantly associated with tumor, node, metastasis stage, tumor size, lymph node metastasis and poor overall survival among patients with NSCLC. Exogenous miR‑718 expression suppressed NSCLC cell proliferation, migration and invasion, and promoted apoptosis in vitro; whereas it hindered tumor growth in vivo. Experiments to elucidate the mechanisms involved revealed that miR‑718 functions by directly targeting cyclin B1 (CCNB1) mRNA. CCNB1 expression was found to be upregulated in NSCLC and inversely correlated with miR‑718 levels. CCNB1 depletion had effects similar to those of miR‑718 overexpression in NSCLC cells. Furthermore, restoration of CCNB1 expression attenuated the tumor‑suppressive effects of miR‑718 overexpression in NSCLC cells. These results indicated that miR‑718 suppressed NSCLC progression in vitro and in vivo by directly targeting CCNB1 mRNA, which may indicate a potential target for the diagnosis and treatment of this fatal disease.

Understanding and Targeting Apoptotic Pathways in Ovarian Cancer

Ovarian cancer cells evade the immune system as well as chemotherapeutic and/or biologic treatments through inherent or acquired mechanisms of survival and drug resistance. Depending on the cell type and the stimuli, this threshold can range from external forces such as blunt trauma to programmed processes such as apoptosis, autophagy, or necroptosis. This review focuses on apoptosis, which is one form of programmed cell death. It highlights the multiple signaling pathways that promote or inhibit apoptosis and reviews current clinical therapies that target apoptotic pathways in ovarian cancer.

Mechanisms of Vasculogenic Mimicry in Ovarian Cancer

Solid tumors carry out the formation of new vessels providing blood supply for growth, tumor maintenance, and metastasis. Several processes take place during tumor vascularization. In angiogenesis, new vessels are derived from endothelial cells of pre-existing vessels; while in vasculogenesis, new vessels are formed de novo from endothelial progenitor cells, creating an abnormal, immature, and disorganized vascular network. Moreover, highly aggressive tumor cells form structures similar to vessels, providing a pathway for perfusion; this process is named vasculogenic mimicry (VM), where vessel-like channels mimic the function of vessels and transport plasma and blood cells. VM is developed by numerous types of aggressive tumors, including ovarian carcinoma which is the second most common cause of death among gynecological cancers. VM has been associated with poor patient outcome and survival in ovarian cancer, although the involved mechanisms are still under investigation. Several signaling molecules have an important role in VM in ovarian cancer, by regulating the expression of genes related to vascular, embryogenic, and hypoxic signaling pathways. In this review, we provide an overview of the current knowledge of the signaling molecules involved in the promotion and regulation of VM in ovarian cancer. The clinical implications and the potential benefit of identification and targeting of VM related molecules for ovarian cancer treatment are also discussed.

miR‑490‑5p regulates the proliferation, migration, invasion and epithelial‑mesenchymal transition of pharyngolaryngeal cancer cells by targeting mitogen‑activated protein kinase kinasekinase 9

MicroRNA (miRNA/miR) has been identified to be a promising tool in treating pharyngolaryngeal cancer. The present study aimed to investigate the role of miR‑490‑5p in the regulation of proliferation, migration, invasion and epithelial‑mesenchymal transition (EMT) of pharyngolaryngeal cancer cells. The data of miR‑490‑5p expression levels of 45 cases were obtained from the People's Hospital of Xinjiang Uygur Autonomous Region, and the prediction of the target of miR‑490‑5p was conducted by bioinformatics and verified using a luciferase assay. Cell viability was determined by cell counting kit‑8. Migration and invasion rates were measured by wound healing test and Transwell apparatus, respectively. Colony formation rate was measured by plate colony formation assay. mRNA and protein levels were determined by quantitative polymerase chain reaction and western blotting, respectively. miR‑490‑5p expression was significantly depressed in primary pharyngolaryngeal cancer tissues and cell lines, leading to an unfavorable prognosis. Evidently, miR‑490‑5p overexpression decreased the cell viabilities of BICR 18 and FaDu cells. Mechanically, miR‑490‑5p could target mitogen‑activated protein kinase kinasekinase 9 (MAP3K9). The overexpression of MAP3K9 could promote cell viability, migration and invasion rates, EMT process and ability of cloning, miR‑490‑5p could target MAP3K9 and further modulate the proliferation, migration, invasion and EMT of pharyngolaryngeal cancer cells. The results of the present study provide a novel entry point to the treatment of pharyngolaryngeal cancer.

miR-718 is involved in malignancy of papillary thyroid cancer through repression of PDPK1

BACKGROUND

MicroRNAs bind the 3' untranslated regions (3'-UTRs) of mRNAs and thereby regulate gene expression post-transcriptionally and play an important role in cancer delvelopment. In the present study, we have explored the role of miR-718 in papillary thyroid cancer cell malignancy.

MATERIALS/METHODS

Here we examined the miRNA expression in human papillary thyroid cancer by RT-PCR. Luciferase activity, RT-PCR and western blot assays were used to confirmed the target of miRNA. MTT, colony formation, transwell, glucose consumption and lactate production assays were performed to analyze papillary thyroid cancer cell function. Western blot for signaling proteins was used to reveal the mechanism.

RESULTS

We first determined that miR-718 mRNA expression levels in PTC samples were reduced. The 3'-UTR of 3-Phosphoinositide Dependent Protein Kinase 1 (PDPK1) was then identified as a target of miR-718. Luciferase assays showed that miR-718 does in fact bind the wild-type PDPK1 3'-UTR. We assessed the effects of miR-718 on p-Akt, Akt, p-mTOR and mTOR expression. We determined that miR-718 negatively regulates their levels, respectively, of Akt-mTOR pathway components. We then assessed the effects of miR-718 on PTC cell behavior. The results revealed that miR-718 negatively regulates PTC cell proliferation, migration, and invasion. In addition, miR-718 was found to inhibit cell glucose metabolism, likely through the Akt-mTOR pathway. Finally, PDPK1 could rescue PTC cell inhibition induced by miR-718.

CONCLUSIONS

The present study strongly suggests that miR-718 inhibits PTC cell proliferation, metastasis, and glucose metabolism by negatively regulating the Akt-mTOR signaling pathway.

Expression pattern of new genes regulating female sex differentiation and in vitro maturational status of oocytes in pigs

The processes underlying maturation of mammalian oocytes are considered crucial for the oocytes ability to undergo monospermic fertilization. The same factors of influence are suggested to impact the development of sex associated characteristics, allowing sex differentiation to progress during embryonic growth. The primary aim of the study was to analyze the gene ontology groups involved in regulation of porcine oocytes' response to endogenous stimuli. The results obtained would indicate potential genes influencing sex differentiation. Additionally, they could help to determine new genetic markers, expression profile of which is substantially regulated during porcine oocytes' in vitro maturation. To achieve that, porcine oocytes were collected for analysis before and after in vitro maturation. Pigs were used as they are a readily available model that presents significant similarity to humans in terms of physiology and anatomy. Microarray analysis of oocytes, before and after in vitro maturation was performed and later validated by RT-qPCR. We have particularly detected and analyzed genes belonging to gene ontology groups associated with hormonal stimulation during maturation of the oocytes, that exhibited significant change in expression (fold change ≥ |2|; p < 0.05) namely "Female sex differentiation" (CCND2, MMP14, VEGFA, FST, INHBA, NR5A1), "Response to endogenous stimulus" (INSR, ESR1, CCND2, TXNIP, TACR3, MMP14, FOS, AR, EGR2, IGFBP7, TGFBR3, BTG2, PLD1, PHIP, UBE2B) and "Response to estrogen stimulus" (INSR, ESR1, CCND2, IHH, TXNIP, TACR3, MMP14). Some of them were characteristic for just one of the described ontologies, while some belonged into multiple ontological terms. The genes were analyzed, with their relation to the processes of interest explained. Overall, the study provides us with a range of genes that might serve as molecular markers of in vitro maturation associated processes of the oocytes. This knowledge might serve as a reference for further studies and, after further validation, as a potentially useful knowledge in assessment of the oocytes during assisted reproduction processes.

Possible Roles of Mitochondrial Dynamics and the Effects of Pharmacological Interventions in Chemoresistant Ovarian Cancer

Ovarian cancer is the major cause of death out of all the gynecologic cancers. The prognosis of this cancer is quite poor since patients only seek treatment when it is at an advanced stage. Any early biomarkers for this cancer are still unknown. Dysregulation of mitochondrial dynamics with associated resistance to apoptosis plays a crucial role in several types of human carcinogenesis, including ovarian cancers. Previous studies showed that increased mitochondrial fission occurred in ovarian cancer cells. However, several pharmacological interventions and therapeutic strategies, which modify the mitochondrial dynamics through the promotion of mitochondrial fission and apoptosis of cancer cells, have been shown to potentially provide beneficial effects in ovarian cancer treatment. Therefore the aim of the present review is to summarize and discuss the current findings from in vitro, in vivo and clinical studies associated with the alteration of mitochondrial dynamics and ovarian cancers with and without interventions.

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Dysregulation of mitochondrial dynamics occurred in ovarian cancer.

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Increased mitochondrial dysregulation may correlate with the increasing degree of chemoresistance in ovarian cancers.

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Drugs-induced mitochondrial fission and apoptosis will be beneficial effect in ovarian cancer therapy.

MicroRNA‑655 inhibits cell proliferation and invasion in epithelial ovarian cancer by directly targeting vascular endothelial growth factor

In recent years, microRNAs (miRNAs/miRs) have been shown to be deregulated in epithelial ovarian cancer (EOC). Their deregulation has been suggested to be involved in EOC formation and progression through the regulation of the expression of numerous cancer‑related genes. Hence, it is of great importance to further determine the detailed roles and underlying mechanisms of miRNAs involved in EOC and to identify novel targets for diagnosis, prognosis and treatment of patients with EOC. In this study, the expression of miR‑655‑3p (miR‑655) was significantly downregulated in EOC tissues and four EOC cell lines. After miR‑655 was restored, functional assays revealed that cellular proliferation and invasion were considerably reduced in EOC. Additionally, vascular endothelial growth factor (VEGF) A was identified as a direct target gene of miR‑655 in EOC cells. Furthermore, VEGF knockdown could mimic the tumour‑suppressive roles of miR‑655 overexpression in EOC cells. Moreover, the introduction of VEGF abrogated the effects of miR‑655‑induced proliferation and invasion inhibition in EOC cells. Altogether, these findings indicated that miR‑655 may inhibit EOC cell proliferation and invasion by repressing VEGF. Thus, the miR‑655/VEGF pathway could serve as a novel therapeutic target for patients with EOC.

MicroRNA-30b controls endothelial cell capillary morphogenesis through regulation of transforming growth factor beta 2

The importance of microRNA (miRNA) to vascular biology is becoming increasingly evident; however, the function of a significant number of miRNA remains to be determined. In particular, the effect of growth factor regulation of miRNAs on endothelial cell morphogenesis is incomplete. Thus, we aimed to identify miRNAs regulated by pro-angiogenic vascular endothelial growth factor (VEGF) and determine the effects of VEGF-regulated miRNAs and their targets on processes important for angiogenesis. Human umbilical vein endothelial cells (HUVECs) were thus stimulated with VEGF and miRNA levels assessed using microarrays. We found that VEGF altered expression of many miRNA, and for this study focused on one of the most significantly down-regulated miRNA in HUVECs following VEGF treatment, miR-30b. Using specific miRNA mimics, we found that overexpression of miR-30b inhibited capillary morphogenesis in vitro, while depletion of endogenous miR-30b resulted in increased capillary morphogenesis indicating the potential significance of down-regulation of miR-30b as a pro-angiogenic response to VEGF stimulation. MiR-30b overexpression in HUVEC regulated transforming growth factor beta 2 (TGFβ2) production, which led to increased phosphorylation of Smad2, indicating activation of an autocrine TGFβ signaling pathway. Up-regulation of TGFβ2 by miR-30b overexpression was found to be dependent on ATF2 activation, a transcription factor known to regulate TGFβ2 expression, as miR-30b overexpressing cells exhibited increased levels of phosphorylated ATF2 and depletion of ATF2 inhibited miR-30b-induced TGFβ2 expression. However, miR-30b effects on ATF2 were indirect and found to be via targeting of the known ATF2 repressor protein JDP2 whose mRNA levels were indirectly correlated with miR-30b levels. Increased secretion of TGFβ2 from HUVEC was shown to mediate the inhibitory effects of miR-30b on capillary morphogenesis as treatment with a neutralizing antibody to TGFβ2 restored capillary morphogenesis to normal levels in miR-30b overexpressing cells. These results support that the regulation of miR-30b by VEGF in HUVEC is important for capillary morphogenesis, as increased miR-30b expression inhibits capillary morphogenesis through enhanced expression of TGFβ2.

microRNA-488 inhibits chemoresistance of ovarian cancer cells by targeting Six1 and mitochondrial function

Dysregulation of miR-488 has been implicated in several human cancers. In this study, we aim to explore its expression and biological function in ovarian cancers. We found miR-488 expression was downregulated in ovarian cancer tissues. Using CCK8 and colony formation assay showed that miR-488 inhibited SKOV3 cell proliferation and colony formation, with downregulation of cyclin D1 and cyclin E protein. While miR-488 inhibitor promoted OVCAR3 cell growth and colony formation. Cell viability and Annexin V/PI staining showed that miR-488 downregulated cell survival and increased apoptosis rate when treated with cisplatin and paclitaxel. Further experiments using MitoTracker and JC-1 staining indicated that miR-488 regulated mitochondrial fission/fusion balance and inhibited mitochondrial membrane potential, with p-Drp1, Drp1 and Fis1 downregulation. Luciferase reporter assay showed that Six1 is a target of miR-488. We also found a negative association between Six1 and miR-488 in ovarian cancer tissues. In addition, Six1 overexpression induced mitochondrial fission and increased mitochondrial potential, with upregulation of Drp1 signaling. Six1 depletion showed the opposite effects. Restoration of Six1 in SKOV3 cells rescued decreased p-Drp1 and Drp1 expression induced by miR-488 mimic. Six1 plasmid also reversed the effects of miR-488 on chemoresistance and apoptosis. Taken together, the present study showed that, by targeting Six1, miR-488 inhibits chemoresistance of ovarian cancer cells through regulation of mitochondrial function.

Cancer Hallmarks and MicroRNAs: The Therapeutic Connection

Human cancers are characterized by a number of hallmarks, including sustained proliferative signaling, evasion of growth suppressors, activated invasion and metastasis, replicative immortality, angiogenesis, resistance to cell death, and evasion of immune destruction. As microRNAs (miRNAs) are deregulated in virtually all human cancers, they show involvement in each of the cancer hallmarks as well. In this chapter, we describe the involvement of miRNAs in cancer from a cancer hallmarks and targeted therapeutics point of view. As no miRNA-based cancer therapeutics are available to date, and the only clinical trial on miRNA-based cancer therapeutics (MRX34) was terminated prematurely due to serious adverse events, we are focusing on protein-coding miRNA targets for which targeted therapeutics in oncology are already approved by the FDA. For each of the cancer hallmarks, we selected major protein-coding players and describe the miRNAs that target them.

Involvement of microRNA-718, a new regulator of EGR3, in regulation of malignant phenotype of HCC cells

OBJECTIVE

Hepatocellular carcinoma (HCC) is still one of the most common death-related malignancies worldwide. Because the way onset and progression are hidden most, HCC diagnoses are made at an advanced stage, when they are unsuitable for surgical resection. MicroRNAs are a class of small non-coding RNAs, participating in many aspects of cancers. In this study, we tried to establish the role of microRNA-718 (miR-718) in the malignant phenotype of HCC cells and its possible role in HCC diagnosis.

METHODS

Here we first used a methylthiazolyldiphenyl-tetrazolium bromide (MTT) assay, Transwell migration and invasion assays, and colony formation assay to evaluate the impact of miR-718 on the malignant phenotypes of HCC cells. Then, we used bioinformatic methods to predict the target gene of miR-718 and used green fluorescence protein (GFP) reporter assay, Western blot, and quantitative real-time polymerase chain reaction (qRT-PCR) to validate the regulation relationship. Finally, we determined the role of the target gene in the HCC phenotype.

RESULTS

We found that the expression of miR-718 was significantly reduced in various HCC cell lines and HCC tissues. Re-expression of miR-718 significantly reduced the cellular viability and colony formation ability as well as inhibited the migration and invasion abilities of HCC cell lines. Early growth response protein 3 (EGR3) is a direct target of miR-718 and is negatively regulated by miR-718. EGR3 could increase the viability and proliferation of HCC cells, and promot the migration and invasion of HCC cells.

CONCLUSIONS

miR-718 acts as a tumor suppressive microRNA in HCC via regulating the expression of EGR3, which may provide a new diagnostic marker and treatment target for HCC.

Specific circulating microRNA signature of bicuspid aortic valve disease

BACKGROUND

We aimed to determine the circulating miRNA expression profile associated with BAV and aortic dilation to provide diagnostic and prognostic biomarkers for BAV and/or aortic dilation.

METHODS AND RESULTS

We applied a miRNome-wide microarray approach using plasma samples (n = 24) from healthy tricuspid aortic valve individuals, BAV patients and BAV patients with aortic dilation to compare and identify the specific miRNAs associated with BAV and aortic dilation. In a second stage, the expression patterns of the miRNA candidates were validated by RT-qPCR in an independent cohort (n = 43). The miRNA microarray data and RT-qPCR analyses revealed that the expression levels of circulating miR-122, miR-130a and miR-486 are significantly influenced by the morphology of the aortic valve (bicuspid/tricuspid) and could be functionally involved in the regulation of TGF-β₁ signalling. Furthermore, the expression pattern of miR-718 in the plasma was strongly influenced by dilation of the ascending aorta. miR-718 expression was inversely correlated with the aortic diameter (R = -0.63, p = 3.1 × 10^-5) and was an independent predictor of aortic dilation (β = -0.41, p = 0.022). The genes targeted by miR-718 are involved in the regulation of vascular remodelling.

CONCLUSIONS

We propose that miR-122, miR-130a, miR-486 and miR-718 are new molecular features associated with BAV and aortic dilation principally by the activation of TGF-β₁ pathway and vascular remodelling mediated by VEGF signalling pathways.

Transcriptional network in ovarian cancer cell line SKOV3 treated with Pinellia pedatisecta Schott extract

Ovarian cancer is the most lethal disease among the malignant tumors of female reproductive organs. Few successful therapeutic options exist for patients with ovarian cancer. The common therapeutic methods are surgical operation, chemotherapy, radiotherapy, and combination of these treatments. In recent years, studies have indicated that Pinellia pedatisecta Schott (PPS), a traditional Chinese medicine, could inhibit tumor growth. In this study, we demonstrated that PPS extract could induce apoptosis in SKOV3 cells in a dose- and time-dependent manner. We further conducted transcriptome sequencing on PPS extract-treated SKOV3 cells along with controls, and identified 1,754 transcripts whose expression differs at least 3-fold over the controls. These differentially expressed transcripts include the apoptosis-related genes such as the caspase family members, and were significantly enriched in steroid biosynthesis in the KEGG pathway database compared with the transcriptome background. Most of the differentially expressed transcripts from this pathway were upregulated in PPS extract-treated cell line, indicating that PPS extract-induced apoptosis was accompanied by increased steroid biosynthesis (e.g. zymosterol). These results suggest that PPS extract could be a new cytostatic therapeutic agent for ovarian cancer.

Guanine-Rich Sequences Are a Dominant Feature of Exosomal microRNAs across the Mammalian Species and Cell Types

Exosome is an extracellular vesicle released from multivesicular endosomes and contains micro (mi) RNAs and functional proteins derived from the donor cells. Exosomal miRNAs act as an effector during communication with appropriate recipient cells, this can aid in the utilization of the exosomes in a drug delivery system for various disorders including malignancies. Differences in the miRNA distribution pattern between exosomes and donor cells indicate the active translocation of miRNAs into the exosome cargos in a miRNA sequence-dependent manner, although the molecular mechanism is little known. In this study, we statistically analyzed the miRNA microarray data and revealed that the guanine (G)-rich sequence is a dominant feature of exosome-dominant miRNAs, across the mammalian species-specificity and the cell types. Our results provide important information regarding the potential use of exosome cargos to develop miRNA-based drugs for the treatment of human diseases.

Lysophosphatidic acid signaling in ovarian cancer

Lysophosphatidic acid (LPA) is a bioactive phospholipid that is involved in signal transduction between cells. Plasma and ascites levels of LPA are increased in ovarian cancer patients even in the early stages and thus LPA is considered as a potential diagnostic marker for this disease. This review presents the current knowledge regarding LPA signaling in epithelial ovarian cancer. LPA stimulates proliferation, migration and invasion of ovarian cancer cells through regulation of vascular endothelial growth factor, matrix metalloproteinases, urokinase plasminogen activator, interleukin-6, interleukin-8, CXC motif chemokine ligand 12/CXC receptor 4, COX2, cyclin D1, Hippo-Yap and growth-regulated oncogene α concentrations. In this article, all of these targets and signal pathways involved in LPA influence are described.

New ways to successfully target tumor vasculature in ovarian cancer

PURPOSE OF REVIEW

The aim of this article was to review the recent literature on potential therapeutic strategies for overcoming resistance to antivascular endothelial growth factor drugs in ovarian cancer.

RECENT FINDINGS

Although clinical benefits of antivascular endothelial growth factor therapy were observed in ovarian cancer treatment trials, this use yielded only modest improvement in progression-free survival and, with the exception of cediranib, no effect on overall survival. Adaptive resistance and escape from antiangiogenesis therapy is likely a multifactorial process, including induction of hypoxia, vascular modulators, and immune response. New drugs targeting the tumor vasculature or other components of the surrounding microenvironment have shown promising results.

SUMMARY

When to start and end antiangiogenesis therapy and the choice of optimal treatment combinations remain controversial. Further evaluation of personalized novel angiogenesis-based therapy is warranted. Defining the critical interaction of these agents and pathways and the appropriate predictive markers will become an increasingly important objective for effective treatment.

EZH2 promotes angiogenesis through inhibition of miR-1/Endothelin-1 axis in nasopharyngeal carcinoma

Emerging evidence clearly indicates that EZH2 plays a crucial role in tumor angiogenesis. However, the role of EZH2 in angiogenesis is still unknown in nasopharyngeal carcinoma (NPC). We here showed that the elevated EZH2 level was closely associated with an aggressive and poor prognostic phenotype, and was positively correlated with microvessel density (MVD) in NPC tissues. Functional studies showed that EZH2 upregulation promoted cell proliferation, migration and tubule formation of endothelial cells, and knockdown of EZH2 suppressed tumor growth, metastasis and angiogenesis in vivo. Mechanistic investigations revealed that EZH2 inhibited miR-1 transcription via promoter binding activity, leading to enhanced expression of Endothelin-1 (ET-1) which is suppressed by miR-1 targeting of ET-1 3'UTR. Furthermore, knockdown of EZH2 or overexpression of miR-1 exerted anti-angiogenic effect on NPC cells. More importantly, the neutralizing antibody against ET-1 significantly abrogated the pro-angiogenic effect of EZH2, and forced expression of ET-1 rescued the anti-angiogenic effect induced by EZH2 knockdown. In clinical specimens, ET-1 was widely overexpressed and associated with clinical stage and MVD. Taken together, our results identify a novel signaling pathway involved in NPC angiogenesis, and also suggest that EZH2-miR-1-ET-1 axis represents multiple potential therapeutic targets for NPC.