MicroRNA-222-3p/GNAI2/AKT axis inhibits epithelial ovarian cancer cell growth and associates with good overall survival

The identification and validation of target genes of IGFBP3 protein in sheep skeletal muscle cells

This study aimed to identify the target genes of IGFBP3（insulin growth factor binding protein）protein and to investigate its target genes effects on the proliferation and differentiation of Hu sheep skeletal muscle cells. IGFBP3 was an RNA-binding protein that regulates mRNA stability. Previous studies have reported that IGFBP3 promotes the proliferation of Hu sheep skeletal muscle cells and inhibits differentiation, but the downstream genes that bind to it have not been reported yet. We predicted the target genes of IGFBP3 through RNAct and sequencing data, and verified by qPCR and RIP（RNA Immunoprecipitation）experiments, and demonstrated GNAI2（G protein subunit alpha i2）as one of the target gene of IGFBP3. After interference with siRNA, we carried out qPCR, CCK8, EdU, and immunofluorescence experiments, and found that GNAI2 can promote the proliferation and inhibit differentiation of Hu sheep skeletal muscle cells. This study revealed the effects of GNAI2 and provided one of the regulatory mechanisms of IGFBP3 protein underlying sheep muscle development.

MicroRNAs, long non-coding RNAs, and circular RNAs and gynecological cancers: focus on metastasis

Gynecologic cancer is a significant cause of death in women worldwide, with cervical cancer, ovarian cancer, and endometrial cancer being among the most well-known types. The initiation and progression of gynecologic cancers involve a variety of biological functions, including angiogenesis and metastasis-given that death mostly occurs from metastatic tumors that have invaded the surrounding tissues. Therefore, understanding the molecular pathways underlying gynecologic cancer metastasis is critical for enhancing patient survival and outcomes. Recent research has revealed the contribution of numerous non-coding RNAs (ncRNAs) to metastasis and invasion of gynecologic cancer by affecting specific cellular pathways. This review focuses on three types of gynecologic cancer (ovarian, endometrial, and cervical) and three kinds of ncRNAs (long non-coding RNAs, microRNAs, and circular RNAs). We summarize the detailed role of non-coding RNAs in the different pathways and molecular interactions involved in the invasion and metastasis of these cancers.

Identification of G protein subunit alpha i2 as a promising therapeutic target of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a global health problem. Its incidence and mortality are increasing. Exploring novel therapeutic targets against HCC is important and urgent. We here explored the expression and potential function of Gαi2 (G protein subunit alpha i2) in HCC. The Cancer Genome Atlas Liver Hepatocellular Carcinoma (TCGA-LIHC) database shows that the number of Gαi2 transcripts in HCC tissues is significantly higher than that in the normal liver tissues. Moreover, Gαi2 overexpression in HCC correlates with poor prognosis of the patients. Gαi2 mRNA and protein expression are also elevated in local HCC tissues and different human HCC cells. In patient-derived primary HCC cells and immortalized HepG2 cells, Gαi2 silencing (by targeted shRNA) or knockout (KO, by the dCas9-sgRNA method) largely suppressed cell proliferation and motility, while inducing cell cycle arrest and caspase-apoptosis activation. Moreover, Gαi2 silencing or KO-induced reactive oxygen species (ROS) production and oxidative injury in primary and HepG2 HCC cells. Whereas different antioxidants ameliorated Gαi2-shRNA-induced anti-HCC cell activity. Using a lentiviral construct, Gαi2 overexpression further augmented proliferation and motility of primary and immortalized HCC cells. Further studies revealed that the binding between the transcription factor early growth response zinc finger transcription factor 1 (EGR1) and Gαi2 DNA promoter was significantly increased in HCC tissues and cells. In vivo, intratumoral injection of Gαi2 shRNA adeno-associated virus significantly hindered HCC xenograft growth in nude mice. Moreover, the growth of Gαi2-KO HCC xenografts in the nude mice was remarkably slow. Gαi2 depletion, oxidative injury, and apoptosis induction were detected in Gαi2-silenced or Gαi2-KO HCC xenografts. Together, overexpressed Gαi2 is required for HCC cell growth in vitro and in vivo, representing as a novel and promising diagnosis marker and therapeutic target of HCC.

G protein inhibitory α subunit 2 is a molecular oncotarget of human glioma

Identification of novel therapeutic oncotargets for human glioma is extremely important. Here we tested expression, potential functions and underlying mechanisms of G protein inhibitory α subunit 2 (Gαi2) in glioma. Bioinformatics analyses revealed that Gαi2 expression is significantly elevated in human glioma, correlating with poor patients' survival, higher tumor grade and wild-type IDH status. Moreover, increased Gαi2 expression was also in local glioma tissues and different glioma cells. In primary and immortalized (A172) glioma cells, Gαi2 shRNA or knockout (KO, by Cas9-sgRNA) potently suppressed viability, proliferation, and mobility, and induced apoptosis. Ectopic Gαi2 overexpression, using a lentiviral construct, further augmented malignant behaviors in glioma cells. p65 phosphorylation, NFκB activity and expression of NFκB pathway genes were decreased in Gαi2-depleted primary glioma cells, but increased following Gαi2 overexpression. There was an increased binding between Gαi2 promoter and Sp1 (specificity protein 1) transcription factor in glioma tissues and different glioma cells. In primary glioma cells Gαi2 expression was significantly reduced following Sp1 silencing, KO or inhibition. In vivo studies revealed that Gαi2 shRNA-expressing AAV intratumoral injection hindered growth of subcutaneous glioma xenografts in nude mice. Moreover, Gαi2 KO inhibited intracranial glioma xenograft in nude mice. Gαi2 depletion, NFκB inhibition and apoptosis induction were observed in subcutaneous and intracranial glioma xenografts with Gαi2 depletion. Together, overexpressed Gαi2 is important for glioma cell growth possibly by promoting NFκB cascade activation.

HDAC5, negatively regulated by miR-148a-3p, promotes colon cancer cell migration

Histone deacetylases (HDACs) are involved in many processes including tumor cell growth and proliferation and regulation of gene expression. To clarify the role of class IIa HDACs in the metastasis of colon adenocarcinoma, we used the class IIa HDAC inhibitor TMP269 and found that it effectively inhibited the migration ability of colon adenocarcinoma cells. Next, we silenced the member of class IIa HDACs and confirmed that the migratory ability of colon adenocarcinoma cells was significantly inhibited by silencing HDAC5 or HDAC7. HDAC5 plays a variety of roles in human cancers. Here, we examined the role of HDAC5 in colon adenocarcinoma. The results indicated that HDAC5 was highly expressed in tumor tissues and negatively correlated with the expression of miR-148a-3p. Moreover, the expression of HDAC5 was correlated with tumor progression. HDAC5 markedly increased the invasion and migration of cancer cells in vitro, an effect that could be inhibited by overexpression of miR-148a-3p. Following an intraperitoneal injection of colon adenocarcinoma cells in athymic nude mice, HDAC5 promoted tumor implant. Together, these findings showed that HDAC5 overexpression in colon adenocarcinoma is consistent with tumor progression and tumor cell migration and the impact of HDAC5 overexpression is reduced by miR-148a-3p.

Enhancer of zeste homolog 2 exerts functions in gastric cancer development via modulating microRNA-222-3p methylation and WEE1 expression

OBJECTIVE

Enhancer of zeste homolog 2 (EZH2) has been studied in gastric cancer (GC), while the role of EZH2 in GC via binding to microRNA (miR)-222-3p remains obscure. This research aims to unravel the regulatory mechanism of EZH2 in GC progression via the modulation of miR-222-3p/WEE1 axis.

METHODS

Initially, EZH2, miR-222-3p and WEE1 levels in GC cells and tissues were examined. Thereafter, vectors altering EZH2, miR-222-3p or WEE1 expression were transfected into GC cells to determine the malignant behaviors involved in tumorigenesis of GC cells. Finally, the targeting relations among EZH2, miR-222-3p and WEE1 were validated.

RESULTS

EZH2 and WEE1 were up-regulated while miR-222-3p was down-regulated in GC tissues and cells. The decreased EZH2, silenced WEE1, or restored miR-222-3p constrained the malignant behaviors involved in tumorigenesis of GC cells. Deletion of miR-222-3p could reverse the effect of silenced EZH2 on suppressing the biological functions of GC cells. EZH2 could bind to the promoter of miR-222-3p, and there was a targeting relationship between miR-222-3p and WEE1.

CONCLUSION

Our study demonstrates that EZH2 promotes GC development via the modulation of miR-222-3p/WEE1 axis, thus providing promising therapeutic targets for GC therapy.

Curcumin Inhibits the Growth and Metastasis of Melanoma via miR-222-3p/SOX10/Notch Axis

Background

The aim of this study was to investigate the effect of curcumin on melanoma and its mechanism.

Methods

Curcumin (0, 0.125, 0.25, or 0.5 mg/ml) was utilized to treat A375 and HT144 cell lines. The MTT analysis was used to confirm the proliferation ability. Wound healing and transwell analysis showed the migration and invasion ability. Immunofluorescence assay was used to demonstrate the effect of curcumin on SOX10 expression. Multiple bioinformatic analysis to confirm the SOX10 associated miRNA. The correlation of miR-222-3p and SOX10 was detected by Luciferase reporter assays. qRT-PCR showed the miR-222-3p level. Western blot analyzed the expression of SOX10, Notch1, and HES1 in melanoma cell treated with or without miR-222-3p inhibitor.

Results

Curcumin could inhibit the proliferation, migration, and invasion of melanoma cells. Furthermore, curcumin repress the expression of SOX10, Notch1, and HES-1, and increase the expression of miR-222-3p. And the miR-222-3p could directly target to SOX10 mRNA to inhibit its expression. In addition, inhibition of miR-222-3p expression reversed the inhibitory effect of curcumin the growth of melanoma cells.

Conclusion

Curcumin enhances the miR-222-3p level to reduce SOX10 expression, and ultimately inactivates the Notch pathway in repressing melanoma proliferation, migration, and invasion.

Hotair promotes the migration and proliferation in ovarian cancer by miR-222-3p/CDK19 axis

Previous studies in our laboratory have reported that miR-222-3p was a tumor-suppressive miRNA in OC. This study aims to further understand the regulatory role of miR-222-3p in OC and provide a new mechanism for its prevention and treatment. We first found that miR-222-3p inhibited the migration and proliferation of OC cells. Then, we observed CDK19 was highly expressed in OC and inversely correlated with miR-222-3p. Besides, we observed that miR-222-3p directly binds to the 3′-UTR of CDK19 and inhibits CDK19 translation, thus inhibiting OC cell migration and proliferation in vitro and repressed tumor growth in vivo. We also observed the inhibitory effect of Hotair on miR-222-3p in OC. In addition, Hotair could promote the proliferation and migration of OC cells in vitro and facilitate the growth and metastasis of tumors in vivo. Moreover, Hotair was positively correlated with CDK19 expression. These results suggest Hotair indirectly up-regulates CDK19 through sponging miR-222-3p, which enhances the malignant behavior of OC. This provides a further understanding of the mechanism of the occurrence and development of OC.

Deregulated miRNA clusters in ovarian cancer: Imperative implications in personalized medicine

Ovarian cancer (OC) is one of the most common and fatal types of gynecological cancer. OC is usually detected at the advanced stages of the disease, making it highly lethal. miRNAs are single-stranded, small non-coding RNAs with an approximate size ranging around 22 nt. Interestingly, a considerable proportion of miRNAs are organized in clusters with miRNA genes placed adjacent to one another, getting transcribed together to result in miRNA clusters (MCs). MCs comprise two or more miRNAs that follow the same orientation during transcription. Abnormal expression of the miRNA cluster has been identified as one of the key drivers in OC. MC exists both as tumor-suppressive and oncogenic clusters and has a significant role in OC pathogenesis by facilitating cancer cells to acquire various hallmarks. The present review summarizes the regulation and biological function of MCs in OC. The review also highlights the utility of abnormally expressed MCs in the clinical management of OC.

Global Proteomic Analysis of Mesenchymal Stem Cells Derived from Human Embryonic Stem Cells via Connective Tissue Growth Factor Treatment under Chemically Defined Feeder-Free Culture Conditions

Stem cells can be applied usefully in basic research and clinical field due to their differentiation and self-renewal capacity. The aim of this study was to establish an effective novel therapeutic cellular source and create its molecular expression profile map to elucidate the possible therapeutic mechanism and signaling pathway. We successfully obtained a mesenchymal stem cell population from human embryonic stem cells (hESCs) cultured on chemically defined feeder-free conditions and treated with connective tissue growth factor (CTGF) and performed the expressive proteomic approach to elucidate the molecular basis. We further selected 12 differentially expressed proteins in CTGF-induced hESC-derived mesenchymal stem cells (C-hESC-MSCs), which were found to be involved in the metabolic process, immune response, cell signaling, and cell proliferation, as compared to bone marrow derived-MSCs(BM-MSCs). Moreover, these up-regulated proteins were potentially related to the Wnt/β-catenin pathway. These results suggest that C-hESC-MSCs are a highly proliferative cell population, which can interact with the Wnt/β-catenin signaling pathway; thus, due to the upregulated cell survival ability or downregulated apoptosis effects of C-hESC-MSCs, these can be used as an unlimited cellular source in the cell therapy field for a higher therapeutic potential. Overall, the study provided valuable insights into the molecular functioning of hESC derivatives as a valuable cellular source.

Spectrum of microRNAs and their target genes in cancer: intervention in diagnosis and therapy

Till date, several groups have studied the mechanism of microRNA (miRNA) biogenesis, processing, stability, silencing, and their dysregulation in cancer. The miRNA coding genes recurrently go through abnormal amplification, deletion, transcription, and epigenetic regulation in cancer. Some miRNAs function as tumor promoters while few others are tumor suppressors based on the transcriptional regulation of target genes. A review of miRNAs and their target genes in a wide range of cancers is attempted in this article, which may help in the development of new diagnostic tools and intervention therapies. The contribution of miRNAs for drug sensitivity or resistance in cancer therapy and opportunities of miRNAs in cancer prognosis or diagnosis and therapy is also presented in detail.

The Profile of MicroRNA Expression and Potential Role in the Regulation of Drug-Resistant Genes in Cisplatin- and Paclitaxel-Resistant Ovarian Cancer Cell Lines

Ovarian cancer is the most lethal gynecological malignancy. The high mortality results from late diagnosis and the development of drug resistance. Drug resistance results from changes in the expression of different drug-resistance genes that may be regulated miRNA. The main aim of our study was to detect changes in miRNA expression levels in two cisplatin (CIS) and two paclitaxel (PAC)—resistant variants of the A2780 drug-sensitive ovarian cancer cell line—by miRNA microarray. The next goal was to identify miRNAs responsible for the regulation of drug-resistance genes. We observed changes in the expression of 46 miRNA that may be related to drug resistance. The overexpression of miR-125b-5p, miR-99a-5p, miR-296-3p, and miR-887-3p and downregulation of miR-218-5p, miR-221-3p, and miR-222-3p was observed in both CIS-resistant cell lines. In both PAC-resistant cell lines, we observed the upregulation of miR-221-3p, miR-222-3p, and miR-4485, and decreased expression of miR-551b-3p, miR-551b-5p, and miR-218-5p. Analysis of targets suggest that expression of important drug-resistant genes like protein Tyrosine Phosphatase Receptor Type K (PTPRK), receptor tyrosine kinase—EPHA7, Semaphorin 3A (SEMA3A), or the ATP-binding cassette subfamily B member 1 gene (ABCB1) can be regulated by miRNA.

miR-222-3p is involved in neural tube closure by directly targeting Ddit4 in RA induced NTDs mouse model

Previously our results showed miR-222-3p was significantly downregulated in retinoic acid-induced neural tube defect (NTD) mouse model through transcriptome. Down-regulation of miR-222-3p may be a causative biomarker in NTDs. In this study, RNA was extracted from mouse embryos at E8.5, E9.5 and E10.5, and the expression level of miR-222-3p was measured by quantitative real-time PCR analysis. The preliminary mechanism of miR-222-3p in NTDs involved in cell proliferation, apoptosis and migration was investigated in mouse HT-22 cell line. The expression of miR-222-3p was significantly decreased at E8.5, E9.5 and E10.5 developed in mouse embryos which were consistent with our transcriptome sequencing. Suppression of miR-222-3p in HT-22 cells resulted in the inhibition of cell proliferation and migration, cell cycle and apoptosis. Moreover, DNA damage transcript 4 (Ddit4) was identified as a direct and functional target of miR-222-3p. miR-222-3p is negatively regulated by Ddit4. The mutation of binding site of Ddit4 3'UTR abrogated the responsiveness of luciferase reporters to miR-222-3p and showed that Ddit4 expression partially attenuated the function of miR-222-3p. We preliminatively confirmed that low expression of miR-222-3p has reduced the expression of β-catenin, TCF4 and other related genes in the Wnt/β-catenin signaling pathway.Collectively, these results demonstrated that miR-222-3p regulates the Wnt/β-catenin signaling pathway through Ddit4 inhibition in HT-22 cells, resulted in cell proliferation and apoptosis imbalance, and thus led to neural tube defects.

The SWI/SNF complex regulates the expression of miR-222, a tumor suppressor microRNA in lung adenocarcinoma

SWitch/Sucrose Non-Fermentable (SWI/SNF) chromatin remodeling complexes are key epigenetic regulators that are recurrently mutated in cancer. Most studies of these complexes are focused on their role in regulating protein-coding genes. However, here, we show that SWI/SNF complexes control the expression of microRNAs. We used a SMARCA4-deficient model of lung adenocarcinoma (LUAD) to track changes in the miRNome upon SMARCA4 restoration. We found that SMARCA4-SWI/SNF complexes induced significant changes in the expression of cancer-related microRNAs. The most significantly dysregulated microRNA was miR-222, whose expression was promoted by SMARCA4-SWI/SNF complexes, but not by SMARCA2-SWI/SNF complexes via their direct binding to a miR-222 enhancer region. Importantly, miR-222 expression decreased cell viability, phenocopying the tumor suppressor role of SMARCA4-SWI/SNF complexes in LUAD. Finally, we showed that the miR-222 enhancer region resides in a topologically associating domain that does not contain any cancer-related protein-coding genes, suggesting that miR-222 may be involved in exerting the tumor suppressor role of SMARCA4. Overall, this study highlights the relevant role of the SWI/SNF complex in regulating the non-coding genome, opening new insights into the pathogenesis of LUAD.

MicroRNA-Based Risk Score for Predicting Tumor Progression Following Radioactive Iodine Ablation in Well-Differentiated Thyroid Cancer Patients: A Propensity-Score Matched Analysis

Simple Summary

The three-tiered American Thyroid Association (ATA) risk stratification helps clinicians tailor decisions regarding follow-up modalities and the need for postoperative radioactive iodine (RAI) ablation and radiotherapy. However, a significant number of well-differentiated thyroid cancers (DTC) progress after treatment. Current follow-up modalities have also been proposed to detect disease relapse and recurrence but have failed to be sufficiently sensitive or specific to detect, monitor, or determine progression. Therefore, we assessed the predictive accuracy of the microRNA-based risk score in DTC with and without postoperative RAI. We confirm the prognostic role of triad biomarkers (miR-2f04, miR-221, and miR-222) with higher sensitivity and specificity for predicting disease progression than the ATA risk score. Compared to indolent tumors, a higher risk score was found in progressive samples and was associated with shorter survival. Consequently, our prognostic microRNA signature and nomogram provide a clinically practical and reliable ancillary measure to determine the prognosis of DTC patients.

Abstract

To identify molecular markers that can accurately predict aggressive tumor behavior at the time of surgery, a propensity-matching score analysis of archived specimens yielded two similar datasets of DTC patients (with and without RAI). Bioinformatically selected microRNAs were quantified by qRT-PCR. The risk score was generated using Cox regression and assessed using ROC, C-statistic, and Brier-score. A predictive Bayesian nomogram was established. External validation was performed, and causal network analysis was generated. Within the eight-year follow-up period, progression was reported in 51.5% of cases; of these, 48.6% had the T1a/b stage. Analysis showed upregulation of miR-221-3p and miR-222-3p and downregulation of miR-204-5p in 68 paired cancer tissues (p < 0.001). These three miRNAs were not differentially expressed in RAI and non-RAI groups. The ATA risk score showed poor discriminative ability (AUC = 0.518, p = 0.80). In contrast, the microRNA-based risk score showed high accuracy in predicting tumor progression in the whole cohorts (median = 1.87 vs. 0.39, AUC = 0.944) and RAI group (2.23 vs. 0.37, AUC = 0.979) at the cutoff >0.86 (92.6% accuracy, 88.6% sensitivity, 97% specificity) in the whole cohorts (C-statistics = 0.943/Brier = 0.083) and RAI subgroup (C-statistic = 0.978/Brier = 0.049). The high-score group had a three-fold increased progression risk (hazard ratio = 2.71, 95%CI = 1.86–3.96, p < 0.001) and shorter survival times (17.3 vs. 70.79 months, p < 0.001). Our prognostic microRNA signature and nomogram showed excellent predictive accuracy for progression-free survival in DTC.

Emerging roles and mechanisms of microRNA‑222‑3p in human cancer (Review)

MicroRNAs (miRNAs/miRs) are a class of small non‑coding RNAs that maintain the precise balance of various physiological processes through regulating the function of target mRNAs. Dysregulation of miRNAs is closely associated with various types of human cancer. miR‑222‑3p is considered a canonical factor affecting the expression and signal transduction of multiple genes involved in tumor occurrence and progression. miR‑222‑3p in human biofluids, such as urine and plasma, may be a potential biomarker for the early diagnosis of tumors. In addition, miR‑222‑3p acts as a prognostic factor for the survival of patients with cancer. The present review first summarizes and discusses the role of miR‑222‑3p as a biomarker for diverse types of cancers, and then focuses on its essential roles in tumorigenesis, progression, metastasis and chemoresistance. Finally, the current understanding of the regulatory mechanisms of miR‑222‑3p at the molecular level are summarized. Overall, the current evidence highlights the crucial role of miR‑222‑3p in cancer diagnosis, prognosis and treatment.

Small Non-Coding-RNA in Gynecological Malignancies

Gynecologic malignancies, which include cancers of the cervix, ovary, uterus, vulva, vagina, and fallopian tube, are among the leading causes of female mortality worldwide, with the most prevalent being endometrial, ovarian, and cervical cancer. Gynecologic malignancies are complex, heterogeneous diseases, and despite extensive research efforts, the molecular mechanisms underlying their development and pathology remain largely unclear. Currently, mechanistic and therapeutic research in cancer is largely focused on protein targets that are encoded by about 1% of the human genome. Our current understanding of 99% of the genome, which includes noncoding RNA, is limited. The discovery of tens of thousands of noncoding RNAs (ncRNAs), possessing either structural or regulatory functions, has fundamentally altered our understanding of genetics, physiology, pathophysiology, and disease treatment as they relate to gynecologic malignancies. In recent years, it has become clear that ncRNAs are relatively stable, and can serve as biomarkers for cancer diagnosis and prognosis, as well as guide therapy choices. Here we discuss the role of small non-coding RNAs, i.e., microRNAs (miRs), P-Element induced wimpy testis interacting (PIWI) RNAs (piRNAs), and tRNA-derived small RNAs in gynecological malignancies, specifically focusing on ovarian, endometrial, and cervical cancer.

miR-222 Suppresses Immature Porcine Sertoli Cell Growth by Targeting the GRB10 Gene Through Inactivating the PI3K/AKT Signaling Pathway

Sertoli cells are central and essential coordinators of spermatogenesis. Accumulating evidence has demonstrated that miRNAs participate in the regulation of Sertoli cell growth. However, the functions and the regulatory mechanisms of miRNAs in Sertoli cells of domestic animals remain largely unknown. Here we report that miR-222 overexpression repressed cell cycle progression and proliferation and promoted the apoptosis of immature porcine Sertoli cells, whereas miR-222 inhibition resulted in the opposite result. miR-222 directly targeted the 3′-UTR of the GRB10 gene and inhibited its mRNA abundance. An siRNA-induced GRB10 knockdown showed similar effects as did miR-222 overexpression on cell proliferation and apoptosis and further attenuated the role of miR-222 inhibition. Furthermore, both miR-222 overexpression and GRB10 inhibition repressed the phosphorylation of PI3K and AKT, the key elements of the PI3K/AKT signaling pathway, whereas GRB10 inhibition offsets the effects of the miR-222 knockdown. Overall, we concluded that miR-222 suppresses immature porcine Sertoli cell growth by targeting the GRB10 gene through inactivation of the PI3K/AKT signaling pathway. This study provides novel insights into the epigenetic regulation of porcine spermatogenesis by determining the fate of Sertoli cells.

HOXC10 promotes tumour metastasis by regulating the EMT-related gene Slug in ovarian cancer

The mortality rate of ovarian cancer is the highest among gynaecological cancers, primarily due to metastatic symptoms. Recent studies have shown that HOX genes are crucial in tumour progression, but the underlying mechanisms remain unclear. Here, HOXC10 expression was examined in ovarian cancer tissues. The function of HOXC10 in ovarian cancer metastasis was investigated in vitroand via intraperitoneal injection in vivo. A total of 158 ovarian cancer patients with adequate records were enrolled for analysis. HOXC10 was associated with metastasis and poor prognosis in ovarian cancer. In vitro, HOXC10 overexpression promoted ovarian cancer cell migration. Moreover, HOXC10 positively regulated Slug expression, altering the migration ability of cancer cells. Furthermore, our study showed that miR-222-3p was a suppressor of HOXC10. In vivo, a decrease in hepatic metastasis was seen in xenograft mice harbouring tumours with stable HOXC10 overexpression after miR-222-3p agomir (an overexpression reagent) injection. This study provides the first evidence that HOXC10 promotes ovarian cancer metastasis by regulating the transcription of the EMT-related gene Slug. Moreover, we found that HOXC10 is regulated by miR-222-3p. These data highlight the crucial role of HOXC10 in enhancing ovarian cancer metastasis and may provide a therapeutic target for ovarian cancer.

Roles of microRNAs in Ovarian Cancer Tumorigenesis: Two Decades Later, What Have We Learned?

Ovarian cancer is one of the top gynecological malignancies that cause deaths among females in the United States. At the molecular level, significant progress has been made in our understanding of ovarian cancer development and progression. MicroRNAs (miRNAs) are short, single-stranded, highly conserved non-coding RNA molecules (19–25 nucleotides) that negatively regulate target genes post-transcriptionally. Over the last two decades, mounting evidence has demonstrated the aberrant expression of miRNAs in different human malignancies, including ovarian carcinomas. Deregulated miRNAs can have profound impacts on various cancer hallmarks by repressing tumor suppressor genes. This review will discuss up-to-date knowledge of how the aberrant expression of miRNAs and their targeted genes drives ovarian cancer initiation, proliferation, survival, and resistance to chemotherapies. Understanding the mechanisms by which these miRNAs affect these hallmarks should allow the development of novel therapeutic strategies to treat these lethal malignancies.

Role of PI3K/AKT pathway in cancer: the framework of malignant behavior

Given that the PI3K/AKT pathway has manifested its compelling influence on multiple cellular process, we further review the roles of hyperactivation of PI3K/AKT pathway in various human cancers. We state the abnormalities of PI3K/AKT pathway in different cancers, which are closely related with tumorigenesis, proliferation, growth, apoptosis, invasion, metastasis, epithelial-mesenchymal transition, stem-like phenotype, immune microenvironment and drug resistance of cancer cells. In addition, we investigated the current clinical trials of inhibitors against PI3K/AKT pathway in cancers and found that the clinical efficacy of these inhibitors as monotherapy has so far been limited despite of the promising preclinical activity, which means combinations of targeted therapy may achieve better efficacies in cancers. In short, we hope to feature PI3K/AKT pathway in cancers to the clinic and bring the new promising to patients for targeted therapies.

Non-canonical signaling pathway of SNAI2 induces EMT in ovarian cancer cells by suppressing miR-222-3p transcription and upregulating PDCD10

Background: Epithelial ovarian cancer (EOC) is one of the most lethal malignancies in women worldwide. Many studies showed the transcription factor SNAI2-induced Epithelial-Mesenchymal Transition (EMT) through inhibiting E-cadherin (E-cad) expression. Our previous study reported that miR-222-3p was an important tumor-suppressive miRNA for EOC development and dissemination. The present study aimed to acquire a deeper mechanistic understanding of the role of miR-222-3p regulation that might contribute to improving current anti-metastasis strategies in EOC. Methods: A variety of techniques were used to measure mRNA and protein expression levels, including quantitative real-time polymerase chain reaction (qRT-PCR), Western blot, immunohistochemical (IHC) staining, and immunofluorescence (IF). Four different microRNA (miRNA) target prediction databases were used to predict the target genes of miR-222. Luciferase assay was performed to determine the direct binding of miR-222-3p to the untranslated region (3'-UTR) of PDCD10. The biological effects of PDCD10 and miR-222-3p were also investigated in vitro by Transwell and wound healing assays, as well as in vivo by a xenograft mice model. Combining UCSC and JASPAR, as well as ENCODE public databases, we predicted that the transcription factor SNAI2 could affect miR-222-3p expression. Luciferase assay was utilized to examine the validity of putative SNAI2 binding sites for miR-222-3p regulation. Chromatin immunoprecipitation (ChIP) was used to explore the SNAI2's occupancy on the miR-222-3p promoter. Results: We observed the inhibitory effect of SNAI2 on miR-222-3p transcription and confirmed the tumor-suppressive function of miR-222-3p both in EOC cells and tissues. PDCD10 was upregulated and inversely correlated with miR-222-3p, both in vitro and in vivo, which was consistent with the information in bioinformatics databases. Furthermore, We observed direct binding of miR-222-3p to the 3'-UTR of PDCD10 and inhibition of PDCD10 translation, which, in turn, inhibited EOC cell migration in vitro and repressed EOC xenografted tumor metastasis in vivo. We found that genetic overexpression of PDCD10 (OE-PDCD10) increased cancer metastasis by down-regulating E-cad and enhancing Vimentin (VIM) thereby inducing EMT and promoting β-catenin/Wnt-mediated cell migration.

Role of microRNAs as Clinical Cancer Biomarkers for Ovarian Cancer: A Short Overview

Ovarian cancer has the highest mortality rate among gynecological cancers. Early clinical signs are missing and there is an urgent need to establish early diagnosis biomarkers. MicroRNAs are promising biomarkers in this respect. In this paper, we review the most recent advances regarding the alterations of microRNAs in ovarian cancer. We have briefly described the contribution of miRNAs in the mechanisms of ovarian cancer invasion, metastasis, and chemotherapy sensitivity. We have also summarized the alterations underwent by microRNAs in solid ovarian tumors, in animal models for ovarian cancer, and in various ovarian cancer cell lines as compared to previous reviews that were only focused the circulating microRNAs as biomarkers. In this context, we consider that the biomarker screening should not be limited to circulating microRNAs per se, but rather to the simultaneous detection of the same microRNA alteration in solid tumors, in order to understand the differences between the detection of nucleic acids in early vs. late stages of cancer. Moreover, in vitro and in vivo models should also validate these microRNAs, which could be very helpful as preclinical testing platforms for pharmacological and/or molecular genetic approaches targeting microRNAs. The enormous quantity of data produced by preclinical and clinical studies regarding the role of microRNAs that act synergistically in tumorigenesis mechanisms that are associated with ovarian cancer subtypes, should be gathered, integrated, and compared by adequate methods, including molecular clustering. In this respect, molecular clustering analysis should contribute to the discovery of best biomarkers-based microRNAs assays that will enable rapid, efficient, and cost-effective detection of ovarian cancer in early stages. In conclusion, identifying the appropriate microRNAs as clinical biomarkers in ovarian cancer might improve the life quality of patients.

Combined MEK and PI3K/p110β Inhibition as a Novel Targeted Therapy for Malignant Mesothelioma Displaying Sarcomatoid Features

Among malignant mesotheliomas (MM), the sarcomatoid subtype is associated with higher chemoresistance and worst survival. Due to its low incidence, there has been little progress in the knowledge of the molecular mechanisms associated with sarcomatoid MM, which might help to define novel therapeutic targets. In this work, we show that loss of PTEN expression is frequent in human sarcomatoid MM and PTEN expression levels are lower in sarcomatoid MM than in the biphasic and epithelioid subtypes. Combined Pten and Trp53 deletion in mouse mesothelium led to nonepithelioid MM development. In Pten;Trp53-null mice developing MM, the Gαi2-coupled receptor subunit activated MEK/ERK and PI3K, resulting in aggressive, immune-suppressed tumors. Combined inhibition of MEK and p110β/PI3K reduced mouse tumor cell growth in vitro. Therapeutic inhibition of MEK and p110β/PI3K using selumetinib (AZD6244, ARRY-142886) and AZD8186, two drugs that are currently in clinical trials, increased the survival of Pten;Trp53-null mice without major toxicity. This drug combination effectively reduced the proliferation of primary cultures of human pleural (Pl) MM, implicating nonepithelioid histology and high vimentin, AKT1/2, and Gαi2 expression levels as predictive markers of response to combined MEK and p110β/PI3K inhibition. Our findings provide a rationale for the use of selumetinib and AZD8186 in patients with MM with sarcomatoid features. This constitutes a novel targeted therapy for a poor prognosis and frequently chemoresistant group of patients with MM, for whom therapeutic options are currently lacking. SIGNIFICANCE: Mesothelioma is highly aggressive; its sarcomatoid variants have worse prognosis. Building on a genetic mouse model, a novel combination therapy is uncovered that is relevant to human tumors.

Role of miR-221/222 in Tumor Development and the Underlying Mechanism

MicroRNA-221/222 (miRNA-221/222, miR-221/222) is a noncoding microRNA which is widely distributed in eukaryotic organisms and deeply involved in the posttranscriptional regulation of gene expressions. According to recent studies, abnormal expressions of miR-221/222 are closely related to the occurrence and development of various kinds of malignant tumors. The role of miR-221/222 in tumor development and their potential molecular mechanism in various cancers, including liver cancer, colorectal cancer, cervical cancer, ovarian cancer, and endometrial carcinoma, are summarized and reviewed in this paper. Moreover, the potential translational biomarker role of abnormal miR-221/222 level in tumor or blood circulation for tumor diagnosis is also discussed.

Prognostic Role of miR-221 and miR-222 Expression in Cancer Patients: A Systematic Review and Meta-Analysis

Background: A wealth of evidence has shown that microRNAs (miRNAs) can modulate specific genes, increasing our knowledge on the fine-tuning regulation of protein expression. miR-221 and miR-222 have been frequently identified as deregulated across different cancer types; however, their prognostic significance in cancer remains controversial. In view of these considerations, we performed an updated systematic review and meta-analysis of published data investigating the effects of miR-221/222 on overall survival (OS) and other secondary outcomes among cancer patients. A systematic search of PubMed, Web of Knowledge, and Cochrane Library databases was performed. Hazard ratios (HRs) and 95% confidence intervals (95% CIs) were used to assess the strength of association. Results: Fifty studies, analyzing 6086 patients, were included in the systematic review. Twenty-five studies for miR-221 and 17 studies for miR-222 which assessed OS were included in the meta-analysis. High expression of miR-221 and miR-222 significantly predicted poor OS (HR: 1.48, 95% CI: 1.14–1.93, p = 0.003 and HR: 1.90, 95% CI: 1.43–2.54, p < 0.001, respectively). Subgroup analysis revealed that the finding on miR-221 was not as robust as the one on miR-222. Furthermore, high miR-222 expression was also associated with worse progression-free survival and disease-free survival pooled with recurrence-free survival. Conclusions: The meta-analysis demonstrated that high expression of miR-222 is associated with poor prognosis in cancer patients, whereas the significance of miR-221 remains unclear. More work is required to fully elucidate the role of miR-221 and miR-222 in cancer prognosis, particularly in view of the limitations of existing results, including the significant heterogeneity and limited number of studies for some cancers.

Methylation-mediated repression of MiR-424/503 cluster promotes proliferation and migration of ovarian cancer cells through targeting the hub gene KIF23

Ovarian cancer is one type of gynecological malignancies with extremely high lethal rate. Abnormal proliferation and metastasis are regarded to play important roles in patients' death, whereas we know little about the underlying molecular mechanisms. Under this circumstance, our current study aims to investigate the role of hub genes in ovarian cancer. Bioinformatics analysis of the data from GEO and analyses of ovarian cancer samples were performed. Then, the results showed that KIF23, a hub gene, was mainly related to cell cycle and positively associated with poor prognosis. Meanwhile, both miR-424-5p and miR-503-5p directly targeted to 3'UTR of KIF23 to suppress the expression of KIF23 and inhibit ovarian cancer cell proliferation and migration. Furthermore, we discovered that miR-424/503 was epigenetically repressed by hypermethylation in the promoter regions, which directly modulated the expression of KIF23 to improve the oncogenic performance of cancer cells in vitro. Together, our research certifies that miR-424/503 cluster is silenced by DNA hypermethylation, which promotes the expression of KIF23, thereby regulating the proliferation and migration of ovarian cancer cells. Interposing this process might be a novel approach in cancer therapy.

β-Cyclodextrin coated and folic acid conjugated magnetic halloysite nanotubes for targeting and isolating of cancer cells

The study developed a simple, effective and inexpensive strategy for capturing, enriching and detecting circulating tumor cells (CTCs) by using folic acid (FA) as the targeting molecule instead of antibodies. This work constructed magnetic halloysite nanotubes (MHNTs) coated with biocompatible β-cyclodextrin (CD), and conjugated to FA via a PEG-Ad linker, to specifically capture the FA receptor (FR)-overexpressing cancer cells. The capture efficiencies of MHNTs@β-CD@Ad-PEG-FA for the Skov3, Hela and A549 cancer cells were 96.3%, 97.0% and 95.6% respectively. In addition, the nanoparticles were able to capture very low numbers of the cancer cells (25-500 cells/mL) from PBS and whole blood, as well as selectively capture the cancer cells over normal HEK 293 T cells. Furthermore, the captured cells were viable and grew normally in vitro, indicating the future potential of downstream analyses. This approach can be adapted for different CTCs, once the tumor-specific surface markers are identified and the efficacy of targeting ligands is established. Taken together, FA-conjugated MHNTs nanoparticles are a highly promising tool for isolating CTCs for the diagnosis and treatment of cancer.

Oncogenic and Tumor-Suppressive Roles of MicroRNAs with Special Reference to Apoptosis: Molecular Mechanisms and Therapeutic Potential

MicroRNAs (miRNAs) are the non-coding class of minute RNA molecules that negatively control post-transcriptional regulation of various functional genes. These miRNAs are transcribed from the loci present in the introns of functional or protein-coding genes, exons of non-coding genes, or even in the 3'-untranslated region (3'-UTR). They have potential to modulate the stability or translational efficiency of a variety of target RNA [messenger RNA (mRNA)]. The regulatory function of miRNAs has been elucidated in several pathological conditions, including neurological (Alzheimer's disease and Parkinson's disease) and cardiovascular conditions, along with cancer. Importantly, miRNA identification in cancer progression and invasion has evolved as an incipient era in cancer treatment. Several studies have shown the influence of miRNAs on various cancer processes, including apoptosis, invasion, metastasis and angiogenesis. In particular, apoptosis induction in tumor cells through miRNA has been extensively studied. The biphasic mode (up- and down-regulation) of miRNA expression in apoptosis and other cancer processes has already been determined. The findings of these studies could be utilized to develop potential therapeutic strategies for the management of various cancers. The present review critically describes the oncogenic and tumor suppressor role of miRNAs in apoptosis and other cancer processes, therapy resistance, and use of their presence in the body fluids as biomarkers.

MicroRNA-182-5p contributes to the protective effects of thrombospondin 1 against lipotoxicity in INS-1 cells

The dysfunction of beta cells serves an important role in the pathogenesis of type 2 diabetes mellitus (T2DM). An improved understanding of the molecular mechanisms underlying beta cell mass and failure will be useful for identifying novel approaches toward preventing and treating this disease. Recent studies have indicated that free fatty acids (FFAs) can cause beta cell dysfunction. In the present study, palmitate (Pal) was used as a FFA and its functions on cell viability and apoptosis were detected. MTT assay and flow cytometry were used and the results revealed that incubation of INS-1 cells with Pal significantly decreased cell viability and increased cell apoptosis. However, a co-incubation with thrombospondin 1 (THBS-1) protected the cells against Pal-induced toxicity. Numerous studies have demonstrated that microRNAs (miRs) are involved in fatty acid-induced beta cell dysfunction. Various studies have reported that miR-182-5p is associated with a number of diseases, including cancer, heart disease, and leukemia. However, to the best of our knowledge miR-182-5p has never been reported to be associated with diabetes. In the present study, miR-182-5p, which is predicted to target the 3'-untranslated region (UTR) of THBS-1, was detected using reverse transcription-quantitative polymerase chain reaction in INS-1 cells in response to Pal. miR-182-5p was significantly increased in Pal-treated cells compared with the control cells. Furthermore, miR-182-5p mimics significantly decreased cell viability and increased Pal-induced apoptosis in INS-1 cells. However, cell viability was increased and Pal-induced apoptosis was decreased in cells that were treated with miR-182-5p inhibitors. The present findings also revealed that overexpression of THBS-1 counteracted the effect of miR-182-5p on cell viability and apoptosis. These results suggested that miR-182-5p is involved in the mechanism of THBS 1 on the modulation of beta cell survival.

Dihydroartemisinin induces apoptosis and inhibits proliferation, migration, and invasion in epithelial ovarian cancer via inhibition of the hedgehog signaling pathway

Dihydroartemisinin (DHA), the primary of artemisinin extracted from the traditional Chinese medicine Artemisia annua, has been used in malaria treatment for a long time. Recently, many studies have indicated that, in addition to antimalarial effects, DHA also exhibits anticancer activity in certain types of neoplasms, including ovarian cancer. However, the precise anti‐ovarian cancer mechanism of DHA is still unclear. Abnormal activation of the hedgehog (Hh) pathway is closely related to tumorigenesis and progression of ovarian cancer. We performed this study to elucidate the effects of DHA on the biological behavior of ovarian cancer cells and to determine its effects on the Hh signaling pathway. CCK8 assays and flow cytometry were used to evaluate the effects of DHA on cell viability and apoptosis in both ovarian cancer cells and HOSEPICs (human ovarian surface epithelial cells) in response to DHA treatment. Transwell membrane chambers were used to analyze the effects of DHA on the migration and invasion of epithelial ovarian cancer cells following treatment with DHA. The impact of DHA on Hh signaling was analyzed by RT‐qPCR and Western blot. DHA significantly inhibited proliferation, migration, and invasion of ovarian cancer cells, and induced apoptosis in vitro. In contrast, DHA had few effects on cell proliferation and apoptosis in HOSEPICs. DHA inhibited the hedgehog signaling pathway. Furthermore, DHA inhibited purmorphamine (Hh signaling pathway agonist)‐induced cell proliferation, cell migration, and cell invasion and the inhibition of apoptosis. Importantly, DHA enhanced GANT61 (hedgehog signaling pathway inhibitor)‐induced apoptosis and the inhibition of cell viability, migratory capacity, and invasive ability. This study demonstrates that DHA inhibits cell viability, migration, and invasion, as well as induces apoptosis in epithelial ovarian cancer through suppression of the Hh signaling pathway.

miR-222 promotes invasion and migration of ovarian carcinoma by targeting PTEN

Ovarian carcinoma is the most lethal of the gynecologic malignancies worldwide. Increasing evidence suggests dysfunction of microRNAs (miRNAs) plays an important role in human cancers. The function of miR-222 was detected in ovarian carcinoma to verify the regulation of phosphatase and tensin homolog (PTEN) by miR-222. miR-222 expression in ovarian carcinoma tissues and cell lines were examined using RT-qPCR. Transwell assay was used to detect miR-222 effects on ovarian carcinoma cell migration and invasion. Western blot analysis and luciferase assays were performed to validate PTEN as miR-222 targets. miR-222 expression was upregulated in ovarian carcinoma tissues and three cell lines (A2780, SKOV-3 and OVCAR-3). Ectopic overexpression of miR-222 in ovarian carcinoma cells was sufficient to promote invasion and migration. PTEN acted as a direct target of miR-222. Overexpression of PTEN inhibited human ovarian carcinoma cell migration and invasion. In summary, our findings suggest that miR-222 plays an important role in promoting ovarian carcinoma cell invasion and migration and miR-222/PTEN may be a novel therapeutic target of miRNA-mediated promotion of cell invasion and migration in ovarian carcinoma.

Upregulation of miR-614 promotes proliferation and inhibits apoptosis in ovarian cancer by suppressing PPP2R2A expression

It has previously been demonstrated that microRNAs (miRNAs) have essential roles and participate in various biological processes by regulating their specific target genes. However, the precise role of miRNAs in ovarian cancer (OC) has not yet been elucidated. The present study demonstrated that miR‑614 expression levels were significantly upregulated in OC tissues and cell lines, whereas decreased miR‑614 demonstrated opposite effects. Furthermore, gain‑of‑function and loss‑of‑function experiments indicated that miR‑614 overexpression promoted cell proliferation and suppressed cell apoptosis. Protein phosphatase 2 regulatory subunit B α, (PPP2R2A) was identified as a direct target of miR‑614 using western blotting and luciferase reporter assays. Notably, silencing of PPP2R2A counter‑acted the effect of miR‑614 inhibitor in OC cell proliferation and cell apoptosis. Overall, the data suggested that miR‑614 promoted cell proliferation and inhibited cell apoptosis of OC cells by targeting PPP2R2A, and may therefore act as a potential target for OC therapy in the future.

miR-205 regulates the proliferation and invasion of ovarian cancer cells via suppressing PTEN/SMAD4 expression

MicroRNAs (miRNAs/miRs) are non-coding RNAs that post-transcriptionally control target genes, and are involved in tumorigenesis, apoptosis, proliferation, invasion, metastasis and chemoresistance. However, data concerning miRNAs in ovarian cancer remain incomplete. The present study aimed to identify miRNAs that affected the malignant phenotype of ovarian cancer, and to analyze their potential mechanisms. The data demonstrated that miR-205 promoted cell proliferation and invasion of ovarian cancer cells via suppressing Phosphatase and tensin homolog (PTEN)/mothers against decapentaplegic homolog 4 (SMAD4) expression. Based on the Cancer Genome Atlas database analysis results, it was identified that miR-205 was significantly upregulated in ovarian cancer tissues and markedly correlated with poor prognosis in patients with ovarian cancer; its abnormal expression was also confirmed in tissues from patients with ovarian cancer by reverse transcription quantitative polymerase chain reaction. Additional Gene Ontology analysis revealed that the target genes of miR-205 were associated with cell proliferation and invasion. Consistent with the database analysis, miR-205 overexpression significantly promoted ovarian cancer cell proliferation and invasion in vitro. To additionally explore the mechanism by which miR-205 was associated with proliferation and invasion of ovarian cancer cells, a protein-protein interaction network was constructed based on miR-205 target genes associated with proliferation and invasion, and it was revealed that PTEN and SMAD4 were key target genes of miR-205. In ovarian cancer tissues, the expression levels of PTEN and SMAD4 were significantly downregulated, suggesting that miR-205 may suppress the expression of PTEN and SMAD4 in vivo. In vitro, miR-205 overexpression markedly suppressed the expression of SMAD4 and PTEN, additionally verifying that PTEN and SMAD4 were the target genes of miR-205 in ovarian cancer cells. These results elucidated the tumor-promoting role of miR-205 and established miR-205 as a potential treatment target for ovarian cancer.

The GAS5/miR-222 Axis Regulates Proliferation of Gastric Cancer Cells Through the PTEN/Akt/mTOR Pathway

BACKGROUND

Several lines of evidence have indicated that growth arrest-specific transcript 5 (GAS5) functions as a tumor suppressor and is aberrantly expressed in multiple cancers. GAS5 was found to be downregulated in gastric cancer (GC) tissues, and ectopic expression of GAS5 inhibited GC cell proliferation.

AIMS

The present study aimed to explore the underlying mechanisms of GAS5 involved in GC cell proliferation.

METHODS

GAS5 and miR-222 expressions in GC cell lines were estimated by quantitative real-time polymerase chain reaction. The effects of GAS5 and miR-222 on GC cell proliferation were assessed by MTT assay and 5-bromo-2-deoxyuridine (BrdU) incorporation assays. The interaction between GAS5 and miR-222 was confirmed by luciferase reporter assay and RNA immunoprecipitation assay. The protein levels of the phosphatase and tensin homolog (PTEN), phosphorylated protein kinase B (Akt) (p-Akt), Akt, phosphorylated mammalian target of rapamycin (mTOR) (p-mTOR), and mTOR were determined by western blot.

RESULTS

GAS5 was downregulated and miR-222 was upregulated in GC cells. GAS5 directly targeted and suppressed miR-222 expression. GAS5 overexpression and miR-222 inhibition suppressed cell proliferation, increased PTEN protein level and decreased p-Akt and p-mTOR protein levels in GC cells while GAS5 knockdown and miR-222 overexpression exhibited the opposite effects. Moreover, mechanistic analyses revealed that GAS5 regulated GC cell proliferation through the PTEN/Akt/mTOR pathway by negatively regulating miR-222.

CONCLUSIONS

GAS5/miR-222 axis regulated proliferation of GC cells through the PTEN/Akt/mTOR pathway, which facilitated the development of lncRNA-directed therapy against this deadly disease.

MicroRNAs in gynecological cancers: Small molecules with big implications

Gynecological cancers (GCs) are often diagnosed at advanced stages, limiting the efficacy of available therapeutic options. Thus, there remains an urgent and unmet need for innovative research for the efficient clinical management of GC patients. Research over past several years has revealed the enormous promise of miRNAs. These small non-coding RNAs can aid in the diagnosis, prognosis and therapy of all major GCs, viz., ovarian cancers, cervical cancers and endometrial cancers. Mechanistic details of the miRNAs-mediated regulation of multiple biological functions are under constant investigation, and a number of miRNAs are now believed to influence growth, proliferation, invasion, metastasis, chemoresistance and the relapse of different GCs. Modulation of tumor microenvironment by miRNAs can possibly explain some of their reported biological effects. miRNA signatures have been proposed as biomarkers for the early detection of GCs, even the various subtypes of individual GCs. miRNA signatures are also being pursued as predictors of response to therapies. This review catalogs the knowledge gained from collective studies, so as to assess the progress made so far. It is time to ponder over the knowledge gained, so that more meaningful pre-clinical and translational studies can be designed to better realize the potential that miRNAs have to offer.

TMED2 promotes epithelial ovarian cancer growth

TMED2 is involved in morphogenesis of the mouse embryo and placenta. We found that expression of TMED2 was higher in epithelial ovarian cancer tissues than normal ovarian tissues. Silencing TMED2 decreased cell proliferation, migration, and invasion. Ectopic expression of TMED2 increased cell proliferation, migration and invasion. Silencing TMED2 inhibited ovarian cancer growth in mice. Silencing TMED2 inhibited IGF2/IGF1R/PI3K/Akt pathway. In agreement, ectopically expressed TMED2 activated IGF2/IGF1R/PI3K/Akt pathway. Mechanistic study revealed that TMED2 directly binds to AKT2, thereby facilitating its phosphorylation. We also found that TMED2 increased IGF1R expression by competing for miR-30a. Thus, TMED2 is oncogenic and a potential target for epithelial ovarian cancer therapy.

Restoration of microRNA-708 sensitizes ovarian cancer cells to cisplatin via IGF2BP1/Akt pathway

A previous study has shown that microRNA-708 (miR-708) functions as a metastasis suppressor in ovarian cancer. In this study, we aimed to explore its implication in regulating cisplatin sensitivity in ovarian cancer cells. To this end, ovarian cancer cells were transfected with miR-708-expressing plasmids or vector before treatment with different concentrations of cisplatin for 48 h. The 50% inhibitory concentration (IC₅₀ ) value was calculated. Apoptosis was analyzed by measuring caspase-3 activity. The target gene mediating the function of miR-708 was identified. Ectopic expression of miR-708 sensitized SKOV3 and A2780 cells to cisplatin, decreasing the IC₅₀ value by two- to threefold. miR-708 overexpression significantly augmented cisplatin-induced apoptosis in ovarian cancer cells, which was coupled with increased caspase-3 activity by two- to fourfold. Similarly, overexpression of miR-708 increased the sensitivity of cisplatin-resistant SKOV3/DDP and A2780/DDP cells to cisplatin-induced toxicity, reducing the IC₅₀ by three- and fivefold, respectively. Delivery of miR-708 enhanced cisplatin-induced elevation in caspase-3 activity in both cisplatin-resistant and parental ovarian cancer cells. Mechanistically, miR-708 downregulated the expression of insulin-like growth factor 2 mRNA-binding protein 1 (IGF2BP1) and suppressed Akt phosphorylation. Silencing of IGF2BP1 markedly blocked the phosphorylation of Akt. Overexpression of IGF2BP1 restored cisplatin resistance and Akt phosphorylation in miR-708-overexpressing ovarian cancer cells. Collectively, miR-708 increases the susceptibility of ovarian cancer cells to cisplatin by targeting IGF2BP1 and inhibiting Akt signaling. Delivery of miR-708 may represent a promising strategy for improving cisplatin chemotherapy.

MicroRNA-153 regulated AKT1 expression and suppressed cell proliferation of epithelial ovarian cancer cells

Epithelial ovarian cancer (EOC) is the most fatal malignancies in females worldwide, with increasing incidence recently in China. MiR-153 was reported to be dysregulated in some human cancers, including EOC. In this study, we explored the roles of miR-153 and its target AKT1 in regulating growth and migration in EOC. Cell proliferation was measured with a CCK-8 assay. Real-time quantitative RT-PCR was performed to investigate expression levels of miR-153. Cell cycle features were analyzed by Flow cytometry system. The direct target gene was confirmed by dual-luciferase reporter assay. We found the expression levels of miR-153 were generally lower in the EOC tissues than in the matched normal tissues. The miR-153 mimics caused significant G0/G1 arrest in A2780 cells. Overexpression of miR-153 suppressed cell proliferation and migration in ovarian cancer. Results of dual-luciferase reporter assay suggested that AKT1 was a direct target of miR-153 in ovarian cancer cells. Overexpression of AKT1 reverses the inhibition effect of miR-153 on cell proliferation. Introduction of miR-153 into EOC cell lines leaded to inhibition of cell proliferation and migration by directly targeting AKT1. MiR-153 may have prognostic or therapeutic value for the future management of ovarian cancer patients.