MiR-219-5p inhibits growth and metastasis of ovarian cancer cells by targeting HMGA2

The IGF2BP2-lncRNA TRPC7-AS1 axis promotes hepatocellular carcinoma cell proliferation and invasion

Hepatocellular carcinoma(HCC) is one of the most common tumors in the world. Human insulin-like growth factor 2(IGF2) mRNA binding protein 2(IGF2BP2) plays an important role in the progression of hepatocellular carcinoma. Additionally, long non-coding RNA(lncRNA) has been confirmed as a key regulator of hepatocellular carcinoma occurrence. However, the function of TRPC7-AS1 has not been verified in hepatocellular carcinoma. The research results revealed that high IGF2BP2 expression was associated with a decreased survival rate in patients with hepatocellular carcinoma. Furthermore, IGF2BP2 knockdown inhibited and IGF2BP2 overexpression promoted the cell proliferation and invasion of hepatocellular carcinoma cells. The research illuminated that IGF2BP2 regulated the expression of TRPC7-AS1, and a correlation was observed between IGF2BP2 and TRPC7-AS1 expression. TRPC7-AS1 silencing repressed and its overexpression promoted the progression of hepatocellular carcinoma. After silencing or overexpressing TRPC7-AS1, the expression of the high-mobility group AT-hook 2 (HMGA2) gene decreased or increased, respectively. IGF2BP2 enhanced the expression of TRPC7-AS1 and thus affected the expression of HMGA2, thereby promoting hepatocellular carcinoma progression.

MicroRNA-23a-3p overexpression represses proliferation and accelerates apoptosis of granular cells in polycystic ovarian syndrome by targeting HMGA2

OBJECTIVE

Granular cells (GCs) are involved in polycystic ovarian syndrome (PCOS) progression. MicroRNA (miR)-23a downregulation is linked to PCOS development. Therefore, this research explored the influences of miR-23a-3p on GC proliferation and apoptosis in PCOS.

METHODS

Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and western blotting were conducted to examine miR-23a-3p and HMGA2 expression in GCs of patients with PCOS. Then, miR-23a-3p and/or HMGA2 expression was altered in GCs (KGN and SVOG), after which miR-23a-3p, HMGA2, Wnt2, and β-catenin expression, GC viability, and GC apoptosis were measured by RT-qPCR and western blotting, MTT assay, and flow cytometry, respectively. A dual-luciferase reporter gene assay was utilized to assess the targeting relationship between miR-23a-3p and HMGA2. Finally, GC viability and apoptosis were tested after the combined treatment of miR-23a-3p mimic and pcDNA3.1-HMGA2.

RESULTS

miR-23a-3p was poorly expressed but HMGA2 was overexpressed in GCs of patients with PCOS. Mechanistically, HMGA2 was negatively targeted by miR-23a-3p in GCs. Furthermore, miR-23a-3p inhibition or HMGA2 upregulation elevated viability and reduced apoptosis of KGN and SVOG cells, along with increased Wnt2 and β-catenin expression. In KNG cells, HMGA2 overexpression abrogated the impacts of miR-23a-3p overexpression on GC viability and apoptosis.

CONCLUSIONS

Collectively, miR-23a-3p decreased HMGA2 expression to block the Wnt/β-catenin pathway, thereby depressing viability and facilitating apoptosis of GCs.

HMGA2 regulation by miRNAs in cancer: affecting cancer hallmarks and therapy response

High mobility group A 2 (HMGA2) is a protein that modulates the structure of chromatin in the nucleus. Importantly, aberrant expression of HMGA2 occurs during carcinogenesis, and this protein is an upstream mediator of cancer hallmarks including evasion of apoptosis, proliferation, invasion, metastasis, and therapy resistance. HMGA2 targets critical signaling pathways such as Wnt/β-catenin and mTOR in cancer cells. Therefore, suppression of HMGA2 function notably decreases cancer progression and improves outcome in patients. As HMGA2 is mainly oncogenic, targeting expression by non-coding RNAs (ncRNAs) is crucial to take into consideration since it affects HMGA2 function. MicroRNAs (miRNAs) belong to ncRNAs and are master regulators of vital cell processes, which affect all aspects of cancer hallmarks. Long ncRNAs (lncRNAs) and circular RNAs (circRNAs), other members of ncRNAs, are upstream mediators of miRNAs. The current review intends to discuss the importance of the miRNA/HMGA2 axis in modulation of various types of cancer, and mentions lncRNAs and circRNAs, which regulate this axis as upstream mediators. Finally, we discuss the effect of miRNAs and HMGA2 interactions on the response of cancer cells to therapy. Regarding the critical role of HMGA2 in regulation of critical signaling pathways in cancer cells, and considering the confirmed interaction between HMGA2 and one of the master regulators of cancer, miRNAs, targeting miRNA/HMGA2 axis in cancer therapy is promising and this could be the subject of future clinical trial experiments.

miR-219-5p attenuates cisplatin resistance of ovarian cancer by inactivating Wnt/β-catenin signaling and autophagy via targeting HMGA2

Our previous study confirmed that miR-219-5p inhibits the progression of ovarian cancer (OC) by targeting high mobility group AT-hook 2 (HMGA2), while the role of miR-219-5p on the chemoresistance of OC is unclear. HMGA2 and miR-219-5p expression in OC tumors and various types of OC cells were determined by reverse transcription-quantitative PCR (RT-qPCR) and western blotting. The miRNA profiles in A2780 and cisplatin-resistant A2780 cells were investigated via bulk miRNA sequencing, and the interactions of miR-219-5p and HMGA2 were determined by luciferase reporter activity assay. Cell function was verified through Cell Counting Kit-8, invasion assay, wound-healing, and TUNEL assays. HMGA2 level is highly expressed in cisplatin-resistant OC cell lines compared to normal OC cells, while the expression trend of miR-219-5p is the opposite. In addition, we found that miR-219-5p is one of the miRNAs that have the most significant reduction in levels in the cisplatin-resistant A2780/DDP cell line compared to A2780 cells. Then, we reveal that miR-219-5p directly targets HMGA2 in cisplatin-resistant OC cells, and upregulation of miR-219-5p significantly reduces the resistance of OC cells to cisplatin both in vitro and in vivo. Finally, our results suggest that Wnt/β-catenin signaling and autophagy pathway is involved in the role of miR-219-5p/HMGA2 on resistance of OC cells to cisplatin via gain-of-function experiments. Collectively, the present study shows that miR-219-5p decreases the resistance of OC cells to cisplatin via Wnt/β-catenin signaling and autophagy by regulating HMGA2, which provides a feasible solution for the resistance of OC to chemotherapy.

MiR-219a-5p Inhibits Michigan Cancer Foundation-7 (MCF-7) Cell Migration by Regulating Zinc Finger E-Box Binding Homeobox 1 (ZEB1) Expression

The potential role of miR-219a-5p in the migration of breast cancer has not been fully elucidated. In this study, bioinformatic analysis revealed that high miR-219a-5p expression in breast cancer tissue was associated with good survival of breast cancer patients. RT-qPCR analysis indicated that miR-219a-5p expression is significantly lower in MDA-MB-231 triple-negative breast cancer (TNBC) cells. In addition, pre-miR-219a overexpression inhibited MCF-7 cell migration and inhibited ZEB1, Twist1 and vimentin expression but promoted the expression of E-cadherin. Moreover, miR-219a-5p mimics inhibited MCF-7 cell migration, whereas MCF-7 cell migration was promoted by the miR-219a-5p inhibitor. Furthermore, miR-219a-5p was found to inhibit the translation of ZEB1 expression by targeting the 5′-ACAAUCA-3′ motif of the ZEB1 3′UTR, and the binding motif is conserved in multiple species. ZEB1 overexpression rescued the inhibition of cell migration induced by miR-219a-5p. Finally, an inverse correlation of miR-219a-5p and ZEB1 expression was observed in four breast cancer cell lines. Thus, miR-219a-5p inhibits MCF-7 cell migration by regulating ZEB1 expression, and ZEB1 is the target gene of miR-219a-5p.

Genetic Polymorphisms in microRNA Genes Targeting PI3K/Akt Signal Pathway Modulate Cervical Cancer Susceptibility in a Chinese Population

Polymorphisms in microRNA (miRNA) genes could influence the expression of miRNAs that regulate the PI3K/Akt signalling pathway and play crucial roles in cancer susceptibility. To investigate the association of single nucleotide polymorphisms (SNPs) in miRNA genes of PI3K/Akt with cervical intraepithelial neoplasia (CIN) and cervical cancer (CC), nine SNPs located in miRNA genes were selected for genotyping, and the association of these SNPs with CIN and CC risk was evaluated. A total of 1,402 participants were enrolled in the current study, including 698 healthy individuals in the control group, 431 patients with CC, and 273 patients with CIN. Nine SNPs in miRNA genes (rs107822 in miR-219a, rs10877887 in let-7i, rs2292832 in miR-149, rs353293 in miR-143, rs3746444 in miR-499, rs3803808 in miR-132, rs4078756 in miR-10b, rs629367 in let-7a, and rs7372209 in miR-26a) were genotyped using MassArray, and the association of these SNPs with CIN and CC were analysed. The results showed that the frequencies of rs107822 in miR-219a and rs2292832 in miR-149 were significantly different between the control and CC groups (p < 0.005). The C allele of rs107822 in miR-219a was associated with an increased risk of CC (OR = 1.29, 95%CI:1.09–1.54) whereas the C allele of rs2292832 in miR-149 was associated with a decreased risk of CC (OR = 0.77, 95%CI:0.64–0.92). The results of inheritance model analysis showed that the best-fit inheritance models for rs107822 and rs2292832 were log-additive. The 2CC + CT genotype of rs107822 could be a risk factor for CC when compared with the TT genotype (OR = 1.28, 95%CI:1.08–1.51). The 2CC + CT genotype of rs2292832 could be a protective factor against CC when compared with the TT genotype (OR = 0.76, 95%CI:0.64–0.92). However, no association of these SNPs with CIN was found in the current study. Our results suggest that rs107822 in the promoter region of miR-219a and rs2292832 in pre-miR-149 region are associated with the risk of CC.

Effects of HMGA2 gene silencing on cell cycle and apoptosis in the metastatic renal carcinoma cell line ACHN

Objective

To explore the role of high mobility group AT-hook 2 (HMGA2) in the regulation of the cell cycle and apoptosis.

Methods

The renal carcinoma cell line ACHN was transiently transfected with small interfering RNA to knock down the expression of the HMGA2 gene. Cell cycle analysis was undertaken using flow cytometry. The mRNA and protein levels of HMGA2, E2F transcription factor 1 (E2F1), cyclin D1, cyclin dependent kinase 6 (CDK6), B-cell lymphoma-2 (Bcl-2), caspase-3 and caspase-9 were analysed using reverse transcription quantitative real-time polymerase chain reaction and Western blot analysis.

Results

The mRNA and protein levels of HMGA2 were significantly higher in renal carcinoma cell lines compared with the human renal proximal tubular epithelial cell line HKC. After HMGA2 gene-specific silencing, more cells entered the G₀/G₁ phase, while fewer cells entered the G₂/M phase; and the cells exhibited early and late apoptosis. HMGA2 gene-specific silencing significantly reduced the mRNA and protein levels of E2F1, cyclin D1, CDK6 and Bcl-2; and increased the mRNA and protein levels of caspase-3 and caspase-9.

Conclusion

The HMGA2 gene may be involved in the tumorigenesis and development of renal cancer, thus inhibiting HMGA2 gene expression might provide a potential therapeutic target in the future.

The Role of MiRNA in Cancer: Pathogenesis, Diagnosis, and Treatment

Cancer is also determined by the alterations of oncogenes and tumor suppressor genes. These gene expressions can be regulated by microRNAs (miRNA). At this point, researchers focus on addressing two main questions: "How are oncogenes and/or tumor suppressor genes regulated by miRNAs?" and "Which other mechanisms in cancer cells are regulated by miRNAs?" In this work we focus on gathering the publications answering these questions. The expression of miRNAs is affected by amplification, deletion or mutation. These processes are controlled by oncogenes and tumor suppressor genes, which regulate different mechanisms of cancer initiation and progression including cell proliferation, cell growth, apoptosis, DNA repair, invasion, angiogenesis, metastasis, drug resistance, metabolic regulation, and immune response regulation in cancer cells. In addition, profiling of miRNA is an important step in developing a new therapeutic approach for cancer.

Down-regulation of miR-219-5p increase the risk of cancer-related mortality in patients with prostate cancer

INTRODUCTION

Prostate cancer is a common malignancy in men that is difficult to treat and carries a high risk of death. miR-219-5p is expressed in reduced amounts in many malignancies. However, the prognostic value of miR-219-5p for patients with prostate cancer remains unclear.

METHODS

We retrospectively analysed data from 213 prostate cancer patients from 10 June 2012 to 9 May 2015. Overall survival was assessed by Kaplan-Meier analysis and Cox regression models. Besides, a prediction model was constructed, and calibration curves evaluated the model's accuracy.

RESULTS

Of the 213 patients, a total of 72 (33.8%) died and the median survival time was 60.0 months. We found by multifactorial analysis that miR-219-5p deficiency increased the risk of death by nearly fourfold (HR: 3.86, 95% CI): 2.01 to 7.44, p<0.001) and the risk of progression by twofold (HR: 2.79, 95% CI: 1.68 to 4.64, p<0.001). To quantify each covariate's weight on prognosis, we screened variables by cox model to construct a predictive model. The Nomogram showed excellent accuracy in estimating death's risk, with a corrected C-index of 0.778.

CONCLUSIONS

miR-219-5p can be used as a biomarker to predict death risk in prostate cancer patients. The mortality risk prediction model constructed based on miR-219-5p has good consistency and validity in assessing patient prognosis.

Long non‑coding RNA SChLAP1 regulates the proliferation of triple negative breast cancer cells via the miR‑524‑5p/HMGA2 axis

Long non-coding RNA (lncRNA) second chromosome locus associated with prostate-1 (SChLAP1), also named LINC00913, has been reported to accelerate the carcinogenesis of prostate cancer. The aim of this study was to explore the role and mechanism of SChLAP1 in triple negative breast cancer (TNBC). The expression of SChLAP1 in TNBC tissues and cells was determined by reverse transcription quantitative PCR. The effects of SChLAP1 on the growth of TNBC cells was evaluated by detecting cell viability, colony formation and apoptosis. The present study determined that SChLAP1 was upregulated in TNBC tissues and was associated with the long-distant lymph node metastasis of patients with TNBC. Knockdown of SChLAP1 significantly inhibited cell viability and colony formation, and triggered apoptosis of TNBC cells. Bioinformatics analysis suggested that SChLAP1 acted as a sponge of microRNA (miR)-524-5p and negatively modulated the expression of miR-524-5p. An inverse correlation was also identified between the expression levels of SChLAP1 and miR-524-5p in TNBC tissues. Furthermore, the results demonstrated that SChLAP1 interacted with miR-524-5p, and subsequently regulated the expression level of High Mobility Group AT-Hook 2 (HMGA2) in TNBC cells. It was also found that the overexpression of HMGA2 rescued the suppressed viability of TNBC cells induced by SChLAP1 knockdown. In conclusion, the present findings demonstrated that SChLAP1 modulated the malignant tumor behaviors of TNBC cells by regulating HMGA2 and subsequently restraining miR-524-5p.

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.

miR-760 mediated the proliferation and metastasis of hepatocellular carcinoma cells by regulating HMGA2

BACKGROUND

The purpose of our study was to investigate the roles of miR-760 and its potential mechanisms in HCC.

METHODS

The functions of miR-760 were identified and measured by MTT, colony formation, transwell, and flow cytometry assays. Luciferase assay was applied to verify the direct binding of miR-760 on HMGA2 3'untranslated region (3'UTR). Then, in vitro experiment was used to investigate the biological effects of miR-760 and HMGA2. Luciferase and ChIP assays were used to detect the validity of SP1 binding sites on the miR-760 promoter.

RESULTS

We demonstrated that miR-760 overexpression suppressed cell proliferation, migration, and invasion in HCC. Besides, HMGA2 was demonstrated as a direct target gene of miR-760. Furthermore, we found that methylation may result in the downregulation of miR-760, and SP1 could inhibit the transcription of miR-760.

CONCLUSIONS

Our study demonstrated that SP1/miR-760/HMGA2 may serve as a molecular regulatory axis for HCC treatment.

miR‑454‑3p inhibits non‑small cell lung cancer cell proliferation and metastasis by targeting TGFB2

Accumulating studies have suggested that microRNAs (miRs) play a significant role in lung cancer development and progression, especially in non-small cell lung cancer (NSCLC). The present study aimed to investigate the associations between miR-454-3p and NSCLC progression. qPCR assay was applied to examine the expression of miR-454-3p and transforming growth factor-β2 (TGFB2) in tissues and cell lines. CCK-8 and EdU assays were used to detect cell proliferation. Wound-healing and Transwell assays were conducted to assess cell migration and invasion. Western blotting assay was performed to explore the protein levels of epithelial-mesenchymal transition (EMT) markers. The interaction between miR-454-3p and TGFB2 was investigated with a luciferase reporter assay. miR-454-3p was downregulated in NSCLC tissues and NSCLC cell lines. miR-454-3p overexpression led to the suppression of proliferation, migration, and invasion in A549 and NCI-H1650 cells. In addition, the overexpression of miR-454-3p in A549 and NCI-H1650 cells significantly inhibited EMT. TGFB2 was revealed to be a direct target of miR-454-3p by using TargetScan database and luciferase reporter assay. TGFB2 was observed to be upregulated in NSCLC tissues and cell lines. Further mechanistic studies revealed that the inhibitory effects of miR-454-3p on NSCLC were reversed upon overexpression of TGFB2. These findings provided strong evidence that miR-454-3p suppressed NSCLC cell proliferation and metastasis by targeting TGFB2. The study suggests that targeting miR-454-3p could be a promising strategy for treating NSCLC.

LINC00461 Promoted Endometrial Carcinoma Growth and Migration by Targeting MicroRNA-219-5p/Cyclooxygenase-2 Signaling Axis

Endometrial carcinoma (EC) ranks as the most common female genital cancer in developed countries. Lately, more and more long noncoding RNAs (lncRNAs) have been identified as vital regulators in numerous physiological and pathological processes, including EC. However, the expression pattern and precise functions of different lncRNAs in EC remain unclear. In this study, we reported LINC00461 was upregulated in EC patient tissues and cell lines. In addition, LINC00461 knockdown could remarkably suppress cell proliferation, cell cycle progression, cell migration, and promote cell apoptosis in EC cells. We discovered LINC00461 could sponge microRNA-219-5p (miR-219-5p) and suppress its expression, thereby upregulating expression level of miR-219-5p’s target, cyclooxygenase-2 (COX-2). In vivo animal models, LINC00461 knockdown inhibited tumor growth by increasing miR-219-5p level and reducing COX-2 expression, thus confirming LINC00461 functions as an oncogene in EC. In this study, a novel regulatory role of LINC00461/miR-219-5p/COX-2 axis was systematically investigated in context of EC, with the aim to provide promising intervention targets for EC therapy from bench to clinic.

Elevated high mobility group A2 expression in liver cancer predicts poor patient survival

BACKGROUND

liver cancer is a malignant tumor with a high morbidity and mortality that endangers human health. High mobility group A2 (HMGA2) is a chromosome associated protein that participates in embryogenesis, tissue development, tumorigenesis and development.

OBJECTIVE

to explore the relationship between HMGA2 expression and the clinicopathological parameters and survival of liver cancer patients using The Cancer Genome Atlas Liver Hepatocellular Carcinoma (HCC) data.

METHODS

RNA-sequencing data and the corresponding clinical characteristics of the patients were downloaded from the Atlas database. The Chi-squared test was used to assess the relationship between HMGA2 expression and clinical variables. Cox regression analysis was used to compare survival rates between the high- and low-expressing groups; the p-values and Kaplan-Meier survival curves were compared using the log-rank test.

RESULTS

RNA-seq data from 373 cases of liver cancer cases were analyzed. HMGA2 was overexpressed in liver cancer and significantly associated with gender (p = 0.0357), T classification (p = 0.0063), clinical classification (p = 0.0026) and overall survival (p = 0.0386). According to the multivariate analysis, HMGA2 could independently predict overall survival in liver cancer.

CONCLUSIONS

HMGA2 independently predicts poor prognosis in liver cancer and serves as a molecular marker to determine disease prognosis.

Gynecologic cancers and non-coding RNAs: Epigenetic regulators with emerging roles

Gynecologic cancers involve the female genital organs, such as the vulva, vagina, cervix, endometrium, ovaries, and fallopian tubes. The occurrence and frequency of gynecologic cancer depends on personal lifestyle, history of exposure to viruses or carcinogens, genetics, body shape, and geographical habitat. For a long time, research into the molecular biology of cancer was broadly restricted to protein-coding genes. Recently it has been realized that non-coding RNAs (ncRNA), including long noncoding RNAs (LncRNAs), microRNAs, circular RNAs and piRNAs (PIWI-interacting RNAs), can all play a role in the regulation of cellular function within gynecological cancer. It is now known that ncRNAs are able to play dual roles, i.e. can exert both oncogenic or tumor suppressive functions in gynecological cancer. Moreover, several clinical trials are underway looking at the biomarker and therapeutic roles of ncRNAs. These efforts may provide a new horizon for the diagnosis and treatment of gynecological cancer. Herein, we summarize some of the ncRNAs that have been shown to be important in gynecological cancers.

Long Non-coding RNA Colon Cancer-Associated Transcript-1 Promotes Migration, Invasion, and Epithelial Mesenchymal Transition of Lung Adenocarcinoma by Suppressing miR-219-1

Previous evidence suggests that long non-coding colon cancer-associated transcript-1(CCAT1) plays a pivotal role in the progression of a variety of tumors. However, little is known about its role in lung adenocarcinoma (LAD). In this study, we found LAD tissue samples had a higher expression of CCAT1 but a lower expression of miR-219-1 compared to their adjacent non-tumor tissues. CCAT1 negatively regulated the expression of miR-219-1. miR-219-1 suppressed the proliferation of A549 and H1299 cells. Knockdown of CCAT1 inhibited the proliferation, migration, and invasion of A549 and H1299 cells, which were reversed by the miR-219-1 inhibitor. CCAT1 knockdown increased the expression of E-cadherin but decreased the expressions of N-cadherin and vimentin, which were restored by the miR-219-1 inhibitor. In vivo, knockdown of CCAT1 suppressed the tumor growth of LAD xenografts, which were rescued by the inhibition of miR-219-1. In summary, our findings suggested that CCAT1 promotes the progression of LAD via sponging miR-219-1, providing a potential therapeutic target for LAD.

microRNA-219-5p targets NEK6 to inhibit hepatocellular carcinoma progression

MicroRNA-219-5p (miR-219-5p) is a key post-transcriptional regulator of gene expression that is known to regulate cancer progression, but its role in the context of hepatocellular carcinoma (HCC) remains to be fully elucidated. Herein, it was found that this miRNA functions as a tumor suppressor. Specifically, significant decreases in miR-219-5p expression were detected in HCC cells and patient serum samples relative to that found in the serum of 15 healthy people, and it was concluded that miR-219-5p overexpression was sufficient to impair HCC cell proliferation in vitro and vivo and migration in vitro. At the mechanistic level, it was found that miR-219-5p was able to suppress the expression of NEK6 (never in mitosis gene a-related kinase 6), thereby resulting in dysregulated β-catenin/c-Myc-regulated gene expression. When NEK6 was overexpressed in HCC cells, this was sufficient to reverse the inhibitory impact of miR-219-5p on HCC cell proliferation both in vitro and vivo and metastasis in vitro. Bioinformatics analyses were also conducted, and both miR-219-5p and Nek6 were linked to disease progression in HCC patients with advanced disease. More importantly, the serum specimen data showed that reduced perioperative plasma miR-219-5p correlated significantly with increased risk of early recurrence after curative hepatectomy, whereas it was opposed to NEK6. Together, these findings highlight miR-219-5p as a potentially valuable diagnostic biomarker that can potentially be leveraged to improve clinical outcomes in HCC patients.

The Role of microRNAs in Epithelial Ovarian Cancer Metastasis

Epithelial ovarian cancer (EOC) is the deadliest gynecological cancer, and the major cause of death is mainly attributed to metastasis. MicroRNAs (miRNAs) are a group of small non-coding RNAs that exert important regulatory functions in many biological processes through their effects on regulating gene expression. In most cases, miRNAs interact with the 3′ UTRs of target mRNAs to induce their degradation and suppress their translation. Aberrant expression of miRNAs has been detected in EOC tumors and/or the biological fluids of EOC patients. Such dysregulation occurs as the result of alterations in DNA copy numbers, epigenetic regulation, and miRNA biogenesis. Many studies have demonstrated that miRNAs can promote or suppress events related to EOC metastasis, such as cell migration, invasion, epithelial-to-mesenchymal transition, and interaction with the tumor microenvironment. In this review, we provide a brief overview of miRNA biogenesis and highlight some key events and regulations related to EOC metastasis. We summarize current knowledge on how miRNAs are dysregulated, focusing on those that have been reported to regulate metastasis. Furthermore, we discuss the role of miRNAs in promoting and inhibiting EOC metastasis. Finally, we point out some limitations of current findings and suggest future research directions in the field.

High Mobility Group A (HMGA): Chromatin Nodes Controlled by a Knotty miRNA Network

High mobility group A (HMGA) proteins are oncofoetal chromatin architectural factors that are widely involved in regulating gene expression. These proteins are unique, because they are highly expressed in embryonic and cancer cells, where they play a relevant role in cell proliferation, stemness, and the acquisition of aggressive tumour traits, i.e., motility, invasiveness, and metastatic properties. The HMGA protein expression levels and activities are controlled by a connected set of events at the transcriptional, post-transcriptional, and post-translational levels. In fact, microRNA (miRNA)-mediated RNA stability is the most-studied mechanism of HMGA protein expression modulation. In this review, we contribute to a comprehensive overview of HMGA-targeting miRNAs; we provide detailed information regarding HMGA gene structural organization and a comprehensive evaluation and description of HMGA-targeting miRNAs, while focusing on those that are widely involved in HMGA regulation; and, we aim to offer insights into HMGA-miRNA mutual cross-talk from a functional and cancer-related perspective, highlighting possible clinical implications.

Inhibition of Dimethylarginine Dimethylaminohydrolase (DDAH) Enzymes as an Emerging Therapeutic Strategy to Target Angiogenesis and Vasculogenic Mimicry in Cancer

The small free radical gas nitric oxide (NO) plays a key role in various physiological and pathological processes through enhancement of endothelial cell survival and proliferation. In particular, NO has emerged as a molecule of interest in carcinogenesis and tumor progression due to its crucial role in various cancer-related events including cell invasion, metastasis, and angiogenesis. The dimethylarginine dimethylaminohydrolase (DDAH) family of enzymes metabolize the endogenous nitric oxide synthase (NOS) inhibitors, asymmetric dimethylarginine (ADMA) and monomethyl arginine (L-NMMA), and are thus key for maintaining homeostatic control of NO. Dysregulation of the DDAH/ADMA/NO pathway resulting in increased local NO availability often promotes tumor growth, angiogenesis, and vasculogenic mimicry. Recent literature has demonstrated increased DDAH expression in tumors of different origins and has also suggested a potential ADMA-independent role for DDAH enzymes in addition to their well-studied ADMA-mediated influence on NO. Inhibition of DDAH expression and/or activity in cell culture models and in vivo studies has indicated the potential therapeutic benefit of this pathway through inhibition of both angiogenesis and vasculogenic mimicry, and strategies for manipulating DDAH function in cancer are currently being actively pursued by several research groups. This review will thus provide a timely discussion on the expression, regulation, and function of DDAH enzymes in regard to angiogenesis and vasculogenic mimicry, and will offer insight into the therapeutic potential of DDAH inhibition in cancer based on preclinical studies.