miR-208-3p promotes hepatocellular carcinoma cell proliferation and invasion through regulating ARID2 expression

CVD phenotyping in oncologic disorders: cardio-miRNAs as a potential target to improve individual outcomes in revers cardio-oncology

With the increase of aging population and prevalence of obesity, the incidence of cardiovascular disease (CVD) and cancer has also presented an increasing tendency. These two different diseases, which share some common risk factors. Relevant studies in the field of reversing Cardio-Oncology have shown that the phenotype of CVD has a significant adverse effect on tumor prognosis, which is mainly manifested by a positive correlation between CVD and malignant progression of concomitant tumors. This distal crosstalk and the link between different diseases makes us aware of the importance of diagnosis, prediction, management and personalized treatment of systemic diseases. The circulatory system bridges the interaction between CVD and cancer, which suggests that we need to fully consider the systemic and holistic characteristics of these two diseases in the process of clinical treatment. The circulating exosome-miRNAs has been intrinsically associated with CVD -related regulation, which has become one of the focuses on clinical and basic research (as biomarker). The changes in the expression profiles of cardiovascular disease-associated miRNAs (Cardio-miRNAs) may adversely affect concomitant tumors. In this article, we sorted and screened CVD and tumor-related miRNA data based on literature, then summarized their commonalities and characteristics (several important pathways), and further discussed the conclusions of Cardio-Oncology related experimental studies. We take a holistic approach to considering CVD as a risk factor for tumor malignancy, which provides an in-depth analysis of the various regulatory mechanisms or pathways involved in the dual attribute miRNAs (Cardio-/Onco-miRNAs). These mechanisms will be key to revealing the systemic effects of CVD on tumors and highlight the holistic nature of different diseases. Therefore, the Cardio-miRNAs should be given great attention from researchers in the field of CVD and tumors, which might become new targets for tumor treatment. Meanwhile, based on the principles of precision medicine (such as the predictive preventive personalized medicine, 3PM) and reverse Cardio-oncology to better improve individual outcomes, we should consider developing personalized medicine and systemic therapy for cancer from the perspective of protecting cardiovascular function.

Upregulation LncRNA MEG3 expression suppresses proliferation and metastasis in melanoma via miR-208/SOX4

Long non-coding RNAs (lncRNAs) regulate gene expression and play a significant role in cancer progression. Previously, downregulation of lncRNA MEG3 was shown to associate with poor clinical outcomes in melanoma patients. The basis for this association has not been described and the aims of this study were to identify a role for lncRNA MEG3 in melanoma and to describe its regulatory mechanism of action. RT-qPCR was used to detect lncRNA MEG3 expression in melanoma cells and tissues. Luciferase reporter assays were used to identify lncRNA MEG3 downstream targets. Melanoma cells were transfected with various expression vectors and these transfected cells were assessed for; migration, colony formation, proliferation, in vivo tumorigenesis, and metastatic potential. Melanoma cell lines were found to be sensitive to lncRNA MEG3 expression levels and overexpression was found to inhibit melanoma cell proliferation and invasion, both in vitro and in vivo. Luciferase reporter assays identified miR-208 and SOX4 as downstream targets of lncRNA MEG3. Overexpression of miR-208 and silencing of SOX4 rescued invasion and proliferation by cells that overexpressed lncRNA MEG3. Moreover, lncRNA MEG3 inhibited cancer stem cell differentiation and suppressed melanoma progression and metastasis through inhibition of miR-208 by SOX4.

Expression Signature of the AT-Rich Interactive Domain Gene Family Identified in Digestive Cancer

Background

The AT-rich interactive domain (ARID) gene family of 15 proteins has an important role in development and proliferation. Gene expression alterations of the ARID family are correlated with the pathogenesis of digestive cancer, but systematic research has not been conducted.

Methods

We obtained transcriptome sequencing data, clinical characteristics and stemness indices of the seven main types of digestive cancer (cholangiocarcinoma, colon adenocarcinoma, oesophageal carcinoma, liver hepatocellular carcinoma, pancreatic adenocarcinoma, rectum adenocarcinoma and stomach adenocarcinoma) from public pan-cancer data to combine the analysis of the expression and prognostic signature of the ARID gene family. The stromal and immune scores for each sample were calculated to explore the correlations between the ARID gene family members and the tumour microenvironment.

Results

After screening, 1,920 digestive cancer samples were included in our study. ARID3C was expressed at low levels throughout the digestive cancer samples. The expression levels of ARID1A and JARID1C were relatively high, but there was striking heterogeneity across the different cancer types for specific family members. The survival analysis indicated that many genes were significantly related to the prognosis of patients with liver hepatocellular carcinoma. The stemness indices, stromal score, and immune score analysis showed that the expression of a single ARID gene had characteristic consistency in each tumour, but the levels among the different genes still varied.

Conclusion

Our systematic study of the ARID gene family and its association with the immune infiltrate, tumour microenvironment and outcomes of digestive cancer patients focus on the complex relations and indicate the need to study each ARID member as an individual in a specific cancer type.

Emerging roles of microRNA-208a in cardiology and reverse cardio-oncology

Cardiovascular diseases (CVDs) and cancer, which are the leading causes of mortality globally, have been viewed as two distinct diseases. However, the fact that cancer and CVDs may coincide has been noted by cardiologists when taking care of patients with CVDs caused by cancer chemotherapy; this entity is designated cardio-oncology. More recently, patients with CVDs have also been found to have increased risk of cancers, termed reverse cardio-oncology. Although reverse cardio-oncology has been highlighted as an important disease state in recent studies, how the diseased heart affects cancer and the potential mediators of the crosstalk between CVDs and cancer are largely unknown. Here, we focus on the roles of cardiac-specific microRNA-208a (miR-208a) in cardiac and cancer biology and explore its essential roles in reverse cardio-oncology. Accumulating evidence has shown that within the heart, increased miR-208a promotes myocardial injury, arrhythmia, cardiac remodeling, and dysfunction and that secreted miR-208a in the circulation may have novel roles in promoting tumor proliferation and invasion. This review, therefore, provides insights into the novel roles of miR-208a in reverse cardio-oncology and strategies to prevent secondary carcinogenesis in patients with early- or late-stage heart failure.

CREB1 acts via the miR‑922/ARID2 axis to enhance malignant behavior of liver cancer cells

There is little information on the role of microRNA (miR)‑922 in the malignant behavior of liver cancer. The present study investigated the regulation of miR‑922 expression levels by cAMP response element binding protein 1 (CREB1) in liver cancer tissue, its role in regulating malignant behavior and its potential targets in liver cancer. miR‑922 expression in liver cancer cells and tissue was determined by reverse transcription‑quantitative PCR. The binding of CREB1 to the promoter region of mir‑922 was tested by chromatin immunoprecipitation‑PCR. The predicted AT‑rich interactive domain 2 (ARID2) and fidgetin, microtubule severing factor targets of miR‑922 were characterized by dual luciferase reporter assay. The effects of altered ARID2 expression levels on miR‑922‑enhanced malignant behavior of liver cancer cells were tested. CREB1 bound to the promoter region of miR‑922. Elevated miR‑922 transcripts were inversely associated with ARID2 expression in liver cancer tissue and cells. miR‑922 inhibited ARID2‑regulated luciferase expression and was present in the miR/argonaute RISC catalytic component 2 complex. ARID2 significantly decreased malignant behavior of liver cancer MHCC97L cells. Similarly, ARID2 over‑expression inhibited growth of xenograft liver cancer tumors and decreased miR‑922, Bcl‑2, proliferating cell nuclear antigen, cyclin D1, MMP3 and MMP9 expression and serum VEGF and TNF‑α levels, but enhanced Bax expression levels in tumors. ARID2 over‑expression abrogated malignant behavior promoted by miR‑922 over‑expression and enhanced miR‑922‑decreased malignant behavior of liver cancer cells. CREB induced miR‑922 transcription, which targeted ARID2 to enhance malignant behavior of liver cancer cells, indicating that the CREB1/miR‑922/ARID2 axis may be a potential target for liver cancer treatment.

ARID2 Chromatin Remodeler in Hepatocellular Carcinoma

Chromatin remodelers are found highly mutated in cancer including hepatocellular carcinoma. These mutations frequently occur in ARID (AT-rich Interactive Domain) genes, encoding subunits of the ATP-dependent SWI/SNF remodelers. The increasingly prevalent complexity that surrounds the functions and specificities of the highly modular BAF (BG1/BRM-associated factors) and PBAF (polybromo-associated BAF) complexes, including ARID1A/B or ARID2, is baffling. The involvement of the SWI/SNF complexes in diverse tissues and processes, and especially in the regulation of gene expression, multiplies the specific outcomes of specific gene alterations. A better understanding of the molecular consequences of specific mutations impairing chromatin remodelers is needed. In this review, we summarize what we know about the tumor-modulating properties of ARID2 in hepatocellular carcinoma.

Deficiency of miR-208a Exacerbates CCl4-Induced Acute Liver Injury in Mice by Activating Cell Death Pathways

Acute liver injury (ALI) is associated with multiple cellular events such as necrosis, apoptosis, oxidative stress and inflammation, which can lead to liver failure. In this study, we demonstrate a new role of microRNA (miR)‐208a in ALI. ALI was induced in wild‐type (WT) and miR‐208a knockout (KO) mice by CCl₄ administration. Increased alanine aminotransferase and decreased hepatic miR‐208a levels were found in WT mice after acute CCl₄ treatment. Histopathological evaluations revealed increased necrosis and decreased inflammation in miR‐208a KO compared with WT mice after CCl₄ treatment. CCl₄ treatment induced a higher alanine aminotransferase elevation and increased numbers of circulating extracellular vesicles (exosomes and microvesicles) in miR‐208a KO compared with WT mice. We found increased CCl₄‐induced nuclear factor kappa B activation and tumor necrosis factor‐α induction and decreased monocyte chemoattractant protein 1 levels in miR‐208a KO compared with WT mice. Terminal deoxynucleotidyl transferase–mediated deoxyuridine triphosphate nick‐end labeling assay indicated aggravated hepatic apoptosis and necrosis in CCl₄‐treated miR‐208a KO compared with WT mice. CCl₄ treatment induced a greater increase in cleaved caspase‐8, p18, and caspase‐3 in miR‐208a KO compared with WT mice. p53 is involved in various cell death pathways, including necrosis and apoptosis. Our in silico analysis revealed p53 as a predicted miR‐208a target, and we found enhanced p53 and cyclophilin D protein expressions in miR‐208a KO mice after CCl₄ treatment. Increased liver injury in miR‐208a KO mice was further associated with increased Bax (B cell lymphoma 2–associated X protein) and p21 expression. Our in vitro results indicated a role of miR‐208a in cell death. We found that CCl₄‐induced cytotoxicity was partially rescued by miR‐208a overexpression in RAW macrophages. Altogether, our results revealed a role of miR‐208a in ALI in mice and suggest a role for miR‐208a in regulating cell death.

MiR-155-5p promotes oral cancer progression by targeting chromatin remodeling gene ARID2

BACKGROUND

Dysregulation of miRNAs is associated with aberrant migration and invasion by suppressing relevant target genes in multiple cancers, including oral squamous cell carcinoma (OSCC). Accumulating evidence suggests that microRNA-155-5p is involved in carcinogenesis and tumor progression. However, the exact function and molecular mechanism of miR-155-5p in OSCC remain unclear. This study aimed to investigate the function of miR-155-5p and the molecular mechanisms underlying the influencing progression of OSCC.

METHODS

The miR-155-5p expression level in the OSCC tissues and oral cancer cell lines were determined by the qRT-PCR. Gain-of-function and knockdown approach were used to examine the effect of miR-155-5p on cell proliferation, migration, invasion, and epithelial-mesenchymal transition (EMT) of OSCC. The luciferase reporter assay was applied to confirm the AT-rich interactive domain 2 (ARID2) as a potential target of miR-155-5p, and the rescue experiment was employed to verify the roles of the miRNA-155-5p-ARID2 axis in OSCC progression. Immunohistochemical staining was used to detect ARID2 expression in another cohort sample tissues from OSCC patients.

RESULTS

MiR-155-5p was significantly upregulated in OSCC tissues and cell lines. The miR-155-5p expression level was positively correlated with tumor size, TNM stage, histological grade and lymph node metastasis of OSCC patients. Functional assays demonstrated that miR-155-5p enhanced OSCC cell proliferation, migration and invasion. Mechanistically, ARID2 was identified as a direct target and functional effector of miR-155-5p in OSCC. Furthermore, ARID2 overexpression could rescue the aberrant biological function by overexpressed miR-155-5p in OSCC cells. Notably, we showed that ARID2 could be used as an independent prognosis factor in OSCC.

CONCLUSIONS

Our results suggest that miR-155-5p facilitates tumor progression of OSCC by targeting ARID2, and miR-155-5p-ARID2 axis may be a potential therapeutic target of OSCC.

Bone marrow-derived mesenchymal stem cell-derived exosomal microRNA-208a promotes osteosarcoma cell proliferation, migration, and invasion

A recent study has discovered that mesenchymal stem cells (MSCs) are recruited into tumors and MSC-derived exosomes in a novel mechanism of cell-to-cell communication in human cancers. Here, in this study, we explore the impact of the microRNA-208a (miR-208a)-enriched exosomes derived from bone marrow-derived mesenchymal stem cells (BMSCs) on osteosarcoma cells. Human osteosarcoma cells MG-63 and Saos-2 were exposed to BMSCs-derived exosomes treated with either miR-208a mimic or inhibitor. The MTT assay, transwell migration assay, and soft agar colony formation assay were used to evaluate the viability, migration, and clonogenicity of osteosarcoma cells. Bioinformatics analysis and dual-luciferase reporter gene assays validated the targeted relationship between miR-208a and PDCD4. Western blot assay was used to detect the expression of PDCD4 and related proteins in the ERK1/2 pathway in osteosarcoma cells. BMSCs communicated with osteosarcoma cells via exosomes. Ectopic expression of miR-208a was shown to increase the viability, migration, and clonogenicity of osteosarcoma cells. Analysis of the exosomal content identified miR-208a as a mediator of the exosomal effects on osteosarcoma cells in part via downregulation of PDCD4 and activating the ERK1/2 pathway. In summary, our study illuminates that BMSC-derived exosomal miR-208a enhances the progression of osteosarcoma.

MicroRNA‑208a directly targets Src kinase signaling inhibitor 1 to facilitate cell proliferation and invasion in non‑small cell lung cancer

The abnormal expression of microRNAs (miRNAs/miRs) has a critical function in the formation and progression of non-small cell lung cancer (NSCLC). Therefore, understanding the association between NSCLC and dysregulated miRNAs may allow for the identification of novel diagnostic and therapeutic biomarkers for patients with this malignancy. Previous studies have validated miR-208a as a cancer-associated miRNA in multiple different types of human cancer, however, its expression pattern and precise function in NSCLC remains yet to be elucidated. Therefore, the aims of the present study were to measure miR-208a expression in NSCLC, investigate its specific functions in NSCLC and determine its exact regulatory mechanisms. Herein, the results demonstrated that miR-208a was significantly upregulated in NSCLC tissues and cell lines compared with that in adjacent non-cancerous tissues and a non-tumorigenic bronchial epithelium BEAS-2B cell line (P<0.05, respectively). The high expression level of miR-208a exhibited an obvious association with Tumor-Node-Metastasis stage and lymph node metastasis. miR-208a silencing decreased the proliferative and invasive capacities of NSCLC cells. Notably, Src kinase signaling inhibitor 1 (SRCIN1) was verified as a potential direct target gene of miR-208a in NSCLC cells. Furthermore, SRCIN1 knockdown was able to rescue the miR-208a-mediated effects on NSCLC cells. In addition to this, silencing miR-208a expression inhibited the extracellular regulated kinase (ERK) signaling pathway in NSCLC. Overall, to the best of our knowledge, the present study is the first to provide evidence that miR-208a exerts oncogenic functions in the carcinogenesis and progression of NSCLC by directly targeting SRCIN1 and regulating the ERK pathway. Therefore, miR-208a may be developed as a potential target for treating patients with NSCLC.

MiR-208a-3p functions as an oncogene in colorectal cancer by targeting PDCD4

Accumulating evidences have shown microRNAs (miRNAs) play important roles in the progression of human cancers including colorectal cancer (CRC). However, the biological function and molecular mechanism of miRNAs in CRC still remains to be further investigated. Using microarray, we found and confirmed that miR-208a-3p was up-regulated in CRC tissues. Its high expression was statistically associated with distant metastasis and TNM stage. Functional assays revealed inhibition of miR-208a-3p suppressed proliferation, invasion and migration, and induced cell apoptosis of CRC cells. Moreover, we identified programmed cell death protein 4 (PDCD4), a well-known tumor suppressor, is a direct target of miR-208a-3p. We also found that overexpression of PDCD4 suppressed cell proliferation, invasion, and migration. Importantly, silencing of PDCD4 efficiently abrogated the promoting effects on CRC cells proliferation, invasion, and migration caused by inhibition of miR-208a-3p. Our findings confirmed the oncogenic role of miR-208a-3p via targeting PDCD4 in CRC, identifying miR-208a-3p as a potential diagnosis and therapeutic biomarker for CRC.

MicroRNA-376c-3p Facilitates Human Hepatocellular Carcinoma Progression via Repressing AT-Rich Interaction Domain 2

Hepatocellular carcinoma (HCC), accounting for approximately 90% of liver cancer, is the most lethal malignant tumors in the world. Large amount of evidence indicate that microRNAs (miRNAs) contribute to the tumorigenesis and progression of HCC. Among them, miR-376c-3p was recently identified as a tumor-related miRNA and is up-regulated in HBV-related HCC. But, the clinical significance of miR-376c-3p and its biological function in HCC progression are still unclear. Here, we confirmed that miR-376c-3p expression level in HCC was markedly higher than that in noncancerous tissues. Up-regulation of miR-376c-3p was detected in four different HCC cell lines. High miR-376c-3p expression correlated with poor prognostic features, such as large tumor size and venous infiltration. Follow-up data indicated that high miR-376c-3p level evidently correlated with poor clinical outcomes of HCC patients. Moreover, knockdown of miR-376c-3p repressed HCC cell growth, migration and invasion in vitro. miR-376c-3p overexpression facilitated these malignant behaviors of Bel-7402 cells. Mechanistically, miR-376c-3p posttranscriptionally repressed ARID2 expression by directly interacting with its 3'-UTR. Furthermore, an obvious negative correlation between miR-376c-3p and ARID2 mRNA expression in HCC tissues was confirmed. Notably, miR-376c-3p knockdown suppressed HCC growth and metastasis in nude mice. Gain-of-function experiments showed that ARID2 inhibited cell growth and mobility of Hep3B cells. Subsequently, ARID2 knockdown rescued miR-376c-3p silencing attenuated Hep3B cell proliferation and mobility. Our results suggest that miR-376c-3p exerts an oncogenic role in HCC progression.

MiR-208b regulates cell cycle and promotes skeletal muscle cell proliferation by targeting CDKN1A

Skeletal muscle is the most abundant tissue in the body. The development of skeletal muscle cell is complex and affected by many factors. A sea of microRNAs (miRNAs) have been identified as critical regulators of myogenesis. MiR-208b, a muscle-specific miRNA, was reported to have a connection with fiber type determination. However, whether miR-208b has effect on proliferation of muscle cell was under ascertained. In our study, cyclin-dependent kinase inhibitor 1A (CDKN1A), which participates in cell cycle regulation, was predicted and then validated as one target gene of miR-208b. We found that overexpression of miR-208b increased the expression of cyclin D1, cyclin E1, and cyclin-dependent kinase 2 at the levels of messenger RNA and protein in cattle primary myoblasts in vivo and in vitro. Flow cytometry showed that forced expression of miR-208b increased the percentage of cells at the S phase and decreased the percentage of cells at the G0/G1 phase. These results indicated that miR-208b participates in the cell cycle regulation of cattle primary myoblast cells. 5-Ethynyl-20-deoxyuridine and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assays showed that overexpression of miR-208b promoted the proliferation of cattle primary myoblasts. Therefore, we conclude that miR-208b participates in the cell cycle and proliferation regulation of cattle primary skeletal muscle cell through the posttranscriptional downregulation of CDKN1A.

miR-208a-3p Suppresses Osteoblast Differentiation and Inhibits Bone Formation by Targeting ACVR1

Emerging evidence indicates that many microRNAs (miRNAs) are indispensable regulators of osteoblast differentiation and bone formation. However, the role of miRNAs in mechanotransduction of osteoblasts remains to be elucidated. This study aimed to identify a mechanosensitive miRNA that regulates Activin A receptor type I (ACVR1)-induced osteogenic differentiation. After 4 weeks of hindlimb unloading (HLU) suspension of 6-month-old male C57BL/6J mice, femurs and tibias were harvested to extract total bone RNAs. Elevated levels of miR-208a-3p correlated with a lower degree of bone formation in whole-bone samples of HLU mice. However, in vitro overexpression of miR-208a-3p inhibited osteoblast differentiation, whereas silencing of miR-208a-3p by antagomiR-208a-3p promoted expression of osteoblast activity, bone formation marker genes, and matrix mineralization under mechanical unloading condition. Bioinformatics analysis and a luciferase assay revealed that ACVR1 is a target gene of miR-208a-3p that negatively regulates osteoblast differentiation under mechanical unloading environment. Further, this study also demonstrates that in vivo pre-treatment with antagomiR-208a-3p led to an increase in bone formation and trabecular microarchitecture and partly rescued the bone loss caused by mechanical unloading. Collectively, these results suggest that in vivo, inhibition of miRNA-208a-3p by antagomiR-208a-3p may be a potential therapeutic strategy for ameliorating bone loss.

microRNA‑96 regulates the proliferation of nucleus pulposus cells by targeting ARID2/AKT signaling

The aberrant proliferation of nucleus pulposus (NP) cells has been reported to be implicated in the pathogenesis of intervertebral disc degeneration (IDD). Previous studies have demonstrated that microRNAs (miRNAs), which are a group of small noncoding RNAs, are critical regulators of cell proliferation in various pathologies. However, the role of miRNA‑96 (miR‑96) in the proliferation of NP cells remains to be determined. In the present study, reverse transcription‑quantitative polymerase chain reaction was used to investigate the expression of miR‑96 in NP tissues from patients with IDD and healthy tissues from patients with traumatic lumbar fracture as the control. A dual‑luciferase reporter assay was used to investigate whether AT‑rich interaction domain 2 (ARID2) may be a direct target gene for miR‑96. Furthermore, isolated NP cells from patients with IDD were transfected with miR‑96 mimics and ARID2‑targeting small interfering RNAs; cell proliferation, and the protein expression of Akt, phosphorylated Akt and ARID2 were examined, whereas the effects of an Akt inhibitor on NP cell proliferation were also evaluated. The present results demonstrated that miR‑96 expression was significantly upregulated in IDD samples, and the level of miR‑96 expression was positively associated with disc degeneration grade, which was evaluated by a modified Pfirrmann grading system. In addition, the current study identified ARID2 as a direct gene target of miR‑96. Furthermore, it was demonstrated that ARID2 mRNA expression was inversely correlated with the expression of miR‑96 in NP tissues. In addition, miR‑96 overexpression promoted NP cell proliferation and induced Akt phosphorylation, which led to increased cyclin D1 translation. Notably, overexpression of ARID2 or treatment with an Akt inhibitor decreased the effect of miR‑96 on NP cell proliferation. In conclusion, the results of the present study indicate that miR‑96 may promote the proliferation of human degenerated NP cells by targeting ARID2 via activation of the Akt pathway, and potentially serves as a therapeutic target for IDD.

HBx protein-mediated ATOH1 downregulation suppresses ARID2 expression and promotes hepatocellular carcinoma

Hepatitis B virus X protein plays a crucial role in the pathogenesis of hepatocellular carcinoma. We previously showed that the tumor suppressor ARID2 inhibits hepatoma cell cycle progression and tumor growth. Here, we evaluated whether hepatitis B virus X protein was involved in the modulation of ARID2 expression and hepatocarcinogenesis associated with hepatitis B virus infection. ARID2 expression was downregulated in HBV‐replicative hepatoma cells, HBV transgenic mice, and HBV‐related clinical HCC tissues. The expression levels of HBx were negatively associated with those of ARID2 in hepatocellular carcinoma tissues. Furthermore, HBx suppressed ARID2 at transcriptional level. Mechanistically, the promoter region of ARID2 gene inhibited by HBx was located at nt‐1040/nt‐601 and contained potential ATOH1 binding elements. In addition, ectopic expression of ATOH1 or mutation of ATOH1 binding sites within ARID2 promoter partially abolished HBx‐triggered ARID2 transcriptional repression. Functionally, ARID2 abrogated HBx‐enhanced migration and proliferation of hepatoma cells, whereas depletion of ATOH1 enhanced tumorigenecity of HCC cells. Therefore, our findings suggested that deregulation of ARID2 by HBx through ATOH1 may be involved in HBV‐related hepatocellular carcinoma development.

MicroRNA-500a promotes migration and invasion in hepatocellular carcinoma by activating the Wnt/β-catenin signaling pathway

Increased expression of microRNA-500a (miR-500a) has been reported in the serum of hepatocellular carcinoma (HCC) patients. However, the biological effects and mechanisms of miR-500a in hepatoma cells remain unclear. In this study, we found that miR-500a expression was up-regulated in HCC cell lines and tissues, and that high levels of miR-500a was associated with poor prognosis. We found that miR-500a upregulation promoted migration and invasion in two hepatoma cell lines, HCCLM3 and SMMC7721, while miR-500a downregulation had the opposite effect. We demonstrated that miR-500a activates the Wnt/β-catenin signaling pathway by directly binding to the 3'-untranslated region (UTR) of SFRP2 and GSK-3β mRNA. In conclusion, our results indicate miR-500a promotes HCC migration and invasion through activating Wnt/β-catenin signaling by directly binding to SFPR2 and GSK-3β.

miR-208a-3p suppresses cell apoptosis by targeting PDCD4 in gastric cancer

Programmed cell death 4 (PDCD4) is a novel tumor suppressor gene and a promising target for anticancer therapies. PDCD4 is frequently downregulated in various human cancers; however, the molecular mechanism accounting for the loss expression of PDCD4 in cancers is not fully understood. In this study, we identified specific targeting sites for miR-208a-3p in the 3'-untranslated region (3'-UTR) of the PDCD4 gene which regulated PDCD4 expression. We demonstrated that miR-208a-3p suppressed apoptosis in gastric cancer cells by targeting PDCD4. We also showed that miR-208a-3p promoted the development of tumor growth in xenograft mice by negatively regulating PDCD4. Taken together, this study revealed a critical role for miR-208a-3p as an oncogenic miRNA in gastric carcinogenesis and it may provide a potential novel target for gastric cancer diagnosis and therapy.

MicroRNA networks in pulmonary arterial hypertension: share mechanisms with cancer?

PURPOSE OF REVIEW

Pulmonary arterial hypertension (PAH) is a rare disease with poor prognosis and no therapeutics. PAH is characterized by severe remodeling of precapillary pulmonary arteries, leading to increased vascular resistance, pulmonary hypertension compensatory right ventricular hypertrophy, then heart failure and death. PAH pathogenesis shares similarities with carcinogenesis such as excessive cell proliferation, apoptosis resistance, metabolic shifts, or phenotypic transition. Although PAH is not a cancer, comparison of analogous mechanisms between PAH and cancer led to the concept of a cancer-like disease to emerge. MicroRNAs (miRNAs) are small noncoding RNAs involved in the regulation of posttranscriptional gene expression. miRNA dysregulations have been reported as promoter of the development of various diseases including cancers.

RECENT FINDINGS

Recent studies revealed that miRNA dysregulations also occur in PAH pathogenesis. In PAH, different miRNAs have been implicated to be the main features of PAH pathophysiology (in pulmonary inflammation, vascular remodeling, angiogenesis, and right heart hypertrophy).

SUMMARY

The review summarizes the implication of miRNA dysregulation in PAH development and discusses the similarities and differences with those observed in cancers.

MicroRNAs-208b-3p, 204-5p, 129-2-3p and 3065-5p as predictive markers of oral leukoplakia that progress to cancer

Leukoplakia is the most common precursor lesion of oral squamous cell carcinoma (OSCC). Currently, the risk of progression to OSCC is assessed based on histopathologic examination alone. However, this method fails to identify the subset of microscopically innocuous leukoplakia that ultimately transforms to OSCC. The aim of this study was to determine if microRNAs (miRNAs) can be utilized to identify non- and low-grade dysplastic oral lesions at risk for cancer progression. A retrospective study of genome-wide miRNA expression level analyses was performed in the training cohort (n=20) using deep sequencing formalin-fixed paraffin embedded incisional biopsy tissues from patients with oral leukoplakic lesions diagnosed with non- or low-grade dysplasia and known clinical outcome. The promising miRNA candidates were then evaluated in the validation cohort (n=80) using quantitative real-time PCR (qRT-PCR). Four promising miRNAs-208b-3p, 204-5p, 129-2-3p and 3065-5p were identified. Combining these four miRNAs as a panel with age and histologic diagnosis (p<0.004), our final model had a predictive value for the area under the receiver operating characteristic (ROC) curve (AUC) of 0.792, sensitivity of 76.9% and specificity of 73.7% to accurately identify non- and low-grade dysplastic lesions at risk of cancer progression, which is a significant improvement over histopathologic examination alone (AUC of 0.645). While further investigation is needed, discovery of predictive markers that can accurately identify histologically innocuous oral lesions at high risk for progression to OSSC will significantly improve clinical outcome by means of early intervention.

Restoration of miR-20a expression suppresses cell proliferation, migration, and invasion in HepG2 cells

Objective

To study microRNA (miR)-20a expression in hepatocellular carcinoma (HCC) and its effects on the proliferation, migration, and invasion of HepG2.

Methods

The real-time polymerase chain reaction was used to detect the expression of miR-20a in HCC tissue and normal tissue, as well as in HCC cell lines and normal liver cells. miR-20a mimic and miR negative control (NC) were transfected into HepG2 cells. MTT (3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide) assay was used to detect cell proliferation. Annexin fluorescein isothiocyanate/propidium iodide assay was run to examine the early apoptosis of cells. Transwell chamber assay was carried out to investigate the cell invasion and migration abilities.

Results

miR-20a was lowly expressed both in HCC tissues and HCC cell lines. After transfection of exogenous miR-20 mimics, miR-20a expression in HepG2 cells was significantly increased by 61.29% compared to the blank group (P<0.01). MTT assay showed that the growth of HepG2 cells in the miR-20a mimics group was significantly inhibited, and optical density values during the 36–96 hour time period were dramatically decreased compared to the blank group (P<0.01). Apoptosis rates of the miR-20a mimics group were higher than those of the blank and NC groups (both P<0.01). The number of HCC cells after transfection by miR-20a mimics in the G1 and S phases were 15.88% and 7.89%, respectively, which were lower than in the blank and NC groups (both P<0.05). Transwell assay showed that in the miR-20a mimics group the number of cell migration and invasion were 0.459 and 0.501 times that of the blank group (both P<0.01), and the migration and inhibition rates were 54.1% and 51.4%, respectively. After closing target gene CCND1 in HepG2 cells, the number of cell migration and invasion in the small interfering (si)-CCND1 group were 0.444 and 0.435 times that of the si-NC group (P<0.05); and compared to the si-NC group, the migration and inhibition rates were 55.6% and 56.5%, respectively.

Conclusion

miR-20a can inhibit the growth, invasion, and migration of HepG2 cells, and is therefore promising as a new molecular target for diagnosis and therapy of HCC.

MicroRNA-155 promotes tumor growth of human hepatocellular carcinoma by targeting ARID2

Aberrant expression of microRNA-155 (miR-155) has been reported in several human cancers and is associated with prognosis of patients. However, the clinical significance of miR‑155 and its underlying mechanisms involved in hepatocarcinogenesis remain to be determined. In this study, we demonstrated that the expression of miR-155 was elevated in both hepatocellular carcinoma (HCC) tissues and cell lines. Clinical association analysis revealed that high expression of miR-155 was correlated with malignant clinicopathological characteristics including large tumor size, high Edmondson-Steiner grading and TNM tumor stage. Furthermore, its high expression conferred a reduced 5-year overall survival and disease-free survival of HCC patients. Gain- and loss-of function studies revealed that miR‑155 promoted cell cycle progression, cell proliferation and inhibited apoptosis. Mechanistically, we identified AT-rich interactive domain 2 (ARID2) as a direct downstream target and functional mediator of miR‑155 in HCC cells. Notably, alterations of ARID2 expression abrogated the effects of miR‑155 on HCC cell proliferation, cell cycle and apoptosis. Moreover, we demonstrated that Akt phosphorylation is essential for the functional roles of miR‑155 through altering Cyclin D1 and p27, which were key components of cell cycle machinery. Finally, we disclosed that the downregulation of miR‑155 suppressed tumor growth of HCC by inhibiting Akt signaling pathway. In conclusion, our results indicate that miR‑155 promotes tumor growth of HCC by targeting ARID2-mediated Akt phosphorylation pathway, and potentially serves as a novel prognostic biomarker and therapeutic target for HCC.