MiR-32 induces cell proliferation, migration, and invasion in hepatocellular carcinoma by targeting PTEN. Tumour Biol. 2015;36:4747-4755. [PMID: 25647261 DOI: 10.1007/s13277-015-3124-9]

Targeting Protein Phosphatases for the Treatment of Chronic Liver Disease

There exists a huge number of patients suffering from chronic liver disease worldwide. As a disease with high incidence and mortality worldwide, strengthening the research on the pathogenesis of chronic liver disease and the development of novel drugs is an important issue related to the health of all human beings. Phosphorylation modification of proteins plays a crucial role in cellular signal transduction, and phosphatases are involved in the development of liver diseases. Therefore, this article summarized the important role of protein phosphatases in chronic liver disease with the aim of facilitating the development of drugs targeting protein phosphatases for the treatment of chronic liver disease.

Overexpression of miR-32 in Chinese hamster ovary cells increases production of Fc-fusion protein

The demand for industrial genetically modified host cells were increased with the growth of the biopharmaceutical market. Numerous studies on improving host cell productivity have shown that altering host cell growth and viability through genetic engineering can increase recombinant protein production. During the last decades, it was demonstrated that overexpression or downregulation of some microRNAs in Chinese Hamster Ovary (CHO) cells as the host cell in biopharmaceutical manufacturing, can improve their productivity. The selection of microRNA targets has been based on their previously identified role in human cancers. MicroRNA-32 (miR-32), which is conserved between humans and hamsters (Crisetulus griseus), was shown to play a role in the regulation of cell proliferation and apoptosis in some human cancers. In this study, we investigated the effect of miR-32 overexpression on the productivity of CHO-VEGF-trap cells. Our results indicated that stable overexpression of miR-32 could dramatically increase the productivity of CHO cells by 1.8-fold. It also significantly increases cell viability, batch culture longevity, and cell growth. To achieve these results, following the construction of a single clone producing an Fc-fusion protein, we transfected cells with a pLexJRed-miR-32 plasmid to stably produce the microRNA and evaluate the impact of mir-32 overexpression on cell productivity, growth and viability in compare with scrambled control. Our findings highlight the application of miRNAs as engineering tools and indicated that miR-32 could be a target for engineering CHO cells to increase cell productivity.

The miRNome of canine invasive urothelial carcinoma

Urothelial carcinoma (UC) comprises up to 2% of all naturally occurring neoplasia in dogs and can be challenging to diagnose. MicroRNAs (miRNAs) have been reported to be dysregulated in numerous diseases, including neoplasia. MiRNA expression has been evaluated in human UC, but there is limited information regarding the miRNA transcriptome of UC in dogs. Our study aimed to evaluate differential miRNA expression in bladder tissue collected from normal canine urothelium and canine invasive UC (iUC) to elucidate the dysregulated pathways in canine UC. Next-Generation RNA sequencing (RNA-Seq) was performed for dogs with UC (n = 29) and normal canine urothelium (n = 4). Raw RNA data were subjected to normalization, and pairwise comparison was performed using EdgeR with Benjamini-Hochberg FDR multiple testing correction (p < 0.05; >2-fold change) comparing tissue samples of normal urothelium to canine iUC samples. Principal component analysis and hierarchical cluster analysis were performed. MiRNA of FFPE tissue samples of separate iUC (n = 5) and normal urothelium (n = 5) were used to evaluate five miRNAs using RT-qPCR. Pathway analysis was performed utilizing miRWalk, STRING database, and Metascape utilizing KEGG pathways and GO terms databases. Twenty-eight miRNAs were differentially expressed (DE) by RNA-Seq. RT-qPCR confirmed that four miRNAs are significantly downregulated in UC compared to healthy urothelial samples (miR-105a, miR-143, miR-181a, and miR-214). Principal component analysis and hierarchical cluster analysis showed separation between miRNAs in iUC and the control group. The DE miRNAs are most often associated with gene silencing by miRNA, miRNAs in cancer, and miRNAs involved in DNA damage responses. Proteins involved include HRAS, KRAS, ARAF, RAF1, MAPK1, MAP2K1, MAPK3, FGFR3, EGFR, HBEGF, RASSF1, E2F2, E2F3, ERBB2, SRC, MMP1, and UP3KA. The differential expression of miRNAs in canine iUC compared to normal canine urothelial tissue indicates that these markers should be further evaluated for their potential role as diagnostic and therapeutic targets.

Hepatocellular Carcinoma: The Role of MicroRNAs

Hepatocellular carcinoma (HCC) is the second leading cause of cancer-related deaths worldwide. HCC is diagnosed in its advanced stage when limited treatment options are available. Substantial morphologic, genetic and epigenetic heterogeneity has been reported in HCC, which poses a challenge for the development of a targeted therapy. In this review, we discuss the role and involvement of several microRNAs (miRs) in the heterogeneity and metastasis of hepatocellular carcinoma with a special emphasis on their possible role as a diagnostic and prognostic tool in the risk prediction, early detection, and treatment of hepatocellular carcinoma.

Functional and Clinical Significance of Dysregulated microRNAs in Liver Cancer

Liver cancer is the leading cause of cancer-related mortality in the world. This mainly reflects the lack of early diagnosis tools and effective treatment methods. MicroRNAs (miRNAs) are a class of non-transcribed RNAs, some of which play important regulatory roles in liver cancer. Here, we discuss microRNAs with key impacts on liver cancer, such as miR-122, miR-21, miR-214, and miR-199. These microRNAs participate in various physiological regulatory pathways of liver cancer cells, and their modulation can have non-negligible effects in the treatment of liver cancer. We discuss whether these microRNAs can be used for better clinical diagnosis and/or drug development. With the advent of novel technologies, fast, inexpensive, and non-invasive RNA-based biomarker research has become a new mainstream approach. However, the clinical application of microRNA-based markers has been limited by the high sequence similarity among them and the potential for off-target problems. Therefore, researchers particularly value microRNAs that are specific to or have special functions in liver cancer. These include miR-122, which is specifically expressed in the liver, and miR-34, which is necessary for the replication of the hepatitis C virus in liver cancer. Clinical treatment drugs have been developed based on miR-34 and miR-122 (MRX34 and Miravirsen, respectively), but their side effects have not yet been overcome. Future research is needed to address these weaknesses and establish a feasible microRNA-based treatment strategy for liver cancer.

Aberrant expression of PI3K/AKT signaling is involved in apoptosis resistance of hepatocellular carcinoma

Phosphatidylinositol 3-kinase (PI3K)/AKT signaling is a crucial pathway for cell survival and proliferation, which are regulated by several growth factors and activated receptors. Upregulated PI3K/AKT signaling molecules were reported in several cancers and they are associated with altered cellular functions, leading to oncogenesis. Here, we have examined the implications of elevated PI3K/AKT expression in the apoptosis resistance of human hepatocellular carcinoma (HCC) Huh7 cells. We showed that PI3K/AKT signaling is significantly upregulated in Huh7 cells by quantitative polymerase chain reaction and protein expression analysis. Also, perversely upregulated PI3K/AKT signaling Huh7 cells are highly resistant to treatment with chemotherapy drugs (docetaxel and sorafenib) and acquired apoptosis resistance through downregulation of tumor suppressor protein PTEN (phosphatase and tensin homolog deleted on chromosome ten). Hence, we have investigated the effect of PTEN overexpression on apoptosis induction in Huh7 cells. We showed that PTEN overexpressed Huh7 cells became more sensitive toward the aforesaid drugs and induced apoptotic cell death due to intracellular reactive oxygen species (ROS) generation. Concurrently, the overexpression of PTEN leads to the activation of mitochondria facilitated intrinsic apoptosis, evidenced by upregulated cytochrome C, caspase 3, and caspase 9. Collectively, our data suggest that the aberrant expression of PI3K/AKT signaling contributes to apoptosis resistance in HCC.

Long non-coding RNA UCA1 enhances cervical cancer cell proliferation and invasion by regulating microRNA-299-3p expression

The long non-coding RNA, urothelial cancer-associated 1 (UCA1) is an important regulator in several tumors. However, to the best of our knowledge, the clinical roles of UCA1 in cervical cancer remain unclear. Thus, the present study aimed to investigate the function and mechanism of UCA1 in cervical cancer. Reverse transcription-quantitative PCR analysis was performed to detect UCA1 and microRNA (miR)-299-3p expression in cervical cancer tissues and cell lines. The Cell Counting Kit-8 and Transwell assays were performed to assess cell proliferation and invasion, respectively. Furthermore, the dual-luciferase reporter assay was performed to confirm the association between UCA1 and miR-299-3p. Rescue experiments were performed to determine the mechanism of the UCA1/miR-299-3p axis. The results demonstrated that UCA1 expression was upregulated in cervical cancer tissues and cell lines. Furthermore, overexpression of UCA1 enhanced the proliferation and invasion of cervical cancer cells, the effects of which were reversed following UCA1 knockdown. Notably, UCA1 interacted with miR-299-3p and negatively regulated miR-299-3p expression. In addition, miR-299-3p expression was downregulated in cervical cancer tissues and cell lines. Overexpression of miR-299-3p suppressed the proliferation and invasion of cervical cancer cells, reversing the effects of UCA1 knockdown on cervical cancer cell proliferation. Taken together, the results of the present study suggest that UCA1 promotes cell proliferation and invasion by regulating miR-299-3p expression in cervical cancer.

Aberrant expression profile of miR-32, miR-98 and miR-374 in chronic lymphocytic leukemia

INTRODUCTION

Leukemia is a malignant and progressive disease of hematopoiesis. The disease arises due to abnormal proliferation and development of white blood cells and their precursors in the blood and bone marrow. Chronic lymphoblastic leukemia (CLL) is a subtype of blood cancers, with the origin of B lymphocytes and the involvement of bone marrow, blood and lymph nodes. MicroRNAs (miRNAs) are small non-coding RNAs with pivotal roles in cellular and molecular processes related to different malignancies, including CLL. In this way, we aimed to evaluate the expression of miR-32-5p, miR-98-5p, and miR-374b-5p in CLL patients. We also investigated the signaling pathways regulated by the studied miRs and also frequently disturbed miRs in CLL.

METHODS

Blood samples were collected from 32 CLL patients from Kermanshah province, Iran and 34 age and sex-matched healthy individuals. RNA was extracted from PBMCs and then was subjected to cDNA synthesis. Using specifically designed primers and Real-Time PCR method the expression of miRNAs was detected and was statistically analyzed. Using mirPath v.3, systematic pathway enrichment analysis was performed for the three studied miRNAs here along with the frequently disturbed miRNAs in CLL.

RESULTS

The experiments indicated a significant reduction in the expression of all three miRs (p-value<0.0001) in CLL patients compared with healthy individuals. ROC analysis suggested that the three studied miRs can serve as potential biomarkers for early diagnosis of CLL. The in silico analysis suggested proteoglycans in cancer as a pathway regulated by the studied miRs and frequently dysregulated miRs in CLL.

CONCLUSION

The observed reduction in expression of miR-32-5p, miR-98-5p, and miR-374b-5p in treatment naïve CLL patients here might be suggestive of their modulatory protective role in CLL progression. Moreover, the candidate peripheral miRNAs could potentially serve as diagnostic biomarkers which warrant further investigation in a larger sample size.

lncRNA MT1JP-overexpression abolishes the silencing of PTEN by miR-32 in hepatocellular carcinoma

Previous studies have shown that long non-coding RNA (lncRNA) MT1JP plays a role as a tumor suppressor in several types of cancer. The present study aimed to explore the role of MT1JP in hepatocellular carcinoma (HCC). Paired HCC and non-tumor tissues from 64 patients with HCC were subjected to RNA isolation and reverse transcription-quantitative PCR (RT-qPCR) to analyze the differential expression of MT1JP, microRNA (miR)-32 and phosphatase and tensin homolog (PTEN) in HCC. Cell transfections, followed by RT-qPCR and western blotting, were carried out to investigate the interactions among MT1JP, miR-32 and PTEN. The role of MT1JP, miR-32 and PTEN in regulating HCC cell proliferation was assessed using a Cell Counting Kit-8 assay. It was found that MT1JP was downregulated in HCC cancer tissues compared with that in non-cancer tissues. Survival analysis showed that patients with low MT1JP expression levels exhibited a significantly higher 5-year overall survival rate compared with patients with high MT1JP levels. The expression of MT1JP in HCC tissues was positively associated with PTEN and negatively associated with miR-32. Overexpression of MT1JP increased the expression levels of PTEN and decreased the expression levels of miR-32. Overexpression of miR-32 did not affect the expression of MT1JP but decreased the expression levels of PTEN and attenuated the effect of overexpression of MT1JP on the expression of PTEN. Overexpression of MT1JP and PTEN decreased the proliferation of HCC cells. Overexpression of miR-32 played an opposite role and attenuated the effects of overexpression of MT1JP. Therefore, MT1JP may upregulate PTEN by downregulating miR-32 to regulate HCC cell proliferation.

ERCC6L promotes the progression of hepatocellular carcinoma through activating PI3K/AKT and NF-κB signaling pathway

Background

Excision Repair Cross-Complementation group 6-like (ERCC6L) has been shown to exhibit carcinogenic effect in several malignant tumors. However, the function and molecular mechanism of the ERCC6L in hepatocellular carcinoma (HCC) have not been investigated extensively.

Methods

Immunohistochemistry analyses were used to detect ERCC6L expression in a HCC tissue microarray, and the Chi-square test was used to assess the correlation between ERCC6L expression and patients’ clinicopathological features. shRNA was used to down-regulation ERCC6L expression in HCC cell lines. MTT assay, plate clone formation assay, flow cytometry, caspase 3/7 activity and migration assays were performed to evaluate the impact of ERCC6L on HCC cells in vitro. Nude mice xenograft models were used to assess the role of ERCC6L in vivo. The regulatory of mechanism of PI3K/AKT pathway was evaluated by western blotting.

Results

ERCC6L was highly expressed in HCC tissue compared with tumor adjacent tissues in 90 paired samples. ERCC6L expression positively correlated with gender, tumor encapsulation, and pathological stage. Patients with low ERCC6L expression had significantly longer OS than those with high ERCC6L expression. Knockdown of ERCC6L expression significantly inhibited proliferation, invasion and metastasis in vitro and tumor growth in vivo, and it promoted cell cycle arrest and apoptosis. Mechanistic analyses revealed that PI3K/AKT and NF-κB signaling pathway were inhibited by silencing ERCC6L.

Conclusion

These results demonstrate that ERCC6L plays a critical role in HCC progression, and thereby might be a potential therapeutic target for HCC patients.

MicroRNA-32 promotes ovarian cancer cell proliferation and motility by targeting SMG1

Ovarian cancer (OC) is the most lethal gynecological malignancy and one of the leading causes of cancer-related deaths among women. Metastasis is the main cause of poor prognosis in OC. MicroRNA (miRNA/miR) has been shown to play an important role in tumorigenesis and metastasis in various cancer types by affecting the expression of its targets. In the present study, the role of miR-32 (miR-32-5p) in OC was explored. Reverse transcription-quantitative PCR results showed that miR-32 expression was significantly upregulated in both OC tissues and cell lines. Inhibition of miR-32 by transfection with miR-32 inhibitor in OC cells markedly suppressed cell proliferation, migration and invasion. In addition, a luciferase assay showed that suppressor of morphogenesis in genitalia 1 (SMG1) is a direct target of miR-32, and interference in SMG1 expression with transfection of SMG1 small hairpin RNA restored miR-32-mediated OC cell proliferation, migration and invasion. Taken together, these results indicate that miR-32 may promote OC cell growth and motility by targeting SMG1. The data of the present study suggest that miR-32 may serve as a potential therapeutic target for OC treatment in the future.

Challenges in Cancer Biomarker Discovery Exemplified by the Identification of Diagnostic MicroRNAs in Prostate Tissues

Identification and clinical translation of routinely tested biomarkers require a complex and multistep workflow. Here, we described a confirmatory process estimating the utility of previously identified candidate tissue miRNAs for diagnosis of prostate cancer (PCa). RNA was isolated from formalin-fixed paraffin-embedded (FFPE) prostate tissue surgically resected from 44 patients with PCa and 24 patients with benign prostate hyperplasia (BPH). Of the 92 RNA samples obtained, 68 represented 42 malignant (PCa) areas and 26 represented nonmalignant (PCa 0%) areas of the prostate tissue sections. The levels of miR-32-5p, miR-183-5p, miR-141-5p, miR-187-3p, miR-375, miR-663b, miR-615-3p, miR-205-5p, miR-221-3p, and miR-222-3p were evaluated using Exiqon chemistry. Five (miR-32-5p, miR-141-5p, miR-187-3p, miR-375, and miR-615-3p), one (miR-32-5p), and two (miR-32-5p and miR-141-5p) miRNAs discriminated between BPH and areas of cancer-bearing prostate tissue harboring different numbers of cancer cells (PCa 15–70%, PCa 2–10%, and PCA 0%, respectively), with an area under the receiver operating characteristics curve (AUC-ROC) > 0.9. Only miRNA 32-5p discriminated BPH specimens from sections of cancer-bearing prostate tissue with a low percentage, a high percentage, or no dysplastic cells. miR-32-5p could be considered as potential diagnostic biomarker discriminating BPH from noncancerous areas within cancer-bearing prostate tissue. However, further clinical studies are warranted to confirm its diagnostic utility.

Micromanaging aerobic respiration and glycolysis in cancer cells

BACKGROUND

Cancer cells possess a common metabolic phenotype, rewiring their metabolic pathways from mitochondrial oxidative phosphorylation to aerobic glycolysis and anabolic circuits, to support the energetic and biosynthetic requirements of continuous proliferation and migration. While, over the past decade, molecular and cellular studies have clearly highlighted the association of oncogenes and tumor suppressors with cancer-associated glycolysis, more recent attention has focused on the role of microRNAs (miRNAs) in mediating this metabolic shift. Accumulating studies have connected aberrant expression of miRNAs with direct and indirect regulation of aerobic glycolysis and associated pathways.

SCOPE OF REVIEW

This review discusses the underlying mechanisms of metabolic reprogramming in cancer cells and provides arguments that the earlier paradigm of cancer glycolysis needs to be updated to a broader concept, which involves interconnecting biological pathways that include miRNA-mediated regulation of metabolism. For these reasons and in light of recent knowledge, we illustrate the relationships between metabolic pathways in cancer cells. We further summarize our current understanding of the interplay between miRNAs and these metabolic pathways. This review aims to highlight important metabolism-associated molecular components in the hunt for selective preventive and therapeutic treatments.

MAJOR CONCLUSIONS

Metabolism in cancer cells is influenced by driver mutations but is also regulated by posttranscriptional gene silencing. Understanding the nuanced regulation of gene expression in these cells and distinguishing rapid cellular responses from chronic adaptive mechanisms provides a basis for rational drug design and novel therapeutic strategies.

High glucose promotes hepatic fibrosis via miR‑32/MTA3‑mediated epithelial‑to‑mesenchymal transition

Hepatic fibrosis is characterized by the aberrant production and deposition of extracellular matrix (ECM) proteins. Growing evidence indicates that the epithelial‑mesenchymal transition serves a crucial role in the progression of liver fibrogenesis. Although a subset of microRNAs (miRNAs or miRs) has recently been identified as essential regulators of the EMT gene expression, studies of the EMT in hyperglycemic‑induced liver fibrosis are limited. In the current study, it was observed that high glucose‑treated AML12 cells occurred EMT process, and miR‑32 expression was markedly increased in the liver tissue of streptozotocin‑induced diabetic rats and in high glucose‑treated AML12 cells. Additionally, the contribution of the EMT to liver fibrosis by targeting metastasis‑associated gene 3 (MTA3) under hyperglycemic conditions was suppressed by AMO‑32. The results indicated that miR‑32 and MTA3 may be considered as novel drug targets in the prevention and treatment of liver fibrosis under hyperglycemic conditions. These finding improves the understanding of the progression of liver fibrogenesis.

microRNAs: Key players in virus-associated hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is known as one of the major health problems worldwide. Pathological analysis indicated that a variety of risk factors including genetical (i.e., alteration of tumor suppressors and oncogenes) and environmental factors (i.e., viruses) are involved in beginning and development of HCC. The understanding of these risk factors could guide scientists and clinicians to design effective therapeutic options in HCC treatment. Various viruses such as hepatitis B virus (HBV) and hepatitis C virus (HCV) via targeting several cellular and molecular pathways involved in HCC pathogenesis. Among various cellular and molecular targets, microRNAs (miRNAs) have appeared as key players in HCC progression. miRNAs are short noncoding RNAs which could play important roles as oncogenes or tumor suppressors in several malignancies such as HCC. Deregulation of many miRNAs (i.e., miR-222, miR-25, miR-92a, miR-1, let-7f, and miR-21) could be associated with different stages of HCC. Besides miRNAs, exosomes are other particles which are involved in HCC pathogenesis via targeting different cargos, such as DNAs, RNAs, miRNAs, and proteins. In this review, we summarize the current knowledge of the role of miRNAs and exosomes as important players in HCC pathogenesis. Moreover, we highlighted HCV- and HBV-related miRNAs which led to HCC progression.

MicroRNA-32 Regulates Development and Progression of Hepatocellular Carcinoma by Targeting ADAMTS9 and Affects Its Prognosis

Background

MicroRNA-32 (miR-32) induces cell proliferation and metastasis in hepatocellular carcinoma (HCC), but the detailed mechanisms of miR-32 in regulating oncogenesis and development of HCC have not been clarified. The aim of this study was to investigate the effects of miR-32 on HCC and its clinical pathological significance, as well as to determine the functional connection between miR-32 and ADAMTS9 in HCC.

Material/Methods

Quantitative RT-PCR was used to assess the expression levels of miR-32 in HCC tissues, adjacent non-cancerous tissues, and liver cancer cell lines. In vitro cell proliferation, migration, and invasion assays were performed to confirm the biological functions of miR-32. Quantitative RT-PCR, Western blot analysis, and luciferase reporter assays were used to evaluate the role of miR-32 in the regulation of ADAMTS9.

Results

miR-32 was highly expressed in HCC tissues compared with corresponding adjacent non-cancerous tissues. Over-expression of miR-32 was also found in 3 human liver cancer cell lines: SMMC-7721, Huh7, and HepG2. Moreover, increasing expression of miR-32 in HCC tissues was related to shorter overall survival. In vitro over-expression of miR-32 promoted cell proliferation, migration, and invasion; however, the under-expression of miR-32 revealed the opposite effects. Dual-luciferase reporter assay indicated that miR-32 can directly bind to the 3′-UTR of ADAMTS9. Western blot analysis showed that over-expression of miR-32 decreased expression of ADAMTS9 protein. Rescue tests further verified the connection between miR-32 and ADAMTS9.

Conclusions

Our data indicate that miR-32 accelerates progression in HCC by targeting ADAMTS9, and the abnormal expression of miR-32 is correlated with prognosis and could become a potential therapeutic target.

miR-32 promotes esophageal squamous cell carcinoma metastasis by targeting CXXC5

MicroRNA-32 (miR-32) functioned as a tumor oncogene in some cancer, which control genes involved in important biological and pathological functions and facilitate the tumor growth and metastasis. However, the role of miR-32 modulates esophageal squamous cell carcinoma (ESCC) malignant transformation has not been clarified. Here, we focused on the function and the underlying molecular mechanism of miR-32 in ESCC. Results discovered a significant increased expression of miR-32 in ESCC tissues and cells. Downregulation of miR-32 inhibited the migration, invasion, adhesion of ESCC cell lines (EC9706 and KYSE450), and the levels of EMT protein in vitro. In vivo, miR-32 inhibitors decrease tumor size, tumor weight, and the number of metastatic nodules. Hematoxylin and eosin (H&E) results revealed that inhibition of miR-32 attenuate lung metastasis. Immunohistochemistry and immunofluorescence assay showed increased level of E-cadherin and decreased level of N-cadherin and Vimentin with treatment of miR-32 inhibitors. Furthermore, miR-32 targeted the 3'-untranslated region (3'-UTR) of CXXC5, and inhibited the level of mRNA and protein of CXXC5. There is a negative correlation between the expressions of CXXC5 and miR-32. Then, after EC9706 and KYSE450 cells cotransfected with si-CXXC5 and miR-32 inhibitors, the ability of cell migration, invasion, and adhesion was significantly reduced. In addition, the protein expression of EMT and TGF-β signaling was also depressed. Collectively, these data supply an insight into the positive role of miR-32 in ESCC progression and metastasis, and its biological effects may attribute the inhibition of TGF-β signaling mediated by CXXC5.

Exosomal microRNA-32-5p induces multidrug resistance in hepatocellular carcinoma via the PI3K/Akt pathway

BACKGROUND

Multidrug resistance is the main obstacle for hepatocellular carcinoma (HCC) treatment. miR-32-5p is involved in HCC progression but its function in multidrug resistance is still unclear. Here we aim to find out the function of miR-32-5p in inducing multidrug resistance and its underlying mechanisms of transforming sensitive cell to resistant cell.

METHODS

We detected the expression of miR-32-5p and PTEN in the multidrug-resistant cell line (Bel/5-FU) and the sensitive cell line (Bel7402), HCC and para-carcinoma liver tissues through real-time PCR. Dual-luciferase reporter assay verified PTEN is the target of miR-32-5p. Exosomes from sensitive and multidrug resistant cell line were obtained and confirmed through ultracentrifuge and Nano Analyzer. Gain- and loss-of-function experiments, rescue experiments, a PI3K/Akt pathway inhibitor, an exosome biogenesis inhibitor, and nude mice xenograft models were used to determine the underlying mechanisms of miR-32-5p and PTEN, as well as exosomal miR-32-5p in inducing multidrug resistance in vitro and in vivo.

RESULTS

miR-32-5p was significantly elevated but PTEN was reduced in Bel/5-FU. An inverse correlation between miR-32-5p and PTEN was confirmed in HCC cell lines and patients; moreover, high expression of miR-32-5p and low expression of PTEN were positively associated with poor prognosis. Over-expression of miR-32-5p activated the PI3K/Akt pathway by suppressing PTEN and induced multidrug resistance via exosomes through promoting angiogenesis and epithelial-mesenchymal transition (EMT).

CONCLUSIONS

Our study demonstrated that the multidrug-resistant cell, Bel/5-FU delivers miR-32-5p to sensitive cell, Bel7402 by exosomes and activates the PI3K/Akt pathway to further induce multidrug resistance by modulating angiogenesis and EMT.

Circulating microRNAs found dysregulated in ex-exposed asbestos workers and pleural mesothelioma patients as potential new biomarkers

Malignant pleural mesothelioma (MPM), a fatal cancer, is an occupational disease mostly affecting workers ex-exposed to asbestos fibers. The asbestos, a cancerogenic mineral of different chemical composition, was widely employed in western Countries in industrial manufactures of different types. MPM may arise after a long latency period, up to five decades. MPM is resistant to conventional chemo- and radio-therapies. Altogether, these data indicate that the identification of new and specific markers are of a paramount importance for an early diagnosis and treatment of MPM. In recent years, microRNAs expression was found dysregulated in patients, both in cancer cells and sera, affected by tumors of different histotypes, including MPM. Cell and circulanting microRNAs, found to be dysregulated in this neoplasia, were proposed as new biomarkers. It has been reported that circulating microRNAs are stable in biological fluids and could be employed as potential MPM biomarkers. In this investigation, circulating microRNAs (miR) from serum samples of MPM patients and workers ex-exposed to asbestos fibers (WEA) and healthy subjects (HS) were comparatively analyzed by microarray and RT-qPCR technologies. Our results allowed (i) to select MiR-3665, an endogenous stable microRNA, as the internal control to quantify in our analyses circulating miRNAs; to detect (ii) miR-197-3p, miR-1281 and miR 32-3p up-regulated in MPM compared to HS; (iii) miR-197-3p and miR-32-3p up-regulated in MPM compared to WEA; (iv) miR-1281 up-regulated in both MPM and WEA compared to HS. In conclusion, three circulating up-regulated microRNAs, i.e. miR-197-3p, miR-1281 and miR-32-3p are proposed as potential new MPM biomarkers.

Upregulation of microRNA-32 is associated with tumorigenesis and poor prognosis in patients with hepatocellular carcinoma

MicroRNA-32 (miR-32) is associated with tumor progression and poor prognosis in certain malignant tumors. However, the function and clinical relevance of miR-32 in human hepatocellular carcinoma (HCC) has not yet been elucidated. The present study aimed to investigate the expression and prognostic value of miR-32 from liver samples in patients with HCC. The expression of miR-32 was analyzed in HCC and healthy tissues using Gene Expression Omnibus datasets. Reverse transcription-quantitative polymerase chain reaction was used to analyze the levels of miR-32 mRNA in 154 HCC liver samples, 33 of which were paired with adjacent non-tumor tissues. The overall survival (OS) rate in patients with HCC was evaluated using Kaplan-Meier survival analysis, and the factors that may affect the prognosis and survival of patients with HCC were analyzed using univariate (log-rank test) and multivariate Cox proportional hazard models. The present results demonstrated that miR-32 expression levels were significantly upregulated in HCC liver biopsies compared with normal tissues (P<0.05). miR-32 expression was significantly associated with the number of foci and tumor diameter (P<0.05). In addition, Kaplan-Meier analysis revealed that patients with low miR-32 expression had longer OS and disease-free survival compared with those with high miR-32 expression (P<0.01). Altogether, to the best our knowledge, the present study is the first study to indicate the association between increased miR-32 expression with HCC progression and poor prognosis in patients. This suggests that miR-32 may have potential prognostic value and may be used as a tumor biomarker for the diagnosis of patients with HCC.

mTOR signaling-related MicroRNAs and Cancer involvement

MicroRNAs (miRNAs) are a class of single-stranded RNAs, 18-23 nucleotides in length that regulate gene expression at the post-transcriptional level. Dysregulation of miRNAs has been closely associated with the development of cancer. In the process of tumorigenesis, mammalian target of rapamycin (mTOR) plays important roles, and the mTOR signaling pathway is aberrant in various types of human cancers, including non-small cell lung cancer (NSCLC), breast cancer, prostate cancer, as well as others. However, the relationship between miRNAs and the mTOR signaling pathway is indistinct. Herein, we not only summarize the progress of miRNAs and the mTOR signaling pathway in cancers, but also highlight their role in the diagnosis and treatment in the clinic.

MicroRNA-630 suppresses tumor metastasis through the TGF-β- miR-630-Slug signaling pathway and correlates inversely with poor prognosis in hepatocellular carcinoma

The epithelial-mesenchymal transition (EMT) is the key process that drives tumor metastasis. Accumulating evidence suggests that the deregulation of some microRNAs (miRNAs), is implicated in this process. Here, we highlight the function and molecular mechanism of miR-630 and its potential clinical application in hepatocellular carcinoma (HCC). First, we identified the clinical relevance of miR-630 expression in a screen of 97 HCC patient tissues. Patients with low miR-630 expression had higher recurrence rates and shorter overall survival than those with high miR-630 expression. Functional studies demonstrated the overexpression of miR-630 in HCC cells attenuated the EMT phenotype in vitro. Conversely, inhibition of miR-630 promoted EMT in HCC cells. Mechanistically, our data revealed that miR-630 suppressed EMT by targeting Slug. Knockdown of Slug expression reversed miR-630 inhibitor-mediated EMT progression. Furthermore, we found that the TGF-β-Erk/SP1 and JNK/c-Jun signaling pathways repressed miR-630 transcription through occupying transcription factor binding sites. Ectopic expression of miR-630 restored the TGF-β-activated EMT process. Taken together, these findings demonstrate, in HCC cells, miR-630 exerts its tumor-suppressor functions through the TGF-β-miR-630-Slug axis and provides a potential prognostic predictor for HCC patients.

miR-148a-3p Mediates Notch Signaling to Promote the Differentiation and M1 Activation of Macrophages

The Notch pathway plays critical roles in the differentiation and polarized activation of macrophages; however, the downstream molecular mechanisms underlying Notch activity in macrophages remain elusive. Our previous study has identified a group of microRNAs that mediate Notch signaling to regulate macrophage activation and tumor-associated macrophages (TAMs). In this study, we demonstrated that miR-148a-3p functions as a novel downstream molecule of Notch signaling to promote the differentiation of monocytes into macrophages in the presence of granulocyte macrophage colony-stimulating factor (GM-CSF). Meanwhile, miR-148a-3p promoted M1 and inhibited M2 polarization of macrophages upon Notch activation. Macrophages overexpressing miR-148a-3p exhibited enhanced ability to engulf and kill bacteria, which was mediated by excessive production of reactive oxygen species (ROS). Further studies using reporter assay and Western blotting identified Pten as a direct target gene of miR-148a-3p in macrophages. Macrophages overexpressing miR-148a-3p increased their ROS production through the PTEN/AKT pathway, likely to defend against bacterial invasion. Moreover, miR-148a-3p also enhanced M1 macrophage polarization and pro-inflammatory responses through PTEN/AKT-mediated upregulation of NF-κB signaling. In summary, our data establish a novel molecular mechanism by which Notch signaling promotes monocyte differentiation and M1 macrophage activation through miR-148a-3p, and suggest that miR-148a-3p-modified monocytes or macrophages are potential new tools for the treatment of inflammation-related diseases.

Inhibition of miR-32 activity promoted EMT induced by PM2.5 exposure through the modulation of the Smad1-mediated signaling pathways in lung cancer cells

Epithelial mesenchymal transition (EMT) is a crucial morphological event during tumor progression. The present study reported that EMT could be triggered by airborne fine particulate matter (PM) with a mean diameter of less than 2.5 μm (PM2.5) in human lung cancer cells. We also aimed to elucidate the possible mechanisms of these processes. The results showed that treatment with PM2.5 promoted the activity of the SMAD family member 1 (Smad1)-mediated signaling pathway and downregulated the expression of the inhibitory Smad proteins Smad6 and Smad7 in lung cancer cells. Moreover, the knockdown of Smad1 suppressed the EMT process induced by PM2.5 exposure. Our data further revealed that miR-32 has a negative effect on PM2.5-induced EMT. The results showed that the expression level of miR-32 was significantly upregulated in the PM2.5-induced EMT process. The knockdown of miR-32 enhances the activity of the Smad1-mediated signaling pathway, which promotes the EMT process induced by PM2.5. Thus, these findings indicate that PM2.5 can induce the EMT process through the Smad1-mediated signaling pathway, and miR-32 may act as an EMT inhibitor in lung cancer cells.

Identification of novel diagnostic and prognostic miRNA signatures in endometrial cancer

With the goal of identifying diagnostic and prognostic biomarkers in endometrial cancer, miRNA-profiling was carried out with formalin-fixed paraffin embedded (FFPE) tissue samples from 49 endometrial cancer patients. Results using an 84-cancer specific miRNA panel identified the upregulation of miR-141-3p and miR-96-5p along with a downregulation of miR-26, miR-126-3p, miR-23b, miR-195-5p, miR-374a and let-7 family of miRNAs in endometrial cancer. We validated the dysregulated expression of the identified miRNAs in a panel of endometrial cancer cell-lines. Immunohistochemical analysis of the tissue micro array derived from these patients established the functional correlation between the decreased expression of tumor suppressive miRNAs and their target oncogenes: ERBB2, EGFR, EPHA2, BAX, GNA12, GNA13, and JUN. Comparative analysis of the samples from the patients with extended progression-free survival (PFS) ( > 21 months) versus the patients with the PFS of < 21 months indicated increased expression of tumor suppressive miR-142-3p, miR-142-5p, and miR-15a-5p in samples from extended PFS patients. In addition to defining a specific set of miRNAs and their target genes as potential diagnostic biomarkers, our studies have identified tumor suppressive miR-142 cluster and miR-15a as predictors of favorable prognosis for therapy response in endometrial cancer.

The potential value of microRNA-4463 in the prognosis evaluation in hepatocellular carcinoma

The purpose of this study is to measure the expression of microRNA-4463 and microRNA-6087 between normal persons and patients with hepatocellular carcinoma (HCC), and to clarify the meaning of them in the prognosis evaluation in HCC. Forty-five samples from healthy people and patients, who had been diagnosed with hepatocellular carcinoma before any treatment, were collected to study respectively. Real-time PCR was used to detect the expression of miRNA-4463 and miRNA-6087 in the serum of control group and hepatocellular carcinoma patients. The expression of miR-4463 in the serum of HCC patients was significantly higher than that in control group (P < 0.05), and the expression level was independent of gender, tumor size, cell types, stages, alanine aminotransferase (ALT), aspartate aminotransferase (AST), total bilirubin (TBIL) and HBsAg status (P > 0.05). But there was a significant difference of different level of AFP in HCC (P < 0.05), and the difference between the group of AFP lower than 400 ug/l and the control group is statistically significant (P < 0.05). Besides, the survival time had showed a significant difference at the high and low expression levels (P < 0.05). But the expression level of miRNA-6087 was no difference in HCC and control group. The disorder of miRNA-4463 occurred in HCC, even the AFP level doesn't rises. What's more, patients who get the high level of miRNA-4463 seem to have a shorter survival time. And it contributes great to the prognostic evaluation. This is the first study to illustrate the potential significance of miRNA-4463 in the prognosis in HCC.

Non-digestible carbohydrates supplementation increases miR-32 expression in the healthy human colorectal epithelium: A randomized controlled trial

Colorectal cancer (CRC) risk is modulated by diet and there is convincing evidence of reduced risk with higher non‐digestible carbohydrates (NDCs) consumption. Resistant starch (RS), a NDC, positively modulates the expression of oncogenic microRNAs, suggesting that this could be a mechanism through which NDCs protect against CRC. The present study aimed to investigate the effects of supplementation with two NDCs, RS, and polydextrose (PD), on microRNA expression in the macroscopically‐normal human rectal epithelium using samples from the DISC Study, a randomized, double‐blind, placebo‐controlled dietary intervention. We screened 1008 miRNAs in pooled post‐intervention rectal mucosal samples from participants allocated to the double placebo group and those supplemented with both RS and PD. A total of 111 miRNAs were up‐ or down‐regulated by at least twofold in the RS + PD group compared with the control group. From these, eight were selected for quantification in individual participant samples by qPCR, and fold‐change direction was consistent with the array for seven miRNAs. The inconsistency for miR‐133b and the lower fold‐change values observed for the seven miRNAs is probably because qPCR of individual participant samples is a more robust and sensitive method of quantification than the array. miR‐32 expression was increased by approximately threefold (P = 0.033) in the rectal mucosa of participants supplemented with RS + PD compared with placebo. miR‐32 is involved in the regulation of processes such as cell proliferation that are dysregulated in CRC. Furthermore, miR‐32 may affect non‐canonical NF‐κB signaling via regulation of TRAF3 expression and consequently NIK stabilization.

MicroRNA-32 promotes calcification in vascular smooth muscle cells: Implications as a novel marker for coronary artery calcification

Cardiovascular calcification is one of the most severe outcomes associated with cardiovascular disease and often results in significant morbidity and mortality. Previous reports indicated that epigenomic regulation of microRNAs (miRNAs) might play important roles in vascular smooth muscle cell (VSMC) calcification. Here, we identified potential key miRNAs involved in vascular calcification in vivo and investigated the role of miR-32-5p (miR-32). According to microarray analysis, we observed increased expression of miR-125b, miR-30a, and miR-32 and decreased expression of miR-29a, miR-210, and miR-320 during the progression of vascularcalcification. Additionally, gain- and loss-of-function studies of miR-32 confirmed promotion of VSMC calcification in mice through the enhanced expression of bonemorphogenetic protein-2, runt-related transcription factor-2(RUNX2), osteopontin, and the bone-specific phosphoprotein matrix GLA protein in vitro. Moreover, miR-32 modulated vascularcalcification progression by activating phosphoinositide 3-kinase (PI3K)signaling and increasing RUNX2 expression and phosphorylation by targeting the 3'-untranslated region of phosphatase and tensin homolog Mrna (PTEN) in mouse VSMCs. Furthermore, we detected higher miR-32 levels in plasmafrom patients with coronary artery disease with coronary artery calcification (CAC) as compared with levels observed in non-CAC patients (P = 0.016), further confirming miR-32 as a critical modulator and potential diagnostic marker for CAC.

TLR-4/miRNA-32-5p/FSTL1 signaling regulates mycobacterial survival and inflammatory responses in Mycobacterium tuberculosis-infected macrophages

Macrophages play a pivotal role in host immune response against mycobacterial infection, which is tightly modulated by multiple factors, including microRNAs. The purpose of the present study was to investigate the biological function and potential mechanism of miR-32-5p in human macrophages during Mycobacterium tuberculosis (M.tb) infection. The results demonstrated that miR-32-5p was robustly enhanced in THP-1 and U937 cells in response to M.tb infection. TLR-4 signaling was required for upregulation of miR-32-5p induced by M.tb infection. Additionally, the introduction of miR-32-5p strongly increased the survival rate of intracellular mycobacteria, whereas inhibition of miR-32-5p suppressed intracellular growth of mycobacteria during M.tb challenged. Furthermore, forced expression of miR-32-5p dramatically attenuated the accumulation of inflammatory cytokines IL-1β, IL-6 and TNF-α induced by M.tb infection. Conversely, downregulated expression of miR-32-5p led to enhancement in these inflammatory cytokines. More importantly, our study explored that Follistatin-like protein 1 (FSTL1) was a direct and functional target of miR-32-5p. qRT-PCR and western blot analysis further validated that miR-32-5p negatively regulated the expression of FSTL1. Mechanistically, re-expression of FSTL1 attenuated the ability of miR-32-5p to promote mycobacterial survival. Meanwhile, miR-32-5p-mediated inhibition of the inflammatory cytokine production were completely reversed by overexpression of FSTL1. Collectively, our findings demonstrated a novel role of TLR-4/miRNA-32-5p/FSTL1 in the modulation of host defense against mycobacterial infection, which may provide a better understanding of the pathogenesis of tuberculosis and useful information for developing potential therapeutic interventions against the disease.

Shift of microRNA profile upon glioma cell migration using patient-derived spheroids and serum-free conditions

Glioblastoma multiforme (GBM) is the most frequent malignant primary brain tumor. A major reason for the overall median survival being only 14.6 months is migrating tumor cells left behind after surgery. Another major reason is tumor cells having a so-called cancer stem cell phenotype being therefore resistant towards traditional chemo- and radiotherapy. A group of novel molecular targets are microRNAs (miRNAs). MiRNAs are small non-coding RNAs exerting post-transcriptional regulation of gene expression. The aim of this study was to identify differentially expressed miRNAs in migrating GBM cells using serum-free stem cell conditions. We used patient-derived GBM spheroid cultures for a novel serum-free migration assay. MiRNA expression of migrating tumor cells isolated at maximum migration speed was compared with corresponding spheroids using an OpenArray Real-Time PCR System. The miRNA profiling revealed 30 miRNAs to be differentially expressed. In total 13 miRNAs were upregulated and 17 downregulated in migrating cells compared to corresponding spheroids. The three most deregulated miRNAs, miR-1227 (up-regulated), miR-32 (down-regulated) and miR-222 (down-regulated), were experimentally overexpressed. A non-significantly increased migration rate was observed after miR-1227 overexpression. A significantly reduced migration rate was observed after miR-32 and miR-222 overexpression. In conclusion a shift in microRNA profile upon glioma cell migration was identified using an assay avoiding serum-induced migration. Both the miRNA profiling and the functional validation suggested that miR-1227 may be associated with increased migration and miR-32 and miR-222 with decreased migration. These miRNAs may represent potential novel targets in migrating glioma cells.

Mechanisms for microRNAs in pathogenesis of hepatocellular carcinoma and challenges in their clinical application

Hepatocellular carcinoma (HCC) is one of the most deadly tumors worldwide, and it seriously endangers the health of people in China. Hepatocarcinogenesis is an extremely complex process that involves many risk factors. MicroRNAs (miRNAs) are a group of small, short and non-coding RNAs, and approximately one-third of human genes are regulated by miRNAs, which play important roles in tumor cell proliferation, cell cycle and apoptosis as well as tumor invasion, metastasis, and angiogenesis. Numerous studies have shown that miRNAs have a close relationship with hepatocarcinogenesis. In addition, miRNAs play a significant role in the diagnosis and therapy of HCC. In this review, we discuss the recent advances in the understanding of signaling pathways that are related to miRNAs in hepatocarcinogenesis, and the challenges faced in the clinical application of miRNAs.

The lncRNA SNHG5/miR-32 axis regulates gastric cancer cell proliferation and migration by targeting KLF4

Long noncoding RNAs (lncRNAs) are emerging as important regulators in cellular processes, including the development, proliferation, and migration of cancer cells. We have demonstrated in a prior study that small nucleolar RNA host gene 5 (SNHG5) is dysregulated in gastric cancer (GC). To further explore the underlying mechanisms of SNGH5 function in the development of GC, in this study, we screened the microRNAs interacting with SNHG5 and elucidated their roles in GC. We showed that SNHG5 contains a putative miR-32-binding site and that deletion of this site abolishes the responsiveness to miR-32. Suppression of SNHG5 expression by miR-32 was found to be Argonaute (Ago)2-dependent. Immunoprecipitation showed that SNHG5 could be pulled down from the Ago-2 complex with miR-32. Furthermore, it was reported that Kruppel-like factor 4 (KLF4) is a target gene of miR-32. In agreement with SNHG5 being a decoy for miR-32, we showed that KLF4 suppression by miR-32 could be partially rescued by SNHG5 overexpression, whereas miR-32 mimic rescued SNHG5 overexpression-mediated suppression of GC cell migration. In addition, we identified a negative correlation between the expression of SNHG5 and miR-32 in GC tissues. Furthermore, KLF4 expression was significantly downregulated in GC specimens, and a negative correlation between miR-32 and KLF4 expression and a positive correlation between KLF4 and SNHG5 expression levels were detected. Overall, this study demonstrated, for the first time, that the SNHG5/miR-32/KLF4 axis functions as an important player in GC cell migration and potentially contributes to the improvement of GC diagnosis and therapy.-Zhao, L., Han, T., Li, Y., Sun, J., Zhang, S., Liu, Y., Shan, B., Zheng D., Shi, J. The lncRNA SNHG5/miR-32 axis regulates gastric cancer cell proliferation and migration by targeting KLF4.

MicroRNA-107: a novel promoter of tumor progression that targets the CPEB3/EGFR axis in human hepatocellular carcinoma

MicroRNAs (miRNAs) are dysregulated in many types of malignancies, including human hepatocellular carcinoma (HCC). MiR-107 has been implicated in several types of cancer regulation; however, relatively little is known about miR-107 in human HCC. In the present study, we showed that the overexpression of miR-107 accelerates the tumor progression of HCC in vitro and in vivo through its new target gene, CPEB3. Furthermore, our results demonstrated that CPEB3 is a newly discovered tumor suppressor that acts via the EGFR pathway. Therefore, our study demonstrates that the newly discovered miR-107/CPEB3/EGFR axis plays an important role in HCC progression and might represent a new potential therapeutic target for HCC treatment.

The PTEN tumor suppressor gene and its role in lymphoma pathogenesis

The phosphatase and tensin homolog gene PTEN is one of the most frequently mutated tumor suppressor genes in human cancer. Loss of PTEN function occurs in a variety of human cancers via its mutation, deletion, transcriptional silencing, or protein instability. PTEN deficiency in cancer has been associated with advanced disease, chemotherapy resistance, and poor survival. Impaired PTEN function, which antagonizes phosphoinositide 3-kinase (PI3K) signaling, causes the accumulation of phosphatidylinositol (3,4,5)-triphosphate and thereby the suppression of downstream components of the PI3K pathway, including the protein kinase B and mammalian target of rapamycin kinases. In addition to having lipid phosphorylation activity, PTEN has critical roles in the regulation of genomic instability, DNA repair, stem cell self-renewal, cellular senescence, and cell migration. Although PTEN deficiency in solid tumors has been studied extensively, rare studies have investigated PTEN alteration in lymphoid malignancies. However, genomic or epigenomic aberrations of PTEN and dysregulated signaling are likely critical in lymphoma pathogenesis and progression. This review provides updated summary on the role of PTEN deficiency in human cancers, specifically in lymphoid malignancies; the molecular mechanisms of PTEN regulation; and the distinct functions of nuclear PTEN. Therapeutic strategies for rescuing PTEN deficiency in human cancers are proposed.

Identification of a Novel lincRNA-p21-miR-181b-PTEN Signaling Cascade in Liver Fibrosis

Previously, we found that long intergenic noncoding RNA-p21 (lincRNA-p21) inhibits hepatic stellate cell (HSC) activation and liver fibrosis via p21. However, the underlying mechanism of the antifibrotic role of lincRNA-p21 in liver fibrosis remains largely unknown. Here, we found that lincRNA-p21 expression was significantly downregulated during liver fibrosis. In LX-2 cells, the reduction of lincRNA-p21 induced by TGF-β1 was in a dose- and time-dependent manner. lincRNA-p21 expression was reduced in liver tissues from patients with liver cirrhosis when compared with that of healthy controls. Notably, lincRNA-p21 overexpression contributed to the suppression of HSC activation. lincRNA-p21 suppressed HSC proliferation and induced a significant reduction in α-SMA and type I collagen. All these effects induced by lincRNA-p21 were blocked down by the loss of PTEN, suggesting that lincRNA-p21 suppressed HSC activation via PTEN. Further study demonstrated that microRNA-181b (miR-181b) was involved in the effects of lincRNA-p21 on HSC activation. The effects of lincRNA-p21 on PTEN expression and HSC activation were inhibited by miR-181b mimics. We demonstrated that lincRNA-p21 enhanced PTEN expression by competitively binding miR-181b. In conclusion, our results disclose a novel lincRNA-p21-miR-181b-PTEN signaling cascade in liver fibrosis and suggest lincRNA-p21 as a promising molecular target for antifibrosis therapy.

Low Expression of Mir-137 Predicts Poor Prognosis in Cutaneous Melanoma Patients

BACKGROUND

The present study aimed to measure miR-137 expression in patients with cutaneous melanoma (CM) and to estimate the correlation of miR-137 expression and the prognosis of CM patients.

MATERIAL/METHODS

The expression level of miR-137 was assayed by quantitative real-time PCR (qRT-PCR) and presented as mean ±SD. Chi-square was used to evaluate the relationship between miR-137 expression and clinical characteristics. We used a Kaplan-Meier survival curve to determine the overall survival rate of CM patients. Moreover, the correlation between miR-137 expression and the prognosis of CM patients was confirmed by Cox regression analysis.

RESULTS

The relative expression of miR-137 in CM tissue was 1.59±0.43, while that in paired normal tissue was 2.41±0.54, which was significantly higher. Chi-square analysis showed statistical significance between miR-137 expression and clinical characteristics such as TNM stage, ulcer, and occurrence site (P<0.05). However, no association was found between miR-137 expression and age, sex, or family history (P>0.05). According to the survival curve outcome, patients with low miR-137 expression showed relatively higher mortality (P=0.000) and multivariate analysis verified that low expression of miR-137 predicted poor prognosis of CM patients (HR=8.531, 95% CI=2.950-24.668, P=0.000).

CONCLUSIONS

Compared with paired normal tissues, miR-137 expression was lower in CM tissues. Patients with low miR-137 expression had higher mortality than those with high miR-137 expression, suggesting that low miR-137 expression indicated poor prognosis for CM patients.

MiR-670-5p induces cell proliferation in hepatocellular carcinoma by targeting PROX1

MiRNAs, as oncogenes or as anti-oncogenes, play critically regulated roles in human cancers at posttranscriptional level. A number of dysregulated miRNAs has been observed in HCC. However, the expression and function of miR-670-5p have not been evaluated in HCC to date. In this study, we examined and confirmed the over-expression of miR-670-5p in HCC and in hepatoma-derived cells Hep3B. At least 60% of HCC tissues showed a greater than three-fold enhance in the expression of miR-670-5p compared with paired adjacent non-cancerous tissues. Knockdown studies for miR-670-5p showed that the expression of miR-670-5p promoted cellular proliferation. In tissues and cells with high expression of miR-670-5p, decreased expression of PROX1, a miR-670-5p predicated target, was detected. It confirmed that PROX1 expression was obviously affected by the expression of miR-670-5p. Furthermore, overexpression of PROX1 greatly inhibitted cellular proliferation. Therefore, it was inferred that miR-670-5p may play important roles in enhancing proliferation activity that is associated with HCC by modulating PROX1 expression at posttranscriptional level.

Focus on PTEN Regulation

The role of phosphatase and tensin homolog on chromosome 10 (PTEN) as a tumor suppressor has been for a long time attributed to its lipid phosphatase activity against PI(3,4,5)P₃, the phospholipid product of the class I PI3Ks. Besides its traditional role as a lipid phosphatase at the plasma membrane, a wealth of data has shown that PTEN can function independently of its phosphatase activity and that PTEN also exists and plays a role in the nucleus, in cytoplasmic organelles, and extracellularly. Accumulating evidence has shed light on diverse physiological functions of PTEN, which are accompanied by a complex regulation of its expression and activity. PTEN levels and function are regulated transcriptionally, post-transcriptionally, and post-translationally. PTEN is also sensitive to regulation by its interacting proteins and its localization. Herein, we summarize the current knowledge on mechanisms that regulate the expression and enzymatic activity of PTEN and its role in human diseases.