MicroRNAs involved in tumor suppressor and oncogene pathways: implications for hepatobiliary neoplasia

Autonomous Feedback-Driven Engineered DNAzyme-Coated Trojan Horse-like Nanocapsules for On-Demand CRISPR/Cas9 Delivery

Manipulating the expression of cellular genes through efficient CRISPR/Cas9 delivery is rapidly evolving into a desirable tumor therapeutics. The exposure of CRISPR/Cas9 to a complex external environment poses challenges for conventional delivery carriers in achieving responsive and accurate release. Here, we report a Trojan horse-like nanocapsule for the on-demand delivery of CRISPR/Cas9 in a microRNA-responsive manner, enabling precise tumor therapy. The nanocapsule comprises a nanoassembled, engineered DNAzyme shell encasing a Cas9/sgRNA complex core. The DNAzyme, functioning as a catalytic unit, undergoes a conformational change in the presence of tumor-associated microRNA, followed by activating a positive feedback-driven autonomous catabolic cycle of the nanocapsule shell. This catabolic cycle is accomplished through chain reactions of DNAzyme "cleavage-hybridization-cleavage", which ensures sensitivity in microRNA recognition and effective release of Cas9/sgRNA. Utilizing this Trojan horse-like nanocapsule, as low as 1.7 pM microRNA-21 can trigger the on-demand release of Cas9/sgRNA, enabling the specific editing of the protumorigenic microRNA coding gene. The resulting upregulation of tumor suppressor genes induces apoptosis in tumor cells, leading to significant inhibition of tumor growth by up to 75.94%. The Trojan horse-like nanocapsule, with superior programmability and biocompatibility, is anticipated to serve as a promising carrier for tailoring responsive gene editing systems, achieving enhanced antitumor specificity and efficacy.

A Mechanistic Review of Methotrexate and Celecoxib as a Potential Metronomic Chemotherapy for Oral Squamous Cell Carcinoma

The combination of low-dose methotrexate and celecoxib as metronomic chemotherapy (MCT) is a novel therapy, believed to act by modulating the immune response, inhibiting angiogenesis and its cytotoxic action, though the exact mechanism of action is unclear. Clinically, MCT was found to be very effective in delaying tumor progression in patients with head and neck squamous cell carcinoma in both curative and palliative settings. This review was aimed to give a brief insight into the mechanism of action and potential molecular alterations of MCT in the treatment of oral cancers taking into consideration the various in vivo and in vitro studies.

Looking at Thyroid Cancer from the Tumor-Suppressor Genes Point of View

Simple Summary

Thyroid cancer is the most common endocrine cancer. As tumor-suppressor genes (TSGs) are implicated in many different functions in the organism, their loss in cells in a normal tissue may drive their transformation into cancer cells. TSGs are generally classified into three subclasses: (i) gatekeepers that encode proteins involved in the control of cell cycle and apoptosis; (ii) caretakers that produce proteins implicated in maintaining genomic stability; and (iii) landscapers that, when mutated, create a suitable environment for neoplastic growth. Different inactivation mechanisms may suppress TSG function. Understanding these mechanisms and TSG alterations in thyroid tumors is of great importance for thyroid cancer prognosis, diagnosis, and therapy. The present review paper discusses TSG inactivation mechanisms and alterations in order to help to identify more efficient therapeutic modalities for thyroid cancer management.

Abstract

Thyroid cancer is the most frequent endocrine malignancy and accounts for approximately 1% of all diagnosed cancers. A variety of mechanisms are involved in the transformation of a normal tissue into a malignant one. Loss of tumor-suppressor gene (TSG) function is one of these mechanisms. The normal functions of TSGs include cell proliferation and differentiation control, genomic integrity maintenance, DNA damage repair, and signaling pathway regulation. TSGs are generally classified into three subclasses: (i) gatekeepers that encode proteins involved in cell cycle and apoptosis control; (ii) caretakers that produce proteins implicated in the genomic stability maintenance; and (iii) landscapers that, when mutated, create a suitable environment for malignant cell growth. Several possible mechanisms have been implicated in TSG inactivation. Reviewing the various TSG alteration types detected in thyroid cancers may help researchers to better understand the TSG defects implicated in the development/progression of this cancer type and to find potential targets for prognostic, predictive, diagnostic, and therapeutic purposes. Hence, the main purposes of this review article are to describe the various TSG inactivation mechanisms and alterations in human thyroid cancer, and the current therapeutic options for targeting TSGs in thyroid cancer.

MicroRNA-148a-3p inhibits progression of hepatocelluar carcimoma by repressing SMAD2 expression in an Ago2 dependent manner

Background

Hepatocellular carcinoma (HCC) is one of the most prevalent common cancer worldwide with high mortality. Transforming growth factor-β (TGF-β) signaling pathway was reported dysregulated during liver cancer formation and progression. As a key component of TGF-β signaling, the role of SMAD2 and its regulatory mechanisms in HCC remain unclear.

Methods

SMAD2 expression in paired HCC specimens were determined by western blot and immunohistochemistry (IHC). quantitative real-time PCR (qRT-PCR) was used to measure mRNA and microRNA (miRNA) expression level. Cell migration, invasion and proliferation ability were evaluated by transwell, CCK8 and EdU assay. In silico websites were used to manifest overall survival rates of HCC patients or to predict miRNAs targeting SMAD2. Dual luciferase reporter assay and anti-Ago2 immunoprecipitation assay were performed to confirm the binding between SMAD2 mRNA and miRNA-148a-3p (miR-148a). Tumorigenesis and lung metastasis mouse model were used to explore the role of miR-148a in vivo. In situ hybridization (ISH) was conducted to determine the expression of miR-148a in liver tissues.

Results

In this study, we found that SMAD2 was highly expressed in HCC and elevated SMAD2 expression predicted shorter overall survival (OS) time for HCC patients. SMAD2 promoted mobility and proliferation of HCC cells in vitro. We further revealed that the expression of miR-148a was negatively correlated with SMAD2 and found that miR-148a repressed SMAD2 expression by downregulating its mRNA through binding with Argonaute 2 (Ago2) in HCC. Transwell, CCK8 and animal experiments exhibited miR-148a inhibited metastasis and proliferation of HCC in vitro and in vivo. Moreover, the phenotype changes caused by miR-148a manipulation were recovered by rescuing SMAD2 expression in HCC cells. ISH assay indicated miR-148a was downregulated in HCC and low expression of miR-148a associated with more aggressive clinic features and poor prognosis.

Conclusion

miR-148a was identified as a repressor of HCC progression by downregulating SMAD2 in an Ago2 dependent manner.

Sevoflurane Inhibits Proliferation, Invasion, but Enhances Apoptosis of Lung Cancer Cells by Wnt/β-catenin Signaling via Regulating lncRNA PCAT6/miR-326 Axis

Sevoflurane was frequently used as a volatile anesthetic in cancer surgery. However, the potential mechanism of sevoflurane on lung cancer remains largely unclear. In this study, lung cancer cell lines (H446 and H1975) were treated by various concentrations of sevoflurane. 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assessment and colony formation assay were performed to detect the cell viability and proliferation, separately. Also, transwell assay or flow cytometry assay was applied as well to evaluate the invasive ability or apoptosis in lung cancer cells, respectively. Western blot assay was employed to detect the protein levels of β-catenin and Wnt5a. Moreover, quantitative real-time polymerase chain reaction (qRT-PCR) was used to examine the expression level of prostate cancer-associated transcript 6 (PCAT6) and miR-326 in lung cancer tissues and cells. The target interaction between miR-326 and PCAT6 or Wnt5a was predicted by bioinformatics analysis and verified by the dual-luciferase reporter gene assay. Sevoflurane inhibited the abilities on viability, proliferation, invasion, and activation of Wnt/β-catenin signaling, but promoted apoptosis of H446 and H1975 cells in a dose-dependent manner. The expression of PCAT6 was increased in lung cancer tissues and cells, except for that of miR-326. Besides, sevoflurane could lead to expressed limitation of PCAT6 or improvement of miR-326. This process presented a stepwise manner. Up-regulation of PCAT6 restored the suppression of sevoflurane on abilities of proliferation, invasion, rather than apoptosis, and re-activated the Wnt5a/β-catenin signaling in cells. Moreover, the putative binding sites between miR-326 and PCTA6 or Wnt5a were predicted by starBase v2.0 software online. PCAT6 suppressing effects on cells could be reversed by pre-treatment with miR-326 vector. The promotion of Wnt5a inverted effects led from miR-326 or sevoflurane. Our study indicated that sevoflurane inhibited the proliferation, and invasion, but enhanced the apoptosis in lung cancer cells by regulating the lncRNA PCAT6/miR-326/Wnt5a/β-catenin axis.

Role of miR-18a and miR-25 disruption and its mechanistic pattern in progression of liver cancer

This study examined the molecular mechanisms underlying the roles of the microRNAs miR-18a and miR-25 in the progression of human liver cancer. Liver cancer biopsies obtained from early-stage liver cancer patients were examined by qRT-PCR and Northern blotting to examine the expression of miR-18a and miR-25. Both microRNAs were overexpressed in mouse primary hepatocytes following transfection of the cells with vectors encoding the microRNAs. An analysis of biopsy samples from liver cancer patients indicated that both miR-18a and miR-25 were overexpressed during the early stages of liver cancer. Further, qRT-PCR and Northern blotting confirmed that both of these microRNAs play crucial roles in the progression of liver cancer. Our findings clearly indicate that miR-18a and miR-25 can be used as prognostic biomarkers for early-stage liver cancer. Hence, miR-18a and miR-25 may have value as prognostic indicators and may facilitate the development of novel therapeutics for liver cancer.

MicroRNA-2053 overexpression inhibits the development and progression of hepatocellular carcinoma

MicroRNAs (miRNAs) represent a class of small RNAs that participate in the regulation of tumor progression. However, the identification of functional miRNAs in tumors has not been thoroughly elucidated. In the present study we aim to investigate the impact of altered miR-2053 expression in hepatocellular carcinoma (HCC) cells. The results of the present study demonstrated that miR-2053 overexpression inhibited cell proliferation, migration and invasion, and promoted apoptosis in a HCC cell line, while miR-2053 knockdown induced the opposite cellular phenotypic changes. Mechanistically, it was found that overexpression of miR-2053 resulted in the downregulation of the phosphoinositide 3-kinase (PI3K) and Wnt/β-catenin signaling pathways, which are aberrantly expressed in HCC. Collectively, the results indicate that miR-2053 serves as a tumor suppressor with a crucial role in inhibiting the proliferation, migration and invasion of HCC via targeting the PI3K and Wnt/β-catenin signaling pathways. These data indicate a potential application of miR-2053 in cancer therapy.

p53-dependent upregulation of miR-16-2 by sanguinarine induces cell cycle arrest and apoptosis in hepatocellular carcinoma

MicroRNAs (miRNAs) were involved in cancer progression, and the targeting of miRNAs by natural agents has opened avenues for cancer treatment and drug development. miR-16 functions as a tumor suppressor and is frequently deleted or downregulated in various human cancers, including hepatocellular carcinoma (HCC). In the present study, we employed a miR-16-responsive luciferase reporter to screen candidate compounds that modulate miR-16 expression from a natural product library. One compound, sanguinarine (SG), was capable of activating miR-16 in HCC cells with wildtype or mutated p53 expression but not in p53-deleted HCC cells. Mechanistic investigations revealed that SG increased p53 occupancy on the miR-16-2 promoter and decreased the expression of miR-16 target genes, including Bcl-2 and cyclin D1. Moreover, SG significantly inhibited HCC cell proliferation in a p53-dependent manner by inducing cell cycle arrest and reactive oxygen species (ROS)-associated apoptosis. Silencing miR-16 by treatment with anti-miR16 miRNA inhibitors rescued the cell viability repression effect caused by SG. Importantly, SG dramatically suppressed tumor growth in an HCC xenograft model, with little cytotoxicity. Taken together, our results provide a preclinical proof-of-concept for SG as a potential strategy for HCC treatment based on the restoration of miR-16 tumor suppressor function.

Cholangiocarcinoma therapy with nanoparticles that combine downregulation of MicroRNA-210 with inhibition of cancer cell invasiveness

Cholangiocarcinoma (CCA) is the second most common primary liver malignancy with extremely poor therapeutic outcome due to high drug resistance, widespread metastasis and lack of effective treatment options. CCA progression and metastasis are regulated by multiple biological factors including multiple miRNAs and chemokine receptor CXCR4. The goal of this study was to test if nanotherapeutic blockade of CXCR4 by polymeric CXCR4 antagonist (PCX) combined with inhibition of hypoxia-inducible miR-210 cooperatively enhances therapeutic efficacy in CCA through reducing invasiveness, inducing cell killing, and reversing drug resistance. Methods: We first tested the activity of PCX to inhibit migration of CCA cells. We then prepared PCX/anti-miRNA nanoparticles and analyzed their miRNA delivery efficacy and anticancer activity in vitro. Finally, in vivo biodistribution assay and anticancer activity study were performed in CCA tumor-bearing mice. Results: Our results show that PCX had a broad inhibitory effect on cell migration, effectively delivered anti-miR-210, and downregulated miR-210 expression in CCA cells. Combination PCX/anti-miR-210 nanoparticles showed cytotoxic activity towards CCA cells and reduced the number of cancer stem-like cells. The nanoparticles reversed hypoxia-induced drug resistance and sensitized CCA cells to standard gemcitabine and cisplatin combination treatment. Systemic intravenous treatment with the nanoparticles in a CCA xenograft model resulted in prominent combined antitumor activity. Conclusion: Our findings support PCX-based nanoparticles as a promising delivery platform of therapeutic miRNA in combination CCA therapies.

Aberrant promoter methylation status is associated with upregulation of the E2F4 gene in breast cancer

E2F4 is an important basal transcription factor with the potential to promote tumor growth. Its upregulation in various types of cancer has been linked to numerous genetic factors; however, the nature of the involvement of epigenetic mechanisms, including DNA methylation, remains elusive. In the present study, E2F4 expression profiles were determined in 100 paired breast tumor and control samples, through RT-qPCR using the SYBR^® green method. Furthermore, the E2F4 promoter methylation status in each of these samples was assessed using methylation specific PCR, in order to evaluate its impact on gene expression. A two-fold increase in E2F4 gene expression was observed in the breast tumors compared with in their respective controls (P=0.022); of these tumors, ~72% were under-methylated. The change in methylation status was also significantly higher (P<0.001) in the tumor samples. Methylation status was negatively correlated (r=-30) with E2F4 expression profiles, indicating that a decrease in methylation may promote higher expression of E2F4. The two study cohorts (>45 and ≤45 years) had comparable methylation profiles, though they had significantly decreased methylation status compared with controls. Various histo-pathological types also have different methylation profiles, indicating the presence of a tissue specific methylation signature. The results of the present study demonstrated that E2F4 methylation status can have a notable influence on its expression, and that it may have prognostic value in breast carcinogenesis.

C-Myc-dependent repression of two oncogenic miRNA clusters contributes to triptolide-induced cell death in hepatocellular carcinoma cells

BACKGROUND

Triptolide is a structurally unique diterpene triepoxide with potent antitumor activity. However,the effect and mechanism of triptolide on hepatocellular carcinoma (HCC) is not well studied.

METHODS

Cells were treated with triptolide, and the anti-HCC activity of triptolide was evaluated using flow cytometry, western blot, and xenograft studies. MicroRNA microarray and quantitative reverse-transcription polymerase chain reaction was used to identify differential microRNAs induced by triptolide. Chromatin immunoprecipitation assay was employed to study the interaction between c-Myc and genomic regions of miR106b-25. MicroRNAs overexpression and knockdown experiments were performed to determine the role of these microRNAs in triptolide-induced apoptosis.

RESULTS

Triptolide inhibited cell proliferation and induced marked apoptosis in multiple HCC cell lines with different p53 status. Several signaling molecules involved in different pathways were altered after the treatment of triptolide. Xenograft tumor volume was significantly reduced in triptolide-treated group compared with vehicle control group. Two miRNA clusters, miR-17-92 and miR-106b-25, were significantly suppressed by triptolide, which resulted in the upregulation of their common target genes, including BIM, PTEN, and p21. In HCC samples, high levels of these miRNA clusters correlated with shorter recurrence free survival. Triptolide inhibited the expression of theses miRNAs in a c-Myc-dependent manner, which enhanced triptolide-induced cell death. We further showed that triptolide down-regulated the expression of c-Myc through targeting ERCC3, a newly identified triptolide-binding protein.

CONCLUSIONS

The triptolide-induced modulation of c-Myc/miRNA clusters/target genes axis enhances its potent antitumor activity, which indicates that triptolide serves as an attractive chemotherapeutic agent against HCC.

The regulation and function of microRNA-377/RASSF8 signaling axis in gastric cancer

Gastric cancer is a major cause of cancer-associated mortality worldwide. The aberrant expression of microRNA (miRNA) is involved in tumorigenesis. Ras proteins transfer information from the extracellular environment to internal cellular compartments and are essential in numerous signal transduction pathways. To investigate the regulation, function and clinical significance of the miRNA377/Ras association domain family (RASSF) 8 signaling axis in gastric cancer, reverse transcription-quantitative polymerase chain reaction, immunohistochemistry, cell counting kit-8, western blotting, and Transwell assays were used. The results revealed that expression of RASSF8 was significantly upregulated in normal gastric tissues compared with gastric cancer, which was further confirmed by immunohistochemical analysis, and its expression level was increased in normal gastric cells compared with gastric cancer cell lines. However, the expression of miR-377 was significantly upregulated in gastric cancer compared with normal gastric tissues. In addition, RASSF8 overexpression in BGC-823 gastric cancer cells significantly inhibited the proliferation, apoptosis and invasive abilities of cells. Whereas miR-377 attenuated these effects due to downregulated RASSF8 expression by directly targeting its 3′-untranslated region. Furthermore, in the current study, miR-377 was not able to reverse the effects of RASSF8 overexpression on gastric cancer cells. Collectively, the RASSF8 gene may represent a novel molecular target involved in gastric cancer development and may be useful in targeted therapy of patients with gastric cancer.

Diagnostic value of strand-specific miRNA-101-3p and miRNA-101-5p for hepatocellular carcinoma and a bioinformatic analysis of their possible mechanism of action

There is accumulating evidence that miRNA might serve as potential diagnostic and prognostic markers for various types of cancer. Hepatocellular carcinoma (HCC) is the most common type of malignant lesion but the significance of miRNAs in HCC remains largely unknown. The present study aimed to establish the diagnostic value of miR-101-3p/5p in HCC and then further investigate the prospective molecular mechanism via a bioinformatic analysis. First, the miR-101 expression profiles and parallel clinical parameters from 362 HCC patients and 50 adjacent non-HCC tissue samples were downloaded from The Cancer Genome Atlas (TCGA). Second, we aggregated all miR-101-3p/5p expression profiles collected from published literature and the Gene Expression Omnibus and TCGA databases. Subsequently, target genes of miR-101-3p and miR-101-5p were predicted by using the miRWalk database and then overlapped with the differentially expressed genes of HCC identified by natural language processing. Finally, bioinformatic analyses were conducted with the overlapping genes. The level of miR-101 was significantly lower in HCC tissues compared with adjacent non-HCC tissues (P < 0.001), and the area under the curve of the low miR-101 level for HCC diagnosis was 0.925 (P < 0.001). The pooled summary receiver operator characteristic (SROC) of miR-101-3p was 0.86, and the combined SROC curve of miR-101-5p was 0.80. Bioinformatic analysis showed that the target genes of both miR-101-3p and miR-101-5p are involved in several pathways that are associated with HCC. The hub genes for miR-101-3p and miR-101-5p were also found. Our results suggested that both miR-101-3p and miR-101-5p might be potential diagnostic markers in HCC, and that they exert their functions via targeting various prospective genes in the same pathways.

HnRNPK/miR-223/FBXW7 feedback cascade promotes pancreatic cancer cell growth and invasion

Several studies have identified miR-223 critically involved in various types of cancer, including pancreatic ductal adenocarcinoma (PDAC). However, its action and regulatory mechanisms in PDAC remains largely unclear. In this study, we found that the expression levels of miR-223 were increased in clinical samples with PDAC (81.6%). The upregulation of miR-223 increases the proliferation, migration, and invasive abilities of PDAC cells in vitro and in vivo. Mechanistically, miR-223 directly targeted FBXW7 and overexpression of FBXW7 reverted miR-223- induced drastic proliferation in PDAC cells. Interestingly, miR-223 promoter was found to form a coprecipitable complex with hnRNPK, and siRNA knockdown of hnRNPK in PDAC cells reduced the levels of miR-223. These results show that hnRNPK is a cellular protein that binds and affects the accumulation of miR-223 in PDAC. Furthermore, FBXW7 interacts with hnRNPK and promotes its degradation, which requires phosphorylation of hnRNPK at threonine 1695 by GSK3. Consistently, we observed an inverse expression pattern between FBXW7 and miR-223, whereas a positive expression pattern between miR-223 and hnRNPK was found in human PDAC tissues. These data unveiled an important new miR-223/FBXW7/HnRNPK feedback cascade in human PDAC.

The Enigma of miRNA Regulation in Cancer

MicroRNAs (miRNAs or miRs) are small 19-22 nucleotide long, noncoding, single-stranded, and multifunctional RNAs that regulate a diverse assortment of gene and protein functions that impact on a vast network of pathways. Lin-4, a noncoding transcript discovered in 1993 and named miRNA, initiated the exploration of research into these intriguing molecules identified in almost all organisms. miRNAs interfere with translation or posttranscriptional regulation of their target gene and regulate multiple biological actions exerted by these target genes. In cancer, they function as both oncogenes and tumor suppressor genes displaying differential activity in various cellular contexts. Although the role of miRNAs on target gene functions has been extensively investigated, less is currently known about the upstream regulatory molecules that regulate miRNAs. This chapter focuses on the factors and processes involved in miRNA regulation.

Interaction of microRNA-21/145 and Smad3 domain-specific phosphorylation in hepatocellular carcinoma

MicroRNAs 21 and 145 exhibit inverse expression in Hepatocellular carcinoma (HCC), but how they relate to Smad3 C-terminal and Link region phosphorylation (pSmad3C and pSmad3L) downstream of TGF-β/MAPK signaling, remains inconclusive. Our results suggest microRNA-145 targets Smad3 in HepG2 cells. Decreased tumor volume and increased apoptosis were produced in both microRNA-21 antagomir and microRNA-145 agomir groups compared to controls. Inhibition of TβRI and MAPK (ERK, JNK, and p38) activation respectively produced decreased microRNA-21 but increased microRNA-145 expression. Correspondingly, the expression level of pSmad3C obviously increased while pSmad3L decreased in microRNA-145 agomir-group and the expression of pSmad3C/3L were not markedly changed but pERK, pJNK, pp38 decreased in microRNA-21 antagomir-group compared to controls. On the other hand, microRNA-145 and 21 increased respectively in xenografts of HepG2 cells transfected with Smad3 EPSM and 3S-A plasmid, and this correlated with the overexpression of pSmad3C and pSmad3L respectively compared to control. To conclude, microRNA-21 promotes tumor progression in a MAPK-dependent manner while microRNA-145 suppresses it via domain-specific phosphorylation of Smad3 in HCC. Meanwhile, increased pSmad3C/3L lead to the up-regulation of microRNA-145/21 respectively. The interaction between pSmad3C/3L and microRNA-145/21 regulates HCC progression and the switch of pSmad3C/3L may serve as an important target for HCC therapy.

Transforming Cancer Epigenetics Using Nutritive Approaches and Noncoding RNAs

Cancer is considered one of the leading causes of death in the United States. Although preventive strategies, early detection, and improved treatment options have been developed, novel targets and therapeutics are still needed. Since concluding that cancer is mediated by genetic and epigenetic alterations of the cell, many research groups are now focusing on other means of prevention and therapy via nutrition, epigenetic mechanisms, and non-coding RNAs which have been shown to control gene expression and have many different functions at the cellular level. With the advent of high-throughput sequencing in human cancer, the potential to identify novel biomarkers and therapeutic targets of disease has increased tremendously and led to the identification of many non-coding RNAs that are dysregulated in various cancers. Gene expression and regulation is important in maintaining the homeostasis of normal tissues and cells. Not uncommonly, up- or down-regulation of particular genes are associated with cancer as a result of increased or decreased expression of transcriptional targets. This review focuses on the role of nutrition in cancer and the dysregulation of non-coding RNAs with particular emphasis on long non-coding RNAs and microRNAs in different cancer types.

Pigmy MicroRNA: surveillance cops in Therapies kingdom

MicroRNAs (miRNAs) are well preserved in every animal. These pigmy sized non-coding RNAs (21-23 nt), scattered in genome, are responsible for micromanaging the versatile gene regulations. Involvement of miRNAs was surveillance cops in all human diseases including cardiovascular defects, tumor formation, reproductive pathways, and neurological and autoimmune disorders. The effective functional role of miRNA can be reduced by chemical entities of antisense oligonucleotides and versatile small molecules that support the views of novel therapy of different human diseases. In this study, we have updated our current understanding for designing and synthesizing miRNA-controlling therapeutic chemicals. We have also proposed various in-vivo delivery strategies and their ongoing challenges to combat the incorporation hurdles in live cells and animals. Lastly, we have demonstrated the current progress of miRNA modulation in the treatment of different human diseases that provides an alternative approach of gene therapy.

MiR-24-3p enhances cell growth in hepatocellular carcinoma by targeting metallothionein 1M

Dysregulation of microRNAs has been demonstrated to contribute to malignant progression of cancers, including hepatocellular carcinoma (HCC). MiR-24-3p was previously reported to be significantly upregulated in HCC. However, the potential role and mechanism of action of miR-24-3p in the initiation and progression of HCC remain largely unknown. Quantitative reverse transcription polymerase chain reaction demonstrated that miR-24-3p was significantly upregulated in HCC tumor tissues compared with nontumor tissues. The cell viability, colony formation assay, and tumorigenicity assays in nude mice showed that miR-24-3p could enhance HCC cell growth in vitro and in vivo. Metallothionein 1M was verified as an miR-24-3p target gene by using dual-luciferase reporter assays, quantitative reverse transcription polymerase chain reaction, and Western blotting, which was involved in miR-24-3p regulated HCC cell growth. These results indicated that miR-24-3p plays an important role in the initiation and progression of HCC by targeting metallothionein 1M, and the miR-24-3p/metallothionein 1M pathway may contribute to the development of novel therapeutic strategies for HCC in the future.

Serum miR-21, miR-26a and miR-101 as potential biomarkers of hepatocellular carcinoma

AIM

This study aimed to investigate the expressions of serum miR-21, miR-26a and miR-101 in hepatocellular carcinoma (HCC) and their diagnostic value.

METHODS

Serum levels of miR-21, miR-26a and miR-101 were detected by quantitative real-time polymerase chain reaction (qRT-PCR) in 52 HCC patients, 42 chronic hepatitis (CH) patients and 43 healthy controls. ROC curve analysis was performed to evaluate the diagnostic value. Clinical parameters were collected.

RESULTS

Serum level of miR-21 was higher while miR-26a and miR-101 were significantly lower in HCC patients than those in healthy controls (P<0.05, P<0.001 and P<0.05, respectively). Serum levels of miR-26a and miR-101 were significantly lower in HCC patients than those in CH patients (P<0.001 and P<0.05). ROC curve analyses revealed that miR-21, miR-26a and miR-101 could differentiate HCC patients from healthy controls, the area under ROC curve (AUC) were 0.621 (67.4% sensitivity and 55.8% specificity), 0.754 (51.9% sensitivity and 95.2% specificity) and 0.631 (47.1% sensitivity and 81% specificity), respectively. Combination of miRNAs and alpha-fetoprotein (AFP) yielded an AUC of 0.914 with 87.0% sensitivity and 78.0% specificity. miR-26a and miR-101 had diagnostic potential for differentiating HCC from CH with AUC of 0.762 (75% sensitivity and 70% specificity) and 0.623 (54.9% sensitivity and 76.9% specificity). Combination of miR-26a, miR-101 and AFP yielded an improved AUC than AFP alone (0.854 vs. 0.683). Notably, miR-26a could differentiate small tumors HCC (≤3cm) from CH with an AUC of 0.753 (80% sensitivity and 62.5% specificity).

CONCLUSIONS

Serum miR-21, miR-26a and miR-101 are deregulated in HCC and can serve as potential biomarkers. Combination of these miRNAs and AFP provide a better detection than AFP alone. Serum miR-26a is a promising biomarker for early detection of HCC.

Diagnostic value of miRNA-96-5p/3p in dysplastic nodules and well-differentiated small hepatocellular carcinoma

AIM

Hepatocarcinogenesis is a multistep process from cirrhosis through low-grade dysplastic nodule, high-grade dysplastic nodule to hepatocellular carcinoma. Differential diagnosis between high-grade dysplastic nodules and early hepatocellular carcinomas is particularly difficult. The present study aims to identify a novel biological marker for differential diagnosis of the two lesions.

METHODS

The expression level of an miRNA pair, miRNA-96-5p and 3p, was assessed by reverse transcription polymerase chain reaction in hepatic tissues.

RESULTS

We showed that mature miRNA-96-5p and passenger strand miRNA-96-3p were differentially expressed in multistep hepatocarcinogenesis. miRNA-96-5p was significantly upregulated from cirrhosis, dysplastic nodules to hepatocellular carcinoma. However, significance of determination of miRNA-96-5p expression level for differential diagnosis between high-grade dysplastic nodule and hepatocellular carcinoma is limited. In contrast, the expression of miRNA-96-3p was detectable in cirrhosis and dysplastic nodules. Also, it was completely undetectable in the majority of hepatocellular carcinomas (30/34, 88.2%). The sensitivity and specificity of miRNA-96-3p negative expression for differential diagnosis of hepatocellular carcinomas from high-grade dysplastic nodules were 88.2% and 84.2%, respectively. In addition, a more specific diagnosis could be carried out by combining miRNA-96-3p with glypican 3, with the specificity of 100%.

CONCLUSION

These findings demonstrated that miRNA-96-3p is a helpful diagnostic biomarker in differential diagnosis between high-grade dysplastic nodules and well-differentiated small hepatocellular carcinomas, especially in combination with glypican 3.

Role of microRNA in liver regeneration

BACKGROUND

Liver regeneration is a complex process. microRNAs (miRNAs) are short, single-stranded RNAs that modify gene expression at the post-transcriptional level. Recent investigations have revealed that miRNAs are closely linked to liver regeneration.

DATA SOURCES

All included studies were obtained from PubMed, Embase, the ScienceDirect databases and Web of Science, with no limitation on publication year. Only studies published in English were considered.

RESULTS

We grouped studies that involved miRNA and liver regeneration into two groups: miRNAs as promoters and as inhibitors of liver regeneration. We summarized the relevant miRNAs separately from the related pathways.

CONCLUSIONS

Blocking or stimulating the pathways of miRNAs in liver regeneration may be novel therapeutic strategies in future regeneration-related liver managements. We may discover additional chemotherapy targets of miRNA.

Delivery of miR-200c Mimic with Poly(amido amine) CXCR4 Antagonists for Combined Inhibition of Cholangiocarcinoma Cell Invasiveness

Cholangiocarcinoma is the second most common primary liver malignancy with extremely poor prognosis due to early invasion and widespread metastasis. The invasion and metastasis are regulated by multiple factors including CXCR4 chemokine receptor and multiple microRNAs. The goal of this study was to test the hypothesis that inhibition of CXCR4 combined with the action of miR-200c mimic will cooperatively enhance the inhibition of the invasion of human cholangiocarcinoma cells. The results show that CXCR4-inhibition polycation PCX can effectively deliver miR-200c mimic and that the combination treatment consisting of PCX and miR-200c results in cooperative antimigration activity, most likely by coupling the CXCR4 axis blockade with epithelial-to-mesenchymal transition inhibition in the cholangiocarcinoma cells. The ability of the combined PCX/miR-200c treatment to obstruct two migratory pathways represents a promising antimetastatic strategy in cholangiocarcinoma.

The Spectrum of E2F in Liver Disease--Mediated Regulation in Biology and Cancer

Uncoordinated cell growth is one of the fundamental concepts in carcinogenesis and occurs secondary to dysregulation of the cell cycle. The E2Fs are a large family of transcription factors and are key regulators of the cell cycle. The activation of E2Fs is intimately regulated by retinoblastoma 1 (RB1). The RB pathway has been implicated in almost every human malignancy. Recently there have been exciting developments in the E2F field using animal models to better understand the role of E2Fs in vivo. Genetic mouse models have proven essential in implicating E2Fs in hepatocellular carcinoma (HCC) and liver disease. In this review, the general structure and function of E2Fs as well as the role for E2Fs in the development of HCC and liver disease is evaluated. Specifically, what is known about E2Fs in human disease is explored in depth, and future directions are discussed.

Endothelial progenitors promote hepatocarcinoma intrahepatic metastasis through monocyte chemotactic protein-1 induction of microRNA-21

OBJECTIVES

Endothelial progenitor cells (EPCs) circulate with increased numbers in the peripheral blood of patients with highly-vascularised hepatocellular carcinoma (HCC) and contribute to angiogenesis and neovascularisation. We hypothesised that angiogenic EPCs, that is, colony forming unit-endothelial cells (CFU-ECs), and outgrowth EPCs, that is, endothelial colony-forming cells, may exert paracrine effects on the behaviours and metastatic capacities of human hepatoma cells.

DESIGN

Various molecular and functional approaches ranging from in vitro cell culture studies on molecular signalling to in vivo investigations on cell invasion and orthotropic transplantation models in mice and clinical specimens from patients with HCC were used.

RESULTS

Monocyte chemotactic protein-1 (MCP-1) was identified as a critical mediator released from CFU-ECs to contribute to the chemotaxis of Huh7 and Hep3B cells by inducing their microRNA-21 (miR-21) biogenesis through the C-C chemokine receptor-2/c-Jun N-terminal kinase/activator protein-1 signalling cascade. CFU-EC-induction of miR-21 in these cells activated their Rac1 and matrix metallopeptidase-9 by silencing Rho GTPase-activating protein-24 and tissue inhibitor of metalloproteinase-3, respectively, leading to increased cell mobility. MCP-1-induction of miR-21 induced epithelial-mesenchymal transformation of Huh7 cells in vitro and their intrahepatic metastatic capability in vivo. Moreover, increased numbers of MCP-1(+) EPCs and their positive correlations with miR-21 induction and metastatic stages in human HCC were found.

CONCLUSIONS

Our results provide new insights into the complexity of EPC-HCC interactions and indicate that anticancer therapies targeting either the MCP-1 released from angiogenic EPCs or the miR-21 biogenesis in HCC cells may prevent the malignant progression of primary tumours.

Genetic alteration regulated by microRNAs in biliary tract cancers

Biliary tract cancers (BTCs) constitute a relatively rare but highly malignant class of tumors with poor prognosis including gallbladder cancer, intra- and extra-hepatic cholangiocarcinoma. Recently, accumulated evidences have demonstrated that deregulated expression of microRNAs (miRNAs) is closely associated with the development, invasion, metastasis and prognosis of different cancers including BTCs. MiRNAs comprise an endogenously expressed and highly evolutionarily conserved group of small, non-coding, single-stranded RNAs which negatively regulate target genes expression by means of combining with 3' untranslated region (UTR) of corresponding mRNAs at the post-transcriptional level with significant roles in various fundamental cellular procedures including cell proliferation, differentiation, migration, cell cycle control and apoptosis. Recent studies have indicated that miRNAs could function as novel tumor-promoting genes or tumor suppressor genes to act as potential therapeutic targets in anticancer treatment because the genetic alteration regulated by miRNAs could result in tumorigenesis and tumor inhibition. Anomalous miRNAs expression patterns, acting as phenotypic signatures of distinct cancers, are promising to be used as diagnostic, prognostic, predictive biomarkers. In this review, we summarize the current findings from the studies about potential genetic alteration regulated by miRNAs and their roles in BTCs.

Differentially expressed MicroRNAs provide mechanistic insight into fibrosis-associated liver carcinogenesis in mice

Hepatocellular carcinoma (HCC) is one of the most prevalent human cancers, with a rising incidence worldwide. The molecular mechanisms associated with the development of HCC are complex and include multiple interconnected molecular alterations with mounting evidence indicating an important role of microRNAs (miRNAs) in the pathogenesis of HCC. In humans, the development of HCC is commonly associated with liver cirrhosis. To study fibrosis-associated liver carcinogenesis, we used a mouse model designed to emulate the development of HCC in cirrhotic liver. Specifically, we were interested in evaluating the role of miRNAs in the molecular pathogenesis of liver carcinogenesis in male B6C3F1/J mice treated with N-nitrosodiethylamine (DEN) or carbon tetrachloride (CCl4 ) alone or a combination of DEN and CCl4 and characterized by a differential tumor incidence that increased in the following order: DEN<CCl4 <DEN+CCl4 . Treatment with DEN alone had negligible effect on hepatic miRNA expression. In contrast, treatment with either CCl4 alone or a combination of DEN and CCl4 resulted in major changes in miRNA expression. The analysis of miRNA profiles demonstrated an involvement of dysregulated miRNAs in major processes associated with the development of liver tumors, including inflammation, fibrosis, and stem cell activation. Importantly, the greatest incidence of liver tumors in mice treated with DEN+CCl4 was accompanied by a distinct over-expression of miRNAs suggesting that miRNA alterations may be responsible, at least in part, for the high tumor incidence.

The "Macro" World of microRNAs in Hepatocellular Carcinoma

Hepatotropic viruses such as hepatitis B virus (HBV) and hepatitis C virus (HCV) are the major etiological agents associated with development of hepatocellular carcinoma (HCC). Progression of HCC is a multistep process that requires sequential or parallel deregulation of oncogenic and tumor suppressive pathways leading to chromosomal instability and neoplastic phenotype. In the recent years, microRNAs (miRNAs) have carved their own niche alongside oncogenes and tumor suppressors, owing to their innate ability to receive and relay multiple signals. Not surprisingly, miRNAs are fast emerging as central player in myriads of malignancies including HCC. miRNAs are reported to participate in initiation and progression of HCC, and have also been clinically correlated with risk assessment, disease grade, aggressiveness, and prognosis. Despite extensive data available on the role of miRNAs in HCC, there is a pressing need to integrate and evaluate these datasets to find its correlation, if any, with causal agents in order to devise novel interventional modalities. Through this review, we attempt to bridge the gap by consolidating the current knowledge and concepts in the field of HCC-related miRNAs with special emphasis on HBV and HCV. Further, we assess the potential of common as well as unique signatures that may be useful in developing novel biomarkers and therapeutics.

Genome-Wide Expression of MicroRNAs Is Regulated by DNA Methylation in Hepatocarcinogenesis

Background. Previous studies, including ours, have examined the regulation of microRNAs (miRNAs) by DNA methylation, but whether this regulation occurs at a genome-wide level in hepatocellular carcinoma (HCC) is unclear. Subjects/Methods. Using a two-phase study design, we conducted genome-wide screening for DNA methylation and miRNA expression to explore the potential role of methylation alterations in miRNAs regulation. Results. We found that expressions of 25 miRNAs were statistically significantly different between tumor and nontumor tissues and perfectly differentiated HCC tumor from nontumor. Six miRNAs were overexpressed, and 19 were repressed in tumors. Among 133 miRNAs with inverse correlations between methylation and expression, 8 miRNAs (6%) showed statistically significant differences in expression between tumor and nontumor tissues. Six miRNAs were validated in 56 additional paired HCC tissues, and significant inverse correlations were observed for miR-125b and miR-199a, which is consistent with the inactive chromatin pattern found in HepG2 cells. Conclusion. These data suggest that the expressions of miR-125b and miR-199a are dramatically regulated by DNA hypermethylation that plays a key role in hepatocarcinogenesis.

Role of Sex Hormones in the Development and Progression of Hepatitis B Virus-Associated Hepatocellular Carcinoma

Infection with hepatitis B virus (HBV) is a major risk factor for hepatocellular carcinoma (HCC) in developed countries. Epidemiological reports indicate that the incidence of HBV-related HCC is higher in males and postmenopausal females than other females. Increasing evidence suggests that sex hormones such as androgens and estrogens play an important role in the progression of an HBV infection and in the development of HBV-related HCC. While androgen is supposed to stimulate the androgen signaling pathway and cooperate to the increased transcription and replication of HBV genes, estrogen may play a protecting role against the progression of HBV infections and in the development of HBV-related HCC through decreasing HBV RNA transcription and inflammatory cytokines levels. Additionally, sex hormones can also affect HBV-related hepatocarcinogenesis by inducing epigenetic changes such as the regulation of mRNA levels by microRNAs (miRNAs), DNA methylation, and histone modification in liver tissue. This review describes the molecular mechanisms underlying the gender disparity in HBV-related HCC with the aim of improving the understanding of key factors underneath the sex disparity often observed in HBV infections. Furthermore, the review will propose more effective prevention strategies and treatments of HBV-derived diseases.

Progresses in research of miR-148a in digestive system cancers

MicroRNAs (miRNAs) are a class of small non-protein-coding RNAs, which are often aberrantly expressed in the progression of various malignant tumors. Digestive system cancers are major causes of death all over the world. The finding of miRNAs provides a new direction for the diagnosis and therapy of digestive system cancers. Recent studies have demonstrated that miR-148a is aberrantly down-regulated in various digestive system cancers, including gastric cancer, hepatocellular cancer, pancreatic cancer and colorectal cancer. MiR-148a play a crucial role in the progression of these tumors as a tumor suppressor gene. This article will review the progress in research of miR-148a in digestive system cancers.

Obesity-associated mechanisms of hepatocarcinogenesis

Obesity has been recognized as a key component of the metabolic syndrome, a cluster of risk factors associated with diabetes and cardiovascular morbidity. In addition, obesity has been linked to higher frequency of cancers in a variety of tissues including the liver. Liver cancer most often occurs as hepatocellular carcinoma (HCC) complicating cirrhosis due to chronic viral infection or toxic injury and remains the third leading cause of cancer death in the world. However, HCC is increasingly diagnosed among individuals with obesity and related disorders. As these metabolic conditions have become globally prevalent, they coexist with well-established risk factors of HCC and create a unique challenge for the liver as a chronically diseased organ. Obesity-associated HCC has recently been attributed to molecular mechanisms such as chronic inflammation due to adipose tissue remodeling and pro-inflammatory adipokine secretion, ectopic lipid accumulation and lipotoxicity, altered gut microbiota, and disrupted senescence in stellate cells, as well as insulin resistance leading to increased levels of insulin and insulin-like growth factors. These mechanisms synergize with those occurring in chronic liver disease resulting from other etiologies and accelerate the development of HCC before or after the onset of cirrhosis. Increasingly common interactions between oncogenic pathways linked to obesity and chronic liver disease may explain why HCC is one of the few malignancies with rising incidence in developed countries. Better understanding of this complex process will improve our strategies of cancer prevention, prediction, and surveillance.

Hepatocellular carcinoma: clinical frontiers and perspectives

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-related death and is currently the main event leading to death in patients with cirrhosis. Evolving information suggests that the metabolic syndrome with non-alcoholic liver disease may be an important cause of HCC in addition to viral hepatitis and alcohol-induced liver disease. The molecular pathogenesis is extremely complex and heterogeneous. To date the molecular information has not impacted on treatment decisions. Periodic surveillance imaging of patients with cirrhosis is widely practiced, especially because diagnostic, radiographic criteria for early-stage HCC have been defined (including nodules between 1 and 2 cm) and effective treatment is available for tumours detected at an early stage. Worldwide the approach to resection versus transplantation varies depending upon local resources, expertise and donor availability. The criteria for transplantation are discussed, and the controversial areas highlighted with evidence-based recommendations provided. Several approaches are available for intermediate stage disease, including radiofrequency ablation, transarterial chemoembolisation and radioembolisation; the rationale for these therapies is buttressed by appropriate outcome-based studies. For advanced disease, systemic therapy with sorafenib remains the option best supported by current data. Thus, while several trials have failed to improve the benefits of established therapies, studies assessing the sequential or combined application of those already known to be beneficial are needed. Also, new concepts are provided in regards to selecting and stratifying patients for second-line studies, which may help explain the failure of prior studies.

MicroRNA-148a is silenced by hypermethylation and interacts with DNA methyltransferase 1 in hepatocellular carcinogenesis

In general, microRNAs, a class of small (~21 nucleotide) non-coding RNAs, negatively regulate the expression of their target genes. Dysregulation of miRNAs is a common feature in human cancers, but this phenomenon has not been studied extensively in hepatocellular carcinoma (HCC). miR‑148a, a member of the miR-148/152 family, has been found to be downregulated in several tumor types and has been suggested to be a tumor suppressor gene; however, its function in HCC remains unclear. Herein, we describe the epigenetic regulation of miR-148a and its impact on HCC cells. We found that, due to the hypermethylation of its CpG island, miR-148a undergoes methylation-mediated silencing in HCC cell lines. Additionally, DNMT1, the DNA methyltransferase that maintains methylation patterns, is aberrantly upregulated in HCC cell lines, and its overexpression is responsible for hypermethylation of the miR-148a promoter. Intriguingly, the expression of DNMT1, which is a target of miR-148a, is inversely correlated with the expression of miR-148a in HCC cells. These results lead us to propose the existence of a negative feedback regulatory loop between miR-148a and DNMT1 in HCC. Importantly, we demonstrate that the overexpression of miR-148a significantly inhibits HCC cell proliferation and cell cycle progression. Our results suggest the existence of a novel miR-148a-DNMT1 regulatory circuit and indicate that miR-148a acts as a tumor suppressor during hepatocellular carcinogenesis. These results may provide a promising alterative strategy for the therapeutic treatment of HCC.

miR-21 targets 15-PGDH and promotes cholangiocarcinoma growth

miRNAs are a group of small, noncoding RNAs that modulate the translation of genes by binding to specific target sites in the target mRNA. This study investigated the biologic function and molecular mechanism of miR-21 in human cholangiocarcinoma. In situ hybridization analysis of human cholangiocarcinoma specimens showed increased miR-21 in cholangiocarcinoma tissue compared with the noncancerous biliary epithelium. Lentiviral transduction of miR-21 enhanced human cholangiocarcinoma cell growth and clonogenic efficiency in vitro, whereas inhibition of miR-21 decreased these parameters. Overexpression of miR-21 also promoted cholangiocarcinoma growth using an in vivo xenograft model system. The NAD(+)-linked 15-hydroxyprostaglandin dehydrogenase (15-PGDH/HPGD), a key enzyme that converts the protumorigenic prostaglandin E2 (PGE2) to its biologically inactive metabolite, was identified as a direct target of miR-21 in cholangiocarcinoma cells. In parallel, cyclooxygenase-2 (COX2) overexpression and PGE2 treatment increased miR-21 levels and enhanced miR-21 promoter activity in human cholangiocarcinoma cells.

IMPLICATIONS

Cholangiocarcinogenesis and tumor progression are regulated by a novel interplay between COX-2/PGE2 and miR-21 signaling, which converges at 15-PGDH.

Dysregulation of microRNA biosynthesis enzyme Dicer plays an important role in gastric cancer progression

BACKGROUND AND AIM

Dicer is one of the most important components in microRNA biogenesis. Although studies have revealed the aberrantly expression of Dicer in types of cancer, the results were greatly controversial. Here we aimed to study the expression of Dicer in gastric cancer (GC) and further explored the possible roles of Dicer in cancer progression.

METHODS

The alteration of Dicer-expression in GC and its clinical significance was retrospectively studied with immunohistochemical analyses on 377 cases of cancer tissues using tissue microarray (TMA). Dicer mRNA and protein levels were also examined in 8 paired of GC tissues and non-neoplastic surrounding gastric epithelium with real time RT-PCR and western blot.

RESULTS

We found that Dicer was reduced in GC tissues in both mRNA and protein levels. Moreover, down-regulation of Dicer was correlated highly with tumor differentiation (P<0.05) and lymph node invasion (P<0.05) in GC tissues, which suggested an essential role of Dicer in cancer invasion.

CONCLUSIONS

Considering that Dicer might be closely related to progression of GC, we proposed that Dicer might offer a promising target for prevention of metastatic progression in GC.

Cytochrome P450 2J2: distribution, function, regulation, genetic polymorphisms and clinical significance

Cytochrome P450 2J2 (CYP2J2) is an enzyme mainly found in human extrahepatic tissues, with predominant expression in the cardiovascular systems and lower levels in the intestine, kidney, lung, pancreas, brain, liver, etc. During the past 15 years, CYP2J2 has attracted much attention for its epoxygenase activity in arachidonic acid (AA) metabolism. It converts AA to four epoxyeicosatrienoic acids (EETs) that have various biological effects, especially in the cardiovascular systems. In recent publications, CYP2J2 is shown highly expressed in various human tumor cells, and its EET metabolites are demonstrated to implicate in the pathologic development of human cancers. CYP2J2 is also a human CYP that involved in phase I xenobiotics metabolism. Antihistamine drugs and many other compounds were identified as the substrates of CYP2J2, and studies have demonstrated that these substrates have a broad structural diversity. CYP2J2 is found not readily induced by known P450 inducers; however, its expression could be regulated in some pathological conditions, might through the activator protein-1(AP-1), the AP-1-like element and microRNA let-7b. Several genetic mutations in the CYP2J2 gene have been identified in humans, and some of them have been shown to have potential associations with some diseases. With the increasing awareness of its roles in cancer disease and drug metabolism, studies about CYP2J2 are still going on, and various inhibitors of CYP2J2 have been determined. Further studies are needed to delineate the roles of CYP2J2 in disease pathology, drug development and clinical practice.

The Emerging Role of MicroRNAs in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is common malignancy and a leading cause of cancer death worldwide. Recent epidemiological data have demonstrated that liver cancer incidence is continuously rising and will continue to do so for more than a decade, not only South Africa and Mainland China but also in North America and Europe. Molecular profiling of changes in gene expression has improved our understanding of the HCC mechanism. MicroRNAs (miRNAs) are a class of small regulatory RNAs that function to modulate protein expression. This control allows for fine-tuning of the cellular phenotype, including regulation of proliferation, cell signaling and apoptosis. Recently, investigators have demonstrated decreased or increased expression of particular miRNAs in hepatobiliary cancer cells. Many studies have highlighted the role of miRNA in physiological processes and cancer development. Several studies have reported that some miRNAs may play a role in the development and progression of HCC. Recent investigations have suggested that the presence of single nucleotide polymorphisms in miRNA genes, their processing machinery and target binding sites affect cancer risk, treatment efficacy and patient prognosis. This review will discuss the emerging critical role of miRNAs in hepatocarcinogenesis, HCC progression and clinical outcome.

How to cite this article: Akkiz H. The Emerging Role of MicroRNAs in Hepatocellular Carcinoma. Euroasian J Hepato-Gastroenterol 2014;4(1):45-50.

Current status of miRNA-targeting therapeutics and preclinical studies against gastroenterological carcinoma

Expanding knowledge about the crucial roles of microRNAs (miRNAs) in human diseases has led to the idea that miRNAs may be novel, promising therapeutic targets against various pathological conditions. The recent success of a human clinical trial using anti-miR-122 oligonucleotides against chronic hepatitis C virus has paved the way for this approach. In this review, we summarize briefly the current status of clinical trials of miRNA-targeting therapy and several representative preclinical trials against hepato-gastrointestinal carcinoma. In addition, we describe the currently available technologies for modification and delivery of oligonucleotides, which are essential in providing efficient, specific and safe approaches to targeting miRNAs.

Current status of miRNA-targeting therapeutics and preclinical studies against gastroenterological carcinoma

Expanding knowledge about the crucial roles of microRNAs (miRNAs) in human diseases has led to the idea that miRNAs may be novel, promising therapeutic targets against various pathological conditions. The recent success of a human clinical trial using anti-miR-122 oligonucleotides against chronic hepatitis C virus has paved the way for this approach. In this review, we summarize briefly the current status of clinical trials of miRNA-targeting therapy and several representative preclinical trials against hepato-gastrointestinal carcinoma. In addition, we describe the currently available technologies for modification and delivery of oligonucleotides, which are essential in providing efficient, specific and safe approaches to targeting miRNAs.

MicroRNA-196A-2 polymorphisms and hepatocellular carcinoma in patients with chronic hepatitis B

Single nucleotide polymorphisms (SNPs) in microRNA (miR)-196a-2 have been suggested to contribute to susceptibility to various human cancers. The aim of this study was to determine whether polymorphisms of miRNA-196a-2 affect the clinical outcomes of hepatitis B virus (HBV) infection in Korean patients. Genotyping was performed for 1,439 Korean patients with either past or present HBV infection, including 404 control subjects who underwent spontaneous recovery and 1,035 subjects with chronic HBV (313 cases of chronic hepatitis B, 305 cases of cirrhosis of the liver, and 417 cases of hepatocellular carcinoma [HCC]). Genotyping results revealed that the polymorphism rs12304647A>C, which lies in the pri-miRNA region of miR-196a-2, has a significant minor allele frequency (0.210). Logistic analysis revealed that the rs12304647A>C SNP was associated with a significant protective effect against HCC in patients with chronic hepatitis (odds ratio [OR] = 0.70, P = 0.005 in a codominant model; OR = 0.73, P = 0.03 in a dominant model; OR = 0.31, P = 0.004 in a recessive model), and in the patients with cirrhosis (OR = 0.63, P = 0.0009 in a codominant model; OR = 0.66, P = 0.01 in a dominant model; OR = 0.25, P = 0.001 in a recessive model). A Cox relative hazards model with adjustments for age, gender, HBeAg status, and cirrhosis revealed that rs12304647A>C retained its association with HCC in a codominant model (relative hazards [RH] = 1.14, P = 0.05) and in a recessive model (RH = 1.44, P = 0.03). However, the miR-196a-2 rs12304647A>C SNP had no association with HBV clearance. In conclusion, the miR-196a-2 rs12304647 CC genotype had a protective effect against development of HCC in comparison to the AA or AC genotypes in patients with chronic hepatitis and cirrhosis.

Circulating microRNA-101 as a potential biomarker for hepatitis B virus-related hepatocellular carcinoma

Circulating microRNAs (miRNAs) are emerging as promising biomarkers for cancer; however, the significance of circulating miRNAs in hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC) remains largely unknown. Based on our prior observations that miRNA-101 (miR-101) is downregulated by HBV and induces epigenetic modification, we sought to test whether circulating miR-101 may serve as a potential biomarker for HCC. The expression of miR-101 in HCCs and serum was evaluated by real-time polymerase chain reaction. Tissue and serum miR-101 levels were assessed in samples from patients with HBV-related HCC and healthy controls. A potential correlation was also evaluated between miR-101 expression and the clinicopathological features and prognosis of HCC patients. miR-101 was downregulated in HBV-related HCC tissues compared with adjacent noncancerous tissues. Furthermore, the miR-101 levels in these tissues from HCC patients were significantly lower than those in tissues from control subjects. Notably, serum miR-101 levels were found to have an inverse correlation with tissue miR-101 expression levels. The expression of serum miR-101 in patients with HBV-related HCC was significantly higher than that in the healthy controls, and this increase correlated with hepatitis B surface antigen positivity, HBV DNA levels and tumor size. These results indicate that different factors govern the levels of miR-101 in the tissue and serum of HCC patients. Given the marked and consistent increase in serum miR-101 levels in HCC patients, circulating miR-101 may serve as a promising biochemical marker for monitoring the progression of tumor development in HBV-related HCC.

Exploration of genome-wide circulating microRNA in hepatocellular carcinoma: MiR-483-5p as a potential biomarker

BACKGROUND

MicroRNAs (miRNA) are abundant in the circulation and play a central role in diverse biologic processes; they may be useful for early diagnosis of hepatocellular carcinoma.

METHODS

We conducted a two-phase, case-control study (20 pairs for the discovery set and 49 pairs for the validation set) to test the hypothesis that genome-wide dysregulation of circulating miRNAs differentiates hepatocellular carcinoma cases from controls. Taqman low-density arrays were used to examine genome-wide miRNA expression for the discovery set, and quantitative real-time PCR was used to validate candidate miRNAs for both discovery and validation sets.

RESULTS

Sixty-six miRNAs were found to be significantly overexpressed in plasma of hepatocellular carcinoma cases compared with controls after adjusting for false discovery rate (P < 0.05). A volcano plot indicated that seven miRNAs had greater than 2-fold case-control differences with P < 0.01. Four significant miRNAs (miR-150, miR-30c, miR-483-5p, and miR-520b) detectable in all samples with varied expression levels were further validated in a validation set. MiR-483-5p was statistically significantly overexpressed in hepatocellular carcinoma cases compared with controls (3.20 vs. 0.82, P < 0.0001). Hepatocellular carcinoma risk factors and clinic-pathological characteristics did not influence miR-483-5p expression. The combination of plasma miR-483-5p level and hepatitis C virus status can significantly differentiate hepatocellular carcinoma cases from controls with an area under the curve of 0.908 (P < 0.0001). The sensitivity and specificity were, respectively, 75.5% and 89.8%.

CONCLUSIONS

These preliminary results suggest the importance of dysregulated circulating miR-483-5p as a potential hepatocellular carcinoma biomarker.

IMPACT

Confirmation of aberrant expression of miR-483-5p in a large prospective hepatocellular carcinoma study will provide support for its application to hepatocellular carcinoma detection.

A potentially functional polymorphism in the promoter region of let-7 family is associated with survival of hepatocellular carcinoma

BACKGROUND

The let-7 family plays a vital role in the normal cellular activity of liver cells and the carcinogenesis of hepatocellular carcinoma (HCC). In the previous study, we have detected the association between single nucleotide polymorphisms (SNPs) in the promoter region of let-7 and susceptibility to HCC. However, it is still unknown whether these polymorphisms are associated with HCC prognosis.

METHODS

We investigated the effect of two potentially functional SNPs in the promoter region of let-7 family, rs10877887 (T>C) and rs13293512 (T>C), on the overall survival of 331 HCC patients. Log-rank test and Cox proportional hazard models were used for the survival analyses.

RESULTS

We found that HCC patients carrying the C allele of rs10877887 had a significantly increased death risk (adjusted HR=1.22, 95%CI=1.02-1.47, P=0.03 in the additive model), compared to those with T allele. In the stratified analysis, the risk effect was evident in HCC patients with Barcelona Clinic Liver Cancer (BCLC) stage B (adjusted HR=1.24, 95%CI=1.02-1.51, P=0.03) and in those who received chemotherapy or intervention (adjusted HR=1.25, 95%CI=1.02-1.53, P=0.04).

CONCLUSIONS

Our results suggest that rs10877887 in the promoter region of let-7 may be a prognostic biomarker for HCC patients, which need the validation from other larger studies in different populations.

Identification of cancer stem cells from hepatocellular carcinoma cell lines and their related microRNAs

The aim of this study was to identify cancer stem cells (CSC) from three hepatocellular carcinoma (HCC) cell lines and to screen for specific microRNAs (miRNAs) regulating CSCs. Side population (SP) phenotype analysis was used. Four factors in the staining process, the incubation time, shaking interval, culture time and Hoechst 33342 concentration were explored, respectively, to define the SP subtype. CSC characteristics of SP cells were verified by sphere-forming assay and tumorigenic ability in NOD/SCID mice. QPCR assay for 370 miRNAs was performed to identify the differential miRNA expression between SP and Non-SP (NSP) cells in the PLC/PRF/5 cell line. The selected miRNAs were tested again in SP and NSP cells from Huh-7 and Hep-3B cell lines by qPCR assay. All four factors influenced SP percentage, when the other three conditions were fixed, the optimal Hoechst 33342 concentrations determined were 11 µg/ml for PLC/PRF/5 cells, 4 µg/ml for Huh-7 and 5 µg/ml for Hep-3B cells. The resultant SP percentage was 0.73±0.12%, 0.49±0.04% and 0.63±0.08%, respectively. The purity of sorted SP cells was >85%. Floating spheres were formed by SP cells from all three cell lines, while NSP cells did not form a single floating sphere. Mice injected with SP cells on the right side formed more tumor masses compared to their counterpart NSP at the same injection dosage; qPCR profiling identified 27 differentially expressed miRNAs in PLC/PRF/5 cells. Subsequent qPCR assay showed that miR-9* and miR-194 were also downregulated in SP cells from Huh-7 and Hep-3B. The present study identified CSCs via SP and sphere-forming assay from three liver cancer cell lines. Altogether, 27 CSC-specific miRNAs were determined in PLC/PRF/5; miR-9* and miR-194 were identified as the common CSC-specific miRNAs across the three HCC cell lines.

MicroRNA-22 expression in hepatocellular carcinoma and its correlation with ezrin protein

Objective

Expression of microRNA-22 (miR-22) and ezrin protein (a membrane–cytoskeleton linking protein) in hepatocellular carcinoma (HCC) was investigated.

Methods

Specimens of HCC and paracancerous tissue (control; ∼5 cm away from tumour tissue) were collected from 192 patients. miR-22 expression was detected by real-time polymerase chain reaction; ezrin protein expression in tumour tissue was assessed immunohistochemically. Associations between miR-22 expression and clinicopathological features of HCC and ezrin expression were analysed.

Results

miR-22 expression was lower in HCC tissue than in paracancerous tissue samples (median relative expression 0.676 versus 1.000 for control tissue). Expression of miR-22 was significantly associated with histological differentiation (relative expression 0.431 for lower grades of differentiation versus 0.918 for higher grades), and was associated with lymphatic metastasis (relative expression 0.518 if metastasis was present, 0.919 if absent). Survival time was shorter in patients with low miR-22 expression than in those with high expression (31.0 ± 2.6 versus 52.2 ± 5.1 months). There was a significant negative correlation between the expression of miR-22 and that of ezrin.

Conclusions

miR-22 is downregulated in HCC and its expression is associated with the differentiation, metastasis and prognosis of the carcinoma. Ezrin is a potential regulatory protein of miR-22.