Competing Endogenous RNAs in Hepatocellular Carcinoma-The Pinnacle of Rivalry

The role of noncoding transcripts in gene expression is nowadays acknowledged to keep various diseases at bay-despite being referred to as "junk" DNA several years ago. Believed to be at the heart of multiple regulatory pathways, microRNAs (miRNAs) are small noncoding RNAs (ncRNAs) involved in posttranscriptional gene regulation. Recently, the discovery of ncRNAs that compete for shared miRNA pools has dimmed the light on the solo performance of miRNAs in genomic regulation. Indeed, several studies describe RNAs such as long noncoding RNAs, mRNAs, circular RNAs, pseudogenes, and viral RNAs as competing endogenous RNAs (ceRNAs) that sequester miRNAs, allowing for de-repression of downstream miRNA targets. Such integration between coding and noncoding transcripts forms complex ceRNA networks that when dysregulated lead to several diseases such as hepatocellular carcinoma. Here, the authors review perturbed ceRNA networks in hepatocellular carcinoma, describe the role of each in tumorigenesis, and discuss their various clinical implications.

Epigallocatechin gallate (EGCG) and miR-548m reduce HCV entry through repression of CD81 receptor in HCV cell models

Epigallocatechin gallate (EGCG) is the most abundant component in green tea extract, that has powerful antioxidant and antiviral effects. It has been previously reported to inhibit HCV entry via several mechanisms. Hence, this study aimed at further investigating the potential impact of EGCG on HCV entry through regulation of the expression of tetraspanin receptor CD81 by the novel predicted miR-548m. Liver biopsies were obtained from 29 HCV patients and 10 healthy controls for expression profiling. Huh7 cells were stimulated with EGCG and subsequently miR-548m expression was assessed. Naïve, HCV- ED43/JFH-1 and HCV-JFH-1 infected Huh7 cells were transfected by miR-548m mimics and inhibitors. Consequently, CD81 protein and mRNA levels were assessed using flow cytometry and qRT-PCR, respectively. Additionally, these cells were used to investigate HCV permissiveness into Huh7 cells using qRT-PCR for viral quantification. Direct binding confirmation of miR-548m to CD81 was done using luciferase reporter assay. In-silico analysis revealed miR-548m to have two potential binding sites in the 3'UTR of CD81 mRNA. EGCG boosted miR-548m expression in Huh7 cells. Additionally, miR-548m caused a downregulation of CD81 protein and mRNA levels as well as reduction in HCV infectivity of Huh7 cells. Luciferase binding assay confirmed the binding of miR-548m to CD81 mRNA at the two predicted binding sites. Intriguingly, miR-548m expression was not detected in healthy liver biopsies but was found in liver biopsies of HCV patients. This study shows that EGCG might act as an anti-HCV agent that reduces cellular infectivity via enhancing miR-548m expression and repressing CD81 receptor.

Reduction of CD19 autoimmunity marker on B cells of paediatric SLE patients through repressing PU.1/TNF-α/BAFF axis pathway by miR-155

microRNA-155 (miR-155) is implicated in regulating B-cell activation and survival that is important in systemic lupus erythematosus (SLE) pathogenesis. PU.1, a target for miR-155, is a crucial regulator of B-cell development and enhances Tumour-Necrosis-factor-alpha (TNF-α) expression. TNF-α induces the expression of B-cell-activating-factor (BAFF). BAFF is reported to increase the expression of the autoimmunity marker; CD19. This study aimed to investigate the regulation of expression of PU.1 in pediatric-systemic-lupus-erythematosus (pSLE) patients by miR-155, and hence evaluate its impact on TNF-α/BAFF/CD19 signalling pathway. Screening revealed that PU.1 is upregulated in PBMCs and B-cells of pSLE patients. PU.1 expression directly correlated with systemic-lupus-erythematosus disease-activity-index-2 K SLEDAI-2K. Ectopic expression of miR-155 and knockdown of PU.1 suppressed PU.1, TNF-α and BAFF. Finally, miR-155 decreased the proportion of BAFF-expressing-B-cells and CD19 protein expression. These findings suggest that miR-155 suppresses autoimmunity through transcriptional repression of PU.1 and TNF-α, which in turn suppresses BAFF and CD19 protein expression.

MiR-615-5p depresses natural killer cells cytotoxicity through repressing IGF-1R in hepatocellular carcinoma patients

miR-615-5p was characterized by our group as a tumour suppressor. IGF-1 R activates a downstream signalling pathway, well characterized in liver cells, however, its role in immunity especially Natural Killer cells (NKs) remains vague. This study aimed at investigating the regulatory role of miR-615-5p on IGF signalling and its impact on NKs cytotoxicity in HCC. Our results showed an upregulation in miR-615-5p and IGF-1 R in NKs of 130 HCC patients compared to 35 controls. Forcing the expression of miR-615-5p, repressed IGF-IR, attenuated NKs cytotoxicity, decreased CD56^dim, increased CD56^bright NK subsets and reduced the cytotoxic markers NKG2D, TNF-α and perforins. It repressed NKG2D ligand (ULBP2) in Huh-7 cells. In conclusion, miR-615-5p represses IGF-1 R in NKs and their target hepatocytes; however, it has a contradicting impact on HCC progression on both cell types. These findings might pave the way for better understanding the role of microRNAs in NKs function and HCC immune-pathogenesis.

miR-29a Promotes Lipid Droplet and Triglyceride Formation in HCV Infection by Inducing Expression of SREBP-1c and CAV1

Aims: To examine the regulation of SREBP-1c and CAV1 by microRNA-29a (miR-29a) in cells infected with hepatitis C virus (HCV) in an attempt to control HCV-induced non-alcoholic fatty liver disease. Methods: In order to examine the manipulation of SREBP-1c and CAV1 by miR-29a, oleic acid (OA)-treated JFH-I-infected Huh-7 cells were used. OA was added 24 h post-transfection and gene expression was investigated by qRT-PCR at 48 h post treatment. The functional impact of the observed alteration in SREBP-1c and CAV1 expression was analyzed by examining lipid droplet (LD) and triglyceride (TG) content at 72 h post-OA treatment using light microscopy and spectrophotometry, respectively. Viral load was quantified by qRT-PCR at 72 h post-transfection. Results: OA treatment induced the expression of miR-29a and SREBP-1c, as compared to untreated cells. Forced miR-29a expression led to a significant up-regulation of SREBP-1c as well as CAV1 compared to mock untransfected cells. Ectopic expression of miR-29a resulted in a marked increase in LDs and their respective TGs, while miR-29a antagomirs decreased both the LD and TG content compared to mock untransfected cells. Moreover, forcing the expression of miR-29a in JFH-1 HCV-infected Huh-7 cells resulted in 53% reduction in viral titers compared to mock untransfected Huh-7 cells. Conclusion: Inducing miR-29a expression significantly induces SREBP-1c and CAV1 expression, thereby increasing LDs as well as their respective TGs. Nonetheless, forcing the expression of miR-29a resulted in reduction of HCV RNA levels in Huh-7 cells.

miR-34a: Multiple Opposing Targets and One Destiny in Hepatocellular Carcinoma

Background and Aims: The role of miR-34a in hepatocellular carcinoma (HCC) is controversial and several unresolved issues remain, including its expression pattern and relevance to tumor etiology, tumor stage and prognosis, and finally, its impact on apoptosis. Methods: miR-34a expression was assessed in hepatitis C virus (HCV)-induced non-metastatic HCC tissues by RT-Q-PCR. Huh-7 cells were transfected with miR-34a mimics and the impact of miR-34a was examined on 84 pro-apoptotic/anti-apoptotic genes using PCR array; its net effect was tested on cell viability via MTT assay. Results: miR-34a expression was up-regulated in HCC tissues. Moreover, miR-34a induced a large set of pro-apoptotic/anti-apoptotic genes, with a net result of triggering apoptosis and repressing cell viability. Conclusions: HCC-related differential expression of miR-34a could be etiology-based or stage-specific, and low expression of miR-34a may predict poor prognosis. This study's findings also emphasize the role of miR-34a in apoptosis.

Interplay between microRNA-17-5p, insulin-like growth factor-II through binding protein-3 in hepatocellular carcinoma

AIM: To investigate the effect of microRNA on insulin-like growth factor binding protein-3 (IGFBP-3) and hence on insulin-like growth factor-II (IGF-II) bioavailability in hepatocellular carcinoma (HCC).

METHODS: Bioinformatic analysis was performed using microrna.org, DIANA lab and Segal lab softwares. Total RNA was extracted from 23 HCC and 10 healthy liver tissues using mirVana miRNA Isolation Kit. microRNA-17-5p (miR-17-5p) expression was mimicked and antagonized in HuH-7 cell lines using HiPerFect Transfection Reagent, then total RNA was extracted using Biozol reagent then reverse transcribed into cDNA followed by quantification of miR-17-5p and IGFBP-3 expression using TaqMan real-time quantitative PCR. Luciferase reporter assay was performed to validate the binding of miR-17-5p to the 3’UTR of IGFBP-3. Free IGF-II protein was measured in transfected HuH-7 cells using IGF-II ELISA kit.

RESULTS: Bioinformatic analysis revealed IGFBP-3 as a potential target for miR-17-5p. Screening of miR-17-5p and IGFBP-3 revealed a moderate negative correlation in HCC patients, where miR-17-5p was extensively underexpressed in HCC tissues (P = 0.0012), while IGFBP-3 showed significant upregulation in the same set of patients (P = 0.0041) compared to healthy donors. Forcing miR-17-5p expression in HuH-7 cell lines showed a significant downregulation of IGFBP-3 mRNA expression (P = 0.0267) and a significant increase in free IGF-II protein (P = 0.0339) compared to mock untransfected cells using unpaired t-test. Luciferase assay validated IGFBP-3 as a direct target of miR-17-5p; luciferase activity was inhibited by 27.5% in cells co-transfected with miR-17-5p mimics and the construct harboring the wild-type binding region 2 of IGFBP-3 compared to cells transfected with this construct alone (P = 0.0474).

CONCLUSION: These data suggest that regulating IGF-II bioavailability and hence HCC progression can be achieved through targeting IGFBP-3 via manipulating the expression of miRNAs.

Contradicting interplay between insulin-like growth factor-1 and miR-486-5p in primary NK cells and hepatoma cell lines with a contemporary inhibitory impact on HCC tumor progression

In this study, an impaired natural killer (NK) cell cytolytic activity in 135 hepatocellular carcinoma (HCC) patients parallel to a reduced expression level of insulin-like growth factor (IGF)-1 in NK cells of HCC patients has been revealed. Ectopic expression of miR-486-5p, a direct upstream regulator of IGF-1, restored the endogenous level of IGF-1 in NK cells of HCC patients, thus augmenting its cytolytic activity against Huh7 cells in an opposite manner to the IGF-1 siRNAs. Unorthodoxly, over-expression of miR-486-5p in target hepatocytes resulted in the repression of IGF-1, suppression of Huh7 cells proliferation and viability in a similar pattern to the IGF-1 siRNAs. Therefore, this study highlights a potential role of IGF-1 in modulating cytolytic potential of NK cells of HCC patients. miR-486-5p acts in a cell-specific manner, differentially modulating IGF-1 expression in NK cells and their target hepatocytes with a contemporary inhibitory impact on HCC progression.

MicroRNA-486-5p enhances hepatocellular carcinoma tumor suppression through repression of IGF-1R and its downstream mTOR, STAT3 and c-Myc

The insulin-like growth factor (IGF)-axis has been paradigmatically involved in hepatocellular carcinoma (HCC) tumor initiation, progression and drug resistance. Consequently, members of the IGF-axis and most importantly, IGF-1 receptor (IGF-1R) have been considered as intriguing targets for HCC therapy. Few miRNAs have been recently reported to be associated with IGF-1R regulation. The present study aimed to investigate the role of microRNA (miRNA/miR)-486-5p in the regulation of IGF-1R and its downstream signaling cascades. miR-486-5p was markedly downregulated in hepatitis C virus-induced HCC tissues and Huh-7 cells. Forcing the expression of miR-486-5p in Huh-7 cells resulted in the repression of IGF-1R, mammalian target of rapamycin (mTOR), signal transducer and activator of transcription 3 (STAT3) and c-Myc mRNA levels. Ectopic expression of miR-486-5p in Huh-7 cells markedly repressed cellular viability, proliferation, migration and clonogenicity in a similar pattern to IGF-1R small interfering RNAs, and were evaluated using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, BrdU incorporation, wound healing and colony forming assays, respectively. Overall, the study findings demonstrated that miR-486-5p acts as a tumor suppressor in HCC through the repression of essential members of the IGF-axis, including IGF-1R and its downstream mediators mTOR, STAT3 and c-Myc.

Epigenetic regulation of insulin-like growth factor axis in hepatocellular carcinoma

The insulin-like growth factor (IGF) signaling pathway is an important pathway in the process of hepatocarcinogenesis, and the IGF network is clearly dysregulated in many cancers and developmental abnormalities. In hepatocellular carcinoma (HCC), only a minority of patients are eligible for curative treatments, such as tumor resection or liver transplant. Unfortunately, there is a high recurrence of HCC after surgical tumor removal. Recent research efforts have focused on targeting IGF axis members in an attempt to find therapeutic options for many health problems. In this review, we shed lights on the regulation of members of the IGF axis, mainly by microRNAs in HCC. MicroRNAs in HCC attempt to halt the aberrant expression of the IGF network, and a single microRNA can have multiple downstream targets in one or more signaling pathways. Targeting microRNAs is a relatively new approach for identifying an efficient radical cure for HCC.

Abrogating the interplay between IGF2BP1, 2 and 3 and IGF1R by let-7i arrests hepatocellular carcinoma growth

IGF2BP 1, 2 and 3 control the fate of many transcripts. Immunoprecipitation studies demonstrated the IGF2BPs to bind to IGF1R mRNA, and our laboratory has recently shown them to post-transcriptionally regulate IGF1R. This study sought to identify a microRNA regulating the IGF2BPs and consequently IGF1R. All three IGF2BPs were among the top-ranked predicted targets of let-7i. Let-7i was downregulated in HCC tissues, and transfection of HuH-7 with let-7i inhibited malignant cell behaviors and decreased IGF2BPs transcripts. Direct binding of let-7i to IGF2BP2 and IGF2BP3 3'UTRs was confirmed, and the effect of let-7i caused a decrease in the IGF2BPs' target gene, the IGF1R. IGF1R mRNA was inversely correlated with let-7i in HCC tissues and was reduced upon let-7i transfection into HuH-7. Reporter assays validated IGF1R as a target of let-7i. Therefore, let-7i may control HCC tumorigenesis by regulating IGF1R directly and indirectly by interrupting the interplay between IGF1R and the IGF2BPs.

Repressing PU.1 by miR-29a∗ in NK cells of HCV patients, diminishes its cytolytic effect on HCV infected cell models

OBJECTIVES

Natural killer cells are immune safeguards against HCV infection. PU.1 is a pivotal transcription factor in the development of NK cells. This study aimed at studying the regulatory effect of miRNAs on both development and function of NK cells isolated from HCV patients.

METHODS

NK cells were isolated from 17 chronic HCV patients and 12 healthy controls; after which miRNA and mRNA were quantified using qRT-PCR. Manipulating miRNA expression using mimics and antagomirs, was performed followed by investigating downstream targets as well as viral abundance.

RESULTS

PU.1 expression levels were upregulated in NK cells of HCV patients. In silico analysis revealed PU.1 to be a potential downstream target of miR-29a(∗), where miR-29a(∗) overexpression in NK cells caused a significant downregulation in PU.1 mRNA. Forcing miR-29a(∗) caused a downregulation of the cytotoxicity determinant NK activating receptor (NKG2D) via upregulation of miR-155. Moreover, perforin-1 mRNA was found to be downregulated upon forcing the expression of miR-29a(∗) in NK cells of HCV patients. This decrease in NK cytolytic function was accompanied by an 80% viral load increase in cocultured HCVcc cell models.

CONCLUSIONS

This study showed that HCV infection might abrogate NK cytotoxic potential through altering PU.1, NKG2D receptor and perforin molecules.

Targeting E2F1 and c-Myc expression by microRNA-17-5p represses interferon-stimulated gene MxA in peripheral blood mononuclear cells of pediatric systemic lupus erythematosus patients

OBJECTIVES

Elevated type I interferon (IFN) is believed to be one of the crucial factors involved in the pathogenesis of systemic lupus erythematosus (SLE). Its expression was recently found to be governed by the transcription factor E2F1 which is involved in an autoregulatory triad along with c-Myc and the microRNA polycistron miR-17-92. However, this intricate triad has seldom been investigated in SLE patients. Therefore, the current study was undertaken to investigate the expression pattern of the E2F1/c-Myc/miR-17-5p triad in peripheral blood of SLE patients as well as to examine the impact of manipulating this triad using miR-17-5p mimics and inhibitors on IFN signature in SLE patients.

METHODS

Expression of the E2F1/c-Myc/miR-17-5p triad and the IFN-stimulated gene MxA was analyzed using real time qPCR. Peripheral blood mononuclear cells from SLE patients and controls were transfected with miR-17-5p mimics and antagomirs using the HiPerfect transfection reagent.

RESULTS

E2F1 transcripts and miR-17-5p were significantly downregulated while c-Myc and MxA transcripts were significantly upregulated in SLE. Also, transfection of SLE PBMCs with miR-17-5p mimics led to a substantial repression of E2F1 and c-Myc expression. The overall change in this triad upon miR-17-5p mimicking resulted in lowering the transcript levels of the IFN-inducible gene MxA in SLE.

CONCLUSION

This may advocate the manipulation/use of the E2F1/c-Myc/miR-17-5p trinity to effectively control the aberrantly high levels of type I IFN activity in lupus patients.

A pleiotropic effect of the single clustered hepatic metastamiRs miR-96-5p and miR-182-5p on insulin-like growth factor II, insulin-like growth factor-1 receptor and insulin-like growth factor-binding protein-3 in hepatocellular carcinoma

MicroRNAs (miRs) have a major role in the pathogenesis of hepatocellular carcinoma (HCC). As the insulin-like growth factor (IGF) axis is a highly tumorigenic pathway in HCC, the present study attempted to target it with miRs. Potential targeting of crucial members of the IGF axis by miRNAs at the 3'-untranslated region (3'-UTR) was predicted using bioinformatic tools, such as microrna.org, Diana lab and Targetscan, while 5'-UTR targeting was predicted using bibiserv software. Expression profiling of obtained miRNAs was performed using quantitative polymerase chain reaction (qPCR) in 22 non-metastatic HCC biopsy samples and 10 healthy tissues. To investigate the impact of miRNAs on their potential downstream targets, transfection of miRNAs was performed in HuH-7 cells and the targets' expression was quantified using qPCR. Transcripts of insulin-like growth factor-1 receptor (IGF-1R), insulin-like growth factor binding protein-3 (IGFBP-3) and IGF-II were found to be potentially targeted at the 5'-UTR and 3'-UTR regions by the single clustered hepatic metastamiRs miR-96-5p and miR-182-5p. The two miRNAs showed a similar expression pattern in HCC tissues compared to those in healthy tissues. Forced expression of miR-96-5p and miR-182-5p in the HCC cell line HuH-7 had inducing effects on IGFBP-3 and IGF-II transcripts. Of note, the two miRs had differential effects on IGF-1R, where miR-96-5p induced IGF-1R mRNA expression and miR-182-5p inhibited its expression. The present study revealed the pleiotropic impact of the single clustered hepatic metastamiRs miR-96-5p and miR-182-5p on IGF-1R, and an inducing effect on IGF-II and IGFBP-3 in hepatocellular carcinoma.

Expression signature of microRNA-155 in hepatitis C virus genotype 4 infection

Hepatits C virus (HCV) genotype 4 (GT4) shows low treatment response rates and discrepancies when compared to other genotypes. However, the reason underlying these discrepancies remains unclear due to the limited number of studies on GT4. microRNA-155 (miR-155) is a noteworthy example of a discrepancy in GT4, as it was found to be upregulated in genotypes 1, 2 and 3 HCV infection, but downregulated in GT4-HCV-infected peripheral blood mononuclear cells (PBMCs). The present study aimed to investigate the expression of miR-155 in PBMCs, serum and liver tissues of GT4-HCV-infected patients. miR-155 expression was assessed using reverse transcription-quantitative polymerase chain reaction in GT4-HCV-infected PBMCs, serum and liver tissues, as well as GT2- and GT4-infected Huh7 cells, and compared to the healthy controls. There was no difference in miR-155 expression observed between naïve GT4-HCV patients and healthy controls in the PBMCs and serum. In HCV-infected liver tissues, however, a significant downregulation was observed. The unique miR-155 expression pattern during GT4 infection was confirmed in the infected Huh7 cell lines when compared to GT2 infection. Clinical data showed a positive correlation between liver transaminases and serum miR-155 expression. In addition, serum miR-155 expression was significantly lower in naïve non-responders (NRs) than naïve sustained virological responders (SVRs), and in post-treatment NRs compared to post-treatment SVRs. In conclusion, miR-155 was not only proven to be a genotype-specific microRNA that is not induced during GT4-HCV infection, but also a good prognostic factor and predictor of response to treatment enabling a non-invasive differentiation between NRs and SVRs during GT4-HCV infection.

Correcting the expression of miRNA-155 represses PP2Ac and enhances the release of IL-2 in PBMCs of juvenile SLE patients

MicroRNA-155 is involved in immune cell, differentiation, maturation and function. MiR-155 showed variable dysregulated expression in autoimmune diseases such as systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA) patients. MiR-155 was previously confirmed to directly target CAMP response element binding protein (CREB), which was previously identified as a positive regulator of protein phosphatase 2A (PP2A). PP2A is a key negative regulator of interleukin-2, which is an important immune modulator and was previously shown to be decreased in SLE. In this study we aimed at investigating the regulation of PP2A by miR-155 and hence its role in juvenile SLE disease pathogenesis. MiR-155 showed significant downregulation in PBMCs from juvenile SLE and juvenile familial Mediterranean fever (FMF) and significant upregulation in PBMCs from juvenile idiopathic arthritis (JIA) patients. In SLE, miR-155 expression was negatively correlated with Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) score and proteinuria and was positively correlated with white blood cell (WBC) count. The mRNA of the catalytic subunit of PP2A (PP2Ac) showed significant upregulation in PBMCs from SLE and FMF but not in JIA patients. Additionally, the relative expression of PP2Ac mRNA was positively correlated with SLEDAI score. Forced expression of miR-155 led to decreased relative expression of PP2Ac mRNA and increased IL-2 release in cultured-stimulated PBMCs. This study suggests for the first time the possible role of an miR-155-PP2Ac loop in regulating IL-2 release and identifies miR-155 as a potential therapeutic target in juvenile SLE disease through relieving IL-2 from the inhibitory role of PP2A.

Mir-194 is a hepatocyte gate keeper hindering HCV entry through targeting CD81 receptor

OBJECTIVE

The tetraspanin CD81 is one of the main receptors involved in hepatitis C virus entry. Herein, we aimed to explore the role of microRNAs in regulating CD81 receptor expression and function.

PATIENTS AND METHODS

Bioinformatics analysis was carried out to select potential mircroRNAs that binds CD81 3'untranslated region. Liver biopsies taken from 28 HCV genotype- 4 patients and 10 healthy donors were screened. Naïve, JFH1 and ED43/JFH1- infected- Huh7 cells were transfected with mimics and inhibitors followed by analyzing CD81 protein and mRNA expression. This was done using flow cytometry and Q-RT PCR, respectively. HCV entry into Huh7 cells was investigated post-transfection. Binding confirmation was done using luciferase reporter vector harboring wild/mutant target sites of microRNA. The impact of Epigallocatechin-gallate on modulating microRNA/CD81 expression was assessed.

RESULTS

Bioinformatics revealed that CD81 is a potential down-stream target for miR-194. A significant inverse correlation was found between miR-194 and CD81 expression in liver biopsies of HCV patients. Forcing the expression of miR-194 showed a down-regulation of CD81 protein, mRNA expression and significantly abrogated the HCV infectivity of Huh7 cells. Stimulation with EGCG enhanced mir-194 expression and down-regulated CD81 expression.

CONCLUSION

This study showed that mir-194 hinders HCV entry through targeting CD81 receptors.

Predictive prognostic role of miR-181a with discrepancy in the liver and serum of genotype 4 hepatitis C virus patients

microRNA (miRNA) expression in organs does not always represent their quantity in serum. A disparity in the expression of miR-181a has been reported in the tissues and serum of hepatocellular carcinoma (HCC) patients. Since hepatitis C virus (HCV) is a major cause of HCC and miR-181a has never been studied in HCV, the present study aimed to investigate the miR-181a expression profile in genotype 4 (GT4)-HCV patients to evaluate whether this pattern is also apparent in HCV. RNA was extracted from liver tissues, peripheral mononuclear cells (PBMCs) and serum samples from GT4-HCV-infected patients and healthy donors to evaluate the relative miR-181a expression using quantitative reverse transcription-polymerase chain reaction. miR-181a was significantly higher in the serum of naïve patients compared to controls, and an inverse correlation with the viral load and liver enzymes was apparent. By contrast, no difference in miR-181a expression was observed in the liver tissues and PBMCs of patients compared to controls. This expression observed in HCV is conflicting to that previously reported in HCC. The study also demonstrates a significant upregulation of miR-181a post-interferon/ribavirin treatment in the serum of sustained virological responders (SVRs) compared to non-responders and treatment-naïve SVRs. In conclusion, miR-181a may be considered to be a possible prognostic marker in GT4-HCV infection.

Repression of miR-17-5p with elevated expression of E2F-1 and c-MYC in non-metastatic hepatocellular carcinoma and enhancement of cell growth upon reversing this expression pattern

E2F-1, c-MYC, and miR-17-5p is a triad of two regulatory loops: a negative and a positive loop, where c-MYC induces the expression of E2F-1 that induces the expression of miR-17-5p which in turn reverses the expression of E2F-1 to close the loop. In this study, we investigated this triad for the first time in hepatocellular carcinoma (HCC), where miR-17-5p showed a significant down-regulation in 23 non-metastatic HCC biopsies compared to 10 healthy tissues; however, E2F-1 and c-MYC transcripts were markedly elevated. Forced over-expression of miR-17-5p in HuH-7 cells resulted in enhanced cell proliferation, growth, migration and clonogenicity with concomitant inhibition of E2F-1 and c-MYC transcripts expressions, while antagomirs of miR-17-5p reversed these events. In conclusion, this study revealed a unique pattern of expression for miR-17-5p in non-metastatic HCC patients in contrast to metastatic HCC patients. In addition we show that miR-17-5p is the key player among the triad that tumor growth and spread.

Progesterone suppresses interferon signaling by repressing TLR-7 and MxA expression in peripheral blood mononuclear cells of patients infected with hepatitis C virus

This study aimed at investigating the effect of progesterone on interferon signaling pathways in peripheral blood mononuclear cells (PBMCs) of patients infected with hepatitis C virus (HCV). PBMCs were isolated from peripheral blood of 38 treatment-naïve HCV-infected patients, pooled, and stimulated with progesterone in the presence and absence of its receptor antagonist, mifepristone, along with interferon alpha (IFN-α) or imiquimod. Toll-like receptor (TLR) 7 and myxovirus resistance protein A (MxA) were quantified in PBMCs using RT-qPCR. Imiquimod alone or combined with progesterone did not change MxA expression in HCV-infected PBMCs. Progesterone decreased the inducing effect of IFN-α on TLR-7 expression in both males and females. Moreover, progesterone stimulation prior to IFN-α treatment attenuated the Jak/STAT pathway, which was reflected by decreased expression of MxA in females. Progesterone showed a negative impact on the IFN signaling pathway in HCV-infected PBMCs as it decreased the expression of TLR-7 in both genders, while MxA expression was decreased only in females.

Tamoxifen alleviates hepatitis C virus-induced inhibition of both toll-like receptor 7 and JAK-STAT signalling pathways in PBMCs of infected Egyptian females

Summary.  Hepatitis C virus (HCV) is a major health concern in Egypt being highly prevalent among Egyptians. The two genders experience different responses to HCV infection and show variations in response to interferon (IFN)-based therapy that may be attributed to sex hormones. We previously demonstrated the suppressive effect of 17β-estradiol (E2) on the expression of the IFN-stimulated gene MxA in HCV-infected peripheral blood mononuclear cells (PBMCs). The selective oestrogen receptor (ER) modulator Tamoxifen has been shown to have an antiviral effect against HCV, but its effect on the host immune response is unknown. We investigated the effect of Tamoxifen on the IFN signalling pathways in PBMCs of HCV-infected Egyptian females. We pooled PBMCs and treated then with exogenous interferon alpha (IFNα) or the TLR7 ligand, Imiquimod, and quantified the relative expressions of MxA using RTqPCR. Studies were performed with and without Tamoxifen pretreatment. Pretreatment with Tamoxifen reversed the suppressive effect of E2 on the JAK-STAT pathway in IFNα-treated PBMCs as indicated by a significant increase in MxA expression (P = 0.05*). Tamoxifen pretreatment also significantly upregulated MxA expression in Imiquimod-treated PBMCs (P = 0.0011**), an effect not ascribed to ER blocking nor to an upregulation in TLR7 expression because Tamoxifen showed no potentiating effect on the expression of the receptor. In conclusion, our findings reveal that Tamoxifen has immunomodulatory effects whereby it enhances the host IFN signalling pathways during HCV infection.

Repressed induction of interferon-related microRNAs miR-146a and miR-155 in peripheral blood mononuclear cells infected with HCV genotype 4

MicroRNAs regulate the expression of many genes and subsequently control various cellular processes, such as the immune response to viral infections mediated by type I interferon (IFN). In this study, the expression pattern of two interferon-related microRNAs, miR-146a and miR-155, was examined in healthy and HCV-genotype-4-infected peripheral blood mononuclear cells (PBMCs) using qRT-PCR. In contrast to other viral infections, the expression pattern was similar in both healthy and infected PBMCs. This could be attributed to attenuation of IFN pathway by HCV, which was assessed by investigating the expression of MxA, an interferon-stimulated gene, that showed lower expression in HCV-infected PBMCs. To determine the site of interference of HCV in the IFN pathway, expression of both microRNAs was examined following stimulation of PBMCs with IFN-α2a, an activator of the JAK/STAT pathway as well as with imiquimod, a toll-like receptor-7 (TLR-7) agonist that promotes interferon release. IFN stimulation induced the expression of miR-146a and miR-155 in HCV-infected and healthy PBMCs. Stimulation with imiquimod led to a down-regulation of both microRNAs in infected PBMCs, while it increased their expression in healthy PBMCs, indicating that HCV might interfere with miR-146a and miR-155 expression at sites upstream of interferon release, specifically in the TLR-7 pathway. The pattern of expression of both miR-146a and miR-155 was very similar with a strong positive correlation, but showed no correlation to the patients' clinical or histopathological parameters or response to treatment. In conclusion, HCV infection might repress the induction of miR-146a and miR-155 by interfering with TLR-7 signaling.

miR-615-5p is restrictedly expressed in cirrhotic and cancerous liver tissues and its overexpression alleviates the tumorigenic effects in hepatocellular carcinoma

microRNAs aberrant behavior in heptocellular carcinoma (HCC) plays a major role in HCC pathogenesis. miR-615-5p expression has never been evaluated in HCC. We showed that miR-615-5p was preferentially expressed in HCC, cirrhotic liver tissues and HCC cell lines, but undetected in normal livers. Forced miR-615-5p expression in HCC cell lines led to significant decrease in cell growth and migration. In-silico predication revealed insulin-like growth factor-II (IGF-II) as a potential downstream target for miR-615-5p. Forcing the expression of miR-615-5p showed downregulation of IGF-II mRNA, as well as inhibition of the luciferase activity in a luciferase reporter vector harboring the IGF-II-3'UTR target sequence. miR-615-5p acts as tumor-suppressor in HCC through targeting IGF-II.

Functional characterization of Fospeg, and its impact on cell cycle upon PDT of Huh7 hepatocellular carcinoma cell model

BACKGROUND

Although several treatment options are available for hepatocellular carcinoma (HCC), their application is mostly restricted to early diagnosed cases or includes liver transplantation, which is rarely available due to donor scarcity. The attractiveness of PDT as a cancer treatment does not only come from its minimal invasiveness, but also from the high selectivity due to tumor localization that can be applied. Precise focusing of light on tumor lesions will result in tumor-specific PDT activation. Novel photosensitizers can be applied in such low concentrations that cells not subjected to irradiation remain healthy. The lethal effect and mechanism of death induction of the photosensitizer Fospeg has never been studied on hepatocellular carcinoma. The aim of the present study is to functionally analyze the impact of PDT on Huh-7 HCC cell line, as well as to analyze its impact on cell cycle protein expression.

METHODS

Cellular viability, and proliferation assays were conducted via MTT and BrdU assay, respectively. Transfected cell models of Huh7 with different constructs harboring cell cycle genes and downstream reporter luciferase gene were generated.

RESULTS

Our results show a statistically significant decrease in both viability and proliferation of Huh-7 cells following PDT, while maintaining Fospeg and laser concentrations far below toxic levels. Proliferative cell cycle genes show a tendency of inhibition, while p53 levels show a significant increase following PDT.

CONCLUSION

Fospeg-mediated PDT is a promising strategy for treatment of hepatocellular carcinoma and needs to be further explored in vivo.

Transcriptional response of MxA, PKR and SOCS3 to interferon-based therapy in HCV genotype 4-infected patients and contribution of p53 to host antiviral response

AIMS

To investigate the myxovirus-resistance protein A (MxA) and double-stranded RNA-activated protein kinase (PKR) genetic response to interferon (IFN) therapy in hepatitis C virus (HCV) genotype 4-infected patients. Moreover, we studied the association between suppressor of cytokine signaling 3 (SOCS3) gene expression and therapy resistance in genotype 4. Finally, we investigated the novel link between p53 and IFN-stimulated genes (ISGs) in humans.

METHODS

Gene expression analyses were performed in peripheral blood using TaqMan real-time PCR. Virologic response was assessed with a branched-DNA assay. Genotyping was confirmed.

RESULTS

Early virologic responders (EVRs, n = 23) but not non-EVRs (n = 7) showed strong upregulation of PKR at week 12 of therapy compared to baseline. Both EVRs and non-EVRs showed MxA upregulation at week 12 compared to baseline. Baseline SOCS3 expression did not distinguish EVRs from non-EVRs in genotype 4. An association was found between p53 and MxA and PKR gene expression.

CONCLUSION

Measurement of MxA and PKR transcriptional induction during treatment may distinguish EVRs from non-EVRs in genotype 4. SOCS3 gene does not seem to be implicated in therapy resistance in genotype 4. An association between p53 and ISGs expression was shown for the first time in HCV-infected patients, further supporting the contribution of p53 to host antiviral response.

Expression signature of microRNA-181-a reveals its crucial role in the pathogenesis of paediatric systemic lupus erythematosus

OBJECTIVES

Systemic lupus erythematosus (SLE) is an autoimmune disease manifested by self-reactive antibodies due to failure of selection in both B and T lymphocytes leading to immune intolerance accompanied by increased rate of apoptosis and deficiency in the clearance of the apoptotic cells. Micro RNAs regulate posttranscriptional gene expression and have been recently identified to regulate cellular differentiation, establishing immunological tolerance and are involved in the pathogenesis of several diseases. miR-181-a, expressed in haematopoietic cell lineage, has shown to be an important modulator of B and T cell differentiation, maturation and function. This study aims to identify the expression signature of miR-181-a in the peripheral blood of paediatric SLE and its regulatory effect on the consequent expression of its target gene PCAF.

METHODS

Twenty SLE paediatrics patients, 9 healthy controls and 4 FMF patients were enrolled in this study. The relative expression of miR-181-a, miR-223, PCAF and Hdm2 were performed using quantitative real time PCR.

RESULTS

For the first time we show that miR-181-a was significantly downregulated in SLE pediatrics as compared to healthy controls. Furthermore, miR-181-a showed significant difference in its expression among groups with different SLEDAI scores. This special signature of miR-181-a expression is unique to SLE as compared to FMF samples which showed a parallel expression to healthy controls. PCAF was upregulated in SLE patients compared to healthy controls, which has an impact on the ubiquitination of Hdm2 and hence releases p53 leading to the induction of apoptosis.

CONCLUSIONS

miR-181-a plays an important role in SLE pathogenesis.

Human atrial myosin light chain 1 expression attenuates heart failure

Most patients with hypertrophic cardiomyopathy and congenital heart diseases express the atrial essential myosin light chains (ALC-1) in their ventricles, replacing the ventricular essential light chains (VLC-1). VLC-1/ALC-1 isoform shift is correlated with increases in cardiac contractile parameters of a transgenic rat model overexpressing hALC-1 in the heart (TGR/hALC-1) compared to normal WKY rats. To investigate, whether the benefical effects of the hALC-1 on cardiac contractility could attenuate contractile failure of the overloaded heart, aortocaval shunt operations of 9-10 weeks old WKY and TGR/hALC-1 were performed. 5 weeks later, both animals groups were sacrificed for analysis of cardiac contraction and transgene expression. Control animals were operated but remained normal body and heart weights. The whole heart contractility parameters were evaluated using the Langendorff heart preparation. Shunt-operated TGR/hALC-1 and WKY rats developed comparable levels of cardiac hypertrophy which was associated with significant reduction of contractile parameters of the Langendorff hearts. However, the decline of cardiac contractility was less pronounced in shunt-operated TGR/hALC-1 compared to shunt-operated WKY. In fact, developed left ventricular pressure as well as maximal velocity of pressure development and relaxation were significantly higher in shunt-operated TGR/hALC-1 as compared to shunt-operated WKY. Expression of hALC-1 was 17 microg/mg whole SDS-protein in control (sham-operated) controls and declined significantly to 14 microg/mg whole SDS-protein in hypertrophied TGR/hALC-1. These results demonstrate that the expression of hALC-1 could have a beneficial effect on the overloaded hypertrophied heart.

Functional characterization of the human atrial essential myosin light chain (hALC-1) in a transgenic rat model

Most patients with hypertrophic cardiomyopathy and congenital heart diseases express the atrial essential myosin light chains (ALC-1) in their ventricles, partially replacing the ventricular essential light chains (VLC-1). This VLC-1/ALC-1 isoform shift is correlated with an increase in cross-bridge cycling kinetics as measured using skinned fibers from the hypertrophied ventricles of human hearts. To study the functional importance of hALC-1 in the intact perfused heart, we generated a transgenic rat model (TGR) overexpressing hALC-1 in the heart. Twelve-week-old TGR rats expressed 17 +/- 4 microg hALC-1 per mg of whole SDS-soluble protein. Their perfused heart contractility parameters were evaluated using the Langendorff preparation. Expression of hALC-1 was accompanied by statistically significant improvements (P<0.001) in the contractile parameters of the hearts of the TGR compared to the age matched control (WKY) animals, represented by increases from 20.8 +/- 2.3 to 45.1 +/- 3.6 mmHg/g heart weight in the developed left ventricular pressure, 1,035.7 +/- 89.8 to 2,181 +/- 135.4 mmHg/s in the contraction rate, and 713 +/- 60.2 to 1,364 +/- 137.4 mmHg/s in the relaxation rate in the WKY and the TGR groups respectively. Characterizing the functional effects of hALC-1 at the whole organ level represents a step towards gene therapy of heart failure.