APOBEC3B stratifies ovarian clear cell carcinoma with distinct immunophenotype and prognosis.

BACKGROUND: Ovarian clear cell carcinoma (OCCC) is a challenging disease due to its intrinsic chemoresistance. Immunotherapy is an emerging treatment option but currently impeded by insufficient understanding of OCCC immunophenotypes and their molecular determinants. METHODS: Whole-genome sequencing on 23 pathologically confirmed patients was employed to depict the genomic profile of primary OCCCs. APOBEC3B expression and digital pathology-based Immunoscore were assessed by performing immunohistochemistry and correlated with clinical outcomes. RESULTS: An APOBEC-positive (APOBEC+) subtype was identified based on the characteristic mutational signature and prevalent kataegis events. APOBEC + OCCC displayed favourable prognosis across one internal and two external patient cohorts. The improved outcome was ascribable to increased lymphocytic infiltration. Similar phenomena of APOBEC3B expression and T-cell accumulation were observed in endometriotic tissues, suggesting that APOBEC-induced mutagenesis and immunogenicity could occur early during OCCC pathogenesis. Corroborating these results, a case report was presented for an APOBEC + patient demonstrating inflamed tumour microenvironment and clinical response to immune checkpoint blockade. CONCLUSIONS: Our findings implicate APOBEC3B as a novel mechanism of OCCC stratification with prognostic value and as a potential predictive biomarker that may inform immunotherapeutic opportunities.

Identification of a 4-lncRNA signature predicting prognosis of patients with non-small cell lung cancer: a multicenter study in China.

BACKGROUND: Previous findings have indicated that the tumor, nodes, and metastases (TNM) staging system is not sufficient to accurately predict survival outcomes in patients with non-small lung carcinoma (NSCLC). Thus, this study aims to identify a long non-coding RNA (lncRNA) signature for predicting survival in patients with NSCLC and to provide additional prognostic information to TNM staging system. METHODS: Patients with NSCLC were recruited from a hospital and divided into a discovery cohort (n = 194) and validation cohort (n = 172), and detected using a custom lncRNA microarray. Another 73 NSCLC cases obtained from a different hospital (an independent validation cohort) were examined with qRT-PCR. Differentially expressed lncRNAs were determined with the Significance Analysis of Microarrays program, from which lncRNAs associated with survival were identified using Cox regression in the discovery cohort. These prognostic lncRNAs were employed to construct a prognostic signature with a risk-score method. Then, the utility of the prognostic signature was confirmed using the validation cohort and the independent cohort. RESULTS: In the discovery cohort, we identified 305 lncRNAs that were differentially expressed between the NSCLC tissues and matched, adjacent normal lung tissues, of which 15 are associated with survival; a 4-lncRNA prognostic signature was identified from the 15 survival lncRNAs, which was significantly correlated with survivals of NSCLC patients. This signature was further validated in the validation cohort and independent validation cohort. Moreover, multivariate Cox analysis demonstrates that the 4-lncRNA signature is an independent survival predictor. Then we established a new risk-score model by combining 4-lncRNA signature and TNM staging stage. The receiver operating characteristics (ROC) curve indicates that the prognostic value of the combined model is significantly higher than that of the TNM stage alone, in all the cohorts. CONCLUSIONS: In this study, we identified a 4-lncRNA signature that may be a powerful prognosis biomarker and can provide additional survival information to the TNM staging system.

Development and external validation of nomograms for predicting individual survival in patients with ovarian clear cell carcinoma.

PURPOSE: Ovarian clear cell carcinoma (OCCC) is a distinct and highly malignant subtype of ovarian cancer with high individual heterogeneity in survival that requires specific prognostic predictive tools. Thus, this study aimed to construct and validate nomograms for predicting individual survival in OCCC patients. METHODS: In total, 91 patients with OCCC who were diagnosed and treated at Renji Hospital between 2010 and 2020 were extracted as the training cohort, then 86 patients from the First Affiliated Hospital of USTC were used as the external validation cohort. Prognostic factors that affect survival were identified using least absolute shrinkage and selection operator regression. Nomograms of progression-free survival (PFS) and overall survival (OS) were then established with the Cox regression model and the performance was subsequently evaluated using the concordance index (C-index), calibration plots, decision curve analysis (DCA), and risk subgroup classification. RESULTS: Advanced tumor, ascites of >400 mL, lymph node-positive, CA199 of >142.3 IU/mL, and fibrinogen of >5.36 g/L were identified as risk factors for OS while advanced tumor, ascites of >400 mL, lymph node-positive, and fibrinogen of >5.36 g/L were risk factors for PFS. The C-indexes for the OS and PFS nomograms were 0.899 and 0.731 in the training cohort and 0.804 and 0.787 in the validation cohort, respectively. The calibration plots showed that nomograms could provide better consistency in predicting patient survival than the FIGO staging system. DCA also demonstrated that nomograms were more clinically beneficial than the FIGO staging system. Additionally, patients could be classified into two risk groups based on scores using nomograms, with significant survival differences. CONCLUSIONS: We developed nomograms that could more objectively and reliably predict the individual survival of patients with OCCC compared with the FIGO staging system. These tools might assist in clinical decision-making and management of patients with OCCC to improve their survival outcomes.

LncRNA GAS5 suppresses ovarian cancer progression by targeting the miR-96-5p/PTEN axis.

BACKGROUND: Long non-coding RNAs (lncRNAs) play critical roles in the occurrence and progression of various tumors, including ovarian cancer (OC). The lncRNA growth arrest-specific transcript 5 (GAS5) has been shown to be an important modulator in the growth and metastasis of OC cells. Our previous studies confirmed that GAS5 was down-regulated in OC; however, the potential underlying molecular mechanism underlying has not yet been elucidated. METHODS: We screened the Gene Expression Profiling Interactive Analysis (GEPIA) database for the expression of the lncRNA GAS5 in OC. Cell Counting Kit-8 (CCK-8), transwell assay, colony formation assay, flow cytometry analysis, and western blotting were applied to determine the various functions of GAS5 in OC progression. The competing endogenous RNA (ceRNA) mechanism was verified through bioinformatics analysis, dual-spectral luciferase reporter gene assay, and RNA immunoprecipitation assay (RIPA). Finally, the expression interactions between microRNA-96-5p, phosphatase and tensin homolog deleted on chromosome ten (PTEN), and GAS5 were measured. RESULTS: Our results demonstrated decreased expression levels of GAS5 and PTEN in OC samples and cell lines, while miR-96-5p was up-regulated when compared with the controls. GAS5 overexpression could significantly reduce OC cell proliferation and invasion ability via suppression of miR-96-5p expression. Moreover, GAS5 could influence the PTEN/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) signaling pathway. CONCLUSIONS: Our study identified GAS5 as a ceRNA that can regulate the PTEN/AKT/mTOR axis by sponging miR-96-5p in OC.

Lnc-GAN1 expression is associated with good survival and suppresses tumor progression by sponging mir-26a-5p to activate PTEN signaling in non-small cell lung cancer.

BACKGROUND: Long non-coding RNAs (lncRNAs) play vital roles in the development and progression of non-small-cell lung cancer (NSCLC); however, the role of most lncRNAs in NSCLC remains unknown. This study explored the clinical significance, biological function and underlying mechanism of lnc-GAN1 in NSCLC. METHODS: With a custom lncRNA microarray we found that lnc-GAN1 is markedly downregulated in NSCLC tissues. Then lnc-GAN1 expression level was measured using qRT-PCR in NSCLC tissues and cell lines. Survival was assessed using the Kaplan-Meier method. The biological functions of lnc-GAN1 in lung cancer cells were evaluated in vitro and in vivo. RNA fluorescence in situ hybridization and subcellular localization assays revealed the subcellular distribution of lnc-GAN1 in cells. Bioinformatic analysis was adopted to predict miRNAs and signaling pathways regulated by lnc-GAN1. RNA immunoprecipitation and Dual-luciferase reporter assays were used to assess the interaction between lnc-GAN1 and miR-26a-5p in lung cancer cells. RESULTS: lnc-GAN1 is downregulated in HCC tissues and associated with larger tumor size and poor overall survival and disease-free survival; its ectopic expression suppresses cell proliferation, colony formation, and cell cycle progression and induces apoptosis in NSCLC cells; it also inhibits tumor growth in the NSCLC xenograft model. We further proved that lnc-GAN1 is localized in cytoplasm and transcribed independently from its parental gene GAN. Mechanistically, lnc-GAN1 acts as a sponge for miR-26a-5p by two seed sequences, and the two non-coding RNAs have a negative relationship in NSCLC tissues; we further prove that PTEN is a direct target of miR-26a-5p and lnc-GAN1 inhibits cell cycle signaling pathway by activating PTEN, whose expression level correlated negatively with miR-26a-5p level but positively with lnc-GAN1 level in NSCLC samples. CONCLUSIONS: Lnc-GAN1 is downregulated and associated with poor survival of NSCLC patients, and mechanistically acts as a tumor suppressor via sponging and inhibiting miR-26a-5p to upregulate PTEN. This study provides a potential prognostic biomarker and treatment target for NSCLC.

Follicle-stimulating hormone promotes the proliferation of epithelial ovarian cancer cells by activating sphingosine kinase.

Follicle-stimulating hormone (FSH) is closely related to the pathogenesis and progression of epithelial ovarian cancer (EOC). However, until now, knowledge relating to FSH-driven signalling pathways that lead to the growth of EOC remained incomplete. We sought to explore whether sphingosine kinase (SphK) could mediate FSH-induced ovarian cancer cell proliferation and which pathway might be involved in this process. The expression of phospho-SphK1 and phospho-SphK2 was detected in sections of EOC tissues by Immunohistochemical staining, and clinical significances were analyzed by statistical analysis. EOC cells were treated with FSH or/and SKI-II. CCK8 assays and colony formation assays were used to investigate cell proliferation. Western blot was carried out to detect protein expression in EOC cell line after treated with FSH. Here, for the first time, we provide evidence that high expression levels of phospho-SphK1 and phospho-SphK2 were both prognostic indicators of overall survival (OS) in EOC. Additionally, the expression levels of both phospho-SphK1 and phospho-SphK2 were closely correlated with the expression level of follicle-stimulating hormone receptor (FSHR) in ovarian cancer tissues. FSH stimulated the phosphorylation of both SphK1 and SphK2 and was able to regulate the survival and growth of ovarian cancer cells by activating SphK1 and SphK2 through ERK1/2. Both isoenzymes of SphK were equally responsible for FSH-induced cell proliferation of EOC. Both Erk1/2 and Akt activation play important roles in mediating FSH-induced cell proliferation after phosphorylation of SphK. Moreover, our data demonstrated that S1P receptor 1 (S1PR1) and S1PR3, key components of the SphK signalling system, were involved in FSH-mediated proliferation of EOC. Taken together, the results of the current study revealed that SphK is an essential mediator in FSH-induced proliferation of ovarian cancer cells in EOC, which indicates a new signalling pathway that controls FSH-mediated growth in EOC and suggests a new strategy that pharmaceutically targets both isoenzymes of SphK for the management of ovarian cancer.

Sphingosine kinase 2 inhibitor ABC294640 displays anti-epithelial ovarian cancer activities in vitro and in vivo.

Background: ABC294640 is a non-lipid competitive inhibitor of SphK2. It exhibited anti-proliferative activities in many human malignancies, including ovarian cancer. However, its potential mechanism of action remains poorly understood. Methods: In this paper, epithelial ovarian cancer (EOC) cell lines SKOV3 and HO8910 were treated with ABC294640. In order to explore the effect of ABC294640 on the behavior of ovarian cancer cells in vitro, we used cell counting kit-8 (CCK-8) assays, colony formation assays, flow cytometry, quantitative real-time PCR (qRT-PCR), Western blot analysis and immunohistochemistry to detect the effect of ABC294640 on cell proliferation, cell cycle distribution, cell apoptosis, the expression of related factors at mRNA levels, and the expression of related factors at protein level. An intra-abdominal xenograft tumor model of EOC was set up to assess the tumor growth in nude mice. Results: The results obtained indicate that EOC cell proliferation was noticeably inhibited in a concentration-dependent manner by ABC294640. ABC294640 caused cell cycle arrest in S phase and increased cell apoptosis rate in EOC cells. Also, the proteins, including phosphorylated retinoblastoma protein (P -Rb), cyclin D1, cyclin B1, and Bcl-2 were significantly inhibited, while cleaved-caspase 3 was activated. ABC294640 inhibited the expression of c-Myc in EOC. The in vivo assay showed an inhibitory effect of ABC294640 on tumor growth. Conclusions: ABC294640 could downregulate the expression of c-Myc in EOC both in vitro and in vivo. ABC294640 inhibited tumor growth in EOC via cell cycle arrest and inducing cell apoptosis both in vitro and in vivo, partially by decreasing the expression of cell cycle-associated proteins (such as P-Rb, cyclin B1, and cyclin D1) and promoting caspase 3 activation via downregulation expression of c-Myc. It suggested that ABC294640 had the potential to serve as an agent in EOC treatment.

Long non-coding RNA GAS5 inhibits DDP-resistance and tumor progression of epithelial ovarian cancer via GAS5-E2F4-PARP1-MAPK axis.

BACKGROUND: Epithelial ovarian cancer (EOC) is the malignant tumor of the female reproductive system with the highest fatality rate. Tolerance of chemotherapeutic drugs like cisplatin (DDP) occurring in very early stage is one of the important factors of the poor prognosis of epithelial ovarian cancer. Here we aim to study the dysregulation of a particular long noncoding RNA, lncRNA GAS5, and its role in EOC progression. METHODS: The low expression of lncRNA GAS5 in EOC tissues and OC cell lines was determined by microarray analyses and Real-Time qPCR. Flow cytometer assays were used to detect cell cycle and apoptosis of OC cells. CCK8 assay were performed to investigate the DDP sensitivity of OC cells. Western blot was carried out to detect cell growth markers, apoptotic markers, PARP1, E2F4, MAPK pathway protein expression and other protein expression in OC cell lines. The binding of GAS5 and E2F4 were proved by RNA pull-down and RIP assay. The effect of E2F4 on PARP1 were determined by CHIP-qPCR assay and luciferase reporter assay. The effect of lncRNA GAS5 on OC cells was assessed in vitro and in vivo. RESULTS: By microarray (3 EOC tissues νs. 3 normal ovary tissues) and RT- qPCR (53 EOC tissues νs. 10 normal ovary tissues) we identified lncRNA GAS5 to be dramatically low expressed in EOC samples and correlated with prognosis. Compared with sensitive cell lines, GAS5 was also low expressed in DDP resistant OC cell lines, and over-expression of GAS5 significantly enhanced the sensitivity of OC cells to DDP in vivo and in vitro. Meanwhile the over-expression of GAS5 also caused OC cells G0/G1 arrest and apoptosis increase. Mechanistically, GAS5 might regulate PARP1 expression by recruiting the transcription factor E2F4 to its promoter, and then affect the MAPK pathway activity. Due to the 5'TOP structure, GAS5 could be regulated by transcription inhibitor rapamycin in OC cells. CONCLUSION: Here we explored the specific mechanisms of EOC cisplatin resistance and tumor progress due to lncRNA-GAS5, presented the GAS5-E2F4-PARP1-MAPK axis and its role in OC drug-sensitivity and progression for the first time, and the results may provide experimental basis for clinical application.

Identification of an 88-microRNA signature in whole blood for diagnosis of hepatocellular carcinoma and other chronic liver diseases.

Hepatocellular carcinoma (HCC) is a common cancer with very poor survival due to lack of reliable biomarker for early diagnosis. In this study, we investigated microRNA (miRNA) profile of whole blood with a custom microarray containing probes for 1849 miRNA species in a total 213 successive subjects who were divided into a discovery set and a validation set. An 88-miRNA signature was established to diagnose health controls (HC), chronic hepatitis B (CHB), liver cirrhosis (LC) and HCC with 100% accuracy in the discovery set using Fisher discriminant analysis. This diagnostic signature was confirmed in the validation set with accuracy rates of 100%, 95.2%, 93.7% and 98.4% for HC, CHB, LC and HCC patients, respectively. Compared with AFP, the only available non-invasive and routinely used biomarker for diagnosis of HCC, the 88-miRNA signature has much higher accuracy (99.5% vs 76.5%), sensitivity (100% vs 63.8%), and specificity (99.2% vs 84.2%). More importantly, the signature detects small HCCs (<3cm) with 100% (17/17) accuracy while AFP has only 64.7% (11/17). In conclusion, we have identified a powerful and sensitive blood 88-miRNA signature for diagnosing early HCC and other chronic liver diseases (CHB and LC) with a high accuracy.

MicroRNA-711 is a prognostic factor for poor overall survival and has an oncogenic role in breast cancer.

MicroRNAs are important in cancer development and progression. In the present study, the clinical significance and function of microRNA-711 (miR-711) expression in breast cancer were investigated. The expression level of miR-711 was analyzed in breast cancer tissue samples using reverse transcription-quantitative polymerase chain reaction. Cell proliferation, colony formation, apoptosis and Transwell assays were performed in breast cancer cell lines transfected with miR-711 mimics or inhibitors, or control sequence. miR-711 was found to be upregulated in 30 formalin-fixed paraffin-embedded breast cancer tissue samples compared with paired non-cancerous breast tissues (P<0.05). Furthermore, a higher miR-711 expression was demonstrated to be associated with poor overall and disease-free survival times in 161 breast cancer patients, and miR-711 was identified as an independent prognostic factor using multivariate Cox regression analysis. In vitro, overexpression of miR-711 resulted in a significant increase in proliferation, colony formation, migration and invasion of breast cancer cells. By contrast, downregulating miR-711 inhibited cell proliferation, colony formation, migration and invasion and enhanced the rate of apoptosis of breast cancer cells. To the best of our knowledge, the present study is the first to demonstrate that miR-711 is an independent prognostic factor and serves an important oncogenic function in breast cancer, suggesting that miR-711 is a potential biomarker of prognosis and a molecular therapeutic target in breast cancer.

Comparison of treatment safety and patient survival in elderly versus nonelderly patients with advanced hepatocellular carcinoma receiving sorafenib combined with transarterial chemoembolization: a propensity score matching study.

AIMS: This retrospective study was carried out to compare the outcomes between elderly (≥70 years of age) and nonelderly patients (<70 years of age) with advanced hepatocellular carcinoma (HCC) who received sorafenib combined with transarterial chemoembolization (TACE). METHODS: 88 patients with a confirmed diagnosis of advanced HCC were enrolled in this study. Of these, 24 elderly patients were matched with 48 nonelderly patients at a 1:2 ratio using propensity score matching to minimize selection bias. The related adverse events and survival benefits were compared between the two groups. RESULTS: Sorafenib combined with TACE was equally well tolerated in both age groups, and grade 3 or 4 adverse events were similarly observed in 54.2% of elderly and 50.0% of nonelderly patients (P = 0.739). There were no significant differences in survival time between the elderly and nonelderly patients (P = 0.876). Significant prognostic factors for overall survival as identified by multivariate analysis were the Child-Pugh score and portal vein invasion. CONCLUSIONS: Sorafenib combined with TACE may be well tolerated and effective in elderly patients with advanced HCC. Age alone is not a parameter for the treatment of advanced HCC patients.

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). miR­148a, 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.

Sorafenib combined with transarterial chemoembolization versus transarterial chemoembolization alone for advanced-stage hepatocellular carcinoma: a propensity score matching study.

AIMS: The purpose of the present study was to compare the efficacies of transarterial chemoembolization (TACE) combined with sorafenib versus TACE monotherapy for treating patients with advanced hepatocellular carcinoma (HCC). METHODS: We enrolled 321 patients and selected 280 with advanced HCC (Barcelona Clinic Liver Cancer stage C) who underwent TACE therapy between February 2009 and February 2013. TACE alone (monotherapy group) was administered to 198 patients (70.7%), and the remaining 82 (29.3%) underwent repeat combined TACE and sorafenib therapy (combined group). To minimize selection bias, these latter 82 patients were matched using propensity-score matching at a 1∶2 ratio with 164 patients who received TACE monotherapy. The primary endpoints were overall survival (OS) and related subgroup analysis. The secondary endpoints were time to progression (TTP) and treatment-related adverse events. RESULTS: Of the respective patients in the combined and monotherapy groups, 64.6% and 49.2% had vascular invasion, 87.8% and 91.1% had extrahepatic metastasis, and 54.3% and 47.1% had both. In the propensity-score-matched cohort, the OS survival of the combined group was significantly higher compared with the monotherapy group (7.0 months vs. 4.9 months, respectively, P = 0.003). The TTP was significantly longer in the combined group (2.6 months vs. 1.9 months, respectively, P = 0.001). Subgroup analysis showed that the outcomes of patients with advanced HCC without main portal vein invasion who were treated with combined therapy were significantly better compared with those who received monotherapy (P<0.05). Univariate and subsequent multivariate analyses revealed that the addition of sorafenib was an independent predictor of favorable OS and TTP (adjusted hazard ratios, 0.63 and 0.62, respectively; P<0.05 for both). CONCLUSION: Sorafenib plus TACE was more effective than TACE monotherapy for treating patients with advanced HCC without main portal vein invasion. Future trials with larger samples are required to validate these preliminary findings.

MiR-146a regulates IL-6 production in lipopolysaccharide-induced RAW264.7 macrophage cells by inhibiting Notch1.

Inflammatory cells, macrophages induced by lipopolysaccharide (LPS) stimulation, lead to the production of inflammatory cytokines, which are crucial to host defense. MicroRNAs are short noncoding RNAs that regulate key biological processes via suppression of gene expression at posttranscriptional levels. Recently, miR-146a has been shown to be involved in the regulation of immune and inflammatory responses. However, the role of miR-146a in LPS-induced RAW264.7 macrophage cells remains unclear. In this study, we found that the expression of miR-146a was upregulated in RAW264.7 macrophage cells in response to LPS stimulation in a dose- and time-dependent manner by one-step real-time quantitative PCR. In addition, miR-146a mimics decreased, while miR-146a inhibitor increased, the expression of inflammatory cytokine interleukin-6, but did not affect tumor necrosis factor-α expression in LPS-stimulated RAW264.7 macrophage cells. Bioinformatics analyses predict that Notch1 is a potential target of miR-146a. Moreover, miR-146a overexpression in LPS-treated RAW264.7 macrophage cells did significantly decrease Notch1 mRNA and protein levels. These results suggested that miR-146a may function as a novel feedback negative regulator to LPS-induced production of inflammatory cytokines, at least in part, via inhibiting the expression of Notch1.

The potential of microRNAs in liver fibrosis.

MicroRNAs (miRNAs) are a class of ~22-nucleotides noncoding RNAs that regulate gene expression by specifically binding with 3'-untranslated region (3'-UTR) of target gene mRNAs to posttranscriptionally effect mRNA stability and translation,and play essential roles in a variety of biological processes, including cell development, proliferation, differentiation, and apoptosis. Liver fibrosis is the occurrence of liver cell necrosis and inflammatory stimulation, and is characterized by excessive accumulation of extracellular matrices(ECMs). In the fibrotic liver, hepatic stellate cells (HSCs), which are regulated by multiple signal transduction pathways, undergo myofibroblastic transdifferentiation and are generally regarded as the major ECM producer responsible for liver fibrosis. A growing body of evidence suggests that divergent miRNAs participate in liver fibrotic process and activation of HSC. Moreover, members of many signal transduction pathways are important targets for miRNAs. In this review, we make a summary on current understanding of the roles of miRNAs in the development of liver fibrosis, HSC functions and their potential as novel drug targets.

MicroRNA-146a modulates TGF-beta1-induced hepatic stellate cell proliferation by targeting SMAD4.

Activation of hepatic stellate cells (HSC) plays a pivotal role in the development of hepatic fibrosis. Transforming growth factor-ß1 (TGF-ß1) is considered to be the main stimuli factor responsible for the activation of HSC. MicroRNAs (miRNAs) have recently been shown to regulate cell proliferation, differentiation, and apoptosis. The involvement of miRNAs and their roles in TGF-ß1-induced HSC activation remains largely unknown. Our study found that the expression of miR-146a was downregulated in HSC in response to TGF-ß1 stimulation in dose-dependent manner by one-step real-time quantitative PCR. Moreover, we sought to examine whether miR-146a became dysregulated in CCl(4)-induced hepatic fibrosis in rats. Our study revealed that miR-146a was downregulated in liver fibrotic tissues. In addition, The HSC transfected with miR-146a mimics exhibited attendated TGF-ß1-induced α-smooth muscle actin (α-SMA) expression compared with the control. Furthermore, overexpression of miR-146a suppressed TGF-ß-induced HSC proliferation, and increased HSC apoptosis. Bioinformatics analyses predict that SMAD4 is the potential target of miR-146a. MiR-146a overexpression in TGF-ß1-treated HSC did not decrease target mRNA levels, but significantly reduced target protein expression. These results suggested that miR-146a may function as a novel regulator to modulate HSC activation during TGF-ß1 induction by targeting SMAD4.