Wei-hui Liu

Downregulation of miR-200a Induces EMT Phenotypes and CSC-like Signatures through Targeting the β-catenin Pathway in Hepatic Oval Cells

Hepatocellular carcinoma (HCC) can be derived from malignant transformed adult hepatic progenitor cells. However, the regulatory factors and molecular mechanisms underlying the process are not well defined. Our previous microRNA (miRNA) microarray analysis revealed a significant decrease of miR-200a level in F344 rat HCC side population (SP) fraction cells versus their normal counterparts. In the present study, we further investigated the effect of miR-200a on hepatic oval cell (HOC) phenotypes. We first confirmed downregulated miR-200a levels in rat hepatoma cells compared with WB-F344 cells. Next, by lentivirus-mediated loss-of-function studies, we showed that stable knockdown of miR-200a confers a mesenchymal phenotype to WB-F344 cells, including an elongated cell morphology, enhanced cell migration ability and expression of epithelial mesenchymal transition (EMT)-representative markers. Concomitantly, several cancer stem cell (CSC)-like traits appeared in these cells, which exhibit enhanced spheroid-forming capacity, express putative hepatic CSC markers and display superior resistance to chemotherapeutic drugs in vitro. Furthermore, bioinformatics analysis, luciferase assays and western blot analysis identified β-catenin (CTNNB1) as a direct and functional target of miR-200a. Knockdown of miR-200a partially activated Wnt/β-catenin signaling, and silencing of β-catenin functionally attenuated anti-miR-200a effects in vitro in WB-F344 cells. At length, in vivo xenograft assay demonstrated the acquisition of tumorigenicity of WB-F344 cells after miR-200a siliencing. Collectively, our findings indicate that miR-200a may function as an important regulatory factor in neoplastic transition of HOCs by targeting the β-catenin pathway.

The multiple functional roles of mesenchymal stem cells in participating in treating liver diseases

Mesenchymal stem cells (MSCs) are a group of stem cells derived from the mesodermal mesenchyme. MSCs can be obtained from a variety of tissues, including bone marrow, umbilical cord tissue, umbilical cord blood, peripheral blood and adipose tissue. Under certain conditions, MSCs can differentiate into many cell types both in vitro and in vivo, including hepatocytes. To date, four main strategies have been developed to induce the transdifferentiation of MSCs into hepatocytes: addition of chemical compounds and cytokines, genetic modification, adjustment of the micro‐environment and alteration of the physical parameters used for culturing MSCs. Although the phenomenon of transdifferentiation of MSCs into hepatocytes has been described, the detailed mechanism is far from clear. Generally, the mechanism is a cascade reaction whereby stimulating factors activate cellular signalling pathways, which in turn promote the production of transcription factors, leading to hepatic gene expression. Because MSCs can give rise to hepatocytes, they are promising to be used as a new treatment for liver dysfunction or as a bridge to liver transplantation. Numerous studies have confirmed the therapeutic effects of MSCs on hepatic fibrosis, cirrhosis and other liver diseases, which may be related to the differentiation of MSCs into functional hepatocytes. In addition to transdifferentiation into hepatocytes, when MSCs are used to treat liver disease, they may also inhibit hepatocellular apoptosis and secrete various bioactive molecules to promote liver regeneration. In this review, the capacity and molecular mechanism of MSC transdifferentiation, and the therapeutic effects of MSCs on liver diseases are thoroughly discussed.

Replacing Hoechst33342 with rhodamine123 in isolation of cancer stem-like cells from the MHCC97 cell line.

The side population (SP) is commonly applied to analyzing cancer stem cells (CSCs) biology. However, the Hoechst33342 (Hoechst) dye, which is used for SP isolation, is demonstrated to be toxic to cells. The aim of this study was to identify a dye that might replace or offer an alternative to Hoechst use. In the trial group, by FACS binding Rhodamine123 (Rho), Rho(low) (low Rho fluorescence) and Rho(high) (high Rho fluorescence) were sorted from the MHCC97 cell line. In the control group, SP (low Hoechst fluorescence) and NSP (high Hoechst fluorescence) were obtained through Hoechst/FACS. The percentages of subpopulations were as following: Rho(low) 2.1%, Rho(high) 97.9%, SP 1.4%, NSP 98.6%. The proliferative abilities in vitro (growth rate, soft agar clone formation rate), expressions of stem cell markers (early hepatic marker AFP and CSCs marker CD133), and tumorigenicities in vivo were significantly higher in the Rho(low) and SP cells than those in the Rho(high) and NSP cells, respectively (P<0.05). In addition, each result was the same between the Rho(low) and SP cells (P>0.05). Taken together, Rho/FACS may not be as effective as Hoechst/FACS for CSCs sorting, but given its low toxicity and cost, it may be a useful method for CSCs identification.

Convenient and Efficient Enrichment of the CD133+ Liver Cells from Rat Fetal Liver Cells as a Source of Liver Stem/Progenitor Cells

Although the stem cells are commonly isolated by FACS or MACS, they are very expensive and these is no specific marker for liver stem/progentior cells (LSPCs). This paper applied a convenient and efficient method to enrich LSPCs. The fetal liver cells (FLCs) were firstly enriched by Percoll discontinuous gradient centrifugation (PDGC) from the rat fetal liver. Then the FLCs in culture were purified to be homogeneous in size by differential trypsinization and differential adherence (DTDA). Flow cytometric analysis revealed more than half of the purified FLCs expressed alternative markers of LSPCs (CD117, c-Met, Sca-1, CD90, CD49f and CD133). In other words, the purified FLCs were heterogeneous. Therefore, they were sequentially layered into six fractions by Percoll continuous gradient centrifugation (PCGC). Both CD133 and CD49f expressed decreasingly from fraction 1 to 6. In fraction 1 and 2, about 85% FLCs expressed CD133, which were revealed to be LSPCs by high expressions of AFP and CK-19, low expressions of G-6-P and ALB. To conclude, the purity of CD133+ LSPCs enriched by combination of PDGC, DTDA and PCGC is close to that obtained by MACS. This study will greatly contribute to two important biological aspects: liver stem cells isolation and liver cell therapy.

Enhancing HOTAIR/MiR-10b Drives Normal Liver Stem Cells Toward a Tendency to Malignant Transformation Through Inducing Epithelial- to-Mesenchymal Transition

Previously, other groups and our team consistently have demonstrated that the possible origination of liver cancer stem cells (LCSCs) is the malignant transformation from liver normal stem cells (LNSCs). However, this complex and multi-step process is far from clear due to the accumulation of various gene dysregulations. Because non-coding RNAs (ncRNAs) could regulate multiple genes, a family of genes, and even whole chromosomes, this study further investigated the effect of dysregulated short ncRNA microRNA-10b and long ncRNA HOX transcript antisense RNA (HOTAIR) between LNSCs and LCSCs on phenotype reversion. To clarify the role of ncRNA in malignant transformation of LNSCs, we used lentivirus transduction to enhance the miR-10b and HOTAIR expression levels in our previously isolated rat LNSCs. The malignant abilities of proliferation, invasiveness, and tumorigenesis were observed and compared in cells before and after ncRNAs enhancement. After microRNA-10b and HOTAIR were enhanced separately, several cancer stem cell (CSC)-like traits appeared in these LNSCs, including in vitro-enhanced proliferative capacity, expression of putative LCSC markers, progressive invasive ability, and even in vivo aggravation into and taking the place of normal liver tissue. Furthermore, strengthened expression of these ncRNAs partially degraded E-cadherin in LNSCs, which is one of the classic markers in epithelial-to-mesenchymal transition (EMT). HOTAIR or miR-10b enhanced in LNSCs may drive the LNSCs to a tendency toward malignant transformation. This study partially uncovers the mechanism by which miR-10b or HOTAIR promotes malignant transformation of LNSCs through down-regulating E-cadherin and inducing EMT.

Benefcial effects of splenectomy on liver regeneration in a rat model of massive hepatectomy

BACKGROUND Small-for-size syndrome is a widely recognized clinical complication after living donor liver transplantation or extended hepatectomy due to inadequate liver mass. The purpose of this study was to investigate the role of splenectomy in rats after massive hepatectomy, a surrogate model of small-for-size graft. METHODS Rats were divided into eight groups, each with 20 animals: 50% hepatectomy (50% Hx), 50% hepatectomy+splenectomy (50% Hx+Sp), 60% Hx, 60% Hx+Sp, 70% Hx, 70% Hx+Sp, 90% Hx and 90% Hx+Sp. The following parameters were evaluated: liver function tests (ALT, AST and TBIL), liver regeneration ratio, DNA synthesis, proliferation cell nuclear antigen, hepatic oxygen delivery (HDO2) and hepatic oxygen consumption (HVO2). RESULTS The liver regeneration ratio was enhanced in the Hx+Sp groups (P<0.05). In addition, compared with the Hx groups, the Hx+Sp groups had better liver functions (P<0.05). DNA synthesis and proliferation cell nuclear antigen were also increased in the Hx+Sp groups compared with the Hx groups (P<0.05). Furthermore, in the Hx+Sp groups, HDO2 and HVO2 were increased over those in the Hx groups (P<0.05), and were positively correlated with the liver regeneration ratio. CONCLUSIONS Splenectomy significantly improved liver function, and enhanced DNA synthesis and proliferation cell nuclear antigen after massive hepatectomy in rats. This operation could be mediated through increased HDO2 and HVO2, which facilitate liver regeneration.

Abdominal paracentesis drainage ahead of percutaneous catheter drainage benefits patients attacked by acute pancreatitis with fluid collections: a retrospective clinical cohort study.

Objective:The efficacy and safety of ultrasound-guided abdominal paracentesis drainage ahead of percutaneous catheter drainage as the new second step of a step-up approach are evaluated. Design:The observed parameters were compared between groups including mortality, infection, organ failure, inflammatory factor levels, indexes of further interventions, and drainage-related complications. Patients:This retrospective study included 102 consecutive patients with acute pancreatitis from June 2009 to June 2011. Interventions:In this step-up approach, all patients subsequently received medical management, percutaneous catheter drainage (with or without previous abdominal paracentesis drainage), and necrosectomy if necessary according to indications. The patients were divided into two groups: 53 cases underwent abdominal paracentesis drainage followed by percutaneous catheter drainage (abdominal paracentesis drainage + percutaneous catheter drainage group) and 49 cases were managed only with percutaneous catheter drainage (percutaneous catheter drainage-alone group). Measurements and Main Results:The demographic data and severity scores of the two groups were comparable. The mortality rate was lower in the abdominal paracentesis drainage + percutaneous catheter drainage group (0%) than the percutaneous catheter drainage–alone group (8.2%) (p = 0.050). Compared with the percutaneous catheter drainage–alone group, the laboratory variables of the abdominal paracentesis drainage + percutaneous catheter drainage group decreased more rapidly, the mean number of failed organs was lower, and the interval from the onset of disease to further interventions was much longer. However, there was no significant difference in the prevalence and duration of infections between the two groups. Conclusion:Application of abdominal paracentesis drainage ahead of percutaneous catheter drainage is safe and beneficial to patients by reducing inflammatory factors, postponing further interventions, and delaying or avoiding multiple organ failure.

Upregulated MicroRNA-92b Regulates the Differentiation and Proliferation of EpCAM-Positive Fetal Liver Cells by Targeting C/EBPß

microRNAs (miRNAs) are short noncoding RNAs that negatively regulate gene expression. Although recent evidences have been indicated that their aberrant expression may play an important role in cancer stem cells, the mechanism of their deregulation in neoplastic transformation of liver cancer stem cells (LCSCs) has not been explored. In our study, the HCC model was established in F344 rats by DEN induction. The EpCAM+ cells were sorted out from unfractionated fetal liver cells and liver cancer cells using the FACS analysis and miRNA expression profiles of two groups were screened through microarray platform. Gain-of-function studies were performed in vitro and in vivo to determine the role of miR-92b on proliferation and differentiation of the hepatic progenitors. In addition, luciferase reporter system and gene function analysis were used to predict miR-92b target. we found that miR-92b was highly downregulated in EpCAM+ fetal liver cells in expression profiling studies. RT-PCR analysis demonstrated reverse correlation between miR-92b expression and differentiation degree in human HCC samples. Overexpression of miR-92b in EpCAM+ fetal liver cells significantly increased proliferation and inhibited differentiation as well as in vitro and in vivo studies. Moreover, we verified that C/EBPß is a direct target of miR-92b and contributes to its effects on proliferation and differentiation. We conclude that aberrant expression of miR-92b can result in proliferation increase and differentiation arrest of hepatic progenitors by targeting C/EBPß.

Tg737 inhibition results in malignant transformation in fetal liver stem/progenitor cells by promoting cell-cycle progression and differentiation arrest.

Cancer stem/progenitor cells (CSPCs) may originate from the malignant transformation of normal stem cells. However, the mechanism by which normal stem cells undergo such transformation is not understood. Our previous studies provided evidence that Tg737 may play an important role in carcinogenesis of liver stem cells. In this study, we investigated the role of Tg737 in the malignant transformation of fetal liver stem/progenitor cells (FLSPCs). We inhibited Tg737 in FLSPCs using short hairpin RNA (shRNA). The microscopic observations of freshly purified Tg737 normal FLSPCs (nFLSPCs) and Tg737‐silent FLSPCs (sFLSPCs), which showed high expression levels of stem cell markers, revealed no significant morphological changes in sFLSPCs. Following RNAi of Tg737, the mRNA and protein levels of sFLSPCs decreased by 81.81% and 80.10% as shown by PCR, Western blot and immunocytochemistry analyses. Excluding apoptosis‐related effects, we found that silencing of Tg737 resulted in enhanced cell proliferation through promoting cell‐cycle progression via upregulation of cyclin D1 and cyclin B expression (P < 0.05). Silencing of Tg737 also resulted in significant arrest of cell differentiation (P < 0.05), stable expression of both albumin (ALB) and alpha fetoprotein (AFP) (P > 0.05) and quiescent ultrastructure. Assessment of cell malignant traits by transwell migration assays and by growth of xenograft tumors in athymic mice showed that reduced expression of Tg737 greatly promoted cell invasion and hepatocarcinogenesis of FLSPCs (P < 0.05). This work shows that inactivation of Tg737 may play an important role in malignant transformation of FLSPCs.

Efficient Enrichment of Hepatic Cancer Stem-Like Cells from a Primary Rat HCC Model via a Density Gradient Centrifugation-Centered Method

Background Because few definitive markers are available for hepatic cancer stem cells (HCSCs), based on physical rather than immunochemical properties, we applied a novel method to enrich HCSCs. Methodology After hepatic tumor cells (HTCs) were first isolated from diethylinitrosamine-induced F344 rat HCC model using percoll discontinuous gradient centrifugation (PDGC) and purified via differential trypsinization and differential attachment (DTDA), they were separated into four fractions using percoll continuous gradient centrifugation (PCGC) and sequentially designated as fractions I–IV (FI–IV). Morphological characteristics, mRNA and protein levels of stem cell markers, proliferative abilities, induced differentiation, in vitro migratory capacities, in vitro chemo-resistant capacities, and in vivo malignant capacities were determined for the cells of each fraction. Findings As the density of cells increased, 22.18%, 11.62%, 4.73% and 61.47% of primary cultured HTCs were segregated in FI–FIV, respectively. The cells from FIII (density between 1.041 and 1.062 g/ml) displayed a higher nuclear-cytoplasmic ratio and fewer organelles and expressed higher levels of stem cell markers (AFP, EpCAM and CD133) than cells from other fractions (P<0.01). Additionally, in vitro, the cells from FIII showed a greater capacity to self-renew, differentiate into mature HTCs, transit across membranes, close scratches, and carry resistance to chemotherapy than did cells from any other fraction; in vivo, injection of only 1×104 cells from FIII could generate tumors not only in subcutaneous tissue but also in the livers of nude mice. Conclusions Through our novel method, HCSC-like cells were successfully enriched in FIII. This study will greatly contribute to two important areas of biological interest: CSC isolation and HCC therapy.