The nuclear receptor farnesoid X receptor (FXR) acts as a liver protector by regulating normal liver homeostasis. Spontaneously developed liver tumors have been found in FXR-null mice. However, the role of FXR in the tumorigenesis of human hepatocellular carcinoma (HCC) is still poorly understood. In this study, we measured the expression of FXR and its primary target gene, small heterodimer partner, and analyzed the clinical significance of FXR expression in HCC patients. A lentiviral vector that selectively overexpresses FXR was used to investigate the function of FXR in HCC cell proliferation both in vitro and in vivo. Our data showed that in human HCC, FXR expression was significantly reduced and was positively correlated with multiple malignant clinicopathological characteristics. Lentivirus-mediated exogenous FXR expression resulted in a marked increase of small heterodimer partner expression, significant repression of liver cancer cell proliferation, and tumor growth in nude mice. These results suggest that FXR may be of clinical and pharmacological importance as a promising biomarker of HCC. farnesoid X receptor; small heterodimer partner; tumor suppressor; proliferation HUMAN HEPATOCELLULAR CARCINOMA (HCC) is one of the most common human malignancies in the world and is prevalent in developing countries. In China, HCC has become the second highest cancer-related cause of death since the 1990s and accounts for 53% of all liver cancer deaths worldwide (12). The high mortality of HCC is due in large part to the lack of good biomarkers for early diagnosis and treatment assessment. Patients are often diagnosed at advanced stages, when most available therapies have only limited efficacy.The farnesoid X receptor (FXR) is a member of the nuclear receptor superfamily of ligand-activated transcription factors and is highly expressed in the liver. FXR controls the expression of various genes involved in bile acid, lipid, and glucose metabolism (21). In recent years, the understanding of the role of FXR in the liver has developed from that as a metabolic regulator to the novel function as a cell protector implicated in liver regeneration (9, 23) and hepatocarcinogenesis (22). In 2007, we first reported that in the absence of FXR, mice displayed spontaneous development of liver tumors (22). In parallel, Kim et al. (10) published very similar observations showing that aged FXR-null mice had a high incidence of liver tumors. However, limited information was available regarding the role of FXR in the development and progression of human HCC.The nuclear receptor small heterodimer partner (SHP) is an important modulator of metabolic signaling pathways (1,8,20) and is a primary FXR target gene. One of the well-characterized mechanisms by which FXR regulates gene expression in the liver is through the induction of SHP. Recent studies (24, 25) have revealed the role of SHP in the inhibition of cellular proliferation. However, combined loss of FXR and SHP expression in human HCC has not been previously reported.In this study...

Altered expression of miRNAs may contribute to multidrug resistance (MDR) in human cancers. This study investigated the association between miRNAs and MDR in five different drug-resistant hepatocellular carcinoma (HCC) cell sublines. The HCC Huh-7 cell line was treated with adramycin (ADM), cisplatin (DDP), carboplatin (CBP), mitomycin C (MMC) or vincristine (VCR) at increasing concentrations to develop drug-resistant sublines. The cell viability MTT assay was used to detect drug resistance. Five different drug-resistant HCC sublines, Huh-7/ADM, Huh-7/CBP, Huh-7/DDP, Huh-7/MMC and Huh-7/VCR, were established. Cells that were resistant to one drug were also found to be resistant to the other drugs. miRNA microarrays were analyzed to identify differential miRNA expression profiles in these cell lines, and real-time PCR was used to validate miRNA microarray data. miRNA microarray analysis showed that there were 53 upregulated miRNAs in Huh-7/ADM, 56 in Huh-7/CBP, 58 in Huh-7/DDP, 58 in Huh-7/MMC and 49 in Huh-7/VCR, whereas there were 52 downregulated miRNAs in Huh-7/ADM, 50 in Huh-7/CBP, 41 in Huh-7/DDP, 55 in Huh-7/MMC and 56 in Huh-7/VCR. Moreover, 26 simultaneously upregulated and 25 simultaneously downregulated miRNAs were noted in the Huh-7/ADM, Huh-7/CBP, Huh-7/DDP and Huh-7/MMC sublines compared to the parental Huh-7 cell line. In contrast, among these 51 upregulated and downregulated miRNAs, 12 miRNAs were upregulated and 13 miRNAs were downregulated in Huh-7/VCR. Upregulation of miR-27b, miR-181a, miR-146b-5p, miR-181d and miR-146a expression was verified using real-time RT-PCR in the parental and the five drug-resistant cell lines. In conclusion, the present study demonstrates that the differentially expressed miRNA profiles in these five drug-resistant HCC sublines could be useful to further investigate the association of miRNA expression with drug resistance in HCC.

IntroductionThe effect of intra-articular injection of matrix metalloproteinase (MMP)-3 inhibitor was investigated in a rat model to understand the role of MMP-3 in cartilage degradation induced by excessive loading from running.MethodsA total of 24 male Wistar rats were randomly assigned into groups of sedentary control (SED), high-intensity running (HIR), HIR + low dosage of MMP-3 Inhibitor I (HIRI1), and HIR + high dosage of MMP-3 Inhibitor I (HIRI2). Rats in the HIR, HIRI1 and HIRI2 groups were intensively trained for six weeks on the treadmill. Those in HIRI1 and HIRI2 groups were provided bilateral intra-articular injections of 80 μL of 0.2 mM and 2 mM MMP-3 Inhibitor I in knee joints once a week, respectively. Blood samples were collected to measure serum MMP-3 level using ELISA. Femoral condyles were collected to observe cartilage characteristics by histochemistry, and MMP-3 as well as collagen II was measured by immunohistochemistry. In addition, cartilage samples were obtained to assess MMP-3 mRNA expression by RT-PCR.ResultsHistological examination showed osteoarthritic changes in rats after six weeks of high intensity running. In comparison to the SED group, significant decreases in glycosaminoglycans (GAG) and collagen content were found in the HIR group, which corresponded to significant increase in serum MMP-3 level, cartilage MMP-3 activity and gene expression. However, such a degradative process was considerably retarded by intra-articular injection of MMP-3 inhibitor at higher dosage. Statistical differences were found between the HIR and HIRI2 groups with regard to GAG and collagen II content, serum MMP-3 level, cartilage MMP-3 activity and gene expression.ConclusionsHigh-intensity running for six weeks may lead to cartilage degradation in a rat model. It was shown that the chrondroprotective effect was offered by the use of intra-articular injection of MMP-3 inhibitor. MMP-3 acts as the key mediator of this catabolic change under such mechanical condition. The results also showed that MMP-3 selective inhibitor may be an effective option for retarding such osteoarthritic changes.

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