Silybin alleviates hepatic lipid accumulation in methionine-choline deficient diet-induced nonalcoholic fatty liver disease in mice via peroxisome proliferator-activated receptor α / 中国天然药物

Nonalcoholic fatty liver disease (NAFLD) is regarded as the most common liver disease with no approved therapeutic drug currently. Silymarin, an extract from the seeds of Silybum marianum, has been used for centuries for the treatment of various liver diseases. Although the hepatoprotective effect of silybin against NAFLD is widely accepted, the underlying mechanism and therapeutic target remain unclear. In this study, NAFLD mice caused by methionine-choline deficient (MCD) diet were orally administrated with silybin to explore the possible mechanism and target. To clarify the contribution of peroxisome proliferator-activated receptor α (PPARα), PPARα antagonist GW6471 was co-administrated with silybin to NAFLD mice. Since silybin was proven as a PPARα partial agonist, the combined effect of silybin with PPARα agonist, fenofibrate, was then evaluated in NAFLD mice. Serum and liver samples were collected to analyze the pharmacological efficacy and expression of PPARα and its targets. As expected, silybin significantly protected mice from MCD-induced NAFLD. Furthermore, silybin reduced lipid accumulation via activating PPARα, inducing the expression of liver cytosolic fatty acid-binding protein, carnitine palmitoyltransferase (Cpt)-1a, Cpt-2, medium chain acyl-CoA dehydrogenase and stearoyl-CoA desaturase-1, and suppressing fatty acid synthase and acetyl-CoA carboxylase α. GW6471 abolished the effect of silybin on PPARα signal and hepatoprotective effect against NAFLD. Moreover, as a partial agonist for PPARα, silybin impaired the powerful lipid-lowering effect of fenofibrate when used together. Taken together, silybin protected mice against NAFLD via activating PPARα to diminish lipid accumulation and it is not suggested to simultaneously take silybin and classical PPARα agonists for NAFLD therapy.

miR-542-3p inhibits the growth and invasion of colorectal cancer cells through targeted regulation of cortactin.

Colorectal cancer is one of the most common malignancies. Previous studies have reported that cortactin (CTTN) is often overexpressed in tumors and is associated with metastasis and poor prognosis of patients. The abnormal expression of microRNAs (miRNAs or miRs) is closely related to the development and progression of various types of cancer, including colorectal cancer. However, little is known about the miRNAs targeting cortactin. In the present study, prediction using biological software revealed that cortactin has binding sites for miR-542-3p. Transfection with miR-542-3p mimic demonstrated that miR­542-3p reduced the expression of cortactin in colorectal cancer cells. Dual luciferase reporter assays further demonstrated that miR-542-3p regulated cortactin in a targeted manner and that miR-542-3p expression was significantly downregulated in colorectal cancer cells. A cell proliferation assay and Transwell migration assay were undertaken: we noted that miR­542-3p inhibited the proliferation and invasion of colorectal cancer cells while promoting their apoptosis. By contrast, cortactin acted antagonistically. When co-transfected with miR-542-3p mimic and CTTN overexpression vector, the inhibitory effect of miR-542-3p was blocked. This indicates that miR-542-3p regulates CTTN in a targeted manner to modulate the growth and invasion of colorectal cancer cells. The present study thus provides new targets for the prevention and treatment of colorectal cancer.

Anti-tumor effect of LTA combined with 5-FU on H22 tumor bearing mice.

OBJECTIVE: To study the effect of lipoteichoic acid (LTA) and 5-FU on the expression of caspase-3, EGFR, TGF-α proteins of tumor tissue of H22 cancer bearing mice and its anti-tumor mechanism. METHODS: A total of 40 SPF grade Kunming mice were selected to establish H22 liver cancer model, and then the mice were divided into 4 groups at random with ten mice in each group. Group A was given saline lavage treatment, Group B was treated with 5-FU by intraperitoneal injection, Group C was treated with LTA by lump body injection; Group D was treated with LTA by lump body injection and 5-FU by intraperitoneal injection. Two weeks after the treatment, the mice in each group were executed and the tumor tissue was stripping and weighted, and the tumor growth inhibition ratio was calculated. Then the tumor tissue was processed for conventional embedding, sectioned to observe the expression of caspase-3, EGFR, TGF-α by immunohistochemical staining method. RESULTS: The tumor inhibitory rate o f Group D was significantly higher than Groups B and C (P < 0.05); B, the tumor inhibitory rate o f Group B had no statistical difference compared with Group C (P > 0.05). The IDO values of TGF-α, EGFR proteins in Groups B, C, D mice tumor tissue were significantly lower than that in group A (P < 0.05); while IDO value of caspase-3 in Groups B, C, D group mice tumor tissue was significantly higher than that in Group A (P < 0.05). The IDO value of TGF-α, EGFR in Group D mice tumor tissue were significantly lower than that in Groups B and C; While IDO value of aspase-3 in Group D was significantly higher than that in Groups B and C (P < 0.05). CONCLUSIONS: LTA combined with 5-FU can effectively inhibit the tumorigenesis of H22 tumor bearing mice, increase the caspase-3 protein expression, inhibit TGF-α and EGFR protein expression, further promote tumor cell apoptosis and play a synergistic antitumor effect.

Hsa-miR-132 inhibits proliferation of hepatic carcinoma cells by targeting YAP.

MicroRNAs and Yes-associated protein (YAP) play an important role in the occurrence and development of hepatic carcinomas. However, the interaction between microRNAs and YAP was seldom elucidated. In this study, we showed that miR-132 could target YAP gene by using dual-luciferase reporter system. Further quantitative polymerase chain reaction analysis and western blotting showed that miR-132 could significantly reduce the expression of YAP at mRNA and protein levels. Results of annexin V-fluorescein isothiocyanate, 5-ethynyl-2'-deoxyuridine staining and transwell assays showed that miR-132 significantly promoted the cell apoptosis and effectively inhibited the proliferation and invasion of hepatoma cells. These results indicated that miR-132 could inhibit the growth of hepatoma cells by targeting YAP gene and reducing its expression level. Taken together, results from this study would help us to understand the mechanisms for occurrence and development of hepatic carcinoma and provide new targets for diagnosis and treatment of liver cancer.

Lentivirus vectors construction of SiRNA targeting interference GPC3 gene and its biological effects on liver cancer cell lines Huh-7.

OBJECTIVES: To build GPC3 gene short hairpin interference RNA (shRNA) slow virus vector, observe expression of Huh-7 GPC3 gene in human liver cell line proliferation apoptosis and the effect of GPC3 gene influencing on liver cancer cell growth, and provide theoretical basis for gene therapy of liver cancer. METHODS: Hepatocellular carcinoma cell line Huh-7 was transfected by a RNA interference technique. GPC3 gene expression in a variety of liver cancer cell lines was detected by fluorescence quantitative PCR. Targeted GPC3 gene sequences of small interfering RNA (siRNA) PGC-shRNA-GPC3 were restructured. Stable expression cell lines of siRNA were screened and established with the help of liposomes (lipofectamine(TM2000)) as carrier transfection of human liver cell lines. In order to validate siRNA interference efficiency, GPC3 siRNA mRNA expression was detected after transfection by using RT-PCR and Western blot. The absorbance value of the cells of blank group, untransfection group and transfection group, the cell cycle and cell apoptosis were calculated, and effects of GPC3 gene on Huh-7 cell proliferation and apoptosis were observed. RESULTS: In the liver cancer cell lines Huh-7, GPC3 gene showed high expression. PGC-shRNA-GPC3 recombinant plasmid was constructed successfully via sequencing validation. Stable recombinant plasmid transfected into liver cancer cell lines Huh-7 can obviously inhibit GPC3 mRNA expression level. CONCLUSIONS: The targeted GPC3 siRNA can effectively inhibit the expression of GPC3.