TNF-alpha induced reversal of multidrug resistance in human hepatocellular carcinoma cells / 中华外科杂志

<p><b>OBJECTIVE</b>To investigate the reversal of multidrug resistance in the cell line HepG2/ADM induced by TNF-alpha.</p><p><b>METHODS</b>HepG2/ADM cells were incubated with different concentrations of TNF-alpha (100, 500 and 2500 U/ml) for 72 h. Real-time PCR was performed to compare the mRNA levels of MDR1 with PPAR-alpha in the different concentrations of TNF-alpha treated cells. The Annexin V assay was used to check cell apoptosis induced by 0.5 mg/L adriamycin. Rhodamine 123 efflux assay and MTT assay were used to study P-gp activity and drug resistance in each group, respectively.</p><p><b>RESULTS</b>TNF-alpha could induce down-regulation of MDR1 and up-regulation of PPAR-alpha. Meanwhile, it could enhance cell cytotoxicity and cell apoptosis induced by 0.5 mg/L adriamycin.</p><p><b>CONCLUSIONS</b>TNF-alpha could partially reverse the multidrug resistance of HepG2/ADM cells by down-regulating the expression of MDR1 and up-regulating the expression of PPAR-alpha.</p>

Expressions of ATP binding cassette transporter genes in rat hepatic oval cells / 中华肝脏病杂志

<p><b>OBJECTIVE</b>Liver regeneration occurs through hepatocytes after acute liver injury. However, severe liver injury activates bipotential oval cells from canals of Hering which can differentiate into hepatocytes and biliary epithelial cells. Most models of oval cell activation have employed potential carcinogens to inhibit hepatocyte replication in the face of a regenerative stimulus. Oval cells must be able to withstand the toxic milieu of the damaged liver. ATP binding cassette transporters are cytoprotective efflux pumps that may contribute to the protection of these cells. The aim of this study was to determine the ABC transporter expressions in hepatic oval cells.</p><p><b>METHODS</b>A rat model was established by feeding 2-acetylaminofluorene combined with partial hepatectomy to activate hepatic oval cells. Oval cells were isolated and purified using selective enzymatic digestion and density gradient centrifugation from the heterogeneous hepatic cell population. The expressions of ABC transporter gene, including MDR1, MRP1 and Bcrp1, in isolated hepatic oval cells and hepatocytes were measured by quantitative real-time reverse transcription-polymerase chain reaction and those in rat liver tissues were measured by immunohistochemistry.</p><p><b>RESULTS</b>Compared to those in the rat hepatocytes, mRNA expressions of the genes encoding MDR1, MRP1 and Bcrp1 were increased up to 9-, 1.5- and 13.8-folds in hepatic oval cells. Immunohistochemical staining of rat liver slides demonstrated that the expression of MDR1 proteins was found around periportal areas, and Bcrp1 protein was found located on cell membranes.</p><p><b>CONCLUSION</b>Hepatic oval cells express high levels of the ABC transporter gene that may have cytoprotective functions during severe hepatotoxicity.</p>

Expression of Twist gene in human hepatocellular carcinoma and its clinicopathological significance / 中华外科杂志

<p><b>OBJECTIVE</b>To investigate the expression and clinicopathological significance of transcription factor Twist in hepatocellular carcinoma (HCC), paraneoplastic and cirrhotic tissues.</p><p><b>METHOD</b>Immunohistochemistry was used to detect the expression of the Twist protein in 26 cases of HCC and paraneoplastic tissue and 10 cases of cirrhotic tissue. Meanwhile, the Twist mRNA and its protein were detected in 10 HCC tissues and 10 paraneoplastic tissues by RT-PCR and Western blot. And the expression differences and clinicopathological significances of the expression of Twist gene and its protein were analyzed.</p><p><b>RESULTS</b>The positive rates of the Twist protein in HCC, paraneoplastic and cirrhotic tissues were 84.6%, 19.2 % and 20.0 %, respectively. The positive rate of Twist in HCC was higher than that in paraneoplastic or cirrhosis tissues (P < 0.05). Compared with in paraneoplastic tissues, the mRNA and protein expression of Twist were up-regulated in HCC by 2.52 and 2.13 times, respectively.</p><p><b>CONCLUSION</b>Twist has an inappropriate expression in hepatocellular carcinoma and it may play an important role in the tumorigenesis and progression of HCC.</p>

Migration of dendritic cells in orthotopic rat liver transplantation / 中华器官移植杂志

Objective To investigate migration of dendritic cells(DC)in orthotopic rat liver transplantation models.Methods Allogeneic models(Wistar→SD,experimental group)and syngenic models(Wistar→Wistar,control group)of rat liver transplantation were established.Graft livers and host celiac lymph nodes(n=4)of each group were sampled respectively at day 3,5,and 7 after the transplantation.The acute rejection was graded according to liver histopathological changes.The dy- namic state of DC number within graft and lymph nodes was detected by means of immunohistochemi- cal staining and image analysis.T-cell active proliferative response in lymph nodes was also studied. Results The histological examination revealed that mild to severe rejection occurred on the post-opera- tive days 5 and 7.At day 3 after transplantation,the number of S-100~+ DC in allograft was signifi- cantly increased and reached the peak at day 5,then decreased gradually at day 7.A significant num- ber of S-100~+ cells was detected in the allogeneic host lymph nodes from day 3 after transplantation, and displayed a continuous increasing trend for next several days.Active proliferation of T cells in the lymph nodes was triggered as early as day 3 after transplantation.Conclusion Allogeneic liver trans- plantation induces the accelerated migration of DC within the allograft and host lymphoid nodes.DC delivers a strong and sustained stimulation among T cells in the lymphoid nodes where effector cells are predominantly sensitized and rejected the graft eventually.