Silver-catalysed three-component reactions of alkynyl aryl ketones, element selenium, and boronic acids leading to 3-organoselenylchromones.

An Ag-catalysed three-component reaction of alkynyl aryl ketones bearing an ortho-methoxy group, element selenium, and arylboronic acid, providing a facile route to selenofunctionalized chromone products has been developed. This protocol features high efficiency and high regioselectivity, and the use of selenium powder as the selenium source. Mechanistic experiments indicated that the combined oxidative effect of (bis(trifluoroacetoxy)iodo)benzene and oxygen in the air pushes the catalytic redox cycle of the Ag catalyst and the phenylselenium trifluoroacetate formed in situ is the key intermediate of the PIFA-mediated 6-endo-electrophilic cyclization and selenofunctionalization reaction of alkynyl aryl ketones.

HBx induces HepG-2 cells autophagy through PI3K/Akt-mTOR pathway.

Chronic hepatitis B virus infection is the dominant global cause of hepatocellular carcinoma (HCC), especially hepatitis B virus-X (HBx) plays a major role in this process. HBx protein promotes cell cycle progression, inactivates negative growth regulators, and binds to and inhibits the expression of p53 tumor suppressor gene and other tumor suppressor genes and senescence-related factors. However, the relationship between HBx and autophagy during the HCC development is poorly known. Previous studies found that autophagy functions as a survival mechanism in liver cancer cells. We suggest that autophagy plays a possible role in the pathogenesis of HBx-induced HCC. The present study showed that HBx transfection brought about an increase in the formation of autophagosomes and autolysosomes. Microtubule-associated protein light chain 3, Beclin 1, and lysosome-associated membrane protein 2a were up-regulated after HBx transfection. HBx-induced increase in the autophagic level was increased by mTOR inhibitor rapamycin and was blocked by treatment with the PI3K-Akt inhibitor LY294002. The same results can also be found in HepG2.2.15 cells. These results suggest that HBx activates the autophagic lysosome pathway in HepG-2 cells through the PI3K-Akt-mTOR pathway.

[Role of autophagy in HepG-2 cells induced by hepatitis B virus x protein].

OBJECTIVE: To investigate the role of autophagy in the injury of HepG-2 cells induced by hepatitis B virus x protein (HBx). METHODS: After HBx transfection, the cells were used to detect the formation of autophagosomes and observed by transmission electron microscopy, monodansylcadaverine (MDC) staining autophagic vacuole (AV), immunofluorescent ce staining microtubule-associated protein light chain 3 ( MAP1-LC3 ) protein, and Western blotting examining the ratio of LC3-II/LC3-I (gray level: 0.760 ± 0.078 vs 0.520 ± 0.086, P < 0.05), beclin 1 (gray level: 0.875 ± 0.093 vs 0.220 ± 0.087, P < 0.05)and lysosome associated membrane protein 2a ( lamp2a ) protein (gray level: 0.320 ± 0.061 vs 0.120 ± 0.064, P < 0.05) levels. RESULTS: (1) HBx transfected upregulated the expression of LC3-II, LC3-I, beclin 1 and lamp2a protein. (2) HBx transfected brought about an increase in the formation of autophagosomes and autolysosomes. CONCLUSION: HBx activates the autophagic lysosome pathway in HepG-2 cells through the LC3/beclin1 pathway.

[Differentiation of polygene-modified bone marrow mesenchymal stem cells into insulin-producing cells].

OBJECTIVE: To evaluate the effects of insulin gene transcription regulators PDX-1, NeuroD1 and MafA on the differentiation of bone marrow mesenchymal stem cells (mMSCs) into insulin-producing cells. METHODS: Murine mMSCs were isolated, cultured and expanded. The base sequences of transcription factors PDX-1, NeuroD1 and MafA were obtained by total gene synthesis and the recombinant adenovirus vectors harboring target genes constructed and transfected into packaging cell line 293A. mMSCs were infected with adenovirus separately or together, and then differentiated in vitro into insulin-producing cells. Reverse transcription-polymerase chain reaction (RT-PCR) was utilized to detect insulin gene expression, immunofluorescence for identifying the presence of insulin protein and insulin enzyme-linked immunosorbent assay (ELISA) for evaluating the secretory volume of insulin. RESULTS: The differentiation extent of mMSCs into ß-cell was analyzed. The ß-cell-specific transcriptional regulators and insulin gene were expressed in mMSCs after transfection. Immunofluorescent analyses revealed the activated expression of insulin in the cytoplasm of differentiated cells. A significant content of insulin was released in these cells in response to a certain concentrations of glucose stimulation. The insulin content of mMSCs infected with a combination of three transcription factors was significantly higher than that of the control group [(112.84 ± 9.67) mU/L vs (1.60 ± 0.22) mU/L, P < 0.05]. CONCLUSION: After modification by transcriptional factors PDX-1, NeuroD1 and MafA, mMSCs can secrete insulin through starting endogenous insulin gene transcription.

Combined transfection of the three transcriptional factors, PDX-1, NeuroD1, and MafA, causes differentiation of bone marrow mesenchymal stem cells into insulin-producing cells.

AIMS: The goal of cell transcription for treatment of diabetes is to generate surrogate ß-cells from an appropriate cell line. However, the induced replacement cells have showed less physiological function in producing insulin compared with normal ß-cells. METHODS: Here, we report a procedure for induction of insulin-producing cells (IPCs) from bone marrow murine mesenchymal stem cells (BM-mMSCs). These BM-mMSCs have the potential to differentiate into insulin-producing cells when a combination of PDX-1 (pancreatic and duodenal homeobox-1), NeuroD1 (neurogenic differentiation-1), and MafA (V-maf musculoaponeurotic fibrosarcoma oncogene homolog A) genes are transfected into them and expressed in these cells. RESULTS: Insulin biosynthesis and secretion were induced in mMSCs into which these three genes have been transfected and expressed. The amount of induced insulin in the mMSCs which have been transfected with the three genes together is significantly higher than in those mMSCs that were only transfected with one or two of these three genes. Transplantation of the transfected cells into mice with streptozotocin-induced diabetes results in insulin expression and the reversal of the glucose challenge. CONCLUSIONS: These findings suggest major implications for cell replacement strategies in generation of surrogate ß-cells for the treatment of diabetes.