Subergorgic acid is one of marine neurotoxins. It has a unique chemical structure. This article reviews its isolation and structural determination, total synthesis,derivatives preparation,biologic activities and potential applications.

OBJECTIVETo investigate the effect of Nrf2 gene knockdown on hirsutanols A-induced cytotoxicity in cancer cells.

METHODSThe changes in the cell viability following treatment with different concentrations of hirsutanols A was detected by MTT assay, and the generation of reactive oxygen species (ROS) was assayed using flow cytometry. AnnexinV-FITC apoptosis kit was used to detect the cell apoptosis. Nrf2 protein expression in HepG2 and SW480 cells transfected with the siRNA targeting Nrf2 was analyzed with Western blotting.

RESULTSAt the concentrations of 1.25, 2.5, 5, 10, 20 and 40 µmol/L, hirsutanols A obviously inhibited the cell proliferation of human liver cancer HepG2 and colon cancer SW480 cells in a concentration-dependent manner. The levels of hydrogen peroxide increased rapidly after hirsutanols A treatment in both HepG2 (30 µmol/L) and SW480 (15 µmol/L) cells. Hirsutanols A also induced apoptosis of the two cells. Pretreatment with 5 mmol/L NAC totally inhibited apoptosis and ROS accumulation in the two cells induced by hirsutanols A. Transfection of HepG2 and SW480 cells with the siRNA caused a significant reduction in Nrf2 protein expression, which resulted in an increased sensitivity of the cells to hirsutanols A.

CONCLUSIONHirsutanols A can induce apoptosis in HepG2 and SW480 cells by promoting ROS production and up-regulating Nrf2 expression. Nrf2 knockdown by siRNA can increase the sensitivity of the cancer cells to hirsutanols A in vitro.

Apoptosis ; drug effects ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Colonic Neoplasms ; metabolism ; pathology ; Gene Expression Regulation, Neoplastic ; Gene Knockdown Techniques ; Humans ; Liver Neoplasms ; metabolism ; pathology ; NF-E2-Related Factor 2 ; genetics ; RNA, Small Interfering ; Reactive Oxygen Species ; metabolism ; Sesquiterpenes ; pharmacology

To enhance biohydrogen production of Klebsiella sp. HQ-3, the global transcriptional factor (Fnr), formate dehydrogenase H (FDH1) and the pncB gene encoding the nicotinic acid phosphoribosyltransferase (NAPRTase) were for the first time over-expressed in Klebsiella sp. HQ-3. The fnr, fdhF, pncB genes were cloned from the genomic DNA of Klebsiella sp. HQ-3 by 3 pairs of universal primers, and introduced into the corresponding sites of the modified pET28a-Pkan, resulting in the plasmids pET28a-Pkan-fnr, pET28a-Pkan-fdhF and pET28a-Pkan-pncB. The 4 plasmids were then electroported into wild Klebsiella sp. HQ-3 to create HQ-3-fnr, HQ-3-fdhF, HQ-3-pncB and HQ-3-C, respectively. Hydrogen production was measured using a gas chromatograph and the metabolites were analyzed with a high-performance liquid chromatograph (HPLC). The results indicate that over-expression of fnr, fdhF and pncB significantly enhanced hydrogen production in the three recombinant strains. Hydrogen production per mol glucose for HQ-3 fnr, HQ-3 pncB, HQ-3 fdhF was 1.113, 1.106 and 1.063 mol of hydrogen/mol glucose, which was respectively increased by 12.26%, 11.62% and 7.28% compared with that of the control strain HQ-3-C (0.991 mol of hydrogen/mol glucose). Moreover, the analysis of HPLC showed that the concentrations of formate and lactate were markedly decreased, but succinate remained unchanged in culture media compared with those of the control strain HQ-3-C.
Fermentation ; Formate Dehydrogenases ; biosynthesis ; genetics ; Hydrogen ; metabolism ; Iron-Sulfur Proteins ; biosynthesis ; genetics ; Klebsiella ; genetics ; metabolism ; Metabolic Engineering ; methods ; Metabolic Networks and Pathways ; Pentosyltransferases ; biosynthesis ; genetics