Isobavachalcone induces cell death through multiple pathways in human breast cancer MCF-7 cells / 南方医科大学学报

OBJECTIVE@#To explore the effects of isobavachalcone (IBC) on cell death of human breast cancer MCF-7 cells and explore the possible mechanism.@*METHODS@#MCF-7 cells were treated with different concentrations of IBC, and the changes in cell proliferation were assessed using MTT assay. Apoptosis of MCF-7 cells following treatment with 10, 20, and 40 μmol/L IBC was analyzed using flow cytometry with annexin V-FITC/PI double staining and fluorescence microscopy, and the expressions of apoptosis- and autophagy-related proteins (Bax, Bcl-2, Akt, p-Akt, p62, and LC3) were detected with Western blotting. Electron microscopy was used to observe the changes in submicrostructure of the cells following treatment with 40 μmol/L IBC. JC-1 assay kit, ATP assay kit, and reactive oxygen species (ROS) kit were used to determine the effect of IBC on mitochondrial function of the cells.@*RESULTS@#MTT assay showed that IBC significantly inhibited the proliferation of MCF-7 cells in a concentration- and time-dependent manner, with IC50 values of 38.46, 31.31, and 28.26 μmol/L at 24, 48, and 72 h, respectively. IBC also concentration-dependently induced apoptosis of MCF-7 cells. IBC-induced cell death was inhibited by z-VAD-fmk, a caspase inhibitor (P < 0.05), but not by the necroptosis inhibitor necrostatin-1 (Nec-1). Western blotting showed that IBC-induced MCF-7 cell apoptosis by increasing Bax expression and down-regulating the expressions of Bcl-2, Akt and p-Akt-473 (all P < 0.05). With the increase of IBC concentration, the expression of autophagy-related protein p62 and the LC3-II/I ratio increased progressively. Electron microscopy revealed the presence of autophagic bodies in IBC-treated MCF-7 cells. IBC treatment also resulted in decreased mitochondrial membrane potential and intracellular ATP level and increased ROS accumulation in MCF-7 cells (P < 0.05).@*CONCLUSION@#IBC is capable of inducing both apoptosis and autophagy in MCF-7 cells, suggesting the potential value of IBC as a lead compound in the development of anti-breast cancer agents.

Enzymatic biosynthesis of novel neobavaisoflavone glucosides via Bacillus UDP-glycosyltransferase / 中国天然药物

The present study was designed to perform structural modifications of of neobavaisoflavone (NBIF), using an in vitro enzymatic glycosylation reaction, in order to improve its water-solubility. Two novel glucosides of NBIF were obtained from an enzymatic glycosylation by UDP-glycosyltransferase. The glycosylated products were elucidated by LC-MS, HR-ESI-MS, and NMR analysis. The HPLC peaks were integrated and the concentrations in sample solutions were calculated. The MTT assay was used to detect the cytotoxic activity of compounds in cancer cell lines. Based on the spectroscopic analyses, the two novel glucosides were identified as neobavaisoflavone-4'-O-β-D-glucopyranoside (1) and neobavaisoflavone-4', 7-di-O-β-D-glucopyranoside (2). Additionally, the water-solubilities of compounds 1 and 2 were approximately 175.1- and 4 031.9-fold higher than that of the substrate, respectively. Among the test compounds, only NBIF exhibited weak cytotoxicity against four human cancer cell lines, with IC values ranging from 63.47 to 72.81 µmol·L. These results suggest that in vitro enzymatic glycosylation is a powerful approach to structural modification, improving water-solubility.

Biosynthesis of a new psoralidin glucoside by enzymatic glycosylation / 南方医科大学学报

<p><b>OBJECTIVE</b>To modify the structure of psoralidin using in vitro enzymatic glycosylation to improve its water solubility and stability.</p><p><b>METHODS</b>A new psoralidin glucoside (1) was obtained by enzymatic glycosylation using a UDP- glycosyltransferase. The chemical structure of compound 1 was elucidated by HR-ESI-MS and nuclear magnetic resonance (NMR) analysis. The high-performance liquid chromatography (HPLC) peaks were integrated and sample solution concentrations were calculated. MTT assay was used to detect the cytotoxicity of the compounds against 3 cancer cell lines in vitro. Results Based on the spectroscopic data, the new psoralidin glucoside was identified as psoralidin-6',7-di-O-β-D- glucopyranoside (1), whose water solubility was 32.6-fold higher than that of the substrate. Analyses of pH and temperature stability demonstrated that compound 1 was more stable than psoralidin at pH 8.8 and at high temperatures. Only psoralidin exhibited a moderate cytotoxicity against 3 human cancer cell lines. Conclusion In vitro enzymatic glycosylation is a powerful approach for structural modification and improving water solubility and stability of compounds.</p>

Chemical modification endows heparin with low anticoagulant and high antineoplastic activities / 南方医科大学学报

<p><b>OBJECTIVE</b>To evaluate the anticoagulant and antineoplastic activities of chemically modified low-molecular-weight heparin (LMWH).</p><p><b>METHODS</b>LMWH obtained by splitting unfractionated heparin (UFH) with sodium periodate oxidation and sodium borohydride reduction was subjected to acetylation catalyzed by DCC and DMAP to produce acetylated LMWH (ALMWH). The anticoagulant activity of ALMWH was determined in mice, and its antiproliferative and anti-invasion activities was assessed in human breast cancer cells MDA-MB-231 and MFC-7.</p><p><b>RESULTS</b>The anticoagulant activity of LMWH was decreased significantly after acetylation. The concentrations of commercial LMWH* and ALMWH for doubling the coagulation time (CT) were 33.04 µmol/L and 223.56 µmol/L, respectively, and the IC(50) of ALMWH for doubling CT was 6 times of that of LMWH*. ALMWH and LMWH at 0.1, 0.3, 0.9, 2.7 and 8.1 mmol/L both significantly inhibited the proliferation of MDA-MB-231 and MCF-7 cells in a concentration-dependent manner, but ALMWH produced stronger inhibitory effects. The IC(50) of LMWH and ALMWH for inhibiting cell proliferation was 3168.4 µmol/L and 152.6 µmol/L in MCF-7 cells, and 12299.6 µmol/L and 22.2 µmol/L in MDA-MB-231 cells, respectively. ALMWH and LMWH all markedly suppressed the invasion of MDA-MB-231 cells with comparable effects.</p><p><b>CONCLUSION</b>Chemical modification of structure can endow LMWH with a low anticoagulant and high antiproliferative activities.</p>