Design, synthesis and evaluation of novel bis-substituted aromatic amide dithiocarbamate derivatives as colchicine site tubulin polymerization inhibitors with potent anticancer activities.

As the continuation of our work on the development of tubulin inhibitors with potential anticancer activities, novel bis-substituted aromatic amide dithiocarbamate derivatives were designed by contacting bis-substituted aryl scaffolds (potential anti-tubulin fragments) with N-containing heterocycles (potential anti-tubulin fragments) in one hybrid using the anticancer dithioformate unit as the linker. The antiproliferative activity against three digestive tract tumor cells was evaluated and preliminary structure activity relationships were summarized. Among these compounds, compound 20q exhibited most potent antiproliferative activity against MGC-803, HCT-116, Kyse30 and Kyse450 cells with IC50 values of 0.084, 0.227, 0.069 and 0.078 µM, respectively. In further studies, compound 20q was identified as a novel tubulin inhibitor targeting the colchicine binding site. Compound 20q could inhibit the microtubule assembly and disrupt cytoskeleton in Kyse30 and Kyse450 cells. The results of molecular docking suggested that compound 20q could tightly bind into the colchicine binding site of tubulin by hydrogen bonds and hydrophobic interactions. Compound 20q dose-dependently inhibited the cell growth and colony formation, effectively arrested cells at the G2/M phase and induce mitochondrial apoptosis in Kyse30 and Kyse450 cells. In addition, Compound 20q could regulate the expression of G2/M phase and mitochondrial apoptosis related proteins. Collectively, compound 20q was here reported as a novel tubulin inhibitor with potential anticancer activities.

Luteolin inhibits cell proliferation and induces cell apoptosis via down-regulation of mitochondrial membrane potential in esophageal carcinoma cells EC1 and KYSE450.

In current study, we investigated the anti-tumor effect of luteolin in human ESCC cell lines in vitro and in vivo and tried to explore the potential mechanisms. Results from flow cytometry showed that luteolin could induce apoptosis and caspase-3 activation and induce cell cycle arrest at G2/M phase in a dose- and time-dependent manner in EC1 and KYSE450 cells. JC-1 test results showed that membrane potential of mitochondria after luteolin treatment was down-regulated and this was an indicator for intrinsic apoptosis. Western Blot results showed the expression of cell cycle regulatory protein p21 and p53 increased and three apoptosis related proteins that participate in mitochondrial apoptotic pathway, namely, Bim, CYT-c and cPARP, also increased in luteolin treated cells compared with control groups. We further confirmed that luteolin could significantly inhibit the growth of ESCC tumors in xenograft mouse models and no evidence of systemic toxicity was observed. Our results suggest that luteolin can induce cell apoptosis and cell cycle arrest in G2/M phase through mitochondrial pathway in EC1 and KYSE450 cell lines and proper utilization of luteolin might be a practical approach in ESCC chemotherapy.

Capillary electrophoresis coupled with electrochemical detection using porous etched joint for determination of antioxidants.

Capillary electrophoresis coupled with electrochemical detection (CE-EC) for determination of antioxidants, propyl gallate (PG) and tert-butylhydroquinone (TBHQ), in cosmetic samples was proposed in this work. A porous etched joint was used to isolate the electrochemical detection from the electrophoretic high voltage. Compared with the 25 microm i.d. capillary without a decoupler in a CE-EC system, a 75 microm i.d. capillary applied in the present system gave an improvement in both sample injection and sensitivity. Moreover, the carbon fiber working electrode could be directly in touch with the end of separation capillary due to the elimination of the effect of separation voltage on the EC detection, so the alignment of working electrode and capillary became easy and the dead volume was also decreased. Baseline separation of the two antioxidants was achieved by CE in a 50 cm long x 75 microm i.d. capillary at 20 kV using 5.0 mmol L(-1) phosphate buffer (pH 8.00). 0.7 V (versus Ag/AgCl) was applied to the carbon fiber electrode for electrochemical detection. Under the optimal condition, the precisions (RSD, n=4) of peak height and migration time of PG and TBHQ were 2.39-3.59% and 0.34-0.44%, respectively. The detection limits of PG and TBHQ were 2.51x10(-6) and 4.88 x 10(-6) mol L(-1) for standard solution and 0.0751 and 0.0328 mg g(-1) for the real cosmetic samples with consumption of 0.3g sample. Analysis of TBHQ and PG in cosmetics samples was also achieved with the present system and the spiked recoveries of two analytes in cosmetics samples were in the range of 93.6-98.8%.