[Triptolide increases the radiosensitivity of lung cancer cells by inhibiting DNA repair and inducing apoptosis]

Objective: To investigate the effect of triptolide on radiosensitivity of lung cancer cells and its mechanism. Methods: The lung cancer cells H1299, A549, H157 and H838 were cultured. The strongest radio resistance cell line, H1299 was selected by cell clone formation experiment and for the subsequent experiments. 3-(4, 5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2H tetrazolium bromide (MTT) was used to detect the effect of different concentrations of triptolide on the proliferation of H1299 cells. The optimal concentration of triptolide was 50nmol/L, and the optimal treatment time was 48 hours. The H1299 cells were divided into the control group, triptolide group (50 nmol/L), 4 Gy group and triptolide+ 4 Gy group. Flow cytometry was used to detect the apoptosis rate of H1299 cell. Western Blot was used to detect the proteins expression levels of p-Chk2, p-ATM, p-p53, Bcl-2, Bax and cleaved-Caspase 3. Results: The apoptotic rate and protein levels of Bax, cleaved-Caspase 3, p-Chk2, p-ATM and p-p53 in the 4 Gy group were (12.38±1.34)%, 0.42±0.04, 0.38±0.04, 0.98±0.11, 0.73±0.08, 0.95±0.09, respectively, higher than (3.26±2.43)%, 0.22±0.02, 0.23±0.03, 0.32±0.03, 0.21±0.02, 0.25±0.03 in the control group (P<0.05). However, the protein level of Bcl-2 was (0.52±0.05), lower than (0.93±0.09) of the control group (P<0.05). The survival fraction (0.462) and protein level of Bcl-2 (0.44±0.04) in the triptolide group were lower than those of the control group (0.702 and 0.93±0.09, P<0.05). The apoptotic rate and the protein levels of Bax and cleaved-Caspase 3 in the triptolide group were (9.27±1.08)%, 0.45±0.05, 0.41±0.04, respectively, higher than (3.26±2.43)%, 0.22±0.02, 0.23±0.03 in the control group (P<0.05), and the sensitization ratio in the triptolide group was 1.579. The apoptosis rate, Bax and cleaved Caspase 3 protein expression levels in triptolide + 4 Gy group were (26.53±2.19)%, 0.91±0.09 and 0.79±0.08, respectively, higher than (12.38±1.34)%, 0.42±0.04 and 0.38±0.04 in 4 Gy group (P<0.05). The expression level of Bcl-2 protein was (0.21±0.02), lower than (0.52±0.05) in 4 Gy group (P<0.05). Conclusion: Triptolide increases the radiosensitivity of radiation-induced lung cancer cells by inhibiting DNA repair and inducing apoptosis.

[Isolation of a kind of endophytic fungus which can produce taxol compounds]

OBJECTIVE

To isolate a kind of endophytic fungus which can produce taxol compounds from the bark of Taxus Cuspidata Sieb et Zucc.

METHODS

Endophytic fungus was isolated from the bark of Taxus Cuspidata Sieb et Zucc by aseptic techniques and the analysis of the culture fluid from the fermentation of fungus was carried out by high performance liquid chromatography (HPLC).

RESULTS

Endophytic fungus was obtained from the bark of Taxus Cuspidata Sieb et Zucc and the chemical analysis showed that the culture of fungus contain taxol compounds.

CONCLUSION

Endophytic fungus which can produce taxol compounds exists in the bark of Taxus Cuspidata Sieb et Zucc.

[Component analysis of the extracellular polysaccharide from Mortierella hepiali Chen et Lu sp. nov]

The extracellular polysaccharide from the filtrate of fungal fermentation of Mortierella hepiali, a fungus isolated from traditional Chinese crude drug Cordyceps sinesis, is made up of three sugar components, glucose, mannose and galactose, which are detected by paper and gas chromatography. Both molar ratio and contents of the polysaccharide are determined by the internal standard method.