Role of calcium ion in the cyotoxicity and DNA fragment induction in HL-60 cells by 6F isolated from Pteris semipinnata L / 中国病理生理杂志

ABSTRACT

AIM: To investigate the changes of cytosolic free calcium concentration ([Ca 2+ ] i) and expression of Bcl-2 in HL-60 cells treated by 6F isolated from Pteris semipinnata L. (PSL), and to discuss the relations between calcium ion and cytotoxicity and DNA fragment induction effects of 6F. METHODS: HL-60 cells were used as in vitro model. [Ca 2+ ] i was measured on fluorescent spectrophotometry using Fura-2/AM as Ca 2+ indicator. Bcl-2 expressing level was measured by flow cytometry. Tetrazolium salt (MTT) and diphenylamine staining methods were applied for cytotoxicity assay and DNA fragmentation detection, respectively. RESULTS: [Ca 2+ ] i increased obviously in a dose and time dependent manner after treated HL-60 cells with 6F. 6F decreased the expressing level of Bcl-2. Adding 2 mmol/L Ca 2+ to the medium, or 1 mmol/L EDTA to chelate Ca 2+ , or 4 ?mol/L calcium ionophore A 23187 to increase the concentration of cytosolic Ca 2+ , the DNA fragment induction by 6F was not affected, whereas the cytotoxicity of 6F was enhanced. 250 ?mol/L Zn 2+ attenuated the DNA fragment induction, and the cytotoxicity of 6F against HL-60 cells was enhanced significantly. CONCLUSION: It was speculated that the decreased expressing of Bcl-2 by compound 6F was related to increased [Ca 2+ ] i in HL-60 cells, and DNA fragment induction was possibly catalyzed by Ca 2+ - independent DNase.