超声空化逆转K562/A02细胞对阿霉素的耐药性研究

Enhancement of Reversing Drug Resistance of K562/A02 Cells to Adriamycin by Ultrasound-induced Cavitation

本研究观察低频低功率超声联合阿霉素(adriamycin,A02)对白血病耐药细胞株K562/A02的影响,寻找合适的干预参数,探讨耐药细胞耐药逆转的可能机制。取对数生长期的白血病K562/A02细胞株,将研究对象分为空白组、单纯阿霉素组(A02)、单纯超声组(US)、阿霉素加超声组(A02+US)共4组。细胞在24孔培养板上受低频低功率超声作用,用台盼蓝拒染法、MTT法检测细胞活性,应用瑞氏染色法和流式细胞术分别检测细胞凋亡和药物浓度,扫描电子显微镜观察细胞表面变化。结果显示,频率20 kHz、声强0.25 W/cm2、作用时间60秒的超声,可显著降低阿霉素的LC50;当声强0.50 W/cm2、作用时间大于30秒的超声,对细胞有急性杀伤作用。细胞经低频超声作用后细胞膜表面出现直径大约1-2μm的小孔,细胞内阿霉素的药物浓度增加,细胞凋亡增强。结论:适当参数的超声辐射通过超声空化导致肿瘤细胞产生声孔效应,使阿霉素对耐药细胞株的抑制作用增强,从而逆转耐药细胞株的耐药性。

This study was aimed to investigate the effects of low frequency and power ultrasound combined with adriamycin on apoptosis of drug-resistant leukemia cell line K562/A02 in vitro, to find out the parameters of optimal exposure, and to explore the possible mechanism reversing drug-resistance of K562/A02 cells. The K562/A02 cells in logarithimic growth phase were used in experiments. The experiments were divided into 4 groups： group control, group adriamycin（A02） alone, group ultrasound（US） alone and group A02 ＋ US. The trypan blue dye exclusion test and MTT assay were used to detemine the cell viability; Wright＇s staining was used to detect the apoptosis; the flow cytometry was used to analyze the drug concentration, and the scanning electron microscopy was used to observe the changes of cell surface. The results showed that the significant differences in cell viability, intracellular adriarnycin coucentration and changes of cell membrane were found between ultrasound-treated and untreated cells in the presence of various concentration of adriamycin. The exposure to ultrasound at 20 kHZ, 0.25 W/cm^2 for 60 seconds could obviously decrease LC50 of adriamycin to K562/A02 cells, while the exposure to ultrasound at 20 kHZ, 0.05 W/cm^2 for 60 seconds could kill K562/ A02 cells at once. After being treated by low frequency ultrasound, the small holes with diameter about 1 -2 μm in the cell surface appeared. The ultrasound increased the adriamycin concentration in the cells, accelerated the formation of apoptotic bodies, and promoted apoptosis of adriamycin-resistant ceils. It is concluded that the ultrasound at optimal param-eters enhances inhibitory effect of adriamycin on drug-resistant cell line, thereby reverses durg-resistance of drug-resistant cell line through sound-hole effect in tumor cells resulting from ultrasound induced cavitation.