Thapsigargin逆转K562/A02细胞多药耐药性的实验研究

目的 探讨内质网Ca^2 -ATP酶抑制剂thapsigargin对白血病多药耐药细胞株K562／A02化疗敏感性的影响。方法 用MTT比色法检测K562／A02细胞耐药性、thapsigargin的增殖抑制活性及其对K562／A02细胞化疗敏感性的影响；丫啶橙(AO)／溴化乙锭(EB)染色荧光显微镜观察thapsigargin处理后K562／A02细胞形态改变；流式细胞仪(FCM)检测P-糖蛋白(P-gp)表达；荧光显微镜检测Pgp功能。结果 ①thapsigargin对K562和K562／A02细胞的增殖抑制活性呈剂量和时间依赖性，K562／A02细胞较K562细胞对thapsigargin更敏感，thapsigargin诱导K562／A02细胞呈现典型的凋亡细胞形态学改变。②K562／A02细胞对阿霉素(ADM)、柔红霉素(DNR)、长春新碱(VCR)、依托泊苷(VP-16)、高三尖杉酯碱(HHT)和米托蒽醌(MXT)均出现不同程度的耐药性；thapsigargin抑制K562／A02细胞P-gP功能而对其表达无影响，thapsigargin能增加K562／A02细胞对ADM、DNR、VCR、VP-16、HHT和MXT的化疗敏感性。结论 Thapsigargin能诱导白血病多药耐药细胞株K562／A02细胞凋亡并能部分逆转K562／A02的多药耐药性；thapsigargin的多药耐药逆转功能可能与其凋亡诱导作用和抑制PgP功能有关。

Reversal of Multidrug Resistance by Thapsigargin in K562/A02 Cells

Objective To study the effect of thapsigargin on chemotherapeutic sensitivity in multidrug-resistant leukemia cell line K562/A02 induced by ADM.Methods Multidrug resistance of K562/A02 cells,the cell-proliferating inhibitory activity of thapsigargin and the effect of thapsigargin on chemotherapeutic sensitivity were assessed by using MTT assay. Morphological change of K562/A02 cells treated with thapsigargin was examined with AO/EB fluorescent staining under fluorescent microscopy. The P-gp expression of K562/A02 cells was detected by flow cytometry and P-gp function was evaluated with adriamycin (ADM),daunorubicin (DNR) and Rh123 accumulation in K562/A02 cells by fluorescent microscopy.Results Thapdigargin inhibited the proliferation of K562/A02 cells in a dose- and time-dependent manner. K562/A02 cells were more sensitive to thapsigargin than their parent K562 cells. Thapsigargin induced typical apoptosis of K562/A02 cells showed by typical apoptotic morphological changes. K562/A02 cells were resistant to ADM,DNR,vincristine (VCR),etoposide (VP-16),homoharringtonine (HHT) and mitoxantrone (MXT) to varying degrees. Thapsigargin significantly inhibited P-gp function of K562/A02 cells,but not the P-gp expression,and enhanced the chemotherapeutic sensitivity of K562/A02 cells to above conventional chemotherapeutic agents.Conclusion Thapsigargin induces growth inhibition and apoptosis of multidrug-resistant leukemia cell line K562/A02 and partially reverse the resistance of the cells to conventional chemotherapeutic agents. The reversal action of thapsigargin can be associated with apoptosis-induced effect and inhibition of P-gp function.