白血病K562／ADM细胞耐药性与白血病干细胞及耐药蛋白表达的关系

The relationship between multi-drug resistance and proportion of leukemia stem cells and expression of drug transporters in drug-resistant leukemia K562/ADM cells

目的观察白血病药物敏感和耐受细胞中自血病干细胞（LSC）、耐药蛋白表达和耐药性的关系。方法以白血病多药耐药株K562／ADM细胞及其亲本K562细胞为模型，MTT比色法测定细胞的药物耐受性；流式细胞术检测细胞免疫标志、P-糖蛋白（P—gP）和乳腺癌耐药蛋白（BCRP）的表达；甲基纤维素集落形成法检测细胞的自我更新和增殖潜能。结果K562／ADM细胞对阿霉素、柔红霉素和鬼臼乙叉苷高度耐受。K562／ADM细胞中CD34^＋、CD123^＋和CD34^＋CD38^-细胞含量均显著高于K562细胞，LSC细胞相对含量是K562细胞的4．12倍；共表达P-gP和BCRP的K562／ADM细胞比K562细胞高11．25倍，其中CD34^＋CD38^-CD123^＋BCRP^＋和CD34^＋CD38^-P—gP^＋BCRP^＋细胞数量分别为K562细胞的3．66倍和11．37倍。K562／ADM细胞集落形成率是K562细胞的4．17倍，与LSC含量相当。结论白血病K562／ADM耐药细胞中存在的高表达耐药蛋白的耐药性LSC是其多药物耐受性的根源。

Objective To investigate the drug resistance, proportion of leukemia stem cells （LSC） and expression of P-glycoprotein （P-gp） and breast cancer resistance protein （BCRP） in drug-sensitive and multidrug-resistant leukemia cell population. Methods The multidrug-resistant leukemia K562/ADM cell and its parental K562 cell were used as the model cells. The drug sensitivity was tested with a MTT assay. Flow cytometry was employed to detect the immunophenotype of stem cells and the expression of P-gp and BCRP. The self-renewal and proliferating potential were examined with methylcellulose colony-forming unit assay. Results K562/ADM ceils were highly resistant to adriamyein, daunorubincin and etoposide. The amount of CD34^＋ , CD123^＋ and CD34^＋ CD38^- cells in K562/ADM cells was much higher than that in K562 cells, and the proportion of CD34^＋ CD38^-CD123^＋ cells（LSC）in K562/ADM cells was （5.23±0. 21 ）% versus （ 1.27±0. 17）% in K562 cells, which was 4. 12-fold higher than that in K562 cells. Both P-gp and BCRP were overexpressed in K562/ADM cells relative to K562 cells, and the K562/ADM cells coexpressing P-gp and BCRP were 11.25-fold higher over K562 ceils. The proportion of CD34^＋ CD38^- CD123^＋ BCRP^＋ and CD34^＋ CD38^- P-gp^＋ BCRP^＋ cells in K562/ADM cells were （4. 13±0. 40） % and （5.80±1.19）% respectively, which were 3.66- and 11.37-fold higher than the same cells in K562 cells [（1.13±0. 15）% and（0. 51±0. 01）%]. Furthermore, drug-resistant K562/ADM cells displayed 4. 17- time greater colony-forming ability over the parent K562 cells, corresponding to the proportion of LSCs in K562/ADM cells. Conclusions The ABC transporters-overexpressing LSC population exists in drug- resistant leukemic K562/ADM cells relative to drug-sensitive K562 cells, and the drug-resistant LSCs may be the source of chemotherapeutic resistance of leukemia.