人质膜型唾液酸酶与人红白血病细胞多药耐药相关

Relationship between human membrane associated sialidase (Neu3) and multidrug resistance (MDR) in K562 cell line

目的探讨人质膜型唾液酸酶(Neu3)与人红白血病细胞多药耐药的关系。方法分别或联合柔红霉素(DNR)与唾液酸酶特异性抑制剂(NeuAC2en)处理K562和K562/ADM细胞,MTT法检测细胞生存率;RT-PCR检测多药耐药基因(MDR)、多药耐药相关蛋白(MRP)、06-甲基鸟嘌呤-DNA甲基转移酶(MGMT)、谷胱甘肽S转移酶(GST)、BCL-xl、BAX和BCL-2mRNA表达;Western blot法检测MDR基因蛋白产物P-糖蛋白(P-gp)蛋白表达;TBA法检测唾液酸酶活性。结果与K562细胞相比,K562/ADM细胞对DNR具有一定的抵抗性,NeuAC2en与DNR有协同作用(P<0.01);应用NeuAC2en或DNR后K562和K562/ADM细胞Neu3活性均明显下降,两种药物联合应用Neu3活性下降最明显(P<0.01);相同处理条件下,与K562细胞相比,K562/ADM细胞中Neu3、MDR1、BCL-xl和BCL-2表达增加,BAX无明显变化;应用DNR后,MDR1、Neu3、BCL-xl、BCL-2表达均下降,而DNR与NeuAC2en联合应用,以上基因表达水平下调最明显。结论Neu3可能通过影响细胞凋亡和MDR1的表达从而增强肿瘤细胞的多药耐药性。

Objective To investigate the role of human membrane associated sialidase （Neu3） in multidrug resistance （MDR） of K562 cells. Methods K562 cells and K562/ADM cells were treated with DNR alone or with combination of DNR and NeuAC2en. The cell survival rate was measured by MTT assay ; the expression of MDR related factors and apoptosis related factors were determined by Western blot and RT-PCR; Neu3 activity was detected by TBA reaction. Results The survival rate of K562/ADM cells was higher than that of K562 cells; NeuAC2en showed synergistic effect with DNR（P 〈0. 01 ） ; Neu3 activity of K562 and K562/ADM cells decreased after DNR or NeuAC2en induction and the decrease was most significant in the combination treatment group（P 〈0. 01 ）. Under the identical condition, the protein expression of P-gp and Neu3 and the mRNA expression of MDR1, Neu3, BCL-xl and BCL-2 increased comparing with K562 cells. The mRNA level of BAX in K562 and K562/ADM groups did not changed significantly. MDR1, Neu3 ,BCL-xl and BCL-2 decreased after DNR induction and down-regulated most obviously in the groups treated by DNR combined with NeuAC2en. Conclusion Neu3 may be related with muhidrug resistance of K562/ADM cell through regulating apoptosis and the expression of MDR1.