重组变构人TRAIL联合柔红霉素对白血病细胞诱导凋亡作用及其机制的研究

为了研究重组变构人肿瘤坏死因子相关凋亡诱导配体（recombinanat mutant human TRAIL, rmhTRAIL）单用及与柔红霉素（DNR）联合应用对白血病细胞株U937、K562的诱导凋亡作用及其机制，以正常人胚肺成纤维细胞株MRC-5作对照，采用MTT法检测体外培养的U937、K562白血病细胞株在rmhTRAIL单用和联合DNR作用下增殖的抑制效应；用半定量逆转录多聚酶链反应（RT-PCR）法检测DNR处理前后白血病细胞TRAIL死亡受体和诱杀受体的mRNA表达水平。结果表明：rmhTRAIL对白血病细胞株U937、K562有较明显的抑制增殖作用，DNR与TRAIL联合对抑制肿瘤细胞具有协同性，与各药单独使用比较均有显著差异（P〈0．05）；经DNR作用后，U937、K562细胞的死亡受体DR4、DR5水平上调，而两种诱杀受体DcR1、DcR2表达未受影响。结论：在体外rmhTRAIL单用或与DNR联用均能明显抑制白血病细胞增殖，rmhTRAIL与DNR对白血病细胞的杀伤有协同作用。其诱导机制可能与U937、K562细胞死亡受体DR4、DR5表达水平上调有关。

Combined Effect of Recombinant Mutant Human TRAIL and Daunorubicin in Inducing Apoptosis of Leukemia Cell and Its Mechanism

The aim of study was to investigate the combined effect of recombinomt muctant human TRAIL (rmhTRAIL) with daunorubicin (DNR) or alone on K562 and U937 leukemia cell lines and its mechanism. The fibroblasts (MRC-5) of normal-human embryonic lung were used as control cells. After being treated with rmhTRAIL and DNR or only with rmTRAIL, the cytotoxic effect and the apoptosis rate in K562, U937 cells were measured by MTT assay. The expression levels of TRAIL death receptor and TRAIL decoy receptor mRNA in these three cell lines were assayed by semiquantitive RT-PCR befor and after treatment with DNR. The results indicated that K562 and U937 were sensitive to rmhTRIAL. DNR had synergistic inhibitory effect with rmhTRAIL on the growth of K562 and U937 cell lines (P<0.05). The expression level of DR4 and DR5 mRNA was significantly higher in K562 and U937 with combined treatment of rmhTRAIL and DNR than that in those alone, while the expressions of DcR1 and DcR2 mRNA were not influenced. It is concluded that in vitro, rmhTRAIL alone or in combination with DNR can obviously inhibite the growth of leukemia cell lines and induce cell apoptosis, DNR and rmhTRAIL have a synergistic inhibitory effect on growth of K562 and U937. The mechanism may correlate with the up-regulation of DR4 and DR5 of K562 and U937.