阿霉素增强TRAIL诱导的人骨髓瘤细胞系KM3细胞凋亡的分子机制研究

Study of molecular mechanism of doxorubicin enhancement of TRAIL inducing apoptosis of myeloma cell line KM3

目的探讨阿霉素增强肿瘤坏死因子相关凋亡诱导配体（TRAIL）诱导人骨髓瘤细胞系KM3细胞凋亡的分子机制。方法采用TUNEL法和流式细胞术比较单独TRAIL及联合应用阿霉素对KM3细胞凋亡率的影响。Westem blot法检测阿霉素诱导前后KM3细胞核内转录因子NF-κB亚单位蛋白P65以及死亡受体DR5表达的变化。结果流式细胞术分析显示，10、20、50、100ng／ml的TRAIL联合应用1μg／ml阿霉素诱导KM3细胞后，细胞凋亡率分别为20．88％、40．03％、57．87％和60．82％，显著高于单独应用阿霉素或TRAIL诱导的细胞凋亡率；与TUNEL法检测结果一致。KM3细胞经不同浓度阿霉素（0．5、1．0、2．0、4．0μg／m1）联合20ng／ml TRAIL处理后，DR5受体的表达量随应用阿霉素浓度的增加而上升，而细胞核内P65蛋白表达量则随阿霉素浓度的增加而下降。结论骨髓瘤细胞膜DR5表达量提高和NF-κB的核转移是阿霉素协同TRAIL诱导凋亡反应的重要分子机制。

Objective To investigate the molecular mechanism of doxorubicin enhancement of tumor necrosis factor-related apoptosis-inducing ligand （TRAIL） inducing apoptotic effect on multiple myeloma cell line KM3. Methods Apoptosis was studied independently through flow cytometry analysis and TUNEL staining. The expression of death receptor 5 （ DR5 ） and nuclear factor P65 in nucleas was examined by Western blot. Results The apoptosis ratio of KM3 cells was 20.88%, 40.03%, 57.87%, 60.82% respectively when treated with different concentration of TRAIL（ 10,20,50,100 ng/ml） combining with doxorubicin. It is markedly higher than the group treated with TRAIL or doxorubicin alone. DR5 expression increased while P65 decreased as the doses of doxorubin increased when KM3 cells treated with doxorubin （0.5,1.0,2.0 and 4.0 μg/ml） plus 20 ng/ml TRAIL. Conclusion Increasing the expression of DR.5 and nuclear transfering of P65 are the important molecular mechanism by which doxorubicin enhances TRAIL-inducing apoptosis of KM3 ceils.