O—GlcNAc糖基化对Nalm-6细胞生物学行为及依托泊苷诱导凋亡的影响

O-GIcNAc glycosylation influences the biological behaviors and etoposideinduced apoptosis of Nalm-6 cells

目的研究O连接的N-乙酰葡萄糖胺（O-GlcNAc）糖基化及乙酰氨基葡萄糖转移酶（OGT）对Nalm-6细胞生物学行为及对依托泊苷（Vp16）诱导凋亡的影响。方法利用OGT抑制剂Alloxan构建低O—GlcNAc修饰的Nalm-6细胞模型，CCK-8法检测Alloxan对细胞增殖的影响，流式细胞术检测Alloxan对细胞凋亡及细胞周期的影响；以不同浓度的Vp16处理Nalm-6细胞12h，Westernblot检测O—GlcNAc糖基化修饰程度及OGT表达量的变化；以Alloxan处理Nalm-6细胞24h后再加入vp16（5gg／m1）处理12h，应用流式细胞术检测不同组别细胞凋亡，Western blot检测凋亡相关蛋白Bax和Bcl-2的表达情况。结果随着Vpl6浓度的增加，Nalm-6细胞O—GlcNAc修饰及OGT表达均逐渐上调（P〈0．05）；Alloxan可抑制Nalm-6细胞增殖，诱发Nalm-6细胞凋亡[（15．190±2．539）％对（21．910±4．105）％，P=0．007]，阻滞细胞周期[G。期：（43．534±4．453）％对（57．322±6．091）％，P=-0．003；S期：（50．747±5．937）％对（37．201±4．661）％，P=0．001]；Alloxan可抑制Vp16诱导的Nahn-6细胞凋亡[（75．195±13．845）％对（52．741±10．815）％，P=0．011]，并伴随Bax表达下调（5．496±1．998对2．950±0．703，P=0．015）、Bcl、2表达上调（0．454±0．125对0．803±0．223，P=0．013）。结论通过抑制OGT而改变Nalm-6细胞O—GlcNAc修饰程度可影响其增殖、凋亡、改变细胞周期并抑制vp16诱导的细胞凋亡。

Objective To explore the effects ofO-GlcNAc glycosylation and its key enzyme OGT on the biological behaviors and etoposide （Vpl6） - induced apoptosis of Nalm-6 cells. Methods Low O-GlcNAc modified Nalm-6 cells model was established with Alloxan, an inhibitor of OGT. The influence of Alloxan on Nalm- 6 cells proliferation was checked by CCK- 8 assay, apoptosis and cell cycle by flow cytometry. Nalm- 6 cells were treated with different concentrations of Vpl6 for 12 h, and then the O-GlcNAc level and the expressions of OGT were examined by Western blot. After treating Nalm-6 with Alloxan for 24 h and then 5 μg/ml of Vp16 for 12 h, the apoptosis of different groups were measured with flow cytometry, and the expression of apoptosis-associated proteins Bax and Bcl-2 were examined by Western blot. Results With the concentration of Vpl6 increasing, the O-GlcNAc modified levels of total protein and the expression of OGT were up regulated （P〈0.05, n=6）; Alloxan could slow down the proliferation capacity, induce apoptosis [ （ 15.190±2.539 ） % vs （21.910＋4.105 ） %, P=0.007 ], arrest cell cycle [G1 phase： （43.534±4.453）% vs （57.322±6.091）%, P=-0.003; S phase： （50.747±5.937）% vs （37.201± 4.661 ）%, P=0.001 ]. Alloxan could inhibit the apoptosis caused by Vp16 [ （75.195±13.845）% vs （52.741± 10.815）%, P=-0.011] along with Bax decreasing （5.496± 1.998 vs 2.950±0.703, P=-0.015） and Bcl-2 increasing （0.454＋0.125 vs 0.803±0.223, P=0.013）. Conclusion Changes of O-GlcNAc modified level of Nalm- 6 cells along with the inhibition of OGT could influence the biological behaviors and inhibit apoptosis induced by Vp 16.