人白血病细胞株对L-门冬酰胺酶敏感性与门冬酰胺合成酶表达水平的相关性

Relationship between Asparagine Synthetase Expression Level and Cell Sensitivity to L-asparaginase in Human Leukemic Cell Lines

本研究探讨人白血病细胞株门冬酰胺合成酶(asparagine synthetase,AsnS)的表达水平及与白血病细胞株对L-Asparaginase(L-Asp)敏感性的关系。用实时定量PCR技术(real-time quantitative PCR,RQ-PCR)检测Jurkat,HL-60,U937,NB4,THP-1,Namalwa,Karpas299和K562等8种细胞株基础的和经L-Asp处理后的AsnS表达水平,用CCK-8实验检测细胞对L-Asp处理的敏感性。结果表明,8种细胞株之间AsnS的基础表达水平存在很大程度的变异,经L-Asp处理后细胞株的AsnS表达显著上调(p<0.05),AsnS低水平表达细胞对L-Asp相对敏感,而AsnS高表达细胞对L-Asp相对耐药。在8种细胞株中,U937对L-Asp高度敏感,其AsnS表达水平最低,而K562细胞株对L-Asp天然耐药,AsnS表达水平最高。结论:AsnS在天门冬氨酸耗竭后的细胞生物学行为中起着重要的作用,AsnS的表达水平反映了细胞对L-Asp的敏感性,L-Asp在AsnS低表达白血病的治疗中有潜在的应用价值。

This study was purposed to explore the relationship between asparagine synthetase （AsnS） mRNA expression level and the sensitivity of leukemic cell lines to L-asparaginase. The AsnS mRNA expression level in 8 cell lines （Jurkat, HL-60, U937, NB4, THP-1, Namalwa, Karpas299 and K562） was determined by real-time quantitative PCR （RQ-PCR） based on fluorescence dye Eva Green before and after treatment with L-Asp, and the cell proliferation rates were analyzed by CCK-8 assay. The results showed that there was a significant disparity of AsnS expression level in 8 cell lines, and there were significant increases of AsnS expression level in cells co-cultured with L-Asp （p 〈 0.05）. Of all these eight cell lines, cells sensitive to L-asparaginase had lower AsnS expression level and cells resistant to L-asparaginase had higher AsnS expression. U937 which was the most sensitive to L-asparaginase had the lowest AsnS expression level, while K562 was natural resistant to L-asparaginase and possessed of the highest AsnS level. It is concluded that the AsnS plays a critical role in regulating cellular biological behavior after depletion of asparagine, the AsnS mRNA expression level in cells reflects the sensitivity of cells to L-Asp. The results may imply the possibility for the use of L-asparaginase in leukemia with lower AsnS expression level.