糖酵解在预测和逆转急性淋巴细胞白血病糖皮质激素耐药中的核心作用

Treatment failure in pediatric acute lymphoblastic leukemia (ALL) is related to cellular resistance to glucocorticoids (GCs). Early prediction and reversing GC resistance is indeed an urgent and pressing task to be done. Our recent work indicated that almost all the patients with GC resistance were accompanied by a high rate of glycolysis, and inhibition of glycolysis could reverse the GC resistance effectively in lymphoid tumors. Further study revealed that down-regulation of glycolysis rate might be the main mechanism responsible for the reversion of GC resistance by mTOR inhibitor. We hypothesize that high rate of glycolysis might be the core mechanmism of GC resistance in the impaired signaling pathways. Therefore, we plan to study on ALL cell lines, samples of patients, and nude mice models of ALL, and try to identify the key role of glycolysis in GC resistance by inhibiting and activating glycolysis. In the meantime, we propose to use isobaric tags for relative and absolute quantitation (iTRAQ) technique to compare protein expression levels among multiple samples, including GC resistant and sensitive cell lines and the cells sensitized by inhibition of glycolysis and cells treated by GC, which will provide a comprehensive insight into mechanisms of GC resistance and find out biomarkers and new therapeutic targets to overcome GC resistance. This work will help us to develop a highly effective, but less toxic combination chemotherapy protocol for ALL patients, especially for GC resistant patients.

糖皮质激素（GC）耐药是导致急性淋巴细胞白血病（ALL）治疗失败的重要原因，在治疗早期预测并逆转耐药是目前亟待解决的难题。我们前期研究发现，ALL GC耐药患者常伴糖酵解过度活化；在淋巴肿瘤细胞，抑制糖酵解可有效逆转GC耐药；mTOR抑制剂可能是通过抑制糖酵解逆转GC耐药。提示，过度活化的糖酵解可能在复杂的GC耐药信号路径中起着核心作用。本研究拟从细胞株、患者原代细胞、ALL裸鼠模型，三个层面深入，通过抑制和活跃糖酵解明确其在GC耐药中的作用；并应用同位素标记相对和绝对定量（iTRAQ）质谱技术比较GC敏感、耐药、抑制糖酵解恢复敏感后细胞蛋白质组表达谱差异，以及GC作用后蛋白质组表达谱差异，对多信号通路整合研究，力图诠释糖酵解在GC耐药中的核心作用和机制，并找到早期预测GC耐药的生物标志物，甚至提供新的治疗靶点，高效逆转耐药，为ALL患者,尤其是GC耐药患者提供高效低毒的化疗方案。

糖皮质激素（GC）耐药是导致急性淋巴细胞白血病（ALL）治疗失败的重要原因，在治疗早期预测并逆转耐药是目前临床亟待解决的难题。本研究从细胞株、患者原代细胞和ALL裸鼠模型，三个层面深入，通过抑制和活跃糖酵解明确其在GC耐药中的作用；并应用同位素标记相对和绝对定量（iTRAQ）质谱技术比较GC敏感、耐药、抑制糖酵解恢复敏感后细胞蛋白质组表达谱差异，以及GC作用后蛋白质组表达谱差异，对多信号通路整合研究。结果发现，靶向mTOR/p70S6K/糖酵解通路可有效逆转淋巴肿瘤细胞GC耐药；低氧条件培养进一步活化糖酵解并诱导GC耐药；糖酵解抑制剂2-DG在低浓度时是通过抑制N-连接糖基化，进而诱导内质网（ER）应激从而逆转ALL和淋巴瘤细胞GC耐药，提示ER应激在ALL GC耐药中起重要作用；糖酵解相关的Glut-1、HKⅡ、PKM2、LDHA等蛋白表达水平与GC耐药无明显相关；凋亡相关蛋白Bim与c-MYC可能作为早期预测GC耐药的指标，需扩大样本量进一步研究。蛋白组学的研究提示GC敏感和GC耐药细胞在糖和脂肪代谢存在显著差异，提示我们深入代谢组学的研究，寻找GC耐药的生物标志物及治疗靶点。