Abstract：
BACKGROUND: Targeting glycolysis in cancer is an attractive approach for therapeutic intervention. 2-Deoxyglucose (2DG) is a synthetic glucose analog that inhibits glycolysis. However, its efficacy is limited by the systemic toxicity at high doses. Understanding the mechanism of 2DG resistance is important for further use of this drug in cancer treatment.
METHODS: The expression of thioredoxin-1 (Trx-1) in colorectal cancer (CRC) cells treated with 2DG was detected by Western blotting. The effect of Trx-1 on the cytotoxicity of 2DG in CRC cells was examined in vitro and in vivo. The molecular mechanism involved in Trx-1-mediated activation of the SLC1A5 gene promoter activity was elucidated using in vitro models.
RESULTS: Inhibition glycolysis with 2DG increased the expression of Trx-1 in CRC cells. Overexpression of Trx-1 decreased the cytotoxicity of 2DG, whereas knockdown of Trx-1 by shRNA significantly increased the cytotoxicity of 2DG in CRC cells. The Trx-1 inhibitor PX-12 increased the cytotoxicity of 2DG on CRC cells both in vitro and in vivo. In addition, Trx-1 promoted SLC1A5 expression by increasing the promoter activity of the SLC1A5 gene by binding to SP1. We also found that the SLC1A5 expression was upregulated in CRC tissues, and inhibition of SLC1A5 significantly enhanced the inhibitory effect of 2DG on the growth of CRC cells in vitro and in vivo. Overexpression of SLC1A5 reduced the cytotoxicity of 2DG in combination with PX-12 treatment in CRC cells.
CONCLUSIONS: Our results demonstrate a novel adaptive mechanism of glycolytic inhibition in which Trx-1 increases GSH levels by regulating SLC1A5 to rescue cytotoxicity induced by 2DG in CRC cells. Inhibition of glycolysis in combination with inhibition of Trx-1 or SLC1A5 may be a promising strategy for the treatment of CRC.
METHODS: The expression of thioredoxin-1 (Trx-1) in colorectal cancer (CRC) cells treated with 2DG was detected by Western blotting. The effect of Trx-1 on the cytotoxicity of 2DG in CRC cells was examined in vitro and in vivo. The molecular mechanism involved in Trx-1-mediated activation of the SLC1A5 gene promoter activity was elucidated using in vitro models.
RESULTS: Inhibition glycolysis with 2DG increased the expression of Trx-1 in CRC cells. Overexpression of Trx-1 decreased the cytotoxicity of 2DG, whereas knockdown of Trx-1 by shRNA significantly increased the cytotoxicity of 2DG in CRC cells. The Trx-1 inhibitor PX-12 increased the cytotoxicity of 2DG on CRC cells both in vitro and in vivo. In addition, Trx-1 promoted SLC1A5 expression by increasing the promoter activity of the SLC1A5 gene by binding to SP1. We also found that the SLC1A5 expression was upregulated in CRC tissues, and inhibition of SLC1A5 significantly enhanced the inhibitory effect of 2DG on the growth of CRC cells in vitro and in vivo. Overexpression of SLC1A5 reduced the cytotoxicity of 2DG in combination with PX-12 treatment in CRC cells.
CONCLUSIONS: Our results demonstrate a novel adaptive mechanism of glycolytic inhibition in which Trx-1 increases GSH levels by regulating SLC1A5 to rescue cytotoxicity induced by 2DG in CRC cells. Inhibition of glycolysis in combination with inhibition of Trx-1 or SLC1A5 may be a promising strategy for the treatment of CRC.
摘要：
背景：在癌症中靶向糖酵解是一种有吸引力的治疗干预方法。2-脱氧葡萄糖(2DG)是抑制糖酵解的合成葡萄糖类似物。然而,其疗效受到高剂量时全身毒性的限制。了解2DG耐药的机制对于该药物在癌症治疗中的进一步使用非常重要。
方法：采用Western印迹法检测2DG处理的结直肠癌（CRC）细胞中硫氧还蛋白-1（Trx-1）的表达。在体外和体内检测了Trx-1对CRC细胞中2DG细胞毒性的影响。使用体外模型阐明了Trx-1介导的SLC1A5基因启动子活性激活的分子机制。
结果：用2DG抑制糖酵解增加了CRC细胞中Trx-1的表达。过表达Trx-1降低了2DG的细胞毒性,而shRNA敲除Trx-1显著增加了CRC细胞中2DG的细胞毒性。Trx-1抑制剂PX-12在体外和体内都增加了2DG对CRC细胞的细胞毒性。此外,Trx-1通过与SP1结合增加SLC1A5基因的启动子活性来促进SLC1A5的表达。我们还发现SLC1A5在CRC组织中表达上调,和抑制SLC1A5显著增强了2DG对CRC细胞的体外和体内生长的抑制作用。SLC1A5的过表达降低了CRC细胞中与PX-12处理组合的2DG的细胞毒性。
结论：我们的结果证明了一种新的糖酵解抑制的适应性机制，其中Trx-1通过调节SLC1A5来增加GSH水平，以挽救2DG在CRC细胞中诱导的细胞毒性。抑制糖酵解与抑制Trx-1或SLC1A5组合可能是治疗CRC的有希望的策略。
方法：采用Western印迹法检测2DG处理的结直肠癌（CRC）细胞中硫氧还蛋白-1（Trx-1）的表达。在体外和体内检测了Trx-1对CRC细胞中2DG细胞毒性的影响。使用体外模型阐明了Trx-1介导的SLC1A5基因启动子活性激活的分子机制。
结果：用2DG抑制糖酵解增加了CRC细胞中Trx-1的表达。过表达Trx-1降低了2DG的细胞毒性,而shRNA敲除Trx-1显著增加了CRC细胞中2DG的细胞毒性。Trx-1抑制剂PX-12在体外和体内都增加了2DG对CRC细胞的细胞毒性。此外,Trx-1通过与SP1结合增加SLC1A5基因的启动子活性来促进SLC1A5的表达。我们还发现SLC1A5在CRC组织中表达上调,和抑制SLC1A5显著增强了2DG对CRC细胞的体外和体内生长的抑制作用。SLC1A5的过表达降低了CRC细胞中与PX-12处理组合的2DG的细胞毒性。
结论：我们的结果证明了一种新的糖酵解抑制的适应性机制，其中Trx-1通过调节SLC1A5来增加GSH水平，以挽救2DG在CRC细胞中诱导的细胞毒性。抑制糖酵解与抑制Trx-1或SLC1A5组合可能是治疗CRC的有希望的策略。
