Nicotinamide N-methyltransferase decreases 5-fluorouracil sensitivity in human esophageal squamous cell carcinoma through metabolic reprogramming and promoting the Warburg effect
Nicotinamide N-methyltransferase decreases 5-fluorouracil sensitivity in human esophageal squamous cell carcinoma through metabolic reprogramming and promoting the Warburg effect
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DOI：
10.1002/mc.23209
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发表时间：
2020-05-04
影响因子：
4.6
通讯作者：
Guan, Fangxia
中科院分区：
文献类型：
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作者：
Cui, Yanyan;Yang, Dawei;Guan, Fangxia
食管鳞癌(ESCC)是一种常见的恶性肿瘤，预后不良。不同的人对同一种药物的反应也不同。越来越多的证据证实，代谢重编程参与了肿瘤细胞的药物敏感性。然而，5-氟尿嘧啶(5-FU)在ESCC细胞中敏感性的潜在分子机制仍有待阐明。在本研究中，我们发现TE1细胞对5-FU的敏感性低于EC1和Eca109细胞。气相色谱-质谱联用分析结果表明，三种细胞的烟酸盐和烟酰胺代谢及三元酸循环存在明显差异。烟酰胺N-甲基转移酶(NNMT)是烟酸和烟酰胺代谢的关键酶，在TE1细胞中的表达显著高于EC1和Eca109细胞。因此，我们在体内外分析了NNMT对5-FU敏感性的影响。NNMT下调显著增加了TE1细胞对5-FU的敏感性。同时，在NNMT基因敲除的TE1细胞中，葡萄糖消耗和乳酸产生减少，糖酵解相关酶己糖激酶2、乳酸脱氢酶A和磷酸甘油变位酶1的表达下调。此外，NNMT在EC1和Eca109细胞中的过表达也产生了相反的作用。此外，当2-脱氧葡萄糖抑制糖酵解时，NNMT对5-FU敏感性的作用减弱。体内实验表明，NNMT基因敲除显著增加了移植瘤对5-FU的敏感性，并抑制了Warburg效应。总之，这些结果表明NNMT通过促进Warburg效应降低了人ESCC细胞对5-FU的敏感性，提示NNMT可能有助于预测临床化疗对ESCC的疗效。
Esophageal squamous cell carcinoma (ESCC) is a common malignant tumor with poor prognosis. And different individuals respond to the same drug differently. Increasing evidence has confirmed that metabolism reprogramming was involved in the drug sensitivity of tumor cells. However, the potential molecular mechanism of 5-fluorouracil (5-FU) sensitivity remains to be elucidated in ESCC cells. In this study, we found that the 5-FU sensitivity of TE1 cells was lower than that of EC1 and Eca109 cells. Gas chromatography-mass spectrometry analysis results showed that nicotinate and nicotinamide metabolism and tricarboxylic acid cycle were significantly different in these three cell lines. Nicotinamide N-methyltransferase (NNMT), a key enzyme of nicotinate and nicotinamide metabolism, was significantly higher expressed in TE1 cells than that in EC1 and Eca109 cells. Therefore, the function of NNMT on 5-FU sensitivity was analyzed in vitro and in vivo. NNMT downregulation significantly increased 5-FU sensitivity in TE1 cells. Meanwhile, the glucose consumption and lactate production were decreased, and the expression of glycolysis-related enzymes hexokinase 2, lactate dehydrogenase A, and phosphoglycerate mutase 1 were downregulated in NNMT knockdown TE1 cells. Besides, overexpression of NNMT in EC1 and Eca109 cells caused the opposite effects. Moreover, when glycolysis was inhibited by 2-deoxyglucose, the roles of NNMT on 5-FU sensitivity was weakened. In vivo experiments showed that NNMT knockdown significantly increased the sensitivity of xenografts to 5-FU and suppressed the Warburg effect. Overall, these results demonstrated that NNMT decreases 5-FU sensitivity in human ESCC cells through promoting the Warburg effect, suggesting that NNMT may contribute to predict the treatment effects of the clinical chemotherapy in ESCC.