Xu Kaiyue, Zhang Chunjing, Li Youbo, Xi Xin, Zheng Lishuang, Meng Ming, Liu Tongtong, Zhao Yunfeng, Li Wenjuan
College of Medicine, Hebei University, Baoding 071000, China.
Department of Biochemistry and Molecular Biology, Qiqihar Medical University, Qiqihar 161006, China.
Transl Cancer Res. 2019 Oct;8(6):2449-2460. doi: 10.21037/tcr.2019.09.57.
The metabolic enzyme isocitrate dehydrogenase 1 (IDH1) belonging to β-decarboxylase dehydrogenase family has been identified as a tumor suppressor. Withaferin A (WA), a bioactive compound derived from , has the anti-tumor activity. Based on the data set that WA inhibited 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced IDH1 inactivation and mitochondrial dysfunction, we focused on how WA suppressed the skin carcinogenesis mediated by IDH1.
The mRNA levels of IDH1 were measured after treated with TPA and/or WA. The expression of IDH1, lactate dehydrogenase (LDH) involved in glycolysis, hypoxia inducible factor-1α (HIF-1α) and its target gene glucose transporter-1 (Glut1) were detected. The activities of proteasome and the mitochondrial complex I related to mitochondrial functions were determined. The enzymatic activities of LDH, proline hydroxylase (PHD) and vascular endothelial growth factor (VEGF) were analyzed.
The qPCR data have shown the mRNA levels of IDH1 were no difference with TPA and/or WA treatment. Next, data demonstrated that WA could stabilize IDH1 by inhibiting the ubiquitin-proteasome pathway (UPP). Followed by illuminating the mechanism of IDH1 inhibiting tumorigenesis, the results mirrored that upregulated IDH1 suppressed LDH activity whereas increased mitochondrial complex I activity. Furthermore, via its product α-KG, upregulated IDH1 activated PHD, and inhibited HIF-1α and its downstream signaling pathway.
Our results indicate that WA inhibits tumor promotion partially via stabilizing IDH1, leading to inactivating the HIF-1α signaling.
代谢酶异柠檬酸脱氢酶1（IDH1）属于β-脱羧酶脱氢酶家族，已被确定为一种肿瘤抑制因子。非洲狼毒内酯A（WA）是一种从[来源未提及]中提取的生物活性化合物，具有抗肿瘤活性。基于WA抑制12-O-十四烷酰佛波醇-13-乙酸酯（TPA）诱导的IDH1失活和线粒体功能障碍的数据集，我们重点研究了WA如何抑制由IDH1介导的皮肤癌发生。
用TPA和/或WA处理后测量IDH1的mRNA水平。检测IDH1、参与糖酵解的乳酸脱氢酶（LDH）、缺氧诱导因子-1α（HIF-1α）及其靶基因葡萄糖转运蛋白-1（Glut1）的表达。测定与线粒体功能相关的蛋白酶体和线粒体复合体I的活性。分析LDH、脯氨酸羟化酶（PHD）和血管内皮生长因子（VEGF）的酶活性。
qPCR数据显示，TPA和/或WA处理后IDH1的mRNA水平无差异。接下来，数据表明WA可以通过抑制泛素-蛋白酶体途径（UPP）来稳定IDH1。在阐明IDH1抑制肿瘤发生的机制后，结果表明上调的IDH1抑制LDH活性，而增加线粒体复合体I的活性。此外，上调的IDH1通过其产物α-KG激活PHD，并抑制HIF-1α及其下游信号通路。
我们的结果表明，WA部分通过稳定IDH1来抑制肿瘤促进，从而使HIF-1α信号失活。
