Discipline of Medical Biochemistry, School of Laboratory Medicine and Medical Sciences, College of Health Sciences, University of Kwa-Zulu Natal, Durban 4041, South Africa.
Discipline of Medical Biochemistry, School of Laboratory Medicine and Medical Sciences, College of Health Sciences, University of Kwa-Zulu Natal, Durban 4041, South Africa.
Toxicol In Vitro. 2019 Jun;57:211-216. doi: 10.1016/j.tiv.2019.03.016. Epub 2019 Mar 12.
Cellular adaptation to hypoxia is controlled by hypoxia-inducible factor 1α (HIF1α), a transcription factor activated in response to oxygen tension, reactive oxygen species (ROS) and inflammation. Overexpression of HIF1α and HSP90 has been associated with cancer induction. Ochratoxin A (OTA), a mycotoxin contaminant of food and beverages, has been linked to renal tumours and progressive nephropathies, inflammation and pro-oxidation. The aim of this study was to examine the effect of OTA on hypoxic and transformative regulators in human embryonic kidney (HEK293) cells. We evaluated the protein expression of HIF1α, HSP90 and PDK1 (western blotting), mRNA expression of HIF1α, VEGF, EPO and TGFβ (qPCR), and ATP levels (luminometry) in HEK293 cells exposed to a range of OTA concentrations (0.125 μM-0.5 μM) over two time periods (24 h and 48 h). After 24 h, OTA increased HIF1α protein (p < 0.005) and EPO gene expression (p < 0.05), while VEGF and TGFβ was significantly increased at 48 h. We also observed a correlation between PDK1 expression and ATP levels. In conclusion, OTA disrupts hypoxia regulation, modulates metabolic activity, and alters growth signalling (VEGF, TGFβ), which may lead to tumourigenesis.
细胞对缺氧的适应受缺氧诱导因子 1α（HIF1α）调控，HIF1α 是一种转录因子，在氧张力、活性氧（ROS）和炎症反应的刺激下被激活。HIF1α 和 HSP90 的过度表达与癌症的发生有关。赭曲霉毒素 A（OTA）是一种食物和饮料中的真菌毒素污染物，与肾肿瘤和进行性肾病变、炎症和促氧化有关。本研究旨在研究 OTA 对人胚肾（HEK293）细胞缺氧和转化调节因子的影响。我们评估了 HIF1α、HSP90 和 PDK1 的蛋白表达（western blot）、HIF1α、VEGF、EPO 和 TGFβ 的 mRNA 表达（qPCR）以及暴露于一系列 OTA 浓度（0.125μM-0.5μM）的 HEK293 细胞中的 ATP 水平（发光法）在两个时间段（24 小时和 48 小时）内的变化。24 小时后，OTA 增加了 HIF1α 蛋白（p<0.005）和 EPO 基因表达（p<0.05），而 VEGF 和 TGFβ 在 48 小时时显著增加。我们还观察到 PDK1 表达与 ATP 水平之间存在相关性。总之，OTA 破坏了缺氧调节，调节了代谢活性，并改变了生长信号（VEGF、TGFβ），这可能导致肿瘤发生。
