Soonchunhyung Environmental Health Center for Asbestos-related Disease, College of Medicine, Soonchunhyang University, Cheonan Hospital, Cheonan 330-090, Republic of Korea.
Food Chem Toxicol. 2012 Feb;50(2):116-23. doi: 10.1016/j.fct.2011.10.035. Epub 2011 Oct 14.
The nuclear factor erythroid-derived 2 related factor 2 (Nrf2)/heme oxygenase (HO)-1 induction plays cytoprotective roles against oxidative injury, apoptosis, and anticancer therapy; however, little is known about its regulation in human mesothelioma MSTO-211H cells. In this study, we investigated Nrf2/HO-1 induction in response to sulforaphane and determined the signaling pathways involved in this process. Sulforaphane treatment decreased cell viability and triggered a rapid and transient increase in the intracellular ROS levels. Pretreatment with N-acetylcysteine (NAC) prevented sulforaphane-induced cytotoxicity. Erk1/2 was activated within 1h of sulforaphane addition, whereas Akt phosphorylation was suppressed until the first 8h, and was then maintained at an elevated level until 72h, displaying a biphasic regulatory feature. Nrf2 protein levels in both nuclear and whole cell lysates were increased after sulforaphane treatment and were decreased by pretreatment with NAC, actinomycin D and cycloheximide. Activation of the Nrf2/HO-1 system after sulforaphane treatment was suppressed by pretreatment with NAC or Ly294002, a PI3K inhibitor. Knockdown of Nrf2 with siRNA decreased cell viability and attenuated sulforaphane-induced HO-1 up-regulation. Overall, our results indicate that ROS generation and/or activation of PI3K/Akt signaling regulate cell survival and Nrf2-driven HO-1 expression in sulforaphane-treated MSTO-211H cells.
核因子红细胞 2 相关因子 2（Nrf2）/血红素加氧酶（HO）-1 的诱导在对抗氧化损伤、细胞凋亡和抗癌治疗中发挥细胞保护作用；然而，人们对其在人胸膜间皮瘤 MSTO-211H 细胞中的调节知之甚少。在这项研究中，我们研究了对萝卜硫素的 Nrf2/HO-1 诱导作用，并确定了参与这一过程的信号通路。萝卜硫素处理降低了细胞活力，并引发了细胞内 ROS 水平的快速和短暂增加。用 N-乙酰半胱氨酸（NAC）预处理可预防萝卜硫素诱导的细胞毒性。萝卜硫素添加后 1 小时内激活了 Erk1/2，而 Akt 磷酸化在最初 8 小时内被抑制，然后维持在升高的水平直到 72 小时，呈现出双相调节特征。萝卜硫素处理后，核和全细胞裂解物中的 Nrf2 蛋白水平增加，并用 NAC、放线菌素 D 和环己酰亚胺预处理后减少。用 NAC 或 PI3K 抑制剂 Ly294002 预处理可抑制萝卜硫素处理后 Nrf2/HO-1 系统的激活。用 siRNA 敲低 Nrf2 会降低细胞活力并减弱萝卜硫素诱导的 HO-1 上调。总的来说，我们的结果表明，ROS 的产生和/或 PI3K/Akt 信号的激活调节了萝卜硫素处理的 MSTO-211H 细胞中的细胞存活和 Nrf2 驱动的 HO-1 表达。
