Abstract 426: Suppression of cell invasion and migration by inhibitors to ROS level in human lung cancer cells

Abstract

Abstract Suppression of cell invasion and migration by inhibitors to ROS level in human lung cancer cells Chih-hsien Huang, Chun-Yu Cho, Shih-Ying Chun, Chih-Chen Hong, Shuang-En Chuang National Institute of Cancer Research, National Health Research Institutes, Miaoli county, Taiwan Abstract: Accumulating evidence has implicated oxidative stress in the regulation of cancer cell behavior, including proliferation, invasiveness and metastasis. Oxidative stress can generate large amount of reactive oxygen species (ROS) in response to various the regulation from endogenous or exogenous stimulation. It is widely accepted that increased ROS levels are considered to be closely linked to the increased metastasis and the removal of ROS is a rational strategy to inhibit metastasis (Nishikawa Cancer letters 2008; 266:53-59). To explore this hypothesis, the human lung adenocarcinoma, CL1 series of cell lines (i.e., CL1-0, CL1-3, and CL1-5, increasing invasiveness), was established by selection of cancer cell populations of gradually increasing invasiveness using the Transwell invasion chamber assay. We have observed that the CL1 sublines have increased ROS levels in parallel with the trend of invasiveness, using 2’-7’-dichlorodihydrofluorescein diacetate (DCF-DA) as a probe to detect and quantify ROS. Further, we evaluated the expression of various NADPH oxidase (NOX) isoforms with RT-PCR analysis. There were no significant differences in the expression of NOX2, NOX4, NOX5, and p22phox, except that NOX1 was detected in none of the CL1 sublines. Only the mRNA expression of ENOX2 (the external cell surface form of NOX), a tumor-associated NADH oxidase, has a trend parallel with increased ROS levels. Similarly, Western blotting showed a linear correlation between ROS levels and the respective steady-state levels of cellular ENOX2. In parallel with the amount of ENOX2 protein, the steady-state levels of superoxide were also increased in CL1 sublines using a modified colorimetric nitro-blue tetrazolium (NBT) assay. Our observations from wound healing assay have clearly migration ability of shown that both N-acetylcysteine (NAC) and diphenyliodonium (DPI) can inhibit migration ability of CL1-5 cells. Due to NAC and DPI inhibit ROS generation, the role of ROS in metastasis was further evaluated by matrigel traswell assay using CL1-5 cells that have high invasive potential. Similarly, NAC efficiently inhibits CL1-5 cells invasion in a dosage dependent manner. From the result of MMP zymophgraphy, decreased MMPs, such as MMP-2 and MMP-9, by NAC treatment suggests that endogenous ROS may play an important role in cell migration and invasion. Since NAC and DPI reduce endogenous ROS level by directly neutralizing ROS and inhibiting NADPH oxidase respectively, these data indicate that ROS participates in the regulation of cancer cell migration and invasion. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 426.