NOX4通过增强非小细胞肺癌有氧糖酵解促进其恶性进展的研究

Previous studies have shown the close correlation of NADPH oxidase (Nicotinamide adenine dinucleotide phosphate oxidase, NOX) with cancer malignant progression. However, the underlying mechanisms remain unclear. Our work showed the positive correlation of NOX4 expression with NSCLC clinical stage progression. In NSCLC cell lines, we found that overexpression of NOX4 enhances cell growth and invasion via inhibition of PTEN protein phosphatase activity partly through NOX4-derived ROS production. Enhanced aerobic glycolysis has been confirmed to promote cancer malignant progression. Our data showed that inhibition of aerobic glycolysis obviously reversed the enhancement effect of NOX4 overexpression on NSCLC cell growth and invasion. This finding suggests that NOX4 promotes NSCLC cell growth and metastasis possibly through stimulating cell aerobic glycolysis. PTEN activity deficiency has well been accepted to stimulate cancer cell aerobic glycolysis. Therefore, in view of above data, we put forward the research proposal as follows: NOX4 stimulates NSCLC cell aerobic glycolysis through inhibition of PTEN activity, thus promoting NSCLC malignant progression. We will verify such proposal thoroughly at different experimental levels. Besides, in view of our preliminary data, we propose a new possible mechanism accounting for NOX4-mediated inhibition of PTEN activity, which involves the direct interaction of NOX4 with PTEN. This study will provide new experimental evidences for clarifying the mechanisms for enhanced aerobic glycolysis in NSCLC and contribute to development of effective targets to reverse NSCLC malignant progression.

NOX与肿瘤恶性进展密切相关，但机制未明。我们工作发现NOX4在非小细胞肺癌（NSCLC）中表达量与临床分期存在正相关性；NOX4可通过抑制PTEN活性促进NSCLC细胞增殖及侵袭，其抑制PTEN活性的效应部分依赖其产生ROS。有氧糖酵解在肿瘤恶性进展中发挥重要作用，我们发现抑制糖酵解可明显逆转NOX4促进NSCLC细胞增殖和侵袭的效应，提示NOX4可能通过增强有氧糖酵解来促进NSCLC增殖转移。目前已知：PTEN功能降低在调控肿瘤细胞有氧糖酵解中发挥关键作用。综上，我们提出如下假设：NOX4通过抑制PTEN活性增强癌细胞有氧糖酵解，从而促进NSCLC恶性进展，并拟在不同水平上充分证实这一假设。此外，基于前期结果，我们首次提出NOX4抑制PTEN活性的一个新的可能机制：通过直接与PTEN相互作用。本研究为阐明NSCLC有氧糖酵解增强的机制、探索有效的靶点来逆转其恶性进展提供新的实验依据。

NADPH氧化酶（NOXs）及其催化产生的ROS是促进肿瘤恶性进展的重要因素，然而其机制仍未阐明。糖代谢异常是肿瘤细胞的一个重要特征。肿瘤细胞无论氧气供应充足与否都主要依赖糖酵解进行代谢，消耗大量葡萄糖获得能量，并伴有乳酸的生成，这一现象被称之为有氧糖酵解。有氧糖酵解赋予肿瘤细胞生长优势，但其形成及增强的机制至今未明。本研究在以往工作基础上提出“NOX4通过增强非小细胞肺癌（NSCLC）有氧糖酵解促进其恶性进展”这一研究假设，围绕NOX4在NSCLC细胞增殖和糖代谢中的功能和分子机制，进行了系统和创新研究。体内外实验结果表明NOX4可促进癌细胞增殖，并可促进葡萄糖消耗、ATP生成及乳酸生成；NOX4抑制剂GKT137831可明显抑制体内瘤体生长，并能与糖酵解抑制剂2-DG协同抑制瘤体生长。机制研究结果表明干扰NOX4表达可明显抑制NSCLC细胞内转录因子c-Myc的表达量；过表达NOX4可上调细胞内c-Myc的表达量，此效应可被PI3K/Akt信号抑制剂LY294002阻断。干扰c-Myc表达可抑制细胞糖消耗，此时再干扰NOX4不再产生额外抑制糖消耗效应。上述结果表明NOX4通过激活PI3K/Akt信号促进NSCLC细胞有氧糖酵解。本研究为阐明NSCLC细胞有氧糖酵解形成及增强的机制、并为临床制定针对氧化应激抗NSCLC策略提供实验基础。..