MDA-7/IL-24 and free radicals in renal cancer therapy

MDA-7/IL-24 和自由基在肾癌治疗中的作用

• 批准号: 6988368
• 负责人: PAUL DENT
• 金额: $ 29.43万
• 依托单位: VIRGINIA COMMONWEALTH UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-09-01 至 2010-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6988368
• 关键词: apoptosis; arsenic; biological signal transduction; cell line; chimeric proteins; combination therapy; cytotoxicity; enzyme activity; free radical oxygen; free radicals; laboratory rat; mitogen activated protein kinase; protein purification; protein structure function; renal cell carcinoma; tumor suppressor proteins; western blottings

DESCRIPTION (provided by applicant): Renal Cell Carcinoma (RCC) is among the most lethal and difficult tumors to treat, particularly when disease has spread beyond the kidney and into the surrounding fascia; even intensive combinations of radio- and chemotherapy are not curative and yield only a modest impact on patient survival. There is a major need for alternative therapeutic modalities. Expression of MDA-7/IL-24 in many different tumor cell types causes growth arrest and apoptosis whereas in non-transformed cells it alters neither cell growth nor cell survival. Previous studies have shown that MDA-7 administered either as a virus (Ad.mda-7), as a purified fusion protein (GST-MDA-7), or in conditioned media, suppressed the growth of tumor cells. In RCC we found that low concentrations of MDA-7 (0.5-1.5 nM) suppressed growth without killing cells whereas higher levels of MDA-7 (> 20 nM) suppressed growth and enhanced cell death. Low levels of MDA-7 enhanced the sensitivity of RCCs to several agents that generate free radicals. The anti-proliferative and cytotoxic effects of MDA-7 and free radicals were not observed in primary renal cells. The mechanisms by which MDA-7 inhibits RCC proliferation and interacts with free radicals to kill RCCs are not fully understood. Specific aim 1 will determine whether GST-MDA-7, in a dose-dependent fashion, causes increasing amounts of p38 MAPK activation and JNK1/2 activation, in RCCs, whose signaling is believed to be responsible for cytokine-induced apoptosis at high (> 30 nM) GST-MDA-7 concentrations. Additionally, we will prove or refute whether [arsenic trioxide (As2O3) and N-(4-hydroxyphenyl) retinamide (4-HPR)], agents that generate reactive oxygen species, enhance the ability of low GST-MDA-7 concentrations (0.5-1.5 nM) to cause prolonged activation of the p38 and JNK1/2 pathways. Specific aim 2 will determine the mechanisms by which combined treatment of RCCs with PI3 kinase and MEK1/2 inhibitors enhance cell killing by purified MDA-7 protein. Additionally, we will prove or refute whether [arsenic trioxide (As2O3) and N-(4-hydroxyphenyl) retinamide (4-HPR)], agents that generate reactive oxygen species, enhance the lethality of low GST-MDA-7 concentrations by causing inactivation of ERK1/2. Specific aim 3 will determine whether infusion of Ad.mda-7 or MDA-7 protein, into a pre-existing tumor, reduces RCC growth and enhances tumor sensitivity to As2O3 and 4-HPR.

描述（由申请人提供）：肾细胞癌（RCC）是最致命和最难治疗的肿瘤之一，特别是当疾病扩散到肾脏外并进入周围筋膜时；即使是高强度的放化疗联合治疗也不能治愈，而且对患者生存的影响也不大。对替代治疗方式的需求很大。MDA-7/IL-24在许多不同肿瘤细胞类型中的表达导致生长停滞和凋亡，而在非转化细胞中，它既不改变细胞生长也不改变细胞存活。先前的研究表明，MDA-7可以作为一种病毒(Ad。作为纯化的融合蛋白（GST-MDA-7），或在条件培养基中，抑制肿瘤细胞的生长。在RCC中，我们发现低浓度的MDA-7 （0.5-1.5 nM）抑制生长而不杀死细胞，而高浓度的MDA-7 （bbb20 nM）抑制生长并促进细胞死亡。低水平的MDA-7增强了rcc对几种产生自由基的药物的敏感性。MDA-7和自由基在原代肾细胞中未观察到抗增殖和细胞毒作用。MDA-7抑制RCC增殖并与自由基相互作用杀死RCC的机制尚不完全清楚。特异性目的1将确定GST-MDA-7是否以剂量依赖性的方式引起rcc中p38 MAPK激活和JNK1/2激活的增加，其信号被认为是在高（bbb30 nM） GST-MDA-7浓度下细胞因子诱导的凋亡的原因。此外，我们将证明或驳斥三氧化二砷（As2O3）和N-（4-羟基苯基）维甲酸（4-HPR）这两种产生活性氧的物质是否能增强低GST-MDA-7浓度（0.5-1.5 nM）导致p38和JNK1/2通路延长激活的能力。特异性目的2将确定rcc与PI3激酶和MEK1/2抑制剂联合治疗的机制，通过纯化的MDA-7蛋白增强细胞杀伤。此外，我们将证明或驳斥[三氧化二砷（As2O3）和N-（4-羟基苯基）视黄酰胺（4-HPR）]这两种产生活性氧的物质是否通过引起ERK1/2失活来增强低GST-MDA-7浓度的致病性。特异性目的3将决定是否输注Ad。将mda-7或mda-7蛋白注入已存在的肿瘤，可降低RCC的生长并增强肿瘤对As2O3和4-HPR的敏感性。