Arginine Deprivation: A targeted therapy for Melanoma

精氨酸剥夺：黑色素瘤的靶向治疗

• 批准号: 6816878
• 负责人: LYNN G FEUN
• 金额: $ 20.45万
• 依托单位: UNIVERSITY OF MIAMI SCHOOL OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-08-06 至 2007-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6816878
• 关键词: amidinohydrolase; antineoplastics; apoptosis; arginine; carbon nitrogen ligase; clinical research; clinical trial phase II; combination chemotherapy; drug resistance; drug screening /evaluation; enzyme activity; gene expression; human subject; human therapy evaluation; immunocytochemistry; melanoma; neoplasm /cancer chemotherapy; neoplasm /cancer classification /staging; neoplasm /cancer pharmacology; neoplasm /cancer relapse /recurrence; neoplastic cell; patient oriented research; polyethylene glycols; polymerase chain reaction; prognosis

DESCRIPTION (provided by applicant): Malignant melanoma is usually resistant to drug therapy which historically has been non-selective in action and often very toxic. A novel approach is to target a specific defect found in melanoma cells. We and others have shown that exposure of melanoma cells to arginine deiminase (ADI), an enzyme that catalyzes the hydrolysis of arginine to citrulline, results in apoptotic cell death. This unique sensitivity to ADI is primarily due to the fact that melanoma cells, unlike normal cells, do not express argininosuccinate synthetase (ASS) and hence are unable to synthesize arginine. Transfection of ASS cDNA confers resistance to AD1, further confirming that lack of ASS expression is critical for ADI sensitivity. We formulated a pegylated form of ADI (ADI-PEG20) to reduce immunogenicity and to increase the half-life. ADI-PEG20 has shown significant antitumor activity in vivo with low toxicity. We have completed a Phase I trial of ADI-PEG20 in advanced melanoma. Remarkably, 5/10 patients had partial response when treated at a dose >160 IU/m2, a dose that depleted plasma arginine to non detectable levels for >7 days. No > grade 2 toxicity was observed. Interestingly, two patients who did not respond had ASS expression in their tumors. In this application, we plan to conduct a Phase II trial to confirm the antitumor activity in advanced melanoma as outlined in specific aim 1. In specific aim 2, we will assay ASS in tumor samples by immunohistochemistry and RT-PCR prior and after treatment to assess whether ASS expression can be a predictor for tumor response, and whether de-repression of ASS occurs at relapse. In specific aim 3, we will investigate the possible mechanism of apoptotic cell death by ADI-PEG20. In addition, the possible mechanism(s) of resistance will be examined by using an in-vitro cell line made resistant to ADI-PEG20 and by using de-novo resistant cell lines derived from tumors at time of treatment failure. In order to optimize future use of ADI-PEG20, we will investigate whether pharmacological manipulation can induce/repress ASS expression. Our goal is to improve the treatment outcome of melanoma while minimizing toxicity by targeting a specific defect in melanoma cells.

描述（由申请人提供）：恶性黑色素瘤通常对药物疗法具有抵抗力，这在历史上一直是无效的，而且通常非常毒性。一种新的方法是靶向黑色素瘤细胞中发现的特定缺陷。我们和其他人已经表明，黑色素细胞暴露于精氨酸脱节酶（ADI），这是一种促催化精氨酸水解为瓜氨酸的酶，导致凋亡细胞死亡。这种对ADI的独特敏感性主要是由于黑色素瘤细胞与正常细胞不同，不会表达精氨酸偶联的合成酶（ASS），因此无法合成精氨酸。屁股cDNA的转染赋予对AD1的抗性，进一步证实缺乏屁股表达对于ADI敏感性至关重要。我们制定了ADI（ADI-PEG20）的类化形式，以降低免疫原性并增加半衰期。 ADI-PEG20在体内显示出明显的抗肿瘤活性，毒性低。我们已经完成了晚期黑色素瘤中ADI-PEG20的I期试验。值得注意的是，在剂量> 160 IU/m2治疗时，有5/10例患者有部分反应，这是一种将血浆精氨酸耗尽至不可检测水平的剂量> 7天。没有观察到> 2级毒性。有趣的是，两名未反应的患者在肿瘤中表达了屁股。在此应用中，我们计划进行II期试验，以确认特定目标1中概述的晚期黑色素瘤中的抗肿瘤活性。在特定的目标2中，我们将通过免疫组织化学和治疗后通过免疫组织化学和RT-PCR在肿瘤样本中测定ASS，以评估ASS表达是否可以预测肿瘤的反应，以及在相互降解时是否会进行抑制作用。在特定目标3中，我们将研究ADI-PEG20的凋亡细胞死亡的可能机制。此外，将使用对ADI-PEG20具有抗性的体外细胞系以及在治疗失败时使用肿瘤衍生的De-Novo抗性细胞系来检查耐药性的可能机制。为了优化ADI-PEG20的未来使用，我们将研究药理操作是否可以诱导/抑制ASS表达。我们的目标是改善黑色素瘤的治疗结果，同时通过靶向黑色素瘤细胞的特定缺陷来最大程度地减少毒性。