Arginine Deprivation: A targeted therapy for Melanoma

精氨酸剥夺：黑色素瘤的靶向治疗

• 批准号: 6930470
• 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/6930470
• 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治疗具有抗药性，而药物治疗历来是非选择性的，并且通常具有很强的毒性。一种新方法是针对黑色素瘤细胞中发现的特定缺陷。我们和其他人已经证明，黑色素瘤细胞暴露于精氨酸脱亚胺酶（ADI）（一种催化精氨酸水解为瓜氨酸的酶）会导致细胞凋亡。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，不表达精氨酸琥珀酸合成酶 (ASS)，因此无法合成精氨酸。 ASS cDNA 的转染赋予了对 AD1 的抗性，进一步证实了 ASS 表达的缺乏对于 ADI 敏感性至关重要。我们配制了聚乙二醇化形式的 ADI (ADI-PEG20)，以降低免疫原性并延长半衰期。 ADI-PEG20在体内表现出显着的抗肿瘤活性且毒性低。我们已经完成了 ADI-PEG20 治疗晚期黑色素瘤的 I 期试验。值得注意的是，当治疗剂量 >160 IU/m2 时，5/10 的患者出现部分缓解，该剂量将血浆精氨酸消耗至不可检测的水平，持续时间 > 7 天。未观察到 > 2 级毒性。有趣的是，两名没有反应的患者的肿瘤中有 ASS 表达。在本申请中，我们计划进行一项 II 期试验，以确认晚期黑色素瘤的抗肿瘤活性，如具体目标 1 中所述。在具体目标 2 中，我们将在治疗前后通过免疫组织化学和 RT-PCR 检测肿瘤样本中的 ASS，以评估 ASS 表达是否可以作为肿瘤反应的预测因子，以及复发时 ASS 的去抑制是否发生。在具体目标3中，我们将研究ADI-PEG20导致细胞凋亡的可能机制。此外，将通过使用对 ADI-PEG20 具有抗性的体外细胞系以及使用在治疗失败时源自肿瘤的从头抗性细胞系来检查可能的抗性机制。为了优化 ADI-PEG20 的未来使用，我们将研究药物操作是否可以诱导/抑制 ASS 表达。我们的目标是通过针对黑色素瘤细胞的特定缺陷来改善黑色素瘤的治疗结果，同时最大限度地减少毒性。