Development of Human Asparaginase for Cancer Therapy

项目摘要： 本申请将解决成人急性脑梗死患者对上级治疗结局的未满足需求。 淋巴细胞白血病（ALL），并将开发个性化治疗所需的工具，以允许更多的 一种名为L-天冬酰胺酶的独特抗癌药物的广泛使用。与儿科ALL不同， 治愈率> 90%，成人ALL治愈率<40%。一个显著的区别是， 儿科和成人ALL患者的区别在于，只有儿科方案总是包括药物L-天冬酰胺酶。 事实上，它表明，治愈率是高度依赖于使用这种药物，并为病人能够 完成整个疗程。不幸的是，L-天冬酰胺酶治疗的副作用通常需要 提前停止使用这种药物。 这些L-天冬酰胺酶的副作用可以直接追溯到细菌的起源和所有电流的性质。 FDA批准的L-天冬酰胺酶（而不是抗癌药物的天冬酰胺消耗作用）。被 细菌酶，目前批准的药物是高度免疫原性的。尽管这种临床的一部分 这个问题最近已经通过聚乙二醇化酶来解决，酶是副作用的另一个来源，L- 这些细菌酶的转氨酶共同活性仍然存在。我们提出一项战略， 免疫原性和L-丙氨酸氨基转移酶相关的副作用，其中细菌酶被替换为 缺乏L-天冬酰胺酶共活性的人样L-天冬酰胺酶。 生物制品与人类序列越相似，其免疫原性就越小。在我们的工作中， 迄今为止，我们鉴定了一种哺乳动物L-天冬酰胺酶（称为gpASNas 1），其与人的70%相同 酶（相比之下，细菌酶的同一性仅为25%），我们已经增加了， 通过采用遗传筛选和结构信息，将同一性百分比提高到85%。在我们提出的工作中 在这里，我们已经确定了将该百分比同一性增加到> 95%的路径。同样重要的是，gpASNase 1是 没有引起毒性的L-丙氨酸氨基转移酶活性，因此作为一种药物，它也没有那些副作用， 是由谷氨酰胺缺乏引起的重要的是，在人类T-ALL和B-ALL的小鼠异种移植模型中，我们 观察到这些类人L-天冬酰胺酶药物的有效抗癌作用，这证明了 L-丙氨酸氨基转移酶活性不是杀死癌细胞所必需的。此外，与L- 含有FDA药物的天冬酰胺酶，我们的没有这种共活性的L-天冬酰胺酶版本表现出降低的 毒性因此，L-天冬酰胺酶变体，将开发的拟议工作将有很高的影响 所有治疗，特别是对成年人，因此与退伍军人特别相关。 除了影响ALL治疗外，我们的愿景是将L-天冬酰胺酶的使用扩展到其他领域。 恶性肿瘤。目前阻碍L-天冬酰胺酶扩大使用的主要因素（除了 上述副作用，将大大减少我们的变种）是缺乏一种方法来识别 最能从这种药物中获益的患者。为了弥补这一缺陷并促进个性化 在医学上，我们将首先确定决定癌细胞是否对L- 天冬酰胺酶，然后使用这种理解来开发L-天冬酰胺酶的预测筛选。 这项工作的成功将是革命性的，因为它将扩大L-天冬酰胺酶的使用范围， 对于其他血癌，通过联合使用更安全的药物（免疫原性更低， 缺乏L-丙氨酸氨基转移酶共活性）与可以预测患者对该药物的反应的伴随生物标志物。

Project Summary: This application will address the unmet need for superior treatment outcomes for adults with acute lymphoblastic leukemia (ALL), and will develop the tools needed for personalized treatment to allow a more expanded use of the unique anti-cancer drug called L-asparaginase. Unlike pediatric ALL, a disease with a cure rate of >90%, the cure rate of adult ALL is <40%. One significant difference between the treatment of pediatric and adult ALL patients is that only the pediatric regimen always includes the drug L-asparaginase. Indeed, it was shown that cure rates are highly dependent on using this drug, and for the patient being able to complete the full course of treatment. Unfortunately, the side effects of L-asparaginase treatment often require prematurely stopping use of this drug. These L-asparaginase side effects can be traced directly to the bacterial origin and properties of all current FDA-approved L-asparaginases (and not to the anti-cancer asparagine depletion effect of drug). Being bacterial enzymes, currently approved drugs are highly immunogenic. Although a portion of this clinical problem has recently been addressed by pegylating the enzyme, the other source of side effects, the L- glutaminase co-activity of these bacterial enzymes, still remains. We propose a strategy that would address both the immunogenic and L-glutaminase-related side effects, in which the bacterial enzymes are replaced by human-like L-asparaginases that are devoid of L-glutaminase co-activity. The more similar a biologic is to a human sequence, the less likely it would be immunogenic. In our work to date, we identified a mammalian L-asparaginase (referred to as gpASNas1) that is 70% identical to the human enzyme (as compared to the mere 25% identity of the bacterial enzymes), and we have increased that percentage identity to 85% by employing a genetic screen and structural information. In our proposed work here, we have identified a path that will increase this percent identity to >95%. As importantly, gpASNase1 is devoid of the toxicity-causing L-glutaminase activity, so as a drug, it will also lack those side effects that are caused by glutamine depletion. Critically, in a mouse xenograft model of human T-ALL and B-ALL, we observed a potent anti-cancer effect of these human-like L-asparaginase drugs, which serves to demonstrate that the L-glutaminase activity is not required for killing the cancer cells. Moreover, as compared to the L- glutaminase containing FDA drug, our L-asparaginase version without this co-activity has exhibited reduced toxicity. Thus, the L-asparaginase variant that will be developed by the proposed work will have a high impact on ALL therapy, especially for adults, and thus with special relevance for veterans. In addition to impacting ALL treatment, our vision is to expand the use of L-asparaginases to other malignancies. A main factor that currently prevents the expanded use of L-asparaginases (in addition to aforementioned side effects that will be largely reduced by our variants) is the lack of a method to identity patients who would most benefit from this drug. To remedy this deficiency and to promote personalizing medicine, we will first identify the factors that determine whether a cancer cell is sensitive or resistant to L- asparaginase, and then use this understanding to develop a predictive screen for L-asparaginase. Success in the proposed work will be transformative, as it will expand the use of L-asparaginases beyond ALL to other blood cancers, through the combination of a drug that is safer (by being less immunogenic and by lacking L-glutaminase co-activity) with a companion biomarker that can predict a patient's response to this drug.