ANTI-CD20 ANTIBODY THERAPY OF NHL-- MECHANISM OF ACTION

NHL的抗CD20抗体治疗——作用机制

• 批准号: 6027185
• 负责人: DAVID G MALONEY
• 金额: $ 25.28万
• 依托单位: FRED HUTCHINSON CANCER RESEARCH CENTER
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-12-27 至 2002-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6027185
• 关键词: B lymphocyte; CD antigens; NOD mouse; SCID mouse; apoptosis; biological signal transduction; calcium flux; cell proliferation; clinical research; drug resistance; drug screening /evaluation; gene expression; human subject; human therapy evaluation; immunoglobulin structure; monoclonal antibody; neoplasm /cancer immunology; neoplasm /cancer immunotherapy; nonHodgkin's lymphoma; oncoproteins; pharmacokinetics; phosphorylation; protein structure function; tissue /cell culture

Despite active chemotherapy, virtually no improvement has been observed in the survival of patients with low grade B cell NHL. Rituximab, a anti-CD20 mAb induces remissions in 50-60% of patients with follicular NHL. The mechanism of action is not known but likely includes augmented immune effector mechanisms through antibody dependent cell mediated cytotoxicity (ADCC) conferred by the human IgG1 constant region. However, we have observed 1) only 50% of patients respond, and 2) only 40% of initially responding patients respond to re-treatment, and 3) there are no correlates of immune function that predict response, and 4) preliminary data demonstrates direct anti- proliferative effects of the antibody in vitro on some human tumor cell lines, and 5) these direct effects are greater than that observed with other anti-CD20 mAbs. We hypothesize that these direct effects on this mAb (block of proliferation and induction of apoptosis) are responsible for the therapeutic effects and that the loss of these direct effects contributes to acquired resistance. We will therefore test our hypothesis by developing methods for testing the anti-proliferative effects of anti-CD20 antibody on primary human lymphoma cells and then determine whether the presence or absence of these effects predict clinical activity. The Aims of this proposal are to: I. Develop surrogate measures of early events in cell signaling induced in B cell lymphoma lines that are sensitive or resistant to in vitro anti-CD20 mediated effects by evaluating effect on (a) cell proliferation and apoptosis; (b) re-distribution of the CD20 antigen into a insoluble membrane fraction; (c) tyrosine phosphorylation through Src family kinases; (d) calcium mobilization; (e) expression/regulation of bcl-2 family proteins. II. Evaluate primary NHL cells from patients treated with Rituximab for these cell signaling events and correlate with observed clinical sensitivity or development of resistance. (a) analysis of cryopreserved NHL cells from earlier Rituximab clinical trials; (b) prospective analysis of tumor biopsies from patients on FHCRC protocol #1344. III. Determine the role of the mAb FC region in mediating anti- proliferative effects of anti-CD20 mAbs in xenografts of B cell NHL lines in NOD/SCID mice.

尽管进行了积极的化疗，但低度 B 细胞 NHL 患者的生存率几乎没有观察到任何改善。 Rituximab（利妥昔单抗）是一种抗 CD20 mAb，可诱导 50-60% 的滤泡性 NHL 患者病情缓解。其作用机制尚不清楚，但可能包括通过人 IgG1 恒定区赋予的抗体依赖性细胞介导的细胞毒性 (ADCC) 增强免疫效应机制。然而，我们观察到：1) 只有 50% 的患者有反应，2) 最初有反应的患者中只有 40% 对再治疗有反应，3) 没有预测反应的免疫功能相关因素，4) 初步数据表明该抗体在体外对某些人类肿瘤细胞系有直接的抗增殖作用，5) 这些直接作用比用其他抗 CD20 mAb 观察到的作用更大。我们假设这种单克隆抗体的这些直接作用（阻止增殖和诱导细胞凋亡）是产生治疗效果的原因，而这些直接作用的丧失会导致获得性耐药。因此，我们将通过开发测试抗CD20抗体对原代人淋巴瘤细胞的抗增殖作用的方法来检验我们的假设，然后确定这些作用的存在或不存在是否可以预测临床活性。该提案的目的是： I. 通过评估对 (a) 细胞增殖和凋亡的影响，开发对体外抗 CD20 介导的效应敏感或耐药的 B 细胞淋巴瘤系中诱导的细胞信号转导早期事件的替代测量； (b)将CD20抗原重新分配到不溶性膜部分中； (c) 通过 Src 家族激酶进行酪氨酸磷酸化； (d) 钙动员； (e) bcl-2家族蛋白的表达/调节。二.评估接受利妥昔单抗治疗的患者的原代 NHL 细胞的这些细胞信号转导事件，并与观察到的临床敏感性或耐药性的发展相关联。 (a) 对早期利妥昔单抗临床试验中冷冻保存的 NHL 细胞进行分析； (b) 对 FHCRC 方案 #1344 患者的肿瘤活检进行前瞻性分析。三．确定 mAb FC 区在介导 NOD/SCID 小鼠 B 细胞 NHL 系异种移植物中抗 CD20 mAb 的抗增殖作用中的作用。