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学疗法，但在低级B细胞NHL患者的存活中几乎没有发现任何改善。利妥昔单抗，一种抗CD20 mAb可诱导50-60％的卵泡NHL患者的恢复。作用机理尚不清楚，但可能包括通过抗体依赖性细胞介导的细胞毒性（ADCC）赋予人IgG1常数区域的增强免疫效应器机制。但是，我们观察到1）只有50％的患者反应，而2）只有40％的最初反应患者对重新治疗的反应，3）没有预测反应的免疫功能的相关性，4）初步数据表明，与某些人类肿瘤细胞上的抗体在某些人类肿瘤细胞上的抗体对抗体的直接抗增殖作用比其他直接的效果更大，而5）则与其他蚂蚁相比，其他抗体对其他蚂蚁的影响更大。我们假设这些直接影响对这种MAB（增殖和凋亡的诱导块）是造成治疗作用的原因，并且这些直接作用的丧失有助于获得的抗性。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，然后确定这些作用是否存在或不存在这些作用预测临床活性。该提案的目的是：I。通过评估对（a）细胞增殖和凋亡的影响，对B细胞淋巴瘤线中诱导的细胞信号的早期事件的替代度量； （b）将CD20抗原重新分布为不溶性膜分数； （C）通过SRC家族激酶通过SRC家族激酶的酪氨酸磷酸化； （d）动员钙； （e）Bcl-2家族蛋白的表达/调节。 ii。评估用利妥昔单抗治疗的这些细胞信号事件的患者的原代NHL细胞，并与观察到的临床敏感性或耐药性发展相关。 （a）对早期利妥昔单抗临床试验的冷冻保存的NHL细胞的分析； （b）对FHCRC方案＃1344患者的肿瘤活检的前瞻性分析。 iii。确定MAB FC区域在NOD/SCID小鼠中B细胞NHL系的异种移植物中抗CD20 mAb的抗增殖作用中的作用。