抗CD20抗体（IDEC-C2B8，利妥昔单抗）在体外增强细胞毒性药物对肿瘤淋巴细胞的疗效：细胞因子、补体和半胱天冬酶的作用

Anti-CD20 antibody (IDEC-C2B8, rituximab) enhances efficacy of cytotoxic drugs on neoplastic lymphocytes in vitro: role of cytokines, complement, and caspases.

作者信息

Chow Kai U, Sommerlad Wolf Daniel, Boehrer Simone, Schneider Bernd, Seipelt Gernot, Rummel Mathias Johannes, Hoelzer Dieter, Mitrou Paris S, Weidmann Eckart

机构信息

University Hospital, Department of Internal Medicine III, Hematology and Oncology, Theodor-Stern-Kai 7, 60590 Frankfurt/Main, Germany.

出版信息

Haematologica. 2002 Jan;87(1):33-43.

PMID:11801463

Abstract

BACKGROUND AND OBJECTIVES

Monoclonal antibody IDEC-C2B8 (rituximab) has been shown to be highly effective in the treatment of non-Hodgkin's lymphomas (NHL). The present study was designed to investigate relationships between the efficacy of IDEC-C2B8 and expression of CD20, presence of complement, and effects of differently acting chemotherapeutic agents used in lymphoma treatment (doxorubicin, mitoxantrone, cladribine, bendamustine).

DESIGN AND METHODS

DOHH-2, WSU-NHL and Raji lymphoma cell lines and ex vivo cells from patients with chronic lymphocytic leukemia (CLL) (n=17) and leukemic B-cell lymphomas (n=9) were studied. Additionally, the effect of interleukin (IL)-2, IL-4, IL-6, IL-13, granulocyte/macrophage colony-stimulating factor (GM-CSF) and tumor necrosis factor (TNF)alpha on expression of CD20 molecules per cell was determined.

RESULTS

We demonstrate that 10 mg/mL rituximab saturated 80-95% of CD20 molecules per cell in all tested lymphoma samples. Although rituximab induced only a minor increase of apoptosis, combinations of rituximab with different cytotoxic drugs significantly decreased the IC(30)- and IC(50) dosages of the chemotherapeutic agents necessary for induction of apoptosis irrespective of addition of complement, demonstrating a chemosensitizing effect of rituximab in combination with cytotoxic drugs in the neoplastic lymphocytes. This effect seemed to be independent of the percentage of saturated CD20 molecules. After addition of caspase inhibitors to the cell lines incubated with rituximab and cytotoxic agents, caspase-7 and -8 were found, by Western blotting, to be the executioner caspases, possibly explaining the rituximab-sensitized apoptosis. Preincubation of lymphoma cells with cytokines did not alter the expression of CD20; IL-2 and IL-4 even decreased the rate of apoptosis.

INTERPRETATION AND CONCLUSIONS

We conclude that rituximab sensitizes lymphoma cells to the effect of differently acting cytotoxic drugs used in lymphoma treatment, that this effect does not require complement, and that caspase-7 and -8 may represent the main executioner caspases in chemosensitization by rituximab.

摘要

背景与目的

单克隆抗体IDEC-C2B8（利妥昔单抗）已被证明在治疗非霍奇金淋巴瘤（NHL）方面非常有效。本研究旨在探讨IDEC-C2B8的疗效与CD20表达、补体的存在以及淋巴瘤治疗中使用的不同作用机制的化疗药物（阿霉素、米托蒽醌、克拉屈滨、苯达莫司汀）的效果之间的关系。

设计与方法

研究了DOHH-2、WSU-NHL和Raji淋巴瘤细胞系以及慢性淋巴细胞白血病（CLL）患者（n = 17）和白血病性B细胞淋巴瘤患者（n = 9）的离体细胞。此外，还测定了白细胞介素（IL）-2、IL-4、IL-6、IL-13、粒细胞/巨噬细胞集落刺激因子（GM-CSF）和肿瘤坏死因子（TNF）α对每个细胞CD20分子表达的影响。

结果

我们证明，在所有测试的淋巴瘤样本中，10 mg/mL的利妥昔单抗可使每个细胞中80 - 95%的CD20分子饱和。尽管利妥昔单抗仅诱导轻微的凋亡增加，但利妥昔单抗与不同细胞毒性药物的联合使用显著降低了诱导凋亡所需的化疗药物的IC(30)和IC(50)剂量，无论是否添加补体，这表明利妥昔单抗与细胞毒性药物联合使用对肿瘤淋巴细胞具有化学增敏作用。这种作用似乎与饱和CD20分子的百分比无关。在用利妥昔单抗和细胞毒性药物孵育的细胞系中加入半胱天冬酶抑制剂后，通过蛋白质印迹法发现半胱天冬酶-7和-8是执行凋亡的半胱天冬酶，这可能解释了利妥昔单抗致敏的凋亡。用细胞因子对淋巴瘤细胞进行预孵育不会改变CD20的表达；IL-2和IL-4甚至降低了凋亡率。