Marini P, Denzinger S, Schiller D, Kauder S, Welz S, Humphreys R, Daniel P T, Jendrossek V, Budach W, Belka C
CCC Tübingen, Department of Radiation Oncology, University of Tübingen, Tübingen, Germany.
Oncogene. 2006 Aug 24;25(37):5145-54. doi: 10.1038/sj.onc.1209516. Epub 2006 Apr 24.
We and others have demonstrated already that TRAIL (TNF-related apoptosis-inducing ligand) is a very promising candidate for molecular targeted anticancer therapy, especially when combined with ionizing radiation or other DNA-damaging agents. Agonist monoclonal antibodies that activate and are specific for the death signaling TRAIL receptors are an alternative method to stimulate the programmed cell death pathway. Phase 1 clinical trials have subsequently been conducted and shown a very good tolerability of these antibodies. In order to assess the efficacy of TRAIL receptor stimulation to induce cell death by this alternate method, we studied the combination of the agonistic-TRAIL receptor antibodies HGS-ETR1 and HGS-ETR2 with radiation in vitro and in vivo. Induction of apoptosis after combined treatment with TRAIL receptor antibodies HGS-ETR1 and/or HGS-ETR2 (0.01, 0.1, 1.0 mg/ml) and irradiation with 2, 5 or 10 Gy was determined by fluorescence microscopy and Western blot analysis of caspase-8 and PARP. The colorectal tumour cell lines Colo 205, HCT 116 and HCT-15 were used for in vitro experiments. Growth delay experiments were performed with combined treatment with fractionated irradiation (days 1-5 and 3 Gy single dose/day) and the receptor antibodies (intraperitonially, three different concentrations, application on days 1, 4 and 8) on Colo 205 xenograft-bearing NMRI (nu/nu) nude mice. HGS-ETR1 and HGS-ETR2 induced apoptotic cell death in a dose-dependent fashion and significantly increased cell death in combination with irradiation in vitro when compared to either irradiation or antibody treatment alone. The efficacy of the combined treatment seems to be at least partially Bax-dependent. Similar to the results from cell culture experiments, in vivo experiments demonstrated a dose-dependent delay in tumour growth after combined treatment. In vivo, in the Colo205 xenograft model, HGS-ETR2 revealed a higher activity than HGS-ETR1. This is the first study to demonstrate significant efficacy of combined treatment with the monoclonal agonistic TRAIL receptor antibodies HGS-ETR1 and HGS-ETR2 and ionising radiation in in vitro and in vivo models. We postulate that HGS-ETR1 and HGS-ETR2 will be very promising new agents in the field of molecular targeted multi-modality anticancer therapy.
我们和其他研究团队已经证明，TRAIL（肿瘤坏死因子相关凋亡诱导配体）是分子靶向抗癌治疗中一个非常有前景的候选药物，尤其是与电离辐射或其他DNA损伤剂联合使用时。激活死亡信号TRAIL受体且具有特异性的激动剂单克隆抗体是刺激程序性细胞死亡途径的另一种方法。随后进行了1期临床试验，结果显示这些抗体具有很好的耐受性。为了评估通过这种替代方法刺激TRAIL受体诱导细胞死亡的疗效，我们在体外和体内研究了激动型TRAIL受体抗体HGS - ETR1和HGS - ETR2与辐射的联合作用。通过荧光显微镜以及对caspase - 8和PARP进行蛋白质免疫印迹分析，确定了用TRAIL受体抗体HGS - ETR1和/或HGS - ETR2（0.01、0.1、1.0 mg/ml）与2、5或10 Gy照射联合处理后细胞凋亡的诱导情况。结直肠肿瘤细胞系Colo 205、HCT 116和HCT - 15用于体外实验。在携带Colo 205异种移植瘤的NMRI（nu/nu）裸鼠上进行了分次照射（第1 - 5天，每天单次剂量3 Gy）与受体抗体（腹腔内注射，三种不同浓度，在第1、4和8天给药）联合治疗的生长延迟实验。HGS - ETR1和HGS - ETR2以剂量依赖的方式诱导凋亡性细胞死亡，与单独照射或抗体治疗相比，在体外与辐射联合使用时显著增加了细胞死亡。联合治疗的疗效似乎至少部分依赖于Bax。与细胞培养实验结果相似，体内实验表明联合治疗后肿瘤生长出现剂量依赖性延迟。在体内，在Colo205异种移植模型中，HGS - ETR2显示出比HGS - ETR1更高的活性。这是第一项证明在体外和体内模型中，单克隆激动型TRAIL受体抗体HGS - ETR1和HGS - ETR2与电离辐射联合治疗具有显著疗效的研究。我们推测HGS - ETR1和HGS - ETR2将成为分子靶向多模态抗癌治疗领域非常有前景的新型药物。
