State Key Laboratory of Biotherapy and Cancer Center/Collaborative Innovation Center for Biotherapy, West China Hospital, Sichuan University, Chengdu, PR China.
State Key Laboratory of Biotherapy and Cancer Center/Collaborative Innovation Center for Biotherapy, West China Hospital, Sichuan University, Chengdu, PR China; West China School of Public Health and West China Fourth Hospital, Healthy Food Evaluation Research Center/ Sichuan University, Chengdu, PR China.
Eur J Med Chem. 2020 Aug 1;199:112364. doi: 10.1016/j.ejmech.2020.112364. Epub 2020 Apr 30.
Cryptophycin-52 (CR52), a tubulin inhibitor, exhibits promising antitumor activity in vitro (picomolar level) and in mouse xenograft models. However, the narrow therapeutic window in clinical trials limits its further development. Antibody-drug conjugate (ADC), formed by coupling cytotoxic compound (payload) to an antibody via a linker, can deliver drug to tumor locations in a targeted manner by antibody, enhancing the therapeutic effects and reducing toxic and side effects. In this study, we aim to explore the possibility of CR52-based ADC for tumor targeted therapy. Due to the lack of a coupling site in CR52, its prodrug cryptophycin-55 (CR55) containing a free hydroxyl was synthesized and conjugated to the model antibody trastuzumab (anti-HER2 antibody drug approved by FDA for breast cancer therapy) via the linkers based on Mc-NHS and Mc-Val-Cit-PAB-PNP. The average drug-to-antibody ratios (DARs) of trastuzumab-CR55 conjugates (named T-L1-CR55, T-L2-CR55, and T-L3-CR55) were 3.50, 3.29, and 3.35, respectively. These conjugates exhibited potent cytotoxicity in HER2-positive tumor cell lines with IC values at low nanomolar levels (0.58-1.19 nM). Further, they displayed significant antitumor activities at the doses of 10 mg/kg in established ovarian cancer (SKOV3) and gastric cancer (NCI-N87) xenograft models without overt toxicities. Finally, the drug releases were analyzed and the results indicated that T-L3-CR55 was able to effectively release CR55 and further epoxidized to CR52, which may be responsible for its best performance in antitumor activities. In conclusion, our results demonstrated that these conjugates have the potential for tumor targeted therapy, which provides insights to further research the CR55/CR52-based ADC for tumor therapy.
隐色霉素 52（CR52）是一种微管抑制剂，在体外（皮摩尔水平）和小鼠异种移植模型中表现出有希望的抗肿瘤活性。然而，临床试验中的治疗窗狭窄限制了其进一步发展。抗体药物偶联物（ADC）是通过连接子将细胞毒性化合物（有效载荷）偶联到抗体上形成的，可以通过抗体将药物靶向递送至肿瘤部位，从而增强治疗效果，降低毒性和副作用。在这项研究中，我们旨在探索基于 CR52 的 ADC 用于肿瘤靶向治疗的可能性。由于 CR52 缺乏偶联位点，因此合成了含有游离羟基的前药隐色霉素 55（CR55），并通过基于 Mc-NHS 和 Mc-Val-Cit-PAB-PNP 的连接子将其偶联到模型抗体曲妥珠单抗（美国食品和药物管理局批准用于乳腺癌治疗的抗 HER2 抗体药物）上。曲妥珠单抗-CR55 缀合物（命名为 T-L1-CR55、T-L2-CR55 和 T-L3-CR55）的平均药物抗体比（DAR）分别为 3.50、3.29 和 3.35。这些缀合物在 HER2 阳性肿瘤细胞系中表现出强大的细胞毒性，IC 值在低纳摩尔水平（0.58-1.19 nM）。此外，它们在已建立的卵巢癌（SKOV3）和胃癌（NCI-N87）异种移植模型中以 10 mg/kg 的剂量显示出显著的抗肿瘤活性，且无明显毒性。最后，分析了药物释放情况，结果表明 T-L3-CR55 能够有效地释放 CR55，并进一步环氧化为 CR52，这可能是其在抗肿瘤活性方面表现最佳的原因。总之，我们的结果表明这些缀合物具有肿瘤靶向治疗的潜力，为进一步研究基于 CR55/CR52 的 ADC 用于肿瘤治疗提供了思路。
