PO.IM01.03 · 免疫学
靶向IGF1R的疫苗在同基因小鼠结肠癌模型中诱导中和抗体和强效抗肿瘤活性
Vaccine targeting IGF1R induces neutralizing antibody and robust anti-tumor activity in a syngeneic mouse colon cancer model
作者与单位 Authors & Affiliations
摘要 Abstract
中文摘要
背景：胰岛素样生长因子（IGF）及其受体（IGF1R）诱导重要的细胞信号传导，调节细胞增殖、存活和代谢。IGF1R在癌症中的过表达与不良预后及对常规疗法的耐药性相关，凸显了对创新治疗策略的需求。在本研究中，我们开发了IGF1R疫苗候选物，并在同基因小鼠结肠癌模型中评估了其抗肿瘤活性。
方法：制备了重组蛋白，其包含不同的免疫增强剂以及位于参与IGF-IGF1R配体-受体相互作用区域内的计算预测B细胞表位，旨在诱导阻断IGF-IGF1R相互作用的抗体。在C57BL/6小鼠中评估疫苗蛋白的免疫原性，于第0、14、28、42、49和56天使用以CpG ODN 1826和AS03佐剂化的蛋白进行6次疫苗接种。在多个时间点采集血清样本，通过ELISA测定anti-IGF1R抗体滴度，并通过竞争性ELISA经阻断IGF1与IGF1R结合来测定体外中和活性。在C57BL/6小鼠的同基因MC38小鼠结肠癌模型中评估疫苗的抗肿瘤疗效，这些小鼠在最后一次接种一周后经皮下接种MC38细胞。仅给予佐剂的小鼠用作对照。每周记录两次肿瘤生长直至终点。
结果：IGF1R疫苗诱导了强效的体液免疫应答，高滴度的anti-IGF1R抗体即为证明。重要的是，从接种小鼠采集的血清样本表现出强中和活性，在竞争性ELISA中抑制IGF1与IGF1R结合达68%。诱导最高抗体滴度（即1:125,000）的两种蛋白进一步评估了其抗肿瘤疗效。在使用MC38模型的抗肿瘤研究中，这两种IGF1R疫苗在研究终点相较于对照分别抑制肿瘤生长62%和61%（p<0.01）。
结论：总之，这些发现确立了概念验证，即靶向IGF1R的疫苗能够引发阻断IGF1与IGF1R结合的中和抗体，从而抑制IGF/IGF1R信号发挥关键作用的肿瘤的生长。这一结果支持进一步研究和优化这些IGF1R疫苗，以治疗依赖IGF/IGF1R信号的癌症。
查看英文原文 English abstract
Background Insulin-like growth factors (IGFs) and their receptor (IGF1R) induce important cellular signalling that regulates cell proliferation, survival, and metabolism. Overexpression of IGF1R in cancers is associated with poor prognosis and resistance to conventional therapies, highlighting the need for innovative therapeutic strategy. In this study, we developed IGF1R vaccine candidates and evaluated their anti-tumor activity in a syngeneic mouse colon cancer model.
Methods Recombinant proteins comprising different immune enhancers and computationally-predicted B-cell epitopes in the regions involved in IGF-IGF1R ligand-receptor interaction, intended to induce antibodies to block IGF-IGF1R interaction, were produced. Immunogenicity of the vaccine proteins was assessed in C57BL/6 mice by vaccination 6 times on days 0, 14, 28, 42, 49 and 56 using the proteins adjuvanted with CpG ODN 1826 and AS03. Serum samples were collected at multiple time points for determining anti-IGF1R antibody titers using ELISA as well as in vitro neutralization activity via blocking IGF1 binding to IGF1R using competitive ELISA. Anti-tumor efficacy of the vaccines was evaluated in a syngeneic MC38 mouse colon cancer model in C57BL/6 mice, which were vaccinated and inoculated subcutaneously with MC38 cells a week after the last vaccination. Mice administered adjuvant only were used as controls. Tumor growth was recorded twice a week till the end point.
Results IGF1R vaccines induced robust humoral immune response as demonstrated by high titer of anti-IGF1R antibody. Importantly, serum samples collected from vaccinated mice demonstrated strong neutralizing activity, inhibiting IGF1 binding to IGF1R by up to 68% in a competitive ELISA. Two proteins which induced the highest antibody titer (i.e. 1:125,000) were further evaluated for their anti-tumor efficacy. In the anti-tumor study using the MC38 model, these two IGF1R vaccines suppressed the growth of tumors by 62% and 61%, respectively, at the study endpoint compared to controls ( p <0.01).
Conclusions In summary, these findings establish proof-of-concept that IGF1R-targeting vaccines can elicit neutralizing antibodies that block IGF1 binding to IGF1R, thereby inhibiting the growth of tumors where IGF/IGF1R signalling plays critical roles. This result supports further investigation and optimization to improve these IGF1R vaccines to treat cancers dependent on IGF/IGF1R signalling.
利益披露 Disclosure
K. Lin, None..
M. Toh, None..
H. Wang, None.