PO.ET01.05 · 实验与分子治疗
新型高甘露糖聚糖靶向免疫疗法Avaren-Fc在卵巢癌中的抗肿瘤活性
Antitumor activity of Avaren-Fc, a novel high-mannose-glycan-targeting immunotherapy, in ovarian cancer
作者与单位 Authors & Affiliations
摘要 Abstract
中文摘要
卵巢癌(OVCA)是全球致死率最高、发病率第八的妇科癌症。目前的标准治疗缺乏肿瘤特异性,且无法有效控制耐药性疾病复发,凸显了对新型疗法的需求。Avaren-Fc(AvFc)是一种新型凝集素-Fc融合蛋白,旨在靶向异常的N-连接高甘露糖型聚糖——一种尚未充分利用的OVCA生物标志物。在与癌症相关的高甘露糖聚糖结合后,AvFc可激活Fcγ受体并诱导细胞毒性效应功能。我们此前的研究表明,在使用表达FcγRIIIa细胞系的体外荧光素酶ADCC报告基因检测中,AvFc可结合多种人OVCA细胞系(A2780、CAOV3、SKOV3和SW626)并诱导抗体依赖性细胞介导的细胞毒性(ADCC)活性。通过免疫组织化学检测,AvFc还可选择性识别I期高级别浆液性OVCA肿瘤而非邻近正常组织。在本研究中,我们使用鼠源ID8细胞系在体外实验以及C57BL/6小鼠的同基因原位攻击模型中评估了AvFc的抗OVCA活性。流式细胞术分析表明,AvFc以纳摩尔浓度剂量依赖性方式结合ID8细胞,而对分离的鼠源生殖细胞的结合可忽略不计。经I类α-甘露糖苷酶抑制剂kifunensine处理后,AvFc对ID8细胞的结合显著增加,而这种增强的结合在用内切糖苷酶H消化高甘露糖聚糖后被消除,证实了其高甘露糖依赖性。AvFc还通过激活FcγRIIIa诱导针对ID8细胞的替代性ADCC活性。在ID8 OVCA模型中评估了AvFc的抗肿瘤疗效,小鼠腹腔内(i.p.)接种2×10⁶个ID8细胞,并于攻击一周后开始接受15次AvFc给药(25 mg/kg,i.p.,每隔一天一次)、一种不结合糖的AvFc突变体或赋形剂治疗。与赋形剂对照相比,AvFc治疗显著延长了中位生存期,从46天延长至70天(校正p=0.0216,经Bonferroni校正的Log-rank[Mantel-Cox]检验)。在末次给药后一天进行的飞行时间质谱流式细胞术(CyTOF)分析显示,AvFc治疗独特地导致脾脏总白细胞扩增,包括Tbet+ Th1细胞,并使腹腔液中表达脱颗粒标志物CD107a的CD8+ T细胞增加,提示AvFc的抗癌疗效部分由适应性免疫介导。对ID8肿瘤的成像质谱流式细胞术分析正在进行中。综上所述,这些发现凸显了AvFc作为OVCA免疫治疗药物的良好潜力。
查看英文原文 English abstract
Ovarian cancer (OVCA) is the most lethal and eighth most common gynecological cancer worldwide. Current standard-of-care treatments lack tumor specificity and fail to effectively manage chemoresistant disease recurrence, highlighting the need for new therapeutics. Avaren-Fc (AvFc) is a novel lectin-Fc fusion protein designed to target aberrant N -linked high-mannose-type glycans, an underutilized OVCA biomarker. After binding to cancer-associated high-mannose glycans, AvFc can activate Fcgamma receptors and induce cytotoxic effector functions. Our previous work showed that AvFc binds to and induces antibody-dependent cell-mediated cytotoxicity (ADCC) activity against multiple human OVCA cells lines (A2780, CAOV3, SKOV3, and SW626) in an in vitro luciferase-based ADCC reporter assay using a FcgammaRIIIa-expressing cell line. AvFc also selectively recognized stage I high-grade serous OVCA tumors over adjacent normal tissue by immunohistochemistry. In the present study, we assessed the anti-OVCA activity of AvFc using the murine ID8 cell line in in vitro experiments and a syngeneic orthotopic challenge model in C57BL/6 mice. Flow cytometry analysis demonstrated that AvFc binds to ID8 cells in a dose-dependent manner at nanomolar concentrations, with negligible binding to isolated murine reproductive cells. AvFc binding to ID8 cells significantly increased following treatment with kifunensine, a class I alpha-mannosidase inhibitor, and this enhanced binding was abolished following high-mannose glycan digestion with endoglycosidase H, confirming high-mannose dependence. AvFc also induced surrogate ADCC activity against ID8 cells by activation of FcgammaRIIIa. AvFc's antitumor efficacy was assessed in the ID8 OVCA model, where mice were intraperitoneally (i.p.) challenged with 2x10 6 ID8 cells and treated with 15 doses of AvFc (25 mg/kg, i.p., every other day), a non-sugar binding AvFc mutant, or vehicle beginning one-week post-challenge. AvFc treatment significantly prolonged median survival from 46 to 70 days compared with the vehicle control (p adj=0.0216, Log-rank [Mantel-Cox] test with Bonferroni's correction). Cytometry by time-of-flight (CyTOF) analysis performed one day after the final dose revealed that AvFc treatment uniquely led to the expansion of total spleen leukocytes, including Tbet+ Th1 cells, and increased CD8 + T cells expressing the degranulation marker CD107a in the peritoneal fluid, suggesting that AvFc's anticancer efficacy was partially mediated by adaptive immunity. Imaging mass cytometry analysis of ID8 tumors is ongoing. Taken together, these findings highlight AvFc's promising potential as an immunotherapeutic agent for OVCA.
利益披露 Disclosure
K. Mayer, None..
N. Verjan-Garcia, None..
N. Matoba, None.