AGR2, a unique tumor-associated antigen, is a promising candidate for antibody targeting.
AGR2, a unique tumor-associated antigen, is a promising candidate for antibody targeting.
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DOI：
10.18632/oncotarget.26945
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发表时间：
2019-07-02
期刊：
影响因子：
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通讯作者：
Crnogorac-Jurcevic, Tatjana
中科院分区：
文献类型：
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作者：
Liu, Alvin Y;Kanan, Adelle D;Crnogorac-Jurcevic, Tatjana
前梯度2(AGR2)是一种蛋白质二硫键异构酶，有两种亚细胞定位：细胞内(IAGR2)和细胞外(EAGR2)。在表达AGR2的健康细胞中，主要的形式是iAGR2，它位于内质网中。相反，癌细胞在细胞表面分泌和表达eAGR2。我们想测试AGR2是否是癌症特异性肿瘤相关抗原。我们利用两个AGR2抗体P3A5和P1G4在体内进行肿瘤定位和抑制肿瘤生长。所制备的单抗可识别人AGR2和小鼠AGR2。用同基因小鼠模型进行的生物分布实验表明，P3A5AGR2抗体在移植瘤中高摄取，而在正常组织中摄取有限。在移植的人患者来源的eAGR2+胰腺癌异种移植瘤中，用抗体和吉西他滨(Gem)评估肿瘤生长抑制。P1G4+Gem组的抑制作用强于Gem组和P3A5+Gem组。我们将这两种抗体转化为人：鼠嵌合形式：构建的P3A5和P1G4嵌合mVLhCkappa和mVHhCGamma(Gamma1，Gamma2，Gamma4)基因插入单个哺乳动物表达载体，并导入人293F细胞。表达的人：小鼠嵌合的IgG1、IgG2和IgG4抗体保留了AGR2结合。通过对不同耐药性的载体进行串联转染，可以提高转基因细胞的免疫球蛋白产量。当这些嵌合抗体与人血孵育时，可以有效地裂解eAGR2+PC3前列腺癌细胞。因此，我们已经生产出人源化的抗AGR2抗体，经过进一步的测试，可能适合于治疗各种eAGR2+实体瘤。
Anterior gradient 2 (AGR2), a protein disulfide isomerase, shows two subcellular localizations: intracellular (iAGR2) and extracellular (eAGR2). In healthy cells that express AGR2, the predominant form is iAGR2, which resides in the endoplasmic reticulum. In contrast, cancer cells secrete and express eAGR2 on the cell surface. We wanted to test if AGR2 is a cancer-specific tumor-associated antigen. We utilized two AGR2 antibodies, P3A5 and P1G4, for in vivo tumor localization and tumor growth inhibition. The monoclonal antibodies recognized both human AGR2 and mouse Agr2. Biodistribution experiments using a syngeneic mouse model showed high uptake of P3A5 AGR2 antibody in xenografted eAgr2+ pancreatic tumors, with limited uptake in normal tissues. In implanted human patient-derived eAGR2+ pancreatic cancer xenografts, tumor growth inhibition was evaluated with antibodies and Gemcitabine (Gem). Inhibition was more potent by P1G4 + Gem combination than Gem alone or P3A5 + Gem. We converted these two antibodies to human:mouse chimeric forms: the constructed P3A5 and P1G4 chimeric mVLhCkappa and mVHhCgamma (gamma1, gamma2, gamma4) genes were inserted in a single mammalian expression plasmid vector, and transfected into human 293F cells. Expressed human:mouse chimeric IgG1, IgG2 and IgG4 antibodies retained AGR2 binding. Increase in IgG yield by transfected cells could be obtained with serial transfection of vectors with different drug resistance. These chimeric antibodies, when incubated with human blood, effectively lysed eAGR2+ PC3 prostate cancer cells. We have, thus, produced humanized anti-AGR2 antibodies that, after further testing, might be suitable for treatment against a variety of eAGR2+ solid tumors.