Olarewaju Olaniyi, Held Franziska, Curtis Pamela, Kenny Cynthia Hess, Maier Udo, Panavas Tadas, du Plessis Francois
AAV Gene Therapy Research Group, Research Beyond Borders (RBB), Boehringer Ingelheim Pharma GmbH & Co. KG, 88400 Biberach an der Riß, Germany.
Biotherapeutics Discovery, Boehringer Ingelheim Pharmaceuticals, Inc., Ridgefield, CT 06877, USA.
Mol Ther Methods Clin Dev. 2024 Nov 12;32(4):101378. doi: 10.1016/j.omtm.2024.101378. eCollection 2024 Dec 12.
Due to the refractiveness of tumor tissues to adeno-associated virus (AAV) transduction, AAV vectors are poorly explored for cancer therapy delivery. Here, we aimed to engineer AAVs to target tumors by enabling the specific engagement of fibroblast activation protein (FAP). FAP is a cell surface receptor distinctly upregulated in the reactive tumor stroma, but rarely expressed in healthy tissues. Thus, targeting FAP presents an opportunity to selectively transduce tumor tissues. To achieve this, we modified the capsid surface of AAV2 with an αFAP nanobody to retarget the capsid to engage FAP receptor. Following transduction, we observed a 23- to 80-fold increase in the selective transduction of FAP tumor cells , and greater than 5-fold transduction of FAP tumor tissues Subsequent optimization of the VP1-nanobody expression cassette further enhanced the transduction efficiency of the modified capsids. Due to the limited αFAP nanobodies repertoires, we broadened the versatility of this high-fidelity platform by screening a naive VHH yeast display library, leading to the identification of several novel αFAP nanobody candidates (K = 0.1 to >100 nM). Hence, our study offers new opportunity for the application of AAV vectors for highly selective delivery of therapeutics to the tumor stroma.
由于肿瘤组织对腺相关病毒（AAV）转导具有难治性，AAV载体在癌症治疗递送方面的研究较少。在此，我们旨在通过使成纤维细胞活化蛋白（FAP）特异性结合来改造AAV，使其靶向肿瘤。FAP是一种细胞表面受体，在反应性肿瘤基质中明显上调，但在健康组织中很少表达。因此，靶向FAP为选择性转导肿瘤组织提供了机会。为实现这一目标，我们用αFAP纳米抗体修饰了AAV2的衣壳表面，使衣壳重新靶向以结合FAP受体。转导后，我们观察到FAP肿瘤细胞的选择性转导增加了23至80倍，FAP肿瘤组织的转导增加了5倍以上。随后对VP1-纳米抗体表达盒的优化进一步提高了修饰衣壳的转导效率。由于αFAP纳米抗体的库有限，我们通过筛选天然VHH酵母展示文库拓宽了这个高保真平台的通用性，从而鉴定出了几种新型αFAP纳米抗体候选物（K = 0.1至>100 nM）。因此，我们的研究为AAV载体用于向肿瘤基质高度选择性递送治疗药物提供了新机会。
