Laboratory of Cancer Biology, Institute of Biomedicine and Translational Medicine, University of Tartu, 50411, Tartu, Estonia.
Curr Cancer Drug Targets. 2021;21(1):70-79. doi: 10.2174/1568009620666201001112749.
Conjugation to clinical-grade tumor penetrating iRGD peptide is a widely used strategy to improve tumor homing, extravasation, and penetration of cancer drugs and tumor imaging agents. The C domain of the extracellular matrix molecule Tenascin-C (TNC-C) is upregulated in solid tumors and represents an attractive target for clinical-grade single-chain antibody- based vehicles for tumor delivery drugs and imaging agents.
To study the effect of C-terminal genetic fusion of the iRGD peptide to recombinant anti- TNC-C single-chain antibody clone G11 on systemic tumor homing and extravasation.
Enzyme-linked immunosorbent assay was used to study the interaction of parental and iRGD-fused anti-TNC-C single-chain antibodies with C domain of tenascin-C and αVβ3 integrins. For systemic homing studies, fluorescein-labeled ScFV G11-iRGD and ScFV G11 antibodies were administered in U87-MG glioblastoma xenograft mice, and their biodistribution was studied by confocal imaging of tissue sections stained with markers of blood vessels and Tenascin C immunoreactivity.
In a cell-free system, iRGD fusion to ScFV G11 conferred the antibody has a robust ability to bind αVβ3 integrins. The fluorescein labeling of ScFV G11-iRGD did not affect its target binding activity. In U87-MG mice, iRGD fusion to ScFV G11 antibodies improved their homing to tumor blood vessels, extravasation, and penetration of tumor parenchyma.
The genetic fusion of iRGD tumor penetrating peptide to non-internalizing affinity targeting ligands may improve their tumor tropism and parenchymal penetration for more efficient delivery of imaging and therapeutic agents into solid tumor lesions.
将临床级肿瘤穿透 iRGD 肽缀合到药物上是提高肿瘤归巢、外渗和穿透的常用策略癌症药物和肿瘤成像剂。细胞外基质分子 tenascin-C（TNC-C）的 C 结构域在实体瘤中上调，代表了临床级单链抗体的一个有吸引力的靶点用于肿瘤传递药物和成像剂的载体。
研究 iRGD 肽的 C 末端基因融合到重组抗 TNC-C 单链抗体克隆 G11 对系统肿瘤归巢和外渗的影响。
酶联免疫吸附试验用于研究亲本和 iRGD 融合的抗 TNC-C 单链抗体与 tenascin-C 的 C 结构域和 αVβ3 整合素的相互作用。对于系统归巢研究，在 U87-MG 胶质母细胞瘤异种移植小鼠中给予荧光素标记的 ScFV G11-iRGD 和 ScFV G11 抗体，并通过用血管标志物和 Tenascin C 免疫反应性染色的组织切片进行共聚焦成像来研究其生物分布。
在无细胞系统中，iRGD 融合到 ScFV G11 赋予了抗体与 αVβ3 整合素结合的强大能力。ScFV G11-iRGD 的荧光标记不影响其靶标结合活性。在 U87-MG 小鼠中，iRGD 融合到 ScFV G11 抗体可改善其归巢到肿瘤血管、外渗和穿透肿瘤实质。
将 iRGD 肿瘤穿透肽与非内化亲和力靶向配体进行基因融合可能会提高它们对肿瘤的趋向性和实质穿透性，从而更有效地将成像和治疗剂递送至实体瘤病变。
