Photoimmunotherapy (PIT) employing antibody-photosensitizer conjugates is a promising treatment for cancer. However, the fixed antigen specificity severely limits the efficacy and the applicability. Here we describe a universal strategy for PIT of cancer by using a near-infrared (NIR) photosensitizer IRDye700DX-conjugated NeutrAvidin, designated as AvIR, together with various biotinylated antibodies (BioAbs) for cellular targeting. Cytotoxicity of AvIR-mediated PIT was evaluated by fluorescence imaging and cell viability assay. Phototoxic effect on tumorigenicity was assessed by tumorsphere-formation assay and Matrigel invasion assay. Cancer stem cell-like side-population (SP) cells were identified by flow cytometry. CHO cells stably expressing carcinoembryonic antigen or EpCAM were pre-labeled with each BioAb for the corresponding antigen, followed by AvIR administration. NIR light irradiation specifically killed the targeted cells, but not off-targets, demonstrating that the AvIR-mediated PIT does work as expected. CSC-like subpopulation of MCF-7 cells (CD24low/CD44high) and SP of HuH-7 cells (CD133+/EpCAM+) were effectively targeted and photokilled by AvIR-PIT with anti-CD44 BioAb or anti-CD133/anti-EpCAM BioAbs, respectively. As results, the neoplastic features of the cell lines were sufficiently suppressed. Cancer-associated fibroblast (CAF)-targeted AvIR-PIT by using anti-fibroblast activation protein BioAb showed an abolishment of CAF-enhanced clonogenicity of MCF-7 cells. Collectively, our results demonstrate that AvIR-mediated PIT can greatly broaden the applicable range of target specificity, with feasibility of efficacious and integrative control of CSC and its microenvironment.

中文翻译：

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使用光敏剂偶联亲和素和生物素偶联靶向抗体的高度通用癌症光免疫疗法

使用抗体-光敏剂偶联物的光免疫疗法 (PIT) 是一种很有前途的癌症治疗方法。然而，固定的抗原特异性严重限制了疗效和适用性。在这里，我们通过使用近红外 (NIR) 光敏剂 IRDye700DX 缀合的 NeutrAvidin（称为 AvIR）以及用于细胞靶向的各种生物素化抗体 (BioAbs) 来描述癌症 PIT 的通用策略。通过荧光成像和细胞活力测定评估 AvIR 介导的 PIT 的细胞毒性。通过肿瘤球形成试验和基质胶侵袭试验评估对致瘤性的光毒性作用。通过流式细胞术鉴定癌症干细胞样侧群（SP）细胞。用每种 BioAb 对稳定表达癌胚抗原或 EpCAM 的 CHO 细胞进行相应抗原的预标记，其次是 AvIR 管理。NIR 光照射特异性地杀死了目标细胞，但没有杀死目标细胞，这表明 AvIR 介导的 PIT 确实按预期工作。MCF-7 细胞的 CSC 样亚群 (CD24low/CD44high) 和 HuH-7 细胞的 SP (CD133+/EpCAM+) 被具有抗 CD44 BioAb 或抗 CD133/抗 EpCAM BioAbs 的 AvIR-PIT 有效靶向和光杀伤，分别。结果，细胞系的肿瘤特征被充分抑制。通过使用抗成纤维细胞活化蛋白 BioAb 靶向癌症相关成纤维细胞 (CAF) 的 AvIR-PIT 显示消除了 CAF 增强的 MCF-7 细胞的克隆形成。总的来说，我们的结果表明 AvIR 介导的 PIT 可以大大拓宽靶标特异性的适用范围，