Background: Lung cancer is the leading cause of cancer-associated mortality in the world. Traditional cancer therapies prolong the life expectancy of patients but often suffer from adverse reactions. Photodynamic Therapy (PDT) has been recommended as a treatment option for lung cancer in several countries, due to its non-invasive procedures, high selectivity and weak side effects.

Objective: We have designed and synthesized a biotin receptor-targeted silicon phthalocyanine (IV) (compound 1) which showed a good therapeutic effect on biotin receptor-positive tumors. Since the overexpression of Biotin Receptor (BR) is also present in human lung cancer cells (A549), we explored the therapeutic properties of compound 1 on A549 xenograft tumor models.

Methods: The selectivity of compound 1 toward A549 cells was studied with a fluorescence microscope and IVIS Spectrum Imaging System. The cytotoxicity was measured using the MTT assay. In vivo anti-tumor activity was investigated on the nude mice bearing A549 xenografts.

Results: In vitro assays proved that compound 1 could selectively accumulate in A549 cells via the BR-mediated internalization. In vivo imaging and distribution experiments showed that compound 1 could selectively accumulate in tumor tissues of tumor-bearing mice. After 16 days of the treatment, the volumes of tumor in the PDT group were obviously smaller than that in other groups.

Conclusion: This study demonstrates that compound 1 is a promising photosensitizer and has broad application prospects in clinical PDT of lung cancers.

背景：肺癌是世界上与癌症相关的死亡率的主要原因。传统的癌症疗法延长了患者的预期寿命，但常常遭受不良反应。由于光动力疗法（PDT）的非侵入性程序，高选择性和较弱的副作用，因此在一些国家被推荐作为肺癌的治疗选择。

目的：我们设计并合成了靶向生物素受体的酞菁硅（IV）（化合物1），对生物素受体阳性肿瘤具有良好的治疗效果。由于人肺癌细胞（A549）中也存在生物素受体（BR）的过表达，因此我们探讨了化合物1在A549异种移植肿瘤模型中的治疗特性。

方法：用荧光显微镜和IVIS光谱成像系统研究化合物1对A549细胞的选择性。使用MTT测定法测量细胞毒性。在带有A549异种移植物的裸鼠上研究了体内抗肿瘤活性。

结果：体外测定证明化合物1可通过BR介导的内在化选择性地积聚在A549细胞中。体内成像和分布实验表明，化合物1可以选择性地蓄积在荷瘤小鼠的肿瘤组织中。治疗16天后，PDT组的肿瘤体积明显小于其他组。

结论：这项研究表明化合物1是一种有前途的光敏剂，在肺癌的临床PDT中具有广阔的应用前景。