Gontijo Sávio M L, Felizali Renata C, Guimarães Pedro P G, Santos Robson A S, Sinisterra Rubén D, Cortés Maria E, Araújo Patrícia V
Restorative Dentistry Department, Faculty of Dentistry, Universidade Federal de Minas Gerais, Av. Antônio Carlos 6627, CEP 31270-901 Belo Horizonte, MG, Brazil.
Chemistry Department, Institute of Exact Sciences, Universidade Federal de Minas Gerais, Av. Antônio Carlos 6627, CEP 31270-901 Belo Horizonte, MG, Brazil.
Photodiagnosis Photodyn Ther. 2017 Jun;18:252-256. doi: 10.1016/j.pdpdt.2017.03.010. Epub 2017 Mar 23.
Photodynamic therapy (PDT) is an antitumour treatment that employs the combination of a photosensitive compound, oxygen and visible light. To improve the antitumour activity of PDT, the present study used the strategy of combining PDT with erlotinib (ERL), a drug frequently used in the treatment of epidermoid carcinoma.
An MTT cell viability assay was used to evaluate the cytotoxicity of PDT combined with ERL on A431 epidermoid carcinoma cells in vitro. This study evaluated the cytotoxicity of the following treatments: red laser irradiation (660nm) at different power densities (1.25-180J/cm), the photosensitizer methylene blue (MB) at concentrations of 0.39-100μM, PDT (12.5μM MB and laser power densities from 1.25 to 180J/cm), and PDT (12.5μM MB and a laser density of 120J/cm) plus ERL (1μM).
The laser power densities that were tested showed no cytotoxicity in A431 cells. MB showed a dose-dependent cytotoxicity. In PDT, an increase in the dose of light resulted in an increase in the cytotoxicity of MB. In addition, there was a sub-additive effect between PDT and ERL compared to the effect of each therapy alone.
The sub-additive effect between PDT and ERL suggests that their combination may be an important strategy in the treatment of epidermoid carcinoma.
光动力疗法（PDT）是一种采用光敏化合物、氧气和可见光相结合的抗肿瘤治疗方法。为提高PDT的抗肿瘤活性，本研究采用了将PDT与厄洛替尼（ERL）联合使用的策略，厄洛替尼是一种常用于治疗表皮样癌的药物。
采用MTT细胞活力测定法在体外评估PDT联合ERL对A431表皮样癌细胞的细胞毒性。本研究评估了以下治疗方法的细胞毒性：不同功率密度（1.25 - 180J/cm）的红色激光照射（660nm）、浓度为0.39 - 100μM的光敏剂亚甲蓝（MB）、PDT（12.5μM MB和1.25至180J/cm的激光功率密度）以及PDT（12.5μM MB和120J/cm的激光密度）加ERL（1μM）。
所测试的激光功率密度在A431细胞中未显示出细胞毒性。MB表现出剂量依赖性细胞毒性。在PDT中，光照剂量的增加导致MB细胞毒性增加。此外，与单独使用每种疗法的效果相比，PDT和ERL之间存在亚相加效应。
PDT和ERL之间的亚相加效应表明它们的联合可能是治疗表皮样癌的一种重要策略。
