Bogazici University, Institute of Biomedical Engineering, Uskudar, Istanbul, 34684, Turkey.
Erzincan University, Engineering Faculty, Biomedical Engineering, Erzincan, 24100, Turkey.
Photodiagnosis Photodyn Ther. 2018 Mar;21:334-343. doi: 10.1016/j.pdpdt.2018.01.008. Epub 2018 Jan 12.
The Food and Drug Administration-approved Indocyanine Green can be used as a photosensitizer to kill cancer cells selectively. Although indocyanine green is advantageous as a photosensitizer in terms of strong absorption in the near-infrared region, indocyanine green-based cancer treatment is still not approved as a clinical method. Some reasons for this are aggregation at high concentrations, rapid clearance of the photosensitizer from the body, low singlet oxygen quantum yield, and the uncertainty concerning its action mechanism. This in vitro study focuses on two of these points: "what is the cell inhibition mechanism of indocyanine green-based therapy?" and "how the dose-dependent aggregation problem of indocyanine green alters its cell inhibition efficiency?" The following experiments were conducted to provide insight into these points. Nontoxic doses of indocyanine green and near-infrared laser were determined. The aggregation behavior of indocyanine green was verified through experiments. The singlet oxygen quantum yield of indocyanine green at different concentrations were calculated. Various indocyanine green and energy densities of near-infrared light were applied to prostate cancer, neuroblastoma, and colon cancer cells. An MTT assay was performed at the end of the first, second, and third days following the treatments to determine the cell viability. Temperature changes in the medium during laser exposure were recorded. ROS generation following the treatment was verified by using a Total Reactive Oxygen Species detection kit. An apoptosis detection test was performed to establish the cell death mechanism and, finally, the cellular uptakes of the three different cells were measured. According to the results, indocyanine green-based therapy causes cell viability decrease for three cancer cell lines by means of excessive reactive oxygen species production. Different cells have different sensitivities to the therapy possibly because of the differentiation level and structural differences. The singlet oxygen generation of indocyanine green decreases at high concentrations because of aggregation. Nevertheless, better cancer cell killing effect was observed at higher photosensitizer concentrations. This result reveals that the cellular uptake of indocyanine green was determinant for better cancer cell inhibition.
美国食品和药物管理局批准的吲哚菁绿可用作光敏剂，有选择性地杀死癌细胞。虽然吲哚菁绿作为光敏剂在近红外区域具有很强的吸收优势，但基于吲哚菁绿的癌症治疗仍未被批准为临床方法。造成这种情况的一些原因是在高浓度下聚集、光敏剂从体内迅速清除、单线态氧量子产率低以及对其作用机制的不确定性。这项体外研究集中在其中两个方面：“基于吲哚菁绿的治疗的细胞抑制机制是什么？”以及“吲哚菁绿的剂量依赖性聚集问题如何改变其细胞抑制效率？”进行了以下实验以提供对这些问题的深入了解。确定了非毒性剂量的吲哚菁绿和近红外激光。通过实验验证了吲哚菁绿的聚集行为。计算了不同浓度下吲哚菁绿的单线态氧量子产率。将不同浓度的吲哚菁绿和近红外光的能量密度应用于前列腺癌、神经母细胞瘤和结肠癌细胞。处理后第一天、第二天和第三天结束时进行 MTT 测定以确定细胞活力。记录激光照射过程中介质温度的变化。使用总活性氧检测试剂盒验证处理后 ROS 的产生。进行凋亡检测试验以确定细胞死亡机制，最后测量三种不同细胞的细胞摄取量。结果表明，基于吲哚菁绿的治疗通过产生过多的活性氧导致三种癌细胞系的细胞活力下降。不同的细胞对治疗的敏感性可能因分化水平和结构差异而异。由于聚集，吲哚菁绿的单线态氧生成在高浓度下降低。然而，在较高的光敏剂浓度下观察到更好的癌细胞杀伤效果。该结果表明，吲哚菁绿的细胞摄取对于更好的癌细胞抑制是决定性的。
