Photosensitization, uptake, and retention of phenoxazine Nile blue derivatives in human bladder carcinoma cells.
Photosensitization, uptake, and retention of phenoxazine Nile blue derivatives in human bladder carcinoma cells.
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发表时间：
1991-02
期刊：
影响因子：
11.2
通讯作者：
Chi-Wei Lin;J. Shulok;Yau-Kai Wong;Carl F. Schanbacher;L. Cincotta;James W. Foley
中科院分区：
文献类型：
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作者：
Chi-Wei Lin;J. Shulok;Yau-Kai Wong;Carl F. Schanbacher;L. Cincotta;James W. Foley
本研究的总体目标是开发有效的新型光敏剂用于肿瘤选择性光动力治疗。众所周知，吩恶嗪染料（包括几种尼罗蓝类似物）可以选择性地定位于动物肿瘤中。结构修饰产生了几个系列的类似物，具有更高的1 O2产量和不同的光化学和物理化学性质。本研究检查了这些衍生物在培养的人膀胱癌细胞（MGH-U1）中的光敏效力、细胞摄取和保留。选择含有卤素和/或硫取代基的尼罗蓝衍生物以表现出不同的1 O2产率、PKa值和疏水性。这些衍生物在体外介导光杀伤肿瘤细胞的有效性与这些化合物的1 O2产量相对应，表明结构修饰导致1 O2产量增加，从而增强了体外介导光细胞毒性的效力。使用具有最高1 O2量子产率（0.35和0.821）的衍生物（sat-NBS和sat-NBS-61），在5 × 10（-8）M的敏化剂浓度下实现了超过90%的细胞杀伤，比目前临床上唯一可用的敏化剂血卟啉衍生物有效约3个数量级。这一结果表明，一些恶嗪衍生物可能是有效的光敏剂。1 O2产率和光敏效力之间的对应关系，以及结果表明，在D2 O的存在下，增强的光细胞毒性和减少的光细胞毒性在缺氧条件下，强烈表明，1 O2的产生是一个主要的机制介导的光细胞毒性效应。尼罗蓝衍生物的细胞在培养中的摄取表现出一种模式的快速初始摄取，然后逐渐增加细胞染料含量。的摄取不直接相关的个别pKa值或衍生物的疏水性，表明结构的修改，增加1 O2产量没有显着改变尼罗蓝衍生物的摄取和保留。高浓度的摄取和缓慢流出的染料加载的细胞与这些染料的细胞积累的活性机制是一致的。另一方面，保留的化合物是直接成比例的染料浓度在介质中超过1000倍的浓度范围内，和摄取可以进行在温度低于2摄氏度，这些观察排除内吞作用或载体介导的机制的摄取。摄取也不受培养基中存在血清的影响。基于这些结果，我们假设尼罗蓝衍生物可能以去质子化形式跨细胞膜运输，并且在进入细胞后，要么分配到细胞膜的亲脂性区域和/或被隔离在某些细胞内细胞器中。
The overall goal of our research is to develop effective new photosensitizers for tumor-selective photodynamic therapy. Phenoxazine dyes, including several Nile blue analogues, are known to localize selectively in animal tumors. Structural modifications yielded several series of analogues with substantially higher 1O2 yields and different photochemical and physicochemical properties. This study examined the photosensitization potency, cellular uptake, and retention of these derivatives in human bladder carcinoma cells (MGH-U1) in culture. Nile blue derivatives containing halogens and/or sulfur substitutes were selected to exhibit different 1O2 yields, pKa values, and hydrophobicities. The effectiveness of these derivatives in mediating photokilling of tumor cells in vitro corresponded well with the 1O2 yields of these compounds, indicating that structural modifications which resulted in increased 1O2 yields enhanced potency in mediating photocytotoxicity in vitro. Using derivatives (sat-NBS and sat-NBS-61) with the highest 1O2 quantum yield (0.35 and 0.821), over 90% cell kill was achieved at a sensitizer concentration of 5 x 10(-8) M, about 3 orders of magnitude more effective than hematoporphyrin derivative, the only sensitizer currently available clinically. This result suggests that some of the oxazine derivatives could potentially be effective photosensitizers. The correspondence between 1O2 yield and photosensitizing potency, together with results showing enhanced photocytotoxicity in the presence of D2O and reduced photocytotoxicity under hypoxic conditions, strongly suggests that the generation of 1O2 is a major mechanism mediating the photocytotoxic effect. The uptake of Nile blue derivatives by cells in culture exhibited a pattern of rapid initial uptake followed by a gradual increase in cellular dye contents. The uptake does not correlate directly with the individual pKa values or hydrophobicities of the derivatives, indicating that the structural modifications that increased 1O2 yields did not significantly alter the uptake and retention of Nile blue derivatives. The highly concentrative uptake by and slow efflux from dye-loaded cells were consistent with an active mechanism for the cellular accumulation of these dyes. On the other hand, the retention of the compounds was directly proportional to dye concentration in the medium over a 1000-fold range of concentrations, and the uptake could proceed at temperatures below 2 degrees C; these observations excluded endocytosis or a carrier-mediated mechanism for the uptake. The uptake was also unaffected by the presence of serum in the medium. Based on these results, we hypothesize that Nile blue derivatives transport across the cell membrane possibly as deprotonated forms and, upon entering the cell, either partition into lipophilic areas of the cell membranes and/or become sequestered in certain intracellular organelles.