Department of Medicine, Graduate School, Dongguk University, Gyeongju 38067, Korea.
Research Institute of Convergence of Biomedical Sciences, Pusan National University Yangsan Hospital, Gyeongnam 50612, Korea.
Int J Mol Sci. 2022 Mar 25;23(7):3594. doi: 10.3390/ijms23073594.
Stimulus-sensitive, nanomedicine-based photosensitizer delivery has an opportunity to target tumor tissues since oxidative stress and the expression of molecular proteins, such as CD44 receptors, are elevated in the tumor microenvironment. The aim of this study is to investigate the CD44 receptor- and reactive oxygen species (ROS)-sensitive delivery of nanophotosensitizers of chlorin e6 (Ce6)-conjugated hyaluronic acid (HA) against HeLa human cervical cancer cells. For the synthesis of nanophotosensitizers, thioketal diamine was conjugated with the carboxyl group in HA and then the amine end group of HA-thioketal amine conjugates was conjugated again with Ce6 (Abbreviated as HAthCe6). The HAthCe6 nanophotosensitizers were of small diameter, with sizes less than 200. Their morphology was round-shaped in the observations using a transmission electron microscope (TEM). The HAthCe6 nanophotosensitizers responded to oxidative stress-induced changes in size distribution when HO was added to the nanophotosensitizer aqueous solution, i.e., their monomodal distribution pattern at 0 mM HO was changed to dual- and/or multi-modal distribution patterns at higher concentrations of HO. Furthermore, the oxidative stress induced by the HO addition contributed to the disintegration of HAthCe6 nanophotosensitizers in morphology, and this phenomenon accelerated the release rate of Ce6 from nanophotosensitizers. In a cell culture study using HeLa cells, nanophotosensitizers increased Ce6 uptake ratio, ROS generation and PDT efficacy compared to free Ce6. Since HA specifically bonds with the CD44 receptor of cancer cells, the pretreatment of free HA against HeLa cells decreased the Ce6 uptake ratio, ROS generation and PDT efficacy of HAthCe6 nanophotosensitizers. These results indicated that intracellular delivery of HAthCe6 nanophotosensitizers can be controlled by the CD44 receptor-mediated pathway. Furthermore, these phenomena induced CD44 receptor-controllable ROS generation and PDT efficacy by HAthCe6 nanophotosensitizers. During in vivo tumor imaging using HeLa cells, nanophotosensitizer administration showed that the fluorescence intensity of tumor tissues was relatively higher than that of other organs. When free HA was pretreated, the fluorescence intensity of tumor tissue was relatively lower than those of other organs, indicating that HAthCe6 nanophotosensitizers have CD44 receptor sensitivity and that they can be delivered by receptor-specific manner. We suggest that HAthCe6 nanophotosensitizers are promising candidates for PDT in cervical cancer.
刺激敏感的基于纳米医学的光敏剂递送有机会靶向肿瘤组织，因为氧化应激和分子蛋白（如 CD44 受体）的表达在肿瘤微环境中升高。本研究的目的是研究氯 e6（Ce6）-接枝透明质酸（HA）的纳米光敏剂的 CD44 受体和活性氧（ROS）敏感性递送，以对抗 HeLa 人宫颈癌细胞。为了合成纳米光敏剂，硫代缩醛二胺与 HA 的羧基偶联，然后再次将 HA-硫代缩醛胺缀合物的胺端基与 Ce6 偶联（缩写为 HAthCe6）。HAthCe6 纳米光敏剂的直径较小，小于 200nm。在透射电子显微镜（TEM）的观察中，它们的形态为圆形。当向纳米光敏剂水溶液中加入 HO 时，HAthCe6 纳米光敏剂会响应氧化应激诱导的尺寸分布变化，即它们在 0mM HO 时的单模态分布模式在更高浓度的 HO 时变为双模态和/或多模态分布模式。此外，HO 加入诱导的氧化应激导致 HAthCe6 纳米光敏剂在形态上的崩解，这种现象加速了 Ce6 从纳米光敏剂中的释放速率。在使用 HeLa 细胞的细胞培养研究中，与游离 Ce6 相比，纳米光敏剂增加了 Ce6 的摄取率、ROS 的产生和 PDT 效果。由于 HA 特异性地与癌细胞的 CD44 受体结合，因此在用游离 HA 预处理 HeLa 细胞后，HAthCe6 纳米光敏剂的 Ce6 摄取率、ROS 的产生和 PDT 效果降低。这些结果表明，HAthCe6 纳米光敏剂的细胞内递呈可以通过 CD44 受体介导的途径来控制。此外，这些现象通过 HAthCe6 纳米光敏剂诱导了 CD44 受体可控的 ROS 生成和 PDT 效果。在使用 HeLa 细胞进行体内肿瘤成像期间，纳米光敏剂给药显示肿瘤组织的荧光强度相对高于其他器官。当用游离 HA 预处理时，肿瘤组织的荧光强度相对低于其他器官，表明 HAthCe6 纳米光敏剂具有 CD44 受体敏感性，可以通过受体特异性方式进行递呈。我们建议 HAthCe6 纳米光敏剂是宫颈癌 PDT 的有前途的候选物。
