Simelane Nokuphila Winifred Nompumelelo, Abrahamse Heidi
Laser Research Centre, Faculty of Health Sciences, University of Johannesburg, Johannesburg, South Africa.
Front Mol Biosci. 2024 Jan 8;10:1340212. doi: 10.3389/fmolb.2023.1340212. eCollection 2023.
In conventional photodynamic therapy (PDT), effective delivery of photosensitizers (PS) to cancer cells can be challenging, prompting the exploration of active targeting as a promising strategy to enhance PS delivery. Typically, two-dimensional (2-D) monolayer cell culture models are used for investigating targeted photodynamic therapy. However, despite their ease of use, these cell culture models come with certain limitations due to their structural simplicity when compared to three-dimensional (3-D) cell culture models such as multicellular tumour spheroids (MCTSs). In this study, we prepared gold nanoparticles (AuNPs) that were functionalized with antibodies and loaded with tetra sulphonated zinc phthalocyanine (ZnPcS). Characterization techniques including transmission electron microscopy (TEM) was used to determine the size and morphology of the prepared nanoconjugates. We also conducted a comparative investigation to assess the photodynamic effects of ZnPcS alone and/or conjugated onto the bioactively functionalized nanodelivery system in colorectal Caco-2 cells cultured in both 2-D monolayers and 3-D MCTSs. TEM micrographs revealed small, well distributed, and spherical shaped nanoparticles. Our results demonstrated that biofunctionalized nanoparticle mediated PDT significantly inhibited cell proliferation and induced apoptosis in Caco-2 cancer monolayers and, to a lesser extent, in Caco-2 MCTSs. Live/dead assays further elucidated the impact of actively targeted nanoparticle-photosensitizer nanoconstruct, revealing enhanced cytotoxicity in 2-D cultures, with a notable increase in dead cells post-PDT. In 3-D spheroids, however, while the presence of targeted nanoparticle-photosensitizer system facilitated improved therapeutic outcomes, the live/dead results showed a higher number of viable cells after PDT treatment compared to their 2-D monolayer counterparts suggesting that MCTSs showed more resistance to PS drug as compared to 2-D monolayers. These findings suggest a high therapeutic potential of the multifunctional nanoparticle as a targeted photosensitizer delivery system in PDT of colorectal cancer. Furthermore, the choice of cell culture model influenced the response of cancer cells to PDT treatment, highlighting the feasibility of using MCTSs for targeted PS delivery to colorectal cancer cells.
在传统光动力疗法（PDT）中，将光敏剂（PS）有效递送至癌细胞可能具有挑战性，这促使人们探索主动靶向作为增强PS递送的一种有前景的策略。通常，二维（2-D）单层细胞培养模型用于研究靶向光动力疗法。然而，尽管其使用方便，但与三维（3-D）细胞培养模型（如多细胞肿瘤球体（MCTS））相比，这些细胞培养模型由于结构简单而存在一定局限性。在本研究中，我们制备了用抗体功能化并负载四磺酸锌酞菁（ZnPcS）的金纳米颗粒（AuNP）。使用包括透射电子显微镜（TEM）在内的表征技术来确定所制备的纳米缀合物的尺寸和形态。我们还进行了一项比较研究，以评估单独的ZnPcS和/或缀合到生物活性功能化纳米递送系统上在二维单层和三维MCTS中培养的结肠直肠癌Caco-2细胞中的光动力效应。TEM显微照片显示纳米颗粒小、分布均匀且呈球形。我们的结果表明，生物功能化纳米颗粒介导的PDT在Caco-2癌单层中显著抑制细胞增殖并诱导凋亡，在Caco-2 MCTS中的抑制程度较小。活/死分析进一步阐明了主动靶向的纳米颗粒 - 光敏剂纳米构建体的影响，揭示了二维培养物中增强的细胞毒性，光动力疗法后死细胞显著增加。然而，在三维球体中，虽然靶向纳米颗粒 - 光敏剂系统的存在促进了治疗效果的改善，但活/死结果显示，与二维单层对应物相比，光动力疗法治疗后存活细胞数量更多，这表明MCTS比二维单层对PS药物表现出更强的抗性。这些发现表明多功能纳米颗粒作为结直肠癌光动力疗法中靶向光敏剂递送系统具有很高的治疗潜力。此外，细胞培养模型的选择影响癌细胞对光动力疗法治疗的反应，突出了使用MCTS将靶向PS递送至结肠直肠癌细胞的可行性。
