Mesquita Mariana Q, Ferreira Ana Rita, Neves Maria da Graça P M S, Ribeiro Daniela, Fardilha Margarida, Faustino Maria A F
Institute of Biomedicine - iBiMED & Department of Medical Sciences, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal; Department of Chemistry & LAQV-REQUIMTE, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal.
Institute of Biomedicine - iBiMED & Department of Medical Sciences, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal.
J Photochem Photobiol B. 2021 Oct;223:112301. doi: 10.1016/j.jphotobiol.2021.112301. Epub 2021 Aug 26.
Prostate cancer (PCa) is the second most frequent cancer diagnosed in men worldwide. Among the common treatment options, photodynamic therapy (PDT) is being considered a promising local therapy to treat this cancer. Although PDT is an established treatment modality approved for several types of cancer, the low solubility, the reduced tumor selectivity, the absorption in the therapeutic window and the poor clearance from the body of the currently approved photosensitizers (PS) hampers its wide clinical application. In this regard, herein we synthesized three fluorinated porphyrinoid derivatives and entrapped them into polyvinylpyrrolidone (PVP) to prevent their aggregation and preserve their desirable photophysical properties under the physiological environment. In vitro studies revealed the negligible dark cytotoxicity of all PVP formulations (PS1@PVP, PS2@PVP and PS3@PVP) at the tested concentrations (5.0 to 20 μM), but also confirmed the significant photodynamic effect of PS2@PVP and PS3@PVP towards the PCa cell line PC-3, upon red light irradiation at an irradiance of 17.6 mW.cm. To provide insight into the underlying mechanisms of cell death under PDT treatment induced by PS2@PVP and PS3@PVP, their intracellular localization in PC-3 cells was firstly investigated by confocal microscopy. Since both PS2@PVP and PS3@PVP nanoparticles were mainly localized in mitochondria, the involvement of this organelle in PDT-induced apoptosis mediated by both formulations was further explored. Western blot analysis revealed that PDT treatment of PC-3 cells with either PS2@PVP or PS3@PVP resulted in the reduction of the expression level of the anti-apoptotic protein Bcl-2. As the photodamage to Bcl-2 after PDT with PS2@PVP and PS3@PVP was accompanied by the further activation of pro-caspase-3, we assumed that upon irradiation the photogenerated reactive oxygen species (ROS) were able to activate a caspase-dependent apoptotic response as a consequence of a post-mitochondrial event. Taken together, these findings demonstrate that among the tested fluorinated porphyrinoids, PS2@PVP and, particularly, PS3@PVP, are significantly more effective in overall PC-3 cell killing than PS1@PVP, thus highlighting their great potential as therapeutic agents for PCa.
前列腺癌（PCa）是全球男性中第二常见的确诊癌症。在常见的治疗选择中，光动力疗法（PDT）被认为是一种有前景的局部治疗该癌症的方法。尽管PDT是一种已被批准用于多种癌症类型的既定治疗方式，但目前已批准的光敏剂（PS）溶解度低、肿瘤选择性降低、在治疗窗口的吸收以及从体内清除效果不佳，阻碍了其广泛的临床应用。在这方面，我们在此合成了三种氟化卟啉类衍生物，并将它们包裹在聚乙烯吡咯烷酮（PVP）中，以防止它们聚集并在生理环境下保持其理想的光物理性质。体外研究表明，在测试浓度（5.0至20μM）下，所有PVP制剂（PS1@PVP、PS2@PVP和PS3@PVP）的暗细胞毒性可忽略不计，但也证实了在17.6 mW.cm的辐照度下红光照射后，PS2@PVP和PS3@PVP对PCa细胞系PC-3具有显著的光动力效应。为了深入了解PS2@PVP和PS3@PVP诱导的PDT治疗下细胞死亡的潜在机制，首先通过共聚焦显微镜研究了它们在PC-3细胞中的细胞内定位。由于PS2@PVP和PS3@PVP纳米颗粒主要定位于线粒体，因此进一步探索了该细胞器在两种制剂介导的PDT诱导的细胞凋亡中的作用。蛋白质印迹分析表明，用PS2@PVP或PS3@PVP对PC-3细胞进行PDT处理导致抗凋亡蛋白Bcl-2的表达水平降低。由于用PS2@PVP和PS3@PVP进行PDT后对Bcl-2的光损伤伴随着前体半胱天冬酶-3的进一步激活，我们推测照射后光生活性氧（ROS）能够激活线粒体后事件导致的半胱天冬酶依赖性凋亡反应。综上所述，这些发现表明，在测试的氟化卟啉类化合物中，PS2@PVP，特别是PS3@PVP，在总体杀伤PC-3细胞方面比PS1@PVP显著更有效，从而突出了它们作为PCa治疗剂的巨大潜力。
