Cheng Jianjun, Li Wenting, Tan Guanghui, Wang Zhiqiang, Li Shuying, Jin Yingxue
College of Chemistry & Chemical Engineering, Harbin Normal University, Harbin, 150025, China.
College of Chemistry & Chemical Engineering, Harbin Normal University, Harbin, 150025, China; College of life science and technology, Harbin Normal University, 150025, Harbin, China.
Biomed Pharmacother. 2017 Mar;87:263-273. doi: 10.1016/j.biopha.2016.12.081. Epub 2017 Jan 4.
Photodynamic therapy (PDT) is entering the mainstream of the cancer treatments recently. Pyropheophorbide-a (Pa), as a degradation product of chlorophyll-a, has been shown to be a potent photosensitizer in photodynamic therapy. In this paper, we investigated the in vitro photodynamic therapy of 13-ortho-trifluoromethyl-phenylhydrazone modified pyropheophorbide-a (PHPa) against human HeLa cervical cancer cell line, together with ultraviolet-visible spectra, fluorescence emission spectra, stability in various solvents, and single oxygen quantum yield. The results indicated that PHPa not only showed a greater molar extinction coefficient reached 4.55×10 Lmolcm, the long absorption wavelength (681nm) as we expected that makes it potential in deep tumor treatment, but also showed better stability in near neutral phosphate buffers (pH 7.4) and culture medium, as well as higher single oxygen quantum yield (Ф=40.5%) in DMF solutions. Moreover, cell experiments suggested that PHPa could be uptaken by HeLa cells successfully, and has low dark toxicity without irradiation, but remarkable photo-cytotoxicity (IC, 1.92±0.59μM) that the inhibition rate of HeLa cells could increase up 91.4% at 30μM of PHPa after irradiation. In addition, morphological changes of HeLa cells further demonstrated that PHPa can induce damage and apoptotic cell death. Furthermore, the mechanism of photochemical processes was investigated by using specific quenching agent sodium azide (SA) and D-mannitol (DM), respectively, which showed the formation of singlet oxygen (Type II reaction mechanism) may play a predominant role, Type I and Type II photodynamic reactions could occur simultaneously in this PHPa mediated PDT process.
光动力疗法（PDT）近来正进入癌症治疗的主流领域。焦脱镁叶绿酸-a（Pa）作为叶绿素-a的降解产物，已被证明是光动力疗法中一种有效的光敏剂。在本文中，我们研究了13-邻三氟甲基苯腙修饰的焦脱镁叶绿酸-a（PHPa）对人宫颈癌HeLa细胞系的体外光动力治疗效果，同时研究了其紫外可见光谱、荧光发射光谱、在各种溶剂中的稳定性以及单线态氧量子产率。结果表明，PHPa不仅具有更高的摩尔消光系数，达到4.55×10⁴L·mol⁻¹·cm⁻¹，而且具有如我们所期望的较长吸收波长（681nm），这使其在深部肿瘤治疗中具有潜力；此外，它在近中性磷酸盐缓冲液（pH 7.4）和培养基中表现出更好的稳定性，在N,N-二甲基甲酰胺（DMF）溶液中具有更高的单线态氧量子产率（Ф=40.5%）。此外，细胞实验表明，PHPa能够成功被HeLa细胞摄取，在无光照时具有低暗毒性，但具有显著的光细胞毒性（IC₅₀，1.92±0.59μM），在30μM的PHPa光照后，HeLa细胞的抑制率可提高至91.4%。此外，HeLa细胞的形态变化进一步证明PHPa可诱导细胞损伤和凋亡性细胞死亡。此外，分别使用特异性猝灭剂叠氮化钠（SA）和D-甘露醇（DM）研究了光化学过程的机制，结果表明单线态氧的形成（II型反应机制）可能起主要作用，在该PHPa介导的光动力治疗过程中I型和II型光动力反应可能同时发生。
