Iron chelators have recently attracted interest in the field of photodynamic therapy (PDT) owing to their role in enhancement of intracellular protoporphyrin IX (PpIX) generation induced by 5-aminolevulinic acid (ALA) via the biosynthetic heme cycle. Although ALA is widely used in PDT, cellular uptake of ALA is limited by its hydrophilicity. In order to improve ALA delivery and enhance the PpIX production, several dendrimers incorporating both ALA and 3-hydroxy-4-pyridinone (HPO) were synthesized. The ability of the dendrimers to enter cells and be metabolized to the PpIX photosensitizer was studied in several human cancer cell lines. The dendrimers were found to be significantly more efficient than ALA alone in PpIX production. The higher intracellular PpIX levels showed a clear correlation with enhanced cellular phototoxicity following light exposure. Dendritic derivatives are therefore capable of efficiently delivering both ALA and HPO, which act synergistically to amplify in vitro PpIX levels and enhance PDT efficacy.
最近,
铁螯合剂在光动力疗法(PDT)领域引起了人们的兴趣,这是因为
铁螯合剂能通过
生物合成血红素循环,增强
5-氨基乙酰丙酸(A
LA)诱导的细胞内
原卟啉 IX(PpIX)的生成。虽然 A
LA 被广泛应用于光导疗法,但由于其亲
水性,细胞对 A
LA 的吸收受到限制。为了改善 A
LA 的输送并提高 PpIX 的产生,我们合成了几种同时含有 A
LA 和 3-羟基-4-
吡啶酮(HPO)的树枝状聚合物。在几种人类癌
细胞系中研究了树枝状聚合物进入细胞并代谢为 PpIX 光敏剂的能力。研究发现,树枝状聚合物产生 PpIX 的效率明显高于 A
LA 本身。细胞内较高的 PpIX
水平与光照射后细胞光毒性的增强有明显的相关性。因此,树枝状衍
生物能够有效地传递 A
LA 和 HPO,两者协同增效,提高体外 PpIX
水平,增强 PDT 疗效。