Rodriguez Lorena, Batlle Alcira, Di Venosa Gabriela, MacRobert Alexander J, Battah Sinan, Daniel Hannelore, Casas Adriana
Centro de Investigaciones sobre Porfirinas y Porfirias, CONICET and Hospital de Clínicas José de San Martín, University of Buenos Aires, Córdoba 2351 1er subsuelo, Ciudad de Buenos Aires, CP 1120AAF, Argentina.
Int J Biochem Cell Biol. 2006;38(9):1530-9. doi: 10.1016/j.biocel.2006.03.002. Epub 2006 Mar 18.
Endogenous porphyrin accumulation after administration of 5-aminolevulinic acid is employed in photodynamic therapy of tumours. Due to its low membrane permeability, esterified 5-aminolevulinic acid derivatives less hydrophilic than the parental compound are under investigation. Knowledge of the mechanisms of 5-aminolevulinic acid derivatives uptake into target cells is essential to understand and improve photodynamic therapy and useful in the design of new derivatives with better affinity and with higher selectivity for tumour cells in specific tissues. The aim of this work was to assess the interaction of 5-aminolevulinic acid derivatives with the intestinal PEPT1 and renal transporter PEPT2 expressed in Pichia pastoris yeasts. We found that Undecanoyl, Hexyl, Methyl and 2-(hydroxymethyl)tetrahydropyranyl 5-aminolevulinic acid esters and the dendron 3m-ALA inhibited (14)C-5-aminolevulinic acid uptake by PEPT2. However, only the Undecanoyl ester inhibited 5-aminolevulinic acid uptake by PEPT1. We have also found through a new developed colorimetric method, that Hexyl and 2-(hydroxymethyl)tetrahydropyranyl 5-aminolevulinic acid esters display more affinity than 5-aminolevulinic acid for PEPT2 whereas none of the compounds surpass 5-aminolevulinic acid affinity for PEPT1. In addition, the Undecanoyl ester binds with high affinity to the membranes of PEPT2 and PEPT1-expressing yeasts and to the control yeasts. The main finding of this work was that some derivatives have the potential to improve 5-aminolevulinic acid-based photodynamic therapy by increased efficiency of transport into cells expressing PEPT2 such as kidney, mammary gland, brain or lung whereas in tissues expressing exclusively PEPT1 the parent 5-aminolevulinic acid remains the compound of choice.
5-氨基乙酰丙酸给药后内源性卟啉的积累被用于肿瘤的光动力治疗。由于其膜通透性低，目前正在研究比母体化合物亲水性更低的酯化5-氨基乙酰丙酸衍生物。了解5-氨基乙酰丙酸衍生物进入靶细胞的机制对于理解和改进光动力治疗至关重要，并且有助于设计对特定组织中的肿瘤细胞具有更好亲和力和更高选择性的新衍生物。这项工作的目的是评估5-氨基乙酰丙酸衍生物与在毕赤酵母中表达的肠道肽转运体1（PEPT1）和肾转运体PEPT2的相互作用。我们发现十一烷酰基、己基、甲基和2-(羟甲基)四氢吡喃基5-氨基乙酰丙酸酯以及树枝状分子3m-ALA抑制了PEPT2对(14)C-5-氨基乙酰丙酸的摄取。然而，只有十一烷酰基酯抑制了PEPT1对5-氨基乙酰丙酸的摄取。我们还通过一种新开发的比色法发现，己基和2-(羟甲基)四氢吡喃基5-氨基乙酰丙酸酯对PEPT2的亲和力比5-氨基乙酰丙酸更高，而没有一种化合物对PEPT1的亲和力超过5-氨基乙酰丙酸。此外，十一烷酰基酯与表达PEPT2和PEPT1的酵母膜以及对照酵母膜具有高亲和力结合。这项工作的主要发现是，一些衍生物有可能通过提高转运到表达PEPT2的细胞（如肾脏、乳腺、脑或肺）中的效率来改善基于5-氨基乙酰丙酸的光动力治疗，而在仅表达PEPT1的组织中，母体5-氨基乙酰丙酸仍然是首选化合物。
