Institure of Pharmaceutical Sciences of Western Switzerland, University of Geneva, Rue Michel-Servet 1, 1211 Geneva, Switzerland; School of Pharmaceutical Sciences, University of Geneva, Rue Michel-Servet 1, 1211 Geneva, Switzerland.
Institure of Pharmaceutical Sciences of Western Switzerland, University of Geneva, Rue Michel-Servet 1, 1211 Geneva, Switzerland.
J Photochem Photobiol B. 2022 Aug;233:112484. doi: 10.1016/j.jphotobiol.2022.112484. Epub 2022 May 30.
5-ALA-mediated photodynamic therapy (PDT) has been developed around the heme biosynthesis physiological pathway. It is based on the external supplementation of 5 aminolevulinic acid (5-ALA), increasing the activity of the heme pathway and leading to a significant protoporphyrin IX (PpIX) accumulation. Interestingly, this metbolite accumulation is predominant in cancer cells, induced by a highly active metabolism, therefore limiting off-target side effects and increasing therapy specificity. Nevertheless, the intrinsic mechanism responsible of PpIX accumulation on cells following PDT is still unknown, limiting clinical therapy translation. In order to further understand the mechanisms behind 5-ALA-induced PDT, in this study we aimed to evaluate the proteome changes reported on the physiological heme pathway, in response to an external 5-ALA supplementation. We studied two different scenarios following 5-ALA treatment, 5-ALA accumulation (5-ALA metabolization into the heme pathway blocked with inhibitors) and accumulation of PpIX (normal heme pathway with 5-ALA supplementation). Therefore, we were able to characterize enzymatic changes and to describe bottlenecks in the pathway. Following mass spectrometry analysis, we reported significant differences between 5-ALA and PpIX effects on heme biosynthesis and regulation of degradation. 5-ALA accumulation significantly decreased porphobilinogen deaminase (HMBS) expression, while phorphyrins accumulation (PpIX) upregulated heme synthesis, specifically HMBS and uroporphyrinogen decarboxylase (UROD), and enhanced the enzymatic level of the heme degradation pathway, including Heme oxygenase 1 (HMOX1) and biliverdin reductase A (BLVRA). Interestingly, porphyrins induced a significant downregulation effect on oxygen-dependent coproporphyrinogen-III oxidase (CPOX). In conclusion, in this study we demonstrated that porphyrins play the most relevant role in heme biosynthesis modulation, while 5-ALA alone (PDT substrate) is not responsible of the main changes observed in this pathway during PDT treatment. Understanding heme enzyme modulation would help to design a more rational approach for patient treatment in the clinic. AIM: Effect of 5-ALA and porphyrins on the different Heme biosynthesis and degradation enzymes.
5-ALA 介导的光动力疗法（PDT）是围绕血红素生物合成生理途径开发的。它基于外部补充 5-氨基酮戊酸（5-ALA），增加血红素途径的活性，导致显著的原卟啉 IX（PpIX）积累。有趣的是，这种代谢物的积累主要发生在癌细胞中，这是由高度活跃的代谢引起的，因此限制了非靶向副作用，并提高了治疗的特异性。然而，PDT 后导致细胞中 PpIX 积累的内在机制仍不清楚，限制了临床治疗的转化。为了进一步了解 5-ALA 诱导的 PDT 的机制，在这项研究中，我们旨在评估生理血红素途径中报告的与外部 5-ALA 补充相关的蛋白质组变化。我们研究了 5-ALA 治疗后的两种不同情况，5-ALA 积累（用抑制剂阻断 5-ALA 代谢成血红素途径）和 PpIX 积累（正常血红素途径加 5-ALA 补充）。因此，我们能够描述酶学变化和途径中的瓶颈。通过质谱分析，我们报告了 5-ALA 和 PpIX 对血红素生物合成和降解调节的影响之间的显著差异。5-ALA 积累显著降低了卟胆原脱氨酶（HMBS）的表达，而卟啉的积累（PpIX）上调了血红素的合成，特别是 HMBS 和尿卟啉原脱羧酶（UROD），并增强了血红素降解途径的酶水平，包括血红素加氧酶 1（HMOX1）和胆红素还原酶 A（BLVRA）。有趣的是，卟啉诱导了氧依赖性粪卟啉原 III 氧化酶（CPOX）的显著下调效应。总之，在这项研究中，我们证明了卟啉在血红素生物合成调节中起着最重要的作用，而单独的 5-ALA（PDT 底物）不是 PDT 治疗期间该途径中观察到的主要变化的原因。了解血红素酶的调节将有助于设计更合理的临床患者治疗方法。目的：5-ALA 和卟啉对不同血红素生物合成和降解酶的影响。
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