Protein Changes in HL60 Leukemia Cells Associated with 5-Aminolevulinic Acid-based Photodynamic Therapy. Early Effects on Endoplasmic Reticulum Chaperones ¶

Abstract
Using two‐dimensional electrophoresis we investigated the effect of 5‐aminolevulinic acid (ALA)–based photodynamic therapy (PDT; induction with 1 mM ALA for 4 h followed by blue light dose of 18 J/cm2) on the protein expression in HL60 leukemia cells. ALA‐PDT resulted in extensive qualitative and quantitative changes in the protein pattern of HL60 cell lysates. Of more than 1350 protein spots recognized on the protein maps of ALA‐induced cells, seven proteins were enhanced and 17 suppressed following irradiation. Three of these, calreticulin presursor, p58 microsomal protein (ERp57) and protein disulfide isomerase (p55) have been identified by matrix‐assisted laser desorption and ionization‐mass spectrometry and the pI/molecular weight parameters of the affected proteins were estimated by computer analysis. The findings suggest participation of endoplasmic reticulum Ca2+‐binding chaperones and/or Ca2+ signaling in ALA‐PDT mediated cytotoxicity.