Protein changes in HL60 leukemia cells associated with 5-aminolevulinic acid-based photodynamic therapy. Early effects on endoplasmic reticulum chaperones

Using two-dimensional electrophoresis we investigated the effect of 5-amino levulinic acid (ALA)-based photodynamic therapy (PDT; induction with 1 mM A LA for 4 h followed by blue light dose of 18 J/cm(2)) on the protein expres sion in HL60 leukemia cells. AEA-PDT resulted in extensive qualitative and quantitative changes in the protein pattern of HL60 fell lysates. Of more t han 1350 protein spots recognized on the protein maps of ALA-induced cells, seven proteins were enhanced and 17 suppressed following irradiation. Thre e of these, calreticulin presursor, p58 microsomal protein (ERp57) and prot ein disulfide isomerase (p55) have been identified by matrix-assisted laser desorption and ionization-mass spectrometry and the pI/molecular weight pa rameters of the affected proteins were estimated by computer analysis. The findings suggest participation of endoplasmic reticulum Ca2+-binding chaper ones and/or Ca2+ signaling in ALA-PDT mediated cytotoxicity.