Cultured glioblastoma D54Mg cells were photosensitized with 5-aminolevulinic acid so that cell survival was 95-100 % . At following 0.5-5.5 h protein expression and phosphorylation was assayed using proteomic antibody microarrays.
Within the first post-treatment hour we observed phosphorylation of protein kinase Raf, adhesion-related kinases FAK and Pyk2, and microtubule-associated protein tau. Protein kinase C¦Ã and microtubule-associated protein MAP-1B were overexpressed. Dystrophin, calponin, and vinculin, components of the actin cytoskeleton scaffold, microtubule-associated proteins MAP2 and CNP, cytokeratins 4 and 7 were down-regulated that indicated changes in adhesion and cell shape. Down-regulation of cyclins A, D1 and D3, c-Myc, checkpoint proteins chk1/2 and up-regulation of Smad4 could arrest the cell cycle. Overexpression of Bcl-xL and down-regulation of caspase 9 demonstrated anti-apoptotic response. At 2 h post-treatment protein expression changed lesser but at 5.5 h levels of PKC¦Ã and ¦Â-synuclein and phosphorylation of Raf, FAK, Pyk2, and tau increased again.
Sub-lethal PDT induces complex response of glioblastoma cells including changes in activity and expression of proteins involved in adhesion-mediated signaling, signal transduction, cytoskeleton remodeling, cell cycle regulation and anti-apoptotic processes.
Multiple reactions of various cellular subsystems including adhesion, cytoskeleton, signal transduction, cell cycle, and apoptosis are integrated into the general cell response to a sublethal impact.