TY - JOUR
T1 - Nuclear factor-κB activation by the photochemotherapeutic agent verteporfin
AU - Granville, D. J.
AU - Carthy, C. M.
AU - Jiang, H.
AU - Levy, J. G.
AU - McManus, B. M.
AU - Matroule, J. Y.
AU - Piette, J.
AU - Hunt, David W C
PY - 2000/1/1
Y1 - 2000/1/1
N2 - The nuclear factor-kappa B (NF-κB) gene transactivator serves in the formation of immune, inflammatory, and stress responses. In quiescent cells, NF-κB principally resides within the cytoplasm in association with inhibitory K (IκB) proteins. The status of IκB and NF-κB proteins was evaluated for promyelocytic leukemia HL-60 cells treated at different intensities of photodynamic therapy (PDT). The action of the potent photosensitizer, benzoporphyrin derivative mono-acid ring A (verteporfin), and visible light irradiation were assessed. At a verteporfin concentration that produced the death of a high proportion of cells after light irradiation, evidence of caspase-3 and caspase-9 processing and of poly(ADP- ribose) polymerase cleavage was present within whole cell lysates. The general caspase inhibitor Z-Val-Ala-Asp-fluoromethylketone (ZVAD.fmk) effectively blocked these apoptosis-related changes. Recent studies indicate that IκB proteins may be caspase substrates during apoptosis. However, the level of IκBβ was unchanged for HL-60 cells undergoing PDT-induced apoptosis. IκBα levels decreased during PDT-induced apoptosis, though ZVAD.fmk did not affect this change. At a less intensive level of photosensitization, cellular IκBα levels were transiently depressed after PDT. At these times, p50 and RelA NF-κB species were increased within nuclear extracts, as revealed by electrophoretic mobility supershift assays. HL-60 cells transiently transfected with a κB-luciferase reporter construct exhibited elevated luciferase activity after PDT or treatment with tumor necrosis factor-α, a well-characterized NF-κB activator. Productive NF-κB activation and associated gene transcription may influence the phenotype and behavior of cells exposed to less intensive PDT regimens. However, IκBα is not subject to caspase-mediated degradation as a component of PDT-induced apoptosis.
AB - The nuclear factor-kappa B (NF-κB) gene transactivator serves in the formation of immune, inflammatory, and stress responses. In quiescent cells, NF-κB principally resides within the cytoplasm in association with inhibitory K (IκB) proteins. The status of IκB and NF-κB proteins was evaluated for promyelocytic leukemia HL-60 cells treated at different intensities of photodynamic therapy (PDT). The action of the potent photosensitizer, benzoporphyrin derivative mono-acid ring A (verteporfin), and visible light irradiation were assessed. At a verteporfin concentration that produced the death of a high proportion of cells after light irradiation, evidence of caspase-3 and caspase-9 processing and of poly(ADP- ribose) polymerase cleavage was present within whole cell lysates. The general caspase inhibitor Z-Val-Ala-Asp-fluoromethylketone (ZVAD.fmk) effectively blocked these apoptosis-related changes. Recent studies indicate that IκB proteins may be caspase substrates during apoptosis. However, the level of IκBβ was unchanged for HL-60 cells undergoing PDT-induced apoptosis. IκBα levels decreased during PDT-induced apoptosis, though ZVAD.fmk did not affect this change. At a less intensive level of photosensitization, cellular IκBα levels were transiently depressed after PDT. At these times, p50 and RelA NF-κB species were increased within nuclear extracts, as revealed by electrophoretic mobility supershift assays. HL-60 cells transiently transfected with a κB-luciferase reporter construct exhibited elevated luciferase activity after PDT or treatment with tumor necrosis factor-α, a well-characterized NF-κB activator. Productive NF-κB activation and associated gene transcription may influence the phenotype and behavior of cells exposed to less intensive PDT regimens. However, IκBα is not subject to caspase-mediated degradation as a component of PDT-induced apoptosis.
UR - http://www.scopus.com/inward/record.url?scp=0033628631&partnerID=8YFLogxK
M3 - Article
C2 - 10607710
AN - SCOPUS:0033628631
SN - 0006-4971
VL - 95
SP - 256
EP - 262
JO - Blood
JF - Blood
IS - 1
ER -