Photodynamic therapy with 5-aminolevulinic acid induces apoptosis and caspase activation in malignant T cells.
BACKGROUND
Preliminary studies have suggested that photodynamic therapy (PDT) with 5-aminolevulinic acid (ALA) can improve psoriasis and mycosis fungoides, two diseases where normal or malignant T cells play a central role.


OBJECTIVE
To determine if ALA-PDT induces apoptosis and caspase activation in Jurkat cells, a malignant T-cell line.


METHODS
Jurkat cells were incubated with ALA in the presence of [14C]-thymidine followed by red light exposure. DNA fragmentation was measured 24 hours later with a DNA elution assay. The influence on DNA fragmentation of ALA concentration, time between ALA addition and light exposure, as well as light fluence were studied. The occurrence of oligonucleosome-sized DNA fragmentation was also studied with DNA electrophoresis. Caspase-3-like activity was monitored by measuring Ac-DEVD-AMC hydrolysis.


RESULTS
DNA fragmentation as high as 88% was observed 24 hours after ALA-PDT. The percentage of DNA fragmentation increased with increasing doses of ALA, red light fluence, as well as longer incubation time with ALA. DNA fragmentation was observed as early as 3 hours after ALA-PDT. The presence of apoptosis after ALA-PDT was confirmed by DNA electrophoresis. An increase in caspase-3-like activities was detected following ALA-PDT.


CONCLUSIONS
ALA-PDT induces apoptosis and caspase-3-like activation in Jurkat cells.
Division of Dermatology, University of Montreal Hospital Centre, Notre-Dame Hospital, Quebec, Canada.
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F
Gad
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Viau
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M
Boushira
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R
Bertrand
R
R
Bissonnette
D000622:Aminolevulinic Acid / Q000627:therapeutic use*; D017209:Apoptosis; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism*; D053938:DNA Fragmentation; D004587:Electrophoresis, Agar Gel; D004789:Enzyme Activation; D004792:Enzyme Precursors / Q000378:metabolism; D006801:Humans; D019169:Jurkat Cells / Q000187:drug effects*; D010778:Photochemotherapy
D004792:Enzyme Precursors; D000622:Aminolevulinic Acid; C505407:CASP3 protein, human; D053148:Caspase 3; D020169:Caspases