Effects of menadione, hydrogen peroxide, and quercetin on apoptosis and delayed luminescence of human leukemia Jurkat T-cells.
Menadione (MD) is an effective cytotoxic drug able to produce intracellularly large amounts of superoxide anion. Quercetin (QC), a widely distributed bioflavonoid, can exert both antioxidant and pro-oxidant effects and is known to specifically inhibit cell proliferation and induce apoptosis in different cancer cell types. We have investigated the relation between delayed luminescence (DL) induced by UV-laser excitation and the effects of MD, hydrogen peroxide, and QC on apoptosis and cell cycle in human leukemia Jurkat T-cells. Treatments with 500 μM H₂O₂ and 250 μM MD for 20 min produced 66.0 ± 4.9 and 46.4 ± 8.6% apoptotic cell fractions, respectively. Long-term (24 h) pre-exposure to 5 μM, but not 0.5 μM QC enhanced apoptosis induced by MD, whereas short-term (1 h) pre-incubation with 10 μM QC offered 50% protection against H₂O₂-induced apoptosis, but potentiated apoptosis induced by MD. Since physiological levels of QC in the blood are normally less than 10 μM, these data can provide relevant information regarding the benefits of flavonoid-combined treatments of leukemia. All the three drugs exerted significant effects on DL. Our data are consistent with (1) the involvement of Complex I of the mitochondrial respiratory chain as an important source of delayed light emission on the 10 μs-10 ms scale, (2) the ability of superoxide anions to quench DL on the 100 μs-10 ms scale, probably via inhibition of reverse electron transfer at the Fe/S centers in Complex I, and (3) the relative insensitivity of DL to intracellular OH• and H₂O₂ levels.
Baran
Irina
I
Department of Biophysics, Carol Davila University of Medicine and Pharmacy, 8 Eroii Sanitari, Bucharest, Romania. baran@ifin.nipne.ro
Ganea
Constanta
C
Scordino
Agata
A
Musumeci
Francesco
F
Barresi
Vincenza
V
Tudisco
Salvatore
S
Privitera
Simona
S
Grasso
Rosaria
R
Condorelli
Daniele F
DF
Ursu
Ioan
I
Baran
Virgil
V
Katona
Eva
E
Mocanu
Maria-Magdalena
MM
Gulino
Marisa
M
Ungureanu
Raluca
R
Surcel
Mihaela
M
Ursaciuc
Cornel
C
D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D018797:Cell Cycle Proteins / Q000378:metabolism; D005434:Flow Cytometry; D006801:Humans; D006861:Hydrogen Peroxide / Q000633:toxicity*; D019169:Jurkat Cells; D007700:Kinetics; D007938:Leukemia / Q000188:drug therapy / Q000473:pathology; D011794:Quercetin / Q000494:pharmacology*; D013050:Spectrometry, Fluorescence; D024483:Vitamin K 3 / Q000494:pharmacology*
D000970:Antineoplastic Agents; D018797:Cell Cycle Proteins; D024483:Vitamin K 3; D011794:Quercetin; D006861:Hydrogen Peroxide