Lipids

, Volume 33, Issue 3, pp 295–301

Cytotoxicity of tocopherols and their quinones in drug-sensitive and multidrug-resistant leukemia cells

  • David G. Cornwell
  • Kenneth H. Jones
  • Zongcheng Jiang
  • Laura E. Lantry
  • Peter Southwell-Keely
  • Indrajati Kohar
  • Donald E. Thornton
Article

DOI: 10.1007/s11745-998-0208-8

Cite this article as:
Cornwell, D.G., Jones, K.H., Jiang, Z. et al. Lipids (1998) 33: 295. doi:10.1007/s11745-998-0208-8

Abstract

Cytotoxicities of tocopherols (α-T, γ-T, δ-T), their para (α-TQ, γ-TQ, δ-TQ)-and ortho (Tocored)-quinone oxidation products, the synthetic quinone analog of γ-TQ containing a methyl group substituted for the phytyl side-chain (TMCQ) and the synthetic quinone analog of Tocored containing a methyl group substituted for the phytyl side-chain (PR) were measured in acute lymphoblastic leukemia cell lines that are drug-sensitive (CEM) and multidrug-resistant (CEM/VLB100). Among tocopherols, only δ-T exhibited cytotoxicity. Among para quinones, α-TQ showed no cytotoxicity, while γ-TQ and δ-TQ were highly cytotoxic in both CEM and CEM/VLB100 cell lines (LD50<10 μM). δ-TQ and γ-TQ were more cytotoxic than the widely studied chemotherapeutic agent doxorubicin, which also showed selective cytotoxicity to CEM cells. The orthoquinone Tocored was less cytotoxic than doxorubicin in drug-sensitive cells but more cytotoxic than doxorubicin in multidrug-resistant cells. Cytotoxicity was not a function of the phytyl side-chain since both TMCQ and PR were cytotoxic in leukemia cells. Cytotoxic para and ortho quinones were electrophiles that formed adducts with nucleophilic thiol groups in glutathione and 2-mercaptoethanol. Cytotoxicity was enhanced when the glutathione pool was depleted by preincubation with buthionine-[S,R]-sulfoximine, but cytotoxicity was diminished by the addition of N-acetylcysteine to cultures. α-T also diminished the cytotoxicity of para- and or-thoquinones. Buthionine-[S,R]-sulfoximine did not block the inhibitory effect of either N-acetylcysteine or α-T, showing that these agents did not act solely by maintaining the glutathione pool as an essential antioxidant system. In conclusion, tocopherylquinones represent a new class of alkylating electrophilic quinones that function as highly cytotoxic agents and escape multidrug resistance in acute lymphoblastic leukemia cell lines.

Abbreviations

ANOVA

analysis of variance

BSO

buthionine-[S,R]-sulfoximine

CEM

drug-sensitive lymphoblastic leukemia cells

CEM/VLB100

multidrug-resistant lymphoblastic leukemia cells

FAB MS

fast atom bombardment mass spectrometry

HPLC

high-performance liquid chromatography

MTT

3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide

NAC

N-acetylcysteine

PR

2,2,7,8-tetramethylchroman-5,6-dione

α-T, δ-T

and γ-T, α-, δ- and γ-tocopherol

TLC

thin-layer chromatography

TMCQ

2-(3-hydroxy-3-methylbutyl)-5,6-dimethyl-1,4-benzoquinone

Tocored

2,7,8-trimethyl-2-(4,8,12-trimethyldecyl)0chroman-5,6-dione

TQ

tocopheryl quinone

α-TQ

γ-TQ, and δ-TQ, α-, γ-, and δ-tocopheryl quinone

Copyright information

© AOCS Press 1998

Authors and Affiliations

  • David G. Cornwell
    • 1
  • Kenneth H. Jones
    • 2
  • Zongcheng Jiang
    • 3
  • Laura E. Lantry
    • 4
  • Peter Southwell-Keely
    • 5
  • Indrajati Kohar
    • 6
  • Donald E. Thornton
    • 4
  1. 1.Department of Medical BiochemistryThe Ohio State UniversityColumbus
  2. 2.Department of Cell Biology/Neurobiology/AnatomyThe Ohio State UniversityColumbus
  3. 3.Department of RadiologyThe Ohio State UniversityColumbus
  4. 4.Internal MedicineThe Ohio State UniversityColumbus
  5. 5.Department of Organic ChemistryThe University of New South WalesSydneyAustralia
  6. 6.Faculty of PharmacyUniversity of SurabayaJawa TimorIndonesia