[New insight into the mechanism of p53 inducing leukemia cell apoptosis]

Zhonghua Xue Ye Xue Za Zhi. 2003 Dec;24(12):640-3.
[Article in Chinese]

Abstract

Objective: To investigate the expression changes of intrinsic cytokines TGF-beta(1) and TNF-alpha, telomerase activity and bcl-2 during ongoing apoptosis of HL-60 and K562 cells induced by p53.

Methods: pN53cG (Val135), a temperature sensitive p53 mutant, which behaved like wild type p53 (wt-p53) at 32.5 degrees C, were introduced into p53-null HL-60 and K562 cells respectively by lipofectin. In the presence of G418, HL-60-pN53cG and K562 pN53cG clones expressing p53 protein were selected. The ongoing expression of intrinsic cytokines (TGF-beta(1) and TNF-alpha), bcl-2 oncogene and hTERT mRNA during the apoptosis of HL-60 and K562 cells induced by p53 and the effects of exogenous p53 gene, TGF-beta(1) and TNF-alpha antisense PS-ODNS on the apoptosis of HL-60 and K562 cells and the expression of bcl-2 were studied by RT-PCR, quantitative RT-PCR, DNA fragmentation, TdT-mediated dUTP nick end labeling (TUNEL) and flow cytometery. The levels of secreted TGF-beta(1) and telomerase activity were detected by ELISA and PCR-ELISA, respectively.

Results: (1) The expressions of intrinsic TGF-beta(1) and TNF-alpha mRNA were up-regulated, while that of bcl-2 and hTERT down-regulated. The levels of TGF-beta(1) in the supernatant of HL-60 and K562 cells were increased, and the level of telomerase activity decreased. (2) Antisense PS-ODNS of TGF-beta(1) and TNF-alpha could obviously inhibit the p53 inducing cell apoptosis, and restore bcl-2 mRNA and protein to pre-treated level.

Conclusions: Exogenous p53 induces leukemia cell apoptosis via up-regulating the expression of intrinsic TGF-beta(1) and TNF-alpha and down-regulating the expression of hTERT and bcl-2.

Publication types

  • English Abstract
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Apoptosis / drug effects
  • Apoptosis / genetics*
  • DNA, Antisense / pharmacology
  • DNA-Binding Proteins
  • Gene Expression Regulation, Neoplastic
  • HL-60 Cells
  • Humans
  • K562 Cells
  • Leukemia / genetics
  • Leukemia / pathology
  • Mutation
  • Plasmids / genetics
  • Proto-Oncogene Proteins c-bcl-2 / genetics
  • RNA, Messenger / drug effects
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Reverse Transcriptase Polymerase Chain Reaction
  • Telomerase / genetics
  • Transfection / methods
  • Transforming Growth Factor beta / genetics
  • Transforming Growth Factor beta1
  • Tumor Necrosis Factor-alpha / genetics
  • Tumor Suppressor Protein p53 / genetics
  • Tumor Suppressor Protein p53 / physiology*

Substances

  • DNA, Antisense
  • DNA-Binding Proteins
  • Proto-Oncogene Proteins c-bcl-2
  • RNA, Messenger
  • TGFB1 protein, human
  • Transforming Growth Factor beta
  • Transforming Growth Factor beta1
  • Tumor Necrosis Factor-alpha
  • Tumor Suppressor Protein p53
  • Telomerase