Mechanism of UV-induced apoptosis in human leukemia cells: roles of Ca2+/Mg(2+)-dependent endonuclease, caspase-3, and stress-activated protein kinases

Exp Cell Res. 1998 Mar 15;239(2):411-22. doi: 10.1006/excr.1997.3912.

Abstract

Ultraviolet light (UV) induced rapid apoptosis of U937 leukemia cells, concurrent with DNA fragmentation and cleavage of poly(ADP-ribose)polymerase (PARP) by activated caspase-3. The in vitro reconstitution of intact HeLa S3 nuclei and apoptotic U937 cytosolic extract (CE) revealed that (i) Ca2+/Mg(2+)-dependent, Zn(2+)-sensitive endonuclease activated in the apoptotic CE induced DNA ladder in HeLa nuclei at pH 6.8-7.4, (ii) activated caspase-3 cleaved PARP in HeLa nuclei, and (iii) when the apoptotic CE was treated with the caspase-3 inhibitor (1 microM Ac-DEVD-CHO) or the caspase-1 inhibitor (10 microM Ac-YVAD-CHO), the former, but not the latter, caused a 50% inhibition of DNA fragmentation and the complete inhibition of PARP cleavage in HeLa nuclei. Similarly, Ac-DEVD-CHO (100 microM) inhibited apoptosis and DNA ladder by 50% and PARP cleavage completely in UV-irradiated U937 cells, but Ac-YVAD-CHO (100 microM) did not. Thus, UV-induced apoptosis of U937 cells involves the Ca2+/Mg(2+)-dependent endonuclease pathway and the caspase-3-PARP cleavage-Ca2+/Mg(2+)-dependent endonuclease pathway. The former pathway produced directly 50% of apoptotic DNA ladder, and the latter involved activated caspase-3 and PARP cleavage, followed by formation of the remaining 50% DNA ladder by the activated endonuclease. In UV-irradiated B-cell lines, further, p53-dependent increase of Bax resulted in a greater caspase-3 activation compared to its absence. However, UV-induced activation of JNK1 and p38 was not affected by the caspase-1 and -3 inhibitors in U937 cells, so that caspases-1 and -3 do not function upstream of JNK1 and p38.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Apoptosis / radiation effects*
  • B-Lymphocytes / enzymology
  • B-Lymphocytes / radiation effects
  • Calcium-Calmodulin-Dependent Protein Kinases / metabolism
  • Caspase 1
  • Caspase 3
  • Caspases*
  • Cysteine Endopeptidases / physiology*
  • Cysteine Proteinase Inhibitors / pharmacology
  • DNA Fragmentation / drug effects
  • DNA, Neoplasm / metabolism
  • Endodeoxyribonucleases / physiology*
  • Enzyme Activation / radiation effects
  • Heat-Shock Proteins / biosynthesis*
  • Heat-Shock Proteins / genetics
  • Humans
  • JNK Mitogen-Activated Protein Kinases
  • Lymphoma, Large B-Cell, Diffuse / enzymology
  • Lymphoma, Large B-Cell, Diffuse / pathology*
  • Mitogen-Activated Protein Kinases*
  • Neoplasm Proteins / physiology*
  • Oligopeptides / pharmacology
  • Poly(ADP-ribose) Polymerases / metabolism
  • Proto-Oncogene Proteins / physiology
  • Proto-Oncogene Proteins c-bcl-2 / physiology
  • Tumor Suppressor Protein p53 / physiology
  • Ultraviolet Rays*
  • bcl-2-Associated X Protein
  • p38 Mitogen-Activated Protein Kinases

Substances

  • BAX protein, human
  • Cysteine Proteinase Inhibitors
  • DNA, Neoplasm
  • Heat-Shock Proteins
  • Neoplasm Proteins
  • Oligopeptides
  • Proto-Oncogene Proteins
  • Proto-Oncogene Proteins c-bcl-2
  • Tumor Suppressor Protein p53
  • acetyl-aspartyl-glutamyl-valyl-aspartal
  • bcl-2-Associated X Protein
  • L 709049
  • Poly(ADP-ribose) Polymerases
  • Calcium-Calmodulin-Dependent Protein Kinases
  • JNK Mitogen-Activated Protein Kinases
  • Mitogen-Activated Protein Kinases
  • p38 Mitogen-Activated Protein Kinases
  • Endodeoxyribonucleases
  • calcium magnesium dependent endodeoxyribonuclease
  • CASP3 protein, human
  • Caspase 3
  • Caspases
  • Cysteine Endopeptidases
  • Caspase 1