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Published on: September 28, 2012

Potentiation of TNF-mediated cell killing by VP-16: relationship to DNA single-strand break formation

D Branellec1, J Markovits, S Chouaib

  • 1Laboratoire d'Immunologie UA1156, Institut Gustave-Roussy, Villejuif, France.

International Journal of Cancer
|December 15, 1990
PubMed

Insights

Tumor necrosis factor (TNF) combined with etoposide (VP-16) enhances cancer cell killing. This combination therapy involves distinct DNA damage pathways, with VP-16 inducing breaks and TNF potentially providing a second signal for cell lysis.

Area of Science:

  • Oncology
  • Molecular Biology
  • Pharmacology

Background:

  • Tumor necrosis factor (TNF) plays a role in cellular apoptosis and immune response.
  • Etoposide (VP-16) is a DNA topoisomerase II inhibitor used in cancer chemotherapy.
  • Understanding the synergistic effects of combined therapies is crucial for developing effective cancer treatments.

Purpose of the Study:

  • To investigate the interaction between TNF and etoposide (VP-16) in cancer cell killing.
  • To elucidate the specific DNA damage mechanisms involved in the combined treatment.
  • To identify potential modulators of this interaction.

Main Methods:

  • Utilized the TNF-sensitive WEHI164.13 murine fibrosarcoma cell line.
  • Employed alkaline DNA filter elution methodology to assess DNA strand breaks.
  • Investigated the effects of phospholipase A2 inhibitors (quinacrine and dexamethasone).

Main Results:

  • Concomitant treatment with TNF and VP-16 significantly enhanced WEHI164.13 cell lysis.
  • TNF alone did not induce DNA single-strand breaks, unlike VP-16.
  • Quinacrine selectively inhibited the combined TNF/VP-16 cell killing pathway by reducing VP-16-induced DNA breaks.

Conclusions:

  • TNF and VP-16 treatments involve distinct mechanisms for cell killing.
  • The synergistic cell lysis induced by VP-16/TNF requires two signals: VP-16-mediated DNA strand breaks and a TNF-dependent signal.
  • Quinacrine abrogates this synergistic effect, highlighting its potential role in modulating combined cancer therapies.

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