Bcl-2 phosphorylation in a human breast carcinoma xenograft: A common event in response to effective DNA-damaging drugs

Graziella Pratesi, Donatella Polizzi, Paola Perego, Laura Dal Bo, Franco Zunino

Research output: Contribution to journalArticlepeer-review


A variety of cytotoxic agents effective as antitumor drugs are known to kill tumor cells through induction of apoptosis as the most relevant modality of cell death. A specific role for the protein Bcl-2 in the cell death pathway induced by antimicrotubule agents has been proposed, because Bcl-2 phosphorylation occurs in response to microtubule damage. In this study, we compared efficacy, apoptosis, and Bcl-2 phosphorylation in the Bcl-2-overexpressing MX-1 human breast carcinoma xenograft after treatment with cytotoxic agents characterized by different mechanisms of action. We demonstrated that, in addition to antimicrotubule agents, effective DNA-damaging agents were also able to induce Bcl-2 phosphorylation irrespective of the type of genotoxic lesion. A comparison of effects of drugs belonging to the same class but endowed with a different antitumor activity (i.e. cisplatin versus a novel multinuclear platinum complex and doxorubicin versus a disaccharide analogue) showed a correlation between drug efficacy, apoptotic response, and Bcl-2 phosphorylation. In conclusion, overexpression of Bcl-2 did not counteract the apoptotic effects of a number of cytotoxic agents and could not be regarded as a mechanism of cellular resistance. Since Bcl-2 phosphorylation is a common event in response to different types of cytotoxic damage and is not only related to microtubule dysfunction, we suggest that many cell death pathways converge on Bcl-2 and protein phosphorylation is a step of the signaling cascade activated by diverse stimuli and likely related to the onset of drug-induced apoptosis. Copyright (C) 2000 Elsevier Science Inc.

Original languageEnglish
Pages (from-to)77-82
Number of pages6
JournalBiochemical Pharmacology
Issue number1
Publication statusPublished - Jul 2000


  • Anthracycline
  • Apoptosis
  • Bcl-2
  • Cisplatin
  • Taxane
  • Tumor xenografts

ASJC Scopus subject areas

  • Pharmacology


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