Toxins (Feb 2013)

Shiga Toxin 1, as DNA Repair Inhibitor, Synergistically Potentiates the Activity of the Anticancer Drug, Mafosfamide, on Raji Cells

  • Piero Sestili,
  • Pier Giorgio Petronini,
  • Roberta R. Alfieri,
  • Pier Luigi Tazzari,
  • Francesca Ricci,
  • Pasqualepaolo Pagliaro,
  • Laura Rocchi,
  • Cinzia Calcabrini,
  • Maurizio Brigotti,
  • Valentina Arfilli,
  • Domenica Carnicelli

DOI
https://doi.org/10.3390/toxins5020431
Journal volume & issue
Vol. 5, no. 2
pp. 431 – 444

Abstract

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Shiga toxin 1 (Stx1), produced by pathogenic Escherichia coli, targets a restricted subset of human cells, which possess the receptor globotriaosylceramide (Gb3Cer/CD77), causing hemolytic uremic syndrome. In spite of the high toxicity, Stx1 has been proposed in the treatment of Gb3Cer/CD77-expressing lymphoma. Here, we demonstrate in a Burkitt lymphoma cell model expressing this receptor, namely Raji cells, that Stx1, at quasi-non-toxic concentrations (0.05–0.1 pM), inhibits the repair of mafosfamide-induced DNA alkylating lesions, synergistically potentiating the cytotoxic activity of the anticancer drug. Conversely, human promyelocytic leukemia cells HL-60, which do not express Gb3Cer/CD77, were spared by the toxin as previously demonstrated for CD34+ human progenitor cells, and hence, in this cancer model, no additive nor synergistic effects were observed with the combined Stx1/mafosfamide treatment. Our findings suggest that Stx1 could be used to improve the mafosfamide-mediated purging of Gb3Cer/CD77+ tumor cells before autologous bone marrow transplantation.

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