Вавиловский журнал генетики и селекции (Dec 2016)

Development of the therapeutic regimen based on the synergistic activity of cyclophosphamide and double-stranded DNA preparation which results in complete cure of mice engrafted with Krebs-2 ascites

  • E. A. Potter,
  • E. V. Dolgova,
  • A. S. Proskurina,
  • Ya. R. Efremov,
  • O. S. Taranov,
  • V. P. Nikolin,
  • N. A. Popova,
  • T. D. Dubatolova,
  • D. D. Petrova,
  • E. I. Vereschagin,
  • A. M. Minkevich,
  • O. M. Andrushkevich,
  • S. I. Baiborodin,
  • V. A. Rogachev,
  • A. A. Ostanin,
  • E. R. Chernykh,
  • N. A. Kolchanov,
  • S. S. Bogachev

DOI
https://doi.org/10.18699/VJ16.162
Journal volume & issue
Vol. 20, no. 5
pp. 723 – 735

Abstract

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Cumulative evidence obtained in this series of studies has guided the logic behind the development of a novel composite dsDNA-based preparation whose therapeutic application according to the specific regimen completely cures the mice engrafted with otherwise lethal Krebs-2 ascites. The likely mechanism involves elimination of TAMRA+ tumor-inducing stem cells (TISCs) from Krebs-2 tumors. We performed quantitative analysis of TISC dynamics in Krebs-2 ascites following treatment with the cytostatic drug cyclophosphamide (CP) and untreated control cells. In intact ascites, TISC percentage oscillates around a certain value. Following CP treatment and massive apoptosis of committed cancer cell subpopulation, we observed relative increase in TISC percentage, which is consistent with reduced susceptibility of TISCs to CP. Nonetheless, this treatment apparently synchronizes TISCs in a cell cycle phase when they become sensitive to further drug treatments. We describe the regimen of synergistic DNA + CP activity against Krebs-2 ascites. This protocol results in a complete cure of 50 % of Krebs-2 engrafted mice and involves three metronomic injections of CP exactly at the timepoints when repair cycles are about to finish combined with dsDNA injections 18 hours following each CP injection. The “final shot” uses CP + DNA treatment, which targets the surviving yet highly synchronized and therefore treatmentsensitive cells. The first three CP/DNA injections appear to arrest Krebs-2 cells in late S-G2-M phase and result in their simultaneous progression into G1-S phase. The timing of the “final shot” is crucial for the successful treatment, which eradicates tumorigenic cell subpopulation from Krebs-2 ascites. Additionally, we quantified the changes in several biochemical, cellular and morphopathological parameters in mice throughout different treatment stages.

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