Regular paper
Characterisation of pentamidine-resistant Trypanosoma brucei brucei

https://doi.org/10.1016/0166-6851(94)00215-9Get rights and content

Abstract

Following selection in vitro by exposure to increasing concentrations of the aromatic diamidine pentamidine, a Trypanosoma brucei brucei clone has been characterised in vivo and in vitro. The resistant clone, designated T.b. brucei S427/118/PR32.6, was found to be less virulent than the parental clone T.b. brucei S427118, with an intraperitoneal injection of 2.5 × 106 resistant organisms required to produce a course of disease equivalent to 1 × 104 sensitive trypanosomes. This lowered virulence is not associated with an increased susceptibility to the host's immune system, and is not due to the in vitro culturing process. The pentamidine-resistant clone was found to be 26- and 4.5-fold resistant to pentamidine in vitro and in vivo, respectively. Although not cross-resistant in vivo to any other aromatic diamidines (stilbamidine, berenil and propamidine), a 2.4-fold increase in resistance to the melaminophenylarsine melarsoprol was observed. While pentamidine completely inhibited uptake of 1 μM [3H]adenosine in the presence of 1 mM inosine, suggesting that pentamidine is transported by the inosine-insensitive P2 transporter, the pentamidine-resistant clone appeared to have a fully functional P2-adenosine transport system. Both resistant and parental cloned lines accumulated approx. 6 nmol pentamidine (108 cells)−1 over the course of 3 h, representing an internal concentration of 0.7–1.0 mM. Thus, unlike previously characterised drug-resistant trypanosomes, T.b. brucei PR32.6 is not deficient in drug accumulation, suggesting that other resistance mechanisms are likely to be involved.

References (37)

  • J.N. Ashley et al.

    A chemotherapeutic comparison of the trypanocidal action of some aromatic diamidines

    J. Chem. Soc. Chem. Commun.

    (1942)
  • M. Sands et al.

    Pentamidine: a review

    Rev. Infect. Dis.

    (1985)
  • J.E. Kapusnik et al.

    Pentamidine

  • S.L. Croft et al.

    Effect of pentamidine isethionate on the ultrastructure and morphology of Leishmania mexicana amazonensis in vitro

    Ann. Trop. Med. Parasitol.

    (1982)
  • A.J. Bitonti et al.

    Characterization of Trypanosoma brucei brucei S-adenosyl-l-methionine decarboxylase and its inhibition by Berenil, pentamidine and methylglyoxal bis(guanylhydrazone)

    Biochem. J.

    (1986)
  • T.A. Shapiro et al.

    Selective cleavage of kinetoplast DNA minicircles promoted by antitrypanosomal drugs

  • A.E. Vercesi et al.

    Ca2+ transport by digitonin-permeabilized Leishmania donovani. Effects of Ca2+, pentamidine and WR-6026 on mitochondrial membrane potential in situ

    Biochem. J.

    (1992)
  • T.P. Waalkes et al.

    Pharmacological aspects of pentamidine

    Natl. Cancer Inst. Monogr. 43

    (1976)
  • Cited by (0)

    1

    Present address: The Picower Institute for Medical Research, 350 Community Drive, Manhasset, NY 11030, USA.

    2

    Present address: Department of Biochemistry, Oregon Health Sciences University, 3181 S.W. Sam Jackson Park Road, Portland, OR 97201, USA.

    View full text