Evaluation of gambierol and its analogs for their inhibition of human Kv1.2 and cytotoxicity

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Abstract

Gambierol and its heptacyclic and tetracyclic analogs were tested for inhibitory activity against the human voltage-gated potassium channel Kv1.2 (hKv1.2), which was stably expressed in Chinese hamster ovary (CHO) cells. Gambierol, the heptacyclic analog, and the tetracyclic analog inhibited the potassium current evoked by a step pulse from −80 mV to 40 mV. The IC50 values for the three compounds were 0.75 ± 0.15 nM, 7.6 ± 1.2 nM, and 28 ± 4.0 nM (the mean ± SEM, n = 3), respectively. The cytotoxic activity was examined in order to assess a relationship between cytotoxicity and inhibition of the hKv1.2. The IC50 values for gambierol, the heptacyclic analog, and the tetracyclic analog in the wild-type CHO cells were 95 ± 7.1 μM, 6.5 ± 0.8 μM (the mean ± SEM, n = 3), and >100 μM (n = 3), respectively, whereas those in the CHO cells stably expressing hKv1.2 were 78 ± 5.8 μM, 6.0 ± 1.0 μM (the mean ± SEM, n = 3), and >100 μM (n = 3). These results suggested that cytotoxicity is not triggered by inhibition of the human Kv1.2. The electrophysiological recording at the resting potential in the presence of gambierol, the heptacyclic analog, and the tetracyclic analog revealed the dose-dependent leak current, which was largest when the heptacyclic analog was administered to the cells. We thus propose that the leak current induced by these compounds might cause a fatal effect on the cultured cells.

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Acknowledgments

The research studies were funded by the ERATO Murata Lipid Active Structure Project, Japan Science and Technology Agency, a Grant-in-Aid for Scientific Research on Innovative Areas ‘Chemical Biology of Natural Products’ from the Ministry of Education, Culture, Sports, Science and Technology (MEXT), Japan64 (M. S., and K. K.), and the Japan Society for the Promotion of Science for Funding Program for the Next Generation World-Leading Researchers (LS012) (M. Y. Y.).

We thank Takayuki Oka and

References and notes (64)

  • M. Satake et al.

    Tetrahedron Lett.

    (2002)
  • M. Murata et al.

    Tetrahedron Lett.

    (1987)
  • J.P. Naar et al.

    Toxicon

    (2007)
  • V.L. Trainer et al.

    J. Biol. Chem.

    (1994)
  • A. Lombet et al.

    FEBS Lett.

    (1987)
  • D.G. Baden et al.

    Toxicon

    (1982)
  • M. Inoue et al.

    Toxicon

    (2003)
  • M. Takahashi et al.

    J. Biol. Chem.

    (1982)
  • F. Gusovsky et al.

    FEBS Lett.

    (1989)
  • M. Taglialatela et al.

    Brain Res.

    (1986)
  • J.F. Worley et al.

    J. Biol. Chem.

    (1994)
  • M. Nishio et al.

    Eur. J. Pharmacol.

    (1996)
  • A. Alfonso et al.

    Biochem. Pharmacol.

    (2003)
  • R. Mouri et al.

    Bioorg. Med. Chem. Lett.

    (2009)
  • S. Ujihara et al.

    Bioorg. Med. Chem. Lett.

    (2010)
  • C. Tsukano et al.

    Tetrahedron Lett.

    (2006)
  • H. Fuwa et al.

    Bioorg. Med. Chem. Lett.

    (2003)
  • S. Schlumberger et al.

    Toxicon

    (2010)
  • E. Cuypers et al.

    Toxicon

    (2008)
  • I. Kopljar et al.

    Toxicon

    (2012)
  • K. Yamaoka et al.

    J. Biol. Chem.

    (2009)
  • S. Matile et al.

    Chem. Biol.

    (1996)
  • Y. Shimizu et al.

    J. Am. Chem. Soc.

    (1986)
  • Y.Y. Lin et al.

    J. Am. Chem. Soc.

    (1981)
  • M. Murata et al.

    J. Am. Chem. Soc.

    (1989)
  • M. Murata et al.

    J. Am. Chem. Soc.

    (1990)
  • H. Nagai et al.

    J. Am. Chem. Soc.

    (1992)
  • H. Nagai et al.

    J. Org. Chem.

    (1992)
  • M. Murata et al.

    J. Am. Chem. Soc.

    (1993)
  • M. Murata et al.

    J. Am. Chem. Soc.

    (1994)
  • M. Satake et al.

    J. Am. Chem. Soc.

    (1995)
  • T. Igarashi et al.

    J. Am. Chem. Soc.

    (1996)
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