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Relevance of the OCT1 transporter to the antineoplastic effect of biguanides

Eric D Segal1, Amber Yasmeen, Marie-Claude Beauchamp

  • 1Division of Gynecologic Oncology, Jewish General Hospital, McGill University, Montreal, Quebec, Canada.

Biochemical and Biophysical Research Communications
|October 12, 2011
PubMed

Insights

Metformin

Area of Science:

  • Oncology
  • Pharmacology
  • Molecular Biology

Background:

  • Epidemiologic and laboratory studies suggest metformin possesses antineoplastic properties.
  • Ongoing clinical trials are investigating metformin's anti-cancer effects.
  • Detailed pharmacokinetic studies, particularly regarding drug uptake, are lacking.

Purpose of the Study:

  • To investigate the role of organic cation transporter 1 (OCT1) in metformin's antineoplastic activity.
  • To compare metformin's efficacy with another biguanide, phenformin, in the context of OCT1 expression.
  • To assess OCT1 expression heterogeneity in primary human tumors.

Main Methods:

  • Utilized siRNA knockdown to reduce OCT1 expression in epithelial ovarian cancer cells.
  • Assessed metformin and phenformin's effects on AMP kinase activation and cell proliferation.
  • Analyzed OCT1 expression levels in primary human tumor samples.

Main Results:

  • siRNA-mediated knockdown of OCT1 significantly reduced sensitivity of ovarian cancer cells to metformin.
  • OCT1 knockdown did not affect sensitivity to phenformin.
  • Observed significant heterogeneity in OCT1 expression across different primary human tumors.
  • Metformin's efficacy was linked to OCT1-mediated cellular uptake.

Conclusions:

  • Organic cation transporter 1 (OCT1) plays a crucial role in mediating metformin's antineoplastic effects in ovarian cancer cells.
  • Drug uptake, influenced by OCT1, can be a limiting factor for metformin's action on neoplastic cells.
  • Metformin may not be the optimal biguanide for all clinical investigations due to variable OCT1 expression.
  • Phenformin may represent an alternative biguanide with potential efficacy independent of OCT1.

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