{Beta}2-adrenergic receptor agonists inhibit the proliferation of 1321N1 astrocytoma cells

J Pharmacol Exp Ther. 2011 Feb;336(2):524-32. doi: 10.1124/jpet.110.173971. Epub 2010 Nov 11.

Abstract

Astrocytomas and glioblastomas have been particularly difficult to treat and refractory to chemotherapy. However, significant evidence has been presented that demonstrates a decrease in astrocytoma cell proliferation subsequent to an increase in cAMP levels. The 1321N1 astrocytoma cell line, as well as other astrocytomas and glioblastomas, expresses β(2)-adrenergic receptors (β(2)-ARs) that are coupled to G(s) activation and consequent cAMP production. Experiments were conducted to determine whether the β(2)-AR agonist (R,R')-fenoterol and other β(2)-AR agonists could attenuate mitogenesis and, if so, by what mechanism. Receptor binding studies were conducted to characterize β(2)-AR found in 1321N1 and U118 cell membranes. In addition, cells were incubated with (R,R')-fenoterol and analogs to determine their ability to stimulate intracellular cAMP accumulation and inhibit [(3)H]thymidine incorporation into the cells. 1321N1 cells contain significant levels of β(2)-AR as determined by receptor binding. (R,R')-fenoterol and other β(2)-AR agonists, as well as forskolin, stimulated cAMP accumulation in a dose-dependent manner. Accumulation of cAMP induced a decrease in [(3)H]thymidine incorporation. There was a correlation between concentration required to stimulate cAMP accumulation and inhibit [(3)H]thymidine incorporation. U118 cells have a reduced number of β(2)-ARs and a concomitant reduction in the ability of β(2)-AR agonists to inhibit cell proliferation. These studies demonstrate the efficacy of β(2)-AR agonists for inhibition of growth of the astrocytoma cell lines. Because a significant portion of brain tumors contain β(2)-ARs to a greater extent than whole brain, (R,R')-fenoterol, or some analog, may be useful in the treatment of brain tumors after biopsy to determine β(2)-AR expression.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adrenergic beta-2 Receptor Agonists / pharmacology*
  • Astrocytoma / drug therapy*
  • Astrocytoma / pathology
  • Cell Line, Tumor
  • Cell Proliferation / drug effects
  • Cyclic AMP / metabolism
  • Fenoterol / pharmacology
  • G1 Phase / drug effects
  • Humans
  • Propanolamines / metabolism
  • Thymidine / metabolism

Substances

  • Adrenergic beta-2 Receptor Agonists
  • Propanolamines
  • Fenoterol
  • Cyclic AMP
  • CGP 12177
  • Thymidine