These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Reduction in the radiation-induced late S phase and G2 blocks in HL-60 cell populations by amiloride, an efficient inhibitor of the Na+/H+ transporter.
    Author: Sailer BL, Barrasso AM, Valdez JG, Cobo JM, D'Anna JA, Crissman HA.
    Journal: Cancer Res; 1998 Feb 01; 58(3):413-20. PubMed ID: 9458082.
    Abstract:
    Recent investigations that showed that amiloride delayed or inhibited apoptosis indicated it might also attenuate cell cycle checkpoints activated by ionizing radiation. In this report, single- and dual-parameter flow cytometry were used to investigate the effects of amiloride on cell cycle progression, and the effectiveness of amiloride to attenuate the S and G2 phase checkpoint responses induced by 2.5, 5.0, and 7.5 Gy of gamma radiation. The late S-phase delay, noted at 8 h following irradiation, and a radiation-induced G2 block, which was maximum at 16 h after irradiation, were both significantly reduced in amiloride-treated samples. Attenuation of the radiation-induced late S phase and G2 blocks resulted in cell division without apparent apoptosis or necrosis over a 24-h period. Results presented indicate that amiloride reduces the radiation-induced G2 block in HL-60 cell populations almost equally well as caffeine and to a greater extent than staurosporine. Immunofluorescent detection and quantitation of cyclin B1 expression demonstrated that amiloride only significantly reduced cyclin B1 expression following 5.0 Gy, when there was a notable induction of a significant G2 delay, followed by a relatively rapid recovery in cycling potential. The results suggest that amiloride affects the radiation-triggered signaling cascades to alter the kinase activity of proteins associated with mitotic progression, particularly the cyclin B1-p34cdc2 complex. Alternatively, alterations in intracellular ion concentrations induced by amiloride may lead to changes in Ca2+-dependent signaling cascades and thereby decrease the radiation-mediated cell cycle perturbations.
    [Abstract] [Full Text] [Related] [New Search]