Open Access

Suppression of HIF-1α expression and radiation resistance in acute hypoxic conditions

  • Authors:
    • Takahiro Oike
    • Yoshiyuki Suzuki
    • Wael Al-Jahdari
    • Abdulelah Mobaraki
    • Jun‑Ichi Saitoh
    • Kohta Torikai
    • Katsuyuki Shirai
    • Takashi Nakano
  • View Affiliations

  • Published online on: October 21, 2011     https://doi.org/10.3892/etm.2011.373
  • Pages: 141-145
Metrics: Total Views: 0 (Spandidos Publications: | PMC Statistics: )
Total PDF Downloads: 0 (Spandidos Publications: | PMC Statistics: )


Abstract

Recently, it has become clear that acute hypoxia affecting radioresistance exists widely in tumor tissues. Concurrently, hypoxia-inducible factor-1α (HIF-1α) is recognized as an essential transcriptional factor, enabling cells to survive through hypoxia. However, it is unclear as to whether HIF-1α plays a direct role in the radioresistance caused by acute hypoxia. Therefore, in this study, we investigated the in vitro response of the human lung adenocarcinoma cell line, A549, to ionizing radiation in an experimental model that imitates acute hypoxia in the presence and absence of HIF-1α expression, using the HIF-1α inhibitor 5-[1‑(phenylmethyl)‑1H‑indazol‑3-yl]‑2-furanmethanol (YC-1). Cells were treated with or without 10 µM YC-1 for 2 h. Cells were exposed to either 95% N2 and 5% CO2 (hypoxic condition of <0.1 mmHg) or atmospheric air (normoxic condition) for 1 h, and irradiated with 2, 5 and 10 Gy. Western blot analysis revealed that, without YC-1, cells exposed to hypoxic conditions expressed increased levels of HIF-1α compared with those exposed to normoxic conditions. Under hypoxic conditions, HIF-1α expression was suppressed by YC-1 to the same extent as that observed in cells exposed to normoxic conditions without YC-1. Clonogenic survival assay revealed that under hypoxic conditions there was no significant difference between the surviving fraction of cells treated with YC-1 and without YC-1 at any dose point examined. The oxygen enhancement ratio at 10% surviving fraction was calculated as 2.7 and 2.6 in the presence and the absence of YC-1, respectively. These results indicate that HIF-1α itself is not an immediate cause of acute hypoxia-induced radioresistance in A549 cells.
View Figures
View References

Related Articles

Journal Cover

January 2012
Volume 3 Issue 1

Print ISSN: 1792-0981
Online ISSN:1792-1015

Sign up for eToc alerts

Recommend to Library

Copy and paste a formatted citation
x
Spandidos Publications style
Oike T, Suzuki Y, Al-Jahdari W, Mobaraki A, Saitoh JI, Torikai K, Shirai K and Nakano T: Suppression of HIF-1α expression and radiation resistance in acute hypoxic conditions. Exp Ther Med 3: 141-145, 2012
APA
Oike, T., Suzuki, Y., Al-Jahdari, W., Mobaraki, A., Saitoh, J., Torikai, K. ... Nakano, T. (2012). Suppression of HIF-1α expression and radiation resistance in acute hypoxic conditions. Experimental and Therapeutic Medicine, 3, 141-145. https://doi.org/10.3892/etm.2011.373
MLA
Oike, T., Suzuki, Y., Al-Jahdari, W., Mobaraki, A., Saitoh, J., Torikai, K., Shirai, K., Nakano, T."Suppression of HIF-1α expression and radiation resistance in acute hypoxic conditions". Experimental and Therapeutic Medicine 3.1 (2012): 141-145.
Chicago
Oike, T., Suzuki, Y., Al-Jahdari, W., Mobaraki, A., Saitoh, J., Torikai, K., Shirai, K., Nakano, T."Suppression of HIF-1α expression and radiation resistance in acute hypoxic conditions". Experimental and Therapeutic Medicine 3, no. 1 (2012): 141-145. https://doi.org/10.3892/etm.2011.373