X-irradiation enhances the expression of Bcl-2 in HL-60 cells: the resulting effects on apoptosis and radiosensitivity.

  • Authors:
    • S Kariya
    • Y Ogawa
    • S Yoshida
    • M Yabuki
    • Y Imajo
    • K Utsumi
  • View Affiliations

  • Published online on: February 1, 1999     https://doi.org/10.3892/ijmm.3.2.145
  • Pages: 145-197
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Abstract

Although p53 has been shown to directly activate transcriptional bax gene and to inhibit expression of bcl-2 gene during radiation-induced apoptosis, it is poorly understood how the Bcl-2 family changes in p53-deficient cells during radiation-induced apoptosis. The present work describes the effect of X-irradiation on the apoptosis of p53-deficient HL-60 cells as assessed by means of several methods. Apoptosis of HL-60 cells was induced by X-irradiation in a dose- and time-dependent manner. 18 h after 5 Gy irradiation, G2 cells underwent apoptosis, while 15 Gy X-irradiation induced the death of G1/S cells by 6 h. After X-irradiation, expression of Bcl-2 was elevated, while Bax expression was unchanged. We have isolated a clonal HL-60 variant following twice 5 Gy irradiation of HL-XR3 cells. These cells highly expressed Bcl-2 (about 2-fold), showed a reduced activation of caspase-3, and were not only more resistant to X-irradiation-induced apoptosis but also more radioresistant. These results suggest that HL-60 cells may resist apoptosis and radiation by increasing Bcl-2 expression, and that this elevated Bcl-2 expression might be one of the causes of the phenomenon, often seen clinically, that tumor cells gradually acquire radioresistance during fractionated radiation therapy.

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Feb 1999
Volume 3 Issue 2

Print ISSN: 1107-3756
Online ISSN:1791-244X

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Spandidos Publications style
Kariya S, Ogawa Y, Yoshida S, Yabuki M, Imajo Y and Utsumi K: X-irradiation enhances the expression of Bcl-2 in HL-60 cells: the resulting effects on apoptosis and radiosensitivity.. Int J Mol Med 3: 145-197, 1999
APA
Kariya, S., Ogawa, Y., Yoshida, S., Yabuki, M., Imajo, Y., & Utsumi, K. (1999). X-irradiation enhances the expression of Bcl-2 in HL-60 cells: the resulting effects on apoptosis and radiosensitivity.. International Journal of Molecular Medicine, 3, 145-197. https://doi.org/10.3892/ijmm.3.2.145
MLA
Kariya, S., Ogawa, Y., Yoshida, S., Yabuki, M., Imajo, Y., Utsumi, K."X-irradiation enhances the expression of Bcl-2 in HL-60 cells: the resulting effects on apoptosis and radiosensitivity.". International Journal of Molecular Medicine 3.2 (1999): 145-197.
Chicago
Kariya, S., Ogawa, Y., Yoshida, S., Yabuki, M., Imajo, Y., Utsumi, K."X-irradiation enhances the expression of Bcl-2 in HL-60 cells: the resulting effects on apoptosis and radiosensitivity.". International Journal of Molecular Medicine 3, no. 2 (1999): 145-197. https://doi.org/10.3892/ijmm.3.2.145