A point mutation of human p53, which was not detected as a mutation by a yeast functional assay, led to apoptosis but not p21(Waf1/Cip1/Sdi1) expression in response to ionizing radiation in a human osteosarcoma cell line, Saos-2

Kumio Okaichi, Li Hong Wang, Ji ichiro Sasaki, Hideyuki Saya, Mitsuhiro Tada, Yutaka Okumura

Research output: Contribution to journalArticle

18 Citations (Scopus)

Abstract

Purpose: The 123A point mutation of p53 showed increased radiosensitivity, whereas other mutations (143A, 175H, and 273H) were not affected. To determine the reason for increased radiosensitivity of the 123A mutation, the response of the transformant of 123A mutation to ionizing radiation (IR) was examined and compared to those of transformants with the wild type p53 or other point mutations (143A, 175H, and 273H).Methods and Materials: Stable transformants with a mutant or wild type p53 made by introducing cDNA into the human osteosarcoma cell line, Saos-2, which lacks an endogenous p53 were used. The transcriptional activity of mutant p53 was examined using a yeast functional assay. The transformants were examined for the accumulation of p53, the induction of p21(Waf1/Cip1/Sdi1) (hereafter referred to as p21), and the other response of p53-responsive genes (MDM2, Bax, and Bcl-2) by Western blotting. Apoptosis was analyzed by detection of DNA fragmentation.Results: The 123A point mutation of p53 was detected as a wild type in the yeast functional assay. The 123A mutant accumulated p53 in response to IR. The 123A mutant did not induce p21, but normally responded to MDM2, Bax, and Bcl-2. The 123A mutant entered apoptosis earlier than the wild type p53 transformant, and induced Fas at earlier in response to IR.Conclusion: The 123A mutant led to apoptosis, but not p21 expression in response to IR. The occurrence of apoptosis, but not induction of p21, corresponded to the radiosensitivity in the transformant. The early occurrence of apoptosis in 123A transformants may depend on the early induction of Fas. Copyright (C) 1999 Elsevier Science Inc.

Original languageEnglish
Pages (from-to)975-980
Number of pages6
JournalInternational Journal of Radiation Oncology Biology Physics
Volume45
Issue number4
DOIs
Publication statusPublished - 1999 Nov 1
Externally publishedYes

Fingerprint

yeast
apoptosis
Osteosarcoma
mutations
Ionizing Radiation
Point Mutation
cultured cells
ionizing radiation
Yeasts
Apoptosis
Radiation Tolerance
Cell Line
Mutation
radiation tolerance
induction
occurrences
p53 Genes
DNA Fragmentation
genes
Complementary DNA

Keywords

  • Apoptosis
  • Ionizing radiation
  • Mutant p53
  • p21
  • Yeast functional assay

ASJC Scopus subject areas

  • Oncology
  • Radiology Nuclear Medicine and imaging
  • Radiation

Cite this

@article{fb124f0e2c2a4a9cb48f3694533e6cfe,
title = "A point mutation of human p53, which was not detected as a mutation by a yeast functional assay, led to apoptosis but not p21(Waf1/Cip1/Sdi1) expression in response to ionizing radiation in a human osteosarcoma cell line, Saos-2",
abstract = "Purpose: The 123A point mutation of p53 showed increased radiosensitivity, whereas other mutations (143A, 175H, and 273H) were not affected. To determine the reason for increased radiosensitivity of the 123A mutation, the response of the transformant of 123A mutation to ionizing radiation (IR) was examined and compared to those of transformants with the wild type p53 or other point mutations (143A, 175H, and 273H).Methods and Materials: Stable transformants with a mutant or wild type p53 made by introducing cDNA into the human osteosarcoma cell line, Saos-2, which lacks an endogenous p53 were used. The transcriptional activity of mutant p53 was examined using a yeast functional assay. The transformants were examined for the accumulation of p53, the induction of p21(Waf1/Cip1/Sdi1) (hereafter referred to as p21), and the other response of p53-responsive genes (MDM2, Bax, and Bcl-2) by Western blotting. Apoptosis was analyzed by detection of DNA fragmentation.Results: The 123A point mutation of p53 was detected as a wild type in the yeast functional assay. The 123A mutant accumulated p53 in response to IR. The 123A mutant did not induce p21, but normally responded to MDM2, Bax, and Bcl-2. The 123A mutant entered apoptosis earlier than the wild type p53 transformant, and induced Fas at earlier in response to IR.Conclusion: The 123A mutant led to apoptosis, but not p21 expression in response to IR. The occurrence of apoptosis, but not induction of p21, corresponded to the radiosensitivity in the transformant. The early occurrence of apoptosis in 123A transformants may depend on the early induction of Fas. Copyright (C) 1999 Elsevier Science Inc.",
keywords = "Apoptosis, Ionizing radiation, Mutant p53, p21, Yeast functional assay",
author = "Kumio Okaichi and Wang, {Li Hong} and Sasaki, {Ji ichiro} and Hideyuki Saya and Mitsuhiro Tada and Yutaka Okumura",
year = "1999",
month = "11",
day = "1",
doi = "10.1016/S0360-3016(99)00285-0",
language = "English",
volume = "45",
pages = "975--980",
journal = "International Journal of Radiation Oncology Biology Physics",
issn = "0360-3016",
publisher = "Elsevier Inc.",
number = "4",

}

TY - JOUR

T1 - A point mutation of human p53, which was not detected as a mutation by a yeast functional assay, led to apoptosis but not p21(Waf1/Cip1/Sdi1) expression in response to ionizing radiation in a human osteosarcoma cell line, Saos-2

AU - Okaichi, Kumio

AU - Wang, Li Hong

AU - Sasaki, Ji ichiro

AU - Saya, Hideyuki

AU - Tada, Mitsuhiro

AU - Okumura, Yutaka

PY - 1999/11/1

Y1 - 1999/11/1

N2 - Purpose: The 123A point mutation of p53 showed increased radiosensitivity, whereas other mutations (143A, 175H, and 273H) were not affected. To determine the reason for increased radiosensitivity of the 123A mutation, the response of the transformant of 123A mutation to ionizing radiation (IR) was examined and compared to those of transformants with the wild type p53 or other point mutations (143A, 175H, and 273H).Methods and Materials: Stable transformants with a mutant or wild type p53 made by introducing cDNA into the human osteosarcoma cell line, Saos-2, which lacks an endogenous p53 were used. The transcriptional activity of mutant p53 was examined using a yeast functional assay. The transformants were examined for the accumulation of p53, the induction of p21(Waf1/Cip1/Sdi1) (hereafter referred to as p21), and the other response of p53-responsive genes (MDM2, Bax, and Bcl-2) by Western blotting. Apoptosis was analyzed by detection of DNA fragmentation.Results: The 123A point mutation of p53 was detected as a wild type in the yeast functional assay. The 123A mutant accumulated p53 in response to IR. The 123A mutant did not induce p21, but normally responded to MDM2, Bax, and Bcl-2. The 123A mutant entered apoptosis earlier than the wild type p53 transformant, and induced Fas at earlier in response to IR.Conclusion: The 123A mutant led to apoptosis, but not p21 expression in response to IR. The occurrence of apoptosis, but not induction of p21, corresponded to the radiosensitivity in the transformant. The early occurrence of apoptosis in 123A transformants may depend on the early induction of Fas. Copyright (C) 1999 Elsevier Science Inc.

AB - Purpose: The 123A point mutation of p53 showed increased radiosensitivity, whereas other mutations (143A, 175H, and 273H) were not affected. To determine the reason for increased radiosensitivity of the 123A mutation, the response of the transformant of 123A mutation to ionizing radiation (IR) was examined and compared to those of transformants with the wild type p53 or other point mutations (143A, 175H, and 273H).Methods and Materials: Stable transformants with a mutant or wild type p53 made by introducing cDNA into the human osteosarcoma cell line, Saos-2, which lacks an endogenous p53 were used. The transcriptional activity of mutant p53 was examined using a yeast functional assay. The transformants were examined for the accumulation of p53, the induction of p21(Waf1/Cip1/Sdi1) (hereafter referred to as p21), and the other response of p53-responsive genes (MDM2, Bax, and Bcl-2) by Western blotting. Apoptosis was analyzed by detection of DNA fragmentation.Results: The 123A point mutation of p53 was detected as a wild type in the yeast functional assay. The 123A mutant accumulated p53 in response to IR. The 123A mutant did not induce p21, but normally responded to MDM2, Bax, and Bcl-2. The 123A mutant entered apoptosis earlier than the wild type p53 transformant, and induced Fas at earlier in response to IR.Conclusion: The 123A mutant led to apoptosis, but not p21 expression in response to IR. The occurrence of apoptosis, but not induction of p21, corresponded to the radiosensitivity in the transformant. The early occurrence of apoptosis in 123A transformants may depend on the early induction of Fas. Copyright (C) 1999 Elsevier Science Inc.

KW - Apoptosis

KW - Ionizing radiation

KW - Mutant p53

KW - p21

KW - Yeast functional assay

UR - http://www.scopus.com/inward/record.url?scp=0032743254&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0032743254&partnerID=8YFLogxK

U2 - 10.1016/S0360-3016(99)00285-0

DO - 10.1016/S0360-3016(99)00285-0

M3 - Article

C2 - 10571205

AN - SCOPUS:0032743254

VL - 45

SP - 975

EP - 980

JO - International Journal of Radiation Oncology Biology Physics

JF - International Journal of Radiation Oncology Biology Physics

SN - 0360-3016

IS - 4

ER -