Radiotherapy is one of the major therapies for cancer treatment. p53 acts as a central mediator of the cellular response to stressful stimuli, such as radiation. Recently it has been known that activation of the phosphatidylinositol- 3-kinase (PI3K) pathway is associated with radioresistance. In this study, we investigated whether X-irradiation up-regulates PI3K in a p53-dependent manner in human colon cancer cells. In order to study this phenomenon, we have treated p53-wild type and p53-mutant type HCT116 cells with X-ray. Treatment of wild type HCT116 cells with 8 Gy resulted in a marked increase in PI3K (p85), which paralleled an increase in PTEN, a counterpart of PI3K. However, these effects of X-rays in the p53-mutant cells were not observed. These results suggest that the X-irradiation- induced up-regulation of PI3K/PTEN pathway is p53-dependent.

ABSTRACT
 재료 및 방법
  재료
  세포 수확 과 X-ray 방사선조사
  Western blot 분석
  세포 생존력 결정
  데이타 분석
 결 과
  대장암세포에서 X-ray의 조사에 의한 p53 활성화
  대장암세포에서 p53이 세포내 PI3-K 및 PTEN의 기저농도에미치는 영향
  대장암세포에서 X-ray에 의하여 유도되는 PI3-K 및 PTEN의신호전달에 활성화에 미치는 p53의 영향
 고 찰
 참고문헌

• 이희관(예수병원 방사선 종양학과) | Heui Kwan Lee (Department of Radiation Oncology, Presbyterian Medical Center)
• 김종석(전북대학교 의학전문대학원 생화학 교실) | Jong Suk Kim (Department of Biochemistry, Chonbuk National University Medical School)
• 권형철(전북대학교병원 방사선 종양학과 및 임상의학연구소) | Hyoung Cheol Kwon (Department of Radiation Oncology & Research Institute of Clinical Medicine, Chonbuk National University Hospital) Correspondence to