Relationship between Radiosensitivity and Repair Capacity in Human Epithelial Cancer Cell Lines.
- Author:
Sung Whan HA
1
;
Charn Il PARK
;
Kyoung Hwan KOH
Author Information
1. Department of Therapeutic Radiology, College of Medicine, seoul National University, Seoul, Korea.
- Publication Type:Original Article
- MeSH:
Cell Line*;
Humans*;
Radiation Tolerance*
- From:Journal of the Korean Society for Therapeutic Radiology
1993;11(1):17-28
- CountryRepublic of Korea
- Language:Korean
-
Abstract:
To investigate the relationship between Radiosensitivity and postirradiation recovery in human cancer cells, a study was performed using human cancer cell lines-A549, CaSki, SNU-C5 and PCI-13. for the study of radiosensitivity, single doses of 2, 4, 6, 8, 10, 12, and 14 Gy were given and for postirradiation recovery, two fractions of 4 Gy were separated with a time interval of 0, 0.5, 1,1.5, 2, 2.5, 3, 4, 5, or 6 hours. Surviving fraction was estimated using colony forming ability. Surviving fractions at 2 Gy (SF2) were 0.496 (0.570-0.412) for A549, 0.496 (0.660-0.332) for CaSki, 0.386 (0.576-0.216) for SNU-C5, and 0.185(0.247-0.123) for PCI-13. By statistical analysis the SF2 of PCI-13 was lower significantly than those of others (p<0.05). this difference was also observed at 4,6 and 8 Gy dose levels. At 6 and 8 Gy the surviving fractions of SMU-C5 were also lower significantly than A549 and CaSki(p<0.05). By the analysis with linear quadratic model, the value of alpha for A549, CaSki, SNU-C5 and PCI-13 were 0.3016, 0.3212, 0.4327 and 0.8423, respectively, and those of betawere 0.024929, 0.02009, 0.03349 and 0.00059, respectively. So, the value of alpha showed increasing tendency with decreasing SF2.By the multitarget single hit model the values of Do for A549, CaSki, SUN-C5 and PCI-13 were 1.97, 1.97,1.46 and 0.81, respectively, and those of n were 1.53, 1.50, 1.56 and 2.28, respectively. So, the value of Do decreased with decreasing SF2. Post-irradiation recovery reached plateau at around 2 hours. Recovery ratio at plateau phase ranged from 1.2 to 4.2; the value were 1.2 for PCI-13, 3.2 for CaSki, 3.3 for SNU-C5, and 4.2 for A549. Recovery rate well correlated with SF2, and increased with increasing Do and decreasing alpha. According to above results, the intrinsic radiosensitivity was quite different among the tested cell ilnes; PCI-13 was the most sensitive and A549 and CaSki was similar. This difference of radiosensitivity is thought to be partly due to the difference in amount of postirradiation recovery. By linear quadratic model the difference of alpha values was very high, and by multitarget single hit model the difference of Do value was significantly high among four cell lines.
