Adaptive response is differently induced depending on the sensitivity to radiation-induced cell death in mouse epidermal cells.
We investigated the relationship between induction of radio-adaptive response and cell death in mouse normal and neoplastic epidermal cells. Mouse normal primary keratinocytes (PK), cancer-prone cells [v-rasHa-transfected mouse keratinocytes (ras-PK), and line 308 cells (mouse skin papilloma cells which have activated rasHa gene with A-to-T transversion at codon 61) were primed with a low dose of gamma-rays (0.01 Gy), and were challenged with a high dose (4 Gy) after a 4 or 7 h interval. The induction of cell death in PK was 2-10 times higher and was also more rapid in PK than in ras-PK or 308 cells. Low-dose pretreatment with a 4 h interval decreased cell death, and this adaptive response was prominent in PK, whereas it was less obvious in the cases of ras-PK and 308 cells. The response of each protein kinase C (PKC) isozymes to high-dose radiation, especially PKCalpha, PKCdelta, PKCepsilon, and PKCeta, were different between the normal and ras oncogene-activated neoplastic keratinocytes; translocation of these isozymes to membrane occurred more rapidly in normal than in neoplastic cells. Furthermore, low-dose pretreatment did not induce the translocation of PKCdelta in PK significantly more than in ras-PK and 308. Thus, the difference in the induction of radio-adaptive responses between mouse normal and neoplastic epidermal cells reflects difference in the rapidity of cell death, and responsiveness of PKC may affect this adaptive response.
Lee
S J
SJ
Laboratory of Radiation Effect, Korea Cancer Center Hospital, Seoul.
Choi
S A
SA
Cho
C K
CK
Kim
T H
TH
Jeong
K S
KS
Yoo
S Y
SY
Lee
Y S
YS
D000222:Adaptation, Physiological / Q000528:radiation effects; D000818:Animals; D017209:Apoptosis / Q000528:radiation effects*; D002461:Cell Line, Transformed; D003600:Cytosol / Q000201:enzymology; D000078404:Epidermal Cells; D004817:Epidermis / Q000528:radiation effects*; D020287:In Situ Nick-End Labeling; D007527:Isoenzymes / Q000378:metabolism; D015603:Keratinocytes / Q000166:cytology* / Q000201:enzymology / Q000528:radiation effects*; D051379:Mice; D008807:Mice, Inbred BALB C; D010212:Papilloma; D011493:Protein Kinase C / Q000378:metabolism; D051571:Protein Kinase C-alpha; D011829:Radiation Dosage; D011832:Radiation Injuries / Q000378:metabolism; D012878:Skin Neoplasms; D014407:Tumor Cells, Cultured; D018631:ras Proteins / Q000378:metabolism
D007527:Isoenzymes; C496630:Prkca protein, mouse; D011493:Protein Kinase C; D051571:Protein Kinase C-alpha; D018631:ras Proteins