Protein expression following gamma-irradiation relevant to growth arrest and apoptosis in colon cancer cells.
OBJECTIVE
To study expression of proteins previously connected to radiotherapy response in rectal cancer patients, namely, p53, TAp73, DeltaNp73, survivin and PRL-3, after irradiation in colon cancer cells to gain standing ground for further studies of pathways and mechanisms.


METHODS
Three colon cancer cell lines (KM12C, KM12SM and KM12L4a) with one origin were radiated with gamma-radiation. Radiosensitivity was determined with cell cycle, survival fraction at 5 Gy (SF5) and apoptosis analysis and protein expression by Western blot.


RESULTS
Following irradiation, KM12C showed no cell cycle arrest, and low SF5 and apoptosis, whilst KM12L4a showed high SF5 and apoptosis. KM12SM had moderate radiosensitivity. After irradiation, the anti-apoptotic DeltaNp73 and mitosis-factor PRL-3 increased in KM12C and the radioresistance factor survivin increased in KM12L4a.


CONCLUSIONS
The cell lines seem to have evolved different protein patterns regarding the studied proteins and partly therefore developed different resistance mechanisms, less apoptosis for KM12C and continued proliferation for KM12L4a, after gamma-irradiation.
Pfeifer
Daniella
D
Division of Oncology, Department of Clinical and Experimental Medicine, University Hospital, Linköping University, 581 85 Linköping, Sweden. daniella.pfeifer@liu.se
Wallin
Asa
A
Holmlund
Birgitta
B
Sun
Xiao-Feng
XF
D017209:Apoptosis / Q000528:radiation effects*; D002453:Cell Cycle / Q000528:radiation effects; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000528:radiation effects; D002470:Cell Survival / Q000528:radiation effects; D003110:Colonic Neoplasms / Q000737:chemistry / Q000473:pathology / Q000532:radiotherapy*; D004268:DNA-Binding Proteins / Q000032:analysis / Q000502:physiology; D005720:Gamma Rays; D006801:Humans; D051034:Inhibitor of Apoptosis Proteins; D008869:Microtubule-Associated Proteins / Q000032:analysis; D009363:Neoplasm Proteins / Q000032:analysis / Q000502:physiology; D009687:Nuclear Proteins / Q000032:analysis / Q000502:physiology; D017027:Protein Tyrosine Phosphatases / Q000032:analysis / Q000502:physiology; D000077022:Survivin; D000072160:Tumor Protein p73; D016159:Tumor Suppressor Protein p53 / Q000032:analysis / Q000502:physiology; D025521:Tumor Suppressor Proteins / Q000032:analysis / Q000502:physiology
C107489:BIRC5 protein, human; D004268:DNA-Binding Proteins; D051034:Inhibitor of Apoptosis Proteins; D008869:Microtubule-Associated Proteins; D009363:Neoplasm Proteins; D009687:Nuclear Proteins; D000077022:Survivin; D000072160:Tumor Protein p73; D016159:Tumor Suppressor Protein p53; D025521:Tumor Suppressor Proteins; C000606369:delta Np73 protein, human; C484730:PTP4A3 protein, human; D017027:Protein Tyrosine Phosphatases