Preferential cytoplasmic localization of p34cdc2 in recurrent human squamous cell carcinoma after radiotherapy.
Duration of the G2-phase delay and arrest after exposure to ionizing radiation is thought to influence radiosensitivity. The kinase activity of the p34cdc2-cyclin B complex and the p34cdc2-cyclin A complex is implicated in G2- to M-phase transition and in G2-phase arrest after exposure to ionizing radiation. We analyzed the expression level and the subcellular location of p34cdc2, cyclin A and cyclin B in head and neck squamous cell carcinoma (SCC) tumors; samples were obtained from patients with locally nonrecurrent and recurrent tumors that had been treated by surgery and radiotherapy. No significant difference was noticed in cyclin A, cyclin B and p34cdc2 expression. However, we noted a significant preferential cytoplasmic location of p34cdc2 in recurring tumors compared to the nonrecurring ones (P < 0.001). This abnormal location of p34cdc2 occurs even in primary tumors in patients with recurring tumors, suggesting that a default in the activation of p34cdc2 kinase could be implicated in clinical radioresistance.
Cohen-Jonathan
E
E
Department of Radiotherapy, Paul Sabatier University and INSERM U397, Toulouse, France.
Toulas
C
C
Rochaix
P
P
Bachaud
J M
JM
Daly-Schveitzer
N
N
Favre
G
G
D016203:CDC2 Protein Kinase / Q000378:metabolism*; D002294:Carcinoma, Squamous Cell / Q000378:metabolism* / Q000532:radiotherapy / Q000648:ultrastructure; D016213:Cyclins / Q000378:metabolism; D003593:Cytoplasm / Q000378:metabolism*; D006258:Head and Neck Neoplasms / Q000378:metabolism* / Q000532:radiotherapy / Q000648:ultrastructure; D006801:Humans; D007124:Immunoenzyme Techniques; D009364:Neoplasm Recurrence, Local / Q000378:metabolism / Q000648:ultrastructure
D016213:Cyclins; D016203:CDC2 Protein Kinase