Circadian variations in cell cycle phase distribution in a squamous cell carcinoma xenograft; effects of cisplatin and fluorouracil treatment.
Tumor tissue sampled at different points during a 24 hour period (08-08) from a xenografted squamous cell carcinoma of the head and neck was analyzed with flow cytometry. Statistically significant variations were found in the mean fraction of cells in the G1, S and G2 phases, the most pronounced variation occurring at 14 and 02 h. Histopathological examination showed no consistent circadian fluctuations in the fraction of cells in mitosis. Treatment with NaCl, cisplatin and fluorouracil was given at the time of most pronounced variation (i.e., 14 and 02 h). Toxicity was low. All animals in all groups survived treatment. All treated animals lost weight, but the initial weight loss was slightly greater and recovery delayed in the groups given cisplatin and fluorouracil at night. Tumor growth inhibition, as defined by the area under the growth curve, did not differ significantly between 14 and 02 h.
Rydell
R
R
Department of Oto-rhino-laryngology, University Hospital, Lund, Sweden.
Wennerberg
J
J
Willen
R
R
D000818:Animals; D002294:Carcinoma, Squamous Cell / Q000188:drug therapy / Q000473:pathology*; D002453:Cell Cycle / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D002460:Cell Line; D002940:Circadian Rhythm / Q000187:drug effects; D002945:Cisplatin / Q000494:pharmacology / Q000627:therapeutic use*; D005260:Female; D005472:Fluorouracil / Q000494:pharmacology / Q000627:therapeutic use*; D006801:Humans; D008297:Male; D051379:Mice; D008819:Mice, Nude; D009368:Neoplasm Transplantation; D009669:Nose Neoplasms / Q000188:drug therapy / Q000473:pathology; D014183:Transplantation, Heterologous
D002945:Cisplatin; D005472:Fluorouracil