Circadian telomerase activity and DNA synthesis for timing peptide administration.
DNA synthesis and telomerase activity were assessed in nude mice transplanted with hepatic carcinoma. Hepatic cancer cells (SMMC-7721) were implanted into both flanks of each of 14 BALB/C mice synchronized in 12 h of light alternating with 12 h of darkness (LD12:12) for 4 weeks. At 7 timepoints, tumor samples were collected for measurement of cellular DNA content by flow cytometry and telomerase activity by PCR-ELISA assay. Cosinor analyses determine a 24-h rhythm for all variables, showing a similar timing for the DNA-synthesis phase and telomerase activity. These results provide a model for exploring optimal timing of chronotherapy with peptides, especially for treatment with telomerase inhibitors.
Medical Center, Sichuan University, Sichuan, PR China.
Yi
Y
Qu
Zhengrong
Z
Wang
Xiang
X
Huang
Chaomin
C
Wan
Chun-lei
CL
Yang
Bailin
B
Liu
Germaine
G
Cornelissen
Franz
F
Halberg
D000818:Animals; D045744:Cell Line, Tumor; D002940:Circadian Rhythm; D004247:DNA / Q000032:analysis / Q000096:biosynthesis; D004261:DNA Replication; D003624:Darkness; D008027:Light; D008113:Liver Neoplasms / Q000201:enzymology / Q000235:genetics / Q000473:pathology; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D009368:Neoplasm Transplantation; D010455:Peptides / Q000008:administration & dosage* / Q000494:pharmacology; D019098:Telomerase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D013997:Time Factors
D010455:Peptides; D004247:DNA; D019098:Telomerase