The impact of circadian rhythm disruption on oxaliplatin tolerability and pharmacokinetics in Cry1-/-Cry2-/- mice under constant darkness

Abstract

Circadian rhythms, the 24-h oscillations of biological activities guided by the molecular clock, play a pivotal role in regulating various physiological processes in organisms. The intricate relationship between the loss of circadian rhythm and its influence on the tolerability and pharmacokinetic properties of anticancer drugs is poorly understood. In our study, we investigated the effects of oxaliplatin, a commonly used anticancer drug, on Cry1^-/- and Cry2^-/- mice (Cry DKO mice) under darkness conditions, where they exhibit free-running phenotype. We administered oxaliplatin at a dosage of 12 mg/kg/day at two distinct circadian times, CT8 and CT16, under constant darkness conditions to Cry DKO mice and their wild type littermates. Our results revealed a striking disparity in oxaliplatin tolerance between Cry DKO mice and their wild-type counterparts. Oxaliplatin exhibited severe toxicity in Cry DKO mice at both CT8 and CT16, in contrast to the wild type mice. Pharmacokinetic analyses suggested that such toxicity was a result of high concentrations of oxaliplatin in the serum and liver of Cry DKO mice after repeated dose injections. To understand the molecular basis of such intolerance, we performed RNA-seq studies using mouse livers. Our findings from the RNA-seq analysis highlighted the substantial impact of circadian rhythm disruption on gene expression, particularly affecting genes involved in detoxification and xenobiotic metabolism, such as the Gstm gene family. This dysregulation in detoxification pathways in Cry DKO mice likely contributes to the increased toxicity of oxaliplatin. In conclusion, our study highlights the crucial role of an intact molecular clock in dictating the tolerability of oxaliplatin. These findings emphasize the necessity of considering circadian rhythms in the administration of anticancer drugs, providing valuable insights into optimizing treatment strategies for cancer patients.

Keywords: Chronopharmacokinetics; Chronotoxicity; Circadian clock; Cryptochrome double-knockout mice; Oxaliplatin.

Fig. 1

Toxicology and pharmacokinetic profile of oxaliplatin in animals. % Body weight change following single dose (A) or repeated dose (B) injection of oxaliplatin (12 mg/kg/day) to the Cry DKO and wild type mice at CT8 and CT16. The results are presented as mean ± SEM (n = 3–4) (t-test; *p < 0.05; **p < 0.01). Plasma and liver pharmacokinetics of oxaliplatin following 12 mg/kg single dose injection to the Cry DKO and wild type mice at CT8 and CT16. (C) Plasma concentration–time curve. (D) Liver concentration–time curve. (E) Plasma AUC_0–∞ values. (F) Liver AUC_0–∞ values. The results are presented as mean ± SEM (n = 3–4) (Student’s t-test; *p < 0.05; **p < 0.01)

Fig. 2

Plasma and liver concentrations of oxaliplatin at 24 h following 12 mg/kg single dose injection (A) and three repeated doses (B). Results are presented as mean ± SEM (n = 5) (Student’s t-test; *p < 0.05; **p < 0.01, ***p < 0.001) (n = 3–4)

Fig. 3

Analysis of RNA-Seq data from Cry double knockout and their wildtype littermate. A The number of DEGs obtained after the comparison of different genetic background mice (WT or Cry KO) at different time points (CT8 or CT16). B Fold change of core clock genes obtained from the DEG analysis between WT mice at CT16 vs CT8. C Fold change of Gst genes obtained from the DEG analysis between WT vs Cry DKO mice at CT16; WT vs Cry DKO mice at CT8; and WT mice at CT16 vs CT8