Efficacy and Safety of Systemic and Locoregional Cisplatin Chronotherapy in Rats with Ovarian Carcinoma.

AIM: Alterations in circadian rhythms caused by tumor growth are thought to be clinically relevant as they affect the prognosis and treatment response. We aimed to evaluate the chronotherapeutic approach in rats with ovarian cancer receiving cisplatin intravenously (IV) or with hyperthermic intraperitoneal chemoperfusion (HIPEC) and to assess daily variations in tumor and intestinal epithelium proliferation. METHODS: In the pilot study, we used 12 intact rats and 12 rats with transplantable ovarian cancer, which were euthanized at ZT0 (08:00, lights on), ZT6, ZT12 and ZT18. In the main study, we used 45 rats with transplantable ovarian cancer. Animals were randomized into five groups: control, HIPEC with cisplatin at ZT0 (08:00), HIPEC with cisplatin at ZT12 (20:00), IV cisplatin at ZT0 and IV cisplatin at ZT12. We assessed the proliferation rate of tumor and small intestinal epithelium, apoptosis in small intestinal epithelium, and levels of γ-H2AX (DNA damage/repair marker) in kidneys and liver. Survival was calculated in each group. RESULTS: Ascitic ovarian cancer disrupted daily variations in intestinal epithelium proliferation and DNA damage/repair in rats. Ovarian carcinoma exhibited no daily variation in mitotic activity. In animals receiving IV cisplatin, massive cell damage in the renal medulla and cystic changes within renal tubules were observed, unlike in rats receiving HIPEC. Tumor mitotic activity was lower in morning-treated groups. The median survival of rats in the control group was 8.5 days (95% CI 6.0-22.0), in HIPEC at ZT0 40.5 days (95% CI 28.0-47.0, p<0.001) and in HIPEC at ZT12 32.0 days (95% CI 28.0-37.0, p<0.001). CONCLUSION: In a rat model, ovarian tumor growth disrupted daily variations in intestinal epithelium proliferation and caused genotoxic stress in tumor-free tissues. HIPEC with cisplatin at ZT0 had a better efficacy/toxicity profile than HIPEC with cisplatin at ZT12 and IV administration at both time points.

Modeling of Chemoperfusion vs. Intravenous Administration of Cisplatin in Wistar Rats: Adsorption and Tissue Distribution.

Hyperthermic intraperitoneal chemoperfusion (HIPEC) is an established form of locoregional chemotherapy of peritoneum tumors. However, its efficacy and safety status remain a controversy, partially, due to scarce data on pharmacokinetics and toxicity profile of drugs under HIPEC. In the current study, 24 female Wistar rats were randomly assigned to receive cisplatin as HIPEC (n = 12, 20 mg/kg) or intravenously (i.v., n = 9, 4 mg/kg). The subgroups of three animals were used for the initial, intermediate, and late phases of the pharmacokinetic assessment. The animals were sacrificed on days 1 and 5. Blood, liver, kidney, and ovaries were evaluated for platinum content. Histological and immunohistochemical evaluation was undertaken in the liver and kidney. A trend for higher blood plasma platinum levels was observed for HIPEC compared to i.v. Significantly lower (p < 0.001) relative platinum binding to the proteins was observed in HIPEC animals compared to the i.v. administration. A five-fold higher concentration of cisplatin in HIPEC resulted in a ca. 2.5-fold increase in total blood platinum and ca. two-fold increase in blood ultrafitrable platinum ("free" Pt). Immunohistochemistry revealed higher kidney and liver damage after i.v. administration of cisplatin compared to HIPEC, although a five-fold higher dose of cisplatin was applied in HIPEC. Together with relatively lower absorption to the systemic circulation in HIPEC, higher protein binding is probably the primary reason for lower observed toxicity in HIPEC animals.

Melatonin Administered before or after a Cytotoxic Drug Increases Mammary Cancer Stabilization Rates in HER2/Neu Mice.

INTRODUCTION: The effects of chemotherapy are known to depend on the time of administration. Circadian rhythms are disturbed in tumors and in tumor bearers. Agents involved in controlling the circadian rhythms (chronobiotics) potentially can modify the outcomes of chemotherapeutics administered at different times of the day. Pineal hormone melatonin (MT) is a prototypic chronobiotic. OBJECTIVE: The aim of the study was to investigate if MT can affect efficacy or toxicity of chemotherapy drugs administered at the extreme time points of the working day of hospital personnel. METHODS: Cyclophosphamide, adriamycin, and 5-fluorouracil (CAF) and adriamycin and docetaxel (AT) cytotoxic drug combinations were administered on day 0 at 11:00 a.m. or at 5:00 p.m. (UTC+03:00) to 6-month-old female HER2/neu transgenic FVB/N mice bearing mammary adenocarcinomas. Some mice were additionally provided with MT in drinking water (20 mg/L) at night 1 week before or 3 weeks after treatment or during both periods. Tumor node sizes, body weight, and blood cell counts were determined right before treatment and on days 2, 7, 14, and 21. RESULTS: Significant decrease in the mean tumor node volume was found by days 14 and 21 upon all CAF and AT treatment schedules, except in animals treated with AT at 5:00 p.m. without supplementation with MT. In the latter case, mean tumor node volume on day 21 was the same as in the control. Supplementation of AT administered at 5:00 p.m. with MT improved the tumor response. CAF and AT regimens supplemented with MT also augmented the number of tumor nodes that did not increase by more than 20% by day 21 as compared to CAF or AT alone, respectively. This effect was significant in groups treated with AT at 5:00 p.m. and consistent upon other schedules. On day 7, leukopenia and anemia were registered in groups treated with CAF regimen; however, blood cell counts normalized by day 14. Both CAF and AT were associated with drop in the body weight registered on day 7. Supplementation with MT did not affect changes of the body weight and blood counts. CONCLUSIONS: MT supplementation to cytotoxic drugs can improve antitumor response, especially if it is blunted because of an inappropriate time of administration.