Circadian rhythms and tumor development are interconnected as the factors like light pollution which disrupt circadian rhythms increase the risk of cancer, and oncological diseases are associated with changes in organism’s circadian rhythms. Circadian changes in intestinal epithelium and mammary tumors proliferation and apoptosis in HER-2/neu overexpressing FVB/N mice and assessment of melatonin’s influence on these parameters were studied in this work. It was shown by us that intestinal epithelium in mice exhibits circadian rhythm of proliferation with the peak in the morning and in tumor-bearing mice this rhythm is disrupted. Exogenous melatonin contributes to circadian rhythm of intestinal epithelium proliferation. Circadian changes in mammary tumors proliferation rate depend on melatonin secretion or supplementation time. Thus, melatonin may be considered as a perspective drug in anticancer therapy modulating circadian rhythms in cancerous and normal tissues.
The antitumor activity of the antifibrinolytic drug ε-aminocaproic acid (ACC) in the therapeutic form (5% ACC solution in physiological solution instead of drinking water) was studied in the ascitic and solid Ehrlich tumor. ACC did not affect the growth of ascitic, as well as a solid Ehrlich tumor, when the drug was administered 72 hours after the tumor inoculation. At the same time, when it was administered 7 days after tumor inoculation, the drug had a statistically significant antitumor effect on the tumor nodes formed (8-10 mm in diameter). ACC antitumor effect allows to assume that it influences tumor stroma rather than the parenchyma. This effect is not fully understood and needs further study.
Possibilities of the liver tumor modeling were assessed in rabbits of Soviet Chinchilla strain by implantation into the left lobe of the liver slices of squamous cell VX2 tumor obtained from donor rabbits inoculated with the tumor in the thigh muscles. The basic parameters of the model were established - the dynamics of tumor growth, inoculation rate, incidence of concomitant abdominal tumors. There was offered a method for minimally invasive monitoring of the development of the tumor after implantation to the liver by means of the level of venous blood granulocytes. It was found that the most appropriate way to diagnose liver tumors in rabbits was computed tomography scan.
The study aimed to assess combined treatment with mTOR inhibitor rapamycin and cytotoxic drugs (doxorubicin and paclitaxel) on two models of transplantable tumors - mammary adenocarcinoma in male HER-2/neu transgenic FVB/N mice and solid Ehrlich carcinoma in male 129/Sv mice. Rapamycin (total dose of 3.6 mg kg), doxorubicin (total dose of 15 mg/ kg), paclitaxel (total dose of 6 mg/kg) or their combination were intraperitoneally injected to mice with developed tumor node. Rapamycin showed its own antitumor activity by tumor growth inhibition up to 42% in mammary adenocarcinoma model and up to 57% in Ehrlich carcinoma model. A tendency to an increase in the antitumor activity of chemotherapeutic drugs with the addition of rapamycin was revealed. The cyto-protective effect of the mTOR inhibitor was observed during therapy with doxorubicin and paclitaxel, expressed in a significant decrease in the level of apoptosis in normal epithelium of jejunum crypts. Thus, revealed protective effect of mTOR inhibitor on jejunum epithelium could be applied for reduction of chemotherapeutic drugs enterotoxic effect without any efficiency reduction. Thus, in perspective that could expand the possibilities of standard chemotherapeutic treatment and improve the quality of life of cancer patients.
Introduction. Non-steroidal anti-inflammatory drugs and, in particular, diclofenac, are considered as drugs with a potentially anticarcinogenic effect and can be used to enhance the effects of antitumor therapy. Aim. To evaluate the effectiveness of diclofenac as a potential modifier of photodynamic therapy (PDT) in vivo in Ehrlich tumor model in mice. Materials and methods. The study was conducted on male mice of BALB/C strain with intradermally grafted Ehrlich carcinoma. Experimental procedures were performed on day 7 after tumor inoculation. The control group did not receive treatment, in one group only diclofenac was administered, photosensitizer was administered in three groups (photoditazin, 5 mg / kg, intravenously once), tumor was irradiated with a laser (ALOD, 662 nm) or PDT was performed, respectively, and in three groups the procedures indicated above in each case were combined with the administration of diclofenac. 2 series of experiments were conducted to assess the reproducibility of the results. The size of the tumor was recorded after exposure. Results. In the first series of the experiment, in all groups with the administration of diclofenac (45 mg/kg/day), a high animal mortality was unexpectedly observed, associated with the toxic effect of diclofenac, which required a change in its administration regime and dose (15 mg/kg) in the second series of the experiment. The administration of diclofenac did not significantly affect the efficacy of PDT, and also did not have a modifying effect in other groups (with the introduction of a photosensitizer or laser irradiation) compared with similar groups without diclofenac. PDT with photoditazine turned out to be the most effective treatment regimen: in 8 out of 10 mice in the group from the 21th day after procedure the tumors were not recorded, the animals were alive until the end of the observation for 60 days. The introduction of a photosensitizer and radiation without a photosensitizer did not lead to a significant inhibition of tumor growth. Conclusion. In vivo on a model of intradermally grafted Ehrlich tumor in mice, diclofenac does not have a modifying effect on the antitumor effects of PDT.
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