ODC inhibitors(Toronto General Hospital)

To study the influence of polyamine metabolism inhibitors on the growth, metastasis and ornithine decarboxylase (ODC) activity of Lewis lung carcinoma.

Experiments were performed on female mice C57Bl/6 with Lewis lung carcinoma. Nω-hydroxy-nor-arginine (nor-NOHA) and α-difluoromethylornithine (DFMO) were used as arginase and ODC inhibitors, correspondently. Inhibition of tumor growth was calculated by comparison of tumor volume in the treated and control groups. The average number of metastases per animal in the group and the average volume of pulmonary metastases per animal in the group have been determined. Determination of ODC - the key enzyme of the polyamine synthesis - in the samples of experimental tumors was performed by method of Luqman S.

Administration of DFMO or it's combination with nor-NOHA resulted in the decrease of tumor growth rate, number and volume of lung metastases and was accompanied with reduced ODC activity in tumor tissue.

Modifiers of polyamine metabolism may be considered as promising targeted cancer therapy.

Polyamines are key regulators in cell growth and differentiation. It has been shown that ornithine decarboxylase (Odc) was essential for post-implantation embryo development, and overexpression of spermidine/spermine N1-acetyltransferase will lead to ovarian hypofunction and hypoplastic uteri. However, the expression and function of polyamine-related genes in mouse uterus during early pregnancy are still unknown. In this study we investigated the expression, regulation, and function of polyamine-related genes in mouse uterus during the peri-implantation period. Odc expression was strongly detected at implantation sites and stimulated by estrogen treatment. The expression of Odc antizyme 1 and spermidine/spermine N1-acetyltransferase was also highly shown at implantation sites and regulated by Odc or polyamine level in uterine cells. Embryo implantation was significantly inhibited by α-difluoromethylornithine, an Odc inhibitor. Moreover, the reduction of Odc activity caused by α-difluoromethylornithine treatment was compensated by the up-regulation of S-adenosylmethionine decarboxylase gene expression. Collectively, our results indicated that the coordinated expression of uterine polyamine-related genes may be important for embryo implantation.