Ovarian Cancer Cells in Ascites Form Aggregates That Display a Hybrid Epithelial-Mesenchymal Phenotype and Allows Survival and Proliferation of Metastasizing Cells

Peritoneal metastases are the leading cause of morbidity and mortality in ovarian cancer. Cancer cells float in peritoneal fluid, named ascites, together with a definitely higher number of non neo-neoplastic cells, as single cells or multicellular aggregates. The aim of this work is to uncover the features that make these aggregates the metastasizing units. Immunofluorescence revealed that aggregates are made almost exclusively of ovarian cancer cells expressing the specific nuclear PAX8 protein. The same cells expressed epithelial and mesenchymal markers, such as EPCAM and αSMA, respectively. Expression of fibronectin further supported a hybrid epithelia-mesenchymal phenotype, that is maintained when aggregates are cultivated and proliferate. Hematopoietic cells as well as macrophages are negligible in the aggregates, while abundant in the ascitic fluid confirming their prominent role in establishing an eco-system necessary for the survival of ovarian cancer cells. Using ovarian cancer cell lines, we show that cells forming 3D structures neo-expressed thoroughly fibronectin and αSMA. Functional assays showed that αSMA and fibronectin are necessary for the compaction and survival of 3D structures. Altogether these data show that metastasizing units display a hybrid phenotype that allows maintenance of the 3D structures and the plasticity necessary for implant and seeding into peritoneal lining.

Effect of the anticancer drug methotrexate on the ascites form of a teratocarcinoma and survival of mice

The dose-dependent effect of a methotrexate is established as on an ascite form of a teratocarcinoma CBA9H6, and mice-recipients, however various doses of the entered methotrexate (6; 4 and 2 mkg/g body weights of an animal), at repeated introduction at an interval of 48 and 24 hours, don't destroy all population of embrioid bodies. So, at 3-fold and even 10-fold daily injections in a dose of 2 mkg/g of body weight in an abdominal cavity of mice 1,6 ± 0,2% and 0,038 ± 0,01% embrioid bodies (ascite form of a teratocarcinoma ) remain, respectively, at survival of mice 93,0 ± 8,5% and 14,0 ± 3,0%. The morphological analysis of a mode of a differentiation of embrioid bodies retransplantated from experimental animals to intact has shown earlier that the methotrexate hasn't had effect on histoblastic potentialities of stem cells of a teratocarcinoma CBA9H6.

Antitumor activity of Ormustine against transplanted leukemia in mice

Objective: Evaluation of antitumor activity of a novel alkylnitrosoureas derivative Ormustine (an alkylnitrosocarbamoyl L-ornithine) in mouse lymphoid leukemia models. Materials and methods Antitumor activity of Ormustine has been evaluated in B6D2F1 mice with ascites form of leukemia (L1210, L1210/arenosa, L1210/citrullin and P388) and the solid (P388) form. In this study we used preparations from the alkylnitrosourea group: Ormustine, Aranoza and Lizomustine. Treatment of animals was started 24 hours after inoculation of leukemia intraperitoneally, and 48 hours after inoculation subcutaneous P388. Drugs in a wide range of doses were administrated once intravenously. The follow up period of the animals continued until their death. Criteria of antitumor effect were increasing life expectancy and cure. Evaluation criteria of antitumor effect was the increase in life of experimental mice compared to control ones. Results. Antitumor activity of a novel alkylnitrosoureas derivative, Ormustine has been studied in vivo on the growth of transplanted lymphoid leukemia, such as L1210 (ascites version) and P388 (ascites and solid tumor). Effective dose of single intravenous injection Ormustine against lymphoid leukemia L1210 and P388 was 125 mg/kg. The drug effectively inhibited growth of experimental leukemia. The significant part of the mice with limfoleukemia has been cured. We have also established the single intravenous therapeutic dose of Ormustine on L1210 and Р388 leukemia - 125mg/kg of body weight. Conclusion. The data obtained characterizes Ormustin as a promissing anticancer drug.