Endocrine Abstracts

Ouabain is a cardiotonic steroid belonging to Strophanthus species. Recently its role in the treatment of tumors has been investigated, as ouabain seems to exert antiproliferative effects. Adrenocortical carcinoma (ACC) is a rare cancer, with poor prognosis, of which SW13 and H295R cells could be considered a cellular model.

Our aim was to evaluate if ouabain exerts anticancer property.

The effects of ouabain were assessed by MTT assay, by [3H] thymidine assay, by Wright’s staining method, by flow cytometry analysis, by homogeneous caspase assay and by western blot.

Ouabain induced a reduction in cell viability at 24h and 72h in SW13, in H295R and 4 primary adrenocortical tumor cells. Proliferation rate decreased effectively in SW13 and H295R at higher doses. Marked morphological changes were observed both for SW13 and H295R, with an increase in necrotic process. Cell cycle distribution was altered by ouabain in SW13. Apoptosis analysis demonstrated an increase in caspase activity, clearly evident for SW13 at 72h. FACS analysis by Annexin V-FITC and propidium iodide confirmed an increase in necrotic process especially at higher concentrations. Western blot analysis showed Erk, Akt, p-Akt, P70s6k and p-P70s6k decreased in the treatments of SW13.

Our study demonstrated the antiproliferative effects of ouabain on SW13 and H295R cell models and on primary adrenocortical tumor cells. The results we obtained are promising, but more data are needed to better clarify the role of ouabain in these cellular models, before attempting any approach to animal models.

Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.

Funding: This work was supported, however funding details unavailable.