Activation of Apoptosis and Autophagy by Gratiola Officinalis Extract in Human Tumor Cell Lines

Abstract

The problem of creating antitumor drugs with new mechanisms of action that predominantly induce apoptosis is still topical. The extract of Gratiola officinalis is a potential antitumor agent containing mainly flavonoids. The aim of this research is to study the effects of Gratiola officinalis extract on activation of apoptosis and autophagy in breast adenocarcinoma SK-BR-3 and kidney carcinoma A-498 lines. Apoptotic activity of the extract was studied by flow cytofluorometry using Hoechst stain and double staining with annexin V plus propidium iodide. There was 96.3% of cells in SK-BR-3 culture in late apoptosis phase detected by flow cytofluorometry method at the extract concentration of 0.88 mg/ml, 86.3% of cells were in apoptosis by Hoechst stain. The concentration of 0.82 mg/ml caused apoptosis in half of the cells. The extract has cytoprotective activity at low concentration (0.0352 mg/ml). The cytoprotection mechanism is realized through the activation of autophagy. The maximum number of autophagosomes in kidney carcinoma cells is observed at the extract concentration of 0.056 mg/ml. Thus, Gratiola officinalis extract is able to block cytoprotective autophagy with increasing the extract concentration and to activate apoptosis in 85% of tumor cells. Detailed research should be continued to understand the mechanisms of antitumor activity of Gratiola officinalis extract.