Effects of Teucrium polium L. and Teucrium montanum L.: Extracts on mechanisms of apoptosis in breast and colon cancer cells

Abstract

The aim of this study was to determine the cytotoxic and proapoptotic activity of methanol extracts from Teucrium polium L. and T. montanum L. on immortalized cell lines of breast cancer (MDA-MB-231) and colorectal carcinoma (SW480). The cytotoxic activity was determined using MTT cell viability assay, where IC50 value was used as a parameter for cytotoxicity. The type of cell death was explored by fluorescence microscopy using acridine orange/ethidium bromide method. For determination apoptosis signal pathways expression of Fas receptor was monitored by immunofluorescence, while caspases 8 and 9 activity was analyzed, by colorimetric based assays. The results indicate that both plant extracts induced decrease of MDA-MB-231 and SW-480 cell viability, good cytotoxicity (IC50 values in range of 118.26 to 429.32 µg/ml, depends on type of cells and extracts, as well on treatment periods) and induced apoptosis, as a dominant type of cells death (6-11% of total cells). Investigated treatments led to increase in Fas receptor expression only in the case of T. montanum treatment on MDA-MB-231 cells. Additionaly, apoptosis was activated and realized via external pathway with the activation of internal apoptotic pathway mediated by caspases 8 i 9 in MDA-MB-231 cells while apoptosis occurred by caspase-independent pathway in SW480 cells. In conclusion, the results showed that the investigated methanol extract of Teucrium species showed good cytotoxic and proapoptotic activities, T. montanum expressed better activity, and the MDA-MB-231 cells were more sensitive to treatments.