Plant Flavonoids: a Group of Compounds with Antineoplastic Activity on B16-F10 Murine Melanoma Cells

Berries are well known for containing flavonoids including anthocyanins (ACN), that may have positive effects on human health. The antiproliferative activity and differentiation potential of ANC-rich extracts from strawberry fruit (SFE) were investigated on highly metastatic murine melanoma B16-F10 cell line. Cell treatment with SFE produced a remarkable reduction of cell proliferation and of intracellular levels of polyamines, and the enhancement of tissue transglutaminase (TG2) activity (used as a differentiation marker). Altered protein expression profiles were detected in treated cells by proteomic analysis. In particular, proteins overexpressed in cancer cells, involved in tumor progression and metabolism, were down-regulated. Besides fruits, another potential source of flavonoids is represented by plant cell cultures, because of the continuous production and chance to elicit the synthesis. Strawberry (SC), blackberry (BC), red raspberry (RRC) and strawberry-tree (STC) cell suspensions were elicited in order to determine the possibility to enhance the production and the antiproliferative activity of the extracts. Various elicitor treatments were chosen, i.e. changes of temperature, type of light, and different nitrogen content of the growth medium. The ANC extracts from all tested species reduced cell proliferation of melanoma. An improvement of antiproliferative activity on murine melanoma cells, respect to the un-elicited suspensions, was shown by the extracts from SC and STC cells treated with red and blue light and BC with blue light. In STC a high correlation between ANC content of the extracts and effectiveness in reducing cell proliferation was detected.