Exploring the Cellular Interactions of Flavonoids with Similar Structures in Cells Overexpressing the 70 kDa Human Heat Shock Protein

Abstract

Flavonoids share a common structural framework that serves as a hallmark indicative of their biological activity. In this study, we investigated the effects of two structurally similar flavonoids, fisetin and morin, through independent and combined in vitro assessments on embryonic mouse cells overexpressing the human 70 kDa heat shock protein (Hsp70) (Tg/Tg) and normal mouse fibroblast cell line (NIH/3T3). The primary objectives were to evaluate the biocompatibility and potential cytotoxicity of these flavonoids, along with assessing the cytoprotective role of Hsp70 in these cellular environments. To address these objectives, we conducted dose- and time-dependent cell survival tests. Additionally, we utilized flow cytometry to detect intracellular reactive oxygen species (ROS) production and to analyze apoptosis and the cell cycle. Throughout the experimental procedures, a notable observation was made: NIH/3T3 normal cells exhibited greater susceptibility compared to Tg/Tg cells when exposed to fisetin and morin. This difference in susceptibility is likely attributed to the robust cytoprotective effect of Hsp70 in Tg/Tg cells. Importantly, both cell lines demonstrated increased sensitivity to fisetin toxicity in comparison to morin, leading to significantly lower cell survival rates. These findings shed light on the differential responses of cell lines to flavonoid exposure, emphasizing the influence of Hsp70 and the distinct impact of fisetin and morin on cell viability.