Hyperthermia Intensifies α-Mangostin and Synthetic Xanthones’ Antimalignancy Properties

In order to improve naturally occurring xanthones' anticancer properties, chemical synthesis is proposed. In this study, from eight novel xanthone derivatives coupled to morpholine or aminoalkyl morpholine, only the two most active ones were chosen. For additional enhancement of the anticancer activity of our tested compounds, we combined chemotherapy with hyperthermia in the range of 39-41 °C, from which the mild conditions of 39 °C were the most influencing. This approach had a profound impact on the anticancer properties of the tested compounds. TOV-21G and SC-OV-3 ovarian cell line motility and metastasis behavior were tested in native and hyperthermia conditions, indicating decreased wound healing properties and clonogenic activity. Similarly, the expression of genes involved in metastasis was hampered. The expression of heat shock proteins involved in cancer progression (Hsc70, HSP90A, and HSP90B) was significantly influenced by xanthone derivatives. Chemotherapy in mild hyperthermia conditions had also an impact on decreasing mitochondria potential, visualized with JC-1. Synthetic xanthone ring modifications may increase the anticancer activity of the obtained substances. Additional improvement of their activity can be achieved by applying mild hyperthermia conditions. Further development of a combined anticancer therapy approach may result in increasing currently known chemotherapeutics, resulting in a greater recovery rate and diminishment of the cytotoxicity of drugs.