Spectral Properties and Anticancer Activity of Novel Cisplatin-BODIPY Conjugates

Two novel cisplatin – boron-dipyrromethene (BODIPY) conjugates – cisPt-pP-BODIPY and cis-Pt-oP-BODIPY differing in the position of attachment of platinum-containing component – were synthesized. Their structural peculiarities determined, on the one hand, bathochromic shifts of absorption and fluorescence bands and a pronounced decrease in molar absorption coefficients and fluorescence quantum yields as compared to the initial BODIPYs, and, on the other hand, the ability to generate singlet oxygen in solutions. Cisplatin-BODIPY conjugates demonstrated a potent cytotoxic activity against a broad spectrum of cancer cell lines, including those that exhibited multidrug resistance to certain chemotherapeutic agents, including doxorubicin and paclitaxel. Important, the cytotoxic activity of the conjugates was increased after the light exposure, thereby illustrating their potential use for photodynamic therapy. Lastly, a conjugation of cisplatin with BODIPYs allowed us to assess the intracellular accumulation of cisplatin in cancer cells and further examined more precisely the molecular mechanisms of its efflux from cancer cells via ABCB1- and ABCG2-mediated mechanisms.