The Diatom <i>Cylindrotheca closterium</i> and the Chlorophyll Breakdown Product Pheophorbide <i>a</i> for Photodynamic Therapy Applications

Abstract

Microalgae, eukaryotic unicellular plants that are distributed worldwide, have been shown to exert anti-proliferative and anticancer activities on various human cancer cell lines. An example of a microalgal bioactive compound is a chlorophyll breakdown product named Pheophorbide a (Ppa), which has been reported to have anti-proliferative properties against various cell lines. This compound has also been tested with light exposure in photodynamic therapy for cancer treatment. In this paper, we screened eleven marine microalgae against a panel of cancer cells, and evaluated the synergistic anti-proliferative effect with Pheophorbide a, with and without photo-activation. The results showed significant anti-proliferative activity against melanoma cells when Ppa was combined with fraction E of the diatom Cylindrotheca closterium plus 1 h photo-activation. Its activity was also analyzed using gene expression and Western blot experiments. Altogether, these data give new insights into the possible application of microalgae for photodynamic therapy.

Keywords

• microalgae
• <i>Cylindrotheca closterium</i>
• Pheophorbide <i>a</i>
• photodynamic therapy
• cancer
• biotechnological applications