Cercosporin is produced by a plant pathogen, Cercosporakikuchii, and the elsinochromes, pigments of the elsinoe family of fungi. Cercosporin is a potent photosensitizer with a short activation wavelength, mostly suitable for superficial photodynamic therapy (PDT) treatments, especially when it is necessary to avoid perforations[1].Cercosporin contains the perylenequinone structural features necessary to PKC activity with an IC50 of 0.6-1.3 μM[2].
Cercosporin (0.8-8.0 μM; 30 s, 60 s, 90 s, 120 s) photodynamic therapy (PDT) effect is stronger in T98G cells than in U87 or MCF7 cells, the LD50 value for the T98G cells (0.14 J cm2) is much less than the LD50 value for MCF-7 and U87 cell lines (0.26 and 0.24 J cm2, respectively)[1].Cercosporin (0-3 μΜ; 24 hours) interplays with copper results in a synergistic cytotoxicity in MCF7 and T98G cells, that is, S(CuSO4 + Cerco) ≪ S(CuSO4) x S(Cerco), barely has an additive effect in U87 cells[1].
References:
[1]. Mastrangelopoulou M, et al. Cytotoxic and Photocytotoxic Effects of Cercosporin on Human Tumor Cell Lines. Photochem Photobiol. 2019 Jan;95(1):387-396.
[2]. Morgan BJ, et al. Design, synthesis, and investigation of protein kinase C inhibitors: total syntheses of (+)-calphostin D, (+)-phleichrome, cercosporin, and new photoactive perylenequinones. J Am Chem Soc. 2009 Jul 8;131(26):9413-25.