Photodynamic therapy of tumour cells mediated by the natural anthraquinone parietin and blue light

MUGAS ML ; CALVO G ; MARIONI J ; CÉSPEDES M ; MARTINEZ F; SÁENZ D; DI VENOSA G; CABRERA JL; NUÑEZ MONTOYA S; CASAS A

JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY

ELSEVIER SCIENCE SA

Lugar: Amsterdam; Año: 2020

1011-1344

Photodynamic therapy (PDT) is a treatment for superficial tumours involving theadministration of a photosensitiser followed by irradiation.The potential of the natural anthraquinone parietin (PTN) in PDT is still relativelyunexploited. In the present work, PTN isolated from the lichen Teoloschistes nodulifer(Nyl.) Hillman (Telochistaceae) was evaluated as a potential photosensitiser on tumourcells employing UVA-Vis and blue light.Blue light of 2 J/cm2 was capable of inducing 50% of death in K562 leukaemic cells treated1 h with 30 µM PTN (Protocol a). Higher light doses (8 J/cm2) are required to achieve thesame percentage of cell death employing lower PTN concentration (3 µM) and higherexposure times (24 h) (Protocol b). Cell cycle analysis after both protocols of PTN-PDTrevealed a high percentage of sub-G1 cells. PTN was found to be taken up by K562 cellsmainly by passive diffusion.Other tumour cells such as ovary cancer IGROV-1 and LM2 mammary carcinoma and thenormal keratinocytes HaCaT were also photosensitised with PTN-PDT.We conclude that PTN is a promising photosensitiser for PDT of superficial malignanciesand purging of leukaemic cells, upon illumination with blue light. We propose the use ofthis light wavelength to replace the Vis-UVA lamps generally employed for thephotosensitisation of anthraquinones.