resumo
Melanoma is the most dangerous form of skin cancer, with an abrupt growth of its incidence over the last years. It is extremely resistant to traditional treatments such as chemotherapy and radiotherapy, but therapies for this cancer are gaining attention. Photodynamic therapy (PDT) is considered an effective modality to treat several types of skin cancers and can offer the possibility to treat one of the most aggressive ones: melanoma. In this work, the effect of PDT on a melanotic cell line (B16F10 cells) was assessed by exposing cultured cells to 5,10,15-tris(pentafluorophenyl)-20-(4-pyridyl)porphyrin (PS1) and to its chlorin (PS2) and isobacteriochlorin (PS3) corresponding derivatives and red LED light (lambda = 660 +/- 20 nm). The PDT effect in the cells' viability was measured using the MTT assay. The cell apoptosis was quantified by flow cytometry, and the subcellular localization of the photosensitizer was determined by fluorescence microscopy. In addition, the ability of PS2 to generate superoxide radicals was qualitatively assessed by tyrosine nitration. The results show that the efficiency of the PDT process is dependent on the structure of the PS and on their ability to produce singlet oxygen. Besides that, the photoactivation efficiency is highly dependent on the cellular sublocalization of the PS and on its cellular uptake and singlet oxygen production. We also found that the resistant cell line B16F10 has distinctive chlorin, isobacteriochlorin, or porphyrin-specific resistance profiles. Furthermore, it is shown that the highly fluorescent chlorin derivative PS2 can also be considered in imaging diagnostics.
palavras-chave
SUBCELLULAR-LOCALIZATION; PHOTOPHYSICAL PROPERTIES; THERAPY; CANCER; PEROXYNITRITE; MECHANISMS; PHOTOBIOMODULATION; BACTERIOCHLORINS; PHOTOSENSITIZERS; TYROSINE
categoria
Nanoscience & Nanotechnology; Materials Science, Biomaterials
autores
Castro, KADF; Ramos, L; Mesquita, M; Biazzotto, JC; Moura, NMM; Mendes, RF; Paz, FAA; Tome, AC; Cavaleiro, JAS; Simoes, MMQ; Faustino, MAF; Jager, AV; Nakagaki, S; Neves, MGPMS; Da Silva, RS
nossos autores
Filipe Alexandre Almeida Paz
Investigador Principal
Ricardo Faria Mendes
Investigador Júnioragradecimentos
The authors are grateful to CNPq, CAPES, FAPESP grant 2019/19448-8 and Universidade de Sa~o Paulo for financial support. Thanks are also due to the University of Aveiro and FCT for the financial support to LAQV-REQUIMTE (UIDB/50006/2020) and CICECO-Aveiro Institute of Materials (FCT ref. UIDB/50011/2020 & UIDP/50011/2020)), financed by national funds through the FCT/MEC and when appropriate cofinanced by FEDER under the PT2020 Partnership Agreement. We further wish to thank CICECO for specific funds toward the purchase of the single-crystal X-ray diffractometer. K. A.D. F. Castro thanks CAPES for the postdoctoral scholarship awarded (PNPD/CAPES). The research contract of N.M.M. Moura (REF.-048-88-ARH/2018) is funded by national funds (OE), through FCT -Fundaccommaa~o para a Cie<^>ncia e a Tecnologia, I.P., in the scope of the framework contract foreseen in the numbers 4, 5, and 6 of the article 23, of the Decree-Law 57/2016, of August 29, changed by Law 57/2017, of July 19. R.F.M. and M.M. also gratefully acknowledge FCT for the Junior Research Position (CEECIND/00553/2017) and doctoral grant (SFRH/BD/112317/2015), respectively.