A threshold dose distribution approach for the study of PDT resistance development A threshold distribution approach for the study of PDT resistance

Autor(es)

Gonsalves de Faria, Clara Maria ^[1] ; Inada, Natalia Mayumi ^[1] ; Vollet-Filho, Jose Dirceu ^[1] ; Bagnato, Vanderlei Salvador ^[1]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Sao Carlos Inst Phys, Av Trabalhador Sao Carlense 400, BR-13566590 Sao Carlos, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY; v. 182, p. 85-91, MAY 2018.
• Citações Web of Science: 1

Resumo

Photodynamic therapy (PDT) is a technique with well-established principles that often demands repeated applications for sequential elimination of tumor cells. An important question concerns the way surviving cells from a treatment behave in the subsequent one. Threshold dose is a core concept in PDT dosimetry, as the minimum amount of energy to be delivered for cell destruction via PDT. Concepts of threshold distribution have shown to be an important tool for PDT results analysis in vitro. In this study, we used some of these concepts for demonstrating subsequent treatments with partial elimination of cells modify the distribution, which represents an increased resistance of the cells to the photodynamic action. HepG2 and HepaRG were used as models of tumor and normal liver cells and a protocol to induce resistance, consisted of repeated PDT sessions using Photogem (R) as a photosensitizer, was applied to the tumor ones. The response of these cells to PDT was assessed using a standard viability assay and the dose response curves were used for deriving the threshold distributions. The changes in the distribution revealed that the resistance protocol effectively eliminated the most sensitive cells. Nevertheless, HepaRG cell line was the most resistant one among the cells analyzed, which indicates a specificity in clinical applications that enables the use of high doses and drug concentrations with minimal damage to the surrounding normal tissue. (AU)

• Processo FAPESP: 09/54035-4 - EMU: facility para estudos avançados de materiais nanoestruturados e biossistemas / FAMA
• Beneficiário: Igor Polikarpov
• Modalidade de apoio: Auxílio à Pesquisa - Programa Equipamentos Multiusuários
• Processo FAPESP: 13/07276-1 - CEPOF - Centro de Pesquisa em Óptica e Fotônica
• Beneficiário: Vanderlei Salvador Bagnato
• Modalidade de apoio: Auxílio à Pesquisa - Centros de Pesquisa, Inovação e Difusão - CEPIDs
• Processo FAPESP: 15/06579-6 - Distribuição de dose limiar e suas causas e consequências em terapia fotodinâmica
• Beneficiário: Clara Maria Gonçalves de Faria
• Modalidade de apoio: Bolsas no Brasil - Mestrado