Evaluation of subdosis effect in photodynamic therapy at the cellular level on implants tumor growth

• Grant number: 22/11516-7
• Support Opportunities: Scholarships in Brazil - Program to Stimulate Scientific Vocations
• Start date until: January 09, 2023
• End date until: February 28, 2023
• Field of knowledge: Biological Sciences - Biophysics - Cellular Biophysics
• Principal Investigator: Vanderlei Salvador Bagnato
• Grantee: Tiago de Paula Bianchi
• Host Institution: Instituto de Física de São Carlos (IFSC). Universidade de São Paulo (USP). São Carlos , SP, Brazil

Abstract

Cancer has been one of the leading causes of death in the world. Photodynamic therapy (PDT) has been an increasingly accepted and widespread treatment option. The treatment efficacy depends on each of the three fundamental elements (photosensitizer, light, and oxygen) present in sufficient quantity throughout the tumor. However, there is a concern and need to understand if the application of PDT can cause any growth pattern when applicated in under conditions that are not sufficient to cause damage to the entire tumor extension. This study aims to investigate the tumor growth rate for different cell lines when PDT subdosis is applicated before the induction. Thirty female mice of the balb/c nude type will are used, divided into 6 groups, composed of cell lines of murine melanoma (B16F10) and human squamous cell carcinoma (A-431) types. The cells will be incubated with Photogem® with a concentration of 5 ¼g/mL for 4 hours and treated with PDT subdosis using fluences of 2 or 10 J/cm2 prior to induction in the animals. Tumor dimensions will be measured daily, for a period of up to 20 days, and the volume will be estimated considering a spherical volume. The growth rate of volume will be evaluated for each of the groups. The project may indicate the effect of photo-oxidation of PDT on the growth of subsequent cells, when under clinical conditions. In addition, this is within our traditional studies and is being planned for execution in the 50 days of the internship program. (AU)