Association of photonic techniques and radiotherapy to optimize the tumoral response to ionizing radiation

• Grant number: 21/08746-8
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Start date: November 01, 2021
• End date: March 31, 2022
• Field of knowledge: Physical Sciences and Mathematics - Physics
• Agreement: CNPq - INCTs
• Principal Investigator: Vanderlei Salvador Bagnato
• Grantee: Clara Maria Gonçalves de Faria
• Host Institution: Instituto de Física de São Carlos (IFSC). Universidade de São Paulo (USP). São Carlos , SP, Brazil
• Associated research grant: 14/50857-8 - National Institute in Basic Optics and Applied to Life Sciences, AP.TEM

Abstract

Radiotherapy is one of the main treatment strategies in oncology. However, optimizing the technique is desired to increase patient cure rates, especially in radioresistant tumors, and decrease side effects in healthy tissues. Photobiomodulation Therapy (PBMT) consists of the application of light in order to modify cellular processes such as proliferation, tissue repair and analgesia. In addition to these effects, experimental data from some studies are strong evidence that PBMT can act to modulate the cell cycle and increase tissue oxygenation, which are determining factors in the outcome of a radiotherapy treatment. Photodynamic therapy is, in turn, an oncological treatment that leads to tumor death by combining a photoactivatable drug and light, generating reactive oxygen species. Due to its mechanism it causes different types of death compared to radiotherapy, so the combination of these can be synergistic. Therefore, this project proposes to investigate the combination of these techniques to develop a protocol that increases tumor damage and treatment effectiveness. In a previous work, tumor regression was demonstrated by the combination of PBMT and RT. In this work, the contribution of vascular and tissue oxygenation to this result will be investigated in vivo. Regarding PDT-RT, in vitro experiments will enable the study of the effect of this combination on cell viability and death mechanisms involved, especially in radioresistant tumor models. From this investigation, the protocols to be analyzed in vivo will be determined. The objective of these experiments is to evaluate the combination of techniques in a model of greater biological complexity, and to evaluate tumor damage and animal survival in order to propose a protocol that can improve tumor response to ionizing radiation. (AU)