Photodynamic Therapy of Breast Cancer in Animal Models and Their Potential Use in Clinical Trials-Role of the Photosensitizers: A Review

In this article, we reviewed the use of photodynamic therapy (PDT) for breast cancer (BC) in animal models. These in vivo models imitate the cancer disease progression, aid diagnosis, as well as create opportunities to assess treatment during the approval process for the new drug. BC ranks first among women's cancers. Nowadays, there are many diagnostic methods and therapy options for BC but the majority of them have severe side effects. This article discusses the advantages and some disadvantages of the use of small and large animals used for BC models. A literature review showed that the majority of studies have used large animal models, and recently there has been more interest in developing BC in small animal models. BC cell lines such as MCF-7, BT-474, MDA-MB-231, and 4T1 are commercially available for two-dimensional and three-dimensional in vitro cell cultures and subcutaneous models. The purpose of this article is to discuss the performance of PDT in animal models and its further clinical implications. PDT is known to be a non-invasive therapy, which uses monochromatic light and energy to excite photosensitizers (PSs) for the generation of reactive oxygen species as the required factors. Herein, we discuss the use of five photosensitizers in BC models such as chlorin e6 (Ce6), methylene blue, indocyanine green, 5-aminolevulinic acid, and meta-tetra(hydroxyphenyl)chlorin. The database PubMed and Scopus were searched for keywords: 'photodynamic therapy', 'breast cancer', 'animal model', 'clinical studies', and 'photosensitizer(s)'. The PDT search results in animal experiments and its effect on a living organism indicate the possibility of its application in clinical trials on women with local and disseminated BC. The availability and accessibility of small and large BC animal models enable the progress and trial of cancer drugs for innovative technologies and new diagnostics and treatments.