Study of Proton Beam Influence on the Growth Dynamics and Viability of 3D Cell Spheroids Formed From 4T1 Carcinoma Cells

Background: Proton therapy is considered one of the most promising methods in the treatment of complex localized tumors, but still has some shortcomings, which requires the development of new approaches to improve its effectiveness. One of the most promising approaches is the use of radiosensitizers that can enhance the radiation-induced effects of a proton beam. However, the use of 2D tumor cell models for screening potential radiosensitizers is insufficient for the effective translation of the experimental data to the in vivo level. 3D cellular spheroids are a convenient and relevant model for studying new approaches in the therapy of solid tumors, since they allow simulating the conditions of the microenvironment of tumor cells and simulating in vivo conditions, including the presence of an intercellular matrix and the formation of a certain zonality.

Purpose: To create an experimental model of a tumor spheroid based on 4T1 tumor cells irradiated with a proton beam for screening potential nanoradiosensitizers.

Material and methods: In vitro biological activity was assessed using a 4T1 cell line (mouse carcinoma) culture. The hanging drop method was used to form cell spheroids. The spheroids were irradiated with a proton beam at the Bragg peak on at a dose of 0–12 Gr using the “Prometheus” therapeutic proton complex . The clonogenic test was used to analyze the viability and mitotic activity of the cells after irradiation. The growth dynamics of irradiated 3D spheroids has been assessing by analyzing micromorphometry for 8 days after irradiation.