Run for your life: an integrated virtual tissue platform for incorporating exercise oncology into immunotherapy.

The purpose of this paper is to introduce a novel in silico platform for simulating early-stage solid tumor growth and anti-tumor immune response. We present the model, test the sensitivity and robustness of its parameters, and calibrate it with clinical data from exercise oncology experiments which offer a natural biological backdrop for modulation of anti-tumor immune response. We then perform two virtual experiments with the model that demonstrate its usefulness in guiding pre-clinical and clinical studies of immunotherapy. The first virtual experiment describes the intricate dynamics in the tumor microenvironment between the tumor and the infiltrating immune cells. Such dynamics is difficult to probe during a pre-clinical study as it requires significant redundancy in lab animals and is prohibitively time-consuming and labor-intensive. The result is a series of spatiotemporal snapshots of the tumor and its microenvironment that can serve as a platform to test mechanistic hypotheses on the role and dynamics of different immune cells in anti-tumor immune response. The second virtual experiment shows how dosage and/or frequency of immunotherapy drugs can be optimized based on the aerobic fitness of the patient, so that possible adverse side effects of the treatment can be minimized.

Endurance training slows breast tumor growth in mice by suppressing Treg cells recruitment to tumors.

BACKGROUND: Aerobic exercise has been shown to slow tumor progression in rodents and humans, but the mechanisms behind this effect are still unclear. Here we show that aerobic exercise in the form of chronic endurance training suppresses tumor recruitment of FoxP3+ Treg cells thus enhancing antitumor immune efficiency. METHODS: Adult wild-type and athymic BALB/c female mice were endurance-trained for 8 weeks. Circulating leukocytes as well as muscle and liver mtDNA copy number were compared to aged-matched concurrent sedentary controls to establish systemic effects. 4 T1 murine mammary tumor cells were injected subcutaneously to the 4th mammary pad at the end of the training period. Tumor growth and survival rates were compared, together with antitumor immune response. RESULTS: Exercised wild-type had 17% slower growth rate, 24% longer survival, and 2-fold tumor-CD+ 8/FoxP3+ ratio than sedentary controls. Exercised athymic BALB/c females showed no difference in tumor growth or survival rates when compared to sedentary controls. CONCLUSIONS: Cytotoxic T cells are a significant factor in endurance exercise-induced suppression of tumor growth. Endurance exercise enhances antitumor immune efficacy by increasing intratumoral CD8+/FoxP3+ ratio.