ESTRO 2025 - Abstract Book

S4000

Radiobiology - Tumour radiobiology

ESTRO 2025

Results: Previously, we have shown that Mito-PEG-ATO reduces hypoxia in B16OVA.HRE and MC38.HRE spheroid models. As a next step, we performed a pre-clinical study, where tumor-bearing mice were treated with Mito-PEG-ATO. Treatment with Mito-PEG-ATO did not result in a reduction of pimonidazole fraction on MOC1.3D5 tumor sections and the fraction of immune cells was not increased. Moreover, serum lactate levels were not elevated following treatment with Mito-PEG-ATO (9.8 vs. 10.2 mM) (Fig. 1.). As Mito-PEG-ATO was not able to alleviate hypoxia in MOC1.3D5 tumors, we continue our experiments with MitoTam. MitoTam alleviates hypoxia in a dose-dependent manner in B16OVA.HRE and MC38.HRE spheroid models. In both spheroid models, treatment with at least 2.5 μM MitoTam reduced hypoxia significantly with 50% (Figure 2). In ongoing experiments we will determine whether MitoTam is able to reduce hypoxia in mouse tumor models.