Fig. 4

Dose-modifying factor of ganetespib in A549 cells in response to photon, proximal SOBP, and distal SOBP irradiation. A549 cells irradiated with photon reference IR do not exhibit a radiosensitizing effect upon ganetespib treatment (A). In contrast, the linear-quadratic model highlights differences in A549 cells upon irradiation with B proximal SOBP and C distal SOBP protons in dependence of sham or ganetespib treatment. Consequently, the DMF of ganetespib at D 50%, E 25%, and F 10% cell survival is significantly higher in A549 cells irradiated with either of the two proton modalities compared to reference photon IR. Proximal and distal SOBP corresponds to a LET of 2.1 respectively 4.5 keV/μm and statistical testing was performed by unpaired, two-tailed t test with Welch’s Correction with error bars indicating the standard deviation