Noninvasive Imaging and Quantification of Radiotherapy-Induced PD-L1 Upregulation with ⁸⁹Zr-Df-Atezolizumab.

ABSTRACT: Immune checkpoint expression is highly dynamic, and combination treatments including radiotherapy can particularly modulate this expression. PET imaging using ⁸⁹Zr-Df-atezolizumab can provide insight into the levels of PD-L1 variation following radiotherapy treatments. In vitro screening was used to monitor PD-L1 expression by lung cancer cells following radiotherapy. Mice bearing PD-L1+ (H460) or PD-L1- (A549) tumors were subjected to various external beam radiotherapy regimens and then imaged using ⁸⁹Zr-Df-atezolizumab PET. ROI analysis and ex vivo biodistribution studies were employed to quantify tracer accumulations. H460 cells were found to have PD-L1 expression at baseline, and this expression increased following daily radiotherapy of 5 fractions of 2 Gy. PD-L1

SUBMITTER: Ehlerding EB 

PROVIDER: S-EPMC6521689 | biostudies-literature | 2019 May

REPOSITORIES: biostudies-literature