Figure 5.

Effect of PARP inhibition on double-strand break induction after PRRT in ex vivo cultured NET slices. (A) Hematoxylin and eosin staining of the fresh neuroendocrine pancreatic tumor; islands of NET cells are surrounded by stromal cells. (B) Immunofluorescent staining of 53BP1 (red) and DAPI (blue) of a field of cells at 2 time points after treatment (0 days and 3.5 days after treatment). Tissue slices were non-treated (NT) or treated with ¹⁷⁷Lu-DOTA-TATE and afterwards treated or not with PARP inhibitor (PARPi). Scale bar = 5 μm. (C) Quantification of 53BP1 foci of different fields of cells at 2 locations per tumor slice of on average 660 cells per condition at different timepoints after treatment. Error bars represent the SEM. Statistics represent the comparison between ¹⁷⁷Lu-DOTA-TATE and ¹⁷⁷Lu-DOTA-TATE + PARPi. * p<0.05 and ** p<0.01.