Figure 1.
DNA damage response in AR42J cells following ionizing irradiation.
(A) and (B) Cells were irradiated with 5 Gy and time-dependent DNA damage response was assessed over 24 h using western blot analysis.
Figure 2.
Viability of AR42J cells at 48225Ac-DOTATOC (A) and 177Lu-DOTATOC (B).
Figure 3.
Number of γH2AX foci in AR42J cells at 24 and 48 h after incubation with 225Ac-DOTATOC (left) and 177Lu-DOTATOC (right).
(A) shows representative images from all activity levels, (B) shows quantification of γH2AX foci and (C) shows two representative examples for pan nuclear staining after high dose 225Ac-DOTATOC treatment.
Figure 4.
Comparison of cell viability and the number of γH2AX foci in AR42J cells at 48 h after incubation with 225Ac-DOTATOC and 177Lu-DOTATOC.
Figure 5.
Single-cell gel electrophoresis (alkaline comet assay) of AR42J cells at 24 h and 48 h after incubation with 225Ac-DOTATOC (A) and 177Lu-DOTATOC (B).
DNA damage was calculated by the tail moment, the most frequent used parameter of comet features. SubG1 fraction of AR42J cells at 48 and 72 h after incubation with 225Ac-DOTATOC (C) and 177Lu-DOTATOC (D).
Figure 6.
Cell-cycle distribution of AR42J cells at 48 h after incubation with 225Ac-DOTATOC (left) and 177Lu-DOTATOC (right) (SD <15%).
Figure 7.
Immunofluorescence staining of DNA double strand breaks (γH2AX) in AR42J tumors after treatment with 47 kBq 225Ac-DOTATOC, 30 MBq of 177Lu-DOTATOC, 1 µg DOTATOC (unlabelled), or PBS.
(A) Representative images, (B) and quantification of γH2AX- positive cells. Scale bar (white) corresponds to 25 µm. (C) Growth delay after treatment with equitoxic doses of 225Ac-DOTATOC (n = 3, 44kBq/mouse) and 177Lu-DOTATOC (n = 4, 34 MBq/mouse) versus untreated control (n = 4).
Table 1.
Physical properties of the radio-isotopes and calculation of their relative biological effectiveness on basis of 48 h in vitro cytotoxicity.