Figure 1. ¹⁷⁷Lu-octreotate uptake and PARylation of proteins in BON-1 and NCI-H727 cells.

(A) Uptake of ¹⁷⁷Lu-octreotate in BON-1 and NCI-H727 cells. Both the cell lines were exposed to 2.75 MBq/mL of ¹⁷⁷Lu-octreotate or 2.75 MBq/mL of ¹⁷⁷Lu-DTPA for 5 days. Each data point, derived from six replicates per experimental condition, represents mean ± SEM. The ^* indicates significant differences (P ≤ 0.05) in uptake of ¹⁷⁷Lu-octreotate as compared to that of ¹⁷⁷Lu-DTPA in both the cell lines. (B-C) ¹⁷⁷Lu-octreotate-induced reduction in cell viability of BON-1 and NCI-H727 cells. Both the cell lines were exposed to 2.75 MBq/mL of ¹⁷⁷Lu-octreotate or 2.75 MBq/mL of ¹⁷⁷Lu-DTPA for 5 days followed by five more days of incubation of cells in medium without radiolabel. The viability was determined at day 5 and day 10 of the protocol. The cell count in each treatment group is expressed as percent of number of viable cells in untreated control. The average of six replicates per experimental condition is plotted as mean ± SEM, with ^* indicating a significant difference in %viability of cells on day 5 and day 10 in each treatment group. (D) PARP inhibitor DHQ inhibits the PAR formation by PARP1 induced by ¹⁷⁷Lu-octreotate in BON-1 and NCI-H727 cells. Both the cell lines were treated with 2.75 MBq/mL of ¹⁷⁷Lu-octreotate in presence and absence of DHQ for indicated time points and the cell extracts were immunoblotted for PAR and PARP1.