Figure 4. MeOX sensitizes cells to ß-lap by potentiating DNA damage and PARP1 hyperactivation.

(A) MeOX enhances DSB formation in MiaPaca2 cancer cells. Average γH2AX foci/nuclei were assessed in ß-lap-treated (μM, 2 h) MiaPaca2 cells, + MeOX (12 mM) at 15 and 30 min during exposure. H₂O₂ (0.5 mM, 15 min) was used as a positive control. (B) Average 53BP1 foci/nuclei in ß-lap-treated (μM, 2 h) MiaPaca2 cells, ±12 mM MeOX over time (h). Graph represents average foci of three separate experiments. (C) Relative NAD⁺ levels in MiaPaca2 cells 2 h after treatment with ß-lap, ±12 mM MeOX, with or without Rucaparib (25 μM) in sextuplicate, means ± SEM. (D) Relative ATP levels in ASPC1 cells 2 h after treatment with ß-lap, ±12 mM MeOX. (E) Western blot quantification of relative PAR-PARP1 formation (using α-tubulin for loading) in MiaPaca2 cells 20 min after exposure to various doses of ß-lap ±12 mM MeOX. (F) Clonogenic survival of MiaPaca2 cells pre-treated with 5 μM BAPTA-AM (Ca²⁺ chelator) for 30 min followed by treatment with ß-lap (μM, 2 h), ±12 mM MeOX. Data represent survival means ±SEM from quadruplicate samples.