In Vitro Evaluation of PARP1 Inhibitor Olaparib‐Cyanine Dye Conjugate for the Treatment of Glioblastoma

Inhibition of DNA damage repair is a common mechanism to induce cancer cell death and, therefore, to treat cancers such as breast, prostate and ovarian cancer. This approach, although very attractive, has not been feasible for treating brain tumours due to the stringent structural features necessary for pharmaceutical agents to cross the blood-brain barrier (BBB). This study presents the proof of concept in vitro cellular activity of PARP1 (Poly(ADP-ribose) polymerase 1) enzyme inhibitor olaparib conjugated with a known BBB-crossing heptamethine cyanine dye. We also present evidence for cellular uptake and PARP1 inhibition by the conjugate, which contributes to the observed improvement in potency.