Supplementary Figure 3 from Simultaneous Targeting of DNA Polymerase Theta and PARP1 or RAD52 Triggers Dual Synthetic Lethality in Homologous Recombination–Deficient Leukemia Cells
posted on 2023-10-02, 07:43authored byKatherine Sullivan-Reed, Monika M. Toma, Malgorzata Drzewiecka, Margaret Nieborowska-Skorska, Reza Nejati, Adam Karami, Mariusz A. Wasik, Tomasz Sliwinski, Tomasz Skorski
S3. Simultaneous inhibition of Polθ helicase and DNA polymerase
activity exerted synergistic effect against RAD54-/- leukemia cells.
Funding
National Cancer Institute (NCI)
United States Department of Health and Human Services
DNA polymerase theta (Polθ, encoded by POLQ gene) plays an essential role in Polθ-mediated end-joining (TMEJ) of DNA double-strand breaks (DSB). Inhibition of Polθ is synthetic lethal in homologous recombination (HR)-deficient tumor cells. However, DSBs can be also repaired by PARP1 and RAD52-mediated mechanisms. Because leukemia cells accumulate spontaneous DSBs, we tested if simultaneous targeting of Polθ and PARP1 or RAD52 enhance the synthetic lethal effect in HR-deficient leukemia cells. Transformation potential of the oncogenes inducing BRCA1/2-deficiency (BCR-ABL1 and AML1-ETO) was severely limited in Polq−/−;Parp1−/− and Polq−/−;Rad52−/− cells when compared with single knockouts, which was associated with accumulation of DSBs. Small-molecule inhibitor of Polθ (Polθi) when combined with PARP or RAD52 inhibitors (PARPi, RAD52i) caused accumulation of DSBs and exerted increased effect against HR-deficient leukemia and myeloproliferative neoplasm cells.
In conclusion, we show that PARPi or RAD52i might improve therapeutic effect of Polθi against HR-deficient leukemias.