Supplementary Table S1: Evaluation of M3814 (MSC2490484) in kinase assays Supplementary Table S2: In vitro activity of M3814 in combination with a single dose of gamma radiation in a panel of 93 cell lines. Supplementary Table S3: Pharmacokinetic data for M3814 Supplementary Figure S1: 3 Gy IR - M3814 combination profiling: Bliss data Supplementary Figure S2: 70 Drug - M3814 combination profiling: Bliss data Supplementary Figure S3: Concentration of M3814 in vitro, following administration of M3814 intravenously (0.2 mg/kg) or orally (0.5 mg/kg) Supplementary Figure S4: Additional 1-week IR combination efficacy data (A549, BxPC3, Capan-1, HCT-116) Supplementary Figure S5: Scheduling of M3814 relative to IR Supplementary Figure S6: Body weight curves from efficacy studies
ARTICLE ABSTRACT
Physical and chemical DNA-damaging agents are used widely in the treatment of cancer. Double-strand break (DSB) lesions in DNA are the most deleterious form of damage and, if left unrepaired, can effectively kill cancer cells. DNA-dependent protein kinase (DNA-PK) is a critical component of nonhomologous end joining (NHEJ), one of the two major pathways for DSB repair. Although DNA-PK has been considered an attractive target for cancer therapy, the development of pharmacologic DNA-PK inhibitors for clinical use has been lagging. Here, we report the discovery and characterization of a potent, selective, and orally bioavailable DNA-PK inhibitor, M3814 (peposertib), and provide in vivo proof of principle for DNA-PK inhibition as a novel approach to combination radiotherapy. M3814 potently inhibits DNA-PK catalytic activity and sensitizes multiple cancer cell lines to ionizing radiation (IR) and DSB-inducing agents. Inhibition of DNA-PK autophosphorylation in cancer cells or xenograft tumors led to an increased number of persistent DSBs. Oral administration of M3814 to two xenograft models of human cancer, using a clinically established 6-week fractionated radiation schedule, strongly potentiated the antitumor activity of IR and led to complete tumor regression at nontoxic doses. Our results strongly support DNA-PK inhibition as a novel approach for the combination radiotherapy of cancer. M3814 is currently under investigation in combination with radiotherapy in clinical trials.
