title: Chemical inhibitor targeting the replication protein A-DNA interaction increases the efficacy of Pt-based chemotherapy in lung and ovarian cancer.
abstract: Platinum-based chemotherapeutics exert their therapeutic efficacy via the formation of DNA adducts which interfere with DNA replication, transcription and cell division and ultimately induce cell death. Repair and tolerance of these Pt-DNA lesions by nucleotide excision repair (NER) and homologous recombination (HR) can substantially reduce the effectiveness of therapy. Inhibition of these repair pathways, therefore, holds the potential to sensitize cancer cells to Pt treatment and increase clinical efficacy. Replication Protein A (RPA) plays essential roles in both NER and HR, along with its role in DNA replication and DNA damage checkpoint activation. Each of these functions is, in part, mediated by RPA binding to single-stranded DNA (ssDNA). Here we report the synthesis and characterization of novel derivatives of RPA small molecule inhibitors and their activity in models of epithelial ovarian cancer (EOC) and non-small cell lung cancer (NSCLC). We have synthesized analogs of our previously reported RPA inhibitor TDRL-505 and determined the structure-activity relationships. These data led us to the identification of TDRL-551, which exhibited a greater than 2-fold increase in in vitro activity. TDRL-551 showed synergy with Pt in tissue culture models of EOC and in vivo efficacy, as a single agent and in combination with platinum, in a NSCLC xenograft model. These data demonstrate the utility of RPA inhibition in EOC and NSCLC and the potential in developing novel anticancer therapeutics that target RPA-DNA interactions.
authors.affiliation: Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN, 46202, USA.
authors.forename: Akaash K
authors.initials: AK
authors.lastname: Mishra
authors.affiliation: Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, 46202, USA.
authors.forename: Silvana S
authors.initials: SS
authors.lastname: Dormi
authors.affiliation: NERx Biosciences Inc. 351W. 10th Street, Suite 510, Indianapolis, IN 46202, USA.
authors.forename: Alaina M
authors.initials: AM
authors.lastname: Turchi
authors.affiliation: NERx Biosciences Inc. 351W. 10th Street, Suite 510, Indianapolis, IN 46202, USA.
authors.forename: Derek S
authors.initials: DS
authors.lastname: Woods
authors.affiliation: Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN, 46202, USA; Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, 46202, USA; NERx Biosciences Inc. 351W. 10th Street, Suite 510, Indianapolis, IN 46202, USA. Electronic address: jturchi@iu.edu.
authors.forename: John J
authors.initials: JJ
authors.lastname: Turchi
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000008:administration & dosage*; D002945:Cisplatin / Q000008:administration & dosage; D044704:DNA, A-Form / Q000037:antagonists & inhibitors / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D016503:Drug Delivery Systems / Q000379:methods*; D005260:Female; D006801:Humans; D016688:Mice, Inbred NOD; D016513:Mice, SCID; D010051:Ovarian Neoplasms / Q000188:drug therapy* / Q000378:metabolism*; D017671:Platinum Compounds / Q000008:administration & dosage*; D016896:Treatment Outcome
chemical_list: D000970:Antineoplastic Agents; D044704:DNA, A-Form; D017671:Platinum Compounds; D002945:Cisplatin
keywords: Cisplatin; Combination therapy; DNA repair; Drug discovery; Replication protein A