ve-821 and Neoplasms

Chemoresistance, radioresistance, and the challenge of achieving complete resection are major driving forces in the search for more robust and targeted anticancer therapies. Targeting the DNA damage response has recently attracted research interest, as these processes are enhanced in tumour cells. The major replication stress responder is ATM and Rad3-related (ATR) kinase, which is attracting attention worldwide with four drug candidates currently in phase I/II clinical trials. This review addresses a potent and selective small-molecule ATR inhibitor, which is known as VX-970 (also known as berzosertib or M6620), and summarizes the existing preclinical data to provide deep insight regarding its real potential. We also outline the transition from preclinical to clinical studies, as well as its relationships with other clinical candidates (AZD6738, VX-803 [M4344], and BAY1895344). The results suggest that VX-970 is indeed a promising anticancer drug that can be used both as monotherapy and in combination with either chemotherapy or radiotherapy strategies. Based on patient anamnesis and biomarker identification, VX-970 could become a valuable tool for oncologists in the fight against cancer.

Topics: Animals; Antineoplastic Agents; Antineoplastic Combined Chemotherapy Protocols; Ataxia Telangiectasia Mutated Proteins; Drug Discovery; Drug Synergism; Humans; Isoxazoles; Molecular Targeted Therapy; Neoplasms; Protein Kinase Inhibitors; Pyrazines; Signal Transduction; Sulfones; Treatment Outcome

Modulation of DNA repair pathways in oncology has been an area of intense interest in the last decade, not least as a consequence of the promising clinical activity of poly(ADP-ribose) polymerase (PARP) inhibitors. In this review article, we highlight inhibitors of the phosphatidylinositol 3-kinase related kinase (PIKK) family as of potential interest in the treatment of cancer, both in combination with DNA-damaging therapies and as stand-alone agents.

Topics: Animals; Ataxia Telangiectasia Mutated Proteins; Cell Cycle Proteins; DNA; DNA Repair; DNA-Activated Protein Kinase; DNA-Binding Proteins; Humans; Models, Molecular; Neoplasms; Protein Kinase Inhibitors; Protein Serine-Threonine Kinases; Tumor Suppressor Proteins

Homologous recombination (HR) is required for faithful repair of double-strand DNA breaks. Defects in HR repair cause severe genomic instability and challenge cellular viability. Paradoxically, various cancers are HR defective and have apparently acquired characteristics to survive genomic instability. We aimed to identify these characteristics to uncover therapeutic targets for HR-deficient cancers. Cytogenetic analysis of 1143 ovarian cancers showed that the degree of genomic instability was correlated to amplification of replication checkpoint genes ataxia telangiectasia and Rad3-related kinase (ATR) and CHEK1. To test whether genomic instability leads to increased reliance on replication checkpoint signaling, we inactivated Rad51 to model HR-related genomic instability. Rad51 inactivation caused defective HR repair and induced aberrant replication dynamics. Notably, inhibition of Rad51 led to increased ATR/checkpoint kinase-1 (Chk1)-mediated replication stress signaling. Importantly, inhibition of ATR or Chk1 preferentially killed HR-deficient cancer cells. Combined, our data show that defective HR caused by Rad51 inhibition results in differential sensitivity for ATR and Chk1 inhibitors, implicating replication checkpoint kinases as potential drug targets for HR-defective cancers.

Topics: Antineoplastic Agents; Ataxia Telangiectasia Mutated Proteins; Cell Survival; Checkpoint Kinase 1; Drug Resistance, Neoplasm; HeLa Cells; Homologous Recombination; Humans; MCF-7 Cells; Molecular Targeted Therapy; Neoplasms; Protein Kinases; Pyrazines; Signal Transduction; Sulfones; Thiophenes; Urea