Danusertib

DNA helicases are essential to genomic stability by regulating DNA metabolisms and their loss-of-function mutations lead to genomic instability and predisposition to cancer. Paradoxically, overexpression of DNA helicases is observed in several cancers. Here we analyzed genomic and molecular alterations in 12 important DNA helicases in TCGA pan-cancers to provide an overview of their aberrations. Significant expression heterogeneity of 12 DNA helicases was observed. We calculated DNA helicase score (DHS) based on their expression, and categorized tumors into high, low and intermediate subtypes. High DHS subtypes were robustly associated with stemness, proliferation, hyperactivated oncogenic signaling, longer telomeres, total mutation burden, copy number alterations (CNAs) and shorter survival. Importantly, tumors with high DHSs exhibited stronger expression of alternative end-join (alt-EJ) factors, indicative of sensitivity to chemo- and radio-therapies. High DHSs were also associated with homologous recombination deficiency (HRD), BRCA1/2 mutations and sensitivity to PARP inhibitors. Moreover, several drugs are identified to inhibit DNA helicases, with the Auror A kinase inhibitor Danusertib as the strongest candidate that was confirmed experimentally. The aberrant expression of DNA helicases was associated with CNAs, DNA methylation and m6A regulators. Our findings thus reveal widespread dysregulation of DNA helicases and their broad connection with featured oncogenic aberrations across human cancers. The close association of DHS with the alt-EJ pathway and HRD, and identification of Danusertib as a putative DNA helicase inhibitor have translational significance. Taken together, these findings will contribute to DNA helicase-based cancer therapy.

Evidence for the relevance of Epstein-Barr virus (EBV) in various types of cancer has expanded; however, the definitive mechanism of EBV-induced oncogenesis remains ambiguous. The purpose of this study was to identify the relevance of aurora kinases in EBV-induced carcinogenesis, and the cellular responses to danusertib, a pan-aurora kinase inhibitor. The underlying signaling mechanism in EBV-transformed B-cells was also investigated.

Western blotting was performed on EBV-transformed B-cells and EBV-positive lymphoma cells to identify aurora kinase expression. Cellular responses of EBV-transformed B-cells to danusertib were investigated using AlamaBlue assay and apoptosis analysis. To evaluate the underlying signaling mechanisms of danusertib-induced apoptosis, cleavage of caspase cascade molecules, endoplasmic reticulum (ER) stress-associated molecule activation, and intracellular Ca²⁺ levels were evaluated using western blotting, flow cytometry, and inhibition assays.

Expression of both aurora kinase A and B was gradually increased in EBV-infected B-cells and two EBV-positive B lymphoma cell lines. Danusertib significantly suppressed EBV-transformed B-cell proliferation in a dose-dependent manner. Danusertib induced apoptosis and cell cycle arrest through disruption of mitochondrial membrane potential in EBV-transformed B-cells in a dose-dependent and time-dependent manner. Moreover, danusertib induced cleavage of caspases, ER stress-associated molecule activation, and intracellular Ca²⁺ release from ER to cytoplasm in EBV-transformed B-cells, while BAPTA-AM, a calcium chelator, inhibited danusertib-induced apoptosis.

Danusertib treatment led to apoptosis of EBV-transformed B-cells through ER stress-associated proteins and mitochondrial caspase activation. These results suggest that aurora kinases may be valuable targets for potential therapeutic agents against EBV-associated carcinoma.