Cooperative treatment effectiveness of ATR and HSP90 inhibition in Ewing’s sarcoma cells

Abstract

Introduction Ewing's sarcoma is an aggressive childhood malignancy whose outcome has not substantially improved over the last two decades. In this study, combination treatments of the HSP90 inhibitor AUY922 with either the ATR inhibitor VE821 or the ATM inhibitor KU55933 were investigated for their effectiveness in Ewing's sarcoma cells. Methods Effects were determined in p53 wild-type and p53 null Ewing's sarcoma cell lines by flow cytometric analyses of cell death, mitochondrial depolarization and cell-cycle distribution as well as fluorescence and transmission electron microscopy. They were molecularly characterized by gene and protein expression profiling, and by quantitative whole proteome analysis. Results AUY922 alone induced DNA damage, apoptosis and ER stress, while reducing the abundance of DNA repair proteins. The combination of AUY922 with VE821 led to strong apoptosis induction independent of the cellular p53 status, yet based on different molecular mechanisms. p53 wild-type cells activated pro-apoptotic gene transcription and underwent mitochondria-mediated apoptosis, while p53 null cells accumulated higher levels of DNA damage, ER stress and autophagy, eventually leading to apoptosis. Impaired PI3K/AKT/mTOR signaling further contributed to the antineoplastic combination effects of AUY922 and VE821. In contrast, the combination of AUY922 with KU55933 did not produce a cooperative effect. Conclusion Our study reveals that HSP90 and ATR inhibitor combination treatment may be an effective therapeutic approach for Ewing's sarcoma irrespective of the p53 status.

Recent Advances in Synergistic Antitumor Effects Exploited from the Inhibition of Ataxia Telangiectasia and RAD3-Related Protein Kinase (ATR)

“…There are a number of HSP inhibitors in clinical stages for potential cancer treatment. The SL effects between HSP90 inhibitor AUY922 and VE-821 were reported recently in Ewing's sarcoma (ES) cells [74]. These results might provide support for further evaluation of the HSP90 inhibitor-ATRi combination in clinics.…”

Cellular senescence in cancer: molecular mechanisms and therapeutic targets

“… 93 Caffeine‐induced ATR inhibition had the opposite effect and resulted in increased S‐phase H2A.X following UV damage while having no impact on the number of focus‐positive cells, or foci per cell. Contrarily, the ATM inhibitor KU55933 and a JNK inhibitor both block S‐phase H2A.X after UV damage, 94 indicating that the kinases most likely in charge of H2A.X production after UV insult during S phase do not include ATR, but rather ATM and JNK1.…”

Synergistic anticancer activity of combined ATR and ribonucleotide reductase inhibition in Ewing's sarcoma cells

“…In an ongoing effort to systematically assess novel antineoplastic drugs, in particular novel drug combinations, for their potential as ES therapeutics, we found inhibitors of class I/II histone deacetylases (Sonnemann et al 2007) as well as modulators of sirtuins (Sonnemann et al 2016;Marx et al 2018), activators of wild-type p53 (Sonnemann et al 2011) and inhibitors of polo-like kinase 4 (Kerschner-Morales et al 2020) to be effective against ES in vitro. We have recently extended this effort to ATR inhibitors (ATRi), aiming at exploiting the replication stress response as a potential treatment regimen for ES (Marx et al 2021).…”

“…ATR kinase is a key mediator of the response to replication stress (Saxena and Zou 2022;da Costa et al 2023;Cybulla and Vindigni 2023), and as such, has attracted much interest as therapeutically exploitable target (Lecona and Fernandez-Capetillo 2018;Bradbury et al 2020;Cleary et al 2020). As to ES, ATRi were shown to be effective as single drugs (Nieto-Soler et al 2016) and to be synergistic with the WEE1 inhibitor adavosertib or the HSP90 inhibitor AUY922 (Koppenhafer et al 2020;Marx et al 2021). The ribonucleotide reductase (RNR) is another viable target for the treatment of cancer, as indicated by results from a number of clinical trials (Mannargudi and Deb 2017).…”