Search

Objective: Cervical cancer results from persistent infection with high-risk human papillomavirus (HR-HPV) and the expression of E6 and E7 oncoproteins. E6 and E7 compromise the activity of p53 and Rb, the G1-S cell cycle checkpoint, and ATM-mediated DNA damage repair (DDR), which in turn increases reliance on ATR- and PARP-mediated DDR at the G2 cell cycle checkpoint. This study aimed to determine the effects of an ATR inhibitor (ATRi, AZD6738) and a PARP-inhibitor (PARPi, AZD2281) on HR-HPV+ cervical cancer cell lines., Methods: The effects of ATRi and PARPi, alone and in combination, on metabolic viability, cell cycle arrest, apoptosis, and DDR pathways in cervical cancer cell lines were evaluated in vitro, and the in vivo tumor response was evaluated using a xenograft model., Results: Cervical cancer cells were sensitive to ATRi and PARPi monotherapy. The combination therapy was only synergistic in reducing metabolic viability when exposed to ATRi first, followed by PARPi, owing to ATRi-mediated upregulation of PARP expression. Combination of ATRi and PARPi induced G2 cell cycle arrest and apoptosis. PARPi induced DNA damage and γH2AX phosphorylation, which was further increased by ATRi treatment. However, PARPi-induced Rad51 foci formation was reduced by ATRi treatment, suggesting the inhibition of homologous recombination repair. ATRi significantly reduced cervical cancer xenograft tumor growth and was not affected by simultaneous PARPi treatment at the doses studied., Conclusions: Our findings show that ATRi increased reliance on PARP for metabolic viability, the combination of ATRi and PARPi induced synthetic lethality in cervical cancer in vitro, and reduced tumor burden in vivo., Competing Interests: Declaration of competing interest Author K.M.M serves on the American Board of Obstetrics and Gynecology, and is a member of the NRG Oncology Cervix and Diversity Equity and Inclusion committees. The remaining authors declare that they have no conflict of interest., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Advanced-stage endometrial cancer patients typically receive a combination of platinum and paclitaxel chemotherapy. However, limited treatment options are available for those with recurrent disease, and there is a need to identify alternative treatment options for the advanced setting. Our goal was to evaluate the pre-clinical efficacy and mechanism of action of Oklahoma Nitrone 007 (OKN-007) alone and in combination with carboplatin and paclitaxel in endometrial cancer. The effect of OKN-007 on the metabolic viability of endometrial cancer cells in both two- and three-dimensional (2D and 3D) cultures, as well as on clonogenic growth, in vitro was assessed. We also evaluated OKN-007 in vivo using an intraperitoneal xenograft model and targeted gene expression profiling to determine the molecular mechanism and gene expression programs altered by OKN-007. Our results showed that endometrial cancer cells were generally sensitive to OKN-007 in both 2D and 3D cultures. OKN-007 displayed a reduction in 3D spheroid and clonogenic growth. Subsequent targeted gene expression profiling revealed that OKN-007 significantly downregulated the immunosuppressive and immunometabolic enzyme indolamine 2,3-dioxygenase 1 (IDO1) (-11.27-fold change) and modulated upstream inflammatory pathways that regulate IDO1 expression (interferon- (IFN-), Jak-STAT, TGF-β, and NF-kB), downstream IDO1 effector pathways (mTOR and aryl hydrocarbon receptor (AhR)) and altered T-cell co-signaling pathways. OKN-007 treatment reduced IDO1, SULF2, and TGF-β protein expression in vivo, and inhibited TGF-β, NF-kB, and AhR- receptor-mediated nuclear signaling in vitro. These findings indicate that OKN-007 surmounts pro-inflammatory, immunosuppressive, and pro-tumorigenic pathways and is a promising approach for the effective treat endometrial cancer. Significance Statement Women with advanced and recurrent endometrial cancer have limited therapeutic options. OKN-007, which has minimal toxicity and is currently being evaluated in early-phase clinical trials for the treatment of cancer, is a potential new strategy for the treatment of endometrial cancer., (© 2024 The Authors. This is an open access article under the terms of the Creative Commons Attribution Non-Commercial License, which permits use, distribution, and reproduction in any medium, provided that the original work is properly cited and is not used for commercial purposes.)