Interplay between EZH2/β-catenin in stemness of cisplatin-resistant HNSCC and their role as therapeutic targets

Author(s)

Milan, Thais More ; Eskenazi, Ana Patricia Espaladori ; de Oliveira, Lucas Dias ; da Silva, Gabriel ; Bighetti-Trevisan, Rayana Longo ; Freitas, Gileade Pereira ; Almeida, Luciana Oliveira

• Document type: Journal article
• Source: CELLULAR SIGNALLING; v. 109, p. 13-pg., 2023-09-01.

Abstract

The Wnt/beta-catenin signaling pathway is associated with the regulation of cancer stem cells, and it can be driven by epigenetic modifications. Here, we aim to identify epigenetic modifications involved in the control of the Wnt/beta-catenin signaling and investigate the role of this pathway in the accumulation of cancer stem cells (CSC) and chemoresistance of Head and Neck Squamous Cell Carcinoma (HNSCC). Quantitative-PCR, western blot, shRNA assay, viability assay, flow cytometry assay, spheres formation, xenograft model, and chromatin immunoprecipitation were employed to evaluate the Wnt/beta-catenin pathway and EZH2 in wild-type and chemoresistant oral carcinoma cell lines, and in the populations of CSC and non-stem cells. We demonstrated that beta-catenin and EZH2 were accumulated in cisplatin-resistant and CSC population. The upstream genes of the Wnt/beta-catenin signaling (APC and GSK3 beta) were decreased, and the downstream gene MMP7 was increased in the chemoresistant cell lines. The inhibition of beta-catenin and EZH2 combined effectively decreased the CSC population in vitro and reduced the tumor volume and CSC population in vivo. EZH2 inhibition increased APC and GSK3 beta, and the Wnt/beta-catenin inhibition reduced MMP7 levels. In contrast, EZH2 overexpression decreased APC and GSK3 beta and increased MMP7. EZH2 and beta-catenin inhibitors sensitized chemoresistant cells to cisplatin. EZH2 and H3K27me3 bounded the promoter of APC, leading to its repression. These results suggest that EZH2 regulates beta-catenin by inhibiting the upstream gene APC contributing to the accumulation of cancer stem cells and chemoresistance. Moreover, the pharmacological inhibition of the Wnt/beta-catenin combined with EZH2 can be an effective strategy for treating HNSCC. (AU)

• FAPESP's process: 20/02740-5 - Epigenetic control of WNT/b-catenin signaling in chemoresistant cancer stem cells accumulation in oral carcinoma
• Grantee: Thaís Moré Milan
• Support Opportunities: Scholarships in Brazil - Master
• FAPESP's process: 17/11780-8 - Study of epigenetic modifications related to cancer stem cells accumulation in head and neck cancer: implications in chemoresistance
• Grantee: Luciana Oliveira de Almeida
• Support Opportunities: Research Grants - Young Investigators Grants