Author(s): Pádua, Diana ; Barros, Rita ; Amaral, Ana Luísa ; Mesquita, Patrícia ; Freire, Ana Filipa ; Sousa, Mafalda ; Maia, André Filipe ; Caiado, Inês ; Fernandes, Hugo ; Pombinho, António ; Pereira, Carlos Filipe ; Almeida, Raquel
Date: 2020
Persistent ID: https://hdl.handle.net/10316/105848
Origin: Estudo Geral - Universidade de Coimbra
Subject(s): cancer stem cells; gastric cancer; SOX2; monensin; SORE6-GFP reporter system; drug resistance; high-throughput screening
Gastric cancer remains a serious health burden with few therapeutic options. Therefore, the recognition of cancer stem cells (CSCs) as seeds of the tumorigenic process makes them a prime therapeutic target. Knowing that the transcription factors SOX2 and OCT4 promote stemness, our approach was to isolate stem-like cells in human gastric cancer cell lines using a traceable reporter system based on SOX2/OCT4 activity (SORE6-GFP). Cells transduced with the SORE6-GFP reporter system were sorted into SORE6+ and SORE6- cell populations, and their biological behavior characterized. SORE6+ cells were enriched for SOX2 and exhibited CSC features, including a greater ability to proliferate and form gastrospheres in non-adherent conditions, a larger in vivo tumor initiating capability, and increased resistance to 5-fluorouracil (5-FU) treatment. The overexpression and knockdown of SOX2 revealed a crucial role of SOX2 in cell proliferation and drug resistance. By combining the reporter system with a high-throughput screening of pharmacologically active small molecules we identified monensin, an ionophore antibiotic, displaying selective toxicity to SORE6+ cells. The ability of SORE6-GFP reporter system to recognize cancer stem-like cells facilitates our understanding of gastric CSC biology and serves as a platform for the identification of powerful therapeutics for targeting gastric CSCs.
