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A SOX2 Reporter System Identifies Gastric Cancer Stem-Like Cells Sensitive to Monensin
Diana Pádua1,2, Rita Barros1,2,3, Ana Luísa Amaral1,2
1i3S-Institute for Research and Innovation in Health, University of Porto, 4200-135 Porto, Portugal.
Abstract:
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.
Insights
Researchers identified gastric cancer stem cells (CSCs) using a reporter system. They found SOX2 is crucial for CSC proliferation and drug resistance, and identified monensin as a potential therapeutic agent targeting these cells.
Area of Science:
- Oncology
- Stem Cell Biology
- Molecular Biology
Background:
- Gastric cancer poses a significant health challenge with limited treatment strategies.
- Cancer stem cells (CSCs) are recognized as key drivers of tumor initiation and progression.
- Transcription factors SOX2 and OCT4 are critical regulators of stemness in various cancers.
Purpose of the Study:
- To develop a traceable reporter system to isolate and characterize gastric CSCs.
- To investigate the role of SOX2 in gastric CSC biology, including proliferation and drug resistance.
- To identify novel therapeutic agents targeting gastric CSCs.
Main Methods:
- Development of a SORE6-GFP reporter system to track SOX2/OCT4 activity in human gastric cancer cell lines.
- Isolation and characterization of SORE6+ (stem-like) and SORE6- cell populations.
- High-throughput screening of small molecules to identify agents selectively toxic to SORE6+ cells.
Main Results:
- SORE6+ cells demonstrated enriched SOX2 expression and exhibited key CSC features: enhanced proliferation, sphere formation, tumor initiation, and 5-fluorouracil (5-FU) resistance.
- SOX2 manipulation (overexpression/knockdown) confirmed its essential role in proliferation and drug resistance.
- Monensin, an antibiotic, was identified as selectively toxic to SORE6+ cells.
Conclusions:
- The SORE6-GFP reporter system effectively identifies gastric CSCs.
- SOX2 is a critical determinant of gastric CSC phenotype and drug resistance.
- Monensin represents a promising therapeutic candidate for targeting gastric CSCs.
