An In Vitro Hypoxic Cancer Model Using CoCl2 on Vietnamese Breast Cancer Cells for Potential Drug Screening

Developing effective anti-cancer drugs and overcoming drug resistance continue to pose significant challenges in cancer research and clinical practice. Despite notable advancements, existing cell culture models, including advanced 3D systems, often fall short in terms of speed, scalability, and cost-effectiveness, particularly for high-throughput screening. To address these limitations, this study introduces a simple, cost-effective hypoxia model using 250 µM cobalt (II) chloride (CoCl₂) in Vietnamese breast cancer cell lines (VNBRCA1) to simulate the tumor microenvironment. The induced hypoxic conditions resulted in a significant upregulation of stemness-related genes (Nanog, Sox-4, Oct-2), autophagy-related genes (LC3-II, Beclin-1), and hypoxia-related genes (HIF-1α, HIF-2α), as confirmed by real-time quantitative PCR (RT-qPCR). Functional assays demonstrated enhanced cell migration under hypoxia, as shown by RT-qPCR and wound healing analysis, potentially involving a hybrid epithelial-mesenchymal transition (EMT) mechanism. The model’s applicability was further assessed through cisplatin treatment, revealing distinct responses under hypoxic versus normoxic conditions. These findings suggest that the CoCl₂-induced hypoxia system offers a practical approach to simulating tumor microenvironments, providing a reproducible and scalable in vitro platform for studying tumor biology and evaluating anti-cancer strategies in a more physiologically relevant context. HIGHLIGHTS A simple and cost-effective 2D hypoxia model was developed using cobalt (II) chloride (CoCl₂) in Vietnamese breast cancer cells (VNBRCA1) to mimic the tumor microenvironment. The induction of hypoxia resulted in a significant upregulation of key tumor-promoting genes associated with stemness (Nanog, Sox-4, Oct-2), autophagy (LC3-II, Beclin-1), and hypoxia markers (HIF-1α, HIF-2α), thereby more accurately reflecting the complexities of actual tumor biology. Hypoxia induced a hybrid epithelial-mesenchymal transition (EMT) phenotype and increased cell migration Cisplatin treatment revealed different drug responses under normoxic versus hypoxic conditions, highlighting the model’s relevance in studies of drug resistance. GRAPHICAL ABSTRACT