Figure 1.

Metformin inhibits OSCC cell proliferation and colony formation. (A) 5 × 10⁴ cells/well human OSCC cells (CAL27, WSU-HN6, and SCC25) were plated onto 12-well plates and incubated at 37°C with 5% CO₂. After 24 h, the culture medium was replaced with fresh culture medium containing 0 mM, 5 mM, 10 mM or 20 mM metformin for different time. Cell numbers were determined using a hemocytometer at each indicated time point. (B) Human OSCC cells (CAL27, WSU-HN6, and SCC25) were grown in 6-well plates (1000 cells/well). After 24 h, the culture medium was replaced with fresh culture medium containing 0 mM, 5 mM, 10 mM or 20 mM metformin every 3 days for 3 weeks. Cell colonies were stained and counted as described in the Methods section. Data are representative of three independent experiments.