Time and dose-dependent anti-proliferative effects and inhibition of colony formation of Nar on human colorectal and breast cancer cell lines. Human colorectal cancer cells (SW1116, SW837) (A a-
e), human breast cancer cells (HTB 26, HTB132) (B a-
e) and normal human fibroblast cells (CRL1554) (A,
e) were plated (27 × 103 cells/well) in 96-well plates in CO2 and non-CO2 incubators, depending on type of media and cells, at 37°C for 18 h. The cells were then treated with various concentrations of Nar (0.05 – 4.0 mM) for 3–24 h. Cell growth was monitored using an MTT assay. Untreated and Nar-treated colorectal cancer cells SW1116 (Ca), SW837 (Cb) and Nar-treated breast cancer cells HTB26 (Cc), HTB132 (Cd) were trypsinized, counted and plated (500 cells /well) in 6-well plates. Following 10–14 days of incubation in non-CO2 incubator at 37°C, the colonies were fixed and stained with crystal violet. The stained colonies were counted and compared with the untreated control.