Interferon-alpha promotes the anti-proliferative effect of Erlotinib (OSI-774) on human colon cancer cell lines

Interferon-alpha (IFNα) treatment is associated with up-regulation of epidermal growth factor receptor (HER1/EGFR) expression and marked growth inhibition while maintaining the sensitivity of the target colon cancer cells to epidermal growth factor (Gut 2004;53:123). We aimed to determine the effect of combining IFNα and Erlotinib (an HER1/EGFR inhibitor) on colon cancer cell line growth. Crystal-violet staining and flow cytometry were used to assess cell proliferation and expression of HER1/EGFR. IFNα pre-treatment followed by a combination of IFNα plus Erlotinib significantly enhanced the sensitivity of 7/9 of colon cancer cell lines by 7-43%. This approach may have clinical implications for improving treatment based on targeting of HER1/EGFR.