Indeed, combination of intratumor injections of mouse IFN-α and intraperitoneal injections of anti-CD137 mAb synergized as seen on subcutaneous lesions derived from the MC38 colon carcinoma, which is resistant to each treatment if given separately.
We demonstrated that colon cancer cell lines with Ki-ras mutations display reduced expression of IFN-responsive genes compared with the cell lines that have retained wild type Ras and that inactivation of the mutant Ki-ras allele in the HCT116 colon cancer cell line is sufficient to restore the expression of STAT1, STAT2, and IRF-9.
These results indicated that IFN-inducible gene family 1-8U expression in inflamed colonic mucosa might be used as a preferential marker of colitis-associated colon cancer in UC.
Therefore, we examined the ability of a retrovirus-mediated IFN-alpha gene transfer to infect colon cancer cells COLO 201 and the effect of IFN-alpha gene expression alone or in combination with other chemotherapeutic drugs as 5-FU.
Treatment of two human colon cancer cell lines (HT-29 and WiDr) with 5-FU + gamma-IFN resulted in an increase of CEA expression higher than that obtainable with both agents alone, although no synergistic effects were obtained.