Modulation of mucin synthesis by gamma-interferon in human colon adenocarcinoma cells

Recombinant human interferon has been shown to enhance the expression of histocompatibility antigens and certain tumor-associated antigens in a variety of carcinoma cell lines. Since many tumor-associated antigens are mucins, we investigated the effect of recombinant human gamma-interferon on mucin production and secretion by colon cancer cell lines.

Control and gamma-interferon-treated cells were labeled with [(3)H]glucosamine in DMEM-H16 medium with 5% FCS for 24 h. Analysis was performed by gel filtration on Sepharose CL-4B columns, and the high-molecular-weight glycoprotein eluted at the void volume from the cytosol and medium was counted (expressed as dpm/4 x 10(6) cells). In another experiment the void volume was compared to concentration curves of standard mucins (expressed as mg/10(7) cells).

gamma-Interferon increased mucin synthesis in HT-29 and LIM-6 cells, but not in LS174T and CACO2 cells. In HT-29 and LIM-6 cells, mucin synthesis was induced by gamma-interferon in a dose-dependent manner. The percentage of mucin secreted into the medium was also increased.

The heterogeneity of response of human colon cancer cell lines to gamma-interferon by mucin production may limit the specific role of gamma-interferon as a modulator of mucin-type tumor-associated antigens.