Cytokine and hormone modulation of HLA-DR molecules in breast carcinoma cell lines

Abstract

Cytokines and steroidal hormones modulate HLA-DR expression on breast cancer cell lines (BCCL). This study compared the individual and combined quantitative effects of IFN-γ, IL-4, TGF-β1, and 17β-estradiol on HLA-DR expression on 8 human breast carcinoma cell lines (MCF-7, T47D, BT-474, BT-20, MDA MB 157, MDA MB 231, MDA MB 468, SKBR3) through the use of monoclonal antibodies and flow cytometry and CELISA. -- Due to problems with the reconstitution solvents, we were unable to determine the effects of estradiol treatment on HLA-DR expression. However, comparison of constitutive and IFN-γ-induced HLA-DR expression in medium containing or depleted of estrogen illustrated that media components, particularly estrogen, significantly modulated HLA-DR expression on BCCL. -- We report distinct patterns in cytokine modulation of HLA-DR expression when co-cultured in estrogen-depleted media. Although IFN-γ increased HLA-DR expression on all cell lines, addition of IL-4 selectively increased HLA-DR expression on MCF-7 and SKBR3, and addition of TGF-β1 selectively increased expression on BT-20 and SKBR3. Furthermore, analysis of TGF-β1 sensitivity through detection of phosphorylated Smad2 and Smad3 proteins (P-Smad2, P-Smad3) by Western blotting showed differential expression of P-Smad proteins in BCCL, as both BT-20 and SKBR3 expressed P-Smad3 but not P-Smad2. Since P-Smad3 is thought to inhibit CIITA in most cell types, we suggest that TGF-β1 mediated up-regulation of HLA-DR on breast cancer cell lines may be mediated through a Smad-independent pathway.