Progesterone receptor expression by human leukocyte cell lines: molecular mechanisms of cytokine suppression.

PURPOSE

We investigated progesterone (P) signaling in human leukemia cells, shown to downregulate cytokines with P.

METHODS

The following tests were utilized: PCR with FAM labeled primers and Gene Scan with the Applied Biosystems 373 DNA sequencer for progesterone receptor (PR) mRNA, immunohistochemistry using monoclonal antibodies (Zymed and Ventana) for PR protein, RT-PCR for glucocorticoid receptor (GR), NFkappaB (p65, p50, p52), c-rel, IkappaB-alpha, c-jun, c-fos, mRNA, transient transfections with pNF-kappaB-SEAP, and pGRE-SEAP vectors with chemiluminescence detection for NFkappaB and GR activity.

RESULTS

PR transcripts were demonstrated in MOT, U937, K562, THP-1, 8226, U226, not in JUKAT, HL60, HUT102, isolated normal peripheral blood mononuclear cells, or purified CD4+ or CD8+ T cells. Estradiol increased PR mRNA in MOT and U937. MOT, U937, K562, KG-1, 8226, ATL, and CD8+HTLV-1 expressed PR protein. SRIH-BATL, 729PH6NEO, HS-1, R-CLL, and JURKAT were negative. Steady state mRNA for GR, NFkappaB (p65, p50, p52), IkappaB-alpha, c-jun were unchanged with P in MOT and U937; c-fos and c-rel were not detected. There was a concentration-dependent reduction of NFkappaB activity with P in MOT and U937.

CONCLUSION

The mechanism of cytokine suppression by P is mediated at least in part by suppression of NFkappaB, but the interaction of sex hormones, receptors, and transcription factors is complex.