Expression of SOCS genes in normal and leukemic human leukocytes stimulated by prolactin, growth hormone and cytokines

To evaluate the possible role of the recently described family of suppresso rs of cytokine signaling (SOCS) factors in the human lympho-hemopoietic sys tem, we have monitored SOCS factor expression, both constitutive and induce d by either cytokines, prolactin (PRL) or growth hormone (GH), using polyme rase chain reaction in normal and leukemic cells, CIS (cytokine-inducible S H2-containing protein), SOCS-2 and SOCS-3 were constitutively expressed in peripheral blood mononuclear leukocytes. SOCS-3 expression was enhanced by PRL or by IFN-gamma. In bone marrow cells and granulocytes, CIS expression was induced and SOCS-2 enhanced by IFN-I and by PRL. In tonsillar cells. CI S expression was increased and SOCS-2 was induced by IL-1 beta, IL-6, PRL a nd GH. SOCS-3 expression was enhanced by IL-IP. The expression of SOCS-7 wa s increased by IL-6, PRL and GH. In Raji B-lymphoma cells, the expression o f SOCS-2 and SOCS-7 was enhanced by IL-IP. In THP-I myeloid leukemia cells pretreated with TPA (to induce receptors for IFN-gamma), IFN-gamma induced SOCS-2. Jurkat cells expressed more SOCS-2 when exposed to PRL. Original ob servations in this work include the first report on SOCS-7 induction by cyt okines. Also our data shed new light on the possible involvement of PRL and GN in the cytokine network. These hormones could modulate the transduction of signals originating from receptors for various cytokines. (C) 2000 Else vier Science BN. All rights reserved.