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Objective: Although there is a large amount of data on the role of preadipocytes in promoting the release of proinflammatory cytokines and chemokines in response to macrophage-derived cytokines, the direct role of insulin and saturated fatty acids in modulating the release of inflammatory cytokines by cells differentiating along the adipocytic lineage is less understood. Methods: 3T3-L1 murine preadipocyte cells were cultured for 3 d in a proliferating medium in the presence or absence of insulin 0.2 nmol/L plus palmitic acid 1 mmol/L. In parallel, 3T3-L1 cells were cultured in a differentiation medium containing dexamethasone, insulin, and isobutyl methyl xanthine in the absence or presence of palmitic acid for 3 d. The levels of several cytokines were evaluated in the culture supernatants by a bead-based multiplex immunoassay. Results: Under the proliferation conditions, insulin plus palmitic acid promoted a significant increase in the release of interleukin-6, keratinocyte-derived chemokine (KC)/chemokine ligand-1 (CXCL-1), monocyte chemotactic protein-1 (MCP-1), and regulated and normal T cells expressed and presumably secreted (RANTES) by 3T3-L1 preadipocytes. Of note, the release of KC/CXCL-1, MCP-1, and RANTES increased significantly with adipocytic differentiation, and the addition of palmitic acid to differentiating 3T3-L1 cells resulted in a further significant promotion of KC/CXCL1, MCP-1, and RANTES, coupled to the increase of additional cytokines. Conclusions: Taken together, these data show that a restricted common group of cytokines/chemokines (KC/CXCL1, MCP-1, and RANTES) is upregulated in proliferating and differentiating 3T3-L1 adipocytes in response to insulin and palmitic acid and that differentiating adipocytes respond with an increased range of cytokines with respect to proliferating 3T3-L1 preadipocytes. [ABSTRACT FROM AUTHOR]

The small-molecule inhibitor of murine double minute (MDM-2), Nutlin-3, induced variable apoptosis in primary acute myeloid leukemia (AML) blasts and promoted myeloid maturation of surviving cells, as demonstrated by analysis of CD11b and CD14 surface antigens and by morphologic examination. Although the best-characterized activity of Nutlin-3 is activation of the p53 pathway, Nutlin-3 induced maturation also in one AML sample characterized by p53 deletion, as well as in the p53-/- human myeloblastic HL-60 cell line. At the molecular level, the maturational activity of Nutlin-3 in HL-60 cells was accompanied by the induction of E2F1 transcription factor, and it was significantly counteracted by specific gene knockdown with small interfering RNA for E2F1. Moreover, Nutlin-3, as well as tumor necrosis factor (TNF) α, potentiated the maturational activity of recombinant TNF-related apoptosis-inducing ligand (TRAIL) in HL-60 cells. However, although TNF-α significantly counteracted the proapoptotic activity of TRAIL, Nutlin-3 did not interfere with the proapoptotic activity of TRAIL. Taken together, these data disclose a novel, potentially relevant therapeutic role for Nutlin-3 in the treatment of both p53 wild-type and p53-/- AML, possibly in association with recombinant TRAIL. [ABSTRACT FROM AUTHOR]