In vitro increased natural killer cell activity of metastatic melanoma patients with interferon-α alone as opposed to its combination with 13-cis retinoic acid is associated with modulation of NKG2D and CD161 activating receptor expression

Riferimento: 
J BUON. 2012 Oct-Dec;17(4):761-9.
Autori: 
Konjevic G, Mirjacic-Martinovic K, Vuletic A, Babovic N.
Fonte: 
J BUON. 2012 Oct-Dec;17(4):761-9.
Anno: 
2012
Azione: 
La valorizzazione favorevole dell'attività dei natural killer (NK) nei pazienti con melanoma metastatico (MM) ottenuto con interferone (IFN)-α è associata all'attivazione dei recettori NKG2D e CD161, mentre la mancanza di acido 13-cis retinoico (RA) è associata alla espressione inibitoria del recettore CD158b.
Target: 
RA-NK-IFN/melanoma metastatico.

ABSTRACT
PURPOSE:
Considering tumor-induced suppression of natural killer (NK) cell activity the aim of this study was to investigate the in vitro effect of a standard immunotherapeutic cytokine, interferon (IFN)α, and a less investigated agent, 13-cis retinoic acid (RA) on the functional and receptor characteristics of CD16-defined NK cells and their functionally diverse dim and bright subsets in patients with metastatic melanoma (MM).
METHODS:
Peripheral blood lymphocytes (PBL) of patients with clinical stage IV MM were stimulated in vitro for 18 h in RPMI 1640 culture medium (CM) alone, CM supplemented with IFN-α (250 U7sol;ml), RA (10-6M) and their combination. NK cell activity was determined using standard 4 h radioactive cytotoxicity assay, while the expression of activating (NKG2D, CD1617rpar; and inhibitory (CD158a, CD158b) NK cell receptors on CD3-CD16+ NK cells and their functional bright and dim subsets were analyzed by flow cytometry.
RESULTS:
NK cell cytotoxic activity was increased after in vitro treatment with IFN-α alone and in combination with RA, while only IFN-α induced increase in NKG2D and CD161 activating NK cell receptor expression. Contrary to this, RA treatment increased the expression of inhibitory KIR CD158b. IFN-α-obtained increase in CD161 expression was due to its induction on both NK cell subsets, while for NKG2D only on CD16bright subset.
CONCLUSION:
The favorable enhancement of NK cell activity of MM patients obtained with IFN-α is associated with upregulation of activating NKG2D and CD161 receptors, while the lack of RA-associated upregulation is probably due to the shown increased expression of inhibitory KIR receptor CD158b after in vitro treatment with this agent.

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