PMA withdrawal in PMA‐treated monocytic THP‐1 cells and subsequent retinoic acid stimulation, modulate induction of apoptosis and appearance of dendritic cells. (22nd May 2013)

• Record Type: Journal Article
• Authors: Spano, A.; Barni, S.; Sciola, L.
• Is Part Of: Cell proliferation. Volume 46:Number 3(2013:Jun.)
• Page Start: 328
• Page End: 347
• Publication Date: 2013-05-22
• Subjects: Cell proliferation -- Periodicals; 571.84
• DOI: 10.1111/cpr.12030
• Languages: English
• ISSNs: 0960-7722

Abstract

<abstract abstract-type="main" xml:lang="en" id="cpr12030-abs-0001"> <title>Abstract</title> <sec id="cpr12030-sec-0001" sec-type="section"> <title>Objectives</title> <p>To analyse proliferation, differentiation and apoptosis in THP‐1 cells after stimulation with phorbol 12‐myristate 13‐acetate (PMA) and retinoic acid (RA).</p> </sec> <sec id="cpr12030-sec-0002" sec-type="section"> <title>Materials and methods</title> <p>PMA and RA were used in a three‐step‐procedure: (i) treatment with 6, 30, 60 n<sc>m</sc> PMA, that induced initial, intermediate and advanced levels of monocyte‐macrophage transition, respectively; (ii) recovery in PMA‐free medium; (iii) incubation with 4 μ<sc>m</sc> RA. Cultures were characterized cytokinetically (flow cytometry/bromodeoxyuridine uptake) and immunocytochemically (static cytometry) for expression of CD14, CD11b (monocyte‐macrophage) and DC‐SIGN (dendritic cell: DCs) markers.</p> </sec> <sec id="cpr12030-sec-0003" sec-type="section"> <title>Results</title> <p>Some treatments determined appearance of monocyte/macrophage, dendritic and apoptotic phenotypes, percentages of which were related to PMA dose used in step 1, and dependent on presence/absence of PMA and RA. PMA withdrawal induced dedifferentiation and partial restoration of proliferative activity, specially in 6 and 30 n<sc>m</sc> PMA‐derived cells. Recovery in the presence of serum (fundamental to DC appearance) indicated that depending on differentiation level, cell proliferation and apoptosis were inversely correlated. Treatment with 30 n<sc>m</sc> PMA induced intermediate levels of monocytic‐macrophagic differentiation, with expression of alternative means of differentiation and acquisition of DCs without using cytokines, after PMA withdrawal and RA stimulation.</p> </sec> <sec id="cpr12030-sec-0004" sec-type="section"> <title>Conclusions</title> <p>Our experimental conditions favoured differentiation, dedifferentiation and transdifferentiational pathways, in monocytic THP‐1 cells, the balance of which could be related to both cell proliferation and cell death.</p> </sec> </abstract>