Differences in the state of differentiation of THP-1 cells induced by phorbol ester and 1,25-dihydroxyvitamin D3

Abstract

Human THP-1 leukemia cells differentiate along the monocytic lineage following exposure to phorbol-12-myristate-13-acetate (PMA) or 1,25-dihydroxyvitamin D3 (VD3). In the monocytic cell line THP-1, PMA treatment resulted in a more differentiated phenotype than VD3, according to adherence, loss of proliferation, phagocytosis of latex beads, and expression of CD11b and CD14. Both differentiating substances induced similar effects in the release of superoxide anions (O2-). VD3-differentiated cells did not release prostaglandin E2 (PGE2), in contrast to PMA-differentiated cells, and in PMA-differentiated cells phospholipase A2 (PLA2) activity and expression was increase. Lipopolysaccharide (LPS)-stimulated tumor necrosis factor-alpha (TNF-alpha) release was higher in PMA-treated cells. PMA- but not VD3-differentiation resulted in a translocation of protein kinase C (PKC) isoenzymes to membrane fractions. Both differentiating agents up-regulated the expression of PKC isoenzymes. Whereas VD3 elevated mainly the expression of PKC-beta, PMA caused a strong increase in PKC-delta and a weak increase in PKC-alpha, PKC-epsilon, and PKC-zeta expression. These results indicate that phorbol ester and the active metabolite of vitamin D induce different signal pathways, which might result in different achievement of differentiation.

The Shaving Reaction: Rituximab/CD20 Complexes Are Removed from Mantle Cell Lymphoma and Chronic Lymphocytic Leukemia Cells by THP-1 Monocytes

“…We have now investigated loss of CD20 from B cells in an in vitro model system, using THP-1 monocytes as effector cells (35)(36)(37). Binding of RTX to several CD20 ϩ cell lines or to freshly isolated B cells from CLL patients leads, in the presence of THP-1 cells, to rapid and substantial loss of RTX and CD20 from the B cell surface.…”

“…Cells were washed with cold BSA/PBS before incubation with THP-1 cells. Two to 3 days before an experiment, THP-1 cells were treated with 1 M PMA to induce differentiation (36,37,44) and were plated in 24-well plates, 10 6 cells/well, in 1 ml (BD Biosciences). In some experiments, adherent THP-1 cells were labeled with PKH 26 (see below) before addition of RTX-opsonized donor cells.…”

“…To study the shaving reaction, we used as acceptor cells the human monocytic cell line THP-1, differentiated to a more macrophage-like phenotype by treatment with PMA (35)(36)(37). RTXopsonized, CD20 ϩ cells were either: 1) held on ice (control 1); 2) incubated alone at 37°C for 45 min (control 2); 3) added to THP-1 cells and immediately quenched with cold BSA-PBS (control 3, zero time); or 4) incubated with THP-1 cells at 37°C for 45 min to induce shaving (shaving sample, see Fig.…”

“…THP-1 cells can also be induced to undergo differentiation into a more macrophage-like state by treatment with retinoic acid (36,37,44), and, as illustrated in Table I, Expt. 3, THP-1 cells promoted comparable levels of shaving of RTX-opsonized Raji cells after differentiation with either PMA or retinoic acid.…”

Modulation of P2X7 nucleotide receptor expression by pro- and anti-inflammatory stimuli in THP-1 monocytes

“…Several indices of macrophage differentiation can also be induced when THP-1 cells are cultured with phorbol esters. However, the THP-1 phenotypes induced by phorbol esters versus inflammatory cytokines varies with respect to secretion of soluble mediators, cytokines, and eicosanoids [24,25]. We examined the ability of phorbol 12-myristate 13-acetate (PMA; 100 nM) to induce BzATP-stimulated pore formation.…”