FK506 and cyclosporin A inhibit stem cell factor-dependent cell proliferation/survival, while inducing upregulation of c-kit expression in cells of the mast cell line MC/9

Abstract

Murine mast cell proliferation and maturation are regulated by two distinct cytokines, interleukin-3 (IL-3) and the c-kit ligand, stem cell factor (SCF). In this study using cells of the mouse mast cell line, MC/9, the effects of two immunosuppressants, FK506 and cyclosporin A (CsA), were investigated. Withdrawal of IL-3 from the culture medium resulted in loss of viability of MC/9 cells. The addition of SCF in the absence of IL-3 maintained MC/9 cell survival but no cell proliferation was detected. The combined addition of IL-3 and SCF to the culture medium resulted in a more marked MC/9 cell proliferation than the addition of IL-3 alone. FK506 and CsA inhibited the SCF-dependent, but not the IL-3 dependent, stimulatory effects on MC/9 cell proliferation/survival. Apoptotic changes were analyzed using fluorescent staining with acridine orange and DNA electrophoresis. FK506 and CsA inhibited the SCF-dependent rescue effect from apoptosis. Flow cytometry showed that FK506 and CsA did not affect IL-3 receptor expression. However, immunoblot and reverse transcriptase-polymerase chain reaction (RT-PCR) analyses indicated that c-kit protein and c-kit mRNA transcripts were increased following the FK506 and CsA treatments in the presence of IL-3. In addition, MC/9 cells pretreated with FK506 or CsA showed an increased adhesiveness to NIH/3T3 cells that express membrane-bound SCF. Neither FK506 nor CsA affected c-kit tyrosine phosphorylation or MAP kinase nuclear translocation of MC/9 cells following SCF stimulation. These results indicate that FK506 and CsA, while inducing c-kit of MC/9 cells, selectively inhibit the SCF-dependent stimulatory effects on MC/9 cell proliferation/survival by a mechanism independent of, or at point(s) distal to, the c-kit-MAP kinase pathway.

Histological Study on Mast Cells in Conjunctiva of NC/Nga Mice

“…FK506 also has suppressive effects on the proliferation of mast cells through the c-kit-MAP kinase pathway. 19 These observations suggest that corticosteroids and FK506 may have a direct effect on mast cells in human conjunctival tissue. In this study, in comparison with mast cell density in the 16W-group, mast cell density in the Dx group was decreased, but in the FK506 group, there was no significant change.…”

Mast Cells as Targets of Pimecrolimus

“…Tacrolimus and CsA were found to inhibit the SCF dependent, but not the IL-3 dependent stimulatory effects on MC/9 cell proliferation/survival through inducing apoptosis directly. However, SCFmediated signal transduction in MC/9 cells, including c-Kit tyrosine phosphorylation and MAP kinase nuclear translocation, were not affected by tacrolimus or CsA treatment [30]. Concluded, calcineurin inhibitors can selectively inhibit SCF-dependent mast cell proliferation/survival and induce mast cell apoptosis, but only some of the SCF-mediated signaling pathways were affected by these drugs.…”

“…the numbers of mast cells in the above mentioned diseases or disease models, which is in discordance with their effects in mastocytosis. We propose the hypothesis that the observed effects may be explained by differential effects of calcineurin inhibitors hyperproliferative mast cells induced by SCF [30] but not act on the hyperactive mast cells induced by the allergens. Future scaled-up clinical studies should verify, whether the above hypothesis is correct or not.…”

“…Tacrolimus and CsA were found to inhibit directly the SCF dependent proliferation and survival of cultured mast cells through the in vitro induction of apoptosis [30]. SCF binds to its receptor, cKit, and stimulates the differentiation and proliferation of mast cells from CD34 + cells.…”

Stem Cell Factor and Thymic Stromal Lymphopoietin Overexpression With Correlation to Mast Cells in Superior Limbic Keratoconjunctivitis

“…In addition to being a T-cell immunosuppressive agent, cyclosporine has also been shown to block mast cell proliferation and inhibit histamine release from mast cells. 12,13 Confino and Brown 8 in 1987 reported that 6 of 8 patients with SLK showed marked improvement or complete resolution with topical cromolyn sodium 4% therapy. In 1995, Grutzmacher et al 9 reported 3 cases with typical SLK presentation.…”