Failure of cyclosporin A to induce transforming growth factor beta (TGF-beta) synthesis in activated peripheral blood lymphocytes

Cyclosporine-A induces apoptosis in human prostate cancer cells PC3 and DU145 via downregulation of COX-2 and upregulation of TGFβ

Background

Potential targets for prostate cancer therapy are urgently needed for curative of patients. Cyclosporine-A (CsA), an immunosuppressive and a selective cyclooxygenase-2 (COX-2) inhibitor, exerts antitumor activity. However, the molecular effects of CsA is not fully understood in prostate cancer. In this research, we sought to determine role and mechanism of CsA in prostate cancer.

Materials and methods

PC3 and DU145 cells were treated with CsA time (12, 24, 48 h) and dose dependent (2.5, 10, 25 μM) and cell survival, migration, colony formation, expression of apoptosis related proteins/genes using MTT assay, scratch assay, Western blotting/qPCR. At the same time, cells treated with CsA to test on the effects of COX-2 promoter activity using luciferase reporter plasmid. Lastly, functional role in the CsA treatment prostate cancer cells were interrogated for relationship of TGFβ, Akt, caspases and COX-2.

Results

These study findings provided direct evidences that the CsA induced apoptosis and downregulated migration.

Conclusions

CsA downregulated Akt as well as COX-2 and upregulated TGFβ, resulting in the suppression of cell migration which was augmented a potential therapeutic of CsA in prostate cancer cells.

Regulation of the NFAT pathway discriminates CD4+CD25+ regulatory T cells from CD4+CD25- helper T cells

CD4(+)CD25(+) regulatory T cells (Tregs) are potent modulators of immune responses. The transcriptional program distinguishing Tregs from the CD4(+)CD25(-) Th cells is unclear. NFAT, a key transcription factor, is reported to interact with forkhead box p3, allowing inhibitory and activating signals in T cells. In the current study, we hypothesize that distinctive NFAT regulation in Tregs as compared with Th cells, may contribute to specific functions of these cells. Tregs express basal levels of cytoplasmic NFATc1 and NFATc2. In contrast to Th cells, anti-CD3-mediated T cell activation did not induce nuclear translocation of NFATc1 or NFATc2 in Tregs. This effect was associated with altered regulation for NFAT in Tregs that included reduced calcium flux, diminished calcineurin activation, and increased activity of glycogen synthase kinase-3beta, a negative regulatory kinase for NFAT in Tregs relative to Th cells. These data suggested that NFAT inhibition in Th cells may induce regulatory function. Indeed, pharmacologically mediated NFAT inhibition induced Th cells to function as Tregs, an effect that was mediated by induction of membrane-bound TGF-beta on Th cells. Collectively, these data suggest that maintaining NFAT at basal levels is a part of the transcriptional program required for Tregs.

Cyclosporin-A inhibits the expression of cyclooxygenase-2 in gingiva

BACKGROUND AND OBJECTIVE

Various inflammatory mediators are involved in the development of cyclosporine A-induced gingival overgrowth. In this study, the gingival expression of cyclooxygenase-2 after cyclosporine A therapy was examined in vivo and in vitro.

MATERIAL AND METHODS

After edentulous ridges on maxilla were established, 21 Sprague-Dawley rats received cyclosporine A daily for 4 wk, and a further 21 rats received solvent. After the rats were killed, the expression of cyclooxygenase-2 mRNA, interleukin-1beta mRNA, tumor necrosis factor-alpha mRNA, and interleukin-6 mRNA was examined in the edentulous gingiva. The expression of cyclooxygenase-2 protein and the production of prostaglandin E2 were also evaluated.

RESULTS

In cultured human gingival fibroblasts and epithelial cells, the expression of cyclooxygenase-2 mRNA was measured after treatment with cyclosporine A. Significantly lower expression of cyclooxygenase-2 and interleukin-1beta mRNA, but higher interleukin-6 expression, were observed in gingiva from cyclosporine A-treated rats than in those from the control rats. Significantly less prostaglandin E2 production was observed in cyclosporine A-treated rats. Immunohistochemistry revealed that fewer gingival stromal cells were positively stained for cyclooxygenase-2 in cyclosporine A-treated rats. In cultured cells, significantly less cyclooxygenase-2 mRNA was detected after treatment with cyclosporine A.

CONCLUSION

The expression of cyclooxygenase-2 was lower in the plaque nonretentive gingivae and the in vitro gingival cells upon treatment with cyclosporine A. Thus, we propose that cyclosporine A inhibits the expression of gingival cyclooxygenase-2.

Expression of cyclooxygenase-1 and cyclooxygenase-2 in human renal allograft rejection - a prospective study

Cyclooxygenases (COX) are known to be involved in inflammatory kidney diseases. However, there are no data available about the expression of COX-1 and only preliminary reports about the expression of COX-2 in biopsies of patients undergoing acute renal allograft rejection. We conducted this prospective study to analyze the expression, distribution, and cellular localization of COX-1 and -2 and thus to elucidate the role of COX in human kidney transplantation. One hundred forty-four biopsies were included from patients without rejection and unaltered morphology (n = 60), with acute interstitial rejection (n = 7), with acute vascular rejection (n = 21), with chronic allograft nephropathy (n = 16), without rejection but with various other lesions (n = 40). COX-1 and -2 expression was localized in each biopsy by immunohistochemistry. We found a highly significant up-regulation of COX-1 in vessels and in infiltrating interstitial cells of patients with acute allograft rejection compared with biopsies with well-preserved tissue. Also, COX-2 expression was significantly elevated in infiltrating interstitial cells of biopsies with acute rejection. This is the first prospective study demonstrating a significant induction of both COX-1 and -2 in human allograft biopsies with acute rejection after renal transplantation.

Modulation of COX-2 expression in peripheral blood cells by increased intake of fruit and vegetables?

BACKGROUND

Enhanced cyclooxygenase-2 (COX-2) expression is associated with carcinogenesis, ischemia, angiogenesis, inflammation, and neurodegeneration. The preventing effect of aspirin and nonsteroidal anti-inflammatory drugs is partly due to inhibition of the COX-2 enzyme. Fruit and vegetables (FVs) contain numerous compounds that may decrease disease risk by several different mechanisms, for example through the inhibition of COX-2 activity.

OBJECTIVE

We tested the hypothesis that an increased intake of FVs would modulate the COX-2 expression in peripheral blood cells.

DESIGN

A strictly controlled dietary crossover study (n = 39). After 1 week run-in period with no FVs in the diet, one group was given two portions of FVs (2 FV), while another group was given five portions (5 FV) daily for 14 days. Following a 2 weeks washout period and 1 week run-in, the regimens were switched between the groups. Gene expression analysis of COX-2 mRNA in blood samples was performed by quantitative real-time-PCR.

RESULTS

No significant treatment effect of diet intervention was found in the crossover analyses (P = 0.74). However, the individual variation in response may seem large.

CONCLUSIONS

These data does not contradict the recommendations for an increased intake of FVs. Further studies on expression directly and indirectly, through analysis of factors regulating and being regulated by COX-2, should be carried out. A first step would be to evaluate the correspondence between COX-2 mRNA expression and products of the COX pathway, like prostaglandins. Naturally occurring polymorphisms of COX-2 promoters and coding regions might contribute to functional variations and response to different diets.

SPONSORSHIP

Norwegian Research Council, National Nutrition Council, Throne Holst Foundation for Nutrition Research, Freia Chokoladefabriks Medisinske Fond and the Norwegian Cancer Society.

Concentrations of cyclosporin A and FK506 that inhibit IL-2 induction in human T cells do not affect TGF-beta1 biosynthesis, whereas higher doses of cyclosporin A trigger apoptosis and release of preformed TGF-beta1

Cyclosporin A (CsA) and FK506 suppress T cell activation by inhibiting calcineurin and the calcineurin-dependent transcription factors nuclear factor of activated T cells (NFATc), which are central regulators of T cell function. It was reported that CsA up-regulated the transcription of transforming growth factor-beta1 (TGF-beta1) in lymphocytes and other cells and activated its promoter in A549 lung carcinoma cells, but the mechanisms involved are poorly understood, and it is unclear whether calcineurin plays any role. We have studied the regulation of TGF-beta1 in normal human lymphocytes and cell lines. In Jurkat T cells, the TGF-beta1 promoter was activated by calcineurin and NFATc and inhibited by CsA and FK506. However, the promoter was insensitive to both drugs in A549 cells. In human T cells preactivated with phytohemagglutinin, biosynthesis of TGF-beta1, induced by the T cell receptor (TCR) or the TGF-beta receptor, was not substantially affected by CsA and FK506 concentrations (< or = 1 microM) that effectively inhibited interleukin-2 production. However, pretreatment of fresh lymphocytes with CsA or FK506 during primary TCR stimulation reduced their production of TGF-beta1 during secondary TCR activation. Finally, high concentrations of CsA (10 microM), in the range attained in vivo in experiments in rodents, caused apoptosis in human T cells and the release of preformed, bioactive TGF-beta1. These effects are unlikely to owe to calcineurin inhibition, as they were not observed with FK506. Our results indicate that CsA and FK506 are not general inducers of TGF-beta1 biosynthesis but can cause different effects on TGF-beta1 depending on the cell type and concentrations used.

Differential effects of rapamycin, cyclosporine A, and FK506 on human coronary artery smooth muscle cell proliferation and signalling

BACKGROUND

Immunosuppressive agents are at the forefront of preventing organ rejection after transplantation. However, their effects on vascular smooth muscle cell-mediated intimal hyperplasia that occurs in post-transplant coronary artery disease are less well known.

METHODS AND RESULTS

We investigated the in vitro effects of three immunosuppressive agents cyclosporine A (CsA), FK506 (tacrolimus), and rapamycin (sirolimus, Rapa) on cultured human coronary artery smooth muscle cells (cSMC). CsA inhibited both platelet-derived growth factor (PDGF)-stimulated DNA synthesis and serum-induced proliferation at high concentrations (> or =1000 ng/ml). The growth-inhibitory effect of CsA was not altered by anti-TGF-beta neutralising antibodies nor was autocrine TGF-beta release detected in CsA-treated culture medium. At inhibitory doses, CsA inhibited ERK kinase activation by PDGF, although cytotoxicity was also apparent. Most notably, CsA visibly prevented PDGF-induced altered cell morphology. Rapa was a highly potent and effective inhibitor of cSMC proliferation (reduction in DNA synthesis by >50% from 0.01 ng/ml), acting through inhibition of 70-kDa S6 kinase (p70S6k). FK506 (1-1000 ng/ml) did not affect cSMC proliferation alone, although a > or =250-fold excess of FK506 over Rapa completely reversed the inhibitory effect of Rapa, confirming that these two agents share a common intracellular receptor, the FK506-binding protein (FKBP).

CONCLUSION

Rapa is a powerful inhibitor of cSMC proliferation, while CsA slighly inhibits cSMC proliferation, although only at higher concentrations that may be toxic. These results indicate that therapeutic immunosuppression with Rapa may be additionally useful in prevention or delay of posttransplant coronary artery disease.

Expression of cyclooxygenase-2 in biopsies obtained from human transplanted kidneys undergoing rejection

BACKGROUND

The inducible cyclooxygenase (COX)-2 is a target of immunosuppressive drugs routinely administered to patients after transplantation. This study investigates a potential involvement of COX-2 in transplant rejection. Therefore, we examined the expression of COX-2 in biopsies obtained for diagnostic purposes.

METHODS

COX-2 was detected by immunohistochemistry and in situ hybridization. Congruent staining was obtained by both methods: in specimens of a kidney explanted as the result of vascular rejection, tubular epithelial cells and endothelial cells stained positively for COX-2. Furthermore, in appendiceal specimens obtained at surgery, epithelial cells of the crypts, interstitial cells, and mesothelial cells were positive by both methods, affirming the specificity of the antibody.

RESULTS

Compared with healthy control subjects, intensive staining of COX-2 was observed in most of the 28 biopsies obtained from patients diagnosed with vascular rejection combined with cellular interstitial rejection and tubulitis. Glomeruli and the macula densa area were essentially negative compared with prominent staining in cortical and medullary epithelial cells of the tubuli. Staining was distinct with individual positive cells in the tubular cross sections. Few arteries expressed COX-2 in intimal cells. Less prominent expression of COX-2 was detected in the biopsies of six kidneys obtained from patients diagnosed with acute tubular necrosis.

CONCLUSION

This is the first report to show the up-regulation of COX-2 in human transplanted kidneys, despite ongoing immunosuppressive treatment. It remains to be established whether the up-regulation of COX-2 is part of the rejection process or has to be considered implicated in renal preservative mechanisms.