-
[show abstract]
[hide abstract]
ABSTRACT: We have studied the functional role of protein kinase Cε (PKCε) in the control of human CD4(+) T cell proliferation and in their response to TGF-1β. We demonstrate that PKCε sustains CD4(+) T cell proliferation triggered in vitro by CD3 stimulation. Transient knockdown of PKCε expression decreases IL-2R chain transcription, and consequently cell surface expression levels of CD25. PKCε silencing in CD4 T cells potentiates the inhibitory effects of TGF-1β, whereas in contrast, the forced expression of PKCε virtually abrogates the inhibitory effects of TGF-1β. Being that PKCε is therefore implicated in the response of CD4 T cells to both CD3-mediated proliferative stimuli and TGF-1β antiproliferative signals, we studied it in Hashimoto thyroiditis (HT), a pathology characterized by abnormal lymphocyte proliferation and activation. When we analyzed CD4 T cells from HT patients, we found a significant increase of PKCε expression, accounting for their enhanced survival, proliferation, and decreased sensitivity to TGF-1β. The increased expression of PKCε in CD4(+) T cells of HT patients, which is described for the first time, to our knowledge, in this article, viewed in the perspective of the physiological role of PKCε in normal Th lymphocytes, adds knowledge to the molecular pathophysiology of HT and creates potentially new pharmacological targets for the therapy of this disease.
The Journal of Immunology 09/2011; 187(9):4721-32. · 5.79 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Sulfur is able to penetrate the skin, and a sulfur-rich balneotherapy has been suggested to be effective in the treatment of psoriasis. Psoriasis is now considered a genetically programmed, immune-mediated, inflammatory disease, in which intralesional T lymphocytes trigger keratinocytes to proliferate and perpetuate the disease process. Interleukin (IL)-17 and IL-22 produced by Th1/Th17 lymphocytes induce IL-8 secretion by keratinocytes, a key event in the pathogenesis of the disease. It is now clear that mitogen-activated protein kinase (MAPK) (extracellular signal-regulated kinases (ERK) 1 and 2) activity is required for IL-17-induced IL-8 synthesis by keratinocytes, and, in fact, MAPK activity is increased in lesional psoriatic skin. Here, we demonstrate both in vitro and in vivo on primary psoriatic lesions that pharmacological inhibitors of ERKs as well as hydrogen sulfide not only reduce the basal expression and secretion of IL-8, but also interfere with IL-17- and IL-22-induced IL-8 production. These observations, together with the known anti-inflammatory activity of H₂S, are relevant to understanding some previously unexplained biological effects exerted by sulfur therapy.
Laboratory Investigation 05/2011; 91(8):1188-94. · 3.64 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: PKC isoenzymes play central roles in various cellular signalling pathways, participating in a variety of protein phosphorylation cascades that regulate/modulate cellular structure and gene expression. It has been firmly established that several isoforms of PKC have a role in the regulation of tumor necrosis factor-related apoptosis inducing ligand (TRAIL) activity. Our interest in probing the role of the epsilon isoform of PKC in the colonic cell differentiation stems from the discovery that PKCε and TRAIL are involved in the differentiation of other cell types like hematopoietic stem cells. Although the role of PKCε and TRAIL in the gastrointestinal system is unclear, it has been observed that PKCε has oncogenic activity in colon epithelial cells (CEC), while TRAIL increases the death of intestinal epithelial cells during inflammation. Here we demonstrate a reciprocal expression of PKCε and TRAIL in human colon mucosa: CECs at the bottom of the colonic crypts show high levels of PKCε, being negative for TRAIL expression. On the contrary, luminal CECs are positive for TRAIL, while negative for PKCε. Indeed, TRAIL- and butyrate-induced differentiation of the human colorectal cancer cell line HT29 requires the decrease of PKCε expression, whose absence in turn increases cell sensitivity to TRAIL-induced apoptosis. Moreover, TRAIL preferentially promotes HT29 differentiation into goblet cells. Taken together, this data demonstrate that TRAIL and PKCε must be reciprocally regulated to ensure physiological CEC differentiation starting from the stem cell pool, and that the down-regulation of PKCε is however critical for the differentiation and apoptosis of cancer cells.
Journal of Cellular Physiology 04/2011; 227(2):630-8. · 3.87 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Tumor oxygen status is considered as a prognostic marker that impacts on malignant progression and outcome of tumor therapy. TNF-related apoptosis inducing ligand (TRAIL) plays a key role in cancer immunity, with potential applications in cancer therapy. Protein kinase C (PKC)epsilon, a transforming oncogene, has a role in the protection of cardiomyocytes and neurons from hypoxia-induced damage while, it can also modulate the susceptibility of tumor cells to TRAIL-induced cell death. Here we demonstrate that hypoxia induces a tumor cell phenotype highly sensitive to the cytotoxic effects of TRAIL. Based on the observation that: i) PKCepsilon expression levels are impaired during hypoxia, ii) the overexpression of PKCepsilon, but not of a kinase-inactive PKCepsilon mutant, is able to revert the hypoxia-induced sensitivity to TRAIL, iii) the down-modulation of PKCepsilon levels by RNA interference, on the contrary, induces the highly TRAIL-sensitive phenotype, iv) the inhibition of hypoxia-inducible transcription factor-1alpha (HIF-1alpha) by specific siRNA blocks both the hypoxia-induced down-modulation of PKCepsilon and the induction of the highly TRAIL-sensitive phenotype; we conclude that the HIF-1alpha upregulation during hypoxia is associated to PKCepsilon down-modulation that likely represents the key molecular event promoting the apoptogenic effects of TRAIL in hypoxic tumor cells.
International Journal of Oncology 09/2010; 37(3):719-29. · 2.40 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Despite the relevant therapeutic progresses made in these last 2 decades, the prognosis of acute myeloid leukemia (AML) remains poor. Phorbol esters are used at very low concentrations as differentiating agents in the therapy of myeloid leukemias. Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), in turn, is a death ligand that spares normal cells and is therefore currently under clinical trials for cancer therapy. Emerging evidence, however, suggests that TRAIL is also involved in nonapoptotic functions, like cell differentiation. PKCepsilon is differentially modulated along normal hematopoiesis, and its levels modulate the response of hematopoietic precursors to TRAIL. Here, we investigated the effects of the combination of phorbol esters (phorbol ester 4-beta-phorbol-12,13-dibutyrate [PDBu]) and TRAIL in the survival/differentiation of AML cells. We demonstrate here that PDBu sensitizes primary AML cells to both the apoptogenic and the differentiative effects of TRAIL via PKCepsilon down-modulation, without affecting TRAIL receptor surface expression. We believe that the use of TRAIL in combination with phorbol esters (or possibly more specific PKCepsilon down-modulators) might represent a significative improvement of our therapeutic arsenal against AML.
Blood 12/2008; 113(13):3080-7. · 9.90 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Protein kinase C (PKC)-mediated intracellular signaling participates in several key steps of hematopoietic cell differentiation. The epsilon isoform of PKC has been associated with erythroid differentiation as well as with the early phases of megakaryocytic (MK) lineage commitment. Here, we worked on the hypothesis that PKCepsilon expression levels might be modulated during MK differentiation, with a specific role in the early as well as in the late phases of thrombopoiesis. We demonstrate that--at variance with the erythroid lineage development--PKCepsilon is completely downmodulated in TPO-induced CD34 cells from day 6 onward. The forced expression of PKCepsilon in the late phases of MK differentiation delays the phenotypic differentiation of progenitors likely via Bcl-xL upregulation. Moreover, tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), known as a negative regulator of early erythroid expansion, is not apoptogenic for thrombopoietin-induced CD34 cells, but rather accelerates their maturation. However, PKCepsilon levels negatively interfere also with the effects of TRAIL in MK differentiation. PKCepsilon can therefore be considered a signaling intermediate whose expression levels are finely tuned, with a virtually opposite kinetic, in erythroid versus megakaryocytic lineages, to adequately respond to the signaling requirements of the specific hematopoietic lineage.
Stem Cells 10/2007; 25(9):2322-9. · 7.78 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Protein kinase C (PKC)-mediated intracellular signaling participates in several key steps of hematopoietic cell differentiation. The ε isoform of PKC has been associated with erythroid differentiation as well as with the early phases of megakaryocytic (MK) lineage commitment. Here, we worked on the hypothesis that PKCε expression levels might be modulated during MK differentiation, with a specific role in the early as well as in the late phases of thrombopoiesis. We demonstrate that—at variance with the erythroid lineage development—PKCε is completely downmodulated in TPO-induced CD34 cells from day 6 onward. The forced expression of PKCε in the late phases of MK differentiation delays the phenotypic differentiation of progenitors likely via Bcl-xL upregulation. Moreover, tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), known as a negative regulator of early erythroid expansion, is not apoptogenic for thrombopoietin-induced CD34 cells, but rather accelerates their maturation. However, PKCε levels negatively interfere also with the effects of TRAIL in MK differentiation. PKCε can therefore be considered a signaling intermediate whose expression levels are finely tuned, with a virtually opposite kinetic, in erythroid versus megakaryocytic lineages, to adequately respond to the signaling requirements of the specific hematopoietic lineage.Disclosure of potential conflicts of interest is found at the end of this article.
Stem Cells 08/2007; 25(9):2322 - 2329. · 7.78 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Hydrogen sulfide, together with carbon monoxide and nitric oxide, is now considered a gasotransmitter able to induce specific cellular responses. As hydrogen sulfide is a component of several natural compounds known to be effective in many inflammatory pathologies, particularly of the respiratory tract, we studied its effects in vitro on the survival and bactericidal activity of purified human neutrophils. We found that (1) HS(-) ions promote the survival of granulocytes, but not that of lymphocytes or eosinophils, cultured in serum-free medium; (2) the pro-survival effect of HS(-) is due to inhibition of caspase-3 cleavage and p38 MAP kinase phosphorylation; (3) the bactericidal activity of neutrophils is not impaired by hydrogen sulfide. We conclude that HS(-) promotes the short-term survival of neutrophils potentially accelerating the resolution of inflammatory processes and preventing the occurrence of new ones.
Laboratory Investigation 05/2006; 86(4):391-7. · 3.64 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Human herpesvirus (HHV)-7 is a ubiquitous virus that infects >90% of adults. We show that HHV-7 impairs beta2-microglobulin and human leukocyte antigen (HLA) class I and II expression in lymphoid cells in vitro. Accordingly, infected cells were more sensitive to peripheral blood natural cytotoxic activity than were uninfected cells. Analysis of beta2-microglobulin and HLA expression in biopsy specimens from human submandibular glands confirmed the ability of HHV-7 to modulate the expression of these antigens in vivo. We demonstrate that the down-modulation of HLA by HHV-7 is linked to viral replication and is not merely a consequence of the interaction of virions with the cell surface. Infected cells can therefore efficiently escape host immune pressure, which might explain the persistence of HHV-7-positive cells in several kinds of tumors and chronic infectious diseases.
The Journal of Infectious Diseases 04/2006; 193(7):917-26. · 6.41 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: To investigate TAP1, TAP2, and HLA class I antigen expression in primary ovarian carcinoma lesions and to assess the clinical significance of defects in the expression of these molecules.
Fifty-one formalin-fixed, paraffin-embedded primary ovarian carcinoma lesions were stained with affinity-purified rabbit anti-TAP1 and anti-TAP2 antibodies and with anti-HLA class I heavy chain monoclonal antibody (mAb) HC-10 using the immunoperoxidase reaction. The results of immunohistochemical staining were correlated with the histopathologic characteristics of the lesions and with patients' survival.
Ovarian surface epithelium, thecal cells of follicles, and stromal cells were stained by anti-TAP1, anti-TAP2, and anti-HLA class I antigen xenoantibodies with a homogeneous pattern. In contrast, no staining of lutheinic cells by these antibodies was detected. Forty-one and 32 out of 51 primary ovarian carcinoma lesions were stained by anti-TAP1 and anti-TAP2 xenoantibodies and by anti-HLA class I antigen mAb HC-10, respectively. The staining patterns by anti-TAP1 and anti-TAP2 xenoantibodies were completely concordant, but did not correlate with that by anti-HLA class I heavy chain mAb HC-10. TAP1 and TAP2 expression was associated neither with the histopathologic characteristics of the lesions nor with clinical variables. On the other hand, HLA class I antigen down-regulation was associated with disease stage: the odds ratio of stage III for HLA class I antigen negative patients was 7.6 (95% confidence interval, 1.9-30.5; P= 0.007), whereas for TAP negative patients was 5.1 (95% confidence interval, 0.9-28.4; P = 0.07). Follow up was available for 39 out of the 51 patients. Multivariate analysis showed that both grading and staging were associated with a higher risk of death, whereas TAP and HLA class I antigen phenotypes were not.
The lack of association between TAP and HLA class I antigen expression is compatible with the possibility that multiple mechanisms underlie HLA class I antigen down-regulation in primary ovarian carcinoma lesions. The potential role of immunologic events in the clinical course of ovarian carcinoma suggests that the association between HLA class I antigen down-regulation and disease progression may reflect the escape of tumor cells from immune recognition and destruction.
Clinical Cancer Research 02/2005; 11(1):67-72. · 7.74 Impact Factor
-
Giuliana Gobbi,
Prisco Mirandola, Cristina Micheloni,
Elvira Solenghi,
Ivonne Sponzilli,
Marco Artico,
Giuseppe Soda,
Giuliana Zanelli,
Giuseppe Pelusi,
Tania Fiorini,
Lucio Cocco,
Marco Vitale
[show abstract]
[hide abstract]
ABSTRACT: Malignant transformation of breast epithelia is frequently associated with an altered expression of MHC products and of antigen processing molecular machinery. The consequent impairment of tumor immune recognition is thought to confer to tumor cells a selective advantage with respect to survival and metastatization. In order to understand if metastatic breast cancer lesions might be associated with a defective proteasome subunit expression that, in turn, might limit the peptide availability and prevent stable cell surface HLA class I-tumor antigen expression, we studied by immunostaining the expression of beta2-microglobulin, HLA class I antigens and proteasome subunits LMP-2 and LMP-10 in 35 matched primary and metastatic human breast carcinoma lesions. Overall, we found a downregulation of LMP-2 in 51.4% of the lesions, of LPM-10 in 45.7% of the lesions, of HLA class I heavy chain in 40.0% of the lesions, while beta2-microglobulin was downregulated in 25.7% of the lesions studied. In most primary and metastatic lesions the downmodulation of each antigen examined was coordinated. In the cases where a selective downmodulation of antigens was observed in the primary or in the metastatic lesion (with the exception of beta2-microglobulin), it was rather observed in the primary lesions. However, LMP-10 showed a significant selective downmodulation in the metastases as well. Antigen downmodulation does not appear therefore to represent a strategy for the primary tumor to metastasize successfully.
International Journal of Oncology 01/2005; 25(6):1625-9. · 2.40 Impact Factor
