1,720,974 research outputs found
The prostate specific membrane antigen regulates the expression of IL-6 and CCL-5 in prostate tumour cells by activating the MAPK pathways
No full textIL-6 and CCL5 are implicated in the development and progression of several forms of tumours incliding PCa. The PSMA expression is augmented in high-grade and metastatic tumours. Some clinical observations suggest that the increased secretion of IL-6 and CCL5 and the higher PSMA expression may be correlated
Filamin A-mediated interaction of Prostate Specific Membrane Antigen (PSMA) with beta1 integrin regulates survival of advanced prostate cancer cells
No full textProstate cancer (Pc) is the second cause of cancer-related death in males of Western countries, due to the poor prognosis of the advanced, androgen-independent, metastatic disease. Advanced Pc cells over-express PSMA, in a drug-resistant, apoptosis-insensitive cell microenvironment where PI3K/AKT/mTOR and RAF/MEK/ERK pathways are constitutively activated, STAT3/NF-kB transactivators increase their function, IL-6 expression is maximized and betat1/beta3 integrins are aberrantly or overexpressed. Whether and how PSMA acts in the generation/maintenance of the advanced Pc phenotype was the topic of our study. PSMA is a trans-membrane folate-hydrolase/carboxypeptidase bearing a binding site for Filamin A (FLNa) in its cytodomain. Previous and herein detailed results by our group demonstrate that PSMA cross-linking signals to PI3K/AKT/mTOR and RAF/MEK/ERK1/2 activation in LNCaP cells (a cell model of advance Pc) and rescues LNCaP from apoptotic stimuli. Both pathways regulate survival and PSMA-mediated rescue. The relevance of FLNa-mediated PSMA/beta1 interaction in these phenomena was shown by the finding that:i) PSMA and beta1 co-localized at the surface of LNCaP cells ii) PSMA cross-linking induced the exposure of HUTS-21 activation epitopes on beta1 and the assembly of a complex including PSMA itself, FLNa, beta1 integrin, pp130CAS and pSrc iii) PSMA- mediated beta1 activation, AKT or ERK1/2 phosphorylation were all hampered by FLNa silencing or Src inhibition with PP1.Collectively, these results first highlights a key role for PSMA/beta1 integrin cooperation in regulating the activation state of advanced Pc cells. Moreover they show that the bridging activity of FLNa can extend the cross-talk of beta1 cytodomain to molecules other than growth factors or cytokine receptors
Prostate Specific Membrane Antigen (PSMA) associates with Filamin A, beta1 integrin, pp130CAS and pSrc thus regulating the activation of beta1 integrin and the survival of prostate cancer cells.
No full textProstate cancer (PCa) is the second cause of cancer-related death in males of developed countries. Up-regulated PSMA expression in aggressive prostate tumors implies a selective advantage for expressing cells and therefore a role for PSMA in cancer cell growth and progression. Previous and herein shown results demonstrate that the PSMA clustering with specific mAb at the cell surface of human prostate carcinoma LNCaP cell line activates beta1 integrin (HUTS-21 epitope), AKT/mTOR/BAD pathway and p38 and ERK1/2 MAPKs, thus promoting cell growth and cell rescue from apoptosis induced by serum deprivation. This occurs thanks to the assembly of a transduction complex including Filamin A (FLNa), beta1 integrin (beta1), phospho-p130CAS and phospho-Src, as demonstrated by cross-immuneprecipitation experiments performed by using either anti PSMA or anti beta1 mAbs. The common location of these molecules in the same Detergent Resistant Membranes (DRMs) is likely to favor their association.
Immunoblottings, FACS analysis and 3D cultures demonstrated that PSMA-induced kinase activation and rescue were hampered or abrogated if FLNa or beta1 or p130CAS were silenced, or if Src was inhibited with SU6656 or PP1 drugs.
It has been previously demonstrated that beta1 associates with Epidermal Growth Factor Receptor (EGFR) thereby regulating its activation state. Based on this, we questioned whether EGFR may be recruited in the signaling complex induced by PSMA activation. Our preliminary results have put into evidence EGFR in the same DRMs as PSMA and beta1. Moreover, immunoblotting of IPs prepared from cell lysate of LNCaP cells after PSMA activation, showed that PSMA and FLNa could be pulled down from EGFR IPs.
In all, our results demonstrate for the first time that PSMA expression gives a remarkable advantage to PCa cells by recruiting a signaling complex, including FLNa, beta1, p130CAS, Src and EGFR, and thereby supporting the activation of antiapototic and pro-proliferative signaling pathways
The Proinflammatory Cytokine, IL-6, and its Interference with bFGF Signaling and PSMA in Prostate Cancer Cells.
No full textThe aim of the present work was to study the expression of the proinflammatory cytokine, interleukin-6 (IL-6), mediated by bFGF signaling and its possible crosstalk with prostate-specific membrane antigen (PSMA) in LNCaP and PC3-PSMA prostate cancer cell lines. PC3 cells stably transfected with PSMA gene were used for restoring PSMA expression. LNCaP and PC3-PSMA cells were exposed to 10 ng/mL of basic fibroblast growth factor (bFGF). IL-6 production was measured by ELISA assay, and levels of PSMA expression were assessed by flow cytometry. AKT, ERK1/2, and p38 phosphorylation were detected by Western blot. bFGF enhances IL-6 production in LNCaP and PC3-PSMA prostate cancer cells. The effect of bFGF on stimulating IL-6 secretion was greater in LNCaP than in PC3-PSMA cells. In the presence of bFGF, PSMA expression was activated after 4 days of treatment in LNCaP and PC3-PSMA cells. This activation was not maintained after long term of treatment in both metastatic cell lines. Solely MAPKs pathways (ERK1/2 and p38) were activated after bFGF stimulation in both metastatic cell lines, whereas AKT did not show any activation. The interference of the proinflammatory cytokine, IL-6, with bFGF signaling and PSMA, should be of high clinical relevance in the treatment of metastatic prostate cancer. In developing novel therapeutic modalities targeting IL-6, significant attention should be given to PSMA and its inactivation to fight against prostate cancer
Lymphoid adhesion promotes human thymic epithelial cell survival via NF-(kappa)B activation.
No full textInside the thymus, thymic epithelial cells and thymocytes show an interdependent relationship for their functional differentiation and development. As regards possible interdependency for their mutual survival, it is clear that lympho-epithelial adhesion can control the survival of developing thymocytes whereas the effects of lymphoid adhesion on epithelial cell survival have never been described. To address this issue, we performed co-cultures between normal human thymic epithelial cells (TEC) and a mature lymphoid T cell line (H9) or unfractionated thymocgtes. TEC were induced to apoptosis by growth factor deprivation and the level of cell death was measured by flow cytometry. TEC stimulated by cell adhesion showed a significant reduced apoptosis when compared to the control and this phenomenon was associated with increased binding activity of NF-κB, as measured by gel shift analysis. The activation of NF-κB was necessary to promote survival, since its inhibition by acetyl salicylic acid prevented the promoting effect. The mAb-mediated crosslinking of α3β1 was considered as a potential inducer of TEC survival, since we have previously demonstrated that the engagement of this integrin was able to induce NF-κB activation in TEC. The crosslinking of α3β1, which clustered at the lympho-epithelial contact sites, partially reproduced the promoting activity of cell adhesion. These results highlight that lympho-epithelial adhesion can control the survival of thymic epithelial cells through an intracellular pathway which requires the activation of NF-κB and is triggered by integrins of the β1 family
The Filamin A-mediated cooperation of Prostate Specific Membrane Antigen (PSMA) with beta1 integrin promotes the survival of aggressive prostate cancer cells.
No full textUp-regulated PSMA expression in aggressive prostate tumors implies a selective advantage for expressing cells and therefore a role for PSMA in cancer cell growth and progression. Previous and herein shown results demonstrate that PSMA clustering at LNCaP surface activates beta1 integrin, AKT/mTOR/BAD pathway and p38 and ERK1/2 MAPKs, thus promoting cell growth and apoptosis resistance. This occurs thanks to the assembly of complexes including Filamin A, beta1 integrin, phospho p130CAS and phospho Src1. Immunoblottings, FACS analysis and 3D cultures demonstrated that PSMA-induced kinase activation and rescue were hampered or abrogated if Filamin A or beta1 integrin were silenced, or if Src1 was inhibited with SU6656 or PP1 drugs. In addition, beta1 integrin activation was halved in Src-inhibited cells or in Filamin A-silenced LNCaP. These results highlight the existence of a PSMA/beta1 integrin cooperation in the LNCaP growth and survival and the Filamin A ability to extend beta1 integrin partnership to molecules other than growth factor or cytokine receptors
Cooperation of Prostate Specific Membrane Antigen with beta 1 integrin promotes the survival of aggressive prostate cancer cells
No full textProstate tumor specimens express high level of Prostate Specific Membrane Antigen (PMSA) associated in 50%-60% of cases with activation of anti apoptotic signaling pathways, transactivators and cytokines genes. Integrins are aberrantly expressed as their signaling adaptor p130CAS. We have previously demonstrated that clustering PSMA with specific mAbs signals to RAS-RAC-MAPK pathway activation, NF-kB translocation, IL-6 gene expression and proliferation in LNCaP cells. Our recent data show that PSMA activates both AKT/mTOR/BAD and MAPK pathways thereby rescuing LNCaP cells from apoptosis. PSMA activity relies on a Filamin A-mediated cooperation with beta1 integrin. PSMA clustering triggers the exposure of HUTS-21 activation epitope on beta1 integrin and the assembling of a complex including PSMA, Filamin A, beta1 integrin, p130CAS and Src1. All these molecules co-localize in the same lipid rafts. PSMA-mediated exposure of HUTS-21 epitope was almost abrogated by Filamin A silencing or Src1 inhibition by PP1. ERK1/2 and AKT phosphorylations were hampered by Filamin A or beta1 silencing or Src1 inhibition. These results first highlights that PSMA/beta1 integrin cooperation regulates apoptosis resistence of LNCaP cells. Moreover they show that the bridging activity of Filamin A can extend the partnership of beta1 integrin to molecules other than growth factors or cytokine receptors
Discriminatory Role of Detergent-Resistant Membranes in the Dimerization and Endocytosis of Prostate-Specific Membrane Antigen.
No full textProstate-specific membrane antigen (PSMA) is a type-II membrane glycoprotein that was initially identified in LNCaP cells. It is expressed at elevated levels in prostate cancer. In view of the correlation between the expression levels of PSMA and disease grade and stage, PSMA is considered to be one of the most promising biomarkers in the diagnosis and treatment of prostate cancer. In LNCaP cells PSMA undergoes internalization via clathrin-coated pits followed by accumulation in the endosomes. PSMA associates with different types of detergent-resistant membranes (DRMs) along the secretory pathway. Its mature form is mainly insoluble in Lubrol WX, but does not associate with Triton X-100-DRMs. To understand the mechanism of PSMA internalization we investigated its association during internalization with DRMs. For this purpose, internalization was induced by antibody cross-linking. We demonstrate at the biochemical and cell biological levels that: [i] exclusively homodimers of PSMA are associated with Lubrol WX-DRMs, [ii] antibody-induced cross-linking of PSMA molecules results in a time-dependent partitioning into another DRMs type, namely Triton X-100-DRMs, and [iii] concomitant with its association with Triton-X-100-DRMs internalization of PSMA occurs along tubulin filaments. In a previous work (Colombatti et al. (2009) PLoS One 4: e4608) we demonstrated that the small GTPases RAS and RAC1 and the MAPKs p38 and ERK1/2 are activated during antibody cross-linking. As downstream effects of this activation we observed a strong induction of NF-kB associated with an increased expression of IL-6 and CCL5 genes and that IL-6 and CCL5 enhanced the proliferative potential of LNCaP cells synergistically. These observations together with findings reported here hypothesize a fundamental role of DRMs during activation of PSMA as platforms for trafficking, endocytosis and signalling. Understanding these mechanisms constitutes an essential prerequisite for utilization of PSMA as a therapeutically suitable target in prostate cancer
Thymocyte contact or monoclonal antibody-mediated clustering of 3beta1 or 6beta4 integrins activate interleukin-6 (IL-6) transcription factors (NF-kappaB and NF-IL6) and IL-6 production in human thymic epithelial cells.
No full textT-cell precursors develop within the thymus in contact with multiple supportive elements, among which thymic epithelial cells (TEC) are known to exert a dominant role in their homing, survival, and functional differentiation. All these functions are supported by cell-cell contacts and cytokine release. Signaling events triggered in lymphoid cells by adhesion to TEC are well characterized, but little is known about the opposite phenomenon. To address this issue, we derived cultures of TEC from human normal thymus. TEC monolayers were cocultured with thymocytes and immunostained with monoclonal antibodies (MoAbs) to integrin (α2, α3, α4, and α6) and β (β1 and β4) chains. Optical and confocal analysis showed that integrins were polarized on TEC at discrete surface locations: α6β4 lined the basal surface of TEC monolayers, whereas α3β1 was found mostly at TEC-TEC contacts; it is noteworthy that both α3β1 and α6β4 became highly enriched also at the boundaries with adherent thymocytes. Functional studies performed with MoAbs anti-β1 and -β4 integrins showed that β1, and, to a much lower extent, β4 heterodimers are involved in the TEC-thymocyte adhesion. Thymocyte contact or MoAb-mediated ligation of α3, α6, β1, and β4 integrins was investigated as a potential inducer of intracellular signaling in TEC. Thymocyte adhesion or cross-linking of MoAbs bound to integrins clustered at the TEC/thymocyte contact sites led to activation of interleukin-6 (IL-6) gene transcription factors, namely NF-IL6 serine phosphorylation and NF-κB nuclear targeting, as well as to increased IL-6 secretion. We propose that integrin clustering occurring during TEC-thymocyte contacts modulates in TEC the gene expression of a cytokine involved in thymocyte growth and functional differentiation
HTLV type IIIB infection of human thymic epithelial cells: viral expression correlates with the induction of NF-kappa B-binding activity in cells activated by cell adhesion.
No full textProductive infection by the LAV strain has been demonstrated in T cell precursors at different stages of intrathymic development, while viral replication in thymic epithelial cells is still controversial. In this article we show that epithelial cell cultures derived from the medullary component of normal thymus are infectable by HTLV-IIIB virus through cell-free and lymphoid-mediated transmission. Free virus inoculum results in the integration of proviral copies undergoing poor replication, whereas lymphoid-mediated transmission leads to substantial viral expression and the production of viral progeny able to secondary infect lymphoid cells. Interleukin 6 production and phenotype changes (increased expression of MHC class I and ICAM-1) were induced in TE cells by contact with free virus or by adhesion to infected lymphoid cells. By contrast, NF-kappa B-binding activity on the HIV-1 LTR kappa B enhancer element was upregulated only by contact with infected lymphoid cells, but not with virus. The viral replication observed in TE cells after lymphoid-mediated transmission correlates with the upregulation of NF-kappa B-binding activity. Interleukin 6 increased production and phenotype changes and increased NF-kappa B-binding activity were also induced by adhesion to uninfected lymphoid cells, demonstrating that lymphoepithelial cell contacts can activate TE cells. These results demonstrate that thymic epithelial cells are permissive to HIV infection and that viral replication in this cell lineage can be modulated by intracellular signals delivered by adhesive contacts
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