Biomedical subjects

Thomas Giese

Publications and source records attributed to Thomas Giese.

At least 55 records · Page 3Linked to original sources

PubMed2005

Osteonectin influences growth and invasion of pancreatic cancer cells.

OBJECTIVE: We sought to examine the expression and functional role of osteonectin in primary and metastatic pancreatic ductal adenocarcinoma (PDAC). BACKGROUND: The glycoprotein osteonectin plays a vital role in cell-matrix interactions and is involved in various biologic processes. Overexpression of osteonectin is present in malignant tumors and correlates with disease progression and poor prognosis. METHODS: Expression of osteonectin was analyzed by quantitative polymerase chain reaction and immunohistochemistry in pancreatic tissues and by enzyme-linked immunosorbent assay in the serum of patients and donors. Recombinant osteonectin and specific antisense oligonucleotides were used to examine the effects of osteonectin on induction of target genes, and on proliferation and invasiveness of pancreatic cancer cells. RESULTS: There was a 31-fold increase in osteonectin mRNA levels in PDAC and a 16-fold increase in chronic pancreatitis as compared with the normal pancreas (P < 0.01). By immunohistochemistry, faint immunoreactivity was detected in the normal pancreas. In contrast, strong staining of the cancer cells was observed in addition to extensive osteonectin immunoreactivity in surrounding fibroblasts and in the extracellular matrix. In metastatic tissues, strong immunoreactivity was observed in fibroblasts and in extracellular matrix surrounding metastatic cancer cells, whereas the signal was absent in most tumor cells. In vitro studies showed that osteonectin was able to inhibit cancer cell growth while promoting invasiveness of pancreatic tumor cells. CONCLUSION: Osteonectin is markedly overexpressed in pancreatic cancer and has the potential to increase the invasiveness of pancreatic cancer cells.

Adenocarcinoma↗

PubMed2005

The Notch signaling pathway is related to neurovascular progression of pancreatic cancer.

OBJECTIVE: To analyze the potential role of the Notch signaling pathway in pancreatic cancer angiogenesis and invasion. BACKGROUND: Angiogenesis, pain, and early neuroinvasion are clinical features of pancreatic cancer. Blood vessels and nerves develop together and use common routes through the organism. The Notch pathway (Notch-1/4, Jagged-1/2, Delta-1) appears crucial in this process. The current study analyzed the Notch pathway in pancreatic cancer and characterized its angiogenic and invasive effects. METHODS: Five PaCa cell lines were cultured for the in vitro experiments. Real-time quantitative RT-PCR was done to quantify mRNA expression in 31 human PaCa specimens, and immunohistochemistry was used to localize protein expression within tumor specimens. Activation of the Notch signaling was done by transfection of PaCa cells with a constitutive active Notch-1 mutant (Notch-IC). Overexpression of Jagged and Delta was achieved by transfection of full-length cDNA. Spheroid assays were used to study angiogenesis and ELISAs to measure VEGF, bFGF, and angiogenin expression. Matrigel invasion assays were used to analyze tumor cell invasion. RESULTS: Notch-3 and Notch-4 mRNA were significantly (P < 0.001) overexpressed in PaCa. Immunohistochemistry revealed protein accumulation of Notch-1 as well. All ligands were significantly up-regulated. A positive immunosignal of ligands was seen in nerves, blood vessels, and ductal tumor cells. Transfection of PaCa cells with the constitutive active Notch-IC mutant and with Jagged-1 revealed increased levels for VEGF. Concomitantly, recombinant Jagged-1 increased sprouting of endothelial cells in the spheroid assay. CONCLUSION: The Notch pathway most likely regulates neurovascular development in pancreatic cancer. Activation of this signaling pathway by constitutive Notch-1 mutants and by Jagged-1 causes an angiogenic and invasive tumor phenotype. Specific blockade of Notch signaling may therefore be beneficial for patients with pancreatic cancer.

Disease Progression↗

PubMed2005

Quantification of melanoma micrometastases in sentinel lymph nodes using real-time RT-PCR.

Detection of micrometastases in the regional tumor-draining lymph nodes is critical for staging and prognosis in melanoma patients. We applied a quantitative multiple-marker RT-PCR assay to improve the detection of occult melanoma cells in the sentinel lymph node (SLN). From 139 patients with primary cutaneous melanoma who underwent sentinel lymphadenectomy, a total of 235 SLN were assessed for Melan-A and tyrosinase expression by real-time quantitative RT-PCR. Twenty-three patients (17%) were positive by histopathology and expressed messenger RNA of one or two markers. Of the patients with histopathologically negative SLN 39 (28%) were reclassified by positive RT-PCR. Patients were examined for tumor recurrences during a median follow-up period of 29 mo. Tumor recurrences were demonstrated in eight patients (35%) with histopathologically positive SLN, in four patients (10%) with submicroscopic tumor cells detected exclusively by real-time RT-PCR, and in none of the patients negative by both methods. The differences in recurrence rates were statistically significant (p=0.01). These data indicate that real-time quantitative RT-PCR for the detection of minimal residual melanoma in SLN improves the prediction of disease-free survival.

Antigens, Neoplasm↗

PubMed2005

B1 lymphocytes and myeloid dendritic cells in lymphoid organs are preferential extratumoral sites of parvovirus minute virus of mice prototype strain expression.

Due to their oncolytic properties and apathogenicity, autonomous parvoviruses have attracted significant interest as possible anticancer agents. Recent preclinical studies provided evidence of the therapeutic potential of minute virus of mice prototype strain (MVMp) and its recombinant derivatives. In a murine model of hemangiosarcoma, positive therapeutic outcome correlated with high intratumoral expression of MVMp-encoded genes in tumors and lymphoid organs, especially in tumor-draining lymph nodes. The source and relevance of this extratumoral expression, which came as a surprise because of the known fibrotropism of MVMp, remained unclear. In the present study, we investigated (i) whether the observed expression pattern occurs in different tumor models, (ii) which cell population is targeted by the virus, and (iii) the immunological consequences of this infection. Significant MVMp gene expression was detected in lymphoid tissues from infected tumor-free as well as melanoma-, lymphoma-, and hemangiosarcoma-bearing mice. This expression was especially marked in lymph nodes draining virus-injected tumors. Fluorescent in situ hybridization analysis, multicolor fluorescence-activated cell sorting, and quantitative reverse transcription-PCR revealed that MVMp was expressed in rare subpopulations of CD11b (Mac1)-positive cells displaying CD11c+ (myeloid dendritic cells [MDC]) or CD45B (B220+ [B1 lymphocytes]) markers. Apart from the late deletion of cytotoxic memory cells (CD8+ CD44+ CD62L-), this infection did not lead to significant alteration of the immunological profile of cells populating lymphoid organs. However, subtle changes were detected in the production of specific proinflammatory cytokines in lymph nodes from virus-treated animals. Considering the role of B1 lymphocytes and MDC in cancer and immunological surveillance, the specific ability of these cell types to sustain parvovirus-driven gene expression may be exploited in gene therapy protocols.

Animals↗

PubMed2005

Expression analysis of PMP22/Gas3 in premalignant and malignant pancreatic lesions.

PMP22 is a structural protein of Schwann cells, but it also influences cell proliferation. In the present study, quantitative RT-PCR (QRT-PCR) and immunohistochemistry were used to determine PMP22 mRNA levels and to localize PMP22 in the normal pancreas (n=20), chronic pancreatitis (CP) (n=22), pancreatic ductal adenocarcinoma (PDAC) (n=31), intraductal papillary mucinous neoplasms (IPMN) (n=9), mucinous cystic tumors (MCN) (n=4), and in a panel of PanIN lesions (n=29). PMP22 mRNA levels were significantly higher in CP (3-fold) and PDAC (2.5-fold), compared to normal pancreatic tissues. PMP22 expression was restricted to nerves in the normal pancreas, while in CP and PDAC PMP22 was also expressed in PanIN lesions and in a small percentage of pancreatic cancer cells. PMP22 was weak to absent in the tumor cells of IPMNs and MCNs. PMP22 mRNA was present at different levels in cultured pancreatic cancer cells and up-regulated by transforming growth factor (TGF)-beta1 in 2 of 8 of these cell lines. In conclusion, PMP22 expression is present in both CP and PDAC tissues. Its expression in PanIN lesions and some pancreatic cancer cells in vitro and in vivo suggests a role of PMP22 in the neoplastic transformation process from the normal pancreas to pre-malignant lesions to pancreatic cancer.

Adult↗

PubMed2004

Preferential expression and function of Toll-like receptor 3 in human astrocytes.

In contrast to other tissues, the central nervous system (CNS) is essentially devoid of MHC expression and shielded from antibodies by the blood-brain barrier. Therefore, a rapid local innate immune response by resident brain cells is required to effectively fight infectious agents. This study analyzed the expression and function of Toll-like receptors (TLRs) in cultured human astrocytes. Quantitative PCR for TLRs 1 to 10 showed a basal expression of TLR3 that could be enhanced by IFN-gamma, IL-1beta, and IFN-beta. The other TLRs were barely detectable and not inducible by the same cytokines. IFN-gamma-activated astrocytes responded to TLR3 ligand poly (I:C) engagement with IL-6 production, while ligands of other TLRs, like LPS, lipoteichoic acid, peptidoglycan, flagellin, and CpG, had no effect. Poly (I:C) also triggered astrocyte production of TNF-alpha and the chemokines CCL2/MCP-1, CCL5/RANTES, CCL20/MIP-3alpha, and CXCL10/IP-10. The adapter molecules MyD88 (full length and short isoform), TIRAP/Mal, and TICAM-1/TRIF, which are required for TLR signaling, were all expressed by astrocytes. Thus, resting and activated human astrocytes express preferentially TLR3 and, upon TLR3 engagement, produce IL-6 and chemokines active on T cells, B cells, monocytes, and dendritic cells. These data indicate that astrocytes function as sentinels for viral infections in the CNS.

Adaptor Proteins, Signal Transducing↗

PubMed2004

Pancreatic tumor cells influence the composition of the extracellular matrix.

The malignant behavior of cancers depends on the microenvironmental context. We investigated compositional alterations of the extracellular matrix (ECM) in pancreatic cancer, with special emphasis on the proteoglycans decorin, lumican, and versican. Compared with normal controls (n=18), marked overexpression of these proteoglycans was observed in pancreatic cancer tissues (n=30) by quantitative RT-PCR (p<0.0001). Immunohistochemistry revealed abundance of proteoglycans in the ECM of pancreatic cancer specimens, whereas tumor cells themselves were devoid of either decorin, lumican or versican. RT-PCR confirmed pancreatic stellate cells (PSCs) as the major source of these proteins. Interestingly, TGFbeta1 and conditioned medium derived from pancreatic cancer cell lines synergistically suppressed the expression of known anti-tumor factors decorin and lumican, but stimulated the expression of pro-metastatic factor versican in cultured PSCs. These findings indicate that malignant cells can actively influence the composition of the ECM through TGFbeta1 and other soluble factors, altering their microenvironment in a tumor-favorable way.

Adenocarcinoma↗

PubMed2004

Shaping phenotype, function, and survival of dendritic cells by cytomegalovirus-encoded IL-10.

Human dendritic cells (DCs) are essential for the antiviral immune response and represent a strategically important target for immune evasion of viruses, including human CMV (HCMV). Recently, HCMV has been discovered to encode a unique IL-10 homologue (cmvIL-10). In this study we investigated the capacity of cmvIL-10 to shape phenotype, function, and survival of DCs. For comparison we included human IL-10 and another IL-10 homologue encoded by EBV, which does not directly target DCs. Interestingly, cmvIL-10 strongly activated STAT3 in immature DCs despite its low sequence identity with human IL-10. For most molecules cmvIL-10 blocked LPS-induced surface up-regulation, confirming its role as an inhibitor of maturation. However, a small number of molecules on LPS-treated DCs including IDO, a proposed tolerogenic molecule, showed a different behavior and were up-regulated in response to cmvIL-10. Intriguingly, the expression of C-type lectin DC-specific ICAM-grabbing nonintegrin, a receptor for HCMV infection found exclusively on DCs, was also enhanced by cmvIL-10. This phenotypic change was mirrored by the efficiency of HCMV infection. Moreover, DCs stimulated with LPS and simultaneously treated with cmvIL-10 retained the function of immature DCs. Finally, cmvIL-10 increased apoptosis associated with DC maturation by blocking up-regulation of the antiapoptotic long form cellular FLIP. Taken together, these findings show potential mechanisms by which cmvIL-10 could assist HCMV to infect DCs and to impair DC function and survival.

Apoptosis↗

PubMed2004

Desmoplastic reaction influences pancreatic cancer growth behavior.

Connective tissue growth factor (CTGF), which is regulated by transforming growth factor-ss (TGFss), has recently been implicated in the pathogenesis of fibrotic diseases and tumor stroma. Inasmuch as generation of desmoplastic tissue is characteristic for pancreatic cancer, it is not known whether it gives pancreatic cancer cells a growth advantage or is a reaction of the body to inhibit cancer cell progression. In the present study we analyzed the expression and localization of CTGF and evaluated whether it influences the prognosis of pancreas cancer. Tissue samples were obtained from 25 individuals (6 women, 19 men) undergoing pancreatic resection for pancreatic cancer. Tissue samples from 13 previously healthy organ donors (5 women, 8 men) served as controls. Expression of CTGF was studied by Northern blot analysis. In situ hybridization and immunohistochemistry localized the respective mRNA moieties and proteins in the tissue samples. Northern blot analysis revealed that pancreatic cancer tissue samples exhibited a 46-fold increase in CTGF mRNA expression ( p < 0.001) over that of normal controls. In vitro studies confirmed that pancreatic stellate cells are the major source of CTGF mRNA expression and revealed a large variance in basal and TGFss-induced CTGF expression in cultured pancreatic cancer cells. This could also be confirmed by in situ hybridization, indicating that CTGF mRNA signals were located principally in fibroblasts, with only weak signals in the cancer cells. High CTGF mRNA levels in the tissue samples correlated with better tumor differentiation ( p < 0.03). In addition, patients whose tumors exhibited high CTGF mRNA levels (> onefold increase above normal controls) lived significantly longer than those whose tumors expressed low CTGF mRNA levels (none to onefold) ( p < 0.04 multivariate analysis). Our present data indicate that CTGF, as a downstream mediator of TGFss, is overexpressed in connective tissue cells and to a lesser extent in pancreatic cancer cells. Because patients with high CTGF mRNA expression levels have a better prognosis, our findings indicate that the desmoplastic reaction provides a growth disadvantage for pancreatic cancer cells.

Adenocarcinoma↗

PubMed2004

Overexpressed decorin in pancreatic cancer: potential tumor growth inhibition and attenuation of chemotherapeutic action.

PURPOSE: The aim of this study was to investigate the expression and significance of decorin in pancreatic cancer. EXPERIMENTAL DESIGN: Decorin expression in normal pancreas and excised tumors was examined by real-time quantitative PCR, Western blot analysis, and immunohistochemistry. Reverse transcription-PCR was used to analyze cultures of pancreatic cancer and stellate cells. Growth-inhibitory effects of decorin in vitro were assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide test, Western blot, and fluorescence-activated cell-sorting analysis. RESULTS: Pancreatic cancer was characterized by striking overexpression of decorin mRNA in tumor tissues (9-fold by real-time quantitative PCR; 44 patients versus 18 healthy donors; P < 0.01). Strong decorin immunostaining was observed in the extracellular matrix of pancreatic cancer tissue, whereas tumor cells were devoid of decorin. Double staining for anti-smooth muscle actin and decorin and reverse transcription-PCR analysis of primary cultures revealed pancreatic stellate cells as the putative source of decorin. Human recombinant decorin was able to suppress growth of pancreatic cancer cells in vitro through p21 mediated G(1)-S block of the cell cycle. However, in contrast to the previously described chemotherapy-potentiating capacity of decorin, this proteoglycan attenuated the cytostatic action of carboplatin and gemcitabine toward pancreatic cancer cells. CONCLUSIONS: Decorin might exert an antiproliferative effect toward pancreatic cancer cells, thus playing a role in a host stromal reaction aimed at sequestering and inhibiting growing malignant cells. However, in clinical settings, the importance of collagen-associated decorin as a moderate antitumor modality would be undermined by its ability to attenuate the efficiency of chemotherapeutics. Considering the general failure of adjuvant therapies in pancreatic cancer, the role of decorin in this process warrants further investigation.

Adult↗

PubMed2004

Indian hedgehog signaling pathway: expression and regulation in pancreatic cancer.

Pancreatic cancer is an aggressive malignancy that exhibits a number of genetic and epigenetic alterations. Indian hedgehog (Ihh) and its 2 signaling receptors, patched (Ptc) and smoothened (Smo), are involved in pancreatic development and regulation of beta-cell function as well as in certain human tumors. In the current study, we analyzed the expression, distribution and function of Ihh and its receptors in pancreatic cancer. Quantitative RT-PCR and immunohistochemistry were utilized to analyze the expression, localization and transcriptional regulation of Ihh, Ptc and Smo. The effects of inhibition and stimulation of the hedgehog signaling pathway on pancreatic cancer cell growth were examined by the MTT cell growth assay. By quantitative RT-PCR, Ihh, Ptc and Smo mRNA levels were increased 35-, 1.2- and 1.6-fold, respectively, in pancreatic cancer tissues in comparison to normal pancreatic tissues. By immunohistochemistry, Ihh, Ptc and Smo were expressed in the islet cells of normal and cancerous tissues and in pancreatic cancer cells. The growth of pancreatic cancer cells was dose-dependently inhibited by the hedgehog antagonist cyclopamine through G0/G1 arrest. In contrast, Ihh agonists exhibited no significant effect on pancreatic cancer cell growth. TGF-beta1 repressed Ihh transcription in a TGF-beta1-responsive pancreatic cancer cell line, but had no effect on the other tested cell lines. In conclusion, Ihh and its receptors Ptc and Smo are expressed in pancreatic cancer, and blockage of hedgehog signaling results in inhibition of pancreatic cancer cell growth, suggesting that aberrant activation of the Ihh signaling pathway contributes to tumor development in this malignancy.

Adult↗

PubMed2004

Characterization of FAMPAC, a newly identified human pancreatic carcinoma cell line with a hereditary background.

BACKGROUND: A novel pancreatic carcinoma cell line, FAMPAC, was identified from investigation of poorly differentiated pancreatic adenocarcinoma cells found in a patient with a familial predisposition to pancreatic carcinoma. A gene responsible for familial pancreatic carcinoma has not been identified to date. METHODS: The FAMPAC cell line was characterized by its morphology, growth rate, tumorigenicity, and chromosomal analysis. Three known tumor suppressor genes, p16/CDKN2, BRCA2, and p53, all of which are important in the development of pancreatic carcinoma and frequently are involved in a variety of cancer syndromes, were analyzed. RESULTS: FAMPAC cells grew as an adhering monolayer in culture medium supplemented with 10% fetal bovine serum and formed tumors rapidly in nude mice. The doubling time ranged from 24 to 48 hours. Karyotype analysis demonstrated the complexity of chromosomal deletions and rearrangements. The cells were negative for ductal differentiation markers such as cytokeratin 7 and MUC1, indicating poor differentiation. Analysis of FAMPAC cells revealed overexpression of the mutated p53 gene (exon 5, codon 175: CGC --> CAC), the presence of a homozygous deletion in the p16 gene, and the presence of wild-type BRCA2 in the tested hot spots. CONCLUSIONS: To the authors' knowledge, FAMPAC is the first established human pancreatic carcinoma cell line associated with a familial background. FAMPAC is a tumorigenic cell line with a complex molecular pattern of mutations. These findings may be useful in understanding the mechanisms responsible for the development of sporadic or hereditary forms of pancreatic carcinoma.

Adult↗

PubMed2004

Enhanced expression of 14-3-3sigma in pancreatic cancer and its role in cell cycle regulation and apoptosis.

14-3-3sigma belongs to the 14-3-3 family of proteins, which are involved in the modulation of diverse signal transduction pathways. Loss of 14-3-3sigma expression has been observed in a number of human cancers, suggesting that it may have a role as a tumor suppressor gene. The aim of the study was to investigate the expression and the functional role of 14-3-3sigma in pancreatic ductal adenocarcinoma (PDAC). Expression of 14-3-3sigma was analyzed using laser capture microdissection (LCM), quantitative real-time-PCR (QRT-PCR), DNA arrays, immunohistochemistry and western blot analysis. The role of 14-3-3sigma in apoptosis and cell cycle regulation was evaluated by western blotting, immunoprecipitation and FACS analysis. By QRT-PCR, 14-3-3sigma mRNA levels were 54-fold increased in pancreatic adenocarcinoma in comparison with normal pancreatic samples and localized in pancreatic cancer cells as determined by LCM. In pancreatic cancer cells, the degree of 14-3-3sigma expression was not decisive for the maintenance of G(2)/M cell cycle checkpoint or induction of apoptosis. Responses to radiation or apoptosis-inducing agents were neither accompanied by a significant 14-3-3sigma accumulation nor by a change in association of 14-3-3sigma with cdc2, bad and bax. In conclusion, the marked over-expression of 14-3-3sigma in PADC together with multiple known genetic and epigenetic alterations of potential 14-3-3sigma interacting partners suggests an important role of aberrant 14-3-3sigma downstream signaling in pancreatic cancer.

14-3-3 Proteins↗

PubMed2004

Monitoring of NFAT-regulated gene expression in the peripheral blood of allograft recipients: a novel perspective toward individually optimized drug doses of cyclosporine A.

BACKGROUND: With the introduction of cyclosporine A (CsA), long-term allograft function has significantly improved. Problems related to limited therapeutic margins and CsA toxicity remain unsolved. Until now there have been no reliable, practical markers to measure the biologic activity of CsA in vivo. METHODS: Expression of NFAT (nuclear factor of activated T cells)-regulated genes (interleukin 2, interferon-gamma, and granulocyte-macrophage colony-stimulating factor) in phorbol myristate acetate/ionomycin-stimulated peripheral blood from healthy volunteers (n=34) and from stable renal (n=25), cardiac (n=26), and liver (n=14) transplant recipients receiving CsA therapy was measured by quantitative real-time reverse transcriptase-polymerase chain reaction before and 2 hr after drug intake. Gene expression and CsA plasma levels were correlated. RESULTS: Two hours after oral CsA ingestion, the mean suppression of induced interleukin 2, interferon-gamma, and granulocyte-macrophage colony-stimulating factor gene expression was 85%. The individual decline of NFAT-regulated gene expression and the total drug exposure at this time point were closely related. Six hours after oral CsA uptake, gene expression levels reached predose values and subsequently increased further in some patients (rebound effect). CONCLUSION: Quantitative measurement of the inhibition of NFAT-regulated gene expression 2 hr after CsA intake represents a novel approach to assess the biologic effectiveness of CsA therapy and has the potential to enable individualized immunosuppressive regimens.

Adult↗

PubMed2004

Cofilin peptide homologs interfere with immunological synapse formation and T cell activation.

The formation of supramolecular activation clusters within the immunological synapse, crucial for sustained signaling and T lymphocyte activation, requires costimulation-dependent reorganization of the actin cytoskeleton. Here we have identified the actin-remodeling protein cofilin as a key player in this process. Cell-permeable peptides that block costimulation-induced cofilin/F-actin interactions in untransformed human T lymphocytes impair receptor capping and immunological synapse formation at the interface between T cells and antigen-presenting cells. As a consequence, T cell activation, as measured by cytokine production and proliferation, is inhibited.

Actin Depolymerizing Factors↗

PubMed2004

IL-12p70-dependent Th1 induction by human B cells requires combined activation with CD40 ligand and CpG DNA.

The detection of microbial molecules via Toll-like receptors (TLR) in B cells is not well characterized. In this study, we found that both naive and memory B cells lack TLR4 (receptor for LPS) but express TLR9 (receptor for CpG motifs) and produce IL-6, TNF-alpha, and IL-10 upon stimulation with CpG oligonucleotides (ODN), synthetic mimics of microbial DNA. Consistent with the lack of TLR4, purified B cells failed to respond to LPS. Similar to CpG ODN, CD40 ligand (CD40L) alone induced IL-6, TNF-alpha, and IL-10. Production of these cytokines as well as IgM synthesis was synergistically increased when both CpG ODN and CD40L were combined. Unlike IL-6, TNF-alpha, and IL-10, the Th1 cytokine IL-12p70 was detected only when both CpG ODN and CD40L were present, and its induction was independent of B cell receptor cross-linking. CpG ODN did not increase the capacity of CD40L-activated B cells to induce proliferation of naive T cells. However, B cells activated with CpG ODN and CD40L strongly enhanced IFN-gamma production in developing CD4 T cells via IL-12. Together, these results demonstrate that IL-12p70 production in human B cells is under the dual control of microbial stimulation and T cell help. Our findings provide a molecular basis for the potent adjuvant activity of CpG ODN to support humoral immune responses observed in vivo, and for the limited value of LPS.

Adjuvants, Immunologic↗

PubMed2004

Expression and functional significance of CDC25B in human pancreatic ductal adenocarcinoma.

Pancreatic ductal adenocarcinoma (PDAC) is one of the leading causes of cancer-related deaths. Deregulation of cell-cycle control is thought to be a crucial event in malignant transformation, and CDC25 phosphatases are a family of cyclin-dependent kinase activators, which act at different points of the cell cycle, including G1-S and G2-M transition. Here, we investigated the expression and functional significance of CDC25s in PDAC. CDC25B mRNA expression levels in human pancreatic tissue samples were analysed by cDNA array, quantitative PCR and Northern blotting. Immunohistochemistry was carried out to localize and quantify CDC25B expression. Two specific CDC25B inhibitors were utilized to determine the functional relevance of CDC25B. By quantitative RT-PCR, CDC25B mRNA was overexpressed in pancreatic cancer (7.5-fold) in comparison to the normal pancreas. Strong nuclear CDC25B immunoreactivity was present in both pancreatic and metastatic cancer samples, and there was a marked increase of the percentage of positive cells in primary cancer (48.6+/-16.3%) and metastatic tissues (71.7+/-3.1%) compared to normal samples (8.3+/-1.8%). Two CDC25B inhibitors reduced the growth of pancreatic cancer cell lines, resulting in the accumulation of phosphorylated CDC2 and G2/M arrest. These findings demonstrate an important role of CDC25B in cell-cycle progression, raising the possibility that inhibition of CDC25B may have therapeutic potential in pancreatic cancer.

Adenocarcinoma↗

PubMed2004

Frontline: Induction of apoptosis and modulation of c-FLIPL and p53 in immature dendritic cells infected with herpes simplex virus.

Herpes simplex virus (HSV) can perturb the function of dendritic cells (DC). The underlying mechanisms are not defined. In the present study we demonstrate that HSV induces a substantial number of immature DC to undergo apoptosis by a mechanism involving caspase-8. We found strongly enhanced expression of TNF-alpha and TRAIL but not CD95 ligand after HSV infection. Blocking experiments suggested that these classical death ligands contribute to HSV-induced cell death of immature DC. Because uninfected DC are resistant to the apoptosis-inducing effect of death ligands we searched for a viral "competence-to-die" signal. Further analysis revealed that HSV-infected immature DC down-regulate long cellular FLICE-inhibitory protein (c-FLIP(L)) and up-regulate p53 whereas other apoptosis-regulating proteins (e.g. Bcl-2, RIP, FADD) were not affected. Down-regulation of c-FLIP(L) was not due to diminished gene transcription or reduced mRNA stability because the level of c-FLIP(L) mRNA was rather increased. Moreover, down-regulation of c-FLIP(L) could not be blocked by the anti-herpetic drug acyclovir. Finally, the underlying mechanism was also operative in human umbilical vein endothelial cells, which show a similar susceptibility to HSV infection and strength of c-FLIP(L) expression. These results suggest that HSV targets c-FLIP(L) protein in immature DC and other infectable cells to disrupt their function.

Animals↗