GATA4 induces liver fibrosis regression by deactivating hepatic stellate cells

In response to liver injury, hepatic stellate cells activate and acquire proliferative and contractile features. The regression of liver fibrosis appears to involve the clearance of activated hepatic stellate cells, either by apoptosis or by reversion toward a quiescent-like state, a process called deactivation. Thus, deactivation of active hepatic stellate cells has emerged as a novel and promising therapeutic approach for liver fibrosis. However, our knowledge of the master regulators involved in the deactivation and/or activation of fibrotic hepatic stellate cells is still limited. The transcription factor GATA4 has been previously shown to play an important role in embryonic hepatic stellate cell quiescence. In this work, we show that lack of GATA4 in adult mice caused hepatic stellate cell activation and, consequently, liver fibrosis. During regression of liver fibrosis, Gata4 was reexpressed in deactivated hepatic stellate cells. Overexpression of Gata4 in hepatic stellate cells promoted liver fibrosis regression in CCl4-treated mice. GATA4 induced changes in the expression of fibrogenic and antifibrogenic genes, promoting hepatic stellate cell deactivation. Finally, we show that GATA4 directly repressed EPAS1 transcription in hepatic stellate cells and that stabilization of the HIF2α protein in hepatic stellate cells leads to liver fibrosis.

Viral gene delivery vectors: the next generation medicines for immune-related diseases

Viruses have evolved to efficiently express their genes in host cells, which makes them ideally suited as gene delivery vectors for gene and immunotherapies. Replication competent (RC) viral vectors encoding foreign or self-proteins induce strong T-cell responses that can be used for the development of effective cancer treatments. Replication-defective (RD) viral vectors encoding self-proteins are non-immunogenic when introduced in a host naïve for the cognate virus. RD viral vectors can be used to develop gene replacement therapies for genetic disorders and tolerization therapies for autoimmune diseases and allergies. Degenerative/inflammatory diseases are associated with chronic inflammation and immune responses that damage the tissues involved. These diseases therefore strongly resemble autoimmune diseases. This review deals with the use of RC and RD viral vectors for unraveling the pathogenesis of immune-related diseases and their application to the development of the next generation prophylactics and therapeutics for todays' major diseases.

How Simian Virus 40 Hijacks the Intracellular Protein Trafficking Pathway to Its Own Benefit … and Ours

Viruses efficiently transfer and express their genes in host cells and evolve to evade the host's defense responses. These properties render them highly attractive for use as gene delivery vectors in vaccines, gene, and immunotherapies. Among the viruses used as gene delivery vectors, the macaque polyomavirus Simian Virus 40 (SV40) is unique in its capacity to evade intracellular antiviral defense responses upon cell entry. We here describe the unique way by which SV40 particles deliver their genomes in the nucleus of permissive cells and how they prevent presentation of viral antigens to the host's immune system. The non-immunogenicity in its natural host is not only of benefit to the virus but also to us in developing effective SV40 vector-based treatments for today's major human diseases.

Flow Cytometric and Immunohistochemical Correlations in High Incidence Human Solid Tumors

475 patients with carcinoma at different sites (141 colon-rectum; 102 breast; 50 stomach; 48 kidney; 46 head and neck; 41 bladder; 47 other sites) submitted to surgery have been analyzed after histopathological staging and grading, by flow cytometry (monoparametric DNA content analysis) and immunohistochemistry (p53, c-erbB-2, and PCNA expression). In breast cancer patients the presence of receptors for estrogen (ER) and progesterone (PGR) has also been determined. Flow cytometry-derived parameters were DNA ploidy, fraction of cells in S-phase (SPF), and DNA content heterogeneity (multiclonal stem cell lines with different DNA index and/or more than one subpopulations with different ploidy levels in different samples from the same tumor). Correlations of the results obtained by the different techniques have been attempted by the non-parametric Spearman's rank correlation approach. Significant associations (P «0.05) were found between the histopathological, immunohistochemical and flow cytometric parameters considered in some anatomical regions, such as stomach (p53 vs DNA content aneuploidy and vs heterogeneity), colon-rectum (TNM vs p53 and vs heterogeneity), bladder (grading vs DNA content aneuploidy and vs heterogeneity). Tumor heterogeneity proved to be dependent on the number of tumor samples taken. The results of this preliminary assessment will subsequently be compared with the data obtained from a currently ongoing follow-up survey.

Absence of WASp Enhances Hematopoietic and Megakaryocytic Differentiation in a Human Embryonic Stem Cell Model

The Wiskott-Aldrich syndrome (WAS) is an X-linked primary immunodeficiency caused by mutations in the WAS gene and characterized by severe thrombocytopenia. Although the role of WASp in terminally differentiated lymphocytes and myeloid cells is well characterized, its role in early hematopoietic differentiation and in platelets (Plts) biology is poorly understood. In the present manuscript, we have used zinc finger nucleases targeted to the WAS locus for the development of two isogenic WAS knockout (WASKO) human embryonic stem cell lines (hESCs). Upon hematopoietic differentiation, hESCs-WASKO generated increased ratios of CD34⁺CD45⁺ progenitors with altered responses to stem cell factor compared to hESCs-WT. When differentiated toward the megakaryocytic linage, hESCs-WASKO produced increased numbers of CD34⁺CD41⁺ progenitors, megakaryocytes (MKs), and Plts. hESCs-WASKO-derived MKs and Plts showed altered phenotype as well as defective responses to agonist, mimicking WAS patients MKs and Plts defects. Interestingly, the defects were more evident in WASp-deficient MKs than in WASp-deficient Plts. Importantly, ectopic WAS expression using lentiviral vectors restored normal Plts development and MKs responses. These data validate the AND-1_WASKO cell lines as a human cellular model for basic research and for preclinical studies for WAS.

Mesenchymal stromal cells express GARP/LRRC32 on their surface: effects on their biology and immunomodulatory capacity

Mesenchymal stromal cells (MSCs) represent a promising tool for therapy in regenerative medicine, transplantation, and autoimmune disease due to their trophic and immunomodulatory activities. However, we are still far from understanding the mechanisms of action of MSCs in these processes. Transforming growth factor (TGF)-β1 is a pleiotropic cytokine involved in MSC migration, differentiation, and immunomodulation. Recently, glycoprotein A repetitions predominant (GARP) was shown to bind latency-associated peptide (LAP)/TGF-β1 to the cell surface of activated Foxp3⁺ regulatory T cells (Tregs) and megakaryocytes/platelets. In this manuscript, we show that human and mouse MSCs express GARP which presents LAP/TGF-β1 on their cell surface. Silencing GARP expression in MSCs increased their secretion and activation of TGF-β1 and reduced their proliferative capacity in a TGF-β1-independent manner. Importantly, we showed that GARP expression on MSCs contributed to their ability to inhibit T-cell responses in vitro. In summary, we have found that GARP is an essential molecule for MSC biology, regulating their immunomodulatory and proliferative activities. We envision GARP as a new target for improving the therapeutic efficacy of MSCs and also as a novel MSC marker. Stem Cells2015;33:183–195

Mesenchymal Stem Cells Expressing Vasoactive Intestinal Peptide Ameliorate Symptoms in a Model of Chronic Multiple Sclerosis

Multiple sclerosis (MS) is a severe debilitating disorder characterized by progressive demyelination and axonal damage of the central nervous system (CNS). Current therapies for MS inhibit the immune response and demonstrate reasonable benefits if applied during the early phase of relapsing–remitting MS (RRMS) while there are no treatments for patients that progress neither to the chronic phase nor for the primary progressive form of the disease. In this manuscript, we have studied the therapeutic efficacy of a cell and gene therapy strategy for the treatment of a mouse model of chronic MS [myelin oligodendrocyte glycoprotein (MOG)-induced experimental autoimmune encephalomyelitis (EAE)]. We used allogenic mesenchymal stem cells (MSCs) as a therapeutic tool and also as vehicle to deliver fully processed 3.3-kDa vasoactive intestinal peptide (VIP) to the peripheral immune organs and to the inflamed CNS. Intraperitoneal administrations of MSCs expressing VIP stopped progression and reduced symptoms when administered at peak of disease. The improvement in clinical score correlated with diminished peripheral T-cell responses against MOG as well as lower inflammation, lower demyelination, and higher neuronal integrity in the CNS. Interestingly, neither lentiviral vectors expressing VIP nor unmodified MSCs were therapeutic when administer at the peak of disease. The increased therapeutic effect of MSCs expressing VIP over unmodified MSCs requires the immunoregulatory and neuroprotective roles of both VIP and MSCs and the ability of the MSCs to migrate to peripheral lymph organs and the inflamed CNS.

Use of zinc-finger nucleases to knock out the WAS gene in K562 cells: a human cellular model for Wiskott-Aldrich syndrome

Mutations in the WAS gene cause Wiskott-Aldrich syndrome (WAS), which is characterized by eczema, immunodeficiency and microthrombocytopenia. Although the role of WASP in lymphocytes and myeloid cells is well characterized, its role on megakaryocyte (MK) development is poorly understood. In order to develop a human cellular model that mimics the megakaryocytic-derived defects observed in WAS patients we used K562 cells, a well-known model for study of megakaryocytic development. We knocked out the WAS gene in K562 cells using a zinc-finger nuclease (ZFN) pair targeting the WAS intron 1 and a homologous donor DNA that disrupted WASP expression. Knockout of WASP on K562 cells (K562WASKO cells) resulted in several megakaryocytic-related defects such as morphological alterations, lower expression of CD41ɑ, lower increments in F-actin polymerization upon stimulation, reduced CD43 expression and increased phosphatidylserine exposure. All these defects have been previously described either in WAS-knockout mice or in WAS patients, validating K562WASKO as a cell model for WAS. However, K562WASPKO cells showed also increased basal F-actin and adhesion, increased expression of CD61 and reduced expression of TGFβ and Factor VIII, defects that have never been described before for WAS-deficient cells. Interestingly, these phenotypic alterations correlate with different roles for WASP in megakaryocytic differentiation. All phenotypic alterations observed in K562WASKO cells were alleviated upon expression of WAS following lentiviral transduction, confirming the role of WASP in these phenotypes. In summary, in this work we have validated a human cellular model, K562WASPKO, that mimics the megakaryocytic-related defects found in WAS-knockout mice and have found evidences for a role of WASP as regulator of megakaryocytic differentiation. We propose the use of K562WASPKO cells as a tool to study the molecular mechanisms involved in the megakaryocytic-related defects observed in WAS patients and as a cellular model to study new therapeutic strategies.

Prostaglandin E2-induced IL-23p19 subunit is regulated by cAMP-responsive element-binding protein and C/AATT enhancer-binding protein β in bone marrow-derived dendritic cells

We reported previously that prostaglandin E2 (PGE2) up-regulates IL-23 in vitro in bone marrow-derived dendritic cells and in vivo in models of collagen-induced arthritis and inflammatory bowel disease, leading to preferential Th17 development and activity. There is very little information on the molecular mechanisms involved in the PGE2-induced up-regulation of Il23a gene expression. In this study we investigated the signaling pathways and transcription factors involved in the stimulatory effect of PGE2. Although PGE2 does not induce IL-23p19 expression by itself, it synergizes with both extra- and intracellular Toll-like receptor ligands and with inflammatory cytokines such as TNFα. We established that the effect of PGE2 in conjunction with either LPS or TNFα is mediated through the EP4 receptor and the cAMP-dependent activation of both protein kinase A (PKA) and exchange protein activated by cAMP (EPAC). Using the EP4 agonist PGE(1)OH in conjunction with TNFα, we found that PKA-induced phosphorylation of cAMP-response element-binding protein ((P)CREB) and EPAC-induced phosphorylation of C/AATT enhancer-binding protein β ((P)C/EBPβ) mediate the stimulatory effect of PGE2 on IL-23p19 expression. This is the first report of CREB and C/EBPβ involvement in Il23a promoter activation. Mutation within the putative CREB and C/EBP sites combined with in vivo DNA binding (ChIP) assays identified the distal CREB site (-1125) and the two proximal C/EBP sites (-274 and -232) as essential for PKA-activated CREB and EPAC-activated C/EBPβ-induced IL-23p19 expression.

Development of an all-in-one lentiviral vector system based on the original TetR for the easy generation of Tet-ON cell lines

Lentiviral vectors (LVs) are considered one of the most promising vehicles to efficiently deliver genetic information for basic research and gene therapy approaches. Combining LVs with drug-inducible expression systems should allow tight control of transgene expression with minimal side effect on relevant target cells. A new doxycycline-regulated system based on the original TetR repressor was developed in 1998 as an alternative to the TetR-VP16 chimeras (tTA and rtTA) to avoid secondary effects due to the expression of transactivator domains. However, previously described TetR-based systems required cell cloning and/or antibiotic selection of tetracycline-responsive cells in order to achieve good regulation. In the present manuscript we have constructed a dual Tet-ON system based on two lentiviral vectors, one expressing the TetR through the spleen focus forming virus (SFFV) promoter (STetR) and a second expressing eGFP through the regulatable CMV-TetO promoter (CTetOE). Using these vectors we have demonstrated that the TetR repressor, contrary to the reverse transactivator (rtTA), can be expressed in excess to bind and modulate a high number of TetO operons. We have also showed that this dual vector system can generate regulatable bulk cell lines (expressing high levels of TetR) that are able to modulate transgene expression either by varying doxycycline concentration and/or by varying the amount of CTetOE vector genomes per cell. Based on these results we have developed a new all-in-one lentiviral vector (CEST) driving the expression of TetR through the SFFV promoter and the expression of eGFP through the doxycycline-responsive CMV-TetO operon. This vector efficiently produced Tet-ON regulatable immortalized (293T) and primary (human mesenchymal stem cells and human primary fibroblasts) cells. Bulk doxycycline-responsive cell lines express high levels of the transgene with low amount of doxycycline and are phenotypically indistinct from its parental cells.

Cecal ligation puncture procedure

Human sepsis is characterized by a set of systemic reactions in response to intensive and massive infection that failed to be locally contained by the host. Currently, sepsis ranks among the top ten causes of mortality in the USA intensive care units. During sepsis there are two established haemodynamic phases that may overlap. The initial phase (hyperdynamic) is defined as a massive production of proinflammatory cytokines and reactive oxygen species by macrophages and neutrophils that affects vascular permeability (leading to hypotension), cardiac function and induces metabolic changes culminating in tissue necrosis and organ failure. Consequently, the most common cause of mortality is acute kidney injury. The second phase (hypodynamic) is an anti-inflammatory process involving altered monocyte antigen presentation, decreased lymphocyte proliferation and function and increased apoptosis. This state known as immunosuppression or immune depression sharply increases the risk of nocosomial infections and ultimately, death. The mechanisms of these pathophysiological processes are not well characterized. Because both phases of sepsis may cause irreversible and irreparable damage, it is essential to determine the immunological and physiological status of the patient. This is the main reason why many therapeutic drugs have failed. The same drug given at different stages of sepsis may be therapeutic or otherwise harmful or have no effect. To understand sepsis at various levels it is crucial to have a suitable and comprehensive animal model that reproduces the clinical course of the disease. It is important to characterize the pathophysiological mechanisms occurring during sepsis and control the model conditions for testing potential therapeutic agents. To study the etiology of human sepsis researchers have developed different animal models. The most widely used clinical model is cecal ligation and puncture (CLP). The CLP model consists of the perforation of the cecum allowing the release of fecal material into the peritoneal cavity to generate an exacerbated immune response induced by polymicrobial infection. This model fulfills the human condition that is clinically relevant. As in humans, mice that undergo CLP with fluid resuscitation show the first (early) hyperdynamic phase that in time progresses to the second (late) hypodynamic phase. In addition, the cytokine profile is similar to that seen in human sepsis where there is increased lymphocyte apoptosis (reviewed in). Due to the multiple and overlapping mechanisms involved in sepsis, researchers need a suitable sepsis model of controlled severity in order to obtain consistent and reproducible results.

Was cDNA sequences modulate transgene expression of was promoter-driven lentiviral vectors

Abstract The development of vectors that express a therapeutic transgene efficiently and specifically in hematopoietic cells (HCs) is an important goal for gene therapy of hematological disorders. We have previously shown that a 500-bp fragment from the proximal Was gene promoter in a lentiviral vector (LV) was sufficient to achieve more than 100-fold higher levels of Wiskott-Aldrich syndrome protein in HCs than in nonhematopoietic cells (non-HCs). We show now that this differential was reduced up to 10 times when the enhanced green fluorescent protein gene (eGFP) was expressed instead of Was in the same LV backbone. Insertion of Was cDNA sequences downstream of eGFP in these LVs had a negative effect on transgene expression. This effect varied in different cell types but, overall, Was cDNA sequences increased the hematopoietic specificity of Was promoter-driven LV. We have characterized the minimal fragment required to increase hematopoietic specificity and have demonstrated that the mechanism involves Was promoter regulation and RNA processing. In addition, we have shown that Was cDNA sequences interfere with the enhancer activity of the woodchuck posttranscriptional regulatory element. These results represent the first data showing the role of Was intragenic sequences in gene regulation.

Docosahexaenoic acid prevents dendritic cell maturation and in vitro and in vivo expression of the IL-12 cytokine family

Background

Acute and chronic inflammation play essential roles in inflammatory/autoimmune conditions. Protective anti-inflammatory effects of the n-3 fatty acids docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) were reported in animal models of colitis, sepsis, and stroke. Since dendritic cells (DC) represent the essential cellular link between innate and adaptive immunity and have a prominent role in tolerance for self-antigens, we sought to investigate the impact of DHA on DC maturation and proinflammatory cytokine production.

Methods

Murine bone marrow-derived DC were treated with DHA and stimulated with various toll-like receptor (TLR) ligands. Flow cytometry was used to determine the levels of surface maturation markers and endocytic activity. Cytokine expression and secretion were measured by real-time RT-PCR and ELISA assays. PPARγ and NFκB activity in nuclear extracts were determined by binding to specific oligonucleotide sequences using ELISA-based assays. In vivo effects of DHA were assessed in splenic DC from LPS-inoculated mice maintained on a DHA-enriched diet.

Results

DHA maintained the immature phenotype in bone marrow-derived DC by preventing the upregulation of MHCII and costimulatory molecules (CD40, CD80 and CD86) and maintaining high levels of endocytic activity. DHA inhibited the production of pro-inflammatory cytokines, including the IL-12 cytokine family (IL-12p70, IL-23, and IL-27), from DC stimulated with TLR2, 3, 4, and 9 ligands. DHA inhibition of IL-12 expression was mediated through activation of PPARγ and inhibition of NFκBp65 nuclear translocation. DHA exerted a similar inhibitory effect on IL-12 and IL-23 expression in vivo in LPS-inoculated mice maintained on a DHA-enriched diet.

Conclusions

Exposure of bone marrow-derived DC to DHA resulted in the maintenance of an immature phenotype and drastic reduction in proinflammatory cytokine release. DHA inhibited the expression and secretion of the IL-12 cytokine family members (IL-12p70, IL-23 and IL-27), which play essential roles in the differentiation of the proinflammatory Th1/Th17 effector cells. The effect of DHA on IL-12 expression was mediated through activation of PPARγ and inhibition of NFκB. Inhibition of IL-12 and IL-23 expression was also evident in splenic DC from mice fed a DHA-enriched diet, suggesting that dietary DHA acts as an anti-inflammatory agent in vivo.

Hematopoietic-specific lentiviral vectors circumvent cellular toxicity due to ectopic expression of Wiskott-Aldrich syndrome protein

Efficient and safe gene modification of hematopoietic stem cells is a requirement for gene therapy of primary immunodeficiencies such as Wiskott-Aldrich syndrome. However, deregulated expression or ectopic expression in the progeny of transduced nonhematopoietic progenitor cells may lead to unwanted toxicity. We therefore analyzed the effect of ectopic expression of Wiskott-Aldrich syndrome protein (WASp) and the potential benefits of hematopoietic-specific lentiviral vectors (driven by the WAS proximal promoter). Overexpression of WASp by constitutive lentiviral vectors is highly toxic in nonhematopoietic cells because it causes dramatic changes in actin localization and polymerization that result in decreased cell viability, as evidenced by a significant growth disadvantage of WASp-overexpressing nonhematopoietic cells and increased cell death. These toxic effects do not affect cells of hematopoietic origin because, remarkably, we found that WASp cannot be readily overexpressed in T cells, even after multiple vector integrations per cell. The adverse cellular effects found after transduction of nonhematopoietic cells with constitutive lentiviral vectors are overcome by the use of transcriptionally targeted lentiviral vectors expressing WASp, which, at the same time, are efficient tools for gene therapy of WAS as demonstrated by their ability to reconstitute cellular defects from WASp-deficient mouse and human cells. We therefore postulate that transcriptionally regulated lentiviral vectors represent a safer and efficient alternative for the development of clinical protocols of WAS gene therapy.

In vivo delivery of lentiviral vectors expressing vasoactive intestinal peptide complementary DNA as gene therapy for collagen-induced arthritis

OBJECTIVE

Vasoactive intestinal peptide (VIP) has been shown to exert potent immunomodulatory activity, and the use of lentiviral vectors has been found to be an effective means of gene delivery. The present study was therefore undertaken to investigate the feasibility and efficiency of gene therapy using lentiviral vectors expressing VIP (LentiVIP) for the treatment of rheumatoid arthritis (RA).

METHODS

We evaluated the therapeutic potential of the gene therapy strategy in the collagen-induced arthritis (CIA) mouse model, administering the vectors at different phases of the disease. The inflammatory response was determined by measuring the levels of various inflammatory cytokines and chemokines in the joints and serum. The Th1-mediated response was evaluated by determining the proliferative response and cytokine profile of T cells stimulated with autoantigen.

RESULTS

A single intraperitoneal injection of LentiVIP was highly effective in treating CIA. Mice with established, severe arthritis showed complete regression of the disease. The therapeutic effect of LentiVIP was associated with widespread biodistribution of the vector and increased VIP levels, especially in joints and lymphoid organs, and was mediated through a striking reduction of the 2 deleterious components of the disease, i.e., the autoimmune response (self-reactive Th1 cell activity and autoantibody production) and the inflammatory response. LentiVIP treatment also induced the generation and/or activation of CD4+,CD25+,FoxP3+ Treg cells in arthritic mice.

CONCLUSION

Our findings show that in vivo administration of lentiviral vector expressing VIP produces one of the most potent therapeutic effects described so far in any animal model of RA. We propose that VIP gene transfer should be further investigated as a potential novel, effective treatment of RA and other chronic autoimmune disorders.

Efficient lentiviral transduction of Herpesvirus saimiri immortalized T cells as a model for gene therapy in primary immunodeficiencies

Infection of human T lymphocytes with the Herpesvirus saimiri (HVS) yields immortalized T-cell lines (HVS-T) which retain all the phenotypical and functional characteristics of their parental cells. This represents a new experimental model for studying genetic disorders of T lymphocytes. In spite of the efforts of many laboratories, no satisfactory way has been found so far to modify HVS-T cells genetically. We have analyzed the capacity of oncoretroviral (MLV)- and lentiviral (HIV-1)-based vectors pseudotyped with vesicular stomatitis virus glycoprotein (VSVg) to transduce HVS-T cells. HIV-1-derived vectors efficiently transduced HVS-T cell lines, reaching up to 85% of cells expressing the transgene in a single round of infection. MLV-based vectors, on the other hand, were unable to transduce more than 1% of any of the HVS-T cell lines analyzed. Lentiviral-driven gene expression was maintained constant and stable in HVS-T cells for a minimum of 48 days. We also observed that although the lentiviral transduction efficiency achieved on HVS-T cells is lower than that obtained with tumor or primary endothelial cells, it is nevertheless similar to that found with activated primary T cells.

Expression and DNA binding activity of the Ku heterodimer in bladder carcinoma

BACKGROUND

The Ku protein is a tightly associated heterodimer, comprised of 70-kilodalton (kD) and 86-kD subunits, that forms the DNA-dependent protein kinase (DNA-PK) complex together with the 470-kD DNA-PKcs catalytic subunit, and is involved mainly in DNA double-strand breaks (DSBs) repair. The objective of the current study was to investigate the expression and DNA-binding activity of the Ku protein in fresh tissues from patients with bladder carcinoma and to compare it with that in nontumor tissues obtained from the same organ. Moreover, the DNA-binding activity of Ku was assessed after exposure of the tumor cells to 1 or 2 grays (Gy) of X-rays. Furthermore, the level of phosphorylated Ku was analyzed in both the nuclear and cytoplasmic compartment of normal tissue after exposure to 2 Gy of X-rays.

METHODS

The expression and DNA-binding activity of Ku protein were assessed in tumor samples from patients who all were diagnosed with transitional cell carcinoma (TCC) of the bladder using Western blot analysis and the electrophoretic mobility shift assay, respectively.

RESULTS

Enhanced Ku activity and expression were found in tumor tissue compared with normal tissue for each patient. Moreover, variations in Ku activity were found in a dose-dependent manner after the tumor cells were exposed to 1 or 2 Gy of X-rays. A decrease in phosphorylated Ku in the cytoplasm and a parallel increase in the nucleus of normal tissue cells were observed after exposure to X-rays.

CONCLUSIONS

The results of the current study suggest a possible role of Ku in regulating the DNA-PK activity of DSBs repair in bladder tumors.

Expression and DNA binding activity of the Ku heterodimer in bladder carcinoma

BACKGROUND

The Ku protein is a tightly associated heterodimer, comprised of 70-kilodalton (kD) and 86-kD subunits, that forms the DNA-dependent protein kinase (DNA-PK) complex together with the 470-kD DNA-PKcs catalytic subunit, and is involved mainly in DNA double-strand breaks (DSBs) repair. The objective of the current study was to investigate the expression and DNA-binding activity of the Ku protein in fresh tissues from patients with bladder carcinoma and to compare it with that in nontumor tissues obtained from the same organ. Moreover, the DNA-binding activity of Ku was assessed after exposure of the tumor cells to 1 or 2 grays (Gy) of X-rays. Furthermore, the level of phosphorylated Ku was analyzed in both the nuclear and cytoplasmic compartment of normal tissue after exposure to 2 Gy of X-rays.

METHODS

The expression and DNA-binding activity of Ku protein were assessed in tumor samples from patients who all were diagnosed with transitional cell carcinoma (TCC) of the bladder using Western blot analysis and the electrophoretic mobility shift assay, respectively.

RESULTS

Enhanced Ku activity and expression were found in tumor tissue compared with normal tissue for each patient. Moreover, variations in Ku activity were found in a dose-dependent manner after the tumor cells were exposed to 1 or 2 Gy of X-rays. A decrease in phosphorylated Ku in the cytoplasm and a parallel increase in the nucleus of normal tissue cells were observed after exposure to X-rays.

CONCLUSIONS

The results of the current study suggest a possible role of Ku in regulating the DNA-PK activity of DSBs repair in bladder tumors.

Expression and DNA binding activity of the Ku heterodimer in bladder carcinoma

BACKGROUND

The Ku protein is a tightly associated heterodimer, comprised of 70-kilodalton (kD) and 86-kD subunits, that forms the DNA-dependent protein kinase (DNA-PK) complex together with the 470-kD DNA-PKcs catalytic subunit, and is involved mainly in DNA double-strand breaks (DSBs) repair. The objective of the current study was to investigate the expression and DNA-binding activity of the Ku protein in fresh tissues from patients with bladder carcinoma and to compare it with that in nontumor tissues obtained from the same organ. Moreover, the DNA-binding activity of Ku was assessed after exposure of the tumor cells to 1 or 2 grays (Gy) of X-rays. Furthermore, the level of phosphorylated Ku was analyzed in both the nuclear and cytoplasmic compartment of normal tissue after exposure to 2 Gy of X-rays.

METHODS

The expression and DNA-binding activity of Ku protein were assessed in tumor samples from patients who all were diagnosed with transitional cell carcinoma (TCC) of the bladder using Western blot analysis and the electrophoretic mobility shift assay, respectively.

RESULTS

Enhanced Ku activity and expression were found in tumor tissue compared with normal tissue for each patient. Moreover, variations in Ku activity were found in a dose-dependent manner after the tumor cells were exposed to 1 or 2 Gy of X-rays. A decrease in phosphorylated Ku in the cytoplasm and a parallel increase in the nucleus of normal tissue cells were observed after exposure to X-rays.

CONCLUSIONS

The results of the current study suggest a possible role of Ku in regulating the DNA-PK activity of DSBs repair in bladder tumors.

Flow cytometric DNA ploidy, p53, PCNA, and c-erbB-2 protein expressions as predictors of survival in surgically resected gastric cancer patients

In order to determine retrospectively the impact of some cytometric and immunohistochemical parameters on the overall survival of gastric cancer patients treated with surgery alone, paraffin-embedded tumor samples from 137 gastric carcinoma patients undergoing curative resection from 1987-1993 were analyzed by flow cytometry (FCM) and immunohistochemistry (p53, c-erbB-2, and PCNA expression). FCM-derived parameters were DNA ploidy and fraction of S-phase cells (SPF). Multiple regression analysis was applied to determine the prognostic significance of the conventional clinicopathologic findings together with the flow cytometric and immunohistochemical parameters on overall survival. When all parameters were entered simultaneously into the Cox regression model, stage and DNA ploidy (DNA index >1.35) clearly emerged as the only independent prognostic factors. When the stages were analysed separately, the independent prognostic factors resulted DNA ploidy in early stages (I-II) and grading in stage IIIA tumors. For stage IIIB tumors, no independent prognostic factor was found. These results indicate that the DNA ploidy pattern is a valuable predictor of survival in curatively resected gastric cancer patients, especially when less advanced tumors are taken into consideration.