Biomedical subjects

H Tahara

Publications and source records attributed to H Tahara.

At least 19 recordsLinked to original sources

PubMed2001

Cytokine gene therapy for myocarditis by in vivo electroporation.

Cytokines are important pathophysiologic and pathogenic factors in cardiovascular disorders, including viral myocarditis. We attempted to treat viral myocarditis with cytokine gene therapy by transferring an inhibitory cytokine, IL-1 receptor antagonist (IL-1ra) or viral IL-10 (vIL-10), by in vivo electroporation, a new method for gene transfer into muscle. Four-week-old male DBA/2 mice were inoculated intraperitoneally with 10 PFU of encephalomyocarditis virus. Immediately after virus inoculation, an expression plasmid carrying IL-1ra or vIL-10 was injected into tibialis anterior muscles followed by electroporation. Serum levels of IL1ra and vIL-10 reached 10.5 and 2.3 ng/ml, respectively, on day 5, when gene expression reached its peak. Histopathological examination showed that myocardial cellular infiltration was improved in mice treated with IL-1ra or vIL-10 compared with the control group. On day 14 after the onset of myocarditis, transfer of IL1ra or vIL-10 expression plasmid had significantly improved the survival rates of the animals. The expression of TNF-alpha was decreased to 0.60-fold (p < 0.005) and inducible nitric oxide synthase (iNOS) 0.43-fold (p < 0.005) by IL-1ra treatment, and the expression of IFN-gamma in the heart was decreased to 0.35-fold (p < 0.05), and iNOS 0.21-fold (p < 0.005), by vIL-10 relative to the controls. These results show that gene therapy with IL-1ra or vIL-10 expression plasmid was effective in the treatment of viral myocarditis, and in vivo electroporation may be a useful method by which to deliver cytokine therapy in cardiovascular diseases.

Animals↗

PubMed2001

Mammalian and viral IL-10 enhance C-C chemokine receptor 5 but down-regulate C-C chemokine receptor 7 expression by myeloid dendritic cells: impact on chemotactic responses and in vivo homing ability.

The immunosuppressive and anti-inflammatory cytokine IL-10 inhibits the phenotypic and functional maturation of dendritic cells (DC) and has been reported to confer tolerogenic properties on these important professional APC. Here, we exposed murine bone marrow-derived myeloid DC to either mouse (m) or viral (v) IL-10 early during their in vitro generation in response to GM-CSF and IL-4. Both mIL-10 and vIL-10 down-regulated the expression of CCR7 mRNA determined by RT-PCR, while mIL-10 up-regulated the expression of CCR5 transcripts. These changes in CCR7 and CCR5 expression were associated with inhibition and augmentation, respectively, of DC chemotaxis toward their respective agonists, macrophage inflammatory proteins 3beta and 1alpha, while in vivo homing of DC from peripheral s.c. sites to secondary lymphoid tissue of syngeneic or allogeneic recipients was significantly impaired. Anti-mIL-10R mAb reversed the effects of mIL-10 on CCR expression and restored DC homing ability. Retroviral transduction of mIL-10- and vIL-10-treated DC to overexpress transgenic CCR7 partially restored the cells' lymphoid tissue homing ability in allogeneic recipients. However, CCR7 gene transfer did not reinstate the capacity of IL-10-treated DC to prime host naive T cells for ex vivo proliferative responses or Th1 cytokine (IFN-gamma) production in response to rechallenge with (donor) alloantigen. These findings suggest that in addition to their capacity to subvert DC maturation/function and confer tolerogenic potential on these cells, mIL-10 and vIL-10 regulate DC migratory responses via modulation of CCR expression.

Adjuvants, Immunologic↗

PubMed2001

Distinct pattern of p53 phosphorylation in human tumors.

The protein product of the tumor suppressor gene p53 is phosphorylated on multiple residues by several protein kinases. Using a battery of 10 antibodies developed against different phosphorylated and acetylated residues of p53, we compared the pattern of p53 phosphorylation and acetylation in tumor-derived cell lines, tumor samples, and non-neoplastic cells. Irrespective of tumor types or the presence of p53 mutation, phosphorylation and acetylation of p53 was substantially higher in samples obtained from tumor tissues than those found in non-transformed samples. Among the 10 sites analysed, phosphorylation of residues 15, 81, 392, and acetylation were among the more frequent modifications. Analysis of two of the more abundant phosphorylation or acetylation sites on p53 is sufficient to detect 72% of tumor-derived p53 proteins. The distinct pattern of p53 phosphorylation and acetylation in human tumors may offer a new means to monitor the status and activity of p53 in the course of tumor development and progression.

Acetylation↗

PubMed2001

Differential effects of myeloid dendritic cells retrovirally transduced to express mammalian or viral interleukin-10 on cytotoxic T lymphocyte and natural killer cell functions and resistance to tumor growth.

BACKGROUND: Genetic engineering of dendritic cells (DC) to express immunosuppressive molecule(s) offers potential for therapy of allograft rejection and autoimmune disease. Viral (v) interleukin (IL)-10, encoded by the Epstein-Barr virus, is highly homologous to mammalian (m) IL-10, but lacks certain of its T-cell stimulatory activities. Our aim was to evaluate and compare the influence of vIL-10 and mIL-10 gene transfer on the T-cell and natural killer (NK) cell stimulatory activity of DC, and their impact on the growth of transplantable tumors. METHODS: Myeloid DC progenitors, propagated from the bone marrow of C57BL/6J (H2b) mice in granulocyte-macrophage colony-stimulating factor + IL-4, were transduced using retroviral supematant from the BOSC ecotropic packaging cell line. The function of the IL-b gene-modified DC was assessed by examining their ability to induce naive allogeneic T-cell proliferation and cytotoxic T lymphocyte (CTL) generation. MCA205 (H2b) sarcoma cells mixed with either vIL-10-, mIL-10-, or Zeo (control gene)-transduced DC were inoculated intradermally into C57BL/6J (syngeneic) or BALB/cJ (H2d) (allogeneic) recipients, which were monitored for tumor growth. The role of specific host effector cell populations in tumor resistance was determined by antibody depletion. RESULTS: Compared with control gene-modified DC, both vIL-10- and mIL-10-transduced DC, which secreted the transgene product, showed reduced surface expression of MHC class II and costimulatory molecules, and impaired ability to induce T-cell proliferation. vIL-10-transduced DC were also inhibited with respect to CTL induction but did not affect the generation of NK cells. By contrast, mIL-10-transduced DC augmented CTL generation and NK cell activity. In the tumor transplant model, vIL-10-transduced DC enhanced tumor growth both in syngeneic and allogeneic hosts, whereas mIL-10-transduced cells inhibited tumor development. Depletion of CD4+ or CD8+ T cells or NK cells in mice given mIL-10-transduced DC reversed this therapeutic effect. CONCLUSION: mIL-10 gene-modified myeloid DC promote CTL and NK cell-mediated responses and inhibit tumor growth. By contrast, vIL-10-engineered DC, which elicit diminished CTL responses and do not promote NK cell activity, seem to have therapeutic potential for inhibition of T cell-mediated immunity.

Animals↗

PubMed2001

Interleukin 12 gene therapy of cancer by peritumoral injection of transduced autologous fibroblasts: outcome of a phase I study.

A phase I dose-escalation clinical trial of peritumoral injections of interleukin 12 (IL-12)-transduced autologous fibroblasts was performed in patients with disseminated cancer for whom effective treatment does not exist. The goals of this study were to assess the safety and toxicities as well as the efficacy, and ancillarily the immunomodulatory effects, of peritumoral IL-12 gene transfer. Primary dermal fibroblasts cultured from the patients were transduced with retroviral vector carrying human IL-12 genes (p35 and p40) as well as the neomycin phosphotransferase gene (TFG-hIL-12-Neo). Patients received four injections at intervals of 7 days. Nine patients were enrolled in this dose-escalation study, with secreted IL-12 doses ranging from 300 ng/24 hr for the first three patients to 1000, 3000, and 5000 ng/24 hr for two patients in each subsequent dosage level. Although a definite statement cannot be made, there appears to be perturbation of systemic immunity. Also, the locoregional effects mediated by tumor necrosis factor alpha (TNF-alpha) and CD8+ T cells were observed with tumor regression. Treatment-related adverse events were limited to mild to moderate pain at the injection site; clinically significant toxicities were not encountered. Transient but clear reductions of tumor sizes were observed at the injected sites in four of nine cases, and at noninjected distant sites in one melanoma patient. Hemorrhagic necrosis of tumors was observed in two melanoma patients. These data indicate that gene therapy by peritumoral injection of IL-12-producing autologous fibroblasts is feasible, and promising in patients with advanced cancer.

Adult↗

PubMed2001

Viral IL-10-induced immunosuppression requires Th2 cytokines and impairs APC function within the allograft.

Previous reports demonstrated that retroviral mediated gene transfer of viral IL-10 (vIL-10) prolongs allograft survival by decreasing donor-specific cytotoxic T lymphocyte precursor (CTLp) and IL-2-secreting helper T lymphocyte precursor (HTLp) frequency within graft-infiltrating cells (GIC). This report now shows that vIL-10 efficacy is dependent on CD4(+) T cells, suggesting that immunosuppression may involve a switch from a Th1 to a Th2 alloresponse. In support of this, anti-IL-4 or anti-murine IL-10 (anti-mIL-10) mAbs, but not anti-IFN-gamma mAb, administered at the time of vIL-10 gene transfer prevents enhanced graft survival. Because Th switching involves APC function, GIC were examined for their ability to present alloantigen. GIC from vIL-10-treated grafts were shown to be mostly of recipient (CBA) origin, yet were unable to elicit alloproliferative responses from donor type (C57BL/6) or third party (BALB/c) responders. The inability of vIL-10-treated GIC to stimulate the MLR was not due to the generation of negative regulatory cells or the production of immunosuppressive cytokines such as IL-4, mIL-10, or TGFbeta. Using fractionated GIC subpopulations, the number of recipient type cells in the allografts was modestly reduced by vIL-10 gene transfer, while maintaining both APC phenotype and alloantigen presenting function. Conversely, after vIL-10 gene transfer, donor type GIC were unable to participate in direct alloantigen presentation. Therefore, local immunosuppression induced by vIL-10 gene transfer is CD4 T cell and IL-4 and mIL-10 dependent, and impairs direct alloantigen presentation through an alteration of donor type APC function.

Animals↗

PubMed2001

Bone resorption associated with uncoupling of osteoclastic and osteoblastic activities in adult T cell leukemia with hypercalcemia: case report.

A 64-year-old woman with adult T cell leukemia (ATL) was admitted to our hospital with severe hypercalcemia. The serum calcium level was elevated to 14.9 mg/dl. Biochemical parameters for bone formation including serum osteocalcin (bone Gla protein, BGP) and alkaline phosphatase (ALP) were normal. The serum levels of tartrate-resistant acid phosphatase (TRAP), a parameter for bone resorption, were increased (4.6 KAU). The serum level of parathyroid hormone-related protein (PTHrP) was elevated (343 pmol/l). The cytokines with stimulatory effects on bone resorption, such as interleukin (IL)-1alpha, IL-1beta, IL-6, and tumor necrosis factor-alpha, were not detected. Serum Ca levels, PTHrP levels, and TRAP levels decreased with the decrease in ATL cells after chemotherapy, while serum BGP levels and ALP levels increased. On the 29th hospital day, ATL cells began to increase again. Then serum PTHrP levels, Ca levels, and TRAP levels increased, while serum BGP levels and ALP levels decreased. A marked excessive bone resorption with suppressed bone formation (uncoupling) occurred in this patient. The ATL cells produced not only PTHrP but also IL-1alpha and IL-1beta. These results suggest that PTHrP may act as a humoral factor and IL-1 may act as a local factor in bone metabolism of ATL patients.

Bone Resorption↗

PubMed2001

Post-pubertal mucinous cystadenoma of the pancreas.

A 14-year-old patient with a mucinous cystadenoma of the pancreas (MCAP) is presented. She presented with a palpable left-sided abdominal mass and underwent a left hemipancreatectomy. MCAP occurs mostly in middle-aged women, and no post-pubertal cases have been reported to date in the English literature.

Adolescent↗

PubMed2001

Potent antitumor effects of intra-arterial injection of fibroblasts genetically engineered to express IL-12 in liver metastasis model of rat: no additional benefit of using retroviral producer cell.

Interleukin-12 (IL-12) mediates significant antitumor effects in animal models but associated with dose-dependent toxicity in human. To achieve local expression of IL-12 at the tumor site without systemic toxicity, we performed intra-arterial administration of fibroblasts genetically engineered to produce IL-12 protein with or without retrovirus (CRIP- IL-12 or 3T3-IL-12) in liver metastasis model. Rat breast cancer cells ( MADB - 106) were injected into the portal vein of syngeneic Fisher rats on day 0, and fibroblasts were injected into the hepatic artery on day 7. On day 21, liver weight and number of liver tumors were examined. As controls, CRIP cells expressing retrovirus carrying lacZ marker gene (CRIP-lacZ) or saline (Hanks balanced salt solution, HBSS) were injected. Administration of CRIP-IL-12 significantly reduced tumor metastasis in liver measured by number of foci (CRIP- IL-12: 45.2 +/- 36.7, CRIP-lacZ: >250, HBSS: >250, P<.05) and by liver weight (CRIP-IL-12: 13.0+/-2.5 g, CRIP-lacZ: 30.4+/-8.5 g, HBSS: 26.0+/-7.6 g, P<.05). 3T3-IL-12, which produced only IL-12 protein but not IL-12 retrovirus, also had significant antitumor effects equivalent to CRIP-IL-12. Intra-arterial injection of IL-12--producing fibroblasts into the liver may be an effective therapy for liver tumors reducing systemic toxicity, and could be developed for clinical application.

3T3 Cells↗

PubMed2001

In vivo electroporation-mediated transfer of interleukin-12 and interleukin-18 genes induces significant antitumor effects against melanoma in mice.

Direct intratumoral transfection of cytokine genes was performed by means of the in vivo electroporation as a novel therapeutic strategy for cancer. Plasmid vectors carrying the firefly luciferase, interleukin (IL)-12 and IL-18 genes were injected into established subcutaneous B16-derived melanomas followed by electric pulsation. When plasmid vectors with Epstein--Barr virus (EBV) nuclear antigen 1 (EBNA1) gene were employed, the expression levels of the transgenes were significantly higher in comparison with those obtained with conventional plasmid vectors. In consequence of the transfection with IL-12 and IL-18 genes, serum concentrations of the cytokines were significantly elevated, while interferon (IFN)-gamma also increased in the sera of the animals. The IL-12 gene transfection resulted in significant suppression of tumor growth, while the therapeutic effect was further improved by co-transfection with IL-12 and IL-18 genes. Repetitive co-transfection with IL-12 and IL-18 genes resulted in significant prolongation of survival of the animals. Natural killer (NK) and cytotoxic T lymphocyte (CTL) activities were markedly enhanced in the mice transfected with the cytokine genes. The present data suggest that the cytokine gene transfer can be successfully achieved by in vivo electroporation, leading to both specific and nonspecific antitumoral immune responses and significant therapeutic outcome.

Animals↗

PubMed2001

Putative parathyroid tumor suppressor on 1p: independent molecular mechanisms of tumorigenesis from 11q allelic loss.

Multiple endocrine neoplasia type 1 (MEN1) gene was identified to be a tumor suppressor that encodes menin, playing an important role in the development of MEN1-associated tumors. Somatic MEN1 gene mutations also were detected in sporadic non-MEN1 endocrine tumors. Frequent loss of chromosomal arm 1p has been reported in parathyroid adenomas, suggesting the existence of putative tumor-suppressor genes on 1p. In this study, we performed allelotyping of chromosomes 1p and 11q on 60 sporadic parathyroid adenomas. Thirteen of 48 (27%) informative tumors had allelic loss on 1p, and 18 of 50 (36%) had allelic loss on 11q. Ten of 18 tumors with 11q allelic loss successfully completed the sequence of the MEN1 gene coding region and splice junctions, and 3 of 10 (30%) tumors had no somatic mutation, indicating that other putative tumor-suppressor genes on 11q may contribute to their tumorigenesis. Frequency of allelic losses on 1p was significantly higher in tumors without 11q allelic losses (7 of 11 informative tumors [64%]) than in tumors with 11q allelic losses (3 of 17 informative tumors [18%]) by chi-square test (P = 0.0131; chi-square = 6.152). These observations suggested that putative tumor-suppressor genes locate on 1p, and pathways of their tumorigenesis are independent from inactivation of tumor-suppressor genes on 11q.

Adenoma↗

PubMed2001

Effect of insulin resistance on serum paraoxonase activity in a nondiabetic population.

Paraoxonase is a high-density lipoprotein (HDL)-bound esterase that hydrolyzes various organophosphorus compounds and protects low-density lipoprotein (LDL) against accumulation of lipid peroxides. Paraoxonase activity is strongly affected by the polymorphism of the paraoxonase gene (PON1) at position 192. In addition, the enzyme activity shows a great variation within each genotype, although the underlying mechanism is unknown. Because paraoxonase activity is decreased in subjects with type 2 diabetes mellitus who have insulin resistance, we investigated the association between paraoxonase activity and insulin resistance in a nondiabetic population. The subjects were 237 healthy Japanese adults with fasting plasma glucose less than 7.0 mmol/L. Paraoxonase activity was measured using paraoxon as a routine substrate. Insulin resistance was assessed by homeostasis model assessment index (HOMA index). Paraoxonase activity was affected by HDL level. To reduce the effect of HDL on paraoxonase, paraoxonase activity/HDL ratio was used. When the subjects were divided into tertiles by HOMA index, the subjects with higher HOMA values had higher paraoxonase/HDL ratios, although the 3 groups were comparable in age, gender and the PON1 genotype distribution. Paraoxonase/HDL ratio showed significant positive correlations not only with HOMA index, but also with body mass index, waist-to-hip ratio (WHR), whereas it correlated inversely with age at borderline significance. Multiple regression analysis indicated that the association between HOMA index and paraoxonase/HDL ratio was significant and independent of PON1 genotype, age, and adipocity. The positive association between HOMA index and HDL-corrected enzyme activity was again significant when the enzyme activity was measured with diazoxon as an alternative substrate. These results suggest that insulin resistance or hyperinsulinemia is a factor contributing to the intragenotype variability of paraoxonase activity in a population without overt hyperglycemia.

Adult↗

PubMed2001

Suppression of T(h)1 cell activation and prevention of autoimmune diabetes in NOD mice by local expression of viral IL-10.

Insulin-dependent diabetes mellitus in the NOD mouse model is caused by the T cell-mediated autoimmune destruction of pancreatic beta cells. Viral IL-10 (vIL-10), encoded in the Epstein-Barr virus genome, shares many of the anti-inflammatory properties of cellular IL-10, but lacks its immunostimulatory properties. In the present study, we generated transgenic (Tg) NOD mice in which vIL-10 was produced exclusively in pancreatic islets and investigated the effect of vIL-10 on the development of diabetes. The accumulation of lymphocytes around islets was more prominent, but the invasive insulitis decreased in the vIL-10 Tg mice. The incidence of diabetes was markedly reduced in the vIL-10 Tg mice, in clear contrast to the accelerated diabetes seen in the murine IL-10 Tg NOD mice. IL-12p40 and IFN-gamma mRNA levels were decreased in pancreata of the vIL-10 Tg mice, although CD4 mRNA level was markedly increased. These results suggest that locally produced vIL-10 induced leukocyte migration, but inhibited the activation of T(h)1, probably through suppressing the production of IL-12. They indicate that vIL-10 may well be superior to cellular IL-10 in the treatment of autoimmune diabetes. The vIL-10 Tg NOD mice should provide a useful tool for understanding the differential action of vIL-10 versus cellular IL-10.

Animals↗

PubMed2001

Impact of insulin resistance and nephropathy on homocysteine in type 2 diabetes.

OBJECTIVE: To assess the impacts of insulin resistance and renal function on plasma total homocysteine (tHcy) levels in patients with type 2 diabetes with a wide range of nephropathy. RESEARCH DESIGN AND METHODS: Plasma tHcy levels were measured using the enzyme immunoassay method in 75 patients with type 2 diabetes and compared with those in 54 healthy control subjects. Insulin sensitivity indexes were assessed in patients with type 2 diabetes by hyperinsulinemic-euglycemic clamp using artificial pancreas. RESULTS: Plasma tHcy levels and their log-translormed values (log tHcy) were significantly higher in all patients with diabetes than in control subjects (tHcy, 12.0 +/- 0.7 [SE] vs. 8.7 +/- 0.3 micromol/l, P < 0.0001; log tHcy, 1.040 +/- 0.021 vs. 0.920 +/- 0.016 micromol/l, P < 0.0001). Plasma tHcy levels in patients with diabetes were significantly increased according to degree of nephropathy (P < 0.0001). On simple regression analyses, log tHcy correlated with insulin sensitivity indexes (r = -0.319, P = 0.005) as well as creatinine clearance (r = 0.634, P < 0.0001) in all patients with diabetes. Multiple regression analyses showed that insulin sensitivity indexes (beta = -0.245) as well as creatinine clearance were independent contributors to log tHcy in all patients with diabetes (R2 = 0.750, P < 0.0001). For the 59 patients with diabetes with creatinine clearance >60 ml/min, insulin sensitivity indexes were also shown to be a significant contributor to log tHcy (beta = -0.438, R2 = 0.561, P < 0.001). CONCLUSION: Insulin resistance and renal function are independent determinants of tHcy levels in patients with type 2 diabetes.

Blood Glucose↗

PubMed2001

Glycemic control is a predictor of survival for diabetic patients on hemodialysis.

OBJECTIVE: To investigate the impact of glycemic control on the survival of diabetic subjects with end-stage renal disease (ESRD) starting hemodialysis treatment. RESEARCH DESIGN AND METHODS: This single-center prospective observational study enrolled 150 diabetic ESRD subjects (109 men and 41 women; age at hemodialysis initiation, 60.5 +/- 10.2 years) at start of hemodialysis between January 1989 and December 1997. The subjects were divided into groups according to their glycemic control level at inclusion as follows: good HbA1c <7.5%, n = 93 (group G), and poor HbA1c > or = 7.5%, n = 57 (group P); and survival was followed until December 1999, with a mean follow-up period of 2.7 years. RESULTS: Group G had better survival than group P (the control group) (P = 0.008). At inclusion, there was no significant difference in age, sex, systolic blood pressure (SBP), BMI, cardio-to-thoracic ratio (CTR) on chest X-ray, and serum creatinine (Cre) or hemoglobin (Hb) levels between the two groups. After adjustment for age and sex, HbA1c was a significant predictor of survival (hazard ratio 1. 133 per 1.0% increment of HbA1c, 95% CI 1.028-1.249, P = 0.012), as were Cre and CTR. CONCLUSIONS: Good glycemic control (HbA1c <7.5%) predicts better survival of diabetic ESRD patients starting hemodialysis treatment.

Blood Glucose↗

PubMed2001

[A case of renal oncocytoma with synchronous contralateral renal cell carcinoma].

A case of bilateral, synchronous renal cell carcinoma and oncocytoma is reported. The patient was a 70-year-old woman. Computed tomographic scan revealed bilateral low density masses, which had a diameter of approximately 4 cm (right kidney), and 2.5 cm (left kidney). We suspected bilateral renal cell carcinomas, and performed, right nephrectomy and left enucleation of the tumor. Pathological diagnosis was right renal cell carcinoma and left oncocytoma. To our knowledge only 5 previous cases of renal cell carcinoma associated with oncocytoma have been reported in Japan. Two cases were metachronous and three cases were unilateral and synchronous. This is the first reported case of bilateral, synchronous renal cell carcinoma and oncocytoma.

Adenoma, Oxyphilic↗

PubMed2001

Expression of telomeric repeat binding factor 1 and 2 and TRF1-interacting nuclear protein 2 in human gastric carcinomas.

Telomeric repeat binding factor 1 (TRF1) and 2 (TRF2) may play key roles in the maintenance of telomere function. TRF1 negatively regulates telomere elongation, while TRF2 protects the chromosome ends by inhibiting end-to-end fusions. We examined the expression of TRF1 and TRF2 in 20 gastric carcinomas by reverse transcription polymerase chain reaction and then analyzed the relation with telomerase activity and other telomerase components such as human telomerase reverse transcriptase (TERT), human telomerase RNA component (hTR), human telomerase-associated protein (TEP1) and TRF1-interacting, ankyrin-related ADP-ribose polymerase (tankyrase) as well as TRF1-interacting nuclear protein 2 (TIN2). Of 20 gastric carcinomas examined, 10 (50%) and 12 (60%) expressed TRF1 and TRF2 at higher levels than did non-neoplastic mucosa, respectively. No obvious correlation was observed between TRF1 expression and telomerase activity or expression of TERT, hTR and TEP1. Carcinomas with high TRF1 expression expressed significantly higher levels of tankyrase and TIN2 than did those with low TRF2 expression (p<0.05). The telomerase activities and the levels of TERT, hTR and TEP1 showed tendency to be lower in tumors expressing TRF1 at low levels, although it was not significant. On the other hand, carcinomas with short telomere length (shorter than 2 Kbp) expressed significantly stronger telomerase activities and higher TRF1 expression (p<0.05) and tended to express TRF2 and TIN2 at higher levels than those with long telomere length. The results suggest that gastric carcinomas with short telomeres need high levels of telomerase activity and large quantity of TRFs and TIN2, whereas those with long telomeres do not require high levels of telomerase activity and telomere associated proteins.

Aged↗

PubMed2000

Rapid generation of potent and tumor-specific cytotoxic T lymphocytes by interleukin 18 using dendritic cells and natural killer cells.

We hypothesized that antitumor-specific immunity, which is induced by interleukin (IL) 18 treatment in murine tumor models, is promoted by enhancing natural killer (NK)-mediated destruction of tumor and delivery to dendritic cells (DCs). These activated and antigen-pulsed DCs then critically and optimally induce an adoptive immune response, positioning IL-18 as an important bridge between the innate and adoptive immune response. The effect of IL-18 added to cultures of live tumor cells (MCA205, a mouse sarcoma cell line), NK cells, DCs, and T cells was assessed. When recombinant (r) mIL-18 protein was added to this culture, potent NK cytolytic activity with subsequent generation of CTLs was observed in a dose-dependent manner. Without introduction of either rmIL-18 or NK cells into this culture, systemic cytolytic activity was significantly decreased. Following the absence of direct contact of either NK cells or DCs with other cells in this cooperative coculture system using transwell, the systemic cytolytic activity of both NK cells and CTLs was greatly suppressed. The cytolysis mediated by effector cells harvested after completion of the culture was primarily restricted to MHC class I and highly specific for the tumor cells used in the coculture. Furthermore, we examined the efficiency in the induction of cytolytic T cells of other established IFN-gamma inducing T-cell growth factors, IL-2, and IL-12 in this culture system and compared them with that mediated by IL-18. Neither IL-2 nor IL-12 induced tumor-specific cytolytic T cells to the same degree as that mediated by IL-18. Efficacy of this system in induction of tumor-specific CTLs was also observed in the system using MC38 adenocarcinoma cells. These results are consistent with the notion that IL-18 induces tumor-specific immunity through enhancing NK activity, which in turn mediates tumor cell death and activates and primes DCs.

Adenocarcinoma↗