Identification of TOMM34, which shows elevated expression in the majority of human colon cancers, as a novel drug target

In an attempt to isolate potential molecular targets for diagnosis, treatment and/or prevention of colorectal cancer (CRC), we have been analyzing expression profiles of clinical samples from CRC patients using genome-wide cDNA microarray. Among the genes up-regulated frequently in colorectal tumors, we here focused on TOMM34 (34 kDa-translocase of the outer mitochondrial membrane). Immunohistochemical staining revealed significant accumulation of TOMM34 protein in CRC tissues compared with their corresponding non-cancerous mucosae. Transfection of colon cancer HCT116 cells with short-interfering RNA (siRNA) specific to TOMM34 effectively suppressed its expression and drastically inhibited cell growth. These findings suggest that TOMM34 is involved in the growth of cancer cells, and may contribute to the development of novel anticancer drugs and/or diagnosis for CRC.

Inhibition of tumor growth with antiangiogenic cancer vaccine using epitope peptides derived from human vascular endothelial growth factor receptor 1

PURPOSE

Antiangiogenic therapy is now considered to be one of promising approaches to treat various types of cancer. In this study, we examined the possibility of developing antiangiogenic cancer vaccine targeting vascular endothelial growth factor receptor 1 (VEGFR1) overexpressed on endothelial cells of newly formed vessels in the tumor.

EXPERIMENTAL DESIGN

Epitope-candidate peptides were predicted from the amino acid sequence of VEGFR1 based on their theoretical binding affinities to the corresponding HLAs. The A2/Kb transgenic mice, which express the alpha1 and alpha2 domains of human HLA-A*0201, were immunized with the epitope candidates to examine their effects. We also examined whether these peptides could induce human CTLs specific to the target cells in vitro.

RESULTS

The CTL responses in A2/Kb transgenic mice were induced with vaccination using identified epitope peptides restricted to HLA-A*0201. Peptide-specific CTL clones were also induced in vitro with these identified epitope peptides from peripheral blood mononuclear cells donated by healthy volunteers with HLA-A*0201. We established CTL clones in vitro from human peripheral blood mononuclear cells with HLA-A*2402 as well. These CTL clones were shown to have potent cytotoxicities in a HLA class I-restricted manner not only against peptide-pulsed target cells but also against target cells endogenously expressing VEGFR1. Furthermore, immunization of A2/Kb transgenic mice with identified epitope peptides restricted to HLA-A*0201 was associated with significant suppression of tumor-induced angiogenesis and tumor growth without showing apparent adverse effects.

CONCLUSIONS

These results strongly suggest that VEGFR1 is a promising target for antiangiogenic cancer vaccine and warrants further clinical development of this strategy.

Experience with laparoscopic splenectomy for ABO-incompatible living renal transplantation without plasmapheresis

A 25-year-old male, blood type A, was admitted to our hospital for renal transplantation from his father of AB blood type. Before transplant, we performed laparoscopic splenectomy. The serum anti-B antibody titer fell from 1:8 to 1:2. Therefore, plasmapheresis was not performed. The total ischemic time was 80 minutes. Five immunosuppressive agents, including tacrolimus, mycophenolate mofetil, prednisolone, basiliximab, and deoxyspergualine, were administered in the initial period. On the 47th day, value of cytomegalovirus antibody, which was routinely measured, became positive. Hence, we administered ganciclovir, with a fall in antibody. Sixty-five days after transplant, he was discharged with a serum creatinine of 1.0 mg/dL. We concluded that it was possible to perform ABO-incompatible renal transplantation with no need for plasmapheresis or rituximab.

Identification of TOMM34, which shows elevated expression in the majority of human colon cancers, as a novel drug target

In an attempt to isolate potential molecular targets for diagnosis, treatment and/or prevention of colorectal cancer (CRC), we have been analyzing expression profiles of clinical samples from CRC patients using genome-wide cDNA microarray. Among the genes up-regulated frequently in colorectal tumors, we here focused on TOMM34 (34 kDa-translocase of the outer mitochondrial membrane). Immunohistochemical staining revealed significant accumulation of TOMM34 protein in CRC tissues compared with their corresponding non-cancerous mucosae. Transfection of colon cancer HCT116 cells with short-interfering RNA (siRNA) specific to TOMM34 effectively suppressed its expression and drastically inhibited cell growth. These findings suggest that TOMM34 is involved in the growth of cancer cells, and may contribute to the development of novel anticancer drugs and/or diagnosis for CRC.

Body fat mass and lean mass as predictors of survival in hemodialysis patients

A higher body mass index (BMI) is a predictor of better survival in hemodialysis patients, although the relative importance of body fat and lean mass has not been examined in the dialysis population. We performed an observational cohort study in 808 patients with end-stage renal disease on maintenance hemodialysis. At baseline, fat mass was measured by dual-energy X-ray absorptiometry and expressed as fat mass index (FMI; kg/m2). Lean mass index (LMI) was defined as BMI minus FMI. During the mean follow-up period of 53 months, 147 deaths, including 62 cardiovascular (CV) and 85 non-CV fatal events, were recorded. In univariate analysis, LMI was not significantly associated with CV or non-CV death, whereas a higher FMI was predictive of lower risk for non-CV death. Analyses with multivariate Cox models, which took other confounding variables as covariates, indicated the independent associations between a higher LMI and a lower risk of CV death, as well as between a higher FMI and a lower risk of non-CV death. These results indicate that increased fat mass and lean mass were both conditions associated with better outcomes in the dialysis population.

Identification of secernin 1 as a novel immunotherapy target for gastric cancer using the expression profiles of cDNA microarray

Despite the discovery of multiple TAAs, only a limited number is available for clinical application, particularly against epithelial malignancies. In this study we searched for novel TAAs using expression profiles of gastric cancer examined with cDNA microarray, and identified the SCRN1 gene as a candidate. SCRN1 was confirmed to be expressed in five out of seven gastric cancers with semiquantitative RT-PCR. With Northern blot analysis, it was detected abundantly in the testis and ovary, but it was barely detectable in 14 other normal human adult organs. Colony formation assay revealed that its augmented expression is associated with promoted cell growth. As these expression profiles and functional features of SCRN1 appeared to be compatible with the characteristics of the hypothesized ideal TAAs, we examined whether SCRN1 protein contains antigenic epitope peptides restricted to HLA-A*0201. We synthesized the candidate peptides derived from SCRN1, and tried to induce CTLs with each peptide. The CTL clones were successfully induced with a peptide SCRN1-196 (KMDAEHPEL), and they lyzed not only the peptide-pulsed targets but also the tumor cells expressing both SCRN1 and HLA-A*0201 endogenously. These results strongly suggest that SCRN1-196 is an epitope peptide restricted to HLA-A*0201. Furthermore, we synthesized an anchor-modified peptide SCRN1-9 V (KMDAEHPEV), in which leucine at position 9 was substituted for valine to increase the binding affinity to the HLA-A*0201 molecules. The CTL clones induced by SCRN1-9 V also recognized tumor cells expressing its natural SCRN1 protein endogenously. These results strongly suggest that SCRN1 is a novel TAA and these peptides, both native and modified, may be applicable for cancer vaccines to treat gastric cancer.

G-Quadruplex stabilization by telomestatin induces TRF2 protein dissociation from telomeres and anaphase bridge formation accompanied by loss of the 3′ telomeric overhang in cancer cells

Inhibition of telomerase activity by telomerase inhibitors induces a gradual loss of telomeres, and this in turn causes cancer cells to enter to a crisis stage. Here, we report the telomerase inhibitor telomestatin, which is known to stabilize G-quadruplex structures at 3' single-stranded telomeric overhangs (G-tails), rapidly dissociates TRF2 from telomeres in cancer cells within a week, when given at a concentration that does not cause normal cells to die. The G-tails were dramatically reduced upon short-term treatment with the drug in cancer cell lines, but not in normal fibroblasts and epithelial cells. In addition, telomestatin also induced anaphase bridge formation in cancer cell lines. These effects of telomestatin were similar to those of dominant negative TRF2, which also causes a prompt loss of the telomeric G-tails and induces an anaphase bridge. These results indicate that telomestatin exerts its anticancer effect not only through inhibiting telomere elongation, but also by rapidly disrupting the capping function at the very ends of telomeres. Unlike conventional telomerase inhibitors that require long-term treatments, the G-quadruplex stabilizer telomestatin induced prompt cell death, and it was selectively effective in cancer cells. This study also identifies the TRF2 protein as a therapeutic target for treating many types of cancer which have the TRF2 protein at caps of the telomere DNA of each chromosome.

Effects of viral interleukin 10 introduced by in vivo electroporation on arthrogen-induced arthritis in mice

OBJECTIVE

Viral interleukin 10 (vIL-10) has a variety of immunomodulatory properties. We examined the applicability of vIL-10 gene transfer to the treatment of mice with arthrogen-collagen-induced arthritis (CIA), which is induced by anti-type II collagen antibodies.

METHODS

One day after anti-type II collagen antibodies were injected into mice, 400 microg of plasmid DNA expressing vIL-10 (pCAGGS-vIL-10) was injected into the bilateral tibialis anterior muscles followed by in vivo electroporation consisting of four 50-ms electric pulses of 100 V (pCAGGS-vIL-10 mice). pCAGGS (400 microg) was similarly injected into control mice (pCAGGS mice).

RESULTS

We observed high serum vIL-10 levels in the pCAGGS-vIL-10 mice, but no vIL-10 was detected in the serum of the pCAGGS mice. Using quantitative real-time polymerase chain reaction, we observed that the ratios of IL-6, tumor necrosis factor-a, and IL-1beta transcripts to those of G6PDH in the joints were significantly lower in the pCAGGS-vIL-10 mice than in the pCAGGS mice (p < 0.05). The pCAGGS-vIL-10 mice showed significant therapeutic effects: the severity of the macroscopic arthritis was significantly suppressed from Days 5 to 21 (p < 0.0001), and the histologically observable development of arthritis was also suppressed in these mice on Day 21 (p < 0.0001).

CONCLUSION

These results demonstrated that pCAGGS-vIL-10 gene transfer by in vivo electroporation suppressed arthrogen-CIA.

[Genome analysis and cancer therapy]

Application of the human genome information would lead to the development of novel diagnostic methods and innovative therapies against cancer. In this article, two aspects of such application are reviewed; 1) genomic diagnosis for predicting efficacy and side effects associated with the administration of the anti-cancer drugs, 2) exploration of novel cancer associated gene products using genome-wide gene-expression profiling. Successful examination on genetic information of the patients/tumors would lead to the establishment of the "personalized" medicine which could be an ideal situation for the cancer patients treated with the chemotherapeutic drugs. Furthermore, the finding of tumor associated antigens lead to the development of not only new diagnostic methods but also novel therapeutic modalities including cancer vaccine. Some of the successful efforts are referred and discussed.

Intrathymic inoculation of donor HLA class I-derived peptide generates donor-specific CD4+CD25+ regulatory T cells

CD4(+)CD25(+) regulatory T cells are selected in the thymus to control autoreactive thymic escapees preventing autoimmunity that cannot be achieved by negative selection or deletion alone, thus playing an important role in the maintenance of immunological homeostasis. Not only significant in preventing autoimmunity, CD4(+)CD25(+) regulatory T cells have also been shown to be involved in allograft tolerance in organ transplantation. We have formerly introduced two lines of HLA class I transgenic mice to elucidate the role of HLA class I molecules in transplantation biology. Using a heterotopic cardiac transplantation model, we show herein that intrathymic inoculation of donor HLA class I-derived synthetic peptide results in the generation of CD4(+)CD25(+) regulatory T cells, which induce graft specific tolerance without any preconditioning of the recipient or use of immunosuppressive drugs. This study provides evidence of the novel therapeutic potential of CD4(+)CD25(+) regulatory T cells for clinical transplantation.

Ring finger protein 43 as a new target for cancer immunotherapy

We have performed genome-wide exploration by using cDNA microarray profiling, and successfully identified a new tumor-associated antigen (TAA) that can induce potent cytotoxic T lymphocytes (CTLs) specific to tumor cells. In our preceding study, we identified multiple new genes by using gene expression profiling with a genome-wide cDNA microarray containing 23,040 genes. Among them, we selected RNF43 (ring finger protein 43) as a promising candidate for a TAA expressed by colon cancer cells. In this study, we examined whether the RNF43 protein contains antigenic epitope peptides restricted to HLA-A*0201 or HLA-A*2402. The CTL clones were successfully induced with stimulation by using the peptides binding to HLA-A*0201 (ALWPWLLMA and ALWPWLLMAT) and HLA-A*2402 (NSQPVWLCL), and these CTL clones showed the cytotoxic activity specific to not only the peptide-pulsed targets but also the tumor cells expressing RNF43 and respective HLAs. Lytic activities mediated by two HLA-A2-restricted epitopes were marginal, whereas tumor lysis mediated by the HLA-A24 epitope was clearly better. These findings might be caused by the poor natural presentation of RNF43-11(IX) and RNF43-11(X) by tumors or poor T-cell receptor avidity for these specific epitopes. These results strongly suggest that RNF43 is a new TAA of colon cancer. Furthermore, these results also suggest that our strategy might be a promising one to efficiently discover clinically useful TAAs.

A model of prediction system for adverse cardiovascular reactions by calcineurin inhibitors among patients with renal transplants using gene-based single-nucleotide polymorphisms

The application of pharmacogenomic information to diagnostic assays is expected to improve the prediction of drug efficacy and toxicity, leading to appropriate therapeutic regimens for individual patients. Cardiovascular events are common and severe adverse drug reactions (ADRs) among transplant patients treated with calcineurin inhibitors (CNIs). We conducted case-control association studies using 50,947 gene-based single-nucleotide polymorphisms (SNPs) to identify genetic variations that might be associated with cardiovascular risk factors in 72 renal transplant recipients with CNI therapy. The overall incidence of cardiovascular events was 13.9% (10/72) among patients receiving cyclosporine or tacrolimus; arrhythmias in six patients (8.3%), ischemic heart diseases in two patients (2.8%), and heart failure in two patients (2.8%). On the basis of results of the genome-wide association studies, we attempted to establish a scoring system to predict individual risks for cardiovascular toxicity of cyclosporine and tacrolimus. Estimation of the predictive performance was carried out by the use of internal leave-one-out cross-validation test. When we combined arrhythmia, ischemic heart disease and heart failure cases as subjects with a cardiotoxicity phenotype, nine of ten ADR patients and 50 of 62 non-ADR patients were correctly classified into the respective categories using the top eight SNPs. In addition, the proportion of individuals in the control population (n=246) with scores over the cut-off (11.0%) was close to the cardiovascular ADR frequency (8.3%) among renal transplant patients in the previous clinical study. Our results open the possibility that prediction of CNI-induced cardiovascular complications can lead to better prognosis and quality of life among kidney-transplant patients, and to improved immunosuppressive regimens.

Cancer gene therapy using in vivo electroporation of Flt3-ligand

Dendritic cells (DCs) are potent antigen-presenting cells which play pivotal roles in immunological response. The clinical application of DCs induced from peripheral monocytes in vitro has been initiated as a promising immuno-logical therapy against cancer. If the same type of immuno-stimulator could be achieved without in vitro manipulation, it might be very convenient in clinical settings. In this study, we performed systemic gene transfer of Flt3L using in vivo electroporation of Flt3L plasmid DNA (Flt3L-IVE) in pretibial muscles in order to determine the effects on DCs in situ. After Flt3L-IVE, Flt3L was detected in the serum for 10 days after IVE at significant levels. The peak concentration of 5326+/-920 pg/ml in the serum was observed 4 days after Flt3L-IVE. The number of DCs was significantly increased and showed highly co-stimulatory molecule expressions both in spleen and bone marrow after Flt3L-IVE compared to those of control groups. Immunohistochemical evaluation revealed that not only DCs but also CD8 and CD4 positive cells were significantly infiltrated into the local tumor site compared with those of control and remained in the tumor 21 days after a single Flt3L-IVE. However, anti-tumor effects of Flt3L-IVE were not significant in the MCA205 established tumor. Most of the tumor infiltrating DCs had immature phenotype. Only a small number of DCs in the peripheral areas had the mature phenotype. These results suggest that Flt3L gene transfer using in vivo electroporation could mobilize DCs into tumor site. Additional means to induce maturation of these DCs could have a positive impact on anti-tumor effects of this strategy.

Identification of immunoglobulin superfamily 11 (IGSF11) as a novel target for cancer immunotherapy of gastrointestinal and hepatocellular carcinomas

We previously performed gene expression profile analyses of 20 intestinal-type gastric cancers, and identified a set of genes whose expression levels were elevated in cancer tissues compared to their corresponding non-cancerous tissues. In the present study we focused on the immunoglobulin superfamily 11 gene (IGSF11). Its expression was also elevated in colorectal cancers and hepatocellular carcinomas as well as intestinal-type gastric cancers. Northern blot analysis showed that it was expressed abundantly in testis and ovary. These data suggest that IGSF11 is a good candidate of cancer-testis antigen. Furthermore, suppression of IGSF11 by siRNA retarded the growth of gastric cancer cells. To investigate the possibility of clinical application of peptide vaccine to IGSF11, we synthesized candidate epitope peptides for IGSF11 and tested whether the peptides elicit IGSF11-specific CTL. As a result, we successfully established oligo-clonal CTL by stimulation with IGSF11-9-207 (ALSSGLYQC). In addition, we also established additional CTL using IGSF11-9V (ALSSGLYQV), anchor-modified peptides of IGSF11-9-207. These peptides showed IGSF11-specific cytotoxic activity in an HLA-A*0201-restricted fashion, suggesting that these peptides may be applicable for cancer immunotherapy. These findings have provided a novel insight into carcinogenesis of the stomach, colon and liver, and will be helpful for the development of novel therapeutic strategies to a wide range of human cancers.

Rationale for antiangiogenic cancer therapy with vaccination using epitope peptides derived from human vascular endothelial growth factor receptor 2

Angiogenesis is a critical mechanism for tumor progression. Multiple studies have suggested that tumor growth can be suppressed if tumor angiogenesis can be inhibited using various types of antiangiogenic agents. Recent studies in mouse systems have shown that tumor angiogenesis can also be inhibited if cellular immune response could be induced against vascular endothelial growth factor receptor 2 (VEGFR2), which is one of the key factors in tumor angiogenesis. In this study, we examined the possibility of developing this novel immunotherapy in clinical setting. We first identified the epitope peptides of VEGFR2 and showed that stimulation using these peptides induces CTLs with potent cytotoxicity in the HLA class I-restricted fashion against not only peptide-pulsed target cells but also endothelial cells endogenously expressing VEGFR2. In A2/Kb transgenic mice that express alpha1 and alpha2 domains of human HLA-A*0201, vaccination using these epitope peptides in vivo was associated with significant suppression of the tumor growth and prolongation of the animal survival without fatal adverse effects. In antiangiogenesis assay, tumor-induced angiogenesis was significantly suppressed with the vaccination using these epitope peptides. Furthermore, CTLs specific to the epitope peptides were successfully induced in cancer patients, and the specificities of the CTLs were confirmed using functional and HLA-tetramer analysis. These results in vitro and in vivo strongly suggest that the epitope peptides derived from VEGFR2 could be used as the agents for antiangiogenic immunotherapy against cancer in clinical settings.

Effect of imatinib (STI571) on metastatic gastrointestinal stromal tumors: report of a case

The prognosis for advanced gastrointestinal stromal tumor (GIST) is poor. However, recent reports from Europe have described the effects of imatinib against metastatic GIST. We herein report the case of a Japanese patient treated with imatinib for advanced GIST. Imatinib at 400 mg daily was given to an adult with multiple liver and peritoneal metastases 17 months after undergoing a GIST resection. The sum of the diameter of all target lesions decreased from 37.7 to 10.9 cm at 6 months. Tinnitus (grade 2), which has not been reported elsewhere as an adverse effect, developed at 2 months. However, it did not require any treatment. Other adverse effects, nausea (grade 2) and anemia (grade 2), resolved spontaneously. Our results are consistent with previous reports that show imatinib to be effective for the treatment of metastatic GIST, and also suggest that imatinib at 400 mg daily for more than 7 months is well tolerated in Japanese adults.

Phase I study of autologous tumor vaccines transduced with the GM-CSF gene in four patients with stage IV renal cell cancer in Japan: clinical and immunological findings

We produced lethally irradiated retrovirally GM-CSF-transduced autologous renal tumor cell vaccines (GVAX) from six Japanese patients with stage IV renal cell cancer (RCC). Four patients received GVAX ranging from 1.4 x 10(8) to 3.7 x 10(8) cells on 6-17 occasions. Throughout a total of 48 vaccinations, there were no severe adverse events. After vaccination, DTH skin tests became positive to autologous RCC (auto-RCC) in all patients. The vaccination sites showed significant infiltration by CD4(+) T cells, eosinophils, and HLA-DR-positive cells. The kinetic analyses of cellular immune responses using peripheral blood lymphocytes revealed an enhanced proliferative response against auto-RCC in four patients, and cytotoxicity against auto-RCC was augmented in three patients. T cell receptor beta-chain analysis revealed oligoclonal expansion of T cells in the peripheral blood, skin biopsy specimens from DTH sites, and tumors. Western blot analysis demonstrated the induction of a humoral immune response against auto-RCC. Two of the four patients are currently alive 58 and 40 months after the initial vaccination with low-dose interleukin-2. Our results suggest that GVAX substantially enhanced the antitumor cellular and humoral immune responses, which might have contributed to the relatively long survival times of our patients in the present study.

Dendritic cells might be one of key factors for eliciting antitumor effect by chemoimmunotherapy in vivo

In this study, we demonstrated that chemoimmunotherapy using S-1, a novel oral fluoropyrimidine anticancer drug, combined with lentinan (LNT), a beta (1 --> 3) glucan, was effective in vivo, and we clarified the augmentation of the function of dendritic cells (DCs) in vivo and in vitro. The survival period of Colon-26-bearing mice treated with S-1 + LNT was significantly more prolonged than that of mice treated with S-1 alone (P < 0.05). On the other hand, LNT did not prolong the survival period when combined with S-1 in Colon-26-bearing athymic mice. The frequency of CD86+ DCs infiltrated into Colon-26 was increased in mice treated with S-1 + LNT, and splenic DCs harvested from mice treated with S-1 + LNT showed more potent T-cell proliferation activity than that of DCs from mice treated with S-1 alone (P < 0.05). Furthermore, the activity of cytotoxic T lymphocytes (CTLs) in splenocytes of S-1 + LNT-treated mice was specific and more potent than that of CTLs from mice treated with S-1 alone (P < 0.05). These results suggest that modulation of specific immunity with LNT has a significant role in enhanced antitumor effects through the modification of DC function. We demonstrated that DCs might play an important role in chemotherapy, and the combination therapy of S-1 and LNT presents a promising chemoimmunotherapy, which might lead to better survival for cancer patients.

Adenovirus-mediated transfer of siRNA against survivin induced apoptosis and attenuated tumor cell growth in vitro and in vivo

Gene targeting using short interfering RNA (siRNA) has become a common strategy to explore gene function because of its prominent efficacy and specificity. For the application of siRNA technology to gene therapy, however, still more efficient transduction of siRNA into target cells is needed. In this study, we developed an adenoviral vector harboring a tandem-type siRNA expression unit, in which sense and antisense strands composing the siRNA duplex were separately transcribed by two human U6 promoters. Targeting survivin, an antiapoptotic molecule widely overexpressed in malignancies but not detected in terminally differentiated adult tissues, this type of adenoviral vector (Adv-siSurv) successfully exerted a gene knockdown effect and induced apoptosis in HeLa, U251, and MCF-7 cells. These cancer cells, once infected with Adv-siSurv, displayed remarkably attenuated growth potential, both in vitro and in vivo. Moreover, intratumoral injection of Adv-siSurv significantly suppressed tumor growth in a xenograft model using U251 glioma cells. This novel modality may be a promising tool for cancer therapy.

Antitumor and antiangiogenic effects of interleukin 12 gene therapy in murine head and neck carcinoma model

Interleukin-12 (IL-12) plays a critical role in producing an immune response, as indicated in many ways, e.g., induction of interferon-gamma (IFN-gamma), and augmentation of the cytotoxic activity of resting activated T cells and natural killer (NK) cells. In this study, we examined whether intratumoral injection of a recombinant retrovirus vector expressing IL-12s induce antitumor and antiangiogenic effects in a murine model using a murine head and neck squamous cell carcinoma (NR-S1). In vitro the levels of vascular endothelial growth factor (VEGF) mRNA and protein expression were decreased in IL-12 gene transfected NR-S1 cell. in vivo direct IL-12 gene therapy resulted in significantly remarkable inhibition of tumor growth compared to the control group. The tumor regression by direct IL-12 gene therapy was also associated with decreased vessel density, and apoptosis and increased infiltration of CD8(+) T cells and CD56(+) NK cells in the tumor increased. Also, the number of IFN-gamma expressed cells of spleen cells was increased in the treatment group compared with the control group. These results suggested that direct IL-12 gene therapy appears to be effective in reducing tumor growth by triggering both antiangiogenic effects and an immunological enhancing mechanism through induction of IFN-gamma.

Systemic administration of IL-18 promotes diabetes development in young nonobese diabetic mice

IL-18 is now identified as a pleiotropic cytokine that acts as a cofactor for both Th1 and Th2 cell development. Type 1 diabetes is considered a Th1-type autoimmune disease, and to date, the suppressive effect of exogenous IL-18 on the development of diabetes has been reported in 10-wk-old nonobese diabetic (NOD) mice. In the present study we administered exogenous IL-18 systemically in 4-wk-old NOD mice using i.m. injection of the IL-18 expression plasmid DNA (pCAGGS-IL-18) with electroporation. Contrary to previous reports, the incidence of diabetes development was significantly increased in NOD mice injected with pCAGGS-IL-18 compared with that in control mice. Systemic and pancreatic cytokine profiles deviated to a Th1-dominant state, and the the frequency of glutamic acid decarboxylase-reactive IFN-gamma-producing CD4(+) cells was also high in the IL-18 group. Moreover, it was suggested that the promoting effect of IL-18 might be associated with increased peripheral IL-12, CD86, and pancreatic IFN-inducible protein-10 mRNA expression levels. In conclusion, we demonstrate here that IL-18 plays a promoting role as an enhancer of Th1-type immune responses in diabetes development early in the spontaneous disease process, which may contribute to elucidating the pathogenesis of type 1 diabetes.