Differential antitumor effects of administration of recombinant IL-18 or recombinant IL-12 are mediated primarily by Fas-Fas ligand- and perforin-induced tumor apoptosis, respectively

Systemic administration of rIL-18 protein to mice significantly suppresses the growth of murine tumor cell lines. The antitumor effect of IL-18 appears to be primarily mediated by asialo GM1+ cells. Since IL-18 enhances Fas ligand (FasL) expression on NK cell lines, the IL-18 antitumor effects could be mediated by FasL-induced cross-linking of Fas and subsequent tumor apoptosis. To address this question, rIL-18 or rIL-12 was administered to animals bearing the CL8-1 melanoma inoculated intradermally into wild type (wt), lymphoproliferation gene (lpr) (Fas deficient), or generalized lymphoproliferative disease gene (gld) (FasL deficient) mice. Although rIL-12 treatment retained significant antitumor effects in gld and lpr mice, those of rIL-18 administration were completely abrogated in gld but not lpr or wt mice. In vitro cytotoxicity was significantly enhanced against NK-sensitive YAC-1 cells and CL8-1 cells by rIL-18 administration to wt mice, but not to gld mice. Furthermore, rIL-18 administration augmented the cytotoxicity of liver lymphocytes harvested from perforin-deficient mice, whereas rIL-12 administration did not. Consistent with the role of this pathway, rIL-18 administration also up-regulates the expression of FasL mRNA in splenocytes. Lysis of CL8-1 cells induced by anti-Fas agonistic Ab was enhanced about 1.4-fold by IFN-gamma, a cytokine that is induced by IL-18 in vitro and in vivo. We conclude that the antitumor effect of IL-18 is exerted predominantly through a Fas-dependent pathway. The perforin pathway, however, appears to be the predominant cytolytic pathway mediating IL-12 antitumor effects.

Immunohistochemical detection of human telomerase reverse transcriptase in normal mucosa and precancerous lesions of the stomach

Telomerase activity confers cell immortality through stabilization of the chromosome, participating in the development of a majority of human cancers. Human telomerase reverse transcriptase (TERT) has been identified as a catalytic subunit of telomerase, and is overexpressed in most gastric carcinomas. We immunohistochemically examined the expression of TERT in normal gastric mucosa and candidate precancerous lesions such as intestinal metaplasia and adenoma. In non-neoplastic gastric mucosa including intestinal metaplasia and normal fundic mucosa, weak but significant expression of TERT was detected in nuclei of epithelial cells located in the lower two-thirds of the glands (wider than the proliferative zone). The telomerase activity was found in a half of gastric adenomas, whose levels of the activity were about 10% of those in gastric carcinomas. TERT protein was expressed in the nuclei of the adenoma cells at moderate levels, that were not necessarily comparable with the telomerase activities. These findings overall suggest that TERT expression may be one of the prerequisites for telomerase activation in an early stage of stomach carcinogenesis.

Effects of high temperature on the emergence and survival of adult Culex pipiens molestus and Culex quinquefasciatus in Japan

The emergence rate and adult survival (longevity) of Japanese strains of Culex pipiens molestus and Culex quinquefasciatus were compared at temperatures of 21, 25, and 30 degrees C. The pupation and emergence rates in both strains were higher at 21 and 25 degrees C than at 30 degrees C. The adult emergence rate, especially in females, was lower in Cx. p. molestus than in Cx. quinquefasciatus. Longevity of females and males was lower in Cx. p. molestus at 25 degrees C and above. The survival of Cx. p. molestus was adversely affected by temperatures of 28 degrees C and higher. High temperature may restrict the distribution of this species. Therefore, if Cx. p. molestus infests the Okinawa region, the likelihood that it will become established is minimal.

Potent antitumor effects mediated by local expression of the mature form of the interferon-gamma inducing factor, interleukin-18 (IL-18)

IL-18 is produced during the acute immune response by macrophages and immature dendritic cells. IL-18 receptors are induced on T cells and NK cells by IL-12 and together they enhance a cellular immune response. We constructed retroviral and adenoviral vectors encoding the mature bioactive murine IL-18 in order to examine their immune and antitumor effects in murine tumor models. Secretion of bioactive IL-18 from murine tumor cells was facilitated by transfecting them with recombinant viral vectors carrying the prepro leader sequence of human parathyroid hormone fused to the 5' end of the mature murine IL-18 cDNA. Direct injection of the IL-18 recombinant adenoviral vector (Ad.PTH.IL-18) into an established MCA205 murine fibrosarcoma completely eradicated tumor in all animals with concomitant induction of protective systemic immunity. Co-administration of systemic IL-12 provided synergistic antitumor effects when combined with peritumoral injections of Ad.PTH.IL-18 without apparent side-effects as we observed with systemic administration of IL-18. Depletion of asialo GM-1+ cells completely abrogated the antitumor effects of Ad.PTH.IL-18, suggesting a major role for NK cells in mediating the anti-tumor effects of IL-18. Peritumoral injection of Ad.PTH.IL-18 was also associated with reduced numbers of CD8+ cells found within the tumor (HBSS versus Ad.PTH.IL-18, P < 0.0001). This suggests that IL-18 could be utilized as an alternative cancer gene therapy especially when combined with systemic administration of IL-12.

Immuno-histochemical detection of human telomerase catalytic component, hTERT, in human colorectal tumor and non-tumor tissue sections

Human telomerase is expressed in germ tissues and in the majority of primary tumors. Cell renewal tissues and some pre-cancerous tissues also have weak telomerase activity. Yet, neither the exact location and frequency of telomerase-positive cells nor the changes in telomerase expression during differentiation or carcinogenesis of individual cells are known. This paper reports on the expression of hTERT (telomerase reverse transcriptase) protein in tumor and non-tumor colorectal tissues by Western blotting and tissue sections by immunohistochemistry using antibodies raised against partial peptides of hTERT. Though telomerase activity and hTERT expression at both mRNA and protein levels were generally higher in tumor part than in non-tumor part, these two were not always correlated: expression of hTERT did not always give rise to high telomerase activity. Colonic carcinoma cell nuclei were stained with anti-hTERT antibodies but not with antigen-preabsorbed antibodies. In normal mucosa, hTERT protein was expressed, though weaker than in carcinoma, in all colonic crypt epithelial cells except those at the tip; the expressing-cell distribution was much wider than that of Ki-67 positive cells which were located at the bottom of the crypt. Isolated crypt contained a significant level of hTERT protein revealed by Western blotting, while having very weak telomerase activity. Telomerase activity was detected in epithelial cells only at the bottom half of the crypt. Specific hTERT-staining was positive in tissue lymphocytes but negative in almost all other stromal cells. It is of interest to see whether a significant level of hTERT expression with low telomerase activity is characteristic of physiologically regenerating tissues containing stem cells. In situ detection of the hTERT protein will permit further analysis of cancer diagnosis and stem cell differentiation.

Effect of antisense human telomerase RNA transfection on the growth of human gastric cancer cell lines

The majority of gastric cancers express high levels of human telomerase template RNA (hTR) that is essential for cellular survival. In this study, we examined whether antisense hTR (ahTR) had a growth inhibitory effect on three gastric cancer cell lines, MKN-1, MKN-28, and TMK-1, through transfection via an ahTR expression vector. Both the ahTR transfected MKN-1 and TMK-1 cells changed morphologically into multinucleate giant cells, and subsequently underwent cell death. Conversely, the ahTR transfected MKN-28 cells survived over 50 PDs in spite of telomere shortening. Surprisingly, high levels of telomerase activity were observed in the telomere-reduced cells. Furthermore, the expression of mRNAs for p21/Waf1/Cip1/Sdi1, IRF-1 and IFN inducible 6-16 was higher in the telomere-reduced cells than in the parental cells. These results suggest overall that the ahTR expression may bring about telomere shorting, leading to cell death or cellular senescence in gastric cancer cells.

Effective cytokine gene therapy against an intracranial glioma using a retrovirally transduced IL-4 plus HSVtk tumor vaccine

To explore the potential for molecular immunotherapies in the treatment of malignant gliomas, we evaluated the efficacy of subcutaneous tumor cell vaccines in the treatment of intracranial 9L tumors, using 9L gliosarcoma cell lines stably transduced with the murine interleukin-4 cDNA (9L-IL4), the herpes simplex virus-thymidine kinase cDNA (9L-Tk) or both (9L-IL4-Tk). The expression of multiple genes from a single transcript was achieved by incorporating internal ribosomal entry site (IRES) cassettes in the retroviral constructs. Subcutaneous immunization of rats with nonirradiated 9L-IL4 cells or 9L-IL4-Tk cells followed by treatment with ganciclovir (GCV) completely protected the animals from a subsequent intracranial challenge with wild-type 9L cells. In contrast, only 50% of animals immunized with 9L-Tk cells and 0% of 9L-neo immunized animals rejected the same challenge with wild-type 9L. More importantly, treatment of established (day 3) intracranial 9L tumors with genetically engineered tumor cells resulted in long-term survival (> 100 days) for 25-43% of 9L-IL4-Tk immunized animals and for 27% of nonirradiated 9L-IL4 immunized animals. In striking contrast, no 9L-Tk, 9L-neo or irradiated 9L-IL4 immunized animals survived for more than 33 days. As a marker of a cellular immune response, splenocytes from nonirradiated 9L-IL4, 9L-Tk or 9L-IL4-Tk immunized animals produced interferon-gamma (IFN-gamma) in greater amounts than those from 9L-neo immunized or Hank's balanced salts solution (HBSS) treated animals when stimulated with wild-type 9L in vitro. Our findings support the use of tumor cell vaccines expressing the IL-4 and HSVtk genes for the treatment of malignant gliomas.

Induction of antitumor immunity by direct intratumoral injection of a recombinant adenovirus vector expressing interleukin-12

Direct intratumoral (i.t.) injection of adenoviruses (Ads) expressing specific immunostimulatory cytokines represents an attractive strategy for the clinical implementation of cytokine gene therapy of cancer. Interleukin-12 (IL-12) is a heterodimeric cytokine produced by antigen-presenting cells and promotes a T helper 1-like immune response. We have constructed an Ad vector (AdCMV-mIL-12) containing both chains of the murine IL-12 (mIL-12) gene linked by an internal ribosomal entry site sequence under the transcriptional control of the cytomegalovirus immediate-early gene promoter, which is able to mediate the transient expression of very high levels of biologically active mIL-12 both in vitro and in vivo. An i.t. injection of 4x10(8) plaque-forming units of AdCMV-mIL-12 resulted in a complete regression of day 7 established subcutaneous MC38 murine adenocarcinomas and MCA205 murine fibrosarcomas. Treated animals rejected a subsequent rechallenge with MC38 and MCA205, respectively, demonstrating the induction of long-lasting antitumor immunity. Specific antitumor cytotoxic T lymphocyte reactivity was detected in splenocytes harvested from treated animals. A significant increase in the numbers of both CD4+ and CD8+ T cells in the AdCMV-mIL-12-infected tumors was observed. Ad-mediated IL-12 gene therapy was also associated with measurable serum levels of mIL-12 and profound changes in the composition of splenic lymphocytes. Taken together, these results demonstrate the feasibility and efficacy of delivering IL-12 directly i.t. using a recombinant adenoviral vector.

Retroviral delivery of viral interleukin-10 into myeloid dendritic cells markedly inhibits their allostimulatory activity and promotes the induction of T-cell hyporesponsiveness

BACKGROUND

Dendritic cells (DC) play critical roles in the initiation and modulation of immune responses and may determine the balance between tolerance and immunity. Viral interleukin-10 (vIL-10), encoded by the Epstein-Barr virus, is highly homologous to the "immunosuppressive" cytokine, mammalian IL-10. It impairs antigen-presenting cell function but lacks certain immunostimulatory properties of mammalian IL-10. We accomplished the following: (1) evaluated the effects of vIL-10 protein on DC phenotype and function, (2) transduced mouse bone marrow-derived DC to express vIL-10, and (3) assessed the impact of transgene expression on DC allostimulatory activity.

METHODS

DC progenitors propagated from bone marrow of B10 (H2b) mice in granulocyte-macrophage colony-stimulating factor plus IL-4 were repeatedly transduced by centrifugation, using retroviral supernatant obtained from the BOSC 23 ecotropic packaging cell line. To evaluate transduction efficiency, DC were transduced with the retroviral vector MFG-enhanced green fluorescence protein as a marker gene. Transgene and key cell surface molecule expression were examined by flow cytometry. The level of vIL-10 gene product in the culture supernatant was quantitated by ELISA. DC function was assessed by evaluation of the ability of DC to induce allogeneic (C3H;H2k) T-cell proliferation and cytotoxic T lymphocytes in primary mixed leukocyte reactions. Secondary mixed leukocyte reactions were used to test for T-cell hyporesponsiveness.

RESULTS

The early addition of vIL-10 protein to cultures inhibited DC maturation and function. vIL-10 gene transfer was achieved with an approximate transduction efficiency of 35 to 40%. Transduced DC expressed vIL-10 at a level of 40 ng/10(6) cells/48 hr. In comparison with controls, vIL-10-transduced cells showed decreased surface expression of major histocompatibility complex class II and costimulatory molecules, reduced ability to stimulate T-cell proliferation and cytotoxic T lymphocyte generation, and potential to induce alloantigen-specific hyporesponsiveness.

CONCLUSIONS

DC can be effectively transduced to express vIL-10 and limit their ability to stimulate in vitro. These genetically engineered antigen-presenting cells may have therapeutic potential to inhibit undesired immune responses to allo- or autoantigens.

New method to measure telomerase activity by transcription-mediated amplification and hybridization protection assay

Telomerase is a ribonucleoprotein complex that uses RNA as a template for the addition of telomeric repeats. The development of the telomeric repeat amplification protocol (TRAP), a sensitive PCR-based assay, has facilitated the detection of telomerase activity in small tissue and tumor samples. Telomerase activity is expected to be a new diagnostic and prognostic marker of human cancer. In this study, we applied a non-PCR-based transcription-mediated amplification (TMA) and hybridization protection assay (HPA) to the measurement of telomerase activity by modification of both primers in TMA. We demonstrated that the modified TMA can detect and measure telomerase activity. TMA/HPA is as sensitive and reproducible as conventional TRAP, but is both faster and easier to perform. Furthermore, we found that TMA/HPA was influenced minimally by TRAP inhibitors that may come from clinical samples. TMA/HPA, which is easy, rapid, and applicable to a high-throughput format, should be clinically useful for the detection and monitoring of telomerase activity.

[Histopathological examination of transurethral electrovaporization of the prostate]

Transurethral electrovaporization of the prostate (TVP) has been devised to eliminate prostatic tissue by electric vaporization and to create a dry coagulation layer beneath to minimize bleeding from the site of TVP. However, vaporization induces degeneration due to thermal coagulation deep in the tissue beneath the vaporized layer, and local tissue damage is thus greater than that caused by the standard transurethral resection of prostate (TURP) loop. Since this results in difficulty with histopathological examination, the percentages of tissue-diagnosable area were determined in sections resected using various vaporization electrodes (Roller Loop, Band & Wedge Loop). The percentage of tissue-diagnosable area was 92.0 +/- 3.3% with the standard TUR loop, 2.4 +/- 0.9% with the Roller Loop, 42.7 +/- 21.1% with the Band Loop, and 39.7 +/- 24.4% with the Wedge Loop. Concerning speed of resection, the best vaporization effect was obtained when the speed of operation was 1/2 or 1/3 that with the standard TUR loop. Since the region in which tissue diagnosis was smaller with the vaporization electrode than with standard TURP, more careful examination was required for diagnosis of incidental cancers. Therefore, postoperative observation by PSA measurement appeared to be important.

Expression of telomerase catalytic component, telomerase reverse transcriptase, in human gastric carcinomas

Telomerase activity is believed to be crucial for cellular immortality, which is considered to participate in the development of a majority of human cancers. Human telomerase reverse transcriptase (TERT) has recently been identified as a catalytic subunit of telomerase. We examined the expression of TERT and other telomerase components such as human telomerase RNA component (hTR, encoded by TERC) and human telomerase-associated protein (TEP1) by reverse transcription-polymerase chain reaction in human gastric carcinomas and non-neoplastic mucosa, in addition to measuring the telomerase activity. Of 20 gastric carcinomas examined, 18 (90%) and 18 (90%) showed increased expression of TERT and higher telomerase activity in comparison with corresponding non-neoplastic mucosa, respectively. Increased expression of hTR/TERC was also observed in 15 (75%) of the gastric carcinomas. Immunohistochemically, strong expression of TERT protein was detected in the nuclei of the tumor cells of all carcinoma tissues, while the expression of TERT in non-neoplastic mucosal cells as well as stromal elements (except lymphocytes) was weak or negative. These findings suggest that increased TERT expression associated with telomerase activity may serve as a novel marker for the diagnosis of stomach cancer.

New brominated and halogen-less derivatives and structure-activity relationship of azaphilones inhibiting gp120-CD4 binding

Novel brominated and halogen-less azaphilone (oxoisochromane) derivatives, 5-bromoochrephilone and dechloroisochromophilone IV, and known derivatives, dechloroisochromophilone III and isorotiorin, were isolated from the culture broth of a producing organism of isochromophilones I and II (azaphilones inhibiting gp120-CD4 binding), Penicillium multicolor FO-2338, fermented in a medium containing potassium bromide. Nineteen azaphilone-related compounds isolated from the above strain and from other fungi were tested for the inhibition of gp120-CD4 binding and the structure-activity relationship is discussed. Consequently, 5-bromoochrephilone is the strongest inhibitor (IC50, 2.5 microM). A halogen atom at C-5, a proton at C-8 and a diene structure in C-3 side chain of 6-oxoisochromane ring are necessary for gp120-CD4 binding.

In situ mRNA hybridization technique for analysis of human telomerase RNA in gastric precancerous and cancerous lesions

Telomerase, the ribonucleoprotein enzyme that elongates telomerase, is repressed in normal somatic cells but is reactivated during tumor progression. The purpose of this study was to investigate the localization of human telomerase RNA (hTR) expression in human gastric precancerous and cancerous lesions by using in situ mRNA hybridization (ISH) with avidin-biotin staining. We also examined telomerase activity in these lesions by using hybridization protection assay connected with a telomeric repeat amplification protocol (TRAP/HPA). Analyzed tissue samples were as follows; 132 cases of chronic atrophic gastritis without intestinal metaplasia, 115 incomplete-type intestinal metaplasias, 40 complete-type intestinal metaplasias, 23 hyperplastic polyps, 23 tubular adenomas and 26 adenocarcinomas. In ISH analysis, high levels of hTR expression were observed preferentially in the nuclei at the single-cell level. hTR-expressing cells in carcinomas and adenomas were significantly more frequent than those of the other lesions (P < 0.001). The expression pattern of hTR in carcinoma and adenoma tissues was heterogeneous and similar intratumor heterogeneity was detected in Ki-67 immunoreactivity. Infiltrating lymphocytes in tissue also exhibited high levels of hTR expression. In TRAP/HPA analysis, carcinomas had significantly more frequent positivity for telomerase activity and a higher level of telomerase activity than the other lesions (P < 0.05). However, the amount of telomerase activity did not parallel the expression level of hTR. Our data suggest that hTR expression increases in the early stages of stomach carcinogenesis and that sufficient synthesis of hTR is a prerequisite for telomerase reactivation in tumorigenesis.

Bone marrow-derived dendritic cells pulsed with a tumor-specific peptide elicit effective anti-tumor immunity against intracranial neoplasms

Although the central nervous system (CNS) is often regarded as an immunologically privileged site, it is well established that specific CNS immunoreactivity can be generated through peripheral vaccination with CNS antigens. Dendritic cells (DC) are potent antigen presenting cells of hematopoietic origin that have emerged as a promising tool for cancer immunotherapy capable of evoking significant anti-tumor immunity when pulsed with tumor-associated peptides. To explore a role for DC-based immunization strategies for the treatment of CNS tumors, we developed a brain tumor model using the C3 sarcoma cell line which expresses the tumor-specific, major histocompatibility complex (MHC) class I-restricted peptide epitope E7(49-57). Syngeneic C57Bl/6 mice receiving intravenous (i.v.) injections of bone marrow-derived DCs pulsed with E7 peptide were effectively protected against a subsequent intracerebral challenge with C3 tumor cells. More importantly, this systemic immunization strategy was effective in a therapy model as 67% of animals (10 of 15) with established (day 7) intracerebral C3 tumors treated with 3 weekly injections of E7 peptide-pulsed DCs achieved a long-term survival (>90 days) while no control animals survived beyond day 41. In vivo depletion of CD8+ cells, but not CD4+ or asialo-GM1+ cells, abrogated the efficacy of E7 peptide-pulsed DC therapy of established tumors, indicating a pivotal role of specific CD8+ T-cell responses in mediating the anti-tumor effect. Our findings support the hypothesis that effective CNS anti-tumor immunoreactivity can be generated with DC-based tumor vaccines.

[Myxoid liposarcoma surrounding non-functioning transplanted kidney after living renal transplantation: a case report]

A 19-year-old male visited our clinic with the complaint of lower abdominal distention, January 1992. He had undergone living renal transplantation from his mother as a donor on June 15, 1988. But the transplanted kidney had become functional loss by chronic rejection 3 years after transplantation. The computed tomography showed huge low density mass around the non-functioning transplanted kidney. En block resection of the tumor and the transplanted kidney was performed. The tumor was pathologically diagnosed as mixoid liposarcoma. It was proved that the tumor cells were derived from recipient cells by the investigation of HLA-DRB1 DNA typing.

Telomerase activity in lesions of the thyroid: application to diagnosis of clinical samples including fine-needle aspirates

The telomerase enzyme is capable of replacing telomeric DNA sequences that are lost at each cell division. It has been suggested that the function of this enzyme is necessary for cells to become immortal, and in concordance with this hypothesis, telomerase activity has been detected in malignant tumor cells, whereas the enzyme is inactive in normal somatic cells. The measurement of this activity in human tissue samples may have diagnostic value, and in this study, we examined whether such a measurement may be useful for the detection of malignant cells within the thyroid. Telomerase activity was assayed using the telomeric repeat amplification protocol and related to the histological diagnosis of thyroid biopsy tissue samples and of cells obtained from the thyroid by fine-needle aspiration (FNA). Extracts from 9 of 11 (82%) carcinoma biopsy tissue samples contained telomerase activity, whereas enzyme activity was detected in only 2 of 14 (14%) benign tissue sample extracts. These two positive cases were subsequently diagnosed as Graves' disease with severe lymphocytic infiltration. Five of six (83.3%) histologically confirmed carcinoma FNA samples were identified by using the telomeric repeat amplification protocol assay, and two samples considered to be suspicious by FNA cytology were also positive. Conversely, only 4 of 48 (8.3%) benign FNA samples had telomerase. These promising data indicate that this sensitive assay could become a useful adjunct to microscopic cytopathology in the detection of cancer cells in small tissue biopsies and in fine-needle aspirates of the thyroid.

Extra-chromosomal telomere repeat DNA in telomerase-negative immortalized cell lines

We found novel extra-chromosomal telomere repeat (ECTR) DNAs in telomerase-negative immortalized KMST-6 cells, by staining these cells with a (TTAGGG)n probe using both cycling oligonucleotide-primed in situ synthesis and by fluorescence in situ hybridization. Relatively small amounts of ECTR DNAs were also observed in telomerase-negative VA13 and SUSM-1 cells, but not observed in telomerase-positive immortalized HeLa cells. The ECTR DNAs existed mainly in the nucleoplasm with a small amount in the cytoplasm. The nucleoplasm ECTR DNAs were co-stained with an antibody directed to the telomeric-repeat binding factor 1 (TRF1), suggesting that they exist as a complex with TRF1. In consistent with these cytological studies, Southern blot analysis showed the existence of small telomere repeat DNAs. The ECTR DNA may provide an insight into the elucidation of the mechanisms responsible for the maintenance of telomeres in telomerase-negative immortalized cells.

A hVti1 homologue: its expression depends on population doubling levels in both normal and SV40-transformed human fibroblasts

A cDNA clone was isolated by differential colony hybridization from a cDNA library prepared from life-extended SV40-transformed human fibroblasts. The clone, tentatively named N-10, was 1272 bp in length coding for 232 amino acids. Northern analysis revealed that the expression level of N-10 was increased in normal senescent and life-extended SV40-transformed fibroblasts than in their young counterparts but was not enhanced by growth arrest. The protein fused to GFP (green fluorescent protein) localized in cytoplasmic granule. Enforced expression of N-10 resulted in premature senescence in young fibroblasts. The deduced amino acid sequence of N-10 was identical to the recently reported hVti1 gene except in one amino acid: Asp24(GAC) was ours and Asn24 (AAC) was reported. Additional base differences were found, so we referred to our sequence as the hVti1 homologue. As hVti1 protein was suggested to be involved in the vesicle transport process, the homologue may be concerned with increased secretion of extracellular matrix and various cytokines associated with cellular senescence.

Novel chromosomal abnormalities identified by comparative genomic hybridization in parathyroid adenomas

The molecular basis of parathyroid adenomatosis includes defects in the cyclin D1/PRAD1 and MEN1 genes but is, in large part, unknown. To identify new locations of parathyroid oncogenes or tumor suppressor genes, and to further establish the importance of DNA losses described by molecular allelotyping, we performed comparative genomic hybridization (CGH) on a panel of 53 typical sporadic (nonfamilial) parathyroid adenomas. CGH is a new molecular cytogenetic technique in which the entire tumor genome is screened for chromosomal gains and/or losses. Two abnormalities, not previously described, were found recurrently: gain of chromosome 16p (6 of 53 tumors, or 11%) and gain of chromosome 19p (5 of 53, or 9%). Losses were found frequently on 11p (14 of 53, or 26%), as well as 11q (18 of 53, or 34%). Recurrent losses were also seen on chromosomes 1p, 1q, 6q, 9p, 9q, 13q, and 15q, with frequencies ranging from 8-19%. Twenty-four of the 53 adenomas were also extensively analyzed with polymorphic microsatellite markers for allelic losses, either in this study (11 cases) or previously (13 cases). Molecular allelotyping results were highly concordant with CGH results in these tumors (concordance level of 97.5% for all informative markers/chromosome arms examined). In conclusion, CGH has identified the first two known chromosomal gain defects in parathyroid adenomas, suggesting the existence of direct-acting parathyroid oncogenes on chromosomes 16 and 19. CGH has confirmed the locations of putative parathyroid tumor suppressor genes, also defined by molecular allelotyping, on chromosomes 1p, 6q, 9p, 11q, 13q, and 15q. Finally, CGH has provided new evidence favoring the possibility that distinct parathyroid tumor suppressors exist on 1p and 1q, and has raised the possibility of a parathyroid tumor suppressor gene on 11p, distinct from the MEN1 gene on 11q. CGH can identify recurrent genetic abnormalities in hyperparathyroidism, especially chromosomal gains, that other methods to not detect.

Enhancement of antitumor immunity by expression of CD70 (CD27 ligand) or CD154 (CD40 ligand) costimulatory molecules in tumor cells

CD70 (CD27 ligand (CD27L)), CD153 (CD30L), and CD154 (CD40L) are members of the tumor necrosis factor family of costimulatory molecules and expressed on the surface of T cells that are important for both T- and B-cell help. We examined the capacity for expression of these tumor necrosis factor family members on tumor cells to induce an antitumor response either in the presence or absence of interleukin 12. Retroviral vectors were constructed that expressed high levels of membrane bound CD70, CD153, or CD154 following infection and selection of the murine tumor lines MCA 207 or TS/A. The genetically modified tumor cells expressing these molecules were able to stimulate splenic cell proliferation, demonstrating that the expressed costimulatory molecules were biologically active. When tested for tumor establishment, the expression of either CD70 or CD154 was able to slow tumor growth. Similarly, CD70 or CD154 were able to induce antitumor immunity at a higher frequency when tested in vaccination and therapy models. CD70 was able to induce antitumor immunity at a level similar to CD80 when tested either in the presence or absence of interleukin 12. Moreover, coexpression of CD70 and CD80 was able to synergize the induction of a higher frequency of antitumor immunity in a vaccination model. Taken together, our results suggest that CD154 and in particular CD70 are able to contribute to the induction of the immune response to tumor in murine models and thus may be of use for human clinical trials.

[Application of antisense human telomerase RNA toward cancer therapy]

We overviewed recent results of anti-tumor effects and inhibition of telomerase activity in tumor cells through antisense human telomerase RNA(hTR). By introducing antisense hTR expression construct into tumor cells, reduction of telomeric DNAs and crisis or cellular senescence occurred in several human cancer cell lines. Antisense oligonucleotides to hTR synthesized with peptide nucleic acids and phosphorothioate deoxyribonucleic acids(PS) also inhibited telomerase activity in vitro. Furthermore, PS antisense hTR had significant effect to decrease tumor size and a number of metastatic nodules in a xenograft human cancer-nude mouse model. Taken together, the telomerase inhibitors targeting to hTR are expected to be novel anti-tumor agents.

[Analysis of expression of human telomerase RNA in gastric precancerous and cancerous lesions by using in situ mRNA hybridization]

We described the localization of human telomerase RNA (hTR) expression in human gastric precancerous and cancerous lesions by using in situ mRNA hybridization. Diffusely high hTR expression was found in all carcinoma and adenoma tissues. Partially high hTR expression was seen in 75% hyperplastic polyps, 47% complete-type intestinal metaplasia and 21% incomplete-type intestinal metaplasia. All chronic gastritis without intestinal metaplasia possessed normal levels of hTR expression. The expression of hTR was heterogeneous and infiltrating lymphoid cells also expressed high levels of hTR expression. Taken together, overexpression of hTR due to stem cell hyperplasia is an early event of carcinogenesis of the stomach.

Spontaneous rupture of the stomach in preschool age children: a report of two cases

The cases of two preschool-age children who suffered spontaneous gastric ruptures are reported herein. The first was a 2-year-old girl with tetralogy of Fallot, transferred to our hospital due to shock. A laparotomy was performed under the diagnosis of gastrointestinal perforation, and two perforations of the posterior wall of the gastric fundus were found. The second case, a 4-year-old girl who had previously experienced an episode of gastric dilatation, was admitted to our department with abdominal distention and vomiting. An abdominal X-ray film revealed a pneumoperitoneum, and an emergency laparotomy was performed, confirming a round rupture in the posterior wall of the stomach. Both patients had a satisfactory postoperative course.