Interleukin-12 and B7.1 co-stimulation cooperate in the induction of effective antitumor immunity and therapy of established tumors

Interleukin-12 (IL-12) promotes specific and long-lasting anti-tumor immunity mediated by T cells in a variety of murine tumor models. IL-12 also synergizes with B7.1 (CD80) co-stimulation to induce proliferation and cytokine production by both human and murine T cells in vitro. We evaluated the combined anti-tumor efficacy of IL-12 and B7.1 gene delivery in two apparently poorly immunogenic tumor models (TS/A and MCA207). In both of these models, expression of B7.1 and production of IL-12 in the inoculum led to improved anti-tumor immunity, with up to 80% long-term tumor-free animals (vs 0-20% of mice remaining tumor free when inoculated with either B7.1- or IL-12-transfected tumors alone). Tumor-free mice were capable of rejecting a subsequent rechallenge with the wild-type tumor in 66% of the cases. Cooperativity was dependent upon the level of IL-12 secreted by engineered cells. IL-12 delivery required B7 expression of therapeutic effects to be observed in these models. Vaccines provided at a site distal to a control, non-transfected tumor slowed (TS/A) or abrogated (MCA207) the progression of wild-type tumors. The synergistic anti-tumor effects associated with combined application of B7.1- and IL-12-transfected tumors were partially negated by systemic administration of the CD28-B7.1/B7.2 antagonist CTLA4-Ig or by inoculation with neutralizing antibodies directed against murine interferon-gamma or tumor necrosis factor-alpha, two cytokines elicited in response to IL-12 stimulation. These data support the potential clinical utility of combined gene therapy using IL-12- and B7.1-engineered autologous cells (tumor or fibroblasts) as a vaccine to elicit specific anti-tumor immunity.

Molecular biological observations in gastric cancer

Alterations in the structure and function of oncogenes and tumor suppressor genes, as well as genetic instability at several other genetic foci may be responsible for stomach carcinogenesis. The particular combination of multiple gene changes found in gastric cancer differs depending on the two histological types, strongly indicating that different genetic pathways exist for well differentiated or intestinal type and poorly differentiated or diffuse type gastric cancers. In general, genetic instability, telomerase activity, CD44 abnormal transcripts, and p53 mutation, all of which are common events of two types of gastric cancer, may be involved mainly in the early stage of stomach carcinogenesis, whereas activation of oncogenes and overexpression of the epidermal growth factor-related growth factor system may chiefly confer progression on gastric cancer. A new strategy of molecular diagnosis of gastrointestinal cancer, which has been implemented as a routine service in the Hiroshima University Clinical Laboratory, may provide new opportunities for early cancer diagnosis and more accurate evaluation of prognosis or grade of malignancy.

Strangulated prolapsed ureterocele: a solid vulval mass in a woman

We report a rare case of prolapsed ureterocele in an adult female, which had been identified as a small finger-tip sized orthotopic ureterocele 12 years earlier and recently presented a hard neoplastic mass due to strangulation at the urethra and long-standing inflammation.

Inhibition of cell growth by transforming growth factor beta 1 is associated with p53-independent induction of p21 in gastric carcinoma cells

Cell cycle regulators such as cyclins, cyclin-dependent kinases (cdks) and their inhibitors control the growth of cells. SDI1/CIP1/WAF1/p21 is a potent inhibitor of G1 cdks, whose expression is induced by wild-type p53. To elucidate the mechanism of growth inhibition by transforming growth factor beta 1 (TGFbeta 1), we examined the effect of TGFbeta 1 on the expression of p21, G1 cyclins and cdks by human gastric cancer cell lines. TGFbeta 1 induced p21 expression and subsequently suppressed cdk2 kinase activity, followed by a reduction in phosphorylation of the product of the retinoblastoma tumor suppressor gene in TMK-1 cells, which are responsive to TGFbeta 1. Coimmunoprecipitation analysis demonstrated that TGFbeta 1 increased the level of p21 protein present in complexes with cdk2. In contrast, TGFbeta 1 did not induce p21 in TGFbeta 1-resistant MKN-28 cells. TGFbeta 1 did not affect the levels of p53 mRNA and protein in TMK-1 and MKN-28 cells, which contain mutated p53 genes. These mutated p53 complementary DNAs, when overexpressed, failed to activate transcription from the p21 promoter. Furthermore, TGFbeta 1 caused a reduction in the steady-state level of cyclin A protein concomitantly with inhibition of cdk2 kinase activity in TMK-1 cells. These results suggest that the growth inhibition of tumor cells by TGFbeta 1 is associated with p53-independent induction of p21, subsequent suppression of cdk activity and a decrease in cyclin A protein in TMK-1 cells.

Retrovirus-mediated transfer of viral IL-10 gene prolongs murine cardiac allograft survival

A murine heterotopic, nonvascularized cardiac allograft model was used to examine the effects of the immunosuppressive cytokine, viral IL-10 (vIL-10), delivered by gene transfer on graft rejection. Retroviral-mediated gene transfer and expression of vIL-10 significantly prolonged allograft survival, without conventional systemic immunosuppression, from 12.1 +/- 0.8 days to 39.4 +/- 2.5 days (p < 0.0001). The effect was specific, dose dependent, and restricted to the site of transplantation. PCR analysis demonstrated specific expression of the transferred gene within the allograft. Analysis of the cellular infiltrate in the allografts showed a reduction in T cells and alloantigen-specific cytotoxic T cells and IL-2 producing helper T cells. Thus, the transient local expression of a gene encoding an immunosuppressive protein within a graft can generate local immunosuppression, making gene therapy a viable approach for facilitating transplantation.

Retrovirus-mediated transfer of viral IL-10 gene prolongs murine cardiac allograft survival

A murine heterotopic, nonvascularized cardiac allograft model was used to examine the effects of the immunosuppressive cytokine, viral IL-10 (vIL-10), delivered by gene transfer on graft rejection. Retroviral-mediated gene transfer and expression of vIL-10 significantly prolonged allograft survival, without conventional systemic immunosuppression, from 12.1 +/- 0.8 days to 39.4 +/- 2.5 days (p &lt; 0.0001). The effect was specific, dose dependent, and restricted to the site of transplantation. PCR analysis demonstrated specific expression of the transferred gene within the allograft. Analysis of the cellular infiltrate in the allografts showed a reduction in T cells and alloantigen-specific cytotoxic T cells and IL-2 producing helper T cells. Thus, the transient local expression of a gene encoding an immunosuppressive protein within a graft can generate local immunosuppression, making gene therapy a viable approach for facilitating transplantation.

Regulation of p16CDKN2 expression and its implications for cell immortalization and senescence

p16CDKN2 specifically binds to and inhibits the cyclin-dependent kinases CDK4 and CDK6, which function as regulators of cell cycle progression in G1 by contributing to the phosphorylation of the retinoblastoma protein (pRB). Human cell lines lacking functional pRB contain high levels of p16 RNA and protein, suggesting a negative feedback loop by which pRB might regulate p16 expression in late G1. By a combination of nuclear run-on assays and promoter analyses in human fibroblasts expressing a temperature-sensitive simian virus 40 T antigen, we show that p16 transcription is affected by the status of pRB and define a region in the p16 promoter that is required for this response. However, the effect is not sufficient to account for the differences in p16 RNA levels between pRB-positive and -negative cells. Moreover, p16 RNA is extremely stable, and the levels do not change appreciably during the cell cycle. Primary human fibroblasts express very low levels of p16, but the RNA and protein accumulate in late-passage, senescent cells. The apparent overexpression of p16 in pRB-negative cell lines is therefore caused by at least two factors: loss of repression by pRB and an increase in the number of population doublings.

[Telomerase]

Telomerase is expected to be a powerful tool for cancer diagnosis and cancer chemotherapeutics because of its selective expression exclusively in various cancer tissues at a high frequency (90%) in human somatic tissues. Some precancerous tissues also express telomerase at a high frequency. Normal somatic tissues are mostly telomerase negative. Cancer cells die after a loss of telomerase activity.

Genomic localization of novel candidate tumor suppressor gene loci in human parathyroid adenomas

Only one oncogene, cyclin D1/PRAD1, has an established role in parathyroid tumorigenesis, and parathyroid tumor suppressor genes on chromosome arms 1p and 11q, which still have not been identified, have also been implicated by loss of heterozygosity analysis. To investigate whether other putative tumor suppressor genes are involved in the pathogenesis of parathyroid adenomas, we performed a more comprehensive analysis of allelic losses in these tumors. Using 39 polymorphic markers, we examined each chromosome arm, excluding the short arms of the acrocentric chromosomes. In 25 parathyroid adenomas, frequent loss of heterozygosity, in > 25% of the informative cases, was observed on chromosome arms 6q (30%), 11p (27%), and 15q (35%), in addition to previously reported 1p (30%) and 11q (38%) allelic losses. To more specifically localize the smallest shared regions of molecular genetic deletion, we examined the following chromosomes in greater detail: chromosome 6 (9 additional markers), chromosome 11 (8 additional markers), and chromosome 15 (15 additional markers). The regions most commonly deleted in these tumors were 6q22-23, 6q26-27, 11q13, 15q11-21, and 15q26-qter. All tumors with 11p loss had patterns consistent with monosomy for chromosome 11. These findings provide novel evidence for the existence of tumor suppressor genes on chromosome arms 6q and 15q that contribute commonly to the pathogenesis of parathyroid adenomas.

[Evaluation of area at risk by 123I-BMIPP in patients with acute myocardial infarction]

The purpose of this study was to investigate the detection of area at risk of acute myocardial infarction (AMI) by 123I-BMIPP (BMIPP). 99mTc-tetrofosmin (TF) scintigraphy was performed on 13 patients with AMI with total coronary occlusion. BMIPP scintigraphy was done on the same patients within 1 week after successful reperfusion by direct PTCA. Activity of both tracers was scored in 8 basal, 8 midventricular and 2 apical segments, using a four-point grading system as defect score: 3 = defect, 2 = severely low uptake, 1 = slightly low uptake, 0 = normal. Extent score (ES) was defined as a total number of segment which deteriorated of uptake, and severity score (SS) was defined as a total score of defect score. ES of BMIPP was 6.5 +/- 2.4 and that of TF was 7.5 +/- 2.4. ES of BMIPP was smaller than that of TF. A ratio of BMIPP/TF was 0.86 +/- 0.18. SS of BMIPP was 16.2 +/- 6.0 and that of TF was 19.2 +/- 5.6. SS of TF was larger than that of BMIPP. A ratio of BMIPP/TF was 0.83 +/- 0.18. A correlation of ES and SS between TF and BMIPP was excellent. BMIPP showed ischemic area by culprit lesion and infarct area clearly. We concluded that BMIPP could indicate area at risk.

Effect of 1,25-dihydroxyvitamin D3 on induction of scavenger receptor and differentiation of 12-O-tetradecanoylphorbol-13-acetate-treated THP-1 human monocyte like cells

We investigated the effect of 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) on the expression of scavenger receptors in human monocytic cell line (THP-1 cells) treated for 24 h with 12-O-tetradecanoylphorbol-13-acetate (TPA) which induces their differentiation into macrophages. The capacity to degrade 125I-labeled acetyl low density lipoprotein (LDL) was developed in accordance with macrophage differentiation. The treatment with 10 nM 1,25(OH)2D3 for 72 h inhibited the degradation of acetyl LDL by THP-1 macrophages in a dose-dependent manner, suggesting that 1,25(OH)2D3 inhibits scavenging function in macrophages. In order to clarify the mechanism of its inhibitory effect on degradation of acetyl LDL, we performed the ligand binding assay using 125I-labeled acetyl LDL. Scatchard analysis revealed that 1,25(OH)2D3 decreased the number of scavenger receptors without changing the affinity for acetyl LDL. We next examined the effect of 1,25(OH)2D3 on the expression of scavenger receptor mRNA. The mRNA of type I scavenger receptor was first detected in THP-1 cells 4 days after the treatment with TPA, the mRNA level increased up to 6 days, and then decreased. The treatment with 1,25(OH)2D3 for 72 h dramatically decreased the mRNA levels after the acquisition of macrophage phenotypes as evidenced by nonspecific esterase staining. However, 1,25(OH)2D3 did not affect the activity of nonspecific esterase nor the induction of interleukin-1 beta mRNA by lipopolysaccharide in THP-1 macrophages. These findings suggest that 1,25(OH)2D3 exclusively decreases the expression of scavenger receptors in TPA-induced THP-1 macrophages without affecting the basic cellular functions as macrophages.

Telomerase activity in preneoplastic and neoplastic gastric and colorectal lesions

Recent evidence indicates that telomerase activity may be necessary for cell immortality, which is required for the sustained and indefinite growth of most malignant cells. We analyzed telomerase activity in gastric and colorectal cancers and in gastric and colorectal precancerous lesions to determine whether malignant progression depends on the activation of telomerase and at what stage of carcinogenesis cells have detectable telomerase activity. Telomerase activity was measured by the telomeric repeat amplification protocol assay and was detected in 17 (85%) of 20 primary gastric carcinoma tissues and in 19 (95%) of 20 primary colorectal carcinomas, regardless of tumor staging and histological types. All nodal metastases, peritoneal metastases, and a recurrent gastric cancer tumor were positive. All cell lines established from gastric and colorectal cancers contained telomerase activity. In precancerous lesions, 10 (100%) of 10 colorectal tubular adenomas were telomerase positive, in addition to 3 (23%) of 13 gastric intestinal metaplasias and 1 (50%) of 2 gastric adenomas, whereas the corresponding gastric normal mucosas as well as colorectal mucosas were negative. These results indicate overall that reactivation of telomerase may occur at an early stage of carcinogenesis and may correlate well with malignant progression of gastric cancer. Telomerase activity thus may serve as a powerful additional tool for cancer diagnosis.

[Clinical statistics of 67 cadaveric renal transplantation at the Department of Urology, Kinki University School of Medicine]

A statistic survey was made on the patients undergoing cadaveric renal transplantation between June, 1980 and December, 1993. The total number of patients was sixty-seven. The number of patients per year increased annually. The graft survival rate was 73.8% at 1 year and 63.1% at 5 years. Some transition was seen in immunosuppressive regimens using cyclosporin.

Acute myocardial infarction in a patient with primary coronary dissection and severe coronary vasospasm. A case report

A case of myocardial infarction associated with coronary artery dissection in a thirty-five-year-old woman is reported. An emergent coronary angiogram revealed extensive dissection and thrombosis in the right coronary artery; in addition, severe vasospasm was observed in the left coronary artery on the next day. She was successfully treated with intracoronary thrombolysis and intra-aortic balloon pumping. The patient is alive and well two years after infarction.

Restoration of the cellular senescence program and repression of telomerase by human chromosome 3

Telomeres, at the end of chromosomes, shorten with each cell division, resulting in cellular senescence. Tumor cells, unlike normal somatic cells, express a telomerase that maintains the telomere length. Deletion of a gene(s) on chromosome 3 is common in human renal cell carcinoma (RCC) and reintroduction of a normal chromosome 3 into an RCC immortal cell line restored the program of cellular senescence. The loss of indefinite growth potential was associated with the loss of telomerase activity and shortening of telomeres in the RCC cells with a normal chromosome 3. However, microcell hybrids that escaped from senescence and microcell hybrids with an introduced chromosome 7 or 11 maintained telomere lengths and telomerase activity similar to those of the parental RCC23. Thus, restoration of the cellular senescence program by chromosome 3 is associated with repression of telomerase function in RCC cells.

Increase in expression levels of interferon-inducible genes in senescent human diploid fibroblasts and in SV40-transformed human fibroblasts with extended lifespan

The normal human fibroblast line, TIG-3 which senesces at around 80 population doubling levels (PDLs), expressed interferon (IFN)-inducible genes such as 6-16, 2', 5'-oligoadenylate synthetase (2,5-A) and HLA B7 near the end of the proliferative lifespan. Other normal fibroblast line such as MRC-5 also expressed IFN-inducible genes when senesced. Clones transformed with SV40 T-antigen, which extended their proliferative lifespan by about 20-30 PDLs, also expressed IFN-inducible genes during their extended life. Anti-IFN-beta antibodies added in culture medium repressed the expression of IFN-inducible gene in both normal senescent and life-extended SV40-transformed cells. IFN-beta repressed DNA synthesis in normal TIG-3 and induced IFN-inducible genes in both normal and SV40-transformed TIG-3. Conditioned medium recovered from life-extended SV40-transformed cells contained IFN-beta, but not IFN-alpha, IFN-gamma or TNF-alpha and possessed an activity that inhibited DNA synthesis of young TIG-3. Addition of anti-IFN-beta antibodies into the medium enhanced the serum-induced DNA synthesis of near senescent (91% lifespan completed) TIG-3, while it neither induced DNA synthesis in fully senescent TIG-3 nor extended the proliferative lifespan of TIG-3. These results suggest that normal and SV40-transformed human fibroblasts increase expression of IFN-beta with increasing proliferative age especially near the end of their lifespan resulting in induction of IFN-inducible genes and possibly in growth repression.

[Diagnostic usefulness of myocardial SPECT with 123I-beta-methyl-iodophenyl pentadecanoic acid and 201Tl in unstable angina]

The purpose of this study is whether 123I-BMIPP detects a culprit lesion in patients with unstable angina. Twenty-six patients with unstable angina underwent 123I-BMIPP (BMIPP) and 201Tl (Tl) imaging at rest. BMIPP image was compared with Tl imaging. BMIPP imaging revealed defects or low uptake corresponding to myocardial ischemic areas predicted by coronary angiography in 19 (73.1%) of 26 patients. Tl imaging showed defects or low uptake corresponding to coronary angiographic findings in 14 (53.8%). BMIPP demonstrated significantly less uptake than Tl (p = 0.001). Severity of reduced BMIPP activity was greater than that of Tl (p < 0.001). We concluded that BMIPP imaging was excellent to detecting of culprit lesions in patients with unstable angina. BMIPP SPECT is a sensitive method for detecting myocardium exposed to transient schemia that cannot be detected by Tl imaging.

Overexpression of P-glycoprotein in untreated AFP-producing gastric carcinoma

P-glycoprotein (P-gly), which is responsible for the phenotypic expression of multidrug resistance in cancerous tissue was stained immunohistochemically in previously untreated alpha-fetoprotein (AFP)-producing (n = 20) and nonproducing gastric cancers (n = 20). P-gly, AFP, and carcinoembryonic antigen(CEA) were stained in formalin-fixed paraffin-embedded tissue sections immunohistochemically using the monoclonal antibody JSB-1, anti-AFP, and anti-CEA, respectively. DNA ploidy pattern was determined by Fluorescence Activated Cell Sorter (FACS) analyzer. P-gly was significantly overexpressed in AFP producing gastric cancers (60%) than in AFP nonproducing ones (20%) (P < 0.01). When the result of P-gly staining was analyzed among the AFP-positive cases, P-gly positivity did not emerge either as a significant prognostic factor or as a predictor of the metastatic potentiality of the tumor. The intrinsic overexpression of P-gly in AFP producing gastric cancers proves its biological and morphological similarities to hepatocellular carcinoma. The significantly (P < 0.05) higher incidence of P-gly in diploid tumors indicate that expression of this phenotype might be related to the differentiation of the tumor. P-gly was overexpressed in AFP producing gastric carcinoma and the existing drug resistance, frequent recurrence, and poor prognosis might be explained by presence of P-gly in this carcinoma.

Inhibitors of cGMP-dependent protein kinase block senescence induced by inactivation of T antigen in SV40-transformed immortal human fibroblasts

Immortal human fibroblasts isolated following transfection with thermolabile simian virus 40 T antigen lost division potential upon shift up in temperature due to heat inactivation of the antigen. Such cells showed a concomitant change in the distribution of a mortality marker, mortalin, from a juxtanuclear cap like distribution of immortal cells to a uniform cytosolic distribution of mortal cells. We made an attempt to modulate the above inducible system of cellular senescence using various protein kinase inhibitors. Among the indolocarbazole type inhibitors tested, only KT5823, defined as a specific inhibitor of cGMP-dependent protein kinase, blocked the loss of division potential as determined by cell growth and colony forming ability. This inhibitor also prevented the above change in mortalin distribution due to temperature shift. In addition, the isoquinoline sulfonamide derivatives H8, H9, H88 and H89, all shown to inhibit cGMP-dependent protein kinase, suppressed the senescence. Inhibitors specific to other types of protein kinases, protein phosphatases or tyrosine kinases tested had no effect. Since there was no difference between the effective and non-effective inhibitors in their effects on cell cycle progression, cell cycle arrest by itself cannot account for the above phenomenon. These results suggest that a signaling pathway possibly mediated by cGMP-dependent protein kinase is involved in the induction of cellular senescence.

Cancer immunotherapy of established tumors with IL-12. Effective delivery by genetically engineered fibroblasts

IL-12 is a heterodimeric cytokine produced by macrophages, mitogen stimulated- or EBV infected-B lymphocytes, keratinocytes, and probably dendritic cells, with important immunoregulatory functions in vitro and in vivo. It directly stimulates activated NK and T cells to produce high levels of IFN-gamma, enhances their cytolytic activity, and promotes maturation of Th1 cells as well as IL-2-activated B cells. We have tested paracrine delivery of IL-12 using autologous or allogeneic fibroblasts engineered to secrete high levels of IL-12 to treat established tumors. Injection of IL-12-engineered fibroblasts at the site of an established (day 8) MCA207 sarcoma could efficiently eliminate or suppress tumor growth in a dose-dependent manner, requiring delivery of &gt; 150 ng/kg/dose of bioactive IL-12. Weekly inoculations for 3 wk could also be used to effectively treat a day 4 sarcoma located intradermally in the opposite flank (80% protection using autologous fibroblasts), resulting in long-term protective antitumor immunity. In less immunogenic tumors (MCA102, MC38), 7-day established lung metastases could be significantly reduced (p = 0.001) following IL-12 delivery by fibroblasts and systemic administration of low doses of IL-2. Histologic findings included a mixed infiltrate of CD4+ and CD8+ T effectors and macrophages in the regressing sarcoma on day 21. In a day 41 MCA207 sarcoma locally injected in situ, similar findings were observed. No lymphoid hyperplasia or tissue necrosis were noted in liver, spleen, or lungs in mice receiving repeated inocula of IL-12-engineered fibroblasts. Tests of liver and renal function monitored during the repetitive weekly treatments were within the normal range. IL-12-engineered fibroblasts thus seem to serve as a safe and efficient means to deliver IL-12 in these three tumor models.

Viral interleukin 10 (IL-10), the human herpes virus 4 cellular IL-10 homologue, induces local anergy to allogeneic and syngeneic tumors

After the cloning of murine cytokine synthesis inhibitory factor, it was recognized that a homologous open reading frame was encoded within the Epstein-Barr virus (human herpes virus 4). This viral protein has now been termed viral interleukin 10 (vIL-10) to reflect its protein sequence homology to "cellular" IL-10 (cIL-10, either murine or human IL-10). It is now widely accepted that vIL-10 shares many functions with cIL-10, principally, the ability to enhance survival of newly infected B cells and to diminish the production of IFN-gamma and IL-2 during ongoing immune reactions. The immunomodulatory effect of locally secreted vIL-10 and murine IL-10 (mIL-10) was examined in tumor models using CL8-1 (a BL6 melanoma cell line transfected with the H-2Kb class I gene) in syngeneic animals. Although parental BL6 tumor cells grow in immunocompetent syngeneic hosts, CL8-1 are rejected. To achieve local secretion of vIL-10, we generated vIL-10 retroviral vectors. While nontransduced CL8-1 cells (1 x 10(4)) failed to grow when injected intradermally in C57BL/6 mice, CL8-1 cells (1 x 10(4)) transduced with vIL-10 formed palpable tumors and eventually killed 80% of injected animals. Suppression of tumor rejection was also noted when CL8-1 tumors with or without vIL-10 transfection were admixed with syngeneic vIL-10-transfected fibroblasts and inoculated. Since the in vitro proliferation of the tumor was not altered after transduction with the vIL-10 gene and injection of vIL-10-transduced CL8-1 does not affect the rejection of nontransduced CL8-1 inoculated at a distant site, local vIL-10 secretion appears to suppress the process of immune rejection of the target cells in a dose-dependent manner. Similar results were observed for the H-2b MCA105 sarcoma tumor model in allogeneic BALB/c mice (H-2d). Although all animals that received nontransfected MCA105 rapidly rejected these tumors, MCA105 sarcomas transfected with vIL-10 remained palpable for up to 37 d. The local immunosuppressive effect of gene-delivered vIL-10 could be neutralized by anti-human IL-10 monoclonal antibody or could be reversed by the systemic administration of IL-2 or IL-12. In marked contrast, mIL-10 transfection of CL8-1 significantly suppressed tumor growth and frequently led to the rejection of tumor. Similar results were obtained for the murine tumor cell lines MCA102.(ABSTRACT TRUNCATED AT 400 WORDS)

Cancer immunotherapy of established tumors with IL-12. Effective delivery by genetically engineered fibroblasts

IL-12 is a heterodimeric cytokine produced by macrophages, mitogen stimulated- or EBV infected-B lymphocytes, keratinocytes, and probably dendritic cells, with important immunoregulatory functions in vitro and in vivo. It directly stimulates activated NK and T cells to produce high levels of IFN-gamma, enhances their cytolytic activity, and promotes maturation of Th1 cells as well as IL-2-activated B cells. We have tested paracrine delivery of IL-12 using autologous or allogeneic fibroblasts engineered to secrete high levels of IL-12 to treat established tumors. Injection of IL-12-engineered fibroblasts at the site of an established (day 8) MCA207 sarcoma could efficiently eliminate or suppress tumor growth in a dose-dependent manner, requiring delivery of > 150 ng/kg/dose of bioactive IL-12. Weekly inoculations for 3 wk could also be used to effectively treat a day 4 sarcoma located intradermally in the opposite flank (80% protection using autologous fibroblasts), resulting in long-term protective antitumor immunity. In less immunogenic tumors (MCA102, MC38), 7-day established lung metastases could be significantly reduced (p = 0.001) following IL-12 delivery by fibroblasts and systemic administration of low doses of IL-2. Histologic findings included a mixed infiltrate of CD4+ and CD8+ T effectors and macrophages in the regressing sarcoma on day 21. In a day 41 MCA207 sarcoma locally injected in situ, similar findings were observed. No lymphoid hyperplasia or tissue necrosis were noted in liver, spleen, or lungs in mice receiving repeated inocula of IL-12-engineered fibroblasts. Tests of liver and renal function monitored during the repetitive weekly treatments were within the normal range. IL-12-engineered fibroblasts thus seem to serve as a safe and efficient means to deliver IL-12 in these three tumor models.

Absence of cyclin D1/PRAD1 point mutations in human breast cancers and parathyroid adenomas and identification of a new cyclin D1 gene polymorphism

PRAD1 (cyclin D1) has been implicated in the molecular pathogenesis of a variety of tumors, including parathyroid adenomas, t(11;14)-bearing B-lymphoid tumors, and breast cancer. The sequence of the overexpressed PRAD1 genes has been directly analyzed in only two tumor specimens, a benign parathyroid adenoma and a malignant centrocytic lymphoma. Thus, little is known about PRAD1 sequence in the vast majority of human primary tumors, including breast cancers. Using single-strand conformational polymorphism (SSCP) analysis, we have examined the coding region of the PRAD1 gene in 30 primary breast cancers and 25 parathyroid adenomas. Polymerase chain reaction (PCR)-SSCP analysis of the coding region of exons 1-5 of the PRAD1 gene did not reveal any tumor-specific mutations. During the course of screening for mutations, we found and established the sequence variants of a new DNA polymorphism at codon 241 within exon 4 of the PRAD1 gene. Since this polymorphism is located within the coding region of the PRAD1 gene, it will allow determination of allele-specific expression of the gene and the detection of allele imbalance. At least in breast and parathyroid neoplasms, overexpression of the wild-type PRAD1 sequence, rather than point mutational activation, appears to be the predominant mechanism by which PRAD1 exerts its oncogenic action.

Telomerase activity in human liver tissues: comparison between chronic liver disease and hepatocellular carcinomas

Telomerase activity was examined in 105 frozen samples from human normal liver tissues, chronic liver disease, and hepatocellular carcinoma (HCC). Telomerase activity was positive in 28 of 33 HCC tissues regardless of tumor stage or size. Telomerase was expressed in 15 of 18 differentiated HCC nodules smaller than 3 cm. HCC tissues from all eight hepatitis B virus-positive patients were telomerase positive, while telomerase activity was not detected in normal liver tissues (0 of 4). Weak telomerase activity was only detected in 1 of 22 nontumor liver tissues from HCC patients. Interestingly, in 19 of 38 hepatitis tissues and 6 of 8 cirrhotic liver tissues from apparently cancer-free patients, very weak telomerase activity was detected. These results indicate that the expression of telomerase may play a crucial role in hepatocarcinogenesis.

Effective eradication of established murine tumors with IL-12 gene therapy using a polycistronic retroviral vector

Our recent studies using IL-12 protein or fibroblasts genetically engineered to secrete IL-12 have demonstrated profound antitumor effects of IL-12 in murine models. The antitumor effects of local, high level IL-12 expression were examined using a retroviral vector, which can express both IL-12 subunits (p35 and p40) and the neomycin phosphotransferase (Neo)-marker gene from a polycistronic message utilizing internal ribosome entry site sequences. All animals intradermally (i.d.) receiving MCA207 murine sarcoma cell line nontransfected or Neo-transfected had progressively growing tumor, whereas all animals injected with MCA207 transfected with IL-12 were tumor free and were subsequently determined to be immune to a rechallenge of nontransfected MCA207 i.d. Similar results were obtained in experiments using the poorly immunogenic MCA102 murine sarcoma cell line. The inoculation of live MCA207-IL-12 tumor cells also caused the regression of contralateral nontransfected MCA207 inoculated either at the same time (80% protection) or up to 3 days before (33% protection) to the therapeutic tumor inoculation. In vivo depletion studies suggest that NK cells and IFN-gamma play important roles in the development of the early phase of the antitumor response, but that T cells (both CD4+ and CD8+) play the major role in the subsequent events, leading to long-term immunity. The potent antitumor effects observed for paracrine gene-delivered administration of IL-12 have thus been confirmed for multiple tumor cell types and in multiple murine strains. We believe that these results support the feasibility of IL-12 gene therapy for the treatment of human cancer.

Effective eradication of established murine tumors with IL-12 gene therapy using a polycistronic retroviral vector

Our recent studies using IL-12 protein or fibroblasts genetically engineered to secrete IL-12 have demonstrated profound antitumor effects of IL-12 in murine models. The antitumor effects of local, high level IL-12 expression were examined using a retroviral vector, which can express both IL-12 subunits (p35 and p40) and the neomycin phosphotransferase (Neo)-marker gene from a polycistronic message utilizing internal ribosome entry site sequences. All animals intradermally (i.d.) receiving MCA207 murine sarcoma cell line nontransfected or Neo-transfected had progressively growing tumor, whereas all animals injected with MCA207 transfected with IL-12 were tumor free and were subsequently determined to be immune to a rechallenge of nontransfected MCA207 i.d. Similar results were obtained in experiments using the poorly immunogenic MCA102 murine sarcoma cell line. The inoculation of live MCA207-IL-12 tumor cells also caused the regression of contralateral nontransfected MCA207 inoculated either at the same time (80% protection) or up to 3 days before (33% protection) to the therapeutic tumor inoculation. In vivo depletion studies suggest that NK cells and IFN-gamma play important roles in the development of the early phase of the antitumor response, but that T cells (both CD4+ and CD8+) play the major role in the subsequent events, leading to long-term immunity. The potent antitumor effects observed for paracrine gene-delivered administration of IL-12 have thus been confirmed for multiple tumor cell types and in multiple murine strains. We believe that these results support the feasibility of IL-12 gene therapy for the treatment of human cancer.

[Expression of sdi1, a potent inhibitor of cdk2 kinase, cdk2 and G1 cyclins and mutation of sdi1 in human gastric carcinomas]

Sdi1, also known as Cip1/Waf1, is a potent inhibitor of G1 cyclin-dependent kinases, which is induced by wild type p53 but not by mutant p53. Expression of mRNAs for sdil, cdk2 and G1 cyclins was examined in gastric carcinomas. All the cell lines expressing very low or undetectable level of sdil mRNA contains p53 gene abnormalities, while the cell lines expressing high level of sdil shares wild type p53 gene. An exception was a cell line MKN-28 with mutated p53 gene which expressed mRNAs for sdi1, cdk2 and G1 cyclins at high levels, p21 point mutation was detected in one (MKN-28) of the eight cell lines. These result suggest that low level of sdil and subsequent overexpression of cdk2 and G1 cyclins might be involved in deregulated growth of gastric carcinomas. It is likely that gene alteration of sdil and subsequent loss of function may have implication for cdk2 and G1 cyclins expression.

Frequent loss of chromosome arm 1p DNA in parathyroid adenomas

Two molecular defects have been described in parathyroid adenomas: rearrangement and overexpression of the PRAD1/cyclin D1 oncogene and allelic loss of chromosome 11 DNA, often including the multiple endocrine neoplasia type 1 (MEN1) putative tumor suppressor gene region. In an effort to identify additional parathyroid tumor suppressor genes, we examined 25 parathyroid adenomas for tumor-specific allelic loss of polymorphic DNA loci located near known or candidate tumor suppressor genes. Control leukocyte DNA from all 25 patients was heterozygous for 1 or more of the 9 chromosome 1 markers examined. Allelic loss at 1 or more of these informative loci on chromosome 1 was observed in 10 of 25 (40%) adenomas. Although many tumors lost extensive regions on chromosome 1, all but one of these tumors had allelic loss of distal 1p (1p32-pter); four tumors also lost loci on 1q. Allelic loss at 11q13, the site of the MEN1 gene, was detected in 5 of 21 (24%) informative cases, including 3 with 1p loss. In contrast, allelic loss was rarely observed at loci on 9q and 10p and was not observed at loci on 3p, 3q, 4p, 5q, 12q, 14q, 18q, 22q, or Xp. In summary, clonal allelic loss of loci on chromosome arm 1p is a frequent feature of parathyroid adenomas, implying that inactivation of a tumor suppressor gene(s) on 1p commonly contributes to their pathogenesis.

Multiple vectors effectively achieve gene transfer in a murine cardiac transplantation model. Immunosuppression with TGF-beta 1 or vIL-10

The application of gene transfer techniques to organ transplantation offers the potential for modulation of immunity directly within an allograft without systemic side effects. Expression vectors and promoter elements are important determinants of gene transfer and expression. In this study, various vectors (naked plasmid DNA, retroviral vector, herpes simplex viral vector, and adenoviral vector) with various promoters (RSV-LTR, SV40, MuLV-LTR, HCMVie1) were directly compared to demonstrate the successful gene transfer and expression of beta-galactosidase in murine myoblasts in vitro and within murine heterotopic, nonvascularized cardiac isografts or allografts in vivo. Expression of transferred genes was not toxic to cells and strength of expression varied according to the type of vector. Plasmid DNA was expressed in myocytes, retroviral vector was expressed in the graft infiltrating cells, and herpes simplex and adenoviral vectors were expressed in both myocytes and graft-infiltrating cells. Preliminary studies evaluated the ability of these vectors to deliver immunologically important signals. Allografts injected with pSVTGF-beta 1, a plasmid-encoding transforming growth factor beta 1 (TGF-beta 1) under the control of the SV40 promoter, showed significant prolongation of graft survival of 26.3 +/- 2.5 days compared with 12.6 +/- 1.1 days for untreated allografts, and 12.5 +/- 1.5 days for the allografts injected with control plasmid (P < 0.05). Allografts injected with MFG-vIL-10, a retroviral vector encoding viral interleukin-10 under the control of the MuLV-LTR, showed prolongation of graft survival of 36.7 +/- 1.3 days versus 12.6 +/- 1.1 days for the untreated allograft, and 13.5 +/- 2.0 days for the allografts injected with control retroviral vector (P < 0.001). Both vectors were transcriptionally active in vivo and did not appear to have toxic effects. Gene therapy for transplantation can induce transient expression of immunologically relevant molecules within allografts that impede immune activation while avoiding the systemic toxicity of conventional immunosuppression.

Increase in expression level of p21sdi1/cip1/waf1 with increasing division age in both normal and SV40-transformed human fibroblasts

p21sdi1/cip1/waf1 gene, whose product inhibits Cyclin/Cdk kinase and blocks cell proliferation, is known to be up-regulated by p53 and to be expressed at high levels in senescent human fibroblasts. The present paper reports that p21 expression level was much lower in SV40tsT-antigen transformed cells than in normal cells and that after inactivation of tsT-antigen it recovered to that of normal cells. However, cell division age-dependent increase in expression level of p21 occurred not only in normal human fibroblasts but also in SV40tsT-antigen transformed fibroblasts with active T-antigen. These results suggest that cell age-dependent increase in p21 occurs independently upon the function of T-antigen binding proteins including p53, while the basal expression level of p21 is up-regulated by p53 as previously reported.

Antitumor effects of interleukin-12 (IL-12): applications for the immunotherapy and gene therapy of cancer

Interleukin-12 (IL-12) is a pleiotropic cytokine, formerly termed cytotoxic lymphocyte maturation factor (CLMF) or natural killer cell stimulatory factor (NKSF), which is produced primarily by stimulated macrophages. IL-12 is a disulfide-linked heterodimeric cytokine composed of a 35-kDa light chain (p35) and a 40-kDa heavy chain (p40). Unlike most other cytokines, simultaneous transfection of mammalian cells with two different genes is necessary for the production of biologically active IL-12. IL-12 exerts a variety of biological effects on human T and natural killer (NK) cells in vitro, in addition to its ability to promote cytolytic activity, including direct stimulation of the production of IFN-gamma and other cytokines from peripheral blood T and NK cells. The recent finding that IL-12 directs the development of a TH1 type immune response from naive T cells demonstrates the critical role of IL-12 in regulating the immune response. The characteristics of IL-12 function described above strongly suggest its potential usefulness in cancer therapy. Indeed, our studies demonstrate that IL-12 exerts potent antitumor effects following systemic or local administration. We have shown that IL-12 delivered by retroviral vectors allows high-level expression and effective eradication of established tumor in multiple murine tumor models including MCA207 sarcoma. Successful therapy is associated with acquisition of a state of long-term, specific and protective immunity to subsequent challenge with tumor. We have recently received approval from the Recombinant DNA Advisory Committee to proceed with IL-12 gene therapy in humans.

Administration of systemic or local interleukin-2 enhances the anti-tumor effects of interleukin-12 gene therapy

Interleukin-12 (IL-12) is a cytokine with a wide variety of immunoregulatory activities. These include stimulation of interferon-gamma production, cytolytic activity of natural killer (NK) cells and T-cell subsets, the development of cellular immunity, and induction of maturation of Th1 cells. IL-12 also has potent anti-tumor activity in vivo. In the present study the possibility of enhanced anti-tumor activity was examined using a combination of local IL-12 by cytokine gene therapy at the tumor site, combined with systemic or local IL-2 delivery. NIH 3T3 fibroblasts transfected with the genes for both subunits of IL-12, p35 and p40, were used as the source of IL-12 therapy producing 240 HLRU/10(6) cells/48 hr. In the first part of the study the effect of different regimens of systemic IL-2 delivery with local IL-12 administration on the size and growth rate of subcutaneous MCA-105 murine sarcoma was examined. Local IL-12 alone reduced the sizes of tumors after 32 days from 163 to 26.8 mm2 (P < 0.002). Adding the longer-acting polyethylene-glycol-modified IL-2 (PEG IL-2; 30,000 IU) for 5 days prevented the development of tumors in all treated mice compared to 1/3 mice treated with PEG IL-2 alone and 3/6 mice with IL-12, but this was a highly toxic therapy and most of the animals died. Administration of 60,000 IU of IL-2 on Days 1-5 postinoculation of tumor, delivered with IL-12 gene therapy, reduced the tumor growth rate compared to animals treated with IL-2 alone (P < 0.02) or IL-12 (0.1).(ABSTRACT TRUNCATED AT 250 WORDS)

Construction and characterization of retroviral vectors expressing biologically active human interleukin-12

Interleukin-12 (IL-12) is a heterodimeric cytokine originally defined by its ability to induce the maturation of cytolytic lymphocytes and by its capacity to effectively synergize with IL-2 in the induction of cytolytic activity. Recent studies in mice have demonstrated the ability of IL-12 to cause tumor regression and stimulate long-term antitumor immunity in treated animals. To examine the antitumor effect of direct gene transfer of IL-12 into tumors, we have developed retroviral vectors that coordinately express both subunits of IL-12. An MFG-based retroviral vector was used to generate a recombinant retrovirus in which a long terminal repeat (LTR)-driven polycistronic transcript encodes both subunits of human IL-12: hp35 and hp40 cDNAs are linked and coexpressed using the internal ribosome entry site (IRES) from the encephalomyocarditis virus (DFG-hIL-12). In addition, two IRES sequences were used to express both subunits of IL-12 and a neomycin resistance (neoR) selectable marker gene from the same polycistronic message (TFG-hIL-12). The amphotropic DFG-hIL-12 and TFG-hIL-12 viruses were used to infect both human and murine cell lines as well as primary tumor cultures. The production of human IL-12 by the nonselected, infected cells was measured in both a PHA blast proliferation bioassay and an ELISA and ranged from 15 to 40 ng/10(6) cells per 24 hr. Following G418 selection of TFG-hIL-12-infected cells, the level of expression of IL-12 was significantly higher (up to 120 ng/10(6) cells per 24 hr). The IL-12 protein secreted by the infected cells exhibited all of the biologic activities of recombinant hIL-12: proliferation of activated natural killer (NK) and T cells, stimulation of interferon-gamma (IFN-gamma) induction by NK and T cells, and enhancement of lymphokine-activated killer (LAK) activity. These retroviral vectors expressing human IL-12 should be useful in evaluating the biological properties of IL-12 as well as for use in clinical trials for gene therapy of patients with cancer.

Disorder in ultrastructure of basement membrane and mechanical junction in human esophageal cancer

The ultrastructure and clinical significance of the basement membrane (BM) are still unclear in esophageal cancer. In this report, we examined the ultrastructure of the BM and microstructures related intercellular adhesion in squamous cell carcinoma of human esophagus using a transmission electron microscope, and investigated their clinical significance. BM was absent in 38% of the examined cases and the frequency or the presence of the microstructures of cancer cells of the infiltrating margin (CCIM) was negatively related to the presence of BM (BM-P); CCIM of BM-P tumors often had smaller number per cell of desmosomes and cytoplasmic processes. These results indicate that CCIM of BM-P tumor are in an 'inconvenient status' for tumor cells to form a firm group. In the intercellular space between CCIM and BM or surrounding stromal cells, all of the CCIM of BM-P tumors had hemidesmosomes, but not those of BM absent (BM-A) tumors. Though no statistical significant difference was found in our clinical observation between BM-P and BM-A tumors, the present study suggested that a considerable proportion of cancer cells have abnormal intercellular adhesiveness via a mechanical mechanism related to the presence or absence of BM.

Recombinant IL-12 administration induces tumor regression in association with IFN-gamma production

Recent evidence supports the critical and proximate role of IL-12 in regulating both T and NK cell function during inflammation. In these studies, we evaluated the in vivo antitumor activity of murine IL-12 in murine adenocarcinoma and sarcoma models using both systemic and peritumoral administration. Antitumor effects were consistently demonstrated both in models of microdisease, in which IL-12 treatment was initiated soon after tumor inoculation (1 to 5 days), and in animals bearing large established tumors (7 to 14 days). Treatment with IL-12 markedly prolonged survival and, in most cases, caused complete tumor regression. Significant reduction in pulmonary metastases after systemic treatment was observed when treatment was delayed for 10 days after tumor inoculation. Increases in serum IFN-gamma, TNF-alpha, and nitrogen oxides were demonstrated, exceeding those observed with IL-2 treatment. Systemic administration of anti-IFN-gamma Abs before IL-12 treatment nearly completely abrogated the antitumor effect in experiments using subcutaneous tumors or pulmonary metastases. Depletion of the individual T cell subsets CD4 and CD8 by systemic administration of mAbs diminished the effectiveness of IL-12 when administered in combination. An infiltrate composed primarily of CD8+ + cells was demonstrated by using immunohistochemical analysis of tumors after IL-12 treatment. Minimal apparent toxicity was demonstrated at effective doses (0.1 to 1.0 microgram/day) of IL-12. These results indicate that IL-12 is an effective and minimally toxic antitumor agent in murine tumor models and leads to an immune-mediated rejection involving, at least in part, IFN-gamma, CD4+, and CD8+ cells. Human clinical trials of IL-12 for the treatment of malignancy are supported by these studies.

Recombinant IL-12 administration induces tumor regression in association with IFN-gamma production

Recent evidence supports the critical and proximate role of IL-12 in regulating both T and NK cell function during inflammation. In these studies, we evaluated the in vivo antitumor activity of murine IL-12 in murine adenocarcinoma and sarcoma models using both systemic and peritumoral administration. Antitumor effects were consistently demonstrated both in models of microdisease, in which IL-12 treatment was initiated soon after tumor inoculation (1 to 5 days), and in animals bearing large established tumors (7 to 14 days). Treatment with IL-12 markedly prolonged survival and, in most cases, caused complete tumor regression. Significant reduction in pulmonary metastases after systemic treatment was observed when treatment was delayed for 10 days after tumor inoculation. Increases in serum IFN-gamma, TNF-alpha, and nitrogen oxides were demonstrated, exceeding those observed with IL-2 treatment. Systemic administration of anti-IFN-gamma Abs before IL-12 treatment nearly completely abrogated the antitumor effect in experiments using subcutaneous tumors or pulmonary metastases. Depletion of the individual T cell subsets CD4 and CD8 by systemic administration of mAbs diminished the effectiveness of IL-12 when administered in combination. An infiltrate composed primarily of CD8+ + cells was demonstrated by using immunohistochemical analysis of tumors after IL-12 treatment. Minimal apparent toxicity was demonstrated at effective doses (0.1 to 1.0 microgram/day) of IL-12. These results indicate that IL-12 is an effective and minimally toxic antitumor agent in murine tumor models and leads to an immune-mediated rejection involving, at least in part, IFN-gamma, CD4+, and CD8+ cells. Human clinical trials of IL-12 for the treatment of malignancy are supported by these studies.

[Phimosis as a pathogenetic factor in urinary tract infection and vesicoureteral reflux]

The present study has been carried out to clarify relationship between phimosis and urinary tract infection or vesicoureteral reflux. The subjects consisted of 654 boys up to 15 years old with phimosis who had been treated at the outpatient division, Fukuoka University Hospital during 13 years from 1974; 393 boys (60%) with false phimosis, 261 boys (40%) with true phimosis. Thirty three cases (5%) had abnormal voiding (weak stream, preputial ballooning, dribbling etc.) Boys with true phimosis without abnormal voiding showed high incidence of urinary tract infection compared with normal subject, and if these boys had abnormal voiding symptoms as well, the incidence of urinary tract infection, particularly in the form of pyelonephritis, was noted to be high. Therefore, we suggest that boys with phimosis should be treated surgically. The incidence of urinary tract infection in boys with false phimosis were similar to normal group. All cases except one of vesicoureteral reflux accompanied by true phimosis was diagnosed as primary reflux cystoscopically. Therefore in most cases of phimosis associated with reflux, phimosis is determined to be only an accessory factor of vesicoureteral reflux. And refluxing patients should be worked up for urinary tract infection after they have had circumcision. Only in one boy with phimosis and reflux, was the reflux thought to be secondary reflux caused by phimotic obstruction.

Preparation of a subtractive cDNA library enriched in cDNAs which expressed at a high level in cultured senescent human fibroblasts

Subtracted cDNA library was prepared by subtracting [cDNA from young growing SV40-transformed human fibroblasts] from [cDNA from growing SV40-transformed fibroblasts in extended lifespan]. Isolated cDNA clones which expressed at high level in life-extended transformed cells also expressed at high level in normal senescent fibroblasts but did at low level in growing and growth-arrested young cells. Neither fibronectin nor procollagen cDNA was isolated. This cDNA library is useful for isolation of senescent-specific cDNA species which express at high level in normal senescent cells but at low level in growing and growth-arrested young cells, avoiding growth-arrest-specific cDNAs.

Coronary collateral circulation and diastolic function

Patients with coronary artery disease reportedly have an impaired left ventricular filling. To evaluate the effects of coronary collaterals on diastolic function in patients with effort-induced angina, resting radionuclide ventriculography was performed in 14 patients with severe isolated (> or = 90% diameter) stenosis of the left anterior descending coronary artery and in seven normal subjects. Contrast ventriculography showed normal wall motion in all patients. Functional indices obtained by radionuclide ventriculography were compared between those patients with collateral vessels, Rentrop classification grades 1 (n = 7) and 3 (n = 1), and those patients without (n = 6) collateral vessels. Global peak filling rate was significantly (P < 0.01) reduced in the patients with collaterals. The septal, apical and lateral peak filling rates were also reduced in patients with collateral vessels, with the reduction in lateral peak filling rate being statistically significant (P < 0.05). The indices of systolic function and the temporal diastolic asynchronous index were similar, irrespective of the presence of collaterals. The exercise tolerance as evaluated by the rate-pressure product at peak treadmill exercise stress testing in 12 patients was significantly (P < 0.01) lower in those with collateral vessels. Angiographically visible collaterals could be a marker for more severe coronary stenosis in patients with effort-induced angina, and an indicator of the severity of deterioration in left ventricular diastolic function.

Heparin suppresses endothelin-1 peptide and mRNA expression in cultured endothelial cells of spontaneously hypertensive rats

Heparin given sc consistently lowers blood pressure in spontaneously hypertensive rats (SHR). This study was designed to examine heparin's effect on vasoconstrictor endothelin-1 production in cultured aortic endothelial cells (EC). Aortic EC from SHR and normotensive Wistar Kyoto rats (WKY) were cultured and incubated with or without different concentrations of heparin. Heparin suppressed endothelin-1 release and endothelin-1 mRNA expression in a dose- and a time-dependent fashion in both WKY and SHR. The suppressive effects were more augmented in SHR than in WKY: SHR versus WKY--endothelin-1 level at 6 h = 8 +/- 1.8 versus 14 +/- 2.2 pg/10(6) cells (P < 0.01) and mRNA expression--85 versus 52% maximal inhibition by heparin, 10 U/mL (=70 micrograms/mL) (P < 0.01). When heparin was added with transcriptional inhibitor actinomycin D and incubated for 30 min, no further inhibition of endothelin-1 mRNA level measured after another 30 minutes was observed compared with the endothelin-1 mRNA level in cultured EC of SHR treated with just actinomycin D at 30 min. These results suggest that heparin regulates endogenous endothelin-1 production by cultured EC, probably at the transcriptional level, and that this effect is more marked in SHR than in WKY.