Mouse Mef2b gene: unique member of MEF2 gene family

The myocyte enhancer factor 2 (MEF2) gene family, which belongs to the MADS [MCM1, agamous, deficiens, serum response factor (SRF)] superfamily, is thought to play an important role in differentiation of myocytes, including cardiomyocytes. To better understand the mouse Mef2 gene family, the mouse Mef2b gene, which was found to be expressed in undifferentiated embryonal cells, was characterized. The Mef2b gene was found to be more than 30 kb in length, consisting of 11 exons. Eight exons correspond to coding regions and the remaining 3 exons for the 5' part are alternatively used. Two internal exons are subject to alternative splicing, resulting in production of four subtypes of mouse MEF2B peptides. Fluorescence in situ hybridization (FISH) and inter-specific backcross analysis identified the Mef2b gene locus. Mef2b gene was expressed in heart or skeletal muscle of early mouse embryo, but not in those of adult mouse. Functionally, mouse MEF2B did not exhibit DNA binding with the MEF2 consensus element in vitro, but did cause transcriptional activation of the MEF2 element, although it was less effective than human MEF2B. Based on these results, mouse MEF2B seems to have a unique character, distinct from other MEF2 family members.

A new prognostic strategy for gastric carcinoma: mRNA expression of tumor growth-related factors in endoscopic biopsy specimens

OBJECTIVE

The study analyzed the prognostic value of the transcription of several tumor growth-related genes in gastric carcinoma biopsy specimens.

SUMMARY BACKGROUND DATA

The nodal status is one of the most significant prognostic factors in gastric carcinoma. There are, however, no satisfactory parameters for the preoperative assessment of nodal status.

METHODS

A reverse transcriptase-polymerase chain reaction analysis was used to analyze the transcription of several tumor growth-related genes in endoscopic biopsy specimens from 78 gastric carcinomas. The factors examined were cyclin D1, cyclin E, urokinase-type plasminogen activator, 72-kd type IV collagenase, vascular endothelial growth factor, platelet-derived growth factor-A (PDGF-A), transforming growth factor-beta, and interleukin-10. The relation between the mRNA expression and the clinical pathologic parameters was analyzed statistically.

RESULTS

The incidence of PDGF-A (p = 0.010) and transforming growth factor-beta (p = 0.009) mRNA expression increased as the pathologic stage advanced. Nodal metastasis correlated with cyclin D1 (p = 0.045), cyclin E (p = 0.037), urokinase-type plasminogen activator (p = 0.047), and PDGF-A (p = 0.003) mRNA. Interestingly, the expression of PDGF-A mRNA showed a positive correlation (p = 0.004) with the early presence of lymph node metastases.

CONCLUSIONS

Tumor growth-related factor mRNA in biopsy specimens may be a new prognostic tool.

Cloning and characterization of NE-dlg: a novel human homolog of the Drosophila discs large (dlg) tumor suppressor protein interacts with the APC protein

We have cloned a cDNA for a novel human homolog of the Drosophila discs large (dig) tumor suppressor protein, termed NE-dlg (neuronal and endocrine dig). Northern blot analysis revealed that the gene is highly expressed in neuronal and endocrine tissues. Fluorescence in situ hybridization (FISH) and radiation hybrid mapping studies localized the NE-dlg gene to chromosome Xq13. We also found that the NE-dlg gene encoded a 100 kDa protein. Immunolocalization studies using an NE-dlg antibody showed that the protein tended to be expressed in non-proliferating cells, such as neurons, cells in Langerhans islets of the pancreas, myocytes of the heart muscles, and the prickle and functional layer cells of the esophageal epithelium. Proliferative cells, including various cultured cancer cell lines and basal cells in the esophageal epithelium, showed little expression of the NE-dlg protein. In addition, yeast two-hybrid screening and in vitro binding assays revealed that the NE-dlg interacted with the carboxyl-terminal region of the APC tumor suppressor protein. These data suggest that NE-dlg negatively regulates cell proliferation through its interaction with the APC protein.

Cloning and expression of cDNA encoding heart-type isoform of AMP deaminase

Mouse cDNA for the heart-type (H) isoform of AMP deaminase (EC 3.5.4.6., AMPD) has been isolated and characterized. The cDNA for the Ampd gene expressed in heart is predicted to encode a peptide of 766 amino acids with a molecular mass of 88 kDa. The coding region of this cDNA was quite homologous to the human AMPD3 gene which encodes the erythrocyte-type (E) isoform of AMPD, although the H-isoform of rodent AMPD was reported to be immunologically distinct from the E-isoform of human AMPD. The non-coding region of the isolated cDNA is not homologous to human AMPD3, while rodent Ampd1 has similarity to human AMPD1 in the non-coding region as well as in the coding region. The transcripts for the cloned cDNA were expressed in heart, slow-twitch skeletal muscle and non-muscle tissues. Prokaryotic expression showed that this cDNA encodes a catalytically active enzyme which reacts to the specific antibody raised to the H-isoform of AMPD.

Melanoma antigen-encoding gene-1 expression in invasive gastric carcinoma: correlation with stage of disease

BACKGROUND

A human melanoma antigen-encoding gene-1, MAGE-1 gene, may be linked to the neoplastic transformation. In the present study, we extended this association with human gastric carcinomas. Specifically, we focused on the relationship between MAGE-1 gene expression and the histologic stage of gastric carcinoma.

METHODS

We used a reverse transcription-polymerase chain reaction assay (RT-PCR) to analyze the expression of the MAGE-1 gene in 38 endoscopic biopsy specimens from gastric carcinomas. We also studied the relationship between the expression of MAGE-1 gene and the genetic expression of several tumor invasion-related factors, including 72 kD type IV collagenase (MMP2), urokinase-type plasminogen activator (uPA), platelet-derived growth factor A (PDGF-A), and vascular endothelial growth factor (VEGF).

RESULTS

Eleven of the 38 tumor samples (28.9%) expressed the MAGE-1 gene. MAGE-1 gene expression was present only in two of the 38 adjacent nontumor samples (5.3%). MAGE-1 gene expression in the 38 tumor samples was significantly correlated with the histological stage of disease (P = 0.0008), especially with the depth of histologically confirmed tumor invasion (t1 vs. t2 or greater, P = 0.00048). The expression of MAGE-1 gene correlated with the expression of MMP2 (P = 0.0064), uPA (P = 0.0390), and PDGF-A (P = 0.00018).

CONCLUSIONS

These data suggest that the MAGE-1 gene may be activated in gastric carcinomas during periods of their development or invasion. In addition, a relationship between MAGE-1 gene expression and expression of invasion-related factors has been demonstrated.

Immunosuppressive cytokines (IL-10, TGF-beta) genes expression in human gastric carcinoma tissues

BACKGROUND

Contribution of immunosuppressive cytokines to tumor progression in many types of cancers has been suggested. To characterize the in vivo expression of immunosuppressive cytokines in gastric cancer, we analyzed the messenger RNA (mRNA) expression of transforming growth factor-beta (TGF-beta) and interleukin-10 (IL-10) in human gastric carcinoma tissues.

METHODS

Both tumor tissues and nontumor tissues from each resected specimen of 29 primary gastric carcinomas were tested for IL-10 and TGF-beta mRNA expression by the reverse transcriptase-polymerase chain reaction (RT-PCR), and the mRNA expression was correlated with various pathological parameters of the tumors.

RESULTS

Among the 29 tumors, mRNAs of TGF-beta and IL-10 were detected in 79% and 62% of tumor samples, respectively. These cytokines were detected only in 31% for TGF-beta and 17% for IL-10 in nontumor samples. Both mRNAs were frequently expressed in the poorly differentiated adenocarcinomas and the tumor tissues with high degree of stage or lymph node metastasis.

CONCLUSIONS

Local expression of immunosuppressive cytokines may contribute to the progression of primary gastric carcinomas possibly through immunosuppression.

Immunosuppressive cytokines (IL-10, TGF-beta) genes expression in human gastric carcinoma tissues

BACKGROUND

Contribution of immunosuppressive cytokines to tumor progression in many types of cancers has been suggested. To characterize the in vivo expression of immunosuppressive cytokines in gastric cancer, we analyzed the messenger RNA (mRNA) expression of transforming growth factor-beta (TGF-beta) and interleukin-10 (IL-10) in human gastric carcinoma tissues.

METHODS

Both tumor tissues and nontumor tissues from each resected specimen of 29 primary gastric carcinomas were tested for IL-10 and TGF-beta mRNA expression by the reverse transcriptase-polymerase chain reaction (RT-PCR), and the mRNA expression was correlated with various pathological parameters of the tumors.

RESULTS

Among the 29 tumors, mRNAs of TGF-beta and IL-10 were detected in 79% and 62% of tumor samples, respectively. These cytokines were detected only in 31% for TGF-beta and 17% for IL-10 in nontumor samples. Both mRNAs were frequently expressed in the poorly differentiated adenocarcinomas and the tumor tissues with high degree of stage or lymph node metastasis.

CONCLUSIONS

Local expression of immunosuppressive cytokines may contribute to the progression of primary gastric carcinomas possibly through immunosuppression.

Role of nitric oxide derived from alveolar macrophages in the early phase of acute pancreatitis

BACKGROUND

Acute pancreatitis is known to be often complicated by lung injury; however, the pathogenesis of lung injury in the early phase of acute pancreatitis remains unclear. Alveolar macrophages (AMs) have been suggested to contribute to lung injury by releasing various cytotoxic products including nitric oxide (NO). We investigated the role of AM-derived NO in the pathogenesis of lung injury during the early phase of acute pancreatitis.

MATERIALS AND METHODS

Pancreatitis was induced in rats by selective pancreatic duct ligation (SPL). The mRNA expression of inducible NO synthase (iNOS) in AMs from rats after SPL (at 1, 2, 4, 6, 8, 12, 18, and 24 hr) was examined by reverse-transcriptase polymerase chain reaction method. The in vitro production of NO and superoxide by AMs 24 hr after SPL was measured and the cytotoxic effect of AMs on human umbilical vein endothelial cells (HUVECs) was examined with or without the NO synthase inhibitor L-NG-monomethyl-L-arginine (L-NMMA). The in vivo effect of L-NMMA on lung injury was also examined.

RESULTS

In this model, serum amylase level peaked 24 hr after SPL, whereas PaO2 bottomed 24 hr after SPL. (In vitro) AMs expressed iNOS mRNA 6 hr after SPL and generated large amounts of NO and superoxide and demonstrated strong cytotoxicity against HUVECs significantly. This cytotoxicity was reduced by the administration of L-NMMA. (In vivo) L-NMMA administrated to rats with pancreatitis apparently reduced lung edema histologically and improved the PaO2.

CONCLUSION

Our results suggest that, during early phase of acute pancreatitis, AM-derived NO contributes to lung injury. Administration of the NOS inhibitor L-NMMA prevented lung injury in this model.

Subunit composition of AMPD varies in response to changes in AMPD1 and AMPD3 gene expression in skeletal muscle

Adenosine monophosphate deaminase (AMPD), a central enzyme in energy metabolism in skeletal muscle, is encoded by a multigene family in higher eukaryotes. Denervation was used as a stimulus to induce a change in fiber type composition of rat gastrocnemius muscle and, consequently, gene expression. Specific antisera and nucleic acid probes were used to assess changes in expression of the AMPD1 and AMPD3 genes. Total AMPD activity in denervated skeletal muscle increased by 34%. The composition of the AMPD tetrameric holoenzyme was altered in two ways: The percentage of AMPD holoenzyme molecules consisting of one or more AMPD3 subunits increased three-fold, and the percentage of AMPD1 mRNA that excludes exon 2-encoded sequences doubled. These results suggest that expression of the AMPD1 and AMPD3 genes may be coordinated in myocytes to effect production of an AMPD holoenzyme of varying subunit composition.

Induction of inflammatory cytokines in effusion cavity by OK-432 injection therapy for patients with malignant effusion: role of interferon-gamma in enhancement of surface expression of ICAM-1 on tumor cells in vivo

The intracavitary injection of OK-432, a streptococcal preparation, has been shown to be an effective immunotherapy for patients with malignant effusion. We found that this therapy increases surface expression of intercellular adhesion molecule-1 (ICAM-1) on tumor cells, and that the degree of increased ICAM-1 was correlated with therapeutic effects. In the present study, we investigated the ability of OK-432-induced inflammatory cytokines, such as interferon-gamma (IFN-gamma), tumor necrosis factor-alpha (TNF-alpha), and interleukin-1 beta (IL-1 beta), to enhance ICAM-1 expression. We treated 17 patients who had a malignant effusion with OK-432. At 24 hr after OK-432 injection, ICAM-1 levels on tumor cells were increased significantly in responders except in one case (n=9), whereas no change was evident in nonresponders except in two cases (n=8). Induced maximum levels of IFN-gamma in responders were significantly higher than those in nonresponders. In contrast, there was no significant difference in the induced TNF-alpha or IL-1 beta levels between the two groups. Two types of cultured tumor cells derived from responder patients were successfully established from the 17 different tumor cells in effusion. We performed an in vitro study using these cultured tumor cells. Treatment of the two cultured tumor cells with recombinant IFN-gamma, but not recombinant TNF-alpha or IL-1 beta, significantly increased their ICAM-1 expression to a clinically detectable level. Direct treatment of the tumor cells with cell-free effusion samples obtained from the same patients 24 hr after the therapy successfully increased ICAM-1 expression and this action was blocked completely only by a pretreatment with anti-IFN-gamma mAb. Our results suggests that in this therapy IFN-gamma plays a crucial role in enhancing ICAM-1 expression by tumor cells and that induced IFN-gamma levels may be a useful marker for evaluation of the therapeutic effect.

Vascular endothelial growth factor and platelet-derived growth factor are potential angiogenic and metastatic factors in human breast cancer

BACKGROUND

Angiogenesis is a prerequisite for tumor growth and metastasis. Tumor angiogenesis may be mediated by several angiogenic factors such as vascular endothelial growth factor (VEGF), platelet-derived growth factor (PDGF), transforming growth factor-alpha, and basic fibroblast growth factor.

METHODS

Differential mRNA expressions of VEGF, PDGF (A chain), transforming growth factor-alpha and basic fibroblast growth factor in 32 primary invasive breast tumors were examined by reverse transcriptase-polymerase chain reaction. We analyzed relationships between mRNA expressions of these angiogenic factors and the degree of angiogenesis, tumor size, and metastasis. Quantification of angiogenesis was achieved by the immunohistochemical staining of endothelial cells with antibody to CD31.

RESULTS

VEGF and PDGF-A mRNAs were expressed more frequently in breast tumors than in nontumor breast tissues, whereas no difference was found in expression frequency of either transforming growth factor-alpha or basic fibroblast growth factor mRNA. Vascular counts in tumors correlated with each expression frequency of VEGF and PDGF-A mRNA. PDGF-A mRNA was expressed more frequently in tumors with lymph node metastasis than in those without metastasis.

CONCLUSIONS

Expression of VEGF and PDGF mRNAs detected by reverse transcriptase-polymerase chain reaction in breast tumors correlates with tumor-related characteristics of angiogenesis and metastatic potential. Analysis of these mRNAs by reverse transcriptase-polymerase chain reaction may be useful for assessing the biologic behavior of a breast tumor before surgical treatment.

A possible role of TGF-beta in the formation of malignant effusions

The detailed mechanisms underlying the formation of malignant effusions are incompletely defined. In order to determine whether transforming growth factor-beta (TGF-beta) would contribute to the formation of malignant effusions, we investigated the effect of TGF-beta on the morphology, growth, and permeability of human mesothelial cells, which are thought to serve as a permeability barrier in the pleuroperitoneal cavities. Treatment of the mesothelial cells with a TGF-beta dose ranging from 0.1 to 10 ng/ml for 96 hr induced distinct morphologic changes in the cells. Each cell increased in size as did the volume of the intercellular spaces. TGF-beta also significantly inhibited the growth of mesothelial cells at a concentration ranging from 0.1 to 10 ng/ml. This growth inhibition was blocked completely by the addition of anti-TGF-beta antibody. Treatment of the mesothelial cells with 2.0 ng/ml TGF-beta significantly increased the permeability of a mesothelial cell monolayer as assessed by a FITC-albumin permeability assay. In our clinical analysis using 10 effusion samples obtained from patients with various types of carcinoma cells, considerable level of TGF-beta could be detected by ELISA, ranged from 0.90 to 8.75 ng/ml. Our data suggest that TGF-beta plays an important role in the formation of malignant effusions through structural and functional damage to the mesothelial cells. Malignant effusions may accumulate in the pleuroperitoneal cavity as a result of the mesothelial cell damage caused by this cytokine which is released from disseminated cancer cells.

The MEF2B homologue differentially expressed in mouse embryonal carcinoma cells

The MEF2 gene family encodes a MADS-box transcription factor which regulates expression of many muscle-specific genes. We examined the expression of the MEF2 genes in mouse embryonal carcinoma P19 cells before and after in vitro muscle differentiation induced by dimethyl sulfoxide (DMSO). At least three different MADS/MEF2 domains (MEF2A, 2B and 2D) were isolated from P19 cells with the MOPAC technique (mixed oligonucleotides primed amplification of cDNA). Although two of the MADS/MEF2 domain sequences were identical to those of human MEF2A and MEF2D, another domain sequence was similar but not identical to that of human MEF2B. While the transcription of MEF2A and MEF2D was up-regulated during differentiation of P19 cells, the MEF2B homologue was abundantly transcribed in undifferentiated P19, F9 and ES cells and down-regulated in adult heart, skeletal muscle or brain, suggesting that the murine MEF2B homologue might have a function distinct from other members of the MEF2 gene family in embryogenesis and development.

CEA-mediated homotypic aggregation of human colorectal carcinoma cells in a malignant effusion

This study was performed to clarify the role of carcinoembryonic antigen (CEA) in the aggregation of colorectal carcinoma (CRC) cells in malignant effusions. We analysed freshly purified CRC cells from one patient, which expressed CEA (98% positive cells) on the surface and formed huge cell aggregates in the patient's ascites. The carcinoma cells expressed Sialyl Lewis A (82%), Sialyl Lewis X (92%) and the beta 1 integrin subunit (78%) but did not express the pair-ligands for these molecules. Cell aggregation was completely inhibited by anti-CEA mAb. The decreased CEA expression induced by phosphatidylinositol-specific phospholipase C (PI-PLC) treatment led to decreased cell aggregation. We also examined the correlation between the degree of cell aggregation and CEA expression using smears of ascites fluid from 27 patients with colorectal cancer. There was a significant correlation between the degree of cell aggregation and CEA expression by CRC cells. The present study provided the first evidence that CEA molecules mediate the homotypic aggregation of CRC cells in malignant effusions.

Identification of functional domains in AMPD1 by mutational analysis

AMP deaminase (AMPD) is a complex allosteric enzyme encoded by a multigene family in higher eukaryotes. The amino terminus of each AMPD gene is unique, while the mild and carboxy termini have been highly conserved among all the AMPD genes. Mutational analyses of the AMPD1 gene demonstrate that the catalytic site and a regulatory site, likely an ATP binding site, are located in the highly conserved carboxy terminus. Deletion mutants and a normal splice variant of AMPD1 demonstrate that the amino terminus has a profound influence on catalytic activity of AMPD and by inference from prior studies this region also influences binding of AMPD1 to myosin. Results of these studies suggest a regulatory model in which alternative splicing in the amino terminal region of AMPD1 generates isoforms of AMPD that exhibit differential sensitivity to effector molecules such as ATP.

Interleukin-2 (IL-2) production by human B-cell line

A human B-cell line (Hairy-BM) constitutively secreting interleukin-2 (IL-2) was established from tumor tissue resected surgically from a patient with breast cancer. Hairy-BM was found to be 100% CD20+, 98% surface immunoglobulin (sIg) G+, 98% sIg kappa chain+, 100% HLA-DR+, 94% IL-2 receptor (IL-2R alpha), 98% IL-2R beta, and devoid of T-cell, monocyte, and natural killer cell surface antigens. The B-cell origin of Hairy-BM was also confirmed by clonally rearranged Ig heavy- and Ig light-chain genes. The growth of Hairy-BM expressing IL-2R was promoted by recombinant IL-2 (rIL-2) and anti-CD25 antibody significantly blocked the growth enhancement. IL-2 secretion from Hairy-BM was confirmed by radioimmunoassay. By using a sensitive polymerase chain reaction technique, we demonstrated that Hairy-BM expressed IL-2 mRNA, IL-2R alpha mRNA, and IL-2R beta mRNA. These findings indicate that certain B-cells not only produce, but also respond to IL-2 in an autocrine fashion with increased proliferation.

[Establishment and characterization of a new cell line (KT-COLO-8) derived from a colonic mucinous adenocarcinoma]

We have established a human colonic carcinoma cell line, designated KT-COLO-8, derived from cancerous ascites of a 64-year-old male patient who had mucinous adenocarcinoma of the transverse colon. The cells have been cultured with RPMI-1640 medium supplemented with 10% fetal bovine serum. They grew in vitro free-floating and formed sheet-like clusters as large as 2-3 mm in diameter. Population doubling time for the cells was 48 hours. The chromosome number ranged from 48 to 50. The Q-band analysis revealed abnormal karyotype with three marker chromosomes including 1p-, 4q- and 5q-. The cells produced and released high level of carcinoembryonic antigen (CEA) in the conditioned medium. Percentage of CEA positive cells was 98%. An aggregation assay revealed that 80% of the cells dissociated into single cells aggregated within 30 min. The self aggregation of the cells was completely inhibited only by anti-CEA monoclonal antibody, suggesting that the cluster formation of KT-COLO-8 cells was dependent on CEA molecules.

Increased proliferation of a human breast carcinoma cell line by recombinant interleukin-2

Two adenocarcinoma cell lines, Breast M25-SF and Breast M, were established from tumor tissue resected surgically from a patient with breast cancer. One, Breast M25-SF, expresses interleukin-2 receptor (IL-2R) on the cell surface and the other, Breast M does not. The effects of recombinant interleukin-2 (rIL-2) on the proliferation of these cell lines were investigated. The growth of Breast M25-SF was significantly promoted by rIL-2 ranging from 1.25 U/ml to 640 U/ml. Anti-CD25 (Tac) antibody significantly blocked the growth enhancement of Breast M25-SF by rIL-2. Breast M, however, did not respond to rIL-2. To confirm more directly the promotion of Breast M25-SF growth by rIL-2, cloning of IL-2 responders from parent Breast M25-SF cells was carried out by limiting dilution without feeder cells in 96-well microplates. No colony formation was found in 24 wells without rIL-2. Eleven, 13 and 6 clones were established from groups of 24 wells containing rIL-2 at 200, 20 and 2 U/ml respectively. All of the clones expressed IL-2R and respond to rIL-2. By using a sensitive polymerase chain reaction technique, we demonstrated that Breast M25-SF but not Breast M expressed IL-2 mRNA, and IL-2 secretion from Breast M25-SF but not Breast M was also confirmed by radioimmunoassay. These findings suggest a role for IL-2 in autocrine support of Breast M25-SF growth. IL-2 may play an important role in the growth control of breast carcinoma cells.

Characterization and augmentation of CD4+ cytotoxic T cell lines against melanoma

Cytotoxic T cells have been implicated in the control of the progression of human melanoma. Most studies on human tumor T cell immunity have focused on the CD3+CD8+ cytotoxic T lymphocyte (CTL) phenotype; however, CD3+CD4+ CTL are important effector cells in other diseases and may also contribute to antimelanoma immunity. In this study we compared the functional activity of CD3+CD4+ and CD3+CD8+ CTL lines generated against autologous melanoma cells. CD8+ CTL had twofold higher cytotoxicity and serine esterase activity than CD4+ CTL. CD8+ CTL also were better binders to autologous melanoma cells. Binding of both CD4+ and CD8+ CTL to melanoma cells was significantly inhibited by ICAM-1 mAb. Interleukin-2 (IL-2) and IL-4 secretion was induced in both CD4+ and CD8+ CTL after stimulation by melanoma cells. A reverse transcriptase polymerase chain reaction performed on specific messenger RNA showed that both CD4+ and CD8+ CTL expressed IL-1, IL-2 and IL-4; CD4+ CTL also expressed interferon gamma (IFN). Both CTL phenotypes expressed receptors for IL-2 and IFN but only CD4+ CTL expressed the receptor for IL-4. Methods to augment CD4+ CTL growth were assessed using different combinations of cytokines. The combination of IL-2, IL-4 and IFN provided the optimal stimulation. Treatment of melanoma target cells with IL-4 and IFN enhanced CD4+ CTL recognition activity. CD4+ T cells are associated with antigen memory response and helper function, therefore activation of CD4+ CTL may be more beneficial with respect to long-term protective antimelanoma immunity.

Interleukin 4 regulates G1 cell cycle progression in gastric carcinoma cells

We have previously reported that interleukin 4 (IL-4) inhibits the growth of human gastric carcinoma cells. To investigate the mechanism for this inhibition we analyzed the effect of IL-4 on cell cycle progression of the IL-4-sensitive gastric carcinoma cell line, HTB-135. IL-4 significantly inhibited cell cycle G1-S-phase progression. To assess the postreceptor molecular events that transduced the negative-growth signals by IL-4, we analyzed the expression of cell cycle nuclear-regulating factors such as retinoblastoma gene product (Rbp), c-myc, c-myc protein (c-mycp), and cyclin D1 expression which are known to be regulators of G1-S-phase transition. IL-4 was found to induce an unphosphorylated form of Rbp within 24 h and significantly reduce the phosphorylated form at 48 h. The transition of Rbp to a hypophosphorylated form concurs with the decrease in c-myc gene expression and c-mycp. In addition, we demonstrated that IL-4 down-regulated p34cdc2, a kinase associated with Rbp phosphorylation and cyclin D1. Cyclin D1, considered as a critical nuclear regulatory factor of G0-G1 to S-phase transition was down-regulated 24 and 48 h post-IL-4 treatment as well. These studies suggest that IL-4 inhibits gastric cell proliferation by blocking cell cycle progression by down-regulating several key G0-G1 cell cycle nuclear-regulating factors.

Immunologic assessment of host defense impairment in patients with septic multiple organ failure: relationship between complement activation and changes in neutrophil function

BACKGROUND

The pathogenesis of gram-negative sepsis-induced multiple organ failure (MOF) remains to be elucidated.

METHODS

Blood samples were obtained from eleven patients with septic MOF, three patients with sepsis, three patients who underwent operation, and three healthy volunteers. In these patients the relationship between changes in polymorphonuclear neutrophil (PMN) function and complement activation was investigated.

RESULTS

PMNs from patients with sepsis exhibited enhanced endothelial cell adhesion, enhanced chemotaxis, increased oxygen radical generation, and increased lysosomal enzyme release. Although PMNs from patients with septic MOF also exhibited enhanced adhesion and chemical mediator production, chemotaxis was markedly depressed. Complement activation in septic MOF was indicated by decreases in total complement activity and complement component 4 (C4) and increases in C3a and C4a des-Arginine. Increases in plasma concentrations of circulating immunoglobulin G immune complexes and decreases in PMN Fc gamma R expression suggest that the classic pathway is the main pathway of complement activation. On the other hand, we could not detect decreases in C4 or increases in C4a des-Arginine in patients with sepsis, suggesting that the alternate pathway is the main pathway of complement activation. Increases in serum concentrations of the membrane attack (SC5b-9) complex also suggested that activated complement itself may participate in organ injury in patients with septic MOF. Moreover, PMN up-regulation of surface inhibitory factors of complement activation likely allows these neutrophils to survive and function.

CONCLUSIONS

The combination of changes in PMN function and complement activation appears to be intimately associated with the pathogenesis of septic MOF.

Interleukin-4 plus tumor necrosis factor alpha augments the antigenicity of melanoma cells

Immune cytokines are important regulators of the immune response to neoplastic cells. We previously reported that interleukin 4 (IL-4) and either tumor necrosis factor alpha (TNF) or interferon gamma (IFN) synergistically inhibit melanoma cell growth and induce cell differentiation. In the present study we used various combinations of IL-4, IFN and TNF to enhance the antigenicity of melanoma cells. IL-4 plus TNF significantly increased the ability of melanoma cells to stimulate cytotoxic T cells (CTL) and act as targets of these CTL; IL-4 plus IFN was somewhat less effective, while TNF plus IFN was not as effective. IL-4 plus TNF also increased the expression of HLA class I and HLA-DR antigens on melanoma cells. The CTL lines examined in this study were CD3+CD4+ and oligoclonal. These preclinical results suggest that the immune response to melanoma whole-cell vaccines might be enhanced by pretreating vaccine cells with IL-4 plus TNF.

Functionally distinct elements are required for expression of the AMPD1 gene in myocytes

AMP deaminase (AMPD) is an enzyme found in all eukaryotic cells. Tissue-specific and stage-specific isoforms of this enzyme are found in vertebrates, and expression of these different isoforms is determined by selective expression of the multiple genes. The AMPD1 gene is expressed predominantly in skeletal muscle, in which transcript abundance is controlled by stage-specific and fiber type-specific signals. This enzyme activity is presumed to be important in skeletal muscle because a metabolic myopathy develops in individuals with an inherited deficiency of AMPD1. In the present study, cis- and trans-acting factors that control expression of AMPD1 have been identified. Two cis-acting elements located within 100 nucleotides of the transcriptional start site are required for muscle-specific expression of AMPD1. One element (-100 to -79) behaves like a tissue-specific enhancer, and it interacts with protein(s) found predominantly in nuclei of myoblasts and myotubes. This element is similar in sequence to an MEF2 binding motif, and it contains an A/T core that is essential for enhancer activity and binding of a nuclear protein(s). The second element (-60 to -40) has properties of a stage-specific promoter in that it is essential for muscle-specific expression of the AMPD1 promoter, does not confer muscle-specific expression on a heterologous promoter construct, and interacts with a protein(s) restricted to nuclei of differentiated myotubes. Interaction between these functionally distinct elements may be required for regulating the expression of AMPD1 during myocyte differentiation and in different muscle fiber types.

Alternative splicing: a mechanism for phenotypic rescue of a common inherited defect

Approximately 2% of Caucasians and African-Americans are homozygous for a nonsense mutation in exon 2 of the AMPD1 (AMP deaminase) gene. These individuals have a high grade deficiency of AMPD activity in their skeletal muscle. More than 100 patients with AMPD1 deficiency have been reported to have symptoms of a metabolic myopathy, but it is apparent many individuals with this inherited defect are asymptomatic given the prevalence of this mutant. Results of the present study provide a potential molecular explanation for "correction" of this genetic defect. Alternative splicing eliminates exon 2 in 0.6-2% of AMPD1 mRNA transcripts in adult skeletal muscle. Expression studies document that AMPD1 mRNA, which has exon 2 deleted, encodes a functional AMPD peptide. A much higher percentage of alternatively spliced transcripts are found during differentiation of human myocytes in vitro. Transfection studies with human minigene constructs demonstrate that alternative splicing of the primary transcript of human AMPD1 is controlled by tissue-specific and stage-specific signals. Alternative splicing of exon 2 in individuals who have inherited this defect provides a mechanism for phenotypic rescue and variations in splicing patterns may contribute to the variability in clinical symptoms.

Transfection of interleukin 2 gene into human melanoma cells augments cellular immune response

A preclinical model was used to determine if transfection of the interleukin 2 (IL-2) gene into human melanoma cells would augment the response of autologous and allogeneic peripheral blood lymphocytes (PBLs) from melanoma patients. IL-2 gene was transfected into three human melanoma cell lines; secretion of IL-2 from stable transfected cells was confirmed by enzyme-linked immunosorbent assay. The PBL response to these melanoma cells was then examined in a mixed-lymphocyte tumor reaction using PBLs from eight melanoma patients. The PBL response to autologous (P < 0.01) or human leukocyte antigen A cross-reactive (P < 0.05) transfected melanoma cells was significantly higher than it was to nontransfected melanoma cells. These data suggest that IL-2 gene transfection may be an important strategic approach to enhancing specific immune responses induced by a polyvalent melanoma cell vaccine.

Molecular cloning of AMP deaminase isoform L. Sequence and bacterial expression of human AMPD2 cDNA

Human AMPD2 cDNA clones have been isolated from T-lymphoblast and placental lambda gt11 libraries utilizing a previously cloned rat partial AMPD2 cDNA as the probe. Alignment analysis of all cDNA clones indicates the presence of intervening sequences in several placental isolates. This has been confirmed by sequencing human AMPD2 genomic clones. Intervening sequences can be removed from the cDNA clones by restriction with endonucleases at unique sites within the proposed open reading frame. This results in a 3292-base pair cDNA proposed to contain the entire AMPD2 open reading frame, which would encode a 760-amino acid polypeptide with a predicted subunit molecular mass of 88.1 kDa. Nucleotide and predicted amino acid comparisons with the 264 base pairs of proposed coding sequences in the rat AMPD2 cDNA demonstrate 91% similarity and identity, respectively. A comparison of the predicted human AMPD1 and AMPD2 polypeptides demonstrates homology in their C-terminal domains. Included in this region is the conserved motif, SLSTDDP, proposed to be part of the catalytic site of all AMP deaminases. In contrast, the predicted N-terminal domains of the human AMPD1 and AMPD2 polypeptides are unique. When placed in a prokaryotic expression vector, the human AMPD2 cDNA expresses AMP deaminase activity which can be precipitated with polyclonal antisera specific for isoform L.

Interleukin 4 receptor expression and growth inhibition of gastric carcinoma cells by interleukin 4

The expression of the interleukin 4 (IL-4) receptor (IL-4R) and effects of human recombinant IL-4 on human gastric carcinoma cell lines were studied. We demonstrated that IL-4 inhibited the growth of gastric carcinoma cells in a dose dependent manner (0.1-100 units/ml) in a [3H]thymidine incorporation proliferation assay. The gastric carcinoma cells varied in sensitivity to treatment with low dose IL-4. Treatment of cells with IL-4 altered the morphology of the cells to a "flattened" morphological shape resembling differentiation. The IL-4-mediated growth inhibition was significantly abrogated by neutralization of IL-4 with specific anti-IL-4 antibody. IL-4R expression on the cell surface was determined by assessing biotin-labeled IL-4 binding to cells using flow cytometry. IL-4R expression ranged from 5 to 85% of total cell population in the gastric carcinoma cell lines assessed. There was a positive correlation between the sensitivity to IL-4-mediated growth inhibition and IL-4R expression. By Northern blot analysis, we demonstrated that mRNA of IL-4R was expressed in the gastric carcinoma cells. Using in situ hybridization, we confirmed that IL-4R mRNA was expressed in the gastric carcinoma cell at the single cell level. By using a sensitive polymerase chain reaction technique, we demonstrated that gastric carcinoma cells expressed IL-4 mRNA, suggesting a possible autocrine loop. These studies indicate that IL-4 can significantly modulate gastric carcinoma cells that possess IL-4R. IL-4R on gastric carcinoma cells may be a potential therapeutic target site for IL-4-directed therapy.

Molecular basis of AMP deaminase deficiency in skeletal muscle

AMP deaminase (AMPD; EC 3.5.4.6) is encoded by a multigene family in mammals. The AMPD1 gene is expressed at high levels in skeletal muscle, where this enzyme is thought to play an important role in energy metabolism. Deficiency of AMPD activity in skeletal muscle is associated with symptoms of a metabolic myopathy. Eleven unrelated individuals with AMPD deficiency were studied, and each was shown to be homozygous for a mutant allele characterized by a C----T transition at nucleotide 34 (codon 12 in exon 2) and at nucleotide 143 (codon 48 in exon 3). The C----T transition at codon 12 results in a nonsense mutation predicting a severely truncated AMPD peptide. Consistent with this prediction, no immunoreactive AMPD1 peptide is detectable in skeletal muscle of these patients. This mutant allele is found in 12% of Caucasians and 19% of African-Americans, whereas none of the 106 Japanese subjects surveyed has this mutant allele. We conclude from these studies that this mutant allele is present at a sufficiently high frequency to account for the 2% reported incidence of AMPD deficiency in muscle biopsies. The restricted distribution and high frequency of this doubly mutated allele suggest it arose in a remote ancestor of individuals of Western European descent.

The increase of low density subpopulations and CD10 (CALLA) negative neutrophils in severely infected patients

We investigated the changes in polymorphonuclear leukocyte (PMN) subpopulations that accompany severe bacterial infection and examined their usefulness as a parameter for assessing the severity of infection. The Percoll density gradient was used to fractionate neutrophils into subpopulations of high density (1.09-1.10), intermediate density (1.08-1.09), and low density (1.07-1.08) with the majority of neutrophils from normal volunteers being of high density. By contrast, neutrophils from infected patients were of intermediate or low density, while those from severely infected patients showed a high percentage of the low density fraction with functional changes in lower chemotactic and beta-gulcuronidase activity. When each density subpopulation in the normal blood neutrophils was tested, low density PMNs had the lowest chemotaxis and minimal beta-glucuronidase activity. These results indicate that the increase in low density PMNs in patients with severe infection clearly reflects the functional impairment of PMNs. Flow cytometric analysis demonstrated that the neutrophils from severely infected patients had an decrease in CD10 expression. The percentage of CD10 positive PMNs correlated well with the severity of infection and with the clinical course of the patients. Thus, we conclude that PMN-density and CD10 expression change during severe bacterial infection, and that the measurement of PMN-subpopulations may be used to complement the clinical assessment of the severity of infections.

The anti Mac-1 monoclonal antibody inhibits neutrophil sequestration in lung and liver in a septic murine model

We investigated the mechanism by which leukocytes adhere to the pulmonary and liver microvascular endothelium in a septic murine model. After C57BL/6 mice were intraperitoneally (ip) injected with lipopolysaccharide (LPS), a striking peripheral leukocytopenia occurred as neutrophils accumulated rapidly in the lung and liver. When the anti-Mac-1 monoclonal antibody (mAb) was administered intravenously (iv) 2 hr before the ip administrated LPS, leukocytopenia and neutrophil accumulation in the lung and liver were inhibited significantly at 3 hr after the LPS injection. An immunofluorescence study revealed that Mac-1 expression on leukocytes from LPS-injected mice were greatly increased when compared to that of controls. Additionally, an in vitro assay demonstrated that LPS-activated serum increased neutrophil Mac-1 expression and neutrophil adhesion to the endothelial monolayer and that these phenomena are inhibited by pretreatment of neutrophils with anti-Mac-1 mAb. These results indicate that a marked increase in Mac-1 antigen expression by leukocytes plays a crucial role in striking neutrophil attachment to the vascular endothelium and is likely to be the cause of neutrophil accumulation in the lung and liver during endotoxemia.

[Immunological assessment of the pathogenesis of septic-MOF: relationship between complement activation and changes in neutrophil functions]

We investigated the pathogenesis of septic-MOF through the relationship between changes in neutrophil functions and degree of complement activation. The patients' neutrophils exhibited enhanced adherence to HUVEC, suppressed chemotaxis toward C5a, enhanced production of oxygen radicals and lysosomal enzymes. These changes in neutrophil functions related to complement activation elicited via classical pathway. Moreover, the activated complement participated in tissue injuries due to the cytolytic action of the terminal complement complexes such as membrane attack complex (MAC). In conclusion, the combination of neutrophil and complement was strongly associated with the pathogenesis of the septic-MOF.

Evidence that induction and regulation of lymphokine-activated killer (LAK) activity are mediated by changes in tumour-binding potential of lymphocytes after activation by interleukin-2 (IL-2)

The changes in the tumour-binding potential of human peripheral blood lymphocytes (PBL) after activation by interleukin-2 (IL-2) was investigated by directly counting the number of lymphocytes bound to lined hepatoma cell monolayers. A significant increase in the tumour-binding potential of PBL was found after activation by more than 100 U/ml of IL-2. Maximal tumour-binding potential was achieved at 1000 U/ml of activation, and an overdose of IL-2 activation slightly decreased this potential. These changes were almost exactly the same as the changes in anti-tumour cytotoxicity as measured by a 4-hr 51Cr-release assay. In addition, the kinetics of tumour binding by lymphokine-activated killer (LAK) cells was shown to be almost identical to that of tumour cell lysis. These results thus provide evidence that induction and regulation of LAK activity are mediated by changes in tumour-binding potential of lymphocytes after activation by IL-2.

Enhanced adherence activity of OK-432-induced peritoneal neutrophils to tumor cells correlates to their increased expression of CD11b/CD18

We previously found that activated peritoneal neutrophils adhered to tumor cells and destroyed them in the cancer ascites of patients who had received intraperitoneal (ip) OK-432 injection therapy. Since tight adhesion to the tumor cell is essential for effective neutrophil-mediated tumor cell destruction, we investigated the mechanism of peritoneal neutrophil adhesion to tumor cells, using a microplate adhesion assay. An in vitro study demonstrated that the adherence activity of the peritoneal neutrophils of patients who received OK-432 injection therapy to tumor cells increased greatly compared to that of blood neutrophils. The expression of the adhesion molecules (CD11a,b,c/CD18) of peritoneal neutrophils, which was determined by an immunofluorescence study, was about four times as much in CD11b and twice as much in CD11c and CD18 compared to that in blood neutrophils. In vitro OK-432 stimulation of normal blood neutrophils increased neither the adhesion to PLC nor the CD11b expression. The enhanced adherence activity of peritoneal neutrophils to tumor cells was significantly inhibited by pretreatment of the neutrophils with anti-CD11b and anti-CD18 monoclonal antibodies (mAb), but not by pretreatment with anti CD11a or anti-CD11c mAb. These results indicated that the increased adhesiveness of OK-432-induced peritoneal neutrophils to tumor cells was due to the enhanced expression of CD11b/CD18. We concluded that CD11b/CD18 molecules on OK-432-induced peritoneal neutrophils play a crucial role in the neutrophil adherence activity against tumor cells, and these results are the first demonstration in the field of human neutrophil function.

Adenylate deaminase. A multigene family in humans and rats

Multiple AMP deaminase (AMP-D) isoforms have been found in vertebrates, and tissue-specific inherited deficiencies of AMP-D have been described in two unrelated clinical syndromes suggesting there may be more than one AMP-D gene in higher eukaryotes. Using a newly isolated cDNA cloned from an adult rat brain library and a previously reported cDNA cloned from adult rat skeletal muscle, two linked AMP-D genes have been identified in rat and man. ampd1 is expressed at high levels in skeletal muscle of the adult rat. ampd2 is the predominant gene expressed in non-muscle tissues and smooth muscle of the adult rat, and it is also the predominant gene expressed in embryonic muscle and undifferentiated myoblasts. Both genes are expressed in cardiac muscle of the adult rat. The peptides encoded by these two genes have distinct immunological properties. The conservation of nucleotide sequence and exon/intron boundaries in these two genes suggests they arose by duplication of a common primordial gene around 150 million years ago.

Characterization of the human and rat myoadenylate deaminase genes

AMP deaminase is an ubiquitous enzyme in eukaryotic cells, and tissue-specific isoforms are produced in mammals by differential expression of the two genes which encode this enzyme activity as well as by alternative splicing of the primary transcript of one of these genes. Deficiency of this enzyme activity is one of the most common causes of metabolic myopathy in man. To provide a framework for understanding the molecular basis of this inherited disorder and the mechanisms responsible for regulating the expression of this enzyme activity, both the human and rat muscle-specific genes for AMP deaminase have been cloned and partially sequenced. Comparison of the two genes shows a high degree of conservation of sequence and structural organization. The two genes share the following characteristics: 1) both are approximately 20 kilobases in size, have identical exon/intron boundaries, and exhibit similar intron/exon structural organization; 2) the transcription start site is located at the same position in both genes, and comparison of 5'-flanking sequences reveals four highly conserved domains that together contain the information necessary for muscle-specific expression of a receptor cDNA; 3) coding sequences are 88% identical and the 5'-untranslated regions are 67% identical; 4) both genes have extremely short 3'-untranslated regions (13-17 nucleotides); 5) highly conserved intervening sequences of several hundred nucleotides surround most exon/intron boundaries. In situ hybridization and analysis of human-mouse somatic cell hybrids have localized the human gene (designated AMPD1) to chromosome 1 in the region p13-p21. The implications of these structural properties for identifying functional domains in the AMP deaminase peptide, regulation of expression of this gene, and inheritance of AMP deaminase deficiency are discussed.

Carcinoma in adenoma of the ampulla of Vater synchronous with cancer of the sigmoid colon

A 58-year-old Japanese man presented with early invasive adenocarcinoma within a papillotubular adenoma of the ampulla of Vater synchronous with advanced adenocarcinoma of the sigmoid colon. The colon had two additional adenomas. This hitherto unreported concomitance in the absence of familial polyposis coli is discussed.

A case of a postoperative aneurysm of the common hepatic artery which ruptured into the remnant stomach after a radical gastrectomy

A rare case of an iatrogenic aneurysm of the common hepatic artery which ruptured into the remnant stomach is described herein. The patient had undergone a radical gastrectomy with regional lymphadenectomy one month previously. The iatrogenic surgical trauma to the common hepatic artery incurred during the regional lymphadenectomy with the resection of the perivascular lymphatics and neural plexuses, was considered as the main cause responsible for the postoperative aneurysmal development.

Endobronchial non-Hodgkin's lymphoma

A 64-year-old man with non-Hodgkin's lymphoma suffered a complete collapse of the left upper lobe of the lung. Fibreoptic bronchoscopy demonstrated a large number of distinct polypoid tumours of the lymphoma in the trachea and bilateral sub-segmental bronchi. The left upper lobe bronchus was completely occluded by the tumours, which responded to the combination chemotherapy against the lymphoma. This report presents the seventh case of non-Hodgkin's lymphoma with multiple endobronchial tumours.

Two homozygous cases of erythrocyte pyruvate kinase (PK) deficiency in Japan: PK Sendai and PK Shinshu

Two new erythrocyte pyruvate kinase (PK) variants with severe nonspherocytic hemolytic anemia are presented. These cases are both considered to be homozygous because of the consanguineous marriages in their parents. Their erythrocyte PK's were characterized by the recommended methods of the International Committee for Standardization in Haematology (ICSH). These two variants have been named PK Sendai and PK Shinshu. PK Sendai showed a high K0.5S (phosphoenolpyruvate), was remarkably inhibited by ATP, and was thermolabile, while PK Shinshu demonstrated remarkably low enzyme activity and required a high level of fructose 1,6-diphosphate for activation.

Genetic analysis of adenosine deaminase expression in adult T-cell leukemia

We investigated the genetic basis for the increased adenosine deaminase (ADA) expression in adult T-cell leukemia (ATL). We found a correlation between the levels of ADA-specific mRNA and ADA immunoreactive protein in ATL. Southern blot analysis revealed no gene amplification or rearrangement of the ADA gene. These findings indicate that increased ADA expression in ATL cells reflects increased transcriptional activity for the ADA gene or increased stability of ADA mRNA.