Genetic alterations in rat colon tumors induced by heterocyclic amines

BACKGROUND

In rat colon tumors induced by the cooked food mutagens 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) and 2-amino-3-methylimidazo[4,5-f]quinoline (IQ), ras and p53 alterations are rarely detected. To investigate the roles of the APC gene and microsatellite instability (MI) in PhIP-induced colon carcinogenesis, mutations of the APC gene and alterations of microsatellites were examined.

METHODS

Complimentary DNA sequence of the rat APC gene were determined by polymerase chain reaction (PCR) using primers based on the human APC sequence. PCR-single strand conformation polymorphism (SSCP) analysis was performed using primers based on sequences of flanking introns and exon 15. Microsatellite alterations were also analyzed using 85 microsatellite sequences dispersed through most of the rat chromosomes.

RESULTS

Five mutations in the APC gene were detected in four of eight PhIP-induced rat colon tumors. All five mutations involved deletion of a guanine base in a 5'-GGGA-3' sequence. Only 2 of 13 IQ-induced colon tumors had mutations of the APC gene and these were base substitution mutations. Seven of eight PhIP-induced colon tumors had microsatellite alterations in at least one locus, whereas no alterations were observed in the IQ-induced colon tumors.

CONCLUSIONS

The specific 5'-GGGA-3' to 5'-GGA-3' mutation and MI demonstrated in this study are strong evidence of a mutational fingerprint of PhIP.

Sensitive flow-injection method with peroxyoxalate chemiluminescence detection combined with preparative high-performance liquid chromatography for determination of choline-containing phospholipids in human serum

A sensitive and rapid flow-injection analysis (FIA) of total choline-containing phospholipids (PLs) and a selective FIA method for the class assay of choline-containing PLs combined with preparative HPLC were described. The FIA method is based on peroxyoxalate chemiluminescence (PO-CL) detection of hydrogen peroxide enzymatically formed from choline-containing PL. The linear standard curves were obtained up to 1 nmol/20-microliters injection (r > 0.999) with the detection limits of 1.3-1.6 pmol at a signal-to-noise ratio of 2. The total amounts of choline-containing PLs in human serum were ranged from 1.63 to 3.19 mg/ml. The HPLC separation of choline-containing PLs was achieved with an aminopropyl-modified silica gel column using a mixture of acetonitrile-methanol-10 mM ammonium phosphate buffer pH 5.8 as eluent. The eluate corresponding to each choline-containing PL was collected, evaporated, dissolved in 0.1% Triton X-100 aqueous solution, and then injected into FIA system. The FIA method combined with preparative HPLC was applied to the assay of human serum.

[Recent progress of molecular oncology and its contribution to clinical gastroenterology]

Recent progress of molecular oncology has made it possible for us to begin to understand the molecular mechanism for tumor development. However, from a viewpoint of its diagnostic and therapeutic applications, it seems that we have just left a starting line. Even Ki-ras and p53 genes that have been most extensively analysed, their most important clinical significances are considered to be giving us pathogenetic informations at the present time. Of note, allelic loss of chromosome 18q was shown a significant prognostic factor for colorectal cancer patients in stage II. One of most important clinical applications of molecular oncology in near future in our country is diagnosis of hereditary cancer. Analyses of sporadic cases with mutations in hereditary cancer genes will be of special importance.

Detection of turkey rhinotracheitis virus from chickens with swollen head syndrome by reverse transcriptase-polymerase chain reaction (RT-PCR)

We developed a sensitive and specific method, reverse transcriptase-polymerase chain reaction (RT-PCR) method, for detection of turkey rhinotracheitis virus (TRTV). Two sets of primers were designed from F protein gene sequence of TRTV 3B strain. Sensitivity of detection by nested PCR with the primers corresponded to 0.4 TCID50. Applying this method to a field case of swollen head syndrome (SHS), TRTV could be detected directly from chicken trachea and turbinates. It was identified that this method was very useful to examine the relation of TRTV and SHS.

Purification and refolding of recombinant human proMMP-7 (pro-matrilysin) expressed in Escherichia coli and its characterization

Human matrix metalloproteinase-7 (MMP-7 = matrilysin) was overproduced in Escherichia coli as a recombinant zymogen (31 kDa), the C-terminus of which bears artificial hexa-histidines. Most of the enzyme was isolated from the insoluble fraction of the cell lysate and purified by a single step using Ni-NTA resin after solubilization of the precipitates with 8 M urea solution. The resin-bound recombinant protein was refolded into a form that is activatable by p-amino-phenylmercuric acetate in an autocatalytic manner. The activated enzyme cleaved a synthetic peptide substrate at the reported site for MMP-7. Digestion of carboxymethylated transferrin (a natural substrate of MMP-7) by the recombinant proteinase generated fragments with the same peptide map as in the case of native purified MMP-7. The autocatalytic activation and enzyme reaction were entirely dependent on the presence of calcium and zinc ions. The enzyme activity to cleave carboxymethylated transferrin was inhibited by tissue inhibitors of metalloproteinases-1 and -2, MMP-specific inhibitors. The activity of the recombinant MMP-7 was also inhibited by a synthetic peptide derived from a part of the cysteine switch that maintains the zymogen in an inactive state. Thus, we report here a simple means of preparing a large quantity of recombinant proMMP-7 that can be used to study the activation mechanism and to screen synthetic inhibitors.

Soluble intercellular adhesion molecule-1 and soluble E-selectin levels in patients with atopic dermatitis

The serum levels of soluble intercellular adhesion molecule-1 (sICAM-1) and soluble E-selectin (sE-selectin) were determined by double determinant immunoassay (DDIA), in 37 patients with atopic dermatitis (AD) and 31 age- and sex-matched healthy control subjects. Both sICAM-1 and sE-selectin levels were significantly higher in patients with AD than in healthy controls (P < 0.01), and were correlated with disease severity. A longitudinal study of patients with AD revealed that the levels of sICAM-1 decreased in those in whom symptoms improved. The sICAM-1 levels were significantly correlated with those of sE-selectin. Our studies suggest that such high levels of serum sICAM-1 and sE-selectin may affect the immune response in patients with AD. The levels of sICAM-1 and sE-selectin may be a useful immunological parameter for monitoring disease activity in AD.

Progesterone stimulates the induction of human endometrial CD56+ lymphocytes in an in vitro culture system

An unusual population of large granular lymphocytes (LGL) with the surface phenotype CD56(bright+)/CD16-/CD3- increases in the human endometrium during the late secretory phase and early pregnancy. To identify the factor(s) that induces CD56+ LGL in the human endometrium, we isolated endometrial leukocytes from nonpregnant human endometrium and investigated changes in CD56+ cells during culture with various factors. Isolated endometrial leukocyte-rich fraction and peripheral blood mononuclear cells were cultured for 6 days in the presence of progesterone, estradiol, PRL, or hCG, then nonadherent cells were collected and examined immunocytochemically. Endometrial leukocyte-rich fractions were composed of leukocytes and endometrial stromal cells, and 53.2 +/- 5.8% of them expressed CD45 antigen before culture. Therefore, leukocytes and endometrial stromal cells were cocultured in these endometrial leukocyte-rich fraction cultures. The percentage of CD56+ cells in endometrial leukocyte-rich fractions cultured with progesterone was significantly higher than that in fractions without progesterone. On the other hand, estradiol, PRL, and hCG did not significantly induce CD56+ cells in endometrial leukocyte-rich fractions. There was no significant difference in the percentage of CD56+ cells between peripheral blood mononuclear cell cultures with and without progesterone. These findings suggest that progesterone is an important factor for the in situ proliferation or differentiation of CD56+ LGL in human endometrium.

A human/mouse chimeric monoclonal antibody against intercellular adhesion molecule-1 for tumor radioimmunoimaging

A mouse-human chimeric antibody for intercellular adhesion molecule-1 (ICAM-1) was established by using heavy chain loss mouse mutant hybridoma and human immunoglobulin expression vector. The HA58 hybridoma secreted anti-ICAM-1 monoclonal antibody (MoAb) (IgG1, kappa). The gene of the mouse variable region of heavy chain was amplified and cloned by the polymerase chain reaction technique directly from the HA58 hybridoma RNA. The variable region of heavy chain was joined with an expression vector which contains human gamma 1 constant gene. The expression vector was transfected into heavy chain loss mutant cells HA58-7, which produced only murine immunoglobulin light chains. The resultant chimeric MoAb HA58, chHA58, retained full-binding reactivity to ICAM-1 compared with murine HA58 parental antibody. The chimeric MoAb chHA58 showed little antibody dependent cell-mediated cytotoxic activity against cultured tumor cells. Biodistribution studies with 99mTc-labeled chHA58 in nude mice bearing human gastric carcinoma JRST cells demonstrated that the tumor-blood ratio was 1.55 at 18 h after injection, when the tumors were clearly visible in gamma scintigraphy. These data suggest that chHA58 may be of practical use for radioimmunoimaging of a wide variety of tumors.

Non-traumatic arteriovenous fistulas of the scalp treated by a combination of embolization and surgical removal

Three patients with non-traumatic arteriovenous fistulas (AVFs) of the scalp were treated by embolization using acrylate glue through the transarterial route or by direct puncture of the lesions and then surgical resection. Complete cure was achieved in all three patients. Selective angiography is indispensable in the correct diagnosis of scalp AVFs. Embolization facilitates surgical removal when necessary, and this combination is the treatment of choice for scalp AVFs.

[Etiology of prostate cancer and significance of screening for early prostate cancer]

The incidence and mortality rate of prostate cancer in Japan are lower than in Western countries. Though studies of migrating populations would suggest that dietary or environmental factors may influence the etiology of the disease. The Westernized lifestyle after the Second World War may have influenced the increasing incidence of this disease in Japan. The screening by prostate specific antigen (PSA) on an asymptomatic healthy population can detect early prostate cancer. It is expected that the mortality may be decreased through such a system. However, some scientists hesitate to perform an aggressive program of early detection because of the possibility of latent cancer detection, the difficulty of distinguishing between clinically important and unimportant cancer, a high false positive rate to detect early stage cancer, and the lack of well-executed randomized prospective studies. Current clinical studies of the prostate cancer have demonstrated that the unimportant cancer detection rate by PSA was less than 10%. When a 4.0 ng/ml PSA cut-off value is applied for early detection, the false positive rate is approximately 80%. It is important to make subjects examined by the screening program aware of its the meaning. However, there is not a complete and cost-effective diagnostic modality to detect early prostate cancer. Moreover, it is confirmed that radical prostatectomy improves survival, but it has not been confirmed to improve the mortality based on population. We propose that well-executed randomized studies by the end point of the survival, cancer death rate, cost effective, QOL and etc. are urgently needed.

Microsatellite instability and loss of heterozygosity on chromosome 10 in rat mammary tumors induced by 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine

Microsatellite instability (MI) and loss of heterozygosity (LOH) were examined in mammary tumors induced in Sprague-Dawley x F344 F1 female rats by 2-amino-l-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP). Examination of 62 microsatellite loci revealed MI in nine of 15 (60%) PhIP-induced mammary tumors, and five of these MI-positive tumors had mutations in more than one microsatellite locus. In contrast, two of 12 (17%) 7,12-dimethylbenz[a]anthracene (DMBA)-induced mammary tumors were MI positive but had mutations at only one locus each. Further, by using 37 polymorphic markers specific LOH was observed in four of 15 PhIP induced mammary tumors on distal parts of rat chromosome 10, which is homologous to human chromosome 17q with no background level of LOH. Similarly, DMBA-induced mammary tumors showed specific LOH on the same region of chromosome 10. These data suggest that mismatch-repair deficiency and loss of chromosome 10 are involved in carcinogenesis of PhIP-induced rat mammary tumors.

[New mucin core protein genes and their clinical application]

Recent molecular biological approach has revealed the primary structure of some mucin core proteins. Most prominent characteristic is tandemly repeated sequences. cDNA cloning of 8 kinds of mucin core proteins, MUC1-7, have thus been performed. Among them, the entire structure was revealed on MUC1,2 and 7. MUC1 is a type I transmembrane protein with a large number of tandem repeat consisting of 20 amino acids. We have found that mouse MoAb MUSE11 against adenocarcinoma, which detects circulating MUC1 in patients with gastrointestinal and pancreatic cancers, recognizes part of the tandem repeat of MUC1 using synthetic peptides. We have transfected MUC1 cDNA to some cell lines, and they indicated that cell-cell and cell-matrix adhesion, growth rate and reactivity with growth factor were suppressed. To date, some of the MoAbs to adenocarcinoma have been shown to react with PDTRP sequence in the tandem repeat of MUC1 (MUC1 epitope), suggesting that MUC1 epitope could be highly immunogenic in human. Recently, cytotoxic T-cells against MUC1 epitope were established from breast and pancreas cancer patients. We also induce those T-cells from the patient with multiple myeloma. Interestingly, CTL functions in an HLA-unrestricted manner, and may be of use an adoptive immunotherapy. MUC2, a large secretory type mucin, cysteine-rich subdomains located both upstream and downstream of its central repetitive region, and these subdomains have sequence similarity with von Willebrand factor. We have shown that anti MUC2 core-protein MoAb CCP58 reacts intestinal metaplasia and cancer in stomach, but not normal gastric mucous membrane. Recently we established a new monoclonal antibody against purified deglycosylated gastric mucin. This antigen was expressed in the deep portion of metaplastic glands and cancers in the stomach. Two cDNA clones coding for this antigenic molecule were obtained.

Oxygen binding properties of Eudistylia vancouverii chlorocruorin and its dodecamer subunit

The oxygen equilibrium curves of the extracellular chlorocruorin of the polychaete Eudistylia vancouverii and its dodecamer subunit were determined over the pH range from 7.1 to 8.1 and in the presence and absence of 100 mM Mg2+. Although the chlorocruorin has a very low oxygen affinity, high cooperativity and a moderate alkaline Bohr effect (P50 = 145 mmHg, nmax = 6.9, phi = -0.44 at pH 7.1 and 25 degrees C), the dodecamer subunit has higher affinity and lower cooperativity and Bohr coefficient (P50 = 58 mmHg, nmax = 1.7, phi = -0.22). The presence of 100 mM Mg2+ increased the oxygen affinity and cooperativity of the chlorocruorin but had no significant effect on the dodecamer subunit. The oxygen binding properties of the chlorocruorin reassociated subsequent to complete dissociation in 4 M urea at neutral pH were similar to the properties of the dodecamer and not to those of the native chlorocruorin. Fitting to the Monod-Wyman-Changeux allosteric model gave KT of 0.0013 mmHg-1, Kr of 0.22 mmHg-1 and L(o) of 2.5 x 10(13) together with a size of the allosteric unit, N = 9.

Boron trifluoride-etherate (Lewis acid) as an efficient acid at cyclization/cleavage reaction of D/L-amino acids affording the retention of their original configuration in the Edman sequencing method of peptides

Boron trifluoride-etherate (BF3), one of the Lewis acids, was found to be an efficient acid in the Edman sequencing method, affording the retention of the N-terminal amino acid configuration at the cyclization/cleavage reaction from peptides. Examples for the sequencing of D-Leu-Gly and L-Pro-L-Leu are described, utilizing 7-N,N-dimethylaminosulphonyl-4-(2,1,3-benzoxadiazolyl) isothiocyanate (DBD-NCS) as a fluorogenic Edman reagent. The peptide labelled with DBD-NCS was cyclized/cleaved with 1% BF3 in dichloroethane containing 0.02% ethanethiol at 50 degrees C for 5 min. The resultant DBD-thiazolinone (TZ)-amino acid was separated on a phenylcarbamoylated cyclodextrin column with fluorometric detection at 524 nm with excitation at 387 nm. DBD-TZ-amino acids thus obtained showed remarkable retention of their configuration of alpha-carbon atoms of amino acids (DBD-TZ-L-Leu; 3%, -D-Pro; 6%). Even after 30 min of the cyclization/cleavage reaction at 50 degrees C, DBD-TZ-amino acids retained their configuration to the same degree. On the other hand, DBD-TZ-amino acid obtained by cyclization/cleavage reaction with TFA at 50 degrees C for 5 min was racemized to a great extent (DBD-TZ-L-Leu; 31%, -D-Pro; 48%). BF3 should be the most recommendable acid at the cyclization/cleavage reaction for amino acid sequence and configuration determination of peptides containing D-amino acid residues.

[Tricuspid valve closure for pulmonary atresia with intact ventricular septum]

Tricuspid valve closure was performed on four children who had pulmonary atresia with intact ventricular septum. All of them had major right ventricle-coronary communications and severely hypoplastic right ventricle under 30% of normal right ventricle volume. Their coronary circulations were not right ventricle dependent. All of four patients survived tricuspid valve closure. Three children were performed Fontan procedure. One child, with severe change in her coronary arteries preoperatively, once improved her myocardial ischemia in early stage after tricuspid valve closure, however, the myocardial ischemia progrssed in one year later and died suddenly three years and five months after tricuspid valve closure. Three survivors remained good condition in their left ventricle function postoperatively. In this study, we investigated changes in LVEF, LVEDVI, LVEDP and mitral regurgitation as indicators of left ventricle functions through tricuspid valve closure. It revealed that tricuspid valve closure had advantages in preservation of left ventricle function and in preparation for Fontan procedure consequently.

Isolation and partial structure of a unique lipophilic peptide, VAP peptide, from the heads of male silkworm moths

A new lipophilic peptide was isolated from the MeOH-CH2Cl2 extract of adult heads of the male silkworm, Bombyx mori, by monitoring the diapause egg-inducing activity. Partial amino acid sequencing (1-55) revealed this peptide to be a unique type having a high content of lipophilic amino acids, Val, Ala, and Pro, and many repeating sequences. The compound was thus named VAP peptide.

[Functions of mucin molecules in gastrointestinal cancer]

Studies about the function of mucin molecules as surface molecule of adenocarcinoma of gastrointestinal tract had just started, and several important function of mucins had been revealed. In the process of the malignant transformation, class of the expressed mucin core protein and content of glycochain of mucin molecule was changed. Changes of glycoprotein of mucin molecule during transformation affect immunogenesity, tumorigenesity, metastatic ability and sensitivity for anti-cancer drugs. Glycosylated mucin acts important roles during metastatic sequence and prognosis of the gastrointestinal cancer was collerated with expression of immatured mucin of cancer cells. A type of mucin with immature type of glycochain, MUC1, had a protective function for cytotoxicity, e.g. natural killer cell and cytotoxic T-cell, and deglycosilation of MUC1 sensitize cancer cells for cytotoxicity. And MUC1 reduce sensitivity for anti-cancer drugs and MUC1 was glycosilated during process to get resistance for anti-cancer drug. The functions of mucin molecules is not fully revealed, but further studies will indicate importance of mucin molecules in tumor progression.

Detection of antiendometrial antibodies in patients with endometriosis by cell ELISA

PROBLEM

To determine whether infertile patients with endometriosis have serum antiendometrial antibodies.

METHODS

Sera from 40 infertile patients with or without endometriosis were tested by cell enzyme-linked immunosorbent assay (ELISA), in which endometrial cancer cells were used as endometrial antigens, and uterine cervix cancer cells as control antigens. As a negative control, eight healthy adult males were included. The level greater than the mean +/- 2 standard deviations (SD) of the male control group was judged positive.

RESULTS

The mean value of antiendometrial antibody level was significantly higher in patients with endometriosis than in those without endometriosis (ANOVA, P < 0.01). The frequency of antiendometrial antibody-positive patients was also higher in the former than in the latter (chi 2 test, P < 0.05). However, when uterine cervix cancer cells were used as antigens, no difference was observed in the mean antibody levels or in the positive rates between the two groups.

CONCLUSIONS

Endometriosis seems to be associated with autoantibody production against the endometrium-related antigen(s).

Expression of CD10/neutral endopeptidase in normal and malignant tissues of the human stomach and colon

The expression of common acute lymphoblastic leukemia antigen (CALLA; CD10), which is identical to neutral endopeptidase (NEP, EC3.424.11), was examined in the malignant and adjacent noninvaded tissues of the human stomach and colon (n = 27). All of 27 normal and 18 well or moderately differentiated adenocarcioma tissue specimens were positive for monoclonal antibody (mAb) NL-1 against CD10/NEP, whereas the expression level was clearly decreased in all of 9 specimens of poorly differentiated adenocarcinoma. In addition, all of 7 gastric or colorectal carcinoma cell lines tested showed decreased expression of CD10/NEP. Sodium dodecylsulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and Western blot analysis of the crude antigen J5 from the normal colon tissue lysate by mAb J5 detected a single band of approximately 100 kDa that was consistent with that of NALM-6 cells used as a positive control. These findings suggest that CD10/NEP is expressed in normal epithelial cells of the human stomach and colon, whereas the expression level is decreased in the poorly differentiated type of adenocarcinoma.

Matrix metalloproteinase 9 (gelatinase B) is expressed in multinucleated giant cells of human giant cell tumor of bone and is associated with vascular invasion

Human giant cell tumor (GCT) consists of multinucleated giant cells and mononuclear stromal cells, and is characterized by frequent vascular invasion without distant metastases. To study the role of matrix metalloproteinases (MMPs) in the vascular invasion, we examined production of MMP-1 (tissue collagenase), -2 (gelatinase A), -3 (stromelysin-1), -9 (gelatinase B), and tissue inhibitors of metalloproteinases (TIMP-1 and -2) in GCT. MMP-9 was highly and predominantly expressed in giant cells by both immunohistochemistry and in situ hybridization. Expression of other MMPs was also observed in some cases but was inconstant. Sandwich enzyme immunoassays demonstrated that MMP-9 is the predominant MMP secreted by GCT. There was a definite imbalance between the amounts of MMP-9 and those of TIMPs in the culture media of GCT, leading to detectable gelatinolytic activity in an assay using 14C-gelatin. Gelatin zymography demonstrated the main activity at about 90 kd, which was identified as the zymogen of MMP-9 by immunoblotting. Immunohistochemistry for type IV collagen and laminin, major basement membrane components, showed that disappearance of the proteins is closely associated with MMP-9-positive giant cells. These results indicate the production of MMP-9 by multinucleated giant cells and suggest that the metalloproteinase may contribute to proteolysis associated with vascular invasion and local bone resorption in human GCT.