Isolation and characterisation of antibodies which specifically recognise the peptide encoded by exon 7 (v2) of the human CD44 gene

Aims-Exon 7 of the human CD44 gene is overexpressed in many commonly occurring carcinomas. The aim of the study was to explore the diagnostic and therapeutic potential of this frequent abnormality.Methods-A new monoclonal antibody (mAb, M-23.6.1) and a polyclonal antibody (pAb,S-6127) to the corresponding antigen were raised by immunising mice and sheep, respectively, with a specially constructed fusion protein HIV2 (gp32)-CD44 exon 7.Results-Characterisation of mAb, M-23.6.1 by ELISA, western blotting, immunocytochemistry, and FACS analysis confirmed that it specifically recognises an epitope in the region between amino acids 19 and 33 of the peptide encoded by this exon. Western blotting experiments with two cell lines, RT112 and ZR75-1, known from RT-PCR data to be overtranscribing the exon, yielded a monospecific band of approximately 220 kDa, and immunocytochemistry showed discrete membrane staining on the same cell lines. Fluorescent antibody cell sorting (FACS) revealed binding to greater than 90% of the cells of each of these lines. Specificity of recognition of the antigen was shown by inhibition of the precise immunoreactivity typically seen in ELISA and Western blots, by pre-incubation with synthetic exon 7 peptide or fragments of it.Conclusions-The new antibodies will be useful tools for the further analysis of abnormal CD44 isoforms and their clinical implications.

Non-invasive detection of bladder cancer by identification of abnormal CD44 proteins in exfoliated cancer cells in urine

Aims-To investigate the expression of CD44 proteins in exfoliated urothelial cells and in tumour tissues from bladder cancer patients. A further objective was to evaluate the diagnostic potential of the changes observed in the expression of these proteins as a marker for non-invasive detection of bladder cancer.Methods-Naturally voided urine specimens were collected from 47 patients with bladder cancer or severe urothelial dysplasia (n=3) and from a control group of 43 people with no evidence of neoplastic disease. Exfoliated urothelial cells floating in the urine were pelleted by centrifugation and lysed, and their constituent proteins extracted. The pattern of expression of CD44 proteins in each sample was examined by western blot analysis using a monoclonal antibody, Hermes 3, which recognises an epitope on the polypeptide backbone of the CD44 protein. Immunohistochemical studies were performed on neoplastic (n=10) and normal (n=4) bladder tissue specimens which were snap frozen in liquid nitrogen before examination with antibodies to CD44 gene products (CD44s and CD44v6).Results-Western blot analysis revealed several high molecular weight CD44 isoforms > 160 kDa in urine cell lysates from 75% of patients with histologically confirmed bladder cancer and in two of the three patients with severe dysplasia. Such patterns were not detected in the urine cell pellets from any persons in the control group. Immunohistochemical studies of the tissue distribution of CD44s and CD44v6 showed that the differentiation and maturation of the epithelial cells in the normal bladder mucosa is accompanied by a decrease in CD44 protein expression. However, carcinoma cells overexpress standard and variant CD44 isoforms and continue to do so as they proceed through the thickened epithelial layer to the luminal surface and after they are shed into the urine.Conclusions-The abnormal expression of CD44 proteins in exfoliated cancer cells may be a useful marker for the noninvasive diagnosis of bladder cancer.

Involvement of JNK pathway in the promotion of the early stage of colorectal carcinogenesis under high-fat dietary conditions

BACKGROUND AND AIMS

The molecular mechanisms underlying the promotion of colorectal carcinogenesis by a high-fat diet (HFD) remain unclear. We investigated the role of the insulin-signal pathway and the c-Jun N-terminal kinase (JNK) pathway, which reportedly play crucial roles in insulin resistance, during colorectal carcinogenesis in the presence of hyperinsulinaemia induced by a HFD.

METHODS

Azoxymethane-induced aberrant crypt foci formation and cell proliferation in the colonic epithelium were compared between mice fed a normal diet (ND) and mice fed a HFD. A western blot analysis was performed to elucidate the mechanism affecting colorectal carcinogenesis by a HFD.

RESULTS

The number of aberrant crypt foci and the colonic epithelial cell proliferative activity were significantly higher in the HFD group than in the ND group. While the plasma insulin level was significantly higher in the HFD group than in the ND group, a western blot analysis revealed the inactivation of Akt, which is located downstream of the insulin receptor, in the colonic epithelia of the HFD group. On the other hand, JNK activity was significantly higher in the HFD group than in the ND group. A JNK specific inhibitor significantly suppressed the increase in epithelial cell proliferation only under a HFD, but not under a ND.

CONCLUSIONS

Colonic cell proliferation was promoted via the JNK pathway in the presence of a HFD but not in the presence of a ND. This novel mechanism may explain the involvement of the JNK pathway in the effect of dietary fat intake on colon carcinogenesis.

Predominant inhibition of Th1 cytokines in New Zealand black/white F1 mice treated with FK506

The T-helper 1/T-helper 2 (Th1/Th2) cell balance was examined in 6-month-old New Zealand black/white F1 (B/WF1) mice treated with an immunosuppressive agent, FK506. The survival rate of mice treated with 10 mg/kg/day of FK506 was 7/8, while that of those treated with 2.5 mg/kg/day was 5/8, and 4/8 after treatment for 8 weeks with placebo. Proteinuria, which was already positive in all mice before the treatment, in the seven of eight mice treated with 10 mg/kg/day remained mildly positive (< or = 1+), while seven of eight mice treated with 2.5 mg/kg/day and six of eight mice treated with the placebo showed severe proteinuria (> or = 2+). Pathological changes in the kidneys of mice treated with 10 mg/kg/day of FK506 were less severe than in mice treated with the placebo or 2.5 mg/kg/day of FK506. Expression of mRNA was unchanged for all cytokines determined in the groups treated with 2.5 mg/kg/day of FK506 or placebo. In contrast, expression of mRNA for interleukin (IL)-2, and interferon (IFN)-gamma was suppressed, while that for IL-4 and IL-10 was not suppressed in the group treated with 10 mg/kg of FK506. The serum levels of IgG-class anti-DNA antibodies, which had been elevated before the treatment, were suppressed--especially in the IgG2a subclass--and the deposition of IgG2a and IgG2b in the glomeruli was reduced in the group treated with 10 mg/kg/day of FK506 compared with the other groups. These findings suggest that an improvement in the lupus nephritis of 6-month-old B/WF1 mice induced by FK506 might be associated with a predominant inhibition of Th1 cytokine.

Gonadotrophin-releasing hormones agonist therapy increases peritoneal fibrinolytic activity and prevents adhesion formation after myomectomy

The aim of this study was to evaluate uterine adhesions after myomectomy and peritoneal fibrinolytic capacity in women treated with gonadotrophin-releasing hormone agonist (GnRHa) before surgery. A prospective observational study comprised 15 infertile women who underwent myomectomy. Before surgery, 10 were treated with buserelin acetate (900 microg/day) for 10-12 weeks followed by additional postoperative treatment with GnRHa for 4 weeks (GnRHa group) and five received no treatment (control group). Peritoneal fluid specimens were taken at the beginning of myomectomy and the adhesions were estimated by second-look surgery (caesarean section or laparoscopy). Levels of plasminogen activator (PA) and PA inhibitor (PAI) were determined by enzyme-immunosorbent assays. Pre- and postoperative GnRHa therapy significantly reduced adhesion formation compared with control groups (adhesion scores; 0.2 +/- 0.4 vs. 2 +/- 1, P<0.0001). GnRHa group showed a significant decrease in PAI level (P<0.0001) but no significant change in PA level, suggesting increased fibrinolytic capacity in peritoneal fluid from GnRHa-treated patients. These data suggest that GnRHa therapy is successful in preventing adhesion formation after myomectomy. GnRHa-induced shift to more fibrinolytic activity, mainly because of a decreased level of PAI, may play a critical role in the mechanism of the GnRHa's action on postoperative adhesion development.

Gi protein-mediated translocation of serine/threonine phosphatase to the plasma membrane and apoptosis of ovarian cancer cell in response to gonadotropin-releasing hormone antagonist cetrorelix

Serine/threonine protein phosphatase 2A (PP2A), a crucial enzyme in apoptosis control, has been demonstrated within the plasma membrane as well as in the soluble fraction. This study aimed to examine hormonal translocation of PP2A to the plasma membrane in gonadotropin-releasing hormone (GnRH)-responsive ovarian cancer cells. Apoptosis of ovarian cancer cell lines Caov-3 and SK-Ov-3 was quantified by nuclear morphology after staining with Hoechst 33342 dye. PP2A protein and activity in plasma membrane were assessed by immunohistochemical staining with PP2A-specific antibodies and by the measurement of the dephosphorylation of phosphopeptide highly selective for the PP2A, respectively. Incubation for 48 h with a GnRH antagonist cetrorelix caused parallel increases in the percentage of cells undergoing apoptosis and the membrane-associated PP2A activity; half-maximal effects occurred with 5 nmol/l cetrorelix. PP2A protein was also localised to the plasma membrane when the cell lines were exposed to cetrorelix. Pretreatment of the cells with pertussis toxin, but not cholera toxin, completely inhibited cetrorelix-stimulated apoptotic cell death and PP2A redistribution. These findings demonstrate that translocation of PP2A to plasma membrane is closely coupled to the onset of apoptosis in ovarian cancer cells exposed to GnRH antagonist. These GnRH-induced cellular events may be mediated through pertussis toxin-sensitive Gi protein-linked GnRH receptor.

Electrocardiographic criteria for predicting total occlusion of the proximal left anterior descending coronary artery in anterior wall acute myocardial infarction

BACKGROUND

Patients with occlusion of the left anterior descending coronary artery (LAD) proximal to both the first septal branch and the first diagonal branch may benefit most from early reperfusion therapy due to extensive area at risk.

HYPOTHESIS

The aim of the study was to examine whether 12-lead electrocardiograms (ECGs) in the acute phase of acute myocardial infarction (AMI) could identify total occlusion of the LAD proximal to both the first septal and the first diagonal branch.

METHODS

A 12-lead electrocardiogram was recorded on admission in 128 patients with anterior AMI within 12 h from symptom onset. Patients were divided into three groups according to the culprit lesion: 33 patients had total occlusion of the LAD proximal to both the first septal perforator and the first diagonal branch (Group P), in 51 it was proximal to either the first septal perforator or the first diagonal branch (Group D-a), and in 44 it was distal to both the first septal perforator and the first diagonal branch (Group D-b).

RESULTS

Sensitivity and specificity of a greater degree of ST-segment depression in lead III than that of ST-segment elevation in lead aVL were 85 and 95%, respectively, which was better than the results derived by all other ECG criteria (p< 0.001).

CONCLUSIONS

We conclude that a greater degree of ST-segment depression in lead III than that of ST-segment elevation in lead aVL is a useful predictor of proximal LAD occlusion in patients with anterior AMI.

Implications of the absence of ST-segment elevation in lead V4R in patients who have inferior wall acute myocardial infarction with right ventricular involvement

BACKGROUND

ST-segment elevation of > or = 1.0 mm in lead V4R has been shown to be a reliable marker of right ventricular involvement (RVI), a strong predictor of a poor outcome in patients with inferior acute myocardial infarction (IMI). However, patients with no ST-segment elevation in lead V4R despite the presence of RVI have received little attention.

HYPOTHESIS

The study was undertaken to study the clinical features of patients with no ST-segment elevation in lead V4R despite the presence of RVI, which means false negative, as such patients have received little attention in the past.

METHODS

We studied 62 patients with a first IMI, who had total occlusion of the right coronary artery (RCA) proximal to the first right ventricular branch and successful reperfusion within 6 h from symptom onset, to examine the implications of the absence of ST-segment elevation in lead V4R despite the presence of RVI.

RESULTS

A standard 12-lead electrocardiogram (ECG) and right precordial ECG (lead V4R) were recorded on admission, and three posterior chest ECGs (leads V7 to V9) were additionally recorded in 34 patients. Patients were classified according to the absence (Group 1, n = 18) or presence (Group 2, n = 44) of ST-segment elevation of > or = 1.0 mm in lead V4R on admission. Patients in Group 1 had a greater ST-segment elevation in leads V7 to V9 (2.9+/-2.4 vs. 1.4+/-3.0 mm. p < 0.05), a higher frequency of a dominant RCA (defined as the distribution score > or = 0.7) (72 vs. 11%, p < 0.001), and a higher peak creatine kinase level (3760+/-1548 vs. 2809+/-1824 mU/ml, p < 0.05) than those in Group 2.

CONCLUSIONS

In patients with IMI caused by the occlusion of the RCA proximal to the first right ventricular branch, no ST-segment elevation in lead V4R can occur because of concomitant posterior involvement. In such patients, the incidence of RVI may be underestimated on the basis of ST-segment elevation in lead V4R.

Adiponectin suppresses colorectal carcinogenesis under the high-fat diet condition

BACKGROUND AND AIMS

The effect of adiponectin on colorectal carcinogenesis has been proposed but not fully investigated. We investigated the effect of adiponectin deficiency on the development of colorectal cancer.

METHODS

We generated three types of gene-deficient mice (adiponectin-deficient, adiponectin receptor 1-deficient, and adiponectin receptor 2-deficient) and investigated chemical-induced colon polyp formation and cell proliferation in colon epithelium. Western blot analysis was performed to elucidate the mechanism which affected colorectal carcinogenesis by adiponectin deficiency.

RESULTS

The numbers of colon polyps were significantly increased in adiponectin-deficient mice compared with wild-type mice fed a high-fat diet. However, no difference was observed between wild-type and adiponectin-deficient mice fed a basal diet. A significant increase in cell proliferative activity was also observed in the colonic epithelium of the adiponectin-deficient mice when compared with wild-type mice fed a high-fat diet; however, no difference was observed between wild-type and adiponectin-deficient mice fed a basal diet. Similarly, an increase in epithelial cell proliferation was observed in adiponectin receptor 1-deficient mice, but not in adiponectin receptor 2-deficient mice. Western blot analysis revealed activation of mammalian target of rapamycin, p70 S6 kinase, S6 protein and inactivation of AMP-activated protein kinase in the colon epithelium of adiponectin-deficient mice fed with high-fat diet.

CONCLUSIONS

Adiponectin suppresses colonic epithelial proliferation via inhibition of the mammalian target of the rapamycin pathway under a high-fat diet, but not under a basal diet. These studies indicate a novel mechanism of suppression of colorectal carcinogenesis induced by a Western-style high-fat diet.

Relationships among changes of serum leptin concentration, leptin mRNA expression in white adipose tissue (WAT), and WAT fat-cell size in female Japanese black bears (Ursus thibetanus japonicus)

As a first step to study the relationship between fat accumulation and reproductive success in Japanese black bears ( Ursus thibetanus japonicus Schlegel, 1857) with the focus on leptin, we determined leptin cDNA sequences in the bears. Next, we studied the possibility of white adipose tissue (WAT) as a leptin secretion source by observing the changes of leptin mRNA expression in WAT by semiquantitative real-time reverse transcript – polymerase chain reaction, the index of WAT fat-cell size, and serum leptin concentration in pregnant bears. Then, based on our results, we discussed roles of leptin in those bears. The amino acid sequences of leptin from the bears were highly identical to that of other carnivores. The expression of leptin mRNA in WAT was detected from September to January, with a tendency to increase in late November and January; the relationship between changes in the index of WAT fat-cell size and those in serum leptin concentration was high (r = 0.55, P < 0.01), with an increase in both in mid-November. These results suggested that leptin was mainly secreted from WAT in bears and that serum leptin concentrations might reflect their nutritional condition. Moreover, leptin might serve as an indicator of their fat mass, which would affect their survival during hibernation and their reproductive success.

Brain natriuretic peptide detects cardiac abnormalities in mass screening

BACKGROUND

Plasma brain natriuretic peptide (BNP) is elevated in asymptomatic patients with various cardiac abnormalities. We tested the hypothesis that measuring BNP is useful for detecting asymptomatic patients with cardiac abnormalities who are not identified by conventional health check-up programmes.

MATERIALS AND METHODS

From 2001 to 2002, 6189 subjects (women 34.0%; mean age 56.6 years) underwent multiphasic health check-ups in our hospital, of which 4818 without cardiac abnormalities as revealed by the health check-up were enrolled in the present study. Their plasma concentrations of BNP were measured.

RESULTS

Plasma concentrations of BNP were higher than the normal reference upper limit of our hospital (21.3 pg mL(-1)) in 925 of the 4818 subjects. Echocardiography was performed in 471 subjects who were randomly selected from the 925 subjects with elevated BNP. Abnormal findings were detected in 174 subjects, comprising valvular heart disease in 83, systolic dysfunction in 10, diastolic dysfunction in 54, left ventricular hypertrophy in 41, left ventricular enlargement in 11, left atrial enlargement in 13 and paroxysmal atrial fibrillation in 3.

CONCLUSIONS

Since BNP measurement identifies additional subjects with cardiac abnormalities, it is useful for detecting asymptomatic cardiac abnormalities among apparently healthy subjects, and is suitable for use in high-quality mass screening.