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Biomedical subjects

K Handa

Publications and source records attributed to K Handa.

At least 37 records · Page 2Linked to original sources
PubMed2000

Glycosylation effect on membrane domain (GEM) involved in cell adhesion and motility: a preliminary note on functional alpha3, alpha5-CD82 glycosylation complex in ldlD 14 cells.

Laminin (LN)- or fibronectin (FN)-dependent adhesion in Krieger's ldlD 14 (D14) cells is enhanced significantly in the presence vs absence, of galactose (Gal), whereas LN- or FN-induced haptotactic cell motility is barely affected unless cells express CD82 by its gene transfection (cells termed D14/CD82). The effect of CD82 on LN- or FN-induced motility is based on its ability to associate with alpha3 or alpha5 integrin to form a complex associated with a low-density lipid membrane domain (termed GEM or GSD). Complex formation is greatly affected by N-glycosylation of both integrin and CD82, as well as by concurrent GM3 ganglioside synthesis. The effect of glycosylation on alpha5-CD82 complex was also studied in D14 cells expressing mutant CD82, defective in all three N-glycosylation sites. LN-induced motility was greatly inhibited, whereas FN-induced motility was enhanced, with complete N-glycosylation in D14/CD82 cells in Gal-added medium, whereby alpha5-CD82 complex formation did not occur or occurred at a minimal level. Both LN- and FN-induced motility were inhibited when N-glycosylation was impaired, or N-glycosylation of CD82 was deleted, whereby alpha5-CD82 complex formation occurred strongly. Thus, glycosylation profoundly affects interaction of integrin with CD82, leading to significant inhibition or promotion of cell motility.

Animals↗
PubMed2000

Cigarette smoking, CYP1A1 MspI and GSTM1 genotypes, and colorectal adenomas.

Cigarette smoking has been related to increased risk of colorectal adenomas, but the underlying mechanisms are unknown. Genetic polymorphisms are known for enzymes involved in the activation of polycyclic aromatic hydrocarbons and other tobacco-related carcinogens. Polycyclic aromatic hydrocarbons are activated by cytochrome P4501A1 (CYP1A1) and detoxified by glutathione S-transferases. We investigated the relation of CYP1A1 MspI and GSTM1 genotypes to the risk of colorectal adenomas with special reference to interaction with cigarette smoking among 205 cases of colorectal adenomas and 220 controls with normal total colonoscopy in a male Japanese population. Cigarette smoking was strongly associated with increased risk of colorectal adenomas. Overall, neither the CYP1A1 MspI genotype nor the GSTM1 genotype was related to colorectal adenomas. A significant trend for increased risk of colorectal adenomas associated with smoking was observed for each of the CYP1A1 MspI genotypes, and the increasing trends did not differ by MspI genotype. The positive association between smoking and colorectal adenomas did not vary much with GSTM1 genotypes. Among former and current smokers, adenoma risk did not differ according to the combination of CYP1A1 MspI and GSTM1 genotypes. CYP1A1 MspI and GSTM1 genotypes do not seem to modify the risk of colorectal adenomas associated with cigarette smoking.

Adenoma↗
PubMed2000

Glycosylation affects translocation of integrin, Src, and caveolin into or out of GEM.

Endogenous GM3 synthesis and full N-glycosylation in membrane receptors occurred in "4-epimerase-less" ldlD (Krieger's CHO mutant) cells cultured in Gal-containing medium, whereby components of detergent-insoluble, low-density, buoyant membrane fraction, termed "glycolipid-enriched microdomain (GEM)," varied significantly by translocation into or out of GEM. Integrins alpha3 and alpha5 were translocated into GEM in the presence of 0.5 or 0.25% Triton X-100, particularly in the absence of Gal, whereby integrins are underglycosylated and GlcCer is the major glycolipid component in GEM. Src family kinase was translocated into and enriched in GEM fractions when prepared in 0.5 or 0.25% Triton X-100 from cells grown in Gal-containing medium, whereby GM3 synthesis is induced. In contrast, caveolin is highly enriched in GEM when GM3 synthesis does not occur, and is translocated into high-density membrane fraction when GM3 synthesis occurs. The results suggest that levels of key molecules controlling cell adhesion and signaling are defined by translocation into or out of GEM, which depends on glycosylation state.

Animals↗
PubMed2000

Reconstitution of membranes simulating "glycosignaling domain" and their susceptibility to lyso-GM3.

GM3 ganglioside at the surface of mouse melanoma B16 cells is clustered and organized with signal transducer molecules c-Src, Rho A, and focal adhesion kinase (FAK) to form a membrane unit separable from caveolae, which are enriched in cholesterol and caveolin but do not contain GM3 or the above three signal transducers. The GM3-enriched membrane units are involved in GM3-dependent cell adhesion coupled with activation of c-Src, Rho A, and FAK and are termed the "glycosphingolipid signaling domain" or the "glycosignaling domain" (GSD). In order to assess the essential components that display GSD function, membranes with properties similar to those of GSD were reconstituted using GM3, sphingomyelin, and c-Src, with or without other lipid components. The reconstituted membrane thus prepared displayed GM3-dependent adhesion to plates coated with Gg3 or anti-GM3 antibody, resulting in enhanced c-Src phosphorylation (c-Src phosphorylation response). This response in reconstituted membrane depends on GM3 concentration and was not observed when GM3 was absent or replaced with other gangliosides GM1 or GD1a, or with LacCer. The GM3-dependent c-Src phosphorylation response was enhanced when cholesterol and phosphatidylcholine were added. Although GM3, sphingomyelin, and c-Src are essential for GSD function, a small quantity of cholesterol and phosphatidylcholine may act as an auxiliary factor to stabilize membrane. GSD function in terms of GM3-dependent adhesion and signaling was blocked in the presence of lyso-GM3 or its analogue but not psychosine, lactosyl-sphingosine, or lyso-phosphatidylcholine. Such susceptibility of reconstituted GSD to lyso-GM3 and other lyso compounds is the same as GSD of original B16 cells. Thus, functional organization of the reconstituted membrane closely simulates that of GSD in B16 cells, which is based on clustered GM3 organized with c-Src as the essential components.

Animals↗
PubMed2000

Methylenetetrahydrofolate reductase polymorphism and risk of colorectal adenomas.

A homozygous mutation at bp 677 in the gene for the methylenetetrahydrofolate reductase (MTHFR) was previously shown to be associated with a decreased risk of colorectal cancer. We examined the relation between the MTHFR genetic polymorphism and risk of colorectal adenoma in Japanese men using 205 cases of colorectal adenomas and 220 controls of normal total colonoscopy. The homozygous mutation was not measurably associated with colorectal adenomas. The findings corroborate the lack of an association between the MTHFR genotype and colorectal adenomas, but do not deny the possibility that the genotype may be involved in the late stage of colorectal carcinogenesis.

Adenoma↗
PubMed2000

Dust exposure and lung cancer mortality in tunnel workers.

The eastern part of the Toyama Prefecture in Japan is one of the high-incidence areas of silicosis due to tunnel construction. In 1977 and 1978, we conducted a questionnaire survey primarily concerning the occupational history of all male inhabitants over 30 years of age living in five villages in this area and found 603 tunnel workers and inhabitants without dust history. These workers have been followed up to 1994 for about 17 to 18 years to clarify the relationship between tunnel work and lung cancer mortality. The SMR's of workers with dust exposure for all causes and for lung cancer was 120 and 188, respectively, which was significantly higher than those of the Japanese general population. After adjustment for age and smoking habits using Cox's proportional hazard model, tunnel work showed a significant relationship to mortality. Mortality risk ratio of tunnel workers was 2.15 compared with that of inhabitants without dust exposure history.

Adult↗
PubMed1999

Contact-dependent growth inhibition and apoptosis of epidermal growth factor (EGF) receptor-expressing cells by the membrane-anchored form of heparin-binding EGF-like growth factor.

Heparin-binding epidermal growth factor-like growth factor (HB-EGF) transduces mitogenic signals through the EGF receptor (EGFR). There are two forms of HB-EGF, the membrane-anchored form (pro-HB-EGF) and the soluble form (sHB-EGF). We studied the biological activity of pro-HB-EGF by using a model in which pro-HB-EGF-expressing effector cells was co-cultured with EGFR-expressing target cells. The DER cell, an EGFR-expressing derivative of the interleukin-3-dependent hematopoietic 32D cell line, grows well in the presence of EGF or sHB-EGF without IL-3. When DER cells were co-cultured on a monolayer of Vero-H cells overexpressing pro-HB-EGF, growth inhibition and subsequent apoptosis were induced in the DER cells even in the presence of excess amounts of EGF or sHB-EGF. Such growth inhibition of DER cells was abrogated when specific antagonists for pro-HB-EGF were added in the culture medium or when direct contact of DER cells with Vero-H cells was prevented, indicating that pro-HB-EGF is involved in this inhibitory effect. Pro-HB-EGF-induced apoptosis of DER cells was also observed even in the presence of IL-3. This rules out the possibility of simple competition between soluble EGFR ligands and pro-HB-EGF. Moreover, 32D cells expressing EGFR mutant composed of the extracellular and the transmembrane domain of EGFR and the cytoplasmic domain of erythropoietin receptor did not undergo apoptosis by co-culture with Vero-H cells, indicating that the inhibitory signal induced by pro-HB-EGF-expressing Vero-H cells is mediated to DER cells via EGFR and that the cytoplasmic domain of EGFR is essential for pro-HB-EGF-induced apoptosis. From these results, we concluded that pro-HB-EGF has unique biological activity through cell-cell contact that is distinct from the activity of sHB-EGF.

Animals↗
PubMed1999

Expression of cell cycle markers in colorectal carcinoma: superiority of cyclin A as an indicator of poor prognosis.

Our aim was to analyze the relationship between the proliferative activity of cancer cells, assessed using some cell cycle markers, and clinicopathological factors in colorectal carcinoma patients. Immunostaining for Ki-67 (pan-cell cycle marker), cyclin D1 (G1-phase marker) and cyclin A (S- to G2-phase marker), and in situ hybridization for histone H3 mRNA (S-phase marker) were carried out. Immunoreactivity was evaluated semiquantitatively using a scoring system to calculate a staining index (SI). The expression of cyclin D1, histone H3 mRNA and cyclin A correlated significantly with Ki-67 antigen expression. The SIs of Ki-67, cyclin A and histone H3 mRNA were significantly higher in patients > or = 65 years of age than in those < 65. The SIs of Ki-67 and cyclin D1 in poorly differentiated adenocarcinomas were significantly higher than in the other tumor types. Furthermore, the SI of cyclin D1 in carcinomas with lymph node metastasis was higher than in carcinomas without metastasis and was higher in advanced carcinomas than early carcinomas. The overall survival was significantly lower in patients with cyclin A overexpression than in those without. Multivariate analysis indicated that cyclin A overexpression is an independent prognostic factor in patients with colorectal adenocarcinoma. Our results indicate that cyclin D1 overexpression correlates with poor adenocarcinoma differentiation and tumor progression, and cyclin A overexpression is a superior indicator of poor prognosis compared with the other cell cycle markers tested.

Adult↗
PubMed1999

Motility inhibition and apoptosis are induced by metastasis-suppressing gene product CD82 and its analogue CD9, with concurrent glycosylation.

Metastasis-suppressing gene product CD82 and its analogue CD9 are considered to suppress the malignancy of various human cancers, although the rationale for this effect is unknown. The present study addresses phenotypic changes in Chinese hamster ovary mutant cell line ldlD deficient in UDP-Glc 4-epimerase and expressing CD82 or CD9 by cDNA transfection. Only CD82- or CD9-expressing cells grown in Gal-supplemented medium showed reduced motility and massive cell death, which are characteristic of apoptosis, after a latent period. Under this condition, endogenous GM3 synthesis was observed as a common factor, and N-glycosylation occurred at a high level in CD82 and to a lesser extent in CD9. Thus, the malignancy-suppressing effect of CD82 or CD9 is based partially on cell motility inhibition and apoptosis induction promoted by concurrent GM3 synthesis and N-glycosylation.

Animals↗
PubMed1999

Deletion of A-antigen in a human cancer cell line is associated with reduced promoter activity of CBF/NF-Y binding region, and possibly with enhanced DNA methylation of A transferase promoter.

Employing blood group A- and A+ clones derived from the same parental colonic cancer cell lines, we studied the molecular mechanism of deletion/reduction vs. continuous expression of A antigen in A tumors, a crucial determinant of human tumor malignancy. A- transferase mRNA level in one of the A- clones (A- SW480) was undetectable, while that in A+ SW480 was strongly detectable by semiquantitative RT-PCR. Relatively lower (approximately 1/3) transcript level was detectable in another A- clone (A- HT29) in comparison to A+ HT29 by the same RT-PCR procedure, although none of these tumor cell lines showed detectable level of A transcript by Northern blotting or RNase protection methods. Therefore, subsequent studies were performed employing A- vs. A+ SW480 clones. Deletion of A transcript in A- cells was not due to gene deletion, since Southern blot analysis showed equal presence of genomic DNA regardless of A- vs. A+ (SW480 or HT29) or B+ (KATOIII) tumor cells. Two transcriptional control mechanisms leading to differences of A expression in SW480 cells are indicated. i. Luciferase assay in A- and A+ SW480 cells showed that promoter activities of segments of 5' flanking sequence of ABO gene reflected transcript levels in these cell lines. The enhancing activity of a 43 bp tandem repeat unit located between -3899 to -3618 was reduced in A- compared to A+ cells. ii. Distinct differences in the pattern of CpG dinucleotide methylation were found in A- vs. A+ cells. Therefore, the methylation process of A promoter DNA may be another important factor controlling A activity in SW480 tumor cells. Since proliferation and motility of tumor cells are associated closely with A expression, transcription control mechanism for expression of A transferase as described above may be of crucial importance in defining human tumor malignancy.

ABO Blood-Group System↗
PubMed1999

The relationship between lifestyle, social characteristics and obesity in 3-year-old Japanese children.

It has been observed that obese children receive genetic and environmental effects that are associated with them being overweight. With regard to the latter, lifestyles such as eating habits and physical activity have been focused on. In the present study, the social characteristics which would dominate their lifestyles were investigated as background variables. For this purpose, 9668 Japanese children aged three years who were all born in Toyama prefecture, Japan, in 1998, served as birth cohort subjects. For the comparison between obese (Kaup Index; mass in kg/(height in m)2 > or = 18) and nonobese (Kaup index < 18) children, irregular snack intake, physical inactivity and reduced sleeping hours were chosen as statistically significant obesity-related lifestyle indicators for the children. For social characteristics, family construction (expanded family with grandparents/nonexpanded family), main caregiver (mother/other), attending a nursery school (yes/no) and mother's employment (full-time worker/other) were chosen. These were significantly associated with the obesity-related lifestyles mentioned above using multiple logistic regression analysis adjusted for other variables of social characteristics as well as for gender and birth month (July-December/January-June). The two greatest population-attributable risk percentages were observed for mother as main caregiver (-36.5%) and attending a nursery school (-28.9%) for irregular snack intake. Therefore, these two social characteristics substantially reduced the number of children with irregular snack intake. On the other hand, the two social characteristics were reversed in children with reduced sleeping hours (population-attributable risk percentage of mother as main caregiver: 15.4%; attending a nursery school: 17%). In contrast with favourable effects on snack intake these social characteristics showed an adverse influence on the sleeping habits of children.

Child, Preschool↗
PubMed1999

Obesity, weight gain and risk of colon adenomas in Japanese men.

Obesity has been related to increased risk of colon cancer or adenomas, but the epidemiologic findings are not entirely consistent. We examined the relation of not only body mass index (BMI) but also waist-to-hip ratio (WHR) and weight gain to colon adenoma risk in men who received a preretirement health examination at the Japan Self Defense Forces (SDF) Fukuoka and Kumamoto Hospitals during the period from 1995 to 1996. In the series of 803 men at age 47-55 years, 189 cases of colon adenomas and 226 controls with normal total colonoscopy were identified. Weight at 10 years before was ascertained by referring to the recorded data. After allowance for hospital, rank in the SDF, smoking and alcohol use, weight gain over the past 10 years was significantly associated with increased risk of colon adenomas (odds ratio for > or = 6 kg versus < or =-2 kg = 2.2; 95% confidence interval 1.0-4.8). High BMI and high WHR were each associated with increased risk, but only WHR was related to the risk independently of weight gain. In particular, weight gain accompanied with a high WHR was associated with a significant increase in the risk. Men with high physical activity tended to have lower risk. Associations with obesity-related variables and physical activity were not materially differential as regards the location and size of adenoma. The findings indicate that weight gain in middle age leading to abdominal obesity increases the risk of colon adenomas, and consequently of colon cancer.

Adenoma↗
PubMed1999

Convertase activity in alveolar surfactant and lamellar bodies in fetal, newborn, and adult rabbits.

Conversion of heavy-aggregate alveolar surfactant (H) to a light-aggregate, nonsurface active form (L) is believed to involve the activity of an enzyme, namely, convertase. This conversion can be reproduced in vitro by the surface-area cycling technique. The purpose of the present study was to use this technique to investigate the developmental aspects of convertase activity in fetal, newborn, and adult rabbits. H was isolated from alveolar lavage from term [31-day gestation (31d)] fetal rabbit pups, 1-, 4-, and 7-day-old newborns, and adults, and the percent conversion to L was determined. To assess lamellar bodies (LB) as a potential source of activity in this species, these structures were isolated from lung tissue of 27-day-gestation (27d) and 31d fetuses, 1-, 4-, and 7-day-old newborns, and adults and were cycled the same as for H. LB contained considerable activity at each developmental stage i.e., approximately 82% of a 27d LB preparation converted to L after 3 h of cycling. In the adult, this value was 78%. Very little conversion of H was obtained from fetal lung (i.e., <20% of the 31d fetal preparation converted to L), but, by postnatal day 4, this value was greatly increased (i.e., >80% conversion) and stayed elevated to adulthood. The activity for each H and LB fraction was temperature and concentration dependent and diminished with storage at 4 degreesC. These data suggest the LB as the source of convertase activity in the rabbit and demonstrate dramatic developmental changes in this activity after release of the LB contents to the alveoli.

Aging↗
PubMed1999

Biphasic relaxation caused by electrical field stimulation of the mesenteric arteries of rats.

Electrical field stimulation (EFS) caused biphasic relaxation, first transient and then sustained, of rat mesenteric arteries precontracted by prostaglandin (PG) F2alpha. The transient relaxation was reduced about 45%, and the sustained relaxation was not observed after endothelium denudation of the arteries. N(omega)-Nitro-L-arginine (L-NOARG) inhibited the biphasic relaxation induced by EFS. At 1 - 100 microM, L-NOARG inhibited the transient relaxation more than the sustained relaxation. Methylene blue inhibited the biphasic relaxation and at 100 microM, L-NOARG abolished the transient relaxation. These results suggest that the transient relaxation mainly involves nitric oxide (NO), whereas the sustained relaxation involves both NO and some other factor(s).

Animals↗
PubMed1998

Separation of "glycosphingolipid signaling domain" from caveolin-containing membrane fraction in mouse melanoma B16 cells and its role in cell adhesion coupled with signaling.

Two membrane subfractions, one enriched in GM3 ganglioside and the other containing caveolin, were separated from low density detergent-insoluble membrane fraction prepared by sucrose density gradient centrifugation of postnuclear fraction of mouse melanoma B16 cells. The GM3-enriched subfraction, separated by anti-GM3 monoclonal antibody DH2, contained sphingomyelin, cholesterol, c-Src, and Rho A but not caveolin. In contrast, the caveolin-containing subfraction, separated by anti-caveolin antibody, contained neither GM3, c-Src, nor Rho A but did contain glucosylceramide, Ras, a very small quantity of sphingomyelin, and a very large quantity of cholesterol. The GM3/c-Src-enriched membrane subfraction was characterized by (i) maintenance of GM3-dependent adhesion and (ii) susceptibility to being activated for signal transduction through GM3. 32P-Phosphorylation of c-Src (Mr 60,000) together with two other components (Mr 45,000 and 29,000) was enhanced in the fraction bound to dishes coated with asialo-GM2 (Gg3) or with anti-GM3 monoclonal antibody DH2, detected by incubation with [gamma-32P]ATP at 37 degreesC for 5 min. GM3-dependent adhesion of B16 cells to Gg3-coated dishes and associated signaling were not reduced or abolished in the presence of either filipin or nystatin, which are cholesterol-binding reagents known to abolish caveolae structure and function. B16 melanoma cells incubated with filipin (0.16-0.3 micrograms/ml) or with nystatin (25 micrograms/ml) for 30 min showed depletion of cholesterol in detergent-insoluble membrane fraction but were still capable of binding to Gg3-coated plate and capable of the associated signaling. Thus, the GM3-enriched subfraction, involved in cell adhesion and capable of sending signals through GM3, represents a membrane domain distinguishable from caveolin-containing subfraction or caveolae. This microdomain is hereby termed the "glycosphingolipid signaling domain" or "glycosignaling domain".

Animals↗
PubMed1998

Histo-blood group A/B antigen deletion/reduction vs. continuous expression in human tumor cells as correlated with their malignancy.

Deletion or reduction of histo-blood group A or B antigen in tumors of A or B individuals is clearly correlated with the degree of malignancy and metastatic potential in many types of human cancer. Haptotactic motility of A+H- or B+H- colonic or gastric tumor cell lines produced by transfection of A or B gene was significantly lower than that of parental A-H+ or B-H+ cells. This is ascribable to reduced function of alpha3 or alpha6/beta1 integrin receptor as we have recently shown. However, phenotypic changes resulting from gene transfection may not reflect physiological states associated with deletion or reduction vs. continuous expression of A or B antigen in tumors. We now describe the separation and phenotype characterization of A- cells from A+ tumor cell lines derived originally from colonic tumors of patients with histo-blood group A. A+ and A- populations were detected in originally A+ tumor cell lines SW480 and HT29. A- separated from A+ populations isolated from SW480 and HT29 were characterized by greatly enhanced haptotactic motility associated with reduced or deleted A expression at alpha3, alpha6, and beta1 integrin receptors which control cell motility. Nevertheless, expression of integrin receptors at the surface of A populations is the same as that for A+ populations for both SW480 and HT29 cells. Thus, A vs. H glycosylation in integrin receptors may alter their haptotactic function. Cell proliferation as reflected by 3H-thymidine incorporation was also reduced significantly in A+ as compared to A- populations. Our findings indicate that the degree of haptotactic motility and proliferation of colonic tumor cells are physiologically associated with the deletion or reduction vs. continuous expression of the histo-blood group A antigen.

ABO Blood-Group System↗