Carbohydrate structures of the cell adhesion molecule, contact site A, from Dictyostelium discoideum

AbstractWe determined the carbohydrate structures of contact site A from Dictyostelium discoideum. The carbohydrate moieties of contact site A were released by hydrazinolysis. Fractionation of the deacidified oligosaccharide mixture by Bio-Gel P-4 column chromatography revealed that it was composed of four major oligosaccharides. Their respective structures were determined by sequential exoglycosidase digestion. It is known that contact site A consists of two kinds of carbohydrates, I and II. Taking together the previous and the present results, it was deduced that carbohydrate I comprises N-linked oligosaccharides and carbohydrate II O-linked ones. Furthermore, the relative molar contents of GalNAc and GlcNAc in reducing terminal suggested that contact site A contains 67% of N-linked and 33% of O-linked oligosaccharides

The low expression of miR-451 predicts a worse prognosis in non-small cell lung cancer cases

Purpose miR-451 is a tumor suppressive microRNA with several target genes, including Macrophage migration inhibitory factor (MIF). As little is known about the expression and clinicopathological significance of mir-451 in NSCLC, we performed a clinicopathological study of 370 NSCLC cases to clarify them. Cell biological experiments were also performed on NSCLC cell lines to confirm the tumor-suppressive role of miR-451 and whether or not MIF is targeted by miR-451. Methods We analyzed 370 NSCLC cases for the miR-451 expression by quantitative real-time polymerase chain reaction and the MIF expression by immunohistochemistry. Eighty-four background lung tissue samples were also evaluated for the miR-451 expression. The clinicopathological and genetic factors surveyed were the disease-free survival, smoking status, histological type, disease stage, EGFR gene mutations and ALK rearrangements. In 286 adenocarcinoma cases, the invasive status (adenocarcinoma in situ, minimally invasive adenocarcinoma and invasive adenocarcinoma) was also evaluated. Five NSCLC cell lines (H23, H441, H522, H1703, and H1975) were cultured and evaluated for their miR-451 and MIF expression. The cell lines with lower miR-451 and higher MIF expressions were then selected and transfected with miR-451-mimic to observe its effects on MIF expression, Akt and Erk status, cell proliferation, and cell migration. Results The miR-451 expression was down-regulated in cancer tissues compared with background lung tissues (P<0.0001). Factors such as advanced disease stage, positive pleural invasion and nodal status and being a smoker were significantly correlated with a lower expression of miR-451 (P<0.05 each), while EGFR gene mutations and ALK rearrangements were not. In adenocarcinoma, invasive and minimally invasive adenocarcinoma showed lower expression of miR-451 than adenocarcinoma in situ (P<0.0005, respectively). A survival analysis showed that a lower expression of miR-451 was an independent predictor of a poor prognosis for NSCLC (P<0.05). The MIF expression was inversely correlated with the miR-451 expression. Out of 5 NSCLC cell lines examined, H441 and H1975 showed higher MIF and lower miR-451 expressions. After the transfection of miR-451-mimic, the MIF expression and phosphorylated Akt expression of these cell lines was suppressed, as were cell proliferation and cell migration. Conclusion This clinicopathological study of 370 NSCLC cases and the cell biological studies of NSCLC cell lines clarified the tumor-suppressive role of miR-451 and its prognostic value. We also validated MIF as a target of miR-451 in NSCLC

Association of variations in HLA class II and other loci with susceptibility to EGFR-mutated lung adenocarcinoma

Lung adenocarcinoma driven by somatic EGFR mutations is more prevalent in East Asians (30-50%) than in European/Americans (10-20%). Here we investigate genetic factors underlying the risk of this disease by conducting a genome-wide association study, followed by two validation studies, in 3,173 Japanese patients with EGFR mutation-positive lung adenocarcinoma and 15,158 controls. Four loci, 5p15.33 (TERT), 6p21.3 (BTNL2), 3q28 (TP63) and 17q24.2 (BPTF), previously shown to be strongly associated with overall lung adenocarcinoma risk in East Asians, were re-discovered as loci associated with a higher susceptibility to EGFR mutation-positive lung adenocarcinoma. In addition, two additional loci, HLA class II at 6p21.32 (rs2179920; P =5.1 × 10(-17), per-allele OR=1.36) and 6p21.1 (FOXP4) (rs2495239; P=3.9 × 10(-9), per-allele OR=1.19) were newly identified as loci associated with EGFR mutation-positive lung adenocarcinoma. This study indicates that multiple genetic factors underlie the risk of lung adenocarcinomas with EGFR mutations

粘菌細胞におけるcsAのアンカー領域の性状について

[Synopsis] A cell adhesion molecule, csA, is a glycoprotein with a molecular weight of 80-kDa and is involved in EDTA-resistant cell contact at the aggregation stage of Dictyostelium discoideum. A 31-kDa csA with glycosylphosphatidyl-inositol (GPI) anchor was isolated from a 80-kDa csA by treatment of Achromobacter protease I. Comparison between the 31-kDa csA and the 80-kDa csA on treatment with phosphatidylinositol-specific phospholipase C (PI-PLC) or phospholipase D (PLD) was carried out. The results indicated that the GPI-anchor in the 31-kDa csA was more sensitive to PI-PLC treatment than that in the 80-kDa csA, and that the anchor in both was easily cleaved by PLD treatment. In the presence of 1,10-phenanthroline, a PLD inhibitor, development of Dictyostelium was markedly inhibited, suggesting that PLD is functional in developmental regulation.　 (摘要) 粘菌細胞における接着分子csAは集合期のEDTA-resistant cell contactに関与する分子量8.0万の糖タンパク質である。接着分子80kDacsAのAchromobacterプロテアーゼI処理によりアンカー領域を保持した31kDa csAが単離された。接着分子80kDa csAと31kDa csAのホスファチジルイノシトール特異的なホスホリパーゼCに対する感受性は31kDa csAが80kDa csAより強かった。一方、ホスホリパーゼD処理に対しては80kDa csAも31kDa csAもともに非常に高い感受性を示し、アンカー領域を遊離した。さらに、ホスホリパーゼD阻害剤1,10-フェナントロリン存在下では粘菌細胞の発生は著しく阻害された。このことはホスホリパーゼDが発生過程での調節に重要な役割を担っていることを示唆する

接着活性に対する重金属の効果

[Synopsis] We studied the effects of heavy metal ions on cell contact of Dictyostelium discoideum, EDTA-resistant cell contact, which appears in an aggregation-competent stage after starvation begins. Heavy metal ions were added after starvation began, and their effects on EDTA-resistant cell contact were investigated for the cells at the aggregation-competent stage. As a result, EDTA-resistant cell contact was significantly affected in cells treated with heavy metal ions: Hg^, Cd^, Pb^ and Cu^ of more than 10^M.　 （摘要）　粘菌細胞（Dictyostelium discoideum)の接着様式のひとつであるEDTA-resistant cell contactにおけるEDTAの役割を検討する目的で重金属を用いて、EDTA-resistant cell contact活性を調べた。その結果、10^M以上のHg^、Cd^、Pb^、Cu^によりEDTA-resistant cell contact 活性は効果的に阻害された

Ca^<2+>依存性細胞接着に対する重金属の効果

[Synopsis] The effects of heavy metal ions on the EDTA-sensitive cell contacts, which exist from growthphase stage of Dictyostelium discoideum, was investigated. EDTA-sensitive cell contacts of cells at the growth-phase stage were analyzed in the presence of heavy metal ions. Heavy metal ions Hg^, Cd^ and Cu^ inhibited EDTA-sensitive cell contacts at concentrations higher than 10^M, whereas Pb^ did not show any recognizable effects at the same concentration range. The possible mechanisms of action of these metal ions are discussed. （摘要）　粘菌細胞(Dictyostelium discoideum) )増殖期から存在しているCa^依存性細胞接着(EDTA-sensitive cell contacts)の機構解析を重金属を用いて行った。その結果、10^M以上のHg^、Cd^、Cu^処理においてCa^依存性細胞接着が効果的に阻害された。一方、Pb^処理では阻害効果は認められなかった