Takahiko Sakuma

Purification and cDNA cloning of porcine brain GDP-L-Fuc : N-acetyl-beta-D-glucosaminide alpha1->6fucosyltransferase

GDP-L-Fuc:N-acetyl-β-D-glucosaminide α1→6fucosyltransferase (α1-6FucT; EC 2.4.1.68), which catalyzes the transfer of fucose from GDP-Fuc to N-linked type complex glycopeptides, was purified from a Triton X-100 extract of porcine brain microsomes. The purification procedures included sequential affinity chromatographies on GlcNAcβ1-2Manα1-6(GlcNAcβ1-2Manα1-2)Manβ1-4GlcNAcβ1-4GlcNAc-Asn-Sepharose 4B and synthetic GDP-hexanolamine-Sepharose 4B columns. The enzyme was recovered in a 12% final yield with a 440,000-fold increase in specific activity. SDS-polyacrylamide gel electrophoresis of the purified enzyme gave a major band corresponding to an apparent molecular mass of 58 kDa. The α1-6FucT has 575 amino acids and no putative N-glycosylation sites. The cDNA was cloned in to pSVK3 and was then transiently transfected into COS-1 cells. α1-6FucT activity was found to be high in the transfected cells, as compared with non- or mock-transfected cells. Northern blotting analyses of rat adult tissues showed that α1-6FucT was highly expressed in brain. No sequence homology was found with other previously cloned fucosyltransferases, but the enzyme appears to be a type II transmembrane protein like the other glycosyltransferases.

Reduced Levels of ATF-2 Predispose Mice to Mammary Tumors

ABSTRACT Transcription factor ATF-2 is a nuclear target of stress-activated protein kinases, such as p38, which are activated by various extracellular stresses, including UV light. Here, we show that ATF-2 plays a critical role in hypoxia- and high-cell-density-induced apoptosis and the development of mammary tumors. Compared to wild-type cells, Atf-2−/− mouse embryonic fibroblasts (MEFs) were more resistant to hypoxia- and anisomycin-induced apoptosis but remained equally susceptible to other stresses, including UV. Atf-2−/− and Atf-2+/− MEFs could not express a group of genes, such as Gadd45α, whose overexpression can induce apoptosis, in response to hypoxia. Atf-2−/− MEFs also had a higher saturation density than wild-type cells and expressed lower levels of Maspin, the breast cancer tumor suppressor, which is also known to enhance cellular sensitivity to apoptotic stimuli. Atf-2−/− MEFs underwent a lower degree of apoptosis at high cell density than wild-type cells. Atf-2+/− mice were highly prone to mammary tumors that expressed reduced levels of Gadd45α and Maspin. The ATF-2 mRNA levels in human breast cancers were lower than those in normal breast tissue. Thus, ATF-2 acts as a tumor susceptibility gene of mammary tumors, at least partly, by activating a group of target genes, including Maspin and Gadd45α.

Bronchial brushing and bronchial biopsy: comparison of diagnostic accuracy and cell typing reliability in lung cancer.

A total of 443 patients with lung cancer underwent brush and forceps biopsy through a fibreoptic bronchoscope. The biopsy was taken from the area of suspected malignancy which had been brushed. Of 443 patients, 400 (90.3%) showed positive results on brushing and 287 (64.8%) on biopsy. A combination of both techniques yielded the highest percentage of positive diagnosis (93.7%). Histologically, there was a high incidence of positive diagnosis for squamous and small cell carcinoma. One hundred and three (83.7%) of 123 specimens obtained by brushing and 75 (81.5%) of 92 specimens obtained by biopsy agreed with the cell type found in the surgical or necropsy specimen. Cell typing accuracy was higher in squamous and in small cell carcinoma in both techniques. As the cell typing accuracy of the two methods is similar, the results obtained by both techniques should be taken into consideration in the management of individual cases of lung cancer.

Identification of Promoter Regions Involved in Cell- and Developmental Stage-Specific Osteopontin Expression in Bone, Kidney, Placenta, and Mammary Gland: An Analysis of Transgenic Mice†

Cell‐specific expression of GFP under the control of different lengths of the osteopontin promoter in transgenic mice identified the positive and negative regulatory regions for respective cell types. The results provide new insights for physiological and pathological expression of the osteopontin gene.

Urine cytology of micropapillary carcinoma of the urinary bladder.

A case of micropapillary carcinoma (MPC) of urinary bladder is presented, in which the urine smear was studied in detail in an attempt to better characterize the cytologic findings of MPC. When the voided urine was examined in low power, cancer cells were scattered in the specimens as compact papillary/spheroidal clusters composed of pleomorphic cancer cells. Solitary carcinoma cells were occasionally observed. High power view of the smear revealed that the papillae/spheroids consisted of high‐grade urothelial carcinoma cells. The cancer cells had pleomorphic nuclei with coarsely granular chromatin and thickened, irregular nuclear membrane, and thick cytoplasm. Histologically, the tumor in the resected bladder appeared as small nests with surrounding hallo both in the luminal surface and in the site of wall involvement. These tightly bound papillary/spheroidal clusters comprised of highly atypical cancer cells were the most specific cytologic finding in the urine of MPC, which were considered as a key diagnostic clue of MPC. The background of the urine smear showed numerous granulocytes and bacilli compatible with cystitis, which is a previously known complication of MPC. Differential diagnoses of MPC from those with pertinent cytologic findings such as conventional UC (including glandular differentiation), and primary/secondary adenocarcinoma of urinary bladder are discussed with a brief review of literature. Diagn. Cytopathol. 2011.

Homologous complement activation on drug-induced apoptotic cells from a human lung adenocarcinoma cell line.

Activation of the alternative pathway of homologous complement (C) was observed in a human lung adenocarcinoma cell line, CADO 43, after the cells had become apoptotic following treatment in vitro with vincristine and predonisolone. Deposition of C3b and C3bi on the serum-treated apoptotic cells was revealed by flow cytometry with anti-C3b and -C3bi-specific antibodies and immunoblotting with anti-C3 antibody immunoprecipitates extracted from solubilized fractions of serum-treated apoptotic cells. Two molecular mechanisms were found to be responsible for this post-apoptotic C-activation. Firstly, all C regulators, decay accelerating factor (DAF), membrane cofactor protein (MCP) and C3b/C4b receptor (CR1), were diminished on the cell surface concomitantly with the apoptotic process. Secondly, unidentified molecules which potentially activate homologous C and accept C3b/C3bi fragments became expressed on the cell surface during the apoptotic process. These findings may explain the mechanism whereby tumor cells are efficiently eliminated through chemotherapy.

Cloning and expression pattern of a novel PEBP2β-binding protein (charged amino acid rich leucine zipper-1 [Crl-1]) in the mouse

PEBP2 beta/Cbf beta is the beta subunit of PEBP2/Cbf, which has been demonstrated to have important biological activities in hematopoiesis and osteogenesis. However, PEBP2 beta is ubiquitously expressed, suggesting that PEBP2 has other additionally important physiological activities. In an effort to elucidate other possible functions for PEBP2, we have isolated a novel gene that encodes a PEBP2 beta-interacting protein from a mouse cDNA library. We have called this gene Crl-1 for charged amino acid rich leucine zipper-1 (Crl-1) because it is rich in charged amino acids and contains a putative leucine zipper region. Expression studies in a 17.5 days post-coitum mouse embryo demonstrated Crl-1 expression mainly in the olfactory bulb and cerebral cortex. Post-natally, Crl-1 expression was additionally observed in the cerebellar cortex with strong expression in the hippocampus. These findings show that this novel PEBP2 beta-interacting protein is expressed mainly in subsets of neuronal cells, suggesting that Crl-1 plays some role in the developing mouse brain.

Diagnostic value of high molecular weight alkaline phosphatase in detection of hepatic metastasis in patients with lung cancer

High molecular weight alkaline phosphatase (HMW‐ALP) was measured in the sera of 126 patients with lung cancer to determine its diagnostic value in the detection of hepatic metastasis. This isoenzyme was found in 21 of 24 patients with hepatic metastasis and in 27 of 102 patients without hepatic metastasis. When 10 U/L was used as a cut‐off value, the sensitivity, specificity, and accuracy of this test were 71%, 89%, and 86%, respectively. From the standpoint of histologic type, this test was most useful in patients with small cell carcinoma. HMW‐ALP was not detected in the sera of 15 controls. It is concluded that HMW‐ALP is a useful marker for hepatic metastasis in patients with lung cancer.

Extensive Ganglioneuromatosis of Gallbladder

A case of extensive ganglioneuromatosis (GN) of gallbladder is presented. A 38-year-old man presented with a hepatic hilar mass (∅ ~ 48 mm) and gall stones. He had undergone total thyroidectomy for medullary thyroid carcinoma 8 years earlier. The hepatic hilus tumor, which had been clinically suspected to be a lymph node metastasis from the medullary thyroid carcinoma, was found to be pheochromocytoma. The gallbladder, resected with a clinical diagnosis of cholelithiasis, showed extensive transmural GN despite a grossly normal appearance. Taking into account the past history, the patient was diagnosed as having multiple endocrine neoplasia 2b (MEN2b)–associated GN of gallbladder and ectopic pheochromocytoma. As GN of gallbladder in MEN2b has been rarely reported, the histological findings are described in detail and a brief review of literature is carried out.

Molecular cause of the severe functional deficiency in osteoclasts by an arginine deletion in the basic domain of Mi transcription factor.

Abstract Severe osteopetrosis was observed in mi/mi mutant mice. However, the bone of VGA9/VGA9 mutant mice, in which Mi gene expression is undetectable, showed normal histology. No osteopetrosis was found in mi/+ mice, but was observed in VGA9/mi mice. Biochemical analysis revealed that the gene product encoded with the mi mutant allele (mi–Mi) has impared DNA binding activity and nuclear translocation ability. Furthermore, inhibitory effects of mi–Mi were shown not only on the DNA binding activity of wild-type Mi, but also on the nuclear translocation ability of Mi, PU.1 and cFOS. The present results suggest the presence of a target gene for Mi that is essential for the proliferation/differentiation of osteoclasts.