A fibrinogen-clotting enzyme (bothrombin) was purified from the venom of Bothrops jararaca. Bothrombin showed M(r) values of 33,000 under nonreducing and 35,000 under reducing conditions on SDS polyacrylamide gel electrophoresis and specific fibrinogen-clotting activity equivalent to 814-904 NIH alpha-thrombin units/mg. Diisopropyl fluorophosphate totally abolished its activity, but hirudin, a specific alpha-thrombin inhibitor, had negligible effect on bothrombin activity. Unlike alpha-thrombin, bothrombin split off fibrinopeptide A without releasing fibrinopeptide B. Bothrombin activated blood coagulation factor VIII, but its activity was about 950 times less than that of alpha-thrombin. Bothrombin did not induce aggregation or serotonin release of washed normal platelets by itself, but did aggregate platelets in the presence of exogenous fibrinogen. This latter activity was completely inhibited by either anti-glycoprotein (GP) IIb/IIIa monoclonal antibody (which blocks fibrinogen binding to GP IIb/IIIa) or anti-GP Ib monoclonal antibody (which specifically inhibits alpha-thrombin binding to GP Ib). Prostaglandin E1 (1 microM) and EDTA (10 mM) also abolished platelet aggregation without affecting clotting activity. Washed platelets from a patient with Bernard-Soulier syndrome did not respond to bothrombin even in the presence of exogenous fibrinogen, suggesting that the initial binding of bothrombin on platelets is GP Ib, but not a recently cloned thrombin receptor. The complete amino acid sequence of bothrombin was determined by analysis of (S)-pyridylethylated protein and peptides generated by digestion with cyanogen bromide and Achromobacter protease I, respectively. Bothrombin is composed of 232 amino acid residues and contains three Asn-linked oligosaccharide chains.(ABSTRACT TRUNCATED AT 250 WORDS)

SummaryA platelet glycoprotein lb-binding protein (GPIb-BP) was isolated from the snake venom of Bothrops jararaca. Jararaca GPIb-BP showed a single band with Mr of 30,000, and two distinct bands with Mr. of 17,000/13,000 under non-reducing and reducing conditions, respectively, on SDS-polyacrylamide gel electrophoresis. Jararaca GPIb-BP itself induced neither platelet aggregation nor serotonin release from platelets, but specifically bound to GPIb (40,629 ± 2,521 molecules per normal platelet, with Kd 39.1 ± 2.4 nM at saturation). The purified venom protein completely inhibited ristocetin- or botrocetin-induccd von Willebrand factor (vWF) binding, and blocked the bovine vWF binding to GPIb, with IC50 values ranging from 28 to 42 nM, without affecting the platelet aggregation induced by ADP or α-thrombin. 1251-jararaca GPIb-BP binding to GPIb was not altered by the presence of human α-thrombin. Jararaca GPIb-BP at a final concentration of 104 nM totally abolished vWF-dependent shear- induced platelet aggregation (SIPA) at a high shear stress, but had no effect on SIPA at a low shear stress. Reduced and S-carboxyamidomethylated jararaca GPIb-BP lost its inhibitory activity on SIPA. The NH2-terminal amino acid sequences of the subunits revealed a high degree of homology with those of several Ca2+-dependent lectins, especially to those of two functionally opposite venom proteins, botrocetin (a vWF-modulator) and alboaggregin-B (a GPIb- modulator).

SummaryA von Willebrand factor (vWF)-binding and -cleaving metalloproteinase, termed “kaouthiagin”, was purified from the venom of cobra snake Naja kaouthia. Kaouthiagin is a monomer with a molecular mass of about 46 kDa and 51 kDa under non-reducing and reducing conditions, respectively, and the N-terminal amino acid sequence is homologous to high molecular mass snake venom metalloproteinases. Kaouthiagin bound to vWF in a divalent ion-independent manner, but the reduced kaouthiagin failed to interact with vWF, suggesting that the protein conformation maintained by intrachaindisulfide linkages of the molecule is essential for the binding to vWF. Neither botrocetin nor bitiscetin, vWF-binding modulators from another snake venom, interfered with the binding between kaouthiagin and vWF, but a monoclonal antibody VW92-3 specific to the N-terminal region of vWF (residues 1-910) inhibited the binding. Without affecting platelet GPIb/IX and GPIIb/IIIa, kaouthiagin specifically cleaved vWF between residues Pro-708 and Asp-709 in a divalent ion-dependent manner to diminish the multimeric structure of vWF in plasma, resulting in the loss of ristocetin-induced platelet aggregability and the collagen-binding activity of vWF. These results indicate that kaouthiagin is a unique metalloproteinase which specifically binds to and cleaves vWF at a specific site and that it will be a useful tool for functional dissection of vWF.

We have determined the nucleotide sequence of the coding region in the last two coding exons of ABO genes from two c/k-AB individuals (genotype cis- AB/O) with no consanguinity. In this region, ris-AB alleles from these 2 individuals were identical to one another while different from the A^1 allele by two nucleotide substitutions. Both of these nucleotide substitutions result in amino acid substitutions. The first substitution is identical to the one previously found in the A^2 allele. The other substitution is found at the fourth position of the four amino acid substitutions which discriminate A^1 and B transferases.

We recently identified ABO(H) blood group structures in Asn-linked sugar chains of human von Willebrand factor (vWF) purified from factor VIII concentrates (J Biol Chem 267:8723, 1992). We surveyed plasma glycoproteins carrying ABO(H) blood group antigens by Western blotting analysis and sandwich enzyme-linked immunosorbent assay using blood group-specific monoclonal antibodies (MoAbs) and a lectin. Two major plasma proteins showing apparent molecular weight of about 180 Kd and 270 Kd by sodium dodecyl sulfate polyacrylamide gel electrophoresis reacted with blood group-specific MoAbs and Ulex europaeus lectin I in accordance with donor blood group. Direct sequence analysis of the protein bands showed their identity with the N-terminal sequences of alpha 2-macroglobulin (alpha 2M) and vWF, respectively. The two bands also reacted with anti-alpha 2M and anti-vWF antibodies. The alpha 2M and vWF prepared from plasma by immunoprecipitation showed the appropriate blood group antigenicity. After incubation with endoglycosidase F, both alpha 2M and vWF lost almost all reactivity with anti-blood group reagents. About 90% of plasma vWF, but only approximately 10% of alpha 2M, was immunoprecipitated with anti-blood group antibody. These results indicate that at least two plasma glycoproteins, vWF and alpha 2M, possess Asn-linked ABO(H) blood group antigens in normal individuals with corresponding ABO phenotype. Therefore, ABO(H) blood group antigens in plasma glycoproteins should be considered during preparation of plasma materials for therapeutic use.

We previously identified a human leukocyte antigen (HLA)-A24-restricted antigenic peptide, survivin-2B80–88, a member of the inhibitor of apoptosis protein family, recognized by CD8+cytotoxic T lymphocytes (CTL). In a phase I clinical trial of survivin-2B80-88 vaccination for metastatic urothelial cancer (MUC), we achieved clinical and immunological responses with safety. Moreover, our previous study indicated that interferon alpha (IFNα) enhanced the effects of the vaccine for colorectal cancer. Therefore, we started a new phase I clinical trial of survivin-2B80–88 vaccination with IFNα for MUC patients. Twenty-one patients were enrolled and no severe adverse event was observed. HLA-A24/survivin-2B80–88 tetramer analysis and ELISPOT assay revealed a significant increase in the frequency of the peptide-specific CTLs after vaccination in nine patients. Six patients had stable disease. The effects of IFNα on the vaccination were unclear for MUC. Throughout two trials, 30 MUO patients received survivin-2B80–88 vaccination. Patients receiving the vaccination had significantly better overall survival than a comparable control group of MUO patients without vaccination (P = 0.0009). Survivin-2B80–88 vaccination may be a promising therapy for selected patients with MUC refractory to standard chemotherapy. This trial was registered with UMIN00005859.

Prostate cancer cells include a small population of cancer stem-like cells (CSCs) ⁄ cancer-initiating cells (CICs) that have roles in initiation and progression of the cancer. Recently, we isolated prostate CSCs ⁄ CICs as aldehyde dehydrogenase 1-highh (ALDH1 high ) cells using the ALDEFLUOR assay; however, the molecular mechanisms of prostate CSCs ⁄ CICs are still elusive. Prostate CSCs ⁄ CICs were isolated as ALDH1 high cells using the ALDEFLUOR assay, and the gene expression profiles were analyzed using a cDNA microarray and RT-PCR. We found that prostate CSCs ⁄ CICs expressed higher levels of growth factors including hepatocyte growth factor (HGF). Hepatocyte growth factor protein expression was confirmed by enzyme linked immunosorbent assay and Western blotting. On the other hand, c-MET HGF receptor was expressed in both CSCs ⁄ CICs and non-CSCs ⁄ CICs at similar levels. Hepatocyte growth factor and the supernatant of myofibloblasts derived from the prostate augmented prostasphere formation in vitro, and prostasphere formation was inhibited by an anti-HGF antibody. Furthermore, c-MET gene knockdown by siRNA inhibited the prostasphere-forming ability in vitro and tumor-initiating ability in vivo. Taken together, the results indicate that HGF secreted by prostate CSCs ⁄ CICs and prostate myofibroblasts has a role in the maintenance of prostate CSCs ⁄ CICs in an autocrine and paracrine fashion. (Cancer Sci 2013; 104: 431-436)

Aldehyde dehydrogenase 1 (ALDH1) and sex determining region-Y-related high mobility group box 2 (SOX2) have been identified as putative cancer stem-like cell/tumor-initiating cell markers in various cancer tissues. The aim of this study was to elucidate the prognostic impact of these putative cancer stem-like cell/tumorinitiating cell markers in upper urinary tract urothelial cell carcinoma. Immunohistochemical staining for ALDH1 and SOX2 was carried out on archival specimens from 125 patients with upper urinary tract urothelial cell carcinoma who underwent radical nephroureterectomy. The prognostic value of ALDH1 and SOX2 expression and other clinicopathological features was evaluated. On univariate analysis, tumor grade, pathological T stage, pathological N stage, lymphovascular invasion, ALDH1 expression and SOX2 expression were associated with a poor prognosis. On multivariate analysis, the independent factors of prognosis were tumor grade (P ¼ 0.014), pathological N stage (P ¼ 0.005) and ALDH1 expression (P ¼ 0.002). In subgroup analysis, those subgroups with no positive, one positive or two positive results in immunohistochemistry for ALDH1 and SOX2 expression had estimated 5-year cancer-specific survival rates of 80%, 49% and 22%, respectively (Po0.001). Neither ALDH1 nor SOX2 expression correlated with intravesical recurrence after radical nephroureterectomy. These findings suggest that cancer stem-like cells/tumor-initiating cells are linked to more aggressive behavior of upper urinary tract urothelial cell carcinoma, supporting the current cancer stem cell hypothesis. Thus, therapeutic targeting of cancer stem-like cells/tumor-initiating cells in upper urinary tract urothelial cell carcinoma is a future possibility.