Biomedical subjects

Hajime Okita

Publications and source records attributed to Hajime Okita.

At least 19 recordsLinked to original sources

PubMed2008

Ewing sarcoma/primitive neuroectodermal tumor of the kidney in a child.

A 6-year-old female was admitted with abdominal pain and a mass in the right abdomen. Her lactose dehydrogenase level was 1,200 IU/L, and neuron specific enolase was 120 ng/ml. Computed tomography scan confirmed a large right renal mass with necrosis. A right radical nephrectomy was performed. The tumor was completely encapsulated. Based on small round cell histology, strong MIC-2 (CD99) positive tumor cells, and EWS-FLI-1 fusion transcript, Ewing sarcoma/primitive neuroectodermal tumor of the kidney was diagnosed. Induction and follow-up with seven cycles of chemotherapy were given after surgery. She has had no evidence of recurrence 90 months from diagnosis.

Child↗

PubMed2007

Angiotensin II type 1 receptor antagonist as an angiogenic inhibitor in prostate cancer.

BACKGROUND: Angiotensin II (AII) type 1 receptor (AT1R) antagonists are used widely as antihypertensive agents, and long-term AT1R blockade may have a protective effect against cancer. We previously demonstrated that specific AT1R blockade with candesartan, an AT1R antagonist, inhibited vascular endothelial growth factor (VEGF) production and dramatically decreased lung metastasis of renal cancer by inhibiting tumor angiogenesis. This study was then undertaken to investigate the effects of AT1R blockade using candesartan in prostate cancer (PCa). METHODS: We first determined whether hormone-independence is associated with tumor angiogenesis and AT1R expression. Accordingly, we postulated that AT1R blockade may affect angiogenesis in androgen-independent PCa rather than in androgen-dependent PCa, and investigated the effects of AII and candesartan on PCa cell lines and a tumor xenograft model. RESULTS: A human hormone-refractory PCa (HRPC) and C4-2 androgen-independent PCa cell line showed significantly higher expression of VEGF, MVD, and AT1R than did human androgen-dependent PCa and an LNCaP androgen-dependent PCa cell line. In vitro, AII and candesartan did not directly affect the proliferation of LNCaP and C4-2 cells, but candesartan significantly suppressed VEGF production in C4-2 cells. In vivo, candesartan significantly suppressed VEGF expression, serum PSA concentration and tumor growth (1.1 +/- 0.2, 45.0 +/- 17.6 ng/ml, 235.8 +/- 37.4 mm(3)) in C4-2 xenografts in castrated mice, compared with the controls (2.4 +/- 0.6, 376.7 +/- 74.2 ng/ml, 830.8 +/- 147.6 mm(3)). CONCLUSIONS: Candesartan exerted preventive effects on HRPC, rather than on androgen-sensitive PCa, through the inhibition of tumor angiogenesis.

Aged↗

PubMed2006

Association of 11q loss, trisomy 12, and possible 16q loss with loss of imprinting of insulin-like growth factor-II in Wilms tumor.

We evaluated the WT1 and IGF2 status and performed chromosome and/or comparative genomic hybridization analysis in 43 tumor samples from patients with Wilms tumor. On this basis, we classified them into 4 groups: WT1 abnormality, loss of heterozygosity (LOH) of IGF2, loss of imprinting (LOI) of IGF2, and retention of imprinting (ROI) of IGF2, which were seen in 12%, 30%, 16%, and 42% of the tumors, respectively. Patients in the LOI group were older than those in other groups (P < 0.01), and tumors in the WT1 group had fewer cytogenetic changes than did those in the other groups (P < 0.01). It was found that 11q- and +12 were more frequent in the LOI group than in the WT1+LOH+ROI group (P < 0.01 and P < 0.01). There was no difference in the incidence of 16q- between the LOI group and the other groups; however, when we excluded 16 tumors with LOH on 11p15, 16q- tended to be more frequent in the LOI group than in the WT1+ROI group (P = 0.06). The association of 11q- or +12 with LOI of IGF2 found in the present study suggests that many tumors with no WT1 abnormalities need overexpression of IGF2 together with biallelic inactivation of the tumor-suppressor gene on 11q and/or overexpression of growth-promoting genes on chromosome 12. The 11q gene may code for one of the proteins that constitute a CTCF insulator complex, and its mutation, deletion, or haploinsufficiency may cause insulator abnormalities that might lead to LOI of IGF2.

Child↗

PubMed2006

Involvement of insulin-like growth factor-I and insulin-like growth factor binding proteins in pro-B-cell development.

OBJECTIVE: Insulin-like growth factor (IGF)-binding proteins (IGFBPs) are a family of proteins thought to modulate IGF function. By employing an in vitro culture system of human hematopoietic stem cells cocultured with murine bone marrow stromal cells, we examined the effects of IGF-I and IGFBPs on early B-cell development. MATERIALS AND METHODS: Human CD34(+) bone marrow cells were cocultured with murine stromal MS-5 cells for 4 weeks, and pro-B-cell number was analyzed by flow cytometry. After administration of reagents that are supposed to modulate IGF-I or IGFBP function to the culture, the effect on pro-B-cell development was examined. RESULTS: After cultivation for 4 weeks, effective induction of pro-B-cell proliferation was observed. Experiments using several distinct factors, all of which neutralize IGF-I function, revealed that impairment of IGF-I function results in a significant reduction in pro-B-cell development from CD34(+) cells. In addition, when the effect of recombinant proteins of IGFBPs and antibodies against IGFBPs were tested, IGFBP-3 was found to inhibit pro-B-cell development, while IGFBP-6 was required for pro-B-cell development. CONCLUSIONS: IGF-I is essential for development of bone marrow CD34(+) cells into pro-B cells. Moreover, IGFBPs are likely involved in regulation of pro-B-cell development.

Animals↗

PubMed2006

Desmoplastic small cell tumor of soft tissue: molecular variant of EWS-WT1 chimeric fusion.

A 7-year-old girl was hospitalized because of a tumorous mass in her left periorbital region. The tumor was removed by local excision. The soft-part tumor recurred in the parotid gland region 4 months later, and a second recurrence was noted on the left side of the neck 3 years and 3 months thereafter. The patient had not received chemotherapy or local irradiation. Histological and immunohistochemical examinations of the recurrent masses revealed morphological characteristics of small cell proliferation with desmoplastic stroma that were similar to those of the initial tumor. The cellular components showed immunoreactivity for desmin, cytokeratin, vimentin, and epithelial membrane antigen in part, but the cells were negative for myogenin, CD99, and neuron-specific enolase. These findings suggested a diagnosis of desmoplastic small cell tumor, despite its extra-abdominal location. The histological diagnosis was confirmed by reverse transcriptase polymerase chain reaction, which demonstrated an EWS-WT1 chimeric fusion gene. An in-frame fusion of EWS exon 9 and WT1 exon 8 was subsequently identified by cloning and sequencing. The chimeric fusion gene might be related to the tissue-specific phenotype of desmoplastic small cell tumors, although further investigation of this speculation is necessary.

Child↗

PubMed2005

Laminin binding protein, 34/67 laminin receptor, carries stage-specific embryonic antigen-4 epitope defined by monoclonal antibody Raft.2.

We previously produced monoclonal antibodies against the detergent-insoluble microdomain, i.e., the raft microdomain, of the human renal cancer cell line ACHN. Raft.2, one of these monoclonal antibodies, recognizes sialosyl globopentaosylceramide, which has the stage-specific embryonic antigen (SSEA)-4 epitope. Although the mouse embryonal carcinoma (EC) cell line F9 does not express SSEA-4, some F9 cells stained with Raft.2. Western analysis and matrix-assisted laser desorption ionization-time of flight mass spectrometry identified the Raft.2 binding molecule as laminin binding protein (LBP), i.e., 34/67 laminin receptor. Weak acid treatment or digestion with Clostridium perfringens sialidase reduced Raft.2 binding to LBP on nitrocellulose sheets and [(14)C]galactose was incorporated into LBP, indicating LBP to have a sialylated carbohydrate moiety. Subcellular localization analysis by sucrose density-gradient centrifugation and examination by confocal microscopy revealed LBP to be localized on the outer surface of the plasma membrane. An SSEA-4-positive human EC cell line, NCR-G3 cells, also expressed Raft.2-binding LBP.

Animals↗

PubMed2005

Dietary bioflavonoids induce apoptosis in human leukemia cells.

Dietary bioflavonoids are secondary metabolites of plants that are known to have a variety of bio-effects, including anti-cancer activity. In this study, we examined the effects of flavonoids on the growth of human leukemia cells and found that certain flavonoids induce apoptosis in a variety of human leukemia cells. The apoptosis induced by bioflavonoids was dose-dependent and was accompanied by a disruption of the mitochondrial transmembrane potential and the activation of caspase. Our data suggests that dietary bioflavonoids may be useful chemotherapeutic reagents for leukemia patients.

Annexin A5↗

PubMed2005

Clinical and pathologic significance of activation of signal transducer and activator of transcription 3 in prostate cancer.

OBJECTIVES: To evaluate the association of signal transducer and activator of transcription 3 (STAT3) with the invasiveness and aggressiveness of localized prostate cancer. METHODS: Paraffin-embedded specimens from 92 patients with clinically localized prostate cancer who underwent radical prostatectomy without neoadjuvant treatment were analyzed by immunohistochemistry using two antibodies: anti-phospho-specific STAT3 (p-STAT3) antibody, which recognized only activated STAT3, and anti-total STAT3 antibody, which recognized both activated and inactivated STAT3. The patients were separated into one of four groups according to the percentage of the cells with positive nuclear staining using a 0 to 3+ scoring system. The associations between the immunostaining and invasiveness and aggressiveness of clinically localized prostate cancer were analyzed. RESULTS: Pathologically, 66 patients (71.7%) had organ-confined disease. Of the 92 tumors examined, 8, 20, 23, and 41 showed staining patterns for p-STAT3 of 0, 1+, 2+, and 3+, respectively. In addition, 0, 3, 2, and 87 tumors showed staining patterns for STAT3 of 0, 1+, 2+, and 3+, respectively. The staining patterns for p-STAT3 correlated significantly with pathologic stage, Gleason score, and extracapsular extension. No significant correlation was found between p-STAT3 immunostaining and microvascular invasion, perineural invasion, or seminal vesicle invasion. Patients with 3+ immunostaining of p-STAT3 had a significantly greater biochemical prostate-specific antigen failure rate than those with 2+ or less immunostaining. CONCLUSIONS: Increased p-STAT3 immunoreactivity showed a highly invasive and aggressive potential in patients with localized prostate cancer treated with radical prostatectomy. This suggests that STAT3 signaling contributes to the invasiveness and aggressiveness of prostate cancer.

Aged↗

PubMed2005

The maturation of myeloma cells correlates with sensitivity to chemotherapeutic agents.

We analyzed both morphologic and phenotypic findings of myeloma cells before and after chemotherapy in 21 patients with multiple myeloma. The morphologic analysis was based on the Greipp classification, and phenotypic analysis was performed by 3-color flow cytometry using the CD38 plasma gating method (Marrow plasma 38). Results with flow cytometry using a combination of MPC1, CD49e, and CD45 supported the morphologic findings for the myeloma cells. Treatment with 3 or 4 cycles of VAD (vincristine, doxorubicin, and dexamethasone) therapy was effective in reducing the total numbers of myeloma cells, but the proportion of immature myeloma cells increased after this treatment. However, the immature myeloma cells were reduced by high-dose melphalan (HD-Mel) therapy followed by autologous stem cell transplantation (ASCT). High-dose cyclophosphamide treatment for stem cell harvesting did not show an effect on the residual immature myeloma cells after VAD treatment. In addition, thalidomide was not effective in reducing the numbers of immature myeloma cells. These results suggest that VAD (3 or 4 cycles) therapy plus HD-Mel followed by ASCT is a reasonable treatment for multiple myeloma and that Marrow plasma 38 analysis is a useful method for monitoring the response of multiple myeloma to chemotherapy.

ADP-ribosyl Cyclase↗

PubMed2004

Shiga toxin binding to globotriaosyl ceramide induces intracellular signals that mediate cytoskeleton remodeling in human renal carcinoma-derived cells.

Shiga toxin is a bacterial toxin consisting of A and B subunits. Generally, the essential cytotoxicity of the toxin is thought to be mediated by the A subunit, which possesses RNA cleavage activity and thus induces protein synthesis inhibition. We previously reported, however, that the binding of the Shiga toxin 1-B subunit to globotriaosyl ceramide, a functional receptor for Shiga toxin, induces intracellular signals in a manner that is dependent on glycolipid-enriched membrane domains, or lipid rafts. Although the precise role of this signaling mechanism is not known, here we report that Shiga-toxin-mediated intracellular signals induce cytoskeleton remodeling in ACHN cells derived from renal tubular epithelial carcinoma. Using confocal laser scanning microscopy, we observed that Shiga toxin 1-B treatment induces morphological changes in ACHN cells in a time-dependent manner. In addition, the morphological changes were accompanied by the redistribution of a number of proteins, including actin, ezrin, CD44, vimentin, cytokeratin, paxillin, FAK, and alpha- and gamma-tubulins, all of which are involved in cytoskeletal organization. The transient phosphorylation of ezrin and paxillin was also observed during the course of protein redistribution. Experiments using inhibitors for a variety of kinases suggested the involvement of lipid rafts, Src family protein kinase, PI 3-kinase, and RHO-associated kinase in Shiga toxin 1-B-induced ezrin phosphorylation. Shiga toxin 1-B-induced cytoskeletal remodeling should provide an in vitro model that can be used to increase our understanding of the pathogenesis of Shiga-toxin-mediated cell injury and the role of lipid-raft-mediated cell signaling in cytoskeletal remodeling.

Actins↗

PubMed2004

Diagnostic importance of CD179a/b as markers of precursor B-cell lymphoblastic lymphoma.

Surrogate light chains consisting of VpreB (CD179a) and lambda5 (CD179b) are expressed in precursor B cells lacking a complete form of immunoglobulin and are thought to act as substitutes for conventional light chains. Upon differentiation to immature and mature B cells, CD179a/b disappear and are replaced with conventional light chains. Thus, these molecules may be useful as essential markers of precursor B cells. To examine the expression of the surrogate light-chain components CD179a and CD179b in precursor B-cell lymphoblastic lymphoma, we analyzed tissue sections using immunohistochemistry techniques. Among a number of monoclonal antibodies for the surrogate light chains, VpreB8 and SL11 were found to detect CD179a and CD179b, respectively, in acetone-fixed fresh frozen sections. Moreover, we also observed VpreB8 staining in formalin-fixed, paraffin-embedded sections. Using these antibodies, we found that CD179a/b were specifically expressed in precursor B-cell lymphoblastic lymphomas, but not in mature B-cell lymphomas in childhood. Furthermore, other pediatric tumors that must be included in a differential diagnosis of precursor B-cell lymphoblastic lymphoma, including precursor T-cell lymphoblastic lymphoma, extramedullary myeloid tumors, and Ewing sarcoma, were also negative for both CD179a and CD179b. Our data indicate that CD179a and CD179b may be important markers for the immunophenotypic diagnosis of precursor B-cell lymphoblastic lymphomas.

Adolescent↗

PubMed2004

Development of novel monoclonal antibody 4G8 against swine leukocyte antigen class I alpha chain.

A mouse monoclonal antibody (MAb) was generated against swine leukocyte antigen (SLA) class I alpha chain. A newly developed series of MAb clones that react with pan leukocytes were selected and tested by immuno-histochemistry using SLA class I alpha chain expressing Cos-7 cells. Among them, MAb 4G8 was characterized by the following features: (1) 4G8 reacted with Cos-7 cells transfected with SLA class I alpha chain from the d haplotype, (2) 4G8 recognized epitopes that were different from those of commercially available anti-SLA class I MAbs 74-11-10 and PT85A, and (3) 4G8 could be used to immunostain frozen sections of thymus, spleen, lymph node, kidney, and liver tissues with good results.

Animals↗

PubMed2004

Characterization of a shiga-toxin 1-resistant stock of vero cells.

Shiga toxins (Stxs, also referred to as verotoxins) were first described as a novel cytotoxic activity against Vero cells. In this study, we report the characterization of an Stx1-resistant (R-) stock of Vero cells. (1) When the susceptibility of R-Vero cells to Stx1 cytotoxicity was compared to that of Stx1-sensitive (S-) Vero cells by methylthiazolyldiphenyl-tetrazolium bromide (MTT) assay, cell viability after 48-hr exposure to 10 pg/ml of Stx1 was greater than 80% and less than 15%, respectively. (2) Although both a binding assay of fluorescence-labeled Stx1 and lipid analysis indicated considerable expression of Gb3Cer, a functional receptor for Stxs, in both Vero cells, anti-Gb3Cer monoclonal antibodies capable of binding to S-Vero cells failed to effectively label R-Vero cells, suggesting a conformational difference in the Gb3Cer expressed on R-Vero cells. (3) The lipid analysis also showed that the R-Vero cells contained significant amounts of Gb4Cer. In addition, introduction of exogenous Gb4Cer into S-Vero cells slightly inhibited Stx1 cytotoxicity, suggesting some correlation between glycosphingolipid composition and Stx1 resistance. (4) Both butyrate treatment and serum depression eliminated the Stx1 resistance of R-Vero cells. (5) The results of the analysis by confocal microscopy suggest a difference in intracellular transport of Stx1 between R-Vero and S-Vero cells. Further study of R-Vero cells may provide a model of Stx1 resistance via distinct intracellular transport of Stx1.

Animals↗

PubMed2004

Deficiency of BLNK hampers PLC-gamma2 phosphorylation and Ca2+ influx induced by the pre-B-cell receptor in human pre-B cells.

B-cell linker protein (BLNK) is a component of the B-cell receptor (BCR) as well as of the pre-BCR signalling pathway, and BLNK(-/-) mice have a block in B lymphopoiesis at the pro-B/pre-B cell stage. A recent report described the complete loss or drastic reduction of BLNK expression in approximately 50% of human childhood pre-B acute lymphoblastic leukaemias (ALL), therefore we investigated BLNK expression in human pre-B ALL cell lines. One of the four cell lines tested, HPB-NULL cells, was found to lack BLNK expression, and we used these human pre-B ALL cell lines that express and do not express BLNK to investigate the intracellular signalling events following pre-BCR cross-linking. When pre-BCR was cross-linked with anti-micro heavy-chain antibodies, significant phosphorylation of intracellular molecules, including Syk, Shc, ERK MAP kinase, and AKT, and an activation of Ras were observed without regard to deficiency of BLNK expression, suggesting that BLNK is not required for pre-BCR-mediated activation of MAP kinase and phosphatidyl-inositol 3 (PI3) kinase signalling. By contrast, phospholipase C-gamma2 (PLC-gamma2) phosphorylation and an increase in intracellular Ca(2+) level mediated by pre-BCR cross-linking were observed only in the BLNK-expressing cells, indicating that BLNK is essential for PLC-gamma2-induced Ca(2+) influx. Human pre-B cell lines expressing and not expressing BLNK should provide an in vitro model for investigation of the role of BLNK in the pre-BCR-mediated signalling mechanism.

Adaptor Proteins, Signal Transducing↗

PubMed2004

Progressive myeloma after thalidomide therapy in a patient with immature phenotype of myeloma (plasma) cells.

In our experience with thalidomide treatment for refractory multiple myeloma (MM), most patients with progressive disease (PD) did not show an increase in M-protein despite the tumor burden of myeloma cells. This finding led us to suspect that proliferation of immature myeloma cells showing MPC-1(-)/CD49e(-) phenotype may be a sign of PD. We report the results of consecutive analysis of the phenotype of myeloma (plasma) cells in an MM patient with PD during treatment with thalidomide. The myeloma cells decreased by thalidomide therapy were mature (MPC-1(+)/CD49e(+)) and intermediate (MPC-1(+)/CD49e(-)) types. When the patient was in the PD state, extramedullary plasmacytoma was recognized without proliferation of myeloma cells in the bone marrow (BM). The phenotype of myeloma (plasma) cells in both of these locations was that of immature myeloma cells (MPC-1(-)/CD49e(-)), and they showed decreased intensity of CD38 expression. The level of immunoglobulin G (IgG) in serum was decreased, and myeloma (plasma) cells in BM did not increase in PD. Although these clinical features may not be specific to MM patients in PD undergoing treatment with thalidomide, we suggest that immature myeloma cells may be resistant to thalidomide.

Aged↗

PubMed2004

[Chronic myelogenous leukemia following therapy for pineal germinoma].

A 13-year-old male was diagnosed as having pineal germinoma in July 1998. Since then, he had been treated with tumor excision, radiation and chemotherapy. In June 2002, he was diagnosed as having the chronic phase of chronic myelogenous leukemia (CML), and following treatment with interferon-alpha, he achieved hematological complete remission. Although CML is rare in secondary leukemia, the present case seemed therapy-related CML because of its clinical course, as the CML occurred after the period with radiation and chemotherapy. This is the first case of secondary CML following therapy for intracranial tumors.

Adolescent↗

PubMed2003

Islet cell hyperplasia in transgenic mice overexpressing EAT/mcl-1, a bcl-2 related gene.

EAT/mcl-1 (EAT), a bcl-2 related anti-apoptotic gene, is up-regulated at the early stage of differentiation of human embryonal carcinoma cells; cells which serve as a model for early embryogenesis. We generated transgenic mice for the human EAT gene driven by the EF1 alpha promoter in order to elucidate its functional role in vivo. Histologically, these mice exhibited hyperplasia of Langerhans islet cells; pancreatic cell regions composed of both insulin- and glucagon-producing cells. Furthermore, Bax and Bag-1 -- possible heterodimeric partners for EAT in the anti-apoptotic process -- were up-regulated in islets isolated from the EAT transgenic mice. The insulin tolerance test exhibited no significant difference between the EAT transgenic mice and non-transgenic mice, indicating that islet cell hyperplasia was not due to insulin resistance. In conclusion, EAT transgenic mice exhibit hyperplasia of pancreatic beta cells. EAT may inhibit apoptosis of beta cells, allowing these cells to circumvent the process of apoptosis until the adult stage.

Adenoma, Islet Cell↗

PubMed2003

Upregulation of Id2, an oncogenic helix-loop-helix protein, is mediated by the chimeric EWS/ets protein in Ewing sarcoma.

The chromosomal translocation specifically linked to the Ewing sarcoma family results in the generation of fusion proteins comprising the amino terminal portion of EWS and the DNA-binding domain of ets transcription factors. The EWS/ets chimeric proteins act as aberrant transcription factors leading to tumorigenic processes. We searched for genes specifically activated in Ewing sarcoma cells but not in other tumor cell lines using the gene array technique, and found significantly enhanced expression of the Id2 gene. High levels of Id2 transcripts were detected in Ewing sarcoma cell lines and tumor tissues. The EWS/ets chimeric proteins activated the Id2 gene via the 5'-upstream promoter sequence. Chromatin-immunoprecipitation revealed a direct interaction of EWS/Fli-1 with the promoter regions of the Id2, TGF-beta type II receptor, cyclin D1, and c-myc genes. Since EWS/Fli-1 transactivates c-myc, a cooperative action of the chimeric protein and c-myc leads to overexpression of Id2. In the present study, we suggest that Id2 is a target of the chimeric proteins and that the c-myc/Id2 pathway plays a pivotal role in the tumorigenic processes provoked by EWS/ets proteins.

Adolescent↗