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Biomedical subjects

A Gotoh

Publications and source records attributed to A Gotoh.

At least 91 records · Page 5Linked to original sources
PubMed1996

Steel factor induces serine phosphorylation of Stat3 in human growth factor-dependent myeloid cell lines.

Steel factor (SLF) acts synergistically with various hematopoietic growth factors that use the Jak-Stat pathways in vivo and in vitro, although the contribution by SLF to this pathway is unknown. We show here that SLF induces time- and dose-dependent phosphorylation of Stat3 in the human growth factor-dependent cell lines MO7e and TF-1. This phosphorylation occurs exclusively on serine residues. Simultaneous stimulation with SLF plus other cytokines that induce tyrosine phosphorylation of Stat3, such as interleukin-9 (IL-9) in MO7e cells or IL-6 in TF-1 cells, resulted in tyrosine phosphorylation and enhanced serine phosphorylation of Stat3. Serine phosphorylation alone did not promote nuclear translocation or DNA binding activity to the sis-inducible element of Stat3. However, costimulation with SLF plus IL-9 in MO7e cells resulted in the nuclear translocation of serine-hyperphosphorylated Stat3. Serine phosphorylation of Stat3 was also observed by the stimulation of cells with granulocyte-macrophage colony-stimulating factor and IL-3, which do not induce tyrosine phosphorylation of Stat3. These results suggest that SLF might modulate the Jak-Stat3 pathway by serine phosphorylation and that the Jak-Stat pathway may be differentially regulated by the combinational stimulation of two or more cytokines.

Base Sequence↗
PubMed1996

Immobilized anti-KIT monoclonal antibody induces ligand-independent dimerization and activation of Steel factor receptor: biologic similarity with membrane-bound form of Steel factor rather than its soluble form.

Interaction of a tyrosine kinase type receptor and its ligand induces receptor-dimerization or -oligomerization followed by transphosphorylation and activation of its intrinsic kinase, which leads to a series of intracellular signals. We have previously reported that the membrane-bound form of Steel factor (SLF) induces more persistent tyrosine kinase activation and longer life span of c-kit encoded protein (KIT) than its soluble form (Miyazawa et al, Blood 85:641, 1995). In this study, we used YB5.B8 monoclonal antibody (MoAb) that recognizes the extracellular domain of KIT to investigate whether immobilized anti-KIT MoAb can substitute for SLF as a potent activator of KIT by cross-linking receptors and further compared its effect with each SLF isoform in a factor-dependent cell line M07e. YB5.B8 MoAb in a soluble state suppressed SLF-induced M07e cell proliferation in a dose-dependent manner. By contrast, once this antibody was immobilized on the goat-antimouse MoAb (GAM)-coated culture plates, it supported the growth of M07e cells in the absence of any growth factors, whereas culture the cells in GAM alone or YB5.B8 without GAM-coated plates resulted in rapid cell-death within 24 hours. As with the natural ligand SLF, immobilized YB5.B8 MoAb synergized with granulocyte-macrophage colony-stimulating factor (GM-CSF) in inducing cell proliferation compared with either YB5.B8 MoAb or GM-CSF alone. Immunoblotting with antiphosphotyrosine MoAb showed that interaction of M07e cells with immobilized YB5.B8 induced tyrosine phosphorylation of a series of intracellular proteins including KIT (145 kD). In addition, cross-linking studies using a water-soluble cross linking reagent bis-sulfosuccinimidyl-suberate showed that immobilized YB5.B8 MoAb induced dimerization and activation of KIT. However, as with stimulation by the membrane-bound form of SLF, the kinetics of KIT activation with YB5.B8 MoAb was more prolonged compared with the cells treated with recombinant soluble SLF. Flow cytometry showed that, unlike the cells treated with soluble SLF, no downmodulation of cell-surface KIT expression was observed in M07e cells cultured with immobilzed YB5.B8 MoAb. These data suggest that immobilized antibodies against hematopoietic receptors may replace their ligand-stimulators; however, their activities may resemble the membrane-bound form rather than the soluble form of natural ligands.

Amino Acid Sequence↗
PubMed1996

Inhibitory effect of a nucleoside analog, acyclovir, on leukemia cells.

Acyclovir (ACV), a nucleoside analog, has been demonstrated previously to suppress selectively the proliferation of NIH3T3 fibroblastic cells transformed by either v-abl or bcr-abl gene transfection. From a viewpoint of clinical application of ACV, we investigated whether ACV inhibited the growth of leukemia cells expressing either p210 BCR-ABL or p185BCR-ABL. Acyclovir exerted an inhibitory effect on OM9;22 cells, p185BCR-ABL expressing cells, in a dose-dependent manner. Despite no down-modulation of a BCR-ABL tyrosine kinase activity or its expression was observed after treatment with ACV, cell cycle analysis demonstrated synchronization of OM9;22 cells at the G0/G1 phase. This suggests that, although ACV does not directly act on BCR-ABL tyrosine kinase, ACV may exert its inhibitory effect on some leukemia cell lines via alterations of the cell cycle. Although selective inhibition of Philadelphia chromosome-positive leukemia cell growth was not apparent, our data provides a therapeutic possibility for ACV in the treatment for leukemia.

Acyclovir↗
PubMed1996

Two cases of small cell carcinoma of the prostate.

We describe the clinical and pathological findings in two Japanese men with small cell carcinoma of the prostate; case 1 was 58 years old and case 2 was 24 years old. Case 1 was initially diagnosed as a poorly differentiated adenocarcinoma of the prostate, stage D2, with marked elevation of serum neuron-specific enolase (NSE), carcinoembryonic antigen (CEA), and CA 19-9 levels. The patient had undergone castration and systemic chemotherapy. After three courses of chemotherapy, tumour markers were normalized. However, 6 months later serum levels of tumour markers again rose, and biopsy of the prostate revealed a small cell carcinoma component in the adenocarcinoma of the prostate and benign prostate hypertrophy. The patient was again treated with systemic chemotherapy but died within 1 year after relapse. In case 2, the patient presented with initial symptoms of lumbago and dysuria, and an enlarged prostate was radiologically diagnosed. Shortly after admission he developed ileus, and an exploratory laparotomy revealed a large tumour arising from the prostate and invading the peritoneal cavity. This tumour was pathologically diagnosed as a small cell carcinoma. The patient died shortly thereafter without responding to chemotherapy. Immunohistological evaluation was done using a panel of antibodies against NSE, chromogranin A, CEA, CA 19-9, prostatic acid phosphatase (PAP), prostate-specific antigen (PSA), leukocyte common antigen (LCA), epithelial membrane antigen (EMA), adrenocorticotropic hormone (ACTH), calcitonin, serotonin, gastrin, vasoactive intestinal peptide (VIP), and glucagon. CEA was intensely positive in the tumour lesions from case 1, and NSE and ACTH were focally positive, and calcitonin, serotonin, CA 19-9, and PSA were weakly positive only in several cells in the tumour lesions from case 1. In the tumour lesion from case 2, NSE was intensely positive, and chromogranin A was weakly positive. These findings support the neuroendocrine nature of this neoplasm.

Adenocarcinoma↗
PubMed1996

[High activity of antistreptolysin-O in a case of IgM myeloma].

A 56-year-old man was admitted to our hospital in November, 1991 because of hyperproteinemia and anemia. Total protein showed 12 g/dl and serum immunoglobulins were as follows; IgG 974 mg/dl, IgA 142 mg/dl, IgM 9270 mg/dl. M-component was identified as IgM-kappa with immunoelectrophoresis and serum viscosity indicated 6.9. Although the patient had no history of severe streptococcal infection, his serum showed very high activity of ASLO (6890 IU/ml). Bence Jones protein was detected in the urine and determined to be of kappa-type. Plasma cells occupied 43% of bone marrow nucleated cells and their cytoplasms were stained with FITC-labeled anti-IgM and anti-kappa antibodies. X-ray examination disclosed punched out lesions in the skull. Consequently, the patient was diagnosed as having IgM-myeloma. At first, VCAP regimens were given after plasmapheresis, but had no effect. Therefore, the patient was treated with CHOP protocol and the serum IgM decreased in amount and the proportion of bone marrow myeloma cells got down to 17%. ASLO titer also decreased in parallel with IgM. These findings suggest that IgM in this case had ASLO activity.

Antistreptolysin↗
PubMed1996

[Radical prostatectomy for localized prostate cancer].

We studied 81 patients who underwent radical prostatectomy for prostate cancer. Ten, 57 and 14 patients were clinically diagnosed with stage T1, T2 and T3, respectively. Pelvic lymph node dissection was performed prior to prostatectomy in all cases. The neurovascular bundle was preserved in 21 patients. Compared with pathological stage, the accuracy rate of clinical staging in T1, T2 and T3 was 40, 46 and 64% respectively. Approximately half of the patients clinically diagnosed with stage T2 were pT3. The positive rate of lymph node in pT2 and pT3 was 3.3 and 37% respectively, showing a marked difference between these two pathological stages. The 3-year non-recurrence rates were 89% in patients with pT2 and 79% in pT3. In the well differentiated carcinoma group, no patients had recurrence for up to 3 years. All of the patients with infiltration (INF) gamma showed recurrence within 3 years. Fifty-five patients had no problem on urination post-operatively, while the other 23 patients had a mild or moderate incontinence and the remaining 3 patients had a small urine stream. Regarding erectile potency, 4 out of 18 evaluable patients were potent.

Aged↗
PubMed1995

Membrane-bound Steel factor induces more persistent tyrosine kinase activation and longer life span of c-kit gene-encoded protein than its soluble form.

Alternative splicing of exon 6 results in the production of two isoforms of Steel factor (SLF): the membrane-bound and soluble forms. To investigate differences in the kinetics of c-kit tyrosine kinase activated by these two isoforms, we used a stromal cell line (SI/SI4) established from SI/SI homozygous murine embryo fetal liver and its stable transfectants containing either hSCF248 cDNA (including exon 6; secreted form) or hSCF220 cDNA (lacking exon 6; membrane-bound form) as the source of each isoform. Interaction of factor dependent myeloid cell line MO7e with stromal cells producing either isoform resulted in activated c-kit tyrosine kinase and induction of the same series of tyrosine phosphorylated cellular proteins in MO7e cells. However, SI4-h220 (membrane-bound form) induced more persistent activation of c-kit kinase than SI4-h248 (soluble form) did. Flow cytometric analysis and pulse-chase studies using [35S]methionine showed that SI4-h248 induced rapid downmodulation of cell-surface c-kit expression and its protein degradation in MO7e cells, whereas SI4-h220 induced more prolonged life span of c-kit protein. Addition of soluble recombinant human SLF to SI4-h220 cultures enhanced reduction of cell-surface c-kit expression and its protein degradation. Because the kinetics of c-kit inactivation strikingly fits with the protein degradation rates of c-kit under the conditions described above, rapid proteolysis of c-kit protein induced by soluble SLF stimulation may function as a "turn-off switch" for activated c-kit kinase.

Alternative Splicing↗
PubMed1995

[Tuberculous spondylitis after intravesical BCG instillation: a case report].

We report a case of tuberculous spondylitis after intravesical bacillus Calmette-Guerin (BCG) instillation. A 71-year-old man was administered BCG (80 mg per week) for 8 weeks for prophylactic treatment of bladder cancer. After the first instillation he experienced miction pain, pollakisuria, and febrile episodes. Two months after the completion of BCG instillation, he complained to back pain and spinal X-ray showed a lytic lesion of Th7 vertebra. Diagnosis of metastatic transitional cell carcinoma was made based on MRI and bone scan. But pathological findings at laminectomy revealed tuberculous spondylitis. Antituberculous therapy (SM, RFP, and INH) was instituted and anterior supine fusion was performed. Now he is free from bladder cancer and tuberculous infection. Intravesical BCG instillation is effective for superficial bladder cancer, but it should be kept in mind that complications related to this treatment could occur and the adequate antituberculosis treatment has to be insisted if indicated.

Administration, Intravesical↗
PubMed1995

Tyrosine phosphorylation and activation of focal adhesion kinase (p125FAK) by BCR-ABL oncoprotein.

Focal adhesion kinase (p125FAK; FAK) is a protein tyrosine kinase that is tyrosine-phosphorylated in response to v-src-mediated transformation, cell adhesion, and stimulation with neuropeptides. To elucidate a possible functional relationship between FAK and BCR-ABL oncoprotein detected in Philadelphia chromosome-positive (Ph+) leukemias, we investigated the tyrosine phosphorylation state of FAK in a murine growth factor-dependent cell line and in its stable human bcr-abl cDNA transfectant. In interleukin-3 (IL-3)-dependent NFS/N1.H7 cells, tyrosine phosphorylation of FAK was not detected after stimulation with either IL-3 or Steel factor (SLF), both of which involve Ras-mediated signaling pathways. However, stable gene transfection with p210bcr-abl cDNA into H7 cells made these cells growth factor-independent for proliferation and resulted in constitutive tyrosine phosphorylation and kinase activation of FAK. Constitutive phosphorylation and activation of FAK was also observed in all Ph+ leukemia cell lines examined--that is, K562, TS9;22, and YS9;22, which express p210BCR-ABL, and NALM-21 and OM9;22, which express p185BCR-ABL. Ph-negative (Ph-) cell lines, such as MO7e and JM, did not show any detectable tyrosine phosphorylation of FAK. FAK phosphorylation in BCR-ABL-expressing cells was inhibited in a dose-dependent manner by cytochalasin D, a reagent that disrupts the intracellular network of actin filaments. However, no suppression of kinase activity or protein expression of BCR-ABL was observed after treatment with cytochalasin D. A physical association between BCR-ABL and FAK was not apparent. These data suggest that BCR-ABL may be involved in the activation of FAK. Moreover, FAK may be distinct from components in Ras-mediated signaling cascades that are activated by stimulation of myeloid cells with various cytokines.

Animals↗
PubMed1995

[Bilateral testicular Leydig cell tumor with adrenocortical adenoma: a case report].

A case of bilateral testicular Leydig cell tumor with left adrenocortical adenoma in a 27-year-old male is presented. He underwent bilateral radical orchiectomy, and was diagnosed with a malignant Leydig cell tumor. Computed tomography revealed left adrenal mass and primary adrenal tumor or metastatic malignant Leydig cell tumor was suspected. Left adrenalectomy was performed and the histopathological diagnosis was adrenal cortical adenoma. The adrenal cortex and testicle are of common mesodermal origin and the histologic pattern may overlap. Examination of the adrenal gland is necessary for patients with testicular Leydig cell tumor. We review and briefly discuss a case recently reported in Japan.

Adenoma↗
PubMed1995

Bilateral peripelvic fat simulating renal pelvic tumor.

Lipomas are benign tumors which may simulate peripelvic masses and usually originate in the renal cortex or the perirenal adipose tissue. Excessive proliferation of the peripelvic fat of the kidney simulating a renal pelvic tumor was detected in our case, illustrating a rare instance in which the kidney was salvaged.

Adipose Tissue↗
PubMed1994

Ligand-dependent polyubiquitination of c-kit gene product: a possible mechanism of receptor down modulation in M07e cells.

Quantities of proteins in cells are balanced by protein synthesis and degradation. Protein ubiquitination is an important adenosine-triphosphate dependent proteolytic pathway for "short-lived" proteins. We show that soluble steel-factor (SLF) stimulation at 37 degrees C rapidly induced polyubiquitination of c-kit protein in growth-factor-dependent human-myeloid cell line M07e, resulting in smeared, retarded migration of c-kit protein in sodium dodecyl sulfate-polyacrylamide gel electrophoresis in the molecular weight region of 145 kD. Receptor ubiquitination was almost completely absent when cells were treated with SLF at 4 degrees C or at 37 degrees C in the presence of 0.2% sodium azide, or when the cells were pretreated with anti-c-kit monoclonal antibody or genistein, a tyrosine-kinase inhibitor. This suggested that c-kit ubiquitination was ligand dependent and appeared to require intrinsic tyrosine-kinase activation of the c-kit protein. Flow-cytometric analysis of c-kit expression on the cell surface of M07e cells showed down modulation of c-kit within 5 minutes after soluble-SLF treatment at 37 degrees C. However, rapid receptor down modulation was almost completely suppressed when cells were treated with SLF at 4 degrees C or at 37 degrees C in the presence of 0.2% sodium azide, conditions that concomitantly suppressed polyubiquitination of c-kit protein. In addition, these conditions almost completely suppressed radiolabeled SLF (125I-SLF) internalization after ligand-receptor interaction. Pulse-chase studies of 35S-methionine-labeled c-kit protein showed that SLF stimulation at 37 degrees C strikingly enhanced c-kit degradation (T1/2; approximately 20 minutes) compared with that in cells stimulated with SLF at 4 degrees C or at 37 degrees C with 0.2% sodium azide. However, in the presence of chloroquine, which blocks lysosomal degradation, this ligand-induced c-kit degradation at 37 degrees C was only suppressed in part. These data suggest that SLF-induced polyubiquitination of the c-kit receptor protein may play a role in regulation of c-kit-encoded protein-receptor expression in M07e cells.

Amino Acid Sequence↗
PubMed1994

[Small cell carcinoma of the prostate].

Small cell carcinoma of the prostate is a rare disease, since only about 50 cases in the English literature and two cases in Japanese literature have been reported. Here we report a case that is the youngest ever described in the literature. A 24-year-old man was referred to our hospital with right dull lumbago and dysuria. He had the same symptom for one and half year before referral. IVP showed right non-visualizing kidney and left hydronephrosis. Form abdominal CT scans and cystoscopic findings a retrovesical tumor was highly suspicious. Transperineal needle biopsy specimens revealed an undifferentiated malignant tumor. His serum Neuron Specific Enolase (NSE) and LDH were remarkably high and whole body CT scan and upper GI tract examination demonstrated no lesion. He developed ileus and underwent exploratory laparotomy and colostomy was constructed. There was a large mass arising from the prostate which invaded into the peritoneal cavity, and multiple metastases were seen on the omentum and mesenteric lymph nodes. Specimens from the mass arising from the prostate and lymph nodes revealed small cell carcinoma pathologically. A panel of antibodies were used to seek potential tumor markers and to identify substances produced by the tumor cells including enzymes, cytoskeletal components and hormones. And stains were positive for the NSE and chronogranin. An intensive anti-cancer chemotherapy with VP-16 and CDDP was done with minor response (MR) and the serum tumor marker, LDH and NSE, decreased markedly. However, he had expired on the 58th hospital day.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

A case of papillary renal cell carcinoma suggestive of Bellini duct origin.

A case of Bellini duct carcinoma is reported. A left renal tumor was detected by abdominal computerized tomography in a 76-year-old male, although he had no symptoms, such as hematuria, weight loss or flank pain. Radical nephrectomy was performed under the diagnosis of renal cell carcinoma in the left kidney. Macroscopic examination of the resected kidney revealed a tumor 2.0 cm in diameter, with a yellow-brown cut surface, located in the renal medulla. Histological examinations showed malignant tumor cells with eosinophilic cytoplasm with a papillary growth pattern. Immunohistostaining examinations using Lectin and two kinds of monoclonal antibodies demonstrated no significant staining with soybean agglutinin, peanut agglutinin, Dolichos biflorus agglutinin, Lotus tetragonolobus agglutinin or cytokeratin, and negative staining with Tamm-Horsfall protein. Although the results of immunohistostaining did not provide support, both macroscopic and microscopic findings strongly suggested that this tumor originated from Bellini duct epithelium (Bellini duct carcinoma). The patient is alive with no evidence of disease 1 year after surgery. Bellini duct carcinoma is a rare malignant condition and the prognosis is usually poor. Differential diagnosis from other renal or pelvic tumors is difficult and long-term careful follow-up is necessary.

Aged↗
PubMed1994

Potential molecules implicated in downstream signaling pathways of p185BCR-ABL in Ph+ ALL involve GTPase-activating protein, phospholipase C-gamma 1, and phosphatidylinositol 3'-kinase.

Constitutive activation of BCR-ABL tyrosine kinase fusion protein has been shown to be an essential step in the pathogenesis of Philadelphia chromosome (Ph)-positive leukemias. We studied the tyrosine phosphorylated proteins which might be involved in the signaling pathway p185BCR-ABL using a Ph-positive acute lymphoblastic leukemia cell line. p185BCR-ABL but not p145c-abl was constitutively phosphorylated on tyrosine in this cell line. p21ras GTPase-activating protein (GAP) was physically associated with p185BCR-ABL, but not with p145c-abl, and GAP-associated proteins p62/p190 were found to be tyrosine-phosphorylated. Furthermore, p185BCR-ABL was also physically associated with phospholipase C-gamma 1 (PLC-gamma) and phosphatidylinositol 3'-kinase (P13-kinase). Concomitantly, both PLC-gamma and p85 subunit of P13-kinase are tyrosine-phosphorylated in the cells with p185BCR-ABL. These data suggest that GAP, GAP-associated proteins, PLC-gamma, and P13-kinase may participate in downstream signaling for p185BCR-ABL tyrosine kinase.

Animals↗