Nobuyuki Honma

Niigata University, Niahi-niigata, Niigata, Japan

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Publications (4)20.86 Total impact

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    ABSTRACT: The human hepatocellular carcinoma (HCC)-derived cell line KYN-2 is thought to provide a good model for studying the molecular basis of invasion and metastasis of human HCC, because it often shows cell scattering in vitro and intrahepatic metastasis in vivo. We previously found that integrin-mediated extracellular signals inactivated E-cadherin in KYN-2, and caused loss of cell-cell contact with gain of cell motility, which is considered to be a critical step in the process of cancer cell invasion and metastasis. To further understand molecular mechanisms involved in biological aggressiveness of HCC, we investigated intracellular signaling involved in integrin-mediated scattering of KYN-2 cells. Cultured KYN-2 cells formed trabecular aggregates in suspension, but when adhering to integrin-stimulating substrata, they scattered according to phosphorylation of extracellular signal-regulated kinase (ERK). Upon treatment with ERK kinase (MEK) inhibitor PD98059, adhered KYN-2 cell scattering was inhibited, tight cell-to-cell contact was recovered, and both E-cadherin and actin filaments accumulated in the area of intercellular contact zone. In contrast, constitutively active MEK1-transfected KYN-2 cells showed reduced E-cadherin and actin filaments in the intercellular contact zone, showing a flattened phenotype with broad lamellipodia. Enforced signaling of MEK-ERK pathway in KYN-2 cells suppressed cadherin-mediated homotypic adhesion and increased the potential of cell motility. An antibody-based protein microarray analysis revealed that the cytoplasmic protein c-Cbl was significantly downregulated in MEK1-transfected KYN-2 cells, suggesting that c-Cbl might be a candidate downstream mediator of integrin/MEK/ERK-mediated cell scattering. In conclusion, cell scattering of the highly metastatic cell line KYN-2 is regulated through the integrin-MEK-ERK signaling cascade, suggesting that this molecular pathway may be critical in intrahepatic metastasis of human HCC.
    Laboratory Investigation 08/2006; 86(7):687-96. · 3.83 Impact Factor
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    ABSTRACT: Here, we report a case of 70-year-old female with metastatic choroidal melanoma in the liver, which was detected 30 years after enucleation of the left eyeball. At first, two hypovascular tumors (4cm and 1cm in diameter) were detected in the liver as high-density areas on plain computed tomography (CT). They were demonstrated as hyper- and hypo-intensity lesions on T1- and T2-weighted image of magnetic resonance imaging (MRI), respectively, with superparamagnetic iron oxide uptake. During about 2-years follow-up, the larger tumor did not change significantly in size and in the character. However, the smaller one grew up in size and changed its nature to hypervascular and hyper-intensity on T2-weighted image of MRI. These hypervascular tumors increased in number and in size rapidly. The specimens obtained with tumor biopsy revealed epithelioid tumor cells positive for HMB45 immunohistochemical stain with and without brown pigment, and the tumors were diagnosed as melanoma. The patient underwent transcatheter arterial chemoembolization with cisplatin and epirubicin hydrochloride, and subsequent transcatheter arterial infusion chemotherapy with cisplatin, nimustine and dacarbazine. Unfortunately, however, the tumor rapidly progressed and she died. We discuss the imaging of the melanoma metastasized to the liver with the estimation of doubling time (DT) of the tumors.
    Hepatology Research 02/2004; 30(4):232-237. · 2.22 Impact Factor
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    ABSTRACT: Correlation between the gross classification of hepatocellular carcinoma (HCC) and its vascular invasion or intrahepatic metastasis has been reported previously. Because E-cadherin-mediated epithelial cell-to-cell adhesion is thought to suppress cancer cell invasion, the present study was performed to analyze the correlation between E-cadherin expression and the gross classification of HCC. Thirty-six resected solitary HCC <6 cm in diameter were each classified as single nodular type (type 1), single nodular with extranodular growth type (type 2) or contiguous multinodular type (type 3), and the clinicopathological and prognostic differences between type 1 HCC and the other types were analyzed. The expression of E-cadherin in each tumor was examined by immunoblotting and immunohistochemical analysis. Vascular invasion and microscopic intrahepatic metastasis were observed more frequently in types 2 and 3 (61%) than in type 1 (13%) HCC. Immunoblot analysis indicated that the relative level of E-cadherin expression in cancerous tissue was significantly lower in type 2 and 3 (0.75 +/- 0.49) than in type 1 (1.46 +/- 0.79) HCC. Immunohistochemical examination revealed decreased and partially absent E-cadherin expression in the tumorous area of type 2 and 3 HCC. The recurrence-free survival rate was higher for patients with type 1 HCC than for those with the other types. Types 2 and 3 HCC have marked metastatic and invasive potential and reduced expression of E-cadherin, predicting a high risk of recurrence after surgical treatment.
    Journal of Gastroenterology and Hepatology 06/2003; 18(6):673-7. · 3.63 Impact Factor
  • Hepatology 01/2003; 38:567-567. · 11.19 Impact Factor