Keiichi Kontani

Galectin-9 Induces Maturation of Human Monocyte-Derived Dendritic Cells

Maturation of dendritic cells (DCs) is critical for initiation of immune responses and is regulated by various stimulatory signals. We assessed the role of galectin (Gal)-9 in DC maturation. Culture of immature DCs with exogenous Gal-9 markedly increased the surface expression of CD40, CD54, CD80, CD83, CD86, and HLA-DR in a dose-dependent manner, although Gal-9 had no or little effect on differentiation of human monocytes into immature DCs. Gal-9-treated DCs secreted IL-12 but not IL-10, and they elicited the production of Th1 cytokines (IFN-γ and IL-2) but not that of the Th2 cytokines (IL-4 and IL-5) by allogeneic CD4+ T cells. These effects of Gal-9 on immature DCs were not essentially dependent on its lectin properties, given that they were inhibited only slightly by lactose. We further found that a Gal-9 mutant that lacks β-galactoside binding activity reproduced the above activities and that an anti-Gal-9 mAb suppressed them. Gal-9 induced phosphorylation of the MAPK p38 and ERK1/2 in DCs, and an inhibitor of p38 signaling, but not inhibitors of signaling by either ERK1/2 or PI3K, blocked Gal-9-induced up-regulation of costimulatory molecule expression and IL-12 production. These findings suggest that Gal-9 plays a role not only in innate immunity but also in acquired immunity by inducing DC maturation and promoting Th1 immune responses.

Wnt5a Expression Is Associated With the Tumor Proliferation and the Stromal Vascular Endothelial Growth Factor—An Expression in Non–Small-Cell Lung Cancer

PURPOSE The Wnt gene family encodes the multifunctional signaling glycoproteins. We performed the present study to investigate the clinical significance of Wnt5a expression in non-small-cell lung cancer (NSCLC). PATIENTS AND METHODS One hundred twenty-three patients with NSCLC who had undergone resection were investigated. Real-time quantitative reverse transcriptase polymerase chain reaction was performed to evaluate the Wnt5a gene expression. Immunohistochemistry was performed to investigate the Wnt5a protein expression, the Ki-67 proliferation index, tumor angiogenesis, and the expression of beta-catenin and vascular endothelial growth factor-A (VEGF-A). RESULTS Wnt5a gene expression in squamous cell carcinoma was significantly higher than that in adenocarcinoma (P < .0001). There was a significant correlation between the normalized Wnt5a gene expression ratio and the intratumoral Wnt5a protein expression (r = 0.729; P < .0001). The intratumoral Wnt5a expression was significantly correlated with the Ki-67 proliferation index (r = 0.708; P < .0001). In contrast, no correlation was observed between the intratumoral Wnt5a expression and tumor angiogenesis. Furthermore, the intratumoral Wnt5a expression was significantly correlated with the stromal expression of beta-catenin (r = 0.729; P < .0001) and VEGF-A (r = 0.661; P < .0001). In addition, the stromal VEGF-A expression was also correlated with Ki-67 proliferation (r = 0.627; P < .0001). Cox regression analyses demonstrated Wnt5a status to be a significant prognostic factor for NSCLC patients (P = .0193), especially for patients with squamous cell carcinomas (P = .0491). CONCLUSION The present study revealed that an overexpression of Wnt5a could produce more aggressive NSCLC, especially in squamous cell carcinomas, during tumor progression.

Galectin-9 increases Tim-3+ dendritic cells and CD8+ T cells and enhances antitumor immunity via galectin-9-Tim-3 interactions.

A Tim-3 ligand, galectin-9 (Gal-9), modulates various functions of innate and adaptive immune responses. In this study, we demonstrate that Gal-9 prolongs the survival of Meth-A tumor-bearing mice in a dose- and time-dependent manner. Although Gal-9 did not prolong the survival of tumor-bearing nude mice, transfer of naive spleen cells restored a prolonged Gal-9-induced survival in nude mice, indicating possible involvement of T cell-mediated immune responses in Gal-9-mediated antitumor activity. Gal-9 administration increased the number of IFN-γ-producing Tim-3+ CD8+ T cells with enhanced granzyme B and perforin expression, although it induced CD4+ T cell apoptosis. It simultaneously increased the number of Tim-3+CD86+ mature dendritic cells (DCs) in vivo and in vitro. Coculture of CD8+ T cells with DCs from Gal-9-treated mice increased the number of IFN-γ producing cells and IFN-γ production. Depletion of Tim-3+ DCs from DCs of Gal-9-treated tumor-bearing mice decreased the number of IFN-γ-producing CD8+ T cells. Such DC activity was significantly abrogated by Tim-3-Ig, suggesting that Gal-9 potentiates CD8+ T cell-mediated antitumor immunity via Gal-9-Tim-3 interactions between DCs and CD8+ T cells.

Galectin-9 as a Prognostic Factor with Antimetastatic Potential in Breast Cancer

Purpose: Galectin-9, a member of the β-galactoside–binding galectin family, induces aggregation of certain cell types. We assessed the contribution of galectin-9 to the aggregation of breast cancer cells as well as the relation between galectin-9 expression in tumor tissue and distant metastasis in patients with breast cancer. Experimental Design: Subclones of MCF-7 breast cancer cells with high or low levels of galectin-9 expression were established and either cultured on plastic dishes or transplanted into nude mice. The tumors of 84 patients with breast cancer were tested for galectin-9 expression by immunohistochemistry. The patients were followed up for 14 years. Results: MCF-7 subclones with a high level of galectin-9 expression formed tight clusters during proliferation in vitro, whereas a subclone (K10) with the lowest level of galectin-9 expression did not. However, K10 cells stably transfected with a galectin-9 expression vector aggregated in culture and in nude mice. Ectopic expression of galectin-9 also reduced MCF-7 cell adhesion to extracellular matrix proteins. Tumors of 42 of the 84 patients were galectin-9 positive, and those of 19 of the 21 patients with distant metastasis were galectin-9 negative. None of the 13 patients with galectin-9–positive tumors and lymph node metastasis up to level II manifested distant metastasis. The cumulative disease-free survival ratio for galectin-9–positive patients was more favorable than that for the galectin-9–negative group (P < 0.0001). Multivariate analysis revealed that galectin-9 status influenced distant metastasis independently of and to a greater extent than lymph node metastasis. Conclusions: Galectin-9 is a possible prognostic factor with antimetastatic potential in breast cancer.

Truncating mutations of RB1CC1 in human breast cancer.

The protein RB1CC1 (retinoblastoma 1 (RB1)-inducible coiled-coil 1) has been identified as a key regulator of the tumor-suppressor gene RB1 (ref. 1). RB1CC1 is localized in the nucleus and has been proposed to be a transcription factor because of its nuclear localization signal, leucine zipper motif and coiled-coil structure. The gene RB1CC1 is localized to a region of chromosome 8q11 (ref. 2) containing several loci of putative tumor-suppressor genes; however, its role in human cancers remains to be determined. Here we report that 20% (7 of 35) of primary breast cancers examined contained mutations in RB1CC1, including nine large interstitial deletions predicted to yield markedly truncated RB1CC1 proteins. Wildtype RB1CC1 and RB1 were absent or significantly less abundant than normal in the seven cancers with mutations in RB1CC1, but were abundant in cancers without such mutations. In all seven cancers, both RB1CC1 alleles were inactivated; two showed compound heterozygous deletions. Thus, RB1CC1 is frequently mutated in breast cancer and shows characteristics of a classical tumor-suppressor gene.

Identification of RB1CC1, a novel human gene that can induce RB1 in various human cells.

Multidrug resistance to anti-cancer agents (MDR) is a major barrier to successful cancer treatment. Current knowledge about genes that contribute to MDR is limited, however, and its mechanisms remain unclear. To identify genes involved in MDR, we performed differential display analysis and isolated a novel human gene, RB1CC1 (RBI-inducible Coiled-Coil 1). The 6.6-kb RB1CC1 cDNA encodes a putative 1594-amino-acid protein that contains a nuclear localization signal, a leucine zipper motif and a coiled-coil structure. Western blot analysis and immunocytochemical staining with anti-RB1CC1 antibody showed that endogenously expressed RB1CC1 protein localized to the nucleus. In MDR variants of human osteosarcoma cells, RB1CC1 expression increased in response to doxorubicin-induced cytotoxic stress and remained elevated for the duration of drug treatment. RB1CC1 expression levels correlated closely with those of RB1 (retinoblastoma 1 ) in cancer cell lines as well as in various normal human tissues. Moreover, introduction of wild-type RB1CC1 significantly induced RB1 expression in human leukemic cells. These data suggest that RB1CC1 may be a key regulator of RB1 gene expression.

Malignant lymphoma of mucosa‐associated lymphoid tissue arising in the thymus of a patient with sjögren's syndrome

A 59‐year‐old woman with Sjögrens syndrome had an anterior mediastinal tumor. The tumor had epithelium‐lined thymic cysts. Histologically, centrocyte‐like (CCL) cells were present as clusters intermingling with small lymphocytes and plasma cells, invaded the epithelium, and formed characteristic lymphoepithelial lesions; the tumor was identified as malignant lymphoma arising in mucosa‐associated lymphoid tissue (MALT). Within the tumor, trapped Hassalls corpuscles were recognized. Immunohistochemical staining demonstrated monotypic cytoplasmic kappa light chains in a small portion of the CCL cells. Furthermore, Southern blot hybridization studies showed rearrangements of immunoglobulin heavy chain, immunoglobulin kappa light chain, and T‐cell receptor beta genes. The findings are consistent with thymic low‐grade B‐cell MALT lymphoma. Cancer 1992; 69:1347‐1355.

Recovery of parathyroid function after total thyroidectomy : Long-term follow-up study

Background:  To prevent postoperative hypoparathyroidism following total thyroidectomy, the parathyroid glands are preserved in situ and/or resected or devascularized parathyroid glands are autotransplanted. A retrospective investigation was conducted utilizing biochemical and specific endocrine assessments to evaluate the difference in recovery of parathyroid function in the long term.

Modulation of MUC1 mucin as an escape mechanism of breast cancer cells from autologous cytotoxic T-lymphocytes.

MUC1 mucin is known to serve as a target molecule in the killing of breast cancer cells by cytotoxic T-lymphocytes (CTLs). We searched for a possible mechanism allowing tumour cells to escape from autologous CTLs. When the killing of breast cancer cells by autologous lymphocytes was examined in 26 patients with breast cancer, significant tumour cell lysis was observed in 8 patients, whereas virtually no autologous tumour cell lysis was detected in as many as 18 patients. In the patients who showed negligible tumour cell lysis, the autologous tumour cells expressed MUC1-related antigenic epitopes much more weakly than the tumour cells in the patients who exhibited strong cytotoxicity (significant statistically at P< 0.0005–0.0045), suggesting that the unresponsiveness of cancer cells to CTLs observed in these patients was mainly due to loss of MUC1 expression or modulation of its antigenicity. A breast cancer cell line, NZK-1, established from one of the cytotoxicity-negative patients, did not express MUC1 and was resistant to killing by CTLs, while control breast cancer cell lines expressing MUC-1 were readily killed by CTLs. Transfection of NZK-1 cells with MUC1 cDNA induced significant lysis by autologous T-lymphocytes. These results supported the importance of MUC1 mucin in autologous anti-tumour immunity, but suggested that the major escape mechanism of tumour cells from autologous T-lymphocytes is the loss and/or modulation of MUC1 antigenicity on tumour cells, which would limit the effectiveness of possible immunotherapy designed to target the MUC1 mucin.

Expression and Immunogenicity of a Tumor- Associated Antigen, 90K/Mac-2 Binding Protein, in Lung Carcinoma The Possibility of Its Clinical Use as a Tumor Marker and a Target Antigen in Cancer Immunotherapy

The authors attempted to obtain shared proteins among lung carcinoma cells by column chromatographies. A glycoprotein with approximately 500 kDa isolated from QG56 cells showed an identical amino acid sequence to 90K/Mac‐2 binding protein (M2BP). This protein has been reported to be highly expressed and to modulate the expression of surface molecules involved in immune responses on cultured cancer cells. Therefore, it would be beneficial for M2BP to be targeted in cancer immunotherapy.