CD109 is a glycosylphosphatidylinositol (GPI)-anchored glycoprotein whose expression is up-regulated in squamous cell carcinomas (SCCs) of the lung, esophagus, and uterus. The purpose of this study was to evaluate CD109 expression in oral tumors, including premalignant lesions, and to assess the clinical application of CD109 in oral cancer. CD109 expression in oral normal and tumor tissues from 124 patients was examined by immunohistochemical staining with anti-CD109 antibody, and significant relations between clinical features and CD109 expression were statistically assessed. We found that high levels of CD109 expression were frequently detected in SCCs and premalignant lesions of the oral cavity, but not in normal squamous epithelia. The CD109 expression level was higher in well-differentiated SCCs than in poorly differentiated SCCs. Furthermore, premalignant lesions highly expressing CD109 showed higher risk to progress to SCCs. Oral SCC cell lines overexpressing CD109 exhibited accelerated cell growth in vitro compared with control cell lines. In addition, overexpression of CD109 impaired the transforming growth factor (TGF)-b1-mediated suppression of cell growth. These findings suggest that CD109 plays a role in the development of oral cancers, and is a useful prognostic marker to predict malignant transformation of premalignant lesions. (Cancer Sci 2008; 99: 1916-1923 U p-regulation or down-regulation of the expression of some genes, including oncogenes and tumor suppressor genes, trigger the development of human tumors; the products of these genes are potentially good molecular targets for cancer diagnosis and treatment. In oral cancers, despite the ease of clinical examination, most cancer patients are diagnosed with advanced-stage cancer and are difficult to treat because of the anatomic location of the lesions or because the treatment would impact on the patients' quality of life. Therefore, early diagnosis of high-risk premalignant lesions is most important for good prognosis.CD109 is a glycosylphosphatidylinositol (GPI)-anchored cellsurface glycoprotein and is a member of the α2-macroglobulin-C3, C4, and C5 family of thioester-containing proteins.(1-3) The CD109 protein was first identified as a cell-surface antigen detected by a monoclonal antibody raised against the primitive lymphoid/ myeloid cell line KG1a.(1) It has been reported that CD109 is expressed on a subset of fetal and adult CD34 + bone marrow mononuclear cells, mesenchymal stem cell subsets, phytohemagglutinin (PHA)-activated T lymphoblasts, thrombin-activated platelets, leukemic megakaryoblasts, endothelial cells, and some human tumor cell lines, but not on fresh peripheral leukocytes and normal bone marrow leukocytes.(1,2,4,5) It was also shown that CD109 carries the biallelic platelet-specific alloantigen Gov, which is implicated in refractoriness to platelet transfusion, post-transfusion purpura, and neonatal alloimmune thrombocytopenia. We identified CD109 as a gene up-regulated in cells overexpressing oncogenic RET tyrosine kinas...

CD109 is a glycosylphosphatidylinositol (GPI)-anchored glycoprotein, whose expression is upregulated in squamous cell carcinomas of the lung, esophagus, uterus and oral cavity. CD109 negatively regulates transforming growth factor (TGF)-b signaling in keratinocytes by directly modulating receptor activity. In this study, we further characterized CD109 regulation of TGF-b signaling and cell proliferation. We found that CD109 is produced as a 205 kDa glycoprotein, which is then processed in the Golgi apparatus into 180 kDa and 25 kDa proteins by furin (furinase). 180 kDa CD109 associated with GPI-anchored 25 kDa CD109 on the cell surface and was also secreted into the culture medium. To investigate whether furinase cleavage of CD109 is necessary for its biological activity, we mutated arginine 1273 in the CD109 furinase cleavage motif (amino acid 1270-RRRR-1273) to serine (R1273S). Interestingly, CD109 R1273S neither significantly impaired TGF-b signaling nor affected TGF-b-mediated suppression of cell growth, although it was expressed on the cell surface as a 205 kDa protein. Consistent with this finding, the 180 kDa and 25 kDa CD109 complex, but not CD109 R1273S, associated with the type I TGF-b receptor. These findings indicate that processing of CD109 into 180 kDa and 25 kDa proteins by furin, followed by complex formation with the type I TGF-b receptor is required for the regulation of TGF-b signaling in cancer cells and keratinocytes.

The effect of hyperthermia on cervical lymph node metastasis of VX7 tongue cancer in female Japanese white rabbits was investigated. Magnetoliposomes (MLs) with a neutral surface charge and a size of 94.1 nm were used as heating mediators. MLs were injected into the tongue 20 days after tumor transplantation, and we examined whether they reached the metastatic deep cervical lymph node. The highest magnetite concentration 24 h after ML injection was detected in the lymph node, followed by tongue, spleen, blood, and liver. Rabbits were separated into three groups: group I as the control; group II with ML injection alone; and group III with ML injection and hyperthermia 24 h after ML injection, generated by applying an alternating magnetic field (118 kHz, 384 Oe) to the neck region. The hyperthermic effect was evaluated in terms of the percentage of necrosis in proportion to the metastatic tumor and the apoptotic index (AI), defined as the ratio of TUNEL-positive cells. The temperature of lymph nodes in group III reached over 44°C. The mean area of necrosis in group III was 58.0%, which was significantly higher than that in group I (19.6%) or group II (20.4%). The AI in group III was 22.9%, significantly higher than in group I (1.67%) or II (1.42%). The difference between group I and II was not statistically significant. he presence of cervical lymph node metastasis of head and neck cancer is a negative prognostic factor. The major modalities presently available for treating highly advanced head and neck cancer include surgery, radiotherapy and chemotherapy, but even the combination of all three modalities has limited efficacy. No therapeutic method has been established for cases with cervical lymph node metastasis, and the results of treatments used to date have been unsatisfactory: even with intensive radiochemothermotherapy, more than 60% of these patients die as a result of uncontrollable local progressions of the cervical lymph node metastases.1) The use of hyperthermia has generally been confined to cervical lymph node metastasis accessible with a radiofrequency system using external applicators, in combination with synergistic chemoradiotherapy. We earlier concluded that the goal of preoperative thermochemoradiotherapy is to reduce cervical lymph node metastases to surgically treatable size, and complete removal at surgery remains a critical part of treatment.2) Hyperthermia is appealing because it is a physical treatment with fewer side effects than chemotherapy and radiotherapy, and repeated treatments should be feasible without concern for cumulative toxic side effects. However, almost all recent hyperthermia methods heat not only the tumor, but also normal tissue, which is damaged by nonspecific heating. A new method to heat only the tumor and a new heating mediator for this purpose are needed. Some researchers have been investigating submicron magnetic particles as heating mediators. [3][4][5] We have recently developed magnetite particles with a cationic liposomal membrane, 'magnetite cationic liposome...

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