It was recently reported that the human CD109 gene encodes a glycosyl-phosphatidylinositol-anchored glycoprotein that is a member of the a 2 -macroglobulin/C3, C4, C5 family of thioester-containing proteins. In this study, we found that the expression of mouse CD109 gene was upregulated in NIH3T3 cells expressing RET tyrosine kinase with a multiple endocrine neoplasia 2B mutation. Northern blot analysis showed a high level of expression of the CD109 gene only in the testis in normal human and mouse tissues. In addition, its expression was high in some human tumor cell lines, which included squamous cell carcinoma and glioblastoma cell lines, whereas it was undetectable in neuroblastoma and small-cell lung carcinoma cell lines. When CD109 expression was examined in 33 cases of human lung cell carcinomas by quantitative RT-PCR, a significant high expression of CD109 was detected in about half of squamous cell carcinomas examined, but not in adenocarcinoma, large-cell carcinoma and small-cell carcinoma. Similarly, upregulation of CD109 was observed in nine out of 17 esophageal squamous cell carcinomas. Thus, these results suggested that CD109 might be a useful molecular target for the development of new therapeutics for malignant tumors, such as squamous cell carcinoma.

Ruthenium alkylidene 1 has been utilized in the tandem ring opening−ring closing metathesis of cyclic olefins. This reaction produces a bicyclic molecule from a cyclic olefin. Reactivity is dependent upon strain, and thus ring size, in the substrate molecules. Competing oligomerization is observed in substrates having low ring strain; this process is inhibited by increasing dilution of the reaction or by adding alkyl substitution to the acyclic olefins.

Germ-line point mutations of the RET gene are responsible for multiple endocrine neoplasia (MEN) type 2A and 2B that develop medullary thyroid carcinoma and pheochromocytoma. We performed a differential display analysis of gene expression using NIH 3T3 cells expressing the RET-MEN2A or RET-MEN2B mutant proteins. As a consequence, we identified 10 genes induced by both mutant proteins and eight genes repressed by them. The inducible genes include cyclin D1, cathepsins B and L, and cofilin genes that are known to be involved in cell growth, tumor progression, and invasion. In contrast, the repressed genes include type I collagen, lysyl oxidase, annexin I, and tissue inhibitor of matrix metalloproteinase 3 (TIMP3) genes that have been implicated in tumor suppression. In addition, six RET-MEN2A-and five RET-MEN2B-inducible genes were identified. Among 21 genes induced by RET-MEN2A and/or RET-MEN2B, six genes including cyclin D1, cathepsin B, cofilin, ring finger protein 11 (RNF11), integrin-␣6, and stanniocalcin 1 (STC1) genes were also induced in TGW human neuroblastoma cells in response to glial cell line-derived neurotrophic factor stimulation. Because the STC1 gene was found to be highly induced by both RET-MEN2B and glial cell line-derived neurotrophic factor stimulation, and the expression of its product was detected in medullary thyroid carcinoma with the MEN2B mutation by immunohistochemistry, this may suggest a possible role for STC1 in the development of MEN 2B phenotype. The RET proto-oncogene encodes a receptor tyrosine kinase with a cadherin-related motif and a cysteine-rich domain in the extracellular domain and is located on chromosome 10q11.2.1,2 It has been demonstrated that RET is a functional receptor for four related neurotrophic factors including glial cell line-derived neurotrophic factor (GDNF), neurturin, artemin, and persephin. These factors are known to require glycosylphosphatidylinositol-anchored co-receptors, GFR-␣s, as ligand-binding components and to promote the survival of various central and peripheral neurons in culture.1,2 In addition, gene knockout studies revealed that the GDNF/RET signaling plays a crucial role in the development of the enteric nervous system and the kidney. [3][4][5][6] Germline mutations of the RET gene cause dominant inherited cancer syndromes; multiple endocrine neoplasia (MEN) type 2A and 2B.7-10 MEN 2A is characterized by the development of medullary thyroid carcinoma (MTC), pheochromocytoma, and parathyroid hyperplasia. MEN 2B shows a more complex phenotype with association of MTC, pheochromocytoma, and developmental abnormalities such as mucosal neuroma, hyperganglionosis of the intestinal tract, and marfanoid skeletal changes. The MEN2A mutations were identified in cysteine residues of the RET extracellular domain, leading to ligand-independent RET dimerization. 11,12 The MEN2B mutations were detected in methionine at codon 918 or in alanine at codon 883 in the tyrosine kinase domain and appear to activate RET without dimerization. 12,13 A variety of si...

CD109 is a cell surface protein, a member of the alpha(2) macroglobulin/C3,C4,C5 family of thioester-containing proteins. The authors have recently reported that high expression of the CD109 gene was detected in approximately half of the examined lung and esophageal squamous cell carcinomas as well as in the testis, and that CD109 has the characteristics of a cancer-testis antigen. In the present study CD109 expression in cervical squamous cell carcinoma was compared with that in endometrial adenocarcinoma by reverse transcription polymerase chain reaction (RT-PCR). The result demonstrated that CD109 expression is significantly higher in cervical squamous cell carcinomas than in endometrial adenocarcinomas and normal cervix and endometrium. In contrast, when expression of RET finger protein (RFP) and bromodomain testis-specific (BRDT) genes, which are also known to be highly expressed in the testis, was examined, no significant difference in their expression levels was observed between squamous cell carcinomas and adenocarcinomas. These findings suggest that CD109 may become a molecular target for the development of new therapeutics for squamous cell carcinoma of various tissue origins.

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