Abnormal activation of growth factor receptors and their signal pathways are required for neoplastic transformation and tumor progression. The concept of targeting specific tumorigenic receptors has been validated by successful clinical application of multiple new drugs, such as those acting against HER2/neu, epidermal growth factor receptor 1, and c-Kit. In this review, we focus on the next promising therapeutic molecular target of insulin-like growth factor (IGF)-I receptor (IGF-Ir). The IGF/IGF-Ir system is an important modifier of cancer cell proliferation, survival, growth, and treatment sensitivity in a number of neoplastic diseases, including human gastrointestinal carcinomas. Preclinical studies demonstrated that downregulation of IGF-Ir signals reversed the neoplastic phenotype and sensitized cells to antitumor treatments. We summarize a variety of ways to disrupt IGF-Ir function. Then, we introduce our strategy of adenoviruses expressing dominant negative of IGF-Ir (IGF-Ir/dn) against gastrointestinal cancers, including stomach, colon, and pancreas. IGF-Ir/ dn suppresses tumorigenicity both in vitro and in vivo and increases stressor-induced apoptosis. IGF-Ir/dn expression upregulates chemotherapy-induced apoptosis and these combination therapies with chemotherapy are very effective against tumors in mice. Some drugs blocking IGF-Ir function are now entering clinical trial, thus IGF-Ir might be a candidate for a therapeutic target in several gastrointestinal malignancies.

AIM:To clarify the clinicopathological significance of laminin-5 γ2 (LNγ2) and β3 (LNβ3) chains and MMP7 expression in biliary tract cancer. METHODS:We analyzed the association between immunohistochemically detected LNγ2, LNβ3, and MMP7 expression in biliary tract cancer and clinicopathological characteristics. Activity of MMP7 was analyzed by casein zymography. An in vitro invasion assay after treatment with MMP7-specific siRNA was performed. RESULTS:LNγ2 expression was predominantly observed in carcinoma cells at the invasive front. LNγ2 expression was seen in 57% of patients with biliary tract cancer, and was associated with depth of invasion, histologic type, and advanced stage. The expression pattern of LNβ3 was classified into two types: invasive front dominant type (38%) and diffuse type (28%).The invasive front dominant type was associated with histologic type and advanced stage. MMP7 positivity was correlated with LNγ2 or LNβ3 expression but not with clinicopathological characteristics. Active MMP7 detected by casein zymography was correlated with depth of invasion and advanced stage. Downregulation of MMP7 expression by siRNA resulted in a significant decrease in biliary tract cancer cell invasion in vitro . CONCLUSION:Our results suggest that LNγ2 and LNβ3, in conjunction with MMP7, play a key role in the progression of biliary tract cancer.

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summaryA 73-year-old woman had experienced dry mouth and swellings of both upper eyelids from 1998. In October 2003, she also developed bilateral submandibular swellings, and was diagnosed with diabetes mellitus and prescribed antidiabetic medication. She consulted our hospital in the summer of 2004 due to the exacerbation of eyelid swelling, and was admitted in October 2004. Keratoconjunctivitis sicca was not present. CT and MRI of the head showed bilateral enlargement of the lacrimal and submandibular glands. Serological investigations revealed hypergammaglobulinemia, but as antinuclear antibody and anti-SS-A antibody were absent, further investigation was performed. Serum concentrations of IgG4 were elevated and biopsy of the minor salivary gland revealed a severe inˆltration of IgG4-positive plasmacytes. The patient was therefore diagnosed with Mikulicz's disease. Abdominal CT demonstrated diŠuse pancreatic swelling, and endoscopic retrograde cholangio-pancreatography revealed stricture of the common bile duct and main pancreatic duct, suggesting the complication of autoimmune pancreatitis. Treatment was commenced with 40 mg/day of prednisolone. This resulted in rapid resolution of the lacrimal and submandibular gland swellings and recovery of salivary gland function. DiŠuse swelling of the pancreas and stricture of the common bile duct and main pancreatic duct also improved, and endogenous insulin secretion increased. Both Mikulicz's disease and autoimmune pancreatitis presented with elevated serum IgG4 and inˆltration of IgG4-expressing plasma cells into the glandular tissues. We recently proposed the new diagnostic entity of``IgG4-related plasmacytic exocrinopathy'' ; however, if diabetes mellitus in autoimmune pancreatitis was caused by direct dysfunction of pancreatic ? cells, we must reconsider this pathogenesis and consider a wider concept including exocrine as well as endocrine glands. This case, in which both types of glands were aŠected, is therefore of considerable interest.

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