Koki Nagaike

Hepatocyte Growth Factor Activator Inhibitor Type 1 (HAI-1) Is Required for Branching Morphogenesis in the Chorioallantoic Placenta

ABSTRACT Hepatocyte growth factor activator inhibitor type 1 (HAI-1) is a membrane-associated Kunitz-type serine proteinase inhibitor that was initially identified as a potent inhibitor of hepatocyte growth factor activator. HAI-1 is also a cognate inhibitor of matriptase, a membrane-associated serine proteinase. HAI-1 is expressed predominantly in epithelial cells in the human body. Its mRNA is also abundant in human placenta, with HAI-1 specifically expressed by villous cytotrophoblasts. In order to address the precise roles of HAI-1 in vivo, we generated HAI-1 mutant mice by homozygous recombination. Heterozygous HAI-1+/− mice underwent normal organ development. However, homozygous HAI-1−/− mice experienced embryonic lethality which became evident at embryonic day 10.5 postcoitum (E10.5). As early as E9.5, HAI-1−/− embryos showed growth retardation that did not reflect impaired cell proliferation but resulted instead from failed placental development and function. Histological analysis revealed severely impaired formation of the labyrinth layer, in contrast all other placental layers, such as the spongiotrophoblast layer and giant cell layer, which were formed. Our results indicate that mouse HAI-1 is essential for branching morphogenesis in the chorioallantoic placenta and lack of HAI-1 function may result in placental failure.

Activation of c-Met (hepatocyte growth factor receptor) in human gastric cancer tissue.

c‐Met is a high‐affinity receptor for hepatocyte growth factor (HGF) and plays a crucial role in embryonic development, as well as in the process of tissue repair. Overexpression and amplification of c‐Met are often observed in various cancer tissues, especially in gastric carcinoma. It has, however, been unclear whether the overexpression leads to activation of the c‐Met receptor. To address this point, we prepared an antibody (anti‐phospho‐Met) which specifically recognizes c‐Met that is phosphorylated at Y1235, a major phosphorylation site of c‐Met. Normal as well as cancerous gastric tissue was positive for anti‐total‐Met staining, whereas only cancerous tissue was strongly positive for anti‐phospho‐Met staining; cells near the basal layer were moderately positive, and the proliferative zone in normal tissue was only weakly positive. Among cancerous tissues from seven patients examined in the present study, those from six patients were strongly positive for phospho‐Met staining. These results indicate that c‐Met is actually activated in gastric carcinoma tissue, and may trigger proliferation/anti‐apoptotic signals.

Defect of Hepatocyte Growth Factor Activator Inhibitor Type 1/Serine Protease Inhibitor, Kunitz Type 1 (Hai-1/Spint1) Leads to Ichthyosis-Like Condition and Abnormal Hair Development in Mice

Hepatocyte growth factor activator inhibitor type 1 (HAI-1)/serine protease inhibitor, Kunitz type 1 (SPINT1) is a membrane-bound, serine proteinase inhibitor initially identified as an inhibitor of hepatocyte growth factor activator. It also inhibits matriptase and prostasin, both of which are membrane-bound serine proteinases that have critical roles in epidermal differentiation and function. In this study, skin and hair phenotypes of mice lacking the Hai-1/Spint1 gene were characterized. Previously, we reported that the homozygous deletion of Hai-1/Spint1 in mice resulted in embryonic lethality attributable to impaired placental development. To test the role of Hai-1/Spint1 in mice, the placental function of Hai-1/Spint1-mutant mice was rescued. Injection of Hai-1/Spint1(+/+) blastocysts with Hai-1/Spint1(-/-) embryonic stem cells successfully generated high-chimeric Hai-1/Spint1(-/-) embryos (B6Hai-1(-/-High)) with normal placentas. These embryos were delivered without apparent developmental abnormalities, confirming that embryonic lethality of Hai-1/Spint1(-/-) mice was caused by placental dysfunction. However, newborn B6Hai-1(-/-High) mice showed growth retardation and died by 16 days. These mice developed scaly skin because of hyperkeratinization, reminiscent of ichthyosis, and abnormal hair shafts that showed loss of regular cuticular septation. The interfollicular epidermis showed acanthosis with enhanced Akt phosphorylation. Immunoblot analysis revealed altered proteolytic processing of profilaggrin in Hai-1/Spint1-deleted skin with impaired generation of filaggrin monomers. These findings indicate that Hai-1/Spint1 has critical roles in the regulated keratinization of the epidermis and hair development.

Role of cancer cell-stroma interaction in invasive growth of cancer cells

Invasive growth is one of the hallmarks of cancer malignancy. To date, a significant body of evidence is accumulating in favor of the notion that invasive growth results from the cross-talk between cancer cells and the host stromal cells, comprising fibroblasts (myofibroblasts), endothelial cells, and leukocytes, all of which are themselves invasive. In this review we describe cross-talk between invasive cancer cells and host stromal fibroblasts and an impact of pericellular microenvironment on the invasive phenotype of cancer cells, focusing on two molecules, extracellular matrix metalloproteinase inducer (EMMPRIN, also known as tumor cell-derived collagenase stimulatoty factor, basigin, CD147) and hepatocyte growth factor (HGF, also known as scatter factor). Both molecules are deeply involved in the regulation of invasion-associated cellular activities, such as pencellular proteolysis, migration and ectopic sunrival of cancer cells.

Multiple hepatic peribiliary cysts with cirrhosis

Multiple hepatic peribiliary cysts were found in three autopsy cases of patients who had had underlying liver diseases and obstructive jaundice. Macroscopically, the cysts were visible and present exclusively in the hepatic hilum and larger portal tracts. Histologically, the cysts were of varying size and were lined by a single layer of cuboidal or flattened epithelial cells without atypia. Intimate association between the cysts and peribiliary glands was found in the walls of large bile ducts. All three cases were associated with liver cirrhosis in patients with portal hypertension, and two of the patients had also had hepatocellular carcinoma. These findings support the previous assumption that multiple hepatic peribiliary cysts may be closely related to a portal hypertensive condition. Although peribiliary cysts have been considered to be clinically asymptomatic in general, in one of our patients, the cystic dilatation appeared to have been responsible for the progression of obstructive jaundice.

Prognostic significance of circumferential cell surface immunoreactivity of glypican‐3 in hepatocellular carcinoma

Background: GC33 is a recently developed monoclonal antibody against human glypican‐3 (GPC3), which is significantly upregulated in hepatocellular carcinoma (HCC). GC33 recognizes a GPC3 ectodomain and shows significant antitumour activity in vivo. Thus, humanized GC33 antibody may be a promising tool for treating HCC having cell surface GPC3 expression.

Paradoxically enhanced immunoreactivity of hepatocyte growth factor activator inhibitor type 1 (HAI‐1) in cancer cells at the invasion front

We have previously demonstrated significantly decreased immu‐noreactivity of hepatocyte growth factor activator inhibitor type 1 (HAI‐1), an integral membrane protein that exhibits potent inhibitory activity against hepatocyte growth factor activator (HGFA) and matriptase, in colorectal adenocarcinomas. In this report, we describe further detailed analysis of HAI‐1 expression in colorectal adenocarcinoma by using three kinds of anti‐HAI‐1 antibodies, each of which recognizes a distinct epitope of the HAI‐1 molecule, and also by in‐situ hybridization for HAI‐1 mRNA. The results indicated that the decreased immunoreactivity of HAI‐1 in colorectal carcinoma cells is largely a result of enhanced ecto‐domain shedding of HAI‐1 in these cells. In contrast, immunore‐activity of mature membrane‐form HAI‐1 was paradoxically enhanced in cancer cells at the invasion front, showing intense cell‐stroma interactions and/or sprouting invasion. This finding indicates that these invading cells showed decreased ectodomain shedding of HAI‐1 and consequently might require the existence of the membrane‐form HAI‐1. Of particular interest was the observation of a possible inverse correlation between paradoxical up‐regulation of membrane‐form HAI‐1 expression and membrane‐associated E‐cadherin in these cells. These membrane‐form HAI‐1‐positive sprouting cancer cells were also negative for MIB‐1 immunohistochemically, indicating a low‐proliferating population. All these results suggest that HAI‐1 may mediate diverse functions in regard to the progression of colorectal carcinomas, and the immunoreactivity of membrane‐form HAI‐1 may serve as a marker of invading cancer cells.

An unusual variant of a left paraduodenal hernia diagnosed and treated by laparoscopic surgery: Report of a case

An 80-year-old woman who had undergone both a cholecystectomy and an appendectomy presented with intermittent abdominal pain. Computed tomography (CT) revealed an encapsulated circumscribed cluster of jejunal loops in the left upper quadrant. The hernia orifice was adjacent to the left side of the superior mesenteric artery and vein. An upper gastrointestinal series also revealed a cluster of jejunal loops, suggesting the possibility of an internal hernia. Laparoscopic surgery was performed. The hernia orifice was found to be caused by abnormal adhesion between the transverse mesocolon and the jejunum mesentery. An adhesiotomy reduced the jejunum entrapped in the hernia. The hernia space was a large mesocolic fossa composed of transverse mesocolon and mesentery, continuing to the splenic flexure. The hernia was classified as a variant of paraduodenal hernia.

Synchronous adenocarcinoma and gastrointestinal stromal tumors of the stomach treated laparoscopically

Gastric adenocarcinomas account for approximately 95% of primary gastric tumors, and gastrointestinal stromal tumor (GIST) is the most common gastrointestinal mesenchymal tumor, accounting for 1%–3% of primary gastric tumors. However, the synchronous occurrence of GIST and gastric epithelial tumor is rare. We herein report a case of synchronous occurrence of gastric adenocarcinoma and two GISTs of the stomach. All lesions were resected laparoscopically. We discuss this case and review the literature.

Main-duct intraductal papillary mucinous adenoma of the pancreas with a large mural nodule

Intraductal papillary mucinous neoplasm (IPMN) is an increasingly recognized entity representing a spectrum of benign and malignant neoplasms of the pancreas. Preoperative distinction between benign and malignant IPMNs remains difficult. Reported predictive factors for malignancy are size of the main pancreatic duct, cystic neoplasm, and mural nodule. We report herein the case of a 50-year-old woman in whom a large mural nodule (30 mm) in the dilated main pancreatic duct (16 mm in diameter) was detected by ultrasonography, computed tomography, and endoscopic retrograde cholangiopancreatography. Because the large mural nodule and dilatation of the main pancreatic duct were also detected by endoscopic ultrasonography (EUS) and intraductal ultrasonography (IDUS), the main-duct IPMN was considered to have malignant potential. Thus, pylorus-preserving pancreaticoduodenectomy with lymph node dissection was performed. The resected intraductal tumor appeared polypoid with a broad stalk and comprised a proliferation of mucin-containing columnar epithelial cells with papillary structures without malignant features. The final diagnosis was intraductal papillary mucinous adenoma of the pancreas. The size of the mural nodule and the final diagnosis in this case suggest that the introduction of a novel molecular-biological approach might be necessary for the precise preoperative diagnosis of main-duct IPMN and adequate surgical treatment.