Yasuhiro Tamori

Immunohistochemical Analysis of Distribution of RON Receptor Tyrosine Kinase in Human Digestive Organs

The immunohistochemical distribution of RON receptor tyrosine kinase in digestive organs of both human fetus and adult, including the esophagus, stomach, duodenum, small intestine, colon, rectum, liver, gallbladder, pancreas, and spleen, was investigated semiquantitively using an affinity-purified rabbit polyclonal antibody. RON was observed to be widely distributed throughout various digestive organs and cell types in humans. The immunoreactivity for RON was observed in the epithelium of the esophagus, small intestine, colon, hepatocytes, Kupffer cells, and splenic macrophages both in the adult and the fetus, suggesting that the MSP/RON signaling pathway possesses the proper biological properties to possibly be involved in morphogenesis or differentiation of cells in these organs and cell types. Several organs differed in immunoreactivity between adult and fetus. No immunoreactive cells were found in the pancreas of adults; however, immunoreactivity was observed in acinar cells and in some of the duct or ductular cells and endocrine cells of the islet of the fetus. Similarly, immunoreactivity was not observed in gastric mucosa except in the intestinal metaplastic cells in adults; however, immunoreactivity was found in the foveolar epithelium of the stomach of the fetus. Although the biological significance of RON in malignancy is unclear, the presence of RON immunoreactivity in the fetus and it lack in the adult may indicate that RON is a oncofetal substance in human pancreas and stomach.

Immunohistochemical expression of SKALP/elafin in squamous cell carcinoma of human lung and esophagus

The immunohistochemical expression of skin-derived anti-leukoproteinase (SKALP)/elafin in lung squamous cell carcinoma (SqCC) and in uninvolved bronchial epithelium was studied. The results were compared with the immunohistochemical staining of proliferating cell nuclear antigen (PCNA) and the TDT-mediated dUTP-digoxigenin nick end labeling (TUNEL) assay. SKALP/elafin was expressed in SqCC with high incidence (82.6%). By contrast, the expression was not observed in uninvolved bronchial epithelium. SKALP/elafin expression was located in the cell layers just underneath the cornified envelope of each cell nest, and DNA fragmentation was observed in the same cell layers. PCNA was expressed in the basal layer of each cornified envelope, and both expressions were clearly separated. Immunoreactive score of SKALP/elafin expression was significantly correlated with the differentiation and it tended to increase in accordance with the degree of differentiation. These results suggested that SKALP/elafin was possibly involved in the cell differentiation program, finally leading to keratinization in SqCC of human lung. SKALP/elafin may be a beneficial molecular target for detection or even the development of a new therapeutic method against cancer.

Analysis of RON receptor tyrosine kinase and its splicing variant in malignant and non-malignant human colonic mucosa

Abstract The presence of RON and its variant isoform in malignant and non-malignant human colonic tissues was investigated by immunohistochemistry using paraffin-embedded sections and RT-PCR analysis followed by direct sequencing of PCR product using RNAs isolated from frozen tissues. In normal colonic mucosa of both human fetus and adult, RON was uniformly expressed in cript cells, especially in the bottom of cripta. On the other hand, the expression was distributed heterogeneously in adenomas and in colon cancer. The expression of RON was significantly related to the degree of differentiation of colon cancer. The RT-PCR analysis of RNA isolated from malignant and non-malignant colonic tissue revealed the presence of two RON mRNA isoforms. Direct sequencing of two major products was revealed to be identical to that of human wild-type RON and a splicing variant of RON transcript which has been reported in human gastric cancer cell line, KATO-III. It is indicated that both wild type RON and its valiant isoform play an important role in regulating the normal function of colonic mucosa such as differentiation and motile activity, and the expression of both wild-type RON and its valiant isoform could be considered to be reduced during malignancy of human colonic mucosa.

Induction of neutrophil elastase by TNF-α in human cancer cell lines

Abstract Similarities between cancer cells and neutrophil, such as circulating by single cells, attachment to the vascular system of the target and invasion into the target, lead to a hypothesis that cancer cells might produce neutrophil elastase or a very similar protease. Although the production of immunoreactive polymorphonuclear leukocyte elastase (ir-PMN-E) can be measured by enzyme immunoassay (EIA) in human cancer and cancer cell lines, we were having difficulty to detect this at mRNA level. TNF-α stimulation induces neutrophil elastase to a detectable level by RT-PCR in human cancer cell lines. In SUIT2, neutrophil elastase mRNA was detectable from 0.1 ng/ml of TNF-α stimulation which in EBC1 and MCF7 requires 1.0 ng/ml of TNF-α. For PC-3, there was no induction. The RT-PCR direct sequencing method revealed that the induced neutrophil elastase has no mutation. Although the amount of this molecule is low, as neutrophil elastase is a protease, the function in living systems does not depend on their amount but mainly on the activity they display. The result of this study indicates that some of the cancer cells could produce neutrophil elastase by stimulation of TNF-α and also suggests that neutrophil elastase produced by cancer cells is involved in clinical aspects of malignancy under inflammatory conditions.

Study of the Mechanism of Invasion and Metastasis in Pancreatic Cancer. Analysis of Cancer Cell Dissociation Factor.

膵臓癌の転移機構を明らかにする目的で, BOP誘導実験膵癌組織から樹立した高転移株 (PC-1・0) 培養上清中に存在する癌細胞解離因子 (DF) 分離精製し, その本態と膵癌の浸潤転移機構との関連について解析を行った. DFの精製を進め構成アミノ酸解析を行った結果, DFは新しいタイプのmetalloproteaseあるいはムチン様の構造をもつFc binding proteinであることが示唆された. 生物学的活性を解析した結果, DFには癌細胞コロニーを濃度依存的に解離し, 細胞運動能を増強させ, さらに, fibronectinに対する接着能を選択的に増強し, MATRIBGELに対する細胞浸潤能を増強する作用が存在した. 本研究の結果から, DFは膵臓癌の浸潤転移機構と密接に関連した生物学的特性を有する新しい因子であることが示唆された.