A Novel Experimental Mouse Model of Peritoneal Dissemination of Human Gastric Cancer Cells: Analysis of the Mechanism of Peritoneal Dissemination Using cDNA Macroarrays

We established a new cell line, NUGC‐3P4T, with high peritoneal metastatic disseminating potential in nude mice. NUGC‐3P4T cells were derived from the human gastric carcinoma line NUGC‐3, which has low capacity for peritoneal dissemination. NUGC‐3P4T cells developed peritoneal dissemination in 10/10 (100%) mice, whereas the parental NUGC‐3 cells developed dissemination in 1/5 (20.0%) mice. The metastatic foci in the peritoneum showed essentially the same histological appearance as those induced by parental cells. The tumorigenicity, the motile activity and the adhesive activity to the laminin of NUGC‐3P4T cells were stronger than those of NUGC‐3 cells. Production of IL‐8 was significantly higher in NUGC‐3P4T than in NUGC‐3. cDNA macroarrays analysis showed that a variety of cytokines, interleukins, and other immunomodulators and their receptors were up‐ or down‐regulated at the mRNA level in NUGC‐3P4T cells, compared with NUGC‐3 cells. Thus, this unique cell line and in vivo model might be useful to study the biology of peritoneal dissemination of human gastric cancer.