Role of MDC/CCL22-CCR4 axis in mouse milky spots with peritoneal carcinomatosis of gastric cancer

Objective To study role of MDC/CCI22-CCR4 axis in mouse milky spots with peritoneal carcinomatosis of gastric cancer. Methods We examined the expression of CCR4 in 615 Mouse gastric cancer cell (MFC) lines by RT-PCR and Western-blot; Peritoneal metastasis model on the 615mouse was established by intraperitoneal injection of 0.2 ml MFC cells(1×104 cells). Dil fluorescence was used to observe the transfer process and section of MFC. Immunohistochemistry was conducted to detect the expression of CCR4 and CCL22 in omental milky spot; the structure of Milky spot was observed by scanning electron microscopy. Mice were randomly divided into 2 groups, namely, the saline control group (received saline) and MFC group. The concentration of CCL22 in ascitic fluid was measured in the 615 mice injected MFC after 6,8,10 days and in the saline group. Results MFC first metastasizes to the milky spot on the omentum, the expression of CCR4 and CCL22 were observered in the milky spot. The surface layer cells in milky spot consisted of discontinuous mesothelial cells and mainly macrophages and lymphocytes. The average value of CCL22 was 43 pg/ml and 364 pg/ml respectively in saline control group and MFC group.Conclusions MDC/CCL22-CCR4 axis plays an important role in the development of peritoneal carcinomatosis in mouse gastric cancer. Key words: Stomach neoplasms;  Neoplasm metastasis;  Chemokine CCL2;  Milky spot