[Study on inhibitory effect of combined administration of bear bile powder and cyclophosphamide on colorectal cancer liver metastasis by regulating tumor microenvironment].

OBJECTIVE: To explore the inhibitory effect of combined administration of bear bile powder (BBP) and cyclophosphamide (Cytoxan, CTX) on colorectal cancer liver metastasis by regulating tumor promotion inflammation microenvironment. METHOD: The CRC liver metastasis mode in mice was established through in situ spleenic injection of SL4 tumor cells into spleens. The mice were randomly divided into 5 groups: the model group, the CTX (80 mg x kg(-1)) treatment group, the CTX + BBP high dose (300 mg x kg(-1)) group, the CTX + BBP middle dose (150 mg x kg(-1)) group and the CTX + BBP low dose (75 mg x kg(-1)) group. Mice were orally administered with drugs for 12 days, and sacrificed on the 13'h day for weighing their spleens and lives, HE staining, and immunofluorescence analysis. Their peripheral blood, and metastatic tumor in spleens and lives were analyzed with flow cytometry. RESULT: Spleen and liver weights of the: CTX treatment group and other doses groups were significantly lower than that of the model group. HE staining and immunofluorescence analysis showed that lymphocyte infiltration was detected in normal tissues, and macrophages infiltration was observed around the tumor tissues. Flow cytometry analysis showed that the number of T-lymphocytes in peripheral blood of different doses groups were much higher than that of the CTX treatment group (P < 0.05), with the rise in the ratio of CD4/CD8; the total number of lymphocytes in spleen cell suspension increased in different doses groups, compared to the CTX treatment group, with notable increase in B cells (P < 0.05) and significant decrease in CD11b, F4/80 cells (P < 0.05). The combined treatment showed less monocyte macrophages in liver metastasis than that of the CTX treatment group. CONCLUSION: The combined treatment of bear bile powder and cyclophosphamide has the effect in not only protecting liver and increase immunity, but also in anti-inflammation and antitumor by regulating tumor microenvironment and reducing the collection of mononuclear macrophages. Particularly, the combined administration of low dose of bear bile powder and CTX shows the most significant effect in reducing inflammatory cell infiltration.

Knockout of CD8 delays reendothelialization and accelerates neointima formation in injured arteries of mouse via TNF-α inhibiting the endothelial cells migration.

OBJECTIVE: Delayed or impaired reendothelialization is a major cause of stent thrombosis in the interventional treatment of coronary heart disease. T cells are involved in neointima formation of injured arteries. However, the regulated mechanism of reendothelialization and the role of CD8 T cell in reendothelialization are unclear. METHODS AND RESULTS: Immunofluorescence staining showed that CD8 positive cells were increased in wire injured femoral artery of mice. On day 21 after injury, elastin staining showed that knockout of CD8 (CD8(-/-)) significantly increased intimal thickness and a ratio of intima to media by 1.8 folds and 1.9 folds respectively in injured arteries. Evans blue staining showed that knockout of CD8 delayed the reendothelialization area on day 7 after injury (18.8±0.5% versus 42.1±5.6%, p<0.05). In vitro, a migration assay revealed that CD8(-/-) T cells co-cultured with WT macrophages significantly inhibited the migration of the endothelial cells (ECs); compared to CD4(+) T cells, and CD8(+) T cells could promote the ECs migration. Furthermore, real-time PCR analysis showed that knockout of CD8 increased the level of tumor necrosis factor α (TNF-α) in injured arteries and cytometric bead cytokine array showed that TNF-α was elevated in cultured CD8(-/-) T cells. Finally, a wound-healing assay showed that recombinant TNF-α significantly inhibited the migration of ECs. CONCLUSION: Our study suggested that CD8(+) T cells could promote the reendothelialization and inhibit the neointima formation after the artery wire injury, and this effect is at least partly dependent on decreasing TNF-α production promoting ECs migration.