Effect of hepatoma H22 on lymphatic endothelium in vitro.

AIM: To determine the effect of metastatic hepatoma cells on lymphangioma-derived endothelium, and to establish in vitro model systems for assessing metastasis-related response of lymphatic endothelium. METHODS: Benign lymphangioma, induced by intraperitoneal injection of the incomplete Freund’s adjuvant in BALB/c mice, was embedded in fibrin gel or digested and then cultured in the conditioned medium derived from hepatoma H22. Light and electron microscopy, and the transwell migration assay were used to determine the effect of H22 on tissue or cell culture. Expressions of Flt-4, c-Fos, proliferating cell nuclear antigen (PCNA), and inducible nitric oxide synthase (iNOS) in cultured cells, and content of nitric oxide in culture medium were also examined. RESULTS: The embedded lymphangioma pieces gave rise to array of capillaries, while separated cells from lymphangioma grew to a cobblestone-like monolayer. H22 activated growth and migration of the capillaries and cells, induced expressions of Flt-4, c-Fos, PCNA and iNOS in cultured cells, and significantly increased the content of NO in the culture medium. CONCLUSION: Lymphangioma-derived cells keep the differentiated phenotypes of lymphatic endothelium, and the models established in this study are feasible for in vitro study of metastasis-related response of lymphatic endothelium.