Influence of lymphatic endothelial cells on proliferation and invasiveness of esophageal carcinoma cells in vitro and lymphangiogenesis in vivo

The aim of the study was to investigate the interaction between esophageal carcinoma cells with different differentiation degree and esophageal carcinoma-related lymphatic endothelial cells. Different lymphatic endothelial cell conditioned mediums were used to cultivate well-differentiated esophageal carcinoma EC9706 cells and poorly differentiated esophageal carcinoma KYSE150 cells, and immunocytochemistry and Western blot analyses were applied to detect the expression of MMP-9 protein and TIMP-2 protein in each group; in situ hybridization and RT-PCR methods were used to detect the expression of MMP-9 and TIMP-2 mRNA in each group; CCK-8 method was used to detect cell proliferation in each group; and transwell method was utilized to detect cell invasiveness in each group. Through constructing the transplanted tumor model of esophageal carcinoma of nude mice, the D2-40 and LYVE-1 immunohistochemical staining was performed on transplanted tumors and surrounding tissues, lymphatic microvessels were marked, and lymphatic microvessel density (LMVD) was measured. The expression of MMP-9 protein and mRNA in experimental group was significantly higher than that in control groups (P < 0.05); TIMP-2 protein and mRNA expression in experimental group was significantly lower than that in control groups (P < 0.05); cell proliferation ability and invasiveness ability in experimental group were significantly higher than those in control groups (P < 0.05); LMVD-marked D2-40 and LMVD-marked LYVE-1 of transplanted tumor tissue in the experimental group were significantly higher than those in control groups (P < 0.05). The esophageal squamous carcinoma-related lymphatic microvessel could promote the proliferation and invasive ability of esophageal squamous carcinoma cells in vitro. It had different effects on esophageal carcinoma cells with different differentiation degree and had more obvious influence on poorly differentiated esophageal carcinoma cells, which may be related to the up-regulated MMP-2 expression and down-regulated TIMP-2 expression of esophageal carcinoma cells. The esophageal squamous carcinoma-related lymphatic microvessel endothelial cells could promote the growth of esophageal carcinoma-transplanted tumor of nude mice and lymphangiogenesis.