The role of tumor lymphangiogenesis in metastatic spread

Overexpression of miR-486-5p suppresses tumor lymphangiogenesis in colorectal carcinoma by targeting neuropilin-2

AIM: To investigate the effect of microRNA-486-5p (miRNA-486-5p) overexpression on tumor lymphangiogenesis in colorectal carcinoma cells and to explore the underlying mechanism.

METHODS: A eukaryotic expression vector of miRNA-486-5p was transiently transfected into human colorectal carcinoma SW620 cells to induce miRNA-486-5p overexpression. A human colorectal carcinoma model in nude mice was then established, and the miRNA-486-5p vector was directly injected into local tumor tissue. Then, tumor size was measured every three days. The expression level of miRNA-486-5p in tumor tissue was determined by real-time PCR (RT-PCR). Meanwhile, the expression level of Neuropilin-2 (NRP2) and the number of lymphatic microvessels were detected by immunohistochemistry. The expression of NRP2 was measured by Western blot.

RESULTS: The expression of miRNA-486-5p increased significantly in the miRNA-486-5 transfected SW620 cells, and the mean expression level of miRNA-486-5p increased by 12.57 times ± 2.31 times after transfection. The growth speed of tumor in the miRNA-486-5p vector injected group was significantly slower than that in the control group (P < 0.05). The mass of tumor in the miRNA-486-5p vector injected group was significantly lower than that in the control group (P < 0.05). The expression of NRP2 and the number of lymphatic microvessels in the tumor tissue were also remarkably decreased in the miRNA-486-5p vector injected group (P < 0.05).

CONCLUSION: Overexpression of miRNA-486-5p could significantly inhibit the growth and lymphangiogenesis in colorectal carcinoma cells in vivo, and this might be related to the down-regulated expression of NRP2.