Metastasis-associated protein 1 induces VEGF-C and facilitates lymphangiogenesis in colorectal cancer

AIM:To study the correlation between high metastasisassociated protein 1(MTA1)expression and lymphangiogenesis in colorectal cancer(CRC)and its role in production of vascular endothelial growth factor-C(VEGF-C). METHODS:Impact of high MTA1 and VEGF-C expression levels on disease progression and lymphovasculardensity(LVD,D2-40-immunolabeled)in 81 cases of human CRC was evaluated by immunohistochemistry. VEGF-C mRNA and protein expressions in human LoVo and HCT116 cell lines were detected by real-time polymerase chain reaction and Western blotting,respectively,with a stable expression vector or siRNA. RESULTS:The elevated MTA1 and VEGF-C expression levels were correlated with lymph node metastasis and Dukes stages(P<0.05).Additionally,high MTA1 expression level was correlated with a large tumor size(P< 0.05).A significant correlation was found between MTA1 and VEGF-C protein expressions in tumor cells(r=0.371, P<0.05).Similar to the VEGF-C expression level,high MTA1 expression level was correlated with high LVD in CRC(P<0.05).Furthermore,over-expression of MTA1 significantly enhanced the VEGF-C mRNA and protein expression levels,whereas siRNAs-knocked down MTA1 decreased the VEGF-C expression level. CONCLUSION:MTA1,as a regulator of tumor-associated lymphangiogenesis,promotes lymphangiogenesis in CRC by mediating the VEGF-C expression.