Downregulation of monocarboxylate transporter 1 inhibits the invasion and migration through suppression of the PI3K/Akt signaling pathway in human nasopharyngeal carcinoma cells

Monocarboxylate transporter 1 (MCT1) has been reported to be correlated wtih decreased survival and advanced stage of progression in a series of human tumor cells and primary cancers. Specifically, MCT1 has been documented to be involved in tumor progression, including invasion and migration. Here, we investigated the mechanism and effect of regulation of MCT1 on invasion and migration of nasopharyngeal carcinoma (NPC) cells. In the study, we firstly demonstrated that the expression of MCT1 in CNE2Z cells was obviously higher than that in HNE1 cells. Downregulation of MCT1 inhibited the invasion and migration in CNE2Z cells, upregulated the expression of E-cadherin, TIMP (tissue inhibitor of metalloproteinase)-2 and TIMP-1, and suppressed the expression of matrix metalloproteinases (MMP)-9 and MMP-2. Correspondingly, upregulation of MCT1 enhanced the invasive and migratory potential in HNE1 cells, increased the expression of MMP-9 and MMP-2, and downregulated the expression of E-cadherin, TIMP-2 and TIMP-1. The mechanistic study demonstrated that the effect of MCT1 might be correlated with PI3K/Akt signaling pathway. LY294002, a PI3K inhibitor, increased the inhibition of invasion and migration mediated by downregulation of MCT1 in CNE2Z cells. These findings collectively suggested that MCT1 might act as a new regulator to improve invasion and migration of NPC cells and be correlated with activating the PI3K/Akt pathway.