Eukaryotic elongation factor 2 kinase up-regulates the expression of proteins implicated in cell migration and cancer cell metastasis

Abstract

Eukaryotic elongation factor 2 kinase (eEF2K) negative regulates the elongation phase of mRNA translation and hence protein synthesis. Increasing evidence indicates that eEF2K plays an important role in the survival and migration of cancer cells and in tumour progression.

As demonstrated by two-dimensional wound-healing and three-dimensional transwell invasion assays, knocking down or inhibiting eEF2K in cancer cells impairs migration and invasion of cancer cells. Conversely, exogenous expression of eEF2K or knocking down eEF2 (the substrate of eEF2K) accelerates wound healing and invasion.

Importantly, using LC-HDMS^E analysis, we identify 150 proteins whose expression is decreased and 73 proteins which are increased upon knocking down eEF2K in human lung carcinoma cells. Of interest, 34 down-regulated proteins include integrins and other proteins implicated in cell migration, suggesting that inhibiting eEF2K may help prevent cancer cell mobility and metastasis. Interestingly, eEF2K promotes the association of integrin mRNAs with polysomes, providing a mechanism by which eEF2K may enhance their cellular levels. Consistent with this, genetic knock down or pharmacological inhibition of eEF2K reduces the protein expression levels of integrins.

Notably, pharmacological or genetic inhibition of eEF2K almost completely blocked tumour growth and effectively prevented the spread of tumour cells in vivo. High levels of eEF2K expression were associated with invasive carcinoma and metastatic tumours. These data provide the evidence that eEF2K is a new potential therapeutic target for preventing tumour metastasis. This article is protected by copyright. All rights reserved.

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