Background:Eukaryotic translation elongation factor 1A2 (eEF1A2) is a known proto-oncogene. We proposed that stimulation of the eEF1A2 expression in cancer tissues is caused by the loss of miRNA-mediated control.Methods:Impact of miRNAs on eEF1A2 at the mRNA and protein levels was examined by qPCR and western blot, respectively. Dual-luciferase assay was applied to examine the influence of miRNAs on 3′-UTR of EEF1A2. To detect miRNA-binding sites, mutations into the 3′-UTR of EEF1A2 mRNA were introduced by the overlap extension PCR.Results:miR-663 and miR-744 inhibited the expression of luciferase gene attached to the 3′-UTR of EEF1A2 up to 20% and 50%, respectively. In MCF7 cells, overexpression of miR-663 and miR-744 reduced the EEF1A2 mRNA level by 30% and 50%. Analogous effects were also observed at the eEF1A2 protein level. In resveratrol-treated MCF7 cells the upregulation of mir-663 and mir-744 was accompanied by downregulation of EEF1A2 mRNA. Both miRNAs were able to inhibit the proliferation of MCF7 cells.Conclusion:miR-663 and miR-744 mediate inhibition of the proto-oncogene eEF1A2 expression that results in retardation of the MCF7 cancer cells proliferation. Antitumour effect of resveratrol may include stimulation of the miR-663 and miR-744 expression.

Aim. The prostate tumor-inducing oncogene (PTI-1), presumably encoding a truncated form of eukaryotic translation elongation factor 1A1 (eEF1A1), was discovered as a gene overexpressed in prostate tumor samples and absent in normal tissues. The mechanism of PTI-1 oncogenicity remains obscure. Methods. Several bioinformatics methods were applied to analyze the PTI-1 mRNA structure, translation efficiency and coding potential. Results. In silico analysis of 5'UTR of its mRNA suggest that PTI-1 mRNA most probably belongs to the class of templates with low translation efficiency. Additionally, novel open reading frame (ORF) starting with alternati- ve initiation site situated upstream of the main ORF start codon was found. Finally, the peptide that does not resemble eEF1A1 but is partially homologous to relaxin can be synthesized. Conclusions. We suggest that the alternative upstream start codon may initiate synthesis of a peptide (uPTI-1) homologous to relaxin, the hormone shown to promote the prostate cancer progression. uPTI-1 protein may interact with the respective relaxin-specific receptors, suggesting that the tumorigenic outcome of PTI-1 is possibly realized via the relaxin-dependent pathway

Eukaryotic translation elongation factor 1A (eEF1A) exists as two 98 % homologous isoforms eEF1A1 and eEF1A2 that are tissue/development specific and differentially linked to apoptosis/cancerogenesis. A2 is overexpressed in a number of tumors while unusual expression of A1 is observed in injured muscles. To approach a possible mechanism underlying induced changes in the relative amounts of the isoforms we examined the intrinsic stability of the proteins and their mRNAs in human cancer cells. Aim. To estimate half-life of the isoforms of eEF1A at mRNA and protein level in human cancer cells. Methods. To measure mRNA stability the transcriptional block technique was applied, with subsequent analysis of the mRNA level by qPCR. To determine the protein decay rate the translation was blocked by cycloheximide and changes in the protein level were detected by Western blot. Results. Calculation of the protein stability revealed half-life of 72 for eEF1A1 and 95 hours for eEF1A2. Half-life of EEF1A1 and EEF1A2 mRNAs were 3 and 60 hours respectively. Conclusions. Despite similar protein stability, the isoforms of eEF1A dramatically differ in the half-lives of their mRNAs, suggesting that the mRNA decay mechanism is one of the main regulators of eEF1A1/A2 amount in MCF7 cancer cells