Function and mechanism of TRIM22 targeting eIF4E in the process of NB4 cells differentiation / 国际肿瘤学杂志

ABSTRACT

Objective To investigate the function of tripartite motif protein 22 (TRIM22) and the interaction with eukaryotic translation initiation factor-4E (eIF4E) in the differentiation of NB4 cells, one kind of acute promyelocytic leukemia cells, which elucidates the mechanism of TRIM22 targeting to regulate eIF4E.Methods The model of NB4 cells inducing differentiation was established in vitro.The expression changes of gene and protein of TRIM22 and eIF4E were detected by using quantitative real-time polymerase chain reaction (qRT-PCR) and Western blotting.In addition, the effect on cell function and protein expression level of eIF4E after adopting electroporation technology to depress or over-express TRIM22 was detected by CCK-8 and flow cytometry.Finally, the interaction of TRIM22 and eIF4E was verified by using co-immunoprecipitation (CO-IP).Results The mRNA relative expression level of TRIM22 was gradually increasing from 1.01±0.15 to 30.98±2.79 (F=280.700, P=0.000), and the protein relative expression level was gradually increasing from 0.22±0.03 to 0.51±0.05 (F=51.430, P=0.000) after the all-trans-retinoic acid (ATRA) induction for NB4 cell.However, the mRNA relative expression level of eIF4E was gradually decreasing from 1.01±0.09 to 0.47±0.06 (F=20.520, P=0.000), with the same trend, the protein relative expression level was gradually decreasing from 0.97±0.02 to 0.64±0.09 (F=14.700, P=0.001).The expression level of PE-CD11b in the TRIM22 over-expression group with ATRA detected by flow cytometry [(78.80±2.00)%] was higher than that in the transfection group of empty vetor with ATRA [(58.70±2.70)%] (t=9.535, P=0.000) and the cotransfection group with ATRA [(61.60±3.80)%] (t=8.187, P=0.000).Meanwhile, the protein level of eIF4E changed reversely after over-expressing the gene level of TRIM22 (t=4.985, P=0.007).The CO-IP experiment was used to verify the interaction of TRIM22 and eIF4E.ConclusionTRIM22 is able to promote the cell differentiation during the process of NB4 cells differentiation.Furthermore, eIF4E is a target of TRIM22 for binding with, which plays an important role in depressing the expression of eIF4E.