MiR-146a Expression Level As a Molecular Marker in Acute Promyleocytic Leukemia

Abstract Abstract 4821 MiR-146a which is located on chromosomes 5 may be involved in normal hemtopoisis and the pathogenesis of several hematopoietic diseases through inhibiting the expression of its targets. Acute promyelocytic leukemia (APL) cell line NB4 was taken as research model to find out whether miR-146a expression was associated to cell differentiation and proliferation. The miR-146a expression level of NB4 cells decreased after ATRA treatment, meanwhile the expression level of its predicted target gene Smad4 increased simultaneously. MiR-146a expression plasmid, no related negative control sequence plasmid and recombined luciferase reporter gene vector containing the miR-146a complementary combined site on Smad4 plasmid were constructed by DNA recombination technical. Both recombined plasmids were transiently co-transfected into 293T cells with control plasmid pRL-TK. The interaction between miR-146a and its predicted target gene Smad4 was confirmed by the relative activities of dual luciferase detection. This interaction relationship was further confirmed by liposome entrapment transfection of miR-146a and its antisense molecular in NB4 cells. The expression level of miR-146a in NB4 cells did no influence on Smad4 gene expression but Smad4 protein expression levels (fig 1). The changes of NB4 cells on biological behaviors were observed by cell morphology, proliferation curve and flow cytometry methods under different miR-146a expression status. The results showed that cell proliferation ratio decreased and cell apoptosis ratio increased after miR-146a expression suppression in NB4 cells. The investigation of miR-146a expression levels in mononuclear cells of APL patients' bone marrow and clinical data were carried out. It was showed that the expression levels of miR-146a were higher in APL patients than normal controls. The expression level of miR-146a was positive correlated with peripheral blood white cell count (fig 2). MiR-146a expression level was negative correlated with Th/Ts ratio among these patients (fig 3). MiR-146a/Smad4 signal pathway is expressed in acute promyelocytic leukemia. The proliferation and apoptosis of the cells are modified by the Smad4 protein expression regulated by miR-146a expression. MiR-146a expression is somewhat associated with acknowledged clinical prognosis factors. It has potential possibility to take miR-146a as prognosis factor. Disclosures: No relevant conflicts of interest to declare.