Resumen de BRG1 regulation by miR-155 in human leukemia and lymphoma cell lines

Marta Cuadros Celorrio, V. Sánchez Martín, Antonio Herrera-Merchan, C. Baliñas, J. Martín Padrón, Laura Boyero Corral, P. Peinado, P. P. Medina

• Introduction/purpose BRG1 is a key regulator of leukemia stem cells. Indeed, it has been observed that this type of cells is unable to divide, survive and develop new tumors when BRG1 is down-regulated.

  Materials and methods We assessed BRG1 and miR-155 expression in 23 leukemia cell lines, and two no pathological lymphocyte samples using qPCR. MiR-155 transfection and western blot were used to analyze the relationship between miR-155 and its validated target, BRG1, by measuring protein expression levels. The effect of miR-155 on cell proliferation and prednisolone sensitivity were studied with resazurin assay.

  Results BRG1 expression levels could correlate negatively with miR-155 expression levels, at least in Burkitt’s lymphoma and diffuse large B cell lymphoma (DLBCL) cell lines. To clarify the role of miR-155 in the regulation of BRG1 expression, we administrated miR-155 mimics in different leukemia/lymphoma cell lines. Our results suggest that miR-155 regulate negatively and significantly the BRG1 expression at least in the MOLT4 cell line.

  Conclusion Our study revealed a previously unknown miR-155 heterogeneity that could result in differences in the treatment with miRNAs in our attempt to inhibit BRG1. However, the expression levels of BRG1 and miR-155, before prednisolone treatment were not statistically significantly associated prednisolone sensitive leukemia cells.