Peptide nucleic acids targeting the murine beta-globin mRNAs selectively inhibit hemoglobin production in Murine Erythroleukemia (MEL) cells.

In sickle-cell anemia (SCA), HbS appears to be an important therapeutic target, since its polymerization is responsible for sickling of SCA red- blood cells and important adverse clinical parameters. Inhibition of beta- globin might be beneficial, allowing further reduction of sickling properties. Therefore drugs-based methods enabling efficient inhibition of accumulation of this defective globin can be of great interest. In this field of investigation peptide nucleic acids (PNAs) might be of great interest as potent antisense molecules targeting mRNAs. Murine Erythroleukemia (MEL) cells were chosen as experimental model system, in consideration of the fact that they express, under treatment with different inducers, almost adult hemoglobins, being therefore an excellent and reliable cellular “biosensor” for alteration of beta-globin gene expression using, as red-out assay, the simple benzidine-test for Hb accumulation. We designed (R8-GAGGCAGAGGATAGGTCT) an anti-M-βglob-PNA able to hybridize to a region of both mouse βmajor- and βminor-globin mRNAs exhibiting similar predicted secondary structure. This PNA was linked to a polyarginine tail (R8) in order to improve uptake. We found that the Anti-M-βglob-PNA inhibits the erythroid differentiation and Hb production induced in MEL cells by DMSO and HMBA. No effects on cell growth was observed. In addition, the same PNA failed to inhibit the expression of globin genes when administered to control human K562 cells. Our study allow to propose PNAs to down- regulate pathological hemoglobins involved in the onset of several clinical problems, such as the sickle-hemoglobin (HbS) which is responsible for polymerization and the sickling feature of the SCA red- blood cells.