G-quadruplex forming region within WT1 promoter is selectively targeted by daunorubicin and mitoxantrone: A possible mechanism for anti-leukemic effect of drugs.

Wilms tumor 1 (WT1) has long been overexpressed in acute myeloid leukemia and has a prognostic value in its diagnosis. Lately, the formation of G-quadruplexes in oncogenic promoters like (WT1) has been widely investigated since stabilization of these structures leads to transcriptional inhibition of the oncogene. Daunorubicin and mitoxantrone considered as crucial components of almost all standard acute myeloid leukemia induction regimens. Herein we have proposed a probable molecular mechanism of action through which the drugs may stabilize (WT1) promoter G-quadruplexes. Differential pulse voltammetry, circular dichroism, and polyacrylamide gel electrophoresis, electrophoretic mobility shifts assay, polymerase chain reaction (PCR) stop assays, and quantitative RT-PCR were performed in order to better understanding the nature of interactions between the drugs and G-quadruplexes. Data revealed that both drugs had potential to stabilize G-quadruplexes and down-regulate WT1 transcription but daunorubicin exposed more silencing impact. The results illustrated the therapeutic association of these two commercial FDA-approved drugs in (WT1) transcriptional down-regulation. Since (WT1) has known as a transcriptional regulator of at least 137 target genes, so the new data are significant for the development of new approaches to regulating WT1 and other target genes by employing special drugs in cancer treatment.