Background: Myc (c-Myc) alone activates the embryonic stem cell-like transcriptional module in
both normal and transformed cells. Its dysregulation might lead to increased cancer stem cells (CSCs) population
in some tumor cells.
Objective: In order to investigate the potential of Myc decoy oligodeoxynucleotides for differentiation therapy,
mouse embryonic stem cells (mESCs) were used in this study as a model of CSCs. To our best of knowledge
this is the first report outlining the application of Myc decoy in transcription factor decoy “TFD” strategy for
inducing differentiation in mESCs.
Methods: A 20-mer double-stranded Myc transcription factor decoy and scrambled oligodeoxynucleotides
(ODNs) were designed, analyzed by electrophoretic mobility shift (EMSA) assay and transfected into the
mESCs under 2 inhibitors (2i) condition. Further investigations were carried out using fluorescence and confocal
microscopy, cell proliferation and apoptosis analysis, alkaline phosphatase and embryoid body formation
assay, real-time PCR and western blotting.
Results: EMSA data showed that Myc decoy ODNs bound specifically to c-Myc protein. They were found to be
localized in both cytoplasm and nucleus of mESCs. Our results revealed the potential capability of Myc decoy
ODNs to decrease cell viability by (16.1±2%), to increase the number of cells arrested in G0/G1 phases
and apoptosis by (14.2±3.1%) and (12.1±3.2%), respectively regarding the controls. Myc decoy could also
modulate differentiation in mESCs despite the presence of 2i/LIF in our medium the presence of 2i/LIF in our
Conclusion: The optimized Myc decoy ODNs approach might be considered as a promising alternative strategy
for differentiation therapy investigations.