Gold Nanoparticles for BCR-ABL1 Gene Silencing: Improving Tyrosine Kinase Inhibitor Efficacy in Chronic Myeloid Leukemia

Introduction of tyrosine kinase inhibitors for chronic myeloid leukemia treatment is associated with a 63% probability of maintaining a complete cytogenetic response, meaning that over 30% patients require an alternative methodology to overcome resistance, tolerance, or side effects. Considering the potential of nanotechnology in cancer treatment and the benefits of a combined therapy with imatinib, a nanoconjugate was designed to achieve BCR-ABL1 gene silencing. Gold nanoparticles were functionalized with a single-stranded DNA oligonucleotide that selectively targets the e14a2 BCR-ABL1 transcript expressed by K562 cells. This gold (Au)-nanoconjugate showed great efficacy in gene silencing that induced a significant increase in cell death. Variation of BCL-2 and BAX protein expression, an increase of caspase-3 activity, and apoptotic bodies in cells treated with the nanoconjugate demonstrate its aptitude for inducing apoptosis on K562 BCR-ABL1-expressing cells. Moreover, the combination of the silencing Au-nanoconjugate with imatinib prompted a decrease of imatinib IC₅₀. This Au-nanoconjugate was also capable of inducing the loss of viability of imatinib-resistant K562 cells. This strategy shows that combination of Au-nanoconjugate and imatinib make K562 cells more vulnerable to chemotherapy and that the Au-nanoconjugate alone may overcome imatinib-resistance mechanisms, thus providing an effective treatment for chronic myeloid leukemia patients who exhibit drug tolerance.