Gold nanoparticles for nanotheranostics in leukemia – Addressing Chronic Myeloid Leukemia

Abstract

Leukemia is a type of cancer that initiates in the bone marrow and results in the unregulated production of immature white blood cells (leukemic cells). The most homogenous subgroup of the disease is chronic myeloid leukemia (CML) accounting for nearly 1.5 million patients worldwide. Virtually all cases harbor the genetic translocation t(9;22)(q34.1;q11.2) resulting in the BCR-ABL1 gene fusion, that encodes for BCR-ABL1 tyrosine kinase. CML treatment success relies on an early diagnosis and the intense research towards developing effective tyrosine kinase inhibitors (TKI). Nanotechnology offers unprecedent advantages to tackle the shortcomings of conventional procedures for the management of CML. Gold nanoparticles (AuNPs) have unique optical properties suitable for ex vivo biosensing applications, but can also function in vivo as nanocarriers in a theranostic approach that links treatment with diagnosis according to patient’s molecular profile. A gold nanoprobe (Au-nanoprobe) colorimetric assay was optimized for the detection of the most frequent BCR-ABL1 isoform (e14a2) and was validated on fully characterized clinical samples. This simple and cheap method enabled the direct detection of e14a2-expressing RNA samples, with accuracy and high specificity. The Au-nanoprobe assay was translated onto a microfluidics chip, resulting in a faster outcome with smaller sample volumes, due to the scale and design of the device. Additionally, a new therapeutic strategy was designed to overcome CML resistance to first line therapy, such as imatinib (IM). BCR-ABL1 gene silencing was effectively achieved in vitro, using AuNPs functionalized with polyethylene glycol and a hairpin-shaped antisense single stranded DNA (ssDNA) oligonucleotide. Furthermore, the nanoconstruct allowed to reduce the dose of IM, when tested in a combined approach, and potentiated a viability decrease of K562 cells resistant to IM. The results of this thesis strongly suggest that AuNPs are a suitable and flexible tool for CML nanotheranostics, improving detection and a personalized treatment strategy.