siRNA-mediated BCR-ABL silencing in primary chronic myeloid leukemia cells using lipopolymers

Area of Science:

• Biochemistry and Molecular Biology
• Nanomedicine and Drug Delivery
• Hematology and Oncology

Background:

• Chronic myeloid leukemia (CML) treatment faces challenges with drug resistance to tyrosine kinase inhibitors.
• Alternative therapeutic strategies are needed to target the primary CML oncogene, BCR-ABL.
• RNA interference (RNAi) using small interfering RNA (siRNA) presents a promising gene-silencing approach.

Purpose of the Study:

• To investigate novel non-viral polymeric delivery systems for siRNA targeting BCR-ABL in CML.
• To evaluate the efficacy of lipopolymers derived from low molecular weight polyethyleneimine (PEI) substituted with lipids (linoleic acid, α-linolenic acid, cholesterol) for siRNA delivery.
• To assess the therapeutic potential of these lipopolymers in primary CML patient samples.

Main Methods:

• Synthesis and characterization of lipopolymers composed of PEI and lipid substituents (linoleic acid, α-linolenic acid, cholesterol).
• In vitro evaluation of siRNA delivery efficiency and cellular uptake in CML cell lines (K562) and primary CML patient cells.
• Quantification of BCR-ABL mRNA expression and assessment of colony formation inhibition following siRNA treatment.

Main Results:

• Lipopolymers demonstrated effective siRNA internalization into primary CML cells, comparable to K562 cell lines.
• Specific lipopolymer formulations (PEI-αLA, PEI-Chol, PEI-LA) significantly reduced BCR-ABL mRNA expression (17-45%) and inhibited colony formation (24-41%) in mononuclear cells.
• BCR-ABL siRNA showed notable efficacy in CD34+ cells, and combination therapy with imatinib (IM) further decreased colony formation in some samples, indicating patient-specific responses.

Conclusions:

• Lipopolymer-mediated siRNA delivery is a viable strategy for targeting BCR-ABL in CML, even in primary patient cells.
• The study highlights the potential of low-dose BCR-ABL siRNA combined with lipopolymers to reduce CML cell survival and proliferation.
• Further investigation with larger patient cohorts is warranted to identify optimal siRNA carriers and understand patient-to-patient variability in therapeutic response.