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Inhibition of leukemia cell proliferation by receptor-mediated uptake of c-myb antisense oligodeoxynucleotides
1Laboratorio Chemioterapia Sperimentale, Istituto Tumori Regina Elena, Rome, Italy.
Abstract:
Exposure of human leukemia HL-60 cells to an oligodeoxynucleotide complementary to an 18-base sequence (codons 2-7) of c-myb-encoded mRNA has previously been shown to result in inhibition of cell proliferation. Because HL-60 cells express high levels of transferrin receptor we adapted a DNA delivery system based on receptor-mediated endocytosis to introduce myb oligomers complexed with a transferrin-polylysine conjugate into those cells. A DNA.RNA duplex resistant to S1 nuclease digestion was detected as early as 12 hr after culture of HL-60 cells in the presence of the myb antisense/transferrin-polylysine complex. Exposure of HL-60 cells to the myb antisense/transferrin-polylysine complex resulted in rapid and profound inhibition of proliferation and loss of cell viability much more pronounced than that occurring in cells exposed to free myb antisense oligodeoxynucleotides. The transferrin-polylysine/myb sense complex or the transferrin-polylysine conjugate alone had no effect on HL-60 cell proliferation and viability. These findings indicate that myb synthetic oligodeoxynucleotides enter efficiently into HL-60 by transferrin receptor-mediated endocytosis and exert a profound biological effect. Such a delivery system could exploit other ligand-receptor interactions for the selective delivery of oncogene-targeted antisense oligodeoxynucleotides.
Insights
Antisense oligodeoxynucleotides targeting the c-myb oncogene were delivered to human leukemia cells using a transferrin receptor-mediated system. This method enhanced delivery and inhibited cell proliferation more effectively than free oligodeoxynucleotides.
Area of Science:
- Molecular Biology
- Cancer Research
- Drug Delivery Systems
Background:
- The c-myb oncogene is implicated in human leukemia cell proliferation.
- HL-60 leukemia cells overexpress transferrin receptors, making them suitable for targeted delivery.
- Antisense oligodeoxynucleotides can inhibit gene expression but require efficient delivery systems.
Purpose of the Study:
- To develop and evaluate a transferrin receptor-mediated endocytosis system for delivering c-myb antisense oligodeoxynucleotides to HL-60 cells.
- To assess the efficacy of this delivery system in inhibiting leukemia cell proliferation and viability.
Main Methods:
- Complexing c-myb antisense oligodeoxynucleotides with a transferrin-polylysine conjugate.
- Utilizing receptor-mediated endocytosis for cellular uptake into HL-60 cells.
- Assessing the formation of DNA.RNA duplexes, cell proliferation, and cell viability.
Main Results:
- The transferrin-polylysine complex efficiently delivered myb antisense oligodeoxynucleotides into HL-60 cells.
- A DNA.RNA duplex, indicative of antisense activity, was detected within 12 hours.
- Significant inhibition of proliferation and loss of cell viability were observed, exceeding that of free oligodeoxynucleotides.
Conclusions:
- Transferrin receptor-mediated endocytosis is an effective strategy for delivering oncogene-targeted antisense oligodeoxynucleotides.
- This targeted delivery system demonstrates potent anti-leukemic effects on HL-60 cells.
- The approach holds promise for selective delivery of antisense therapies for cancer treatment.