Short 21-mer double-stranded/small-interfering RNAs (ds/siRNAs) were designed to target bcr-abl
mRNA in
chronic myelogenous leukemia. The ds/siRNAs were transfected into bcr-abl-positive K-562 (derived from
blast crisis chronic myelogenous leukemia), using
lipofectamine. Penetrating of ds/siRNAs into the cells was detected by fluorescent confocal microscopy, using
fluorescein-labeled ds/siRNAs. The cells were treated with mix of three
siRNA sequences (3 x 60 nM) during 6 days with three repetitive transfections. The
siRNA-treatment was accompanied with significant reduction of bcr-abl
mRNA, p210,
protein tyrosine kinase activity and cell proliferation index. Treatment of cells with
Glivec (during 8 days with four repetitive doses, 180 nM single dose) resulted in analogous reduction of cell proliferation activity, stronger suppression of
protein tyrosine kinase activity, and very low reduction of p210.
siRNA-mix and
Glivec did not affect significantly the viability of normal lymphocytes. Microarray analysis of
siRNA- and
Glivec-treated K-562 cells demonstrated that both pathways of bcr-abl suppression were accompanied with overexpression and suppression of many different oncogenes, apoptotic/antiapoptotic and cell proliferation factors. The following genes of interest were found to decrease in relatively equal degree in both
siRNA- and
Glivec-treated cells: Bcd orf1 and orf2 proto-oncogene,
chromatin-specific transcription
elongation factor FACT 140-kDa subunit
mRNA, gene encoding
splicing factor SF1, and
mRNA for
Tec protein tyrosine kinase.
siRNA-mix and
Glivec provoked overexpression of the following common genes: c-jun proto-oncogene,
protein kinase C-alpha, pvt-1 oncogene homologue (myc activator),
interleukin-6, 1-8D gene from
interferon-inducible gene family,
tumor necrosis factor receptor superfamily (10b), and STAT-induced STAT inhibitor.