<p><b>OBJECTIVE</b>To explore whether the constructed vector of short haprin in vivo can induce
human glioma cell line BT325 to produce
RNAi duplexes and reverse the expression of MDR1
gene.</p><p><b>
METHODS</b>Three 62nt
oligonucleotide fragments (
shRNA) were constructed according to
GenBank MDR1 sequence and were cloned to the
retrovirus-delivered vectors. After transfected these vectors directly into the
human malignant glioma BT325
cells by lipofectamine 2000 with enhanced green
fluorescence protein (EGFP) co-transfecting, the MDR1
gene silence effects were detected by the changing level of
mRNA and
P-glycoprotein including
real time PCR (RT-PCR),
Northern blot and
Western blot analysis. To assess the
multidrug resistance against
adriamycin (ADR) and VCR,
cell proliferation assays were performed by
cell counting kit-8.</p><p><b>RESULTS</b>The
RNAi plasmid vectors were constructed successfully. RT-PCR showed MDR1
mRNA was significantly reduced (P < 0.05).
Northern blot analysis showed that the
gene silence became most intense at 48 hours after
transfection.
Western blot analysis demonstrated that P-gp expression was reduced at different
time to 12.9%, 30.3% and 4.8%, respectively. The chemosensitivity assays indicated that the transfected
cells showed an enhanced
sensitivity to ADR and VCR. Based on the value of IC(50), BT325
cells had significantly increased
sensitivity to the
drugs.</p><p><b>CONCLUSION</b>The sequence specific
RNAi can inhibit MDR1
mRNA and P-gp expression in the
glioma cell line. It may reverse
multidrug resistance phenotype, therefore, may provide promising
therapeutic modalities in the
treatment of
human glioma.</p>