RESUMEN
<p><b>OBJECTIVE</b>To investigate the effect of short hairpin RNA (shRNA) on mdr1 and GSTpi expression of human multidrug resistant leukemia cell line K562/A02.</p><p><b>METHODS</b>shRNAs were synthesized according to the sequence targeting mdr1 and GSTpi coding region of 79-99nt and 308 approximately 327nt, and cloned into pSilencer 2.1-U6 neo vector. The cloned products, pSilence-mdr1 and pSilence-GSTpi, were transfected into K562/A02 cell line. Expression of mdr1 and GSTpi mRNA was assayed by real time PCR. 50% inhibition concentration (IC(50)) of doxorubicin (ADM) for K562/A02 cell line was determined by MTT method.</p><p><b>RESULTS</b>After transfected with pSilence mdr1, the expression of mdr1 mRNA in K562/A02 cells was reduced by 71.5%, from (2.80 +/- 1.65) x 10(8) copy/microg RNA to (3.90 +/- 2.37) x 10(7) copy/microg RNA(P < 0.01). While the expression of GSTpi mRNA in pSilence-GSTpi transfected K562/A02 cells reduced by 39.8%, from (2.30 +/- 1.14) x 10(5) copy/microg RNA to (5.40 +/- 2.45) x 10(4) copy/microg RNA (P < 0.01). The resistance indexes after transfection were decreased to 8 and 10 respectively as compared to 23 of the mock transfection (P < 0.01).</p><p><b>CONCLUSION</b>The shRNA could effectively reverse the multidrug resistance of K562/A02 cell line.</p>