<?xml version='1.0' encoding='UTF-8'?><xml><records><record><source-app name="HighWire" version="7.x">Drupal-HighWire</source-app><ref-type name="Journal Article">17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Chen, Li</style></author><author><style face="normal" font="default" size="100%">Wang, Jianmin</style></author><author><style face="normal" font="default" size="100%">Xu, Xiaoping</style></author><author><style face="normal" font="default" size="100%">Gao, Lei</style></author><author><style face="normal" font="default" size="100%">Fei, Xinhong</style></author><author><style face="normal" font="default" size="100%">Lou, Jingwei</style></author><author><style face="normal" font="default" size="100%">Huang, Zhengxia</style></author></authors><secondary-authors></secondary-authors></contributors><titles><title><style face="normal" font="default" size="100%">The Synergistic Inhibitory Effect of STI571 in Combination with Arsenic Trioxide (AS&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt;) on Multidrug-Resistant Leukemic Cells</style></title><secondary-title><style face="normal" font="default" size="100%">Chinese Journal of Clinical Oncology</style></secondary-title></titles><dates><year><style  face="normal" font="default" size="100%">2005</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2005-06-01 00:00:00</style></date></pub-dates></dates><pages><style  face="normal" font="default" size="100%">671-674</style></pages><volume><style face="normal" font="default" size="100%">2</style></volume><issue><style face="normal" font="default" size="100%">3</style></issue><abstract><style  face="normal" font="default" size="100%">OBJECTIVE To study the synergistic effect of STI571, an inhibitor of tyrosine kinase, in combination with arsenic trioxide As2O3 on a multidrug-resistant leukemia cell line expressing bcr-abl.METHODS The cytotoxic effect of STI571 alone or in combination with different concentrations of As2O3 on the bcr-abl and mdr1-positive leukemia cell line, K562-n/VCR, was examined by the MTT method.RESULTS One μmol/L of STI571 alone had no significant cytotoxic effect on K562-n/VCR cells. However the cytotoxic effect increased markedly when combined with As2O3 at concentrations of 10-5, 10-6, 10-7 and 10-8 mol/L. The IC50 of K562-n/VCR cells in As2O3 group was 1.879 mol/L, with Upon addition of STI571, the IC50 decreased to 0.155 μmol/L resulting in a synergistic cytotoxic effect on K562-n/VCR cells that was increased 12.1 times.CONCLUSION A combination of STI571 with As2O3 has a more powerful inhibitory effect on leukemia cells expressing positive bcr-abl and positive mdrl compared to the effect with As2O3 alone.</style></abstract></record></records></xml>