OBJECTIVETo explore the expression of PXR (Pregnane X receptor) in several malignant hematological cell lines, and to investigate the reversal effect of Gambogic acid (GA) on multi-drug resistance (MDR) of K562/A02 cell line and its reversal mechanism.

METHODSTranscription of PXR was detected by real-time PCR in several malignant hematological cell lines. The growth inhibition rate of K562/A02 in different experimental groups was assayed by MTT method, and the expression of PXR protein was measured by Western blot.

RESULTSPXR gene transcription could be detected in several hematological malignancy cell lines, and it was significantly higher in K562/A02 cell line, compared with the other cell lines used in this experiment. Low-dose GA could enhance cell growth inhibition rate, increasing the effect of chemotherapy, which may be associated with down-regulation of PXR expression. PXR gene transcription and protein expression in GA and DNR+GA groups decreased as compared with control group and the DNR group, suggesting that low-dose GA can down-regulate PXR gene transcription and protein expression.

CONCLUSIONPXR gene transcription can be detected in several hematological malignancy cell line, which is significantly higher in K562/A02 cell line, as compared with the other cell lines used in this experiment. Low-dose GA can enhance cell growth inhibition rate, increasing the effect of chemotherapy, which may be associated with down-regulation of PXR expression.