Reversal effect of bufalin on multidrug resistance in K562/VCR vincristine-resistant leukemia cell line.

Abstract

OBJECTIVE:

To probe insights into the reversal effect of bufalin on vincristine-acquired multidrug resistance (MDR) in human leukemia cell line K562/VCR.

METHODS:

Proliferative inhibition rate and the reversal index (RI) of bufalin were determined by Methyl thiazolyl tetrazolium assay. The uptake of Adriamycin (ADM) in K562/VCR cells, cell cycle and apoptosis rate were determined by flow cytometry (FCM). Cell morphologic changes were observed with Wright-Giemsa staining. The expression of P-glycoprotein (P-gp), multidrug-associated protein-1 (MRP1), Bcl-xL and Bax protein were measured by immunocytochemistry.

RESULTS:

The human leukemia multidrug resistant K562/VCR cells showed no cross-resistance to bufalin. The RIs of bufalin at concentrations of 0.0002, 0.001 and 0.005 μmol/L were 4.85, 6.94 and 14.77, respectively. Preincubation of 0.001 μmol/L bufalin for 2 h could increase intracellular ADM fluorescence intensity to 28.07% (P < 0.05) and down-regulate MRP1 expression simultaneously, but no remarkable effect was found on P-gp protein. Cell cycle analysis indicated increased apoptosis rate and apparent decreased G2/M phase proportion after treatment with bufalin. When exposed to 0.01 μmol/L bufalin, typical morphological changes of apoptosis could be observed. Down-regulation of Bcl-xL and up-regulation of Bax expression in K562/VCR cells could be detected by immunocytochemistry.

CONCLUSION:

Bufalin could partly reverse the MDR of K562/VCR cells, with a possible mechanism of down-regulating MRP1 expression and activating apoptosis pathway by altering Bcl-xL/Bax ratio.

• Authors: Xiaofeng Zhai, Jianying Lu, Ying Wang, Fanfu Fang, Bai Li, Wei Gu
• Journal: Journal of traditional Chinese medicine = Chung i tsa chih ying wen pan (J Tradit Chin Med) Vol. 34 Issue 6 Pg. 678-83 (Dec 2014) ISSN: 0255-2922 [Print] China
• PMID: 25618972 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• ATP Binding Cassette Transporter, Subfamily B
• ATP Binding Cassette Transporter, Subfamily B, Member 1
• Bufanolides
• bcl-2-Associated X Protein
• Vincristine
• bufalin

Topics

• ATP Binding Cassette Transporter, Subfamily B (genetics, metabolism)
• ATP Binding Cassette Transporter, Subfamily B, Member 1 (genetics, metabolism)
• Apoptosis (drug effects)
• Bufanolides (pharmacology)
• Cell Cycle (drug effects)
• Drug Resistance, Multiple
• Drug Resistance, Neoplasm
• Humans
• K562 Cells
• Leukemia (drug therapy, genetics, metabolism, physiopathology)
• Vincristine (pharmacology)
• bcl-2-Associated X Protein (genetics, metabolism)