[Correlation of high expression of HSP27 to multidrug resistance of leukemia cell line K562/VCR].

Background & Objective: Multidrug resistance (MDR) is a major obstacle preventing effective treatment of leukemia. The mechanisms of MDR in leukemic cells have been broadly explored, but they are still unclear. We used proteomic tools to screen MDR-related proteins in vincristine-resistant leukemia cell line K562/VCR, and analyzed the mechanism of MDR in leukemia.
Methods: Two-dimensional electrophoresis (2-DE) was used to extract total proteins from K562/VCR and K562 cells. The proteins expressed differentially between the two cell lines were identified by matrix-assisted laser desorption/ionization-time of flight-mass spectrometry (MALDI-TOF-MS). The antisense oligonucleotide (ASO) of the protein was transfected into K562/VCR cells; mis-sense oligonucleotide (MSO) of the protein was also transfected as control. The expression of the protein was detected by Western blot. Cell survival was detected by MTT assay. Cell apoptosis was detected by flow cytometry (FCM).
Results: Heat shock protein 27 (HSP27), a differential expression protein between K562/VCR and K562 cells, was identified. When treated with vincristine, the survival rate of K562/VCR cells was significantly lower in HSP27 ASO group than in HSP27 MSO group (P<0.05). The apoptosis rate of K562/VCR cells was significantly higher in HSP27 ASO group than in HSP27 MSO group (16.37% vs. 3.08%, P<0.05).
Conclusion: HSP27 is highly expressed in K562/VCR cells, and the suppression of its expression by HSP27 ASO could enhance chemosensitivity of K562/VCR cells to vincristine.