Reversal Effects of Low-frequency Pulsed Electrical Field on Multidrug Resistance of MCF-7/ADR to HHT and VCR

Abstract: In order to explore the reversal effect and mechanism of low-frequency pulsed electrical field (LF-PEF) on multidrug resistance (MDR) of MCF-7/ADR， MTT analysis was used to detect resistance factor (RF) and reversal index (RI). The accumulation and efflux of DiOC₂(3) were studied by fluorescence microscopy. The results showed that LF-PEF could reverse the MDR under the condition which not influence the growth of MCF-7/ADR. RI of HHT was between 1.429-1.848 while RI of VCR was between 1.473-2.090. The sensitivity of MCF-7/ADR to HHT and VCR were enhanced by 45 min exposure to LF-PEF best and the next was 30 min exposure. 45 min exposure to LF-PEF increased the accumulation of intracellular DiOC₂(3) while 30 min exposure inhibited P-gp-dependent efflux of DiOC₂(3). So promoting drug accumulation and inhibiting drug efflux may be one of reversal mechanism of LF-PEF on MDR.

CSTR: 32200.14.cjcb.2007.05.0024