P-glycoprotein (P-gp), aprognostic
indicator for
chemotherapy failure, is encoded by multidrug resistance gene (MDR1). MDR1
mRNA expression could serve as a guidance for
personalized medicine. However, the traditional PCR process for
mRNA measurement is complicated and cannot realize the real-time detection of
mRNA in living single cells. In this work, optimized
gold nanoparticle-based molecular beacons were employed to determine MDR1
mRNA levels in living
cancer cells. To improve detection sensitivity, ultrasound (US) irradiation was applied to facilitate and enhance cellular uptake of hairpin
DNA-coated
gold nanoparticle (hDAuNP). The US conditions including irradiation power, exposure time, duty cycle, and incubation time were optimized. The slight difference in MDR1 expression manipulated by
siRNA silence could be recognized by US assisted hDAuNP beacons; a 10-fold increase of detection sensitivity was achieved compared with the nonultrasound assistance. Meanwhile, the detection cycle could be shortened from 12 to 2 h. Furthermore, this hDAuNP beacon can serve as an antisense agent to down-regulate P-gp expression and to reverse drug resistance of MCF-7/Adr cells to
doxorubicin. Our results demonstrated that the MDR1 hDAuNP beacon assisted by US irradiation had great potential to predict
chemotherapy sensitivity and to overcome multidrug resistance in
cancer cells and was thus a promising tool for
individualized medicine.