Nanosecond pulsed electric fields adjuvant chemotherapy for breast cancer: An in vitro study

Chemotherapeutic resistance and adverse effects induced by chemotherapy are major problems of chemotherapy in breast cancer treatment. Lots of efforts have been put into discovering of better therapy for breast cancer. Nanosecond pulsed electric fields has been reported as an efficient drug-free approach to induce cell apoptosis. In the study, we used nanosecond pulsed electric fields adjuvant to gemcitabine, an anti-cancer drug widely used in clinics, as a novel combined therapy to increase the effects of treatment. Two cell lines were tested in the study. Human breast cancer cell line MCF-7 and MDA-MB-231. Cells were exposed to nsPEFs prior to low concentration of gemcitabine. It was observed that the combined treatment of nsPEF and gemcitabine significantly inhibited growth of both cell lines. The inhibition fraction could achieve 2 times greater than that induced by 0.38uM gemcitabine alone. The prior treatment of nsPEFs could sensitize the cells and thus enhance the effects of chemotherapeutic drugs. Similarly, apoptosis fraction increased significantly by adding nsPEF to the drug treatment. The proportion of early apoptosis could reach over 50% after pulsed plus 0.1ug/mL gemcitabine, which is 2-fold increase compared with gemcitabine alone treated cells. Morphological changes were observed by H&E staining. The results indicate that nsPEF can effectively enhance the inhibition of low concentration gemcitabine in breast cancer.