Abstract: Objective  To investigate the effect and mechanism of low-frequency ultrasound microbubbles on paclitaxel-induced autophagy in triple negative breast cancer cells.
Methods  MDA-MB-468 cells were divided into control group(treatment),paclitaxel group(6 μg/ml paclitaxel),low-frequency ultrasound group(low-frequency ultrasound+6 μg/ml paclitaxel) and low-frequency ultrasound microbubbles group(low-frequency ultrasound+6 μg/ml paclitaxel+microbubbles),the proliferation,apoptosis,autophagy of MDA-MB-468 cells and the expression of Bcl-2,Bax,Beclin1,LC3Ⅰ and LC3Ⅱ in MDA-MB-468 cells.
Results  Compared with 0μg/ml,1,3,6,12,24μg/ml paclitaxel increased the proliferation inhibition rate of MDA-MB-468 cells(P<0.05).Compared with those in the control group,the proliferation inhibition rate and apoptosis rate of MDA-MB-468 cells,protein expression levels of Bax,Beclin1 and LC3Ⅱ in paclitaxel group were higher(P<0.05),the number of green dots was more,and the protein expression levels of Bcl-2 and LC3 were lower(P<0.05);compared with those in paclitaxel group,the proliferation inhibition rate and apoptosis rate of MDA-MB-468 cells,protein expression levels of Bax,Beclin1 and LC3Ⅱ in low-frequency ultrasound group were higher(P<0.05),the number of green dots was more,and the protein expression levels of Bcl-2 and LC3 were lower(P< 0.05);compared with the those in low-frequency ultrasound group,the proliferation inhibition rate and apoptosis rate of MDA-MB-468 cells,protein expression levels of Bax,Beclin1 and LC3Ⅱ in high-frequency ultrasound microbubbles group were higher(P<0.05),the number of green dots was more,and the protein expression levels of Bcl-2 and LC3 were lower(P<0.05).
Conclusion  Low-frequency ultrasound microbubbles can enhance the apoptosis and autophagy induced by paclitaxel in triple negative breast cancer cells by up-regulating the expression of Bax,Beclin1,LC3Ⅱ protein and down-regulating the expression of Bcl-2 and LC3Ⅰ protein.

Key words: low-frequency ultrasound microbubbles, paclitaxel, triple negative breast cancer, apoptosis, autophagy