d Rhamnose β-hederin reverses chemoresistance of breast cancer cells by regulating exosome-mediated resistance transmission.

d Rhamnose β-hederin (DRβ-H), an active component extracted from the traditional Chinese medicinal plant Clematis ganpiniana, has been reported to be effective against breast cancer. Recent studies have also indicated that the isolated exosomes (D/exo) from docetaxel-resistant breast cancer cells MCF-7 (MCF-7/Doc) were associated with resistance transmission by delivering genetic cargo. However, the relevance of D/exo during DRβ-H exposure remains largely unclear. In the present work, exosomes were characterized by morphology and size distribution. We reinforced the significant role of D/exo in spreading chemoresistance from MCF-7/Doc to recipient sensitive cells after absorption and internalization. DRβ-H could reduce the formation and release of D/exo. Next, we demonstrated that DRβ-H was able to reverse docetaxel resistance and that D/exo was responsible for DRβ-H-mediated resistance reversal. We also found that DRβ-H could decrease the expressions of several most abundant miRNAs (miR-16, miR-23a, miR-24, miR-26a, and miR-27a) transported by D/exo. Target gene prediction and pathway analysis showed the involvement of these selected miRNAs in pathways related to treatment failure. Our results suggested that DRβ-H could reduce D/exo secretion from MCF-7/Doc cells and induce the reduction in resistance transmission via D/exo.

Chen WX ，Xu LY ，Qian Q ，He X ，Peng WT ，Fan WQ ，Zhu YL ，Tang JH ，Cheng L ... -  《-》

β-Elemene Reverses Chemoresistance of Breast Cancer Cells by Reducing Resistance Transmission via Exosomes.

Currently, exosomes that act as mediators of intercellular communication are being researched extensively. Our previous studies confirmed that these exosomes contain microRNAs (miRNAs) that could alter chemo-susceptibility, which is partly attributed to the successful intercellular transfer of multidrug resistance (MDR)-specific miRNAs. We also confirmed that β-elemene could influence MDR-related miRNA expression and regulate the expression of the target genes PTEN and Pgp, which may lead to the reversal of the chemoresistant breast cancer (BCA) cells. We are the first to report these findings, and we propose the following logical hypothesis: β-elemene can mediate MDR-related miRNA expression in cells, thereby affecting the exosome contents, reducing chemoresistance transmission via exosomes, and reversing the drug resistance of breast cancer cells. MTT-cytotoxic, miRNA microarray, real-time quantitative PCR, Dual Luciferase Activity Assay, and Western blot analysis were performed to investigate the impact of β-elemene on the expression of chemoresistance specific miRNA and PTEN as well as Pgp in chemoresistant BCA exosomes. Drug resistance can be reversed by β-elemene related to exosomes. There were 104 differentially expressed miRNAs in the exosomes of two chemoresistant BCA cells: adriacin (Adr) - resistant MCF-7 cells (MCF-7/Adr) and docetaxel (Doc) - resistant MCF-7 cells (MCF-7/Doc) that underwent treatment. Of these, 31 miRNAs were correlated with the constant changes in the MDR. The expression of miR-34a and miR-452 can lead to changes in the characteristics of two chemoresistant BCA exosomes: MCF-7/Adr exosomes (A/exo) and MCF-7/Doc exosomes (D/exo). The PTEN expression affected by β-elemene was significantly increased, and the Pgp expression affected by β-elemene was significantly decreased in both cells and exosomes. β-elemene induced a significant increase in the apoptosis rate in both MCF-7/Doc and MCF-7/Adr cells. Drug resistance can be reversed by β-elemene, which can alter the expression of some MDR-related miRNAs, including PTEN and Pgp in MCF-7/Adr and MCF-7/Doc in cells. It can therefore affect the exosome contents and induce the reduction of resistance transmission via exosomes.

Zhang J ，Zhang HD ，Yao YF ，Zhong SL ，Zhao JH ，Tang JH ... -  《-》

D Rhamnose β-Hederin against human breast cancer by reducing tumor-derived exosomes.

Chen WX ，Cheng L ，Pan M ，Qian Q ，Zhu YL ，Xu LY ，Ding Q ... -  《-》

Exosomes from drug-resistant breast cancer cells transmit chemoresistance by a horizontal transfer of microRNAs.

Chen WX ，Liu XM ，Lv MM ，Chen L ，Zhao JH ，Zhong SL ，Ji MH ，Hu Q ，Luo Z ，Wu JZ ，Tang JH ... -  《PLoS One》

Exosomes decrease sensitivity of breast cancer cells to adriamycin by delivering microRNAs.

Mao L ，Li J ，Chen WX ，Cai YQ ，Yu DD ，Zhong SL ，Zhao JH ，Zhou JW ，Tang JH ... -  《-》