Abstract P5-03-10: Circulating exosomal microRNA profiling to depict mechanisms of chemotherapy resistance among triple negative breast cancer

Abstract

Abstract Background: Chemotherapeutic resistance leads to high mortality among triple negative breast cancer (TNBC) and underlying mechanisms are poorly understood. Exosomes have been new member of liquid biophsy. MicroRNAs (miRNAs), as the most important inclusions in exosomes, making them ideal candidate biomarkers and therapeutical targets. Methods: We isolated exosomes and analyzed exosome-carried miRNAs signatures in several TNBC cells lines sensitive or resistant to adariamycin, docetaxel or cisplatin. The resistance transfer capacity was determined by flow cytometry after sensitive cells incubated 48 hours with exosomes from drug resistant cells. Locked nucleic acid probes and enzyme-labeled fluorescence (LNA-ELF-FISH) was performed to detect exosomal miRNA molecules transfer. Animal mode was constructed to evaluate treatment feasibility using miRNA modified exosomes. Serum exosomes from 40 TNBC stage IV patients underwent chemotherapy before or after progress disease (PD) status were isolated to analyze miRNA profiling for potential biomarkers identification. Results: We successfully isolated and identified exosomes from several drug sensitive and resistant TNBC cell lines and patients. Exosomal miR-222, miR-4443, miR-100, miR-17, miR-210 were found significantly upregulated from chemotherapy resistance cells. Incubation of exosomes from the resistant cells with the sensitive cells resulted in increasing resistant capacity among sensitive cells. Exosomal miRNA molecules transfer were detected using LNA-ELF-FISH. Transfection of synthesized miRNAs competitors into exosomes increased drug sensitivity in vivo. Exosomal miR-222, miR-4443, miR-100, miR-17, miR-210 were also found upregulated significantly from serums of patients after PD status. These five miRNAs were able to differentiate patients with PD status from those with CR or PR status with at least 89% accuracy. Conclusion: Exosomes from chemotherapy resistant TNBC cells could transfer drug resistance to sensitive cells via exosomal miRNAs. A circulating exosomal microRNA profiling was estabilished for potential biomarkers and therapeutical targets identification. Citation Format: He Y, Tang J. Circulating exosomal microRNA profiling to depict mechanisms of chemotherapy resistance among triple negative breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P5-03-10.