Exosomes are vesicle bodies secreted by a variety of living cells, which contain various components such as proteins and RNA. The nano-membrane structure prevalent in the body can participate in material exchange and information exchange between cells, which plays an important role in various physiological and pathological processes.

Biological Function of Exosomes
Exosomes play a series of biological roles by transferring specific molecules to recipient cells. Its biological functions include antigen expression, participation in immune regulation, escape from immune surveillance, escape from apoptosis, and drug resistance.

Application of Exosomes in Breast Cancer Treatment
As a Nano Carrier for the Treatment of Breast Cancer
Adverse reactions of breast cancer chemotherapy and endocrine drug therapy to healthy tissues make the treatment of breast cancer more difficult. Exosomes have high serum stability, low toxicity, easy passage through various barriers, high biocompatibility and low immunogenicity. Based on the above characteristics of exosomes, exosomes have the potential to be used as nanocarriers for drug delivery and can be used for the treatment of breast cancer.

Participate in the Immunotherapy of Breast Cancer
The escape of tumors to the immune system makes the treatment of tumors more difficult. Therefore, activation of immune response based on exosomes has become a new cancer treatment strategy. Tumor-derived exosomes carry tumor antigens, which trigger high-efficiency antigen presentation by antigen-presenting cells, and can be used as a source of tumor antigens to prepare tumor vaccines to activate the immune system, thereby promoting anti-tumor responses.

Exosomes Involve in Drug Resistance of Breast Cancer
At present, postoperative chemotherapy and endocrine drugs play an important role in the treatment of breast cancer, but some patients still have drug resistance, which hinders their treatment. Exosomes participate in drug resistance of breast cancer by participating in the formation of drug resistance mechanism, changing tumor microenvironment, transferring contents, etc.

Change Tumor Microenvironment
Tumor microenvironment participates in drug resistance of breast cancer. Tumor-related fibroblasts enhance the self-renewal ability of tumor stem cells through paracrine exosomes, and up-regulate the expression of ABCB5 in tumor stem cells to promote their resistance to chemotherapy drugs, thus inducing breast cancer chemotherapy resistance.

Transfer miRNA
Exosomes exert a drug resistance by transferring specific miRNAs to sensitive recipient cells. Exosomes, after binding, uptake and internalization, can alter the susceptibility of receptor-sensitive cells by regulating gene expression, signaling pathways, cell cycle distribution, and drug-induced apoptosis.

Summary
Exosomes, as an available and effective source of cellular information, have become a hot research topic in recent years, which can help to diagnose breast cancer early and participate in tumor invasion, progression, metastasis, treatment and drug resistance. Therefore, exosomes will become new targets for prevention and treatment of breast cancer metastasis and drug resistance of breast cancer patients in the future. However, some mechanisms of exosomes have not been confirmed. Although many candidate exosomes biomarkers are suggested for breast cancer diagnosis, it is difficult for them to stay in the experimental stage due to their separation, extraction and purification methods. In the future, exosomes will become a new direction of immunotherapy and gene therapy for breast cancer due to their low immunogenicity as nanocarriers.

Author's Bio: 

Creative Biostructure is an innovative biotechnology company founded in 2005, which provides a comprehensive platform to help client to expand the usage of exosome engineering for a specific diagnostic and therapeutic purpose.