Roles of exosomes in cancer chemotherapy resistance, progression, metastasis and immunity, and their clinical applications (Review)

Abstract

Exosomes are a type of vesicle that are secreted by cells, with a diameter of 40-100 nm, and that appear as a cystic shape under an electron microscope. Exosome cargo includes a variety of biologically active substances such as non-coding RNA, lipids and small molecule proteins. Exosomes can be taken up by neighboring cells upon secretion or by distant cells within the circulatory system, affecting gene expression of the recipient cells. The present review discusses the formation and secretion of exosomes, and how they can remodel the tumor microenvironment, enhancing cancer cell chemotherapy resistance and tumor progression. Exosome-mediated induction of tumor metastasis is also highlighted. More importantly, the review discusses the manner in which exosomes can change the metabolism of cancer cells and the immune system, which may help to devise novel therapeutic approaches for cancer treatment. With the development of nanotechnology, exosomes can also be used as biomarkers and for the delivery of chemical drugs, serving as a tool to diagnose and treat cancer.

Natural Products in Preventing Tumor Drug Resistance and Related Signaling Pathways

“…Thus, tumor resistance generation is associated with the reactivation or inhibition of these signaling pathways. The mechanisms of tumor resistance are complex [ 4 ]. Resistance is primarily manifested in the following ways [ 5 ].…”

Cellular Integrin α5β1 and Exosomal ADAM17 Mediate the Binding and Uptake of Exosomes Produced by Colorectal Carcinoma Cells

“…Exosomes are a type of extracellular vesicle (EV) of endocytic origin that are released by virtually all cells in multicellular organisms and carry out important intercellular communication functions through the transfer of their biomolecular cargo, which includes lipids, proteins, nucleic acids and metabolites, between the producing and the recipient/target cells [1]. Exosomes produced by cancer cells have been shown to influence 2 of 18 many processes related to cancer progression and metastasis, such as tumor cell proliferation and invasion, angiogenesis, tumor microenvironment promotion and remodelling, chemotherapy resistance, and immune suppression (recently reviewed in [2][3][4]).…”

Exosomal miRNA-21 from Toxoplasma gondii-infected microglial cells induces the growth of U87 glioma cells by inhibiting tumor suppressor genes

“…The exosomes are known as cell-to-cell communicators that deliver biological contents, including proteins and nucleic acids, from neighboring cells 16 , 17 . The exosomes can influence the tumor-related biological processes, such as anti-apoptosis, angiogenesis, and metastasis within the tumor microenvironment 18 . Especially, microRNAs (miRNAs) are small non-coding RNAs with ~ 22 nucleotides and are important post-transcriptional gene regulators controlling more than 30% of human mRNAs by miRNA-induced silencing complex (miRISC) 19 .…”