3rd International Congress on Biomedicine (ICB2019)
The potential role of nanoscale exosomes in cancer
The potential role of nanoscale exosomes in cancer
Seyedeh masoumeh mirtaghi,1,*Shabanali Khodashena,2
1. MSC student of Medical biotechnology, faculty of medical sciences, Mazandaran University of medical sciences 2. Assistant professor of Medical biotechnology, faculty of medical sciences, Mazandaran University of medical sciences.
Introduction: Exosomes are 50_150 nm vesicles. They are part of intracellular communication network which are released to extracellular environment. They can shuttle bioactive molecules including proteins, DNA, mRNA, as well as non-coding RNAs from one cell to another, leading to the exchange of genetic information and reprogramming of the recipient cells.
Most of cells (prokaryote and eukaryote) can secrete exosomes which contain specific biomolecules. In mammalian, exosomes are found in body fluids such as blood, urine, saliva and etc. Because their contents reflect the physiological condition of parent cells and their existence in most biological fluids. Increasing evidence suggests that tumor cells release excessive amount of exosomes, which may influence tumor initiation, growth, progression, metastasis, and drug resistance. In addition, exosomes transfer message from tumor cells to immune cells and stromal cells, contributing to the escape from immune surveillance and the formation of tumor niche.
In this review, we highlight the recent advances in the roles of exosomes in cancer with an emphasis on the potential of exosomes as diagnosis biomarker and therapy target. we also tried to present a definition about exosomes and summarize the role of them in formation and progression of diseases.
Methods: Keywords of exosomes, cancer, diagnosis, are searched in google scholar, PubMed and Scopus and articles were reviewed from 2010 to 2018.
Investigation of biomarkers in reviewed articles have done with technics such as real-time PCR for miRNAs and mass spectroscopy, western blot and flowcytometry for proteins. And the methods used for exosome isolation include ultracentrifugation and the immune-bead isolation.
Results: Accumulating evidence indicates that exosomes play important roles in cancer. Exosomes transfer oncogenic proteins and nucleic acids to modulate the activity of recipient cells and play decisive roles in tumorigenesis, growth, progression, metastasis, and drug resistance.
Normal cells are transformed into cancer cells in the process of tumorigenesis. Exosomes from malignant cells have shown the potential to induce normal cell transformation. For instance, prostate cancer cell-derived exosomes could induce neoplastic transformation of adipose-derived stem cells (ASCs). breast cancer cell-derived exosomes contain precursor microRNAs (pre-miRNAs) associated with RNA-induced silencing complex (RISC)-loading complex proteins, which could induce a rapid and efficient silencing of mRNAs in nontumorigenic epithelial cells, resulting in transcriptome reprogramming and oncogenic transformation.
Exosomes from serum of glioblastoma patients contain EGFRvIII mRNA, which stimulate the proliferation of human glioma cells through a self-promoting way.
Heparanase is an enzyme with elevated level in cancer. Overexpression of heparanase promotes exosome secretion. there are several proteins that may act as potential receptors for exosome uptake, such as Tim1/4 for B cells and ICAM-1 for APCs. they demonstrate that double-stranded DNA is present in exosomes from cancer cells and reflects the mutational status of the originated cells.
In addition, exosomes have been utilized as effective vehicle for drug delivery. Exosomes from MSCs have been tested as the vehicle to package and deliver active drugs such as paclitaxel.
Conclusion: Exosomes are small particles with big roles and are emerging as major players in intercellular communication. Exosomes have been suggested as active transporters for proteins, DNA, mRNA, and non-coding RNAs. The roles of exosomes in cancer have been gradually realized. most of the reports have revealed the various pro-tumor effects of exosomes, which is further supported by the observations that the level of circulating exosomes is increased in cancer patients and correlated with tumor progression
However, the exact mechanisms mediating the complex roles of exosomes in cancer have not yet fully elucidated. Exosomes would be ideal biomarkers for cancer diagnosis and targeted therapy because they closely represent the state of their parental cells and are relatively stable in the circulation and could be easily collected from body fluids.