Exosomes secreted from human colorectal cancer cell lines contain mRNAs, microRNAs and natural antisense RNAs, that can transfer into the human hepatoma HepG2 and lung cancer A549 cell lines

Abstract

Exosomes are microvesicles that are released from various cells into the extracellular space. It has been reported that the components within exosomes vary according to the type of secreted cell. In the present study, we investigated the tetraspanin family proteins CD63, CD9 and CD81 as useful collection markers of exosomes derived from the three colorectal cancer (CRC) cell lines HCT-15, SW480 and WiDr. In addition, we aimed to detect the mRNAs, microRNAs and natural antisense RNAs within the exosomes secreted from the three CRC cell lines. Furthermore, we examined whether exosomes containing their RNAs were transferred into the hepatoma cell line HepG2 and lung cancer cell line A549. CD81 was detected in exosomes secreted from the three CRC cell lines. This result indicates that CD81 can be a collection marker of exosomes derived from the three CRC cell lines. When the RNA species within exosomes derived from the three CRC cell lines were examined, the mRNAs of housekeeping genes such as ACTB and GAPDH, the microRNAs such as miR-21, miR-192 and miR-221, and the natural antisense RNAs of LRRC24, MDM2 and CDKN1A genes, were detected. We discovered their natural antisense RNAs within exosomes for the first time in the present study. Furthermore, PKH67-labeled exosomes derived from the CRC cell lines were taken up into HepG2 and A549 cells. These findings indicate that the intracellular RNAs enclosed within exosomes are secreted to the outside, and exosomes derived from the CRC cell lines are transferred into HepG2 and A549 cells. In conclusion, we reveal that exosomes derived from the CRC cell lines contain mRNAs, microRNAs and natural antisense RNAs, and can be delivered into HepG2 and A549 cells. These findings indicate that exosomal RNAs can shuttle between cells, and may be involved in the regulation of gene expression in recipient cells.

Exosome Uptake through Clathrin-mediated Endocytosis and Macropinocytosis and Mediating miR-21 Delivery

“…Tumor cells secrete exosome-packaging miRNAs, circulating in body fluids (serum, plasma, saliva, urine, and milk), and enter into neighboring and distant cells (15,35). miRNAs, protected in exosomes against degradation, is an important regulator of gene expression at the post-transcriptional level (36,37).…”

The regulation of cancer cell migration by lung cancer cell-derived exosomes through TGF-β and IL-10

“…A number of miRs have been demonstrated to be present in exosomes from various cells (including cancer cells), which serve essential roles in the regulation of tumor cell migration (21)(22)(23)(24)(25)(26)(27). Other miRs may be involved in other steps of tumor development: miR-31, -185, and -34b are involved in melanoma invasion (25).…”

Long Non-coding RNAs: Novel Targets for Nervous System Disease Diagnosis and Therapy

“…Membrane-bound exosomes and microvesicles that can circulate between cells within the brain and between cells in the brain and those in the periphery (and vice versa) are emerging as carriers for lncRNAs [91][92][93]. It has been suggested that these extracellular vehicles carry the bulk of RNA circulating in the periphery, and they are very relevant to disease.…”