Verification of the role of exosomal microRNA in colorectal tumorigenesis using human colorectal cancer cell lines

Abstract

Exosomes are a group of small membranous vesicles that are shed into the extracellular environment by tumoral or non-tumoral cells and contribute to cellular communication by delivering micro RNAs (miRNAs). In this study, we aimed to evaluate the role of exosomal miRNAs from colorectal cancer cell lines in tumorigenesis, by affecting cancer-associated fibroblasts (CAFs), which are vital constituents of the tumor microenvironment. To analyze the effect of exosomal miRNA on the tumor microenvironment, migration of the monocytic cell line THP-1 was evaluated via Transwell migration assay using CAFs isolated from colon cancer patients. The migration assay was performed with CAFs ± CCL7-blocking antibody and CAFs that were treated with exosomes isolated from colon cancer cell lines. To identify the associated exosomal miRNAs, miRNA sequencing and quantitative reverse transcription polymerase chain reaction were performed. The migration assay revealed that THP-1 migration was decreased in CCL7-blocking antibody-expressing and exosome-treated CAFs. Colon cancer cell lines contained miRNA let-7d in secreted exosomes targeting the chemokine CCL7. Exosomes from colorectal cancer cell lines affected CCL7 secretion from CAFs, possibly via the miRNA let-7d, and interfered with the migration of CCR2+ monocytic THP-1 cells in vitro.

Exosomes derived from colon cancer cells promote tumour progression by affecting the tumour microenvironment

“…SEUMC 2019-12-028). CAFs were isolated from the collected tumour samples o and cultured as previously described 12 .…”

Exosomal microRNAs in colorectal cancer: Overcoming barriers of the metastatic cascade (Review)

“…Exosomal miR-25, miR-130b and miR-425 have been similarly implicated in TAM polarization and C-X-C motif chemokine 12 (CXCL12)/C-X-C motif chemokine receptor 4 (CXCR4)-dependent liver metastasis ( 182 ). On the other hand, CRC cell-derived exosomes have been found to diminish the migration of THP-1 monocytes in vitro via the delivery of let-7d, which can downregulate the chemokine C-C motif chemokine ligand 7 (CCL7) ( 183 ), suggesting that exosomal miRNAs can aid immune evasion by interfering with immune cell chemotaxis. A list of exosomal miRNAs that have been implicated in different steps of the metastatic cascade is presented in Table I .…”

Exosomal‐miR‐522‐3p derived from cancer‐associated fibroblasts accelerates tumor metastasis and angiogenesis via repression bone morphogenetic protein 5 in colorectal cancer

“…4,5 Cancer-associated fibroblasts (CAFs) are a crucial component of the TME that promote tumorigenesis by interacting with cancer cells. 6,7 CAFs act as vital modulators in communication between tumor and stroma in most solid tumors, and they interact with all other cells within the TME and promote tumor progression by secreting various chemokines and cytokines. 8,9 For example, Li et al showed that CAFs were able to increase PD-L1 level in mice cancer cells, leading to an immunosuppression microenvironment by containing CXCL5.…”

“…The tumor microenvironment (TME) refers to the surrounding area of tumor growth, which has been shown to play a key role in regulating tumor progression 4,5 . Cancer‐associated fibroblasts (CAFs) are a crucial component of the TME that promote tumorigenesis by interacting with cancer cells 6,7 . CAFs act as vital modulators in communication between tumor and stroma in most solid tumors, and they interact with all other cells within the TME and promote tumor progression by secreting various chemokines and cytokines 8,9 .…”