Abstract
BackgroundColorectal cancer (CRC) is the leading cause of cancer-related death worldwide. Exosome shave emerged as crucial regulators of intercellular communication and that abundant Circular RNAs (circRNAs) are enriched within exosomes. CircRNAs are novel members of noncoding RNAs regulating cancer proliferation and progression. However, the function and regulatory mechanism of cancer-derived exosomal circRNAs in CRC remains unclear.MethodsCRC cells-derived exosomes were characterized using transmission electron microscopy, nanoparticle tracking analysis (NTA) and western blot. CCK-8, wound healing and transwell assays, and flow cytometry assays were conducted to assess whether exosomes would affect the proliferation, metastasis, and apoptosis of CRC cells, respectively. Moreover, we performed the RNA sequencing and RT-qPCR to identify circRNAs in exosome-stimulated CRC cells. Fluorescence in situ hybridization (FISH) assay was used to detect the cellular distribution of circPACRGL. Bioinformatic analyses (StarBase 2.0) were used to pool the miRNA targets of circPACRGL. Luciferase assays were performed to verify the direct interaction. Finally, flow cytometry was used to detect the differentiation of N1-N2 neutrophils.ResultsOur study identified a novel CRC-derived exosomal circRNA, circPACRGL. We found circPACRGL was significantly upregulated in CRC cells after tumor-derived exosomes addition. Moreover, circPACRGL serves as a sponge for miR-142-3p/miR-506-3p to facilitate the transforming growth factor-β1 (TGF-β1) expression. As a result, circPACRGL promoted CRC cell proliferation, migration and invasion, as well as differentiation of N1 to N2 neutrophils via miR-142-3p/miR-506-3p-TGF-β1 axis.ConclusionOur study, the first to reveal that cancer-derived exosomal circPACRGL plays an oncogenic role in CRC proliferation and metastasis, providing mechanistic insights into the roles of circRNAs in CRC progression and a valuable marker for CRC treatment.
Highlights
Colorectal cancer (CRC) is one of the most common malignant tumors with a high risk of metastasis and recurrence worldwide [1, 2]
We found circPACRGL was significantly upregulated in CRC cells after tumor-derived exosomes addition
Our study, the first to reveal that cancer-derived exosomal circPACRGL plays an oncogenic role in CRC proliferation and metastasis, providing mechanistic insights into the roles of circRNAs in CRC progression and a valuable marker for CRC treatment
Summary
Colorectal cancer (CRC) is one of the most common malignant tumors with a high risk of metastasis and recurrence worldwide [1, 2]. Increasing evidence has revealed that cancer-derived exosomes play a key role in tumor cell-to-cell communication by transferring and exchanging oncogenic molecules, including circRNAs, microRNAs, mRNAs, proteins, and lipids, involving in the promotion of tumorigenesis, tumor proliferation, tumor metastasis, angiogenesis, immune escape, and drug resistance [6,7,8]. We supposed that exosomal circRNAs may be a new class of potential biomarkers or therapeutic targets for cancer therapy. The functions and underlying mechanisms of cancer-derived exosomal circRNAs still remain largely unexplored. Exosome shave emerged as crucial regulators of intercellular communication and that abundant Circular RNAs (circRNAs) are enriched within exosomes. CircRNAs are novel members of noncoding RNAs regulating cancer proliferation and progression. The function and regulatory mechanism of cancer-derived exosomal circRNAs in CRC remains unclear
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