High Expression of circ_0001821 Promoted Colorectal Cancer Progression Through miR-600/ISOC1 Axis.

It has been reported that circRNAs play an important regulatory role in the progression of colorectal cancer (CRC). However, the molecular role of circ_0001821 in CRC development is unclear. In this study, we aimed to investigate the regulatory role and molecular mechanisms of circ_0001821 in CRC. Reverse transcription-quantitative PCR and western blot assays were used to detect the expression of circ_0001821, miR-600 and isochorismatase domain containing 1 (ISOC1) in CRC tissues as well as its cell lines. Colony formation assay and EDU assay were used to detect the proliferative capacity of cells. Transwell assay was used to assess cell migration and invasion ability. Flow cytometry was used to analyze cell apoptosis. ELISA was used to measure the glycolytic capacity of cells. Dual-luciferase reporter assay and RNA pull-down assay were used to analyze the relationships between circ_0001821, miR-600 and ISOC1. Animal experimentation was used to validate the functional study of circ_0001821 in vivo. Immunohistochemistry (IHC) of Ki67 staining analysis was conducted to assess tumor growth. Circ_0001821 and ISOC1 were significantly increased in CRC tissues and its cell lines, and miR-600 was significantly decreased in CRC tissues and its cell lines. Silencing circ_0001821 inhibited cell proliferation, migration, invasion and glycolytic capacity, while inducing apoptosis. And it could inhibit tumor growth in vivo. Circ_0001821 could act as a sponge for miR-600 to regulate CRC processes. ISOC1 was identified as a downstream regulator of miR-600, also miR-600 could regulate the expression of ISOC1. In addition, circ_0001821 could regulate ISOC1 expression changes through miR-600. Mechanistically, either miR-600 inhibitor or overexpression of ISOC1 could reverse the effects of knockdown of circ_0001821 on cell biological properties. Circ_0001821 regulated the developmental process of CRC through miR-600/ISOC1 axis.