Circ_0060967 contributes to colorectal cancer progression by sponging miR-1184 to up-regulate SRC proto-oncogene

Roles of circRNAs in the progression of colorectal cancer: novel strategies for detection and therapy

Endogenous noncoding RNAs with a covalently closed loop are known as circular RNAs (circRNAs). Recently, published works have revealed that circRNAs, which act as microRNA sponges, are critical for the biological behavior of several kinds of malignancies, including tumor cell proliferation, apoptosis, invasion, and metastasis. Additionally, there is a significant correlation between circRNAs and tumor resistance, stage, prognosis, and size. At present, colorectal cancer (CRC) is one of the most serious malignant tumors for human health. CircRNAs could represent potential targets to use in the prevention, diagnosis, and therapy of CRC, according to many studies. To fully comprehend the role of circRNAs in the incidence and progression of CRC, this review outlines the regulatory role and mechanisms of circRNAs in CRC and assesses their potential relevance as diagnostic and treatment possibilities for CRC. Our goal is to offer meaningful biological information for clinical evaluation and decision-making process for CRC treatment.

CircXRN2 accelerates colorectal cancer progression through regulating miR-149-5p/MACC1 axis and EMT

In China, there has been a persistent upward trend in the incidence and mortality rates of colorectal cancer (CRC), with CRC ranking second in incidence and fifth in mortality among all malignant tumors. Although circular RNAs (circRNAs) have been implicated in the progression of various cancers, their specific role in CRC progression remains largely unexplored. The objective of this study was to elucidate the role and underlying mechanisms of circXRN2 in CRC. Differential expression of circXRN2 was identified through whole transcriptome sequencing. The expression levels of circXRN2 and miR-149-5p were quantified in CRC tissues, corresponding adjacent normal tissues, and CRC cell lines using quantitative reverse transcription-polymerase chain reaction (qRT-PCR). The stability of circXRN2 was confirmed through RNase R and actinomycin D experiments. The binding interaction between circXRN2 and miR-149-5p was validated through RNA pull-down, RNA immunoprecipitation, and dual-luciferase assays. The biological functions of circXRN2 were assessed through a battery of in vitro experiments, including the CCK-8 assay, EdU assay, scratch assay, Transwell assay, and flow cytometry assay. Additionally, in vivo experiments involving a tumor transplantation model and a liver-lung metastasis model were conducted. The influence of circXRN2 on the expression of epithelial-mesenchymal transition (EMT)-related genes was determined via Western blotting analysis. In CRC tissues and cells, there was an upregulation in the expression levels of both circXRN2 and ENC1, while miR-149-5p exhibited a downregulation in its expression. The overexpression of circXRN2 was found to enhance tumor proliferation and metastasis, as evidenced by results from both in vitro and in vivo experiments. Functionally, circXRN2 exerted its antitumor effect by suppressing cell proliferation, migration, and invasion while also promoting apoptosis. Mechanistically, the dysregulated expression of circXRN2 had an impact on the expression of proteins within the EMT signaling pathway. Our results demonstrated that circXRN2 promoted the proliferation and metastasis of CRC cells through the miR-149-5p/ENC1/EMT axis, suggesting that circXRN2 might serve as a potential therapeutic target and novel biomarker in the progression of CRC.

m6A-modified circ_0124554 promotes colorectal cancer progression and radioresistance through the miR-1184/LASP1 pathway

BACKGROUND

Circular RNAs (circRNAs) are believed to regulate the progression of various cancers including colorectal cancer (CRC). However, the role and mechanism of circ_0124554 in regulating the sensitivity of CRC to radiation remain unknown.

METHODS

The RNA levels of circ_0124554, LIM and SH3 protein 1 (LASP1), and methyltransferase 3, N6-adenosine-methyltransferase complex catalytic subunit (METTL3) were detected by quantitative real-time polymerase chain reaction. Protein expression was checked by western blot. Cell proliferation, apoptosis, migration, and invasion were investigated by 5-Ethynyl-2'-deoxyuridine (EdU) assay, flow cytometry analysis, and transwell assay, respectively. The sensitivity of CRC cells to radiation was analyzed by cell colony formation assay. Xenograft mouse model assay was conducted to disclose the role of circ_0001023 in the sensitivity of tumors to radiation in vivo. The binding relationships among circ_0124554, miR-1184 and LASP1 were confirmed by a dual-luciferase reporter assay. m6A RNA immunoprecipitation assay was performed to identify the association of METTL3 with circ_0124554.

RESULTS

Circ_0124554 expression was upregulated in CRC tissues and cells in comparison with normal colorectal tissues and cells. Circ_0124554 knockdown inhibited proliferation, migration and invasion and promoted apoptosis and radiosensitivity of CRC cells. Moreover, circ_0124554 depletion inhibited tumor formation and improved radiosensitivity in vivo. MiR-1184 was identified as a target miRNA of circ_0124554 and targeted LASP1. Additionally, LASP1 overexpression rescued circ_0124554 knockdown-mediated effects in CRC cells. METTL3 mediated m6A methylation of circ_0124554. Further, circ_0124554 overexpression attenuated METTL3 depletion-induced effects in CRC cells.

CONCLUSION

m6A-modified circ_0124554 promoted CRC progression and radioresistance by inducing LASP1 expression through interaction with miR-1184.