Circ_0006174 promotes colorectal cancer progression by sponging microRNA-142-3p and regulating X-linked inhibitor of apoptosis expression

Circ_0006174 Upregulates IGF1R to Enhance Radioresistance and Tumorigenesis in Colorectal Cancer via miR-940 Suppression

Colorectal cancer (CRC) is one of the most common malignancies all over the world. Increasing evidence has revealed that circular RNAs (circRNAs) are involved in the progression of CRC. In this study, we aimed to investigate the role and underlying mechanism of circ_0006174 in the development and radiosensitivity of CRC. Circ_0006174, microRNA-940 (miR-940), and insulin-like growth factor 1 receptor (IGF1R) expression levels were evaluated by real-time quantitative polymerase chain reaction (RT-qPCR). The radiosensitivity of cells also was assessed using colony formation assay. Besides, cell proliferation, apoptosis, migration, and invasion were detected by cell counting kit-8 (CCK-8), flow cytometry, and transwell assays. Dual-luciferase reporter and RNA immunoprecipitation (RIP) assays were performed to verify the relationship between miR-940 and circ_0006174 or IGF1R. IGF1R protein level was examined using western blot. A xenograft tumor model was used to verify the function of circ_0006174 in CRC tumor growth in vivo. Circ_0006174 and IGF1R levels were elevated and miR-940 expression was decreased in CRC tissues and cells. Circ_0006174 knockdown enhanced the radiosensitivity of CRC cells by regulating cell proliferation, apoptosis, migration, and invasion in vitro. In mechanism, circ_0006174 served as a sponge for miR-940 to upregulate IGF1R expression. Moreover, circ_0006174 silencing suppressed CRC growth in vivo. Circ_0006174 boosts radioresistance of CRC cells at least partly through upregulating IGF1R expression by sponging miR-940, providing a novel theoretical basis for CRC therapy.

CircRNA circ_0013339 Regulates the Progression of Colorectal Cancer Through miR-136-5p/SOX9 Axis

BACKGROUND

Colorectal cancer (CRC) is a common gastrointestinal malignancy. Dysregulation of circular RNAs (circRNAs) is associated with the progression of CRC. However, the role of circ_0013339 (hsa_circ_0013339) in CRC is still not clear.

METHODS

The levels of circ_0013339, miR-136-5p, and SRY-box transcription factor 9 (SOX9) in CRC were gauged by quantitative real-time polymerase chain reaction (qRT-PCR). Colony formation and 5-Ethynyl-2'-deoxyuridine (EdU) assays were used to detect cell proliferation. Cell counting kit-8 (CCK8) assay was used to measure cell viability. Western blot assay was performed to examine protein expression. The relationship between miR-136-5p and circ_0013339 or SOX9 was tested by dual-luciferase reporter assay. The effect of sh-circ_0013339 on tumor growth in vivo was examined by xenograft experiments.

RESULTS

Circ_0013339 expression was elevated in CRC tissues and cells, and circ_0013339 knockdown diminished the growth of CRC cells. MiR-136-5p was regulated by circ_0013339. MiR-136-5p deficiency ameliorated the effects of circ_0013339 silencing on CRC cell malignant behaviors. Circ_0013339 modulated SOX9 expression through miR-136-5p. SOX9 addition reversed the effects of miR-136-5p overexpression on CRC cell behaviors. Moreover, silencing of circ_0013339 suppressed the growth of xenograft tumors in vivo.

CONCLUSION

Circ_0013339 regulates the progression of CRC through miR-136-5p-dependent regulation of SOX9, uncovering a novel regulatory mechanism of circ_0013339 in CRC.

circMIRIAF aggravates myocardial ischemia-reperfusion injury via targeting miR-544/WDR12 axis

Exploring and discovering novel circRNAs is one of the ways to develop innovative drugs for the diagnosis and treatment of myocardial ischemia-reperfusion injury (MI/RI). In the work, some dysregulated circRNAs were found by microarray screening analysis in AC16 cells, and hsa_circRNA_104852 named circMIRIAF was screened, which was up-regulated in AC16 cells damaged by hypoxia-reoxygenation injury (H/RI). The comprehensive analysis of ceRNA network revealed the potential relationship of circMIRIAF/miR-544/WDR12. Then, the results of interaction research confirmed that circMIRIAF acted as sponge of miR-544 to positively regulate WDR12 protein expression. Further, the validation results indicate that miR-544 silencing increased the expression of WDR12, and WDR12 activated Notch1 signal to aggravate H/RI of AC16 cells and MI/RI of mice via regulating oxidative stress and inflammation. Furthermore, silencing circMIRIAF caused the decreased circMIRIAF levels and the increased miR-544 levels in cardiomyocytes, while excessive miR-544 inhibited WDR12 expression to alleviate the disorder. On the contrary, excessive circMIRIAF increased WDR12 expression by adsorbing miR-544 to exacerbate H/RI in AC16 cells. In addition, circMIRIAF siRNA reversed the aggravation of H/RI in cells caused by WDR12 overexpression. Overall, circMIRIAF can serve as a drug target or treating MI/RI, and circMIRIAF could sponge miR-544 and enhance WDR12 expression to aggravate MI/RI, which may provide a novel therapeutic strategy for MI/RI treatment.

Highlighting functions of apoptosis and circular RNAs in colorectal cancer

Colorectal cancer (CRC) is known as one of the global problems that endangers the lives of thousands of people every year. Various treatments have been used to deal with this disease, but in some cases, they are not effective. Circular RNAs, as a novel class of noncoding RNAs, have different expression levels and various functions in cancer cells, such as gene regulation through microRNA sponging. They play an important role in various cellular processes, including differentiation, proliferation, invasion, and apoptosis. Changes in the process of apoptosis are closely related to the progression or inhibition of various malignancies. Induction of apoptosis in cancer cells is a promising target for tumor therapy. In this study, circRNAs were investigated as being central to the induction or inhibition of apoptosis in CRC. It is hoped that through targeted changes in the function of these biomolecules, better outcomes will be achieved in cancer treatment. Perhaps better outcomes for cancer treatment can be achieved by using new methods and modifying the expression of these nucleic acids. However, using this method may come with challenges and limitations.

Exosomal circRNAs in cancer: Implications for therapy resistance and biomarkers

Despite the advances in cancer treatment in recent years, the development of resistance to cancer therapy remains the biggest hurdle towards curative cancer treatments. Therefore, investigating the molecular mechanisms underlying cancer therapy resistance is of paramount clinical importance. Circular RNAs (circRNAs), novel members of the noncoding RNA family, are endogenous biomolecules in eukaryotes characterized by a covalently closed loop structure with multiple biological functions. Significantly, circRNAs are abundant and stable in exosomes and can be packaged, secreted and transferred to targeted tumour cells, thereby modulating diverse hallmarks of cancer behaviours, such as proliferation, migration, and immune escape. Notably, a great number of exosomal circRNAs are abnormally expressed during cancer treatment and can mediate cancer therapy resistance through complex mechanisms; therefore, targeting exosomal circRNAs is a promising therapeutic method to reverse therapy resistance. This review aimed to elucidate the mechanisms underlying exosomal circRNAs controlling the resistance of cancer to common therapies, such as chemotherapy, targeted therapy, immunotherapy and radiotherapy, and we also discussed the therapeutic potential of exosomal circRNAs as clinical biomarkers and novel targets in cancer clinical management. We also discussed the prospects and challenges of targeting exosomal circRNAs as a novel therapeutic strategy for reversing cancer therapy resistance.

Establishment of a circular RNA regulatory stemness-related gene pair signature for predicting prognosis and therapeutic response in colorectal cancer

Background

Colorectal cancer (CRC) is a common malignant tumor of the digestive tract with a poor prognosis. Cancer stem cells (CSCs) affect disease outcomes and treatment responses in CRC. We developed a circular RNA (circRNA) regulatory stemness-related gene pair (CRSRGP) signature to predict CRC patient prognosis and treatment effects.

Methods

The circRNA, miRNA, and mRNA expression profiles and clinical information of CRC patients were obtained from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases. CRSRGPs were established based on stemness-related genes in the competing endogenous RNA (ceRNA) network. A CRSRGP signature was generated using the least absolute shrinkage and selection operator (Lasso) and Cox regression analysis of TCGA training set. The prognosis was predicted by generating a nomogram integrating the CRSRGP signature and clinicopathologic features. The model was validated in an external validation set (GSE17536). The antitumor drug sensitivity and immunotherapy responses of CRC patients in the high-risk group (HRG) and low-risk group (LRG) were evaluated by the pRRophetic algorithm and immune checkpoint analysis.

Results

We established an 18-CRSRGP signature to predict the prognosis and treatment responses of CRC patients. In the training and external validation sets, risk scores were used to categorize CRC patients into the HRG and LRG. The Kaplan–Meier analysis showed a poor prognosis for patients in the HRG and that subgroups with different clinical characteristics had significantly different prognoses. A multivariate Cox analysis revealed that the CRSRGP signature was an independent prognostic factor. The nomogram integrating clinical features and the CRSRGP signature efficiently predicted CRC patient prognosis, outperformed the current TNM staging system, and had improved practical clinical value. Anticancer drug sensitivity predictions revealed that the tumors of patients in the HRG were more sensitive to pazopanib, sunitinib, gemcitabine, lapatinib, and cyclopamine. Analysis of immune checkpoint markers demonstrated that patients in the HRG were more likely to benefit from immunotherapy.

Conclusion

An efficient, reliable tool for evaluating CRC patient prognosis and treatment response was established based on the 18-CRSRGP signature and nomogram.

Identification of circRNA_001846 as putative non-small cell lung cancer biomarker

CircRNAs play diverse roles in the regulation of oncogenic processes, yet the roles of these circRNAs in non-small cell lung cancer (NSCLC) remain to be fully clarified. Herein, patterns of circRNA expression in NSCLC tissues and paracancerous tissues were assessed, and the relationships between these circRNAs and NSCLC patient clinical findings were assessed. NSCLC tissues were evaluated using a circRNA microarray approach, with Quantitative real‑time polymerase chain reaction (qPCR) qPCR being used to validate candidate circRNA expression levels in NSCLC patients peripheral blood samples. GEO2R was used to analyze the array data. SPSS23.0, GraphPad Prism, and Sigmaplot were utilized for statistical analyses. Overall, 114 circRNAs that were differentially expressed in NSCLC tissue relative to paracancerous tissue levels were identified, of which 77 and 37 were downregulated and upregulated, respectively. CircRNA_001846 were then chosen based on its differential expression score. Consistent with array findings, serum samples from NSCLC patients exhibited circRNA_001846 upregulation relative to those from healthy individuals. The circRNA_001846 was associated with tumor differentiation, lymph node metastasis, and node metastasis stage. Receiver operating characteristic (ROC) curves analyses revealed that levels of circRNA_001846 in the serum were capable of differentiating between individuals diagnosed with NSCLC and controls at a cut off of 3.9496, yielding respective sensitivity and specificity values of 78.2% and 81.1%, with an area under the curve (AUC) value of 0.872. When combined with carcinoembryonic antigen (CEA), this circRNA achieved an improved AUC value of 0.925. CircRNA_001846 may represent a promising diagnostic biomarker for NSCLC.