Clinical Impact and Regulation of the circCAMSAP1/ miR-328-5p/E2F1 Axis in Colorectal Cancer

A Positive Feedback Loop of E2F4-Mediated Activation of MNX1 Regulates Tumour Progression in Colorectal Cancer

Purpose: Colorectal cancer (CRC) is the 3rd most prevalent malignant tumour globally. Although significant strides have been made in diagnosis and treatment, its prognosis at the moment remains unpromising. Therefore, there is an urgent and desperate need to identify novel biomarkers of CRC and evaluate its mechanism of tumourigenesis and development. Methods: JASPAR and RNAinter databases are used to analyze target genes associated with colorectal cancer. Western blotting, q-PCR and immunohistochemistry et, al. were used to detect the level of MNX1 in patients with colorectal cancer, and Chip-PCR was used to detect the targeted binding ability of E2F4 and MNX1. The cells and animal models overexpressed MNX1 and E2F4 were constructed by shRNA transfection. Results: Herein, MNX1 was highly expressed and linked to favourable overall survival curves in colorectal cancer. The functional assay revealed that MNX1 overexpression could promote proliferation, migration, and invasion of CRC cells. Based on the prediction of the JASPAR and RNAinter databases, the transcription factor, E2F4, was bound to the MNX1 promoter region. The Chromatin Immunoprecipitation (ChIP) assay verified the interactions between MNX1 and E2F4 in CRC. Additionally, we found that sh-E2F4 markedly downregulated the MNX1 levels and reduced CRC progression in vivo and in vitro, which reversed MNX1 overexpression. Conclusion: Therefore, our research discovered that E2F4-mediated abnormal MNX1 expression promotes CRC progression and could become a novel diagnostic or therapeutic target of CRC.

Function of circular RNAs in the pathogenesis of colorectal cancer

Circular RNAs (circRNAs) comprise a group of noncoding RNAs with a circular conformation being constructed by either classic spliceosome-mediated or lariat-kind of splicing. They have tissue and temporal specificity and are involved in different biological functions. A vast body of literature has demonstrated critical roles of circRNAs in the formation or progression of neoplasms. Hsa_circ_0066631, hsa_circ_0082096, ciRS-7, circMAT2B, circ_052666, circMBOAT2, circPACRGL and circ_0128846 are among up-regulated circRNAs in CRC. Instead, expression levels of circTADA2A, circ_022743, circ_004452, circ-FBXW7, circ0106714, circFNDC3B and circ_cse1 have been decreased in CRC samples. Finally, expression levels of circRNA-100876, hsa_circ_0002320, circNOL10, circ_0056618, circ_0060745, circ-0004277, hsa_circRNA_102958, circPPP1R12A, hsa_circ_0007534, circ_0079993 and hsa_circ_0005075 can be used for prediction of clinical outcome of patients CRC.

microRNA-939 Promotes the Vitality of Human Breast Cancer Cells via Inhibition of E2F1/P73 Signaling

We assessed miR-939’s role in breast cancer (BC) and its molecular mechanism. PCR was performed to detect miRNA levels. Correlations between miR-939 and patients’ pathological information were analyzed. After transfection of E2F1 plasmid, P73 plasmid, si-E2F1, si-P73, miR-939 mimic or si-miR-939, cell proliferation and apoptosis were measured. The miR-939 target gene was proved by a luciferase assay. Protein and mRNA levels of E2F1 and P73 were detected by immunoblotting and PCR, and corresponding proliferation or apoptosis were assessed. MiR-939 expression was significantly increased in BC and associated with TNM staging, Ki-67 enhancement, and shorter disease-free survival time. In BC clinical samples, E2F1 expression is negatively correlated with miR-939 expressions. Overexpressing miR-939 stimulated growth but suppressed cell apoptosis. Functional analysis indicated E2F1 is the target gene of miR-939, and overexpression of miR-939 significantly downregulated E2F1 and P73. Silencing of E2F1 or P73 significantly promoted MDA-MB-231 cell proliferation and inhibited apoptosis. Overexpression of E2F1 plasmid or P73 plasmid significantly inhibited MDA-MB-231 cell proliferation but induced apoptosis. Transfection of P73 or E2F1 plasmid abolished miR-939’s effects on proliferation and apoptosis. miR-939 promotes breast cancer progression by downregulation of E2F1 to inhibit P73 pathway, thereby promoting proliferation and inhibiting apoptosis.

CircCAMSAP1 promotes hepatocellular carcinoma progression through miR-1294/GRAMD1A pathway

Hepatocellular carcinoma (HCC) is one of the most common cancers with high prevalence and mortality, and it has brought huge economic and health burden for the world. It is urgent to found novel targets for HCC diagnosis and clinical intervention. Circular RNA (circRNA) has been reported to participate in many cancer progressions including HCC, suggesting that circRNA might paly essential role in HCC initiation and progression. Our study aims to found that potential circRNA participates in HCC development and its underlying molecular mechanisms. We obtained three pairs of HCC tissues and its adjacent normal tissues data from GEO DataSets. MTT, cell colony, EdU, wound-healing, transwell invasion and mouse xenograft model assays were used to demonstrate the biological functions of circCAMSAP1 in HCC progression. Furthermore, we conducted bioinformatics analysis, AGO2-RIP, RNA pull-down and luciferase reporter assays to assess the association of circCAMSAP1-miR-1294-GRAMD1A axis in HCC cells. The expression of circCAMSAP1 was up-regulated in HCC tissues compared with its adjacent normal tissues. Up-regulation of circCAMSAP1 promoted HCC biological functions both in vitro and in vivo. The promotive effects of circCAMSAP1 on HCC progression function through miR-1294/GRAMD1A pathway. CircCAMSAP1 was up-regulated in HCC tissues, and circCAMSAP1 up-regulated GRAMD1A expression to promote HCC proliferation, migration and invasion through miR-1294. CircCAMSAP1 might be a potential prognosis and therapeutic target for HCC.

MiR-9-1 Suppresses Cell Proliferation and Promotes Apoptosis by Targeting UHRF1 in Lung Cancer

Lung cancer is listed as the most common reason for cancer-related death all over the world despite diagnostic improvements and the development of chemotherapy and targeted therapies. MicroRNAs control both physiological and pathological processes including development and cancer. A microRNA-9 to 1 (miR-9 to 1) overexpression model in lung cancer cell lines was established and miR-9 to 1 was found to significantly suppress the proliferation rate in lung cancer cell lines, colony formation in vitro, and tumorigenicity in nude mice of A549 cells. Ubiquitin-like containing PHD and RING finger domains 1 (UHRF1) was then identified to direct target of miR-9 to 1. The inhibition of UHRF1 by miR-9 to 1 causes G1 arrest and p15, p16, and p21 were re-expressed in miR-9 to 1 group in mRNA level and protein level. Silence of UHRF1 expression in A549 cells resulted in the similar re-expression of p15, p16, p21 which is similar with miR-9 to 1 infection. Therefore, we concluded that UHRF1 is a new target for miR-9 to 1 to suppress cell proliferation by re-expression of tumor suppressors p15, p16, and p21 mediated by UHRF1.