CircRNA VPRBP inhibits tumorigenicity of cervical cancer via miR-93-5p/FRMD6 axis

Circ_0051428 targeting miR-885-3p/MMP2 axis enhances the malignancy of cervical cancer

Circular RNAs (circRNAs) are key regulators of cervical cancer (CC) progression. This study aimed to elucidate the role and mechanism of circ_0051428, a novel circRNA, in CC tumorigenesis. Quantitative real-time polymerase chain reaction and western blotting analyses confirmed that circ_0051428 and matrix metalloprotein-2 (MMP2) were overexpressed in CC, whereas the microRNA miR-885-3p was poorly expressed. After performing a series of in vitro and in vivo experiments, circ_0051428 knockdown was shown to repress CC cell invasion and proliferation in vitro, and hamper tumor formation in vivo. Dual-luciferase reporter and RNA-binding protein immunoprecipitation experiments verified that circ_0051428 interacts with miR-885-3p to regulate the target gene MMP2 of miR-885-3p in CC. In addition, miR-885-3p knockdown offset the anticancer effects of circ_0051428 or MMP2 knockdown on CC cell malignancy. Overall, this study revealed that circ_0051428 executes a tumor-promoting function in CC pathogenesis by modulating the miR-885-3p/MMP2 axis. Our findings provide a novel approach for CC treatment.

Circ_0001589/miR-1248/HMGB1 axis enhances EMT-mediated metastasis and cisplatin resistance in cervical cancer

Cervical cancer is the fourth most common malignant tumors in female worldwide. Cirular RNAs (circRNA) represent a new class of regulatory RNA and play a pivotal role in the carcinogenesis and development of tumors. However, their functions have not been fully elucidated in cervical cancer. In this study, we identified an upregulated circRNA, circ_0001589, both in fresh clinical samples and tissue microarray of cervical cancer. Transwell assay and cell apoptosis assay by flow cytometry demonstrated circ_0001589 promotes epithelial-mesenchymal transition (EMT)-mediated cell migration and invasion, and enhanced cisplatin resistance in vitro. In addition, in nude mice model, circ_0001589 increased the number of lung metastases and recovered xenograft growth from cisplatin treatment in vivo. Mechanistically, RNA pull-down assay, RNA immunoprecipitation, and dual-luciferase reporter assay disclosed that circ_0001589 function as an competing endogenous RNA to sponge miR-1248, which directly target the 3' untranslated region of high mobility group box-B1 (HMGB1). Thereby, circ_0001589 upregulated HMGB1 protein expression and accelerate cervical cancer progression. The rescue experiments also revealed that miR-1248 overexpression or HMGB1 knockdown partially reversed the regulatory functions of circ_0001589 on cell migration, invasion, and cisplatin resistance. In summary, our findings suggest the upregulation of circ_0001589 promoted EMT-mediated cell migration and invasion, and enhanced cisplatin resistance via regulating miR-1248/HMGB1 axis in cervical cancer. These results provided new evidence for understanding the carcinogenesis mechanism and finding new therapeutic target for cervical cancer.

MiRNA-93: a novel signature in human disorders and drug resistance

miRNA-93 is a member of the miR-106b-25 family and is encoded by a gene on chromosome 7q22.1. They play a role in the etiology of various diseases, including cancer, Parkinson's disease, hepatic injury, osteoarthritis, acute myocardial infarction, atherosclerosis, rheumatoid arthritis, and chronic kidney disease. Different studies have found that this miRNA has opposing roles in the context of cancer. Recently, miRNA-93 has been downregulated in breast cancer, gastric cancer, colorectal cancer, pancreatic cancer, bladder cancer, cervical cancer, and renal cancer. However, miRNA-93 is up-regulated in a wide variety of malignancies, such as lung, colorectal, glioma, prostate, osteosarcoma, and hepatocellular carcinoma. The aim of the current review is to provide an overview of miRNA-93's function in cancer disorder progression and non-cancer disorders, with a focus on dysregulated signaling pathways. We also give an overview of this miRNA's function as a biomarker of prognosis in cancer and emphasize how it contributes to drug resistance based on in vivo, in vitro, and human studies. Video Abstract.

Cervical cancer heterogeneity: a constant battle against viruses and drugs

Cervical cancer is the first identified human papillomavirus (HPV) associated cancer and the most promising malignancy to be eliminated. However, the ever-changing virus subtypes and acquired multiple drug resistance continue to induce failure of tumor prevention and treatment. The exploration of cervical cancer heterogeneity is the crucial way to achieve effective prevention and precise treatment. Tumor heterogeneity exists in various aspects including the immune clearance of viruses, tumorigenesis, neoplasm recurrence, metastasis and drug resistance. Tumor development and drug resistance are often driven by potential gene amplification and deletion, not only somatic genomic alterations, but also copy number amplifications, histone modification and DNA methylation. Genomic rearrangements may occur by selection effects from chemotherapy or radiotherapy which exhibits genetic intra-tumor heterogeneity in advanced cervical cancers. The combined application of cervical cancer therapeutic vaccine and immune checkpoint inhibitors has become an effective strategy to address the heterogeneity of treatment. In this review, we will integrate classic and recently updated epidemiological data on vaccination rates, screening rates, incidence and mortality of cervical cancer patients worldwide aiming to understand the current situation of disease prevention and control and identify the direction of urgent efforts. Additionally, we will focus on the tumor environment to summarize the conditions of immune clearance and gene integration after different HPV infections and to explore the genomic factors of tumor heterogeneity. Finally, we will make a thorough inquiry into completed and ongoing phase III clinical trials in cervical cancer and summarize molecular mechanisms of drug resistance among chemotherapy, radiotherapy, biotherapy, and immunotherapy.

Critical Roles of Circular RNA in Tumor Metastasis via Acting as a Sponge of miRNA/isomiR

Circular RNAs (circRNAs), a class of new endogenous non-coding RNAs (ncRNAs), are closely related to the carcinogenic process and play a critical role in tumor metastasis. CircRNAs can lay the foundation for tumor metastasis via promoting tumor angiogenesis, make tumor cells gain the ability of migration and invasion by regulating epithelial-mesenchymal transition (EMT), interact with immune cells, cytokines, chemokines, and other non-cellular components in the tumor microenvironment, damage the normal immune function or escape the immunosuppressive network, and further promote cell survival and metastasis. Herein, based on the characteristics and biological functions of circRNA, we elaborated on the effect of circRNA via circRNA-associated competing endogenous RNA (ceRNA) network by acting as miRNA/isomiR sponges on tumor angiogenesis, cancer cell migration and invasion, and interaction with the tumor microenvironment (TME), then explored the potential interactions across different RNAs, and finally discussed the potential clinical value and application as a promising biomarker. These results provide a theoretical basis for the further application of metastasis-related circRNAs in cancer treatment. In summary, we briefly summarize the diverse roles of a circRNA-associated ceRNA network in cancer metastasis and the potential clinical application, especially the interaction of circRNA and miRNA/isomiR, which may complicate the RNA regulatory network and which will contribute to a novel insight into circRNA in the future.