CircFAM114A2 Promotes Cisplatin Sensitivity via miR-222-3p/P27 and miR-146a-5p/P21 Cascades in Urothelial Carcinoma

CircFAM114A2 Suppresses Cell Proliferation, Migration, and Invasion of Colorectal Cancer Through Sponging miR-647 to Upregulate DAB2IP Expression

BACKGROUND

Increasing evidence had proved that some circular RNA (circRNA) exerted critical roles in tumors progression by functioning as "microRNAs (miRNAs) sponges" to regulate their targeted genes.

METHODS

circFAM114A2 and miR-647 expression was measured in CRC tissues and cells by quantitative real-time polymerase chain reaction (qRT-PCR), and the prognostic value of circFAM114A2 evaluated by Kaplan-Meier survival curve. Subsequently, wounding healing and transwell assays were performed to assess cell proliferation, migration, and invasion. RNA pull-down and dual-luciferase reporter assays were used to confirm the interactions between circFAM114A2, miR-647, and DAB2IP.

RESULTS

CircFAM114A2 was notably downregulated in CRC tissues and cells, and low circFAM114A2 expression indicated the poor prognosis of CRC patients. Next, overexpression of circFAM114A2 suppressed CRC cells proliferation, migration, and invasion in vitro and impede CRC tumor growth in vivo. Mechanically, circFAM114A2 competitively bound to miR-647 and upregulated its target gene DAB2IP expression in CRC cells.

CONCLUSION

Our results indicated that circFAM114A2/miR-647/DAP2IP axis played an important role in CRC progression, suggesting that circFAM114A2 might be a novel therapeutic target in patients with CRC.

Circular RNAs in Cell Cycle Regulation of Cancers

Cancer has been one of the most problematic health issues globally. Typically, all cancers share a common characteristic or cancer hallmark, such as sustaining cell proliferation, evading growth suppressors, and enabling replicative immortality. Indeed, cell cycle regulation in cancer is often found to be dysregulated, leading to an increase in aggressiveness. These dysregulations are partly due to the aberrant cellular signaling pathway. In recent years, circular RNAs (circRNAs) have been widely studied and classified as one of the regulators in various cancers. Numerous studies have reported that circRNAs antagonize or promote cancer progression through the modulation of cell cycle regulators or their associated signaling pathways, directly or indirectly. Mostly, circRNAs are known to act as microRNA (miRNA) sponges. However, they also hold additional mechanisms for regulating cellular activity, including protein binding, RNA-binding protein (RBP) recruitment, and protein translation. This review will discuss the current knowledge of how circRNAs regulate cell cycle-related proteins through the abovementioned mechanisms in different cancers.

Regulation of cisplatin resistance in bladder cancer by epigenetic mechanisms

Bladder cancer is one of the most common malignancies in the world. Cisplatin is one of the most potent and widely used anticancer drugs and has been employed in several malignancies. Cisplatin-based combination chemotherapies have become important adjuvant therapies for bladder cancer patients. Cisplatin-based treatment often results in the development of chemoresistance, leading to therapeutic failure and limiting its application and effectiveness in bladder cancer. To develop improved and more effective cancer therapy, research has been conducted to elucidate the underlying mechanism of cisplatin resistance. Epigenetic modifications have been demonstrated involved in drug resistance to chemotherapy, and epigenetic biomarkers, such as urine tumor DNA methylation assay, have been applied in patients screening or monitoring. Here, we provide a systematic description of epigenetic mechanisms, including DNA methylation, noncoding RNA regulation, m6A modification and posttranslational modifications, related to cisplatin resistance in bladder cancer.

Circular RNA Controls Tumor Occurrence and Development via Cell Cycle Regulation

Circular RNAs (circRNAs) participate in the occurrence and development of various diseases through different mechanisms, such as by acting as a microRNA (miRNA) sponge, interacting with RNA-binding proteins, and regulating gene transcription and protein translation. For example, the abnormal expression of specific circRNAs in tumor cells can alter key regulatory factors and the cell cycle network, resulting in cell cycle disorders and the development and metastasis of tumors. Here, we summarize the mechanisms involved in the circRNA-mediated processes that lead to uncontrolled cell cycle and tumor cell proliferation. Extensive studies investigating the abnormal expression of circRNAs in different cancer types have been conducted. The unique characteristics of circRNAs and their ability to regulate the cell cycle through diverse mechanisms is extremely valuable in tumor diagnosis, treatment, and prognosis. Our review may assist in further understanding the circRNA-mediated regulation of the cell cycle in tumors and provide insights for research on circRNA-based therapeutic strategies and biological diagnosis for cancer.