Circular RNA LONP2 regulates proliferation, invasion, and apoptosis of bladder cancer cells by sponging microRNA-584-5p

Therapeutic importance and diagnostic function of circRNAs in urological cancers: from metastasis to drug resistance

Circular RNAs (circRNAs) are a member of non-coding RNAs with no ability in encoding proteins and their aberrant dysregulation is observed in cancers. Their closed-loop structure has increased their stability, and they are reliable biomarkers for cancer diagnosis. Urological cancers have been responsible for high mortality and morbidity worldwide, and developing new strategies in their treatment, especially based on gene therapy, is of importance since these malignant diseases do not respond to conventional therapies. In the current review, three important aims are followed. At the first step, the role of circRNAs in increasing or decreasing the progression of urological cancers is discussed, and the double-edged sword function of them is also highlighted. At the second step, the interaction of circRNAs with molecular targets responsible for urological cancer progression is discussed, and their impact on molecular processes such as apoptosis, autophagy, EMT, and MMPs is highlighted. Finally, the use of circRNAs as biomarkers in the diagnosis and prognosis of urological cancer patients is discussed to translate current findings in the clinic for better treatment of patients. Furthermore, since circRNAs can be transferred to tumor via exosomes and the interactions in tumor microenvironment provided by exosomes such as between macrophages and cancer cells is of importance in cancer progression, a separate section has been devoted to the role of exosomal circRNAs in urological tumors.

Insight into the Role of the miR-584 Family in Human Cancers

Among the non-coding RNAs, the aberrant expression of microRNAs (miRNAs) is well described in the oncology field. It is clear that the altered expression of miRNAs is crucial for a variety of processes such as proliferation, apoptosis, motility, angiogenesis and metastasis insurgence. Considering these aspects, RNA-based therapies and the use of miRNAs as non-invasive biomarkers for early diagnosis are underlined as promising opportunities against cancer death. In the era of precision medicine, significant progress in next-generation sequencing (NGS) techniques has broadened knowledge regarding the miRNAs expression profile in cancer tissues and in the blood of cancer patients. In this scenario, pre-clinical and clinical studies suggested that the members of the miR-584 family, i.e., miR-584-5p and -3p, are prominent players in cancer development and progression. Under some conditions, these miRNAs are under-expressed in cancer tissues acting as tumor suppressors, while in other conditions, they are overexpressed, acting as oncogenes increasing the aggressive behavior of cancer cells. The aim of this review is to provide a comprehensive and up-to-date overview on the expression, upstream genes, molecular targets and signaling pathways influenced by the miR-584 family (i.e., miR-584-3p and -5p) in various human solid and hematological cancers. To achieve this goal, 64 articles on this topic are discussed. Among these articles, 55 are focused on miR-584-5p, and it is outlined how this miRNA could be used in future applications as a potential new therapeutic strategy and diagnostic tool.

Glycolysis in human cancers: Emphasis circRNA/glycolysis axis and nanoparticles in glycolysis regulation in cancer therapy

The metabolism of cancer has been an interesting hallmark and metabolic reprogramming, especially the change from oxidative phosphorylation in mitochondria to glucose metabolism known as glycolysis occurs in cancer. The molecular profile of glycolysis, related molecular pathways and enzymes involved in this mechanism such as hexokinase have been fully understood. The glycolysis inhibition can significantly decrease tumorigenesis. On the other hand, circRNAs are new emerging non-coding RNA (ncRNA) molecules with potential biological functions and aberrant expression in cancer cells which have received high attention in recent years. CircRNAs have a unique covalently closed loop structure which makes them highly stable and reliable biomarkers in cancer. CircRNAs are regulators of molecular mechanisms including glycolysis. The enzymes involved in the glycolysis mechanism such as hexokinase are regulated by circRNAs to modulate tumor progression. Induction of glycolysis by circRNAs can significantly increase proliferation rate of cancer cells given access to energy and enhance metastasis. CircRNAs regulating glycolysis can influence drug resistance in cancers because of theirimpact on malignancy of tumor cells upon glycolysis induction. TRIM44, CDCA3, SKA2 and ROCK1 are among the downstream targets of circRNAs in regulating glycolysis in cancer. Additionally, microRNAs are key regulators of glycolysis mechanism in cancer cells and can affect related molecular pathways and enzymes. CircRNAs sponge miRNAs to regulate glycolysis as a main upstream mediator. Moreover, nanoparticles have been emerged as new tools in tumorigenesis suppression and in addition to drug and gene delivery, then mediate cancer immunotherapy and can be used for vaccine development. The nanoparticles can delivery circRNAs in cancer therapy and they are promising candidates in regulation of glycolysis, its suppression and inhibition of related pathways such as HIF-1α. The stimuli-responsive nanoparticles and ligand-functionalized ones have been developed for selective targeting of glycolysis and cancer cells, and mediating carcinogenesis inhibition.