The Role and Clinical Potentials of Circular RNAs in Prostate Cancer

Advanced approaches of the use of circRNAs as a replacement for cancer therapy

Cancer is a broad name for a group of diseases in which abnormal cells grow out of control and are characterized by their complexity and recurrence. Although there has been progress in cancer therapy with the entry of precision medicine and immunotherapy, cancer incidence rates have increased globally. Non-coding RNAs in the form of circular RNAs (circRNAs) play crucial roles in the pathogenesis, clinical diagnosis, and therapy of different diseases, including cancer. According to recent studies, circRNAs appear to serve as accurate indicators and therapeutic targets for cancer treatment. However, circRNAs are promising candidates for cutting-edge cancer therapy because of their distinctive circular structure, stability, and wide range of capabilities; many challenges persist that decrease the applications of circRNA-based cancer therapeutics. Here, we explore the roles of circRNAs as a replacement for cancer therapy, highlight the main challenges facing circRNA-based cancer therapies, and discuss the key strategies to overcome these challenges to improve advanced innovative therapies based on circRNAs with long-term health effects.

Advanced strategies of targeting circular RNAs as therapeutic approaches in colorectal cancer drug resistance

Colorectal cancer (CRC) stands second in terms of mortality and third among the highest prevalent kinds of cancer globally. CRC prevalence is rising in moderately and poorly developed regions and is greater in economically advanced regions. Despite breakthroughs in targeted therapy, resistance to chemotherapeutics remains a significant challenge in the long-term management of CRC. Circular RNAs (circRNAs) have been involved in growing cancer therapy resistance, particularly in CRC, according to an increasing number of studies in recent years. CircRNAs are one of the novel subclasses of non-coding RNAs, previously thought of as viroid. According to studies, circRNAs have been recommended as biological markers for therapeutic targets and diagnostic and prognostic purposes. That is particularly notable given that the expression of circRNAs has been linked to the hallmarks of CRC since they are responsible for drug resistance in CRC patients; thereby, circRNAs are significant for chemotherapy failure. Moreover, knowledge concerning circRNAs remains relatively unclear despite using all these advanced techniques. Here, in this study, we will go over the most recent published work to highlight the critical roles of circRNAs in CRC development and drug resistance and highlight the main strategies to overcome drug resistance to improve clinical outcomes.

Brain-Derived Exosomal CircRNAs in Plasma Serve as Diagnostic Biomarkers for Acute Ischemic Stroke

Acute ischemic stroke (AIS), commonly known as stroke, is a debilitating condition characterized by the interruption of blood flow to the brain, resulting in tissue damage and neurological deficits. Early diagnosis is crucial for effective intervention and management, as timely treatment can significantly improve patient outcomes. Therefore, novel methods for the early diagnosis of AIS are urgently needed. Several studies have shown that bioactive molecules contained in extracellular vesicles, especially circRNAs, could be ideal markers for the diagnosis of many diseases. However, studies on the effects of exosomes and their circRNAs on the development and prognosis of AIS have not been reported extensively. Therefore, we explored the feasibility of using circRNAs in plasma brain-derived exosomes as biomarkers for AIS. By high-throughput sequencing, we first identified 358 dysregulated circRNAs (including 23 significantly upregulated circRNAs and 335 significantly downregulated circRNAs) in the plasma brain-derived exosomes of the brain infarct patient group compared to those of the noninfarct control group. Five upregulated circRNAs (hsa_circ_0007290, hsa_circ_0049637, hsa_circ_0000607, hsa_circ_0004808, and hsa_circ_0000097) were selected for further validation via Real-Time Quantitative Reverse Transcription PCR (qRT‒PCR) in a larger cohort based on the exclusion criteria of log2FC > 1, p < 0.05 and measurable expression. We found that the expression levels of hsa_circ_0007290, hsa_circ_0049637, hsa_circ_0000607, hsa_circ_0004808 and hsa_circ_0000097 were significantly upregulated in AIS patients and could serve as potential biomarkers for AIS with high specificity and sensitivity. Moreover, the expression levels of hsa_circ_0007290, hsa_circ_0049637, hsa_circ_0000607, hsa_circ_0004808 and hsa_circ_0000097 were also found to be positively correlated with National Institutes of Health Stroke Scale (NISS) and modified Rankin scale (mRS) scores, which indicated that the presence of these circRNAs in plasma brain-derived exosomes could also determine the progression of AIS.

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.

A protein-encoding CCDC7 circular RNA inhibits the progression of prostate cancer by up-regulating FLRT3

Circular RNAs (circRNAs) are a family of endogenous RNAs that have become a focus of biological research in recent years. Emerging evidence has revealed that circRNAs exert biological functions by acting as transcriptional regulators, microRNA sponges, and binding partners with RNA-binding proteins. However, few studies have identified coding circRNAs, which may lead to a hidden repertoire of proteins. In this study, we unexpectedly discovered a protein-encoding circular RNA circCCDC7(15,16,17,18,19) while we were searching for prostate cancer related chimeric RNAs. circCCDC7(15,16,17,18,19) is derived from exon 19 back spliced to exon 15 of the CCDC7 gene. It is significantly downregulated in patients with high Gleason score. Prostate cancer patients with decreased circCCDC7(15,16,17,18,19) expression have a worse prognosis, while linear CCDC7 had no such association. Overexpressed circCCDC7(15,16,17,18,19) inhibited prostate cancer cell migration, invasion, and viability, supporting classification of circCCDC7(15,16,17,18,19) as a bona fide tumor suppressor gene. We provide evidence that its tumor suppressive activity is driven by the protein it encodes, and that circCCDC7(15,16,17,18,19) encodes a secretory protein. Consistently, conditioned media from circCCDC7(15,16,17,18,19) overexpressing cells has the same tumor suppressive activity. We further demonstrate that the tumor suppressive activity of circCCDC7(15,16,17,18,19) is at least partially mediated by FLRT3, whose expression also negatively correlates with Gleason score and clinical prognosis. In conclusion, circCCDC7(15,16,17,18,19) functions as a tumor suppressor in prostate cancer cells through the circCCDC7-180aa secretory protein it encodes, and is a promising therapeutic peptide for prostate cancer.

Liquid biopsy in colorectal cancer

Liquid biopsy refers to a set of pathological samples retrieved from non-solid sources, such as blood, cerebrospinal fluid, urine, and saliva through non-invasive or minimally invasive approaches. In the recent decades, an increasing number of studies have focused on clinical applications and improving technological investigation of liquid biopsy biosources for diagnostic goals particularly in cancer. Materials extracted from these sources and used for medical evaluations include cells like circulating tumor cells (CTCs), tumor-educated platelets (TEPs), cell-free nucleic acids released by cells, such as circulating tumor DNA (ctDNA), cell-free DNA (cfDNA), cell-free RNA (cfRNA), and exosomes. Playing significant roles in the pathogenesis of human malignancies, analysis of these sources can provide easier access to genetic and transcriptomic information of the cancer tissue even better than the conventional tissue biopsy. Notably, they can represent the inter- and intra-tumoral heterogeneity and accordingly, liquid biopsies demonstrate strengths for improving diagnosis in early detection and screening, monitoring and follow-up after therapies, and personalization of therapeutical strategies in various types of human malignancies. In this review, we aim to discuss the roles, functions, and analysis approaches of liquid biopsy sources and their clinical implications in human malignancies with a focus on colorectal cancer.

microRNA-184 in the landscape of human malignancies: a review to roles and clinical significance

MicroRNAs (miRNAs) are a class of non-coding RNAs (ncRNAs) with a short length of 19-22 nucleotides. miRNAs are posttranscriptional regulators of gene expression involved in various biological processes like cell growth, apoptosis, and angiogenesis. miR-184 is a well-studied miRNA, for which most studies report its downregulation in cancer cells and tissues and experiments support its role as a tumor suppressor inhibiting malignant biological behaviors of cancer cells in vitro and in vivo. To exert its functions, miR-184 affects some signaling pathways involved in tumorigenesis like Wnt and β-catenin, and AKT/mTORC1 pathway, oncogenic factors (e.g., c-Myc) or apoptotic proteins, such as Bcl-2. Interestingly, clinical investigations have shown miR-184 with good performance as a prognostic/diagnostic biomarker for various cancers. Additionally, exogenous miR-184 in cell and xenograft animal studies suggest it as a therapeutic anticancer target. In this review, we outline the studies that evaluated the roles of miR-184 in tumorigenesis as well as its clinical significance.

Circular RNAs and inflammation: Epigenetic regulators with diagnostic role

Circular RNAs (circRNAs) are a group of transcripts generally known to be non-coding transcripts, but occasionally producing short peptides. Circ_Ttc3/miR-148a, circ_TLK1/miR-106a-5p, circ_VMA21/miR-9-3p, circ_0068,888/miR-21-5p, circ_VMA21/miR-199a-5p, circ_AFF2/miR-375, circ_0008360/miR-135b-5p and circ-FBXW7/miR-216a-3p are examples of circRNA/miRNA pairs that contribute in the pathogenesis of immune-related conditions. CircRNAs have been found to regulate function of immune system and participate in the pathophysiology of immune-related disorders. In the current study, we searched PubMed and Google Scholar databases until July 2022 with the key words "circRNA" OR "circular RNA" AND "inflammation". Then, we assessed the abstract of retrieved articles to include original articles that assessed contribution of circRNAs in the pathoetiology of inflammation and related disorders. Finally, we went through the main texts of the articles and tabulated the available information. Therefore, the current study summarizes the role of circRNAs in the pathoetiology of sepsis, atherosclerosis, rheumatoid arthritis and osteoarthritis, immune-related cardiovascular, pulmonary, gastrointestinal and nervous system disorders.

microRNA-382 as a tumor suppressor? Roles in tumorigenesis and clinical significance

MicroRNAs (miRNAs) are small single-stranded RNAs belonging to a class of non-coding RNAs with an average length of 18-22 nucleotides. Although not able to encode any protein, miRNAs are vastly studied and found to play role in various human physiologic as well as pathological conditions. A huge number of miRNAs have been identified in human cells whose expression is straightly regulated with crucial biological functions, while this number is constantly increasing. miRNAs are particularly studied in cancers, where they either can act with oncogenic function (oncomiRs) or tumor-suppressors role (referred as tumor-suppressor/oncorepressor miRNAs). miR-382 is a well-studied miRNA, which is revealed to play regulatory roles in physiological processes like osteogenic differentiation, hematopoietic stem cell differentiation and normal hematopoiesis, and liver progenitor cell differentiation. Notably, miR-382 deregulation is reported in pathologic conditions, such as renal fibrosis, muscular dystrophies, Rett syndrome, epidural fibrosis, atrial fibrillation, amelogenesis imperfecta, oxidative stress, human immunodeficiency virus (HIV) replication, and various types of cancers. The majority of oncogenesis studies have claimed miR-382 downregulation in cancers and suppressor impact on malignant phenotype of cancer cells in vitro and in vivo, while a few studies suggest opposite findings. Given the putative role of this miRNA in regulation of oncogenesis, assessment of miR-382 expression is suggested in a several clinical investigations as a prognostic/diagnostic biomarker for cancer patients. In this review, we have an overview to recent studies evaluated the role of miR-382 in oncogenesis as well as its clinical potential.

CircRNA hsa_circ_0001627 aggravates cervical cancer progression through upregulation of FNDC3B and activating PI3K/mTOR signaling pathway

Circular RNAs (CircRNAs) are key regulators in the development and progression of human cancers. However, the biological roles and mechanisms of circRNAs in gastric cancer (GC) remain largely unknown. Analyzing circRNA microarray dataset (GSE102686) and clinical specimens, a novel circRNA termed hsa_circ_0001627, was identified and it was highly expressed in CC cancerous tissues and cells, and was associated with poor clinical outcomes. Functionally, hsa_circ_0001627 silencing impaired the malignant progression of CC cells and the growth of CC xenografts in nude mice. Mechanistically, hsa_circ_0001627 acted as a miR-1225-5p sponge, thus indirectly regulating FNDC3B and leading to the activation of PI3K/mTOR signaling pathway. Collectively, the present study indicates that hsa_circ_0001627 regulates miR-1225-5p/FNDC3B/PI3K/mTOR axis and functions as an oncogene in CC progression, suggesting the potential therapeutic use of hsa_circ_0001627 in CC treatment.

The role of microRNA-185 in the pathogenesis of human diseases: A focus on cancer

MicroRNAs (miRNAs) are a widely-studied class of non-coding RNAs characterized by their short length (18-25 nucleotides). The precise functions of miRNAs are not well-elucidated; however, an increasing number of studies suggest their involvement in various physiologic processes and deregulation in pathologic conditions. miRNA-185 (miR-185) is among the mostly-studied miRNAs in human diseases, which is found to play putative roles in conditions like metabolic disorders, asthma, frailty, schizophrenia, and hepatitis. Notably, many cancer studies report the downregulation of miR-185 in cell lines, tumor tissues, and plasma specimens of patients, while it demonstrates a suppressing role on the malignant properties of cancer cells in vitro and in vivo. Accordingly, miR-185 can be considered a tumor suppressor miRNA in human malignancies, while a few studies also report inconsistent findings. Being suggested as a prognostic/diagnostic biomarker, mi-185 is also found to offer clinical potentials, particularly for early diagnosis and prediction of the prognosis of cancer patients. In this review, we have outlined the studies that have evaluated the functions and clinical significance of miR-185 in different human diseases with a particular focus on cancer.

circGFRA1: A circular RNA with important roles in human carcinogenesis

Circular RNAs (circRNAs) are a type of covalently closed RNA molecules, which are mainly formed by back splicing of a precursor mRNA upstream exon into a downstream exon. Abnormally expressed circRNAs can modulate gene transcription by indirectly interacting with microRNAs (miRNAs). According to the current studies, circGFRA1 has been suggested to be upregulated in various cancers. circGFRA1 (hsa_circ_005239) is a type of cancer-related circRNA, which is predicted to be originated from the GFRA1 on chromosome 10. circGFRA1 can act as a sponge for several miRNAs, including miR-34a, miR-1228, miR-361-5p, miR-149, miR-498, miR-188-3p, miR-3064-5p, miR-449a. Additionally, it can regulate signaling pathways such as TGF-β and PI3K/ AKT. circGFRA1 upregulation has been correlated with patients' poor overall survival in diverse cancers. In the present review, we have summarized the oncogenic effect of circGFRA1 in various cancers according to the adopted criteria from in vitro, in vivo, and clinical research. Moreover, functional enrichment analysis was performed on the circGFRA1 host gene and its protein interaction network to detect gene ontology and related pathways.

Epigenetic and Immunological Features of Bladder Cancer

Bladder cancer (BLCA) is one of the most common types of malignant tumors of the urogenital system in adults. Globally, the incidence of BLCA is more than 500,000 new cases worldwide annually, and every year, the number of registered cases of BLCA increases noticeably. Currently, the diagnosis of BLCA is based on cystoscopy and cytological examination of urine and additional laboratory and instrumental studies. However, cystoscopy is an invasive study, and voided urine cytology has a low level of sensitivity, so there is a clear need to develop more reliable markers and test systems for detecting the disease with high sensitivity and specificity. Human body fluids (urine, serum, and plasma) are known to contain significant amounts of tumorigenic nucleic acids, circulating immune cells and proinflammatory mediators that can serve as noninvasive biomarkers, particularly useful for early cancer detection, follow-up of patients, and personalization of their treatment. The review describes the most significant advances in epigenetics of BLCA.

Prostate Cancer and microRNAs: New insights into Apoptosis

Prostate cancer (PCa) is known as one of the most prevalent malignancies globally and is not yet curable owing to its progressive nature. It has been well documented that Genetic and epigenetic alterations maintain mandatory roles in PCa development. Apoptosis, a form of programmed cell death, has been shown to be involved in a number of physiological processes. Apoptosis disruption is considered as one of the main mechanism involved in lots of pathological conditions, especially malignancy. There is ample of evidence in support of the fact that microRNAs (miRNAs) have crucial roles in several cellular biological processes, including apoptosis. Escaping from apoptosis is a common event in malignancy progression. Emerging evidence revealed miRNAs capabilities to act as apoptotic or anti-apoptotic factors by altering the expression levels of tumor inhibitor or oncogene genes. In the present narrative review, we described in detail how apoptosis dysfunction could be involved in PCa processes and additionally, the mechanisms behind miRNAs affect the apoptosis pathways in PCa. Identifying the mechanisms behind the effects of miRNAs and their targets on apoptosis can provide scientists new targets for PCa treatment.

Comprehensive profile and contrastive analysis of circular RNA expression in cervical squamous carcinoma and adenocarcinoma

Background

Numerous studies have shown circular RNA (circRNA) dysregulation is associated with the pathogenesis of cervical cancer,particularly in individual carcinoma variants. The aim of this study is to investigate and contrastively analyze the expression pattern of circRNAs in cervical squamous carcinoma and adenocarcinoma mediated by human papillomavirus type 16 (HPV-16).

Methods

The expression of circRNAs in cervical squamous carcinoma (SCC), adenocarcinoma (ADC) and adenosquamous carcinoma (ASC) tissues, together with the adjacent normal tissues (ANT), was profiled by high-throughput RNA sequencing (RNA-seq). Bioinformatics analysis and quantitative real time polymerase chain reaction (qRT-PCR) validation of the sequencing data were performed. A network of circRNA-miRNA (microRNA)-mRNA was then constructed according to predicted targets and function of candidate circRNAs.

Results

A total of 11,685 annotated circRNAs were identified in six cervical samples. There were 42 up-regulated and 98 down-regulated circRNAs. 215 circRNAs were up-regulated in SCC but down-regulated circRNAs in ADC, while 50 circRNAs displayed the opposite trend. Function enrichment analysis based on different expressions of circRNAs found that the most enriched pathway in all the three pathologic variants of cervical cancer was the "ubiquitin mediated proteolysis" pathway. Eight key candidate circRNAs derived from this pathway were further validated, and we noticed that several target miRNAs of candidate circRNAs could target the source genes. Based on this we constructed a related competing endogenous RNA (ceRNA) network.

Conclusion

Through a comprehensive interpretation of differentially expressed circRNAs in different pathologic variants of cervical cancer, this study provides new insights into the process of tumor differentiation mediated by HPV. Our results may help to complement the molecular typing and stem cell theory of cervical cancer.

Recent insights into the roles of circular RNAs in human brain development and neurologic diseases

Circular RNAs (circRNAs) are a novel class of non-coding RNAs. They are single-stranded RNA transcripts characterized with a closed loop structure making them resistant to degrading enzymes. Recently, circRNAs have been suggested with regulatory roles in gene expression involved in controlling various biological processes. Notably, they have demonstrated abundance, dynamic expression, back-splicing events, and spatiotemporally regulation in the human brain. Accordingly, they are expected to be involved in brain functions and related diseases. Studies in animals and human brain have revealed differential expression of circRNAs in brain compartments. Interestingly, contributing roles of circRNAs in the regulation of central nervous system (CNS) development have been demonstrated in a number of studies. It has been proposed that circRNAs play role in substantial neurological functions like neurotransmitter-associated tasks, neural cells maturation, and functions of synapses. Furthermore, 3 main pathways have been identified in association with circRNAs's host genes including axon guidance, Wnt signaling, and transforming growth factor beta (TGF-β) signaling pathways, which are known to be involved in substantial functions like migration and differentiation of neurons and specification of axons, and thus play role in brain development. In this review, we have an overview to the biogenesis, biological functions of circRNAs, and particularly their roles in human brain development and the pathogenesis of neurodegenerative diseases including Alzheimer's diseases, multiple sclerosis, Parkinson's disease and brain tumors.

A review on the role of ncRNAs in the pathogenesis of cholangiocarcinoma

Cholangiocarcinoma is a rare tumor but a challenging cancer in terms of pathological changes, clinical manifestations and therapeutic options. Recent studies have provided evidence for participation of non-coding RNAs in the carcinogenic process of cholangiocarcinoma. We demonstrate the role of long non-coding RNAs, microRNAs and circular RNAs in the pathogenesis of cholangiocarcinoma and highlight their significant position as therapeutic targets and biomarkers for this type of cancer. We also list a number of molecular axes comprising these non-coding RNAs that represent potential targets for therapeutic options in cholangiocarcinoma, based on their significant roles in the regulation of cell proliferation, differentiation and apoptosis of these cells.

Signaling pathways governing glioma cancer stem cells behavior

Glioma is the most common malignant brain tumor that develops in the glial tissue. Several studies have identified that glioma cancer stem cells (GCSCs) play important roles in tumor-initiating features in malignant gliomas. GCSCs are a small population in the brain that presents an essential role in the metastasis of glioma cells to other organs. These cells can self-renew and differentiate, which are thought to be involved in the pathogenesis of glioma. Therefore, targeting GCSCs might be a novel strategy for the treatment of glioma. Accumulating evidence revealed that several signaling pathways, including Notch, TGF-β, Wnt, STAT3, AKT, and EGFR mediated GCSC growth, proliferation, migration, and invasion. Besides, non-coding RNAs (ncRNAs), including miRNAs, circular RNAs, and long ncRNAs have been found to play pivotal roles in the regulation of GCSC pathogenesis and drug resistance. Therefore, targeting these pathways could open a new avenue for glioma management. In this review, we summarized critical signaling pathways involved in the stimulation or prevention of GCSCs tumorigenesis and invasiveness.

Role of circular RNAs in retinoblastoma

Retinoblastoma (RB), the most common malignant retinal tumor among children under 3 years old, is lethal if left untreated. Early diagnosis, together with timely and effective treatment, is important to improve retinoblastoma-related outcomes. Circular RNAs (circRNAs), a new class of non-coding RNAs with the capacity to regulate cellular activities, have great potential in retinoblastoma diagnosis and treatment. Recent studies have identified circular RNAs that regulate multiple cellular processes involved in retinoblastoma, including cell viability, proliferation, apoptosis, autophagy, migration, and invasion. Six circular RNAs (circ-FAM158A, circ-DHDDS, circ-E2F3, circ-TRHDE, circ-E2F5, and circ-RNF20) promote disease progression and metastasis in retinoblastoma and function as oncogenic factors. Other circular RNAs, such as circ-TET1, circ-SHPRH, circ-MKLN1, and circ-CUL2, play tumor suppressive roles in retinoblastoma. At present, the studies on the regulatory mechanism of circular RNAs in retinoblastoma are not very clear. The purpose of this review is to summarize recent studies on the functional roles and molecular mechanisms of circular RNAs in retinoblastoma and highlight novel strategies for retinoblastoma diagnosis, prognosis, and treatment.

The emerging roles and potential applications of circular RNAs in ovarian cancer: a comprehensive review

Ovarian cancer (OC) is among the most common human malignancies and the first cause of deaths among gynecologic cancers. Early diagnosis can help improving prognosis in those patients, and accordingly exploring novel molecular mechanisms may lead to find therapeutic targets. Circular RNAs (circRNAs) comprise a group of non-coding RNAs in multicellular organisms, which are identified with characteristic circular structure. CircRNAs have been found with substantial functions in regulating gene expression through interacting with RNA-binding proteins, targeting microRNAs, and transcriptional regulation. They have been found to be involved in regulating several critical processes such as cell growth, and death, organ development, signal transduction, and tumorigenesis. Accordingly, circRNAs have been implicated in a number of human diseases including malignancies. They are particularly reported to contribute to several hallmarks of cancer leading to cancer development and progression, although a number also are described with tumor-suppressor function. In OC, circRNAs are linked to regulation of cell growth, invasiveness, metastasis, angiogenesis, and chemoresistance. Notably, clinical studies also have shown potentials in diagnosis, prediction of prognosis, and therapeutic targets for OC. In this review, I have an overview to the putative mechanisms, and functions of circRNAs in regulating OC pathogenesis in addition to their clinical potentials.

CircRNAs: novel therapeutic targets in multiple myeloma

BACKGROUND

Circular RNA (circRNA) is a type of non-coding RNA that has recently attracted the attention of researchers. Multiple myeloma (MM) is a hematological malignancy with a dismal prognosis that indicates a pressing need for better treatment alternatives, particularly in terms of biological indicators. According to recent research findings, the presence of circRNA is also closely related to the incidence and progression of malignant hemopathy. There have been, however, only a few investigations of circRNA in MM.

MATERIAL AND METHODS

This review will be on the biological properties and functions of circRNA in MM and a discussion of the clinical utility of circRNA in the diagnosis, prognosis, and treatment of MM.

CONCLUSIONS

CircRNA is involved in gene transcription, translation, and epigenetic modification as well as the regulation of cancer cell proliferation, invasion, and metastasis, and hence, promotes or inhibits the occurrence and progression of MM. Therefore, circRNA holds promise as a potential future MM biomarker.

Magnetic Levitation of Personalized Nanoparticle-Protein Corona as an Effective Tool for Cancer Detection

Unprecedented opportunities for early stage cancer detection have recently emerged from the characterization of the personalized protein corona (PC), i.e., the protein cloud that surrounds nanoparticles (NPs) upon exposure to a patients’ bodily fluids. Most of these methods require “direct characterization” of the PC., i.e., they necessitate protein isolation, identification, and quantification. Each of these steps can introduce bias and affect reproducibility and inter-laboratory consistency of experimental data. To fulfill this gap, here we develop a nanoparticle-enabled blood (NEB) test based on the indirect characterization of the personalized PC by magnetic levitation (MagLev). The MagLev NEB test works by analyzing the levitation profiles of PC-coated graphene oxide (GO) NPs that migrate along a magnetic field gradient in a paramagnetic medium. For the test validation, we employed human plasma samples from 15 healthy individuals and 30 oncological patients affected by four cancer types, namely breast cancer, prostate cancer, colorectal cancer, and pancreatic ductal adenocarcinoma (PDAC). Over the last 15 years prostate cancer, colorectal cancer, and PDAC have continuously been the second, third, and fourth leading sites of cancer-related deaths in men, while breast cancer, colorectal cancer, and PDAC are the second, third and fourth leading sites for women. This proof-of-concept investigation shows that the sensitivity and specificity of the MagLev NEB test depend on the cancer type, with the global classification accuracy ranging from 70% for prostate cancer to an impressive 93.3% for PDAC. We also discuss how this tool could benefit from several tunable parameters (e.g., the intensity of magnetic field gradient, NP type, exposure conditions, etc.) that can be modulated to optimize the detection of different cancer types with high sensitivity and specificity.

The Emerging Roles of the β-Secretase BACE1 and the Long Non-coding RNA BACE1-AS in Human Diseases: A Focus on Neurodegenerative Diseases and Cancer

The β-Secretase (BACE1) is widely studied to be particularly involved in amyloid deposition, a process known as the pathogenic pathway in neurodegenerative diseases. Therefore, BACE1 expression is frequently reported to be upregulated in brain samples of the patients with Alzheimer’s disease (AD). BACE1 expression is regulated by BACE1-AS, a long non-coding RNA (lncRNA), which is transcribed in the opposite direction to its locus. BACE1-AS positively regulates the BACE1 expression, and their expression levels are regulated in physiological processes, such as brain and vascular homeostasis, although their roles in the regulation of amyloidogenic process have been studied further. BACE1-AS dysregulation is reported consistent with BACE1 in a number of human diseases, such as AD, Parkinson’s disease (PD), heart failure (HF), and mild cognitive impairment. BACE1 or less BACE1-AS inhibition has shown therapeutic potentials particularly in decreasing manifestations of amyloid-linked neurodegenerative diseases. Here, we have reviewed the role of lncRNA BACE1 and BACE1-AS in a number of human diseases focusing on neurodegenerative disorders, particularly, AD.

The Role of Circular RNAs in the Carcinogenesis of Bladder Cancer

Circular RNAs (circRNAs) are a group of transcripts with enclosed configurations which can regulate gene expression. These transcripts have important roles in normal development and in the pathogenesis of disorders. Recent evidence has supported involvement of circRNAs in the development of bladder cancer. Several circRNAs such as circ_0058063, hsa-circRNA-403658, circPDSS1, circCASC15, circRNA-MYLK, and circRNA_103809 have been upregulated in bladder cancer samples. On the other hand, hsa_circ_0137606, BCRC-3, circFUT8, hsa_circ_001598, circSLC8A1, hsa_circ_0077837, hsa_circ_0004826, and circACVR2A are among downregulated circRNAs in bladder cancer. Numerous circRNAs have diagnostic or prognostic value in bladder cancer. In this review, we aim to outline the latest findings about the role of circRNAs in bladder cancer and introduce circRNAs for further investigations as therapeutic targets.

Oncogenic Roles of Small Nucleolar RNA Host Gene 7 (SNHG7) Long Noncoding RNA in Human Cancers and Potentials

Long noncoding RNAs (lncRNAs) are a class of noncoding transcripts characterized with more than 200 nucleotides of length. Unlike their names, some short open reading frames are recognized for them encoding small proteins. LncRNAs are found to play regulatory roles in essential cellular processes such as cell growth and apoptosis. Therefore, an increasing number of lncRNAs are identified with dysregulation in a wide variety of human cancers. SNHG7 is an lncRNA with upregulation in cancer cells and tissues. It is frequently reported with potency of promoting malignant cell behaviors in vitro and in vivo. Like oncogenic/tumor suppressor lncRNAs, SNHG7 is found to exert its tumorigenic functions through interaction with other biological substances. These include sponging target miRNAs (various numbers are identified), regulation of several signaling pathways, transcription factors, and effector proteins. Importantly, clinical studies demonstrate association between high SNHG7 expression and clinicopathological features in cancerous patients, worse prognosis, and enhanced chemoresistance. In this review, we summarize recent studies in three eras of cell, animal, and human experiments to bold the prognostic, diagnostic, and therapeutic potentials.