The Role of Circular RNAs in Keratinocyte Carcinomas

Abstract

Keratinocyte carcinomas (KC) include basal cell carcinomas (BCC) and cutaneous squamous cell carcinomas (cSCC) and represents the most common cancer in Europe and North America. Both entities are characterized by a very high mutational burden, mainly UV signature mutations. Predominately mutated genes in BCC belong to the sonic hedgehog pathway, whereas, in cSCC, TP53, CDKN2A, NOTCH1/2 and others are most frequently mutated. In addition, the dysregulation of factors associated with epithelial to mesenchymal transition (EMT) was shown in invasive cSCC. The expression of factors associated with tumorigenesis can be controlled in several ways and include non-coding RNA molecules, such as micro RNAs (miRNA) long noncoding RNAs (lncRNA) and circular RNAs (circRNA). To update findings on circRNA in KC, we reviewed 13 papers published since 2016, identified in a PubMed search. In both BCC and cSCC, numerous circRNAs were identified that were differently expressed compared to healthy skin. Some of them were shown to target miRNAs that are also dysregulated in KC. Moreover, some studies confirmed the biological functions of individual circRNAs involved in cancer development. Thus, circRNAs may be used as biomarkers of disease and disease progression and represent potential targets of new therapeutic approaches for KC.

Curcuminoids as Modulators of EMT in Invasive Cancers: A Review of Molecular Targets With the Contribution of Malignant Mesothelioma Studies

“…MicroRNAs (miRNAs), with 22-24 nucleotides, presently represent a part of ncRNAs divided in two groups based on their base length, small ncRNAs with fewer than 200 nucleotides, and long forms (lncRNAs) with diverse sizes ranging from 200 to more than a thousand nucleotides. More recently, circular RNAs (circRNAs) were shown to proceed differently as they prevent the inhibitory effect of miRNAs on gene expression by binding to their complementary sequences (Meyer et al, 2021). This growing, rapidly evolving field of research and its relationships with EMT in cancer have been recently reviewed (Hussen et al, 2021), and the role of the dysregulated expression of lncRNAs in the pathogenesis of aggressive cancers such as pancreatic ductal adenocarcinoma was particularly emphasized (Takahashi et al, 2021).…”

Research Progress of circRNAs in Glioblastoma

“…This structure may protect it from degradation by RNA exonuclease (RNAser) and thus has higher stability than linear RNA ( Suzuki and Tsukahara, 2014 ; Di Timoteo et al, 2020 ; Wang et al, 2021h ). Conservative, circRNAs is highly conserved across species ( AbouHaidar et al, 2014 ; Mao et al, 2021 ; Meyer et al, 2021 ). Specificity, mainly in terms of cell type specificity and tissue specificity ( Shang et al, 2019 ; Gokool et al, 2020 ; Huang and Zhu, 2021 ).…”