Exosomal Circular RNA RNA-seq Profiling and the Carcinogenic Role of Exosomal circ-CYP24A1 in Cutaneous Squamous Cell Carcinoma

Abstract

Objective: Aberrantly expressed exosomal circular RNAs (circRNAs) have been reported in various human cancers. Nevertheless, it remains elusive in cutaneous squamous cell carcinoma (cSCC). Herein, based on RNA-seq, we systematically uncovered the expression and implication of exosomal circRNAs in cSCC.Methods: Plasma exosomes derived from cSCC and healthy subjects were characterized by nanoparticle tracking analysis (NTA), transmission electron microscopy (TEM), and western blot. Differentially expressed exosomal circular RNAs (circRNAs) were screened by RNA-seq analysis, which were validated by RT-qPCR. Among them, the biological structure of circ-CYP24A1 was validated by Sanger sequencing and RNase R digestion. Si-circ-CYP24A1 was transfected into exosomes, followed by incubation with A431 and SCL-1 cells. Then, viability, apoptosis, migration, and invasion were evaluated by CCK-8, TUNEL staining and migration assays.Results: This study identified 25 up- and 76 down-regulated exosomal circRNAs in cSCC than healthy subjects. Among them, circulating circ-CYP24A1 was confirmed to be up-regulated in cSCC. Circ-CYP24A1 had a covalently closed circular structure and was not sensitive to RNase R digestion. After incubation with si-circ-CYP24A1-transfected exosomes, proliferation, migration, and invasion were lowered while apoptosis was enhanced in A431 and SCL-1 cells. Meanwhile, si-circ-CYP24A1-transfected exosomes significantly decreased the expression of downstream targets CDS2, MAVS, and SOGA in cSCC cells.Conclusion: Collectively, our study identified that targeting exosomal circ-CYP24A1 could suppress cSCC progression by weakening tumor malignant behaviors, which might provide a promising therapeutic target and non-invasive diagnostic biomarker for cSCC.

Cancer-Derived Extracellular Vesicles as Biomarkers for Cutaneous Squamous Cell Carcinoma: A Systematic Review

“…One study used recessive dystrophic epidermolysis bullosa (RDEB)-associated SCC cells (RDEB-SCC cells) for disease-specific profiling. There were three studies that investigated EV-associated RNA [ 17 , 42 , 43 ], three studies on surface-associated proteins [ 17 , 38 , 40 ], and one study on EV-associated DNA [ 41 ].…”

Microarray Identifies a Key Carcinogenic Circular RNA 0008594 That Is Related to Non-Small-Cell Lung Cancer Development and Lymph Node Metastasis and Promotes NSCLC Progression by Regulating the miR-760-Mediated PI3K/AKT and MEK/ERK Pathways

“…Since the introduction of circRNA in cancer research and the progress of genetic detection technology (such as microarray and RNA sequencing), an increasing number of studies have been conducted to investigate the underlying role of the circRNA profile in cancers, including lung cancer (20,(33)(34)(35)(36). A previous study identified five upregulated circRNAs and 30 downregulated circRNAs in small-cell-lung cancer (SCLC) tissues compared to adjacent non-cancerous tissues using nextgeneration sequencing (37).…”

Roles and clinical application of exosomal circRNAs in the diagnosis and treatment of malignant tumors

“…Circ-0001068 is introduced into T cells and induces PD1 expression via exosomes as a ceRNA for miR-28-5p; it represents a novel ovarian cancer biomarker and inducer of PD1 expression in T cells [ 81 ]. Targeting exosomal circ-CYP24A1 was found to inhibit the progression of cutaneous squamous cell carcinoma by attenuating the malignant behavior of the tumor [ 82 ]. It is thus a promising therapeutic target and non-invasive diagnostic biomarker for cutaneous squamous cell carcinoma.…”