Circular RNA ITCH attenuates the progression of nasopharyngeal carcinoma by inducing PTEN upregulation via miR‐214

• Published in: The journal of gene medicine Vol. 24; no. 1; pp. e3391 - n/a
• Main Authors: Wang, Liuzhong, Sang, Jianzhong, Zhang, Yamin, Gao, Ling, Zhao, Dongli, Cao, Hua
• Format: Journal Article
• Language: English
• Published: England Wiley Periodicals Inc 01.01.2022
• Subjects: Carcinogenesis; Cell Line, Tumor; Cell migration; Cell proliferation; Cell Proliferation - genetics; Circular RNA; circular RNA itchy E3 ubiquitin protein ligase; Gene expression; Gene therapy; Humans; Immunohistochemistry; Kinases; MicroRNAs - genetics; MicroRNAs - metabolism; microRNA‐214; miRNA; Nasopharyngeal carcinoma; Nasopharyngeal Carcinoma - genetics; Nasopharyngeal Carcinoma - pathology; Nasopharyngeal Neoplasms - genetics; Nasopharyngeal Neoplasms - pathology; Nasopharynx; phosphatase and tensin homolog; Polymerase chain reaction; PTEN Phosphohydrolase - genetics; PTEN Phosphohydrolase - metabolism; PTEN protein; RNA, Circular - genetics; Tensin; Throat cancer; Tumorigenesis; Ubiquitin; Ubiquitin-protein ligase; Ubiquitin-Protein Ligases - genetics; Up-Regulation; Western blotting; Xenografts; circular RNA itchy E3 ubiquitin protein ligase; nasopharyngeal carcinoma; phosphatase and tensin homolog; microRNA-214
• ISSN: 1099-498X; 1521-2254; 1521-2254
• DOI: 10.1002/jgm.3391

Background Circular RNA itchy E3 ubiquitin protein ligase (circ‐ITCH) has previously been reported to play a key role in carcinogenesis. Nevertheless, the role of circ‐ITCH in nasopharyngeal carcinoma (NPC) remains to be explored. Methods Gene expression analysis was performed using a quantitative real‐time polymerase chain reaction, western blotting and immunohistochemistry. The role of circ‐ITCH in NPC was explored using 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyl tetrazolium bromide, colony formation, transwell invasion, scratch healing and xenograft tumor assays. Furthermore, luciferase reporter assay was carried out to assess the interactions among circ‐ITCH, microRNA‐214 (miR‐214) and phosphatase and tensin homolog (PTEN). Results The levels of circ‐ITCH and PTEN were decreased, whereas the level of miR‐214 was increased in NPC tissues collected from 28 subjects compared to normal nasopharynx tissues collected from 15 subjects. Moreover, a negative correlation between circ‐ITCH and miR‐214 expression and a positive correlation between circ‐ITCH and PTEN expression were observed in NPC tissues. Downregulation of circ‐ITCH expression was also observed in NPC cell lines. In addition, upregulation of circ‐ITCH markedly inhibited NPC cell proliferation, migration and invasion. Furthermore, circ‐ITCH was confirmed to exert its function by sponging miR‐214. PTEN was found to be a direct target gene of miR‐214 and its expression was negatively correlated with miR‐214 expression in NPC tissues. Moreover, our results showed that the circ‐ITCH/miR‐214 axis regulated NPC proliferation, migration and invasion through regulating the expression of PTEN. Upregulation of circ‐ITCH or PTEN blocked miR‐214‐mediated promotion of NPC tumorigenesis in vitro. Additionally, upregulation of circ‐ITCH also suppressed NPC tumorigenesis in vivo. Conclusions The present study demonstrated that circ‐ITCH suppressed NPC tumorigenesis by upregulating PTEN expression through interacting with miR‐214, thus proposing a novel mechanism for NPC inhibition. circ‐ITCH inhibited the tumorigenesis of NPC in vivo. SUNE1 cells stably transfected with pcDNA‐circ‐ITCH or pcDNA were subcutaneously injected into BALB/c nude mice. Tumor size was monitored every 1 week, consecutively for 6 weeks. (A) The growth curve of xenograft tumors from circ‐ITCH‐overexpressing SUNE1 cells and control cells in nude mice. (B) At 42 days after injection, mice were killed and tumors were excised and weighed. (C) IHC (scale bar = 20 μm) and (D) western blot analysis of Bax expression in xenograft tumors. (E) qRT‐PCR analysis of miR‐214 expression showing reduced expression of miR‐214 in tumors from circ‐ITCH‐overexpressing SUNE1 cells. (F) Western blot analysis of PTEN expression in xenograft tumors. **p < 0.01 and ***p < 0.001.