RETRACTED: circIFT80 Functions as a ceRNA of miR-1236-3p to Promote Colorectal Cancer Progression

Abstract

Circular RNAs (circRNAs), a recently identified new member of non-coding RNAs, are demonstrated to participate in diverse biological processes; however, the molecular mechanisms that link circRNAs with colorectal cancer (CRC) are not well understood. In the present study, we attempted to explore the roles of the exosomal circRNAs on CRC progression. We first compared the expression patterns of exosomal circRNAs between the plasma of CRC patients and healthy controls. We identified 448 significantly dysregulated exosomal circRNAs in CRC plasma. We focused on hsa_circ_0067835, which is located on chromosome 3 and derived from IFT80; thus, we named it circIFT80. Then, the expression of circIFT80 was detected in 58 CRC tissues and cell lines by qRT-PCR. Functional assays were performed to evaluate the effects of circIFT80 on tumor growth in vitro and in vivo. The relationship between circIFT80 and miR-1236-3p was confirmed by luciferase reporter assay. We found that circIFT80 was significantly upregulated in CRC serum exosomes, CRC tissues, and CRC cell lines compared with normal control. Silencing circIFT80 suppressed CRC cell growth both in vitro and in vivo. We further demonstrated that circIFT80/miR-1236-3p/HOXB7 axis plays an important role in regulating CRC progression. Dual-luciferase reporter system validated the direct interaction of circIFT80, miR-1236-3p, and HOXB7. Western blot verified that inhibition of circIFT80 decreased HOXB7 expression, while a miR-1236-3p inhibitor attenuated the effect of inhibition of circIFT80. In conclusion, these data suggest that circIFT80 is a central component linking circRNAs to the progression of CRC via a miR-1236-3p/HOXB7 axis.

Exosomal Non Coding RNA in LIQUID Biopsies as a Promising Biomarker for Colorectal Cancer

“…In addition, there was an inverse correlation between the expression levels of the circRNAs and their respective miR targets in cell lines and serum exosomes from CRC patients. Furthermore, circFMN2 and circIFT80 knockdown decreased the expressions of hTERT and HOXB7, respectively, which was counteracted via introducing an inhibitor of their miR targets [131,132]. These results demonstrate that exosomal circRNAs circFMN2 and circIFT80 are potential prognostic markers.…”

“…Moreover, circFMN2 and circIFT80 knockdown in vitro and in vivo significantly inhibited cell proliferation. There was an increase in G0/G1 phase cells and a decrease in the G2/M phase cells [131,132]. However, circFMN2 knockdown did not have that effect on the human colonic epithelial cell line.…”

“…This makes circFMN2 a promising therapeutic target, since normal cells were not affected. In addition, circIFT80 knockdown increased CRC cell apoptosis, while circFMN2 knockdown showed no change in CRC cell apoptosis [131,132]. Furthermore, it has been shown that circIFT80 promotes EMT.…”

“…Furthermore, it has been shown that circIFT80 promotes EMT. The invasion and migration of CRC cells significantly increased in the case of circIFT80 overexpression, which was associated with a decrease in E-cadherin expression and an increase in the expression of vimentin and N-cadherin [132] (Table 3). Experiments have shown that the mechanism of action of circFMN2 and circIFT80 is through the circFMN2/miR-1182/hTERT axis and circIFT80/miR-1236-3p/HOXB7 axis, respectively.…”

CircSEC24A promotes colorectal cancer progression by regulating miR-488-3p/TMEM106B axis

“…For example, circ_0001178 played a promotional role in CRC metastasis [6]. CircIFT80 level was notably raised in CRC and contributed to CRC cell growth in vitro and tumorigenesis in vivo [7]. On the contrary, circ_0026344 overexpression hampered CRC cell metastasis and epithelial-mesenchymal transition (EMT) process [8].…”