Identification of Circular RNAs Associated With Chemoresistance in Colorectal Cancer

Abstract

Chemoresistance is a major clinical obstacle for the treatment of colorectal cancer (CRC). Circular RNAs (circRNAs) are a new type of non-coding RNA that participated in the development of chemoresistance. However, the profiles and effects of circRNAs in 5-fluorouracil (5-Fu) and cisplatin resistance of CRC are still unclear and need to be elucidated. In the present study, the profiles of circRNAs in CRC chemoresistant (HCT8/5-Fu and HCT8/DDP) and chemosensitive (HCT8) cell lines were identified via RNA-sequencing. In total, 48 and 90 differentially expressed (DE)-circRNAs were detected in HCT8/5-Fu and HCT8/DDP cell lines, respectively. Gene Ontology enrichment and Kyoto Encyclopedia of Genes and Genomes pathway analysis were conducted on the host genes of DE-circRNAs; the results showed that the most significant enrichment pathways in HCT8/5-Fu and HCT8/DDP cell lines were base excision repair and Hippo signaling pathway, respectively. In addition, 11 common DE-circRNAs in the two drug-resistant cell lines (two are upregulated and nine are downregulated) were screened and verified by quantitative real-time PCR; hsacirc_023607 and hsacirc_007420 were found to be the circRNAs with the highest upregulation and downregulation fold changes. However, functional studies showed hsacirc_023607 has no effect on CRC chemoresistance. Therefore, the regulatory networks of targeted miRNAs related to 5-Fu or cisplatin resistance were predicted and constructed, in which hsacirc_002482 was identified as a hub gene, and its overexpression could suppress HCT8/5-Fu and HCT8/DDP cell proliferation and promote cell apoptosis, and enhance cell chemosensitivity. Taken together, these results of the study suggested that hsacirc_002482 may play important roles in chemoresistance of CRC.

LINC02418 upregulates EPHA2 by competitively sponging miR-372-3p to promote 5-Fu/DDP chemoresistance in colorectal cancer

“…In our previous study, we confirmed that CRC chemoresistant cell lines (HCT8/5-Fu, HCT8/DDP) were more resistant to drugs than parental cells HCT8 ( 25 ), which laid the foundation for whole-transcriptome sequencing to obtain the profiles of lncRNAs, miRNAs and mRNAs in the parental cell lines and two drug-resistant cell lines. Compared with parental cells, DE lncRNAs, miRNAs and mRNAs were screened out in drug-resistant cells with the criteria of |log2FoldChange| >1 and P < 0.05.…”

“…A normal colon epithelial cell line (CCD-18Co) was purchased from the American Type Culture Collection (Manassas, VA), HCT8, HCT116 and SW480 CRC cell lines and 293T cells were purchased from the China Center for Type Culture Collection (Wuhan, China) with short tandem repeat DNA profiling analysis, and cultured for fewer than 6 months after resuscitation. Chemoresistant CRC cell lines (HCT8/5-Fu and HCT8/DDP) were derived from the parental cell line HCT8 by continuous exposure to drugs ( 25 ). CCD-18Co and 293T cells were cultured in Dulbecco’s modified Eagle’s medium (Gibco, MD) containing 10% fetal bovine serum (Gibco, MD), HCT8, HCT116, SW480, HCT8/5-Fu and HCT8/DDP cells were maintained in RPMI-1640 (Gibco, MD) supplemented with 10% fetal bovine serum (Gibco, MD) and 1% penicillin/streptomycin (Gibco, MD).…”

“…Total RNAs were extracted using TRIzol reagent (Life Technologies, CA) according to the manufacturer’s protocol. The quantity of total RNA samples was assessed according to the description in our previous study ( 25 ).…”

Circ‐ERBB2 knockdown sensitized colorectal cancer cells to 5‐FU via miR‐181a‐5p/PTEN/Akt pathway

“…More and more articles suggest that circRNA dysregulation modulates tumor resistance to 5‐FU. [ 26,27 ] In addition, circRNA‐miRNA‐mRNA regulatory network also has a critical effect on 5‐FU resistance of tumor. [ 28 ]…”

“…More and more articles suggest that circRNA dysregulation modulates tumor resistance to 5-FU. [26,27] In addition, circRNA-miRNA-mRNA regulatory network also has a critical effect on 5-FU resistance of tumor. [28] In this study, we first explored the expression of circ-ERBB2 in colorectal cancer and determined its carcinogenic effect, and then analyzed the miRNA that could interact with circ-ERBB2 through bioinformatics.…”