Circ-SKA3 Enhances Doxorubicin Toxicity in AC16 Cells Through miR-1303/TLR4 Axis.

Abstract

Doxorubicin (DOX) is a widely used anticancer drug, but its cardiotoxicity largely limits its clinical utilization. Circular RNA spindle and kinetochore-associated protein 3 (circ-SKA3) were found to be differentially expressed in heart failure patients. In this study, we investigated the role and mechanism of circ-SKA3 in DOX-induced cardiotoxicity.The quantitative real-time polymerase chain reaction and western blot assays were applied to measure the expression of circ-SKA3, microRNA (miR) -1303, and toll-like receptor 4 (TLR4). The viability and apoptosis of AC16 cells were analyzed using cell counting kit-8, flow cytometry, and western blot assays. The interaction between miR-1303 and circ-SKA3 or TLR4 was verified using dual-luciferase reporter and RNA immunoprecipitation assays. Exosomes were collected from culture media by the use of commercial kits and then qualified by transmission electron microscopy.The expression of circ-SKA3 and TLR4 was increased, whereas miR-1303 expression was decreased in DOX-treated AC16 cells. DOX treatment promoted cell apoptosis and inhibited cell viability in AC16 cells in vitro, which was partially reversed by circ-SKA3 knockdown, TLR4 silencing, or miR-1303 overexpression. Mechanistically, circ-SKA3 served as a sponge for miR-1303 to upregulate TLR4, which was confirmed to be a target of miR-1303. Additionally, circ-SKA3 contributed to DOX-induced cardiotoxicity through the miR-1303/TLR4 axis. Further studies suggested that circ-SKA3 was overexpressed in exosomes extracted from DOX-mediated AC16 cells, which could be internalized by surrounding untreated AC16 cells.Circ-SKA3 enhanced DOX-induced toxicity in AC16 cells through the miR-1303/TLR4 axis. Extracellular circ-SKA3 was packaged into exosomes, and exosomal circ-SKA3 could function as a mediator in intercellular communication between AC16 cells.

• Authors: Bin Li, Xinyong Cai, Yunxia Wang, Hongmin Zhu, Ping Zhang, Panpan Jiang, Xu Yang, Jianhua Sun, Lang Hong, Liang Shao
• Journal: International heart journal (Int Heart J) Vol. 62 Issue 5 Pg. 1112-1123 (Sep 30 2021) ISSN: 1349-3299 [Electronic] Japan
• PMID: 34544967 (Publication Type: Journal Article)

Chemical References

• Cell Cycle Proteins
• MIRN1303 microRNA, human
• MicroRNAs
• Microtubule-Associated Proteins
• RNA, Circular
• Ska3 protein, human
• TLR4 protein, human
• Toll-Like Receptor 4
• Topoisomerase II Inhibitors
• Doxorubicin

Topics

• Apoptosis (drug effects)
• Cardiotoxicity (genetics)
• Cell Cycle Proteins (drug effects, genetics)
• Cell Survival (drug effects)
• Doxorubicin (toxicity)
• Exosomes (genetics)
• Heart Failure (genetics)
• Humans
• MicroRNAs (genetics)
• Microscopy, Electron, Transmission (methods)
• Microtubule-Associated Proteins (drug effects, genetics)
• Myocytes, Cardiac (drug effects, pathology)
• RNA, Circular (genetics)
• Toll-Like Receptor 4 (drug effects, genetics)
• Topoisomerase II Inhibitors (toxicity)
• Transfection (methods)
• Up-Regulation