Colorectal cancer (CRC) is a prevalent malignant tumor with a poor prognosis. Circular RNA (circRNA) circ_0007334 is related to cell proliferation in CRC. This study is designed to explore the role and mechanism of circ_0007334 in CRC progression. Circ_0007334, microRNA-577 (miR-577) and kruppel-like factor 12 (KLF12) levels were measured by real-time quantitative PCR (RT-qPCR). Exosomes were detected by a transmission electron microscope and nanoparticle tracking analysis (NTA). CD63, TSG101, matrix metallopeptidase-2 (MMP-2), MMP-9, VEGFA and KLF12 protein levels were examined by western blot assay. The binding relationship between miR-577 and circ_0007334 or KLF12 was predicted by circRNA interactome or Starbase and verified by a dual-luciferase reporter and RNA immunoprecipitation (RIP) assays. Cell viability, colony number, migration, invasion and angiogenesis were detected by cell counting kit-8 (CCK-8), colony formation, wound healing, transwell and tube formation assays. The biological role of circ_0007334 was examined by the xenograft tumor model in vivo. Circ_0007334 and KLF12 were increased, and miR-577 was decreased in CRC tissues and cells. Also, circ_0007334 expression was upregulated in CRC cell-derived exosomes. Circ_0007334 deficiency repressed cell viability, colony formation, migration, invasion, and angiogenesis in CRC cells. Mechanically, circ_0007334 could regulate KLF12 expression by sponging miR-577. Circ_0007334 downregulation or exosomal circ_0007334 silencing blocked CRC tumor growth in vivo. These results presented that circ_0007334 deficiency exerts a tumor-suppressor by the miR-577/KLF12 axis in CRC, and indicated that exosomal circ_0007334 could hinder CRC tumor growth and angiogenesis in vivo. Our findings provided a novel therapeutic strategy for CRC. Anti-Cancer Drugs 33: e409-e422
Background:
Increasing evidence revealed that circular RNAs (circRNAs) are involved in colorectal cancer progression. However, the potential function of circ_0001535 in colorectal cancer remains unclear.
Aims:
To investigate the mechanism of circ_0001535 by silencing circ_0001535 in colorectal cancer cells and nude mice.
Study Design:
A cell study.
Methods:
Expressions of circ_0001535, LIM and SH3 protein 1 (LASP1) mRNA, and miR-485-5p were detected by real-time quantitative polymerase chain reaction (RT-qPCR). Western blot analyses of LASP1, PCNA, cleaved caspase 3, snail 1, and OCT4 protein expression were performed. CCK-8, EdU, flow cytometry, transwell assays, and sphere formation were conducted to evaluate colorectal cancer cell proliferation, apoptosis, invasion, and stemness. Luciferase reporter assays, RNA pull-down, and RIP validated binding. A nude mice xenograft model was constructed.
Results:
Circ_0001535 was significantly upregulated in colorectal tissues and cells. Circ_0001535 knockdown suppressed the malignant behavior of colorectal cells such as proliferation, invasion, stemness, and tumor growth in vivo. This knockdown also induced apoptosis by sponging miR-485-5p and upregulating LASP1 expression.
Conclusion:
Circ_0001535 promotes colorectal cancer cell development by absorbing miR-485-5p and upregulating LASP1.
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