Zhao Yong, Cui Qichen, Shen Jian, Shen Weihong, Weng Yuan
Department of Thoracic and Cardiac Surgery, Affiliated Hospital of Jiangnan University, Wuxi, Jiangsu, China.
Department of Clinical Laboratory, Affiliated Hospital of Jiangnan University, Wuxi, Jiangsu, China.
Histol Histopathol. 2023 Dec;38(12):1429-1441. doi: 10.14670/HH-18-597. Epub 2023 Feb 22.
Circular RNA (circRNA) has recently emerged as having a key role in cancer initiation and progression. A prior study exhibited that hsa_circ_0070440 (circ_0070440) was significantly up-regulated in lung cancer cells, but the role and molecular mechanism of circ_0070440 during lung adenocarcinoma (LUAD) development remain unclear.
Quantitative real-time polymerase chain reaction (qRT-PCR), Reverse transcription-PCR (RT-PCR), RNase R digestion, and Nuclear/cytoplasmic fractionation assay were employed to validate circ_0070440. Proliferation, apoptosis, viability, and ferrous iron level were measured by colony formation, 5-Ethynyl-2'-deoxyuridine (EdU), Annexin V-FITC/PI double staining, Cell Counting Kit-8 (CCK-8), and iron assay in LUAD cells. A xenograft mouse model was used for tumor growth in vivo. Western blot (WB) and immunohistochemistry (IHC) assays were utilized to determine the expression of solute carrier family 7 member 11 (SLC7A11), c-myc, and bcl-xL. The interactions between the circ_0070440/SLC7A11 axis and miR-485-5p were verified by RNA pull-down assay and dual-luciferase reporter assay.
Circ_0070440 was significantly up-regulated in LUAD cells. Knockdown of circ_0070440 inhibited growth and promoted both apoptosis and ferroptosis of LUAD cells. Moreover, our results showed that circ_0070440 contributed to malignant progression and suppressed ferroptosis of LUAD by sponging miR-485-5p and upregulating SLC7A11 expression. Furthermore, circ_0070440 and SLC7A11 levels were up-regulated, and the miR-485-5p level was more down-regulated in the tumor tissues than in normal tissues of LUAD patients.
Circ_0070440 modulated LUAD malignant progression and ferroptosis via targeting SLC7A11, implying a significant role of the circ_0070440/miR-485-5p/SLC7A11 axis in the diagnosis and treatment of LUAD.
环状RNA（circRNA）最近被发现在癌症的发生和发展中起关键作用。先前的一项研究表明，hsa_circ_0070440（circ_0070440）在肺癌细胞中显著上调，但circ_0070440在肺腺癌（LUAD）发展过程中的作用和分子机制仍不清楚。
采用定量实时聚合酶链反应（qRT-PCR）、逆转录-PCR（RT-PCR）、核糖核酸酶R消化和核/质分离分析来验证circ_0070440。通过集落形成、5-乙炔基-2'-脱氧尿苷（EdU）、膜联蛋白V-异硫氰酸荧光素/碘化丙啶双染、细胞计数试剂盒-8（CCK-8）和铁分析来检测LUAD细胞的增殖、凋亡、活力和亚铁离子水平。使用异种移植小鼠模型在体内研究肿瘤生长。采用蛋白质免疫印迹（WB）和免疫组织化学（IHC）分析来确定溶质载体家族7成员11（SLC7A11）、c-myc和bcl-xL的表达。通过RNA下拉分析和双荧光素酶报告基因分析验证circ_0070440/SLC7A11轴与miR-485-5p之间的相互作用。
circ_0070440在LUAD细胞中显著上调。敲低circ_0070440可抑制LUAD细胞的生长并促进其凋亡和铁死亡。此外，我们的结果表明，circ_0070440通过海绵化miR-485-5p并上调SLC7A11表达促进LUAD的恶性进展并抑制铁死亡。此外，与LUAD患者的正常组织相比，肿瘤组织中circ_0070440和SLC7A11水平上调，而miR-485-5p水平下调更明显。
Circ_0070440通过靶向SLC7A11调节LUAD的恶性进展和铁死亡，这意味着circ_0070440/miR-485-5p/SLC7A11轴在LUAD的诊断和治疗中具有重要作用。
