Circ_0008039 supports breast cancer cell proliferation,migration, invasion,and glycolysis by regulating the miR‐140‐3p/SKA2 axis

Circular RNAs (circRNAs) have been shown to modulate gene expression and participate in the development of multiple malignancies. The purpose of this study was to investigate the role of circ_0008039 in breast cancer (BC). The expression of circ_0008039, miR‐140‐3p, and spindle and kinetochore‐associated protein 2 (SKA2) was detected by qRT‐PCR. Cell viability, colony formation, migration, and invasion were evaluated using methylthiazolyldiphenyl‐tetrazolium bromide (MTT) assay, colony formation assay, and transwell assay, respectively. Glucose consumption and lactate production were measured using commercial kits. Protein levels of hexokinase II (HK2) and SKA2 were determined by western blot. The interaction between miR‐140‐3p and circ_0008039 or SKA2 was verified by dual‐luciferase reporter assay. Finally, a mouse xenograft model was established to investigate the roles of circ_0008039 in BC in vivo. We found that circ_0008039 and SKA2 were upregulated in BC tissues and cells, while miR‐140‐3p was downregulated. Knockdown of circ_0008039 suppressed BC cell proliferation, migration, invasion, and glycolysis. Moreover, miR‐140‐3p could bind to circ_0008039 and its inhibition reversed the inhibitory effect of circ_0008039 interference on proliferation, migration, invasion, and glycolysis in BC cells. SKA2 was verified as a direct target of miR‐140‐3p and its overexpression partially inhibited the suppressive effect of miR‐140‐3p restoration in BC cells. Additionally, circ_0008039 positively regulated SKA2 expression by sponging miR‐140‐3p. Consistently, silencing circ_0008039 restrained tumor growth via increasing miR‐140‐3p and decreasing SKA2. In conclusion, circ_0008039 downregulation suppressed BC cell proliferation, migration, invasion, and glycolysis partially through regulating the miR‐140‐3p/SKA2 axis, providing an important theoretical basis for treatment of BC.

Abbreviations

ANOVA

analysis of variance

BC

breast cancer

circRNAs

circular RNAs

DMSO

dimethyl sulfoxide

ECAR

extracellular acidification rate

ECL

enhanced chemiluminescence

FBS

fetal bovine serum

HK2

hexokinase II

MEGM

mammary epithelial growth medium

miR‐140‐3p

microRNA‐140‐3p

MTT

methylthiazolyldiphenyl‐tetrazolium bromide

PBS

phosphate‐buffered saline

PRKAR1B

protein kinase A regulatory subunit R1‐beta

SD

standard ± deviation

SKA2

spindle and kinetochore‐associated protein 2

     

circ_0000619通过调控miR-595/GLS轴对食管鳞状细胞癌细胞增殖及谷氨酰胺代谢的影响

目的:探讨circ_0000619/miR-595/GLS轴对人食管鳞状细胞癌（esophageal squamous cell carcinoma,ESCC）KYSE150细胞增殖、迁移、侵袭和谷氨酰胺代谢的影响及其可能的机制。方法:采用qPCR法检测KYSE150细胞中circ_0000619、miR-595、谷氨酰胺酶（glutaminase,GLS）mRNA等表达水平,Western blot检测KYSE150细胞中GLS蛋白的表达情况,使用细胞计数试剂盒-8（cell counting kit-8,CCK-8）试剂盒、Transwell法分别检测KYSE150细胞增殖、迁移及侵袭能力,使用相应的检测试剂盒检测KYSE150细胞谷氨酰胺消耗、谷氨酸产生及ATP产生水平,利用生物信息学分析技术及双荧光素酶报告基因实验分析并检测circ_0000619、miR-595与GLS mRNA之间的相互作用关系。结果:circ_0000619在ESCC细胞系中呈现高表达,其亲本基因DENND4A mRNA在食管癌组织中呈高表达（P<0.01）;敲减circ_0000619显著抑制KYSE150细胞的增殖、侵袭和迁移能力（P<0.01）,并显著抑制KYSE150细胞的谷氨酰胺消耗、谷氨酸及ATP产生水平（P<0.01）;敲减circ_0000619显著上调miR-595表达（P<0.01）,抑制GLS mRNA（P<0.01）及蛋白的表达;双荧光素酶报告基因实验显示在KYSE150细胞中,circ_0000619与miR-595存在靶向结合、miR-595与GLS存在靶向结合（P<0.01）。circ_0000619敲低显著降低了KYSE150细胞谷氨酰胺代谢和细胞增殖,并且这些作用被miR-595抑制或GLS过表达部分逆转。结论:circ_0000619能通过靶向调控miR-595/GLS轴增强ESCC细胞谷氨酰胺代谢及细胞增殖,并可能成为潜在的ESCC治疗靶点。     

circ_0001721/miR-198对前列腺癌细胞生物学行为的影响

目的:探讨circ_0001721/miR-198分子轴对人前列腺癌细胞DU145生物学行为的影响及相关作用机制。方法:应用qRT-PCR法检测circ_0001721、miR-198的表达量;DU145细胞转染si-circ_0001721、miR-198 mimics、anti-miR-198以及相应的对照（si-NC、miR-NC、anti-miR-NC）;CCK-8法、平板克隆形成实验、流式细胞术、Transwell实验检测细胞增殖、克隆、凋亡、迁移及侵袭;双荧光素酶报告实验验证circ_0001721与miR-198的靶向关系;Western blot检测E-cadherin、N-cadherin蛋白表达量。结果:与癌旁组织比较,circ_0001721在前列腺癌组织中高表达（P＜0.05）,而miR-198在前列腺癌组织中低表达（P＜0.05）;与转染si-NC或转染miR-NC相比,si-circ_0001721或miR-198 mimics可以提高细胞增殖抑制率、凋亡率和E-cadherin蛋白水平（P＜0.05）,降低克隆形成数、迁移和侵袭数以及N-cadherin蛋白水平（P＜0.05）;circ_0001721可靶向结合miR-198;与共转染si-circ_0001721和anti-miR-NC相比,共转染si-circ_0001721和anti-miR-198降低了细胞增殖抑制率、凋亡率和E-cadherin蛋白水平（P＜0.05）,而增加了克隆形成数、迁移和侵袭数以及N-cadherin蛋白水平（P＜0.05）。结论:敲低circ_0001721可通过上调miR-198抑制前列腺癌细胞的生长和转移。     

Hsa_circ_0074491 regulates the malignance of cholesteatoma keratinocytes by modulating the PI3K/Akt pathway by binding to miR-22-3p and miR-125a-5p: An observational study

Cholesteatoma is a benign cystic lesion that can continue to grow like a tumor. Circular ribonucleic acid (RNA) hsa_circ_0074491 (circ_0074491) has been reported to be down-regulated in cholesteatoma tissues. However, the role and regulatory mechanism of circ_0074491 in the growth of cholesteatoma are unclear.The expression of circ_0074491, microRNA (miR)-22-3p, and miR-125a-5p in cholesteatoma tissues was detected by quantitative real-time polymerase chain reaction. The proliferation, cell cycle, apoptosis, migration, and invasion of cholesteatoma keratinocytes were evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, plate clone, flow cytometry, or transwell assays. Several protein levels were examined by western blotting. The targeting relationship between miR-22-3p or miR-125a-5p and circ_0074491 was verified via dual-luciferase reporter and RNA pull-down assays.We observed the downregulation of circ_0074491 in cholesteatoma tissues. Furthermore, circ_0074491 knockdown facilitated cell proliferation, migration, invasion, and repressed cell apoptosis in cholesteatoma keratinocytes. Circ_0074491 was verified as a decoy for miR-22-3p and miR-125a-5p in cholesteatoma keratinocytes. Both miR-22-3p and miR-125a-5p silencing reversed the impacts of circ_0074491 silencing on proliferation, apoptosis, migration, and invasion of cholesteatoma keratinocytes. Also, circ_0074491 knockdown activated the PI3K/Akt pathway in cholesteatoma keratinocytes via miR-22-3p and miR-125a-5p.Circ_0074491 played a suppressive role in cholesteatoma through inactivating the PI3K/Akt pathway via binding to miR-22-3p and miR-125a-5p, which provided a novel evidence for the involvement of circRNA in the development of cholesteatoma.     

circ_0006089 promotes gastric cancer growth,metastasis, glycolysis,and angiogenesis by regulating miR‐361‐3p/TGFB1

Circular RNA (circRNA) participates in a variety of pathophysiological processes, including the development of gastric cancer (GC). However, the role of circ_0006089 in GC progression and its underlying molecular mechanism need to be further revealed. Quantitative real‐time PCR was utilized for detecting circ_0006089, microRNA (miR)‐361‐3p and transforming growth factor‐β1 (TGFB1) expression. The interaction between miR‐361‐3p and circ_0006089 or TGFB1 was confirmed using a dual‐luciferase reporter assay and an RNA immunoprecipitation (RIP) assay. Cell proliferation, metastasis, apoptosis, and angiogenesis were determined using colony formation assay, EdU assay, transwell assay, flow cytometry, and tube formation assay. Cell glycolysis was evaluated by detecting glucose consumption, lactate production, and ATP levels. In addition, western blot (WB) analysis was used to measure protein expression. Xenograft tumor models were used to assess the effect of circ_0006089 knockdown on GC tumorigenesis. circ_0006089 had been found to be upregulated in GC tissues and cells, and it could act as an miR‐361‐3p sponge. circ_0006089 knockdown suppressed GC proliferation, metastasis, glycolysis, angiogenesis, and increased apoptosis, while this effect could be revoked by miR‐361‐3p inhibitor. TGFB1 was targeted by miR‐361‐3p, and its overexpression reversed the effects of miR‐361‐3p on GC cell function. Also, circ_0006089 promoted TGFB1 expression via sponging miR‐361‐3p. Animal experiments showed that silenced circ_0006089 inhibited GC tumorigenesis through the miR‐361‐3p/TGFB1 pathway. Our results revealed that the circ_0006089/miR‐361‐3p/TGFB1 axis contributed to GC progression, confirming that circ_0006089 might be a potential therapeutic target for GC.     

Hsa_circ_0007142 contributes to cisplatin resistance in esophageal squamous cell carcinoma via miR‐494‐3p/LASP1 axis

BackgroundChemoresistance is one of the major obstacles for tumor treatment. Circular RNAs (circRNAs) have been confirmed to play vital roles in chemoresistance of cancer, including esophageal squamous cell carcinoma (ESCC). We investigated the roles and mechanisms of circ_0007142 in cisplatin (DDP) resistance of ESCC.MethodsQuantitative real‐time polymerase chain reaction (qRT‐PCR) was conducted to determine the levels of circ_0007142, DOCK1 mRNA, microRNA‐494‐3p (miR‐494‐3p) and LIM And SH3 Protein 1 (LASP1) mRNA. RNase R assay was conducted to analyze the characteristic of circ_0007142. Cell Counting Kit‐8 (CCK‐8) assay was performed to evaluate IC50 of DDP. Flow cytometry analysis, 5‐ethynyl‐2’‐deoxyuridine (EdU) assay and transwell assay were carried out to examine cell apoptosis, proliferation and invasion, respectively. Dual‐luciferase reporter assay was employed to verify the association between miR‐494‐3p and circ_0007142 or LASP1. Murine xenograft assay was conducted to investigate the role of circ_0007142 in DDP resistant in vivo. The protein level of LASP1 in tumors was measured by Immunohistochemistry (IHC) analysis.ResultsCirc_0007142 was upregulated in DDP‐resistant ESCC tissues and cells. Circ_0007142 knockdown improved DDP sensitivity, induced cell apoptosis and hampered cell proliferation and invasion in DDP‐resistant ESCC cells. Circ_0007142 functioned as the sponge for miR‐494‐3p and miR‐494‐3p inhibition reversed the impacts of circ_0007142 knockdown on DDP resistance, cell apoptosis, proliferation, and invasion. LASP1 was a target of miR‐494‐3p, and the effects on DDP resistance, cell apoptosis, growth, and invasion mediated by LASP1 downregulation were rescued by miR‐494‐3p inhibition. Moreover, circ_0007142 knockdown enhanced DDP sensitivity in vivo.ConclusionCirc_0007142 improved DDP resistance of ESCC by upregulating LASP1 via sponging miR‐494‐3p.     

信号转导及转录激活因子4（STAT4）介导的circ_0001879表达对高糖条件下人视网膜微血管内皮细胞增殖和凋亡的影响

目的　探讨信号转导及转录激活因子4（STAT4）介导的circ_0001879表达对高糖处理的人视网膜微血管内皮细胞(HREC)增殖和凋亡的影响。方法　将HREC分为正常组（5.5 mmol·L^-1葡萄糖）、高糖组（25.0 mmol·L^-1葡萄糖）和甘露醇对照组（5.5 mmol·L^-1葡萄糖+19.5 mmol·L^-1甘露醇）,继续培养。将高糖组细胞进一步分组,进行相应转染处理。采用实时荧光定量PCR检测各组细胞circ_0001879、miR-338和多效生长因子（PTN）的表达。通过MTT、流式细胞术分析circ_0001879调控miR-338/PTN对HREC增殖和凋亡的影响。采用双荧光素酶报告实验确定miR-338和circ_0001879、miR-338和PTN之间的相互作用;ChIP实验验证STAT4与circ_0001879的结合。结果　与甘露醇对照组HREC中 circ_0001879（1.21±0.13）、miR-338（0.99±0.08）和PTN（1.12±0.11）的表达相比,高糖组HREC中circ_0001879（2.93±0.21）和PTN（3.62±0.33）的表达显著升高,而miR-338（0.44±0.05）的表达降低,差异均有统计学意义（均为P<0.05）。通过MTT和流式细胞术检测各组细胞增殖活力和凋亡率,结果显示,过表达miR-338能够抑制高糖处理的HREC的增殖活力,促进HREC凋亡,而敲减miR-338的表达则作用相反;miR-inhibitor对高糖处理的HREC的作用能够被si-circ部分抑制。双荧光素酶报告实验结果显示,PTN是miR-338的一个靶基因,且其表达受miR-338和circ_0001879的影响。ChIP实验结果显示,STAT4与circ_0001879启动子区域的B1、B3结合,STAT4能够与circ_0001879的启动子结合并且促进circ_0001879的转录。结论　STAT4能够激活circ_0001879的转录,circ_0001879进一步通过调节miR-338/PTN轴促进高糖条件下HREC增殖,抑制细胞凋亡。     

松果菊苷通过circ_0046264/miR-510/OPCML对皮肤鳞状细胞癌A431细胞增殖、凋亡的影响

目的 探讨松果菊苷对皮肤鳞状细胞癌A431细胞增殖及凋亡的影响及其作用机制.方法 体外培养人皮肤鳞状细胞癌A431细胞,采用不同质量浓度(12.5、25.0、50.0μg/L)的松果菊苷处理A431细胞.将circ_0046264对照空载体(pcDNA)、circ_0046264过表达载体(pcDNA-circ_004...     

Circ_0080425通过miR-1182/FGF9轴影响高糖环境下血管内皮细胞功能

目的 探讨circ_0080425调控高糖环境下内皮功能的作用及分子机制。方法 采用qRT-PCR检测在高糖环境下培养的人血管内皮细胞(human vascular endothelial cells，HUVECs)中circ_0080425的表达变化，通过小干扰RNA（siRNA）对circ_0080425进行敲低，并利用CCK-8、平板克隆、Transwell和流式细胞术，观察circ_0080425对高糖培养下的HUVECs增殖、迁移以及凋亡等生物学特性的影响。利用生物信息学网站预测circ_0080425的下游miRNA以及靶基因，并通过双荧光素酶报告实验验证分子间的相互结合。此外，通过sponge慢病毒以及质粒转染对目标分子的表达水平进行调控，并采用CCK-8、平板克隆、Transwell和流式细胞术等进行功能学验证。结果 Circ_0080425在高糖培养条件下HUVECs中表达上调，且circ_0080425可通过miR-1182/FGF9轴调控高糖条件下HUVECs的增殖、迁移和凋亡（P＜0.05）。结论 Circ_0080425可通过miR-1182/FGF9轴影响高糖环境下的血管内皮功能。