CircRNA_100565 contributes to cisplatin resistance of NSCLC cells by regulating proliferation, apoptosis and autophagy via miR-337-3p/ADAM28 axis

2021 ◽  
Vol 30 (2) ◽  
pp. 261-273
Author(s):  
Youqing Zhong ◽  
Hui Lin ◽  
Qi Li ◽  
Chang Liu ◽  
Jinmei Shen
Keyword(s):  
Nsclc Patient ◽  
Xenograft Model ◽  
Cell Counting ◽  
Luciferase Reporter ◽  
Circular Rnas ◽  
Reaction Cell ◽  
In Vivo Experiments ◽  
Murine Xenograft Model ◽  
Nsclc Patients

Circular RNAs (circRNAs) have been revealed to involve in the chemoresistance of various cancers, including non-small cell lung cancer (NSCLC). Here, we further investigate the role of circRNA_100565 in NSCLC cisplatin (DDP) resistance. The expression of circRNA_100565 and microRNA (miR)-337-3p, and ADAM metallopeptidase domain 28 (ADAM28) mRNA was detected using quantitative real-time polymerase chain reaction. Cell viability and apoptosis were measured by cell counting kit-8 assay and flow cytometry, respectively. Western blot was used to detect the level of ADAM28 and autophagy-related protein. The interaction between miR-337-3p and circRNA_100565 or ADAM28 was confirmed by dual-luciferase reporter assay or pull-down assay. In vivo experiments were conducted via the murine xenograft model. We found CircRNA_100565 was up-regulated in NSCLC DDP-resistant tissues and cell lines, and its high expression was associated with shorter overall survival of NSCLC patients. CircRNA_100565 deletion mitigated DDP resistance, reflected by the suppression of proliferation and autophagy, the reduction of IC50 value, as well as enhancement of apoptosis in DDP-resistant NSCLC cells. MiR-377-3p was confirmed to directly bind to circRNA_100565 or ADAM28 3’-UTR. Moreover, circRNA_100565 indirectly regulated ADAM28 expression by sponging miR-377-3p in NSCLC cells. Additionally, circRNA_100565 deletion-induced sensitivity of NSCLC resistant cells to DDP could be remarkably attenuated by miR-377-3p inhibition or ADAM28 re-expression. Meanwhile, circRNA_100565 knockdown contributed to the anti-tumor effects of DDP on NSCLC in vivo. CONCLUSION: CircRNA_100565 was an independent prognostic factor for NSCLC patient survival, and enhanced the resistance of NSCLC cells to cisplatin by regulating cell proliferation, apoptosis and autophagy via miR-337-3p/ADAM28 axis, shedding light on the development of a novel therapeutic strategy to boost the effectiveness of NSCLC chemotherapy.

scholarly journals CircARVCF Contributes to Cisplatin Resistance in Gastric Cancer by Altering miR-1205 and FGFR1

2021 ◽  
Vol 12 ◽  
Author(s):  
Ruirui Zhang ◽  
Huanyu Zhao ◽  
Hongmei Yuan ◽  
Jian Wu ◽  
Haiyan Liu ◽  
...  
Keyword(s):  
Gastric Cancer ◽  
Colony Formation ◽  
Xenograft Model ◽  
Cell Counting ◽  
Luciferase Reporter ◽  
Migration And Invasion ◽  
Circular Rnas ◽  
Western Blot Assay ◽  
Major Barrier

Background: Chemoresistance is a major barrier to the treatment of human cancers. Circular RNAs (circRNAs) are implicated in drug resistance in cancers, including gastric cancer (GC). In this study, we aimed to explore the functions of circRNA Armadillo Repeat gene deleted in Velo-Cardio-Facial syndrome (circARVCF) in cisplatin (DDP) resistance in GC.Methods: The expression of circARVCF, microRNA-1205 (miR-1205) and fibroblast growth factor receptor 1 (FGFR1) was detected by quantitative real-time polymerase chain reaction (qRT-PCR), western blot assay or immunohistochemistry (IHC) assay. Cell Counting Kit-8 (CCK-8) assay and colony formation assay were performed to evaluate DDP resistance and cell colony formation ability. Transwell assay was conducted to assess cell migration and invasion. Flow cytometry analysis was done to analyze cell apoptosis. Dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay were manipulated to analyze the relationships of circARVCF, miR-1205 and FGFR1. Murine xenograft model was constructed to explore DDP resistance in vivo.Results: CircARVCF level was increased in DDP-resistant GC tissues and cells. CircARVCF silencing inhibited DDP resistance, colony formation and metastasis and induced apoptosis in DDP-resistant GC cells. CircARVCF directly interacted with miR-1205 and miR-1205 inhibition reversed circARVCF silencing-mediated effect on DDP resistance in DDP-resistant GC cells. FGFR1 served as the target gene of miR-1205. MiR-1205 overexpression restrained the resistance of DDP-resistant GC cells to DDP, but FGFR1 elevation abated the effect. In addition, circARVCF knockdown repressed DDP resistance in vivo.Conclusion: CircARVCF enhanced DDP resistance in GC by elevating FGFR1 through sponging miR-1205.

scholarly journals CircFOXM1 promotes the proliferation, migration, invasion, and glutaminolysis of glioblastoma by regulating the miR-577/E2F5 axis

2021 ◽  
Author(s):  
Xuhui Fan ◽  
Meng Liu ◽  
Li Fei ◽  
Zhihui Huang ◽  
Yufeng Yan
Keyword(s):  
Cell Proliferation ◽  
Xenograft Model ◽  
Circular Rna ◽  
Suppressive Effect ◽  
Cell Counting ◽  
Luciferase Reporter ◽  
Migration And Invasion ◽  
In Vivo Experiments

Circular RNA (circRNA) is a key regulator of tumor progression. However, the role of circFOXM1 in glioblastoma (GBM) progression is unclear. The aim of this study was to investigate the role of circFOXM1 in GBM progression. The expression levels of circFOXM1, miR-577 and E2F transcription factor 5 (E2F5) were examined by real-time quantitative PCR. Cell counting kit 8 assay, EdU staining and transwell assay were used to detect cell proliferation, migration, and invasion. The levels of glutamine, glutamate and α-ketoglutarate were determined to evaluate the glutaminolysis ability of cells. Protein expression was tested by western blot analysis. Dual-luciferase reporter assay, RNA pull-down assay and RNA immunoprecipitation assay were employed to verify the interaction between miR-577 and circFOXM1 or E2F5. Mice xenograft model for GBM was constructed to perform in vivo experiments. Our results showed that circFOXM1 was highly expressed in GBM tumor tissues and cells. Silencing of circFOXM1 inhibited GBM cell proliferation, migration, invasion, glutaminolysis, as well as tumor growth. MiR-577 could be sponged by circFOXM1, and its inhibitor could reverse the suppressive effect of circFOXM1 downregulation on GBM progression. E2F5 was a target of miR-577, and the effect of its knockdown on GBM progression was consistent with that of circFOXM1 silencing. CircFOXM1 positively regulated E2F5 expression, while miR-577 negatively regulated E2F5 expression. In conclusion, our data confirmed that circFOXM1 could serve as a sponge of miR-577 to enhance the progression of GBM by targeting E2F5, which revealed that circFOXM1 might be a biomarker for GBM treatment.

scholarly journals Circular RNA circ-PAN3 (hsa_circ_0100181) Promotes Hepatocellular Carcinoma Growth Through Sponging miR-153 to Elevate Cyclin D1 Expression

2020 ◽  
Author(s):  
Shuo Yu ◽  
Min Wang ◽  
Xu Li ◽  
Xingjun Guo ◽  
Renyi Qin
Keyword(s):  
Hepatocellular Carcinoma ◽  
Cell Proliferation ◽  
Cell Viability ◽  
Cyclin D1 ◽  
Colony Formation ◽  
Xenograft Model ◽  
Cell Counting ◽  
Luciferase Reporter ◽  
Circular Rnas

Abstract Background: Circular RNAs (circRNAs) are engaged in hepatocellular carcinoma (HCC) progression, but the mechanisms remain to be elucidated. This study aimed to unveil the expression pattern and potential biological mechanisms of a newly indentified circRNA, circ-PAN3, in HCC. Methods: Cell Counting Kit-8 (CCK‐8) assay and colony formation assay were used to assess cell proliferation. Transcription-quantitative PCR (RT-qPCR) analysis and western blot analysis were used to determine the relative expression level of mRNA and protein, respectively. Cell apoptosis assay was used to evaluate the apoptosis rate of transfected cells. CircInteractome and Targetscan were utilized to predict the possible targets of circRNAs and miRNAs, respectively. Luciferase reporter assay and RNA pull-down assay were used to assess the direct interaction of RNAs. HCC cancer xenograft model was used to evaluate the biological process of circ-PAN3 in vivo. Student’s t test, χ2 test or one-way ANOVA was adopted appropriately.Results: Circ-PAN3 was elevated in HCC tissues, and patients with high Circ-PAN3 expression had a poor survival outcome. Knockdown of circ-PAN3 expression suppressed cell viability, colony formation and cell proliferation in vitro and in vivo. Circ-PAN3 elevates cyclin D1 expression to promote HCC progression. Subsequently, using CircInteractome, miR-153 were confirmed to interact with circ-PAN3 and was downregulated by circ-PAN3. Further, using Targetscan, cyclin D1 was validated to interact with miR-153 and was downregulated by miR-153. Addition of miR-153 expression with corresponsive mimics significantly reduced the expression of cyclin D1. Notably, the inhibition of cell viability, colony formation and proliferation induced by knockdown of circ-PAN3 were recovered following the combination with miR-153 inhibitor, cyclin D1, respectively. Conclusion: Together, this study demonstrated that a novel circ-PAN3/miR-153/cyclin D1 axis regulatory axis that promoted HCC progression.

scholarly journals Circ_0082182 promotes oncogenesis and metastasis of colorectal cancer in vitro and in vivo by sponging miR-411 and miR-1205 to activate the Wnt/β-catenin pathway

2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Ruijie Liu ◽  
Ping Deng ◽  
Yonglian Zhang ◽  
Yonglan Wang ◽  
Cuiping Peng
Keyword(s):  
Cell Cycle ◽  
Cell Proliferation ◽  
Cell Apoptosis ◽  
Xenograft Model ◽  
Cell Counting ◽  
Luciferase Reporter ◽  
Migration And Invasion ◽  
Circular Rnas ◽  
Mesenchymal Transition

Abstract Background Circular RNAs (circRNAs) are a class of endogenous single-strand RNA transcripts with crucial regulation in human cancers. The objective of this study is to investigate the role of circ_0082182 in CRC and its specific functional mechanism. Methods The quantitative real-time polymerase chain reaction (qRT-PCR) was performed to measure the levels of circ_0082182, microRNA-411 (miR-411) and microRNA-1205 (miR-1205). Cell proliferation was detected by Cell counting Kit-8 (CCK-8) and colony formation assays. Flow cytometry was used for determining cell cycle and cell apoptosis. Cell apoptosis was also assessed by caspase3 and caspase9 activities. Cell migration and invasion were examined using scratch assay and transwell assay. The interaction between circ_0082182 and miRNA was validated by the dual-luciferase reporter and biotinylated RNA pull-down assays. Wnt/β-catenin pathway and epithelial-mesenchymal transition (EMT)-associated proteins were quantified by Western blot. Xenograft model was established for the research of circ_0082182 in vivo. Results Circ_0082182 was upregulated in CRC and could predict the poor prognosis of CRC patients. Functionally, circ_0082182 promoted CRC cell proliferation, cell cycle progression, and metastasis while inhibited apoptosis. Subsequently, circ_0082182 was shown to act as the sponges of miR-411 and miR-1205. MiR-411 and miR-1205 were identified as tumor inhibitors in CRC. Furthermore, circ_0082182 promoted the CRC progression via sponging miR-411 and miR-1205. Moreover, circ_0082182 facilitated the Wnt/β-catenin pathway and EMT process by targeting miR-411 and miR-1205. In vivo, circ_0082182 accelerated the CRC tumorigenesis and EMT process by activating the Wnt/β-catenin pathway by downregulating the expression of miR-411 or miR-1205. Conclusion This study showed that circ_0082182 functioned as an oncogene in the developing process of CRC by sponging miR-411 or miR-1205 to activate the Wnt/β-catenin pathway. Circ_0082182 might be a molecular target in the diagnosis and treatment of CRC.

scholarly journals Circ_0003998 enhances doxorubicin resistance in hepatocellular carcinoma by regulating miR-218-5p/EIF5A2 pathway

2020 ◽  
Vol 15 (1) ◽  
Author(s):  
Xiaomin Li ◽  
Jiefeng He ◽  
Xiaojing Ren ◽  
Haichao Zhao ◽  
Haoliang Zhao
Keyword(s):  
Hepatocellular Carcinoma ◽  
Cell Viability ◽  
Translation Initiation Factor ◽  
Cell Counting ◽  
Initiation Factor ◽  
Luciferase Reporter ◽  
Migration And Invasion ◽  
Circular Rnas ◽  
Reaction Cell

Abstract Background The involvement of circular RNAs (circRNAs) in chemoresistance of tumors has been identified. Herein, this study aims to investigate the role and the underlying mechanism of circ_0003998 in doxorubicin (DOX) resistance in hepatocellular carcinoma (HCC). Methods The expression of circ_0003998 and microRNA (miR)-218-5p and eukaryotic translation initiation factor 5A-2 (EIF5A2) mRNA was detected using quantitative real-time polymerase chain reaction. Cell viability, migration and invasion were analyzed using cell counting kit-8, colony formation and transwell assay, respectively. The levels of matrix metallopeptidase 9 (MMP-9), E-cadherin, Vimentin, N-cadherin and EIF5A2 protein were detected using western blot. The interaction between miR-218-5p and circ_0003998 or EIF5A2 was confirmed by dual-luciferase reporter assay. In vivo experiments were performed using murine xenograft models. Results Circ_0003998 was elevated in HCC tissues, DOX-resistant tissues and cells, and circ_0003998 knockdown promoted DOX-sensitivity in HCC by inhibiting resistant cell viability, migration, invasion and EMT in vitro and enhanced DOX cytotoxicity in vivo. Bioinformatics analysis revealed circ_0003998 inhibited miR-218-5p expression, which was clarified to be a target of circ_0003998, and circ_0003998 knockdown sensitized HCC cell to DOX by sponging miR-218-5p. EIF5A2 was a target of miR-218-5p, and miR-218-5p mitigated DOX resistance in HCC cells through modulating EIF5A2 expression. Additionally, circ_0003998 served as a competing endogenous RNA for miR-218-5p to regulate EIF5A2 expression. Conclusion Circ_0003998 knockdown sensitized HCC cell to DOX by regulating miR-218-5p/EIF5A2 axis, indicating new markers of poor response to DOX and potential therapeutic strategies for the chemotherapy of HCC.

scholarly journals Circular RNA circ_0081001 knockdown enhances methotrexate sensitivity in osteosarcoma cells by regulating miR-494-3p/TGM2 axis

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Wei Wei ◽  
Liefeng Ji ◽  
Wanli Duan ◽  
Jiang Zhu
Keyword(s):  
Cell Viability ◽  
Xenograft Model ◽  
Transglutaminase 2 ◽  
Circular Rna ◽  
Cell Counting ◽  
Luciferase Reporter ◽  
Migration And Invasion ◽  
Circular Rnas

Abstract Background Circular RNAs (circRNAs) have been shown to participate in the chemoresistance and tumorigenesis of multiple cancers. The purpose of this research was to investigate the function of circ_0081001 in methotrexate (MTX) resistance of osteosarcoma (OS) and its potential molecular mechanism. Methods The expression of circ_0081001, cytochrome P450 family 51 subfamily A member 1 (CYP51A1), and miR-494-3p was detected by qRT-PCR. Cell viability, apoptosis, migration, and invasion were evaluated by Cell Counting Kit-8 (CCK-8) assay, flow cytometry, and transwell assay, respectively. Western blot (WB) assay was used to measure the protein levels of cleaved-caspase3 (cleaved-casp3), E-cadherin, N-cadherin, and transglutaminase-2 (TGM2). The interaction between miR-494-3p and circ_0081001 or TGM2 was predicted by bioinformatics analysis and verified using the dual-luciferase reporter assay. The mice xenograft model was established to investigate the roles of circ_0081001 in MTX resistance of OS in vivo. Results Circ_0081001 and TGM2 were upregulated, and miR-494-3p was downregulated in MTX-resistant OS tissues and cells. Moreover, circ_0081001 interference enhanced cell sensitivity to MTX through promoting apoptosis and inhibiting cell viability and metastasis in vitro. Furthermore, circ_0081001 was identified as a molecular sponge of miR-494-3p to upregulate TGM2 level. In addition, circ_0081001 knockdown inhibited MTX resistance via upregulating miR-494-3p and downregulating TGM2. Besides, circ_0081001 downregulation improved MTX sensitivity of OS in vivo. Conclusion Knockdown of circ_0081001 enhanced MTX sensitivity of OS cells through downregulating TGM2 by sponging miR-494-3p, elucidating a novel regulatory mechanism for chemoresistance of OS and providing a potential circRNA-targeted therapy for OS.

scholarly journals circ_0000467 promotes the proliferation, metastasis, and angiogenesis in colorectal cancer cells through regulating KLF12 expression by sponging miR-4766-5p

Open Medicine ◽  
2021 ◽  
Vol 16 (1) ◽  
pp. 1415-1427
Author(s):  
Hui Chen ◽  
Chen Wu ◽  
Liang Luo ◽  
Yuan Wang ◽  
Fangxing Peng
Keyword(s):  
Colorectal Cancer ◽  
Cell Proliferation ◽  
Quantitative Polymerase Chain Reaction ◽  
Cell Counting ◽  
Luciferase Reporter ◽  
Migration And Invasion ◽  
Circular Rnas ◽  
Reaction Cell ◽  
Western Blot Assay

Abstract Background Circular RNAs have been identified as crucial players in the initiation and progression of cancers, including colorectal cancer (CRC). The Has_circ_0000467 (circ_0000467) expression has been found to be upregulated in CRC, but its function and mechanism remain unclear. Methods The expression levels of circ_0000467, microRNA-4766-5p (miR-4766-5p), and Krueppel-like factor 12 (KLF12) were examined using reverse transcription-quantitative polymerase chain reaction. Cell proliferation was analyzed by cell counting kit-8 assay and colony formation assay. The apoptosis was measured by flow cytometry. Transwell migration and invasion assays were applied to evaluate cell metastatic ability. Angiogenesis was detected using tube formation assay. All protein expressions were quantified by western blot assay. Dual-luciferase reporter assay was used to analyze intergenic binding. Xenograft models were constructed for the experiment of circ_0000467 in vivo. Results The expression of circ_0000467 was upregulated in CRC tissues and cells. Knockdown of circ_0000467 repressed cell proliferation, metastasis, and angiogenesis, but it induced apoptosis in CRC cells. circ_0000467 targeted miR-4766-5p and inhibited the expression of miR-4766-5p. Silencing of circ_0000467 inhibited CRC progression by upregulating miR-4766-5p. miR-4766-5p suppressed the expression of target gene KLF12 and KLF12 overexpression reversed the effects of miR-4766-5p on CRC cell behaviors. circ_0000467 positively regulated the expression of KLF12 by targeting miR-4766-5p. circ_0000467 downregulation in vivo reduced CRC tumorigenesis by regulating miR-4766-5p and KLF12. Conclusion circ_0000467 acted as an oncogene in CRC through regulating KLF12 expression by sponging miR-4766-5p. Therefore, circ_0000467 can be used as an effective target in CRC diagnosis and therapy.

scholarly journals CircRFX3 contributes to glioma progression through the circRFX3-miR-1179/miR-1229-VASP axis

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Hongli Li ◽  
Yiwei Zhang ◽  
Huiqin Song ◽  
Li Li
Keyword(s):  
Cell Proliferation ◽  
Glioma Cell ◽  
Xenograft Model ◽  
Tumor Promoter ◽  
Cell Counting ◽  
Luciferase Reporter ◽  
Migration And Invasion ◽  
Circular Rnas ◽  
Western Blot Assay

Abstract Background Circular RNAs (circRNAs) are implicated in the carcinogenesis of human cancers. However, the functional roles of circRFX3 in glioma are not elucidated. Methods Quantitative real-time polymerase chain reaction (qRT-PCR) assay was performed for the levels of circRFX3, RFX3, miR-1179, miR-1229 and vasodilator stimulated phosphoprotein (VASP). Actinomycin D assay and RNase R assay were employed to analyze the characteristics of circRFX3. Cell Counting Kit-8 (CCK-8) assay and colony formation assay were conducted for cell proliferation. Transwell assay was used for cell migration and invasion. Flow cytometry analysis was adopted for cell apoptosis. RNA pull-down assay, dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay were employed to analyze the interaction between miR-1179/miR-1229 and circRFX3 or VASP. Western blot assay was conducted for VASP protein level. Murine xenograft model assay was used to investigate the role of circRFX3 in vivo. Results CircRFX3 level was increased in glioma tissues and cells. Knockdown of circRFX3 suppressed glioma cell proliferation, migration and invasion and promoted apoptosis in vitro and repressed tumorigenesis of glioma in vivo. MiR-1179 and miR-1229 were identified to be the targets of circRFX3. MiR-1179 or miR-1229 inhibition reversed the impacts of circRFX3 knockdown on glioma cell malignant behaviors. Additionally, VASP was demonstrated to be the target gene of miR-1179 and miR-1229, and VASP overexpression abolished the effect of circRFX3 knockdown on glioma cell progression. Conclusion CircRFX3 served as a tumor promoter in glioma via modulating miR-1179/miR-1229-VASP axis, which might provide a novel target for glioma therapy.

scholarly journals LINC00202 promotes retinoblastoma progression by regulating cell proliferation, apoptosis, and aerobic glycolysis through miR-204-5p/HMGCR axis

2020 ◽  
Vol 15 (1) ◽  
pp. 437-448
Author(s):  
Aimin Wu ◽  
Xuewei Zhou ◽  
Linglong Mi ◽  
Jiang Shen
Keyword(s):  
Cell Proliferation ◽  
Noncoding Rna ◽  
Caspase 3 ◽  
Aerobic Glycolysis ◽  
Xenograft Model ◽  
Cell Counting ◽  
Luciferase Reporter ◽  
Reaction Cell

AbstractLINC00202 is a newly identified long noncoding RNA (lncRNA) and has been demonstrated to involve in the progression of retinoblastoma (RB). Here, we further explored the role and the underlying molecular mechanism of LINC00202 on RB malignant properties and glycolysis. LINC00202, microRNA (miR)-204-5p, and 3-hydroxy-3-methyl-glutaryl-coenzyme A reductase (HMGCR) mRNA were detected by a quantitative real-time polymerase chain reaction. Cell proliferation and apoptosis were analyzed using cell counting kit-8 assay and colony formation assay and flow cytometry, respectively. Glucose metabolism was calculated by measuring the extracellular acidification rate (ECRA). Western blot was used to detect the levels of HMGCR, ki67, pro-caspase-3, cleaved-caspase-3, and lactate dehydrogenase A chain (LDHA). The interaction between miR-204-5p and LINC00202 or HMGCR was analyzed by the dual-luciferase reporter assay. Murine xenograft model was established to conduct in vivo experiments. LINC00202 expression was upregulated in RB tumor tissues and LINC00202 knockdown inhibited RB cell proliferation, glycolysis, and stimulated apoptosis in vitro as well as impeded tumor growth in vivo. MiR-204-5p directly bound to LINC00202 and HMGCR in RB cells, and LINC00202 functioned as a competing endogenous RNA in regulating HMGCR through competitively binding to miR-204-5p. More importantly, the regulation of malignant properties and glycolysis of RB cells mediated by LINC00202 could be reversed by abnormal miR-204-5p or HMGCR expression in RB cells. In all, LINC00202 promoted RB cell proliferation, glycolysis, and suppressed apoptosis by regulating the miR-204-5p/HMGCR axis, suggesting a novel therapeutic target for patients with RB.

scholarly journals Warburg effect-promoted exosomal circ_0072083 releasing up-regulates NANGO expression through multiple pathways and enhances temozolomide resistance in glioma

2021 ◽  
Vol 40 (1) ◽  
Author(s):  
Chenyu Ding ◽  
Xuehan Yi ◽  
Xiangrong Chen ◽  
Zanyi Wu ◽  
Honghai You ◽  
...  
Keyword(s):  
Warburg Effect ◽  
Lactate Production ◽  
Xenograft Model ◽  
Cell Counting ◽  
Luciferase Reporter ◽  
Migration And Invasion ◽  
Circular Rnas ◽  
Rna Immunoprecipitation ◽  
Resistant Cells

Abstract Background Temozolomide (TMZ) resistance limits its application in glioma. Exosome can carry circular RNAs (circRNAs) to regulate drug resistance via sponging microRNAs (miRNAs). miRNAs can control mRNA expression by regulate the interaction with 3’UTR and methylation. Nanog homeobox (NANOG) is an important biomarker for TMZ resistance. Hitherto, it is unknown about the role of exosomal hsa_circ_0072083 (circ_0072083) in TMZ resistance in glioma, and whether it is associated with NANOG via regulating miRNA sponge and methylation. Methods TMZ-resistant (n = 36) and sensitive (n = 33) patients were recruited. The sensitive cells and constructed resistant cells were cultured and exposed to TMZ. circ_0072083, miR-1252-5p, AlkB homolog H5 (ALKBH5) and NANOG levels were examined via quantitative reverse transcription polymerase chain reaction and western blot. The half maximal inhibitory concentration (IC50) of TMZ, cell proliferation, apoptosis, migration and invasion were analyzed via Cell Counting Kit-8, colony formation, flow cytometry, wound healing and transwell assays. The in vivo function was assessed using xenograft model. The N6-methyladenosine (m6A) level was analyzed via methylated RNA immunoprecipitation (MeRIP). Target relationship was investigated via dual-luciferase reporter assay and RNA immunoprecipitation. Warburg effect was investigated via lactate production, glucose uptake and key enzymes expression. Exosome was isolated and confirmed via transmission electron microscopy and specific protein expression. Results circ_0072083 expression was increased in TMZ-resistant glioma tissues and cells. circ_0072083 knockdown restrained the resistance of resistant cells via decreasing IC50 of TMZ, proliferation, migration, invasion and xenograft tumor growth and increasing apoptosis. circ_0072083 silence reduced NANOG expression via blocking ALKBH5-mediated demethylation. circ_0072083 could regulate NANOG and ALKBH5 via targeting miR-1252-5p to control TMZ resistance. Warburg effect promoted the release of exosomal circ_0072083 in resistant cells. Exosomal circ_0072083 from resistant cells increased the resistance of sensitive cells to TMZ in vitro and xenograft model. Exosomal circ_0072083 level was enhanced in resistant patients, and it had a diagnostic value and indicated a lower overall survival in glioma. Conclusion Exosomal circ_0072083 promoted TMZ resistance via increasing NANOG via regulating miR-1252-5p-mediated degradation and demethylation in glioma.

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