scholarly journals Exosome-Mediated Transfer of circ_0000338 Enhances 5-Fluorouracil Resistance in Colorectal Cancer through Regulating MicroRNA 217 (miR-217) and miR-485-3p

2021 ◽  
Vol 41 (5) ◽  
Author(s):  
Kui Zhao ◽  
Xiaohui Cheng ◽  
Zhenyu Ye ◽  
Yecheng Li ◽  
Wei Peng ◽  
...  

ABSTRACT Exosomes are microvesicles secreted by body cells for intercellular communication. The circular RNA circ_0000338 was found to be present in extracellular vesicles and improve the chemoresistance of colorectal cancer (CRC) cells. However, the role of exosomal circ_0000338 in 5-fluorouracil (5-FU) resistance in CRC is largely unknown. The levels of circ_0000338, microRNA 217 (miR-217), and miR-485-3p were detected using quantitative real-time PCR (qRT-PCR). The 50% inhibitory concentration (IC50) values of cells for 5-FU, cell proliferation, and apoptosis were evaluated using cell counting kit 8 (CCK-8), colony formation, flow cytometry, and Western blot assays. The interaction between miR-217 or miR-485-3p and circ_0000338 was confirmed by RNA immunoprecipitation (RIP), dual-luciferase reporter, and pulldown assays. Exosomes were isolated by ultracentrifugation and qualified by transmission electron microscopy (TEM), Nanosight tracking analysis (NTA), and Western blotting. Xenograft models were performed to analyze whether circ_0000338-loaded exosomes could increase resistance of CRC cells to 5-FU in vivo. The circ_0000338 level was elevated in 5-FU-resistant CRC tissues and cells, and circ_0000338 knockdown sensitized 5-FU-resistant CRC cells to 5-FU through enhancing apoptosis and decreasing proliferation in vitro. Mechanistically, circ_0000338 directly bound to miR-217 and miR-485-3p, and the inhibition of miR-217 or miR-485-3p reversed the effects of circ_0000338 knockdown on cell 5-FU resistance in CRC. Additionally, extracellular circ_0000338 could be incorporated into secreted exosomes and transmitted to 5-FU-sensitive cells. Treatment-sensitive cells with exosomes containing circ_0000338 reduced the 5-FU response in CRC both in vitro and in vivo. Besides that, the exosomal circ_0000338 concentration was higher in patients exhibiting resistance to 5-FU and showed good diagnostic efficiency in 5-FU-resistant CRC. The delivery of circ_0000338 via exosomes enhanced 5-FU resistance in CRC through negative regulation of miR-217 and miR-485-3p, indicating a promising diagnostic and therapeutic marker for 5-FU-based chemotherapy in CRC patients.

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Jiaqi Wang ◽  
Yi Zhang ◽  
Hu Song ◽  
Hang Yin ◽  
Tao Jiang ◽  
...  

Abstract Background Noncoding RNAs such as circular RNAs (circRNAs) are abundant in the human body and influence the occurrence and development of various diseases. However, the biological functions of circRNAs in colorectal cancer (CRC) are largely unknown. Methods RT-qPCR was used to detect the expression of circRNAs and mRNA in CRC cells and tissues. Fluorescence in situ hybridization (FISH) was used to analyze the location of circSPARC. Function-based experiments were performed using circSPARC knockdown and overexpression cell lines in vitro and in vivo, including CCK8, colony formation, transwell and metastasis models. Mechanistically, luciferase reporter assay, western blots, RNA immunoprecipitation (RIP), Chromatin isolation by RNA purification (ChIRP) and immunohistochemical stainings were performed. Results CircSPARC was upregulated in both the tissues and plasma of CRC patients. High expression of circSPARC was associated with advanced TNM stage, lymph node metastases, and poor survival. Silencing circSPARC inhibited CRC cell migration and proliferation in vitro and vivo. Mechanistically, circSPARC sponged miR-485-3p to upregulate JAK2 expression and ultimately contribute to the accumulation of phosphorylated (p)-STAT3. Besides, circSPARC recruited FUS, which facilitated the nuclear translocation of p-STAT3. Conclusions These findings suggest that circSPARC might serve as a potential diagnostic and prognostic biomarker and a therapeutic target for CRC treatment by regulating JAK2/STAT3 pathway.


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Lanlan Xi ◽  
Quanlin Liu ◽  
Wei Zhang ◽  
Linshan Luo ◽  
Jingfeng Song ◽  
...  

Abstract Background Circular RNAs (circRNAs) have been reported to play vital roles in colorectal cancer (CRC). However, only a few circRNAs have been experimentally validated and functionally described. In this research, we aimed to reveal the functional mechanism of circCSPP1 in CRC. Methods 36 DOX sensitive and 36 resistant CRC cases participated in this study. The expression of circCSPP1, miR-944 and FZD7 were detected by quantitative real time polymerase chain reaction (qRT-PCR) and the protein levels of FZD7, MRP1, P-gp and LRP were detected by western blot. Cell proliferation, migration, invasion, and apoptosis were assessed by 3-(4, 5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2-H-tetrazolium bromide (MTT) assay, transwell assay, or flow cytometry analysis, respectively. The interaction between miR-944 and circCSPP1 or frizzled-7 (FZD7) was predicted by Starbase 3.0 and verified by the dual luciferase reporter assay, RNA immunoprecipitation (RIP) assay and RNA pull down assay. Xenograft tumor assay was performed to examine the effect of circCSPP1 on tumor growth in vivo. Results The expression of circCSPP1 and FZD7 was upregulated while miR-944 expression was downregulated in doxorubicin (DOX)-resistant CRC tissues and cells. CircCSPP1 knockdown significantly downregulated enhanced doxorubicin sensitivity, suppressed proliferation, migration, invasion, and induced apoptosis in DOX-resistant CRC cells. Interestingly, we found that circCSPP1 directly downregulated miR-944 expression and miR-944 decreased FZD7 level through targeting to 3′ untranslated region (UTR) of FZD7. Furthermore, circCSPP1 mediated DOX-resistant CRC cell progression and doxorubicin sensitivity by regulating miR-944/FZD7 axis. Besides, circCSPP1 downregulation dramatically repressed CRC tumor growth in vivo. Conclusion Our data indicated that circCSPP1 knockdown inhibited DOX-resistant CRC cell growth and enhanced doxorubicin sensitivity by miR-944/FZD7 axis, providing a potential target for CRC therapy.


2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Nan Wang ◽  
Jia-Xing He ◽  
Guo-Zhan Jia ◽  
Ke Wang ◽  
Shuai Zhou ◽  
...  

Abstract Background Recent studies suggest that long noncoding RNAs (lncRNAs) play an important role in tumorigenesis. As a newly identified lncRNA, the role of XIST in colorectal cancer (CRC) has not been established. Here, we sought to characterize the role of XIST and its associated regulatory network in CRC cells. Methods Expression of XIST mRNA, miR-497-5p, and forkhead box k1 (FOXK1) in CRC cells and tissues were detected using quantitative real-time polymerase chain reaction (qRT-PCR). Proliferation and apoptosis of CRC cells were determined using the CCK-8 cell counting assay and flow cytometry. The rate of cell migration and invasion was determined using a transwell assay. The relationships between XIST, miR-497-5p, and FOXK1 were predicted and confirmed using a dual-luciferase reporter assay. Expression of FOXK1 protein was quantified by Western blot. Results XIST and FOXK1 expression were significantly upregulated in CRC tissues and cell lines, while miR-497-5p expression was downregulated. XIST knockdown significantly suppressed CRC cell proliferation, migration, and invasion. Silencing of XIST also reversed the downregulation of miR-497-5p and upregulation of FOXK1. Moreover, blocking XIST expression was shown to inhibit CRC tumor growth in vivo and the effects were antagonized by the loss of miR-497-5p. miR-497-5p was shown to act as a sponge of XIST and also targeted FOXK1 in CRC cells. Conclusions XIST was shown to promote the malignancy of CRC cells by competitively binding to miR-497-5p, resulting in an increase in FOXK1 expression. These results suggest that targeting of XIST may represent a possible treatment for CRC.


2020 ◽  
Author(s):  
Peng Shen ◽  
Lili Qu ◽  
Jingjing Wang ◽  
Quchen Ding ◽  
Chuanwen Zhou ◽  
...  

Abstract Background Long intergenic non-protein coding RNA 342 (LINC00342) has been identified as a novel oncogene, however, the functional role of LINC00342 in colorectal cancer (CRC) remained unclear. Methods The expression of LINC00342 was detected by real-time PCR. Cell proliferation, migration and invasion and xenograft model were examined to analyze the biological functions of LINC00342 in vitro and in vivo. Dual-luciferase reporter and RNA immunoprecipitation (RIP) assays were used to identify the target interactions between LINC00342, miR-19a-3p and aminopeptidase like 1 (NPEPL1). Results LINC00342 was highly expressed in CRC. Downregulation of LINC00342 inhibited cell proliferation and metastasis of CRC cells. Moreover, knocking down LINC00342 could weaken the tumor growth in vivo. Mechanistic investigation revealed that LINC00342 may sponge miR-19a-3p to regulate NPEPL1 expression. Further investigation indicated that the oncogenesis facilitated by LINC00342 was inhibited by NPEPL1 depletion.Conclusion LINC00342 promoted CRC progression by competitively binding miR-19a-3p with NPEPL1.


Author(s):  
Yipei Jing ◽  
Xueke Jiang ◽  
Li Lei ◽  
Meixi Peng ◽  
Jun Ren ◽  
...  

Abstract Background Acute myeloid leukemia (AML) with mutated nucleophosmin (NPM1), which displays a distinct long noncoding RNA (lncRNA) expression profile, has been defined as a unique subgroup in the new classification of myeloid neoplasms. However, the biological roles of key lncRNAs in the development of NPM1-mutated AML are currently unclear. Here, we aimed to investigate the functional and mechanistic roles of the lncRNA HOTAIRM1 in NPM1-mutated AML. Methods The expression of HOTAIRM1 was analyzed with a public database and further determined by qRT-PCR in NPM1-mutated AML samples and cell lines. The cause of upregulated HOTAIRM1 expression was investigated by luciferase reporter, chromatin immunoprecipitation and ubiquitination assays. The functional role of HOTAIRM1 in autophagy and proliferation was evaluated using western blot analysis, immunofluorescence staining, a Cell Counting Kit-8 (CCK-8) assay, a 5-ethynyl-2′-deoxyuridine (EdU) incorporation assay, flow cytometric analyses and animal studies. The action mechanism of HOTAIRM1 was explored through RNA fluorescence in situ hybridization, RNA pulldown and RNA immunoprecipitation assays. Results HOTAIRM1 was highly expressed in NPM1-mutated AML. High HOTAIRM1 expression was induced in part by mutant NPM1 via KLF5-dependent transcriptional regulation. Importantly, HOTAIRM1 promoted autophagy and proliferation both in vitro and in vivo. Mechanistic investigations demonstrated that nuclear HOTAIRM1 promoted EGR1 degradation by serving as a scaffold to facilitate MDM2-EGR1 complex formation, while cytoplasmic HOTAIRM1 acted as a sponge for miR-152-3p to increase ULK3 expression. Conclusions Taken together, our findings identify two oncogenic regulatory axes in NPM1-mutated AML centered on HOTAIRM1: one involving EGR1 and MDM2 in the nucleus and the other involving the miR-152-3p/ULK3 axis in the cytoplasm. Our study indicates that HOTAIRM1 may be a promising therapeutic target for this distinct leukemia subtype.


2020 ◽  
Author(s):  
Dianqi Hou ◽  
Zhenlin Wang ◽  
Haimeng Li ◽  
Juan Liu ◽  
Yaohua Liu ◽  
...  

Abstract background: Glioblastoma Multiform (GBM) is the primary malignancy with the highest incidence and worst prognosis in the adult CNS. Circular RNAs (circRNAs) are a novel and widely diverse class of endogenous non-coding RNAs that can promote or inhibit gliomagenesis. Our study aimed to explore the role of circASPM in GBM and its molecular mechanism.Methods: Levels of circASPM, miR-130b-3p and E2F1 were determined by quantitative real-time PCR (qRT-PCR) or western blotting assay. MTS, Edu, neurospheres formation and extreme limiting dilution assays were used to detect the tumorigenesis and proliferation of GSCs in vitro. The interactions between miR-130b-3p and circASPM or E2F1 was demonstrated via qPCR, western blotting, dual-luciferase reporter and RNA immunoprecipitation (RIP) assays. Xenograft experiments was used to analyze tumor growth in vivo.Results: CircASPM was overexpressed in GBM and could promote the tumorigenesis and proliferation of GSCs both in vitro and in vivo. Mechanistically, circASPM up-regulated the expression of E2F1 in GSCs via miR-130b-3p sponging. We furtherly demonstrated that circAPSM could promote the GSCs proliferation via E2F1 up-regulating. Therefore, our study identified a novel circRNA and its possible mechanism in the development and tumorigenesis of GBM.Conclusions: CircASPM can promote GBM progression via regulating miR-130b-3p/E2F1 axis, suggesting that circAPSM could provide an effective biomarker for GBM diagnosis and prognostic evaluation and possibly being used for molecular targeted therapy.


2022 ◽  
Vol 13 (1) ◽  
Author(s):  
Lei Zhang ◽  
Jing Zhang ◽  
Pengfei Li ◽  
Ting Li ◽  
Zhiqin Zhou ◽  
...  

AbstractMacrophage-derived exosomes (Mφ-Exo) have multidimensional involvement in tumor initiation, progression, and metastasis, but their regulation in hepatocellular carcinoma (HCC) is not fully understood. RBPJ has been implicated in macrophage activation and plasticity. In this study we assess the role of exosomes derived from RBPJ-overexpressed macrophages (RBPJ+/+ Mφ-Exo) in HCC. The circular RNA (circRNA) profiles in RBPJ+/+ Mφ-Exo and THP-1-like macrophages (WT Mφ)-Exo was evaluated using circRNA microarray. CCK-8, Transwell, and flow cytometry analyses were used to evaluate the function of Mφ-Exo-circRNA on HCC cells. Luciferase reporter assays, RNA immunoprecipitation, and Pearson’s correlation analysis were used to confirm interactions. A nude mouse xenograft model was used to further analyze the functional significance of Mφ-Exo-cirRNA in vivo. Our results shown that hsa_circ_0004658 is upregulated in RBPJ+/+ Mφ-Exo compared to WT Mφ-Exo. RBPJ+/+ Mφ-Exo and hsa_circ_0004658 inhibits proliferation and promotes apoptosis in HCC cells, whereas hsa_circ_0004658 knockdown stimulated cell proliferation and migration but restrained apoptosis in vitro and promotes tumor growth in vivo. The effects of RBPJ+/+ Mφ-Exo on HCC cells can be reversed by the hsa_circ_0004658 knockdown. Mechanistic investigations revealed that hsa_circ_0004658 acts as a ceRNA of miR-499b-5p, resulting in the de-repression of JAM3. These results indicate that exosome circRNAs secreted from RBPJ+/+ Mφ inhibits tumor progression through the hsa_circ_0004658/miR-499b-5p/JAM3 pathway and hsa_circ_0004658 may be a diagnostic biomarker and potential target for HCC therapy.


2020 ◽  
Vol 15 (1) ◽  
pp. 848-859
Author(s):  
Wei Wei ◽  
Liefeng Ji ◽  
Wanli Duan ◽  
Jiang Zhu

AbstractCircular RNA sterile alpha motif domain containing 4A (circSAMD4A) was found to be differentially expressed in osteosarcoma and contributed to the tumorigenesis of osteosarcoma. However, the role of circSAMD4A in doxorubicin (DXR) resistance of osteosarcoma is yet to be elucidated. Levels of circSAMD4A, microRNA (miR)-218-5p and Krüppel-like factor 8 (KLF8) were detected using quantitative reverse transcription-polymerase chain reaction. Western blot was applied to detect the protein levels of KLF8, cyclin D1 and p21. Cell viability, cell cycle, migration and invasion were analyzed using Cell Counting Kit-8 assay, flow cytometry and transwell assay, respectively. The interaction between miR-218-5p and circSAMD4A or KLF8 was verified using dual-luciferase reporter assay or RNA immunoprecipitation assay. In vivo experiments were performed using murine xenograft models. CircSAMD4A and KLF8 were elevated in osteosarcoma, and knockdown of circSAMD4A or KLF8 sensitized osteosarcoma cells to DXR by mediating resistant cell viability, migration and invasion inhibition, and cell cycle arrest in vitro. miR-218-5p was decreased in osteosarcoma, and miR-218-5p inhibition enhanced DXR resistance. Besides, miR-218-5p was found to bind to circSAMD4A or KLF8, and subsequent rescue experiments indicated that miR-218-5p inhibition reversed the inhibitory effects of circSAMD4A silencing on DXR resistance, and silencing miR-218-5p enhanced DXR resistance by targeting KLF8 in osteosarcoma cells. Moreover, circSAMD4A could indirectly regulate KLF8 via miR-218-5p. Additionally, circSAMD4A knockdown enhanced the cytotoxicity of DXR in osteosarcoma in vivo via regulating miR-218-5p and KLF8. In all, circSAMD4A enhanced cell DXR resistance in osteosarcoma by regulating the miR-218-5p/KLF8 axis, suggesting a novel therapeutic target for therapy-resistant osteosarcoma.


2020 ◽  
Author(s):  
Jun Liu ◽  
Wenshuai Zhu ◽  
Jianqin Ji

Abstract Background Osteosarcoma (OS) is a common aggressive primary sarcoma of bone. Drug resistance is a huge obstacle to chemotherapy for cancer. This study aimed to investigate the role and mechanism of circ_0002060 in OS resistance to doxorubicin (DOX). Methods The levels of circ_0002060, miR-198 and ATP binding cassette subfamily B member 1 (ABCB1) were measured by quantitative real-time polymerase chain reaction or western blot assay. Kaplan-Meier analysis was performed to determine the relationship between circ_0002060 expression and overall survival. The half inhibition concentration (IC50) of doxorubicin was calculated by Cell Counting Kit-8 (CCK-8) assay. Cell proliferation was assessed by colony formation assay. Cell apoptosis was monitored by flow cytometry. The levels of apoptosis-related proteins were measured by western blot assay. Xenograft assay was utilized to analyze the effect of circ_0002060 on DOX resistance in vivo . The interaction among circ_0002060, miR-198 and ABCB1 were confirmed by dual-luciferase reporter assay, RNA immunoprecipitation assay or RNA pull-down assay. Results Circ_0002060 and ABCB1 were up-regulated, while miR-198 was down-regulated in OS tissues and DOX-resistant OS cells. Circ_0002060 silence reduced DOX resistance in vitro and in vivo . Moreover, circ_0002060 enhanced DOX resistance via sponging miR-198. Besides, miR-198 decreased DOX resistance by binding to ABCB1. In addition, circ_0002060 sponged miR-198 to up-regulate ABCB1 expression. Conclusion Circ_0002060 enhanced doxorubicin resistance of OS by regulating miR-198/ABCB1 axis, which provides potential therapeutic targets for OS therapy.


2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Linfei Huang ◽  
Lei Zhu ◽  
Sheng Pan ◽  
Jing Xu ◽  
Miao Xie ◽  
...  

Abstract Background Circular RNA 0029803 (circ_0029803) was found to be upregulated in colorectal cancer (CRC) tissues, but its function and underlying molecular mechanism are not studied in CRC. Methods The expression levels of circ_0029803, microRNA-216b-5p (miR-216b-5p), and ski-oncogene-like (SKIL) were measured by quantitative real-time polymerase chain reaction (qRT-PCR). RNase R treatment was used to affirm the existence of circ_0029803. Cell proliferation, apoptosis, migration, and invasion were assessed by colony formation, flow cytometry, and Transwell assays, respectively. A glucose and lactate assay kit was used to detect glucose consumption and lactate production. Western blot was applied to analyze the levels of all proteins. Dual-luciferase reporter assay was performed to assess the relationship between miR-216b-5p and circ_0029803 or SKIL. Tumor xenograft models were established to elucidate the effect of circ_0029803 in vivo. Results Circ_0029803 expression was enhanced in CRC tissues and cells, and the 5-year overall survival rate of patients with high circ_0029803 expression was substantially reduced. Circ_0029803 depletion retarded proliferation, migration, invasion, EMT and glycolysis of CRC cells in vitro as well as the tumor growth in vivo. Mechanically, circ_0029803 could serve as miR-216b-5p sponge to regulate its expression, and miR-216b-5p knockdown reversed the inhibition of si-circ_0029803 on the malignant behaviors of CRC cells. Additionally, as the target mRNA of miR-216b-5p, SKIL could counteract the inhibitory effect of miR-216b-5p on the development of CRC cells. Importantly, silencing circ_0029803 reduced SKIL expression via sponging miR-216b-5p. Conclusion Circ_0029803 knockdown hindered proliferation, migration, invasion, EMT, and glycolysis and promoted apoptosis in CRC cells by modulating the miR-216b-5p/SKIL axis.


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