scholarly journals LncRNA SNHG6 promotes chemoresistance through ULK1-induced autophagy by sponging miR-26a-5p in colorectal cancer cells

2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Xinke Wang ◽  
Zhixian Lan ◽  
Juan He ◽  
Qiuhua Lai ◽  
Xiang Yao ◽  
...  

Abstract Background Chemotherapy resistance is one of the main causes of recurrence in colorectal cancer (CRC) patients and leads to poor prognosis. Long noncoding RNAs (lncRNAs) have been reported to regulate chemoresistance. We aimed to determine the role of the lncRNA small nucleolar RNA host gene 6 (SNHG6) in CRC cell chemoresistance. Methods Cell drug sensitivity tests and flow cytometry were performed to analyze CRC cell chemoresistance. Animal models were used to determine chemoresistance in vivo, and micro RNA (miRNA) binding sites were detected by dual-luciferase reporter assays. Bioinformatics analysis was performed to predict miRNAs binding to SNHG6 and target genes of miR-26a-5p. SNHG6/miR-26a-5p/ULK1 axis and autophagy-related proteins were detected by qRT-PCR and western blotting. Furthermore, immunofluorescence was employed to confirm the presence of autophagosomes. Results SNHG6 enhanced CRC cell resistance to 5-fluorouracil (5-FU), promoted autophagy, inhibited 5-FU-induced apoptosis, and increased 5-FU resistance in vivo. Bioinformatics analysis showed that miR-26a-5p might bind to SNHG6 and target ULK1, and dual-luciferase reporter assays confirmed this activity. qRT-PCR and western blotting showed that SNHG6 was able to negatively regulate miR-26a-5p but correlated positively with ULK1. Conclusion SNHG6 may promote chemoresistance through ULK1-induced autophagy by sponging miR-26a-5p in CRC cells.

2018 ◽  
Vol 51 (1) ◽  
pp. 113-128 ◽  
Author(s):  
Jia Zhu ◽  
Rui Zhang ◽  
Dongxiang Yang ◽  
Jibin Li ◽  
Xiaofei Yan ◽  
...  

Background/Aims: Doxorubicin (DOX) is a widely used chemotherapeutic agent for colorectal cancer (CRC). However, the acquirement of DOX resistance limits its clinical application for cancer therapy. Mounting evidence has suggested that aberrantly expressed lncRNAs contribute to drug resistance of various tumors. Our study aimed to explore the role and molecular mechanisms of lncRNA X-inactive specific transcript (XIST) in chemoresistance of CRC to DOX. Methods: The expressions of XIST, miR-124, serum and glucocorticoid-inducible kinase 1 (SGK1) mRNA in DOX-resistant CRC tissues and cells were detected by qRT-PCR or western blot analysis. DOX sensitivity was assessed by detecting IC50 value of DOX, the protein levels of P-glycoprotein (P-gp) and glutathione S-transferase-π (GST-π) and apoptosis. The interactions between XIST, miR-124 and SGK1 were confirmed by luciferase reporter assay, qRT-PCR and western blot. Xenograft tumor assay was used to verify the role of XIST in DOX resistance in CRC in vivo. Results: XIST expression was upregulated and miR-124 expression was downregulated in DOX-resistant CRC tissues and cells. Knockdown of XIST inhibited DOX resistance of CRC cells, as evidenced by the reduced IC50 value of DOX, decreased P-gp and GST-π levels and enhanced apoptosis in XIST-silenced DOX-resistant CRC cells. Additionally, XIST positively regulated SGK1 expression by interacting with miR-124 in DOX-resistant CRC cells. miR-124 suppression strikingly reversed XIST-knockdown-mediated repression on DOX resistance in DOX-resistant CRC cells. Moreover, SGK1-depletion-elicited decrease of DOX resistance was greatly restored by XIST overexpression or miR-124 inhibition in DOX-resistant CRC cells. Furthermore, XIST knockdown enhanced the anti-tumor effect of DOX in CRC in vivo. Conclusion: XIST exerted regulatory function in resistance of DOX possibly through miR-124/SGK1 axis, shedding new light on developing promising therapeutic strategy to overcome chemoresistance in CRC patients.


Author(s):  
Baochi Ou ◽  
Hongze Sun ◽  
Jingkun Zhao ◽  
Zhuoqing Xu ◽  
Yuan Liu ◽  
...  

Abstract Background Polo-like kinase 3 (PLK3) has been documented as a tumor suppressor in several types of malignancies. However, the role of PLK3 in colorectal cancer (CRC) progression and glucose metabolism remains to be known. Methods The expression of PLK3 in CRC tissues was determined by immunohistochemistry. Cells proliferation was examined by EdU, CCK-8 and in vivo analyses. Glucose metabolism was assessed by detecting lactate production, glucose uptake, mitochondrial respiration, extracellular acidification rate, oxygen consumption rate and ATP production. Chromatin immunoprecipitation, luciferase reporter assays and co-immunoprecipitation were performed to explore the signaling pathway. Specific targeting by miRNAs was determined by luciferase reporter assays and correlation with target protein expression. Results PLK3 was significantly downregulated in CRC tissues and its low expression was correlated with worse prognosis of patients. In vitro and in vivo experiments revealed that PLK3 contributed to growth inhibition of CRC cells. Furthermore, we demonstrated that PLK3 impeded glucose metabolism via targeting Hexokinase 2 (HK2) expression. Mechanically, PLK3 bound to Heat shock protein 90 (HSP90) and facilitated its degradation, which led to a significant decrease of phosphorylated STAT3. The downregulation of p-STAT3 further suppressed the transcriptional activation of HK2. Moreover, our investigations showed that PLK3 was directly targeted by miR-106b at post-transcriptional level in CRC cells. Conclusion This study suggests that PLK3 inhibits glucose metabolism by targeting HSP90/STAT3/HK2 signaling and PLK3 may serve as a potential therapeutic target in colorectal cancer.


2021 ◽  
Vol 12 ◽  
Author(s):  
Xinzhuan Jia ◽  
Lan Wei ◽  
Zhengmao Zhang

BackgroundAccumulated studies have reported that dysregulated long non-coding RNAs (lncRNAs) are crucial in ovarian cancer (OC) initiation and development. However, detailed biological functions of lncRNA NEAT1 during the progression of OC remains to be uncovered.PurposeOur aim was to identify the role of NEAT1 in cisplatin resistance of ovarian cancer and the underlying mechanisms.MethodsThe expression patterns of NEAT1 in OC cell lines and tissue samples were identified by qRT-PCR. The cisplatin (DDP) sensitivity of OC cells was detected by MTT and CCK8 assay, while OC cell apoptosis and cell cycle were detected using flow cytometer assays. In addition, effects of NEAT1 on tumor growth were determined by xenograft tumor model. Luciferase reporter assay was conducted to prove the regulatory relation of miR-491-5p, NEAT1, and SOX3. Importantly, the expression of NEAT1 in exosomes from cisplatin-resistant patients was also determined by using qRT-PCR.ResultsIn this study, upregulated NEAT1 was detected in OC cell lines and tissues. Meanwhile, NEAT1 was also increased in cisplatin-resistant OC cell lines and tissues. Upregulation of NEAT1 inhibited cisplatin-induced OC cell apoptosis and promoted cell proliferation, while knockdown of NEAT1 played the opposite role. These effects were also observed in vivo. Furthermore, direct interaction was observed between NEAT1 and miR-491-5p. NEAT1 led to the upregulation of miR-491-5p-targeted SOX3 mRNA. Importantly, this study also showed upregulated NEAT1 expression in serum exosomes derived from cisplatin-resistant patients.ConclusionNEAT1 is vital in the chemoresistance of ovarian cancer through regulating miR-491-5p/SOX3 pathway, showing that NEAT1 might be a potential target for OC resistance treatment.


2021 ◽  
Vol 65 (4) ◽  
Author(s):  
Yang Liu ◽  
Weichun Guo ◽  
Shuo Fang ◽  
Bin He ◽  
Xiaohai Li ◽  
...  

Osteosarcoma (OS), characterized by high morbidity and mortality, is the most common bone malignancy worldwide. MicroRNAs (miRNAs) play a crucial role in the initiation and development of OS. The purpose of this study was to investigate the roles of miR-1270 in OS. RT-qPCR and Western blot were applied to detect the mRNA and protein level, respectively. CCK-8, colony formation, and TUNEL assays were conducted to determine the cell viability, proliferation, and apoptosis of OS cells. Wound healing and transwell assay were performed to detect the migration and invasion ability of OS cells. Bioinformatics analysis and dual-luciferase reporter assay were used to predict the target genes of miR-1270. Tumor xenograft in vivo assay was carried out to determine miR-1270 effect on the tumor size, volume, and weight. In this study, miR-1270 was overexpressed in OS tissues and cells. However, miR-1270 knockdown inhibited the proliferation, migration and invasion, and promoted the OS cells’ apoptosis. Mechanistically, cingulin (CGN) was predicted and proved to be a target of miR-1270 and partially alleviated the effects of miR-1270 on the proliferation, migration and invasion ability of OS cells. Taken together, knockdown of miR-1270 may inhibit the development of OS via targeting CGN. This finding may provide a novel therapeutic strategy for OS.


2021 ◽  
Author(s):  
Hong Liang ◽  
Qiuyan Zhao ◽  
Zhonglin Zhu ◽  
Chao Zhang ◽  
Hui Zhang

Abstract Background: Long non-coding RNAs (lncRNAs) have been elucidated to participate in the development and progression of various cancers. In this study, we aim to explore the underlying functions and mechanisms of LINC00958 in colorectal cancer. Methods: LINC00958 expression in colorectal cancer tissues was examined by qRT-PCR. The associations between LINC00958 expression with clinical characteristics and prognosis were evaluated. The biological functions of LINC00958 were detected by CCK-8, MTT, colony formation and Flow cytometric analyses. RNA-pull down, RIP and luciferase reporter assays were used to confirm the regulation of LINC00958 on miR-422a. Rescue experiments were performed to detect the effects of miR-422a on the roles of LINC00958. Results: LINC00958 was upregulated in colorectal cancer tissues and cell lines; high LINC00958 level was significantly associated with tumor differentiation, T stage and TNM stage, and also predicted poor prognosis. Cell experiments showed that LINC00958 promoted cell proliferation and suppressed apoptosis and the sensitivity of radiotherapy in vitro, and promoted cell growth in vivo. Bioinformatics analysis predicted the binding site of miR-422a on LINC00958. Mechanistically, RNA-pull down, RIP and luciferase reporter assays demonstrated that LINC00958 specially targeted miR-422a. In addition, we provided evidence that miR-422a suppressed MAPK1 expression through directly binding to the 3’-UTR of MAPK1, thereby inhibiting cell proliferation and enhancing apoptosis and the radiosensitivity. Furthermore, miR-422a rescued the roles of LINC00958 on promoting MAPK1 expression and cell proliferation and decreasing apoptosis and the radiosensitivity. Conclusions: LINC00958 promoted MAPK1 expression and cell proliferation and suppressed apoptosis and the radiosensitivity through targeting miR-422a, highlighting a potential biomarker for the prognosis and treatment of colorectal cancer.


Stroke ◽  
2020 ◽  
Vol 51 (Suppl_1) ◽  
Author(s):  
DaZhi Liu

MicroRNAs(miRs)are very promising next generation drug targets due to their unique miR-target binding that is different from the traditional ligand-receptor. A single miR binds to complementary bases in the 3’ untranslated regions(3’UTR) of hundreds of target genes and down-regulates these genes. MiR therapeutics have been developed for treatment of various diseases, with several miR drugs(e.g., miR-122/miR-155 inhibitors, miR-16/29/34 mimics) being advanced into human trials in the last decade. Our previous studies showed that intravenous (i.v.) miR-122 mimic (2.4mg/kg, wrapped in PEG-liposomes) improves outcomes after suture middle cerebral artery occlusion(MCAO)-induced ischemic stroke (IS) with a 6 hour time window. In pilot whole genome miR expression studies, we demonstrated that microRNA-122 (miR-122) is the most significantly decreased miR in blood after intraventricularautologousfresh blood-induced intracerebral hemorrhage (ICH) in rats. As compared to sham controls, miR-122 decreased 28 fold at 3 hrs, 34 fold at 24 hrs, 31 fold at 7 days and 19 fold at 14 days in blood after ICH in rats. These miRNA expression data suggest that elevating miR-122 in blood has great potential to treat ICH in addition to IS. Therefore, we hypothesized that i.v. miR-122 mimic improves outcomes after ICH, in addition to IS. Our miR-122 targetome studies show that a set of miR-122 target genes (Pla2g2a, Vcam1, Nos2, Rhbdf1, Olig1, Nrep) are responsible for the therapeutic efficacy of miR-122 mimic on ischemic stroke, while another set of genes (Ywhaq, Klrk1, Tpst1, Vars2)account for efficacy in ICH. Using3’UTR luciferase reporter assays and anti-sense Morpholino Oligos (MOs), we show that miR-122 binds to 3’UTR of its target genes Pla2g2a and Vcam1, rather than Nos2. In addition, in vivo MO-miR-122-Pla2g2a blocks miR-122 mimic treatment-induced decrease of Pla2g2a in blood cells after ischemic stroke. In summary, our data suggest miR-122 mimic can treat IS and ICH. Therefore, the miR-122 mimic treatment for IS and ICH could likely be performed without brain imaging (e.g. in the ambulance, and/or emergency room) since it is broadly efficacious for both IS and ICH.


2018 ◽  
Vol 50 (1) ◽  
pp. 261-276 ◽  
Author(s):  
Xiaobing Liu ◽  
Xing Luo ◽  
Yuqi Wu ◽  
Ding Xia ◽  
Wei Chen ◽  
...  

Background/Aims: Treatment options for metastatic castrate-resistant prostate cancer (mCRPC) are limited and typically centered on paclitaxel-based chemotherapy. In this study, we aimed to evaluate whether miR-34a attenuates chemoresistance to paclitaxel by regulating target genes associated with drug resistance. Methods: We used data from The Cancer Genome Atlas to compare miR-34a expression levels in prostate cancer (PC) tissues with normal prostate tissues. The effects of miR-34a inhibition and overexpression on PC proliferation were evaluated in vitro via Cell Counting Kit-8 (CCK-8) proliferation, colony formation, apoptosis, and cell-cycle assays. A luciferase reporter assay was employed to identify the interactions between miR-34a and specific target genes. To determine the effects of up-regulation of miR-34a on tumor growth and chemo-resistance in vivo, we injected PC cells overexpressing miR-34a into nude mice subcutaneously and evaluated the rate of tumor growth during paclitaxel treatment. We examined changes in the expression levels of miR-34a target genes JAG1 and Notch1 and their downstream genes via miR-34a transfection by quantitative reverse transcription PCR (qRT-PCR) and western blot assay. Results: miR-34a served as an independent predictor of reduced patient survival. MiR-34a was down-regulated in PC-3PR cells compared with PC-3 cells. The CCK-8 assay showed that miR-34a overexpression resulted in increased sensitivity to paclitaxel while miR-34a down-regulation resulted in chemoresistance to paclitaxel in vitro. A study of gain and loss in a series of functional assays revealed that PC cells expressing miR-34a were chemosensitive. Furthermore, the overexpression of miR-34a increased the sensitivity of PC-3PR cells to chemotherapy in vivo. The luciferase reporter assay confirmed that JAG1 and Notch1 were directly targeted by miR-34a. Interestingly, western blot analysis and qRT-PCR confirmed that miR-34a inhibited the Notch1 signaling pathway. We found that miR-34a increased the chemosensitivity of PC-3PR cells by directly repressing the TCF1/ LEF1 axis. Conclusion: Our results showed that miR-34a is involved in the development of chemosensitivity to paclitaxel. By regulating the JAG1/Notch1 axis, miR-34a or its target genes JAG1 or Notch1 might serve as potential predictive biomarkers of response to paclitaxel-based chemotherapy and/or therapeutic targets that will help to overcome chemoresistance at the mCRPC stage.


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Hong Liang ◽  
Qiuyan Zhao ◽  
Zhonglin Zhu ◽  
Chao Zhang ◽  
Hui Zhang

Abstract Background Long noncoding RNAs (lncRNAs) have been elucidated to participate in the development and progression of various cancers. In this study, we aimed to explore the underlying functions and mechanisms of LINC00958 in colorectal cancer. Methods LINC00958 expression in colorectal cancer tissues was examined by qRT-PCR. The correlations between LINC00958 expression and clinical characteristics and prognosis were evaluated. The biological functions of LINC00958 were detected by CCK-8, MTT, colony formation and flow cytometric analyses. RNA pulldown, RIP and luciferase reporter assays were used to confirm the regulatory effects of LINC00958 on miR-422a. Rescue experiments were performed to detect the effects of miR-422a on the roles of LINC00958. Results LINC00958 was upregulated in colorectal cancer tissues and cell lines. High LINC00958 levels were positively associated with T stage and predicted poor prognosis. Cell experiments showed that LINC00958 promoted cell proliferation and suppressed apoptosis and sensitivity to radiotherapy in vitro and promoted tumor growth in vivo. Bioinformatics analysis predicted the binding site of miR-422a on LINC00958. Mechanistically, RNA pulldown, RIP and luciferase reporter assays demonstrated that LINC00958 specifically targeted miR-422a. In addition, we found that miR-422a suppressed MAPK1 expression by directly binding to the 3’-UTR of MAPK1, thereby inhibiting cell proliferation and enhancing cell apoptosis and radiosensitivity. Furthermore, miR-422a rescued the roles of LINC00958 in promoting MAPK1 expression and cell proliferation and decreasing cell apoptosis and radiosensitivity. Conclusions LINC00958 promoted MAPK1 expression and cell proliferation and suppressed cell apoptosis and radiosensitivity by targeting miR-422a, which suggests that it is a potential biomarker for the prognosis and treatment of colorectal cancer.


Cancers ◽  
2021 ◽  
Vol 13 (22) ◽  
pp. 5710
Author(s):  
Xiaohui Zhang ◽  
Tingyu Li ◽  
Ya-Nan Han ◽  
Minghui Ge ◽  
Pei Wang ◽  
...  

Metastasis contributes to the poor prognosis of colorectal cancer, the causative factor of which is not fully understood. Previously, we found that miR-125b (Accession number: MIMAT0000423) contributed to cetuximab resistance in colorectal cancer (CRC). In this study, we identified a novel mechanism by which miR-125b enhances metastasis by targeting cystic fibrosis transmembrane conductance regulator (CFTR) and the tight junction-associated adaptor cingulin (CGN) in CRC. We found that miR-125b expression was upregulated in primary CRC tumors and metastatic sites compared with adjacent normal tissues. Overexpression of miR-125b in CRC cells enhanced migration capacity, while knockdown of miR-125b decreased migration and invasion. RNA-sequencing (RNA-seq) and dual-luciferase reporter assays identified CFTR and CGN as the target genes of miR-125b, and the inhibitory impact of CFTR and CGN on metastasis was further verified both in vitro and in vivo. Moreover, we found that miR-125b facilitated the epithelial-mesenchymal transition (EMT) process and the expression and secretion of urokinase plasminogen activator (uPA) by targeting CFTR and enhanced the Ras Homolog Family Member A (RhoA)/Rho Kinase (ROCK) pathway activity by targeting CGN. Together, these findings suggest miR-125b as a key functional molecule in CRC and a promising biomarker for the diagnosis and treatment of CRC.


Author(s):  
Cong Cao ◽  
Jun Li ◽  
Guangzhi Li ◽  
Gaoyu Hu ◽  
Zhihua Deng ◽  
...  

Long non-coding RNAs (lncRNAs) have a considerable regulatory influence on multiple biological processes. Nevertheless, the role of TMEM220-AS1 in hepatocellular carcinoma (HCC) remains unclear. We used The Cancer Genome Atlas (TCGA) database to analyze the differentially expressed lncRNAs. qRT-PCR was used to verify the results for a large population. The in vitro effects of TMEM220-AS1 on HCC cells were determined using Cell Counting Kit-8 (CCK-8), 5-ethynyl-2’-deoxyuridine (EdU), flow cytometry, and Transwell assays in HCC cells. We used qRT-PCR and western blotting to identify the epithelial-mesenchymal transition (EMT). Moreover, we performed bioinformatics analysis, western blotting, dual luciferase reporter gene assay, RNA pull-down, and RNA binding protein immunoprecipitation (RIP) to investigate the underlying molecular mechanisms of TMEM220-AS1 function. Finally, the function of TMEM220-AS1 was verified in vivo. The results showed that TMEM220-AS1 was expressed at considerably low levels in HCC. It was demonstrated that malignant phenotypes and EMT of HCC cells were promoted by the knock down of TMEM220-AS1 both in vivo and in vitro. TMEM220-AS1, which was detected primarily in the cytoplasm, functioned as an miRNA sponge to bind miR-484 and promote the level of membrane-associated guanylate kinase, WW, and PDZ domain containing 1 (MAGI1), thereby curbing the malignant phenotypes of HCC cells. In conclusion, low levels of TMEM220-AS1 promote proliferation and metastasis through the miR-484/MAGI1 axis in HCC.


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