scholarly journals Positive Reciprocal Feedback of lncRNA ZEB1-AS1 and HIF-1α Contributes to Hypoxia-Promoted Tumorigenesis and Metastasis of Pancreatic Cancer

2021 ◽  
Vol 11 ◽  
Author(s):  
Yan Jin ◽  
Zhengming Zhang ◽  
Qiao Yu ◽  
Zhu Zeng ◽  
Hong Song ◽  
...  

BackgroundMany studies have reported the roles of the extracellular hypoxia microenvironment in the tumorigenesis and metastasis of multiple cancers. However, long noncoding RNAs (lncRNAs) that induce cancer oncogenicity and metastasis of pancreatic cancer (PC) under hypoxia conditions remain unclear.MethodsIn PC cells, the expression levels of lncRNAs in different conditions (normoxia or hypoxia) were compared through RNA sequencing (RNA-seq). The effects of the zinc finger E-box-binding homeobox 1 (ZEB1-AS1) antisense lncRNA on PC cells cultured in normoxia/hypoxia medium were measured through gain and loss-of-function experiments. Fluorescence in situ hybridization and luciferase reporter assays in addition to in vivo studies were utilized to explore the adaptive mechanisms of ZEB1-AS1 in the hypoxia-promoted proliferation, migration, and invasion ability of PC cells. Moreover, the level of ZEB1-AS1 and its associated targets or pathways were investigated in both PC and pancreatic normal tissues.ResultsRNA-seq revealed that ZEB1-AS1 was significantly upregulated in PC cells under hypoxia conditions. The ZEB1-AS1 expression level was closely associated with poor prognosis of PC patients. Knockdown of ZEB1-AS1 suppressed the proliferation, migration, and invasion of PC cells in vitro as well as PC xenograft tumor growth in vivo. In PC cells, RNAi-mediated reduction of ZEB1-AS1 inhibited zinc finger E-box-binding homeobox 1 (ZEB1), while ZEB1-AS1 overexpression rescued ZEB1 expression, indicating that ZEB1-AS1 promotes ZEB1 expression. Moreover, hypoxia-inducible factor-1α (HIF-1α)induced the expression of ZEB1-AS1 by binding to the ZEB1-AS1 promoter, which contains a putative hypoxia response element (HRE). Mechanistically, ZEB1-AS1 scaffolded the interaction among HIF-1α, ZEB1, and histone deacetylase 1 (HDAC1), leading to deacetylation-mediated stabilization of HIF-1α. We further revealed that ZEB1 induced the deacetylase capacity of HDAC1 to suppress the acetylation or degradation of HIF-1α, improving HIF-1α assembly. Thus, hypoxia-induced ZEB1-AS1 facilitated ZEB1 transcription and the stability of HIF-1α, which promoted the metastasis of PC cells. Clinically, dysregulated ZEB1 and HIF-1α expression was significantly correlated with histological grade, lymphatic metastasis, and distant metastasis in PC patients.ConclusionsOur results emphasized that the positive reciprocal loop of HIF-1α/ZEB1-AS1/ZEB1/HDAC1 contributes to hypoxia-promoted oncogenicity and PC metastasis, indicating that it might be a novel therapeutic target for PC.

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Xinyi Qian ◽  
Juze Yang ◽  
Qiongzi Qiu ◽  
Xufan Li ◽  
Chengxi Jiang ◽  
...  

Abstract Background Long non-coding RNAs (lncRNAs) are important epigenetic regulators, which play critical roles in diverse physiological and pathological processes. However, the regulatory mechanism of lncRNAs in lung carcinogenesis remains elusive. Here, we characterized a novel oncogenic lncRNA, designated as Lung Cancer Associated Transcript 3 (LCAT3). Methods We predicted and validated LCAT3 by analyzing RNA-sequencing (RNA-seq) data of lung cancer tissues from TCGA. Methylated RNA immunoprecipitation was performed to assess m6A modification on LCAT3. The LCAT3-FUBP1-MYC axis was assessed by dual-luciferase reporter, RNA immunoprecipitation and Chromatin immunoprecipitation assays. Signaling pathways altered by LCAT3 knockdown were identified using RNA-seq. Furthermore, the mechanism of LCAT3 was investigated using loss-of-function and gain-of-function assays in vivo and in vitro. Results LCAT3 was found to be up-regulated in lung adenocarcinomas (LUAD), and its over-expression was associated with the poor prognosis of LUAD patients. LCAT3 upregulation is attributable to N6-methyladenosine (m6A) modification mediated by methyltransferase like 3 (METTL3), leading to LCAT3 stabilization. Biologically, loss-of-function assays revealed that LCAT3 knockdown significantly suppressed lung cancer cell proliferation, migration and invasion in vitro, and inhibited tumor growth and metastasis in vivo. LCAT3 knockdown induced cell cycle arrest at the G1 phase. Mechanistically, LCAT3 recruited Far Upstream Element Binding Protein 1 (FUBP1) to the MYC far-upstream element (FUSE) sequence, thereby activating MYC transcription to promote proliferation, survival, invasion and metastasis of lung cancer cells. Conclusions Taken together, we identified and characterized LCAT3 as a novel oncogenic lncRNA in the lung, and validated the LCAT3-FUBP1-MYC axis as a potential therapeutic target for LUAD.


Author(s):  
Yihong Huang ◽  
Shuo Zheng ◽  
Ying Lin ◽  
Liming Ke

Triple negative breast cancer (TNBC) is an aggressive histological subtype of breast cancer. It has been reported that that circRNA circ-ERBB2 (circBase ID: hsa_circ_0007766) is mainly distributed in the cytoplasm of TNBC cells and promotes the proliferation and invasion of TNBC cells. This study aimed to explore the molecular mechanism of circ-ERBB2 regulating the progression of TNBC. Expression of circ-ERBB2 was detected by quantitative real-time polymerase chain reaction (qRT-PCR). Loss-of-function experiments were performed to investigate the function of circ-ERBB2 in TNBC cells in vitro and in vivo . The regulatory mechanism of circ-ERBB2 was surveyed by bioinformatics analysis, dual-luciferase reporter and RNA immunoprecipitation (RIP) or RNA pull-down assays. We observed that Circ-ERBB2 was overexpressed in TNBC, and TNBC patients with high circ-ERBB2 expression had a poor prognosis. Functionally, circ-ERBB2 knockdown constrained TNBC growth in vivo and reduced Warburg effect, accelerated apoptosis, repressed proliferation, migration, and invasion of TNBC cell in vitro . Mechanically, circ-ERBB2 sponged miR-136-5p to elevate pyruvate dehydrogenase kinase 4 (PDK4) expression. In conclusion, circ-ERBB2 facilitated Warburg effect and malignancy of TNBC cells by the miR-136-5p/PDK4 pathway, at least in part. This study supported circ-ERBB2 as a prognostic indicator for TNBC.


2021 ◽  
Vol 11 ◽  
Author(s):  
Xuchen Dong ◽  
Peng Zhang ◽  
Liang Liu ◽  
Haoran Li ◽  
Shan Cheng ◽  
...  

Glioma is the most common primary intracranial malignant tumour in adults. It has a high incidence and poses a serious threat to human health. Circular RNA is a hotspot of cancer research. In this study, we aimed to explore the role of circ_0001367 in gliomagenesis and the underlying mechanism. First, qRT-PCR was conducted, which showed that circ_0001367 level was downregulated in glioma tissues and cells. Next, gain-of-function and loss-of-function assays were performed, which indicated that circ_0001367 inhibited the proliferation, migration and invasion of glioma cells. Subsequent bioinformatics analysis, dual-luciferase reporter assays, RNA immunoprecipitation assays and cell function assays demonstrated that circ_0001367 inhibited the proliferation, migration and invasion of glioma cells by absorbing miR-545-3p and thereby regulating the expression of leucine zipper protein (LUZP1). Finally, an in vivo experiment was conducted, which demonstrated that circ_0001367 inhibited glioma growth in vivo by modulating miR-545-3p and LUZP1. Taken together, the results of this study demonstrate that the circ_0001367/miR-545-3p/LUZP1 axis may be a novel target for glioma therapy.


2021 ◽  
Author(s):  
Yuhua He ◽  
Shuifang Xu ◽  
Yi Qi ◽  
Jinfang Tian ◽  
Fengying Xu

Abstract BackgroundSmall nucleolar RNA host gene 25 (SNHG25), a long-noncoding RNA, has been well studied in epithelial ovarian cancer. Yet, the specific functions of SNHG25 in endometrial cancer (EC) have not been researched. In this study, we proposed to expose the clinic significance of SNHG25 in EC, and then unravel the regulatory activity of SNHG25 on the tumor-associated phenotype of EC. More interestingly, the possible molecular events occurred when SNHG25 executives its function in EC were explored thoroughly. MethodsWe measured genes expression applying quantitative real-time polymerase chain reaction. The detailed functions of SNHG25 in EC were examined employing loss-of-function experiments. What’s more, we unveiled the regulatory mechanisms among SNHG25, microRNA-497-5p and fatty acid synthase (FASN) with the application of luciferase reporter assay and RNA Immunoprecipitation. ResultsWe verified a high level of SNHG25 in EC through TCGA dataset and our own cohort. Patients with a high SNHG25 level featured shorter overall survival in contrast to patients with a low SNHG25 level. SNHG25 deficient caused tumor-repressing actions in EC cells by decreasing cell proliferation, migration and invasion and promoting cell apoptosis. Furthermore, we certified the function of SNHG25 depletion in impairing tumor growth in vivo. With respect to the mechanisms, SNHG25 sequestered miR-497-5p as a competing endogenous RNA in EC and consequently positively regulated FASN expression. Striking, the decrease of miR-497-5p or increase of FASN could neutralize the modulatory actions of SNHG25 knockdown in EC cells. ConclusionsDepleted SNHG25 hampered the oncogenicity of EC by targeting miR-497-5p/FASN axis. The newly certified SNHG25/miR-497-5p/FASN pathway may potentially have usefulness as a promising target for molecular targeted management.


Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 40-40
Author(s):  
Chandraditya Chakraborty ◽  
Eugenio Morelli ◽  
Srikanth Talluri ◽  
Sanika Derebail ◽  
Yan Xu ◽  
...  

Multiple myeloma (MM) is a biologically heterogeneous plasma cell malignancy, however, the mechanisms underlying this complexity are incompletely understood. By deep (70x) whole-genome sequencing (WGS) of 312 primary MM patients, we observed mutations in about 62% of patients in the 5' untranslated region and intron 1 of the 12q24.3 region which cytogenetically marks the BCL7A gene. Integration of WGS with RNA-seq data suggested a widespread loss of BCL7A expression in MM cells as compared to normal plasma cells (PC). To understand the effect of noncoding mutations in BCL7A promoter we performed in-vitro luciferase reporter assay in MM cell lines (H929, MM1S and KK1) devoid of BCL7A mutation in 5'UTR and found that the normalized luciferase reporter activity indicated that the mutation in the promoter significantly reduced BCL7A promoter activity. Next, we recapitulated the loss of BCL7A observed in MM patients, in a panel of MM cell lines using shRNA based genetic interference and observed the appearance of a more proliferative phenotype. The effects of BCL7A loss in MM cells were further confirmed using CRISPR-Cas9 system. BCL7A-KO (knock-out) cells had higher proliferative rate compared to wild type (WT) cells and lentiviral add back of BCL7A plasmid reversed this effect. This phenomenon was validated in a in vivo model, where we found that mice bearing BCL7A KO MM cells developed tumors faster than mice injected with control or add-back cells, suggesting that BCL7A loss increases tumorigenesis in vivo. On the other hand, ectopic expression of BCL7A significantly reduced cell viability and colony formation over time, inducing apoptotic cell death and impacting genes involved in chromatin and chromosome organization, DNA repair and cell cycle. Interestingly, BCL7A is an important member of the m-SWI/SNF chromatin remodeling complex. Using comparative mass spectrometry analysis, we observed that BCL7A expression is essential for the formation of a functional canonical m-SWI/SNF complex in MM cells, controlling the incorporation of active sub-units into the complex. These data suggest that loss-of-function mutations in the BCL7A region may disrupt the formation of SWI/SNF complex activating a transcriptional program that leads to MM cell growth and viability. We therefore evaluated the transcriptomic changes in MM cells upon BCL7A perturbation in a panel of MM cell lines by whole genome RNA-seq. Integrated analysis of modulated genes identified a set of 23 genes significantly upregulated in the presence of BCL7A depletion and downregulated in presence of BCL7A ectopic expression. To investigate whether these genes are involved in the phenotypic and functional effects observed in MM after BCL7A depletion, we performed LOF (loss-of-function) studies (si-RNA screen) using these genes in scrambled and BCL7A KD (knock-down) MM cells. Among others, we observed that MM cells are highly sensitive to the inhibition of RPS3A (V-Fos transformation effector protein) only in the context of BCL7A loss. Our RNA-seq data revealed that RPS3A is highly expressed in primary MM cells, and its expression significantly correlates with low expression of BCL7A in MM patients. Importantly, we observed that RPS3A binds to the core m-SWI/SNF complex proteins; SMARCC2 and SMARCB1 in the absence of BCL7A. RPS3A gene encodes a ribosomal protein that is a component of the 40S subunit and its overexpression transforms NIH3T3 mouse fibroblasts and induces tumor formation in nude mice and also used as an expression marker in squamous cell carcinoma. In conclusion, we here report biological consequences of a frequent non-coding mutation of BCL7A in MM and loss-of-function mutations in the BCL7A region may disrupt the formation of SWI/SNF complex activating a transcriptional process that leads to MM cell growth and viability. Altogether this study shed lights on a new pathogenic mechanism that may drive MM growth with potential translational implication, that may be applicable to other hematological diseases. Disclosures Anderson: Oncopep and C4 Therapeutics.: Other: Scientific Founder of Oncopep and C4 Therapeutics.; Bristol Myers Squibb: Membership on an entity's Board of Directors or advisory committees; Sanofi-Aventis: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees; Gilead: Membership on an entity's Board of Directors or advisory committees; Millenium-Takeda: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees. Fulciniti:NIH: Research Funding. Munshi:BMS: Consultancy; OncoPep: Consultancy, Current equity holder in private company, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties; C4: Current equity holder in private company; Janssen: Consultancy; Adaptive: Consultancy; Legend: Consultancy; Amgen: Consultancy; AbbVie: Consultancy; Karyopharm: Consultancy; Takeda: Consultancy.


2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Yu-Shui Ma ◽  
Xiao-Li Yang ◽  
Yu-Shan Liu ◽  
Hua Ding ◽  
Jian-Jun Wu ◽  
...  

Abstract Background Cancer stem cells (CSCs) are key regulators in the processes of tumor initiation, progression, and recurrence. The mechanism that maintains their stemness remains enigmatic, although the role of several long noncoding RNAs (lncRNAs) has been highlighted in the pancreatic cancer stem cells (PCSCs). In this study, we first established that PCSCs overexpressing lncRNA NORAD, and then investigated the effects of NORAD on the maintenance of PCSC stemness. Methods Expression of lncRNA NORAD, miR-202-5p and ANP32E in PC tissues and cell lines was quantified after RNA isolation. Dual-luciferase reporter assay, RNA pull-down and RIP assays were performed to verify the interactions among NORAD, miR-202-5p and ANP32E. We then carried out gain- and loss-of function of miR-202-5p, ANP32E and NORAD in PANC-1 cell line, followed by measurement of the aldehyde dehydrogenase activity, cell viability, apoptosis, cell cycle distribution, colony formation, self-renewal ability and tumorigenicity of PC cells. Results LncRNA NORAD and ANP32E were upregulated in PC tissues and cells, whereas the miR-202-5p level was down-regulated. LncRNA NORAD competitively bound to miR-202-5p, and promoted the expression of the miR-202-5p target gene ANP32E thereby promoting PC cell viability, proliferation, and self-renewal ability in vitro, as well as facilitating tumorigenesis of PCSCs in vivo. Conclusion Overall, lncRNA NORAD upregulates ANP32E expression by competitively binding to miR-202-5, which accelerates the proliferation and self-renewal of PCSCs.


2017 ◽  
Vol 44 (5) ◽  
pp. 1867-1881 ◽  
Author(s):  
Bin Zhou ◽  
Chuandong Sun ◽  
Xiao Hu ◽  
Hanxiang Zhan ◽  
Hao Zou ◽  
...  

Background/Aims: Doublecortin-like kinase 1 (DCLK1) is emerging as a tumor-specific stem cell marker in pancreatic cancer (PC). MicroRNA-195 (miR-195) plays an important role in many types of tumors. However, the roles of DCLK1 in cancer and miRNAs that directly regulate DCLK1 have not been elucidated. The goal of this study is to assess the effects of miR-195 on inhibiting DCLK1 and to clarify the regulating mechanism of miR-195-DCLK1 in PC cells. Methods: The expression of DCLK1 protein and miR-195 in PC tissues and adjacent healthy pancreatic tissues was detected by Western blot and quantitative reverse transcription polymerase chain reaction (qRT-PCR), respectively and the correlation between overall survival of PC patients and expression of DCLK1 was measured by Kaplan-Meier analysis. Bioinformatics tools were used to identify the target gene of miR-195. Effects of miR-195 and DCLK1 on proliferation and cell cycle of PC cells were analyzed by MTT, colony formation assays and flow cytometry. Transwell and wound-healing experiments were employed to examine the cellular migration and invasion. A xenograft mouse model was also used to test the effects of miR-195 on tumor growth and metastasis in vivo. Results: The expression level of DCLK1 and miR-195 shows an inverse correlation in PC tissues and cell lines. A higher DCLK1 level is associated with higher TNM (tumor, node, and metastasis) stage, higher rate of lymph node metastasis, and poor survival. Luciferase reporter assay shows that miR-195 directly targets DCLK1. Overexpression of miR-195 inhibits proliferation, migration and invasion of PC cells, whereas downregulation of miR-195 has an opposite role. These actions were similar to the effects of knockdown and overexpression of DCLK1, respectively. Conclusions: These data suggest that miR-195 has tumor suppressor roles in PC by targeting DCLK1. MiR-195-DCLK1 pathway may provide insight into PC progression and represent a novel, promising diagnostic and therapeutic target for PC.


2021 ◽  
Vol 30 ◽  
pp. 096368972097539
Author(s):  
Jian Li ◽  
Yongjing Yang ◽  
Dequan Xu ◽  
Ling Cao

Gastric cancer (GC) is a big threat to human life and health. Circular RNAs (circRNAs), a subclass of noncoding RNAs, were reported to play a critical role in GC progression. Here, we investigated the role of a novel circRNA named hsa_circ_0023409 in GC and its mechanism. Hsa_circ_0023409 expression in GC and adjacent tissues was examined by quantitative real-time polymerase chain reaction and in situ hybridization. The functions of hsa_circ_0023409 in GC cells were assessed both in vitro and in vivo. Immunofluorescence staining was performed for the localization of hsa_circ_0023409 and miR-542-3p in cells. The interaction between hsa_circ_0023409 and miR-542-3p, and miR-542-3p and insulin receptor substrate 4 (IRS4) was detected by dual-luciferase reporter assay. The effect of hsa_circ_0023409, miR-542-3p, and IRS4 on IRS4/phosphatidylinositol 3-kinase (PI3K)/AKT pathway was detected by western blot. The results showed that hsa_circ_0023409 was mainly located in cytoplasm and highly expressed in GC tissues and cells. Moreover, hsa_circ_0023409 showed positive correlation with tumor size, histological grade, and tumor–node–metastasis staging of GC patients. Functional studies showed that hsa_circ_0023409 promoted cell viability, proliferation, migration, and invasion and suppressed apoptosis in GC. Mechanism studies demonstrated that hsa_circ_0023409 upregulated IRS4 via sponging miR-542-3p in GC cells. Furthermore, IRS4 overexpression activated the PI3K/AKT pathway and reversed the inhibitory effect of hsa_circ_0023409 knockdown on the PI3K/AKT pathway. Taken together, we prove that hsa_circ_0023409 activates IRS4/PI3K/AKT pathway by acting as a sponge for miR-542-3p, thus promoting GC progression, indicating that hsa_circ_0023409 may serve as a potential target for treatment of GC and prognosis of GC patients.


2021 ◽  
Vol 2021 ◽  
pp. 1-21
Author(s):  
Shibo Zhu ◽  
Xiangliang Tang ◽  
Xiaofeng Gao ◽  
Jingqi Zhang ◽  
Yanhong Cui ◽  
...  

Background. Increased levels of circRNAs have been identified in a variety of cancers. However, the specific functions and mechanisms of circRNAs in neuroblastoma (NB) have not been fully explored. Methods. The levels of hsa_circ_0045997, hsa_circ_0080307, hsa_circ_0013401, hsa_circ_0077578, and microRNA-195 were confirmed by RT-qPCR in NB. Gain- and loss-of-function assays and rescue experiments were conducted to determine the influence of hsa_circ_0013401, miR-195, and P21-activated kinase 2 (PAK2) on the proliferation, apoptosis, autophagy, migration, and invasion of NB cells. Regulatory gene targets were validated by the luciferase assay. A xenograft mouse model was used to determine the in vivo effects of hsa_circ_0013401. Results. hsa_circ_0013401 was highly expressed, miR-195 was lowly expressed, and there was a negative correlation between hsa_circ_0013401 and miR-195 in NB. The inhibitory effects of hsa_circ_0013401 knockdown suppressed the proliferation, migration, and invasion and induced the apoptosis and autophagy of NB cells by targeting miR-195 to downregulate PAK2 expression. Luciferase reporter assays showed that miR-195 was a direct target of hsa_circ_0013401, and PAK2 was the downstream target gene of miR-195. In vivo studies showed that hsa_circ_0013401 promotes tumor formation. Conclusions. hsa_circ_0013401 induced NB progression through miR-195 to enhance PAK2. Therefore, we might highlight a novel regulatory axis (hsa_circ_0013401/miR-195/PAK2) in NB.


2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Yifan Li ◽  
Jing Xun ◽  
Botao Wang ◽  
Yuan Ma ◽  
Lanqiu Zhang ◽  
...  

Abstract Background Colorectal cancer is one of the most common malignancy in the world. It has been reported that cancer stem cells (CSCs) serve as the primary drivers of tumorigenesis and tumor progression. There is an urgent need to explore novel molecules that regulate CSCs or their signatures. Increasing evidence has shown that miRNAs are involved in tumorigenesis and progression. Here, we aim to explore the regulatory effect and mechanism of miR-3065-3p on the stemness of colorectal cancer. Methods The expression of miR-3065-3p in colorectal cancer and the association of miR-3065-3p expression with prognosis of patients with colorectal cancer were analyzed using TCGA dataset or clinical cases. Gain or loss of function in different models, including colorectal cancer cell lines and orthotopic xenograft or liver metastatic mouse model, were used to investigate the effects of miR-3065-3p on colorectal cancer stemness and metastasis in vitro and in vivo. Cancer stemness was analyzed by detecting the ability of migration and invasion, NANOG, OCT4, and SOX2 expression, ALDH activity and sphere formation. In addition, the interaction of miR-3065-3p and cytokine receptor-like factor 1 (CRLF1) was analyzed theoretically and identified by the luciferase reporter assay. Moreover, the correlation between CRLF1 expression and miR-3065-3p was analyzed in colorectal cancer tissues. Finally, the effect of CRLF1 on the stemness and metastasis of colorectal cancer in vitro and in vivo was assessed. Results In this report, we found that miR-3065-3p was overexpressed in colorectal cancer and that its high expression was associated with poor prognosis of patients with colorectal cancer. miR-3065-3p promotes the stemness and metastasis of colorectal cancer. Furthermore, CRLF1 was the downstream target of miR-3065-3p and inhibited the stemness of colorectal cancer. In addition, CRLF1 expression was negatively correlated with miR-3065-3p in colorectal cancer tissues. And, CRLF1 mediated the effects of miR-3065-3p on promoting stemness of colorectal cancer cells. Conclusion Our data suggest that miR-3065-3p promoted the stemness and metastasis of colorectal cancer by targeting CRLF1. miR-3065-3p might serve as a promising prognostic marker as well as a therapeutic target for colorectal cancer.


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