scholarly journals CDK13 upregulation-induced formation of the positive feedback loop among circCDK13, miR-212-5p/miR-449a and E2F5 contributes to prostate carcinogenesis

Author(s):  
Jin-Chun Qi ◽  
Zhan Yang ◽  
Tao Lin ◽  
Long Ma ◽  
Ya-Xuan Wang ◽  
...  

Abstract Background Both E2F transcription factor and cyclin-dependent kinases (CDKs), which increase or decrease E2F activity by phosphorylating E2F or its partner, are involved in the control of cell proliferation, and some circRNAs and miRNAs regulate the expression of E2F and CDKs. However, little is known about whether dysregulation among E2Fs, CDKs, circRNAs and miRNAs occurs in human PCa. Methods The expression levels of CDK13 in PCa tissues and different cell lines were determined by quantitative real-time PCR and Western blot analysis. In vitro and in vivo assays were preformed to explore the biological effects of CDK13 in PCa cells. Co-immunoprecipitation anlysis coupled with mass spectrometry was used to identify E2F5 interaction with CDK13. A CRISPR-Cas9 complex was used to activate endogenous CDK13 and circCDK13 expression. Furthermore, the mechanism of circCDK13 was investigated by using loss-of-function and gain-of-function assays in vitro and in vivo. Results Here we show that CDK13 is significantly upregulated in human PCa tissues. CDK13 depletion and overexpression in PCa cells decrease and increase, respectively, cell proliferation, and the pro-proliferation effect of CDK13 is strengthened by its interaction with E2F5. Mechanistically, transcriptional activation of endogenous CDK13, but not the forced expression of CDK13 by its expression vector, remarkably promotes E2F5 protein expression by facilitating circCDK13 formation. Further, the upregulation of E2F5 enhances CDK13 transcription and promotes circCDK13 biogenesis, which in turn sponges miR-212-5p/449a and thus relieves their repression of the E2F5 expression, subsequently leading to the upregulation of E2F5 expression and PCa cell proliferation. Conclusions These findings suggest that CDK13 upregulation-induced formation of the positive feedback loop among circCDK13, miR-212-5p/miR-449a and E2F5 is responsible for PCa development. Targeting this newly identified regulatory axis may provide therapeutic benefit against PCa progression and drug resistance.

2021 ◽  
Vol 11 ◽  
Author(s):  
Tao Guo ◽  
Defeng Liu ◽  
Shihao Peng ◽  
Meng Wang ◽  
Yangyang Li

BackgroundColorectal cancer (CRC) is a common malignant tumor with high metastatic and recurrent rates. This study probes the effect and mechanism of long non-coding RNA MIR31HG on the progression of CRC cells.Materials and MethodsQuantitative real-time PCR (qRT-PCR) was used to analyze the expression of MIR31HG and miR-361-3p in CRC tissues and normal tissues. Gain- or loss-of-function assays were conducted to examine the roles of MIR31HG, miR-361-3p and YY1 transcription factor (YY1) in the CRC progression. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, and colony formation experiment were conducted to test CRC cell proliferation. CRC cell invasion was determined by Transwell assay. The glucose detection kit and lactic acid detection kit were utilized to monitor the levels of glucose and lactate in CRC cells. The glycolysis level in CRC cells was examined by the glycolytic stress experiment. Western blot was performed to compare the expression of glycolysis-related proteins (PKM2, GLUT1 and HK2) and angiogenesis-related proteins (including VEGFA, ANGPT1, HIF1A and TIMP1) in HUVECs. The binding relationships between MIR31HG and miR-361-3p, miR-361-3p and YY1 were evaluated by the dual-luciferase reporter assay and RNA immunoprecipitation (RIP).ResultsMIR31HG was up-regulated in CRC tissues and was associated with poorer prognosis of CRC patients. The in-vitro and in-vivo experiments confirmed that overexpressing MIR31HG heightened the proliferation, growth, invasion, glycolysis and lung metastasis of CRC cells as well as the angiogenesis of HUVECs. In addition, MIR3HG overexpression promoted YY1 mRNA and protein level, and forced overexpression of YY1 enhanced MIR31HG level. Overexpressing YY1 reversed the tumor-suppressive effect mediated by MIR31HG knockdown. miR-361-3p, which was inhibited by MIR31HG overexpression, repressed the malignant behaviors of CRC cells. miR-361-3p-mediated anti-tumor effects were mostly reversed by upregulating MIR31HG. Further mechanism studies illustrated that miR-361-3p targeted and negatively regulated the expression of YY1.ConclusionThis study reveals that MIR31HG functions as an oncogenic gene in CRC via forming a positive feedback loop of MIR31HG-miR-361-3p-YY1.


2021 ◽  
Vol 11 ◽  
Author(s):  
Fan Yang ◽  
Chong Yuan ◽  
Dan Wu ◽  
Jing Zhang ◽  
Xingchun Zhou

Castration-resistant prostate cancer (CRPC) is the lethal form of prostate cancer (PCa), and the underlying molecular mechanism has not been fully elucidated. Inositol requiring enzyme 1 alpha (IRE1α), a key regulator of unfolded protein response (UPR), is intimately associated with PCa progression. However, whether IRE1α is implicated in CRPC development remains unknown. Here, we showed that IRE1α expression was significantly increased in CRPC tissues and high-grade PCa tissues. Overexpression of IRE1α promoted PCa cell proliferation under the androgen deficiency condition in vitro and in vivo. Mechanistically, increased IRE1α expression induced IL-6 secretion via the IRE1α/XBP-1s signal pathway. IRE1α-induced IL-6 activated androgen receptor (AR), and the activation of AR by IL-6, in turn, promoted IRE1α expression. IRE1α formed a positive feedback loop with IL-6 and AR to promote prostate cancer cell proliferation under the androgen-deficient condition. In clinical PCa samples, high IRE1α expression correlated with elevated IL-6 and increased PSA expression. Our findings demonstrated a novel mechanism of CRPC progression and suggest targeting IRE1α may be a potential target for the prevention and treatment of CRPC.


Author(s):  
Yiwen Xia ◽  
Jialun Lv ◽  
Tianlu Jiang ◽  
Bowen Li ◽  
Ying Li ◽  
...  

Abstract Background Circular RNAs (circRNAs) have emerged as a new subclass of regulatory RNAs that play critical roles in various cancers. Cancer stem cells (CSCs), a small subset of cancer cells, are believed to possess the capacities to initiate tumorigenesis and promote progression. Although accumulating evidence has suggested that cells with CSC-like properties are crucial for the malignancy of gastric cancer (GC), it remains unclear whether circRNAs are related to the acquisition of CSC-like properties in GC. Methods CircFAM73A expression was analyzed by GEO datasets and verified in GC samples. The roles of circFAM73A in GC cell proliferation, migration, cisplatin resistance, and CSC-like properties were determined by a series of functional experiments both in vitro and in vivo. RNA pulldown was used to explore the miRNAs and proteins binding to circFAM73A. Bioinformatic analysis and experimental verification confirmed the downstream targets of circFAM73A. The regulation of circFAM73A by HMGA2 was verified by ChIP and RIP assays. Results Elevated circFAM73A expression was confirmed in GC tissues, and higher circFAM73A predicted poor prognosis in GC patients. The upregulation of circFAM73A enhanced CSC-like properties in GC, thus facilitating cell proliferation, migration, and cisplatin resistance. Mechanistically, circFAM73A promoted GC malignancy by regulating miR-490-3p/HMGA2 in a positive feedback loop and recruiting HNRNPK to facilitate β-catenin stabilization. Moreover, HMGA2 further enhanced E2F1 and HNRNPL activity, which in turn promoted circFAM73A expression. Conclusions Our work demonstrates the crucial role of circFAM73A in the CSC-like properties of GC and uncovers a positive feedback loop in circFAM73A regulation that leads to the progression of gastric cancer, which may provide new insights into circRNA-based diagnostic and therapeutic strategies.


2014 ◽  
Vol 2014 ◽  
pp. 1-17 ◽  
Author(s):  
Ji Yeon Byun ◽  
Young-So Youn ◽  
Ye-Ji Lee ◽  
Youn-Hee Choi ◽  
So-Yeon Woo ◽  
...  

Recognition of apoptotic cells by macrophages is crucial for resolution of inflammation, immune tolerance, and tissue repair. Cyclooxygenase-2 (COX-2)/prostaglandin E2 (PGE2) and hepatocyte growth factor (HGF) play important roles in the tissue repair process. We investigated the characteristics of macrophage COX-2 and PGE2expression mediated by apoptotic cells and then determined how macrophages exposed to apoptotic cellsin vitroandin vivoorchestrate the interaction between COX-2/PGE2and HGF signaling pathways. Exposure of RAW 264.7 cells and primary peritoneal macrophages to apoptotic cells resulted in induction of COX-2 and PGE2. The COX-2 inhibitor NS-398 suppressed apoptotic cell-induced PGE2production. Both NS-398 and COX-2-siRNA, as well as the PGE2receptor EP2 antagonist, blocked HGF expression in response to apoptotic cells. In addition, the HGF receptor antagonist suppressed increases in COX-2 and PGE2induction. Thein vivorelevance of the interaction between the COX-2/PGE2and HGF pathways through a positive feedback loop was shown in cultured alveolar macrophages followingin vivoexposure of bleomycin-stimulated lungs to apoptotic cells. Our results demonstrate that upregulation of the COX-2/PGE2and HGF in macrophages following exposure to apoptotic cells represents a mechanism for mediating the anti-inflammatory and antifibrotic consequences of apoptotic cell recognition.


Author(s):  
Xu Liu ◽  
Kun Qiao ◽  
Kaiyuan Zhu ◽  
Xianglan Li ◽  
Chunbo Zhao ◽  
...  

In recent years, an increasing number of studies have reported that long noncoding RNAs (lncRNAs) play crucial roles in breast cancer (BC) progression and metastasis. Another study group of our research center reported that lncRNA HCG18 was one of the 30 upregulated lncRNAs in BC tissues compared with normal tissues in The Cancer Genome Atlas database. However, the exact biological roles of HCG18 in BC remain unclear. In this study, we demonstrated that HCG18 is significantly upregulated in BC tissues and cells and that BC patients with high HCG18 expression tend to have poor prognosis. In vitro assays indicated that HCG18 promotes BC cell proliferation and invasion and endows BC cells with cancer stemness properties. In vivo assays revealed that reducing HCG18 expression in the BC cell line MDA-MB-231 markedly decreased tumor growth and lung metastasis in xenograft mouse models. In terms of mechanism, we found that HCG18 positively regulated the expression of BC-related ubiquitin-conjugating enzyme E2O (UBE2O) by sponging miR-103a-3p, and our previous research verified that UBE2O could promote the malignant phenotypes of BC cells through the UBE2O/AMPKα2/mTORC1 axis. Furthermore, as a downstream target of the HCG18/miR-103a-3p/UBE2O/mTORC1 axis, hypoxia-inducible factor 1α transcriptionally promoted HCG18 expression and then formed a positive feedback loop in BC. Taken together, these results confirm that HCG18 plays an oncogenic role in BC and might serve as a prognostic biomarker and a potential therapeutic target for BC treatment.


Author(s):  
Bin Zhu ◽  
Jun-Jie Chen ◽  
Ying Feng ◽  
Jun-Ling Yang ◽  
Hua Huang ◽  
...  

Abstract Background Angiogenesis plays an important role in the occurrence, development and metastasis of hepatocellular carcinoma (HCC). According to previous studies, miR-378a participates in tumorigenesis and tumor metastasis, but its exact role in HCC angiogenesis remains poorly understood. Methods qRT-PCR was used to investigate the expression of miR-378a-3p in HCC tissues and cell lines. The effects of miR-378a-3p on HCC in vitro and in vivo were examined by Cell Counting Kit-8 (CCK-8), Transwell, tube formation and Matrigel plug assays, RNA sequencing, bioinformatics, luciferase reporter, immunofluorescence and chromatin immunoprecipitation (ChIP) assays were used to detect the molecular mechanism by which miR-378a-3p inhibits angiogenesis. Results We confirmed that miR-378a-3p expression was significantly downregulated and associated with higher microvascular density (MVD) in HCC; miR-378a-3p downregulation indicated a short survival time in HCC patients. miR-378a-3p knockdown led to a significant increase in angiogenesis in vitro and in vivo. We found that miR-378a-3p directly targeted TNF receptor associated factor 1 (TRAF1) to attenuate NF-κB signaling, and then downregulated secreted vascular endothelial growth factor. DNA methyltransferase 1 (DNMT1)-mediated hypermethylation of miR-378a-3p was responsible for downregulating miR-378a-3p. Moreover, a series of investigations indicated that p65 initiated a positive feedback loop that could upregulate DNMT1 to promote hypermethylation of the miR-378a-3p promoter. Conclusion Our study indicates a novel DNMT1/miR-378a-3p/TRAF1/NF-κB positive feedback loop in HCC cells, which may become a potential therapeutic target for HCC.


2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Meng-Zhi Wu ◽  
Yi-chuan Yuan ◽  
Bi-Yu Huang ◽  
Jin-Xi Chen ◽  
Bin-Kui Li ◽  
...  

AbstractAberrant activation of the TGF-β/SMAD signaling pathway is often observed in hepatocellular carcinoma (HCC). Whether lncRNA regulates the TGF-β/SMAD signaling remains largely unknown. Here, we identified an oncogenic lncRNA that was upregulated in HCC and was transcriptionally induced by TGF-β (named lnc-UTGF, lncRNA upregulated by TGF-β). Upon TGF-β stimulation, SMAD2/3 bound to the lnc-UTGF promoter and activated lnc-UTGF expression. In turn, the TGF-β/SMAD signaling was augmented by overexpressing lnc-UTGF, but was inhibited by silencing lnc-UTGF. Mechanism investigations revealed that lnc-UTGF interacted with the mRNAs of SMAD2 and SMAD4 via complementary base-pairing, resulting in enhanced stability of SMAD2/4 mRNAs. These data suggest a novel TGF-β/SMAD/lnc-UTGF positive feedback circuitry. Subsequent gain- and loss-of-function analyses disclosed that lnc-UTGF promoted the migration and invasion of hepatoma cells, and this effect of lnc-UTGF was attenuated by repressing SMAD2/4 expression or by mutating the SMAD2/4-binding sites in lnc-UTGF. Studies using mouse models further confirmed that in vivo metastasis of hepatoma xenografts was inhibited by silencing lnc-UTGF, but was enhanced by ectopic expression of lnc-UTGF. The lnc-UTGF level was positively correlated with the SMAD2/4 levels in xenografts. Consistently, we detected an association of lnc-UTGF upregulation with increase of SMAD2, SMAD4, and their metastasis effector SNAIL1 in human HCC. And high lnc-UTGF level was also significantly associated with enhanced metastasis potential, advanced TNM stages, and worse recurrence-free survival. Conclusion: there exists a lnc-UTGF-mediated positive feedback loop of the TGF-β signaling and its deregulation promotes hepatoma metastasis. These findings may provide a new therapeutic target for HCC metastasis.


2021 ◽  
Author(s):  
Shouping Xu ◽  
Lin Wan ◽  
Qin Wang ◽  
Huizi Yin ◽  
Kun Qiao ◽  
...  

Abstract Background: The oncogenic lncRNA based strategies for combating cancer may usher in a new and promising paradigm in cancer therapy. However, few studies have been performed to solve such a critical issue. The complex traits and molecular mechanism of such lncRNAs in tumorigenesis and their relationship with sensitivity of gefitinib in human cancer have not been investigated.Methods: We aimed to identify and validate such a novel oncogenic LINC00036 using transcriptome sequencing approach and a large number of tissue samples of different types of cancer from the our cancer center cohort and public data cohorts from the Cancer Genome Atlas,Gene Expression Omnibus and Cancer Cell Line Encyclopedia. Moreover, series of in vitro and in vivo experiments were performed to examine its roles in tumorigenesis and the sensitivity of gefitinib in different types of cancer cells. Special nanoparticle via a more potent delivery system was developed to investigate the feasibility of targeting LINC00036 in vivo. Furthermore, chromatin immunoprecipitation (ChIP)-sequencing, ChIP, actinomycin D assay, dual-luciferase reporter assay, RNA pull-down and RNA immunoprecipitation were performed were developed to uncover the molecular mechanism.Results: LINC00036 that associated with poor prognosis is significantly upregulated in human cancer tissues. Series of in vitro and in vivo experiments reveal that LINC00036 promotes tumorigenesis and decreases the sensitivity of gefitinib in different types of cancer cells. LINC00036 targeting nanoparticle markedly reduced the growth of human cancer xenografts. Mechanistically, LINC00036 is a direct transcriptional target of c-MYC and a positive feedback loop of the c-MYC-LINC00036-EGFR axis exists in human cancer. LINC00036 acts as an EGFR mRNA stabilizer via RNA-protein and RNA-RNA interactions, inducing the hyper-activation of the downstream AKT and MAPK signaling pathways, which in turn decreases the sensitivity of gefitinib in human cancer.Conclusions: LINC00036, a c-MYC inducible onco-lncRNA, acts an oncogene in human cancer and decreases the sensitivity of gefitinib through positive feedback loop of the c-MYC-LINC00036-EGFR axis. Overall, this study broadens knowledge regarding novel onco-lncRNAs and will assist in developing feasible onco-lncRNAs based-targeted therapeutic strategies to improve the sensitivity of gefitinib in human cancer.


2020 ◽  
Author(s):  
Yiwen Xia ◽  
Jialun Lv ◽  
Tianlu Jiang ◽  
Bowen Li ◽  
Zhongyuan He ◽  
...  

Abstract Background: Circular RNAs (circRNAs) have emerged as a new subclass of regulatory RNAs that exert critical roles in various cancers. Cancer stem cells (CSCs), a small subset of cancer cells, are believed to possess the capacities to initiate tumorigenesis and promote progression. Although accumulating evidences have suggested that cells with CSC-like properties are crucial for the malignance process of gastric cancer (GC), it remains inexplicit whether circRNAs are interrelated with the acquisition of CSC-like properties in GC.Methods: circFAM73A expression was analyzed by GEO datasets and verified in GC samples. The role of circFAM73A on GC cell proliferation, migration, cisplatin resistance and CSC-like properties were determined by a series of functional experiment both in vitro and in vivo. RNA pull down was used to explore the miRNAs and proteins binding to circFAM73A. Bioinformatic analysis and experimental verification confirmed the downstream of circFAM73A. The regulation of HMGA2 on circFAM73A was verified by ChIP and RIP assays.Results: Elevated circFAM73A expression was confirmed in GC tissues and higher circFAM73A predicts poor prognosis of GC patients. The upregulation of circFAM73A enhanced CSC-like properties in GC, thus, exerting the facilitating role on cell proliferation, migration and cisplatin resistance. Mechanistically, circFAM73A promoted GC malignancy by regulating miR-490-3p/HMGA2 in a positive feedback loop and recruiting HNRNPK to facilitate β-catenin stabilization. Moreover, HMGA2 further enhanced E2F1 and HNRNPL activity, which in turn promotes circFAM73A expression.Conclusions: Our work demonstrates the crucial role of circFAM73A on GC CSC-like properties and uncovers a positive feedback loop on circFAM73A regulation that leads to the progression of gastric cancer, which may provide a new insight for circRNA-based diagnostic and therapeutic strategies.


2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Xu Liu ◽  
Fei Ma ◽  
Chunxiao Liu ◽  
Kaiyuan Zhu ◽  
Wenjie Li ◽  
...  

AbstractUbiquitin-conjugating enzyme E2O (UBE2O) is a large E2 ubiquitin-conjugating enzyme that possesses both E2 and E3 ligase activities. Ectopic UBE2O overexpression is associated with a variety of human diseases, especially cancers. However, the expression profile and functional biology of UBE2O in human breast cancer (BC) remain unclear. In this study, we found that UBE2O was significantly overexpressed in human BC tissues and cells. Patients with high UBE2O expression tended to have a high risk of metastasis and poor prognosis. In vitro assays revealed that UBE2O promoted BC cell proliferation and epithelial–mesenchymal transformation (EMT) and endowed BC cells with cancer stemness properties (CSPs). UBE2O knockdown in MDA-MB-231 cells suppressed tumour growth and lung metastasis in MDA-MB-231 xenograft mouse models. Mechanistically, UBE2O functioned as a ubiquitin enzyme of AMPKα2, promoting its ubiquitination and degradation and thus activating the mTORC1 signal pathway and contributing to BC oncogenesis and metastasis. Furthermore, as a downstream factor of the UBE2O/AMPKα2/mTORC1 axis, the oncoprotein MYC transcriptionally promoted UBE2O and formed a positive feedback loop in human BC. Collectively, our study demonstrated that UBE2O/AMPKα2/mTORC1-MYC forms a positive feedback loop in human BC cells that regulates BC cell proliferation and EMT and endows BC cells with CSPs.


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