scholarly journals circFAM73A Promotes Cancer Stem Cell-like Properties of Gastric Cancer Through miR-490-3p/HMGA2 Positive Feedback and HNRNPK-mediated β-catenin Stabilization.

2020 ◽  
Author(s):  
Yiwen Xia ◽  
Jialun Lv ◽  
Tianlu Jiang ◽  
Bowen Li ◽  
Zhongyuan He ◽  
...  
Keyword(s):  
Gastric Cancer ◽  
Cell Proliferation ◽  
Positive Feedback ◽  
Feedback Loop ◽  
Cisplatin Resistance ◽  
Circular Rnas ◽  
Small Subset ◽  
Positive Feedback Loop

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.

scholarly journals CircFAM73A promotes the cancer stem cell-like properties of gastric cancer through the miR-490-3p/HMGA2 positive feedback loop and HNRNPK-mediated β-catenin stabilization

2021 ◽  
Vol 40 (1) ◽  
Author(s):  
Yiwen Xia ◽  
Jialun Lv ◽  
Tianlu Jiang ◽  
Bowen Li ◽  
Ying Li ◽  
...  
Keyword(s):  
Gastric Cancer ◽  
Cell Proliferation ◽  
Positive Feedback ◽  
Feedback Loop ◽  
Cisplatin Resistance ◽  
Circular Rnas ◽  
Small Subset ◽  
Positive Feedback Loop

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.

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

2021 ◽  
Vol 40 (1) ◽  
Author(s):  
Jin-Chun Qi ◽  
Zhan Yang ◽  
Tao Lin ◽  
Long Ma ◽  
Ya-Xuan Wang ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Transcriptional Activation ◽  
Positive Feedback ◽  
Feedback Loop ◽  
Biological Effects ◽  
Therapeutic Benefit ◽  
Loss Of Function ◽  
Positive Feedback Loop

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.

scholarly journals UBE2O promotes the proliferation, EMT and stemness properties of breast cancer cells through the UBE2O/AMPKα2/mTORC1-MYC positive feedback loop

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Xu Liu ◽  
Fei Ma ◽  
Chunxiao Liu ◽  
Kaiyuan Zhu ◽  
Wenjie Li ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cell Proliferation ◽  
Positive Feedback ◽  
Feedback Loop ◽  
In Vitro Assays ◽  
Positive Feedback Loop ◽  
Ubiquitin Conjugating Enzyme ◽  
Mesenchymal Transformation ◽  
Conjugating Enzyme

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.

scholarly journals IRE1α Expedites the Progression of Castration-Resistant Prostate Cancers via the Positive Feedback Loop of IRE1α/IL-6/AR

2021 ◽  
Vol 11 ◽  
Author(s):  
Fan Yang ◽  
Chong Yuan ◽  
Dan Wu ◽  
Jing Zhang ◽  
Xingchun Zhou
Keyword(s):  
Prostate Cancer ◽  
Cell Proliferation ◽  
Positive Feedback ◽  
Feedback Loop ◽  
Castration Resistant Prostate Cancer ◽  
Positive Feedback Loop ◽  
Castration Resistant ◽  
Prostate Cancers

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.

scholarly journals A positive-feedback loop between HBx and ALKBH5 promotes hepatocellular carcinogenesis

BMC Cancer ◽  
2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Siming Qu ◽  
Li Jin ◽  
Hanfei Huang ◽  
Jie Lin ◽  
Weiwu Gao ◽  
...  
Keyword(s):  
Positive Feedback ◽  
Feedback Loop ◽  
Hbv Infection ◽  
Cell Counting ◽  
Regulation Mechanism ◽  
Dependent Manner ◽  
Liver Carcinogenesis ◽  
Nude Mouse Model ◽  
Positive Feedback Loop

Abstract Background Hepatitis B Virus (HBV) contributes to liver carcinogenesis via various epigenetic mechanisms. The newly defined epigenetics, epitranscriptomics regulation, has been reported to involve in multiple cancers including Hepatocellular Carcinoma (HCC). Our previous study found that HBx, HBV encodes X protein, mediated H3K4me3 modification in WDR5-dependent manner to involve in HBV infection and contribute to oncogene expression. AlkB Homolog 5 (ALKBH5), one of epitranscriptomics enzymes, has been identified to be associated with various cancers. However, whether and how ALKBH5 is dysregulated in HBV-related HCC remains unclear yet. This study aims to investigate ALKBH5 function, clinical significance and mechanism in HBV related HCC (HBV-HCC) patients derived from Chinese people. Methods The expression pattern of ALKBH5 was evaluated by RT-qPCR, Western blot, data mining and immunohistochemistry in total of 373 HBV-HCC tissues and four HCC cell lines. Cell Counting Kit 8 (CCK8) assay, Transwell and nude mouse model were performed to assess ALKBH5 function by both small interference RNAs and lentiviral particles. The regulation mechanism of ALKBH5 was determined in HBx and WDR5 knockdown cells by CHIP-qPCR. The role of ALKBH5 in HBx mRNA N6-methyladenosine (m6A) modification was further evaluated by MeRIP-qPCR and Actinomycin D inhibitor experiment in HBV-driven cells and HBx overexpression cells. Result ALKBH5 increased in tumor tissues and predicts a poor prognosis of HBV-HCC. Mechanically, the highly expressed ALKBH5 is induced by HBx-mediated H3K4me3 modification of ALKBH5 gene promoter in a WDR5-dependent manner after HBV infection. The increased ALKBH5 protein catalyzes the m6A demethylation of HBx mRNA, thus stabilizing and favoring a higher HBx expression level. Furthermore, there are positive correlations between HBx and ALKBH5 in HBV-HCC tissues, and depletion of ALKBH5 significantly inhibits HBV-driven tumor cells’ growth and migration in vitro and in vivo. Conclusions HBx-ALKBH5 may form a positive-feedback loop to involve in the HBV-induced liver carcinogenesis, and targeting the loop at ALKBH5 may provide a potential way for HBV-HCC treatment.

scholarly journals THAP9-AS1/miR-133b/SOX4 positive feedback loop facilitates the progression of esophageal squamous cell carcinoma

2021 ◽  
Vol 12 (4) ◽  
Author(s):  
Jiwei Cheng ◽  
Haibo Ma ◽  
Ming Yan ◽  
Wenqun Xing
Keyword(s):  
Squamous Cell Carcinoma ◽  
Esophageal Squamous Cell Carcinoma ◽  
Cell Carcinoma ◽  
Squamous Cell ◽  
Positive Feedback ◽  
Feedback Loop ◽  
Malignant Tumors ◽  
Migration And Invasion ◽  
Positive Feedback Loop

AbstractEsophageal squamous cell carcinoma (ESCC) is one of the most common malignant tumors in the digestive system with a high incidence and poor prognosis. Long non-coding RNAs (LncRNA) have been reported to be closely associated with the occurrence and development of various human cancers. Data from GSE89102 shows an increase of THAP9-AS1 expression in ESCC. However, its functions and mechanisms underlying ESCC progression remain to be investigated. In this study, we found that THAP9-AS1 was overexpressed in ESCC tissues and cells. High THAP9-AS1 expression was positively correlated with tumor size, TNM stage, lymph node metastasis, and worse prognosis. Functionally, depletion of THAP9-AS1 suppressed cell proliferation, migration, and invasion, while enhanced apoptosis in vitro. Consistently, knockdown of THAP9-AS1 inhibited xenograft tumor growth in vivo. Mechanistically, THAP9-AS1 could serve as a competing endogenous RNA (ceRNA) for miR-133b, resulting in the upregulation of SOX4. Reciprocally, SOX4 bound to the promoter region of THAP9-AS1 to activate its transcription. Moreover, the anti-tumor property induced by THAP9-AS1 knockdown was significantly impaired due to miR-133b downregulation or SOX4 overexpression. Taken together, our study reveals a positive feedback loop of THAP9-AS1/miR-133b/SOX4 to facilitate ESCC progression, providing a potential molecular target to fight against ESCC.

scholarly journals The Dickkopf1 and FOXM1 positive feedback loop promotes tumor growth in pancreatic and esophageal cancers

Oncogene ◽  
2021 ◽  
Author(s):  
Hirokazu Kimura ◽  
Ryota Sada ◽  
Naoki Takada ◽  
Akikazu Harada ◽  
Yuichiro Doki ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Wnt Signaling ◽  
Cancer Cell ◽  
Positive Feedback ◽  
Feedback Loop ◽  
Ductal Adenocarcinoma ◽  
Cancer Cell Proliferation ◽  
Positive Feedback Loop ◽  
Dkk1 Expression ◽  
Foxm1 Expression

AbstractDickkopf1 (DKK1) is overexpressed in various cancers and promotes cancer cell proliferation by binding to cytoskeleton-associated protein 4 (CKAP4). However, the mechanisms underlying DKK1 expression are poorly understood. RNA sequence analysis revealed that expression of the transcription factor forkhead box M1 (FOXM1) and its target genes concordantly fluctuated with expression of DKK1 in pancreatic ductal adenocarcinoma (PDAC) cells. DKK1 knockdown decreased FOXM1 expression and vice versa in PDAC and esophageal squamous cell carcinoma (ESCC) cells. Inhibition of either the DKK1-CKAP4-AKT pathway or the ERK pathway suppressed FOXM1 expression, and simultaneous inhibition of both pathways showed synergistic effects. A FOXM1 binding site was identified in the 5ʹ-untranslated region of the DKK1 gene, and its depletion decreased DKK1 expression and cancer cell proliferation. Clinicopathological and database analysis revealed that PDAC and ESCC patients who simultaneously express DKK1 and FOXM1 have a poorer prognosis. Multivariate analysis demonstrated that expression of both DKK1 and FOXM1 is the independent prognostic factor in ESCC patients. Although it has been reported that FOXM1 enhances Wnt signaling, FOXM1 induced DKK1 expression independently of Wnt signaling in PDAC and ESCC cells. These results suggest that DKK1 and FOXM1 create a positive feedback loop to promote cancer cell proliferation.

Knockdown of PGM1 Synergistically Enhances Anticancer Effects of Orlistat in Gastric Cancer Under Glucose Deprivation

2021 ◽  
Author(s):  
Bo Cao ◽  
Huan Deng ◽  
Hao Cui ◽  
Ruiyang Zhao ◽  
Hanghang Li ◽  
...  
Keyword(s):  
Gastric Cancer ◽  
Cell Proliferation ◽  
Lipid Metabolism ◽  
Fatty Acid Synthase ◽  
Enrichment Analysis ◽  
Glucose Deprivation ◽  
Metabolic Reprogramming ◽  
The Cancer Genome Atlas

Abstract Background Phosphoglucomutase 1 (PGM1) acts as an important regulator in glucose metabolism. However, the role of PGM1 in gastric cancer (GC) remains unclear. This study aims to investigate the role of PGM1 and develop novel regimens based on metabolic reprogramming in GC. MethodsCorrelation and enrichment analysis of PGM1 was conducted based on The Cancer Genome Atlas database. Data derived from the Kaplan-Meier Plotter database were analyzed for correlations between PGM1 expression and survival time of GC patients. CCK-8, EdU, flow cytometry assays, generation of subcutaneous tumor and lung metastasis mouse models were used to determine growth and metastasis in vitro and in vivo. Cell glycolysis was detected by a battery of glycolytic indicators, including lactate, pyruvic acid, ATP production and glucose uptake. Fatty Acid Synthase (FASN) activity and detection of lipid regulators levels by western blot were used to reflect on the cell lipid metabolism. ResultsCorrelation and enrichment analysis suggested that PGM1 was closely associated with cell proliferation and metabolism. PGM1 was overexpressed in GC tissues and cell lines. High PGM1 expression served as an indicator of shorter survival for specific subpopulation of GC patients, which was also correlated with some clinicopathological features, including T stage and TNM stage. Under low glucose conditions, knockdown of PGM1 significantly suppressed cell proliferation and glycolysis levels, whereas lipid metabolism was enhanced. Orlistat, as a drug that was designed to inhibit FASN activity for obesity treatment, effectively induced apoptosis, suppressed FASN activity. However, orlistat conversely increased glycolytic levels in GC cells. Orlistat exhibited more significant inhibitive effects on GC progression after knockdown of PGM1 under glucose deprivation due to combination of glycolysis and lipid metabolism. ConclusionsDownregulation of PGM1 expression under glucose deprivation synergistically enhanced anti-cancer effects of orlistat. This combination application may serve as a novel strategy for GC treatment.

P53/miR-34a/SIRT1 Positive Feedback Loop regulates cell proliferation and promotes cell apoptosis in the termination stage of liver regeneration.

2021 ◽  
Author(s):  
Junhua Gong ◽  
Minghua Cong ◽  
Hao Wu ◽  
Menghao Wang ◽  
He Bai ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Liver Regeneration ◽  
Positive Feedback ◽  
Cell Apoptosis ◽  
Feedback Loop ◽  
Late Phase ◽  
Liver Weight ◽  
Positive Feedback Loop ◽  
And Function ◽  
Shed Light

Abstract Background The capacity of the liver to restore its architecture and function assures good prognoses of patients who suffer serious hepatic injury or cancer resection. In our study, we found that the P53/miR-34a/SIRT1 positive feedback loop has a remarkable negative regulatory effect, which is related to the termination of liver regeneration. Here, we described how P53/miR-34a/SIRT1 positive feedback loop controls liver regeneration and its possible relationship with liver cancer.Method We performed partial hepatectomy (PH) in mice transfected with adenovirus (Ade) overexpressing P53 and adenovirus-associated virus (AAV) knock-downing miR-34a. LR was analyzed by liver weight/body weight, serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels and cell proliferation, and the related cellular signals were investigated. Bile acid (BA) levels during LR were analyzed by metabolomics of bile acids. Results We found that the P53/miR-34a/SIRT1 positive feedback loop was activated in the late phase of LR. Overexpression of P53 terminated LR early and enhanced P53/miR-34a/SIRT1 positive feedback loop expression and its proapoptotic effect. Mice from the Ade-P53 group showed smaller livers and higher levels of serum ALT and AST than control mice. While knock-down of miR-34a abolished P53/miR-34a/SIRT1 positive feedback loop during LR. Mice from anti-miR-34a group showed larger livers and lower levels of PCNA-positive cells than control mice. T-β-MCA increased gradually during LR and peaked at 7 days after PH. T-β-MCA inhibited cell proliferation and promoted cell apoptosis via facilitating the P53/miR-34a/SIRT1 positive feedback loop during LR by suppressing FXR/SHP. Conclusion The P53/miR-34a/SIRT1 positive feedback loop plays an important role in the termination of LR. Our findings shed light on the molecular and metabolic mechanisms of LR termination and provide a potential therapeutic alternative for treating P53-wild-type HCC patients.

scholarly journals Autocrine signaling by an Aplysia neurotrophin forms a presynaptic positive feedback loop

2018 ◽  
Vol 115 (47) ◽  
pp. E11168-E11177 ◽  
Author(s):  
Iksung Jin ◽  
Hiroshi Udo ◽  
Russell Nicholls ◽  
Huixiang Zhu ◽  
Eric R. Kandel ◽  
...  
Keyword(s):  
Positive Feedback ◽  
Feedback Loop ◽  
Autocrine Signaling ◽  
Positive Feedback Loop ◽  
Short Term Plasticity ◽  
Extracellular Signaling ◽  
Presynaptic Protein ◽  
Long Term Facilitation

Whereas short-term plasticity is often initiated on one side of the synapse, long-term plasticity involves coordinated changes on both sides, implying extracellular signaling. We have investigated the possible signaling role of an Aplysia neurotrophin (ApNT) in facilitation induced by serotonin (5HT) at sensory-to-motor neuron synapses in culture. ApNT is an ortholog of mammalian BDNF, which has been reported to act as either an anterograde, retrograde, or autocrine signal, so that its pre- and postsynaptic sources and targets remain unclear. We now report that ApNT acts as a presynaptic autocrine signal that forms part of a positive feedback loop with ApTrk and PKA. That loop stimulates spontaneous transmitter release, which recruits postsynaptic mechanisms, and presynaptic protein synthesis during the transition from short- to intermediate-term facilitation and may also initiate gene regulation to trigger the transition to long-term facilitation. These results suggest that a presynaptic ApNT feedback loop plays several key roles during consolidation of learning-related synaptic plasticity.

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