scholarly journals A novel AP-1/miR-101 regulatory feedback loop and its implication in the migration and invasion of hepatoma cells

2014 ◽  
Vol 42 (19) ◽  
pp. 12041-12051 ◽  
Author(s):  
Jing-Jing Liu ◽  
Xue-Jia Lin ◽  
Xiao-Jing Yang ◽  
Liangji Zhou ◽  
Shuai He ◽  
...  
Keyword(s):  
Feedback Loop ◽  
Hepatoma Cells ◽  
Migration And Invasion ◽  
Regulatory Feedback Loop

scholarly journals HIF-3α-Induced miR-630 Expression Promotes Cancer Hallmarks in Cervical Cancer Cells by Forming a Positive Feedback Loop

2021 ◽  
Author(s):  
Qiaohui Gao ◽  
Zhenghua Ren ◽  
Shengyuan Jiao ◽  
Juan Guo ◽  
Xia Miao ◽  
...  
Keyword(s):  
Cervical Cancer ◽  
Cancer Cells ◽  
Feedback Loop ◽  
Migration And Invasion ◽  
Rna Seq ◽  
Cancer Hallmarks ◽  
Potential Biomarker ◽  
Cervical Cancer Cells ◽  
Regulatory Feedback Loop ◽  
Cervical Cancer Development

Abstract Background Hypoxia has crucial functions in cervical cancer development and metastasis by inducing the level of numerous genes, including microRNA genes. But we know little about how the hypoxia factors and microRNAs orchestrate to regulate hallmarks of cervical cancer cells. Methods We used RNA sequencing (RNA-seq) and chromatin immunoprecipitation sequencing experiments (ChIP-seq) to investigate the targets of HIF-3α or miR-630. ChIP-qPCR and RT-qPCR were used to validate the sequencing results of ChIP-seq and RNA-seq. Cellular, molecular and radiation experiments were used to explore the functions of miR-630.Results Here, we show that hypoxia-induced overexpression HIF-3α increased the expression of dozens of miRNAs, including miR-630. Further experiment showed the activation of miR-630 was induced by hypoxia treatment. We showed that hypoxia induces expression of HIF-3α to activate miR-630 expression by directly binding to its promoter. Meanwhile, miR-630 positively regulates HIF-1α expression, but represses HIF-1α. Stable overexpression of miR-630 in HeLa cells promotes cancer hallmarks, including radioresistance, inhibition of apoptosis, increased migration and invasion, and EMT-mediated metastasis. Stable inhibition of miR-630 showed opposite features. Conclusion Taken together, our findings implicate a novel hypoxia-induced HIF3a-miR-630 regulatory feedback loop contributing to metastasis and progression of cervical cancer cells, and suggest HIF3a and miR630 might be applied as a potential biomarker and therapeutic target for cervical cancer.

scholarly journals HDAC8 cooperates with SMAD3/4 complex to suppress SIRT7 and promote cell survival and migration

2020 ◽  
Vol 48 (6) ◽  
pp. 2912-2923 ◽  
Author(s):  
Xiaolong Tang ◽  
Guo Li ◽  
Fengting Su ◽  
Yanlin Cai ◽  
Lei Shi ◽  
...  
Keyword(s):  
Ribosome Biogenesis ◽  
Feedback Loop ◽  
Therapeutic Potential ◽  
Genome Integrity ◽  
Migration And Invasion ◽  
Promote Cell Survival ◽  
Regulatory Feedback Loop ◽  
And Migration ◽  
Multicellular Organisms ◽  
Chemotherapy Efficacy

Abstract NAD+-dependent SIRT7 deacylase plays essential roles in ribosome biogenesis, stress response, genome integrity, metabolism and aging, while how it is transcriptionally regulated is still largely unclear. TGF-β signaling is highly conserved in multicellular organisms, regulating cell growth, cancer stemness, migration and invasion. Here, we demonstrate that histone deacetylase HDAC8 forms complex with SMAD3/4 heterotrimer and occupies SIRT7 promoter, wherein it deacetylates H4 and thus suppresses SIRT7 transcription. Treatment with HDAC8 inhibitor compromises TGF-β signaling via SIRT7-SMAD4 axis and consequently, inhibits lung metastasis and improves chemotherapy efficacy in breast cancer. Our data establish a regulatory feedback loop of TGF-β signaling, wherein HDAC8 as a novel cofactor of SMAD3/4 complex, transcriptionally suppresses SIRT7 via local chromatin remodeling and thus further activates TGF-β signaling. Targeting HDAC8 exhibits therapeutic potential for TGF-β signaling related diseases.

Novel players fine-tune plant trade-offs

2015 ◽  
Vol 58 ◽  
pp. 83-100 ◽  
Author(s):  
Selena Gimenez-Ibanez ◽  
Marta Boter ◽  
Roberto Solano
Keyword(s):  
Ubiquitin Ligase ◽  
Feedback Loop ◽  
Molecular Level ◽  
26S Proteasome ◽  
Signalling Molecules ◽  
Transcriptional Reprogramming ◽  
Trade Offs ◽  
Jaz Proteins ◽  
Regulatory Feedback Loop ◽  
Fine Tune

Jasmonates (JAs) are essential signalling molecules that co-ordinate the plant response to biotic and abiotic challenges, as well as co-ordinating several developmental processes. Huge progress has been made over the last decade in understanding the components and mechanisms that govern JA perception and signalling. The bioactive form of the hormone, (+)-7-iso-jasmonyl-l-isoleucine (JA-Ile), is perceived by the COI1–JAZ co-receptor complex. JASMONATE ZIM DOMAIN (JAZ) proteins also act as direct repressors of transcriptional activators such as MYC2. In the emerging picture of JA-Ile perception and signalling, COI1 operates as an E3 ubiquitin ligase that upon binding of JA-Ile targets JAZ repressors for degradation by the 26S proteasome, thereby derepressing transcription factors such as MYC2, which in turn activate JA-Ile-dependent transcriptional reprogramming. It is noteworthy that MYCs and different spliced variants of the JAZ proteins are involved in a negative regulatory feedback loop, which suggests a model that rapidly turns the transcriptional JA-Ile responses on and off and thereby avoids a detrimental overactivation of the pathway. This chapter highlights the most recent advances in our understanding of JA-Ile signalling, focusing on the latest repertoire of new targets of JAZ proteins to control different sets of JA-Ile-mediated responses, novel mechanisms of negative regulation of JA-Ile signalling, and hormonal cross-talk at the molecular level that ultimately determines plant adaptability and survival.

scholarly journals miR-29a sensitizes the response of glioma cells to temozolomide by modulating the P53/MDM2 feedback loop

2021 ◽  
Vol 26 (1) ◽  
Author(s):  
Qiudan Chen ◽  
Weifeng Wang ◽  
Shuying Chen ◽  
Xiaotong Chen ◽  
Yong Lin
Keyword(s):  
Molecular Mechanism ◽  
Feedback Loop ◽  
Glioma Cells ◽  
Luciferase Reporter ◽  
Migration And Invasion ◽  
Transcriptional Level ◽  
Aberrant Expression ◽  
Altered Expression ◽  
P53 Signaling

AbstractRecently, pivotal functions of miRNAs in regulating common tumorigenic processes and manipulating signaling pathways in brain tumors have been recognized; notably, miR‐29a is closely associated with p53 signaling, contributing to the development of glioma. However, the molecular mechanism of the interaction between miR-29a and p53 signaling is still to be revealed. Herein, a total of 30 glioma tissues and 10 non-cancerous tissues were used to investigate the expression of miR‐29a. CCK-8 assay and Transwell assay were applied to identify the effects of miR-29a altered expression on the malignant biological behaviors of glioma cells in vitro, including proliferation, apoptosis, migration and invasion. A dual-luciferase reporter assay was used to further validate the regulatory effect of p53 or miR-29a on miR-29a or MDM2, respectively, at the transcriptional level. The results showed that miR-29a expression negatively correlated with tumor grade of human gliomas; at the same time it inhibited cell proliferation, migration, and invasion and promoted apoptosis of glioma cells in vitro. Mechanistically, miR-29a expression was induced by p53, leading to aberrant expression of MDM2 targeted by miR-29a, and finally imbalanced the activity of the p53-miR-29a-MDM2 feedback loop. Moreover, miR-29a regulating p53/MDM2 signaling sensitized the response of glioma cells to temozolomide treatment. Altogether, the study demonstrated a potential molecular mechanism in the tumorigenesis of glioma, while offering a possible target for treating human glioma in the future.

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 RpoS-Dependent Transcriptional Control ofsprE: Regulatory Feedback Loop

2001 ◽  
Vol 183 (20) ◽  
pp. 5974-5981 ◽  
Author(s):  
Natividad Ruiz ◽  
Celeste N. Peterson ◽  
Thomas J. Silhavy
Keyword(s):  
Escherichia Coli ◽  
Stationary Phase ◽  
Intergenic Region ◽  
Feedback Loop ◽  
Transcriptional Control ◽  
Response Regulator ◽  
Phase Response ◽  
Specific Regulation ◽  
Regulatory Feedback Loop

ABSTRACT The stationary-phase response exhibited by Escherichia coli upon nutrient starvation is mainly induced by a decrease of the ClpXP-dependent degradation of the alternate primary ς factor RpoS. Although it is known that the specific regulation of this proteolysis is exercised by the orphan response regulator SprE, it remains unclear how SprE's activity is regulated in vivo. Previous studies have demonstrated that the cellular content of SprE itself is paradoxically increased in stationary-phase cells in an RpoS-dependent fashion. We show here that this RpoS-dependent upregulation of SprE levels is due to increased transcription. Furthermore, we demonstrate that sprE is part of the two-generssA-sprE operon, but it can also be transcribed from an additional RpoS-dependent promoter located in therssA-sprE intergenic region. In addition, by using an in-frame deletion in rssA we found that RssA does not regulate either SprE or RpoS under the conditions tested.

scholarly journals Reciprocal Regulation of Brain and Muscle Arnt-Like Protein 1 and Peroxisome Proliferator-Activated Receptor α Defines a Novel Positive Feedback Loop in the Rodent Liver Circadian Clock

2006 ◽  
Vol 20 (8) ◽  
pp. 1715-1727 ◽  
Author(s):  
Laurence Canaple ◽  
Juliette Rambaud ◽  
Ouria Dkhissi-Benyahya ◽  
Béatrice Rayet ◽  
Nguan Soon Tan ◽  
...  
Keyword(s):  
Gene Expression ◽  
Circadian Rhythm ◽  
Feedback Loop ◽  
Clock Gene ◽  
Peroxisome Proliferator ◽  
Peroxisome Proliferator Activated Receptor ◽  
Reciprocal Regulation ◽  
Clock Gene Expression ◽  
Regulatory Feedback Loop

Abstract Recent evidence has emerged that peroxisome proliferator-activated receptor α (PPARα), which is largely involved in lipid metabolism, can play an important role in connecting circadian biology and metabolism. In the present study, we investigated the mechanisms by which PPARα influences the pacemakers acting in the central clock located in the suprachiasmatic nucleus and in the peripheral oscillator of the liver. We demonstrate that PPARα plays a specific role in the peripheral circadian control because it is required to maintain the circadian rhythm of the master clock gene brain and muscle Arnt-like protein 1 (bmal1) in vivo. This regulation occurs via a direct binding of PPARα on a potential PPARα response element located in the bmal1 promoter. Reversely, BMAL1 is an upstream regulator of PPARα gene expression. We further demonstrate that fenofibrate induces circadian rhythm of clock gene expression in cell culture and up-regulates hepatic bmal1 in vivo. Together, these results provide evidence for an additional regulatory feedback loop involving BMAL1 and PPARα in peripheral clocks.

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