Common Therapeutic Target Research Articles

Molecular mechanism of setron-mediated inhibition of full-length 5-HT3A receptor

Serotonin receptor (5-HT3AR) is the most common therapeutic target to manage the nausea and vomiting during cancer therapies and in the treatment of irritable bowel syndrome. Setrons, a class of competitive antagonists, cause functional inhibition of 5-HT3AR in the gastrointestinal tract and brainstem, acting as effective anti-emetic agents. Despite their prevalent use, the molecular mechanisms underlying setron binding and inhibition of 5-HT3AR are not fully understood. Here, we present the structure of granisetron-bound full-length 5-HT3AR solved by single-particle cryo-electron microscopy to 2.92 Å resolution. The reconstruction reveals the orientation of granisetron in the orthosteric site with unambiguous density for interacting sidechains. Molecular dynamics simulations and electrophysiology confirm the granisetron binding orientation and the residues central for ligand recognition. Comparison of granisetron-bound 5-HT3AR with the apo and serotonin-bound structures, reveals key insights into the mechanism underlying 5-HT3AR inhibition.

Recurrent DMD Deletions Highlight Specific Role of Dp71 Isoform in Soft-Tissue Sarcomas.

Soft-tissue sarcomas (STS) are rare tumors whose oncogenesis remains unknown and for which no common therapeutic target has yet been identified. Analysis of 318 STS by CGH array evidenced a frequent deletion affecting the DMD gene (encoding dystrophin isoforms) in 16.5% of STS, including sarcomas with complex genomics, gastrointestinal tumors (GIST), and synovial sarcomas (SS). These deletions are significantly associated with metastatic progression, thus suggesting the role of DMD downregulation in the acquisition of aggressive phenotypes. We observed that targeted deletions of DMD were restricted to the 5’ region of the gene, which is responsible for the transcription of Dp427. Analysis of STS tumors and cell lines by RNA sequencing revealed that only the Dp71 isoform was widely expressed. Dp427 depletion had no effect on cell growth or migration. However, Dp71 inhibition by shRNA dramatically reduced the cell proliferation and clonogenicity of three STS cell lines, likely by altering the cell cycle progression through the G2/M-phase. Our work demonstrates that DMD deletions are not restricted to myogenic tumors and could be used as a biomarker for metastatic evolution in STS. Dp71 seems to play an essential role in tumor growth, thus providing a potential target for future STS treatments.

Identification of the Infrapatellar Branch of the Saphenous Nerve for Treatment Using a Peripheral Nerve Stimulator: A Technical Report.

The infrapatellar branch of the saphenous is becoming a common therapeutic target for the diagnosis and treatment of anterior knee pain. It is a nerve commonly injured during knee surgeries, resulting in neuroma formation and chronic neuropathic pain states, and can also transmit nociceptive input in patients with non-surgical anterior knee pain of multiple etiologies. After diagnosing infrapatellar saphenous neuralgia, the nerve is safely ablated using radiofrequency ablation, neurolytic solutions, and, most recently, cryoablation using the handheld iovera® cryoablation system (Myoscience, Inc. Fremont, CA). The iovera® technology benefits from procedural simplicity in that the nerve doesn’t specifically need to be identified and the described technique involves treating a long line over which the infrapatellar branch of the saphenous nerve is expected to course. However, there is significant variability in the course of the nerve and much of the area treated misses the actual location of the nerve, wasting time and potentially increasing patient discomfort and risk of complications. To address these limitations we endeavored to identify a way to more precisely treat the specific location of the nerve thereby optimizing treatment success and procedural simplicity. Using a MiniStim® peripheral nerve stimulator (Halyard Health, Inc., Georgia, US) to scan for the nerve along the previously described treatment line, we have been able to identify a more precise location of the nerve and optimize the treatment target area. This non-invasive identification technique has, to our knowledge, not been previously described.

E6 proteins from high-risk HPV, low-risk HPV, and animal papillomaviruses activate the Wnt/β-catenin pathway through E6AP-dependent degradation of NHERF1.

High-risk human papillomavirus (HPV) E6 proteins associate with the cellular ubiquitin ligase E6-Associated Protein (E6AP), and then recruit both p53 and certain cellular PDZ proteins for ubiquitination and degradation by the proteasome. Low-risk HPV E6 proteins also associate with E6AP, yet fail to recruit p53 or PDZ proteins; their E6AP-dependent targets have so far been uncharacterized. We found a cellular PDZ protein called Na+/H+ Exchanger Regulatory Factor 1 (NHERF1) is targeted for degradation by both high and low-risk HPV E6 proteins as well as E6 proteins from diverse non-primate mammalian species. NHERF1 was degraded by E6 in a manner dependent upon E6AP ubiquitin ligase activity but independent of PDZ interactions. A novel structural domain of E6, independent of the p53 recognition domain, was necessary to associate with and degrade NHERF1, and the NHERF1 EB domain was required for E6-mediated degradation. Degradation of NHERF1 by E6 activated canonical Wnt/β-catenin signaling, a key pathway that regulates cell growth and proliferation. Expression levels of NHERF1 increased with increasing cell confluency. This is the first study in which a cellular protein has been identified that is targeted for degradation by both high and low-risk HPV E6 as well as E6 proteins from diverse animal papillomaviruses. This suggests that NHERF1 plays a role in regulating squamous epithelial growth and further suggests that the interaction of E6 proteins with NHERF1 could be a common therapeutic target for multiple papillomavirus types.

Upregulation of Mitofusin2 in neurons slows down skeletal muscles atrophy in ALS disease and aging model

Skeletal muscles undergo atrophy in response to diseases and aging. Mitochondria, the source of cellular energy, were found to be fragmented in experimental models of ALS disease and aging. However, whether and how mitochondrial fragmentation plays a role in the progression of disease and aging is not clear. Mitofusin2 (Mfn2) is a key regulator of mitochondrial fusion which is crucial for the maintenance of mitochondrial morphology. To test whether Mfn2 reduction in motor neurons contributed to the disease progression in SOD1G93A mice or aged mice, we generated transgenic mice overexpressing Mfn2 specifically in neurons under the control of the Thy1.2 promoter (TMFN mice). Mfn2 overexpression was confirmed in spinal cords but not skeletal muscles. By crossing Mfn2 overexpressed mice with SOD1G93A mice, we obtained double transgenic Mfn2/SOD1G93A mice. Interestingly, mitochondrial fragmentation was abolished in motor neurons of Mfn2/SOD1G93A mice even in the disease endstage. Strikingly, characteristic neuromuscular junction (NMJ) denervation, collapse, and dysfunction in SOD1G93A mice were also greatly alleviated in Mfn2/SOD1G93A mice. The dramatic protective effect of neuronal Mfn2 in SOD1G93A mice was further indicated by the greatly delayed symptom onset of more than 60 days and the complete prevention of behavioral deficits at 120 days old, a very late stage immediately before endstage onset.A similar protective effect was observed in aged mice. The Mfn2 neuronal overexpression mice suffered less neuromuscular synaptic dysfunction and skeletal muscle atrophy than their non‐transgenic litter mates even at 22 months old, which in human years is equivalent to the 70s. Taken together, our study provides evidence suggesting that Mfn2 deficiency induced mitochondrial fragmentation in motor neurons is likely an important mechanism leading to NMJ dysfunction and skeletal muscle atrophy in ALS and aging, and that Mfn2 could be a common therapeutic target for skeletal muscle atrophy.Support or Funding InformationThis study is supported by grants from the US NIH (1R01NS097679 and 1R01NS089604), US Alzheimer's Association (AARG‐17‐499682), and US Association for Frontotemporal Degeneration and Alzheimer's Drug Discovery Foundation (20161206).This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Tryptophan metabolism as a common therapeutic target in cancer, neurodegeneration and beyond

L-Tryptophan (Trp) metabolism through the kynurenine pathway (KP) is involved in the regulation of immunity, neuronal function and intestinal homeostasis. Imbalances in Trp metabolism in disorders ranging from cancer to neurodegenerative disease have stimulated interest in therapeutically targeting the KP, particularly the main rate-limiting enzymes indoleamine-2,3-dioxygenase 1 (IDO1), IDO2 and tryptophan-2,3-dioxygenase (TDO) as well as kynurenine monooxygenase (KMO). However, although small-molecule IDO1 inhibitors showed promise in early-stage cancer immunotherapy clinical trials, a phase III trial was negative. This Review summarizes the physiological and pathophysiological roles of Trp metabolism, highlighting the vast opportunities and challenges for drug development in multiple diseases.

MTSS1/Src family kinase dysregulation underlies multiple inherited ataxias

The genetically heterogeneous spinocerebellar ataxias (SCAs) are caused by Purkinje neuron dysfunction and degeneration, but their underlying pathological mechanisms remain elusive. The Src family of nonreceptor tyrosine kinases (SFK) are essential for nervous system homeostasis and are increasingly implicated in degenerative disease. Here we reveal that the SFK suppressor Missing-in-metastasis (MTSS1) is an ataxia locus that links multiple SCAs. MTSS1 loss results in increased SFK activity, reduced Purkinje neuron arborization, and low basal firing rates, followed by cell death. Surprisingly, mouse models for SCA1, SCA2, and SCA5 show elevated SFK activity, with SCA1 and SCA2 displaying dramatically reduced MTSS1 protein levels through reduced gene expression and protein translation, respectively. Treatment of each SCA model with a clinically approved Src inhibitor corrects Purkinje neuron basal firing and delays ataxia progression in MTSS1 mutants. Our results identify a common SCA therapeutic target and demonstrate a key role for MTSS1/SFK in Purkinje neuron survival and ataxia progression.

Long noncoding RNA MALAT1 in exosomes drives regenerative function and modulates inflammation-linked networks following traumatic brain injury

BackgroundNeuroinflammation is a common therapeutic target for traumatic brain injury (TBI) due to its contribution to delayed secondary cell death and has the potential to occur for years after the initial insult. Exosomes from adipose-derived stem cells (hASCs) containing the long noncoding RNA MALAT1 are a novel, cell-free regenerative approach to long-term recovery after traumatic brain injury (TBI) that have the potential to modulate inflammation at the genomic level. The long noncoding RNA MALAT1 has been shown to be an important component of the secretome of hASCs.MethodsWe isolated exosomes from hASC containing or depleted of MALAT1. The hASC-derived exosomes were then administered intravenously to rats following a mild controlled cortical impact (CCI). We followed the rats with behavior, in vivo imaging, histology, and RNA sequencing (RNA Seq).ResultsUsing in vivo imaging, we show that exosomes migrate into the spleen within 1 h following administration and enter the brain several hours later following TBI. Significant recovery of function on motor behavior as well as a reduction in cortical brain injury was observed after TBI in rats treated with exosomes. Treatment with either exosomes depleted of MALAT1 or conditioned media depleted of exosomes showed limited regenerative effects, demonstrating the importance of MALAT1 in exosome-mediated recovery. Analysis of the brain and spleen transcriptome using RNA Seq showed MALAT1-dependent modulation of inflammation-related pathways, cell cycle, cell death, and regenerative molecular pathways. Importantly, our data demonstrates that MALAT1 regulates expression of other noncoding RNAs including snoRNAs.ConclusionWe demonstrate that MALAT1 in hASC-derived exosomes modulates multiple therapeutic targets, including inflammation, and has tremendous therapeutic potential for treatment of TBI.

Mitofusin 2 Regulates Axonal Transport of Calpastatin to Prevent Neuromuscular Synaptic Elimination in Skeletal Muscles

Skeletal muscles undergo atrophy in response to diseases and aging. Here we report that mitofusin 2 (Mfn2) acts as a dominant suppressor of neuromuscular synaptic loss to preserve skeletal muscles. Mfn2 is reduced in spinal cords of transgenic SOD1G93A and aged mice. Through preserving neuromuscular synapses, increasing neuronal Mfn2 prevents skeletal muscle wasting in both SOD1G93A and aged mice, whereas deletion of neuronal Mfn2 produces neuromuscular synaptic dysfunction and skeletal muscle atrophy. Neuromuscular synaptic loss after sciatic nerve transection can also be alleviated by Mfn2. Mfn2 coexists with calpastatin largely in mitochondria-associated membranes (MAMs) to regulate its axonal transport. Genetic inactivation of calpastatin abolishes Mfn2-mediated protection of neuromuscular synapses. Our results suggest that, as a potential key component of a novel and heretofore unrecognized mechanism of cytoplasmic protein transport, Mfn2 may play a general role in preserving neuromuscular synapses and serve as a common therapeutic target for skeletal muscle atrophy.

CDC25 as a common therapeutic target for triple-negative breast cancer - the challenges ahead

ABSTRACTThe dual phosphatase CDC25 has recently been identified as a target for diverse triple-negative breast cancers including RB1/PTEN/P53-deficient tumors. Moreover, CDC25 inhibitors effectively synergize with PI3K inhibitors to suppress tumor growth. We discuss these findings and the challenges that lie ahead in bringing CDC25 inhibitors to the clinic.

Identification of CDC25 as a Common Therapeutic Target for Triple-Negative Breast Cancer

SUMMARYCDK4/6 inhibitors are effective against cancer cells expressing the tumor suppressor RB1, but not RB1-deficient cells, posing the challenge of how to target RB1 loss. In triple-negative breast cancer (TNBC), RB1 and PTEN are frequently inactivated together with TP53. We performed kinome/phosphatase inhibitor screens on primary mouse Rb/p53-, Pten/p53-, and human RB1/PTEN/TP53-deficient TNBC cell lines and identified CDC25 phosphatase as a common target. Pharmacological or genetic inhibition of CDC25 suppressed growth of RB1-deficient TNBC cells that are resistant to combined CDK4/6 plus CDK2 inhibition. Minimal cooperation was observed in vitro between CDC25 antagonists and CDK1, CDK2, or CDK4/6 inhibitors, but strong synergy with WEE1 inhibition was apparent. In accordance with increased PI3K signaling following long-term CDC25 inhibition, CDC25 and PI3K inhibitors effectively synergized to suppress TNBC growth both in vitro and in xenotransplantation models. These results provide a rationale for the development of CDC25-based therapies for diverse RB1/PTEN/TP53-deficient and -proficient TNBCs.

Pathologic conditions of hard tissue: role of osteoclasts in osteolytic lesion.

Hard tissue homeostasis is regulated by the balance between bone formation by osteoblasts and bone resorption by osteoclasts. This physiologic process allows adaptation to mechanical loading and calcium homeostasis. Under pathologic conditions, however, this process is ill-balanced resulting in either over-resorption or over-formation of hard tissue. Local over-resorption by osteoclasts is typically observed in osteolytic metastases of malignancies, autoimmune arthritis, and giant cell tumor of bone (GCTB). In tumor-related local osteolysis, tumor-derived osteoclast-activating factors induce bone resorption not by directly acting on osteoclasts but by indirectly upregulating receptor activator of NFκB ligand (RANKL) on osteoblastic cells. Similarly, synovial tissue in the autoimmune arthritis model does overexpress RANKL and contains numerous osteoclast precursors, and like a landing craft, when it comes in contact with eroded bone surfaces, osteoclast precursors are immediately polarized to become mature osteoclasts, inducing rapidly progressive bone destruction at a late stage of the disease. GCTB, on the other hand, is a common primary bone tumor, usually arising at the metaphysis of the long bone in young adults. After the discovery of RANKL, the concept of GCTB as a tumor of RANKL-expressing stromal cells was established, and comprehensive exosome studies finally disclosed the causative single-point mutation at histone H3.3 (H3F3A) in stromal cells. Thus, osteolytic lesions under various pathological conditions are ultimately attributable to the overexpression of RANKL, which opens up a common, practical and useful therapeutic target for diverse osteolytic conditions.

Tau: A Common Denominator and Therapeutic Target for Neurodegenerative Disorders.

There is compelling evidence that a number of neurodegenerative diseases share common pathogenic mechanisms. Better understanding these mechanisms will allow us to develop new therapeutic strategies. This commentary follows up on our recent findings that tau pathology can be found in healthy fetal tissue transplanted into the brain of patients with either Huntington or Parkinson disease. We will examine how tau appears to be shared in a number of different conditions and how its expression relates to cognitive decline and disease progression. We will further review pathogenic mechanisms and especially the relevance of the possible prion-like behavior of tau. We will conclude by discussing how all this work opens up novel therapeutic approaches to treating the cognitive impairments related to neurodegenerative diseases using a common strategy.

Role of the unfolded protein response in determining the fate of tumor cells and the promise of multi-targeted therapies.

Although there have been advances in our understanding of carcinogenesis and development of new treatments, cancer remains a common cause of death. Many regulatory pathways are incompletely understood in cancer development and progression, with a prime example being those related to the endoplasmic reticulum (ER). The pathological sequelae that arise from disruption of ER homeostasis are not well defined. The ER is an organelle that is responsible for secretory protein biosynthesis and the quality control of protein folding. The ER triggers an unfolded protein response (UPR) when misfolded proteins accumulate, and while the UPR acts to restore protein folding and ER homeostasis, this response can work as a switch to determine the death or survival of cells. The treatment of cancer with agents that target the UPR has shown promising outcomes. The UPR has wide crosstalk with other signaling pathways. Multi-targeted cancer therapies which target the intersections within signaling networks have shown synergistic tumoricidal effects. In the present review, the basic cellular and signaling pathways of the ER and UPR are introduced; then the crosstalk between the ER and other signaling pathways is summarized; and ultimately, the evidence that the UPR is a potential target for cancer therapy is discussed. Regulation of the UPR downstream signaling is a common therapeutic target for different tumor types. Tumoricidal effects achieved from modulating the UPR downstream signaling could be enhanced by phosphodiesterase 5 (PDE5) inhibitors. Largely untapped by Western medicine for cancer therapies are Chinese herbal medicines. This review explores and discusses the value of some Chinese herbal extracts as PDE5 inhibitors.

Angiogenesis biomarkers and their targeting ligands as potential targets for tumor angiogenesis.

Angiogenesis is known as one of the hallmarks in cancer which could play a key role in providing oxygen and nutrients for tumor cells. It has been shown that tumor cannot grow without sufficient development of new blood vessels. Accordingly, targeting angiogenesis, especially endothelial cells, could be considered as a common therapeutic target in tumors and more investigation on already existing biomarkers and potentially new biomarkers of endothelial cells seems to be necessary in cancer therapy. Moreover, the use of effective targeting approaches such as proteins and peptides, aptamers, and small molecules is an important step for targeting biomarkers associated with endothelial cells and angiogenesis in cancer therapy. These agents are FDA approved, or are currently under investigation in pre-clinical and clinical studies. Among various biomarkers for angiogenesis microRNAs are suitable candidates for target therapy. These molecules play key roles in tumor angiogenesis which exert their effect via targeting a variety of cellular and molecular pathways involved in tumor angiogenesis. Here, we summarize a variety of biomarkers which their expressions or their functions could change the function of endothelial cells in tumor microenvironments. Moreover, we highlighted various therapeutic agents which could target these biomarkers.

LTP and memory impairment caused by extracellular Aβ and Tau oligomers is APP-dependent.

The concurrent application of subtoxic doses of soluble oligomeric forms of human amyloid-beta (oAβ) and Tau (oTau) proteins impairs memory and its electrophysiological surrogate long-term potentiation (LTP), effects that may be mediated by intra-neuronal oligomers uptake. Intrigued by these findings, we investigated whether oAβ and oTau share a common mechanism when they impair memory and LTP in mice. We found that as already shown for oAβ, also oTau can bind to amyloid precursor protein (APP). Moreover, efficient intra-neuronal uptake of oAβ and oTau requires expression of APP. Finally, the toxic effect of both extracellular oAβ and oTau on memory and LTP is dependent upon APP since APP-KO mice were resistant to oAβ- and oTau-induced defects in spatial/associative memory and LTP. Thus, APP might serve as a common therapeutic target against Alzheimer's Disease (AD) and a host of other neurodegenerative diseases characterized by abnormal levels of Aβ and/or Tau.

Next‐generation nutritional screening

The biochemical identification of essential vitamins and minerals during the early 20th century led to major public health advances through treatment and prevention of deficiency diseases. Today, we face an epidemic of overnutrition. Chronic metabolic conditions such as obesity and diabetes are responsible for millions of deaths each year and constitute an enormous global health burden. Despite the major influence of diet on this epidemic, nutrition knowledge has not been applied as successfully as for vitamin and mineral deficiency diseases. In addition to vitamins and minerals, the foods we eat contain thousands of biologically active nutritional compounds that are managed at the cellular level by molecular networks which sense the cellular nutritional state and respond to maintain homeostasis. A key hub in these networks, and the focus of this project, is the endoplasmic reticulum (ER), a cellular organelle that is a broad sensor of nutritional and metabolic status. Impaired ER function is implicated in the development of obesity and diabetes, and improvement of ER function is a common therapeutic target that can potentially improve health in many tissues and disease states. Among its many functions, the ER is a major site for metabolism of lipids, a class of nutritional compounds that includes fatty acids and bile acids. Enzymes located on the ER membrane metabolize lipids from the diet, and also synthesize lipids de novo. While lipid synthesis at the ER has been widely studied, little is known about how the ER handles the many lipids from the diet, and how the response of the ER to dietary lipids impacts health. Without new tools to detect how cells sense and respond to nutritional compounds, we are unable to make continued progress in nutrition to reduce chronic metabolic conditions.The aim of this project is to create a novel cellular screening system to detect the effects of nutritional compounds. This project will focus on lipids, as they are rich in diversity and biology, and our lab is well‐equipped to study them. I will begin by curating a small collection of the predominant lipids in the human diet. These lipids are included in an existing collection of 688 lipids that our lab has established in collaboration with the Broad Institute for screening. In order to detect the cellular effects of lipids, I will focus on indicators of ER function. We have developed luminescent cellular reporters for real‐time monitoring of ER function in live cells. I will introduce these reporters into adipocytes, cells that manage systemic nutrient levels through storage and release of lipids. These reporter cells will be integrated into a microfluidic chip the size of a microscope slide. It will contain chambers, where we will seed cells expressing the ER reporters, and channels to flow culture medium and nutritional compounds to the cells. This system will enable high‐throughput screening of dietary lipids, continuous sampling of the culture medium for evaluation of the dynamic response of the ER, and co‐culture of related cell types, such as adipocytes and macrophages, to model cellular interactions.Support or Funding InformationWe acknowledge the generous support of the Sabri Ülker Food Research Foundation, Sabri Ülker Center, and Harvard Training Program in Nutritional Metabolism T32 training grant (4T32HD052961‐10).

PI3K Catalytic Isoform Alteration Promotes the LIMK1-related Metastasis Through the PAK1 or ROCK1/2 Activation in Cigarette Smoke-exposed Ovarian Cancer Cells

To investigate the molecular mechanisms by which long-term exposure to cigarette smoke extract (CSE) contributes to ovarian cancer metastasis. Western blot analysis for diverse p110 isoforms of phosphoinositide 3-kinase (PI3K)-related signaling pathway and epithelial-mesenchymal transition (EMT) markers was performed to analyze the underlying mechanisms. Migratory activity of CSE-exposed ovarian cancer cells was determined by transendothelial migration and invasion assay. After exposure to CSE for four weeks, CaOV3 (primary) and SKOV3 (metastatic) ovarian cancer cells showed enhanced mesenchymal characteristics and produced EMT-related cytokines [intwerleukin-8 (IL-8), vascular endothelial growth factor (VEGF) and transforming growth factor-beta 1 (TGF-β1)]. CSE exposure activated the Src-p110δ-p21 protein-activated kinase 1 (PAK1) in CaOV3 cells and the Lyn-p110β-Rho-associated kinases 1/2 (ROCK1/2) in SKOV3 cells, which led to the stimulation of LIM kinase 1 (LIMK1) phosphorylation and TGF-β1 release. LIMK1 knockdown efficiently blocked the migratory activity and suppressed the mesenchymal phenotypes of CSE-treated ovarian cancer cells. Reactive oxygen species (ROS) initiated the CSE-mediated EMT processes in ovarian cancer cells. Characterization of the p110 isotypes of PI3K is critical for regulating cancer metastasis; LIMK1 could be a common therapeutic target of ovarian cancer metastasis.

NR2F2 inhibits Smad7 expression and promotes TGF-β-dependent epithelial-mesenchymal transition of CRC via transactivation of miR-21

Metastasis is one of the most decisive factors influencing CRC patient prognosis and current studies suggest that a molecular mechanism known as EMT broadly regulates cancer metastasis. NR2F2 is a key molecule in the development of CRC, but the roles and underlying mechanisms of NR2F2 in TGF-β induced EMT in CRC remain largely unknown. In the current study, we were interested to examine the role of NR2F2 in the TGF-β-induced EMT in CRC. Here, we found NR2F2 was upregulated in CRC cells and promotes TGF-β-induced EMT in CRC. Using comparative miRNA profiling TGF-β pre-treated CRC cells in which NR2F2 had been knocked down with that of control cells, we identified miR-21 as a commonly downregulated miRNA in HT29 cells treated with TGF-β and NR2F2 siRNA, and its downregulation inhibiting migration and invasion of CRC cells. Moreover, we found NR2F2 could transcriptional activated miR-21 expression by binding to miR-21 promoter in HT29 by ChIP and luciferase assay. In the last, our data demonstrated that Smad7 was the direct target of miR-21 in CRC cells. Thus, NR2F2 could promote TGF-β-induced EMT and inhibit Smad7 expression via transactivation of miR-21, and NR2F2 may be a new common therapeutic target for CRC.

Human Enterovirus 68 Interferes with the Host Cell Cycle to Facilitate Viral Production.

Enterovirus D68 (EV-D68) is an emerging pathogen that recently caused a large outbreak of severe respiratory disease in the United States and other countries. Little is known about the relationship between EV-D68 virus and host cells. In this study, we assessed the effect of the host cell cycle on EV-D68 viral production, as well as the ability of EV-D68 to manipulate host cell cycle progression. The results suggest that synchronization in G0/G1 phase, but not S phase, promotes viral production, while synchronization in G2/M inhibits viral production. Both an early EV-D68 isolate and currently circulating strains of EV-D68 can manipulate the host cell cycle to arrest cells in the G0/G1 phase, thus providing favorable conditions for virus production. Cell cycle regulation by EV-D68 was associated with corresponding effects on the expression of cyclins and CDKs, which were observed at the level of the protein and/or mRNA. Furthermore, the viral non-structural protein 3D of EV-D68 prevents progression from G0/G1 to S. Interestingly, another member of the Picornaviridae family, EV-A71, differs from EV-D68 in that G0/G1 synchronization inhibits, rather than promotes, EV-A71 viral replication. However, these viruses are similar in that G2/M synchronization inhibits the production and activity of both viruses, which is suggestive of a common therapeutic target for both types of enterovirus. These results further clarify the pathogenic mechanisms of enteroviruses and provide a potential strategy for the treatment and prevention of EV-D68-related disease.