Role In Crosstalk Research Articles

Tumor-derived exosomes: Key players in non-small cell lung cancer metastasis and their implication for targeted therapy.

Exosomes represent extracellular vesicles of endocytic origin ranging from 30 to 100 nm that are released by most of eukaryotic cells and can be found in body fluids. These vesicles in carrying DNA, RNA, microRNA (miRNA), Long noncoding RNA, proteins, and lipids serve as intercellular communicators. Due to their role in crosstalk between tumor cells and mesenchymal stroma cells, they are vital for tumor growth, progression, and anticancer drug resistance. Lung cancer is a global leading cause of cancer-related deaths with 5-year survival rates of about 7% in patients with distant metastasis. Although the implementation of targeted therapy has improved the clinical outcome of nonsmall cell lung cancer, drug resistance remains a major obstacle. Lung tumor-derived exosomes (TDEs) conveying molecular information from tumor cells to their neighbor cells or cells at distant sites of the body activate the tumor microenvironment (TME) and facilitate tumor metastasis. Exosomal miRNAs are also considered as noninvasive biomarkers for early diagnosis of lung cancer. This review summarizes the influence of lung TDEs on the TME and metastasis. Their involvement in targeted therapy resistance and potential clinical applications are discussed. Additionally, challenges encountered in the development of exosome-based therapeutic strategies are addressed.

Analysis of Differentially Expressed Genes That Aggravate Metabolic Diseases in Depression.

Depression is considered the second leading cause of the global health burden after cancer. It is recognized as the most common physiological disorder. It affects about 350 million people worldwide to a serious degree. The onset of depression, inadequate food intake, abnormal glycemic control and cognitive impairment have strong associations with various metabolic disorders which are mediated through alterations in diet and physical activities. The regulatory key factors among metabolic diseases and depression are poorly understood. To understand the molecular mechanisms of the dysregulation of genes affected in depressive disorder, we employed an analytical, quantitative framework for depression and related metabolic diseases. In this study, we examined datasets containing patients with depression, obesity, diabetes and NASH. After normalizing batch effects to minimize the heterogeneity of all the datasets, we found differentially expressed genes (DEGs) common to all the datasets. We identified significantly associated enrichment pathways, ontology pathways, protein–protein cluster networks and gene–disease associations among the co-expressed genes co-expressed in depression and the metabolic disorders. Our study suggested potentially active signaling pathways and co-expressed gene sets which may play key roles in crosstalk between metabolic diseases and depression.

DHFR silence alleviated the development of liver fibrosis by affecting the crosstalk between hepatic stellate cells and macrophages.

Liver fibrogenesis is a dynamic cellular and tissue process which has the potential to progress into cirrhosis of even liver cancer and liver failure. The activation of hepatic stellate cells (HSCs) is the central event underlying liver fibrosis. Besides, hepatic macrophages have been proposed as potential targets in combatting fibrosis. As for the relationship between HSCs and hepatic macrophages in liver fibrosis, it is generally considered that macrophages promoted liver fibrosis via activating HSCs. However, whether activated HSCs could in turn affect macrophage polarization has rarely been studied. In this study, mRNAs with significant differences were explored using exosomal RNA‐sequencing of activated Lx‐2 cells and normal RNA‐sequencing of DHFR loss‐of‐function Lx‐2 cell models. Cell functional experiments in both Lx‐2 cells and macrophages animal model experiments were performed. The results basically confirmed exosomes secreted from activated HSCs could promote M1 polarization of macrophages further. Exosome harbouring DHFR played an important role in this process. DHFR silence in HSCs could decrease Lx‐2 activation and M1 polarization of M0 macrophages and then alleviate the development of liver fibrosis both in vitro and vivo. Our work brought a new insight that exosomal DHFR derived from HSCs had a crucial role in crosstalk between HSCs activation and macrophage polarization, which may be a potential therapeutic target in liver fibrosis.

Roles of Crosstalk between Astrocytes and Microglia in Triggering Neuroinflammation and Brain Edema Formation in 1,2-Dichloroethane-Intoxicated Mice.

We have previously reported that the activation of astrocytes and microglia may lead to the overproduction of proinflammatory mediators, which could induce neuroinflammation and cause brain edema in 1,2-dichloroethane (1,2-DCE)-intoxicated mice. In this research, we further hypothesized that astrocyte–microglia crosstalk might trigger neuroinflammation and contribute to brain edema in 1,2-DCE-intoxicated mice. The present research revealed, for the first time, that subacute intoxication with 1,2-DCE might provoke the proinflammatory polarization of microglia, and pretreatment with minocycline, a specific inhibitor of microglial activation, may attenuate the enhanced protein levels of ionized calcium-binding adapter molecule1 (Iba-1), cluster of differentiation 11b (CD11b), glial fibrillary acidic protein (GFAP), soluble calcium-binding protein 100B (S100B), tumor necrosis factor α (TNF-α), interleukin 6 (IL-6), inducible nitric oxide synthase (iNOS), vascular cell adhesion molecule-1 (VCAM-1), intercellular adhesion molecule-1 (ICAM-1), matrix metalloproteinase-9 (MMP-9), Toll-like receptor 4 (TLR4), MyD88, and p-p65, and ameliorate the suppressed protein expression levels of occludin and claudin 5; we also observed changes in water content and made pathological observations on edema in the brains of 1,2-DCE-intoxicated mice. Moreover, pretreatment with fluorocitrate, an inhibitor of reactive astrocytes, could also reverse the alteration in protein expression levels of GFAP, S100B, Iba-1, CD11b, TNF-α, IL-6, iNOS, VCAM-1, ICAM-1, MMP-9, occludin, and claudin 5 in the brain of 1,2-DCE intoxicated mice. Furthermore, pretreatment with melatonin, a well-known anti-inflammatory drug, could also attenuate the above-mentioned changes in the brains of 1,2-DCE-intoxicated mice. Altogether, the findings from this research indicated that microglial activation might play an important role in triggering neuroinflammation, and hence may contribute to brain edema formation; additionally, the findings suggested that molecular crosstalk between reactive astrocytes and activated microglia may amplify the neuroinflammatory reaction, which could induce secondary brain injury in 1,2-DCE-intoxicated mice.

Primary root and root hair development regulation by OsAUX4 and its participation in the phosphate starvation response.

Among the five members of AUX1/LAX genes coding for auxin carriers in rice, only OsAUX1 and OsAUX3 have been reported. To understand the function of the other AUX1/LAX genes, two independent alleles of osaux4 mutants, osaux4-1 and osaux4-2, were constructed using the CRISPR/Cas9 editing system. Homozygous osaux4-1 or osaux4-2 exhibited shorter primary root (PR) and longer root hair (RH) compared to the wild-type Dongjin (WT/DJ), and lost response to indoleacetic acid (IAA) treatment. OsAUX4 is intensively expressed in roots and localized on the plasma membrane, suggesting that OsAUX4 might function in the regulation of root development. The decreased meristem cell division activity and the downregulated expression of cell cycle genes in root apices of osaux4 mutants supported the hypothesis that OsAUX4 positively regulates PR elongation. OsAUX4 is expressed in RH, and osaux4 mutants showing longer RH compared to WT/DJ implies that OsAUX4 negatively regulates RH development. Furthermore, osaux4 mutants are insensitive to Pi starvation (-Pi) and OsAUX4 effects on the -Pi response is associated with altered expression levels of Pi starvation-regulated genes, and auxin distribution/contents. This study revealed that OsAUX4 not only regulates PR and RH development but also plays a regulatory role in crosstalk between auxin and -Pi signaling.

Heterologous expression of rice annexin OsANN5 potentiates abiotic stress tolerance in transgenic tobacco through ROS amelioration

An earlier investigation showed that annexin OsANN5 of rice was expressed to high levels in various stress treatments. In the present study, we have investigated the molecular mechanism underlying stress responses of OsANN5 through heterologous expression in transgenic tobacco and E. coli. E. coli cells expressing OsANN5 showed improved growth under high salt and heat stress treatments. Transgenic tobacco plants overexpressing OsANN5 exhibited tolerance to salinity, drought and osmotic stress during seed germination and post-germinative stages. The transgenic plants showed increased accumulation of proline, reduced chlorosis and membrane damage as compared to the wild type plants. Higher expression of OsANN5 also resulted in efficient scavenging of reactive oxygen species through the modulation of anti-oxidant enzymes, superoxide dismutase and catalase under stress treatments. OsANN5 exhibited calcium binding activity and under salt stress, relocated from the peripheral regions to cytosol. This suggests that OsANN5 has multiple functions in rice growth and stress tolerance. Promoter analysis of OsANN5 revealed the presence of several cis-acting elements that are well known to be involved in hormonal and stress response regulation. The expression patterns of OsANN5 in the presence of ABA synthesis inhibitor, fluoridone and salinity stress revealed that upregulation of OsANN5 transcripts is regulated by both ABA-dependent and independent pathways. This indicates OsANN5 may play a role in cross-talk between ABA-dependent and independent pathways during the abiotic stress response.

Exact results for queuing models of stochastic transcription with memory and crosstalk.

Gene transcription is a complex multistep biochemical process, which can create memory between individual reaction events. On the other hand, many inducible genes, when activated by external cues, are often coregulated by several competitive pathways with crosstalk. This raises an unexplored question: how do molecular memory and crosstalk together affect gene expressions? To address this question, we introduce a queuing model of stochastic transcription, where two crossing signaling pathways are used to direct gene activation in response to external signals and memory functions to model multistep reaction processes involved in transcription. We first establish, based on the total probability principle, the chemical master equation for this queuing model, and then we derive, based on the binomial moment approach, exact expressions for statistical quantities (including distributions) of mRNA, which provide insights into the roles of crosstalk and memory in controlling the mRNA level and noise. We find that molecular memory of gene activation decreases the mRNA level but increases the mRNA noise, and double activation pathways always reduce the mRNA noise in contrast to a single pathway. In addition, we find that molecular memory can make the mRNA bimodality disappear.

Comprehensive molecular dissection of TIFY Transcription factors reveal their dynamic responses to biotic and abiotic stress in wheat (Triticum aestivum L.)

The plant specific TIFY (previously known as ZIM) transcription factor (TF) family plays crucial roles in cross talk between Jasmonic Acid and other phytohormones like gibberellins, salicylic acid, abscisic acid, auxin, and ethylene signaling pathways. Wheat yield is severely affected by rust diseases and many abiotic stresses, where different phytohormone signaling pathways are involved. TIFYs have been studied in many plants yet reports describing their molecular structure and function in wheat are lacking. In the present study, we have identified 23 novel TIFY genes in wheat genome using in silico approaches. The identified proteins were characterized based on their conserved domains and phylogenetically classified into nine subfamilies. Chromosomal localization of the identified TIFY genes showed arbitrary distribution. Forty cis-acting elements including phytohormone, stress and light receptive elements were detected in the upstream regions of TIFY genes. Seventeen wheat microRNAs targeted the identified wheat TIFY genes. Gene ontological studies revealed their major contribution in defense response and phytohormone signaling. Secondary structure of TIFY proteins displayed the characteristic alpha–alpha–beta fold. Synteny analyses indicated all wheat TIFY genes had orthologous sequences in sorghum, rice, maize, barley and Brachypodium indicating presence of similar TIFY domains in monocot plants. Six TIFY genes had been cloned from wheat genomic and cDNA. Sequence characterization revealed similar characteristics as the in silico identified novel TIFY genes. Tertiary structures predicted the active sites in these proteins to play critical roles in DNA binding. Expression profiling of TIFY genes showed their contribution during incompatible and compatible leaf rust infestation. TIFY genes were also highly expressed during the initial hours of phytohormone induced stress. This study furnishes fundamental information on characterization and putative functions of TIFY genes in wheat.

Role of crosstalk between endothelial cells and smooth muscle cells in vascular calcification in chronic kidney disease.

Chronic kidney disease (CKD) is a severe health problem worldwide, and vascular calcification (VC) contributes substantially to the cardiovascular morbidity and high mortality of CKD. CKD is often accompanied by a variety of pathophysiological states, such as inflammation, oxidative stress, hyperglycaemia, hyperparathyroidism and haemodynamic derangement, that can cause injuries to smooth muscle cells (SMCs) and endothelial cells (ECs) to promote VC. Similar to SMCs, whose role has been widely explored in VC, ECs may contribute to VC via osteochondral transdifferentiation, apoptosis, etc. In addition, given their location in the innermost layer of the blood vessel lumen and preferential reception of various pro‐calcification stimuli, ECs can pass messages to vascular wall cells and communicate with them. Crosstalk between ECs and SMCs via cytokines through a paracrine mechanism, extracellular vesicles, miRNAs and myoendothelial gap junctions also plays a role in VC. In this review, we emphasize the role of intercellular crosstalk between ECs and SMCs in VC associated with CKD.

Tumor-derived exosomal circFARSA mediates M2 macrophage polarization via the PTEN/PI3K/AKT pathway to promote non-small cell lung cancer metastasis

BackgroundExosomes in the tumor microenvironment (TME) facilitate tumor progression by enabling inter-cellular communication. Tumor cell-derived exosomes can polarize tumor-associated macrophages (TAMs) to an immunosuppressive M2 phenotype. The aim of this study was to determine the role of exosomal circFARSA in non-small cell lung cancer (NSCLC) and elucidate the underlying mechanisms. MethodsIn situ circFARSA expression in NSCLC tissues was analyzed using qRT-PCR. The in vitro migration of NSCLC cells was evaluated using a transwell assay or through indirect co-culture with M2 macrophages, as appropriate. Immunoprecipitation (IP), western blotting, RNA binding protein immunoprecipitation (RIP), and RNA pull down assays were conducted for mechanistic studies. ResultsCircFARSA was significantly upregulated in NSCLC tissues, and the ectopic overexpression of circFARSA enhanced NSCLC cell metastasis. Furthermore, NSCLC cell-derived exosomal circFARSA polarized the macrophages to a M2 phenotype. The NSCLC cells co-cultured with macrophages transfected with circFARSA or pre-treated with exosomal circFARSA showed enhanced EMT and metastasis. Mechanistically, exosomal circFARSA induced M2 polarization via PTEN ubiquitination and degradation, which further activated the PI3K/AKT signaling pathway. In addition, eIF4A3 promoted circRNA biogenesis and cyclization by binding to its flanking sequences. ConclusionExosomal circFARSA plays a crucial role in cross-talk between macrophages and NSCLC cells through the PTEN/PI3K/AKT signaling pathway, and is a promising diagnostic/prognostic biomarker for NSCLC.

Genome-wide identification and expression analysis of Arabidopsis GRAM-domain containing gene family in response to abiotic stresses and PGPR treatment

Characterization of stress-responsive genes is important to understand the genomics perspective of stress tolerance. In this purview, several gene-families are being identified and characterized in the model and non-model plant species, which has greatly enhanced the knowledge of molecular intricacies associated with stress tolerance. One such gene family is the GRAM-domain containing which have been found to be upregulated in response to plant growth-promoting rhizobacteria (PGPR) treatment followed by salinity stress. Thus, we aimed at understanding the involvement of GRAM domain-containing proteins in abiotic stress response under the influence of rhizobacteria in Arabidopsis thaliana. The study identified fourteen AtGRAM genes in A. thaliana. Further, comprehensive analyses of domain family including phylogenetic studies, domain architecture, gene structure and genomic composition analysis, promoter analysis, homology modelling, and duplication and divergence rates estimation was performed. RNA-Seq derived expression profiling of AtGRAM genes using GENVESTIGATOR in different stresses, developmental stages and hormonal treatments was performed, followed by qRT-PCR analysis under abiotic stresses in response to PGPR. Altogether, the study provided insights into the structure, organization, and evolutionary properties of AtGRAM gene family. Modulation in expression pattern in response to stresses influenced by PGPR-treatment suggests its multifaceted role in cross-talk among abiotic stresses and phytohormones. Further functional characterization of the selected candidate genes would enable understanding of the precise roles of GRAM-genes underlying stress tolerance.

Plant sugars: Homeostasis and transport under abiotic stress in plants.

The sessile nature of plants' life is endowed with a highly evolved defense system to adapt and survive under environmental extremes. To combat such stresses, plants have developed complex and well-coordinated molecular and metabolic networks encompassing genes, metabolites, and acclimation responses. These modulate growth, photosynthesis, osmotic maintenance, and carbohydrate homeostasis. Under a given stress condition, sugars act as key players in stress perception, signaling, and are a regulatory hub for stress-mediated gene expression ensuring responses of osmotic adjustment, scavenging of reactive oxygen species, and maintaining the cellular energy status through carbon partitioning. Several sugar transporters are known to regulate carbohydrate partitioning and key signal transduction steps involved in the perception of biotic and abiotic stresses. Sugar transporters such as SUGARS WILL EVENTUALLY BE EXPORTED TRANSPORTER (SWEETs), SUCROSE TRANSPORTERS (SUTs), and MONOSACCHARIDE TRANSPORTERS (MSTs) are involved in sugar loading and unloading as well as long-distance transport (source to sink) besides orchestrating oxidative and osmotic stress tolerance. It is thus necessary to understand the structure-function relationship of these sugar transporters to fine-tune the abiotic stress-modulated responses. Advances in genomics have unraveled many sugars signaling components playing a key role in cross-talk in abiotic stress pathways. An integrated omics approach may aid in the identification and characterization of sugar transporters that could become targets for developing stress tolerance plants to mitigate climate change effects and improve crop yield. In this review, we have presented an up-to-date analysis of the sugar homeostasis under abiotic stresses as well as describe the structure and functions of sugar transporters under abiotic stresses.

An OsNAM gene plays important role in root rhizobacteria interaction in transgenic Arabidopsis through abiotic stress and phytohormone crosstalk.

Overexpression of Bacillus amyloliquefaciens SN13-responsive OsNAM gene in Arabidopsis reveals its important role in beneficial plant and plant growth promoting rhizobacteria interaction by conferring stress tolerance and phytohormone modulation. Salinity is one of the major constraints that affect crop development and yield. Plants respond and adapt to salt stress via complex mechanisms that involve morpho-physiological, biochemical, and molecular changes. The expression of numerous genes is known to alter during various abiotic stresses and impart stress tolerance. Recently, some known rhizospheric microbes have also been used to mitigate the effects of abiotic stresses; however, the molecular basis of such interactions remains elusive. Therefore, the present investigation was aimed to elucidate the plant growth-promoting rhizobacteria (PGPR; Bacillus amyloliquefaciens-SN13) -induced crosstalk among salinity and phytohormones in OsNAM-overexpressed Arabidopsis plants. Transgenic plants showed increased germination percentage compared to wild-type (WT) seeds under 100mM of NaCl. Phenotypic data showed increased root length, rosette diameter, leaf size, and biomass in transgenics than WT plants. Transgenic plants can also better maintain membrane integrity and osmolyte concentration under salinity as compared to WT. Further, gene expression analysis of AP2/ERF, GST, ERD4, and ARF2 genes showed differential expression and their positive modulation in transgenic Arabidopsis exposed to salt stress in the presence of SN13 as compared to uninoculated WT. Modulation in IAA, ABA, and GA content in inoculated plants showed the more pronounced positive effects of SN13 on transgenic plants that supported our findings on Arabidopsis-SN13 interaction. Overall, the study concludes that SN13 positively modulated expression of stress-responsive genes under salinity and alter phytohormones levels in OsNAM-overexpressed plants suggesting its extensive role in cross-talk among salinity and phytohormones in response to PGPR.

Host and Pathogen Communication in the Respiratory Tract: Mechanisms and Models of a Complex Signaling Microenvironment.

Chronic lung diseases are a leading cause of morbidity and mortality across the globe, encompassing a diverse range of conditions from infections with pathogenic microorganisms to underlying genetic disorders. The respiratory tract represents an active interface with the external environment having the primary immune function of resisting pathogen intrusion and maintaining homeostasis in response to the myriad of stimuli encountered within its microenvironment. To perform these vital functions and prevent lung disorders, a chemical and biological cross-talk occurs in the complex milieu of the lung that mediates and regulates the numerous cellular processes contributing to lung health. In this review, we will focus on the role of cross-talk in chronic lung infections, and discuss how different cell types and signaling pathways contribute to the chronicity of infection(s) and prevent effective immune clearance of pathogens. In the lung microenvironment, pathogens have developed the capacity to evade mucosal immunity using different mechanisms or virulence factors, leading to colonization and infection of the host; such mechanisms include the release of soluble and volatile factors, as well as contact dependent (juxtracrine) interactions. We explore the diverse modes of communication between the host and pathogen in the lung tissue milieu in the context of chronic lung infections. Lastly, we review current methods and approaches used to model and study these host-pathogen interactions in vitro, and the role of these technological platforms in advancing our knowledge about chronic lung diseases.

Crosstalk between cardiomyocytes and noncardiomyocytes is essential to prevent cardiomyocyte apoptosis induced by proteasome inhibition

Heart is a multi-cellular organ made up of various cell types interacting with each other. Cardiomyocytes may benefit or suffer from crosstalk with noncardiomyocytes in response to diverse kinds of cardiac stresses. Proteasome dysfunction is a common cardiac stress which causes cardiac proteotoxicity and contributes to cardiac diseases such as heart failure and myocardial infarction. The role of crosstalk between cardiomyocytes and noncardiomyocytes in defense of cardiac proteotoxicity remains unknown. Here, we report a cardiomyocyte-specific survival upon proteasome inhibition in a heterogeneous culture consisting of cardiomyocytes and other three major cardiac cell types. Conversely, cardiomyocyte apoptosis is remarkably induced by proteasome inhibition in a homogeneous culture consisting of a majority of cardiomyocytes, demonstrating an indispensable role of noncardiomyocytes in the prevention of cardiomyocyte apoptosis resulting from proteasome inhibition. We further show that cardiomyocytes express brain natriuretic peptide (BNP) as an extracellular molecule in response to proteasome inhibition. Blockade of BNP receptor on noncardiomyocytes significantly exacerbated the cardiomyocyte apoptosis, indicating a paracrine function of cardiomyocyte-released extracellular BNP in activation of a protective feedback from noncardiomyocytes. Finally, we demonstrate that proteasome inhibition-activated transcriptional up-regulation of BNP in cardiomyocytes was associated with the dissociation of repressor element 1 silencing transcription factor (REST)/ histone deacetylase 1 (HDAC1) repressor complex from BNP gene promoter. Consistently, the induction of BNP could be further augmented by the treatment of HDAC inhibitors. We conclude that the crosstalk between cardiomyocytes and noncardiomyocytes plays a crucial role in the protection of cardiomyocytes from proteotoxicity stress, and identify cardiomyocyte-released BNP as a novel paracrine signaling molecule mediating this crosstalk. These findings provide new insights into the key regulators and cardioprotective mechanism in proteasome dysfunction-related cardiac diseases.

Abstract 3966: The procancer effects of obesity can be reversed by moderate weight loss or an anti-inflammatory drug in a mouse model of colon cancer

Abstract Purpose: Obesity is associated with an increased risk of colon cancer. Our current study examines whether moderate weight loss or treatment with the non-steroidal anti-inflammatory drug sulindac suppresses the tumor-promoting effects of obesity in a mouse model of colon cancer. Methods: Male FVB mice were treated with azoxymethane (10 mg/kg i.p.) for 5 weeks, then randomized to a control (10% kcal from fat) or diet-induced obesity (DIO, 60% kcal from fat) diet. After 15 weeks, there was an interim sacrifice of 5 mice/group. The DIO mice were then further randomized to remain on DIO or switch to control diet to induce weight loss and become formerly obese mice (FOB), and within each diet group (control, DIO, and FOB), half the mice were randomized to start sulindac treatment (140 ppm in the diet). Eight weeks later, all mice were euthanized. Results: The DIO mice, compared to controls, had significantly greater body weight and body fat (P<0.05), while FOB mice had intermediate levels of adiposity. Sulindac did not affect adiposity in any diet group. At the interim timepoint, DIO mice had 10-fold greater tumor multiplicity relative to control mice (P=0.07). At study endpoint, DIO mice had greater tumor multiplicity compared to both control (P<0.05) and FOB (P<0.01) mice, which did not significantly differ from each other. Sulindac reduced tumor multiplicity in both control (P<0.05) and DIO (P<0.0001) mice, but not FOB mice. Serum levels of several inflammation-related proteins, including interleukin 6, chemokine (C-X-C motif) ligand 1, monocyte chemoattractant protein 1, and vascular endothelial growth factor, were elevated in DIO mice versus control (P<0.05) and DIO+sulindac (P<0.01) mice, but not in comparison to FOB mice. Gene expression in paired colon tumor and mesenteric adipose tissue samples was assessed by microarray. Ingenuity pathway analysis (IPA) of the significant (P<0.05) differentially expressed tumor genes indicated that both weight loss and sulindac reduced signaling related to matrix metalloproteinases (MMPs) and inflammation. In the visceral adipose tissue, IPA demonstrated that weight loss reduced signaling related to B cell receptors and glucose/fatty acid metabolism while sulindac decreased MMP, prostaglandin, and PPAR signaling. Additional analyses to explore the potential role of cross-talk between these two tissues are being performed, and key findings will be validated in the tissues at the protein level and via mechanistic cell culture experiments. Conclusions: Both moderate weight loss and sulindac treatment completely reverse the effects of chronic obesity on colon tumorigenesis, the latter independent of any change in adiposity. Our findings suggest that an investigation regarding the effects of NSAID treatment on colon cancer risk and/or progression in obese patients is warranted, particularly for those unable to achieve moderate weight loss. Citation Format: Laura W. Bowers, Arunima Punjala, Alison Q. Jeffries, Stephanie A. Montgomery, Andrew J. Dannenberg, Stephen D. Hursting. The procancer effects of obesity can be reversed by moderate weight loss or an anti-inflammatory drug in a mouse model of colon cancer [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 3966.

Abstract IA09: The crosstalk between Hippo-YAP/TAZ and PTEN-AKT signaling in liver metabolic dysregulation and tumorigenesis

Abstract Several in vitro studies have suggested that Hippo-YAP/TAZ signaling regulates the AKT pathway components PI3K and PTEN. Increased YAP expression in human liver tumors is associated with high levels of phosphorylated AKT. This suggests that crosstalk between the Hippo and AKT pathways may be important in the maintenance of functional liver homeostasis. The nature of such crosstalk has thus far remained unclear. Here, we investigated the possible role of crosstalk between Hippo-YAP/TAZ and PTEN-AKT pathways in the liver. Deletion of both Pten and Sav1 in the liver (DKO) accelerates the development of nonalcoholic fatty liver disease (NAFLD) and liver cancer in mice through excessive activation of AKT. At the molecular level, activation of YAP and TAZ amplifies AKT signaling through direct upregulation of IRS2 expression. Deletion of YAP/TAZ or activation of Hippo attenuated development of fatty liver in these DKO mice by downregulating IRS2. Notably, increased YAP/TAZ expression was also associated with high level of IRS2-pAKT in the patient. Moreover, treatment with the AKT inhibitor MK-2206 attenuated NAFLD development and tumorigenesis in DKO mice. Our findings suggest that crosstalk between Hippo and AKT pathways at the level of YAP/TAZ-IRS2 contributes to the development and progression of NAFLD to liver cancer, and they therefore provide a basis for the development of new therapeutic interventions. Citation Format: Sun-Hye Jeong, Dae-Sik Lim. The crosstalk between Hippo-YAP/TAZ and PTEN-AKT signaling in liver metabolic dysregulation and tumorigenesis [abstract]. In: Proceedings of the AACR Special Conference on the Hippo Pathway: Signaling, Cancer, and Beyond; 2019 May 8-11; San Diego, CA. Philadelphia (PA): AACR; Mol Cancer Res 2020;18(8_Suppl):Abstract nr IA09.

Role of crosstalk between STAT3 and mTOR signaling in driving sensitivity to chemotherapy in osteosarcoma cell lines.

Osteosarcoma (OS) is a malignant bone neoplasm, mostly occurring in pediatric patients. OS is characterized by a highly aggressive and metastatically active tumor. Chemotherapy followed by surgical excision is the treatment of choice but is often associated with both chemoresistance and relapse. Hence, it is important to develop further understanding of OS pathogenesis and identify potential therapeutic targets. Both the signal transducer and activator of transcription 3 (STAT3) and mammalian target of rapamycin (mTOR) have been implicated in OS pathogenesis. Crosstalk between mTOR and STAT3 signaling has been shown to regulate hypoxia-induced angiogenesis in other diseases. In this study, we determined using OS cell lines if there is a crosstalk between these two pathways and how that impacts sensitivity to treatment with Rapamycin. OS cell lines exhibited differential sensitivity to mTOR inhibitor Rapamycin. Evaluation of phosphorylated STAT3 showed that in Rapamycin-sensitive 143B cells, the inhibitor decreased phosphorylation of STAT3 at Y705, but not at S727 whereas, in Rapamycin-resistant U2OS cells, the inhibitor decreased S727 phosphorylation but not Y705. However, knockdown of STAT3 in U2OS cells made them sensitive to Rapamycin. Immunofluorescence (IF) analysis showed that mTOR is constitutively activated in the 143B cells but is suppressed in the U2OS cells, indicating that this might be their reason for being resistant to Rapamycin. Both cell lines were sensitive to treatment with the STAT3 inhibitor Napabucasin (NP). Treatment with NP inhibited STAT3 activation at Y705 and additionally inhibited mTOR activation, indicating crosstalk between STAT3 and mTOR signaling pathways. Rapamycin could effectively prevent lung metastasis in an orthotropic OS mice model using 143B cells. However, Rapamycin could not inhibit lung metastasis in mice injected with U2OS cells. The STAT3 inhibitor NP attenuated lung metastasis with the U2OS cells. Our results thus established yet undefined crosstalk of STAT3 and mTOR signaling pathways in OS and highlight the possibility of using mTOR inhibitors for treatment in patients with OS.

Jasmonates: biosynthesis, perception and signal transduction.

Jasmonates (JAs) are physiologically important molecules involved in a wide range of plant responses from growth, flowering, senescence to defence against abiotic and biotic stress. They are rapidly synthesised from α-linolenic acid (ALA; C18:3 ∆9,12,15) by a process of oxidation, cyclisation and acyl chain shortening involving co-operation between the chloroplast and peroxisome. The active form of JA is the isoleucine conjugate, JA-isoleucine (JA-Ile), which is synthesised in the cytoplasm. Other active metabolites of JA include the airborne signalling molecules, methyl JA (Me-JA) and cis-jasmone (CJ), which act as inter-plant signalling molecules activating defensive genes encoding proteins and secondary compounds such as anthocyanins and alkaloids. One of the key defensive metabolites in many plants is a protease inhibitor that inactivates the protein digestive capabilities of insects, thereby, reducing their growth. The receptor for JA-Ile is a ubiquitin ligase termed as SCFCoi1 that targets the repressor protein JA Zim domain (JAZ) for degradation in the 26S proteasome. Removal of JAZ allows other transcription factors (TFs) to activate the JA response. The levels of JA-Ile are controlled through catabolism by hydroxylating enzymes of the cytochrome P450 (CYP) family. The JAZ proteins act as metabolic hubs and play key roles in cross-talk with other phytohormone signalling pathways in co-ordinating genome-wide responses. Specific subsets of JAZ proteins are involved in regulating different response outcomes such as growth inhibition versus biotic stress responses. Understanding the molecular circuits that control plant responses to pests and pathogens is a necessary pre-requisite to engineering plants with enhanced resilience to biotic challenges for improved agricultural yields.

The role of Wnt signaling pathway in osteoarthritis via the dual-targeted regulation of cartilage and subchondral bone

To summarize the active changes of Wnt signaling pathway in osteoarthritis (OA) as well as the influence and mechanism of dual-targeted regulation on cartilage and subchondral bone and the role of crosstalk between them on OA process. The relevant literature concerning the articular cartilage, subchondral bone, and crosstalk between them in OA and non-OA states by Wnt signaling pathway in vivo and vitro experimental studies and clinical studies in recent years was reviewed, and the mechanism was analyzed and summarized. Wnt signaling can regulate the differentiation and function of chondrocytes and osteoblasts through the classic β-catenin-dependent or non-classical β-catenin-independent Wnt signaling pathway and its cross-linking with other signaling pathways, thereby affecting the cartilage and bone metabolism. Moreover, Wnt signaling pathway can activate the downstream protein Wnt1-inducible-signaling pathway protein 1 to regulate the progress of OA and it also can be established gap junctions between different cells in cartilage and subchondral bone to communicate molecules directly to regulate OA occurrence and development. Intra-articular injection of Wnt signaling inhibitor SM04690 can inhibit the progress of OA, and overexpression of Wnt signaling pathway inhibitor Dickkopf in osteoblasts can antagonize the role of vascular endothelial growth factor work on chondrocytes and inhibit the catabolism of its matrix. The regulation of metabolism and function of cartilage and subchondral bone and crosstalk between them is through interactions among Wnt signaling pathway and molecules of other signaling. Therefore, it plays an vital role in the occurrence and development of OA and is expected to become a new target of OA treatment through intervention and regulation of Wnt signaling pathway.