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Background Terpenoids constitute a diverse group of primary and secondary metabolites that are extensively distributed in living organisms and play key roles in growth, development, and environmental adaptation. Terpenoids are derived from two isomeric precursors that are interconverted by isopentenyl-diphosphate delta-isomerase (IDI), in both the plastids and cytoplasm of plants. The plastidial pathway supplies precursors for diterpenoids and carotenoids, whereas the cytoplasmic pathway provides precursors for sesquiterpenoids and triterpenoids. A family of terpene synthases (TPSs) produce most terpenoids such as sesquiterpenes, hemiterpenes, monoterpenes, diterpenes and sesterterpenes, which in allotetraploid peanut ( Arachis hypogaea L.) have been relatively underexplored. Results In this study, 77 AhTPS genes were identified in the peanut genome and phylogenetically classified into five subfamilies. These AhTPSs are organized in clusters across chromosomes and exhibit conserved gene structures and motifs within each subfamily. AhTPSs in the TPS-c and -e/f subfamilies, specifically copalyl diphosphate synthase (CPS) and kaurene synthase (KS), were localized to plastids through transient expression in Nicotiana benthamiana leaves. The expression of AhCPS3 was detected a significant increase in response to abscisic acid (ABA) and methyl jasmonate (MeJA), which was notably distinct from the expression patterns of other AhCPSs and AhKS . Furthermore, 12 terpenoids were identified during seed development. Module-trait correlation analysis disclosed that the expression levels of genes encoding AhCPSs (involved in diterpene biosynthesis) and phytoene synthases (AhPSYs, involved in carotenoid biosynthesis) were significantly correlated with the abundances of soyasaponins (triterpenoids) during seed development in peanut. Additionally, the gene encoding β -amyrin synthase (Ah β AS), which produces the backbone of triterpenoids, was identified in a significant module and was also induced by ABA and MeJA. Protein-protein interaction networks indicated AhCPSs, AhPSYs, and Ah β AS shared a common interacting protein, AhIDI. Conclusions These findings provide valuable insights into the potential cross-talk in terpenoid biosynthesis across different cellular compartments.

Pier Paolo Pandolfi and colleagues report that prostate-specific overexpression of ERG in transgenic mice results in no overt phenotype on its own but promotes progression of intraepithelial neoplasia to adenocarcinoma in a PTEN heterozygous background. They also find that human TMPRSS2-ERG –positive tumors are enriched for PTEN loss, suggesting that these two events cooperate in human prostate tumorigenesis. Chromosomal translocations involving the ERG locus are frequent events in human prostate cancer pathogenesis; however, the biological role of aberrant ERG expression is controversial 1 . Here we show that aberrant expression of ERG is a progression event in prostate tumorigenesis. We find that prostate cancer specimens containing the TMPRSS2-ERG rearrangement are significantly enriched for loss of the tumor suppressor PTEN. In concordance with these findings, transgenic overexpression of ERG in mouse prostate tissue promotes marked acceleration and progression of high-grade prostatic intraepithelial neoplasia (HGPIN) to prostatic adenocarcinoma in a Pten heterozygous background. In vitro overexpression of ERG promotes cell migration, a property necessary for tumorigenesis, without affecting proliferation. ADAMTS1 and CXCR4 , two candidate genes strongly associated with cell migration, were upregulated in the presence of ERG overexpression. Thus, ERG has a distinct role in prostate cancer progression and cooperates with PTEN haploinsufficiency to promote progression of HGPIN to invasive adenocarcinoma.

Soil salinization is a growing issue that limits agriculture globally. Understanding the mechanism underlying salt tolerance in halophytic grasses can provide new insights into engineering plant salinity tolerance in glycophytic plants. Seashore paspalum ( Paspalum vaginatum Sw.) is a halophytic turfgrass and genomic model system for salt tolerance research in cereals and other grasses. However, the salt tolerance mechanism of this grass largely unknown. To explore the correlation between Na + accumulation and salt tolerance in different tissues, we utilized two P. vaginatum accessions that exhibit contrasting tolerance to salinity. To accomplish this, we employed various analytical techniques including ICP-MS-based ion analysis, lipidomic profiling analysis, enzyme assays, and integrated transcriptomic and metabolomic analysis. Under high salinity, salt-tolerant P. vaginatum plants exhibited better growth and Na + uptake compared to salt-sensitive plants. Salt-tolerant plants accumulated heightened Na + accumulation in their roots, leading to increased production of root-sourced H 2 O 2 , which in turn activated the antioxidant systems. In salt-tolerant plants, metabolome profiling revealed tissue-specific metabolic changes, with increased amino acids, phenolic acids, and polyols in roots, and increased amino acids, flavonoids, and alkaloids in leaves. High salinity induced lipidome adaptation in roots, enhancing lipid metabolism in salt-tolerant plants. Moreover, through integrated analysis, the importance of amino acid metabolism in conferring salt tolerance was highlighted. This study significantly enhances our current understanding of salt-tolerant mechanisms in halophyte grass, thereby offering valuable insights for breeding and genetically engineering salt tolerance in glycophytic plants.

When the National Institutes of Health Mouse Models of Human Cancer Consortium initiated the Prostate Steering Committee 15 years ago, there were no genetically engineered mouse (GEM) models of prostate cancer (PCa). Today, a PubMed search for “prostate cancer mouse model” yields 3,200 publications and this list continues to grow. The first generation of GEM utilized the newly discovered and characterized probasin promoter driving viral oncogenes such as Simian virus 40 large T antigen to yield the LADY and TRAMP models. As the PCa research field has matured, the second generation of models has incorporated the single and multiple molecular changes observed in human disease, such as loss of PTEN and overexpression of Myc. Application of these models has revealed that mice are particularly resistant to developing invasive PCa, and once they achieve invasive disease, the PCa rarely resembles human disease. Nevertheless, these models and their application have provided vital information on human PCa progression. The aim of this review is to provide a brief primer on mouse and human prostate histology and pathology, provide descriptions of mouse models, as well as attempt to answer the age old question: Which GEM model of PCa is the best for my research question?

Cellular senescence has been recently shown to have an important role in opposing tumour initiation and promotion. Senescence induced by oncogenes or by loss of tumour suppressor genes is thought to critically depend on induction of the p19 Arf –p53 pathway. The Skp2 E3-ubiquitin ligase can act as a proto-oncogene and its aberrant overexpression is frequently observed in human cancers. Here we show that although Skp2 inactivation on its own does not induce cellular senescence, aberrant proto-oncogenic signals as well as inactivation of tumour suppressor genes do trigger a potent, tumour-suppressive senescence response in mice and cells devoid of Skp2 . Notably, Skp2 inactivation and oncogenic-stress-driven senescence neither elicit activation of the p19 Arf –p53 pathway nor DNA damage, but instead depend on Atf4, p27 and p21. We further demonstrate that genetic Skp2 inactivation evokes cellular senescence even in oncogenic conditions in which the p19 Arf –p53 response is impaired, whereas a Skp2–SCF complex inhibitor can trigger cellular senescence in p53/Pten-deficient cells and tumour regression in preclinical studies. Our findings therefore provide proof-of-principle evidence that pharmacological inhibition of Skp2 may represent a general approach for cancer prevention and therapy. Senescence kills tumours Recent studies suggest that cellular senescence — an irreversible form of cell-cycle arrest — can halt tumour growth in vitro . Hui-Kuan Lin et al . now identify a previously unknown pathway that drives senescence without the involvement of most of the known mediators of senescence. Instead, it signals via the transcription factor Atf6, and the cyclin-dependent kinase inhibitors p27 and p21. The pathway is uncovered by inactivation of the proto-oncogene Skp2 , but only in the context of oncogenic signalling. Targeting the Skp2 complex pharmacologically restricts tumorigenesis by inducing cellular senescence, suggesting that such drugs may be effective in cancer prevention and therapy. Cellular senescence — an irreversible cell-cycle arrest — has been implicated in suppressing tumour formation or growth. A new cellular signalling pathway that drives senescence has now been identified. This pathway does not involve most known mediators of senescence, and instead signals via the proteins Atf4, p27 and p21. Inactivating the proto-oncogene Skp2 in the context of oncogenic signalling can induce senescence through this new pathway, indicating that drugs that target Skp2 might be useful in cancer treatment.

Sirtuins are NAD + -dependent deacetylases that facilitate cellular stress response. They include SirT6, which protects genome stability and regulates metabolic homeostasis through gene silencing, and whose loss induces an accelerated aging phenotype directly linked to hyperactivation of the NF-κB pathway. Here we show that SirT6 binds to the H3K9me3-specific histone methyltransferase Suv39h1 and induces monoubiquitination of conserved cysteines in the PRE-SET domain of Suv39h1. Following activation of NF-κB signaling Suv39h1 is released from the IκBα locus, subsequently repressing the NF-κB pathway. We propose that SirT6 attenuates the NF-κB pathway through IκBα upregulation via cysteine monoubiquitination and chromatin eviction of Suv39h1. We suggest a mechanism based on SirT6-mediated enhancement of a negative feedback loop that restricts the NF-κB pathway. Sirtuins are involved in the regulation of responses to diverse types of cellular stress. Here the authors describe the SirT6-dependent cysteine monoubiquitination of the histone methyltransferase Suv39h1 as part of a regulatory circuit for the NF-κB pathway.

Stripe rust, caused by Puccinia striiformis f. sp. tritici , is an important disease of soft red winter wheat in the eastern region of the USA. Pioneer 26R61 has provided effective resistance to stripe rust for 10 years. To elucidate the genetic basis of the resistance, a mapping population of 178 recombinant inbred lines (RILs) was developed using single-seed descent from a cross between Pioneer 26R61 and the susceptible cultivar AGS 2000. A genetic map with 895 markers covering all 21 chromosomes was used for QTL analysis. One major QTL was detected, explaining up to 56.0% of the mean phenotypic variation, flanked by markers Xbarc124 and Xgwm359 , and assigned to the distal 22% of the short arm of wheat chromosome 2A. Evidence showed that it was different from Yr17 derived from Ae. ventricosa , the only formally named Yr gene in 2AS, and the QTL was temporarily designated as YrR61 . In addition, a minor QTL, QYr.uga - 6AS , probably conditioned high-temperature adult plant resistance. The QTL explained 6–7% of the trait variation. Preliminary test of the flanking markers for YrR61 , in two cultivars and two promising breeding lines with Pioneer 26R61 in their pedigree, indicated that YrR61 was present in these cultivars and lines, and these markers could therefore be used in marker-assisted selection.

Cell senescence and cancer Cellular senescence, a growth-arrest program that limits the lifespan of mammalian cells and prevents unlimited cell proliferation, is attracting considerable interest because of its links to tumour suppression. Using a mouse model in which the oncogene Ras is activated in the haematopoietic compartment of bone marrow, Braig et al . show that cellular senescence can block lymphoma development. Genetic inactivation of the histone methyltransferase Suv39h1 that controls senescence by ‘epigenetic’ modification of DNA-associated proteins, or a pharmacological approach that mimics loss of this enzyme, allow the formation of malignant lymphomas in response to oncogenic Ras . This work has important implications for both tumour development and tumour therapy. Michaloglou et al . report that oncogene-induced senescence may be a physiologically important process in humans, keeping moles in a benign state for many years: unchecked they develop into malignant melanomas. Chen et al . also find that cellular senescence blocks tumorigenesis in vivo : they show that acting together, the p53 tumour suppressor and the cellular senescence system can prevent prostate cancer induction in mice by the PTEN mutation. Collado et al . show that cellular senescence is a defining feature of Ras-initiated premalignant tumours; this could prove valuable in the diagnosis and prognosis of cancer. See the web focus . Cellular senescence has been theorized to oppose neoplastic transformation triggered by activation of oncogenic pathways in vitro 1 , 2 , 3 , but the relevance of senescence in vivo has not been established. The PTEN and p53 tumour suppressors are among the most commonly inactivated or mutated genes in human cancer including prostate cancer 4 , 5 . Although they are functionally distinct, reciprocal cooperation has been proposed, as PTEN is thought to regulate p53 stability, and p53 to enhance PTEN transcription 6 , 7 , 8 , 9 , 10 . Here we show that conditional inactivation of Trp53 in the mouse prostate fails to produce a tumour phenotype, whereas complete Pten inactivation in the prostate triggers non-lethal invasive prostate cancer after long latency. Strikingly, combined inactivation of Pten and Trp53 elicits invasive prostate cancer as early as 2 weeks after puberty and is invariably lethal by 7 months of age. Importantly, acute Pten inactivation induces growth arrest through the p53-dependent cellular senescence pathway both in vitro and in vivo , which can be fully rescued by combined loss of Trp53 . Furthermore, we detected evidence of cellular senescence in specimens from early-stage human prostate cancer. Our results demonstrate the relevance of cellular senescence in restricting tumorigenesis in vivo and support a model for cooperative tumour suppression in which p53 is an essential failsafe protein of Pten -deficient tumours.

The transcription factor Zbtb7a was previously described as an oncogene in non-Hodgkin lymphoma. Now, Pier Paolo Pandolfi and colleagues report that loss of Zbtb7a accelerates the progression of invasive prostate tumorigenesis in Pten -null mice and shows evidence of monoallelic loss in 18% of individuals with advanced prostate cancer. Zbtb7a has previously been described as a powerful proto-oncogene. Here we unexpectedly demonstrate that Zbtb7a has a critical oncosuppressive role in the prostate. Prostate-specific inactivation of Zbtb7a leads to a marked acceleration of Pten loss–driven prostate tumorigenesis through bypass of Pten loss–induced cellular senescence (PICS). We show that ZBTB7A physically interacts with SOX9 and functionally antagonizes its transcriptional activity on key target genes such as MIA , which is involved in tumor cell invasion, and H19 , a long noncoding RNA precursor for an RB -targeting microRNA. Inactivation of Zbtb7a in vivo leads to Rb downregulation, PICS bypass and invasive prostate cancer. Notably, we found that ZBTB7A is genetically lost, as well as downregulated at both the mRNA and protein levels, in a subset of human advanced prostate cancers. Thus, we identify ZBTB7A as a context-dependent cancer gene that can act as an oncogene in some contexts but also has oncosuppressive-like activity in PTEN -null tumors.

Nuclear receptor tyrosine kinases (nRTKs) are aberrantly upregulated in many types of cancers, but the regulation of nRTK remains unclear. We previously showed androgen deprivation therapy (ADT) induces nMET in castration-resistant prostate cancer (CRPC) specimens. Through gene expression microarray profiles reanalysis, we identified that nMET signaling requires ARF for CRPC growth in Pten/Trp53 conditional knockout mouse model. Accordingly, aberrant MET/nMET elevation correlates with ARF in human prostate cancer (PCa) specimens. Mechanistically, ARF elevates nMET through binding to MET cytoplasmic domain to stabilize MET. Furthermore, carbon nanodots resensitize cancer cells to MET inhibitors through DNA damage response. The inhibition of phosphorylation by carbon nanodots was identified through binding to phosphate group of phospho-tyrosine via computational calculation and experimental assay. Thus, nMET is essential to precision therapy of MET inhibitor. Our findings reveal for the first time that targeting nMET axis by carbon nanodots can be a novel avenue for overcoming drug resistance in cancers especially prostate cancer.