Molecular mechanisms underlying gene regulatory variation of maize metabolic traits.

Variation in gene expression levels is pervasive among individuals and races or varieties, and has substantial agronomic consequences, for example, by contributing to hybrid vigor. Gene expression level variation results from mutations in regulatory sequences (cis) and/or transcription factor (TF) activity (trans), but the mechanisms underlying cis- and/or trans-regulatory variation of complex phenotypes remain largely unknown. Here, we investigated gene expression variation mechanisms underlying the differential accumulation of the insecticidal compounds maysin and chlorogenic acid in silks of widely used maize (Zea mays) inbreds, B73 and A632. By combining transcriptomics and cistromics, we identified 1,338 silk direct targets of the maize R2R3-MYB TF Pericarp color1 (P1), consistent with it being a regulator of maysin and chlorogenic acid biosynthesis. Among these P1 targets, 464 showed allele-specific expression (ASE) between B73 and A632 silks. Allelic DNA-affinity purification sequencing identified 34 examples in which P1 allelic specific binding (ASB) correlated with cis-expression variation. From previous yeast one-hybrid studies, we identified 9 TFs potentially implicated in the control of P1 targets, with ASB to 83 out of 464 ASE genes (cis) and differential expression of 4 out of 9 TFs between B73 and A632 silks (trans). These results provide a molecular framework for understanding universal mechanisms underlying natural variation of gene expression levels, and how the regulation of metabolic diversity is established.

Role of Heterogeneous Nuclear Ribonucleoproteins in the Cancer-Immune Landscape.

Cancer remains the second leading cause of death, accounting for approximately 20% of all fatalities. Evolving cancer cells and a dysregulated immune system create complex tumor environments that fuel tumor growth, metastasis, and resistance. Over the past decades, significant progress in deciphering cancer cell behavior and recognizing the immune system as a hallmark of tumorigenesis has been achieved. However, the underlying mechanisms controlling the evolving cancer-immune landscape remain mostly unexplored. Heterogeneous nuclear ribonuclear proteins (hnRNP), a highly conserved family of RNA-binding proteins, have vital roles in critical cellular processes, including transcription, post-transcriptional modifications, and translation. Dysregulation of hnRNP is a critical contributor to cancer development and resistance. HnRNP contribute to the diversity of tumor and immune-associated aberrant proteomes by controlling alternative splicing and translation. They can also promote cancer-associated gene expression by regulating transcription factors, binding to DNA directly, or promoting chromatin remodeling. HnRNP are emerging as newly recognized mRNA readers. Here, we review the roles of hnRNP as regulators of the cancer-immune landscape. Dissecting the molecular functions of hnRNP will provide a better understanding of cancer-immune biology and will impact the development of new approaches to control and treat cancer.

Ibrutinib Blocks YAP1 Activation and Reverses BRAF Inhibitor Resistance in Melanoma Cells.

Most B-Raf proto-oncogene (BRAF)-mutant melanoma tumors respond initially to BRAF inhibitor (BRAFi)/mitogen-activated protein kinase kinase 1 inhibitor (MEKi) therapy, although few patients have durable long-term responses to these agents. The goal of this study was to use an unbiased computational approach to identify inhibitors that reverse an experimentally derived BRAFi resistance gene expression signature. Using this approach, we found that ibrutinib effectively reverses this signature, and we demonstrate experimentally that ibrutinib resensitizes a subset of BRAFi-resistant melanoma cells to vemurafenib. Ibrutinib is used clinically as an inhibitor of the Src family kinase Bruton tyrosine kinase (BTK); however, neither BTK deletion nor treatment with acalabrutinib, another BTK inhibitor with reduced off-target activity, resensitized cells to vemurafenib. These data suggest that ibrutinib acts through a BTK-independent mechanism in vemurafenib resensitization. To better understand this mechanism, we analyzed the transcriptional profile of ibrutinib-treated BRAFi-resistant melanoma cells and found that the transcriptional profile of ibrutinib was highly similar to that of multiple Src proto-oncogene kinase inhibitors. Since ibrutinib, but not acalabrutinib, has appreciable off-target activity against multiple Src family kinases, it suggests that ibrutinib may be acting through this mechanism. Furthermore, genes that are differentially expressed in ibrutinib-treated cells are enriched in Yes1-associated transcriptional regulator (YAP1) target genes, and we showed that ibrutinib, but not acalabrutinib, reduces YAP1 activity in BRAFi-resistant melanoma cells. Taken together, these data suggest that ibrutinib, or other Src family kinase inhibitors, may be useful for treating some BRAFi/MEKi-refractory melanoma tumors. SIGNIFICANCE STATEMENT: MAPK-targeted therapies provide dramatic initial responses, but resistance develops rapidly; a subset of these tumors may be rendered sensitive again by treatment with an approved Src family kinase inhibitor-ibrutinub-potentially providing improved clinical outcomes.

Anti-Inflammatory Mechanisms of Dietary Flavones: Tapping into Nature to Control Chronic Inflammation in Obesity and Cancer.

Flavones are natural phytochemicals broadly distributed in our diet. Their anti-inflammatory properties provide unique opportunities to control the innate immune system and inflammation. Here, we review the role of flavones in chronic inflammation with an emphasis on their impact on the molecular mechanisms underlying inflammatory diseases including obesity and cancer. Flavones can influence the innate immune cell repertoire restoring the immune landscape. Flavones impinge on NF-κB, STAT, COX-2, or NLRP3 inflammasome pathways reestablishing immune homeostasis. Devoid of adverse side effects, flavones could present alternative opportunities for the treatment and prevention of chronic inflammation that contributes to obesity and cancer.

Caspase-11 promotes the fusion of phagosomes harboring pathogenic bacteria with lysosomes by modulating actin polymerization.

Inflammasomes are multiprotein complexes that include members of the NLR (nucleotide-binding domain leucine-rich repeat containing) family and caspase-1. Once bacterial molecules are sensed within the macrophage, the inflammasome is assembled, mediating the activation of caspase-1. Caspase-11 mediates caspase-1 activation in response to lipopolysaccharide and bacterial toxins, and yet its role during bacterial infection is unknown. Here, we demonstrated that caspase-11 was dispensable for caspase-1 activation in response to Legionella, Salmonella, Francisella, and Listeria. We also determined that active mouse caspase-11 was required for restriction of L. pneumophila infection. Similarly, human caspase-4 and caspase-5, homologs of mouse caspase-11, cooperated to restrict L. pneumophila infection in human macrophages. Caspase-11 promoted the fusion of the L. pneumophila vacuole with lysosomes by modulating actin polymerization through cofilin. However, caspase-11 was dispensable for the fusion of lysosomes with phagosomes containing nonpathogenic bacteria, uncovering a fundamental difference in the trafficking of phagosomes according to their cargo.

The Targeted Impact of Flavones on Obesity-Induced Inflammation and the Potential Synergistic Role in Cancer and the Gut Microbiota.

Obesity is an inflammatory disease that is approaching pandemic levels, affecting nearly 30% of the world's total population. Obesity increases the risk of diabetes, cardiovascular disorders, and cancer, consequentially impacting the quality of life and imposing a serious socioeconomic burden. Hence, reducing obesity and related life-threatening conditions has become a paramount health challenge. The chronic systemic inflammation characteristic of obesity promotes adipose tissue remodeling and metabolic changes. Macrophages, the major culprits in obesity-induced inflammation, contribute to sustaining a dysregulated immune function, which creates a vicious adipocyte-macrophage crosstalk, leading to insulin resistance and metabolic disorders. Therefore, targeting regulatory inflammatory pathways has attracted great attention to overcome obesity and its related conditions. However, the lack of clinical efficacy and the undesirable side-effects of available therapeutic options for obesity provide compelling reasons for the need to identify additional approaches for the prevention and treatment of obesity-induced inflammation. Plant-based active metabolites or nutraceuticals and diets with an increased content of these compounds are emerging as subjects of intense scientific investigation, due to their ability to ameliorate inflammatory conditions and offer safe and cost-effective opportunities to improve health. Flavones are a class of flavonoids with anti-obesogenic, anti-inflammatory and anti-carcinogenic properties. Preclinical studies have laid foundations by establishing the potential role of flavones in suppressing adipogenesis, inducing browning, modulating immune responses in the adipose tissues, and hindering obesity-induced inflammation. Nonetheless, the understanding of the molecular mechanisms responsible for the anti-obesogenic activity of flavones remains scarce and requires further investigations. This review recapitulates the molecular aspects of obesity-induced inflammation and the crosstalk between adipocytes and macrophages, while focusing on the current evidence on the health benefits of flavones against obesity and chronic inflammation, which has been positively correlated with an enhanced cancer incidence. We conclude the review by highlighting the areas of research warranting a deeper investigation, with an emphasis on flavones and their potential impact on the crosstalk between adipocytes, the immune system, the gut microbiome, and their role in the regulation of obesity.

Core Promoter Plasticity Between Maize Tissues and Genotypes Contrasts with Predominance of Sharp Transcription Initiation Sites.

Core promoters are crucial for gene regulation, providing blueprints for the assembly of transcriptional machinery at transcription start sites (TSSs). Empirically, TSSs define the coordinates of core promoters and other regulatory sequences. Thus, experimental TSS identification provides an essential step in the characterization of promoters and their features. Here, we describe the application of CAGE (cap analysis of gene expression) to identify genome-wide TSSs used in root and shoot tissues of two maize (Zea mays) inbred lines (B73 and Mo17). Our studies indicate that most TSS clusters are sharp in maize, similar to mice, but distinct from Arabidopsis thaliana, Drosophila melanogaster, or zebra fish, in which a majority of genes have broad-shaped TSS clusters. We established that ∼38% of maize promoters are characterized by a broader TATA-motif consensus, and this motif is significantly enriched in genes with sharp TSSs. A noteworthy plasticity in TSS usage between tissues and inbreds was uncovered, with ∼1500 genes showing significantly different dominant TSSs, sometimes affecting protein sequence by providing alternate translation initiation codons. We experimentally characterized instances in which this differential TSS utilization results in protein isoforms with additional domains or targeted to distinct subcellular compartments. These results provide important insights into TSS selection and gene expression in an agronomically important crop.

MicroRNAs Targeting Caspase-3 and -7 in PANC-1 Cells.

MicroRNAs (miRNAs), a critical part of the RNA silencing machinery, are known to play important regulatory roles in cancer. However, the consequence of miRNA deregulation in cancer is unknown for many miRNAs. Here, we define that miRNAs, miR-17-5p, miR-132-3p/-212-3p, and miR-337-3p are significantly up-regulated in the pancreatic ductal adenocarcinomas (PDAC) compared to the normal and benign tissues. Furthermore, by using PANC-1 cells, we demonstrate that overexpressed miR-337-3p and miR-17-5p/miR-132-3p/-212-3p can regulate executioner caspases-3 and -7, respectively. In addition, over-expression of miRNAs, especially miR-337-3p, attenuates tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) cytotoxicity in PANC-1 cells. Our findings unveil an important biological function for miRNAs up-regulated in PDAC in coordinately regulating caspases, potentially contributing to the malignant progression of PDAC.

Molecular basis for the action of a dietary flavonoid revealed by the comprehensive identification of apigenin human targets.

Flavonoids constitute the largest class of dietary phytochemicals, adding essential health value to our diet, and are emerging as key nutraceuticals. Cellular targets for dietary phytochemicals remain largely unknown, posing significant challenges for the regulation of dietary supplements and the understanding of how nutraceuticals provide health value. Here, we describe the identification of human cellular targets of apigenin, a flavonoid abundantly present in fruits and vegetables, using an innovative high-throughput approach that combines phage display with second generation sequencing. The 160 identified high-confidence candidate apigenin targets are significantly enriched in three main functional categories: GTPase activation, membrane transport, and mRNA metabolism/alternative splicing. This last category includes the heterogeneous nuclear ribonucleoprotein A2 (hnRNPA2), a factor involved in splicing regulation, mRNA stability, and mRNA transport. Apigenin binds to the C-terminal glycine-rich domain of hnRNPA2, preventing hnRNPA2 from forming homodimers, and therefore, it perturbs the alternative splicing of several human hnRNPA2 targets. Our results provide a framework to understand how dietary phytochemicals exert their actions by binding to many functionally diverse cellular targets. In turn, some of them may modulate the activity of a large number of downstream genes, which is exemplified here by the effects of apigenin on the alternative splicing activity of hnRNPA2. Hence, in contrast to small-molecule pharmaceuticals designed for defined target specificity, dietary phytochemicals affect a large number of cellular targets with varied affinities that, combined, result in their recognized health benefits.

Dietary Apigenin Exerts Immune-Regulatory Activity in Vivo by Reducing NF-κB Activity, Halting Leukocyte Infiltration and Restoring Normal Metabolic Function.

The increasing prevalence of inflammatory diseases and the adverse effects associated with the long-term use of current anti-inflammatory therapies prompt the identification of alternative approaches to reestablish immune balance. Apigenin, an abundant dietary flavonoid, is emerging as a potential regulator of inflammation. Here, we show that apigenin has immune-regulatory activity in vivo. Apigenin conferred survival to mice treated with a lethal dose of Lipopolysaccharide (LPS) restoring normal cardiac function and heart mitochondrial Complex I activity. Despite the adverse effects associated with high levels of splenocyte apoptosis in septic models, apigenin had no effect on reducing cell death. However, we found that apigenin decreased LPS-induced apoptosis in lungs, infiltration of inflammatory cells and chemotactic factors' accumulation, re-establishing normal lung architecture. Using NF-κB luciferase transgenic mice, we found that apigenin effectively modulated NF-κB activity in the lungs, suggesting the ability of dietary compounds to exert immune-regulatory activity in an organ-specific manner. Collectively, these findings provide novel insights into the underlying immune-regulatory mechanisms of dietary nutraceuticals in vivo.

The Maize TFome--development of a transcription factor open reading frame collection for functional genomics.

Establishing the architecture of the gene regulatory networks (GRNs) responsible for controlling the transcription of all genes in an organism is a natural development that follows elucidation of the genome sequence. Reconstruction of the GRN requires the availability of a series of molecular tools and resources that so far have been limited to a few model organisms. One such resource consists of collections of transcription factor (TF) open reading frames (ORFs) cloned into vectors that facilitate easy expression in plants or microorganisms. In this study, we describe the development of a publicly available maize TF ORF collection (TFome) of 2034 clones corresponding to 2017 unique gene models in recombination-ready vectors that make possible the facile mobilization of the TF sequences into a number of different expression vectors. The collection also includes several hundred co-regulators (CoREGs), which we classified into well-defined families, and for which we propose here a standard nomenclature, as we have previously done for TFs. We describe the strategies employed to overcome the limitations associated with cloning ORFs from a genome that remains incompletely annotated, with a partial full-length cDNA set available, and with many TF/CoREG genes lacking experimental support. In many instances this required the combination of genome-wide expression data with gene synthesis approaches. The strategies developed will be valuable for developing similar resources for other agriculturally important plants. Information on all the clones generated is available through the GRASSIUS knowledgebase (http://grassius.org/).

Distinct contribution of protein kinase Cδ and protein kinase Cε in the lifespan and immune response of human blood monocyte subpopulations.

Monocytes, key components of the immune system, are a heterogeneous population comprised of classical monocytes (CD16(-) ) and non-classical monocytes (CD16(+) ). Monocytes are short lived and undergo spontaneous apoptosis, unless stimulated. Dysregulation of monocyte numbers contribute to the pathophysiology of inflammatory diseases, yet the contribution of each subset remains poorly characterized. Protein kinase C (PKC) family members are central to monocyte biology; however, their role in regulating lifespan and immune function of CD16(-) and CD16(+) monocytes has not been studied. Here, we evaluated the contribution of PKCδ and PKCε in the lifespan and immune response of both monocyte subsets. We showed that CD16(+) monocytes are more susceptible to spontaneous apoptosis because of the increased caspase-3, -8 and -9 activities accompanied by higher kinase activity of PKCδ. Silencing of PKCδ reduced apoptosis in both CD16(+) and CD16(-) monocytes. CD16(+) monocytes express significantly higher levels of PKCε and produce more tumour necrosis factor-α in CD16(+) compared with CD16(-) monocytes. Silencing of PKCε affected the survival and tumour necrosis factor-α production. These findings demonstrate a complex network with similar topography, yet unique regulatory characteristics controlling lifespan and immune response in each monocyte subset, helping define subset-specific coordination programmes controlling monocyte function.

Chaperone peptides of α-crystallin inhibit epithelial cell apoptosis, protein insolubilization, and opacification in experimental cataracts.

α-Crystallin is a member of the small heat-shock protein (sHSP) family and consists of two subunits, αA and αB. Both αA- and αB-crystallin act as chaperones and anti-apoptotic proteins. Previous studies have identified the peptide (70)KFVIFLDVKHFSPEDLTVK(88) in αA-crystallin and the peptide (73)DRFSVNLDVKHFSPEELKVK(92) in αB-crystallin as mini-chaperones. In the human lens, lysine 70 (Lys(70)) of αA and Lys(92) of αB (in the mini-chaperone sequences) are acetylated. In this study, we investigated the cellular effects of the unmodified and acetyl mini-chaperones. The αA- and αB-crystallin peptides inhibited stress-induced aggregation of four client proteins, and the αA-acetyl peptide was more effective than the native peptide against three of the client proteins. Both the acetyl and native crystallin peptides inhibited stress-induced apoptosis in two mammalian cell types, and this property was directly related to the inhibition of cytochrome c release from mitochondria and the activity of caspase-3 and -9. In organ-cultured rat lenses, the peptides inhibited calcimycin-induced epithelial cell apoptosis. Intraperitoneal injection of the peptides inhibited cataract development in selenite-treated rats, which was accompanied by inhibition of oxidative stress, protein insolubilization, and caspase activity in the lens. These inhibitory effects were more pronounced for acetyl peptides than native peptides. A scrambled αA-crystallin peptide produced no such effects. The results suggest that the α-crystallin chaperone peptides could be used as therapeutic agents to treat cataracts and diseases in which protein aggregation and apoptosis are contributing factors.

Apigenin protects endothelial cells from lipopolysaccharide (LPS)-induced inflammation by decreasing caspase-3 activation and modulating mitochondrial function.

Acute and chronic inflammation is characterized by increased reactive oxygen species (ROS) production, dysregulation of mitochondrial metabolism and abnormal immune function contributing to cardiovascular diseases and sepsis. Clinical and epidemiological studies suggest potential beneficial effects of dietary interventions in inflammatory diseases but understanding of how nutrients work remains insufficient. In the present study, we evaluated the effects of apigenin, an anti-inflammatory flavonoid abundantly found in our diet, in endothelial cells during inflammation. Here, we show that apigenin reduced lipopolysaccharide (LPS)-induced apoptosis by decreasing ROS production and the activity of caspase-3 in endothelial cells. Apigenin conferred protection against LPS-induced mitochondrial dysfunction and reestablished normal mitochondrial complex I activity, a major site of electron leakage and superoxide production, suggesting its ability to modulate endothelial cell metabolic function during inflammation. Collectively, these findings indicate that the dietary compound apigenin stabilizes mitochondrial function during inflammation preventing endothelial cell damage and thus provide new translational opportunities for the use of dietary components in the prevention and treatment of inflammatory diseases.

Tart Cherry (Prunus cerasus L.) Pit Extracts Protect Human Skin Cells against Oxidative Stress: Unlocking Sustainable Uses for Food Industry Byproducts.

Industrial processing of tart cherries (Prunus cerasus L.) produces bioproducts like cherry pits (CP), which contribute to adverse environmental effects. To identify sustainable strategies to minimize the environmental impact of cherry processing, we investigated their potential value as antioxidants for prospective utilization within cosmeceutical applications. Untargeted metabolomic analyses of water and water: ethanol CP extracts using an eco-friendly technique revealed significant enrichment in coumaroyl derivatives and flavonoids with congruent metabolite representation regardless of the extraction solvent. The antioxidant activity of tart CP extracts was evaluated on human skin cells exposed to H2O2 or LPS, modeling environmentally induced oxidants. Notably, both CP extracts provide antioxidant activity by reducing H2O2 or LPS-induced ROS in human skin keratinocytes without affecting cell viability. The CP extracts increased the expression of CAT and SOD1 genes encoding antioxidant regulatory enzymes while decreasing the expression of NOS2, a pro-oxidant regulator. These findings reveal the antioxidant properties of tart CP, offering new opportunities to produce natural-based skin care products and adding economic value while providing sustainable options to reduce the environmental impact of food byproducts.

Arachidin-1, a Prenylated Stilbenoid from Peanut, Enhances the Anticancer Effects of Paclitaxel in Triple-Negative Breast Cancer Cells.

Triple-negative breast cancer (TNBC) is one of the deadliest forms of breast cancer. Investigating alternative therapies to increase survival rates for this disease is essential. To this end, the cytotoxic effects of the prenylated stilbenoids arachidin-1 (A-1) and arachidin-3 (A-3), and non-prenylated resveratrol (RES) were evaluated in human TNBC cell lines as potential adjuvants for paclitaxel (Pac). A-1, alone or in combination with Pac, showed the highest cytotoxicity in TNBC cells. Apoptosis was further evaluated by measuring key apoptosis marker proteins, cell cycle arrest, and intracellular reactive oxygen species (ROS) generation. Furthermore, the cytotoxic effect of A-1 combined with Pac was also evaluated in a 3D spheroid TNBC model. The results showed that A-1 decreased the Pac IC50 approximately 2-fold in TNBC cells. The synergistic combination of A-1 and Pac arrested cells in G2/M phase and activated p53 expression. In addition, the combined treatment increased intracellular ROS generation and induced apoptosis. Importantly, the combination of A-1 with Pac inhibited TNBC spheroid growth. Our results demonstrated that A-1 in combination with Pac inhibited cell proliferation, induced apoptosis through mitochondrial oxidative stress, and reduced TNBC spheroid growth. These findings underscore the impactful effects of the prenylated stilbenoid A-1 as a novel adjuvant for Pac chemotherapy in TNBC treatment.

Transcriptome reprogramming through alternative splicing triggered by apigenin drives cell death in triple-negative breast cancer.

Triple-negative breast cancer (TNBC) is characterized by its aggressiveness and resistance to cancer-specific transcriptome alterations. Alternative splicing (AS) is a major contributor to the diversification of cancer-specific transcriptomes. The TNBC transcriptome landscape is characterized by aberrantly spliced isoforms that promote tumor growth and resistance, underscoring the need to identify approaches that reprogram AS circuitry towards transcriptomes, favoring a delay in tumorigenesis or responsiveness to therapy. We have previously shown that flavonoid apigenin is associated with splicing factors, including heterogeneous nuclear ribonucleoprotein A2 (hnRNPA2). Here, we showed that apigenin reprograms TNBC-associated AS transcriptome-wide. The AS events affected by apigenin were statistically enriched in hnRNPA2 substrates. Comparative transcriptomic analyses of human TNBC tumors and non-tumor tissues showed that apigenin can switch cancer-associated alternative spliced isoforms (ASI) to those found in non-tumor tissues. Apigenin preferentially affects the splicing of anti-apoptotic and proliferation factors, which are uniquely observed in cancer cells, but not in non-tumor cells. Apigenin switches cancer-associated aberrant ASI in vivo in TNBC xenograft mice by diminishing proliferation and increasing pro-apoptotic ASI. In accordance with these findings, apigenin increased apoptosis and reduced tumor proliferation, thereby halting TNBC growth in vivo. Our results revealed that apigenin reprograms transcriptome-wide TNBC-specific AS, thereby inducing apoptosis and hindering tumor growth. These findings underscore the impactful effects of nutraceuticals in altering cancer transcriptomes, offering new options to influence outcomes in TNBC treatments.

The small heat shock protein 27 is a key regulator of CD8+ CD57+ lymphocyte survival.

Differences in CD8(+)CD57(-) and CD8(+)CD57(+) lymphocyte lifespan have been documented. Lower numbers and shorter lifespan are characteristic of CD8(+)CD57(+) in normal individuals. However, CD8(+)CD57(+) are expanded in certain disease states including T cell large granular leukemia and other hematologic malignancies. The mechanisms responsible for the differences in CD8(+)CD57(-) and CD8(+)CD57(+) lifespan remain elusive. In this study, we demonstrate that the small heat shock protein (Hsp) 27 is a key regulator of CD8(+)CD57(+) lymphocyte lifespan. We found that Hsp27 expression is significantly lower in CD8(+)CD57(+) than in CD8(+)CD57(-) lymphocytes. In contrast, Hsp60 and Hsp70 are expressed at comparable levels. Unlike other antiapoptotic Bcl-2-like molecules, the expression of Hsp27 tightly correlates with CD8(+)CD57(+) and CD8(+)CD57(-) lifespan. We demonstrate that Hsp27 overexpression in CD8(+)CD57(+) lymphocytes to levels found normally in CD8(+)CD57(-) lymphocytes decreased apoptosis. Accordingly, silencing of Hsp27 in CD8(+)CD57(-) lymphocytes increased apoptosis. Collectively these results demonstrate that Hsp27 is a critical regulator of normal CD8(+)CD57(+) lifespan supporting its use as a marker of lifespan in this lineage, and suggest a mechanism responsible for the decreased apoptosis and clonal expansion characteristic of certain disease states.

Bioengineering of Genetically Encoded Gene Promoter Repressed by the Flavonoid Apigenin for Constructing Intracellular Sensor for Molecular Events.

In recent years, Synthetic Biology has emerged as a new discipline where functions that were traditionally performed by electronic devices are replaced by "cellular devices"; genetically encoded circuits constructed of DNA that are built from biological parts (aka bio-parts). The cellular devices can be used for sensing and responding to natural and artificial signals. However, a major challenge in the field is that the crosstalk between many cellular signaling pathways use the same signaling endogenous molecules that can result in undesired activation. To overcome this problem, we utilized a specific promoter that can activate genes with a natural, non-toxic ligand at a highly-induced transcription level with low background or undesirable off-target expression. Here we used the orphan aryl hydrocarbon receptor (AHR), a ligand-activated transcription factor that upon activation binds to specific AHR response elements (AHRE) of the Cytochrome P450, family 1, subfamily A, polypeptide 1 (CYP1A1) promoter. Flavonoids have been identified as AHR ligands. Data presented here show the successful creation of a synthetic gene "off" switch that can be monitored directly using an optical reporter gene. This is the first step towards bioengineering of a synthetic, nanoscale bio-part for constructing a sensor for molecular events.

Splicing reprogramming of TRAIL/DISC-components sensitizes lung cancer cells to TRAIL-mediated apoptosis.

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) selective killing of cancer cells underlines its anticancer potential. However, poor tolerability and resistance underscores the need to identify cancer-selective TRAIL-sensitizing agents. Apigenin, a dietary flavonoid, sensitizes lung cancer cell lines to TRAIL. It remains unknown, however, whether apigenin sensitizes primary lung cancer cells to TRAIL and its underlying mechanisms. Here we show that apigenin reprograms alternative splicing of key TRAIL/death-inducing-signaling-complex (DISC) components: TRAIL Death Receptor 5 (DR5) and cellular-FLICE-inhibitory-protein (c-FLIP) by interacting with the RNA-binding proteins hnRNPA2 and MSI2, resulting in increased DR5 and decreased c-FLIPS protein levels, enhancing TRAIL-induced apoptosis of primary lung cancer cells. In addition, apigenin directly bound heat shock protein 70 (Hsp70), promoting TRAIL/DISC assembly and triggering apoptosis. Our findings reveal that apigenin directs alternative splicing and inhibits Hsp70 enhancing TRAIL anticancer activity. These findings underscore impactful synergies between diet and cancer treatments opening new avenues for improved cancer treatments.