Inhibition Of Transcriptional Activity Research Articles

MIKC type MADS-box transcription factor LcSVP2 is involved in dormancy regulation of the terminal buds in evergreen perennial litchi (Litchi chinensis Sonn.)

Abstract SHORT VEGETATIVE PHASE (SVP), a member of the MADS-box transcription factor family, has been reported to regulate bud dormancy in deciduous perennial plants. Previously, three LcSVPs were identified from litchi genome, and LcSVP2 was highly expressed in the terminal buds of litchi during growth cessation or dormancy stages and down-regulated during growth stages. In this study, the roles of LcSVP2 in governing litchi bud dormancy was examined. LcSVP2 was highly expressed in the shoots, especially in the terminal buds at growth cessation stage, whereas low expression was showed in roots, female flowers and seeds. LcSVP2 was found to be located in the nucleus and have transcription inhibitory activity. Over-expression of LcSVP2 in Arabidopsis thaliana resulted in a later flowering phenotype compared to the wild-type control. Silencing LcSVP2 in growing litchi terminal buds delayed re-entry of dormancy, resulting in significantly lower dormancy rate. The treatment also significantly up-regulated litchi FLOWERING LOCUS T2 (LcFT2). Further study indicates that LcSVP2 interacts with an AP2-type transcription factor, SMALL ORGAN SIZE1 (LcSMOS1). Silencing LcSMOS1 promoted budbreak and delayed bud dormancy. ABA (200 mg/L), which enforced bud dormancy, induced a short-term increase in the expression of LcSVP2 and LcSMOS1. Our study reveals that LcSVP2 may play a crucial role, likely together with LcSMOS1, in dormancy onset of the terminal bud and may also serve as a flowering repressor in evergreen perennial litchi.

HDAC Inhibition Increases CXCL12 Secretion to Recruit Natural Killer Cells in Peripheral T Cell Lymphoma.

Peripheral T cell lymphoma (PTCL) is a heterogeneous and aggressive disease with a poor prognosis. Histone deacetylase (HDAC) inhibitors have shown inhibitory effects on PTCL. A better understanding of the therapeutic mechanism underlying the effects of HDAC inhibitors could help improve treatment strategies. Here, we found that high expression of HDAC3 is associated with poor prognosis in PTCL. HDAC3 inhibition suppressed lymphoma growth in immunocompetent mice but not in immunodeficient mice. HDAC3 deletion delayed the progression of lymphoma, reduced the lymphoma burden in the thymus, spleen, and lymph nodes, and prolonged the survival of mice bearing MNU-induced lymphoma. Furthermore, inhibiting HDAC3 promoted the infiltration and enhanced the function of natural killer (NK) cells. Mechanistically, HDAC3 mediated ATF3 deacetylation, enhancing its transcriptional inhibitory activity. Targeting HDAC3 enhanced CXCL12 secretion through an ATF3-dependent pathway to stimulate NK cell recruitment and activation. Finally, HDAC3 suppression improved the response of PTCL to conventional chemotherapy. Collectively, this study provides insights into the mechanism by which HDAC3 regulates ATF3 activity and CXCL12 secretion, leading to immune infiltration and lymphoma suppression. Combining HDAC3 inhibitors with chemotherapy may be a promising strategy for treating PTCL. Key words: Histone deacetylases (HDACs), Natural killer (NK) cells, Peripheral T cell lymphoma (PTCL).

Genome-wide identification of the CclKNOX gene family and functional characterization of CclKNOX3 and CclKNOX5 in citrus shoot development

KNOTTED1-LIKE HOMEOBOX (KNOX) genes are a relatively conserved gene family in plants, and have important regulatory functions in the morphological development of plants. In this study, a total of 9 KNOX proteins were found from citrus and divided into two classes, Class I and Class II. Subsequently, their gene structures, protein characteristics and sequence features were analyzed. Spatial expression analysis showed that most of the genes exhibited a constitutive expression pattern in different tissues of Citrus clementina. Interestingly, the expression pattern of CclKNOX3 was different from other Class I members, as it was mainly expressed in stems, lateral buds and shoot tips. Overexpression of CclKNOX3 led to strong differentiation of shoot apical meristem and curled leaves in transgenic tobacco and lemon. In addition, CclKNOX3 was found to interact with CclKNOX5, localized in the nucleus and have transcriptional inhibitory activity. Further transgenic analysis found that 35S:CclKNOX5 transgenic tobacco showed similar phenotype with 35S:CclKNOX3. Furthermore, yeast one hybrid and luciferase assay confirmed that CclKNOX3 and CclKNOX5 were regulated by CclKNOX4. This study expands our knowledge about the citrus KNOX family and provides valuable informations for future studies on shoot developmental regulation.

Structure-activity relationship and biological evaluation of xanthine derivatives as PCSK9 inhibitors for the treatment of atherosclerosis

Developing non-statin small molecules for the treatment of hypercholesterolemia remains challenging. The proprotein convertase subtilisin/kexin type 9 (PCSK9)-targeted therapies have attracted considerable attentions. Forty-five 7030B-C5 derivatives were synthesized and evaluated for the PCSK9 repression activity, taking the PCSK9 transcriptional inhibitor 7030B-C5 as the lead. Structure-activity relationship (SAR) analysis at C8 and N7-position was carried out, and compound 3s and 5r exhibited comparable PCSK9 transcriptional inhibitory activity but much lower cytotoxicity with the therapeutic index (TI) values doubled of that of 7030B-C5. In the in vitro assay, both compounds significantly reduced the level of PCSK9 protein and increased LDL receptor (LDLR) protein level. What's more, both compounds promoted LDL cholesterol (LDL-C) clearance more efficiently than 7030B-C5 in HepG2 cells. Most importantly, compound 3s reduced the atherosclerotic plaque areas with promising lipid-lowing effects in ApoE KO mice with a higher in vivo activity and lower toxicity. The regulatory mechanism of 3s was explored that it might target the transcription factor HNF1α and/or HINFP upstream of PCSK9 transcription, similar to that of 7030B-C5. Thus, 3s was considered as a potential anti-atherosclerosis drug candidate as a novel PCSK9 down-regulatory agent, worthy of further investigations.

A banana transcriptional repressor MaAP2a participates in fruit starch degradation during postharvest ripening.

Fruit postharvest ripening is a crucial course for many fruits with significant conversion of biosubstance, which forms an intricate regulatory network. Ethylene facilitates the ripening process in banana with a remarkable change of fruit starch, but the mechanism adjusting the expression of starch degradation-related enzyme genes is incompletely discovered. Here, we describe a banana APETALA2 transcription factor (MaAP2a) identified as a transcriptional repressor with its powerful transcriptional inhibitory activity. The transcriptional level of MaAP2a gradually decreased with the transition of banana fruit ripening, suggesting a passive role of MaAP2a in banana fruit ripening. Moreover, MaAP2a is a classic nucleoprotein and encompasses transcriptional repressor domain (EAR, LxLxLx). More specifically, protein-DNA interaction assays found that MaAP2a repressed the expression of 15 starch degradation-related genes comprising MaGWD1, MaPWD1, MaSEX4, MaLSF1, MaBAM1-MaBAM3, MaAMY2B/2C/3A/3C, MaMEX1/2, and MapGlcT2-1/2-2 via binding to the GCC-box or AT-rich motif of their promoters. Overall, these results reveal an original MaAP2a-mediated negative regulatory network involved in banana postharvest starch breakdown, which advances our cognition on banana fruit ripening and offers additional reference values for banana varietal improvement.

Overexpression of PeNAC122 gene promotes wood formation and tolerance to osmotic stress in poplars

Finding the adequate balance between wood formation and abiotic stress resistance is still an important challenge for industrial woody crops. In this study, PeNAC122, a member of the NAC transcription factor (TF) family highly expressed in xylem, was cloned from Populus euphratica. Tissue expression and β-glucuronidase (GUS) staining showed that PeNAC122 was exclusively expressed in phloem fiber and secondary xylem of stems. Subcellular and yeast transactivation assays confirmed that PeNAC122 protein existed in the nucleus and did not have transcriptional activation and inhibitory activity. Overexpression of PeNAC122 poplar lines exhibited reduced plant height, thickened xylem, and accumulated lignin content in stems, and also upregulates the expression of secondary cell wall biosynthetic genes. Moreover, overexpression of PeNAC122 lines displayed more tolerance to PEG6000-induced osmotic stress, with stronger photosynthetic performance, higher antioxidant enzyme activity, and less accumulation of reactive oxygen species in leaves, and higher expression levels of stress response genes DREB2A, RD29, and NCED3. These results indicate that PeNAC122 plays a crucial role in wood formation and abiotic stress tolerance, which, in addition to potential use in improving wood quality, provides further insight into the role of NAC family TFs in balancing wood development and abiotic stress resistance.

Discovery of novel ketamine-inspired derivatives as a protective agent against renal ischemic/reperfusion injury in Wistar rats.

Renal ischemia-reperfusion (I/R) injury is a limiting factor for the success of renal grafts and is deemed greatly responsible for the mortality. A novel series of ketamine-inspired compounds was synthesized and subjected to NF-ĸB transcriptional inhibitory activity in LPS-stimulated RAW264.7 cells, where entire set of compounds showed mild-to-moderate significant NF-ĸB transcriptional inhibitory activity (IC50 6.53-67.52µM). Compound 6d showed highest inhibitory activity among the tested series (IC50 2.62µM) and found more potent as compared to ketamine as standard. The effect of compound 6d was further quantified in I/R injury in Wistar rats, where it dose-dependently improves kidney function of rats with significant amelioration of kidney injury as suggested by histopathologic examination of renal tissues. It further showed reduction in the generation of pro-inflammatory cytokines and improves the antioxidant status of experimental rats. Compound 6d inhibited apoptosis and increases the expression of Bcl2 and decreases Bax, and cleaved caspase-3level. It further reduces TLR-4 and NF-κB expression in renal cells of rats, with increases in IκB-α level in Western blot analysis as compared to I/R group. In summary, our current study showed the development of a novel class of ketamine-inspired derivatives against renal ischemia/reperfusion injury.

ZmCCT regulates photoperiod-dependent flowering and response to stresses in maize

BackgroundAppropriate flowering time is very important to the success of modern agriculture. Maize (Zea mays L.) is a major cereal crop, originated in tropical areas, with photoperiod sensitivity. Which is an important obstacle to the utilization of tropical/subtropical germplasm resources in temperate regions. However, the study on the regulation mechanism of photoperiod sensitivity of maize is still in the early stage. Although it has been previously reported that ZmCCT is involved in the photoperiod response and delays maize flowering time under long-day conditions, the underlying mechanism remains unclear.ResultsHere, we showed that ZmCCT overexpression delays flowering time and confers maize drought tolerance under LD conditions. Implementing the Gal4-LexA/UAS system identified that ZmCCT has a transcriptional inhibitory activity, while the yeast system showed that ZmCCT has a transcriptional activation activity. DAP-Seq analysis and EMSA indicated that ZmCCT mainly binds to promoters containing the novel motifs CAAAAATC and AAATGGTC. DAP-Seq and RNA-Seq analysis showed that ZmCCT could directly repress the expression of ZmPRR5 and ZmCOL9, and promote the expression of ZmRVE6 to delay flowering under long-day conditions. Moreover, we also demonstrated that ZmCCT directly binds to the promoters of ZmHY5, ZmMPK3, ZmVOZ1 and ZmARR16 and promotes the expression of ZmHY5 and ZmMPK3, but represses ZmVOZ1 and ZmARR16 to enhance stress resistance. Additionally, ZmCCT regulates a set of genes associated with plant development.ConclusionsZmCCT has dual functions in regulating maize flowering time and stress response under LD conditions. ZmCCT negatively regulates flowering time and enhances maize drought tolerance under LD conditions. ZmCCT represses most flowering time genes to delay flowering while promotes most stress response genes to enhance stress tolerance. Our data contribute to a comprehensive understanding of the regulatory mechanism of ZmCCT in controlling maize flowering time and stress response.

MiR-151a-3p-rich small extracellular vesicles derived from gastric cancer accelerate liver metastasis via initiating a hepatic stemness-enhancing niche.

Liver metastasis (LM) severely affects gastric cancer (GC) patients' prognosis. Small extracellular vesicles (sEVs) play key roles in intercellular communication. Specific sEV-miRNAs from several types of cancer were found to induce a premetastatic niche in target organs before tumor cell arrive. However, whether the primary GC affects hepatic microenvironment or the role of sEV-miRNAs in GC-LM is yet unclear. We report that GC-derived sEVs are primarily absorbed by Kupffer cells (KCs). sEV-miR-151a-3p is highly expressed in GC-LM patients' plasma and presents poor prognosis. Treating mice with sEVs-enriched in miR-151a-3p promotes GC-LM, whereas has no influence on the proliferation of GC cells in situ. Mechanistically, sEV-miR-151a-3p inhibits SP3 in KCs. Simultaneously, sEV-miR-151a-3p targets YTHDF3 to decrease the transcriptional inhibitory activity of SP3 by reducing SUMO1 translation in a N6-methyladenosine-dependent manner. These factors contribute to TGF-β1 transactivation in KCs, subsequently activating the SMAD2/3 pathway and enhancing the stem cell-like properties of incoming GC cells. Furthermore, sEV-miR-151a-3p induces miR-151a-3p transcription in KCs to form a positive feedback loop. In summary, our results reveal a previously unidentified regulatory axis initiated by sEV-miR-151a-3p that establishes a hepatic stemness-permissive niche to support GC-LM. sEV-miR-151a-3p could be a promising diagnostic biomarker and preventive treatment candidate for GC-LM.

Abstract 1295: SJP1901, a small molecule inhibitor targeting hippo pathway by directly inhibiting TEAD palmitoylation in hippo pathway-dependent cancer

Abstract The hippo pathway is a critical transcriptional regulator of cell growth, proliferation, and migration in cancer, furthermore,YAP-TEAD complexes act as a major role in the pathway. S-palmitoylation of cysteine residues in TEAD proteins is required for their stability and function in hippo pathway signaling. Recently, it has become manifested that the dysregulation of hippo pathway effectors (MST1/2 and LATS1/2) is involved in oncogenesis. These effectors inactivate translocation of YAP and TAZ into the nucleus. The translocation of YAP/TAZ is responsible for acting as transcriptional coactivators by binding to the transcription factor, TEADs resulting in the transcription of cancer-related genes that drive tumor growth. Since YAP/TAZ are considered to be natively unfolded and can be difficult to handle as a drug target, TEAD is regarded as an excellent therapeutic target for intervention of the hippo pathway. SJP1901 is a small molecule of TEAD inhibitor with potential as drug candidates in malignant mesothelioma and other types of cancer. Based on the results of structure-based drug design, hit compounds were synthesized and their efficacy was evaluated.The compounds effectively inhibited palmitoylation of TEAD proteins and showed remarkable efficacy in reporter gene assay using TEAD responsive element (TRE)-integrated MCF7 with nano molar IC50 concentrations. The excellent anti-tumor effect of SJP1901 was revealed via cell proliferation inhibition assay (nano molar IC50 concentrations) andanalysis of inhibited transcription activity for target genes (CTGF and CYR61) usingmalignant mesothelia cell lines (NCI-H226, NCI-H2052 and MSTO-211H) known to display hippo pathway-dependent cell growth. In addition, these compounds showed lower toxicities in normal cells such as Fa2N4, CCD-18co and WI38 (IC50>10 μM). In conclusion, we obtained potent small molecules which inactivate TEAD proteins by directly inhibiting their palmitoylation. SJP1901 showed outstanding anti-cancer effects through regulating hippo pathway-mediated target genes and lower toxicitiy in normal cells. In vivo efficacy study and research to expand the indications are currently ongoing. Citation Format: Jihyun Um, Janghyun Lee, Kwangwoo Hwang, Sujin Park, Jooyoung Hyun, Dohyeong Lee, Jeongmin Lee, Li-Kyung Kim, Moon Jung Back, Seong Jun Park, Hwan Jung Lim, You-Keun Shin, Hei-Cheul Jeung, Jaewoong Lee, Hyun Tae Kim, Yongbin Park, Hoseok Kwon, Min-Hyo Ki. SJP1901, a small molecule inhibitor targeting hippo pathway by directly inhibiting TEAD palmitoylation in hippo pathway-dependent cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1295.

Cell-Penetrating CEBPB and CEBPD Leucine Zipper Decoys as Broadly Acting Anti-Cancer Agents.

Simple SummaryThe gene-regulatory factors ATF5, CEBPB and CEBPD promote survival, growth, metastasis and treatment resistance of a range of cancer cell types. Presently, no drugs target all three at once. Here, with the aim of treating cancers, we designed novel cell-penetrating peptides that interact with and inactivate all three. The peptides Bpep and Dpep kill a range of cancer cell types in culture and in animals. In animals with tumors, they also significantly increase survival time. In contrast, they do not affect survival of non-cancer cells and have no apparent side effects in animals. The peptides work in combination with other anti-cancer treatments. Mechanism studies of how the peptides kill cancer cells indicate a decrease in survival proteins and increase in death proteins. These studies support the potential of Bpep and Dpep as novel, safe agents for the treatment of a variety of cancer types, both as mono- and combination therapies.Transcription factors are key players underlying cancer formation, growth, survival, metastasis and treatment resistance, yet few drugs exist to directly target them. Here, we characterized the in vitro and in vivo anti-cancer efficacy of novel synthetic cell-penetrating peptides (Bpep and Dpep) designed to interfere with the formation of active leucine-zipper-based dimers by CEBPB and CEBPD, transcription factors implicated in multiple malignancies. Both peptides similarly promoted apoptosis of multiple tumor lines of varying origins, without such effects on non-transformed cells. Combined with other treatments (radiation, Taxol, chloroquine, doxorubicin), the peptides acted additively to synergistically and were fully active on Taxol-resistant cells. The peptides suppressed expression of known direct CEBPB/CEBPD targets IL6, IL8 and asparagine synthetase (ASNS), supporting their inhibition of transcriptional activation. Mechanisms by which the peptides trigger apoptosis included depletion of pro-survival survivin and a required elevation of pro-apoptotic BMF. Bpep and Dpep significantly slowed tumor growth in mouse models without evident side effects. Dpep significantly prolonged survival in xenograft models. These findings indicate the efficacy and potential of Bpep and Dpep as novel agents to treat a variety of cancers as mono- or combination therapies.

Calycindaphines A-J, Daphniphyllum alkaloids from the roots of Daphniphyllum calycinum.

Ten new Daphniphyllum alkaloids, calycindaphines A–J (1–10), together with seventeen known alkaloids were isolated from the roots of Daphniphyllum calycinum. Their structures were established by extensive spectroscopic methods and compared with data from literature. Compound 1 is a novel alkaloid with a new rearrangement C22 skeleton with the 5/8/7/5/5 ring system. Compound 2 represents the second example of calyciphylline G-type alkaloids. Compound 10 is the first example of secodaphniphylline-type alkaloid absent of the oxygen-bridge between C-25/C-29. The possible biogenetic pathways of 1 and 2 were also proposed. All the isolated compounds were evaluated for their bioactivities in three cell models. Compounds 22, 23, and 26 showed significant NF-κB transcriptional inhibitory activity at a concentration of 50 μM. Compounds 16 and 18 exhibited significant TGF-β inhibitory activity in HepG2 cells. Compounds 24 and 26 induced autophagic puncta and mediated the autophagic marker LC3-II conversion in HEK293 cells.

Discovery of novel pyrazole derivatives as a potent anti-inflammatory agent in RAW264.7 cells via inhibition of NF-ĸB for possible benefit against SARS-CoV-2.

Due to unavailability of a specific drug/vaccine to attenuate severe acute respiratory syndrome coronavirus 2, the current strategy to combat the infection has been largely dependent upon the use of anti‐inflammatory drugs to control cytokines storm responsible for respiratory depression. Thus, in this study, we discovered novel pyrazole analogs as a potent nuclear factor kappa B (NF‐ĸB) inhibitor. The compounds were assessed for NF‐ĸB transcriptional inhibitory activity in RAW264.7 cells after stimulation with lipopolysaccharides (LPS), revealing Compound 6c as the most potent analog among the tested series. The effect of Compound 6c was further investigated on the levels of interleukin‐1β, tumor necrosis factor‐α, and interleukin‐6 in LPS‐stimulated RAW267.4 cells by enzyme immunoassay, where it causes a significant reduction in the level of these cytokines. In Western blot analysis, Compound 6c also causes the inhibition of inhibitor kappa B‐α and NF‐κB. It was found to be snugly fitted into the inner grove of the active site of NF‐ĸB by forming H‐bonds and a nonbonded interaction with Asn28 in a docking analysis.

MabZIP74 interacts with MaMAPK11-3 to regulate the transcription of MaACO1/4 during banana fruit ripening

Fruit ripening is an economically important process of many edible fruits, which is controlled by a multi-level regulatory network coordinating the spatio-temporal expression of a large array of genes and/or proteins. In banana, ethylene orchestrates the ripening process, but the regulatory mechanism(s) controlling the expression of genes encoding ethylene biosynthesis-related enzymes is not fully understood. Here, we report the identification and characterization of a basic leucine zipper (bZIP) transcription factor MabZIP74 from banana fruit. Its gradually decreased with the progression of banana fruit ripening, implying a negative role for MabZIP74 in banana fruit ripening. MabZIP74 is localized in the nucleus and displays transcriptional inhibitory activity. More specifically, MabZIP74 was found to be a transcriptional repressor of ethylene biosynthetic genes MaACO1 and MaACO4, the accumulation of which paralleled ethylene production during banana ripening. Importantly, a protein kinase MaMAPK11-3 interacted with and phosphorylated MabZIP74, which attenuated MabZIP74-mediated transcriptional repression of MaACO1 and MaACO4 during ripening. Taken together, our findings reveal a novel MabZIP74-mediated regulatory network involved in ethylene biosynthesis and fruit ripening in banana. These results advance our knowledge on fruit ripening and provide additional opportunities for genetic improvement of banana fruit ripening.

Targeting Super-Enhancer-Associated Oncogenes in Osteosarcoma with THZ2, a Covalent CDK7 Inhibitor.

Malignancy of cancer cells depends on the active transcription of tumor-associated genes. Recently, unique clusters of transcriptional enhancers, termed super-enhancers, have been reported to drive the expression of genes that define cell identity. In this study, we characterized specific super-enhancer-associated genes of osteosarcoma, and explored their potential therapeutic value. Super-enhancer regions were characterized through chromatin immunoprecipitation sequencing (ChIP-seq). RT-qPCR was used to detect the mRNA level of CDK7 in patient specimens and confirm the regulation of sensitive oncogenes by THZ2. The phosphorylation of the initiation-associated sites of RNA polymerase II (RNAPII) C-terminal repeat domain (CTD) was measured using Western blotting. Microarray expression analysis was conducted to explore transcriptional changes after THZ2 treatment. A variety of in vitro and in vivo assays were performed to assess the effects of CDK7 knockdown and THZ2 treatment in osteosarcoma. Super-enhancers were associated with oncogenic transcripts and key genes encoding cell-type-specific transcription factors in osteosarcoma. Knockdown of transcription factor CDK7 reduced phosphorylation of the RNAPII CTD, and suppressed the growth and metastasis of osteosarcoma. A new specific CDK7 inhibitor, THZ2, suppressed cancer biology by inhibition of transcriptional activity. Compared with typical enhancers, osteosarcoma super-enhancer-associated oncogenes were particular vulnerable to this transcriptional disruption. THZ2 exhibited a powerful anti-osteosarcoma effect in vitro and in vivo. Super-enhancer-associated genes contribute to the malignant potential of osteosarcoma, and selectively targeting super-enhancer-associated oncogenes with the specific CDK7 inhibitor THZ2 might be a promising therapeutic strategy for patients with osteosarcoma.

Organic acid conjugated phenolic compounds of hardy kiwifruit (Actinidia arguta) and their NF-κB inhibitory activity

Nine new compounds, argutinosides A-I (1–9) together with 20 known compounds (10–29), were isolated from the fruits of Actinidia arguta. Using spectral analysis, the structures of the isolated compounds were identified as 10 succinic acid derivatives, 11 quinic acid derivatives, two shikimic acid derivatives and six citric acid derivatives. The NF-κB transcriptional inhibitory activity of the compounds was evaluated using RAW 264.7 macrophages cells induced by lipopolysaccharide. Among four groups of different organic acid derivatives, the quinic acid derivatives inhibited NF-κB transcriptional activity with an IC50 value of 4.0 μM. Fruit is rich in organic acid and secondary metabolites, which differ depending on the type of fruit. Our present study showed the presence of various organic acids conjugates including nine new 2-methylsuccinic acid phenolic conjugates in kiwiberry and compared their biological activities. This will contribute to application of kiwiberry and also the diversity of different fruits.

Recent Advances in Understanding FOXN3 in Breast Cancer, and Other Malignancies.

FOXN3 (forkhead box N3; CHES1: check point suppressor 1) belongs to the forkhead box (FOX) protein family. FOXN3 displays transcriptional inhibitory activity, and is involved in cell cycle regulation and tumorigenesis. FOXN3 is a tumor suppresser and alterations in FOXN3 are found in of a variety of cancers including melanoma, osteosarcoma, and hepatocellular carcinoma. While the roles of FOXN3 role in some cancers have been explored, its role in breast cancer remains unclear. Here we describe current state of knowledge of FOXN3 functions, and focus on its roles (known and potential) in breast cancer.

Peptides from rice endosperm protein restrain periodontal bone loss in mouse model of periodontitis

ObjectiveFood-derived peptides have been reported to exhibit antibacterial activity against periodontal pathogenic bacteria. However, no effect has been shown on inflammation and bone resorption in periodontal pathology. The overall objective of the current study was to investigate how rice peptides influence biological defense mechanisms against periodontitis-induced inflammatory bone loss, and identify their novel functions as a potential anti-inflammatory drug. DesignThe expression of inflammatory and osteoclast-related molecules was examined in mouse macrophage-derived RAW 264.7 cell cultures using qPCR. Subsequently, the effect of these peptides on inflammatory bone loss in mouse periodontitis was examined using a mouse model of tooth ligation. Briefly, periodontal bone loss was induced for 7 days in mice by ligating the maxillary second molar and leaving the contralateral tooth un-ligated (baseline control). The mice were microinjected daily with the peptide in the gingiva until the day before euthanization. One week after the ligation, TRAP-positive multinucleated cells (MNCs) were enumerated from five random coronal sections of the ligated sites in each mouse. ResultsRice peptides REP9 and REP11 significantly inhibited transcription activity of inflammatory and osteoclast-related molecules. Local treatment with the rice peptides, in mice subjected to ligature-induced periodontitis, inhibited inflammatory bone loss, explaining the decreased numbers of osteoclasts in bone tissue sections. ConclusionTherefore, these data suggested that the rice peptides possess a protective effect against periodontitis.

Abstract 5474: Activity of the S1P pathway promotes ovarian cancer and serves as a novel metabolic target of metformin

Abstract Sphingosine-1-phosphate (S1P), a metabolite of the phospholipid sphingosine, is a bioactive lipid that directly interacts with specific G-protein-coupled receptors to transduce signals that regulate growth, proliferation and motility. Sphingosine kinases (SPHK1 and 2) catalyze the formation of S1P from sphingosine, thereby regulating S1P homeostasis and the sphingolipid rheostat. Recently, using TCGA data, we noted SPHK1 amplification in several gynecologic cancers and that high expression of SPHK1 was associated with increased mortality in high-grade serous ovarian cancer (HGSOC). The findings reported here show that exposure of HGSOC tumor cells to exogenous S1P, or overexpression of SPHK1, induced migration, proliferation and clonogenecity in multiple ovarian cancer cell lines in vitro. Likewise, in a xenograft mouse model of ovarian cancer, overexpression of SPHK1 markedly enhanced tumor growth. In prior pre-clinical studies, we have demonstrated a strong protective effect of the diabetes medication metformin in ovarian cancer. Interestingly, we found that patients with HGSOC that use metformin for diabetes have reduced serum S1P levels compared to controls, suggesting that the sphingolipid rheostat may be a novel metabolic target of metformin in ovarian cancer. Supporting this, we identified that SPHK1 expression in ovarian cancer cell lines is reduced by treatment with metformin, and further that the reduction of SPHK1 by metformin was mediated through inhibition of transcriptional activity of hypoxia-inducible factors (HIF1α and HIF2α). Finally, we show that overexpression of SPHK1 in HGSOC cell lines enhanced the cytotoxic effects of metformin. Taken together, our data indicates that hypoxia-induced SPHK1 expression and downstream S1P signaling promote tumor progression in HGSOC, and that tumors utilizing this pathway may be particularly vulnerable to the anti-cancer effects of metformin. Citation Format: Peter C. Hart, Tatsuyuki Chiyoda, Marion Curtis, Xiaojing Liu, Chun-Yi Chiang, Stephanie McGregor, Ricardo Lastra, Jason Locasale, Ernst Lengyel, Iris L. Romero. Activity of the S1P pathway promotes ovarian cancer and serves as a novel metabolic target of metformin [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5474.

1051 Pharmacological profile of TEI-R1, an oral inverse agonist of RORγt as a drug candidate for psoriasis

Psoriasis is a chronic inflammatory skin disease which was characterized by epidermal hyperplasia and inflammatory cell infiltration in the skin lesion. Recently, many studies have revealed the involvement of IL-17A in the pathogenesis of psoriasis. In fact, IL-17A blockade therapy successfully improved skin lesions in patients with moderate-to-severe psoriasis. Production of IL-17A is regulated by retinoic acid receptor-related orphan nuclear receptor gamma t (RORγt). RORγt is a master transcription factor of IL-17A and other genes related to psoriasis pathogenesis including IL-17F, IL-22 and IL-23R. Therefore, RORγt is expected to be a promising therapeutic target for psoriasis. Although drug discovery and development of RORγt modulators have been in progress by many pharmaceutical companies, drug-like compounds are hard to discover due to its large hydrophobic ligand binding domain. Here, we describe TEI-R1, a novel oral inverse agonist of RORγt. In cell-based reporter gene assay, TEI-R1 inhibited transcription activity of human RORγ (IC50: 18 nM), with little inhibition on RORα (IC50: 4,266 nM). TEI-R1 inhibited the IL-17A production in murine CD4+ T cells (IC50: 28 nM) and human whole blood (IC50: 64 nM). Single oral administration of TEI-R1 to mice significantly decreased plasma IL-17A concentration at 10 mg/kg dose. Finally, efficacy of TEI-R1 was evaluated in imiquimod-induced mouse psoriasis model. Daily oral administration of TEI-R1 for 7 days significantly inhibited back skin epidermal swelling at 30 mg/kg dose. Gene expression of IL-17A, IL-17F, IL-22 and IL-23R in skin biopsies was decreased by TEI-R1 administration. Taken together, our results suggest that TEI-R1 is an orally available potent RORγt inverse agonist and that it could offer an alternative to IL-17A blockade therapy for psoriasis patients.