Glycoprotein 90K Promotes E-Cadherin Degradation in a Cell Density-Dependent Manner via Dissociation of E-Cadherin-p120-Catenin Complex

Glycoprotein 90K (also known as LGALS3BP or Mac-2BP) is a tumor-associated protein, and high 90K levels are associated with poor prognosis in some cancers. To clarify the role of 90K as an indicator for poor prognosis and metastasis in epithelial cancers, the present study investigated the effect of 90K on an adherens junctional protein, E-cadherin, which is frequently absent or downregulated in human epithelial cancers. Treatment of certain cancer cells with 90K significantly reduced E-cadherin levels in a cell-population-dependent manner, and these cells showed decreases in cell adhesion and increases in invasive cell motility. Mechanistically, 90K-induced E-cadherin downregulation occurred via ubiquitination-mediated proteasomal degradation. 90K interacted with the E-cadherin–p120-catenin complex and induced its dissociation, altering the phosphorylation status of p120-catenin, whereas it did not associate with β-catenin. In subconfluent cells, 90K decreased membrane-localized p120-catenin and the membrane fraction of the p120-catenin. Particularly, 90K-induced E-cadherin downregulation was diminished in p120-catenin knocked-down cells. Taken together, 90K upregulation promotes the dissociation of the E-cadherin–p120-catenin complex, leading to E-cadherin proteasomal degradation, and thereby destabilizing adherens junctions in less confluent tumor cells. Our results provide a potential mechanism to explain the poor prognosis of cancer patients with high serum 90K levels.

Added Value from Secondary Use of Person Generated Health Data in Consumer Health Informatics

Introduction: Various health-related data, subsequently called Person Generated Health Data (PGHD), is being collected by patients or presumably healthy individuals as well as about them as much as they become available as measurable properties in their work, home, and other environments. Despite that such data was originally just collected and used for dedicated predefined purposes, more recently it is regarded as untapped resources that call for secondary use. Method: Since the secondary use of PGHD is still at its early evolving stage, we have chosen, in this paper, to produce an outline of best practices, as opposed to a systematic review. To this end, we identified key directions of secondary use and invited protagonists of each of these directions to present their takes on the primary and secondary use of PGHD in their sub-fields. We then put secondary use in a wider perspective of overarching themes such as privacy, interpretability, interoperability, utility, and ethics. Results: We present the primary and secondary use of PGHD in four focus areas: (1) making sense of PGHD in augmented Shared Care Plans for care coordination across multiple conditions; (2) making sense of PGHD from patient-held sensors to inform cancer care; (3) fitting situational use of PGHD to evaluate personal informatics tools in adaptive concurrent trials; (4) making sense of environment risk exposure data in an integrated context with clinical and omics-data for biomedical research. Discussion: Fast technological progress in all the four focus areas calls for a societal debate and decision-making process on a multitude of challenges: how emerging or foreseeable results transform privacy; how new data modalities can be interpreted in light of clinical data and vice versa; how the sheer mass and partially abstract mathematical properties of the achieved insights can be interpreted to a broad public and can consequently facilitate the development of patient-centered services; and how the remaining risks and uncertainties can be evaluated against new benefits. This paper is an initial summary of the status quo of the challenges and proposals that address these issues. The opportunities and barriers identified can serve as action items individuals can bring to their organizations when facing challenges to add value from the secondary use of patient-generated health data.

Bromopropane Compounds Increase the Stemness of Colorectal Cancer Cells

Bromopropane (BP) compounds, including 1-bromopropane, 2-bromopropane, and 1,2-dibromopropane, are used in industry for various purposes, and their deleterious effects on human health are becoming known. In this study, we examined the effects of BP compounds on the stemness of colorectal cancer cells. At low, non-cytotoxic concentrations, BP compounds significantly increased spheroid formation in CSC221, DLD1, Caco2, and HT29 cells. In addition, the levels of cancer stem cell markers, such as aldehyde dehydrogenase-1, cluster of differentiation 133 (CD133), CD44, Lgr5, Musashi-1, Ephrin receptor, and Bmi-1 increased after exposure to BP compounds. BP compounds increased the transcriptional activity of the TOPflash and glioma-associated oncogene homolog zinc finger protein (Gli) promoters in reporter assays and increased the expression of Gli-1, Gli-2, Smoothened (SMO), and β-catenin by RT-PCR. These results demonstrate for the first time that BP compounds have the potential to promote cancer stemness.

The lichen secondary metabolite atranorin suppresses lung cancer cell motility and tumorigenesis

Lichens are symbiotic organisms that produce various secondary metabolites. Here, different lichen extracts were examined to identify secondary metabolites with anti-migratory activity against human lung cancer cells. Everniastrum vexans had the most potent inhibitory activity, and atranorin was identified as an active subcomponent of this extract. Atranorin suppressed β-catenin-mediated TOPFLASH activity by inhibiting the nuclear import of β-catenin and downregulating β-catenin/LEF and c-jun/AP-1 downstream target genes such as CD44, cyclin-D1 and c-myc. Atranorin decreased KAI1 C-terminal interacting tetraspanin (KITENIN)-mediated AP-1 activity and the activity of the KITENIN 3′-untranslated region. The nuclear distribution of the AP-1 transcriptional factor, including c-jun and c-fos, was suppressed in atranorin-treated cells, and atranorin inhibited the activity of Rho GTPases including Rac1, Cdc42, and RhoA, whereas it had no effect on epithelial-mesenchymal transition markers. STAT-luciferase activity and nuclear STAT levels were decreased, whereas total STAT levels were moderately reduced. The human cell motility and lung cancer RT² Profiler PCR Arrays identified additional atranorin target genes. Atranorin significantly inhibited tumorigenesis in vitro and in vivo. Taken together, our results indicated that E. vexans and its subcomponent atranorin may inhibit lung cancer cell motility and tumorigenesis by affecting AP-1, Wnt, and STAT signaling and suppressing RhoGTPase activity.

MAP2K1 Mutation in Colorectal Cancer Patients: Therapeutic Challenge Using Patient-Derived Tumor Cell Lines

BACKGROUND: The MAP2K1 K57T mutation is known to be a potential mechanism of primary and secondary resistance to EGFR inhibitors in metastatic colorectal cancer (CRC) and has also been reported to promote resistance to BRAF and MEK inhibitors. It is important to overcome therapeutic resistance to EGFR inhibitors to improve the treatment outcomes of metastatic CRC. METHODS: We established patient-derived tumor cells (PDCs) from metastatic lesions that newly appeared during treatment with a BRAF inhibitor (LGX-818) plus an EGFR inhibitor (cetuximab) in a patient with BRAF-mutant CRC. To investigate therapeutic options to overcome acquired resistance due to MAP2K1 mutation in BRAF-mutant CRC, we performed cell viability assays using the PDCs. RESULTS: We tested whether the PDCs were resistant to an EGFR inhibitor (cetuximab) and a BRAF inhibitor (sorafenib) as these cells were established at the time of resistance to the EGFR plus BRAF inhibitors. Moreover, the anti-tumor effect of AZD6244 (MEK inhibitor) was evaluated because PDCs harbored a MAP2K1 mutation at the time of resistance to the EGFR plus BRAF inhibitors. MTT proliferation assays showed that monotherapy with cetuximab, sorafenib, or AZD6244 did not suppress cell viability. We next tested viability of the PDCs to combination treatment with cetuximab plus AZD6244 and sorafenib plus AZD6244. Proliferation of PDCs was significantly inhibited by sorafenib and AZD6244, but not by cetuximab plus AZD6244. Investigation of the combined effect of sorafenib and AZD6244 using the calculated combination index (CI) showed synergistic effects of sorafenib and AZD6244 in combination therapy applied to PDCs with the MAP2K1 K57T mutation. CONCLUSION: Our results suggest that combination treatment with BRAF and MEK inhibitors might be a novel treatment strategy for MAP2K1 K57T-mutant CRC. This finding will be helpful to guide treatment of patients with CRC that is resistant to EGFR inhibitors.

Abstract 3530: KITENIN works as a fine regulator of ErbB4 expression in colorectal cancer tissues in addition to E3-ubiquitin ligase Nrdp1

Purpose: Understanding the complex biological functions of E3-ubiquitin ligases may facilitate the modulation of E3-ubiquitin ligases as a promising approach for the development of novel anticancer drugs. We recently identified that the KITENIN/ErbB4-Dvl2-c-Jun axis works as a novel unconventional downstream signal of epidermal growth factor in colorectal cancer (CRC) tissues and that the immunohistochemical expression of KITENIN/ErbB4 was highly expressed in tumor tissues from advanced CRC stage. However, the detailed mechanisms that explain the higher levels of ErbB4 in colon cancer tissues are largely unknown. Here we investigated whether E3-ubiquitin ligases participate in the operation of the KITENIN/ErbB4-Dvl2-c-Jun axis and in the maintenance of elevated KITENIN/ErbB4 complex in CRC.

Results & Discussion: We found that Nrdp1, an E3-ligase for ErbB3/ErbB4, interacted with KITENIN (KAI1 C-terminal interacting tetraspanin) to form a functional KITENIN/ErbB4/Nrdp1 complex and is responsible for down-regulating Dvl2 within this complex. Interestingly, ErbB4 was resistant to degradation by Nrdp1 in KITENIN/Nrdp1-co-transfected CRC cells, and KITENIN bound to the C-terminal coiled-coil domain of Nrdp1. Chemical blockade of ErbB kinase did not block the action of EGF to increase in total/phospho-ErbB4 and phospho-ERK in KITENIN/ErbB4-cotransfected cells, whereas it blocked the action of EGF in ErbB4 alone-transfected CRC cells. In human CRC tissues, higher expressions of ErbB4 and KITENIN and lower expression of Dvl2 was observed in stage IV samples than in stage I, but a low level of Nrdp1 was expressed in both stages and it did not differ significantly by stage. These results indicated that Nrdp1 is necessary for the reduction in Dvl2 to generate c-Jun in the EGF-KITENIN/ErbB4-c-Jun axis, but more importantly, elevated KITENIN protects KITENIN-bound ErbB4 from Nrdp1-mediated degradation via physical collaboration between the KITENIN/ErbB4 complex and Nrdp1, but not via modulation of ErbB kinase activity. Thus, KITENIN functions in the maintenance of a higher expression level of ErbB4 in advanced CRC tissues, independent of ubiquitin-mediated degradation via Nrdp1.

Conclusion: Our present findings add a new component to our understanding of the molecular events underlying the regulation of ErbB4 expression level in CRC tissues: KITENIN is also a fine regulator of ErbB4 expression in addition to E3-ubiquitin ligase Nrdp1.

Citation Format: Jeong A Bae, Eun Gene Sun, Yoo-Seung Ko, Hui Jeong Choi, Chaeyong Jung, Kyung-Hwa Lee, Ik Joo Chung, Kyung-Sub Moon, Young Hyun Yu, Hyung-Ho Ha, Hangun Kim, Kyung Keun Kim. KITENIN works as a fine regulator of ErbB4 expression in colorectal cancer tissues in addition to E3-ubiquitin ligase Nrdp1 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3530. doi:10.1158/1538-7445.AM2017-3530

Abstract 1589: Zinc inhibits androgen receptor expression to inhibit prostate cancer cell growth

Background: Prostate gland contains high level of intracellular zinc which is dramatically diminished during cancer development. Due to the obscure role of zinc in this process, therapeutic application using zinc and its supplement is very limited. This study aims to clarify the role(s) of zinc and its intervening mechanism.

Material and methods: Treated by zinc chloride (15-150 µM), several prostate cancer cell lines were applied to confocal microscopy for intracellular trafficking of exogenous zinc, in vitro proliferation assays for their growth, prostate specific antigen (PSA)-based reporter-mediated transactivation, and Western blot for detection of androgen receptor (AR), PSA and ubiquitination. Further in vivo studies were performed to demonstrate the effect of zinc (10-20 mg/kg) on xenograft cancer growth using syngeneic animals followed by tumor analyses.

Results: Zinc chloride suppressed androgen-dependent proliferation of human prostate cancer cells and accordingly zinc chloride dramatically inhibited androgen-mediated transactivation and several androgen target protein expressions, including PSA and p21. Further investigation showed that addition of zinc chloride strikingly downregulated AR protein levels after 4 hours up to 24 hours in both human LNCaP and murine TRAMP C2 prostate cancer cell lines. AR downregulation resulted from facilitated protein degradation instead of transcriptional control. Further in vivo study was carried out using syngeneic mice bearing C2 subcutaneous tumors. Peritoneal injection of zinc chloride significantly reduced tumor size. Analysis of these tumors revealed that there were reduced expression of AR and increased cell death.

Conclusions: Zinc has been shown to inhibit incumbent oncogenic NF-κB pathway. These results also suggest that intracellular zinc inhibits cell growth via downregulation of AR to inhibit growth of prostate cancer. Considering that AR functions as a major effector in prostate cancer development and progression into castration resistant prostate cancer, loss of zinc may be a critical step for this devastating disease and further studies can be performed to develop zinc-based cancer therapeutics.

Citation Format: Phuong Kim To, Young-Suk Cho, Se-Young Kwon, Taek Won Kang, Kyung Keun Kim, Chaeyong Jung. Zinc inhibits androgen receptor expression to inhibit prostate cancer cell growth [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1589. doi:10.1158/1538-7445.AM2017-1589

Abstract 4209: Inhibitory activity of lichen secondary metabolite, physciosporin, against lung cancer cell motility

Lichens produce various unique chemicals that can be used for pharmaceutical purposes. To screen for novel lichen secondary metabolites showing inhibitory activity against lung cancer cell motility, we tested acetone extracts of 13 lichen samples collected in Chile. Physciosporin, isolated from Pseudocyphellaria coriacea (Hook f. & Taylor) D.J. Galloway & P. James, was identified as an effective compound and showed significant inhibitory activity in migration and invasion assays against human lung cancer cells. Physciosporin treatment reduced both protein and mRNA levels of N-cadherin with concomitant decreases in the levels of epithelial-mesenchymal transition markers such as snail and twist. Physciosporin also suppressed KITENIN (KAI1 C-terminal interacting tetraspanin)-mediated AP-1 activity in both the absence and presence of epidermal growth factor stimulation. Quantitative real-time PCR analysis showed that the expression of the metastasis suppressor gene, KAI1, was increased while that of the metastasis enhancer gene, KITENIN, was dramatically decreased by physciosporin. Particularly, the activity of 3'-untranslated region of KITENIN was decreased by physciosporin. Moreover, Cdc42 and Rac1 activities were decreased by physciosporin. These results demonstrated that the lichen secondary metabolite, physciosporin, inhibits lung cancer cell motility through novel mechanisms of action.

Citation Format: Yi Yang, Young Hyun Yu, Hyung-Ho Ha, Kyung-Hwa Lee, Kyung-Sub Moon, Kyung Keun Kim, Hangun Kim. Inhibitory activity of lichen secondary metabolite, physciosporin, against lung cancer cell motility [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4209. doi:10.1158/1538-7445.AM2017-4209

Obesity: a chronic relapsing progressive disease process. A position statement of the World Obesity Federation

This paper considers the argument for obesity as a chronic relapsing disease process. Obesity is viewed from an epidemiological model, with an agent affecting the host and producing disease. Food is the primary agent, particularly foods that are high in energy density such as fat, or in sugar-sweetened beverages. An abundance of food, low physical activity and several other environmental factors interact with the genetic susceptibility of the host to produce positive energy balance. The majority of this excess energy is stored as fat in enlarged, and often more numerous fat cells, but some lipid may infiltrate other organs such as the liver (ectopic fat). The enlarged fat cells and ectopic fat produce and secrete a variety of metabolic, hormonal and inflammatory products that produce damage in organs such as the arteries, heart, liver, muscle and pancreas. The magnitude of the obesity and its adverse effects in individuals may relate to the virulence or toxicity of the environment and its interaction with the host. Thus, obesity fits the epidemiological model of a disease process except that the toxic or pathological agent is food rather than a microbe. Reversing obesity will prevent most of its detrimental effects.

Living Donor Liver Transplantation in a Patient With Extensive Portomesenteric Venous Thrombosis: Case Report

Extensive portomesenteric venous thrombus preventing restoration of adequate portal venous flow used to be considered a contraindication to liver transplantation. The subject was a 49-year-old male with hepatitis B cirrhosis and extensive thrombosis of portal, splenic, and superior mesenteric veins, and two large collateral vessels; one dilated and tortuous inferior to the pancreaticoduodenal vein and relevant to splanchnic venous return and the other a dilated coronary vein relevant to splenic venous return. During operation, the portal vein was anastomosed to these large collateral vessels using cryopreserved iliac vein. In conclusion, portal reconstruction with large collateral vessels in living-donor liver transplantation could be used selectively for patients with extensive portomesenteric venous thrombosis.

KITENIN functions as a fine regulator of ErbB4 expression level in colorectal cancer via protection of ErbB4 from E3-ligase Nrdp1-mediated degradation

Understanding the complex biological functions of E3-ubiquitin ligases may facilitate the development of mechanism-based anti-cancer drugs. We recently identified that the KITENIN/ErbB4-Dvl2-c-Jun axis works as a novel unconventional downstream signal of epidermal growth factor (EGF) in colorectal cancer (CRC) tissues. Here we addressed whether E3-ubiquitin ligases are required for operation of this axis. We found that Nrdp1, an E3-ligase for ErbB3/ErbB4, interacted with KITENIN (KAI1 C-terminal interacting tetraspanin) to form a functional KITENIN/ErbB4/Nrdp1 complex and is responsible for down-regulating Dvl2 within this complex. Interestingly, ErbB4 was resistant to degradation by Nrdp1 in KITENIN/Nrdp1-co-transfected CRC cells, and KITENIN bound to the C-terminal coiled-coil domain of Nrdp1. Chemical blockade of ErbB kinase did not block the action of EGF to increase in total/phospho-ErbB4 and phospho-ERK in KITENIN/ErbB4-cotransfected cells, whereas it blocked the action of EGF in ErbB4 alone-transfected CRC cells. In human CRC tissues, higher expressions of ErbB4 and KITENIN and lower expression of Dvl2 was observed in stage IV samples than in stage I, but a low level of Nrdp1 was expressed in both stages and it did not differ significantly by stage. These results indicated that Nrdp1 is necessary for the reduction in Dvl2 to generate c-Jun in the EGF-KITENIN/ErbB4-c-Jun axis, but more importantly, elevated KITENIN protects KITENIN-bound ErbB4 from Nrdp1-mediated degradation via physical collaboration between the KITENIN/ErbB4 complex and Nrdp1, but not via modulation of ErbB kinase activity. Thus, KITENIN functions in the maintenance of a higher expression level of ErbB4 in advanced CRC tissues, independent of ubiquitin-mediated degradation via Nrdp1. © 2016 Wiley Periodicals, Inc.

90K Glycoprotein Promotes Degradation of Mutant β-Catenin Lacking the ISGylation or Phosphorylation Sites in the N-terminus

β-Catenin is a major transducer of the Wnt signaling pathway, which is aberrantly expressed in colorectal and other cancers. Previously, we showed that β-catenin is downregulated by the 90K glycoprotein via ISGylation-dependent degradation. However, the further mechanisms of β-catenin degradation by 90K-mediated ISGylation pathway were not investigated. This study aimed to identify the β-catenin domain responsible for the action of 90K and to compare the mechanism of 90K on β-catenin degradation with phosphorylation-dependent ubiquitinational degradation of β-catenin. The deletion mutants of β-catenin lacking N- or C-terminal domain or mutating the N-terminal lysine or nonlysine residue were employed to delineate the characteristics of β-catenin degradation by 90K-mediated ISGylation pathway. 90K induced Herc5 and ISG15 expression and reduced β-catenin levels in HeLa and CSC221 cells. The N-terminus of β-catenin is required for 90K-induced β-catenin degradation, but the N-terminus of β-catenin is not essential for interaction with Herc5. However, substituting lysine residues in the N-terminus of β-catenin with arginine or deleting serine or threonine residue containing domains from the N-terminus does not affect 90K-induced β-catenin degradation, indicating that the N-terminal 86 amino acids of β-catenin are crucial for 90K-mediated ISGylation/degradation of β-catenin in which the responsible lysine or nonlysine residues were not identified. Our present results highlight the action of 90K on promoting degradation of mutant β-catenin lacking the phosphorylation sites in the N-terminus. It provides further insights into the discrete pathway downregulating the stabilized β-catenin via acquiring mutations at the serine/threonine residues in the N-terminus.

Docosahexaenoic Acid Inhibits Tumor Promoter-Induced Urokinase-Type Plasminogen Activator Receptor by Suppressing PKCδ- and MAPKs-Mediated Pathways in ECV304 Human Endothelial Cells

The overexpression of urokinase-type plasminogen activator receptor (uPAR) is associated with inflammation and virtually all human cancers. Despite the fact that docosahexaenoic acid (DHA) has been reported to possess anti-inflammatory and anti-tumor properties, the negative regulation of uPAR by DHA is still undefined. Here, we investigated the effect of DHA on 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced uPAR expression and the underlying molecular mechanisms in ECV304 human endothelial cells. DHA concentration-dependently inhibited TPA-induced uPAR. Specific inhibitors and mutagenesis studies showed that PKCδ, JNK1/2, Erk1/2, NF-κB, and AP-1 were critical for TPA-induced uPAR expression. Application of DHA suppressed TPA-induced translocation of PKCδ, activation of the JNK1/2 and Erk1/2 signaling pathways, and subsequent AP-1 and NF-κB transactivation. In conclusion, these observations suggest a novel role for DHA in reducing uPAR expression and cell invasion by inhibition of PKCδ, JNK1/2, and Erk1/2, and the reduction of AP-1 and NF-κB activation in ECV304 human endothelial cells.

Geijigajakyak decoction inhibits the motility and tumorigenesis of colorectal cancer cells

Background

Recent studies report that inflammatory diseases of the large intestine are associated with colorectal cancer. Geijigajakyak Decoction (GJD) has antispasmodic and anti-inflammatory effects on the gastrointestinal tract. Thus, in light of the connection between chronic bowel inflammation and colorectal cancer (CRC), we asked whether GJD inhibits colorectal tumorigenesis.

Methods

The effects of GJD on the viability and proliferation of CRC cells were evaluated using MTT and BrdU assays, respectively. The motility of CRC cells was examined by a Transwell migration/invasion assay and immunoblot analysis was used to examine the signaling pathways associated with migration. A syngeneic Balb/c mice allograft model, in which CT26 cells were injected into the dorsum, was used to evaluate the anti-tumor effects of GJD in vivo.

Results

GJD had no cytotoxic effects against HCT116 CRC cells, although it did inhibit their proliferation. GJD inhibited the migration of HCT116 cells, and suppressed the invasion of HCT116, Caco2, and CSC221 CRC cells. In addition, GJD downregulated the expression of p-JNK and p-p38 MAPK, which are downstream signaling molecules associated with invasiveness. Furthermore, oral administration of GJD (333 mg/kg, twice a day) inhibited tumor growth in a mouse xenograft model.

Conclusions

GJD inhibited the motility of human CRC cells and suppressed tumorigenesis in a mouse model. These results suggest that GJD warrants further study as a potential adjuvant anti-cancer therapy.

Electronic supplementary material

The online version of this article (doi:10.1186/s12906-016-1281-z) contains supplementary material, which is available to authorized users.

Prostaglandin E2 stimulates urokinase-type plasminogen activator receptor via EP2 receptor-dependent signaling pathways in human AGS gastric cancer cells

Aberrant expression of urokinase-type plasminogen activator receptor (uPAR) has been observed in human gastric cancers. Prostaglandin E₂ (PGE₂ ), whose biosynthesis is catalyzed by cyclooxygenase-2 (COX-2), is implicated in cancer metastasis; however, the cellular and molecular mechanisms of PGE₂ -driven uPAR expression are yet to be elucidated in human gastric cancer AGS cells. In this study, we showed that PGE₂ induces uPAR expression in concentration- and time-dependent manners. Furthermore, using antagonists and siRNA, we found that among the four subtypes of PGE₂ receptors, EP2 receptors are involved in PGE₂ -induced uPAR expression. PGE₂ induced the activation of Src, epidermal growth factor receptor (EGFR), c-Jun NH₂ -terminal kinase (JNK), extracellular signal-regulated kinase (Erk), and p38 mitogen activated protein kinase (p38 MAPK). Specific inhibitor and mutagenesis studies showed that Src, EGFR, JNK1/2, and Erk1/2 are involved in PGE₂ -induced uPAR expression. PGE₂ induces EP2-dependent phosphorylation of Src, while the activation of Src-dependent EGFR leads to the phosphorylation of JNK1/2 and Erk1/2. Deletion and site-directed mutagenesis studies demonstrated the involvement of transcription factor activator protein (AP)-1 and nuclear factor-kappa B (NF-κB) in PGE₂ -induced uPAR expression. EGFR-dependent MAPKs (JNK1/2 and Erk1/2) function as the upstream signaling molecules in the activation of AP-1 and NF-κB, respectively. AGS cells pre-treated with PGE₂ showed remarkably enhanced invasiveness, which was partially abrogated by uPAR-neutralizing antibodies. To the best of our knowledge, this is the first report that PGE₂ -induced uPAR expression, which stimulates invasiveness of human gastric cancer AGS cells, is mediated by the EP2 receptor-dependent Src/EGFR/JNK1/2, Erk1/2/AP-1, and Src/EGFR/JNK1/2, Erk1/2/NF-κB cascades. © 2016 Wiley Periodicals, Inc.

Abstract 4477: Loss of EZH2 accelerates STAT5 loss mediated fatty liver and cancer development through non-methyltransferase function

Background: The molecular mechanisms underlying the development of fatty liver and hepatocellular carcinoma are not fully understood. Loss of STAT5 from liver tissue results in hepatosteatosis and hepatocellular carcinoma (HCC). Enhancer of zeste homolog 2 (EZH2) mediates epigenetic silencing of gene expression and is frequently up-regulated in human HCC. STAT5 recruits EZH2, which represses a substantial subset of genes regulated by STAT5 during B lymphopoiesis. However, it is not clear if EZH2 can affect STAT5-target genes in liver.

Methods: To investigate the role of STAT5 and EZH2 in liver, mice were generated that carried EZH2fl/fl alleles, STAT5fl/fl alleles, EZH2fl/flSTAT5fl/fl alleles and an Alb-Cre transgene. Lipid analysis in serum and liver, and RNA-seq were examined at 3 & 8 months of age. Mice were also examined by chronic 3 months injection by carbon tetrachloride (CCl4).

Results: The deletion of STAT5 in hepatocyte caused fatty liver and increased cholesterol in serum and liver. The deletion of EZH2 did not make a difference in H3K27me3 expression, and lipid in serum and liver. However, combined loss of EZH2 and STAT5 caused severe fatty liver, increase triglyceride and the ratio liver/body weight compare to STAT5 KO mice (the ratio; 0.097 vs. 0.058, p < 0.05). In response to 3 months treatment with CCl4, combined loss of EZH2 and STAT5 showed accelerated development of hepatocellular carcinoma at 12 months of age. Transcriptome analysis identified the expression of several genes was significantly increased (cd36, pparγ, cyp4a14, lipoprotein lipase, fasn) and decreased (nox4, bbc3, bcl2l1, cdkn2b) which were well known as STAT5 target genes in combined loss of EZH2 and STAT5.

Conclusions: This work demonstrates that loss of EZH2 in liver affects the expression of STAT5 target genes and accelerates STAT5 loss mediated fatty liver and hepatocellular carcinoma development through non-methyltransferase function.

Citation Format: Woo Kyun Bae, Hyun Jeong Shim, Sang Hee Cho, Ik-Joo Chung, Kyung Keun Kim. Loss of EZH2 accelerates STAT5 loss mediated fatty liver and cancer development through non-methyltransferase function. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4477.

[CHANGES IN BRAIN ELECTRICAL ACTIVITY PATTERNS IN RATS WITH DIFFERENT SUSCEPTIBILITY TO SEIZURES IN LITHIUM-PILOCARPINE MODEL OF STATUS EPILEPTICUS]

The intracranial EEG was continuously registered in Krushinskii-Molodkina rats with inherited susceptibility to audiogenic seizures and in Wistar rats, which are resistant to the audiogenic convulsions in the lithium-pilocarpine model of status epilepticus (SE). The recordings were done from somatosensory, auditory and visual cortical areas, caudate nucleus, hippocampus and dorso-medial nucleus of thalamus. We found that SE was induced in Krushinskii-Molodkina rats by intramuscular injections of pilocarpine at a minimum dose of 15 mg/kg, while in Wistar rats with a dose of 25 mg/kg. We describe six successive EEG patterns during SE. We identified behavioral convulsive manifestations associated with each phase of the SE. Rats of both strains had the same sequence and the main properties of EEG patterns, except the latency of phase 1 (Krushinskii-Molodkina rats 13 + 3 min vs. Wistar rats 23 + 2 min). In conclusion, the rats with susceptibility to audiogenic seizures have increased sensitivity to the pilocarpine, but the development and time-course of SE in rats of both strains did not differ.

HE4 promotes collateral resistance to cisplatin and paclitaxel in ovarian cancer cells

Background

Chemotherapy resistance presents a difficult challenge in treating epithelial ovarian cancer patients, particularly when tumors exhibit resistance to multiple chemotherapeutic agents. A few studies have shown that elevated serum levels of the ovarian cancer biomarker HE4 correlate with tumor chemoresistance, response to treatment, and survival. Here, we sought to confirm our previous results that HE4 contributes to collateral resistance to cisplatin and paclitaxel in vitro and uncover factors that may contribute to HE4-mediated chemoresistance.

Methods

MTS assays and western blots for cleaved PARP were used to assess resistance of HE4-overexpressing SKOV3 and OVCAR8 clones to cisplatin and paclitaxel. CRISPR/Cas technology was used to knockdown HE4 in HE4-overexpressing SKOV3 cells. A microarray was conducted to determine differential gene expression between SKOV3 null vector-transfected and HE4-overexpressing clones upon cisplatin exposure, and results were validated by quantitative RT-PCR. Regulation of mitogen activated protein kinases (MAPKs) and tubulins were assessed by western blot.

Results

HE4-overexpressing SKOV3 and OVCAR8 clones displayed increased resistance to cisplatin and paclitaxel. Knockdown of HE4 in HE4-overexpressing SKOV3 cells partially reversed chemoresistance. Microarray analysis revealed that HE4 overexpression resulted in suppression of cisplatin-mediated upregulation of EGR1, a MAPK-regulated gene involved in promoting apoptosis. Upregulation of p38, a MAPK activated in response to cisplatin, was suppressed in HE4-overexpressing clones. No differences in extracellular signal-regulated kinase (ERK) activation were noted in HE4-overexpressing clones treated with 25 μM cisplatin, but ERK activation was partially suppressed in HE4-overexpressing clones treated with 80 μM cisplatin. Furthermore, treatment of cells with recombinant HE4 dramatically affected ERK activation in SKOV3 and OVCAR8 wild type cells. Recombinant HE4 also upregulated α-tubulin and β-tubulin levels in SKOV3 and OVCAR8 cells, and microtubule associated protein tau (MAPT) gene expression was increased in SKOV3 HE4-overexpressing clones.

Conclusions

Overexpression of HE4 promotes collateral resistance to cisplatin and paclitaxel, and downregulation of HE4 partially reverses this chemoresistance. Multiple factors could be involved in HE4-mediated chemoresistance, including deregulation of MAPK signaling, as well as alterations in tubulin levels or stability.

Electronic supplementary material

The online version of this article (doi:10.1186/s13048-016-0240-0) contains supplementary material, which is available to authorized users.

Variability in empathic fear response among 11 inbred strains of mice

Empathy is an important emotional process that involves the ability to recognize and share emotions with others. We have previously developed an observational fear learning (OFL) behavioral assay to measure empathic fear in mice. In the OFL task, a mouse is conditioned for context-dependent fear when it observes a conspecific demonstrator receiving aversive stimuli. In the present study, by comparing 11 different inbred mouse strains that are commonly used in the laboratory, we found that empathic fear response was highly variable between different strains. Five strains--C57BL/6J, C57BL/6NTac, 129S1/SvImJ, 129S4/SvJae and BTBR T(+) Itpr3(tf) /J--showed observational fear (OF) responses, whereas AKR/J, BALB/cByJ, C3H/HeJ, DBA/2J, FVB/NJ and NOD/ShiLtJ mice exhibited low empathic fear response. Importantly, day 2 OF memory was significantly correlated with contextual memory in the classical fear conditioning among the 11 strains. Innate differences in anxiety, locomotor activity, sociability and preference for social novelty were not significantly correlated with OFL. Interestingly, early adolescent C57BL/6J mice exhibited an increase in acquisition of OF. The level of OFL in C57BL/6J strain was not affected by sex or strains of the demonstrator. Taken together, these data strongly suggest that there are naturally occurring OFL-specific genetic variations modulating empathic fear behaviors in mice. The identification of causal genes may uncover novel genetic pathways and underlying neural mechanisms that modulate empathic fear and, ultimately, provide new targets for therapeutic intervention in human mental disorders associated with impaired empathy.

Inhibitory Activity of (+)-Usnic Acid against Non-Small Cell Lung Cancer Cell Motility

Lichens are symbiotic organisms that produce various unique chemicals that can be used for pharmaceutical purposes. With the aim of screening new anti-cancer agents that inhibit cancer cell motility, we tested the inhibitory activity of seven lichen species collected from the Romanian Carpathian Mountains against migration and invasion of human lung cancer cells and further investigated the molecular mechanisms underlying their anti-metastatic activity. Among them, Alectoria samentosa, Flavocetraria nivalis, Alectoria ochroleuca, and Usnea florida showed significant inhibitory activity against motility of human lung cancer cells. HPLC results showed that usnic acid is the main compound in these lichens, and (+)-usnic acid showed similar inhibitory activity that crude extract have. Mechanistically, β-catenin-mediated TOPFLASH activity and KITENIN-mediated AP-1 activity were decreased by (+)-usnic acid treatment in a dose-dependent manner. The quantitative real-time PCR data showed that (+)-usnic acid decreased the mRNA level of CD44, Cyclin D1 and c-myc, which are the downstream target genes of both β-catenin/LEF and c-jun/AP-1. Also, Rac1 and RhoA activities were decreased by treatment with (+)-usnic acid. Interestingly, higher inhibitory activity for cell invasion was observed when cells were treated with (+)-usnic acid and cetuximab. These results implied that (+)-usnic acid might have potential activity in inhibition of cancer cell metastasis, and (+)-usnic acid could be used for anti-cancer therapy with a distinct mechanisms of action.

Role of CrkII Signaling in RANKL-Induced Osteoclast Differentiation and Function

Rac1, a member of small GTPases, is a key regulator of osteoclast differentiation and function. The Crk family adaptor proteins, consisting of Src homology (SH) 2 and SH3 protein-binding domains, regulate cell proliferation, migration, and invasion through Rac1 activation. In this study, we examined the role of CrkII in osteoclast differentiation and function. Retroviral overexpression of CrkII in osteoclast precursors enhanced osteoclast differentiation and resorptive function through Rac1 activation. The knockdown of CrkII in osteoclast precursors using small interfering RNA inhibited osteoclast differentiation and its resorption activity. Unlike wild-type CrkII, overexpression of the three SH domains in mutant forms of CrkII did not enhance either osteoclast differentiation or function. Phosphorylation of p130 Crk-associated substrate (p130Cas) by osteoclastogenic cytokines in preosteoclasts increased the interaction between p130Cas and CrkII, which is known to be involved in Rac1 activation. Furthermore, transgenic mice overexpressing CrkII under control of a tartrate-resistant acid phosphatase promoter exhibited a low bone mass phenotype, associated with increased resorptive function of osteoclasts in vivo. Taken together, our data suggest that the p130Cas/CrkII/Rac1 signaling pathway plays an important role in osteoclast differentiation and function, both in vitro and in vivo.

Cadmium induces matrix metalloproteinase-9 expression via ROS-dependent EGFR, NF-кB, and AP-1 pathways in human endothelial cells

Cadmium (Cd), a widespread cumulative pollutant, is a known human carcinogen, associated with inflammation and tumors. Matrix metalloproteinase-9 (MMP-9) plays a pivotal role in tumor metastasis; however, the mechanisms underlying the MMP-9 expression induced by Cd remain obscure in human endothelial cells. Here, Cd elevated MMP-9 expression in dose- and time-dependent manners in human endothelial cells. Cd increased ROS production and the ROS-producing NADPH oxidase. Cd translocates p47(phox), a key subunit of NADPH oxidase, to the cell membrane. Cd also activated the phosphorylation of EGFR, Akt, Erk1/2, and JNK1/2 in addition to promoting NF-кB and AP-1 binding activities. Specific inhibitor and mutagenesis studies showed that EGFR, Akt, Erk1/2, JNK1/2 and transcription factors NF-κB and AP-1 were related to Cd-induced MMP-9 expression in endothelial cells. Akt, Erk1/2, and JNK1/2 functioned as upstream signals in the activation of NF-κB and AP-1, respectively. In addition, N-acetyl-l-cystein (NAC), diphenyleneiodonium chloride (DPI) and apocynin (APO) inhibited the Cd-induced activation of EGFR, Akt, Erk1/2, JNK1/2, and p38 MAPK, indicating that ROS production by NADPH oxidase is the furthest upstream signal in MMP-9 expression. At present, it states that Cd displayed marked invasiveness in ECV304 cells, which was partially abrogated by MMP-9 neutralizing antibodies. These results demonstrated that Cd induces MMP-9 expression via ROS-dependent EGFR->Erk1/2, JNK1/2->AP-1 and EGFR->Akt->NF-κB signaling pathways and, in turn, stimulates invasiveness in human endothelial cells.

Elevated Coexpression of KITENIN and the ErbB4 CYT-2 Isoform Promotes the Transition from Colon Adenoma to Carcinoma Following APC loss

PURPOSE AND EXPERIMENTAL DESIGN

The molecular events in the malignant progression of colon adenoma after loss of adenomatous polyposis coli (APC) are not fully understood. KITENIN (KAI1 C-terminal interacting tetraspanin) increases the invasiveness of colorectal cancer cells, and we identified a novel EGFR-independent oncogenic signal of EGF that works under coexpressed KITENIN and ErbB4. Here we tested whether elevated KITENIN and ErbB4 contribute to further progression of intestinal adenoma following APC loss.

RESULTS

The intestinal tissues of villin-KITENIN transgenic mice in which villin-driven KITENIN expression induces increased c-Jun expression exhibit mild epithelial cell proliferation but no epithelial lineage changes compared with those of nontransgenic mice. Among the four ErbB4 isoforms, JM-a/CYT-2 and JM-b/CYT-2 exhibited the highest AP-1 activity when cells coexpressing KITENIN and each isoform were stimulated by EGF. Interestingly, predominant overexpression of the ErB4-CYT-2 mRNA as well as increased EGFR expression were observed in intestinal adenoma of APC(min/+) mice, which makes the microenvironment of activated EGF signaling. When we crossed villin-KITENIN mice with APC(min/+) mice, intestinal tumor tissues in the crossed mice showed the characteristics of early-stage invading adenocarcinoma. In patients with colorectal cancer, ErbB4-CYT-2 mRNA expression was significantly greater in tumor tissues than in normal adjacent tissues, but no significant differences in tumor tissue expression were found between different colorectal cancer stages. Furthermore, the mRNA expression of KITENIN and that of ErbB4-CYT-2 were positively correlated in human colorectal cancer tissue.

CONCLUSIONS

Elevated coexpression of KITENIN and ErbB4-CYT-2 promotes the transition of colon adenoma to adenocarcinoma within an APC loss-associated tumor microenvironment.

Lichen Secondary Metabolite, Physciosporin, Inhibits Lung Cancer Cell Motility

Lichens produce various unique chemicals that can be used for pharmaceutical purposes. To screen for novel lichen secondary metabolites showing inhibitory activity against lung cancer cell motility, we tested acetone extracts of 13 lichen samples collected in Chile. Physciosporin, isolated from Pseudocyphellaria coriacea (Hook f. & Taylor) D.J. Galloway & P. James, was identified as an effective compound and showed significant inhibitory activity in migration and invasion assays against human lung cancer cells. Physciosporin treatment reduced both protein and mRNA levels of N-cadherin with concomitant decreases in the levels of epithelial-mesenchymal transition markers such as snail and twist. Physciosporin also suppressed KITENIN (KAI1 C-terminal interacting tetraspanin)-mediated AP-1 activity in both the absence and presence of epidermal growth factor stimulation. Quantitative real-time PCR analysis showed that the expression of the metastasis suppressor gene, KAI1, was increased while that of the metastasis enhancer gene, KITENIN, was dramatically decreased by physciosporin. Particularly, the activity of 3’-untranslated region of KITENIN was decreased by physciosporin. Moreover, Cdc42 and Rac1 activities were decreased by physciosporin. These results demonstrated that the lichen secondary metabolite, physciosporin, inhibits lung cancer cell motility through novel mechanisms of action.

Mst2 Controls Bone Homeostasis by Regulating Osteoclast and Osteoblast Differentiation

Mammalian sterile 20-like kinase 2 (Mst2) plays a central role in the Hippo pathway, controlling cell proliferation, differentiation, and apoptosis during development. However, the roles of Mst2 in osteoclast and osteoblast development are largely unknown. Here, we demonstrate that mice deficient in Mst2 exhibit osteoporotic phenotypes with increased numbers of osteoclasts and decreased numbers of osteoblasts as shown by micro-computed tomography (µCT) and histomorphometric analyses. Osteoclast precursors lacking Mst2 exhibit increased osteoclastogenesis and Nfatc1, Acp5, and Oscar expression in response to receptor activator of NF-κB ligand (RANKL) exposure. Conversely, Mst2 overexpression in osteoclast precursors leads to the inhibition of RANKL-induced osteoclast differentiation. Osteoblast precursors deficient in Mst2 exhibit attenuated osteoblast differentiation and function by downregulating the expression of Runx2, Alpl, Ibsp, and Bglap. Conversely, ectopic expression of Mst2 in osteoblast precursors increases osteoblastogenesis. Finally, we demonstrate that the NF-κB pathway is activated by Mst2 deficiency during osteoclast and osteoblast development. Our findings suggest that Mst2 is involved in bone homeostasis, functioning as a reciprocal regulator of osteoclast and osteoblast differentiation through the NF-κB pathway.