bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 1943: Anticarcinogenic effect of curcumin by insulin-like growth factor-1 signaling inhibition
Authors: Kim Hyoseon , Kim Eunjung
Published: August 2014

Curcumin (diferuloylmethane) is an active polyphenol natural product isolated from turmeric (the rhizome of the plant Curcuma longa Linn) and is traditionally used as a coloring agent and spice in food. Curcumin has also been shown to a powerful therapeutic agent against many human diseases including cancer. Insulin-like growth factor-1(IGF-1) signaling plays a critical role in regulation of cell survival, proliferation and growth. In this study, we investigated IGF-1 signaling inhibitory activity of curcumin and its mechanism in in vitro cell culture studies and in vivo tumor studies using BK5. IGF-1 transgenic mice.

Serum starved HeLa cells were treated with curcumin of various concentrations and times and then stimulated with IGF-1(20 ng/ml) for 30 min. Akt(S473) and S6K(T389) phosphorylation was inhibited by 1 hr treatment of 40 and 30 μM curcumin, respectively. Moreover, curcumin treatment inhibited S6K phosphorylation even after 10 min treatment. Akt was not affected at this dosage and time of curcumin treatment. Curcumin also inhibited amino acids stimulated S6K phosphorylation whereas it activated Akt phosphorylation by negative feedback inhibition. This S6K phospholylation inhibitory activity of curcumin was comparable to that of rapamycin(20 nM) but the effect of curcumin appears to be transient.

In our in vivo tumor study, supplementaion of curcumin to AIN-93G diet(0.02 % curcumin wt/wt) decreased mouse skin tumor multiplicity by 50 % as well as tumor size in BK5. IGF-1 transgenic mice. Curcumin supplementation also inhibited skin epithelial cell proliferation in 5-bromo-2-deoxyuridine(BrdU) incorporation experiment.

Taken together, these data suggest that curcumin may exert its anticarcinogenic effect by directly inhibit IGF-1 stimulated mammalian target of rapamycin(mTOR) signaling.

[This research was supported by Basic Science Research Program(C00308) and by SRC program(Center for Food & Nutritional Genomics:2010-0001886) through the National Research Foundation of Korea(NRF) funded by the Ministry of Education, Science and Technology.]

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1943. doi:10.1158/1538-7445.AM2011-1943
Abstract 1945: Inhibition of PTK6 kinase activity reduces proliferation and migration of tumor cells
Authors: Wang Yan , Malkowski Michael , Jin Weihong , Belanger David , Zeng Hongbo , Curran Patrick J. , Siddiqui M. Arshad , Miao Hua , Shipps Gerald W. , Hailey Judith , Maxwell Eugene , Carr Donna , Seidel-Dugan Cynthia
Published: August 2014

Protein kinase 6 (PTK6) is a member of the Frk family of non-receptor tyrosine kinase that is overexpressed in several types of cancers with the highest overexpression observed in breast tumors. PTK6 shows sequence homology to the src tyrosine kinase family. Its functional domains, including a SH3, a SH2 and a kinase domain, are arranged similarly with src family kinases although PTK6 lacks a myristoylation domain. We have identified a potent small molecule PTK6 kinase inhibitor from kinase cross screens that inhibits PTK6 autophosphorylation and phosphorylation of its substrate Sam68, a member of the KH domain containing RNA binding proteins. In cell culture, the compound inhibited proliferation, soft agar growth and migration of tumor cells. The compound inhibited soft agar growth of breast tumor cells more potently than dasatinib. A specific PTK6 kinase inhibitor may provide a novel approach to inhibit the growth of selected tumors, sensitize the response of the tumor cells to other chemotherapeutics and prevent/inhibit metastasis of cancer in a wide range of cancer patients.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1945. doi:10.1158/1538-7445.AM2011-1945
Abstract 1946: Detecting protein-protein interactions between MUC16 CDΔ102 (80AA) and a SKOV-3 cDNA library using yeast two-hybrid screening
Authors: Polterauer Stephan , Parlett Ryan , Thapi Dharmarao , Rosales Nestor , Spriggs David R. , Yan Xiu J.
Published: August 2014

MUC16 is a membrane-bound mucin that extends from the surface of ovarian cancer cells. Recent studies suggest that MUC16 influences carcinogenesis and metastasis of ovarian cancer cells. It is expected that protein-protein interactions play a crucial role in MUC 16 signaling and oncogenic transformation.

To define the mandatory molecular partners for MUC16 signaling and transformation, we investigated potential protein binding partners, using a classic yeast two-hybrid screening. The 80AA MUC16-CDΔ102 construct (ectodomain deletion mutant) was cloned into the bait plasmid pGBKT7 and transformed into Y2HGold yeast cells, allowing expression of MUC16-CDΔ102 fused to the Gal4 DNA-binding domain (BD). A SKOV-3 cDNA library was generated and cloned into the prey plasmid pGADT7 and transformed into yeast cells, allowing expression of cDNAs fused to the Gal4 activation domain (AD). Bait and prey yeast cells were allowed to bind to potential partners and bringing the BD and AD into proximity to each other, which then activated transcription of three reporter genes. An array of diploid yeast clones was produced, by co-culturing the two strains overnight, each co-expressing the bait with a different library prey protein. The clone pool was plated on selective media (basic SD-/Trp with Agar) and incubated to screen for individual clones that express the appropriate reporter genes and markers, indicating the presence of interacting hybrid protein pairs. Prey plasmids were then isolated from yeast cells and DNA fragments of the positive clones were amplified by PCR to determine the interacting binding partner.

Seven potential binding proteins (no. of colonies), i.e. TTC1 (4), DARS (1), MAPK1IP1L (1), FAM175B (1), SEPT2 (1), CAMLG (4), and SKAP2 (3), were identified. Protein-complex immuno-precipitation analysis is planned to confirm the interactions between the seven potential binding proteins in human ovarian cancer cell lines, in order to verify that each identified member of the protein complex was a valid identification.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1946. doi:10.1158/1538-7445.AM2011-1946
Abstract 1949: Proliferation of cell lines from pancreatic ductal adenocarcinomas and ductal epithelia are stimulated by acute and chronic exposure to nicotine and ethanol via modulation in neurotransmitter production
Authors: Al-Wadei Mohammed H. , Al-Wadei Hussein A. , Schuller Hildegard M.
Published: August 2014

Pancreatic cancer is the leading cause of cancer mortality in both men and women in western countries due to its unresponsiveness to available therapeutics. It is well documented that smoking, diabetes and pancreatitis from chronic alcohol consumption are risk factors for this type of cancer. More than 95% of pancreatic cancers are pancreatic ductal adenocarcinomas (PDACs) that arise from pancreatic ductal epithelia. Our lab has previously shown that nicotine stimulates the proliferation and migration of human small airway epithelial cells and the adenocarcinomas derived from them in vitro due to nicotine induced changes in the sensitivity of the nicotinic acetylcholine receptors. Such changes caused an increase in the production and secretion of excitatory neurotransmitters, but decreased the production and secretion of inhibitory neurotransmitter γ-aminobutyric acid (GABA). In analogy to these findings in lung cells, both nicotine and ethanol stimulated cell proliferation in PDAC cell lines Panc-1 and BXPC-3 and in immortalized pancreatic duct epithelial cells HPDE6-C7. Acute and chronic treatment of all cell lines with nicotine or ethanol alone and in combination significantly increased the production of noradrenaline and adrenaline by the cells while significantly reducing GABA production. Western blots are currently underway to assess the potential modulation of nicotinic receptor protein expression as well signaling pathways. Our findings suggest a potential role for these pathways contributing to the development of smoking and alcohol related pancreatic carcinogenesis and may result in the identification of novel targets for the prevention and therapy of this malignancy.

Supported by R01CAo42829 with the National Cancer Institute.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1949. doi:10.1158/1538-7445.AM2011-1949
Abstract 195: Cell death pathway activation during monocytic / macrophagic differentiation of hematopoietic tumor cell lines
Authors: de Séllos João , Caetano Mauricio S. , Carvalho Erika , Amarante-Mendes Gustavo P. , Ferreira Carlos G. , Sternberg Cinthya
Published: August 2014

Apoptosis is a phenomenon of cellular degeneration highly conserved evolutionarily, being observed not only during development, but also associated with a number of diseases. Apoptosis is regulated by a complex set of proteins and accomplished by biochemical mechanisms that act to initiate and complete the destruction of the cell. Recently, typical biochemical and morphological changes associated to cell death were correlated with other vital cellular events, such as proliferation and differentiation. Despite the general tendency to treat apoptosis and cell differentiation as the result of different signaling pathways, several studies have shown that there is a high degree of morphological similarity between these events. The molecules involved in the regulation of apoptosis-like processes of differentiation have not been fully described. Since the main endogenous inhibitor of caspase-3 is the protein XIAP, which in turn is regulated by XAF1, we analyzed the expression of these proteins in the context of differentiation of different cell lines. The objective of this study was to evaluate the activation pathways of cell death in the process of monocytic/macrophage differentiation.

We have observed that the expression of XAF1 protein decreases during monocytic/macrophage differentiation of HL60 cell line induced by PMA, but levels of its mRNA do not change. Interestingly, we have found that HL60 cell lines overexpressing either Bcl-XL or Bcl-2 cell lines have decreased expression of XAF1 due to methylation of its promoter. Also, besides rendering cells resistant to apoptosis as expected, HL60 cells overexpressing either Bcl-XL or Bcl-2 were more prone to differentiate by PMA treatment than parental cells. The correlation between high levels of mRNA expression of Bcl-2 with low expression of XAF1 mRNA was also observed in the analysis of samples from patients with follicular lymphoma retrieved from Oncomine database (www.oncomine.com). These results demonstrate the differential activation of pathways of cell death in monocytic / macrophagic differentiation, suggesting that a descrease in XAF1 expression is a necessary event during this process. Furthemore, our results reveal a transcriptional regulatory loop exerted by Bcl-2 family of proteins that had not yet been described.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 195. doi:10.1158/1538-7445.AM2011-195
Abstract 1950: The effects of combination treatment of NO-donor and MEK inhibitor on proliferation and invasion of cancer cell lines
Authors: Furuhashi Satoshi , Sugita Hiroki , Takamori Hiroshi , Horino Kei , Nakahara Osamu , Okabe Hirohisa , Abe Shinya , Tanala Hiroshi , Beppu Toru , Baba Hideo
Published: August 2014

[Background] Nitric oxide (NO) possesses cytostatic and cytotoxic actions on cancer cells. MAPK and PI3K/Akt signaling pathways, those exist downstream of IGF-IR and EGFR, are two major pathways of oncogenic transformation and tumor maintenance in many kinds of cancer cells. Several studies demonstrated that NO inhibits PI3K/Akt pathway, on the other hand, NO enhances activates MAPK pathway by means of activation of H- and N-Ras. MEK inhibitor blocks MAPK pathway. Hence, we hypothesized that combination of NO-donor and MEK inhibitor inhibits proliferation and invasion of cancer cells in comparison with NO-donor or MEK inhibitor alone. [Methods and Results] We assessed effects of combination of GSNO (NO-donor) and U0126 (MEK inhibitor) on phosphorylation of Akt, and Erk1/2 after stimulation of IGF-I and EGF using Western blotting analyses. Combination of GSNO (500 μM) and U0126 (10 μM) down-regulates phosphorylation of Akt, and Erk1/2 after stimulation of IGF-I (25 nM) and EGF (100 ng/ml) more strongly in comparison with GSNO or U0126 alone in MIAPaCa-2 cells and HCT-116 cells. Combination of GSNO (200, 500 μM) and U0126 (10 μM) also inhibited cell proliferation of MIAPaCa-2 cells and HCT-116 cells more strongly in comparison with NO-donor or MEK inhibitor alone. Furthermore, combination of these compounds inhibited invasion of MIAPaCa-2 cells and HCT-116 cells more strongly in comparison with NO-donor or MEK inhibitor alone in vitro. [Discussion] Recent reports revealed that inhibition of PI3K/Akt or MAPK pathway alone was insufficient to robustly induce tumor shrinkage. It indicated that a feedback pathway between intracellular signalings might be up-regulated, if one main signaling pathway was inhibited. Concomitant inhibition of both PI3K/Akt and MAPK pathway by means of NO-donor and MEK inhibitor could inhibit not only cell growth but also invasion to suppress feedback loops. These results suggest that the combination treatment of NO-donor and MEK inhibitor may be useful for cancer therapy.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1950. doi:10.1158/1538-7445.AM2011-1950
Abstract 1951: Inhibition of aurora kinase using VX-680 enhances the radiation response in glioma cells
Authors: Jane Esther P. , Premkumar Daniel R. , Pollack Ian F.
Published: August 2014

The central role of aurora kinases in cell cycle regulation coupled with overexpression of aurora A and B kinases in a wide variety of human malignancies that led to the development of pharmacological inhibitors of aurora kinases. New generations of aurora inhibitors, including VX-680, has been evaluated preclinically and are in phase I and II trials for the treatment of solid tumors and leukemia. In this study, we investigated the role of VX680, Aurora kinase inhibitor in malignant human glioma cells with different p53 statuses as well as cytotoxicity of glioma cells to irradiation. VX-680 inhibits aurora A and B kinases and cell proliferation with nanomolar to low micromolar potency. Endoreduplication, the re-replication of DNA in the absence of mitotic division, ultimately results in polyploidy and inhibition of cell proliferation. VX680 treatment led to an increase in the number of multinucleated cells and the ratios of G2/M phase in p53-mutant (LN229) and p53-deleted cells (LNZ308), but minimal in p53-wild type (A172) glioma cells. FACS analysis revealed that the increase in nuclear size correlated with polyploidization, reaching a >16 DNA content on day 2. During mitosis, the cells rounded normally, condensed their chromosomes on a metaphase-like plate. Our results demonstrate that pretreating cells with VX-680 prior to ionizing radiation led to an enhancement of radiation -induced apoptosis. Accordingly, our results suggested that Aurora kinase inhibition followed by irradiation increases in the appearance of multinucleated cells and increase apoptosis, and this treatment may become a potential therapy against malignant human gliomas.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1951. doi:10.1158/1538-7445.AM2011-1951
Abstract 1958: Glypican-3 (GPC3) modulates senescence, homotypic adhesion and migration of tumor mammary cells through the inhibition of the canonical Wnt pathway
Authors: Lago Huvelle María A. , Buchanan Cecilia , Romero Silvina A. , de Kier Joffé Elisa Bal , Peters María Giselle
Published: August 2014

The Wnt pathway is involved in regulating cell proliferation and differentiation. Alterations of this pathway have been identified as key event in neoplastic development.

Previously, we have demonstrated that the restatement of Glypican-3 (GPC3), a proteoglycan downregulated in breast cancer, is able to induce an inhibition of the canonical Wnt pathway in the murine mammary adenocarcinoma LM3 cells. We also reported that GPC3 reexpression induces an inhibition of the in vivo metastatic capacity and an in vitro reversion of the epithelial to mesenchymal transition (EMT). GPC3 reexpressing clones are less viable in stress conditions, more senescent, more homotypic adherent, less migrants and their actin is mainly localized in cortical position.

The aim of this study was to analyze whether the effects of GPC3 on these cellular parameters are dependent on the inhibition of canonical Wnt pathway. As a strategy, two LM3-GPC3 clones and two LM3-vector ones were treated with LiCl (activator of the Wnt pathway canonical) or NaCl as control. We determined that LiCl was able to partially reverse the LM3-GPC3 cell senescence (X-gal positive senescent cells: LM3-GPC3+NaCl=85% vs +LiCl=65%, ANOVA-Bonferroni p <0.05). In contrast, no changes were observed on the susceptibility to death by serum starving (ANOVA, ns). Although there were no effects on the actin cytoskeleton organization, we established by a wound healing assays that LM3-GPC3 cells treated with LiCl regain their ability to migrate (Wound coverage: LM3-GPC3+NaCl=15% vs +LiCl=75%, ANOVA-Bonferroni p<0.05). Interestingly, LiCl significantly reduced the homotypic adhesion of LM3-GPC3 cells, reaching control levels (ANOVA-Bonferroni p<0.05).

These results suggest that inhibition of the canonical Wnt pathway induced by GPC3 mediates the effects of this glypican on senescence, migration and cell aggregation, while survival and actin cytoskeleton organization would be modulated through other pathways.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1958. doi:10.1158/1538-7445.AM2011-1958
Abstract 1959: Identification of inhibitors specific for torc2 as strategy to overcome feedback erk activation in multiple myeloma cells when treated with second generation mtor inhibitors
Authors: Hoang Bao , Benavides Angelica , Bernath Andrew , Cloninger Cheri , Artinian Nicholas , Bashir Tariq , Gera Joe , Lichtenstein Alan
Published: August 2014

Recent data indicate that the second generation mTOR inhibitor, pp242, which inhibits TORC2 as well as TORC1, is much more effective against multiple myeloma (MM) cells than rapamycin, a first generation inhibitor which only curtails TORC1 activity. A major reason for this improved efficacy may be that pp242 prevents the feedback activation of AKT that results from rapamycin's inhibition of TORC1. It does this by inhibiting TORC2-induced AKT phosphorylation on S473. However, an additional feedback cascade that results from TORC1 inhibition is activation of MEK/ERK. Indeed, our data show that ERK activation is significant in MM cells exposed to either rapamycin or pp242. Pp242 was comparably potent for activating ERK in rictor-knocked down MM cells, supporting the contention that feedback activation was due to TORC1 inhibition. To examine whether this pp242-induced activation of ERK antagonizes pp242's cytotoxic effects, we co-exposed MM cells with pp242 + the ERK inhibitor U0126, using concentrations of the latter that abrogated ERK phosphorylation in pp242-treated MM cells. There was a marked synergistic effect, indicating ERK feedback activation is a mechanism of resistance to pp242. To address this problem, we performed a drug screen in a yeast-two hybrid system to identify compounds that prevented an interaction between rictor and mTOR. Our reasoning was that such an agent could be a specific TORC2 inhibitor without effects on TORC1 and, thus, without induction of feedback ERK activation. We identified several potential compounds and have begun to characterize their molecular activity. One of the most active agents in the drug screen is capable of inducing cytoreduction of MM cells in MTT assays with ED50s of approx 0.7-0.9 uM and significant MM cell apoptosis when used at 1 uM. This cytotoxic effect was accompanied by a down-regulation of TOR activity which was specific for TORC2 (ie., decreased S473 AKT phosphorylation). Most importantly, there was no activation of ERK in cells treated with this TORC2-specific agent. These data indicate feedback ERK activation may be a resistance mechanism when second generation mTOR inhibitors are used and suggest a strategy for preventing activation.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1959. doi:10.1158/1538-7445.AM2011-1959
Abstract 1961: PKCΔ mediates glycodelin-induced differentiation of breast cancer cells
Authors: Hautala Laura C. , Koistinen Riitta , Koistinen Hannu
Published: August 2014

Glycodelin is a secreted lipocalin family glycoprotein, expressed mainly in differentiated epithelia in reproductive tissues. The expression of glycodelin in breast and endometrial cancer cells induces cell differentiation. We have found that transfection of glycodelin cDNA into MCF-7 breast cancer cells changes cellular morphology and gene expression towards less malignant direction. In pre-clinical xenograft mouse model glycodelin-producing cells formed significantly smaller tumors with lower proliferation rate than control cells. This is in keeping with the association of glycodelin with well-differentiated and less proliferative tumors in sporadic breast cancer patients. The aim of the present study is to elucidate the mechanism(s) mediating glycodelin-induced differentiation of breast cancer cells.

The gene expression changes between glycodelin-producing and control cells were compared using a cDNA micro array. The cells were grown on Matrigel with and without protein kinase C (PKC) activator phorbol 12-myristate 13-acetate (PMA), PKCΔ inhibitor Rottlerin and various other kinase inhibitors. PKCΔ was also down-regulated with RNAi. The levels of PKCΔ were measured using Western Blotting.

The gene expression changes induced by glycodelin were enriched in several pathways, including mitogen-activated protein kinase (MAPK) -pathway. Among various studied proteins of MAPK-pathway, we found that phosphorylated PKCΔ was down-regulated in glycodelin-producing cells. Further studies with activators and inhibitors indicated that addition of PKC activator PMA to cell culture medium induced dramatic morphological changes and increased motility of the control cells, while glycodelin-producing cells were unresponsive. The effect of PMA was abolished by Rottlerin, an inhibitor of PKCΔ, as well as by using siRNA for PKCΔ. These results suggest that the glycodelin-induced differentiation of breast cancer cells is mediated by PKCΔ, which in other studies has been proposed to be a potential target for cancer treatment.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1961. doi:10.1158/1538-7445.AM2011-1961
Abstract 1962: Helicobacter pylori cytotoxin associated protein CagA represses TGF-β signaling through interaction with Smad proteins
Authors: Lee Ho-Jae , Nguyen Thuy Trang , Cho Han-Yang , Kim Kyoung-Mi , Kim Cho-Rong , Hahm Ki-Baek
Published: August 2014

Helicobacter pylori infection causes chronic gastric inflammation and peptic ulceration, and is the strongest risk factor for the development of gastric cancer. The cagA (cytotoxin-associated gene A) gene which is one of the most important virulence factors of H. pylori, is believed to contribute to the gastric tissue injury and cancer development. Transforming growth factor-β (TGF-β) signaling plays a pivotal role in modulating gastric mucosal inflammatory responses. Recently, H. pylori infection has been associated with attenuated TGF-β signaling in gastric mucosa. However, the precise underlying mechanism of H. pylori infection on TGF-β signaling and inflammatory response remains unclear. In this study, we examined the mechanism of inhibition of TGF-β signaling by H. pylori CagA protein. CagA suppressed TGF-β/Smad transcriptional responses. CagA interacted constitutively with Smad proteins, and most strongly with Smad3. Expression of CagA on AGS cells inhibited TGF-β-induced down-regulation of proinflammatory chemokines, such as CXCL1, CXCL3 and IL-8, as well as TGF-β-induced transcription of target genes. These results suggest that the attenuated TGF-β signaling associated with cagA-positive H. pylori infection could be an important determinant for the degree of inflammation provoked by H. pylori.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1962. doi:10.1158/1538-7445.AM2011-1962
Abstract 1968: Obesity-induced activation of the androgen receptor
Authors: Siddiqui Faryal A.
Published: August 2014

Background: Prostate cancer is the second leading cause of cancer deaths for men in the US. Obesity increases the risk of dying from prostate cancer by almost 50%. The mechanisms by which obesity promotes a more aggressive disease remain largely unknown, hindering the development of effective approaches for improving patient outcome. It is hypothesized that because obesity is associated with elevated circulating levels of growth factors, activation of the androgen receptor may be responsible for the increased risk of a more aggressive cancer in obese men. This current study investigates the effects of obese sera on androgen receptor activity in a highly novel prostate cancer cell line.

Methods: LNCaP prostate cancer cells were stably infected with a lentiviral Dual-Luciferase reporter plasmid containing an androgen receptor response element (ARE). These stable ARE-reporter cells were then exposed to sera from either obese or control weight mice. Specific signal transduction inhibitors were used to determine the role of growth factor signaling in mediating the effects observed in response to exposure to the different sera.

Results: Exposure to obese sera activated the androgen receptor to levels three-fold greater than those seen with control sera. Intriguingly, use of a PI3 kinase inhibitor reduced obesity-induced activation of the AR by 75%, but only by 64% in the control sera. Studies are on-going to determine the role of both the Akt and MAPK pathways in these results, as well as the relative contribution of circulating androgens in activating the AR. Downstream targets of the AR induced by exposure to the obese sera are being identified both by Western blot and microarray analyses.

Conclusions: These results suggest that obesity-related circulating factors induce activation of the androgen receptor in prostate cancer cells. This activation appears to be both ligand dependent (androgens) and ligand independent (growth factors). These data suggest that one mechanism by which obesity influences time to progression and hormone independence is through activation of the androgen receptor.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1968. doi:10.1158/1538-7445.AM2011-1968
Abstract 1969: Mapping the cross talk between parathyroid hormone related protein (PTHrP) and Integrins α6 and β4 in prostate cancer cells
Authors: Bhatia Vandanajay , Mula Ramanjaneya V. , Falzon Miriam A.
Published: August 2014

Prostate carcinoma is a leading cause of cancer deaths in men in the United States. An estimated 217,730 new cases and 32,050 deaths from prostate cancer have been reported in 2010 by the National Cancer Institute. For a cancer cell to become malignant it must adopt mechanisms to escape and survive outside its original environment, thus avoiding apoptosis. Parathyroid hormone-related protein (PTHrP) is among the many factors that contribute to this pro-survival state. The mechanisms through which PTHrP affects cell malignancy are not well understood.

Our previous studies have shown that PTHrP increases cell-surface levels of integrin α6β4 in prostate cancer cells. Over-expression of integrin α6β4 correlates with increased tumor invasion and metastasis. Integrin α6β4 also acts as a signaling molecule that activates anti-apoptotic phosphoinositide 3-kinase (PI3K) signaling pathways. The mechanism through which PTHrP increases α6 and β4 integrins levels is not clear.

We report that in PTHrP over-expressing prostate cancer cell lines (C4-2 and PC-3), the activity of α6 and β4 promoters is increased by ∼ 2.5 fold. We have also found increased NF-κB promoter activity in C4-2 and PC-3 cell lines as a result of PTHrP over-expression. Identification of elements within the integrin α6 and β4 gene promoters that are regulated by PTHrP signaling can provide valuable information regarding the mechanism of the PTHrP action in cancer cell survival and invasion. PTHrP also regulates α6 and β4 protein levels via a post-translational pathway, since the PTHrP protein half-life is higher in PTHrP-over expressing cells in comparison to empty vector control cells. This effect is mediated via the proteasome pathway, as ubiquitinated α6 and β4 levels are reduced in PTHrP over-expressing cells. Our future goals are to map the regulatory elements like NF-κB in the α6 and β4 integrin promoters that are regulated by PTHrP, and to identify the pathways via which PTHrP regulates the proteasome pathway. This might help understand the mechanism through which PTHrP acts in prostate cancer.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1969. doi:10.1158/1538-7445.AM2011-1969
Abstract 1976: Systematic identification of protein-protein interactions by Proximity Ligation Assay
Authors: Chen Tzu-Chi , Lin Kuan-Ting , Kuo Yu-Lun , Lee Pei-Ying , Chen Chun-Houh , Liu Yu-Wen , Huang Chi-Ying
Published: August 2014

Signal transduction pathways at cellular level require massive protein-protein interactions (PPIs) in response to different environmental cues. Diverse experimental techniques for detecting PPIs have been developed; however, the large amount of data accumulated from various sources has posed a grand challenge in data reliability for PPI. To evaluate the role of PPIs within signaling pathways, we have systematic profiled PPI residing in 28 KEGG pathways, for example mTOR, MAPK, Wnt, VEGF, and Hedgehog, and 3 cancer-related pathways stored in KEGG (http://www.genome.jp/kegg/). Of ∼60000 human PPI collected, 2786 PPI can be detected within targeted 14 pathways. To validate these PPIs, we used a newly developed Proximity Ligation Assay, which detects endogenous PPI through a pair of antibodies that bind to proteins in close proximity. Each PPI can be made visible through DNA amplification and quantified by counting fluorescent dots in the cell. Of 1,204 PPIs examined, 557 PPIs can be confirmed in HeLa cells. Specifically, 383 out of 557 validated PPIs residing within pathways in cancer and mTOR, Wnt and MAPK pathways are considered novel “links” based on annotations of KEGG. Moreover, 79 validated PPIs are cross-talk events among 35 signaling transduction and cancer related pathways. Surprisingly, only 16 PPIs (out of 557 confirmed PPIs) are highly correlated in 7 sets of cancer cells from NCI60 microarray dataset. In this large scale PPI profiling, 41 apoptosis related PPIs were further tested in 3 cancer cell lines to explore the possibility for drug screening. These systematic analyses of endogenous PPI pairs within and between pathways may set the foundation to disrupt the signaling pathways by targeting PPIs in cancer drug discovery.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1976. doi:10.1158/1538-7445.AM2011-1976
Abstract 198: TRAF2 phosphorylation is essential for cancer-cell adaptation to chronic cellular stress
Authors: Habelhah Hasem , Blackwell Ken , Zhang Laiqun
Published: August 2014

The tumor microenvironment is known to trigger chronic endoplasmic reticulum (ER) and oxidative stresses, and cancer-cell adaptation to such chronic stresses has profound consequences for malignant progression and the response to therapy. TRAF2 regulates cellular response to TNFα, ER and oxidative stresses by activating the JNK/c-Jun and IKK/NF-κB signaling cascades. We mapped two phosphorylation sites (Ser-11 and Ser-55) on the N-terminal RING domain of TRAF2, and reported that phosphorylation at these sites increases basal and TNFα-induced NF-κB activation. Recently, we identified TBK1 and PKCζ as the kinases that directly phosphorylate TRAF2 at Ser-11 and Ser-55 sites, respectively. We found that in addition to TNFα, ER and oxidative stresses also strongly induce TRAF2 phosphorylation at both sites. This dual phosphorylation of TRAF2 promoted IKK activation and inhibited the prolonged phase of JNK activation in response to ER and oxidative stresses. Importantly, TRAF2 phosphorylation was found to be essential for cancer-cell survival under conditions of chronic cellular stress. Specifically, the endogenous TRAF2-dockdown cancer cells that were stable expressed with phospho-null-mutant TRAF2 (TRAF2-S11/55A) did not survive under conditions of chronic ER and oxidative stresses, while their TRAF2-WT counterparts survived under the same conditions. In addition, the TRAF2-S11/55A-expressing cancer cells formed significantly smaller tumors in vivo and exhibited greater sensitivity to anti-cancer drug-induced apoptosis than did TRAF2-WT-expressing counterparts. Functional assays revealed that TRAF2 phosphorylation not only promotes NF-κB-dependent gene expression, but also suppresses JNK-mediated degradation of Bcl-2 and cIAP1 at post-transcriptional level in the context of ER and oxidative stresses. Collectively, these findings suggest that TRAF2 phosphorylation plays a critical role in tumor progression by promoting the expression of anti-apoptotic proteins in cancer cells, and could be a new target for anti-cancer drug development.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 198. doi:10.1158/1538-7445.AM2011-198
Abstract 1982: TGF-beta induced SIK cooperates with Smurf2 to negatively regulate type I receptor kinase signaling
Authors: Vanlandewijck Michael , Lönn Peter , Kowanetz Marcin , Kowanetz Katarzyna , Bush Christer , Heldin Carl-Henrik , Moustakas Aristidis
Published: August 2014

Signal transduction pathways, like transforming growth factor beta (TGFβ), regulate many physiological processes and require control mechanisms to safeguard proper and timely action. Dysregulation of TGFβ signaling is established as a major player in cancer progression. We have recently described how negative regulation of TGFβ signaling is controlled by the serine/threonine kinase salt-inducible kinase (SIK). SIK is induced by TGFβ and forms protein complexes with the TGFβ type I receptor and with the inhibitory Smad7, which leads to type I receptor downregulation. We now investigate this mechanism further and demonstrate similarities between TGFβ/Smad-mediated immediate-early induction of SIK and Smad7. We also relate another protein of the negative feedback loop of TGFβ signaling, the E3 ubiquitin ligase Smurf2, to this mechanism of regulation. We provide evidence that Smurf2 cooperates with SIK to downregulate the type I receptor. Both the kinase activity of SIK and the ubiquitin ligase activity of Smurf2 are important for proper receptor turnover. However, Smurf2 does not directly bind to SIK, but participates in the complex via the PY-motif of Smad7. We thus establish a central role for Smad7 during SIK-mediated receptor downregulation. Finally, we explore the role of SIK in a cancer context by investigating its expression profile in human prostate cancer tissues. In conclusion, we have uncovered a phosphorylation/ubiquitination-dependent mechanism for TGFβ receptor downregulation that could play important roles during cancer progression.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1982. doi:10.1158/1538-7445.AM2011-1982
Abstract 1985: The activation of GSK3 by HGF-MET axis is responsible for differentiation of rhabdomyosarcoma cells
Authors: Miekus Katarzyna , Bobela Wojciech , Majka Marcin
Published: August 2014

Introduction: Rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma among children. At the late stages (metastatic) the outcome for the patients is very poor. The molecular basis for loss of cell differentiation in the process of carcinogenesis is not well understood. Differentiation status of rhabdomyosarcoma cells strongly influences its progression and metastatic ability and therefore the overall patient survival.

At the onset of myogenic differentiation MET receptor is rapidly downregulated and on the other hand the activation of MET receptor in rhabdomyosarcoma has been shown to influence proliferation, survival and migration.

Aim: Dissecting the role of HGF-MET receptor axis and GSK3 activation in the process of RMS differentiation.

Materials and methods: Cell lines used in experiments: RH30 (ARMS), SMS-CTR (ERMS). Real time RT-PCR and western blotting were used to evaluate gene expression and the activation of various intracellular signaling pathways, respectively. The evaluation of protein activation in RMS cell lines was performed after stimulation with HGF.

Results: We found that, during differentiation process the expression of MyoD, characteristic for poorly differentiated rhabdomyosarcoma cells decreased and the expression of myogenin, protein characteristic for differentiated/ matured muscle cells increased. That was paralleled by decreased expression of MET receptor. In RMS cell lines with stable downregulation of MET receptor the expression of differentiation related genes was similar to differentiated RMS cells. When we study the activation of GSK3 we observed the phosphorylation of GSK3 beta on serine 9 after HGF stimulation. The intracellular pathway responsible for GSK3 beta phosphorylation turn out to be PI3K-AKT dependent. We observed also the accumulation of beta-catenin in the nucleus of RMS cells stimulated with HGF. This effect was father augmented when HGF was used together with BIO, small molecular inhibitor of GSK3 beta.

Conclusion and future directions: In this study we have shown that the expression and signaling of MET receptor is responsible for differentiation of RMS cells. Moreover we postulate that MET receptor exerts its influence on RMS cells differentiation through GSK3 beta activation. These findings might have the significant clinical implication for the treatment of RMS cells because they suggest that induction of differentiation of RMS cells by blocking MET receptor could inhibit growth of RMS tumors. Finally, we think that also GSK3 beta could be used as the new therapeutic target to induce differentiation of RMS.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1985. doi:10.1158/1538-7445.AM2011-1985
Abstract 1987: Identification and characterization of novel Notch3 interacting proteins in ovarian cancer
Authors: Stoeck Alexander , Chen Xu , Shih Ie-Ming , Wang Tian-Li
Published: August 2014

Ovarian serous carcinoma (OSC) represents one of the most aggressive neoplastic diseases because most cases present at an advanced stage when therapy is usually ineffective. We have previously reported that Notch3 gene amplification and overexpression occurs frequently in OSC. Activation of Notch3 signaling is essential for the survival of OSC cells with Notch3 overexpression, especially in the presence of chemotherapeutic agents. Notch3 pathway activation has been known to transcriptionally regulate an array of genes, including those involved in stem cell biology and oncogenesis in OSC. The current study aims at identifying the binding proteins of Notch-ICD in OSC cells using recombinant human Notch3-ICD protein and protein interaction arrays.

We have identified several novel Notch3-ICD interacting proteins. Among them, we focused on characterizing WW domain containing E3 ubiquitin protein ligase 2 (WWP2), a member of the NEDD4 family of ubiquitin-protein ligases. We found that WWP2 specifically co-immunoprecipitated with Notch3-ICD but not with Notch1-ICD, and ubiquitinated Notch3-ICD, leading to its degradation in lysosomes. Overexpression of WWP2 in OVCAR3 cells reduced Notch3 steady state protein levels, suppressed Notch3 reporter activity, and inhibited cellular proliferation. On the other hand, a dominant negative isoform of WWP2, as well as knockdown WWP2 using shRNAs, prevented ubiqutination of Notch3-ICD, increased Notch3-ICD protein levels, and enhanced Notch3 reporter gene activity. Compared to their normal counterparts, including fallopian tube and ovarian surface epithelial cells, OSC cell lines and tissues had a significantly lower mRNA and protein levels of WWP2 while Notch3 protein expression was inversely correlated with WWP2 expression levels. The above results provide new evidence that WWP2 protein is a key regulator of Notch3-ICD protein expression levels in ovarian cancer cells. WWP2 modulates Notch3 signaling activity by regulating its degradation pathway and downregulation of WWP2 may represent a novel mechanism to activate the Notch3 signaling pathway in cancer.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1987. doi:10.1158/1538-7445.AM2011-1987
Abstract 1990: GNMT activates mTOR/Raptor signaling and delays G2/M progression through interacting with DEPTOR
Authors: Yen Chia-hung , Lu Yao-Cheng , Li Chung-Hsien , Lee Cheng-Ming , Chen Chia-Yen , Cheng Ming-Yuan , Huang Shiu-Feng , Lee Yan-Hwa Wu , Chen Yi-Ming A.
Published: August 2014

GNMT is a tumor suppressor for hepatocellular carcinoma (HCC). We found that DEPTOR, a novel mTOR binding protein, interacts with GNMT through its PDZ domain. DEPTOR expression is significantly increased in HCC, especially among patients with HCV infection. Loss of DEPTOR in HuH-7 cells activates S6K but reduces Akt activation and cell growth. DEPTOR overexpression activates Akt and extends survival of HCC cells. Overexpression of GNMT counteracts DEPTOR induced Akt activation and activates mTORC1 downstream signaling via disruption of the DEPTOR-mTOR interaction. Moreover, GNMT overexpression delays G2/M progression, which causes senescence and slows proliferation of HuH-7 cells, sensitizing them to rapamycin. We suggest that GNMT by interacting with DEPTOR regulates the cellular homeostasis of hepatocytes through modulation of Akt/mTORC1 signaling.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1990. doi:10.1158/1538-7445.AM2011-1990
Abstract 1993: Interaction between histone demethylase and deacetylase may mediate activity of HDAC inhibitors in human breast cancer cells
Authors: Huang Yi , Vasilatos Shauna N. , Boric Lamia , Shaw Patrick G. , Davidson Nancy E.
Published: August 2014

Histone acetylation and methylation are two important epigenetic entities that interact with each other in chromatin remodeling and gene transcription regulation. It has been shown that abnormal activities of histone lysine deacetylases (HDACs) and histone lysine demethylases (KDMs) are associated with aberrant gene expression in cancer development. However, the precise molecular mechanisms underlying the crosstalk between HDACs and KDMs are still elusive. In this study, we showed that exposure of human breast cancer MDA-MB-231 and MDA-MB-468 cells to inhibitors against the zinc cofactor dependent class I or II HDACs, but not NAD+ dependent class III HDAC, led to significant increases of global di or mono-methylation of histone 3 lysine 4 (H3K4me2/me1) which are specific substrates of histone lysine-specific demethylase 1 (LSD1) and key positive chromatin marks promoting transcriptional activation. HDAC inhibitors did not affect in vitro demethylation activity of recombinant LSD1 and did not alter the nuclear presence of the LSD-CoREST-HDAC1/2 complex, indicating the inhibition of LSD1 activity in breast cancer cells by specific HDAC inhibitors likely occurs through disrupting the functional interaction between LSD1 and HDACs rather than direct competition with enzymatic substrate at the active site of LSD1 or suppression of LSD1 protein levels. Inhibition of LSD1 activity by its inhibitor, pargyline, or RNAi in MDA-MB-231 cells caused an increase in acetylation of H3K9 (AcH3K9), suggesting that LSD1 is an important regulator of HDAC activity in breast cancer. Chromatin immunoprecipitation (ChIP) demonstrated that LSD1/HDAC repressive complex is recruited to the promoter of one candidate target gene, estrogen receptor alpha (ERα), in ER negative breast cancer cells and the reactivation of silenced ERα by HDAC inhibitor is associated with increased H3K4me2, acetylH3K9 and acetylH4K16 at ERα promoter. In addition, combined treatment with HDAC inhibitors and the LSD1 inhibitor, pargyline, resulted in enhanced levels of H3K4me2 and AcH3K9, and synergistic growth inhibition of MDA-MB-231 cells. These data suggest a crosstalk between the histone demethylase, LSD1, and histone deacetylases as a novel regulatory mechanism in mediating activity of HDAC inhibitors and may help in designing combinations that could have significant clinical translation in breast cancer therapy.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1993. doi:10.1158/1538-7445.AM2011-1993