bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 951: Preclinical evaluation of Xanthohumol in carcinoid cancer growth in vitro and in vivo
Authors: Kunnimalaiyaan Muthusamy , Ndiaye Mary , McManus Catherine M. , Seiler Nicole L. , Harrison April , Chen Herbert
Published: August 2012

Background: Besides surgery, there is no potential curative treatment for carcinoid tumors. Because these cancers are metastatic in nature and produce excessive amounts of various bioactive hormones, patients diagnosed with this malignancy will have poor quality of life due to carcinoid syndrome. Therefore, new anticarcinogenic agents are required to improve the effectiveness of treatment. Xanthohumol (XN) (Tetrahydroxy-3′-prenylchalcone) is a prenylated chalconoid found in hops and beer that has been found to have potential anticancer and bioactive properties. Therefore, the purpose of this study was to evaluate the effectiveness of xanthohumol (XN) on carcinoid cancer growth in vitro and in vivo. Methods: To examine the anticancer activity of XN, we treated human gastrointestinal carcinoid BON and bronchopulmonary carcinoid H727 cells with up to 15 μmol/L of XN or carrier (DMSO), and analyzed the effect on cell growth by colony formation assay. The mechanism of growth inhibition was examined by flow cytometry and western analysis for the levels of pro-apoptotic and cell cycle regulatory proteins. To examine the anticancer activity of XN in vivo, subcutaneous BON carcinoid tumors developed in murine xenografts were subjected to intraperitoneal injections of XN (3 mg/kg bwt) or an appropriate volume of DMSO carrier every other day. Results: Treatment with xanthohumol significantly reduced the ability of carcinoid cells to form colonies in a dose-dependent manner. Flow cytometry and western analysis confirmed the observed decrease in cell viability, and showed the decrease was mediated through apoptosis. The carcinoid tumors in the mouse xenograft experiment showed a significant reduction in growth. Conclusions: XN treatment reduced cell viability, colony forming ability and increased cell death through apoptosis. In addition, administration of XN suppressed cancer cell growth in an in vivo xenograft mouse model. Our findings demonstrate for the first time the anti-proliferative effects of xanthohumol in carcinoid cell lines in vivo. Xanthohumol is already being used as a dietary supplement to encourage overall health and has shown few side effects. This fact combined with the potential anticarcinogenic activity found here warrants clinical investigation on patients with carcinoid disease.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 951. doi:1538-7445.AM2012-951
Abstract 953: Therapeutic significance of estrogen receptor ≤ agonists in gliomas
Authors: Sareddy Gangadhara Reddy , Nair Binoj C. , Gonugunta Vijaya K. , Zhang Quan-guang , Brann Darrell W. , Tekmal Rajeshwar Rao , Vadlamudi Ratna K.
Published: August 2012

Purpose: Gliomas are the most common type of primary brain tumors with bleak prognosis. Gliomas exhibit gender bias with females at lower risk than males, implicating estrogen mediated protective effects. Estrogen functions are mediated by two ER subtypes: ERbeta, that functions as tumor promoter and ERbeta that function as tumor suppressor. In this study, we examined the status of ERbeta and tested whether natural ERbeta agonists have therapeutic potential on gliomas. Experimental Design: Tumor microarrays (TMAs) were utilized to determine the levels of ERbeta in gliomas. Therapeutic effect of three ERbeta agonists was determined using proliferation, foci formation and cell cycle progression assays. Functionality of ERbeta signaling in gliomas was determined by reporter assays and localization by confocal microscopy. The therapeutic potential of liquiritigenin was determined by systemic administration in a glioma xenograft model. Results: TMA analysis revealed that ERα expression is down regulated in high-grade gliomas. Glioma model cells exhibited detectable ERα with functional ERα signaling. Treatment of glioma cells with ERα agonists resulted in significant decreases in proliferation. Further, ERbeta agonist treatment induced the expression of ERα. Compared to control mice, animals treated with liquiritigenin had 50% reduction in tumor volume and size. IHC analysis of tumors revealed a significant increase in the nuclear ERα expression with a concomitant decrease in cell proliferation in the liquiritigenin-treated group. Conclusion: We found that ERα agonists promote both expression and tumor suppressive functions of ERα. Liquiritigenin, a plant-derived ERα agonist significantly reduced in vivo tumor growth in a xenograft model. Our results suggest that ERα signaling has a tumor suppressive function in gliomas and thus ERα agonists may represent a novel class of drugs for curbing glioma progression. Since ERα agonists are currently in clinical trials and are well tolerated with fewer side effects, identification of an ERα agonist as a therapeutic agent can be readily extended to clinical use with current chemotherapies, providing an additional tool for enhancing survival in glioma patients.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 953. doi:1538-7445.AM2012-953
Abstract 955: Role of cMYC as a critical determinant of estrogen-independent growth of estrogen deprivation-resistant breast cancer cells
Authors: Sengupta Surojeet , Biarnes Michael C. , Jordan V Craig
Published: August 2012

Around two-third of all breast cancers express estrogen receptor alpha (ER), which depend upon estrogen for proliferation of the ER positive breast cancer cells. Aromatase inhibitors (AI) are used extensively to treat postmenopausal patients, which block the synthesis of estrogen and render an “estrogen-deprived” environment. Unfortunately, long-term treatment with AIs is associated with “AI-resistant” breast cancers, which by-passes the dependency on estrogen for the growth of the resistant breast cancer cells. To mimic these resistant breast cancers we have developed an estrogen-deprivation (ED) resistant cell line known as MCF7:5C cells from the parental ER positive MCF7 cells by propagating them in estrogen-free conditions for more than a year. MCF7:5C cells are ER positive and grow spontaneously in vitro as well as form xenograft tumors in the athymic mice in absence of estrogen (ref: Lewis et al., JNCI, 2005; 97(23):1746-59). To understand the underlying mechanism and identify the molecular determinant responsible for the estrogen-independent growth of these breast cancer cells we found that a critical estrogen-regulated gene, cMYC, is upregulated in these ED-resistant MCF7:5C cells. Basal levels of cMYC mRNA as well as the protein level were elevated three to four fold as compared to parental MCF7 cells which are dependent on estrogen for growth. Cell cycle analysis revealed twice as many “S” phase MCF7:5C cells as compared to MCF7 cells under basal condition. Treating the cells with a cMYC inhibitor, 10058-F4, decreased the number of ‘S’ phase cells and increased the cells in ‘G1′ phase in MCF7:5C cells but not in parental MCF7 cells, in a dose dependent manner. Interestingly, treatment with fulvestrant, a complete anti-estrogen, which inhibits the growth of the MCF7:5C cells by 50% also decreased the cMYC mRNA levels by similar extent. To understand the precise mechanism by which high levels of cMYC transcripts are synthesized in MCF7:5C cells we investigated the promoter of the cMYC gene and found that under basal conditions the recruitment of phosphor-serine-2-RNA polymeraseII, which is a marker of RNA elongation, was significantly higher in MCF7:5C cells as compared to the parental MCF7 cells. This study strongly indicates cMYC as a critical determinant responsible for estrogen-independent growth of ED-resistant breast cancer cells. Grant Support: This work (VCJ) was supported by the Department of Defense Breast Program under Award number W81XWH-06-1-0590 Center of Excellence; the Susan G Komen For The Cure Foundation under Award number SAC100009.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 955. doi:1538-7445.AM2012-955
Abstract 956: The liver-X-receptor-α is involved in the induction by Tamoxifen of breast cancer cell differentiation and death
Authors: Segala Gregory , de Medina Philippe , Paillasse Michael , Jordan V. Craig , Silvente-Poirot Sandrine , Poirot Marc
Published: August 2012

Hormonotherapy with Tamoxifen (Tam) is one of the main strategies used world-wide for the treatment of estrogen receptor positive breast cancer. However, partial responses, tumor recurrence and acquired resistance to Tam may involve mechanisms unrelated to Estrogen Receptors (ER). Studies on non-ER related mechanisms of action of Tam led us to find that it induced breast cancer cell differentiation and death through the modulation of sterol metabolism and the stimulation of sterol oxidation (de Medina et al, Cell Death Differ, 2009), and that Tam inhibited cholesterol epoxide hydrolase (ChEH). ChEH catalyzes the trans hydration of cholesterol-5,6-epoxides (CE) and this activity is a property of the microsomal antiestrogen binding site (AEBS) (de Medina et al, PNAS, 2010). In the present study we report that Tam and AEBS ligands stimulated the oxidation of cholesterol into CE and induced the accumulation of CE in MCF-7 cells through the inhibition of ChEH at therapeutic concentrations. Since CE has been reported to be a modulator of Liver-X-Receptors (LXR), we investigated the impact of Tam and other AEBS ligands on LXR-dependent gene expression: Tam and AEBS ligands modulated the expression LXR-dependent genes in MCF-7 cells. This effect had a 24 to 48 hour lag time while the effect of direct LXR modulators was observable after 6 hours, suggesting an indirect action of AEBS ligands. The involvement of CE in the control of transcription by Tam and AEBS ligands was supported by the observation that vitamin E, which inhibited the formation and the accumulation of CE, totally blocked this transcriptional modulation. We found that knocking down LXR-α using interfering RNAs in MCF-7 cells blocked the transcriptional modulation of LXR-controlled genes induced by CE, Tam and AEBS ligands. Finally, we found that the knock down of LXR-α reproduced the vitamin E inhibition of the induction of differentiation and death of MCF-7 cells. Altogether, these data showed that LXR-α is implicated in the anticancer action of Tam and identified a new signaling pathway that could explain sensitivity and resistance to Tam.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 956. doi:1538-7445.AM2012-956
Abstract 975: Employing functional genomics to reveal emergent dependencies
Authors: Cappell Kathryn , When Amy , Taus Patrick , Maxfield Kimberly , Whitehurst Angelique
Published: August 2012

Using a pangenomic loss of function strategy, our group has recently discovered that a cohort of gametogenic genes modulates chemoresponsiveness in tumor cells. Numerous studies focused on identifying aberrant gene expression patterns in tumors have previously correlated the presence of gametogenic genes with the tumorigenic state. Our functional genomics approach has now revealed that these tumor-activated aberrant gene products may play essential roles in supporting tumor cell fitness in the presence of insults, such as genotoxic stress. Specifically, depletion of each of the 8 gametogenic genes identified in our screen results in an increase in mitotic transit time and a reduction in mitotic fidelity in the presence of paclitaxel, demonstrating a requirement for their function at the level of chromosome segregation. At the cell biological level, these components contribute to mitotic spindle architecture by supporting centrosomal coalescence, centrosome duplication and/or microtubule stability. Given that the expression of these genes is otherwise biased towards the germline, they could present pharmacological entry points with an extraordinary therapeutic window. For example, we find that the CT-antigen, ACRBP, specifies poor outcome in ovarian patients and depletion of ACRBP can enhance sensitivity to paclitaxel in ovarian tumor explants in vitro and an ovarian orthtopic xenografts in vivo. In addition, we find that a small molecule that targets the gametogenic protein, TACC3, synergizes with paclitaxel to reduce tumor cell growth. We propose that the dependency on these gametogenic components may arise as a consequence of passage through a selection bottleneck, during tumor evolution, which requires acquisition of traits that normalize the mitotic perturbations originally driving the plasticity of preneoplastic genomes. We show that such traits, when defined by otherwise anomalous gene products, may represent conceptually ideal intervention targets with wide therapeutic windows.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 975. doi:1538-7445.AM2012-975
Abstract 982: Malate dehydrogenase 2 confers resistance to docetaxel chemotherapy in prostate cancer through JNK pathway
Authors: Liu Qiong , Geng Hao , Xue Changhui , Beer Tomasz , Qian David Z.
Published: August 2012

Resistance to chemotherapy represents a significant obstacle in cancer therapeutics. Novel mechanistic understandings in cancer cell chemotherapeutic sensitivity and resistance can optimize treatment and improve patient outcome. Molecular alterations in the metabolic pathways are associated with cancer development; however, the role of these alterations in chemotherapy efficacy is largely unknown. In this study, we identified a novel role for mitochondrial malate dehydrogenase 2 (MDH2) in mediating prostate cancer resistance to docetaxel-chemotherapy. We performed gene expression microarray analyses on frozen needle biopsies from prostate cancer patients before they underwent neoadjuvant chemotherapy. We observed that genes in the metabolic pathways are significantly altered in the cancer epithelium versus the matched- tumor adjacent benign epithelium. In addition, some of the metabolic gene expression alterations are associated with the long-term treatment outcome. Patients with MDH2 overexpression in cancer cells had a significantly lower relapse-free survival (RFS) based on the Kaplan-Meier analysis. To investigate the underlying mechanism responsible for this clinical observation, we found that MDH2 expression was elevated in prostate cancer cell lines compared to benign prostate epithelial cells. Then we established stable MDH2 knock-down prostate cancer lines and evaluated cell proliferation and cell viability within the context of chemotherapy. We found that MDH2 knockdown significantly enhanced the docetaxel sensitivity in prostate cancer cell lines LNCaP, C42B and PC3. Metabolic and redox measurement showed that MDH2 knockdown significantly reduced cellular ATP levels and increased the ADP/ATP and NAD+/NADH level. In addition, MDH2 knockdown significantly increased reactive oxygen specifies (ROS) while maintaining the oxygen consumption rate. These metabolic alterations were associated with the sustained activation of JNK signaling cascade after docetaxel treatment and the inactivation of apoptosis inhibitor BCL2. Taken together, these data suggest a novel function for MDH2 in prostate cancer development and chemotherapy, in which the cancer associated metabolic and redox alteration confers resistance to chemotherapy by regulating pathways of signal transduction and cell death.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 982. doi:1538-7445.AM2012-982
Abstract 986: Reverse-engineered, forward-simulation of MEK-dependent molecular networks reveal novel regulators of cell cycle and cancer cell survival
Authors: Gendelman Rina , Xing Heming , Sarde Preeti , Mirzoeva Olga K. , Feiler Heidi , Gray Joe W. , McDonagh Paul , Khalil Iya , Michael W.
Published: August 2012

ABSTRACT Molecular networks governing responses to targeted therapies in cancer cells are complex dynamic systems that demonstrate non-intuitive behaviors. We applied a novel computational strategy to decipher causal relationships between signaling network components. Gene networks were constructed MEK from global gene expression profiles to model G1-S cell cycle arrest as a consequence of inhibition of MEK, a key component of the oncogenic RAF-MEK-ERK signal transduction pathway. Through forward-simulation of reverse-engineered networks candidate MEK-dependent regulators of the cell cycle were identified. The potential of the approach to infer causality is demonstrated by confirmed predictions of differential effects of two early-response transcription factors, IER2 and EGR1. Conventional linear regression analysis shows strong correlation of expression of both with MEK inhibition and cell cycle distribution, while only IER2 is predicted by our model and experimentally validated to have a causal effect on G1-S transition. Furthermore, we identify TRIB1 (tribbles homologue 1 drosophila) as a potent and novel cell cycle regulator. TRIB1 also mediates cross-talk to the NFkB pathway by enhancing p100 and IkBa-phosphorylation and degradation thus regulating cell survival and expression of cytokines crucial for tumor-stroma interaction. In agreement with this, knock-down of TRIB1 results in induction of apoptosis and sensitizes cells to cell killing induced by the death-receptor agonist TRAIL via upregulation of TRAIL receptor, DR5. Thus TRIB1 is a central regulator of cell cycle and survival and represents a potential therapeutic target.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 986. doi:1538-7445.AM2012-986
Abstract LB-10: Distribution and potency of anti-proliferative arachidonic acid metabolites
Authors: Revello Sonia D. , Snyder Nathaniel W. , Liu Xiaojing , Zhang Suhong , Arora Jasbir S. , Blair Ian A.
Published: August 2012

Eicosanoids participate in the dysregulation of cell proliferation during tumorigenesis. The up-regulation of cyclooxygenase-2 (COX-2) and down-regulation of 15-prostaglandin dehydrogenase (15-PGDH) have been linked to the switch for a pro-proliferative and pro-angiogenic tumor microenvironment. Previous studies have characterized the effects of increased prostaglandin E2 in tumor progression but the role of many other endogenous lipid mediators has yet to be determined. COX-2 can metabolize arachidonic acid (AA) to hydroxyeicosatetraenoic acids (HETEs), which in turn can be further oxidized by dehydrogenases into oxo-eicosatetraenoic acids (oxo-ETEs). We have previously reported that 11-oxo-ETE and 15-oxo-ETE are major COX-2/15-PGDH derived metabolites formed from human cells expressing COX-2 treated with AA. Although no known G-protein coupled receptor has been reported for either of these metabolites, both 11-oxo- and 15-oxo-ETE have been described from human clinical samples. This study provides a description of the uptake and distribution of 11-oxo-ETE and 15-oxo-ETE as well as their anti-proliferative activity in both human umbilical vein endothelial cells (HUVECs) and LoVo human colon adenocarcinoma cells. Quantification of the intracellular and extracellular levels of 11-oxo- and 15-oxo-ETE was conducted using liquid chromatography electron capture atmospheric pressure chemical ionization mass spectrometry with [13C]-labeled 15-oxo-ETE as an internal standard. The intracellular concentrations of 11-oxo- and 15-oxo-ETE reached peak amounts within 1h followed by a rapid decline. Earlier studies have indicated that glutathione (GSH)-S-transferase further metabolized 11-oxo-ETE to form the 11-oxo-ETE-GSH (OEG)-adduct. In additional experiments, pretreatment with ethacrynic acid (EA), a known inhibitor of GSTs, increased recovery from the cellular extract. In addition, the methyl-ester of both 11-oxo- and 15-oxo-ETE was used for the targeted intracellular delivery of these COX-2/15-PGDH derived eicosanoids. Finally, we have shown that both 11-oxo- and 15-oxo-ETE as well as their methyl ester derivatives significantly inhibit cell proliferation as determined by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) cell proliferation assay and Bromodeoxyuridine (BrdU) incorporation in multiple human cell lines. The present study has established the cellular uptake of the short-lived COX-2/15-PGDH derived eicosanoids 11-oxo- and 15-oxo-ETE and potent inhibition of new DNA synthesis and proliferation.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr LB-10. doi:1538-7445.AM2012-LB-10
Abstract LB-109: MDV3100, an androgen receptor signaling inhibitor, inhibits tumor growth in breast cancer preclinical models regardless of estrogen receptor status
Authors: Cochrane Dawn R. , Jacobsen Britta M. , Cittelly Diana M. , Howe Erin N. , Jean Annie , Spoelstra Nicole S. , Bernales Sebastian , Protter Andrew A. , Elias Anthony D. , Richer Jennifer K.
Published: August 2012

Background: The androgen receptor (AR) is detected by immunohistochemistry in approximately 75% of all invasive breast cancer, with ∼88% of estrogen receptor (ER) positive (ER+) tumors also expressing AR and ∼20 to 30% of ER negative (ER-) tumors also retaining AR expression. Potent inhibition of AR activity could be a therapeutic strategy in AR+ ER+ breast cancer. MDV3100 is an androgen receptor signaling inhibitor (ARSI), which inhibits AR activity via three mechanisms: 1) inhibition of androgen binding to AR, 2) inhibition of AR nuclear translocation, and 3) inhibition of nuclear AR-DNA binding; and has demonstrated an overall survival benefit in men with post-docetaxel prostate cancer. Methods: Two ER+/AR+ breast cancer cell lines, MCF7and BCK4 (recently derived from a pleurocentesis), were used to assess the proliferative effect of dihydrotestosterone (DHT) and estradiol (E2) in ovariectomized mice. MDV3100 was compared to bicalutamide and tamoxifen. Growth effects of MDV3100 on ER-/AR+ cells in tissue culture and in xenografts were also examined. Results: Both bicalutamide and MDV3100 inhibited DHT-mediated proliferation of ER+/AR+ cell lines. Although MDV3100 binds AR very effectively and does not bind ER, it inhibited E2-mediated proliferation. MDV3100 also blocked E2 mediated upregulation of AR, PR, and SDF-1. MDV3100 inhibited E2-stimulated tumor growth of MCF7 mammary xenografts as effectively as tamoxifen. With ER-/AR+ cells (MDA-MB-453), MDV3100 reduced DHT-induced nuclear translocation, cell growth in tissue culture and tumor growth in mouse orthotopic xenografts. Conclusions: MDV3100 blocked both DHT- and E2-mediated growth of breast cancer cells, whereas bicalutamide enhanced E2-mediated proliferation. MDV3100 may have unique therapeutic utility in patients with AR+ breast cancer, regardless of ER status. Funding: DOD Breast Cancer Program Idea Award BC074403, Avon Foundation for Women, and University of Colorado Cancer Center pilot project funds to JKR.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr LB-109. doi:1538-7445.AM2012-LB-109
Abstract LB-112: Ex vivo lung cancer nodule model shows efficacy of nanoparticle delivery
Authors: Mishra Dhruva K. , Shen Haifa , Mai Junhua , Ott Harald C. , Baird Brandi N. , Kurie Jonathan M. , Kim Min P.
Published: August 2012

Nanoparticles have the potential of being used for treatment of lung cancer. However, it is difficult to determine how nanoparticles target cancer cells in a poorly vascularized tumor nodule. In our study, we hypothesize that we can develop an ex vivo human lung cancer nodule model with a perfusable vascular bed that can be used to test distribution of nanoparticles. To create this ex vivo human lung cancer nodule model, we isolated the rat heart-lung block from a 6-week-old Sprague-Dawley rat. We then removed the native rat cells from the lung using sodium dodecyl sulfate and Triton-X-100 in a customized decelluarization chamber. We then placed human lung cancer cell lines H460 and H1299 through the trachea of the acellular rat lung scaffold in a bioreactor. After three days of growth in the bioreactor, we placed 700 million nanoparticles into the scaffold through the circulation labeled with fluorescent tags. We performed lobectomy 1 and 3 days following placement of the nanoparticles. We examined the distribution of the nanoparticles in the nodules using hematoxylin and eosin (H&E) stain and confocal microscopy. There were numerous tumor nodules on both lung scaffolds, measuring 2 mm, three days after placement of the cells. One day after placement of the nanoparticles the lobectomy specimen on the H&E showed that the scaffold with H460 cells had features of poorly differentiated non-small cell lung cancer with sheet-like growth of polygonal cells and the scaffold with H1299 cells had features of very poorly differentiated malignant cells. Moreover, most of the nanoparticles were distributed along the vascular structures with paucity of nanoparticles in the center of the tumor nodules. The confocal microscopy showed that in some areas, nanoparticles were found inside the cytoplasm and nucleus of the cells. Three days after the placement of the nanoparticles, the H&E showed increased number of cells in the tumor nodules with uptake of nanoparticles. Given these results, we believe that the ex vivo human lung cancer nodule model can be used to show delivery of nanoparticles in a complex nodule and determine its efficacy. This can aid in determining appropriate dose of nanoparticles, design of nanoparticles and efficiency of delivery of nanoparticles to heterogeneous tumor nodules, which would aid in vivo treatment studies.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr LB-112. doi:1538-7445.AM2012-LB-112
Abstract LB-155: Smad4 negatively regulates beta-catenin signaling through proteasomal degradation of Aurora A in human cancer cells
Authors: Jia LIina , Lee Hun Seok , Park Sang Gyu , Kundu Juthika , Shin Young Kee
Published: August 2012

Aurora kinase A (AURKA), a centrosomal serine/threonine protein kinase, is frequently over-expressed in a wide range of human cancers. In the present study, we showed that the expression of AURKA is downregulated in human cancer cells upon over-expression of the tumor suppressor protein Smad4. Bimolecular Fluorescence Complementation (BiFC) assay revealed that full-length Smad4 and linker region interacts with C terminal (kinase domain) domain of AURKA. Ectopic expression of Smad4 down-regulated the expression of AURKA and attenuated phosphorylation of glycogen synthase kinase-3β (GSK3β) at serine-9 residue in HeLa and AGS cells, which resulted in the reduced protein expression and the transcriptional activity of β-catenin. Pre-incubation with MG132 abrogated the degradation rate of AURKA in Smad4 over-expressing HeLa and AGS cells. Conversely, silencing of Smad4 in HeLa cells up-regulated the expression of AURKA and inactivated GSK3β, and subsequently increased the expression of β-catenin. In addition, transient over-expression of Smad4 in Smad4-deficient SW480 colon cancer cells diminished the expression of AURKA and negated GSK3β phosphorylation, resulting in the reduced protein expression and the transcriptional activity of β-catenin. In contrast, siRNA-mediated silencing of AURKA in Smad4 over-expressed cells failed to alter the expression of β-catenin. Taken together, our study demonstrates that restoration of Smad4 inhibits tumor progression by blocking AURKA -mediated signaling.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr LB-155. doi:1538-7445.AM2012-LB-155
Abstract LB-165: The role of sphingolipid metabolism in the treatment of acute myeloid leukemia
Authors: Smith Eric L. , Schuchman Edward , Hoffman Ronald
Published: August 2012

While significant progress has been made in understanding the genetics of AML, treatment still consists of induction therapy that is toxic and not tolerated by the elderly. In this study we show in cell culture models that manipulating sphingolipid metabolism may provide a potential mechanism to increase the efficacy of induction therapy, thus possibly allowing the use of lower doses of cytotoxic chemotherapy while maintaining efficacy. Recently thousands of papers have revealed that sphingolipid metabolism has a major role in determining how a diverse group of cell types, including myeloid malignancies, respond to a variety of stresses, particularly chemotheraputics, through production of the pro-apoptotic lipid ceramide. Conversely, a downstream ceramide metabolite, sphingosine-1-phosphte (S1P), has been shown to have the opposite effect, promoting survival, multi-drug resistance, and proliferation. We hypothesize that through the use of small molecules that inhibit the metabolism of ceramide and the formation of S1P we can decrease the apoptotic threshold of leukemic cells. To investigate this we used inhibitors to two enzymes that metabolize ceramide, the ceramidase inhibitor, LCL-385, and the glucosylceramide synthase inhibitor, PDMP, as well as the sphingosine kinase inhibitor, SKI, alone and in combination with daunorubicin and cytarabine in common AML cell culture models, HL-60 and HEL. We found that at low nanomolar concentrations each of these inhibitors alone dramatically decreases proliferation and increases apoptosis in both cell types in a dose dependant manner. Most importantly, through analysis with the Chou and Talalay combination index model, we have shown that each of these molecules works synergistically with daunorubicin and cytarabine (see table below). This data highlights the importance of sphingolipid metabolism in the response of AML cells to chemotherapy and as a potential synergistic target for induction therapy.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr LB-165. doi:1538-7445.AM2012-LB-165
Abstract LB-167: Prepubertal or lifetime genistein intake reduces risk of tamoxifen resistance in rats
Authors: Zhang Xiyuan , Warri Anni , Cruz Idalia M. , Cook Katherine , Clarke Robert , Hilakivi-Clarke Leena
Published: August 2012

Using a preclinical model, we studied whether consumption of soy isoflavone genistein (GEN) during childhood modifies the effect of adult GEN intake on the ability of tamoxifen (TAM) to inhibit mammary tumor growth. Female rats were fed AIN93G control diet supplemented with 0 or 500 ppm genistein between postnatal days (PND) 15 and 30 (prepubertal exposure); on PND30 both groups received control diet. They were then exposed on PND50 to DMBA, and on PND57 divided to four dietary groups (n=20-40 per group) (see Table). Most rats in all four groups developed mammary tumors, but tumor latency was longer in the prepubertally GEN fed G-G (P<0.003) and G-C groups (p<0.095), compared to controls. TAM treatment (338 ppm in the diet) was started when tumor reached a size of 1.4 cm, and rats were followed for 18 weeks. The response to TAM was determined as complete response (CR), partial response (PR), or as being resistant. Adding GEN to the diet when TAM treatment started increased TAM resistance by 48%, compared to rats which were never fed GEN. Adult GEN intake (C-G group) further reduced CR. However, protein levels in the tumors of genes involved in unfolded-protein response and associated with TAM resistance (IRE1a, BIP, ATF4, BECLIN1, CHOP, ER), were not affected. Prepubertal GEN intake in G-C and G-G groups significantly increased the rate of CR and inhibited TAM resistance. Total tumor burden, which reflects the response of all tumors per rat to TAM, including those appearing during TAM treatment (de novo TAM resistant) was significantly higher in the rats which received GEN as adults, compared to the other three groups (p<0.001); lowest tumor burden was seen in the rats which consumed GEN both during prepuberty and as adults. Our findings suggest that prepubertally GEN fed rats, also when they continue to consume GEN in adulthood, are at low risk of developing TAM resistance. In contrast, adult only GEN consumption significantly impaired response to TAM. Mechanisms explaining these data are currently being investigated.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr LB-167. doi:1538-7445.AM2012-LB-167
Abstract LB-169: Metformin reduces somatic cell mutation rate by inhibiting mitochondrial ROS production: relevance to cancer prevention
Authors: Pollak Michael N. , Algire carolyn , Ferbeyre Gerardo
Published: August 2012

Pharmacoepidemiological studies provide evidence that use of metformin, a drug commonly prescribed for type II diabetes, is associated with a substantial reduction in cancer risk. Experimental models show that metformin inhibits the growth of certain neoplasms by cell autonomous mechanisms such as activation of AMP kinase with secondary inhibition of protein synthesis, or by an indirect mechanism involving reduction in gluconeogenesis leading to a decline in insulin levels and reduced proliferation of insulin-responsive cancers. Here we show that metformin attenuates paraquat-induced elevations in reactive oxygen species (ROS), DNA damage and mutations, but has no effect on similar changes induced by H202, indicating a reduction in endogenous ROS production. Metformin also inhibited Ras-induced ROS production and DNA damage. Our results reveal previously unrecognized inhibitory effects of metformin on ROS production and somatic cell mutation, providing a novel mechanism for the reduction in cancer risk associated with exposure to this drug.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr LB-169. doi:1538-7445.AM2012-LB-169
Abstract LB-172: MicroRNAs mediate the inhibition of tumor cell invasion by sulindac
Authors: Li Xiaobo , Gao Lin , Taylor William , Shevde Lalita , Samant Rajeev , Dean-Colomb Windy , Piazza Gary A. , Xi Yaguang
Published: August 2012

A large body of evidence indicates that nonsteroidal anti-inflammatory drugs (NSAIDs) have strong antineoplastic properties against a broad range of cancer types in early or late stage animal models of tumorigenesis. However, their use in humans for chemoprevention is limited by toxicities resulting from cyclooxygenase (COX) inhibition and the suppression of physiologically important prostaglandins. The anticancer properties of NSAIDs are generally attributed to the suppression of tumor cell proliferation and induction of apoptosis by inhibiting cyclooxygenase (COX), although numerous studies suggest that a COX-independent mechanism may either contribute to or be fully responsible for their activity. The effect of NSAIDs on tumor cell motility and invasion has not been well studied, despite clinical studies showing that certain NSAIDs can significantly increase the survival of patients with metastatic disease. Our results show that the NSAID, sulindac sulfide (SS) can potently inhibit the motility of human breast (MDA-MB-231 and SUM1315) and colorectal (HCT116 and HT29) tumor cells by a mechanism that is distinct from its tumor cell growth and COX inhibitory activity. To study the molecular basis for this activity, we investigated the involvement of microRNA (miRNA). A total of 132 miRNAs were found to be altered in response to SS treatment including miR-10b, miR-17, miR-21, and miR-9, which have been previously implicated in tumor invasion and metastasis. We confirmed that these miRNAs can stimulate tumor cell invasion and show that SS can attenuate their invasive effects (individual and cooperative) by down-regulating their expression. Employing luciferase and chromatin immunoprecipitation (ChIP) assays, NF-κB was found to bind the promoters of all four miRNAs to regulate their expression at the transcriptional level. Results from the immunofluorescence and Western Blotting assays show that SS can inhibit the translocation of NF-κB to the nucleus by decreasing the phosphorylation of IKKβ and IκB, which leads to down-regulation of these miRNAs. Analysis of the promoter sequences of the miRNAs suppressed by SS revealed that 81 of 115 sequences contained NF-κB binding sites. Our results demonstrate that SS can inhibit tumor cell invasion by suppressing NF-κB mediated transcription of miRNAs, which illustrate the mechanistic basis of this novel anticancer property of sulindac on tumor progression and metastasis. We expect these results are capable of supporting future clinical trials of sulindac in patients with metastatic disease.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr LB-172. doi:1538-7445.AM2012-LB-172
Abstract LB-176: Chemoprevention of NNK-induced lung adenoma and adenocarcinoma in A/J mice by p53 modulating agents, CP-31398 and Prima-1
Authors: Rao Chinthalapally V. , Patlolla Jagan Mohan R. , Qian Li , Zhang Yuting , Brewer Misty , Mohammed Altaf , Desai Dhimant , Amin Shantu , Lightfoot Stan , Kopelovich Levy
Published: August 2012

Lung cancer is a leading cause of cancer deaths worldwide. p53 Mutations including wild-type p53 nuclear localization due to excessive endogenous electrophilic molecules are highly prevalent in tobacco associated lung cancers. Here, we report the chemopreventive effects of direct-acting p53 modulating agents, CP-31398 and Prima-1 on 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK)-induced lung adenoma and adenocarcinoma in female A/J mice. Seven weeks-old mice on a regular AIN-76A diet, received one dose of 10 μmol NNK /mouse by i.p. injection. Three weeks after NNK treatment, groups of mice (25 mice/group) were fed control AIN-76A or experimental diets containing 50 and 100 ppm CP-31398, or 150 and 300 ppm Prima-1. Mice were sacrificed after 20 weeks (10 mice/group) and/or 36 weeks (15 mice/group) following NNK-treatment and evaluated for lung adenomas and adenocarcinomas by histopathological methods. Administration of 50 and 100 ppm CP-31398 significantly suppressed lung tumor formation by 29% and 39.5% (P<0.01-0.0001), respectively after 20 weeks and 32.2% and 40.1% (P<0.01-0.0001), respectively after 36 weeks. Similarly, 150 and 300 ppm Prima-1 significantly suppressed lung tumor formation by 22.2% and 34% (P<0.04-0.0001) after 20 weeks and 28.8% and 47.4% (P<0.01-0.0001) after 36 weeks, respectively. Inhibition of NNK-induced lung adenocarcinoma by either agent was greater than 55-72% (p<0.0001) after 20 weeks and about 40-57% after 36 weeks. These results suggest that restoring/activating wild-type p53 function by small molecules significantly inhibits NNK-induced lung tumor in A/J mice, most notably delaying progression of adenomas to adenocarcinoma. IHC analysis of lung tumors from NNK-treated mice exposed to either CP-31398 or Prima-1 showed a significantly reduced proliferating cell nuclear antigen (PCNA)-positive index, increased accumulation of nuclear wt-p53 including increased p21 and TUNNEL positive cells compared to lung tumors from NNK-treated mice fed with control diet. Incidentally, neither COX-1 nor iNOS were significantly affected by CP-31398 or Prima -1 in the NNK derived lung tumors. These results demonstrate, for the first time, the chemopreventive role of p53 modulating agents on tobacco specific carcinogen-induced lung adenocarcinomas. {Supported by NIH, NCI grants NO1-CN-53300}.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr LB-176. doi:1538-7445.AM2012-LB-176
Abstract LB-180: Notch-1: A therapeutic target for breast cancer stem cells and breast cancer cells
Authors: Suman Suman , Das Trinath P. , Kurisetty Vittal , Gulappa Thippeswamy , Vadodkar Aditi Shirish , Lakshmanaswamy Rajkumar , Damodaran Chendil
Published: August 2012

In spite of early diagnosis and potent treatment modalities, breast cancer remains a leading cause of cancer related death among women. Studies have shown that breast cancer stem cells (BCSCs) are a subpopulation of tumor cells characterized by cell surface antigens CD44+/CD24-/low and high Aldehyde dehydrogenase (ALDH) enzyme activity. These cells are refractory to current treatment modalities, show higher risk of metastasis, a shorter time to recurrence, and relapse to death. Hence, it is imperative to find new effective treatments to target both BCSCs and breast cancer cells (BCs) in order to reduce mortality associated with this disease. Notch signaling is implicated in self-renewal of stem cells by transcriptional activation of its target genes such as Hes-1 and Hey-1. Hence, we screened small molecules, which target Notch signaling in ALDH+ and ALDH- breast cancer cells. We have identified a potent natural compound psoralidin that effectively inhibits ALDH+ and ALDH- breast cancer cells. Our results revealed, psoralidin significantly down-regulates Notch-1 and its target genes (Hes-1 and Hey-1), which resulted in growth inhibition and induction of apoptosis in both ALDH+ and ALDH- cells. Psoralidin significantly inhibited invasion and migration of ALDH+ (p<0.004) and ALDH- (p<0.001) cells. Interestingly, higher inhibition in invasion (MMPs, Laminin, ADAMs) and migration (E-cadherin, Vimentin, Snail, Slug, Zeb-1) was observed in case of ALDH- cells as compared to the ALDH+ cells. Our ongoing overexpression and inhibition studies on Notch-1 (in vitro and in vivo) may reveal the role of Notch-1 in ALDH+ and ALDH- cells. In addition, phenotypic and molecular analysis will help us to understand the mechanism behind tumor initiation, metastasis and recurrence of tumor growth in breast cancer. Our results may support psoralidin as a novel potent anticancer agent targeting both BCSCs and BCs.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr LB-180. doi:1538-7445.AM2012-LB-180
Abstract LB-195: Immune responses against cancer stem cell-specific tumor antigens and tumor microenvironment
Authors: Torigoe Toshihiko , Hirohashi Yoshihiko , Morita Reina , Nishizawa Satoshi , Yasuda Kazuyo , Takahashi Akari , Tamura Yasuaki , Sato Noriyuki
Published: August 2012

Cancer stem cell (CSC) is a small population of cancer cells with stem cell-like phenotype and highly tumorigenic capacity. It is known that they are resistant to conventional chemotherapy and radiotherapy, therefore being responsible for cancer recurrence and metastasis. However, it has been unclear if immune responses against CSCs can overcome the therapeutic resistance of CSCs. In this paper, I would like to present unique immunopathological properties of CSCs, including (1) anti-stress genes expressed preferentially in CSCs, (2) immune responses against CSC-specific tumor antigens and (3) tumor microenvironment modulated by CSCs. We could isolate CSCs from a variety of solid cancer cell lines such as breast, lung, colon, kidney, ovarium and endometrium cancer lines by using Hoechst33342 staining assay and ALDH1 activity assay. Comparative gene expression analysis using DNA microarray revealed a number of stress responsive genes that are preferentially expressed in CSCs such as genes encoding heat shock proteins (HSPs), stress-activated protein kinases, ABC transporters, oxidoreductases, and detoxification enzymes. Interestingly, some of them are expressed exclusively in testis among normal adult tissues. DNAJB8 was one of the CSC-preferential HSPs. RNAi-mediated knockdown of DNAJB8 could reduce the tumor forming capacity of CSCs, while its overexpression enhanced the tumorigenic capacity. Our findings account for the molecular basis of stress-resistant property of CSCs and highlight a novel strategy and molecular targets for CSC-specific cancer therapy. We next examined if immune responses against CSCs could be induced by immunization with CSC-specific gene products such as SOX2, DNAJB8 and OR7C1. CSC-specific cytotoxic T-cell clones were established from peripheral blood lymphocytes of cancer patients and we confirmed that CSCs were susceptible to T-cell-mediated cytotoxicity in vitro. Our data indicated that CSC antigens might serve as potent tumor vaccines for CSC-targeted immunotherapy. However, some CSCs had the property of immunoescape through modulation of tumor microenvironment. CSCs could recruit stromal cells that produced immunosuppressive cytokines. The role of stromal cells that interact with CSCs would be discussed.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr LB-195. doi:1538-7445.AM2012-LB-195