bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract LB-363: Inhibition of placental growth factor (PlGF) leads to regression of medulloblastoma
Authors: Snuderl Matija , Kirkpatrick Nathaniel D. , Walsh Elisa C. , Chung Euiheon , Kamoun Walid S. , Peterson Teresa E. , Munn Lance L. , Duda Dan G. , Fukumura Dai , Carmeliet Peter , Xu Lei , Jain Rakesh K.
Published: February 2011

Introduction: Medulloblastoma contains a rich and abnormal vascular network offering a potential target for anti-angiogenic treatment. However, in pediatric patients anti-VEGF treatments may have serious adverse effects and other antiangiogenic drugs have not shown efficacy. Placental growth factor (PlGF) is a mediator of post-natal pathological angiogenesis, and its inhibition may not be associated with significant side effects. Here, we examine the role of PlGF in medulloblastoma growth and as a target for therapy in this pediatric brain tumor.

Methods: Tissues collected from 5 pediatric medulloblastomas and 4 adult cerebelli were screened for 96 genes associated with angiogenesis using a commercially available PCR array. Immunohistochemistry was performed on 14 formalin fixed paraffin embedded (FFPE) medulloblastoma samples. D283Med and D341Med human medulloblastoma cells were transfected with Gaussia luciferase cDNA and implanted orthotopically into cerebelli of SCID mice. Tumor growth was followed by whole body imaging and blood Gluc assay. Tumor-derived PlGF was blocked by anti-PlGF antibody (PL5D11D4, ThromboGenics) or silenced by siRNA. WST-1 Cell Proliferation Assay was performed to explore direct effects of anti-PlGF Ab in vitro.

Results: PlGF was not expressed in adult cerebelli and was overexpressed in all medulloblastomas tissues and cell lines by PCR. Twelve of fourteen (85%) FFPE medulloblastomas showed expression of PlGF by immunohistochemistry. Mice with implanted medulloblastoma cells with PlGF silenced by siRNA or blocked by the antibody from the day of implantation showed a significant delay in tumor growth (p < 0.0001) and prolonged survival (p = 0.003) when compared to control IgG-treated mice. Treatment of established tumors with anti-PlGF antibody - started at ∼3 weeks post-implantation - showed stabilization of disease and regression of medulloblastomas (p = 0.017) by Gluc and whole body imaging measurements, and prolongation of survival (p = 0.0009). However, in vitro we found no direct effect of anti-PlGF treatment on tumor cells. Further mechanistic findings will be presented at the meeting.

Conclusion: PlGF is highly expressed in medulloblastomas. Mice bearing orthotopic tumors showed significantly delayed tumor growth and longer survival after PlGF inhibition. Thus, PlGF targeting in these tumors may provide a safe and efficient therapy for pediatric medulloblastoma.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr LB-363.
Abstract LB-368: III-tubulin knockdown in endothelial cells increases the antivascular activity of chemotherapeutic drugs
Authors: Pasquier Eddy , Sinnappan Snega , Verdier-Pinard Pascal , Braguer Diane , Kavallaris Maria
Published: February 2011

The microtubule cytoskeleton plays a crucial role in tumor angiogenesis, as evidenced by the potent anti-vascular properties of microtubule-targeting anticancer agents (MTAs). Accumulating evidence shows that the expression level of β-tubulin isotypes influences drug response and βIII-tubulin in particular has been involved in cancer cell resistance to MTAs as well as other classes of chemotherapeutic agents (1). However, the role of β-tubulin isotypes in the context of tumor angiogenesis and anti-vascular therapy remains unknown. Comparative western blot analysis revealed that human vascular endothelial cells express relatively high levels of βII- and βIII-tubulin. Using siRNA gene silencing, we effectively suppressed the expression levels of βII-and βIII-tubulin isotypes in vascular endothelial cells, by 90% and 80%, respectively. Functional analysis showed that βII-tubulin expression did not significantly influence either the capacity of endothelial cells to form vascular structures on Matrigel or the anti-vascular properties of MTAs. In contrast, knocking down the expression of βIII-tubulin in endothelial cells significantly inhibited the formation of capillary-like structures on Matrigel by 18 ± 3 % (p<0.001). Furthermore, the anti-angiogenic activity of the microtubule-stabilizing agent, paclitaxel, and the microtubule-depolymerizing agents, vinblastine and 2-methoxyestradiol (2-ME2), was significantly increased between 1.6 and 2.5-fold (p<0.05) in βIII-tubulin knockdown endothelial cells, as compared to control siRNA and βII-tubulin knockdown cells. Similarly, the vascular-disrupting activity of ENMD-1198, a new analog of 2-ME2, was also increased by 2.2-fold (p<0.05) in βIII-tubulin knockdown endothelial cells. More broadly, βIII-tubulin knockdown in endothelial cells also increased the anti-angiogenic activity of other classes of chemotherapeutic drugs, such as topoisomerase inhibitor etoposide (18 ± 1%, p<0.01) and alkylating agent cyclophosphamide (35 ± 5%, p<0.05). Altogether these results strongly suggest that βIII-tubulin may play a role in tumor angiogenesis and influence the anti-vascular activity of chemotherapeutic drugs. Further investigations are currently underway to unravel the underlying mechanisms.

References

1. Gan P., Pasquier E. and Kavallaris M. Class III beta-tubulin mediates sensitivity to chemotherapeutic drugs in non-small cell lung cancer. Cancer Res. 2007, 67: 9356-9363.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr LB-368.
Abstract LB-377: Regulation of expression of choline kinase by a conserved HIF1 binding hypoxia-responsive element
Authors: Bansal Aditya , Harris Robert A. , DeGrado Timothy R.
Published: February 2011

Hypoxic microenvironment and overexpression of choline kinase alpha (ChKa) have been associated with tumor malignancy, but the regulation of ChKa expression in hypoxic conditions is poorly understood. In this study, the effects of chronic hypoxia on choline metabolism and ChKa expression were examined in prostate cancer cell line, PC-3. Chronic hypoxia (1% O2, 24h) decreased proliferation rate and intracellular levels of phosphocholine, while intracellular levels of free choline were increased. Choline tracer uptake and washout studies confirmed the decreased rate of choline phosphorylation in hypoxic cells. Overexpression of HIF1a or DMOG exposure in normoxic PC-3 cells decreased both choline uptake and choline kinase activity. RT-PCR analysis showed decreased transcription of ChKa gene in hypoxic PC-3 correlating with decreased enzymatic activity of choline kinase in hypoxic cell extracts. Alignment of nucleotide sequence of the putative promoter region of ChKa from rat, mouse, chimpanzee and human revealed a highly conserved hypoxia responsive element upstream to transcription start site of ChKa. Electrophoretic mobility shift competition/supershift assay and chromatin immunoprecipitation-quantitative PCR assay confirmed binding of native HIF-1α protein to the conserved HRE. To understand the transcription control of ChKa under hypoxia, a putative promoter of ChKa was isolated from PC-3 genomic DNA and cloned into a luciferase (Luc) based reporter vector system. In PC-3, hypoxia decreased the expression of Luc under the control of the ChKa promoter. Mutation of the conserved HRE and subsequent Luc reporter assays demonstrated that this HRE is involved in hypoxia/HIF1α mediated regulation of ChKa. The results suggest that the decreased choline phosphorylation in PC-3 cells in response to hypoxia is mediated in part by the newly-identified conserved HIF1α binding HRE.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr LB-377.
Abstract LB-386: The role of neuronal connexins in the differentiation of neuroblastoma
Authors: Sidhu Mandeep , Belliveau Daniel
Published: February 2011

Gap junctions are membrane channels allowing intercellular communication between adjacent cells, and regulate cellular processes such as metabolism, proliferation, and differentiation. Connexins (Cx), the constituent proteins of gap junctions, are aberrantly localized or have decreased expression in many cancers, and some connexins act as tumor suppressors when overexpressed. Connexins are also highly regulated during development and when overexpressed, some have been shown to enhance cellular differentiation. In the present study, the role of neuronal connexins, Cx36 and Cx45, in the differentiation of SH-SY5Y human neuroblastoma cells was investigated. Retinoic acid was used as the differentiating agent, as it is often employed in differentiation therapy of tumor cells. Retinoic acid induces neuritogenesis and expression of differentiation markers, such as growth associated protein 43 (Gap43), neuropeptide Y (NPY), and neuron specific enolase (NSE) in SH-SY5Y cells. Following 2, 4, and 10 days of retinoic acid induced differentiation of SH-SY5Y cells, Cx36 mRNA expression showed a significant increase compared to non-treated cells, while Cx45 mRNA expression remained stable. Cx36 was overexpressed using liposome-mediated transfection, and an increase in the mRNA levels of Gap43, NSE, and NPY was observed after 48 hours compared to control EGFP transfected cells. Cx36 overexpression also enhanced retinoic acid induced differentiation, as evidenced by the increase in mRNA expression of differentiation markers, Gap43 and NPY, following 2 days of treatment, and will now be confirmed following 4 and 10 days of treatment. Therefore, Cx36 overexpression induces and enhances the differentiation of SH-SY5Y neuroblastoma cells. Current studies involve knocking down Cx36 and Cx45 with shRNA and inducing differentiation of SH-SY5Y cells to determine whether connexin knock down diminishes neuritogenesis or differentiation marker expression. These studies provide insight into the role of connexins in the differentiation therapy approach to cancer treatment.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr LB-386.
Abstract LB-387: MYCN dependence of tumor propagating cells in an orthotopic model of medulloblastoma
Authors: Ahmad Zai , Moore Amy , Barker Karen , Vaughan Lynsey , Popov Sergey , Pearson Andrew DJ , Chesler Louis
Published: February 2011

Medulloblastoma (MB) is the most common paediatric brain tumor and is a major cause of cancer death in children. MYCN expression is critical to cerebellar development, regulates the fate of neural progenitor cells (NPCs) and drives the expansion of tumor propagating cells (TPCs) thought to represent the cell-of-origin for this disease.

To examine the role of MYCN in MB tumorigenesis, we established neurosphere cell lines enriched for putative TPCs from the cerebella of GTML mice (transgenic for doxycycline-regulable overexpression of MYCN and luciferase). These mice are predisposed to anaplastic/large-cell MB (AACR abstract LB-79).

Neurospheres derived from GTML cerebella with positive luciferase imaging signals but no visible tumor tissue exhibited several characteristics consistent with enrichment for TPCs and/or NPCs. Spheroids proliferated efficiently in the absence of exogenous growth factor, exhibited self-renewal in clonal dilution assays, expressed high levels of Mycn protein and the NPC markers nestin and SOX2, and in response to serum, differentiated along neuronal and glial lineages (increased GFAP and III tubulin expression by immunofluorescence). Finally, orthotopic reimplantation at low titer (<250 cells) recapitulated anaplastic/large-cell MB tumor formation with short latency (<14 days) and complete penetrance.

Suppression of MYCN with doxycycline (confirmed by loss of luciferase imaging) caused growth arrest via a G1 blockade of neurospheres in vitro. Pretreatment of implanted spheres significantly reduced tumor penetrance (<60%) and increased latency (2-3 months). Efficient regression of established tumors was observed with concomitant loss of nestin expression and increases in differentiated glial and neuronal markers.

Taken together, these data suggest that MYCN expression drives MB tumor formation by maintenance or expansion of a population of relatively undifferentiatedTPCs present in normal cerebella. This model represents a significant tool for further investigation of the role of MYCN in MB initiation and progression.

Note: This abstract was not presented at the AACR 101st Annual Meeting 2010 because the presenter was unable to attend.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr LB-387.
Abstract LB-39: Development of a novel water-soluble prodrug of paclitaxel that is cleaved by prostate-specific antigen (PSA): In vitro and in vivo evaluation
Authors: Elsadek Bakheet , Graeser Ralph , Esser Norbert , Ajaj Khalid Abu , Saleem Tahia , Melegy Nagla El , Madkor Hafez , Kratz Felix
Published: February 2011

In developed countries, prostate cancer is the second most frequently diagnosed cancer, and the third most common cause of death from cancer in men. Unfortunately, while accumulating clinical data have suggested that the taxanes may prolong the survival in a subset of men with prostate carcinoma, the dose and duration of administration of these drugs are limited by their significant systemic toxicities due to a lack of tumor selectivity. Besides prostate cancer, paclitaxel (Taxol®) is currently showing a promising antitumor activity against a variety of human tumors. In an attempt to improve both the water solubility and tumor targeting properties of paclitaxel, we set out to develop a water soluble paclitaxel prodrug that is activated specifically by prostate-specific antigen (PSA) which is solely expressed in prostate tissue and prostate carcinoma with high levels up to mg/g present in human prostate carcinoma. Using albumin as an efficient carrier for drug delivery, we describe a novel albumin-binding prodrug of paclitaxel, EMC-Arg-Ser-Ser-Tyr-Tyr-Ser-Leu-PABC-Paclitaxel [EMC: -maleimidocaproyl; PABC: p-aminobenzyloxycarbonyl] that was synthesized by reacting EMC-Arg-Ser-Ser-Tyr-Tyr-Ser-OH with H-Leu-PABC-Paclitaxel. This prodrug exhibited excellent water-solubility and was bound rapidly to the cysteine-34 position of endogenous and exogenous albumin. Moreover, incubation studies with PSA demonstrated that the albumin-bound form of the prodrug was cleaved rapidly at the P1-P‘1 scissile bond releasing the paclitaxel-dipeptide H-Ser-Leu-PABC-Paclitaxel. Above all, due to the incorporation of a PABC self-eliminating linker, this dipeptide was rapidly degraded to liberate paclitaxel as a final cleavage product within a few hours in prostate tumor tissue homogenates. Of note was that the albumin-bound form of the prodrug was approximately 4-fold more active in killing PSA-positive LNCaP cells than paclitaxel. In addition, orientating toxicity studies in mice showed that the maximum tolerated dose of the novel paclitaxel prodrug was twice that of conventional paclitaxel. Therefore, the in vivo efficacy of the prodrug (24 mg/kg paclitaxel equivalents) in comparison to free paclitaxel (12 mg/kg) is currently being evaluated in a mouse model of human prostate cancer using luciferase transduced LNCaP LN cells orthotopically implanted in SCID mice.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr LB-39.
Abstract LB-390: Thyroid cancer incidence trends by gender and histology in Sao Paulo, Brazil, 1997-2005
Authors: Veiga Lene , Neta Gila , Ron Elaine
Published: February 2011

Thyroid cancer incidence has been increasing steadily in much of the developed world, but there is limited information on trends in the developing world. The overall rise in thyroid cancer incidence varies by gender, race/ethnicity, and geographic location, with the largest increases found among women and white non-Hispanics. Where histology is available, this increase has been accompanied by a change in the distribution of histological types, with a particular increase in papillary thyroid cancer. Sao Paulo, Brazil is the largest registry in Brazil and covers has one of the ten highest rates of thyroid cancer incidence worldwide, and has the highest rate among Brazilian registries. The Sao Paulo Registry covers about 15 million people in the region. Approximately 1000 new thyroid cancer cases are documented each year in Sao Paulo. This large number of cases presents the opportunity to evaluate trends in thyroid cancer incidence in a Latin American population. Using 12,495 cases reported between 1997 and 2005 to the Sao Paulo Cancer Registry, we analyzed thyroid cancer incidence patterns by gender and histology using Joinpoint analysis to calculate the annual percentage change (APC) in incidence, adjusting for age (standard world population). We found that females made up the vast majority of cases (87%) compared with males (13%). Papillary was the most common histology (74.7%), followed by follicular (17.3%), medullary (4%), and other (4%) among 77% of cases with histological confirmation. Overall incidence rates increased for both males and females, with a larger APC for females (+7.7%) compared with males (+6.6%). The greatest increases were seen for papillary and follicular histologies for both sexes. Rates increased most for females and males greater than 50 years of age compared with those 50 years or younger. Mortality rates remained relatively constant. These findings suggest that incidence rates of thyroid cancer are increasing in Sao Paulo, following a similar trend as seen in many developed countries. Further research looking at tumor stage and size could help to understand the potential causes of this increase.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr LB-390.
Abstract LB-392: Ethnic/racial differences in bladder cancer risk: the Multiethnic Cohort
Authors: Setiawan Veronica W. , Henderson Brian E. , Wilkens Lynne R. , Kolonel Laurence N. , Marchand Loic Le
Published: February 2011

Few studies have examined differences in bladder cancer risk among ethnic groups in the United States. We investigated racial/ethnic differences in bladder cancer risk and cancer stage and risk factors for bladder cancer among 189,998 African-American, Japanese-American, Latino, Native Hawaiian, and White men and women in the Multiethnic Cohort Study. We included 880 incident cases of bladder cancer (685 males and 195 females) identified in the cohort over an 11-year period, between baseline (1993 through 1996) and 2004. Data on known/potential risk factors for bladder cancer were obtained from the baseline questionnaire. Among many potential risk factors examined, only cigarette smoking-related variables (e.g. cigarette dose, years of smoking, pack-years, and years since quitting) were significantly associated with risk of bladder cancer in both men and women; the associations were observed in all five racial/ethnic groups. Racial/ethnic differences in bladder cancer risk were observed in men (P<0.0001) and women (P=0.001). Whites, by far, had the highest risk of bladder cancer compared to other racial/ethnic groups; the relative risks (RRs) (vs. Whites) were 0.65 [95% confidence intervals (CI): 0.53, 0.80] for African Americans, 0.63 (95%CI: 0.46, 0.86) for Native Hawaiians, 0.59 (95%CI: 0.49, 0.69) for Japanese, and 0.41 (95%CI: 0.33, 0.50) for Latinos. After adjustment for cigarette dose, the RRs were 0.69 (95%CI: 0.56, 0.85) for African Americans, 0.65 (95%CI: 0.47, 0.89) for Native Hawaiians, 0.62 (95%CI: 0.52, 0.73) for Japanese, and 0.48 (95%CI: 0.38, 0.59) for Latinos. Similar results were obtained when other smoking variables were considered for adjustment. Although Whites had the highest risk of developing bladder cancer, African-American (P=0.007) and Latino (P=0.008) women were more likely to be diagnosed with advanced disease. Among current and former cigarette smokers, regardless of their smoking dose, Whites were more susceptible to bladder cancer than African Americans, Hawaiians, Japanese, and Latinos. Results from this study suggest that differences in self-reported smoking characteristics among men and women of different races/ethnicities do not fully explain interethnic differences in bladder cancer risk.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr LB-392.
Abstract LB-399: Use of metformin and the risk of cancer in the EPIC-Italy centers
Authors: van Veldhoven Karin , Sacerdote Carlotta , Ricceri Fulvio , Russo Alessia , Krogh Vittorio , Panico Salvatore , Palli Domenico , Tumino Rosario , Berrino Franco , Matullo Giuseppe , Vineis Paolo
Published: February 2011

Background: Recent epidemiological studies suggest a reduced cancer incidence and mortality among metformin users. Some studies also assessed treatment with other anti-diabetic drugs, such as insulin, and found an increased risk of cancer.

Our aim is to investigate in a large prospective study the possible association between metformin use and other anti-diabetic drugs and the risk of cancer. In order to disentangle the protective effect of metformin from the possible increased risk of other anti-diabetic drugs we will compare diabetic patients treated with metformin to diabetic patients treated with other anti-diabetic drugs and to non-diabetic subjects.

Methods: We have requested data on diabetic patients and non-diabetic subjects from 5 different centers in Italy (about 40000 volunteers enrolled), participating in the European Prospective Investigation into Cancer and Nutrition (EPIC) study. We expect to have approximately 1500 incident and 1000 prevalent diabetic patients. We will adjust our analyses for anthropometric, dietary, and lifestyle factors.

Preliminary analyses have been performed on the Turin cohort, including 473 incident and 214 prevalent diabetic patients. We calculated odds ratios (ORs), adjusting for age and sex for diabetic patients developing cancer using metformin compared to diabetic patients not using metformin.

Results: Among both incident and prevalent diabetic patients we found a decreased risk of cancer for metformin users versus non-metformin users: OR=0.89, 95%CI=0.25-3.14 and OR=0.61, 95%CI=0.22-1.69 respectively, however, these results were not statistically significant.

Conclusion: The results seem to suggest a protective effect of metformin, although it is not statistically significant. Using data from all EPIC-Italy centers will increase our power. This will be the largest prospective cohort study investigating the possible association between the use of metformin and other anti-diabetic drugs, and cancer incidence, comparing diabetics to non diabetics and adjusting for different possible confounding factors.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr LB-399.
Abstract LB-40: Inhibition of anchorage-independent growth of melanoma cell lines using Riluzole in combination with PI3 kinase pathway inhibitors
Authors: Goydos James S. , Salehomoum Negar M. , Rosenberg Steve , Chan Joseph L-K , Wen Yu
Published: February 2011

We previously reported that the majority of human melanomas express metabotrophic glutamate receptor 1 (GRM1), a cell surface glutamate receptor. We recently completed a Phase 0 trial of Riluzole, a glutamate release inhibitor, in patients with advanced melanoma and showed a clinical response of 34%. We have also shown that Riluzole, can effectively block invasion and migration of melanoma cells in vitro. In our in vitro studies it was observed that the efficacy of Riluzole treatment on anchorage independent growth was attenuated in melanoma lines harboring activated BRAF/NRAS mutations or a PTEN deletion. We have continued our pre-clinical studies by further examining the effects of Riluzole in combination with inhibitors of specific signaling molecules of the PI3 kinase pathway. Specifically, we tested the AKT inhibitor API-2 and the mTOR inhibitor Rapamycin. These inhibitors were used alone or with Riluzole on C8161 (grm1+, braf/nraswt, ptenwt), HT144(GRM1+, BRAFV600E, PTENdel) SKMEL-2(grm1+, nrasq61r) and UACC930(grm1-,brafv600e, ptendel) melanoma cell lines. When treating the GRM1+ cell lines with the individual agents, there was a moderate reduction in the number of colonies relative to the control. However, the combination of Riluzole with API-2 or Rapamycin had a more robust reduction in colony formation. This inhibition was not observed in the GRM1- UACC930 melanoma line where Riluzole in combination with either API-2 or Rapamycin did not induce a significant decrease in colony formation over single treatment with either agent. In addition to the effect on the number of colonies, the combinational treatments had a significant inhibitory effect on the size of the colonies relative to single agent treatments. The monolayer growth assays also demonstrated increased inhibition of growth with the combinational treatments versus single agent treatments. We conclude that the combination of glutamate signaling blockade combined with inhibition of PI3K signaling with either Rapamycin or API-2 is more effective at inhibiting GRM1 expressing melanoma cell proliferation than treatment with any of the agents alone. Combination therapy with Riluzole and either Rapamycin or API-2 may prove a more effective therapy than Riluzole alone in patients with melanoma.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr LB-40.
Abstract LB-430: Chemopreventive effect of beta-cryptoxanthin on smoke-induced lung inflammation and lesions in ferrets
Authors: Liu Chun , Bronson Roderick T. , Wang Xiang-Dong
Published: February 2011

Background: High intake of beta-cryptoxanthin has been associated with a decreased risk of lung cancer, particularly among current smokers in epidemiological studies. However, there are no available data from well-controlled animal studies to examine the effect of beta-cryptoxanthin on smoke-induced lung lesions and potential biological mechanisms by which beta-cryptoxanthin affects lung carcinogenesis. Using a ferret animal model, we evaluated the effect of beta-cryptoxanthin supplementation in both low-and high-dose (7.5 mcg/kg body weight per day vs. 37.5 mcg/kg body weight per day in ferrets which are equivalent to 104 mcg/day vs. 520 mcg/day, respectively, in the humans) on the cigarette smoke-induced pro-inflammatory cytokine TNF alpha, inflammation and squamous metaplasia in the lung.

Methods: Thirty six male ferrets were assigned to one of six groups (n = 6 in each group) for 9 weeks as follows: 1) control; 2) cigarette smoke exposed; 3) low-dose beta-cryptoxanthin (7.5 mcg/kg body weight per day); 4) high-dose beta-cryptoxanthin (37.5 mcg/kg body weight per day); 5) cigarette smoke-exposed plus low-dose beta-cryptoxanthin; and 6) cigarette smoke-exposed plus high-dose beta-cryptoxanthin. Lung TNF alpha was measured by immunohistochemical staining. Lung inflammation and squamous metaplasia were quantified by histopathological evaluations.

Results: Beta-cryptoxanthin supplementation dose-dependently increased plasma and lung beta-cryptoxanthin levels in ferrets. Cigarette smoke exposure lowered plasma and lung beta-cryptoxanthin levels. Treatment with beta-cryptoxanthin substantially reduced the cigarette smoke-elevated TNF alpha levels in bronchial/bronchiolar epithelial cells, alveolar epithelial cells, airway serous/mucous glands and lung macrophages. Beta-cryptoxanthin at both doses also significantly decreased the cigarette smoke-induced lung inflammation. In addition, both doses of beta-cryptoxanthin significantly lowered the incidence of lung squamous metaplasia induced by cigarette smoke exposure. There were no detectable squamous metaplasia in the groups treated with beta-cryptoxanthin alone and in the control group.

Conclusions: Beta-cryptoxanthin may provide a beneficial effect against the smoke-induced lung inflammation and lung lesions.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr LB-430.
Abstract LB-434: Colorectal, prostate, and skin cancer screening among Hispanic and white non-Hispanic men, 2000-2005
Authors: Jing Zhou , Enewold Lindsey , Peoples George E. , McLeod David G. , Potter John F. , Steele Scott R. , Clive Kevin S. , Stojadinovic Alexander , Zhu Kangmin
Published: February 2011

One of the most effective means of reducing cancer-specific mortality is early detection via cancer screening; however, Hispanic men continue to have lower colorectal, prostate and skin cancer screening rates than White non-Hispanic men. To combat this disparity and educate men and women aged 50 and older about the importance of regular colorectal cancer (CRC) screening, the Screen for Life campaign, which included directed intervention materials in Spanish as well as in English, was launched by the Center for Disease Control and Prevention (CDC) in 1999. We hypothesized that CRC screening rates would increase overtime among Hispanics and non-Hispanics as a result of this campaign and that prostate and skin cancer screening would also increase due to screening recommendations and raised awareness and necessity of cancer screening. The objective of this study was to assess whether CRC, as well as prostate and skin cancer screening rates among Hispanic and White non-Hispanic men changed between 2000 and 2005 using the National Health Interview Survey (NHIS) data. Our results showed that Hispanic men were less likely to comply with cancer screening guidelines for these three common malignancies than White non-Hispanic men. However, significant increases in CRC endoscopic screening were observed in both ethnic groups. It increased 2.1-fold and 2.4-fold for Hispanic and White non-Hispanic men, respectively (P<0.05). In contrast, the use of home fecal occult blood tests remained stable among Hispanics and decreased significantly among White non-Hispanics. PSA screening remained stable, while the use of skin cancer screening tended to increase among both ethnic groups. Our study suggests that a targeted public education program that is culturally sensitive and linguistically appropriate may be effective in increasing CRC screening rates.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr LB-434.
Abstract LB-435: Treatment decision-making for clinically localized Gleason score 6 prostate cancer: What younger men choose and why
Authors: Sidana Abhinav , Trock Bruce , Feng Zhaoyong , Hernandez David , Epstein Jonathan
Published: February 2011

Introduction: This study identifies various treatment related information sources used by young men with prostate cancer (<50 years) and evaluates the association between decision making preferences and sociodemographic factors.

Methods: A survey was sent to 986 men under 50 years of age diagnosed with Gleason 6 prostate cancer from the consult service of one of the authors at Johns Hopkins Department of Pathology between 2001 and 2005.

Results: 488 completed questionnaires were received. Physicians and internet were two most common information sources used by the patients. Physicians were a more important information source for white men (p=0.04) and those with higher education (p=0.036). Family was an important information source in married men (p<0.001) and those with higher education (p<0.001). Three most important influential factors for treatment decision were doctor's recommendation, information from internet and spouse's advice. Most patients (88%) consulted more than 2 doctors while making a decision. Men with higher education (p=0.003) and higher income (p=0.003) tend to consult more doctors. Most respondents said that their doctor endorsed only one treatment, primarily surgery. 76% of the respondents said that their doctors recommended against watchful waiting. Men who underwent surgery considered doctor's recommendation as the most influential factor while those who had radiation considered information from internet, books and medical journals as most influential (p=0.018). Treatment choice was not influenced by PSA value at diagnosis. Subjects with higher education and higher income considered sexual function as a more influential factor while making a treatment choice. Better educated men preferred” informed decision making” over “complete reliance on doctor” (p=0.013). Non-married men found the decision more difficult to make (p=0.032), were more worried (p=0.0005) and experienced more distress (p=0.011) while making treatment decisions. Feeling of regret after treatment was experienced more by respondents with lower education (p=0.007) and lower income (p<0.0001).

Conclusions: Patients younger than 50 years diagnosed with localized prostate cancer sought information from a wide range of sources but are influenced most by the doctor's recommendation.

Note: This abstract was not presented at the AACR 101st Annual Meeting 2010 because the presenter was unable to attend.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr LB-435.
Abstract LB-49: ABC transporters in the blood-brain barrier limit the brain penetration of the PARP inhibitor ABT-888
Authors: Fan Lin , de Gooijer Mark C. , Beumer Jan H. , Christner Susan M. , Beijnen Jos H. , van Tellingen Olaf
Published: February 2011

Introduction: ABT-888 is a potent poly(ADP-ribose) polymerase (PARP) inhibitor and is currently in phase 2 clinical trials. PARP inhibitors enhance the activity of DNA damaging therapies, due to the critical function of PARP-1 and PARP-2 in base excision repair. The combination of ABT-888 with chemo-radiation therapies for the treatment of glioma patients is receiving considerable interest because this combination has shown promise in preclinical models.

High-grade glioma patients have a very poor prognosis, in particular due to the inability to achieve complete surgical resection. Importantly, the residual tumor cells that have infiltrated surrounding normal brain tissue are using pre-existing brain vasculature and are thus protected by the blood-brain barrier (BBB). Consequently, the ability of potential chemotherapeutics to cross the BBB, including the role of ABC transporters in brain penetration, needs to be characterized.

Goal: To establish the impact of the BBB and the role of the ABC transporters ABCB1 and ABCG2 in the brain disposition of ABT-888. Methods: We performed in vitro transwell assays using polarized epithelial monolayers of parental vs ABC-transporter transduced cell lines. In vivo pharmacokinetic studies were conducted with wildtype (WT), single and compound ABC transporter knockout mice. Drug concentrations were determined by HPLC-UV and LC-MS.

Results: Transwell assays demonstrated basolateral-to-apical translocation in both Abcb1 expressing LLC-Mdr1a vs LLC-PK1 cells as in Abcg2 expressing MDCK-Bcrp1 vs MDCK-parent cells, which could be inhibited by zosuquidar and elacridar, respectively.

The plasma levels of ABT-888 in WT vs single Abcb1−/−, single Abcg2−/−, or compound Abcb1−/−;Abcg2−/− mice 1 h after i.v. administration of 10 mg/kg were not different. However, the brain-to-plasma ratios for WT, Abcb1−/−, Abcg2−/−, and Abcb1−/−;Abcg2−/−mice were 0.98, 4.46 ((p<0.006*), 1.45 (p=NS*) and 7.47 (p<0.001*, p=0.022**), respectively. Significance was assessed by ANOVA with Bonferroni post-hoc test (*relative to WT; **relative to Abcb1−/−).

Conclusions and Relevance: The brain penetration of ABT-888 is more than 7-fold reduced by the action of Abcb1 and Abcg2, with Abcb1 being the most important limiting factor. This information will aid in the interpretation of clinical trials in glioma. Disappointing efficacy of ABT-888 based therapy in glioma may merely reflect inadequate drug exposure, and could be improved by using inhibitors of selected ABC-transporters or by the development of PARP inhibitors with lesser affinities for ABC-transporters.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr LB-49.
Abstract LB-5: RUNX3 targets estrogen receptor α for proteasome-mediated degradation suppressing breast cancer tumorigenesis
Authors: Huang Bo , Qu Zhaoxia , Victor Adrienne , Zhang Chen , Yang Xiao-dong , Ito Kosei , Xiao Gutian , Ito Yoshiaki , Shapiro David , Chen Lin-Feng
Published: February 2011

Transcription factor RUNX3 is inactivated in a number of malignancies including breast cancer and is suggested to function as a tumor suppressor. However, the exact mechanism for its tumor suppressor function in breast cancer remains elusive. Here we demonstrate that RUNX3 interacts with estrogen receptor α (ERα) and reduces ERα-mediated transactivation by stimulating the ubiquitination and proteasome-mediated degradation of ER. Consistent with its ability to reduce levels of ERα, expression of RUNX3 inhibits the estrogen-dependent proliferation and transformation potential of ER -positive MCF-7 breast cancer cells in liquid culture and in soft agar and suppresses the tumorigenicity of MCF-7 cells in mice. Thus, these studies reveal modulation of ERα stability as a novel mechanism by which RUNX3 functions as a tumor suppressor in ERα-positive breast cancer.

Note: This abstract was not presented at the AACR 101st Annual Meeting 2010 because the presenter was unable to attend.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr LB-5.
Abstract LB-50: Overexpression of PBX1 is associated with recurrence and worse clinical outcome in patients with recurrent ovarian high-grade serous carcinoma
Authors: Kuhn Elisabetta , Park Joon T. , Davidson Ben , Kurman Robert J. , Shih Ie-Ming , Wang Tian-Li
Published: February 2011

PBX1 has been initially identified as a proto-oncogene in human leukemia in a form of the E2A-PBX1 fusion protein. PBX1 is currently known as a regulator of self renewal of stem cells which contributes to maintenance of a “stemness” phenotype mainly through TGF-ß signaling. PBX1 was recently shown to be elevated in ovarian cancer and its locus was found to be frequently amplified in many cancer types including ovarian carcinoma.

In order to further understand the clinicopathological and prognostic significance of PBX1 in ovarian carcinoma, we investigated the gene expression of PBX1 in patients with ovarian high-grade serous carcinoma (HGSC). PBX1 mRNA levels were analyzed in a panel of 78 ascites from patients with HGSC (including 36 primaries and 42 recurrences) by quantitative RT-PCR. Moreover, we performed immunohistochemical staining for PBX1 in 25 pairs of matched primary and recurrent HGSCs from the same patients. The results were correlated with clinicopathological data.

Kaplan-Meier analysis demonstrated higher PBX1 levels in ascites from patients with recurrent/chemoresistant HGSC and an association with worse overall survival (p=0.026) as well as disease-free survival (p=0.024). Patients’ effusions with high PBX1 levels (based on median cut-off, n=22) had a mean overall survival of 26 months vs. 39 months for patients whose effusions showed low PBX1 expression (n=20). Patients’ effusions with high PBX1 expression (n=21) also had a mean progression-free survival of 4 months vs. 10 months for patients whose effusions showed low PBX1 levels (n=20). Furthermore, we found more intense PBX1 immunoreactivity in recurrent HGSCs than in matched primaries (Paired t test, p=0.024). Finally, PBX1 expression in primary HGSCs did not demonstrate any significant correlation with patients’ clinical outcome.

This study is the first one demonstrating that PBX1 expression correlates with recurrent disease and is associated with worse clinical outcome in patients who develop recurrent HGSC. Future studies will aim at determining the usefulness of PBX1 immunoreactivity as a biomarker to predict patient treatment response and whether it can be a potential molecule for drug-targeted treatment in patients with recurrent HGSC.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr LB-50.
Abstract LB-55: Histone deacetylase inhibitor causes DNA damage and apoptosis by downregulation of repair enzymes in cancer but not normal cells: Basis of resistance of normal cells to HDACi
Authors: Lee Juhee , Choy Megan L. , Ngo Lang , Foster Steven , Xu Weisheng , Petrini John H. , Marks Paul A.
Published: February 2011

Histone deacetylase inhibitors (HDACi) developed as anti-cancer agents have a high degree of selectivity for killing cancer cells. HDACi induce acetylation of histones and many non-histone proteins, affecting gene expression, cell cycle progression, cell migration and cell death. The mechanism of the tumor selective action of HDACi is unclear. Here we show that the HDACi, SAHA (Suberoylanilide hydroxamic acid, vorinostat), induces DNA DSB (double strand break) in normal (HFS) and cancer (LNCaP, A549) cells, but normal cells in contrast to cancer cells repair the DSB despite continued culture with SAHA.

In transformed cells, H2AX levels increased with continued culture with SAHA, while in normal cells, this marker of DNA DSB tended to decrease with time. To define the capacity of normal and transformed cells for repair of SAHA induced DNA DSB, cells were cultured for 24hr with SAHA, washed and continued culture without HDACi. In normal cells, the H2AX was undetectable by 2hr (presumably reflecting repair of DNA DSB), while persisting in transformed for duration of culture (presumably reflecting failure to repair DNA DSB) with consequent transformed cell death. Further, we found that SAHA suppressed DNA DSB repair proteins, e.g., RAD50, MRE11, Tip60 and PP2A, in cancer (LNCaP, A549) but not in normal cells (HFS).

These findings indicate that the HDACi induces DNA damage in cancer and normal cells, but normal cells have the capacity to repair the DNA DSB, while cancer cells do not owing in part at least to suppression of DNA DSB repair proteins. This selective action of SAHA in inducing transformed cell death points to potential effective therapeutic strategies for combination therapy with HDACi with agents that suppress DNA damage repair proteins.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr LB-55.
Abstract LB-61: Comparative study of different diagnostic techniques (AI, MLPA, FISH) in breast cancer patients with 1q25.3 alterations
Authors: Wiechec Emilia , Kjeldsen Tina , Overgaard Jens , Kjeldsen Eigil , Hansen Lise Lotte
Published: February 2011

Background: Breast cancer is the most frequently diagnosed malignancy among women and is the leading cause of cancer related death worldwide. Molecular genetic studies have revealed many subgroups of breast cancer within which the genomic alterations affecting chromosome arm 1q are considered to be an early event in breast carcinogenesis and are correlated with favorable prognosis for the patients.

We have found a high percentage of concordance between the AI and MLPA assays pointing towards gain of the 1q25.3 region in breast cancer.

Aims: Our main objective was to compare the sensitivity and specificity of AI and synthetic probe-based MLPA with other cytogenetic method (FISH) in breast cancer patients with or without previously confirmed alterations within 1q25.3.

Methods: FISH was performed on formalin-fixed paraffin-embedded tumor material in order to verify previous findings and assess the level of genetic alterations of 1q25.3 in breast cancer. The 1q25.3 test and 1p35 reference probes labeled with different fluorochromes were utilized for analysis.

Results: A total of 70 nuclei from each breast cancer case were examined and scored for the percentage of 1q25.3 alterations. The non-tumorigenic nuclei obtained from healthy individuals served as adequate cut-off for the 1q25.3-specific changes. The overall FISH results are consistent with results obtained from previous analysis in the majority of analysed cases. Furthermore, FISH resolved the level of 1q25.3 alterations in few cases that were uncertain by AI and MLPA analysis.

Conclusion: This study shows that both AI and MLPA assays are able to map regions of copy number changes in the cancer genome and are in concordance with molecular cytogenetics. These three techniques proved to be an efficient tool for diagnosis of 1q25.3 alterations, however, confusing results in AI and MLPA analysis might be obtained while using non-microdissected tumor DNA as a template.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr LB-61.