bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 3443: Targeting G2/M cell cycle regulators in medulloblastoma tumor-propagating cells
Authors: Markant Shirley L. , Barton Kelly , Sun Jesse , Wechsler-Reya Robert
Published: June 2012

Medulloblastoma is the most common malignant brain tumor in children. While the current treatment strategy of surgery, radiation and chemotherapy has a 60-80% cure rate, the survivors suffer severe side effects, including growth delays and cognitive deficits. Therefore, more effective, less toxic treatments are needed. One approach to achieving this is targeting the cells within a tumor that are capable of re-populating the tumor, known as tumor-propagating cells (TPCs). In the patched mutant mouse model of medulloblastoma, TPCs are marked by expression of the cell surface carbohydrate antigen CD15. Our previous studies suggest that CD15+ cells display increased expression of genes associated with G2/M phase of the cell cycle. Cell cycle analysis suggests that these CD15+ cells move quickly through the G1 and S phases of the cell cycle, but accumulate in G2/M phase. Therefore, inhibition of G2/M regulators, such as Aurora kinases, may represent one approach to targeting TPCs in these tumors. Treatment of tumor cells with the Aurora kinase inhibitor VX-680 (tozasertib) leads to inhibition of proliferation in vitro, with arrest in G2/M and apoptosis. Preliminary studies suggest that patched mutant tumors are also sensitive to Aurora kinase inhibition in vivo. Our findings suggest that targeting Aurora kinases may represent a novel approach for the treatment of hedgehog-associated human medulloblastoma.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 3443. doi:10.1158/1538-7445.AM2011-3443
Abstract 3456: RNA and microRNA analysis of diffused intrinsic pontine glioma specimens
Authors: Sandza Annie E. , Hill Ashley , MacDonald Tobey , Nazarian Javad
Published: June 2012

Diffused intrinsic pontine glioma (DIPG) is one of the most difficult pediatric cancers to treat. To date, there is only limited information on the molecular characteristics of this tumor because of the paucity of adequate tissue for investigation due to its inoperable location within the brainstem. In an attempt to uncover the pathogenesis of DIPG, we have generated comprehensive molecular profiles of coding and non-coding RNA species obtained from pediatric DIPG autopsy specimens. Coding and non-coding RNA species play an important role in oncogenesis. Micro RNAs (miRNAs or miRs) are the more recent non-coding RNA species that have been shown to play an essential role in cancer development and cancer biology. Our aim was to gain insight into the molecular underpinnings of DIPG by generating the complete miRNA and mRNA profiles of the tumor.

Autopsy DIPG specimens were analyzed (n=3). Adjacent non-tumor areas were identified by a neuropathologist and used as controls. Total RNA was extracted and coding and non-coding small RNA were profiled using the Affymetrix platform. A total of 60 miRNA species were found to be dysregulated in DIPG tumor compared to adjacent normal section. Of these, 12 were known human micro RNAs. RNA species that showed to be dysregulated were further validated by RT-PCR (ABI platform). Furthermore, correlation analyses were done to assess expression levels of mRNAs and their corresponding miRs. Our preliminary data indicates specific dysregulation of micro RNA and RNA species that control cellular proliferation and tumorigenesis.

Although preliminary, this is to our best knowledge, the first report of comprehensive RNA profiling of DIPG. Correlation of coding and non-coding RNA species observed here will require further validation. Understanding the molecular makeup of DIPG will provide insight into its pathogenesis and perhaps lead to the development of targeted therapeutics for this disease.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 3456. doi:10.1158/1538-7445.AM2011-3456
Abstract 3469: EphrinB2 promotes endothelial cell survival and vascular integrity
Authors: Salvucci Ombretta , Maric Dragan , Zhang Fan , Li Xuri , Basik Mark , Buchanan Marguerite , Tosato Giovanna
Published: June 2012

EphrinB transmembrane ligands and their cognate EphB receptors critically contribute to vascular development through cell-to-cell signaling by the EphB receptor (forward signaling) and by the EphrinB ligand (reverse signaling). Previous studies demonstrated that mutant mice lacking ephrinB2 or EphB4 and a proportion of mice lacking EphB2 and EphB3 display severe defects in the embryonic vascular system and die at the embryo stage likely due to these vascular defects. Previously, we showed that EphB2, EphB4 and EphrinB2 are required for mature endothelial cell assembly into capillary structures. In the currently studies, we observed that silencing EphrinB2 expression in different types of primary human endothelial cells causes significant and time-dependent apoptotic cell death, as measured by cleavage of Poly(ADP-ribose) Polymerase (PARP), caspase-3 and caspase-8. VEGF, bFGF and SDF-1 variously modulated apoptosis induced by loss of EphrinB2 expression in endothelial cells. Gene expression profiling revealed that EphrinB2 silencing is associated with reduced expression of genes linked to regulation of the cell cycle progression and cytoskeleton organization, and with increased expression of pro-apoptotic genes. Breast cancer tissue from a patient treated with bevacizumab, a humanized monoclonal antibody that neutralizes VEGF, displayed evidence of endothelial cell apoptosis, which was associated with selectively reduced EphrinB2 expression, suggesting a link between VEGF signaling, EphrinB2 expression and cell death. These studies show that EphrinB2 expression is critical to endothelial cell survival in vitro and suggest that EphrinB2 contributes to blood vessel integrity in vivo. Thus, in addition to its well-characterized function as a regulator of cell-to-cell adhesion and repulsion, EphrinB2 is an endothelial pro-survival molecule, which may serve as a novel target for anti-angiogenic therapies.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 3469. doi:10.1158/1538-7445.AM2011-3469
Abstract 3484: Murine and human lymphatic endothelial cells show similar marker profiles and migratory properties
Authors: Coso Sanja , Williams Elizabeth D.
Published: June 2012

Introduction: Lymphangiogenesis (growth of nascent lymphatic vessels in vivo and proliferation, migration and tube formation of lymphatic endothelial cells (LECs) in vitro) plays a key role in lymph node metastasis in a number of tumour types (1), including prostate cancer. Mechanisms underlying tumor cell-lymphatic vessel interactions are critical to understand. Thus determining the molecular basis of LEC motility and its relationship to lymphangiogenesis and subsequent metastasis will play an important part in developing novel strategies to prevent metastasis.

We have previously shown that members of the vascular endothelial growth factor (VEGF) family regulate migration of human LECs (2). As the effect of stimulation with VEGF family ligands has not been reported in murine LECs, this study aims to isolate and characterize murine LECs and to compare their migratory profiles to human LECs. This data will be important in determining the relevance of experiments utilizing LECs derived from transgenic and/or human tumor-bearing mice to the study of lymphangiogenesis in human cancers.

Results: Murine LECs were successfully isolated from prostate and skin using a CD34 depletion, CD31 positive selection strategy. Murine LECs expressed lymphatic endothelial cell markers Prox-1 and LYVE-1. The migratory profile of murine LECs was compared to human LECs using a panel of extracellular substrates and VEGF family ligands. VEGF-C and VEGF-D potently stimulated murine LEC migration in vitro. Stimulation of murine LECs with VEGF-C caused activation of pAKT(Ser347), Erk1/2 and JNK signalling pathways, consistent with observations in human LECs.

Conclusions: This study describes a successful, robust protocol for isolation of murine LECs. Murine LECs derived from transgenic and knock-out mouse models will provide important insights into the molecular mechanisms of lymphangiogenesis and allow the study of LECs in the context of cancer metastasis and other disease associated with altered lymphatic vessel architecture or function.

(1) Mumprecht V, Detmar M (2009) J Cell Mol Med, 13: 1405-16

(2) Zeng Y, Opeskin K, Goad J, Williams ED (2006) Cancer Res, 66: 9566-75

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 3484. doi:10.1158/1538-7445.AM2011-3484
Abstract 3489: In silico analysis of angiogenesis pathway as a prognostic tool in breast cancer
Authors: Mehta Rutika J. , Jain Rohit K. , Gökmen-Polar Yesim , Badve Sunil
Published: June 2012

Gene expression profiling studies have enabled us to study breast cancer biology at a molecular level. Studies have been geared at identifying better and comprehensive prognostic markers for the development of targeted therapeutics. With the growing use of anti-angiogenic agents as second line agents, we aim to study the prognostic role of angiogenesis related genes through retrospective analyses of publicly available breast cancer gene expression datasets.

Three gene expression datasets from studies by van't Veer et al, Sorlie et al., and Sotiriou et al were analyzed. The data was downloaded from the BRB Array Tools archives and analyzed using BRB Array Tools. Since, we were particularly interested in genes related to angiogenesis; we selected the (CGAP) angiogenesis subset for the purpose of survival analyses. Two endpoints, overall survival (OS) and relapse free survival (RFS), were analyzed. Data for OS was not available for van't Veer et al. A subset analysis for estrogen receptor positive cases was performed.

HIF1A was prognostic for OS and RFS in all datasets. VEGF was associated with survival only in ER+ cases. EGFR is prognostic for RFS but not OS. Several other angiogenesis genes were noted to affect prognosis in terms of OS and RFS (Table 1). Analysis of other publically available datasets will be undertaken to further validate these findings in ER+ and negative subgroups of breast cancer.

These analyses highlight the importance of VEGF as an important marker among ER+ breast cancer patients. Thus, anti-angiogenic agents targeting VEGF may appear to play an important therapeutic role in this subset of patients. The analysis provides additional evidence of the importance of HIF1A in breast cancer. This may help identifying sub-populations of breast cancer that are most likely to respond to targeted therapies. Further immunohistochemical validation in in-vitro models will be performed.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 3489. doi:10.1158/1538-7445.AM2011-3489
Abstract 3492: NET as a repressor on transcriptional regulation of MT1-MMP in endothelial cells
Authors: Heo Sun-Hee , Choi Young-Jin , Ryoo Hyun-Mo , Cho Je-Yoel
Published: June 2012

In mice deficient for the Ets family genes, disrupted angiogenesis and malformed vascular system inform critical role of Ets factors in vasculogenesis and angiogenesis. NET is a member of ETS transcription factors and acts as a repressor of transcription. To find role of NET in angiogenesis, angiogenesis related assay were carried out using NET specific siRNA. In addition, it was confirmed regulation of NET on transcription of angiogenesis-regulated genes. Our results showed that suppression of NET expression result in buildup of VEGF-induced tube formation. In addition, suppressed expression of NET induced expression of MT1-MMP. Induction of MT1-MMP expression by knock down of NET expression was not result direct effect of NET on transcription of MT1-MMP in endothelial cells. In endothelial cell, NET suppressed ETS-1 induced-transcriptional activity of MT1-MMP. Our results suggest that NET is a negative regulator of angiogenesis on indirect regulation of MT1-MMP and induction of tube formation by its expressional suppression.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 3492. doi:10.1158/1538-7445.AM2011-3492
Abstract 3506: γ-secretase inhibitor enhances anti-cancer effects of 5-FU in gastric cancer
Authors: Shin Ji-Young , Lee Kang-Duck , Shin Young-Ho , Chun Kyung-Hee
Published: June 2012

Surgery is the most effective therapy for early gastric cancers. In advanced gastric cancer (AGC), achievement of loco-regional control after tumor resection is less successful because of frequent recurrences after surgical and medical therapies. Combinations of 5-fluorouracil (5-FU) and platinum analogues or cytotoxic agents, such as capecitabine, cisplastin, oxaliplatin and S-1, are currently widely accepted as standard treatment for AGC. However, survival of AGC patients following sedative chemotherapy is poor. Therefore, the development of novel therapies has been needed, and some clinical studies already have been performed using novel molecular targeting agents have shown hopeful activity, particularly in combination with cytotoxic agents. Recently, the importance of Notch signal pathway has been reported in gastric cancer. Gamma-secretase inhibitors (GSI), a notch proteolytic activation blocker, can be considered as a novel target agent for gastric cancer.

In this study, the anti-proliferation effects of GSI combined with 5-FU on gastric cancer cells in vitro and in vivo were studied. GSI combined with 5-FU was treated on gastric cancer cells, and then cell-proliferation by MTT assay, apoptosis by annexin V and expressions of protein level were determined by western blotting. Effects of GSI combined with 5-FU on tumor growth in vivo was assessed in an experimental model with orthotopically grown tumors. In gastric cancer cells, GSI combined with 5FU significantly inhibited cell proliferation and induced apoptosis. It was confirmed by expression changes of apoptosis related protein, such as caspase-3, caspase-8, caspase-9, PARP, BCL2, BID and BAX. GSI is also known to regulate PI3K/PTEN/AKT signaling pathway. After treatment with GSI plus 5-FU, this pathway was significantly down-regulated, and more, over-expression of constitutively activated AKT could prevent the apoptosis induction by combination treatment. This is suggested that the combination treatment with GSI plus 5-FU decreases the gastric cancer cell growth through inhibition of PI3K/PTEN/AKT signaling pathway. Moreover, administration of GSI in combination with 5-FU drastically reduced gastric tumor burdens in orthografted mice without prominent gastrointestinal toxicity. In conclusion, we present here that the combination treatment with GSI plus 5-FU has a potential for therapeutic activity in advanced gastric cancer patients.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 3506. doi:10.1158/1538-7445.AM2011-3506
Abstract 3507: Sulforaphane facilitates mitotic cell death triggered by arsenic trioxide
Authors: Yih Ling-Huei , Kuo Hsiao-Hui , Wu Yi-Chen
Published: June 2012

Arsenic trioxide (ATO) is an important antileukemic drug, but its use as a single agent in clinical trials against solid tumors was found to be mostly not effective or too toxic. Given the toxicity of chemotherapeutic agents, there is a considerable interest in the use of natural compounds with anti-tumorigenic properties for cancer treatment. In this study, we demonstrate that the cytotoxicity of ATO is significantly increased by cotreatment with non-toxic concentration of sulforaphane, an isothiocyanate found in cruciferous vegetables. The increased cytotoxicity was preceded by enhanced generation of reactive oxygen species and ATO-induced mitotic abnormalities and mitotic arrest. Consequently, sulforaphane facilitated mitotic cell death caused by ATO. However, neither zVADfmk (a pan caspase inhibitor) nor necrostatin (a necrosis inhibitor) prevented the cell death induced by the combined treatment indicating that caspase-dependent apoptosis or nercrosis is not involved in the enhanced cytotoxicity. In addition, no significant change on NF-κB-dependent transcription was observed at the non-toxic concentration used in this study indicating that sulforaphane did not exert the enhanced killing effect by inhibition of NF-κB. Since induction of mitotic arrest and mitotic cell death selectively kills highly proliferating cells, the enhanced mitotic cell death induced by cotreatment of ATO and sulforaphane provides a strategy to selectively kill cancer cells and to enhance the therapeutic efficacy of ATO.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 3507. doi:10.1158/1538-7445.AM2011-3507
Abstract 351: Tumor kinome profiling of early systemic disease dissemination in rectal cancer
Authors: Saelen Marie G. , Flatmark Kjersti , Folkvord Sigurd , de Wijn Rik , Rasmussen Heidi , Fodstad Oystein , Ree Anne H.
Published: June 2012

Tumor hypoxia as common determinant of resistance to cytotoxic therapies and metastatic behavior is an emerging hypothesis. In baseline tumor biopsy specimens from rectal cancer patients receiving preoperative chemoradiotherapy, using peptide arrays with 144 tyrosine kinase substrates, we have recently shown [Folkvord et al., Int J Radiat Oncol Biol Phys 2010] that phosphopeptide levels generated by tumors with poor response to the chemoradiotherapy were significantly higher than substrate phosphorylation resulting from tumors with good treatment response. The elevated kinase activity in poor-responding tumors was suppressed by the ex vivo addition of the tyrosine kinase inhibitor sunitinib and proved to represent signaling mediated by VEGFR, EGFR, and PI3K/AKT, which is known to be implicated in experimental radiation resistance. Given that these signaling pathways might be involved in adaptive responses to tumor hypoxia, this follow-up study aimed to determine whether the tumor kinase activity signatures might also correlate to systemic disease dissemination. Immunomagnetic detection of tumor cells in bone marrow aspirates was undertaken at the time of diagnosis, and bone marrow micrometastases (BMM) were observed in 33 of 55 (60%) of the patients from whom tumor kinase activity signatures had been obtained. In this new analysis, association between ex vivo sunitinib inhibition of the kinase activity and BMM status was studied, and phosphorylation of 31 tyrosine kinase substrates was significantly more strongly inhibited by sunitinib in the BMM negative patients than in the BMM positive individuals. Interestingly, discriminating phosphopeptides represented proteins derived from signaling pathways implicated in angiogenesis; e.g., signaling mediated by PDGFR, VEGFR, and EPOR, which is a central response to tumor hypoxia and fundamental for metastasis formation. At present, this patient cohort has a median follow-up of 41 months (range 13-58) and has demonstrated significantly poorer metastasis-free survival for the BMM-positive group than for the BMM-negative group (p = 0.008). In conclusion, in this cohort of rectal cancer patients, a tumor phenotype defined by a subset of tyrosine kinase activities insusceptible to the ex vivo inhibitory effect of sunitinib was associated with early systemic dissemination. This project was supported by the EU FP7 grant number 222741 (METOXIA).

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 351. doi:10.1158/1538-7445.AM2011-351
Abstract 3525: Targeting Group VIA phospholipase A2 using small molecules for ovarian cancer treatment
Authors: Xu Yan , Li Hui , Zhao Zhenwen , Antalis Caryl , Emerson Robert , Zhang Sheng , Zhang Zhongyin , Zhao Zhanzhong , Gang Wei , Yan Libo , Cai Qingchun
Published: June 2012

Epithelial ovarian cancer (EOC) causes estimated 13,850 deaths in 2010 in the United State. More effective treatment regimens are urgently required for this deadly disease. We and others have obtained ample evidence indicating that lysophosphatidic acid (LPA) plays an important role in EOC development. We have recently shown that the levels of LPA and several other bioactive lipids in the tumor environment of EOC are regulated by Group VIA calcium-independent phospholipase A2 beta (iPLA2β) expressed in tumor microenvironment, suggesting that targeting iPLA2β in both host and tumor cells will likely to be beneficial. To test this idea, we used bromoenol lactone (BEL), a selective inhibitor of iPLA2β in vivo, and found that BEL significantly inhibited EOC tumorigenesis and metastasis in mouse xenograft models using human SKOV3 and HEY ovarian cancer cells. Moreover, the combination of BEL with paclitaxel (PTX), one of the mostly commonly used therapeutics in EOC, almost completely blocked tumor development in the xenograft mouse model. BEL showed very low or no detectable cytotoxic effects in mice. Another iPLA2 inhibitor, FKGK11, also inhibited tumor development in the xenograft mouse model, supporting that the major target of action was iPLA2. The combinational effects of BEL and PTX in vivo likely stem from their distinct cellular effects. BEL and FKGK11 reduced adhesion, migration, and invasion of EOC cells in vitro; the reduced ability appears to increase the vulnerability of tumor cells to PTX. In summary, this is the first attempt to target iPLA2 using a small inhibitor molecule for cancer treatment in vivo. In addition, the work is also rather unique by targeting activity of the same molecule (iPLA2) in both host and tumor cells. These results provide an important basis for development of new treatment modalities for EOC.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 3525. doi:10.1158/1538-7445.AM2011-3525
Abstract 3567: Interaction of pralatrexate with the EGFR/MAPK pathway leads to synergistic activity with EGFR inhibitors
Authors: Serova Maria , Bieche Ivan , Vidaud Michel , Pronk Gijsbertus J. , Cvitkovic Esteban , Faivre Sandrine , Raymond Eric
Published: June 2012

Background: Pralatrexate (FOLOTYN®), an antifolate targeting dihydrofolate reductase, has high affinity for reduced folate carrier-1 and is an efficient substrate for polyglutamation by folypolyglutamyl synthetase. Combinations of cytotoxics and small molecule EGFR inhibitors (EGFRi's) have had little clinical success. Recent demonstration that intracellular folates may modulate survival signaling pathways, including EGFR/MAPK, suggests a potential for rational combinations of antifolates and EGFRi's. This study investigated potential roles of the EGFR/MAPK pathway in pralatrexate sensitivity and explored combinations of pralatrexate with EGFRi's.

Materials and Methods: Anti-proliferative effects of pralatrexate were evaluated in a panel of human cancer cell lines. mRNA expression was analyzed by qRT-PCR and protein was evaluated by Western blot. Effects of drug combinations were evaluated using the Chou & Talalay method.

Results: Pralatrexate displayed potent anti-proliferative effects in 9 of 15 human cancer cell lines, with HEP2 (head & neck [H&N]) and DU145 (prostate) cell lines showing IC50s of 50 nM and 15 nM, respectively. Sensitivity to pralatrexate correlated with higher pre-treatment mRNA expression of EGFR. After 5 hrs of exposure to 10 nM pralatrexate, increased phosphorylation of ERK1/2, MEK1/2, and the downstream target c-JUN was seen in HEP2 and DU145 cells. In addition, early activation of EGFR and EGFR protein degradation was observed. To further explore possible interactions between pralatrexate and the EGFR pathway, combination studies with EGFRi's were performed. Synergistic activity was observed in the MTT assay when pralatrexate was used in combination with erlotinib, gefitinib, and lapatinib in DU145, PC3, and LNCaP prostate and HEP2 H&N cancer cells. Synergistic activity was most pronounced when pralatrexate was given prior to the EGFRi's.

Conclusions: Higher expression of EGFR was associated with pralatrexate sensitivity in a panel of human cancer cell lines. Pralatrexate treatment resulted in activation of the EGFR/MAPK pathway. Sequential administration of pralatrexate followed by EGFRi's resulted in synergistic anti-tumor activity. These findings provide rationale for clinical evaluation of pralatrexate in combination with EGFRi's, in particular in tumors sensitive to antifolates and EGFRi's such as NSCLC and H&N cancer. In addition, evaluation of pralatrexate in combination with inhibitors of downstream EGFR targets is warranted.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 3567. doi:10.1158/1538-7445.AM2011-3567
Abstract 357: CYP3A4 Activates Stat3 in ER + breast cancer
Authors: Potter David A. , Guo Zhijun , Mitra Ranjana , Milani Monica , Rodriguez Mariangellys , Ding Li , Bliss Robin , Nguyen Julia , Luo Xianghua , Gupta Kalpna , Capdevila Jorge , Blair Ian , Thomas Dafydd , Bae Young K.
Published: June 2012

CYP3A4 expression in breast cancer has been reported to correlate with nodal metastases and decreased overall survival, but its mechanisms in cancer progression are unknown. ERalpha has been reported to promote CYP3A4 expression. We have previously demonstrated that CYP3A4 is an arachidonic acid (AA) epoxygenase that activates breast cancer cell proliferation through biosynthesis of 14,15-epoxyeicosatrienoic acid (EET).

Methods: Effects of 14,15-EET on Stat3 regulation were studied in MCF7 lines expressing CYP3A4 shRNA. Quantitative immunofluorescence (AQUA) interrogation of a tissue microarray was performed to evaluate CYP3A4 in cytoplasm, ERalpha and pY705Stat3 (pYStat3) in nuclei, and HER2 in cytoplasm/membrane. Values were transformed using the natural logarithm. These values were then averaged across the two spot sets. Pearson's correlation was calculated between the markers of interest.

Results: Stat3 (Tyr 705) phosphorylation is inhibited by CYP3A4 silencing. CYP3A4 synthesizes 14,15-EET in breast cancer cells and silencing of Stat3 blocks breast cancer cell growth and abrogates 14,15-EET-induced proliferation, indicating that CYP3A4 requires 14,15-EET biosynthesis and Stat3 to induce cell growth. Silencing of CYP3A4 reduces nuclear pY705-Stat3, while 14,15-EET restores this signaling process. By preliminary immunofluorescence study of consecutive breast cancers (n=48) nuclear ERalpha was associated with cytoplasmic CYP3A4 with a correlation of r=0.7575 (p-value < 0.0001). Cytoplasmic CYP3A4 correlated with nuclear pYStat3, with a correlation of r=0.2708, approaching statistical significance (p = 0.0656). Cytoplasmic/membrane HER2, known to be induced by Stat3, was associated with nuclear pYStat3, exhibiting a correlation of r=0.4460 (p-value = 0.0015).

Conclusions: ER+ breast cancer cell growth is therefore mediated, in part, by CYP3A4 biosynthesis of 14,15-EET that induces nuclear pY705-Stat3. These studies indicate that CYP3A4 is an AA epoxygenase that is expressed in ER+ breast cancer and promotes Stat3-mediated breast cancer cell growth, in part, through 14,15-EET biosynthesis. Activated Stat3 may mediate cytoplasmic/membrane HER2 expression.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 357. doi:10.1158/1538-7445.AM2011-357
Abstract 3575: Dovitinib (TKI258), a dual inhibitor of FGFR and VEGFR, induces tumor growth suppression in xenograft models of human bladder cancer
Authors: Shi Michael M. , Linnartz Ronald , Versace Richard , Brueggen Joseph , Chatenay-Rivauday Christian , Stamm Christelle , Dugan Margaret , Porta Diana Graus
Published: June 2012

Introduction: The aim of this study was to evaluate the efficacy of dovitinib (TKI258), a small molecule dual inhibitor of fibroblast growth factor receptor (FGFR) and vascular endothelial growth factor receptor (VEGFR) in mouse models of human bladder cancer. Molecular epidemiological studies have implicated FGFR and VEGFR pathways in the pathogenesis of high grade, muscle invasive bladder cancer. Somatic activating mutations in FGFR3 have been identified in 16%-20% of muscle-invasive bladder cancer and FGFR3 overexpression has also been documented in a high fraction of bladder cancers. High microvessel density, serum VEGF levels and urine FGF2 levels have also been associated with high grade bladder cancer and poor disease-free survival. Dual FGFR/VEGFR inhibitory activities of dovitinib make it an attractive molecule targeting advanced bladder cancer. Experimental Design: Dovitinib was evaluated in the RT112 human bladder carcinoma xenograft model. Dovitinib was administered orally at three dose levels (n = 10/group), once daily for 28 consecutive days (qd × 28). A rat RT112 xenograft study was also carried out to evaluate the PK/PD effect of single dose dovitinib administration. Results: Dovitinib at 15, 30, and 60 mg/kg resulted in tumor growth suppression, with mean changes of 60% T/C, 6% T/C (P < 0.01), and -71% T/T0 (P < 0.001), respectively. The 60 mg/kg regimen yielded 6 partial regressions out of 10 animals by day 28. In the rat RT112 model, dovitinib caused dose- and time-dependent inhibition of pFRS2 at 25 and 50 mg/kg after 3, 7 and 24 h of a single oral dose administration. Conclusion: Dovitinib demonstrated significant antitumor effect in a mouse model of human bladder cancer xenograft. This study provides a strong rationale for clinical investigation of dovitinib in patients with advanced bladder cancer.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 3575. doi:10.1158/1538-7445.AM2011-3575
Abstract 3578: A novel and selective 3-phosphoinositide-dependent kinase-1 inhibitor, PF-5177624, blocks insulin-like growth factor-1 induced tumorigenesis in breast cancer cells
Authors: Baxi Sangita M. , Walls Marlena , Murphy Sean , Ermolieff Jacques , Smeal Tod , Yin Min-Jean
Published: June 2012

Phosphatidylinositol 3-kinases (PI3Ks) phosphorylate membrane phosphatidylinositides to generate phosphatidylinositol 3,4,5-triphosphate (PIP3); PIP3 serves as an important secondary messenger recruiting and activating proteins that contain a pleckstrin homology (PH) domain including AKT and 3’-phosphoinositide-dependent kinase-1 (PDK1). PDK1 is a 63-kDa Ser/Thr kinase with a catalytic domain near its N-terminus and a pleckstrin homology domain at its C-terminus. The PH domain is necessary for targeting PDK1 to the plasma membrane to phosphroylate the T-loop sites of numerous substrates such as AKT at the residue threonine-308 (T308). The phosphorylation at both T308 and the serine-473 residue by mTORC2, fully activates AKT to induce the downstream signaling pathways that are important for tumor progression. PDK1 also has been shown to phosphorylate p70S6K, isoforms of PKCs, and many other kinase substrates. The oncogenic activity of aberrant PI3K pathway signaling through PDK1 has been extensively validated. PDK1 is highly expressed in a majority of human breast cancers and cell lines, and elevated phosphorylation of PDK1 was associated with PIK3CA mutations in human breast tumors and cell lines. Therefore, targeting PDK1 in the PI3K/AKT pathway may provide an opportunity for breast cancer treatment.

In this study, we demonstrate that insulin-like growth factor-1 (IGF-1) stimulates PDK1 activity and a specific and potent PDK1 inhibitor, PF-5177624, inhibits IGF-1 stimulated downstream signaling in breast cancer cells, including a reduction in phosphorylation of both AKT (T308) and p70S6K. The inhibition of PDK1 activity through the IGF-1 axis is sufficient to induce in vitro anti-tumor activity in breast cancer cells such that PF-5177624 inhibits cell proliferation and cell transformation in breast cancer cells. Our data suggest that a specific and potent PDK1 inhibitor (PF-5177624) is likely to have antitumor activity in breast cancer cells and can be developed as a cancer drug for breast cancer patients.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 3578. doi:10.1158/1538-7445.AM2011-3578
Abstract 3584: Effects of the investigational selective MEK inhibitor TAK-733 against cutaneous and uveal melanoma cell lines
Authors: von Euw Erika , Atefi Mohammad , Attar Narsis , Zachariah Sybil , Burgess Barry L. , McCannel Tara , Lichter David I. , Izmailova Elena , Ribas Antoni
Published: June 2012

Background. There are several MEK inhibitors currently under clinical investigation, including, TAK-733, a novel non-ATP-competitive allosteric selective inhibitor of MEK. We have analyzed the sensitivity of human melanoma cell lines of different origins to TAK-733.

Methods. The half maximal inhibitory concentration (IC50) of TAK-733 was assessed in a panel of 27 skin melanoma cell lines and 5 ocular melanoma cell lines genotyped for driver and secondary oncogenic mutations. Flow cytometry was used to analyze effects on cell cycle progression, and Western blots to analyze the downstream signaling changes upon exposure to TAK-733.

Results. Among 12 BRAFV600E mutated cell lines tested, 6 were sensitive to TAK-733 with IC50s less than 10 nM, including 4 highly sensitive cell lines with IC50s below 1 nM. In 5 cell lines with BRAFV600E mutation the IC50 was higher than 100 nM and were considered highly resistant. Among 10 NRASQ61L mutant melanoma cell lines, 6 were sensitive with IC50s below 10 nM. Among 5 melanoma cell lines with wild type sequences for NRAS, BRAF, GNAQ and GNA11 genes only 1 was sensitive to TAK-733. All 5 of the uveal melanoma cell lines were highly sensitive to TAK-733 IC50 regardless of having a GNAQ or GNA11 mutations. MEK inhibition resulted in increase of pMEK more prominently in NRASQ61L mutant and GNAQ mutant cell lines than in BRAFV600E mutant cell lines. In all cases TAK-733 induced marked dose-dependent inhibition of pERK, regardless of the driver oncogenic mutation or the sensitivity or resistance to this agent in cell viability assays. Cell lines resistant to TAK-733 showed no inhibition of pAKT or pS6K, while there was a general trend towards inhibition of these two phosphorylated molecules in sensitive cell lines.

Conclusions. TAK-733 is a potent MEK inhibitor with high antitumor activity against human melanoma cell lines with BRAF, NRAS, GNAQ and GNA11 driver mutations.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 3584. doi:10.1158/1538-7445.AM2011-3584
Abstract 3631: NMDA receptors as possible therapeutic targets for cancer
Authors: Akerman Bonnie L. , Allen Chenoa D. , Sylvain Nathan P. , North William G.
Published: June 2012

NMDA receptors constitute important calcium channels that are chiefly found within the central nervous system. Our laboratory has shown that these receptors are also expressed by human tumors such as neuroblastoma, small-cell lung carcinoma, breast cancer, and now ovarian and prostate cancer. The hypothesis being tested in our studies is that selective tumor expression of NMDA receptors is essential for cancer cell growth and proliferation. Human breast and ovarian cancer cells were treated with NMDA antagonists and agonists and changes measured in cell proliferation/growth and apoptosis. It was shown NMDA receptors are critically involved in cell growth of these cancer cells, and if blocked, cell growth is inhibited. Interestingly, the non-cancerous cell line, HEK 293, also expresses NMDA receptors, but NMDA antagonists were found to not influence growth of these cells. Receptor knock-down in MCF-7 breast cancer cells is being accomplished with lentavirus-coupled shRNAs, and selection performed for puromyocin resistance. We have thus far been able to selectively stably reduce NMDA receptor expression by 70-80% for a period of two weeks. The rate of cell growth was significantly decreased when the expression level of NMDAR1 is knocked down. The response of NMDA receptor knock-down cells to antagonists such as MK-801 and Mementine will be examined. Confirmation that the actions of antagonists such as MK-801 on cancer growth are specifically due to blockade of NMDA receptors will further their potential future use in cancer treatment. By confocal microscopy we were able to demonstrate that breast, ovarian, and prostate cancer cells express NMDA receptors within the membrane of tumor cells. Treating breast cancer cells with NMDA receptor antagonists and an antibody against an extracellular region of the subunit 1 changes the sub-cellular localization of these NMDA receptors. This change in sub-cellular localization could be an indicator of the mechanism of action of these compounds on cancer cell growth through the expression levels of the receptors. Additional studies are now being performed using sub-cellular fractionation and fluorescent microscopy to determine the nature of NMDAR1 cellular translocalization. The goal of this project is to further evaluate NMDA receptors as possible targets for treatment of breast cancer and perhaps several other cancer types.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 3631. doi:10.1158/1538-7445.AM2011-3631
Abstract 3637: MM-302, a HER2-targeted liposomal doxorubicin, shows binding/uptake and efficacy in HER2 2+ cells and xenograft models
Authors: Klinz Stephan , Eckelhofer Isabelle , Gaddy Daniel , Geretti Elena , Hendriks Bart , Lee Helen , Leonard Shannon , Reynolds Joe , Wickham Tom
Published: June 2012

Introduction: MM-302 is an ErbB2/HER2-targeted liposomal doxorubicin formulation designed to target doxorubicin to HER2-overexpressing cancer cells while limiting uptake into non-target cells. The characterization of the binding and uptake of MM-302 as a function of HER2 surface levels on various cell lines and in tumor models will help determine the minimum HER2 receptor levels required for MM-302 patient selection.

Methods: Cellular models included 16+ established human tumor cell lines as well as 4T1 murine breast cancer and HeLa human cervical cancer cells engineered to overexpress HER2 from 1E05-1E06 receptors/cell. Cells were incubated with MM-302, untargeted liposomes or free doxorubicin and binding/uptake was measured by HPLC or flow cytometry. In vivo efficacy was determined in select mouse xenograft models. Tumors were mechanically and enzymatically dissociated, followed by flow cytometry to quantify the uptake of targeted and untargeted liposomes into HER2-expressing tumor cells, macrophages and other cell types.

Results: Binding and uptake of MM-302 increased with rising HER2 surface levels in cells of common parental origin (4T1, HeLa), with significant uptake into cells with >2E05 HER2/cell. Further, total cell binding/uptake of MM-302 also increased with rising HER2 expression across a panel of 16+ cell lines. There was negligible uptake of untargeted liposomes under all conditions that showed no dependence on HER2 expression. Improved anti-tumor efficacy of MM-302 was observed in BT474-M3 and NCI-N87 mouse xenograft models relative to untargeted liposomal doxorubicin and free doxorubicin. Further, using disaggregated tumors, the relationship between HER2 expression and MM-302 uptake was confirmed in vivo in both models.

Conclusions: Our studies identified a HER2 threshold for uptake of MM-302 of approximately 2E05 receptors/cell, and suggest a role for MM-302 not only in HER2 3+ cancers, but also in HER2 2+ cancers as well. The ability to treat HER2 2+ tumors offers an exciting opportunity to serve a major unmet clinical need.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 3637. doi:10.1158/1538-7445.AM2011-3637
Abstract 3677: Prediction of oral cancer recurrence at post-surgery follow-up using fluorescence visualization
Authors: Poh Catherine F.Y , Wu Lang , Ko Kevin , Williams P. Michele , Rosin Miriam P.
Published: June 2012

Background: Recurrence is observed in up to 30% of surgically treated high-risk oral lesions (HRLs, severe dysplasia, carcinoma in situ and cancer) and is associated with poor prognosis. Reactive tissue change observed post-treatment often masks recurrence and makes early detection difficult. New advances using fluorescence visualization (FV) represent a promising approach to this problem that may facilitate early detection of disease recurrence.

Objectives: 1) To identify FV alterations post-treatment of HRLs and 2) To determine whether a relationship exists between FV alterations and local recurrence.

Methods: In the BC Oral Cancer Longitudinal Study, we have recruited ∼400 HRLs with surgical treatment as the primary modality. Patients eligible for this analysis included those that had an initial follow-up appointment within 6 months of surgery with at least 2 follow-up appointments within the first year of treatment, with each visit involving FV examination of the treatment site. Recurrence was defined as the presence of biopsy-proven HRLs. The ‘plateau’ of the FV during the follow-ups is defined as the change of FV measurement in width within ± 1 mm (superior-inferiorly) in various time intervals of 3, 6, 9, or 12 months.

Results: A total of 198 patients were identified of which 24 (12%) had lesion recurrence at the previously treated site. There was no difference in gender, age, ethnicity, smoking habit, anatomical site, primary diagnoses, and follow-up time between the recurrence and non-recurrence groups. The duration of plateau was longer in non-recurrence group compared to those in recurrence group (P = 0.03). When we examined the duration ‘plateau’ at various intervals of follow-ups, among 166 patients/lesions with at least 9 months follow-ups, we found out that the presence of plateau was more frequent in the non-recurrence group than those recurrent case (P = 0.03). Using linear mixed effects and logistic regression analyses, there was a significant difference of the individual slopes between recurrence and non-recurrence group (P = 0.001), adjusted for the individual intercepts (i.e., the original FV width).

Conclusion: The stability, i.e., timing and duration of the plateau, of the FV alteration during post-surgical follow-ups can be potentially used to predict local recurrence of HRLs.

(Supported by Supported by grant R01 DE17013 from the National Institute of Dental and Craniofacial Research and grant CCSRI-20336 from Canadian Cancer Society Research Institute; Canadian Institute for Health Research and Michael Smith Foundation from Health Research)

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 3677. doi:10.1158/1538-7445.AM2011-3677
Abstract 3689: Targeting cell survival pathways with the combination of honokiol and resveratrol for prevention of head and neck cancer
Authors: Amin A.R.M. Ruhul , Jung Kyung-Ho , Wang Dongsheng , Arbiser Jack L. , Chen Zhuo G. , Shin Dong M.
Published: June 2012

Natural dietary agents have drawn great attention for cancer prevention because of their wide safety margin and ready availability. However, single agent intervention has failed to bring the expected outcomes in clinical trials. In the current study, we investigated a combinatorial approach using two natural compounds, honokiol (isolated from the bark of the magnolia tree) and resveratrol (a major constituent of red wines and grapes), and found that their combination at low doses (at which single agents induce minimal cell growth inhibition) strongly inhibited cell growth as measured by SRB assay. Moreover, the combination of low dose honokiol (which alone induces 10-15% apoptosis) with low dose resveratrol (also induces ∼10% apoptosis) strongly increased apoptosis (to 60-80%) in multiple head and neck cancer cell lines as evidenced by annexin V-PE staining and PARP cleavage. Interestingly, normal human fibroblasts (BJ) or immortalized normal bronchial epithelial cells (BEAS-2B) were resistant to apoptosis induced by the combination of the two compounds (less than 10% apoptosis). To understand the mechanism of apoptosis, we fractionated cytosolic and mitochondrial fractions to study the release of cytochrome c from the mitochondria to the cytosol, and found that the combination of honokiol and resveratrol more efficiently caused release of cytochrome c compared with either single agent alone. Further mechanistic studies suggested that the combination of the two agents inhibited phospho-STAT3 and phospho-AKT and reduced NF-κB protein level more efficiently than either single agent. Moreover, although single agent treatment has only minimal effect on expression of NF-κB and the STAT3 targets Bcl-2, Mcl-1 and survivin, the combination of the two agents strongly inhibited expression of these proteins, further supporting the involvement of mitochondria-mediated apoptosis. However, expression of Bcl-xL, another proapoptotic Bcl-2 protein remained unchanged after treatment with the compounds. We also found transient inhibition of phospho S6 kinase, a downstream target of p-AKT. NF-κB, phospho-STAT3 and phospho-AKT pathways are frequently over-active in head and neck cancer, suggesting that the combination of honokiol and resveratrol might be an effective strategy for the prevention of head and neck cancer and providing an important rationale for future preclinical and clinical development. (Supported by U01CA101244, R01CA112643, and P50CA128613 to DMS)

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 3689. doi:10.1158/1538-7445.AM2011-3689