bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract PR-9: Differences in effects on myocardium and mitochondria by VEGF receptor inhibitors suggest separate mechanisms of cardiotoxicity
Authors: French Kevin , Hu Catherine , Kumar Rakesh , Renninger Jon , Gales Tracy , Coatney Robert , Frazier Kendall
Published: June 2012

Reports have implicated vascular endothelial growth factor receptor (VEGFR) tyrosine kinase inhibitors with mitochondrial injury and/or subsequent cardiovascular toxicity, suggesting an on-target pharmacologic effect by this class of promising anticancer agents. Investigative studies were performed to assess myocardiotoxicity and mitochondrial toxicity of 3 VEGFRi's (sunitinib, sorafenib and pazopanib). Mitotoxicity was evaluated in vitro using Laser Scanning Cytometry in neonatal rat ventricular myocyte cultures with endpoints including mitochondrial membrane potential (MMP), cell viability, apoptosis and ATP depletion. Cardiomyocytes were exposed with protein free concentrations of up to 4 micromolar of sunitinib, sorafenib or pazopanib for 48 hours. There were no changes in viability or apoptosis versus vehicle-treated cells. Mitochondrial membrane potential was slightly but significantly decreased with sunitinib treatment but not with sorafenib nor pazopanib. Dose-dependent intracellular ATP depletion was observed with sunitinib and sorafenib, but not with pazopanib. In separate in vivo studies, echocardiographic, histomorphologic and ultrastructural approaches were used to assess cardiotoxicity in rats concurrently exposed to the cardiac stressor dobutamine and one of the VEGFR inhibitors in rats for 21 days. Troponin I and TUNEL were also evaluated and were similar to controls. While hearts were morphologically unremarkable by routine microscopic examination, ultrastructural analysis of myocardiocytes by electron microscopy revealed mitochondrial swelling, dense deposits and matrix cavitation in 6/8 rats given sunitinib, disrupted mitochondrial cristae in 1/7 given sorafenib, but no effects with pazopanib. Echocardiographic abnormalities including premature ventricular contractions, alterations in heart rate, circumferential strain, and radial and circumferential strain rates were also noted with sorafenib, but not with sunitinib or pazopanib after dobutamine stress challenge. Our results indicate there are marked differences in the potential for myocardial toxicity and mitochondrial toxicity between VEGFR inhibitors. Since sunitinib and sorafenib have previously been shown to have differential effects on mitochondria, the mechanism of cardiac/mitochondrial injury with various VEGFRi's may not be a result of similar class-based VEGFR2 pharmacology, but instead reflect separate kinase selectivity profiles.

Citation Information: Mol Cancer Ther 2009;8(12 Suppl):PR-9.
Abstract A119: Photoimmunotherapeutic nanoparticles for combination therapy.
Authors: Dhar Shanta , Williams Anna M.
Published: June 2012

Photoimmunotherapy (PIT) is a promising field for cancer treatment that combines the phototoxic and immune stimulating ability of photodynamic therapy (PDT) with the widespread effectiveness of the immune system. We speculated that co-delivery of an immune-stimulant with a photosensitizer (PS) using a nanoparticle (NP) delivery platform will be a useful means to attack metastatic cancer. To probe this, we have initiated the construction of new PIT agents using a multifunctional NP delivery platform. Briefly, we encapsulated a PS within a polymeric NP core made up of poly(D,L-lactic-co-glycolic acid)-b-poly(ethylene glycol) (PLGA-b-PEG). After coating the outside of the polymeric core with gold nanoparticles, we modified the gold surface with CpG-ODN, a single-stranded DNA that is a known immunostimulant. Synthesis, biological activity, and immune stimulatory effects of these constructs will be presented.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2011 Nov 12-16; San Francisco, CA. Philadelphia (PA): AACR; Mol Cancer Ther 2011;10(11 Suppl):Abstract nr A119.
Abstract A133: A novel class of selective estrogen receptor degraders regresses tumors in preclinical models of endocrine-resistant breast cancer.
Authors: Darimont Beatrice , Govek Steven , Joseph James , Grillot Katherine , Bischoff Eric , Aparicio Anna , Bonnefous Celine , Douglas Karensa , Julien Jackline , Kahraman Mehmet , Kaufman Joshua , Lai Andiliy , Lee Kyoung-Jin , Lu Nhin , Nagasawa Johnny , Prudente Rene , Qian Jing , Sensintaffar John , Shao Gang , Heyman Richard , Rix Peter , Smith Nicholas , Hager Jeffrey
Published: June 2012

60–75% of all breast cancers express the estrogen receptor (ER) and thus are treated with anti-hormonal therapies that directly block ER function (e.g. Tamoxifen) or hormone synthesis (Aromatase Inhibitors). While these therapies are initially effective, acquired resistance invariably emerges. Importantly, the majority of these tumors continue to express and depend on ER for growth and survival, suggesting that novel approaches to target ER signaling have tremendous potential to treat endocrine-resistant disease. We have identified novel ER antagonists that induce degradation of ER at picomolar concentrations resulting in significant reduction in steady state ER protein levels in breast cancer cell lines. These compounds yield regression in both Tamoxifen-sensitive and - resistant models of breast cancer in vivo. Based on their unique in vitro profile, good pharmacokinetics and oral bioavailability, these compounds represent a novel class of Selective Estrogen Receptor Degraders (SERDs) that hold tremendous promise as a next generation therapy for the treatment of ER+ breast cancer.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2011 Nov 12-16; San Francisco, CA. Philadelphia (PA): AACR; Mol Cancer Ther 2011;10(11 Suppl):Abstract nr A133.
Abstract A14: Patient-derived tumor xenografts supporting development of targeted drugs.
Authors: Hoffmann Jens , Becker Michael , Jana Rolff , Rivera Maria , Merk Johannes , Zeisig Reinhard , Schlag Peter M. , Schwan Alexandra , Fichtner Iduna
Published: June 2012

Almost in parallel with the new millennium processes in drug development for cancer therapy have changed substantially. Insight in the cancer biology have revealed this disease as a complex genetic disorder leading to a high variety of phenotypes among the different individuals. Many tumors present a very specific pattern of molecular changes and this leads to a heterogenous individual response to drugs.

The correct identification of predictive biomarkers selecting the most appropriate therapies and avoiding unnecessary treatments for an individual patient is still a challenge. Patient-derived tumor xenografts allow preclinical investigations in a clinically relevant way. We performed investigations to improve the understanding of cancer complexity and to draw rational conclusions for therapy decisions.

Tumor models were established by direct transplantation of surgical specimens to immunodeficient mice and were maintained in early passages. We have shown a high correlation between original patient sample and xenograft both at gene and protein level. We established several large panels of tumor models: i.e. 10 breast, 30 colorectal, 25 lung, 6 ovarian, 10 sarcomas, and 30 leukemias (25 ALL and 5 AML).

During the characterization of the xenografts for response towards clinically used anticancer drugs, the analysis for mutations and of gene expression revealed interesting correlations. In NSCLC models upregulation of hypoxia marker genes correlated with resistance to microtubule targeted drugs. In the colon cancer xenografts KRAS mutations predicted resistance to cetuximab.

We further identified a potential set of 20 genes which may be predictive for oxaliplatin response. These results demonstrate, that the ability to assess anti-tumor activity in well-characterized xenografts in correlation with particular genetic or molecular characteristics may support the development of new therapeutic regimens.

Conclusions from what we discussed are:drug discovery, systems biology, and translational research are moving together to address all the new hallmarks of cancer - increasing the success rate of drug discoverypanels of patient derived xenograft models represent an important tool for translational research to address clinically relevant questions in a standardized and strictly controlled fashionpredictive value of the preclinical models is increasing steadily - they show a high concordance with the clinical specimens concerning marker expression and response to therapy

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2011 Nov 12-16; San Francisco, CA. Philadelphia (PA): AACR; Mol Cancer Ther 2011;10(11 Suppl):Abstract nr A14.
Abstract A159: Epigenetic silencing of the M-type phospholipase A2 receptor gene in leukemic cells.
Authors: Menschikowski Mario , Platzbecker Uwe , Hagelgans Albert , Vogel Margot , Thiede Christian , Schoenefeldt Claudia , Eisenhofer Graeme , Siegert Gabriele
Published: June 2012

Background: The M-type phospholipase A2 receptor (PLA2R) plays a crucial role in a number of different signaling pathways and may act as tumor-suppressor. In the current study the expression and methylation of the PLA2R gene in the myeloid U937 cell line and blood leukocytes of patients with leukemia were analyzed. Methods. Expression of PLA2R in U937 cells was studied using RT-quantitative PCR. To determine methylation levels of the PLA2R locus, bisulfite-modified DNA fragments were sequenced. Identification of different 5′-CpG methylation sites in normal and leukemic patients was followed by methylation specific-high resolution melting (MS-HRM) analysis to quantify PLA2R methylations.

Results: Our data establish that expression of PLA2R is completely down-regulated in U937 cells. Simultaneously, a 100% methylation of PLA2R promoter and down-stream regions was found in this cell line; after exposure of the cells to 5-aza-2 -deoxycytidine, PLA2R was re-expressed. MS-HRM analyzes in 34 patients with different types of leukemia indicated an average PLA2R methylation of 30%±18%, whereas in 52 normal subjects methylation levels were below 10%. In a preliminary study of high-risk myelodysplastic syndrome patients (MDS), three patients had increased PLA2R methylations. In the course of treatment with azacitidine (Vidaza) as methyltransferase inhibitor, two of these patients were responders in contrast to one patient who was a non-responder with increased methylation levels in blood leukocytes during treatment. Another patient with minimal residual disease after treatment of AML underwent preemptive treatment with azacitidine to avoid hematological relapse (HR). After two azacitidine cycles a minor cell fraction with 100% methylated PLA2R was completely diminished. However, three weeks later methylation of the PLA2R promoter increased to 50%, with 9% blasts detectable in blood samples. After further azacitidine treatment cycle, blasts diminished in blood samples but the methylation of PLA2R in blood leukocytes remained at 35%. During the following seven weeks with no further azacitidine treatment blasts increased up to 44% suggesting that the treatment with azacitidine was effective but not efficient enough to prevent a HR in this patient.

Conclusions: The study shows for the first time that the PLA2R promoter and down-stream regions in leukemic cells are hypermethylated and that the determination of PLA2R methylation by MS-HRM may be useful as a biomarker in the diagnosis and therapeutic treatment of high-risk MDS and AML patients.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2011 Nov 12-16; San Francisco, CA. Philadelphia (PA): AACR; Mol Cancer Ther 2011;10(11 Suppl):Abstract nr A159.
Abstract A181: IGF-IR expression predicts responsiveness to ionizing radiation in patients with locally advanced cervical cancer.
Authors: Moreno-Acosta Pablo , Cendales Ricardo , Gamboa Oscar , Romero Alfredo , Serra Joseph Balart , Magne Nicolas
Published: June 2012

Background: The aim of the present study was to evaluate a possible association of expression IGF-IR, IGF-I, IGF-II, GAPDH and hemoglobin levels with tumor response to radiotherapy alone in patients HPV 16 positive with locally advanced cervical cancer.

Methods: In this study of case-control nested in a cohort, 38 patients were included to whom tumor sample in fresh of the transformation zone of cervix was taken them before treatment. All of them were treated with exclusive pelvic external beam radiotherapy plus intracavitary brachytherapy. Response was defined as no evidence of residual disease after clinical examination by measuring tumor size, three months after the completion of the therapeutic sequence. Gene expression levels before radiotherapy were compared between complete response and non response.

Results: A major increase was observed in gene expression IGF-IR (34%), followed by the expression of IGF-II (24%) in the cases of cancer in comparison with either the control group or normal tissue samples of the transformation zone of cervix obtained from non-oncologic patients treated by hysterectomy. GAPDH expression was directly correlated with the IGF-IR & IGF-II co expression under hemoglobin lower than 11g/dl (p=0.05). Patients with IGF-IR expression had 26.8 times more risk of treatment failure (p=0.018).

Conclusion: This is the first report in the clinical setting that relates the expression of IGF-IR as a strong marker of responsiveness. Therefore, the IGF-IR can be considered as a molecular target for optimizing the treatment of cervical cancer with radiotherapy.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2011 Nov 12-16; San Francisco, CA. Philadelphia (PA): AACR; Mol Cancer Ther 2011;10(11 Suppl):Abstract nr A181.
Abstract A199: The plekstrin-homology-domain-containing protein PLEKHA7 is a novel target for selectively inhibiting mutant KRAS colon cancer cell proliferation.
Authors: Jeung Hei-Cheul , Kiriakova Galina , Kirkpatrick Lynn , Indarte Martin , Powis Garth
Published: June 2012

KRAS harbors oncogenic mutations that yield a constitutively active protein in approximately 40% of colorectal cancer. Randomized clinical trials have indicated that the wild-type KRAS (wt-KRAS) is predictive for resistance to anti-EGFR therapy and there is currently no effective therapy for mutant KRAS (mut-KRAS) tumors that is associated with a poor prognosis. Therefore, mut-KRAS tumors are an unmet medical need in colorectal and other cancers. In a search for target genes that when down-regulated selectively inhibit the growth of cells with mut-KRAS but not the cells without mut-KRAS, we used a global synthetic lethal small interfering RNA screen of MiaPaCa-2 and HCT-116 cells (mut-KRAS). The screen identified the gene encoding PLEKHA7 (pleckstrin homology (PH) domain containing, family A member 7). Other PLEKHA family members did not show this effect. PLEKHA7 is a component of the epithelial adherens junction belt that links E-cadherin to the cytoskeleton, and through which KRAS may signal its effects on cell proliferation, invasion and metastasis. PLEKHA7 and KRAS levels were measured by RT-PCR in a panel of 23 colon cancer cell lines (10 wt-KRAS and 13 mut-KRAS) and showed a positive correlation with KRAS levels (R2 = 0.943), and a Wilcoxon Rank test showed that the median expression of PLEKHA7 was higher in cell lines with mut-KRAS than with wt-KRAS (P=0.02). Targeted knockdown of PLEKHA7 using siRNA resulted in growth inhibition for mut-KRAS cells (HCT116, DLD-1, SK-CO-1, SW480, HCT15, and LOVO), but not for wt-KRAS cells (SW48, CACO-2, SW1417, and HT29). Paradoxically, targeted knock-down of KRAS caused an increase in PLEKHA7 mRNA levels in mut-KRAS cells. PLEKHA7 contains a PH-domain in a three-dimensional protein fold that binds to plasma membrane phosphoinositide-3-phosphates (PIP3) formed by phosphatidyl-3-phosphate kinase. We have previously shown that PH-domains can be selectively targeted by small molecules, blocking the binding to PIP3, and inhibiting the function of PH-domain proteins such as Akt and PDPK1. The findings of the present study imply that PLEKHA7 offers a potentially druggable target for inhibiting mut-KRAS-related signaling and cancer-related functions, providing an approach for inhibiting cancer progression of colorectal cancer with KRAS mutation.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2011 Nov 12-16; San Francisco, CA. Philadelphia (PA): AACR; Mol Cancer Ther 2011;10(11 Suppl):Abstract nr A199.
Abstract A203: Identification of FoxM1/Bub1b signaling pathway as a molecular target in rhabdomyosarcoma.
Authors: Wan Xiaolin , Yeung Choh , Kim Su Young , Asaudt Louis M. , Helman Helman J.
Published: June 2012

Rhabdomyosarcoma (RMS) is the most common pediatric soft tissue sarcoma. Intensive multi-modal therapeutic regimens have increased overall survival in the last 25 years, but 25% of patients still succumb to disease, thus necessitating the identification of novel targets for therapy. In this study, we identified that Bub1b is necessary for the growth and survival of both ARMS and ERMS cells using a loss of function high-throughput shRNA screen. Using many additional Bub1b shRNA sequences, we were able to confirm that human RMS cells were more sensitive to Bub1b knockdown compared to human fibroblasts or human ovarian cancer cells. Knockdown of Bub1b also resulted in significant suppression of RMS xenografts growth in vivo. Mechanistically, flow cytometry analysis of knockdown Bub1b cells had an increase in >4N DNA content. Live-cell time-lapse microscopy studies provided direct evidence that knockdown of Bub1b promotes endoreduplication, eventually causing mitotic catastrophe. Further, ChIP assay demonstrated that Forkhead Box M1 (FoxM1), an essential transcriptional factor for G1/S transition and mitotic progression, directly binds to the Bub1b promoter. Luciferase reporter assay showed that FoxM1-binding region is critical for the activation of the Bub1b promoter. Suppression of FoxM1, either by shRNA or the inhibitor siomycin A, led to reduction of Bub1b expression and inhibition of cell growth and survival in vitro. These findings indicate that the FoxM1-Bub1b axis is important for the growth and survival of RMS cells and may be a target for RMS therapy in the future.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2011 Nov 12-16; San Francisco, CA. Philadelphia (PA): AACR; Mol Cancer Ther 2011;10(11 Suppl):Abstract nr A203.
Abstract A227: Antitumor activities of ASP3026 against EML4-ALK-dependent tumor models.
Authors: Kuromitsu Sadao , Mori Masamichi , Shimada Itsuo , Kondoh Yutaka , Shindoh Nobuaki , Soga Takatoshi , Furutani Takashi , Konagai Satoshi , Sakagami Hideki , Nakata Mari , Ueno Yoko , Fushiki Hiroshi , Saito Rika , Sasamata Masao , Mano Hiroyuki , Kudou Masafumi
Published: June 2012

EML4-ALK is an oncogenic fusion kinase, which was first identified in non-small cell lung cancer (NSCLC), and is regarded as an attractive therapeutic target for treating a subpopulation of NSCLC patients. Crizotinib, which is inhibitor for MET and ALK, was recently approved by FDA (26 August 2011) for patients with locally advanced or metastatic non-small cell lung cancer (NSCLC) that is anaplastic lymphoma kinase (ALK)-positive as detected by an FDA-approved test.

We synthesized and screened chemical compounds utilizing an ALK kinase inhibition assay aimed at the EML4-ALK target for drug discovery, and found ASP3026, a novel and selective inhibitor for the ALK kinase. ASP3026 potently inhibited ALK kinase activity and was more selective than crizotinib in a Tyr-kinase panel. In an anchorage independent in vitro cell growth assay, ASP3026 inhibited the growth of NCI-H2228, a human NSCLC tumor cell line endogenously expressing EML4-ALK variant 3 and that of 3T3 cells expressing EML4-ALK variant 1, 2 and 3. The plasma and tumor concentrations of ASP3026 in mice xenografted with NCI-H2228 tumor were determined using high-performance liquid chromatography-tandem mass spectrometry. Significant tumor penetration was observed. The antitumor activities were evaluated using mice bearing subcutaneous NCI-H2228 tumor xenografts. ASP3026, (daily oral dosing for 14 days) induced dose dependent anti-tumor effects starting at 1 mg/kg with marked regression at 10, 30 and 100 mg/kg. Body weights were unaffected. Crizotinib, (twice daily oral dosing) was less potent, with growth inhibition at 10 mg/kg, and tumor regression at 30 mg/kg. A dose of 100 mg/kg of crizotinib was poorly tolerated. Resistance mutations in ALK kinase domain against crizotinib were reported following sequence analysis of tumor cells derived from crizotinib-relapsed patients. The position of the mutation is the so-called gatekeeper mutation and is thought to be one of the causes of crizotinib relapse. In an EML4-ALK driven tumor model with gatekeeper mutation, ASP3026 showed potent anti-tumor effects while crizotinib was ineffective even at 100 mg/gk qd. In summary, ASP3026 has a broad safety margin and inhibitory activity at the gatekeeper mutation. Therefore, ASP3026 may still effective in EML4-ALK fusion positive NSCLC patients, that have relapsed to crizotinib.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2011 Nov 12-16; San Francisco, CA. Philadelphia (PA): AACR; Mol Cancer Ther 2011;10(11 Suppl):Abstract nr A227.
Abstract A229: BRAF inhibitors upregulate EGFR ligands: A molecular link to RAF inhibitor-induced cutaneous squamous cell carcinomas.
Authors: Ma Yan , Zhang Chao , Habets Gaston , Burton Elizabeth A. , Wong Bernice , Nguyen Hoa , Spevak Wayne , zhang Jiazhong , Cho Hanna , Wu Guoxian , Lin Jack L. , Ewing Todd , Zhang Ying , Shi Songyuan , Nespi Marika , Tsang Garson , Marimuthu Adhirai , Light Emily , Powell Ben , Shellooe Rafe , Tsai James , West Brian L. , Ibrahim Prabha N. , Hirth Peter , Bollag Gideon
Published: June 2012

Selective inhibitors of BRAF such as vemurafenib (PLX4032) and GSK2118436 show remarkable efficacy in melanoma patients with tumors harboring BRAF V600 mutations. However these compounds paradoxically activate the MAPK pathway in RAS-mutant cells and are associated clinically with appearance of skin tumors such as cutaneous squamous cell carcinomas (cuSCC), particularly of the keratoacanthoma subtype. Here we further investigated the molecular links between BRAF inhibitor treatment and skin neoplasm. In soft agar, BRAF inhibitors induced growth of HRAS-mutant cuSCC B9 cells via upregulation of several EGFR ligands. The EGFR inhibitor Tarceva antagonized this transforming effect. The “Paradox Breakers,” a class of BRAF inhibitors recently discovered at Plexxikon, did not activate the MAPK pathway in cells with RAS mutation or EGFR family kinase activation and failed to upregulate EGFR ligands or induce soft agar growth of B9 cells. Also when tested in vivo, subcutaneous B9-tumor growth was accelerated by a structural analog (PLX4720) of vemurafenib but not by an equally effective BRAF inhibitor of the Paradox Breaker class. Taken together, a novel mechanism responsible for BRAF inhibitor-induced cuSCC was uncovered. Our data suggest that combination treatment of EGFR inhibitors with BRAF inhibitors might prevent skin tumor growth and that Paradox Breakers represent a new generation of BRAF inhibitors that have fewer unwanted side effects and the potential for greater clinical efficacy.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2011 Nov 12-16; San Francisco, CA. Philadelphia (PA): AACR; Mol Cancer Ther 2011;10(11 Suppl):Abstract nr A229.
Abstract A241: Targeting FGFR4 for rhabdomyosarcoma therapy.
Authors: Cheuk Adam Tai Chi , Khan Javed
Published: June 2012

Rhabdomyosarcoma (RMS) is a soft tissue sarcoma in children. Despite advances in modern therapy, metastatic patients with this disease have a very poor clinical prognosis. FGFR4 is a tyrosine kinase receptor which plays a role in cell division, regulating cell growth and maturation. FGFR4 also involves in myogenesis and is a direct downstream target of PAX3-FOXO1A found in the majority of alveolar RMS subtype, and suggests its oncogenic role in RMS. Our and other's studies have shown that this gene is activated by amplification, over-expression and/or by mutation. Our previous data showed that activated FGFR4 promotes RMS tumor progression and inhibiting FGFR4 suppresses RMS tumor growth and metastasis. Ponatinib (Ariad, Cambridge, MA) is a multiple tyrosine kinase inhibitor that potently inhibits FGFR4 and is currently undergoing a pivotal phase 2 trial in adults with CML. Using a BaF3 TEL-FGFR4 model system, ponatinib was found to inhibit FGFR4 TK domain autophoshorylation and resulted in cell death. Five RMS cell lines that we have tested were all sensitive to ponatinib and the sensitivity was proportion to expression level of FGFR4. When treated with ponatinib, RMS cell line harboring the FGFR4 mutations K535 or E550, discovered by our group to be commonly mutated, were more sensitive to ponatinib compared to wild type as demonstrated by increase in active caspase 3/5 and in sub G1 population. Western blot confirmed that ponatinib inhibited autophosphorylation of FGFR4 K535 and E550 in a dose dependent manner. Furthermore, our pilot study also showed that the growth of subcutaneously injected RMS cells with the FGFR4 K535 mutants were suppressed after treating with ponatinib. Therefore our data suggest that ponatinib may be an effective therapy for patients with RMS and a clinical trial is warranted.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2011 Nov 12-16; San Francisco, CA. Philadelphia (PA): AACR; Mol Cancer Ther 2011;10(11 Suppl):Abstract nr A241.
Abstract A33: Pan erbB inhibition enhances lysosomal dysfunction-induced death in malignant peripheral nerve sheath tumor cells.
Authors: Kohli Latika , Carroll Steven L. , Roth Kevin A.
Published: June 2012

Malignant peripheral nerve sheath tumors (MPNSTs) are highly aggressive Schwann cell-derived sarcomas. The erbB family of membrane tyrosine kinases has been implicated in stimulating MPNST cell proliferation and invasion rendering it an attractive therapeutic target. However, tyrosine kinase inhibitors (TKIs) used as single agents are ineffective tumoricidal agents. Manipulating the autophagy lysosomal pathway in cells treated with cytostatic agents can promote apoptotic cell death in some settings. The goal of this study was to establish a mechanistic basis for formulating drug combinations to effectively trigger death in MPNST cells. We assessed the effects of the pan erbB inhibitor PD168393 on MPNST cell survival. PD168393 induced a cytostatic but not a cytotoxic response in MPNST cells which was accompanied by suppression of Akt and mTOR activation and increased autophagic activity. The effects of autophagy modulation on MPNST survival were then assessed by pharmacologic and genetic manipulations following the induction of chloroquine (CQ)-induced lysosomal stress. We observed that CQ-induced death is atleast in part apoptotic. In contrast, increased autophagy induction by inhibition of mTOR did not trigger cytotoxicity, possibly due to Akt activation. We thus hypothesized that dual targeting of mTOR and Akt by PD168393 would significantly increase cytotoxicity in cells exposed to lysosomal stress. We found that PD168393 and CQ in combination significantly increased cytotoxicity. We conclude that combinatorial therapies with erbB inhibitors and agents inducing lysosomal dysfunction may be an effective means of treating MPNSTs.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2011 Nov 12-16; San Francisco, CA. Philadelphia (PA): AACR; Mol Cancer Ther 2011;10(11 Suppl):Abstract nr A33.
Abstract A47: Circulating tumor cell (CTC) assay development for detection of phosphohistone H3 (pHH3) as a clinical pharmacodynamic (PD) marker for LY2523355, an Eg5 kinesin inhibitor.
Authors: Um Suzane L. , Yan S. Betty , Peek Victoria L. , Yan Lei , Ye Xiang S. , Westin Eric H.
Published: June 2012

Circulating tumor cells have been shown to be prognostic of survival in metastatic breast, colon, and prostate cancers. Additionally, CTCs are of interest because they may be representative of the phenotype/genotype of the primary and metastatic tumors, and may be a useful tool (i.e. patient stratification) for drug development. CTCs, as “liquid biopsies” are potentially useful as a PD marker as it allows easy repeat sampling before and after drug treatment. We describe the development of a CTC assay that measures the induction of pHH3 by LY2523355, a selective small molecule inhibitor of the human Eg5 kinesin. pHH3 is a biomarker of mitosis. In tumor xenograft mouse models, LY2523355 treatment was shown to reduce tumor volume with elevation of pHH3 in tumors. The CTC assay was developed using the FDA cleared Veridex/CellSearch™ instrument and reagents for enumeration of CTCs from blood. CellSearch defines CTCs as EpCam+/DAPI+/CK 8, 18, 19+/CD45−. For assay development, cells from tumor cell lines representing major solid tumor types were chosen, cultured, treated with LY2523355, or with various standard-of-care chemotherapeutics, and spiked into whole blood drawn into CellSave™ (preservative+EDTA). For initial assay development, mouse whole blood was used and results reproduced subsequently with human whole blood from healthy subjects. The spiked tumor cells in blood samples were recovered using the CellSearch Mouse/Rat CTC kit (for mouse blood) or human CXC kit (for human blood), supplemented with the R-PE conjugated anti-pHH3 antibody. pHH3 in the recovered tumor cells was detected in the open/fourth channel on the CellSearch instrument. About 1–4% of all cultured tumor cells were positive for pHH3 without drug treatment. Significant induction of pHH3 (30–50% cells) in sensitive tumor cell lines was observed with 24 hour treatment with only drugs interfering with mitosis (paclitaxel, taxotere, and LY2523355). The magnitude of the induction of pHH3 in the cells after treatment was dose and cell-line dependent. A dose response of pHH3 induction was observed with 0.5nM-25nM of LY2523355 with several cultured tumor cell lines (Colo205, HCT116, H441, SKBR3, MDA-MB-468), spiked into blood, and assayed using CellSearch. The concentrations of the dose response are similar to the drug exposure levels of that of preclinical tumor xenograft studies. LY2523355 is currently in early phase clinical development, and monitoring CTCs with pHH3 expression post-treatment may be a useful PD marker.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2011 Nov 12-16; San Francisco, CA. Philadelphia (PA): AACR; Mol Cancer Ther 2011;10(11 Suppl):Abstract nr A47.
Abstract A58: Epigenetic regulation of CpG promoters by NF-kB pathway in invasive pancreatic cancer cells.
Authors: Sun Lei , Mathews Lesley , Cabarcas Stephanie , Zhang Xiaohu , Farrar William
Published: June 2012

Pancreatic cancer is one of the most common causes of cancer death internationally. The diagnosis of early-stage pancreatic cancer often has a poor prognosis and the survival rate is quite low once it becomes advanced or metastatic. Epigenetic modifications such as DNA methylation play a significant role during both normal human development and cancer progression. We sought to investigate which genes are epigenetically regulated in the invasive population of pancreatic cancer cells. We conducted epigenetic arrays in both PANC1 and HPAC pancreatic cancer cell lines and compared the global DNA methylation status of CpG promoters in invasive cells to their non-invasive counterparts. The differentially methylated genes were applied into Ingenuity pathway analysis and our results showed that the NF-kB pathway is one of the top activated pathways in invasive cells. In line with this, we determined that upon treatment with NF-kB pathway inhibitors, the invasive and migratory ability of total cells are significantly disrupted. Moreover, the SRY-box transcription factor SOX9, which is demethylated in invasive cells, is shown to play a crucial role in invasion of both cell lines. In addition, we found a potential NF-kB binding site located in the SOX9 promoter in Genomatix database. Interestingly, the NF-kB subunit p65 positively regulates SOX9 expression by binding to its promoter directly, which is enhanced by treatment of demethylation agents. Thus, our work establishes a link between the classical NF-kB signaling transduction pathway and pancreatic cancer cell invasion. We believe our data can result in the identification of novel signals and molecules at an epigenetic level that can potentially be targeted in pharmaceutical investigations and clinical trials.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2011 Nov 12-16; San Francisco, CA. Philadelphia (PA): AACR; Mol Cancer Ther 2011;10(11 Suppl):Abstract nr A58.
Abstract A64: Adenovirus-mediated NK4 gene therapy for malignant mesothelioma.
Authors: Deng Xu-Bin , Xiao Li , Jin Fang , Testa Joseph , Xiao Guang-Hui
Published: June 2012

Malignant mesothelioma (MM) is a highly invasive and chemoresistant malignancy induced by asbestos fibers. Hepatocyte growth factor (HGF) and its receptor Met play a critical role in the pathogenesis of MM, and targeting HGF/Met signaling could be therapeutically important. NK4, a HGF antagonist and angiogenesis inhibitor, consists of the N-terminal hairpin domain and four kringle domains of the -chain of HGF. The therapeutic potential of NK4 has been demonstrated in several types of tumors. However the mechanisms by which NK4 inhibits tumor growth have not been well elucidated. In this study, we show that the NK4 adenovirus potently inhibits cell viability, invasiveness, migration, and spreading of human MM cells in vitro. Significantly, we demonstrated for the first time that NK4 reduced expression levels of stem cell markers as assessed by western blot analysis and inhibited self-renewal of MM stem cells as measured by spheroid formation assay. Furthermore, NK4 adenovirus had strong antitumor and anti-angiogenesis effects in two different mouse models of MM. These findings suggest that NK4 holds promise as a therapeutic agent for patients with MM.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2011 Nov 12-16; San Francisco, CA. Philadelphia (PA): AACR; Mol Cancer Ther 2011;10(11 Suppl):Abstract nr A64.
Abstract A71: Cdk2, Mad2, and the tetraploidy checkpoint in paclitaxel-induced endoreduplication.
Authors: Jahn Stephan , Corsino Patrick , Law Mary , Davis Brad , Law Brian
Published: June 2012

The classic chemotherapeutic, paclitaxel, causes endoreduplication in cells, but the mechanism and cellular characteristics that promote this genome doubling are poorly understood. In studying the chromosomal instability of tumor cell lines from mice with mammary expression of a constitutively active Cyclin D1-Cdk2 fusion protein, we noticed an increased rate of this paclitaxel induced endoreduplication. Further studies have shown that this effect is specifically due to the kinase activity of Cdk2 and that increased Cdk2 activity causes of upregulation of the mitotic checkpoint protein, Mad2. While increased Mad2 expression alone has previously been shown to cause mitotic defects and genome doubling, it does not appear to be the culprit in this situation. We instead found that normalization of Mad2 levels through short hairpin RNA-mediated knockdown further increased the rate of endoreduplication in the presence of paclitaxel. It was seen that while exposure to the spindle poison further elevated Mad2 levels, long-term treatment led to an overall decrease in protein expression. This presumably allows cells to escape mitotic arrest and enter G1 phase, potentially triggering the somewhat controversial p53-mediated tetraploidy checkpoint. Indeed, stable knock-down of p53 cooperates with increased Cdk2 activity to create a very high rate of endoreduplication. These findings raise intriguing questions about the consequences of using one of the world's most widely used chemotherapeutic agents in patients with increased Cdk2 activity. Future studies will investigate whether this increased rate of endoreduplication worsens treatment outcome by eliciting chromosomal instability or improves it by generating cells that are unviable in the long-term.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2011 Nov 12-16; San Francisco, CA. Philadelphia (PA): AACR; Mol Cancer Ther 2011;10(11 Suppl):Abstract nr A71.
Abstract A84: Lack of efficacy of the anti-diabetic drug metformin in the ER+ methylnitrosourea (MNU)-induced and the ER− MMTV-Neu/p53KO models of mammary cancer.
Authors: Grubbs Clinton J. , Clapper Margie , Bode Ann , Steele Vernon , Lubet Ronald
Published: June 2012

Metformin, an anti-diabetic drug, activates AMP-activated protein kinase (AMPK), and has generated a great deal of interest as a potential preventive agent for a variety of cancers, including breast. This interest is based both on epidemiologic studies showing that diabetics treated with metformin have a lower incidence of a variety of cancers, and on mechanistic considerations arguing that activation of AMPK is likely to be relevant to cancer treatment and prevention. We examined the preventive efficacy of metformin in ER+ and ER− rodent mammary cancer models. Treatment of Sprague-Dawley female rats at 50 days of age with a single dose of MNU (75 mg/kg BW) resulted in the development of multiple ER+ mammary cancers beginning approximately 7 weeks after MNU treatment. This model has been highly responsive to a wide variety of agents that affect ER+ tumors in humans (SERMs, aromatase inhibitors, pregnancy, ovariectomy). Metformin was administered by gavage (7×/week) at either 150 or 50 mg/kg BW/day beginning 7 days after MNU dosing, and continuing for the duration of the study. Metformin failed to decrease mammary tumor incidence and, in fact, increased tumor multiplicity in this model by approximately 35%. In addition, we are evaluating the ability of metformin to inhibit mammary cancer in MMTV-Neu/p53KO mice (which spontaneously develop ER− cancers). In this study, metformin was administered in the diet at a dose level of 1500 mg/kg diet. Initial supplementation of the diet with this agent began when the mice were 60 days of age, and will continue for 10 months. This study similarly has shown no preventive efficacy of metformin (av. tumors/mice: controls, 2.1; metformin, 2.5). Thus, these initial studies fail to observe any chemopreventive efficacy of metformin in two commonly employed models of ER+ and ER− mammary cancers in rodents.

Supported by NCI contract number HHSN261200433001C.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2011 Nov 12-16; San Francisco, CA. Philadelphia (PA): AACR; Mol Cancer Ther 2011;10(11 Suppl):Abstract nr A84.
Abstract A92: A phase 1 safety and pharmacokinetic study of navitoclax in combination with docetaxel in patients with solid tumors.
Authors: Eskens Ferry ALM , Gutierrez Martin , Cosgrove David , Puglisi Martina , van Doorn Leni , Blanco Montserrat , de Jonge Maja JA , Moran Kirsty , Walther Axel , Yang Jianning , Busman Todd A. , Franklin Catherine A. , Mabry Mack H. , Humerickhouse Rod A. , Molife Lulama Rhoda
Published: June 2012

Background: Navitoclax (N; ABT-263) is a first-in-class orally available Bcl-2 protein inhibitor that in vitro and in vivo potentiates docetaxel (D) activity across a variety of solid tumor types. This ongoing phase I study evaluates the maximum tolerated dose (MTD) and safety and pharmacokinetic (PK) profile of N plus D.

Methods: Patients (pts) with advanced solid tumors, adequate organ function and ECOG PS ≤1 were eligible. Pts were treated with (a) N 150 mg or 200 mg PO, QD on days (d) 1–3 or d1–5 q21 plus D 75 mg/m2 IV on d1 q21; or (b) N 150 mg PO, QD on d1–3, d8–10, and d15–17 q28 plus D 30 mg/m2 IV given on d1, 8, and 15 q28. To compare the PK of either agent alone, N was given on d3–5 or d3–7 only in cycle 2 of q21. PK samples were collected for N and D in cycles 1 and 2. Treatment-emergent adverse events (TAEs) were graded by NCI CTCAE V3.0.

Results: Of 37 pts (M/F, 24/13) enrolled, data on 31 pts are available for safety, 33 pts for tumor response, and 13 pts for PK analysis. Pts (median age, 59 y; range, 30–83 y) were treated at 3 dose levels of N: 150 mg and 200 mg on d1–5 q21; 200 mg on d1–3 q21; and 150 mg on d1–3, d8–10, and d15–17 q28. Dose-limiting toxicities (DLTs) were grade (gr) 3 febrile neutropenia, and gr 4 thrombocytopenia (TCP) at N 200 mg d1–5 plus D 75 mg/m2 q21; gr 3/4 febrile neutropenia, gr 4 neutropenia, and gr 3 fatigue at N 200 mg d1–3 plus D 75 mg/m2 q21; gr 3 febrile neutropenia, gr 4 TCP, and death at N 150 mg d1–5 plus D 75 mg/m2 q21. The MTD of N with D at 75 mg/m2 q21 was 150 mg on d1–5. Other gr 3/4 TAEs (≥20%) were neutropenia (55%), leukopenia (32%), febrile neutropenia (29%), TCP (29%), and fatigue (13%); frequently occurring TAEs (≥20%) were fatigue (55%), TCP (45%), alopecia (42%), nausea (42%), anemia (36%), constipation (32%), decreased appetite (32%), diarrhea (32%), vomiting (32%), and dyspnoea (26%). Best tumor responses were 3 confirmed partial responses (PR), 2 currently unconfirmed PR, 8 stable disease (SD), 13 progressive disease, and 7 pts had incomplete data. Based on limited data, there was no significant PK interaction between N and D (Table).

Conclusions: Navitoclax may be administered safely with D in 2 schedules; 150 mg with D 75 mg/m2 q21 and with D 30 mg/m2 q28. Both combinations were tolerable with no significant PK interactions in the D 75 mg/m2 q21 schedule. Antitumor activity was observed. Exploration of N 200 mg with weekly D is ongoing.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2011 Nov 12-16; San Francisco, CA. Philadelphia (PA): AACR; Mol Cancer Ther 2011;10(11 Suppl):Abstract nr A92.
Abstract B1: Antitumor activity of TSU-68 in PDGF-BB overexpressing U-87MG xenograft model: contribution of PDGFR blocking action.
Authors: Hosoi Fumihito , Yokoi Hiromi , Nameki Daisuke , Hayashi Hiroaki , Ito Kenjiro , Masuko Norio , Minamiguchi Kazuhisa , Matsuo Ken-ichi , Utsugi Teruhiro
Published: June 2012

PDGFR is an important target for novel anticancer therapeutics because it is overexpressed in a wide variety of malignancies. TSU-68, a new drug under clinical study that inhibits an angiogenic receptor tyrosine kinase KDR, which play a crucial role in tumor-induced vascularization, inhibits angiogenesis and the growth of human tumor xenografts in vivo. This compound is also a potent inhibitor of PDGFRα and PDGFRβ kinases. In this study, PDGF-BB overexpressing human tumor model was used to characterize the in vivo activity of TSU-68 as a PDGFR blocking agent.

In vivo xenograft mice study, TSU-68 treatment (once daily p.o. dosing for 28 days) exhibited potent antitumor activity in PDGF-BB overexpressing U-87MG (U-87MG/PDGF-9) xenograft (T/C 28.2%) in comparison to parental U-87MG xenograft (T/C 69.7%). Expression level of VEGF of U-87MG/PDGF-9 cells was similar to that of parental U-87MG cells. PDGF-BB was only detected in plasma of mice bearing U-87MG/PDGF-9 xenograft. To identify the action of TSU-68 on U-87MG/PDGF-9 tumor, in vitro cell proliferation assay, ex vivo study, and immunohistological examination of xenografts were carried out. TSU-68 inhibited cell proliferation of U-87MG cells induced by PDGF-BB but not by FBS. In U-87MG/PDGF-9 xenograft tumors, PDGFR was highly phosphorylated and a single oral dose of TSU-68 (200 mg/kg) inhibited phosphorylation of PDGFR in the tumors. Immunohistochemical analyses revealed reduced Ki-67 staining in the tumors from TSU-68-treated mice relative to the vehicle control. The Ki-67 labeling index, calculated as the percentage of positive staining cells of total nucleated cells in a field was 47.0 ± 8.5 vs. 31.8 ± 4.5 (p<0.01) for vehicle control and TSU-68-treated U-87MG/PDGF-9 tumor samples, respectively. And, the microvessels in U-87MG/PDGF-9 xenografts were quantified by immunostaining of CD31. A significant decrease in microvessel area (MVA) was detected in the tumors from TSU-68-treated mice compared with vehicle control (13.5 ± 3.1 vs. 4.6 ± 1.0, p<0.01). Similar results were also obtained in microvessel density (MVD). These data support that the in vivo antitumor effect of TSU-68 on PDGF-BB overexpressing U-87MG is associated with the inhibition of PDGF/PDGFR axis of tumor and neoangiogenesis. TSU-68 has some programs currently under clinical evaluation for the therapy of cancer. PDGF/PDGFR axis is one of the possible biomarkers for stratification of patients in future clinical trials.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2011 Nov 12-16; San Francisco, CA. Philadelphia (PA): AACR; Mol Cancer Ther 2011;10(11 Suppl):Abstract nr B1.