bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract A155: The Rac and PAK inhibitor EHop-016 inhibits mammary tumor growth and metastasis in a nude mouse model.
Authors: Castillo-Pichardo Linette , Humphries-Bickley Tessa , Hernandez Eliud , de la Parra Columba , Cubano Luis , Vlaar Cornelis , Dharmawardhane Flanagan Surangani F.
Published: August 2014

The Rho GTPase Rac is a central regulator of cancer cell migration/invasion that has been implicated with cancer metastasis. Therefore, we designed and developed small molecule compounds that specifically target Rac in metastatic cancer cells. We recently reported the characterization of EHop-016 as a Rac inhibitor in metastatic cancer cells, where EHop-016 was shown to inhibit Rac activity with an IC50 of 1 μM. At higher concentrations (>10 μM) EHop-016 reduced cell viability and inhibited the related Rho GTPase Cdc42, but not Rho. EHop-016 decreased the activation of Rac by the oncogenic guanine nucleotide exchange factor Vav, the activity of the Rac effector p21-activated kinase (PAK), and the extension of actin cytoskeletal structures and migration of metastatic cancer cells. Next, we determined the efficacy of EHop-016 in vivo, using a mouse model of experimental metastasis. Green fluorescent protein (GFP) tagged MDA-MB-435 human metastatic cancer cells were inoculated at the mammary fat pad of nude mice and treated with 0, 5, 10, 25, or 40 mg/kg body weight (BW) EHop-016 3X a week for ∼8 weeks. Mammary tumor growth and metastases in lungs, spleens, kidneys, livers, hearts, and femurs were quantified by fluorescence image analysis. At concentrations >10 mg/kg BW, EHop-016 significantly inhibited mammary tumor growth and metastasis to distant organs. EHop-016 had no effect on mouse weight or their gross phenotype, indicating that EHop-016 did not exert toxic effects in athymic nude mice. This data demonstrate that EHop-016 and derivatives hold promise for further development as targeted anti-cancer therapeutics.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):A155.

Citation Format: Linette Castillo-Pichardo, Tessa Humphries-Bickley, Eliud Hernandez, Columba de la Parra, Luis Cubano, Cornelis Vlaar, Surangani F. Dharmawardhane Flanagan. The Rac and PAK inhibitor EHop-016 inhibits mammary tumor growth and metastasis in a nude mouse model. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr A155.
Abstract A157: Metastatic PDX modeling displays correlation between CTC and metastatic potential, both inhibited by chemotherapy.
Authors: Jiang Jiahua , Wang Daisy D. , Yang Mengmeng , Chen Dawei , Guo Sheng , Cai Jie , Li Linda , Wery Jean-Pierre , Lin Peter Ping , Li Henry
Published: August 2014

Gastric carcinoma is a common cancer of high mortality and is particularly prevalent in East Asia. There are only a few treatment options: surgery, chemotherapy, as well as Herceptin® for a small subset of patients with erbb2 amplification. Metastasis usually renders surgery ineffective. Drug therapy becomes only meaningful option. One of the keys to a successful search for effective treatment is development of experimental model that truly mimics patient conditions. Patient derived xenograft (PDX or HuPrime®) is believed to be among the best mimicking human diseases (1). Recently, we have established a cohort of ∼70 gastric cancers from Asian and Caucasian patients. This report describes that two of them (GA0046, GA0087), while established as subcutaneous xenografts, were confirmed to metastasize to lung at high frequency (100% for GA0087). GA0087 is a neuroendocrine cancer of gastric origin. Its high metastasis potential, as measured by counting the colony nudules in lung of subcutaneous tumor bearing mice, suggests that it would be a useful experimental model for studying cancer metastasis and exploring inhibitory agents. The observed metastasis is particularly significant since metastasis is rarely occurin subcutaneous xenograft. Circulating tumor cells, or CTCs, have been identified in the blood of some cancer patients and believed to be responsible for cancer metastasis (2, 3). We recently developed a new method, based on subtraction enrichment combined with immunofluorescence staining (anti-human cytokeratin 18 and CD45 monoclonal antibodies) and FISH (iFISH), for effective identification and enumeration of CTCs enriched from bloods of patients (4). In this study, we investigated the presence of CTCs in GA0087 metastatic PDX and their potential correlation to metastastic potential. As a result, we, for the first time, detected CTCs in PDX (GA0087), with a range of 1-61 CTCs per 200μL mouse blood. Our preliminary observation seems to also indicate that the CTC frequency is correlated to the numbers of metastasis nodules in lung. Furthermore, a chemotherapy agent can inhibited both CTC and metastasis. Our data seem to confirm the proposed correlation of metastasis and CTC in this first experimental metastasis/CTC PDX model.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):A157.

Citation Format: Jiahua Jiang, Daisy D. Wang, Mengmeng Yang, Dawei Chen, Sheng Guo, Jie Cai, Linda Li, Jean-Pierre Wery, Peter Ping Lin, Henry Li. Metastatic PDX modeling displays correlation between CTC and metastatic potential, both inhibited by chemotherapy. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr A157.
Abstract A178: Epigallocatechin-3-gallate (EGCG) induces catalase-sensitive cell growth inhibition and AKT activation in Burkitt lymphoma cells.
Authors: Van Doorn Carl-Christian , Domina Aaron M.
Published: August 2014

Burkitt lymphoma is an aggressive non-Hodgkin's B cell lymphoma. It is typically treated with high intensity chemotherapy, which is associated with toxicities. Therefore, it is important to develop novel treatments for this disease. Studies have found that the green tea-derived compound, epigallocatechin-3-gallate (EGCG), may be effective in treating Burkitt lymphoma (Nakazato T. et. al., 2005 and Noda C. et. al., 2007). Another study showed that the phosphatidylinositide 3-kinase (PI3K)/AKT pathway is important for Burkitt lymphoma proliferation and survival (Schmizt R. et. al., 2012). Therefore the purpose of this current study is to investigate the connection between EGCG and the PI3K/AKT pathway in Burkitt lymphoma cells. To begin, it was evaluated whether EGCG would induce dose-dependent, catalase-sensitive growth inhibition of the sporadic Burkitt lymphoma cell lines, BL41-3, DG75, and Ramos. These cells were treated with EGCG at varying doses and also in the presence or absence of catalase followed by MTT analysis. EGCG induced a dose-dependent growth inhibition of all three Burkitt lymphoma cell lines and co-treatment with catalase prevented this effect. To determine the effects of EGCG on the PI3K/AKT pathway, BL41-3, DG75, and Ramos, were treated with 0, 20, 40, or 80 μM EGCG followed by Western analysis for phosphorylated AKT and total AKT. The results indicated that AKT phosphorylation is increased in all three cell lines following EGCG treatment. Lastly, it was investigated how inhibition of PI3K during EGCG treatment impacts the anti-proliferative effects seen with EGCG alone. To test this, BL41-3, DG75, and Ramos cells were treated with EGCG and an inhibitor of PI3K, LY294002, followed by MTT analysis. EGCG and LY294002 inhibited Burkitt lymphoma cell growth, although the degree of inhibition and the effect of combination treatment varied between the three cell lines. In conclusion, EGCG induced AKT phosphorylation along with a catalase-sensitive growth inhibition and the addition of a PI3K inhibitor had an additive growth inhibitory effect with EGCG. These results provide novel insight into the use of EGCG for the treatment of sporadic Burkitt lymphomas.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):A178.

Citation Format: Carl-Christian Van Doorn, Aaron M. Domina. Epigallocatechin-3-gallate (EGCG) induces catalase-sensitive cell growth inhibition and AKT activation in Burkitt lymphoma cells. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr A178.
Abstract A180: Selective inhibition of K-Ras G12C through allosteric control of GTP affinity and effector interactions.
Authors: Peters Ulf , Ostrem Jonathan M. , Sos Martin L. , Wells James A. , Shokat Kevan M.
Published: August 2014

Somatic mutations in the small GTPase K-Ras are the most common activating lesions found in human cancer, and are generally associated with poor response to standard therapies. Efforts to directly target this oncogene have faced difficulties due to its picomolar affinity for GTP/GDP and the absence of known allosteric regulatory sites. Oncogenic mutations result in functional activation of Ras family proteins by impairing GTP hydrolysis. With diminished regulation by GTPase activity, the nucleotide state of Ras becomes more dependent upon relative nucleotide affinity and concentration. This gives GTP an advantage over GDP and increases the proportion of active GTP-bound Ras. Here, we report the development of small molecules that irreversibly bind to a common oncogenic mutant, K-Ras G12C. These compounds rely on the mutant cysteine for binding and therefore do not affect the wild type protein (WT). Crystallographic studies reveal the formation of a new pocket that is not apparent in previous structures of Ras, beneath the effector binding switch-II region. Binding of these inhibitors to K-Ras G12C disrupts both switch-I and switch-II, subverting the native nucleotide preference to favor GDP over GTP and impairing binding to Raf. Our data provide structure-based validation of a novel allosteric regulatory site on Ras that is targetable in a mutant specific manner.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):A180.

Citation Format: Ulf Peters, Jonathan M. Ostrem, Martin L. Sos, James A. Wells, Kevan M. Shokat. Selective inhibition of K-Ras G12C through allosteric control of GTP affinity and effector interactions. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr A180.
Abstract A189: The combination of NPV-LDE-225 (Erismodegib) and BEZ-235 is superior to single agent alone in inhibiting glioblastoma initiating cell growth in vitro and in vivo.
Authors: Sharma Narinder , Kumar Dhruv , Ma Yiming , Yu Wei , Shankar Sharmila , Srivastava Rakesh K.
Published: August 2014

Glioblastoma multiforme (GBM) is the most common form of primary brain tumor and often characterized by poor survival. Glioblastoma initiating cells (GICs) regulate self-renewal, differentiation and tumor initiation properties, and are involved in tumor growth, recurrence, and resistance to conventional treatments. The objectives of this study were to examine the molecular mechanisms by which inhibition of PI3K/mTOR and Sonic hedgehog (Shh) pathways cooperate together to suppress GIC growth in vitro and in vivo. PI3K/mTOR and Shh pathways were inhibited by NPV-LDE-225 (Erismodegib) and BEZ-235, respectively. Cell viability and apoptosis were measured by XTT and annexin/IV-PI assays, respectively. Gli transcriptional activity was measured by luciferase reporter assay. Gene and protein expressions were measured by qRT-PCR and Western blot analyses, respectively. NPV-LDE-225 inhibited Gli1 and Gli2 expression and transcription activity. BEZ-235 inhibited the phosphorylation of PI3K and mTOR. NPV-LDE-225 and BEZ-235 acted in a synergistic manner to inhibit cell viability, neurosphere formation, and Gli transcriptional activity, and to induce apoptosis by activation of caspase-3 and cleavage of PARP. Furthermore, NPV-LDE-225 and BEZ-235 cooperates together to inhibit pluripotency maintaining factors (Nanog, Oct4, Sox-2, and cMyc) and epithelial-mesenchymal transition. Finally, the interactive effects of NPV-LDE-225 and BEZ-235 on GIC tumor growth in nude mice was higher than single agent alone. Our data suggest that the combined inhibition of PI3K/mTOR and smoothened can be used for the treatment of GBM by targeting GICs.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):A189.

Citation Format: Narinder Sharma, Dhruv Kumar, Yiming Ma, Wei Yu, Sharmila Shankar, Rakesh K. Srivastava. The combination of NPV-LDE-225 (Erismodegib) and BEZ-235 is superior to single agent alone in inhibiting glioblastoma initiating cell growth in vitro and in vivo. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr A189.
Abstract A200: Toward quantitative PI3K pathway PD analysis in clinical samples using an automated capillary electrophoresis-immunoassay platform.
Authors: Mccoon Patricia E. , Pablo Lourdes , McEachern Kristen , Foster Emily , Womack Chris , Castriotta Lillian , Brown Jeff , Barrett Carl
Published: August 2014

Here we report results of an independent evaluation of an automated capillary electrophoresis-immunoassay system for its utility in generating quantitative and reproducible pharmacodynamic (PD) biomarker data for the PI3K pathway using clinical specimens. Quantitative measurement of PD biomarkers associated with drug -target engagement in tumor tissue is an increasingly important part of evaluating new cancer therapies in early clinical trials. PD data are currently being used along with safety, pharmacokinetics, and efficacy data to make more informed clinical decisions regarding likelihood of success and progression of drugs into Phase II testing. Despite this increased focus, there are still very few assay platforms that support automated, reproducible and quantitative methods amenable to the small tumor biopsies available for these analyses. The Peggy™ (ProteinSimple) platform provides automated separation of proteins by size or charge and quantitation of analytes over a broad dynamic range from tissue samples using as little as 40 ng protein. Accompanied by the ability to process 96-samples in a single run, this platform is amenable to both pre-clinical and clinical PD determination.

Our initial studies focused on evaluating the feasibility of developing a set of robust, quantitative PD biomarker assays that could be used systematically across our oncology portfolio to monitor the PI3K pathway. Here we present results for a panel of biomarkers associated with the PI3K pathway using cell lines and tumor xenografts in which we measured responses to drug treatments using AKT and mTOR inhibitors. Further, in a set of prospectively collected breast cancer core needle biopsies, we were able to detect baseline levels of these biomarkers. Taken together, these data suggest that this platform will be useful in quantitatively measuring changes in multiple PD biomarkers in a single tumor biopsy. Going forward, we propose to utilize this approach alone or in tandem with other immunoassay formats, such as immunohistochemistry, to provide greater insight into tumor biology and the effects of drug treatment following PI3K -AKT inhibition in the clinic to help inform important clinical decisions.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):A200.

Citation Format: Patricia E. Mccoon, Lourdes Pablo, Kristen McEachern, Emily Foster, Chris Womack, Lillian Castriotta, Jeff Brown, Carl Barrett. Toward quantitative PI3K pathway PD analysis in clinical samples using an automated capillary electrophoresis-immunoassay platform. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr A200.
Abstract A206: 2D cell culture can approximate 3D behavior: Applications for screening individual agents and drug combinations.
Authors: Ivanov Igor , Taherzadeh Danial , Nunziante Maximilian
Published: August 2014

Developed and serving over the last 30 years as an indispensible screening tool, 2D in vitro screening has been criticized for poor predictive powers in clinical settings. New tools are under development, e.g. 3D spheroids or “hanging-drops," to overcome these limitations. However, new tools have other restrictions. For example, costs and application for multiple cell lines: model 2D cell lines may not grow as spheroids.

We developed a set of analytical and computational models to approximate cell growth upon drug treatment. We could show that for a common 2D cell culture the effect of drug treatment, and therefore interpretation of the results, depends on several factors: seeding cell density, treatment time, cell doubling time, and compound mode of action.

To address such limitations we further developed a modified 2D culture. In contrast to a common experimental set-up of low cell density to allow exponential cell growth and short 48-96 hours treatment times, we allowed cells to grow to higher ∼80% confluence densities. Treatment was monitored not as an end-point assay, but in a kinetic mode (every 96 hours) over a period of 4 weeks.

We treated 82 cell lines using a set of standard anticancer agents, including 5-FU, paclitaxel, sunitinib, etoposide, lapatinib and eroltinib. Interestingly, some cell lines showing significant responses in classical 2D models, appear to be non-responsive to the drug in dense 2D (D2D) models. This was very obvious for some targeted agents, e.g. EGFRi, probably due to down-regulation of the drug targets in cell lines growing as D2D. In addition, we have applied the same principle to drug combination studies in all 82 cell lines.

These results indicate that D2D cell models can approximate cell growth observed in 3D cell cultures by enhancing cell-cell interactions. D2D screening can be performed in hundreds of cell lines (at least 82 different cancer cell lines, as shown here). In contrast to 3D models and end-point detection, D2D also records the drug response kinetics, and can be easily applied for drug combinations. This is especially relevant for slow acting agents, e.g. cytostatic agents.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):A206.

Citation Format: Igor Ivanov, Danial Taherzadeh, Maximilian Nunziante. 2D cell culture can approximate 3D behavior: Applications for screening individual agents and drug combinations. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr A206.
Abstract A209: Predicting genetic drivers of MEK dependency with gene expression.
Authors: Dry Jonathan R. , Hodgson Darren , Brant Roz , Liptrot Tom , Harrington Elizabeth , Barrett Carl , Smith Paul D.
Published: August 2014

Inhibition of the RAS-RAF-MEK axis holds significant promise for targeted cancer therapy, highlighted by the recent clinical approval of BRAF (vemurafenib) and MEK (trametinib) inhibitors, and ongoing late-stage clinical trials for several other MEK inhibitors. All genetic aberrations resulting in pathway activation and dependency through which optimum patient populations may be selected are as yet not fully determined. Previously we published an 18-gene mRNA expression signature reproducibly predictive of MEK pathway output and response to MEK inhibition with selumetinib. Here we demonstrate that a 6-gene sub-signature shows enhanced reproducibility in cell lines, primary tumor explant in vivo models and fresh/fixed tissue samples, crossing tumor type and gene expression platforms. In published next-generation sequencing datasets we assessed pathway-linked genetic aberrations for their impact on MEK signature output. We show the potential for this signature to dissect MEK dependency amongst RAS mutant tumors. Furthermore we identify a number of genetic aberrations outside of BRAF and KRAS driving high MEK signature expression, including a synthetic lethal-like profile with NF1 deletion. The signature provides a robust and dynamic marker of MEK output applicable to clinical samples, and highlights a number of genetic opportunities to expand the clinical scope for MEK inhibitor based therapies.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):A209.

Citation Format: Jonathan R. Dry, Darren Hodgson, Roz Brant, Tom Liptrot, Elizabeth Harrington, Carl Barrett, Paul D. Smith. Predicting genetic drivers of MEK dependency with gene expression. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr A209.
Abstract A21: Autophagy: A potential target for colorectal cancer therapeutics.
Authors: Amin Amr , Bajbouj Khuloud , Koch Adrian , Gandesiri M. , Schneider-Stock Regine
Published: August 2014

Colorectal cancer is among the leading causes of death worldwide. Here, we investigate the molecular mechanism of crocin-induced apoptosis in colorectal cancer cells. Crocin was shown here to inhibit proliferation of both HCT wildtype and HCT p53-/- cell lines at a concentration of 10 mM. Flow cytometric analysis of cell cycle distribution revealed that there was an accumulation of HCT wildtype cells in G1 compared to the control after 24 and 48 hours of crocin treatment, respectively. However, crocin induced only mild G2 arrest in HCT p53-/- after 24 hours. Crocin induced apoptosis in both cell lines in a time dependent manner. Nevertheless, p53 deficient cells were not able to repair the damage induced by crocin. Crocin induced inefficient autophagy in HCT p53-/- cells where crocin induced the formation of LC3-II which was combined by a decrease in the protein levels of beclin 1 and Atg7 and no clear p62 degradation. Autophagosome formation was not detected in HCT p53-/- after crocin treatment predicting a nonfunctional autophagosome formation. There was a significant increase of p62 after treating the cells with Bafilomycin A1 (Baf) and crocin compared to crocin exposure alone, indicating an effective autophagic flux. Annexin V staining showed that Baf-pretreatment enhanced the induction of apoptosis in HCT wildtype cells. Baf-exposed-HCT p53-/- cells did not show any enhancement of apoptosis induction despite an increase in the DNA damage sensor accumulation, γH2AX indicating that crocin induced an autophagy-independent classical programmed cell death.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):A21.

Citation Format: Amr Amin, Khuloud Bajbouj, Adrian Koch, M. Gandesiri, Regine Schneider-Stock. Autophagy: A potential target for colorectal cancer therapeutics. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr A21.
Abstract A211: Multiethnic screening for irinotecan sensitivity in FFPE tissue from colorectal cancer patients.
Authors: Hsiang Jack , El-Khoueiry Rita , Lenz Heinz-Josef , Astrow Stephanie H. , Larson Garrett P.
Published: August 2014

The selection of chemotherapies is guided by the analysis of molecular targets in solid tumors for well-known somatic mutations identified in microdissected FFPE tissue. Combining a molecular targeting panel with select pharmacogenomic targets provides additional clinical information useful in customized patient management. We have developed a combined pharmacogenomic/molecular target approach using FFPE tissue from colon cancer patients. Our test, based on FDA guidance for Irinotecan administration to metastatic colorectal cancer (CRC) patients, is a recommended prescreening assay for UGT1A1 [TA] promoter variations to mimimize neutropenia. Meta-analysis of Irinotecan treated CRC patients has demonstrated an association between the [TA]7 allele (UGT1A1*28) and elevated levels of neutropenia in both homozygous and heterozygous carriers suggesting lowered dosing regimens (Liu, et al Pharmacogenomics J, 2013). Additional alleles, while uncommon in Caucasians, contribute to decreased levels of UGT1A1 enzymatic activity, and are restricted to genetic subgroups. Collectively these alleles influence the pharmacodynamic t1/2 of Irinotecan but are often not widely screened. Thus, a screening palate encompassing multiple ethnic-specific variants provides improved predictive information in a cosmopolitan population of cancer patients. As these polymorphisms are germline changes, UGT1A1 genotypes can be derived from either traditional whole blood assessment or more conveniently from FFPE surgical tissue at the time of diagnosis. We have screened paired blood/tumor samples from CRC patients to examine potential loss of heterozygosity in tumor specimens at this locus. In parallel, we screened microdissected tumor and adjacent normal tissue from FFPE samples to verify the potential of using tumor specimens as a routine alternative to blood. The use of FFPE tissue from CRC patients as part of a molecular work-up can provide genotypes for multiple UGT1A1 alleles of reduced activity (including *28), and may be better at predicting neutropenia in distinct Caucasian, Asian or other genetically distinct patient populations. The development of FFPE-based tests for pharmacogenomic tests such as UGT1A1 premised on genetic ancestry provides actionable information that can be used to maximize patient responses.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):A211.

Citation Format: Jack Hsiang, Rita El-Khoueiry, Heinz-Josef Lenz, Stephanie H. Astrow, Garrett P. Larson. Multiethnic screening for irinotecan sensitivity in FFPE tissue from colorectal cancer patients. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr A211.
Abstract A226: Identification of new synergistic compounds for the treatment of NOTCH-driven T-ALL.
Authors: Sanchez Martin Marta , Ambesi Alberto , Herranz Daniel , Ferrando Adolfo
Published: August 2014

T cell acute lymphoblastic leukemia (T-ALL) is an aggressive hematologic malignancy that accounts for 15% of childhood and 25% of adult ALLs. Constitutive activation of NOTCH signaling as result of activating mutations in the NOTCH1 gene is a hallmark of this disease and small molecule gamma-secretase inhibitors, which effectively block activation of the NOTCH1 receptor, have been proposed as targeted therapy. However, the progress of NOTCH1-blocking agents such as in the clinic has been limited. Here we hypothesized that detailed transcriptional profiling of T-ALL lymphoblasts upon inhibition of NOTCH1 signaling would uncover major effector pathways downstream of NOTCH1. Moreover, we proposed that these signatures would facilitate the identification of new drugs and drug combinations for the treatment of T-ALL. Gene expression profiling of NOTCH1 induced leukemias treated with DBZ, a highly active gamma-secretase inhibitor, identified numerous genes regulated by NOTCH1 in human leukemia. Notably these signatures were enriched in NOTCH1 direct target genes such as Hes1 and revealed a prominent role of NOTCH signaling in the control of cellular metabolic pathways. Following on these results we performed Connectiviy map analysis to identify drugs whose transcriptional effects could antagonize those of oncogenic NOTCH1 in human leukemia. This analysis identified HDAC inhibitors, anti-psychotic agents, anti-malarials and compounds targeting the PI3K and NFKB signaling pathways. Detailed analysis of the effects of these drugs alone and in combination with DBZ demonstrated strong antileukemic activity and strong synergism when combined with inhibition of NOTCH signaling with a gamma-secretase inhibitor. Moreover, biochemical and transcriptional profiling of these drugs identifies agents with unique and related mechanisms of action.

Overall these results identify new antileukemic drugs with strongly synergistic activity in combination with NOTCH1 inhibition for the treatment of T-ALL

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):A226.

Citation Format: Marta Sanchez Martin, Alberto Ambesi, Daniel Herranz, Adolfo Ferrando. Identification of new synergistic compounds for the treatment of NOTCH-driven T-ALL. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr A226.
Abstract A227: The involvement of wild-type KIT overexpression in colon cancers.
Authors: Kim Wonkyu , Park Misun , Kim Hogeun
Published: August 2014

Abnormal signaling through receptor tyrosine kinase (RTK) moieties is crucial in tumor progression and drug targeting of colorectal cancers. Wild-type KIT (WT-KIT), a RTK that is activated upon binding with stem cell factor (SCF), is highly expressed in some colon cancers; however, the functional role of SCF-dependent KIT activation is barely understood in colon cancer pathogenesis. In this study, we aimed to determine the conditions and roles of WT-KIT activation in colon cancer tumorigenesis. We found that WT-KIT was expressed in a subset of colon cancer cell lines and was activated by SCF treatment, leading to activation of downstream AKT and extracellular signal-regulated kinase (ERK) signaling pathways. We also demonstrated that KIT expression gradually decreased, after prolonged SCF stimulation, due to lysosomal degradation. Degradation of WT-KIT after SCF binding was significantly rescued when PKC-δ was activated. We also showed that activated PKC-δ directly binds to SCF bound WT-KIT, facilitating the recycling of WT-KIT. We further showed that a subset of colorectal cancers exhibit expressions of both WT-KIT and activated PKC-δ and that expression of KIT is correlated with poor patient survival (P = 0.004). We herein for the first time demonstrated that continuous downstream signal activation after KIT-SCF binding is accomplished through PKC-δ-mediated recycling of KIT. This sustained KIT activation may contribute to tumor progression in a subset of colon cancers with KIT expression and might provide the rationale for a therapeutic approach targeting KIT.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):A227.

Citation Format: Wonkyu Kim, Misun Park, Hogeun Kim. The involvement of wild-type KIT overexpression in colon cancers. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr A227.
Abstract A230: An anti-leishmanial thiadiazine agent induces multiple myeloma cell apoptosis by suppressing the nuclear factor kappaB signaling pathway.
Authors: Chen Guodong , Han Kunkun , Xu Xin , Du Xiaolin , Zhang Zubin , Tang Juan , Shi Min , Wang Man , Li Jie , Cao Biyin , Mao Xinliang
Published: August 2014

Nuclear factor kappaB (NF-κB) is a nuclear transcription factor that regulates expression of a large number of genes critical for cell proliferation, survival, inflammation, and tumorigenesis. Recent evidence indicates that NF-κB and its signaling pathways are constitutively activated both in myeloma cell lines and in primary myeloma cells. Downregulated NF-κB signaling by bortezomib and other compounds has demonstrated that the NF-κB signaling could be a promising therapeutic target of MM. In the present study, we found that one of the tetrahydro-2H-1,3,5-thiadiazine-2-thione (THTT) derivatives displayed potent anti-myeloma activity by inhibiting the NF-κB signaling pathway. DETT downregulated IKKα, β, p65, and p50 expression and inhibited phosphorylation of p65 (Ser536) and IBα. Simultaneously, DETT increased IκBα, an inhibitor of the p65/p50 heterodimer, even in the presence of stimulants lipopolysacharride, tumor necrosis factor alpha or interleukin-6. DETT inhibited NF-κB transcription activity and down-regulated NF-κB targeted genes including Bcl-2, Bcl-XL, and XIAP. Deregulation of NF-κB signaling by DETT resulted in MM cell apoptosis characterized by cleavage of caspase-3, caspase-8, and PARP. Notably, this apoptosis was partly blocked by activation of NF-κB signaling in the presence of TNFα and IL-6. Moreover, DETT delayed myeloma tumor growth in nude mice without overt toxicity. DETT is therefore a potent candidate for MM therapy as an inhibitor of the NF-κB signaling pathway.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):A230.

Citation Format: Guodong Chen, Kunkun Han, Xin Xu, Xiaolin Du, Zubin Zhang, Juan Tang, Min Shi, Man Wang, Jie Li, Biyin Cao, Xinliang Mao. An anti-leishmanial thiadiazine agent induces multiple myeloma cell apoptosis by suppressing the nuclear factor kappaB signaling pathway. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr A230.
Abstract A236: The orphan G-protein coupled receptor GPR161 is an oncogene in triple negative breast cancer.
Authors: Feigin Michael E. , Xue Bin , Hammell Molly , Muthuswamy Senthil K.
Published: August 2014

Triple negative breast cancer (TNBC) accounts for 20% of breast cancer in women and lacks an effective targeted therapy. Therefore, finding common vulnerabilities in these tumors represents an opportunity for more effective treatment. Recent large-scale analyses of hundreds of tumor samples have provided a deluge of information on the genetic changes occurring during tumorigenesis. However, determining which changes drive tumor initiation and progression, and which are bystanders remains a difficult biological problem. Utilizing this genomic information we have discovered that the orphan G-protein coupled receptor (GPCR) GPR161 is overexpressed specifically in TNBC. TNBC patients expressing higher levels of GPR161 have an increased probability of disease relapse. Overexpression of GPR161 in human non-transformed mammary epithelial cells increases cell proliferation and multiacinar structure formation in three-dimensional (3D) culture through activation of mTORC1 signaling. Knockdown of GPR161 impairs proliferation of a human basal breast cancer cell line. Furthermore, GPR161 expression induces cell migration and invasion of cells in 3D culture. This is accompanied by disrupted cell adhesion and intracellular accumulation of E-cadherin. Cells overexpressing GPR161 show a reduction in IQGAP1 phosphorylation, consistent with mTOR activation and E-cadherin disruption. Furthermore, we find GPR161 in a signaling complex with the scaffold proteins β-arrestin 2 and IQGAP1. These results suggest that GPR161 may provide prognostic value and serve as a potential drug target in TNBC.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):A236.

Citation Format: Michael E. Feigin, Bin Xue, Molly Hammell, Senthil K. Muthuswamy. The orphan G-protein coupled receptor GPR161 is an oncogene in triple negative breast cancer. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr A236.
Abstract A239: T-type calcium channels as a novel molecular target for tumor therapy.
Authors: Dziegielewska Barbara , Valerie Nicholas C.K. , Hosing Amol S. , Larner James M. , Brautigan David L. , Gray Lloyd S. , Dziegielewski Jaroslaw
Published: August 2014

T-type Ca2+ channels are a group of low voltage-gated calcium channels which seem to be crucial for embryonic or stem cell proliferation and differentiation; however, they could be also aberrantly expressed in several human tumors. Since calcium entry is required for smooth transition through the cell cycle, it has been hypothesized that the inhibition of T-type Ca2+ channels blocks cells in G0/G1 phase of cell cycle, while a release from inhibition leads to increased number of cells entering cell cycle and thus increased susceptibility to conventional antitumor therapy. In this study we investigated the effects of T-type channel inactivation, or downregulation, on cell cycle progression, cell death and survival, and resistance to radiotherapy (RT). The experiments were conducted using several cancer cell lines expressing T-type Ca2+ channels (glioblastoma, colon and prostate) and selective and structurally unrelated calcium channels antagonists, including Mibefradil, a drug that is currently undergoing clinical trial for its antitumor properties, and is planned to be tested as radiosensitizing agent in recurrent gliobastoma tumors. The effects of T-type Ca2+ channel inhibition on cell cycle progression, cell death and the expression/activation of cell cycle regulated proteins were assessed. Finally, the combination treatments including T-type channel antagonist and radiotherapy were assayed. We show that T-type Ca2+ channels are important for cell cycle progression and resistance to RT, and that their inhibition leads to enhanced cell death and reduced survival. Our study demonstrates that one of the earliest events evoked by T-type channel inhibition is a deregulation of pro-survival pathway PI3K/Akt/mTOR and activation of pro-apoptotic stress-activated p38MAPK pathway. The results support the idea of T-type Ca2+ channel as a novel molecular target for antitumor therapy and provide a rational and plausible biological mechanism responsible for the effects induced by T-type Ca2+ channel antagonists in cancer cells.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):A239.

Citation Format: Barbara Dziegielewska, Nicholas C.K. Valerie, Amol S. Hosing, James M. Larner, David L. Brautigan, Lloyd S. Gray, Jaroslaw Dziegielewski. T-type calcium channels as a novel molecular target for tumor therapy. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr A239.
Abstract A24: Network models of signaling and drug response in melanoma.
Authors: Korkut Anil , Wang Weiqing , Molinelli Evan , Miller Martin , Kaushik Poorvi , Aksoy Arman , Jing Xiaohong , Gauthier Nick , Sander Chris
Published: August 2014

Novel combination therapies are potentially key to preventing emergence of resistance to initially successful single agent therapies such as RAF inhibitors in melanoma. In order to systematically nominate novel and effective drug combinations, we have developed an integrated systems biology technology (perturbation biology) for inferring quantitative and predictive network models of signaling. Our modeling strategy combines systematic perturbation experiments, measurement of response profiles to perturbations, inference of network models and simulation of models with in silico perturbations. As a key component of the overall strategy, we have adapted the belief propagation (BP) inference algorithm from statistical physics to construct signaling models with several hundreds of measured entities. In parallel, we have developed a pathway informatics tool to automatically extract prior information from multiple signaling databases. We applied this approach to derive signaling network models in RAF inhibitor resistant melanoma cells and nominate drug combinations to overcome resistance in melanoma. First, we systematically perturb melanoma cells with a set of targeted drugs as single and paired agents. Next, we quantitatively measured proteomic (total and phospho-protein levels) and phenotypic (e.g. cell cycle arrest, cellular viability) responses to perturbations. We incorporated the generic prior information and context specific perturbation response data to construct quantitative network models, which capture multiple oncogenic pathways in melanoma. As shown by cross validation calculations, use of prior information significantly improved predictive power of models. Using the inferred network models of signaling, we systematically predicted response to tens of thousands of in silico perturbations. Our modeling and simulation strategy expanded the volume of drug response profile from few thousand experimental data points to millions of in silico data points. In addition, our models provided quantitative descriptions of signaling events in melanoma. Our perturbation biology technology is suitable for applications in diverse areas of molecular biology beyond cancer research.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):A24.

Citation Format: Anil Korkut, Weiqing Wang, Evan Molinelli, Martin Miller, Poorvi Kaushik, Arman Aksoy, Xiaohong Jing, Nick Gauthier, Chris Sander. Network models of signaling and drug response in melanoma. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr A24.
Abstract A240: A mechanism linking Id2-TGFβ crosstalk to reversible adaptive plasticity in neuroblastoma.
Authors: Chakrabarti Lina , Wang Bi-Dar , Lee Norman H. , Sandler Anthony
Published: August 2014

The ability of high-risk neuroblastoma to survive unfavorable growth conditions and multimodal therapy has produced an elusive childhood cancer with a remarkably poor prognosis. A novel phenomenon enabling neuroblastoma to survive selection pressure is its capacity for reversible adaptive plasticity. This plasticity allows cells to transition between highly proliferative anchorage dependent (AD) and slow growing anoikis resistant anchorage independent (AI) phenotypes. The differential gene expression profile of the two cellular phenotypes in the mouse Neuro2a cell line delineated pathways of proliferation in AD cells or tyrosine kinase activation/ apoptosis inhibition in AI cells. A 20 fold overexpression of inhibitor of differentiation 2 (Id2) was identified in AD cells while up-regulation of genes involved in anoikis resistance like PI3K/Akt, Erk, Bcl2, and integrins was observed in AI cells. Similarly, differential expression of Id2 and other genes of interest were also observed in the AD and AI phenotypes of human neuroblastoma cell lines, SK-N-SH and IMR-32; as well as in primary human tumor specimens. Forced down-regulation of Id2 in AD cells or overexpression in AI cells induced the cells to gain characteristics of the other phenotype. Id2 binds both TGFβ and Smad2/3 and appears critical for maintaining the proliferative phenotype at least partially through negative regulation of the TGFβ/ Smad pathway. Simultaneously targeting the differential molecular pathways governing reversible adaptive plasticity resulted in cure of established tumors in a mouse model of neuroblastoma. We present a mechanism that accounts for reversible adaptive plasticity and a molecular basis for combined targeted therapies in neuroblastoma.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):A240.

Citation Format: Lina Chakrabarti, Bi-Dar Wang, Norman H. Lee, Anthony Sandler. A mechanism linking Id2-TGFβ crosstalk to reversible adaptive plasticity in neuroblastoma. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr A240.
Abstract A251: MGMT inhibition decreases survivin expression in pancreatic cancer.
Authors: Bobustuc George C. , Patel Anand , Thompson Michael , Kalkunte Srivenugopal S. , Frick Jacob , Weese James , Konduri Santhi D.
Published: August 2014

Survivin is an antiapoptotic gene negatively regulated by p53 tumor suppressor. Survivin is overexpressed in human cancers and one of its functions is to reduce the efficacy of chemotherapy. We report that O6-benzylguanine (BG), a potent inhibitor of MGMT (O6-methyl guanine DNA methyl transferase), a DNA repair protein, curtails the expression of survivin in pancreatic cancer cells. We also show that BG, either alone or in combination with gemcitabine, inhibits survivin and PCNA expression both at the mRNA and protein levels in Panc1 and L3.6pl cells. Further, BG, either alone or in combination with gemcitabine, significantly decreases survivin promoter activity in these cells. We also show that these combinations decrease survivin protein expression in pancreatic tumors derived from orthotopic xenografts developed in nude mice. Immunohistochemistry confirms the reduced expression of survivin and PCNA in tumor sections after BG or BG plus gemcitabine treatments. We also show the enhanced recruitment of p53 protein to the survivin promoter in BG-treated pancreatic cancer cells. Further, BG promotes p53 function leading to growth inhibition. Taken together our data suggests that BG induced partial restoration of p53 activity suppresses survivin function and enhances gemcitabine effect in pancreatic cancer.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):A251.

Citation Format: George C. Bobustuc, Anand Patel, Michael Thompson, Srivenugopal S. Kalkunte, Jacob Frick, James Weese, Santhi D. Konduri. MGMT inhibition decreases survivin expression in pancreatic cancer. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr A251.
Abstract A253: HO-3867, a safe STAT3 inhibitor, is selectively cytotoxic to ovarian cancer.
Authors: Selvendiran Karuppaiyah , Rath Kellie S. , Naidu Shan , Latha Pushpa , Hemant Bid , McCann Georgia A. , Bravo Veronica , Houghton Peter , Leone Gustavo , Hideg Kálmán , Kuppusamy Periannan , Cohn David E.
Published: August 2014

We have developed a novel class of bi-functional compounds based on a diarylidenyl-piperidone (DAP) backbone conjugated to an N-hydroxypyrroline (-NOH; a nitroxide precursor) group which selectively inhibits STAT3 activation, translocation, and DNA binding activity, without affecting the expression of other pSTATs. This new STAT3 inhibitor offers advantages when compared to other STAT3-targeting molecules currently available, under development or undergoing preclinical trials. Most notably, these compounds exhibit minimal toxicity toward normal cells and tissues while inducing apoptosis in ovarian cancer cells, and exhibit good oral bioavailability. Results show that selective cytotoxicity of the lead compound, HO-3867, towards cancer cells is multi-faceted. AutoDock molecular modeling indicates that the DAP compounds interact with STAT3 at the DNA-binding domain. Liquid chromatography / Mass spectroscopy analysis demonstrates greater bioabsorption and bioavailability of active (cytotoxic) metabolites in cancer cells when compared to normal cells. Differential activation of the Akt pathway was demonstrated using Akt siRNA in normal versus cancer cells. Knockdown of STAT3 expression using two different shRNAs shows the requirement of STAT3 for HO-3867-mediated apoptosis. In vivo testing shows that HO-3867 inhibits xenograft tumor growth without toxic side effects. In addition, HO-3867 significantly inhibited cell survival, migration/invasion and induced cell death in primary ovarian cancer cell populations isolated from ascites of patients with recurrent and advanced ovarian cancer. This study provides evidence of a safe, targeted STAT3 inhibitor (HO-3867) with demonstrated efficacy in treating multiple ovarian cancer models. This suggests significant translational potential of these compounds for the treatment of ovarian cancer.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):A253.

Citation Format: Karuppaiyah Selvendiran, Kellie S. Rath, Shan Naidu, Pushpa Latha, Bid Hemant, Georgia A. McCann, Veronica Bravo, Peter Houghton, Gustavo Leone, Kálmán Hideg, Periannan Kuppusamy, David E. Cohn. HO-3867, a safe STAT3 inhibitor, is selectively cytotoxic to ovarian cancer. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr A253.