bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 5383: The plasmonic photothermal therapy efficacy of Au NRs in vivo using a SCCHN xenograft mouse model
Authors: Peng Xianghong , Mackey Megan A. , Oyelere Adegboyega , Zhang Jun , Chen Georgia , Nie Shuming , El-Sayed Mostafa A , Shin Dong M
Published: May 2015

The plasmonic photothermal therapy (PPTT) is promising for the treatment of cancer because it overcomes the challenges in conventional treatments by avoiding drug resistance, surgery infections, and minimizing healthy cell destruction. It is well suited for the treatment of the squamous cell carcinoma of the head and neck (SCCHN) as this type of cancer is readily accessible to NIR light. We have synthesized the Au nanorods (NRs) with different sizes (25nm and 40nm) and modified the particle surface with PEG stabilizer, and conjugated Au NRs with SCCHN-targeted HNSCP peptides. The new Au NRs -assisted PPTT was tested in a SCCHN xenografted tumor model. The SCCHN xenograft tumors were inoculated by injection of 1x106 Tu212 cells subcutaneously into the right flank of nude mice and allowed to grow to approximately 100 mm3. Fifty nude mice were divided into ten groups (n=5) in a way to minimize weight and tumor size differences among the groups: control group treated with PBS (A), laser treatment (diode laser, 808 nm, 1-2 W/cm2, 1cm diameter, 2 min) (B), non-targeted AuNRs ( 25nm size) with (C)or without laser treatment(D), HNSCP-Au NRs(25 nm size) with (E) or without laser treatment( F), non-targeted Au NRs (40 nm size) with (G) or without laser treatment (H), HNSCP-Au NRs(40 nm size) with (I) or without laser treatment (J). Au NRs (25 μL) at concentration of, 25 nM in PBS buffer were injected into mice via intratumoral injection. Our results showed that the Au NRs with laser treatment could significantly inhibit the tumor growth in vivo compared with that of control and laser treatment only groups (without Au NRs). In addition, the tumor targeted Au NRs didn't show enhanced antitumor efficacy compared with the non-tumor targeted Au NRs. The mice showed complete response to the PPTT didn't have tumor relapse after 15 weeks of the treatment. There are no remarkable toxicities observed. (This research was supported by the National Cancer Institute award 5U01CA151802 )

Citation Format: Xianghong Peng, Megan A. Mackey, Adegboyega Oyelere, Jun Zhang, Georgia Chen, Shuming Nie, Mostafa A El-Sayed, Dong M Shin. The plasmonic photothermal therapy efficacy of Au NRs in vivo using a SCCHN xenograft mouse model. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 5383. doi:10.1158/1538-7445.AM2014-5383
Abstract 5386: Disrupting p53:Mdm2 and p53:Mdm4 - Comparative cell-based assays for drug screening
Authors: Yurlova Larisa , Brown Christopher J. , Derks Maarten , Ghadessy Farid John , Hickson Ian , Lane David P. , Krausz Eberhard , Zolghadr Kourosh
Published: May 2015

The important interconnected protein-protein interactions between the tumor suppressor p53 and its regulatory binding partners Mdm2 and Mdm4 (= MdmX/ HdmX) are implicated in pathogenesis of various cancers. However, until now there is a lack of reversible cell-based assays for concurrent analysis for both PPIs: p53/Mdm2 and p53/Mdm4. Our aim was to develop two comparative assays based on the Fluorescent 2-Hybrid (F2H) assay principle, which enable side-by-side analysis of antagonistic compounds.

The F2H assay is a fully reversible microscopy-assisted assay for the direct intracellular analysis of PPIs. It offers a fast and straight-forward readout: an interaction-dependent co-localization of two fluorescent signals at a defined spot in the nucleus of mammalian cells.

With these assays we analyzed a set of newly developed stapled peptides as potent p53:Mdm2 and/ or p53:Mdm4 inhibitors. Live cell data generated by the F2H assays enabled us to discriminate and describe the peptides according to their ability to penetrate into the cells, their efficacy on the PPIs and their cytotoxic side effects in one single assay.

In parallel we performed a pilot F2H screen with a sub-set or 20 small molecule compounds (including Nutlin-3) that exhibited activity against one or both interactions at various potencies in ELISAs before. We could identify 5 potent compounds, which were dramatically reducing the number of p53:Mdm2 interactions. However, none of the small molecules, but only the stapled peptides exhibited an intracellular activity on p53:Mdm4. Furthermore, we were able to expand these assays and to identify mutants of Mdm2 resistant to Nutlin inhibition.

In summary, we show that the p53:Mdm2 and p53:Mdm4 F2H assays described here,

- enable side-by-side analysis of substances' dual Mdm2-Mdm4 activity

- are suitable for screening and testing various types of compounds, such as peptidic inhibitors or small molecules

- concurrently provide initial data on compound cell-permeability and cytotoxicity

- allow real-time visualization of PPI dynamics in living cells.

Citation Format: Larisa Yurlova, Christopher J. Brown, Maarten Derks, Farid John Ghadessy, Ian Hickson, David P. Lane, Eberhard Krausz, Kourosh Zolghadr. Disrupting p53:Mdm2 and p53:Mdm4 - Comparative cell-based assays for drug screening. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 5386. doi:10.1158/1538-7445.AM2014-5386
Abstract 539: Downregulation of hnRNP A1 by miRNAs as a new mechanism of survival in ovarian cancer
Authors: Rodriguez-Aguayo Cristian , Monroig Paloma , Almeida Maria I. , Ivan Cristina , Gonzalez-Villasana Vianey , Shah Maitri Y. , Sood Anil K. , Calin George , Lopez-Berestein Gabriel
Published: May 2015

Background. Posttranscriptional regulation is a critical control point for the expression of genes that promote or retard tumor growth. The mRNA-binding protein hnRNP A1 is required for the processing of miR-18a, an inhibitor of k-ras expression. In this study we hypothesized that downmodulation of hnRNP A1 by miR-25 and miR-15a controls the expression of miR-18a and k-ras by modulating nuclear and cytoplasmic miRNA processing at the posttranscriptional level. Methods. In this study, we determined the expression of hnRNP A1 at mRNA and protein levels in three parental ovarian cancer cells lines (Skov3ip1, HeyA8, and A2780) and their chemotherapy-resistant derivatives (Skov3-TR, HeyA8 MDR, and A2780 cp20). We also predicted in silico which miRNAS can target hnRNP A1 and confirmed the miRNA expression by real-time PCR. Moreover, we inhibited miR-25 and mir-15a to determine their tumorigenic potential in vitro. We also correlated the expression of miR-25 and miR-15a and/or miR-18a and k-ras expression in the TCGA data. Results. Downregulation of hnRNP A1 at the RNA and protein levels was observed in the taxane-resistant cell lines but not in the cisplatin-resistant cell line. Furthermore, we predicted in silico that miR-25and miR-15a can target hnRNP A1 and confirmed the overexpression of these microRNAs in SKOV3-TR (5- and 3-fold, respectively) and HeyA8 MDR (3-fold) by real-time PCR. We also analyzed overall survival, trying to find a correlation between k-ras and miR-15a (high 23.77, low 33.97 months), k-ras and miR-25 (high 16.95, low 35.21 months), and the combination of k-ras, miR-25, and miR18a (k-ras high, miR25 high, mir18a low, 20.73 months; k-ras low, miR25 low, mir18a high, 31.49 months). Comparison of these data with a validation set yielded similar results. Conclusion. These results underscore the importance of a previously uncharacterized circuit of posttranscriptional regulation between miR-25 or -15a and RNA-binding protein hnRNP A1 that regulates miR-18a and k-ras expression. This circuit represents a unique opportunity for novel therapeutics approaches.

Citation Format: Cristian Rodriguez-Aguayo, Paloma Monroig, Maria I. Almeida, Cristina Ivan, Vianey Gonzalez-Villasana, Maitri Y. Shah, Anil K. Sood, George Calin, Gabriel Lopez-Berestein. Downregulation of hnRNP A1 by miRNAs as a new mechanism of survival in ovarian cancer. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 539. doi:10.1158/1538-7445.AM2014-539
Abstract 5391: MT-MMP cleavage profiling using rapid endopeptidase profiling library (REPLi)
Authors: Mitchell Andrew , Giménez-Warren Javier , Shnyder Steven D. , Gill Jason H. , Falconer Robert A. , Loadman Paul M.
Published: May 2015

Matrix metalloproteinases (MMPs) are a family of zinc-dependent endopeptidases that are associated with the metastatic process. Relative to non-diseased tissue, the increased expression and activity of Membrane-type matrix metalloproteinases (MT-MMPs) such as MMP-15 within the prostate tumour microenvironment can be exploited in order to selectively activate highly toxic chemotherapeutics. The main advantage to such a targeted drug delivery system is a significant reduction of systemic toxicity, resulting in a highly efficacious and successful treatment for prostate cancer.

We have screened 3375 peptides with a variety of residue combinations using Rapid Endopeptidase Profiling Library (REPLi). A ‘small but smart’ design, the REPLi library template: MCA-Gly-Gly-Gly-Xaa-Xaa-Xaa-Gly-Gly-DPA-Lys-Lys contains a donor (MCA) and quenching acceptor (DPA) FRET pair. No fluorescence indicates the molecules within the pools are intact, however, upon cleavage, the tri-variable cores can be assessed via auto fluorescence of the MCA molecule.

By analysing the 512 distinct substrate pools we have identified combinations of Phe/Tyr and Asn/Gln residues as having a greater MMP-15 cleavage bias over MMP-14, with the opposite being true for variable cores with Ile/Leu and Lys/Arg combinations. Since most known substrates show little (if any) MMP selectivity this is a novel finding, and as such, provides us with insights that are essential for designing prodrugs targeted to specific MMPs.

Through detailed metabolic studies, this information is being utilised in a bid to maximise the successful development of novel MMP-15 targeted paclitaxel conjugated prostate cancer prodrugs.

Citation Format: Andrew Mitchell, Javier Giménez-Warren, Steven D. Shnyder, Jason H. Gill, Robert A. Falconer, Paul M. Loadman. MT-MMP cleavage profiling using rapid endopeptidase profiling library (REPLi). [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 5391. doi:10.1158/1538-7445.AM2014-5391
Abstract 5393: The advantages of acoustic liquid handling for drug sensitivity screening
Authors: Edwards Bonnie
Published: May 2015

Recently identified associations between variants of cancer genes and drug resistance have increased the value for comprehensive drug sensitivity screening in combination with molecular profiling of cancer cells. This in turn, has led to a demand for improvements to screening throughput and efficiency. Echo® Liquid Handlers use acoustic energy to provide high throughput, non-contact, liquid handling for a range of applications. Non-contact transfer avoids the risk of cross-contamination, eliminates tip costs, and facilitates the progression to high density assay formats. Echo Liquid handlers precisely and accurately transfer 2.5 nL droplets of sample and reagent, which enables the miniaturization of biochemical screens. This poster discusses the implementation of miniaturized drug sensitivity screening, at the Institute of Molecular Medicine in Finland (FIMM), with assay-ready plates produced by the Echo liquid handler.

Citation Format: Bonnie Edwards. The advantages of acoustic liquid handling for drug sensitivity screening. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 5393. doi:10.1158/1538-7445.AM2014-5393
Abstract 5407: Milk derived exosomes: Scalable source of biologically active drug delivery nanoparticles
Authors: Aqil Farrukh , Munagala Radha , Jeyabalan Jeyaprakash , Gupta Ramesh C.
Published: May 2015

Exosomes are biological nanoparticles and found in almost all the body fluids. They shuttle in and out of cells, are comprised of lipid bilayers, and carry a cargo of macromolecules. Because of the nano size (30-100 nm) these natural vesicles are being explored as nanodevices for the development of new therapeutic applications. Here we show bovine milk as a scalable source of exosomes and as a drug delivery vehicle for small molecules - both lipophilic and hydrophilic. The exosomes were isolated by differential centrifugation with the size generally ranging from 30-100 nm as analyzed by NanoSight and confirmed by electron microscopy and atomic force microscopy. The identity of exosomes was confirmed by surface protein markers (CD63, CD81), buoyant floatation density (1.12 g/ml) determined by sucrose density gradient, and high content of immune-related miRNAs and mRNA as determined by PCR. Exosomes, suspended in PBS, and stored frozen (-80°C) were found to be stable in terms of their size and biological activities. Milk exosomes loaded with fluorescent dye were readily taken up by macrophages and human cancer cells in vitro and distributed in the various tissues of nude mice following treatment with gavage and i.v. routes. Imaging of various tissues collected after euthanasia showed a broad tissue distribution of the exosomes delivered via the oral route, whereas exosome concentration predominated in the liver when administered by the i.v. route. Both lipophilic and hydrophilic chemopreventive (curcumin, withaferin A, anthocyanidins, and punicalagins, etc.) and chemotherapeutic (paclitaxel and docetaxel) agents could be loaded onto exosomes with 8%-60% drug load with respect to exosomal protein content. Drug-exosomal formulations showed significantly higher antiproliferative activity against lung, breast and ovarian cancer cells versus the free drugs. The drug formulation also showed significantly higher tissue drug levels, and enhanced anti-inflammatory and antitumor activity versus the free drug. Intriguingly, in the absence of any drug, the milk exosomes showed anti-proliferative and anti-inflammatory activities in cancer cells, suggesting the presence of protective factors in the milk exosomes (e.g., miRNAs); this notion corroborates the epidemiological and experimental findings of the presence of built-in immune factors in milk. (Supported from USPHS grants CA-118114 and CA-125152, Kentucky Lung Cancer Research Program, Agnes Brown Duggan Endowment, and Helmsley Funds).

Citation Format: Farrukh Aqil, Radha Munagala, Jeyaprakash Jeyabalan, Ramesh C. Gupta. Milk derived exosomes: Scalable source of biologically active drug delivery nanoparticles. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 5407. doi:10.1158/1538-7445.AM2014-5407
Abstract 5416: Development of a nanoparticle platform for the targeted delivery of siRNA to HER2-positive breast cancers
Authors: Goodyear Shaun M.
Published: May 2015

Successful siRNA based therapy has the potential to revolutionize cancer therapy by mediating the silencing of any gene deemed important for disease progression. However, unprotected siRNA has a short half-life in blood and lacks the ability to selectively identify target cells. Our group is developing an effective siRNA based nanoparticle platform that overcomes these shortcomings by utilizing a mesoporous silica nanoparticle electrostatically loaded with siRNA and conjugated with an antibody for target homing. The human epidermal growth receptor type 2 (HER2) is a highly validated therapeutic target in breast cancer due to its prognostic role in cancer aggressiveness and drug resistance when overexpressed in tumors. Suppression of HER2 with siRNA based therapy (siHER2) offers a new treatment modality and provides a testable system for the development of our nanoparticle platform. Incorporation of Herceptin, a monoclonal antibody which binds to HER2, serves to selectively target HER2-positive cancer cells. In vitro evaluation of the nanoconstruct loaded with a highly optimized siHER2 sequence against a panel of HER2-positive (HCC1954, JIMT-1, BT474) and HER2-negative (MCF-7, MCF-10A, HDFa) cell lines demonstrated efficient knockdown of HER2 gene expression (> 75% reduction of HER2 mRNA and protein). Concomitant cell viability assays showed increased cell death in HER2-positive and no HER2-negative cell lines further highlighting treatment specificity. Importantly, treatment of cells with the siHER2-nanoconstruct effectively inhibited growth in HER2-positive cell lines resistant to Herceptin and Lapatinib. Subsequent in vivo tumor modeling studies using orthotopic transplantation of HCC1954 in the mammary fat pad of SCID mice revealed that i.v. injection of the siHER2-nanocontruct reduced overall tumor burden. HER2 knockdown in the tumors was also significant. These findings provide the foundation for a novel translational platform for facilitating therapeutic siRNA.

Citation Format: Shaun M. Goodyear. Development of a nanoparticle platform for the targeted delivery of siRNA to HER2-positive breast cancers. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 5416. doi:10.1158/1538-7445.AM2014-5416
Abstract 5419: Computationally-inspired engineering of supramolecular taxane nanoparticles
Authors: Kulkarni Ashish A. , Rao Poornima , Goldman Aaron , Sengupta Shiladitya
Published: May 2015

Clinical efficacy of long circulating lipid nanoparticles depend on high drug to lipid ratio, stability during circulation and sustained drug release after tumor accumulation. Achieving this is the holy grail of paclitaxel (PTX) lipid nanoparticles due to its incompatible physicochemical properties such as bulkiness, structural asymmetry, hydrophobicity that leads to low drug loading efficiency and tendency to crystallize leading to significant instability. Effective strategy to overcome these limitations could be devised by understanding molecular interactions of PTX with lipid bilayer at spatiotemporal level but these remain poorly understood. Here, using computer simulations, we have investigated the interactions of PTX with the model lipid bilayer at low and high drug contents. We found that PTX at low concentrations occupied the space in both hydrophobic and hydrophilic regions of the bilayer and did not exhibit significant destabilizing effect whereas at high concentrations it exclusively accumulated at the hydrophilic tail region causing significant rifts in the bilayer. In silico dynamic simulations showed that conjugation of PTX to cholesterol using a flexible spacer (Suprataxel, STX) stabilized the lipid bilayer at high concentrations. To confirm the theoretical observations, we engineered supramolecular nanoparticles of STX (STX-NP) and characterized the physicochemical and mechanical stability. In vitro efficacy studies showed that STX-NPs is comparable to PTX in multiple cancer cell lines. We demonstrated that STX-NPs were more efficacious than PTX in inhibiting tumor growth in 4T1 breast cancer and K-RasLSL/+/Ptenfl/fl ovarian cancer models. This study shows that the effective Supramolecular nanoparticles could be engineered by understanding the interactions between the drug and the lipid layer.

Note: This abstract was not presented at the meeting.

Citation Format: Ashish A. Kulkarni, Poornima Rao, Aaron Goldman, Shiladitya Sengupta. Computationally-inspired engineering of supramolecular taxane nanoparticles. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 5419. doi:10.1158/1538-7445.AM2014-5419
Abstract 5425: L-amino acid oxidase from Crotalas adamanteus venom induces caspase-independent apoptosis in human NUGC-3 gastric cancer cells
Authors: Ding Jian , Bay Boon-Huat , Gopalakrishnakone P
Published: May 2015

L-amino acid oxidases (LAAOs), which are largely present in snake venoms, are a group of flavoenzymes, known to catalyze oxidative deamination of L-amino acid substrates, resulting in the formation of corresponding α-keto acids, hydrogen peroxide and ammonia. LAAOs have attracted interest in biomedical and pharmacological research because of their antimicrobial, anti-HIV, anticoagulant, inhibition of platelet aggregation and apoptotic-inducing activities. The aim of this study is to evaluate the anticancer effects of LAAO from Crotalas adamanteus snake venom in human NUGC-3 gastric cancer cells in vitro. Cell viability and cytotoxicity were determined by Alamar Blue and Lactate Dehydrogenase assays. Cell cycle phases were analyzed by flow cytometry. Apoptosis was identified by flow cytometric analysis with Annexin-V and PI staining. The morphological changes were observed by fluorescence microscopy, transmission electron microscopy and scanning electron microscopy. The ROS level was quantified by DCFDA staining as well as malondialdehyde formation. The results showed that LAAO reduced cell viability and induced cytotoxicity in a dose-dependent manner. There was associated cell cycle arrest at the G2/M phase. Morphological changes induced by LAAO treatment included membrane blebbing, cell shrinkage and chromatin condensation. Apoptosis induced by LAAO in NUGC-3 gastric cancer cells as evidenced by Annexin-V and PI positive staining, was found to be mediated via a caspase-independent pathway without activating caspase-3 and Poly ADP-ribose polymerase. Moreover, a concomitant increase of intracellular oxidative stress and the translocation of the apoptosis inducing factor (AIF) from mitochondria to the nucleus were observed. It would appear that LAAO derived from the Crotalas adamanteus venom, induced a caspase-independent apoptotic pathway which was incited by ROS and AIF translocation. This study provides new biological insights into the application of LAAO from a snake venom in cancer therapeutics.

Citation Format: Jian Ding, Boon-Huat Bay, P Gopalakrishnakone. L-amino acid oxidase from Crotalas adamanteus venom induces caspase-independent apoptosis in human NUGC-3 gastric cancer cells. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 5425. doi:10.1158/1538-7445.AM2014-5425
Abstract 5430: Frizzled-1 receptor, a potential therapeutic target for atypical teratoid rhabdoid tumor
Authors: Chakravadhanula Madhavi , Ozols Victor , Hampton Chris , Bhardwaj Ratan
Published: May 2015

Atypical Teratoid Rhabdoid Tumors (ATRTs) are aggressive tumor types in the field of pediatric neuro-oncology that need new therapeutic strategies since they are associated with significantly worse overall prognosis than other pediatric tumors. A characteristic feature of ATRTs is usually an aberration of SMARCB1/INI1/hSNF5 gene. One of the important developmental pathways for cellular development is the Wnt pathway. Wnt proteins are a family of 19 secreted glycoproteins and act as ligands that bind transmembrane receptors such as the Frizzled receptors. There are 10 known Frizzled receptors, and the binding of a specific Wnt ligand to a specific Frizzled receptor plays a crucial role in the regulation of diverse cellular processes. Perturbation of the activities of Wnt ligands can result in defects in embryonic development and diseased states such as cancer. In our preliminary transcriptome analyses results, Wnt5b and Frizzled-1 receptor (Fz-1) were significantly upregulated in 20 ATRT samples and 3 ATRT cell lines. The binding of Wnt5b with Fz-1 was further confirmed by immunoprecipitation and Western blotting analyses. Treatment of ATRT cells with Fz-1 specific siRNA did not indicate a significant decrease in cell viability. Similarly treatment of ATRT cells with a Fz-1 specific monoclonal antibody (Fz-1Mab) also did not indicate significant decrease in cell viability. However, in this study treatment of cells with a combination of Fz-1 specific siRNA and Fz-1Mab indicated a significant decrease in cell viability. A dose response analysis was performed over time to test various doses of Fz-1Mab with constant Fz-1 siRNA concentrations; a cell titre glo assay was then performed to assess cell viability. The physiologically relevant Fz-1Mab dose was then used to assess the effects of using this combination treatment on Fz-1 and Wnt5b protein levels. A decrease in Fz-1 and Wnt5b protein levels when Fz-1 receptor is blocked by siRNA and Mab indicates that Wnt5b bound to Fz-1 receptor plays an important role in ATRT disease etiology and could be a therapeutic target.

Citation Format: Madhavi Chakravadhanula, Victor Ozols, Chris Hampton, Ratan Bhardwaj. Frizzled-1 receptor, a potential therapeutic target for atypical teratoid rhabdoid tumor. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 5430. doi:10.1158/1538-7445.AM2014-5430
Abstract 5437: Dual targeting of ErbB-2 and ErbB-3: A new potential strategy for the treatment of pancreatic cancer
Authors: Sala Gianluca , Ghasemi Reza , Capone Emily , Rapposelli Ilario Giovanni , Traini Sara , Rossi Cosmo , Natali Pier Giorgio , Iacobelli Stefano
Published: May 2015

Background: Pancreatic cancer (PC) is one of the most lethal cancers and there is an urgent need to find out new therapeutic approaches. Deregulated signaling through ErbB-1 and ErbB-2, members of the epidermal growth factor receptor family, frequently occurs in PC. However, attempts aiming at inhibiting ErbB-1 and ErbB-2 have revealed only a modest impact on disease outcome. A growing body of evidence suggests that ErbB-3 and its ligand NRG-1β are key players in driving oncogenic signaling and resistance to targeted therapy in PC. We have recently developed a novel humanized ErbB-3 antibody, named EV20, which displayed a potent antitumor activity by promoting receptor downregulation in vitro and in vivo. Here we hypothesized that targeting of ErbB-3 with EV20 would enhance the therapeutic effect of ErbB-2 inhibitors in PC.

Materials and Methods: Three different PC cell lines (BxPC-3, HPAF II and SW1990) were chosen based on their metastatic origin, genetic background (KRAS status) and responsiveness to erlotinib. The expression of ErbB-1, ErbB-2 and ErbB-3 was analyzed by FACS and WB. The effects of trastuzumab, cetuximab, EV20 and their combinations on NRG-1β-induced activation of the ErbB3/PI3K/Akt axis, cell proliferation, and in vivo tumor growth were evaluated by standard procedures.

Results: ErbB-1 was overexpressed by all the cell lines, whereas the expression levels of ErbB-2 and ErbB-3 were moderate in HPAFII cells and low in BxPC-3 and SW1990 cells. NRG-1β was more effective than EGF (an ErbB-1 ligand) in activating ErbB-3 downstream signaling, which was not inhibited by cetuximab, despite a high ErbB-1 expression in the cells. Conversely, inhibition of ErbB-2 and/or ErbB-3 resulted in a marked suppression of NRG-1β-driven Akt activation. Finally, EV20 in combination with trastuzumab exerted a superior antitumor activity compared to single agent alone in terms of cell proliferation and growth of PC xenografts in nude mice.

Conclusions: Dual targeting of ErbB-2 and ErbB-3 could represent a newer therapeutic approach in PC.

Note: This abstract was not presented at the meeting.

Citation Format: Gianluca Sala, Reza Ghasemi, Emily Capone, Ilario Giovanni Rapposelli, Sara Traini, Cosmo Rossi, Pier Giorgio Natali, Stefano Iacobelli. Dual targeting of ErbB-2 and ErbB-3: A new potential strategy for the treatment of pancreatic cancer. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 5437. doi:10.1158/1538-7445.AM2014-5437
Abstract 5440: Activity of mesothelin-targeted immunotoxin RG7787 against triple-negative breast cancer
Authors: Alewine Christine , Maon-Osann Emily , Pastan Ira
Published: May 2015

Mesothelin (MSLN) is a cell surface glycoprotein normally expressed by mesothelial cells of the pleura, pericardium and peritoneum, but also highly expressed in mesothelioma, pancreatic and ovarian cancers. It was recently reported that many triple negative breast cancers (TNBCs) also express MSLN. RG7787 is a next generation, deimmunized recombinant immunotoxin (RIT) consisting of a high-affinity anti-MSLN Fab fragment for targeting, fused to a 24 kD fragment of Pseudomonas exotoxin A for cell killing. Here, we demonstrate using flow cytometry that the TNBC cell lines HCC70 and SUM149 express significant MSLN on the cell surface. HCC70 and SUM149 are sensitive to RG7787 and related RITs with IC50 values in the subnanomolar range. RG7787 has less off-target toxicity in mice than earlier mesothelin-targeted immunotoxins and could be safely administered to mice at six-fold higher doses. RG7787 shrinks HCC70 tumor xenografts grown in athymic nude mice by >40% and produces a 10 day delay in tumor progression compared to vehicle (p < 0.02). Tumor volume decreased by >85% when RG7787 was given following paclitaxel, a statistically significant improvement over paclitaxel alone. Together these data demonstrate that RG7787 has significant activity against TNBC and warrants further study as a treatment for this malignancy.

Citation Format: Christine Alewine, Emily Maon-Osann, Ira Pastan. Activity of mesothelin-targeted immunotoxin RG7787 against triple-negative breast cancer. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 5440. doi:10.1158/1538-7445.AM2014-5440
Abstract 5446: FPA144: A therapeutic antibody for treating patients with gastric cancers bearing FGFR2 gene amplification
Authors: Gemo Abigael T. , Deshpande Amit M. , Palencia Servando , Bellovin David I. , Brennan Thomas J. , Patil Namrata S. , Huang Carol , Los Gerrit , Pierce Kristen L.
Published: May 2015

A subset of patients with gastric cancer have an amplification of the receptor tyrosine kinase fibroblast growth factor receptor 2 (FGFR2) gene. The amplification is most common in the diffuse type of gastric cancer and its presence correlates with poor patient prognosis. Although it has been reported that there is high expression of FGFR2 protein in patients with the amplification, it has been unknown which of the two major FGFR2 isoforms, FGFR2b or 2c, is expressed. In this study, we demonstrate, by both qPCR and immunohistochemistry using FGFR2b-selective antibodies, that it is the FGFR2b isoform, and not FGFR2c, that is overexpressed in gastric cancer tumors that contain the FGFR2 amplification.

Five Prime Therapeutics has developed an FGFR2b-specific antibody, FPA144, to treat patients with gastric cancers bearing amplification of the FGFR2 gene. FPA144 is glycoengineered for enhanced antibody-dependent cell cytotoxicity (ADCC). FPA144 causes tumor growth inhibition by 72% to 100% in gastric cancer xenograft models with FGFR2 gene amplification that overexpress the FGFR2b protein isoform. In the SNU-16 model, FPA144 reduces the levels of FGFR2b protein expressed in the tumors by approximately 50%, and decreases both FGFR2b phosphorylation and phosphorylation of the downstream effector, FRS2. The anti-tumor effect of FPA144 is additive with the standard of care chemotherapy regimens of 5-fluoruracil/cisplatin and paclitaxel in the OCUM-2 gastric cancer xenograft model. Since FPA144, unlike small molecule FGFR tyrosine kinase inhibitors, blocks signaling by only the FGFR2b and not the other FGFRs, we expect a favorable toxicology profile, either alone or in combination with chemotherapy. In addition, by engaging immune effector cells for direct tumor cell killing, FPA144 has a second mechanism of action that small molecule FGFR tyrosine kinase inhibitors do not have. We anticipate starting clinical trials of FPA144 in the last quarter of 2014.

Citation Format: Abigael T. Gemo, Amit M. Deshpande, Servando Palencia, David I. Bellovin, Thomas J. Brennan, Namrata S. Patil, Carol Huang, Gerrit Los, Kristen L. Pierce. FPA144: A therapeutic antibody for treating patients with gastric cancers bearing FGFR2 gene amplification. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 5446. doi:10.1158/1538-7445.AM2014-5446
Abstract 5449: FP-1039/GSK3052230, an FGF ligand trap, enhances VEGF antagonist therapy in preclinical models of RCC and HCC
Authors: Bellovin David I. , Palencia Servando , Hestir Kevin , Lee Ernestine , DeYoung M. Phillip , Brennan Thomas , Los Gerrit , Baker Kevin
Published: May 2015

An increasing body of evidence has implicated FGF2 as one of the drivers of resistance to various inhibitors of VEGF-mediated angiogenesis. This resistance may play a role as a key limitation to the efficacy of therapies targeted at VEGF and its receptors. We investigated the potential for FP-1039/GSK3052230, a ligand trap that sequesters FGFs and inhibits their signaling, to enhance the activity of VEGF antagonist therapies in certain preclinical models of renal cell (RCC) and hepatocellular (HCC) carcinomas. First, we examined whether FP-1039/GSK3052230 has single agent efficacy against human RCC and HCC xenografts that express relatively high levels of FGF2, a profile that would mimic FGF2-driven resistance to VEGF therapy. We determined that this expression profile represents 34% of clear cell RCC (ccRCC) and 31% of HCC patients, based on the cancer genome atlas (TCGA) data. Human ccRCC xenografts with high FGF2 expression and low VEGFA expression demonstrated a significant inhibition in tumor growth when treated with FP-1039/GSK3052230 alone (TGI: 39-81%). In addition, we show that the high FGF2 expression profile is similarly predictive for the anti-tumor response of a human HCC model to single-agent FP-1039/GSK3052230 (TGI: 31-55%). In contrast, RCC models with low FGF2 expression, representing 66% of all ccRCC in the TCGA, are relatively insensitive to FP-1039/GSK3052230 as a single-agent. However, combination therapy of FP-1039/GSK3052230 with pazopanib in these tumors is significantly more effective than either agent alone. FP-1039/GSK3052230 not only slows tumor growth, but can induce ∼25% tumor regression when administered to mice bearing ccRCC xenografts that have become resistant to pazopanib. Together, our data demonstrate that FP-1039/GSK3052230 may be an effective therapy against RCC and HCC, both as a single agent in disease driven by FGF2 and in combination with VEGF antagonist therapies that represent the current standards of care for advanced disease.

Citation Format: David I. Bellovin, Servando Palencia, Kevin Hestir, Ernestine Lee, M. Phillip DeYoung, Thomas Brennan, Gerrit Los, Kevin Baker. FP-1039/GSK3052230, an FGF ligand trap, enhances VEGF antagonist therapy in preclinical models of RCC and HCC. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 5449. doi:10.1158/1538-7445.AM2014-5449
Abstract 5455: Resistance to a MEK inhibitor (AZD6244): Its association with increased expression of transcription factor 4
Authors: Goo Bon-Kwan , Hur Eun-Hye , Choi Yunsuk , Kim Sung-Doo , Hwang Jung Jin , Kim Choung-Soo , Bae Kyun Seop , Choi Jene , Cho Suk Young , Yang Sang-Hwa , Lee Je-Hwan
Published: May 2015

The important role of Ras/Raf/MEK/ERK pathway in carcinogenesis has led to clinical development of MEK inhibitors for treatment of various cancers. Although recent studies have demonstrated impressive antitumor activities of the agents, many tumors show intrinsic and acquired resistance to MEK inhibitors. We tried to find biomarkers that were associated with intrinsic or acquired resistance to a MEK inhibitor (AZD6244) by public microarray data acquisition and development of AZD6244-resistance cell lines. First, we analyzed a set of genome-wide gene expression profiling data from 6 sensitive and 6 resistant cell lines of various tissue origins to identify candidate genes whose expression changes are associated with resistant or sensitive responses to AZD6244. Of 62 differentially expressed genes, we selected Transcription Factor 4 (TCF4) gene as a potential drug resistance marker for further analysis because degree of increased expression of TCF4 in resistance cell lines was relatively high and a previous study suggests that TCF4 functions as an oncogene in human colon cancers. The mRNA levels of TCF4 in AZD6244 resistant cell lines were significantly elevated than those in sensitive cell lines. The siRNA was used for the targeted silencing of TCF4 to elucidate the role of increased expression of TCF4 in intrinsic resistance to AZD6244. TCF4 siRNA significantly enhanced susceptibility of a AZD6244-resistant cell line, LOXIMVI, to AZD6244. Next, we established AZD6244-resistant cell lines, using originally AZD6244-senstive cell lines, M14 and COLO-205. The half maximal inhibitory concentration (IC50) values for AZD6244 in two acquired resistant cell lines were 34 fold and 200 fold higher than those of their parent cell lines, respectively. Protein levels of TCF4 in the acquired resistant cell lines were higher than those in the sensitive parent cell lines. Our study results suggest that increase expression of TCF4 may be associated with both intrinsic and acquired resistance to MEK inhibitors.

Citation Format: Bon-Kwan Goo, Eun-Hye Hur, Yunsuk Choi, Sung-Doo Kim, Jung Jin Hwang, Choung-Soo Kim, Kyun Seop Bae, Jene Choi, Suk Young Cho, Sang-Hwa Yang, Je-Hwan Lee. Resistance to a MEK inhibitor (AZD6244): Its association with increased expression of transcription factor 4. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 5455. doi:10.1158/1538-7445.AM2014-5455
Abstract 546: CD44 variant expression is a poor prognostic marker in early gastric cancer and well-differentiated gastric cancer
Authors: Lee Won Sup , Go Se-Il , Lee Jeong-Hee , Jeong Sang-Ho , Lee Young-Joon , Hong Soon Chan , Ha Woo Song , Ko Gyung Hyuck
Published: May 2015

The present study is to investigate the significance of the expression of CD44 variant (CD44v), a functional cancer stem cell marker, in the primary gastric cancer. We first tested whether CD44v is selectively expressed in gastric cancer tissue. With the tissue microarray samples containing the 6 normal tissue, 6 H. pylori associated gastritis, 12 intestinal metaplasia, 12 low-grade adenoma, 12 high-grade adenoma, 25 early gastric cancer and 26 advanced gastric cancer. The positive expression rates in tumor were 65.3% (49/75) whereas the positive rates in normal and gastritis tissue were 30.4% (p = 0.003). Next, we investigated the clinical significance of gastric cancer with the tissue microarray containing 333 gastric cancer tissue derived from the patients who underwent radical gastrectomy for gastric cancer from 1999 to 2007. The positive expression rates of CD44v (55%, 134/242) were higher in intestinal type gastric cancer than in diffuse type (28%, 21/76). Intestinal type gastric cancer among the CD44v-positive gastric cancer accounted for 82% (134/164). The 5-year survival rate of CD44v-positive gastric cancer was 67.7% whereas that of CD44v-negative gastric cancer was 62.9%. The survival difference was higher as time passed, but it was statistically insignificant (p = 0.219). However, in the subgroup analysis we found that the survival differences were significantly higher in early gastric cancer and well-differentiated gastric cancer (p = 0.013, 5-YSR ; p = 0.046, 5-YSR , respectively). We also investigated the correlation between the expressions of CD44v and EGFR along with the well-known proliferative molecular biomarkers, cylin D1 and Ki-67. Only the expression of Ki-67 were some correlation with CD44v expression in gastric cancer; CD44v-positive rates of the cancers with negative or 1 positive Ki-67 expression were 37% (47/127) whereas those with 2 or 3 positive Ki-67 expression were 57.4% (116/202). This study demonstrates that CD44v can be a good biomarker for early gastric cancer and well-differentiated gastric cancer. [This study was supported by a grant from the National R&D Program for Cancer Control, Ministry for Health, Welfare & Family Affairs, Republic of Korea. (0820050).]

Citation Format: Won Sup Lee, Se-Il Go, Jeong-Hee Lee, Sang-Ho Jeong, Young-Joon Lee, Soon Chan Hong, Woo Song Ha, Gyung Hyuck Ko. CD44 variant expression is a poor prognostic marker in early gastric cancer and well-differentiated gastric cancer. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 546. doi:10.1158/1538-7445.AM2014-546
Abstract 5469: Trastuzumab resistant HER2+ breast cancer cells retain sensitivity to poly (ADP-ribose) polymerase (PARP) inhibition
Authors: Wielgos Monica E. , Cooper Tiffiny , Forero Andres , Bonner James A. , Esteva Francisco J. , Osborne C K. , Schiff Rachel , LoBuglio Albert F. , Yang Eddy S.
Published: May 2015

Background: Overexpression of HER2 in breast cancer is associated with aggressive tumor features and poor patient survival. Current therapeutic agents targeting this receptor have increased the survival rate of patients with HER2+ breast cancer; however some patients eventually develop resistance to these therapies. We have previously reported that HER2+ breast cancers are susceptible to poly (ADP-Ribose) polymerase inhibitors (PARPi) alone independent of a basal or induced DNA repair deficiency but instead via suppression of NF-κB signaling. In this study, we investigated PARPi sensitivity in HER2+ breast cancer cells that are resistant to the HER2 targeted agent trastuzumab.

Materials and Methods: HER2+ breast cancer cell lines BT-474, UACC812, SKBRR3 and their trastuzumab resistant counterparts were used in this study. Cells were treated with vehicle or 10µM ABT-888 or transfected with scrambled or PARP1 siRNA. NF-κB transcriptional activity was measured using a NF-κB-driven luciferase reporter assay. Protein expression was measured by Western blot analysis. Cellular cytotoxicity and viability following PARPi was assessed with colony formation and ATPlite assays, respectively.

Results: HER2+ parent and trastuzumab resistant breast cancer cells showed similar susceptibility to the PARPi ABT-888. There was a dose response reduction in survival fraction (greater than 70% at 10μM) and a greater than 40% decrease in cell viability with 10μM ABT-888. This cytotoxicity was associated with more than 50% attenuation of NF-κB transcriptional activity and reduced expression of the NF-κB activator IKKα. Suppression of NF-κB signaling was also observed utilizing PARP1 siRNA.

Conclusions: HER2+ breast cancer cells resistant to trastuzumab continue to be sensitive to PARP inhibition through attenuation of the NF-κB signaling pathway. These results support the use of PARPi as part of a therapeutic strategy for patients with HER2+ breast cancer.

Citation Format: Monica E. Wielgos, Tiffiny Cooper, Andres Forero, James A. Bonner, Francisco J. Esteva, C K. Osborne, Rachel Schiff, Albert F. LoBuglio, Eddy S. Yang. Trastuzumab resistant HER2+ breast cancer cells retain sensitivity to poly (ADP-ribose) polymerase (PARP) inhibition. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 5469. doi:10.1158/1538-7445.AM2014-5469
Abstract 5470: LKB1 loss sensitizes non-small cell lung cancer cells to aggravation of ER stress
Authors: Inge Landon J. , Friel Jacqueline M. , Fowler Aaron , Richer Amanda , Whitsett Timothy , Tran Nhan L. , Bremner Ross M.
Published: May 2015

Five-year survival rates for non-small cell lung cancer (NSCLC) have seen minimal improvement despite aggressive therapy with standard chemotherapeutic agents, indicating a need for new treatment approaches. Studies show inactivating mutations to the LKB1 tumor suppressor are common in NSCLC and are concurrent with activating mutations to the KRas oncogene. Genetic and mechanistic analyses of KRas/LKB1-null NSCLC tumors suggest these tumors are a phenotypically distinct subpopulation of NSCLC and the unique features of KRas/LKB1-null tumors have potential for therapeutic gain. In the exploration of the mechanism(s) behind increased cytotoxicity of KRas/LKB1-null NSCLC cells to 2-D-Deoxyglucose (2DG), we find that loss of LKB1 in NSCLC cells imparts increased sensitivity to pharmacological aggravation of ER stress. In a panel of NSCLC cell lines, LKB1 expression status correlated to differential expression of the ER stress markers, BiP and CHOP, with 2DG treatment. Treatment of isogenic LKB1-null NSCLC cells ectopically expressing LKB1 or a nonfunctional LKB1 with the ER stress activators, tunicamycin (Tm) or brefeldin A (BFA), revealed that expression of LKB1 increased cell viability and phosphorylation of AMPK. Conversely, isogenic LKB1-null NSCLC cells expressing nonfunctional LKB1 displayed increases in phosphorylation of the ER stress marker, eif2α and markers of ER stress mediated cell death (reactive oxygen species and cleaved caspase-9) following aggravation of ER stress with 2DG, Tm or BFA. The use of 2DG was effective in controlling the growth of KRas/LKB1-null tumors compared to KRas/LKB1-expressing tumors in transgenic NSCLC models and 2DG-treated KRas/LKB1-null NSCLC tumors displayed features consistent with 2DG treatment of in vitro KRas/LKB1-null NSCLC cell lines. Based upon these findings, we suggest that KRas/LKB1-null NSCLC tumors are more sensitive to pharmacological aggravation of ER stress and this approach has potential as a treatment for NSCLC patients whose tumors are defined as KRas/LKB1-null.

Citation Format: Landon J. Inge, Jacqueline M. Friel, Aaron Fowler, Amanda Richer, Timothy Whitsett, Nhan L. Tran, Ross M. Bremner. LKB1 loss sensitizes non-small cell lung cancer cells to aggravation of ER stress. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 5470. doi:10.1158/1538-7445.AM2014-5470