bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract C91: Targeting enzalutamide resistance in prostate cancer.
Authors: Ketola Kirsi , Bishop Jennifer , Gleave Martin , Zoubeidi Amina
Published: August 2014

Prostate cancer initially responses to androgen ablation or castration, but progression to incurable castrate-resistant prostate cancer often occurs within three years. Androgen receptor pathway inhibitor Enzalutamide (ENZ) has produced promising survival gains of patients with CRPC. However, resistance to this novel therapy also rapidly occurs and novel treatment strategies are needed. We have recently developed a unique ENZ and castrate-resistant LNCaP xenograft model. To identify key regulators and active pathways in ENZ resistant cells, genome-wide gene expression analysis was performed and analyzed using systems biological approaches. We identified that forkhead box M1 (FOXM1) is one of the key upstream regulators activated in ENZ resistant prostate cancer cells. FOXM1 is overexpressed in several cancers and it is an important regulator of cancer characteristics such as cell cycle, proliferation, invasion, metastases and cancer stem cells. FOXM1 is also a critical regulator of oxidative stress and its depletion sensitises cells to oxidative stress induced apoptosis. Interestingly, we further found out that the antibiotic ionophore and oxidative stress inducer monensin that was previously identified as a cancer-specific prostate cancer inhibitor in high-throughput screening, reduces FOXM1 pathway activity and viability of ENZ resistant cells. Thus, the results suggest that inhibition of FOXM1 is a potent novel mean to impair redox control and target ENZ resistant prostate cancer cells. Taken together, our results indicated that FOMX1 activity is increased in ENZ resistant prostate cancer cells and that targeting FOXM1 is a potential means to overcome ENZ resistance in prostate cancer.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):C91.

Citation Format: Kirsi Ketola, Jennifer Bishop, Martin Gleave, Amina Zoubeidi. Targeting enzalutamide resistance in prostate 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 C91.
Abstract C94: Heterogeneous mechanisms of acquired resistance to anti-EGFR therapies in colorectal cancer are sensitive to concomitant inhibition of EGFR and MEK.
Authors: Misale Sandra , Arena Sabrina , Lamba Simona , Siravegna Giulia , Lallo Alice , Hobor Sebastijan , Russo Mariangela , Buscarino Michela , Sartore-Bianchi Andrea , Bencardino Katia , Amatu Alessio , Siena Salvatore , Di Nicolantonio Federica , Bardelli Alberto
Published: August 2014

Monoclonal antibodies targeting EGFR are used in the clinic to treat KRAS wild type metastatic colorectal cancer (CRC). After an initial response, secondary resistance occurs thereby limiting the clinical benefit of these drugs. Relapsed patients have no further therapeutic options, therefore, elucidating the molecular basis of resistance is a prerequisite for the development of further lines of therapy.

We took advantage from a panel of CRC cell lines sensitive to EGFR inhibition by treating with cetuximab or panitumumab until resistant derivatives emerged. The resistant populations were heterogeneous mixture of cells bearing different alterations in KRAS, NRAS and BRAF genes at various frequencies. An RNA interference (siRNA) genetic screening unveiled that suppression of MEK1/2 together with silencing of EGFR was effective in impairing the growth of the resistant cells. Combinatorial treatment with pimasertib, a selective allosteric MEK inhibitor, together with cetuximab re-sensitizes anti-EGFR resistant derivatives despite the genetic alterations heterogeneity. Combinatorial treatment was effective in vitro and in vivo both in cell derived xenografts and in an acquired resistant patient derived xenograft (xenopatient).

These observations provide a rational strategy to overcome the multifaceted clonal heterogeneity that emerges when tumors are treated with targeted agents. We propose that MEK inhibitors, in combination with cetuximab or panitumumab, should be tested in clinical trials in CRC patients who become refractory to anti-EGFR therapies.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):C94.

Citation Format: Sandra Misale, Sabrina Arena, Simona Lamba, Giulia Siravegna, Alice Lallo, Sebastijan Hobor, Mariangela Russo, Michela Buscarino, Andrea Sartore-Bianchi, Katia Bencardino, Alessio Amatu, Salvatore Siena, Federica Di Nicolantonio, Alberto Bardelli. Heterogeneous mechanisms of acquired resistance to anti-EGFR therapies in colorectal cancer are sensitive to concomitant inhibition of EGFR and MEK. [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 C94.
Abstract C99: Wogonin enhanced reactive oxygen species-induced apoptosis and potentiated cytotoxic effects of chemotherapeutic agents by Nrf2 suppression in HepG2 cells.
Authors: Qian Chen , Hu Rong
Published: August 2014

Abstract: Cancer cells, compared to normal cells, are under increased oxidative stress with higher level of ROS. When exposed to environmental or intracellular stresses like ROS, NFE-related factor 2 (Nrf2) is the key to antioxidant response by transcriptionally activate various detoxification and antioxidant enzymes. We have previously shown that wogonin (5,7-Dihydroxy-8-methoxy-2-phenyl-4H-1-benzopyran-4-one), a flavonoid isolated from the root of Scutellaria baicalensis Georgi, could reverse drug resistance in MCF-7/ DOX cells through blocking the translocation of Nrf2 into nucleus, however, the effects of wogonin on Nrf2 signaling pathway have not previously been reported. In our study, we observed that wogonin reduced Nrf2 nuclear translocation, and therefore elevated the level of intracellular ROS to accomplish the purpose of killing malignant cells. In order to confirm the roles of Nrf2, it was activated by tBHQ and knocked down by the Nrf2 siRNA, and the results demonstrated that the activation of Nrf2 was involved in the wogonin-induced accumulation of ROS and cell death. Furthermore, the suppression of Nrf2 by wogonin can potentiate cytotoxic effects of chemotherapeutic agents in HepG2 cells. On one hand, down-regulation of Nrf2 lead to reduction of cytoprotective effect through inducing phage II enzymes which sensitize cells to chemotherapeutic agents. On the other hand, inhibition of multidrug resistance-associated protein (MRPs) by wogonin to enhance the effective drug level in cancer cells is another way to potentiates chemotherapeutic effects. At last, we found that the down-regulation of Nrf2 is associated with over-expression of p53. Using p53 siRNA to knock down the endogenous p53 expression, the level of both c-Myc and Nrf2 in nucleus increased when exposed to wogonin. The present study indicated that wogonin can be used in chemotherapy not only because its own antitumor ability, but also due to the enhanced cytotoxic effects of chemotherapeutic agents.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):C99.

Citation Format: Chen Qian, Rong Hu. Wogonin enhanced reactive oxygen species-induced apoptosis and potentiated cytotoxic effects of chemotherapeutic agents by Nrf2 suppression in HepG2 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 C99.
Abstract CN02-01: CTCs in small cell lung cancer: Biomarkers and biology.
Authors: Dive Caroline
Published: August 2014

Tumor biopsies from lung cancer patients are challenging, particularly so in metastatic disease and development of informative minimally invasive biomarkers are much needed. In this presentation I will review the current status of CTCs in lung cancer as prognostic, predictive and pharmacodynamic biomarkers. The presentation will then focus on Small Cell Lung Cancer (SCLC), an aggressive, neuroendocrine tumor with early dissemination and dismal prognosis accounting for 15-20% lung cancer cases and ∼200,000 deaths globally each year. Most cases are inoperable and biopsies to interrogate SCLC biology are rarely obtained. Improved treatment outcomes for SCLC patients requires new approaches to interrogate the biology and genetics of the disease, appropriate methods to investigate the rapid onset of acquired resistance to current chemotherapy and tractable, patient derived models with which to test new therapies. Circulating tumor cells (CTCs) are prevalent in SCLC. I will describe how we isolate a molecularly profile single CTCs and discuss the development of our new CTC mouse. These new models that can be generated longitudinally from patients at diagnosis and at relapse, together with an analysis of CTC heterogeneity will facilitate a thorough investigation of the mechanisms of acquired drug resistance, and may identify new targets for improved therapy.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):CN02-01.

Citation Format: Caroline Dive. CTCs in small cell lung cancer: Biomarkers and biology. [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 CN02-01.
Abstract CN04-02: Discovery of Mcl-1 inhibitors using fragment-based methods.
Authors: Fesik Stephen W.
Published: August 2014

Mcl-1, a member of the Bcl-2 family of proteins, is overexpressed and amplified in several cancers and causes the aberrant survival of tumor cells that would otherwise undergo programmed cell death and resistance to many chemotherapeutic agents. Down-regulation of Mcl-1 by RNA interference inhibits cell growth, induces apoptosis in cancer cells, and decreases tumorgenicity in mouse xenograft models. Although very potent inhibitors of Bcl-2/Bcl-xL (ABT-263, Navitoclax) and Bcl-2 (ABT-199) have progressed to the clinic, no Mcl-1 inhibitors have entered clinical trials. In this presentation, the discovery of potent Mcl-1 inhibitors using fragment-based methods and structure-based design will be described.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):CN04-02.

Citation Format: Stephen W. Fesik. Discovery of Mcl-1 inhibitors using fragment-based methods. [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 CN04-02.
Abstract ED01-01: Somatic alterations in human cancer genomes.
Authors: Meyerson Matthew L.
Published: August 2014

The advent of high-throughput genome sequence analysis has enabled systematic discovery of somatic genome alterations through genome, exome, and transcriptome sequencing of paired human cancer and germline nucleic acids. These discoveries have led to the identification of somatic genome alterations in new pathways including epigenetic regulators, RNA splicing factors, and immune response regulators, in addition to previously known signal transduction, cell cycle, and transcriptional pathways. I will discuss alterations in these pathways by copy number disruption, mutation, and re-arrangement, especially as seen through the lens of recent and ongoing large-scale studies of lung adenocarcinoma and squamous cell lung carcinoma genomes, from The Cancer Genome Atlas and beyond– and will discuss the implications for the understanding of cancer pathogenesis and for the development of targeted and immunomodulatory therapies.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):ED01-01.

Citation Format: Matthew L. Meyerson. Somatic alterations in human cancer genomes. [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 ED01-01.
Abstract PL05-04: Temporal evaluation of cancer heterogeneity.
Authors: Mardis Elaine R.
Published: August 2014

Next-generation, massively parallel sequencing is enabling an exploration of how cancer genome heterogeneity is changing over time. This approach provides the rough equivalent of techniques that explore species evolution by monitoring the ebb and flow of genomic profiles in the tumor cell population under various influences. One such influence is the application of therapy, which takes many forms from cytotoxic chemotherapy to hormone therapy to targeted, small molecule therapy. Another influence is the temporal study of tumor evolution as the primary evolves to established metastases. I will provide examples from our work of each of the aforementioned scenarios, illustrating how deep sequencing can aid in tracking the evolution of tumor cell genomic profiles.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):PL05-04.

Citation Format: Elaine R. Mardis. Temporal evaluation of cancer heterogeneity. [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 PL05-04.
Abstract PL06-01: Liquid biopsies to monitor response and resistance to targeted therapies.
Authors: Bardelli Alberto
Published: August 2014

The advent of the EGFR-targeted monoclonal antibodies cetuximab and panitumumab paved the way to the individualized treatment of metastatic colorectal cancer (mCRC). In the last 5 years it has become evident that mCRCs respond differently to EGFR-targeted agents and that the tumor-specific response has a genetic basis. After the initial response, secondary resistance invariably ensues, thereby limiting the clinical benefit of anti-EGFR therapies. Understanding the molecular bases of secondary resistance to cetuximab and panitumumab is required to design additional therapeutic options. We found that molecular alterations in KRAS, NRAS, BRAF, and MET are causally associated with the onset of acquired resistance to anti-EGFR blockade in colorectal cancers. We optimized a diagnostic platform to identify resistance-associated genetic alterations in the blood of patients (liquid biopsy) months before radiographic documentation of disease progression. Preclinical models of relapse including cell lines and patient-derived xenografts (xenopatients) allowed us to assess new lines of therapy. Overall our results provide the rationale for delaying or reversing resistance to anti EGFR therapies in mCRCs and support the initiation of innovative– molecularly driven– clinical trials.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):PL06-01.

Citation Format: Alberto Bardelli. Liquid biopsies to monitor response and resistance to targeted therapies. [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 PL06-01.
Abstract PL07-03: Mechanisms of protective tumor immunity.
Authors: Dranoff Glenn
Published: August 2014

Efficacious cancer immunotherapies will likely require combinations of strategies that enhance tumor antigen presentation and antagonize negative immune regulatory circuits. We demonstrated that vaccination with irradiated, autologous melanoma cells engineered to secrete GM-CSF followed by antibody blockade of CTLA-4 accomplishes clinically significant tumor destruction with minimal toxicity in a majority of stage IV metastatic melanoma and some advanced ovarian carcinoma patients. The extent of tumor necrosis in post-treatment biopsies was linearly related to the natural logarithm of the ratio of infiltrating CD8+ effector T cells to FoxP3+ Tregs, suggesting that further Treg inhibition might increase the frequency of clinical responses. Through an analysis of cytokine deficient mice, we delineated a critical role for GM-CSF in Treg homeostasis. GM-CSF is required for the expression of the phosphatidylserine binding protein MFG-E8 in antigen presenting cells, whereas the uptake of apoptotic cells by phagocyte-derived MFG-E8 maintains peripheral Treg activity. The pharmacologic inhibition of MFG-E8 function through genetic or engineering-based approaches blocks Treg induction, which intensifies vaccine-induced responses, leading to the regression of established tumors in mice. The clinical translation of these therapeutic strategies to Phase I testing in humans is underway.

The detailed analysis of patients achieving sustained clinical benefits from irradiated, autologous GM-CSF secreting tumor cell vaccines and CTLA-4 antibody blockade also affords a rich opportunity to identify antigens associated with immune-mediated tumor destruction and to delineate mechanisms of therapeutic immunity. We elucidated several of the molecular pathways that underlie these antitumor effects, including the NKG2D system and multiple secreted/or cell surface proteins that contribute to tumor promoting inflammation. The therapy-induced antibodies manifest functional activity in vitro, antagonizing tumor cell survival, invasive potential, and angiogenesis. These findings support a key role for humoral immunity in tumor destruction, and highlight interest in more detailed characterization of the antitumor B cell repertoire in vaccinated patients.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):PL07-03.

Citation Format: Glenn Dranoff. Mechanisms of protective tumor immunity. [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 PL07-03.
Abstract PR01: Approach for targeting Ras with small molecules that activate SOS-mediated nucleotide exchange.
Authors: Burns Michael , Sun Qi , Daniels Richard , Kennedy J. Phillip , Camper DeMarco , Phan Jason , Olejniczak Edward , Lee Taekyu , Waterson Alex , Rossanese Olivia , Fesik Stephen
Published: August 2014

Aberrant activation of the small GTPase Ras by oncogenic mutation or constitutively active receptor tyrosine kinases (RTKs) results in the deregulation of cellular signals governing growth and survival in cancer. The guanine nucleotide exchange factor Son of Sevenless (SOS) catalyzes the rate-limiting step in the activation of Ras by exchanging GDP for GTP. SOS is therefore a key control point for the propagation of RTK and Ras signaling. Here we report the discovery of small molecules that bind to a unique pocket on the Ras:SOS:Ras complex, increase SOScat-catalyzed nucleotide exchange, and perturb Ras signaling pathways in cells. X-ray crystallographic studies of Ras:SOS:Ras complexed with these small molecules reveal that they bind in a hydrophobic pocket in the CDC25 domain of SOS adjacent to the Switch II region of Ras. The structure-activity relationships exhibited by these compounds can be rationalized on the basis of the x-ray structures of multiple co-complexes. In addition, structure-based mutational analyses indicate that this newly identified pocket is essential for compound activity. As predicted, these molecules increase Ras-GTP levels in cells. However, they unexpectedly inhibit MAPK and PI3K signaling. Our studies suggest a novel way to target K-Ras and offer possible starting points for the discovery of compounds that could be used to treat Ras-driven tumors.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):PR01.

Citation Format: Michael Burns, Qi Sun, Richard Daniels, J. Phillip Kennedy, DeMarco Camper, Jason Phan, Edward Olejniczak, Taekyu Lee, Alex Waterson, Olivia Rossanese, Stephen Fesik. Approach for targeting Ras with small molecules that activate SOS-mediated nucleotide exchange. [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 PR01.
Abstract PR02: LEE011: An orally bioavailable, selective small molecule inhibitor of CDK4/6– Reactivating Rb in cancer.
Authors: Kim Sunkyu , Loo Alice , Chopra Rajiv , Caponigro Giordano , Huang Alan , Vora Sadhna , Parasuraman Sudha , Howard Steve , Keen Nicholas , Sellers William , Brain Christopher
Published: August 2014

The tumor suppressor Retinoblastoma protein (Rb) is often inactivated in cancer. In many tumors, the Rb protein itself is retained but functionally inactivated by increased CDK4/6 kinase activity. A number of key oncogenic aberrations can result in this increased activity, including inactivation of CDKN2A (p16), translocation or amplification of D-cyclins, amplification of CDK4/6 and mutations/deletions upstream of cyclin D, such as activating mutations of BRAF/PIK3CA and PTEN deletion. Abolishing CDK4/6 kinase activity and subsequent reactivation of Rb in these tumors has been demonstrated to inhibit tumor initiation and growth. Here we will describe LEE011- an orally bioavailable, selective small molecule inhibitor of CDK4/6 kinases. LEE011 inhibits CDK4/6 kinase activity with nM IC50 and is highly selective for these targets. In a number of preclinical tumor models, LEE011 demonstrates a dose dependent anti-tumor activity that tracks well with CDK4/6 inhibition. The primary mechanism for growth inhibitory effect appears to be G1 arrest in vitro, although, in some sensitive in vivo models, regressions are observed. Importantly, given the role of CDK4/6 downstream of other oncogenic driver mutations, LEE011 shows single agent activity in melanomas with activating mutations of BRAF or NRAS, and in breast cancers with intact estrogen receptor and/or activating aberrations of PIK3CA/Her-2. Combining LEE011 with LGX818, a V600E BRAF specific inhibitor, leads to robust anti-tumor activity in melanoma models that are both sensitive and, importantly, those that are resistant to LGX818. Furthermore, combining LEE011 with BYL719, a PIK3CA specific inhibitor, also leads to significant anti-tumor activity in breast cancer models both sensitive and resistant to BYL719. Several clinical studies evaluating LEE011 as single agent and in combinations are underway.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):PR02.

Citation Format: Sunkyu Kim, Alice Loo, Rajiv Chopra, Giordano Caponigro, Alan Huang, Sadhna Vora, Sudha Parasuraman, Steve Howard, Nicholas Keen, William Sellers, Christopher Brain. LEE011: An orally bioavailable, selective small molecule inhibitor of CDK4/6– Reactivating Rb in 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 PR02.
Abstract 1750: Identification of genes involved in chemoradiation response of head and neck cancer by functional genetic screens
Authors: Martens-de Kemp Sanne R. , Brink Arjen , van der Meulen Ida H. , Kuik Dirk J. , Menezes Renee , Braakhuis Boudewijn JM , van Beusechem Victor W. , Brakenhoff Ruud H.
Published: August 2014

Introduction: Patients with advanced head and neck squamous cell carcinoma (HNSCC) are treated with cisplatin-containing chemoradiation protocols, but tumor responses can be short-lasting. For these patients surgery combined with postoperative radiotherapy is preferred over chemoradiation. Currently, there are no strong predictors of chemoradiation response that would allow to personalize treatment. We performed a functional genetic siRNA screen to identify genes that can be used to predict upfront which tumors are likely to respond to chemoradiation.

Methods: A large panel of HNSCC cell lines was characterized for cisplatin sensitivity. A suitable HNSCC cell line was selected and forward transfected with a genome-wide library of short interfering RNAs (siRNAs), followed by cisplatin (IC20 and IC80) or mock treatment. Genes influencing cellular response to cisplatin were identified by comparing cell viability between the different conditions. The screen was carried out in duplicate and data were analyzed by Z-score calculation using two independent statistical methods.

Results: Scrambled siRNAs and siRNAs targeting genes known to influence cell viability or cisplatin sensitivity were included as controls and gave the expected results: less than 10% toxicity and >80% knock-down. Hit lists obtained with both methods of data analysis revealed 86 siRNAs that appeared to influence cisplatin response significantly. Some of these 86 siRNAs target genes that are known to cause sensitivity to cisplatin, thereby confirming the reliability of the approach. We also obtained a list of 80 genes that influenced basic cell viability of HNSCC cells independent of cisplatin.

Conclusion: By specifically knocking down all human genes in HNSCC cells, we obtained an unbiased list of at least 86 candidate genes that seem to influence the cellular response to cisplatin. Refined statistical analysis combined with bioinformatics, the exclusion of off-target effects, as well as confirmation of the hits in multiple cell lines is needed to validate these results. Validated hits will be evaluated as predictive markers in clinical samples.

This research was supported by the Center for Translational Molecular Medicine (AIRFORCE project).

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1750. doi:10.1158/1538-7445.AM2011-1750
Abstract 1751: Engineered toxin bodies with specific cell kill activity against mesenchymal cells
Authors: Higgins Jack P. , Robinson Lee , Higley John , Grant Kari , Null Bill , Zhu Keng , Kim Jason , Cunningham Casey , Poma Eric
Published: August 2014

The epithelial-to-mesenchymal transition is associated with progression and poor outcome in numerous cancers. Discovery of selective agents that target mesenchymal cancer cells has been an area of significant interest. Here we describe the identification of several novel compounds that specifically recognize and kill H358 Non-small cell lung carcinoma (NSCLC) cells that have been transitioned to a mesenchymal phenotype while showing no activity against H358 epithelial cells. These compounds were identified from a screen of a novel biologic library derived from a de-immunogenized Shiga-like toxin 1 A subunit (SLT1A); SLT1A has no intrinsic binding ability of its own but can drive internalization, retrograde transport to the cytosol, and enzymatic inhibition of ribosome activity. This modified library of engineered toxin bodies (ETBs) was created through the insertion of random amino acids near the C-terminus of the SLT1A scaffold to confer selective binding ability of SLT1A while preserving the therapeutic PK and ADME profile of the scaffold. This library of approximately 10⁁15 variants was pre-cleared against epithelial H358 cells and then screened against mesenchymal H358 cells. The screen was performed in an etiology driven manner where the receptor was not known a priori and selection was based on variants ability to induce cell-kill. Sequence convergence was observed as a result of the biopanning and further characterization of a selected group of mesenchymal-specific ETBs is on-going.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1751. doi:10.1158/1538-7445.AM2011-1751
Abstract 1752: Nonclinical safety and pharmacokinetics of Sym004: A synergistic anti-EGF receptor antibody mixture
Authors: Skartved Niels Jørgen , Pedersen Mikkel W. , Jacobsen Helle , Jørgensen Thomas K. , Kragh Michael
Published: August 2014

Epidermal growth factor receptor (EGFR) is a well validated oncology target for monoclonal antibodies (mAb's). Symphogen is developing a novel and more efficacious anti-EGFR therapy to treat cancer patients with EGFR-dependent tumors. Sym004 is a recombinant antibody product consisting of a 1:1 mixture of two chimeric IgG1 mAb's targeting non-overlapping epitopes of EGFR. Preclinical proof-of-concept studies have shown that the Sym004 mixture is superior to existing anti-EGFR mAb's currently in clinical use (1).

The nonclinical safety data of Sym004 are presented. The studies were designed to evaluate toxicity and pharmacokinetics of Sym004 as well as the individual antibodies comprising Sym004. No apparent accumulation was observed upon weekly dosing of Sym004 to non-human primates for eight consecutive weeks, whereas, a prolonged half life and accumulation were noted for both of the individual antibodies if these were administered alone. Weekly administration of Sym004 to non-human primates was well tolerated although dose limiting toxicity was observed in a dose-range-finding toxicology study. In a head-to-head comparison with the licensed anti-EGFR mAb, cetuximab (Erbitux®), weekly administration of Sym004 did not induce any distinct or novel adverse findings in the animals. However, and in accordance with the enhanced pharmacological profile of Sym004, an accelerated onset of anticipated anti-EGFR-mediated effects (skin rash and liquid faeces) was observed compared to cetuximab. None or only minor effects were observed in the animals treated with the individual antibodies comprising Sym004. All experimental observations, except a single case of rash, showed reversibility during the 4-week treatment free recovery period. In tissue cross reactivity studies, Sym004 had a staining pattern similar to cetuximab in a full tissue panel from both human and non human primates.

In conclusion, Sym004 is considered to be safe, and the nonclinical safety data supported the initiation of the currently ongoing Phase I/II trial.

1. Pedersen MW et al. Cancer Res; 70(2) January 15, 2010

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1752. doi:10.1158/1538-7445.AM2011-1752
Abstract 1757: MEDI-573, an IGF-I/II neutralizing human antibody inhibits both IGF-1R and IR-A signaling pathways
Authors: Gao Jin , Chesebrough Jon W. , Incognito Leonard , Coats Steven , Bosslet Klaus , Jallal Bahija , Chang Yong S.
Published: August 2014

Insulin-like growth factors (IGF), IGF-I and IGF-II, are small polypeptides involved in regulating cell proliferation, survival, differentiation and transformation. IGF activities are mediated through binding and activation of IGF-1R or insulin receptor isoform A (IR-A). Overexpression of IGF-II and IR-A has been reported in multiple types of cancer, and has also been proposed as a potential mechanism for cancer cells to develop resistance to IGF-1R targeting therapy. MEDI-573 is a dual targeting human antibody that neutralizes both IGF-I and IGF-II. We have shown previously that this antibody inhibits IGF-1R activation by IGF and demonstrated potent in vivo tumor growth inhibition activity in IGF driven xenograft models. Here we show that MEDI-573 inhibits IGF-II activated IR-A signal pathways without cross reactivity to insulin, and therefore has minimum impact on glucose metabolism, which is mediated mainly by insulin/IR interaction. MEDI-573 blocks the binding of IGF-II to, and inhibits the subsequent phosphorylation of IR-A and IRS-1. MEDI-573 inhibited IGF-II-induced in vitro growth of IR-A overexpressing cells with or without the presence of up to 10uIU of insulin in the medium. In addition, MEDI-573 inhibited IGF-II-induced proliferation of IR-A-overexpressing cells as effectively as it inhibited the IGF-1R-overexpressing cells. The anti-proliferative activity of MEDI-573 is not changed across heterogeneous mixed cell populations with various ratios of IR-A- versus IGF-1R-expressing cells. In contrast, an IGF-1R specific antibody was most active at inhibiting the proliferation of a pure IGF-1R expressing homogenous population, but lost activity when the heterogeneous cell population contained increasing percentages (25-50%) of IR-A-expressing cells. We also examined the relative abundance of IR-A versus IR-B (insulin receptor isoform B) mRNA in multiple cancer cell lines using a previously published quantitative RT-PCR method. The results show that IR-A is frequently the dominant isoform overexpressed in these cancer cells. Taken together, these results demonstrate that by neutralizing IGF-I and IGF-II ligands, MEDI-573 is a dual targeting antibody that offers an effective approach to selectively target both the IGF-1R and IR-A signaling pathways and potentially overcome IGF-1R targeting resistance.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1757. doi:10.1158/1538-7445.AM2011-1757
Abstract 1764: DOTA-conjugated antibodies for scintigraphic evaluation of new anti cancer treatments
Authors: Raguin Olivier , Moreau Mathieu , Collin Bertrand , Brunotte François , Tizon Xavier , Duchamp Olivier , Boschetti Frederic , Denat Franck
Published: August 2014

Introduction: The treatment of cancer is being revolutionized by the development of targeted therapeutic biologics. Translational pharmaco-imaging represents a key step in the evaluation of these new targeted anti cancer therapies. In this respect, we have implemented and validated an antibody radiolabeling process for scintigraphic SPECT imaging.

Methods: A new macrocyclic reagent (DOTAGA, bearing an anhydride function able to react with primary amines) was used for DOTA conjugation of Trastuzumab®. DOTA Trastuzumab was synthesized by directly reacting DOTAGA with Trastuzumab®. The number of DOTA per antibody was determined using mass spectrometry.

The DOTA-conjugated antibodies were metallated with Indium-111. The functionality of DOTA Trastuzumab analogs was evaluated by in vitro saturation assays using two human breast cancer cell lines (SK BR 3 and HCC1954).

Results: Two DOTA- Trastuzumab analogs were synthesized. The first analog was bearing one DOTA per antibody while the second was bearing 4 DOTA per antibody. The labeling yield reached 90% for both conjugates and high specific activities were obtained (400 MBq/mg). The affinity of the DOTA Trastuzumab analogs, determined on Her2 expressing SK BR 3 and HCC1954 cell lines, was 1 nM and was similar to that of Trastuzumab®. SPECT imaging experiments in tumor bearing rodents are in progress for in vivo validation of the two analogs.

Conclusion: Together, these results demonstrate the efficiency of our new DOTA-synthesis and conjugation processes for biologics radiolabeling to assess biodistribution, anti-cancer efficacy and related toxicity of anti-cancer drugs by in vivo non invasive imaging.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1764. doi:10.1158/1538-7445.AM2011-1764
Abstract 1767: Targeting prostate cancer osteoblastic progression with VEGF121/rGel, a single agent targeting osteoblasts, osteoclasts, and tumor neovasculature
Authors: Mohamedali Khalid A. , Li Zhi Gang , Starbuck Michael W. , Wan Xinhai , Yang Jun , Kim Sehoon , Zhang Weihe , Navone Nora M. , Rosenblum Michael G.
Published: August 2014

Purpose: A hallmark of prostate cancer (PCa) progression is the development of osteoblastic bone metastases, which respond poorly to available therapies. We previously reported that VEGF121/rGel targets osteoclast precursors and tumor neovasculature. Here we tested the hypothesis that targeting non-tumor cells expressing the receptors for VEGF121, namely VEGFR-1 and VEGFR-2, can inhibit tumor progression in a clinically relevant model of osteoblastic PCa.

Experimental Design: We examined the effect of VEGF121/rGel on osteoblast precursors and several PCa cell lines in vitro; on osteoid formation in a mouse calvaria culture assay ex vivo; and on PCa osteoblastic progression in the femurs of mice injected with MDA PCa 118b, a PCa xenograft obtained from a bone metastasis in a patient with castrate-resistant PCa.

Results: VEGF121/rGel was cytotoxic in vitro to osteoblast precursor cells. This cytotoxicity was specific as VEGF121/rGel internalization into osteoblasts was VEGF121 receptor driven. Furthermore, VEGF121/rGel significantly inhibited PCa-induced bone formation in a mouse calvaria culture assay. In vivo, systemic administration of VEGF121/rGel significantly inhibited the osteoblastic progression of PCa cells in the femurs of nude mice. Microcomputed tomography analysis revealed that VEGF121/rGel restored the bone volume fraction of tumor-bearing femurs to values similar to those of the contralateral (non-tumor bearing) femurs. VEGF121/rGel significantly reduced the number of tumor-associated osteoclasts but did not change the numbers of peritumoral osteoblasts. Importantly, VEGF121/rGel-treated mice had significantly less tumor burden than control mice did. Our results thus indicate that VEGF121/rGel inhibits osteoblastic tumor progression by targeting angiogenesis, osteoclastogenesis, and bone formation.

Conclusions: Targeting VEGFR-1- or VEGFR-2-expressing cells is effective in controlling the osteoblastic progression of PCa in bone. These findings provide the basis for an effective multitargeted approach for metastatic PCa. We believe that VEGF121/rGel in combination with tumor cell-targeting therapies (e.g., chemotherapy) constitutes a novel strategy for advanced PCa. Research conducted, in part, by the Clayton Foundation for Research.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1767. doi:10.1158/1538-7445.AM2011-1767
Abstract 1778: Anticancer activities and regulatory effects on apoptotic gene expression of Bufalin in the orthotopic transplantation model of human colorectal cancer in nude mice
Authors: Wang Jie , Feng Dian-Xu , Chen Chao , Ni Zhen-Hua , Zhao Ronghua , Zuo Qing-Song , Chen Ya-Feng , Wang Xu , Zhang Yong , Casson Alan G. , Chen Teng
Published: August 2014

Background: Bufalin, a natural small-molecule compound from the Traditional Chinese Medicine “Chansu”, shows inhibitory effects on many human cancer cells. However, whether or not Bufalin has anticancer activity in human colorectal cancer (CRC), and its possible underlying mechanism, remains unclear.

Objectives: 1) To investigate anticancer activities of Bufalin in human CRC using an orthotopic transplantation model in nude mice and 2) to study possible underlying mechanisms related to apoptosis.

Materials and methods: An orthotopic transplantation tumor model was established by implanting human CRC HCT-116 cells into the colon of nude mice. Sixty mice were randomly divided into five treatment groups (12 mice in each group): normal saline group, 5-FU group, and 3 Bufalin groups with low (BL), medium (BM), and high (BH) doses. After cell transplantation, 0.2 ml normal saline, 25 mg/kg 5-Fu, or 0.5 mg/kg, 1 mg/kg, 1.5 mg/kg Bufalin was injected intraperitoneally in mice in each corresponding group, daily for 7 days (days 15 to 21). Six mice in each group were sacrificed on day 24. Tumor size, growth inhibition rate, and morphological changes of tumor cell under microscopy were recorded. Apoptosis was determined by TUNEL staining, mRNA and protein expressions of Bcl-xl and Bax were evaluated with real-time RT-PCR and immunohistochemical staining, respectively. The overall survival (OS) was determined in the remaining 6 mice in each group.

Results: The tumor size in mice treated with 5-Fu, BL, BM, or BH was significantly smaller than that in mice treated with normal saline (p<0.05), with the tumor inhibitor rates of 64.3%, 51.4%, 48.7%, and 36.3%, respectively. Under microscopy, increased tumor necrosis was observed in the 5-Fu, BM and BH groups. The tumor apoptotic rate in each of 3 Bufalin treated groups was significantly higher than that in the normal saline group (p<0.05). Real time RT-PCR and immunohistochemical staining showed both mRNA and protein expressions of Bcl-xl were decreased, whereas the expression of Bax increased, in tumor treated with Bufalin. The OS was prolonged in groups of BL and BM (p<0.05).

Conclusion: Bufalin has significant anticancer activity in a human CRC orthotopic transplantation model in nude mice, and induces tumor cell apoptosis, which may be associated with the down-regulation of Bcl-xl and up-regulation of Bax in tumor cells.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1778. doi:10.1158/1538-7445.AM2011-1778
Abstract 1779: Selective oncolysis of multiple myeloma cells by reovirus is mediated through apoptosis
Authors: Thirukkumaran Chandini M. , Shi Zhong-Qiao , Luider Joanne , Kopciuk Karen , Morris Don
Published: August 2014

Introduction: Multiple myeloma (MM) is an incurable hematologic malignancy that accounts for 10% of hematopoietic neoplasms. Recently we have demonstrated the potential of reovirus as novel therapeutic agent for MM, however, the oncolytic mechanism has not been elucidated yet. Reovirus is known to utilize multiple signalling pathways for cancer cell destruction depending on histological origin. It is currently unknown if the apoptotic signalling pathways are involved in reovirus mediated cell death of multiple myeloma.

Methods: The MM cell lines RPMI 8226, U266, NCIH929, HUNS-1, MC/CAR, and OPM2 were incubated with live or UV-inactivated reovirus at a multiplicity of infection of 40 for 24, 48, and 72 hours respectively. Apoptosis was assayed by Annexin V/7-AAD expression and DNA fragmentation using flow cytometry. RPMI 8226 was further investigated at 2, 6 12, 24 and 48 hours for the presence of Phospho -Akt and activated caspase 3 post reovirus infection.

Results: RPMI 8226, U266, and NCIH929 demonstrated an apoptotic response to reovirus infection within 24 hours. All 3 cell lines showed statistically significant (all F tests, p<0.00001) increases in DNA fragmentation in response to reovirus and this increase was more pronounced as time progressed. Similarly expression of Annexin V was significantly higher (all F tests, p<0.00001) in all 3 cell lines with live reovirus treatment but the kinetics were cell line dependent where a significant (p< 0.05) time effect was seen for U266 but not for RPMI 8226 and NCIH929. In contrast, the MM cell lines HUNS-1, MC/CAR, and OPM2 appeared resistant to reovirus infection and showed no evidence of apoptosis at 72 h. Supporting the apoptotic mechanism of cell death, RPMI 8226 showed down regulation of the anti-apoptotic signalling protein, Phospho-Akt, at 24 hours of incubation with reovirus. This was accompanied by a simultaneous expression of activated caspase 3.

Conclusion: Not all MM cell lines are amenable to reovirus mediated cell death. This has important implications for the future use of reovirus as a therapeutic agent for cancer and highlights the importance of understanding cell signalling mechanisms as Phase 3 clinical trials of solid tumours with reovirus are currently underway. Ongoing research utilizing pharmacologic and molecular inhibitors of Akt and caspase3 will enable us to confirm the importance of these molecules in reovirus oncolysis of haematological malignancies. Understanding these signalling pathways will help develop a more personalized approach of reovirus therapy for cancer patients in the future.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1779. doi:10.1158/1538-7445.AM2011-1779
Abstract 178: Pre-treatment with histone deacetylase inhibitor HDACI) synergizes the anti-cancer effect of sorafenib in renal cell carcinoma cells
Authors: Kim Dong Eun , Kim Mi Joung , Jang Sejin , Lee Je-Hwan , Choi Jene , Ro Seonggu , Kim Choung-Soo , Hwang Jung Jin
Published: August 2014

Background: Renal cell carcinoma (RCC), account for 3% of all adult malignances and 75% of RCCs are clear cell renal cell carcinoma (ccRCC), which are highly vascularised tumors. Although a multi-kinase inhibitor, sorafenib has been used for treatment of advanced renal cell carcinoma, it has limitation such as toxicity and long term resistance. Recently, it was reported that histone deacetylase (HDAC) activity is increased in cancer, which leads to suppression of the genes that are related to tumor suppressor and differentiation. Therefore, histone deacetylase inhibitors (HDACIs) are considered as a new anti-cancer drug. In this study, we evaluated the effect of HDACI on anti-tumor effect of sorafenib in ccRCC cells.

Materials and Methods: We used various types of RCC cells including Caki-1(VHL+/+), ACHN (VHL+/+), 786-O (VHL−/−), A498 (VHL−/−), SN12C, TK-10, RXF393, and MDR-over-expressing UO31 cells. We calculated the viability of RCC cells treated with HDACIs (belinostat or vorinostat) alone or in combination with sorafenib using MTS Assay. Combination indexes were determined by CalcuSyn software. We analyzed activation of caspases, and the levels of Mcl-1, Bcl-xl, p-Erk by Western Bolt. Levels of secreted vascular endothelial growth factor (VEGF) were measured by ELISA kit.

Results: Mono-treatment with HDACI (belinostat or vorinostat) induced apoptosis via activation of intrinsic and extrinsic pathways in all RCC cells. Moreover, pre-treatment with belinostat or vorinostat synergistically potentiated cell death induced by sorafenib in Caki-1 and 786-O ccRCC cells. The combination treatment activated caspase-8, -3 and -9 and down-regulated Mcl-1, Bcl-xl, phosphorylation of Erk (p-Erk) and secretion of VEGF in Caki-1 and 786-O cells.

Conclusions: HDACI alone induced apoptotic cell death in various RCC cells. In addition, combination treatment with HDACIs and sorafenib represented synergistic anti-cancer effect in ccRCC cells, indicating that this combination may be a new therapeutic modality for RCC.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 178. doi:10.1158/1538-7445.AM2011-178