bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 712: Immune checkpoint inhibitor induced tumor gene expression changes in murine syngeneic colon cancer models
Authors: Fadden Patrick , Weitzel Douglas , Davis Kelli , Bui Thi , Hurtado David , Haines Hannah , Roark Rhiannon , Derrick Ashleigh , Godfrey Beverly , Belle Ian , Krontz Katherine , Sokolowski Cristina , Synnott Aidan , Wood Edgar
Published: August 2018

The success of immune checkpoint therapy with anti-PD-1 and anti-CTLA-4 antibodies has generated broad interest in immuno-based interventions for oncology. Preclinical efficacy assessment of these novel immune-oncology therapies requires a functional immune system and therefore is frequently performed in murine syngeneic tumor models. In addition to tumor growth inhibition, syngeneic tumor models provide a platform to investigate the mechanism of action for a given novel therapeutic target. Characterization and mechanism of action for immune-based cancer therapies in murine syngeneic tumor models is often assessed by flow cytometry; measuring changes in tumor infiltrating leukocyte (TIL) populations following treatment induction. We assessed whether transcriptomic gene expression analysis could identify additional relevant biomarkers for immunotherapy response. Mice bearing subcutaneous syngeneic colon cancer tumors were dosed intraperitoneally with either vehicle alone, anti-CTLA-4, anti-PD-1, or a combination of the two immune checkpoint inhibitors on days 1, 4, and 8. Tumors were harvested on day 9 and half from each group were assessed for TIL population composition by flow cytometry and half by Clariom D mouse transcriptome array analysis. We identified a number of immune cell-related genes with differential expression that correlated to the therapeutic response and were consistent with changes identified in TIL populations by flow cytometry. These results provide an additional metric for assessing immunotherapy response in vivo. In addition, these data suggest that a smaller, defined panel of gene targets may be developed as biomarkers for specific immune system responses to immune checkpoint therapies in murine syngeneic models.

Citation Format: Patrick Fadden, Douglas Weitzel, Kelli Davis, Thi Bui, David Hurtado, Hannah Haines, Rhiannon Roark, Ashleigh Derrick, Beverly Godfrey, Ian Belle, Katherine Krontz, Cristina Sokolowski, Aidan Synnott, Edgar Wood. Immune checkpoint inhibitor induced tumor gene expression changes in murine syngeneic colon cancer models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 712.
Abstract 713: Upregulation of immune checkpoint molecules on Treg cells in tumor microenvironment reinforces immune exhaustion in cancer patients
Authors: Kim Hye Ryun , Park Hyo Jin , Son Jimin , Shim Hyo Sup , Cho Byoung Chul , Rha Sun Young , Ha Sang-Jun
Published: August 2018

Purpose: Regulatory T (Treg) cells perform the immune suppressive function in cancer, but their suppressive mechanism in tumor microenvironment (TME) has not been clearly elucidated. We aim to identify the phenotype and functional mechanism of Treg cells in TME from cancer patients.

Experimental Design: We collected 72 malignant effusion (ME) and peripheral blood (PB) specimens from stage IV cancer patients and 10 tumor tissue (TM) and PB from lung cancer patients who underwent surgery. Lymphocytes from ME, TM, and PB were analyzed for subtype of Tconv and Treg cells, and their expressions of immune checkpoint (IC) molecules including programmed death (PD-1), cytotoxic T lymphocyte antigen-4 (CTLA-4), and T cell immunoglobulin containing molecule-3 (TIM-3) using by flow cytometry. To examine the functional role of PD-1 expressed Treg cells, TC-1 lung cancer mouse model was used.

Result: Upregulation of PD-1 on Treg cells in TM and ME compared to PB was even more distinguishable than that on CD4+ and CD8+ Tconv cells. To clarify the characteristics of tumor infiltrating Treg cells, we comprehensively examined the characteristics of Treg cells from tumor, peri-tumor, and PB in lung cancer patients by analyzing the expression of IC molecules including PD-1, TIM-3, CTLA-4, and TIGIT, of which PD-1 is the highest expressed on tumor infiltrating Treg cells. To investigate the mechanism by which Treg cells mediate immune suppression, we compared the suppressive activity of Treg cells expressing high and low levels of PD-1 by co-culturing each population with naïve CD8+ T cells with or without αCD3/CD28 stimulation. This was more potently inhibited in co-cultures with PD-1high tumor infiltrating Treg cells than in those with PD-1low Treg cells. PD-1 blocked tumor infiltrating Treg cells demonstrated a significantly decreased suppressive function in the proliferation of CD8+ cells and their IFN-γ production. These results implicate that PD-1 expressed tumor infiltrating Treg confers the suppressive function of proliferation in CD8+ T cells through PD-1: PD-L1 interaction.

Conclusion: Our study evidently demonstrated that upregulated PD-1 on tumor infiltrating Treg cells and their PD-1: PD-L1 interaction could be potential cause of T cell suppression, which might be helpful to completely understand their suppressive mechanism in cancer patients.

Citation Format: Hye Ryun Kim, Hyo Jin Park, Jimin Son, Hyo Sup Shim, Byoung Chul Cho, Sun Young Rha, Sang-Jun Ha. Upregulation of immune checkpoint molecules on Treg cells in tumor microenvironment reinforces immune exhaustion in cancer patients [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 713.
Abstract 728: Optimization of peptide vaccines to induce robust antitumor CD4 T-cell responses
Authors: Kumai Takumi , Sultan Hussein , Kobayashi Hiroya , Harabuchi Yasuaki , Celis Esteban
Published: August 2018

Substantial evidence indicates that immunotherapy is a feasible and effective approach for the treatment of numerous types of cancer. Among various immunotherapy options, peptide vaccines to generate antitumor T cells appear as promising candidates, because of their cost effectiveness and ease of implementation. Nevertheless, most peptide vaccines are notorious for being weekly immunogenic and, thus, optimization of the vaccination strategy is essential to achieve therapeutic effectiveness. In addition, effective peptide vaccines must stimulate both CD8 cytotoxic and CD4 helper T lymphocytes. Our group has been successful in designing effective peptide vaccination strategies for inducing CD8 T-cell responses in mouse tumor models. Here, we describe a somewhat similar, but distinct, peptide vaccination strategy capable of generating vast CD4 T-cell responses by combining synthetic peptides with toll-like receptor (TLR) agonists and OX40/CD40 costimulation. This vaccination strategy was efficient in overcoming immune tolerance to a self-tumor- associated antigen and generated significant antitumor effects in a mouse model of malignant melanoma. The optimized peptide vaccine also allowed the expansion of adoptively transferred CD4 T cells without the need for lymphodepletion and IL-2 administration, generating effective antimelanoma responses through the enhancement of proliferative and antiapoptotic activities of CD4 T cells. These results have practical implications in the design of more effective T-cell-based immunotherapies.

Citation Format: Takumi Kumai, Hussein Sultan, Hiroya Kobayashi, Yasuaki Harabuchi, Esteban Celis. Optimization of peptide vaccines to induce robust antitumor CD4 T-cell responses [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 728.
Abstract 751: A controlled affinity-guided ADC-linker (MAGNET) technology
Authors: Gupta Nimish , Biswas Goutam , Sengupta Aniruddha , Roy Monideepa , Roy Sudip , Sengupta Shiladitya
Published: August 2018

Antibody-drug conjugates (ADCs) have emerged as a powerful technology in cancer therapy. However, challenges with current linker technologies have limited the repertoire of ADCs. Currently-used linkers result in a heterogeneous mixture, unstable conjugates and/or involve complex processes such as genetic modification of the antibodies. Here, for the first time, we have explored high affinity non-covalent interactions between antibody and affinity ligands to design novel linkers that overcome the above challenges. The affinity ligands-based linkers coupled with payload, enable strong non-covalent association with the antibodies owing to their high specificity and affinity for antibodies without the need for any chemical reaction with the antibody. With a prototype affinity ligand, we demonstrated that the affinity ligand is able to guide the payload to six precise locations on the antibody conferring site-specificity to the resulting ADCs. Significantly, despite non-covalent interactions, the conjugates were found to be stable in presence of albumin and in human plasma. The ADC exhibited excellent antigen-specific internalization and nanomolar potency in vitro and were effective in suppressing tumor growth in a lung adenocarcinoma xenograft model with minimal systemic toxicity. This novel technology, which we term MAGNET (multivalent, affinity-guided antibody-empowerment technology) overcomes the existing limitations of ADC engineering by imparting trinity of (1) site-specificity, (2) stability and (3) homogeneity, while simplifying the ADC synthesis process. The self-assembled MAGNET ADCs pave the way for exploration of non-covalent conjugation of payloads to any biomolecule, and heralds a new paradigm for ADC generation.

Citation Format: Nimish Gupta, Goutam Biswas, Aniruddha Sengupta, Monideepa Roy, Sudip Roy, Shiladitya Sengupta. A controlled affinity-guided ADC-linker (MAGNET) technology [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 751.
Abstract 755: Synthesis and evaluation of sugar alcohol based molecules for drug conjugation and delivery
Authors: Huang Yumei , Chen Shuyan , Sun Binyuan , Griffin Amanda , Sweet Nathanial , Feng Mingqian , Ho Mitchell
Published: August 2018

Hydrophilic linkers, which are available in different motifs, have been used as agents of drug delivery, as aqueous solubility enhancers for hydrophobic molecules, and as tethers or spacers in conjugation. Polyethylene glycol (PEG) is one of the most commonly used hydrophilic linkers and commercially available. Lower molecular weight (MW) heterobifunctional PEG linkers are the most frequently used linkers for linking hydrophobic compounds, whereas high MW polymers have been used to conjugate proteins, peptides, oligonucleotides, siRNA, and other therapeutic biopolymers. Here, we describe a new type of biomaterial based on sugar alcohols: AqueaTether™ (AqT™) molecules. Various AqT™ linkers with different lengths and end groups were synthesized and their hydrophilic nature and ability to enhance the water solubility of hydrophobic compounds compared to different commercial and PEG linkers. Various antibody drug conjugates (ADCs) with water soluble AqT™-drugs were prepared. An ADC made with AqT™-monomethyl auristatin E (MMAE) with only two sugar alcohol units attached and an average drug-to-antibody ratio (DAR) of 4 demonstrated significant improvements in minimizing the aggregation of antibodies and long-term stability during storage. Due to increased water solubility, AqT™ linkers also allow higher loading of drugs per antibody, enabling the use of less toxic drugs, potentially increasing the overall efficacy and safety profile of an ADC. For example, ADCs with average DARs of 8 and 15 have been made using AqT™-doxorubicin with only two sugar alcohol units attached. In peptide-based drug discovery, discrete high MW AqT™ linker is used to label peptide, resulting in an increased half-life in human serum. In summary, AqT™ molecules are by far the most hydrophilic and versatile linkers currently in development. AqT™ molecules represent a great tool for drug conjugation and delivery.

Citation Format: Yumei Huang, Shuyan Chen, Binyuan Sun, Amanda Griffin, Nathanial Sweet, Mingqian Feng, Mitchell Ho. Synthesis and evaluation of sugar alcohol based molecules for drug conjugation and delivery [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 755.
Abstract 78: p38 kinase is a negative regulator of tumorigenesis and recurrence after surgery in a mammary carcinoma model
Authors: Capobianco Carla S. , Sidabra Johanna E. , Gottardo Maria F. , Aguirre-Ghiso Julio A. , Alonso Daniel F. , Farina Hernan G.
Published: August 2018

The mitogen activated protein kinase (MAPK) p38 is a kinase involved in the response to different external stimuli, extremely diverse such as oxidative stress or growth factors. Its activation triggers different responses which include from promoting cell apoptosis or cell cycle arrest, to cell differentiation and the activation of survival pathways. Although the role of p38 in cancer is a well studied field, there are still multiple unanswered questions, given the large amount of evidence supporting both a tumorigenic but also a tumor suppressor function for p38 in cancer development and progression. In this study, the effects produced by p38 negative modulation using the chemical inhibitor SB203580 in different aspects of tumor biology are analyzed in vitro and in vivo. As a study model, F3II cell line was used, which is an aggressive murine mammary carcinoma. We found that p38 inhibition provokes contradictory effects in our mammary carcinoma model. On one hand, p38 inhibition provoked the reduction of cell viability and colony formation. On the other hand, SB203580 treatment increased cell adhesion and proliferation in matrix coated surfaces. In vivo we found that SB203580 treatment increases tumor aggressiveness. The shortened latency times, higher number of lung metastasis and larger local recurrences are a reflection of the aforementioned effect. Taking together, the results presented in this work position p38 as a tumor suppressor kinase, in the context of cells adapting to a new environment and developing the first stages of growth. P38 inhibition represented an advantage for cells newly inoculated in vivo. We consider that this phenotypic adaptation is probably a consequence of ERK activation and integrin α5 increased expression. Data presented here is of importance to show how determinant is the microenvironment in the responses elicited by the modulation of p38 kinase. We propose a differential role according to the environment conditions, which reflects the complexity of the pathway and the importance of the extracellular stimuli when evaluating the implications of treatment with p38 MAP kinase inhibitors.

Citation Format: Carla S. Capobianco, Johanna E. Sidabra, Maria F. Gottardo, Julio A. Aguirre-Ghiso, Daniel F. Alonso, Hernan G. Farina. p38 kinase is a negative regulator of tumorigenesis and recurrence after surgery in a mammary carcinoma model [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 78.
Abstract 81: Endogenous ADAMTS-13 regulates vasculogenic functions in glioblastoma cells
Authors: Tang Huiyuan , Lee Manfai , Kim Eun Ho , Bishop Daniel , Rodgers George M.
Published: August 2018

ADAMTS-13, a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13, is a zinc-containing metalloprotease that cleaves von Willebrand factor. Previous publications by our laboratory have shown that either endogenous or exogenous ADAMTS-13 may regulate angiogenesis in endothelial cells; for example, siRNA knockdown of endogenous endothelial cell ADAMTS-13 reduced angiogenic activities including cell migration, proliferation, and tube formation (Tang et al. Microvascular Res 2017; 113:85-70). Many tumor cells have the ability to develop a vascular phenotype, a process known as vasculogenic mimicry (VM). There is a multitude of evidence demonstrating that tumor cell-mediated VM may play a vital role in tumor development, independent of endothelial cell angiogenesis. For this study, we report that decreasing ADAMTS-13 levels inhibit vasculogenic functions in a glioblastoma cell line (LN-229), while increasing ADAMTS-13 levels had no effect. Incubating up to 30ng/ml of exogenous ADAMTS-13 did not promote cell proliferation and up to 200ng/ml did not change tube formation in LN-299 brain tumor cells. One possible explanation for this observation is that LN-299 brain tumor cells have almost twice the endogenous ADAMTS-13 expression than endothelial cells (~200pg/ml vs ~100pg/ml), so this cell line is not sensitive to exogenous ADAMTS-13. Using siRNA, we were able to successfully knockdown endogenous ADAMTS-13 in human brain tumor LN-229 cells. 50nM of ADAMTS-13 siRNA in a six-well plate inhibited HUVEC ADAMTS-13 expression levels by 75% after 48hr incubation, whereas control siRNA did not affect endogenous ADAMTS-13 levels. Additionally, expression of ADAMTS-1, a related family member of ADAMTS-13 was not affected by the knockdown. The effects of reduced endogenous ADAMTS-13 on glioblastoma vasculogenic functions were studied. Transfection of HUVEC with 50nM of ADAMTS-13 siRNA in a 24-well plate resulted in about 20% decrease in proliferation after 24hr and 48hr incubation. We demonstrated that decreased expression of endogenous ADAMTS-13 also affected vasculogenic mimicry as measured by glioblastoma cell tube formation using a Matrigel matrix method. The tube lengths, sizes and junction numbers of the ADAMTS-13 knockdown cells were all significantly lower compared to control cells by about 30-40%, respectively. Moreover, the expression of VEGF, a well-known regulator of angiogenesis, was significantly decreased by 25% after knockdown of endogenous LN-229 ADAMTS-13. Overall, these data suggest that endogenous ADAMTS-13 may regulate glioblastoma cell growth and function.

Citation Format: Huiyuan Tang, Manfai Lee, Eun Ho Kim, Daniel Bishop, George M. Rodgers. Endogenous ADAMTS-13 regulates vasculogenic functions in glioblastoma cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 81.
Abstract 813: Development of anti-Globo H ADC against cancer
Authors: Sun Wei-Ting , Chuang Shih-Hsien , Lee Chao-Pin , Chen Yi-Jen , Wei Win-Yin , Lee Ying-Shuan , Hsu Chuan-Lung , Nieh Yu-Chin , Wu Chia-Cheng
Published: August 2018

Globo H antigen is a hexasaccharide originally isolated as a ceramide-linked glycolipid from the human breast cancer cell line MCF-7. Globo H is also highly expressed in many other cancers such as colon cancer, ovarian cancer, gastric cancer, pancreatic cancer, lung cancer, and prostate cancer. DCBD16001 is an ADC from humanized anti-Globo H antibody DCBPR1101. DCBPR1101 and DCBD16001 both show good binding affinities against Globo H antigen. DCBD16001 also shows high cytotoxicity in Globo H overexpressing cell line MCF-7 and HCC-1428 and shows no cytotoxicity in Globo H negative cell line BT-474. DCBD16001 can internalize to target cell more than 50% within 4.0 hours. In vivo evaluation data indicates that DCBD16001 shows acceptable PK profiles and good efficacy. It shows nearly 80% tumor growth inhibition in HCC-1428 xenograft model. DCBD16001 is a candidate under pre-clinical development and expected to apply IND submission within two years.

Citation Format: Wei-Ting Sun, Shih-Hsien Chuang, Chao-Pin Lee, Yi-Jen Chen, Win-Yin Wei, Ying-Shuan Lee, Chuan-Lung Hsu, Yu-Chin Nieh, Chia-Cheng Wu. Development of anti-Globo H ADC against cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 813.
Abstract 831: Reproducible, mechanism of action-reflecting reporter based bioassays to enable drug development of biosimilars and biobetters
Authors: Somberg Richard L. , Moravec Rich , Li Dun , Paguio Aileen , Cong Mei
Published: August 2018

The demand for biosimilars and bioassays for biosimilars are increasing as the patent cliff approaches for many blockbuster biologics. Recently, the expanded approval of Actemra (Tocilizumab) to treat CAR T-cell-induced cytokine release syndrome (CRS) demonstrated the role of anti-IL-6 blocking drugs as critical for the treatment of serious diseases such as cancer and autoimmune diseases. Here we describe a portfolio of luciferase reporter-based bioassays to support the development and potency determination of biosimilar drugs targeting cytokines such as IL-2, IL-6, IL-12, IL-15, IL-12/23, IL-17, VEGF, RANK, Epo, IFNs, etc. The availability of quantitative, functional bioassays in Thaw-and-Use format provides the benefit of convenience, reproducibility, and transferability. We demonstrate these assays are able to measure relative potency for antibody biologics and detect potency changes for stressed antibody samples. In summary, the reporter-based bioassay portfolio for biosimilars provides a valuable tool for the development, stability testing, and potency determination in manufacture of biosimilars and biobetters.

Citation Format: Richard L. Somberg, Rich Moravec, Dun Li, Aileen Paguio, Mei Cong. Reproducible, mechanism of action-reflecting reporter based bioassays to enable drug development of biosimilars and biobetters [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 831.
Abstract 833: Anti-tumor efficacy of BA3021, a novel Conditionally Active Biologic (CAB) anti-ROR2 ADC
Authors: Sharp Leslie L. , Chang Cathy , Frey Gerhard , Wang Jing , Liu Haizhen , Xing Charles , Yalcin Safak , Walls Marlena , Ben Yong , Boyle William J. , Short Jay M.
Published: August 2018

ROR2 is a developmentally regulated member of the receptor tyrosine kinase orphan receptor (ROR) family and is a non-canonical receptor for selected Wnt family members. Many of the activities associated with ROR2 in development have also been implicated in cancer including cell migration and invasion. In many cancer types, expression of ROR2 correlates with advanced disease or poor prognosis. The high level of expression on the cancer cell surface has made it an attractive target for antibody-drug-conjugates (ADC). The Conditionally Active Biologics (CAB) technology is a patented, proprietary platform that selects antibodies that reversibly bind to target antigen in the context of diseased tissues, but not normal tissues, by taking advantage of the unique cancer microenvironment that is produced largely as a result of the Warburg effect. Using our CAB technology, we have identified anti-ROR2 selective Abs that reversibly bind to recombinant ROR2 and ROR2 expressing cells under conditions that are present in the tumor microenvironment, but not in normal tissues.

BA3021 is a CAB-ROR2-ADC. The pharmacological properties of BA3021 were characterized in a number of in vitro and in vivo pharmacology studies. BA3021 binds selectively to human and cyno ROR2 in conditions reflective of the tumor microenvironment, but has reduced binding under normal tissue conditions. BA3021 demonstrated ability to induce cytotoxicity of cell lines expressing ROR2 in vitro and inhibit tumor growth in LCLC-103H (lung), MDA-MB-436 (breast), HT1080 (sarcoma) and SK-MEL-5 (melanoma) human tumor xenografts and in selected sarcoma cancer patient derived xenograft models in vivo.

In conclusion, our data is consistent with our work on CAB-EGFR-ADC, CAB-AXL-ADC, CAB-PD-1 and other CAB programs and suggests that ADCs generated using the CAB technology provide biologics with increased therapeutic index. Specifically, the CAB-ROR2-ADC is an excellent candidate for evaluation as a treatment for human cancers that are ROR2 positive.

Citation Format: Leslie L. Sharp, Cathy Chang, Gerhard Frey, Jing Wang, Haizhen Liu, Charles Xing, Safak Yalcin, Marlena Walls, Yong Ben, William J. Boyle, Jay M. Short. Anti-tumor efficacy of BA3021, a novel Conditionally Active Biologic (CAB) anti-ROR2 ADC [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 833.
Abstract 845: Acute irradiation exposure induces long-term cardiac adverse effects in the spontaneously hypertensive rat
Authors: Rosen Elliot T. , Kryndushkin Dmitry , Aryal Baikuntha , Gonzalez Yanira , Chehab Leena , Dickey Jennifer , Mog Steven , Rao V Ashutosh
Published: August 2018

Radiation-induced heart disease (RIHD) presents a significant challenge in the oncology setting. For instance, patients receiving acute doses of irradiation to the thoracic cavity for Hodgkin's lymphoma or breast cancer are subject to an elevated risk of RIHD. Excessive oxidative stress, at least in part, is responsible for some of the tissue damage. The ability to monitor and mitigate the long-term cardiac effects of radiation exposure in these populations by modulating oxidative stress has the potential to lead to improved health outcomes. We utilized the spontaneously hypertensive rat (SHR), which has proven a good model for drug-induced cardiotoxicity, to evaluate irradiation-induced heart damage. SHRs were exposed to low, medium, or high doses of full-body irradiation. Necropsy was performed to collect serum and tissue samples at two and four weeks post-irradiation, as well as followed for one year. Four weeks following gamma irradiation, both males and females showed decreased heart mass and decreased whole body mass after exposure to medium and high doses of radiation and these decreases were sustained in the high dose groups after one year. Serum cardiac troponin I and T analysis revealed signs of cardiomyopathy in both the medium and high dose groups at early time points and this signal was sustained in some animals up to one year later. Echocardiography revealed functional changes in cardiac performance including an increase in left ventricular volume at diastole in males and a decrease in left ventricular mass. Low red blood cell count indicated sustained anemic conditions in both males and females receiving the highest dose of irradiation, yet males appeared to be more sensitive. Levels of pro-inflammatory IL-6 were elevated at four weeks in males receiving the high dose. Finally, multiple animals receiving radiation developed spontaneous tumors after one year. We are currently investigating the oxidative stress-mediated molecular mechanisms behind the radiation-induced cardiac damage.

Citation Format: Elliot T. Rosen, Dmitry Kryndushkin, Baikuntha Aryal, Yanira Gonzalez, Leena Chehab, Jennifer Dickey, Steven Mog, V Ashutosh Rao. Acute irradiation exposure induces long-term cardiac adverse effects in the spontaneously hypertensive rat [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 845.
Abstract 856: Selection of radiosensitizers based on HRAS mutation in bladder cancer
Authors: Fisher Michael M. , Swick Adam D. , Nickel Kwangok P. , Kimple Randall J.
Published: August 2018

Purpose/Objective(s): The ability of activated HRAS to promote radiation resistance and predict for sensitivity to potential radiosensitizers was tested in a bladder cancer model system.

Materials/Methods: Mutations in HRAS, KRAS, and NRAS were analyzed using cBioPortal in a bladder cancer cohort (TCGA). We employed a panel of urothelial carcinoma cell lines-T24 (HRASG12V), J82 and 5637 (RASWT). Cell growth and survival was tested with colony formation and proliferation assays. Radiation survival was assessed by clonogenic survival assay. Immunoblots were used to confirm mutant HRAS expression, and target activation/knockdown in overexpression and knockdown studies. Radiosensitization of mutant-HRAS bladder cancer was tested using a flank cell line xenograft model in nude mice.

Results: Approximately 10% of bladder cancers feature alterations in one of three RAS genes; mutations in HRAS comprise greater than 50% of these. An HRAS activating (G12V) mutation was detected in T24. Consistent with known roles for activated RAS, T24 is relatively insensitive to both cetuximab and radiation. Using both in vivo and in vitro studies, cetuximab exhibited no radiosensitization of T24. Treatment with cetuximab lowered AKT, but not ERK activation. Direct inhibition of the MEK/ERK or PI3K/MTOR pathway by selumetinib or BEZ235, respectively, decreased target protein activation and resulted in significant growth inhibition compared to control (p<0.05). Treatment with either selumetinib or BEZ235 radiosensitized HRASG12V expressing cells (SER 1.3-1.8), but had more modest effects on cells with wild-type HRAS. siRNA knockdown of HRAS radiosensitized T24, but not J82 or 5637 cells relative to non-targeting control. The combination of selumetinib and radiation therapy delayed the growth of T24 tumors in vivo.

Conclusions: Over 10% of bladder cancers feature alterations in the RAS family of genes. These mutations can lead to resistance to cetuximab, either as a single treatment or as a radiosensitizer. Inhibition of downstream MEK/ERK and PI3K/MTOR pathways can radiosensitize tumors with activating mutations in HRAS. Identification of additional mutation/drug combinations that result in radiosensitization may be valuable to advance the design of personalized radiation therapy.

Citation Format: Michael M. Fisher, Adam D. Swick, Kwangok P. Nickel, Randall J. Kimple. Selection of radiosensitizers based on HRAS mutation in bladder cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 856.
Abstract 860: Experimental alpha-radioimmunotherapy for liver metastasis of gastric cancer
Authors: Li Huizi Keiko , Hasegawa Sumitaka
Published: August 2018

Gastric cancer (GC) is one of the leading causes of cancer-related death worldwide. Early stage of GC is curable by surgical therapy or endoscopic surgery. However, previous studies reported that 35% of patients is present with evidence of distant metastasis at the time of diagnosis of GC. Metastatic GC is fetal and the patients with metastatic GC has extremely poor prognosis because current therapeutic approaches to metastatic GC are still limited. Therefore, the development of new therapeutic options has been eagerly awaited. Liver metastasis of GC (LMGC) is often observed during GC progression. It has been shown that 4-14% of the patients has LMGC. It is believed that LMGC is occurred by blood-borne metastasis of GC cells via blood stream. A previous study reported that approximately 70% of LMGC was positive for human epidermal growth factor receptor 2 (HER2). Therefore, HER2 may be a reliable therapeutic target for LMGC. Alpha-particle radioimmunotherapy (alpha-RIT) is an emerging new therapy, in which radioisotopes emitting cytotoxic alpha-particle radiation are delivered to target cancer cells to kill the cells by target-specific antibody. Among alpha-particle emitters, astatine-211 (At-211) is a promising emitter because it emits highly cytotoxic alpha-particles during its decay process with a half-life of 7.2 hours. The aim of this study is to evaluate the therapeutic efficacy and toxicity of At-211-labled anti-HER2 antibody trastuzumab ([At-211]trastuzumab) in a preclinical mouse model of HER2-positive LMGC. We established a mouse model of LMGC by injection of luciferase-labelled HER2-positive human metastatic GC cells (NCI-N87) into splenic vein of severe combined immunodeficiency mouse. Biodistribution studies revealed that the maximum tumor uptake of [At-211]trastuzumab was about 12% of injected dose per tissue gram 24 hours after injection. In experimental therapies, a systemic injection of [At-211]trastuzumab (1 MBq) significantly reduced a tumor burden in the liver and prolonged the survival. Transient but recoverable leukocytopenia was observed in mice received 1 MBq of [At-211]trastuzumab at 5-7 days after injection. No body weight loss was found during the observation period. In this study, we provides a preclinical evidence that alpha-RIT using [At-211]trastuzumab may be a new therapeutic option against LMGC.

Citation Format: Huizi Keiko Li, Sumitaka Hasegawa. Experimental alpha-radioimmunotherapy for liver metastasis of gastric cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 860.
Abstract 87: Nuclear localization of p70 S6 kinase in ovarian cancer
Authors: ZHOU Jing , TO Sally K. , WONG Alice S.
Published: August 2018

Ovarian cancer is highly metastatic with a poor prognosis. The p70 S6 kinase (p70S6K) is a downstream effector of the phosphatidylinositol-3 kinase/Akt pathway that is frequently activated in ovarian cancer. Constitutive activation of p70S6K is significantly more often in malignant ovarian tumors than in normal or benign tissues, suggesting a role for p70S6K in tumor development and progression. In addition to its well-established role in cell growth and survival, we showed for the first time that p70S6K plays a pivotal role in other aspects of tumor progression such as metastasis. Here, we further showed that this was associated with the nuclear localization of p70S6K. Treatment of cells with the CRM1 inhibitor, leptomycin B, retained p70S6K in the nucleus. Growth factor stimuli led to p70S6K phosphorylation and triggered nuclear translocation of p70S6K. The phosphorylation was sensitive to p70S6K inhibitors. We further identified a potential region that was important in its nuclear localization. Expression of nuclear localization signal-p70S6K enhanced tumor cell migration and invasion when compared to non-targeted p70S6K. Our findings identify a region responsible for the nuclear entry of p70S6K and demonstrate a functional significance of nuclear p70S6K in tumor progression (This work is supported by RGC grant 17103417).

Citation Format: Jing ZHOU, Sally K. TO, Alice S. WONG. Nuclear localization of p70 S6 kinase in ovarian cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 87.
Abstract 891: A novel quinazolin-4(3H)-one/Schiff base hybrid phosphodiesterase 4 inhibitor as a potential therapeutic agent for leukemia
Authors: Richard Alexander , Abdel-Rahman Hamdy M. , Kim Jung Hyun , Vukadin Lana , Piazza Gary A. , Ahn Eun-Young E.
Published: August 2018

Cyclic adenosine monophosphate (cAMP) is a secondary messenger that regulates cell proliferation, differentiation, and apoptosis. Phosphodiesterases (PDEs) are enzymes that catabolize cyclic nucleotides to relay cellular signals. Among them, PDE4 is a cAMP-specific PDE isozyme family and several PDE4 inhibitors have been developed to treat a diverse group of diseases, such as asthma and chronic obstructive pulmonary disease. Although PDE4 inhibitors have been demonstrated to induce cell death in solid tumors, their therapeutic potential in treatment of hematopoietic malignancies has not been well studied. Our analysis on the expression pattern of PDE family demonstrated that PDE4B is abundantly expressed in blood cancers compared to other solid tumors, implicating PDE4 as a potential therapeutic target for leukemia. N-acylhydrazone and nitraquazone are potent PDE inhibitors that are structurally unrelated to rolipram, a prototypical PDE4 inhibitor. To develop novel PDE4 inhibitors with increased scaffold rigidity, we hybridized N-acylhydrazone with Nitraquazone, and designed a series of quinazolin-4(3H)-one/schiff base hybrid compounds. Among those, compound 23 (CPD23) showed the best activity in PDE4B inhibition, and was selected for further studies. Our results showed that CPD23 treatment leads to growth inhibition and cell cycle arrest of several human leukemia cell lines. Since cAMP is a well-studied secondary messenger for megakaryopoesis and apoptosis, we continued to elucidate CPD23's mechanism of action in several megakaryoblastic leukemia cell lines. While other well-known PDE4 inhibitors, such as rolipram, did not show any effect in cell viability, CPD23 significantly decreases the viability of megakaryoblastic cell lines. Further studies on molecular actions revealed that CPD23 caused double-stranded DNA breaks, which was detected by increased ϒH2AX levels. Quantitative RT-PCR experiments also demonstrated that CPD23 induces transcriptional activation of megakaryocytic differentiation markers, such as CD61, in selective cell lines. Taken together, our study shows that CPD23, synthesized as a quinazolin-4(3H)-one/schiff base hybrid PDE4 inhibitor, decreases proliferation, induces double-stranded DNA breaks, and differentiation in megakaryoblastic leukemia cell lines. Further studies will enhance our knowledge on detailed molecular actions of CPD23 and its therapeutic value for leukemia.

Citation Format: Alexander Richard, Hamdy M. Abdel-Rahman, Jung Hyun Kim, Lana Vukadin, Gary A. Piazza, Eun-Young E. Ahn. A novel quinazolin-4(3H)-one/Schiff base hybrid phosphodiesterase 4 inhibitor as a potential therapeutic agent for leukemia [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 891.
Abstract 901: Antibody-mediated blockade of annexin A3 (ANXA3) synergistically enhances the efficacy of sorafenib and regorafenib for hepatocellular carcinoma
Authors: Tong Man , Che Noelia , Zhou Lei , Kau Phillis W. , Luk Steve T. , Chen Xin , Ding Jin , Lee Terence K. , Ma Stephanie
Published: August 2018

Advanced hepatocellular carcinoma (HCC) is a lethal malignancy with limited treatment options. Sorafenib is the only FDA approved first-line targeted drug for advanced HCC, but its effect on patients' survival gain is limited and patients ultimately present disease progression. Molecular mechanism underlying acquired resistance are still far from being well understood. A better understanding of causes of sorafenib resistance, enhancing the efficacy of sorafenib and finding a reliable predictive biomarker are crucial to achieve efficient control of HCC. In this study, we uncovered a role of annexin A3 (ANXA3) in conferring ability of HCC cells to resist sorafenib. ANXA3 was found highly enriched in sorafenib-resistant HCC cells and patient-derived xenografts. Mechanistically, we found overexpression of ANXA3 in sorafenib-resistant HCC cells to suppress PKCδ/p38 associated apoptosis and activate autophagy for cell survival. ANXA3 expression correlated positively with LC3B, an indicator of autophagy induction, in HCC specimens and was associated with a worst overall survival in HCC patients who went on to receive sorafenib treatment. Anti-ANXA3 therapy, alone or combined with sorafenib and regorafenib, the standard of care for advanced HCC, impaired tumor growth in vivo and significantly increased survival. In sum, we found anti-ANXA3 therapy to exhibit abilities to reduce tumor growth and sensitize HCC cells to sorafenib and regorafenib treatment via suppressing autophagy and activating apoptosis. Inhibition of ANXA3 would benefit a subset of patients after sorafenib progression. ANXA3 can also serve as a useful predictive biomarker for patient response to sorafenib treatment.

Citation Format: Man Tong, Noelia Che, Lei Zhou, Phillis W. Kau, Steve T. Luk, Xin Chen, Jin Ding, Terence K. Lee, Stephanie Ma. Antibody-mediated blockade of annexin A3 (ANXA3) synergistically enhances the efficacy of sorafenib and regorafenib for hepatocellular carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 901.
Abstract 911: Targeting the mutant KRAS/BRAF-induced enhancer as an approach to overcome resistance to 5-fluorouracil-based chemotherapy in colorectal cancer
Authors: Wu Rentian , Nie Qian , Kubica Phillip A. , Wang Zhiquan , Shrestha Shikshya , Trogstad-Isaacson Colbren S. , Jerde Calvin R. , Tapper Erin E. , Bouchonville Kelly J. , Offer Steven M. , Diasio Robert B.
Published: August 2018

Colorectal cancer (CRC) is the third most common cancer and is expected to cause approximately 50,000 deaths in the US in 2017. The antimetabolite 5-fluorouracil (5-FU) is the cornerstone of first-line adjuvant chemotherapy regimens for CRC. Resistance to 5-FU-based chemotherapies develops over time and is the greatest obstacle to effective management in this disease. However, the resistance mechanisms of 5-FU are largely unknown. Approximately 50% of the CRC cases have activating mutations in KRAS or BRAF. Based on recent clinical data, it is now appreciated that KRAS/BRAF mutations are associated with worse survival in 5-FU-based chemotherapies for CRC. Therefore, there is an urgent unmet need for improved therapeutic options to treat mutant KRAS/BRAF tumors. We analyzed the differential activation status of enhancers in KRAS/BRAF mutant and wildtype CRC cell lines. Enhancers that associated with genes regulating pyrimidine metabolism were significantly enriched in KRAS/BRAF mutant CRC cells. Among them, the differential activation of an enhancer located ~400kb upstream of the DPYD promoter was most significant. By using CRISPR-dCas9 system, specifically targeting of p300 to the enhancer significantly increased DPYD expression, and Ezh2 significantly decreased expression. Knockout (KO) of this enhancer resulted in reductions in DPD expression and increased resistance to 5-FU. In mouse xenograft studies, enhancer-KO cells responded to doses of 5-FU that were otherwise ineffective against control cells. Treating KRAS mutant CRC cells with CBP30, H3K27 acetyl-transferase inhibitor, significantly reduced DPYD expression. Synergistic interactions was identified between CBP30 and 5-FU. Finally, mouse xenograft studies strongly suggest that inhibition of H3K27ac may significantly improve 5-FU effectiveness against KRAS mutant tumors. In summary, the present studies advance our understanding of how mutant KRAS/BRAF epigenetically regulates DPYD expression and results in 5-FU resistance in CRC. We showed that clinical treatment of CRC might be significantly improved by the development of future pharmacologic approaches targeting enhancers that are activated by mutant KRAS/BRAF.

Citation Format: Rentian Wu, Qian Nie, Phillip A. Kubica, Zhiquan Wang, Shikshya Shrestha, Colbren S. Trogstad-Isaacson, Calvin R. Jerde, Erin E. Tapper, Kelly J. Bouchonville, Steven M. Offer, Robert B. Diasio. Targeting the mutant KRAS/BRAF-induced enhancer as an approach to overcome resistance to 5-fluorouracil-based chemotherapy in colorectal cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 911.
Abstract 949: Progesterone receptor/IRS-1 cooperation promotes stem cell outgrowth and endocrine resistance in estrogen receptor-positive luminal breast cancer
Authors: Dwyer Amy R. , Sachdev Deepali , Lange Carol A.
Published: August 2018

Luminal breast cancers account for ~75% of all cases and while adjuvant hormone therapy targeting ERα has significantly improved overall survival for patients with ER+ tumors, acquired resistance remains a major clinical problem. Tamoxifen-resistant (TamR) breast cancer models show loss of IGF1R concomitant with increased insulin-induced growth, underpinned by insulin receptor (InsR) compensation for IGF1R loss. PR (gene name PGR) is an estrogen-regulated target gene whose expression is used as a clinical marker of ER activity. However, its de novo relevance to breast cancer is unclear. We have shown previously that post-translational modifications create unique PR species whose altered behavior drives an endocrine-resistant gene signature, in part by crosstalk with the IGFR pathway. We propose that phospho-PR target gene selectivity is mediated by cooperation between PR-B and InsR/IGF1R pathway components. Herein we show that phospho-PR-expressing T47D cells lose expression of IGF1R compared to control cells expressing WT PR-B. Furthermore, expression of the adapter protein IRS-1 requires PRB expression and these IRS-1+ cells were more sensitive to insulin in anchorage-dependent growth assays. Phospho-PR T47D cells exhibit increased ALDH+ and CD24-/CD44+ tumorsphere formation compared to wt PRB-expressing cells. Inhibitors targeting IRS-1 and InsR were used to test their requirement for tumorsphere growth and, surprisingly, IRS-1 perturbation reduced phospho-PRB but not wt PRB tumorsphere growth. Interestingly, IRS-1 replaces IGF1R in phospho-PRB-containing transcriptional complexes that are recruited to the CTSD promoter, which we previously identified as a phospho-PR target gene. Finally, breast cancer cells expressing phospho-PR species exhibited tamoxifen-resistant growth. Collectively our data suggest that phospho-PRB cooperates with IRS-1 downstream of the Ins/IGF1R system to promote outgrowth of endocrine-resistant cells that include ALDH+ stem-like cells capable of forming secondary tumorspheres in vitro. Targeting phospho-PR species in addition to the signaling components of PR-complexes may provide a means to block emergence of endocrine-resistant cancer cells during breast cancer progression.

Citation Format: Amy R. Dwyer, Deepali Sachdev, Carol A. Lange. Progesterone receptor/IRS-1 cooperation promotes stem cell outgrowth and endocrine resistance in estrogen receptor-positive luminal breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 949.