bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 682: The mechanism of PI3Kα activation by SH2 release
Authors: Zhang Mingzhen , Jang Hyunbum , Nussinov Ruth
Published: August 2018

Phosphoinositide 3-kinase α (PI3Kα) is a ubiquitous kinase mediating signaling cascades important for cell survival, proliferation and protein synthesis. It phosphorylates PIP2 to PIP3, to which downstream Akt kinase binds to execute singling. PI3Kα dysfunction has been extensively implicated in cancers. The kinase activity of PI3Kα is controlled by the interactions between its catalytic p110 and regulatory p85 subunits. The interactions of the SH2 domains in the p85 subunit, particularly nSH2, with p110 are key factors in PI3Kα inhibition. Release of the SH2 domains from the p110 subunit, is promoted by factors including phosphotyrosine peptides (RTK), calmodulin (CaM), and oncogenic mutations, thereby activating PI3Kα. Our recent data show that both phosphorylated and unphosphorylated CaMs are capable of binding to the SH2 domains, nSH2 and cSH2, thus promoting the PI3K activation. Despite numerous seminal publications over the past two decades, the mechanism of PI3Kα activation is still a mystery. The large distance between the PIP2 binding sites and the ATP pocket in the crystal structure suggests that the solved PI3Kα structure represents the inactive conformation. What is the activated conformation of PI3Kα, and how PI3Kα switches from the inactive to the active conformation in response to stimulus are the significant mechanistic questions. We employ the large-scale molecular dynamics (MD) simulations to visualize the PI3Kα activation stimulated by the release of SH2 domains in the p85 subunit at the atomic resolution. Our trajectories show that release of the nSH2 domain initiates a “switch-like” conformational change of the iSH2 domain, extracting the ATP from its pocket to the PIP2 binding sites, eventually leading to an activated conformation. This dynamic process is initiated by the break of salt-bridges between iSH2 and helical domains induced by the nSH2 release, and further facilitated by the various residues in activation loop of p110 subunit including His-917, Lys-802 and Lys-776 and in iSH2 of p85 subunit including Arg-461 and Arg-465. The release of the cSH2 domain in PI3Kα has a minor effect. This work, which for the first time uncovers the mechanism of PI3Kα activation at atomic resolution, is expected to promote cancer drug design from a mechanistic dynamic standpoint view. Funded by Frederick National Laboratory for Cancer Research, National Institutes of Health, under contract HHSN261200800001E.

Citation Format: Mingzhen Zhang, Hyunbum Jang, Ruth Nussinov. The mechanism of PI3Kα activation by SH2 release [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 682.
Abstract 692: Systemic inflammation and survival in colon and rectal cancer patients: Results from the ColoCare Study
Authors: Ose Jennifer
Published: August 2018

BACKGROUND

Systemic inflammation is an established risk marker for colorectal cancer that may also predict survival. We investigated associations between systemic inflammation and overall survival in a prospectively followed cohort of colorectal cancer patients.

METHODS

Pre-operatively collected serum samples from n=228 newly diagnosed colorectal cancer patients (stage I-IV) from the ColoCare Study were utilized to measure CRP, SAA, IL-6, IL-8, sICAM-1 and sVCAM-1 (Meso Scale Discovery platform). We used Cox proportional hazard models to investigate associations of biomarkers with overall survival after 24 months follow-up overall, and in analyses stratified by colon (n=92) and rectal tumors (n=136). Analyses were adjusted for age, sex, tumor stage and neo-adjuvant therapy (y/n).

RESULTS

After 24 months follow-up n=45 patients (20%) were deceased. CRP was significantly associated with increased risk of death in colon (HR:1.27; 95% CI: 1.03-1.57; pValue=0.02) but not rectal cancer (HR:1.06; 95% CI: 0.87-1.29; pValue=0.55). A doubling of circulating sICAM and sVCAM concentrations was significantly associated with increased risk of death in colorectal cancer (sICAM: HR:2.82; 95% CI: 1.57-5.05; pValue=0.0005; sVCAM: HR:3.70; 95% CI: 1.93-7.10; pValue<0.0001). For both biomarkers we observed stronger associations in rectal compared to colon cancer (e.g., sVCAM: rectal cancer (HR:8.13; 95% CI: 3.13-21.11; pValue<0.0001); colon cancer (HR:1.42; 95% CI: 0.68-2.98; pValue=0.35). Circulating IL-6 and IL-8 were not associated with increased risk of death in colon and/or rectal cancer.

CONCLUSIONS

Inflammatory biomarkers are significantly associated with increased risk of death in colorectal cancer patients. Our data suggest that the role of inflammation in disease progression may be particularly strong relevant in rectal cancer.

Keywords: colorectal cancer; inflammation, biomarkers, overall survival,

Citation Format: Jennifer Ose. Systemic inflammation and survival in colon and rectal cancer patients: Results from the ColoCare Study [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 692.
Abstract 699: Pd-l1 gene alterations identify a subset of diffuse large B cell lymphoma harboring a T cell inflamed phenotype
Authors: Kline Justin Paul , Godfrey James , Tumuluru Sravya , Venkataraman Girish , Bao Riyue , Smith Sonali M.
Published: August 2018

Programmed death – ligand 1 (PD-L1) expression on malignant cells is a dominant immune escape mechanism across a variety of human cancers, and classically occurs as an adaptive response to the presence of activated T cells and interferon gamma (IFN-γ) in the tumor environment. Interestingly, a unique genetic mechanism underlying PD-L1 up-regulation has been described in classical Hodgkin lymphoma (cHL) and in uncommon variants of diffuse large B cell lymphoma (DLBCL), in which the chromosomal region (9p24.1) encoding the PD-1 ligands is highly amplified. While chromosome 9p24.1 copy number alterations (CNA) are ubiquitous in cHL, which is exquisitely sensitive to PD-1 blockade therapy, they also occur in DLBCL, albeit with a lower incidence. Here, FISH was utilized to identify DLBCLs harboring pd-l1 CNA, thereby enabling a characterization the immunogenomic landscape of these lymphomas compared to those lacking pd-l1 CNA. Among 76 DLBCLs analyzed, 25% harbored pd-l1 CNA (12 copy gain, 6 amplified, 1 translocation). Pd-l1 CNA were highly enriched among DLBCLs with an activated B cell (ABC) phenotype (75%). PD-L1 cell surface expression was strikingly enhanced in DLBCLs with pd-l1 CNA versus those without, as assessed by PD-L1 H score. Furthermore, pd-l1 CNA were associated with a pronounced infiltration of DLBCLs by T cells with a restricted T cell receptor (TCR) – beta (β) repertoire, suggesting that lymphoma antigen-specific T cells had expanded in these samples. RNA-sequencing of pd-l1 gene-altered versus non-altered DLBCLs revealed differential expression of pd-l1, as well as genes involved in T cell and cytokine signaling in the former, indicating that pd-l1 gene-amplified DLBCLs have been subjected to host immune surveillance. Lastly, whole exome sequencing (WES) of pd-l1 gene altered versus non-altered DLBCLs to identify potential differences in mutational loads and profiles is ongoing. Collectively, our results indicate that pd-l1 CNA identify a unique biological subset of DLBCL that has activated an endogenous anti-lymphoma immune response, and that may be more likely to respond to checkpoint blockade therapy with anti-PD-1 antibodies. We propose that a straightforward FISH analysis for pd-l1 gene amplification may be useful as a predictive biomarker for immunotherapy responsiveness in DLBCL.

Citation Format: Justin Paul Kline, James Godfrey, Sravya Tumuluru, Girish Venkataraman, Riyue Bao, Sonali M. Smith. Pd-l1 gene alterations identify a subset of diffuse large B cell lymphoma harboring a T cell inflamed phenotype [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 699.
Abstract 702: IMLEC: A population of innate myelolymphoblastoid effector cell expanded by inactivation of mTOR complex 1
Authors: Tang Fei , Zhang Peng , Ye Peiying , Lazarski Christopher A. , Wu Qi , Bergin Ingrid L. , Bender Timothy P. , Hall Michael N. , Cui Ya , Zhang Liguo , Jiang Taijiao , Liu Yang , Zheng Pan
Published: August 2018

Adaptive autoimmunity is restrained by controlling population sizes and pathogenicity of harmful clones, while innate destruction is controlled at effector phase. We report here that deletion of Rptor in hematopoietic stem/progenitor cells causes self-destructive innate immunity by massively increasing the population of previously uncharacterized innate myelolymphoblastoid effector cells (IMLECs). IMLECs are CD3-B220-NK1.1-Ter119- CD11clow/-CD115-F4/80low/-Gr-1- CD11b+, but surprisingly express high levels of PD-L1. Although they morphologically resemble lymphocytes and actively produce transcripts from Immunoglobulin loci, IMLECs have non-rearranged Ig loci, are phenotypically distinguishable from all known lymphocytes, and have a gene signature that bridges lymphoid and myeloid leukocytes. Rptor deletion unleashes differentiation of IMLECs from common myeloid progenitor cells by reducing expression of Myb. Importantly, IMLECs broadly overexpress pattern-recognition receptors and their expansion causes systemic inflammation in response to Toll-like receptor ligands. Our data unveil a novel leukocyte population and an unrecognized role of Raptor/mTORC1 in innate immune tolerance. Moreover, since IMLECs constitutively express high levels of PD-L1, it is interesting to investigate their functions in cancer immunotherapy.

Citation Format: Fei Tang, Peng Zhang, Peiying Ye, Christopher A. Lazarski, Qi Wu, Ingrid L. Bergin, Timothy P. Bender, Michael N. Hall, Ya Cui, Liguo Zhang, Taijiao Jiang, Yang Liu, Pan Zheng. IMLEC: A population of innate myelolymphoblastoid effector cell expanded by inactivation of mTOR complex 1 [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 702.
Abstract 727: A novel rMVA combination immunotherapy triggers potent innate and adaptive immune responses against established tumors
Authors: Medina-Echeverz Jose , Hinterberger Maria , Testori Marco , Geiger Marlene , Giessel Raphael , Chaplin Paul , Hochrein Hubertus , Lauterbach Henning
Published: August 2018

Virus-based vaccines and appropriate costimulation enhance potent antigen-specific T cell immunity against cancer. However, the tumor microenvironment exerts intrinsic and extrinsic mechanisms to evade tumor destruction. In the present study we exploit both innate and adaptive immune responses triggered by a novel recombinant modified vaccinia virus Ankara (rMVA) encoding costimulatory CD40L against solid tumors in combination regimes to overcome tumor-induced resistance to immunotherapy. Therapeutic treatment with rMVA-CD40L resulted in strong antitumor effects in unrelated established tumor models. Tumor infiltration was composed of non-exhausted, antigen-specific CD8+ T cells with proliferative capacity after rMVA-CD40L immunization. Strikingly, this antitumor effect was not entirely dependent on cross-presenting CD8α+ DC -induced CD8+ T cell expansion, as experiments with MVA encoding for T. gondii profilin (TLR11 ligand) and using Batf3-/- tumor bearers depicted. Indeed, rMVA-CD40L-induced tumor control did not depend on cytosolic DNA sensor STING. Interestingly, rMVA-CD40L induced strong NK cell activation and thereby potent Antibody Dependent Cell Cytotoxicity (ADCC) against Tumor-Associated Antigen (TAA) targeting antibodies. Hence, the combination of TAA targeting antibodies and rMVA-CD40L resulted in increased therapeutic antitumor efficacy. We describe a novel and translationally relevant therapeutic synergy between viral vaccination and CD40L costimulation. We connect CD40 ligation to cross-presenting CD8α+ DC -mediated expansion of non-exhausted CD8+ T cells in the tumor microenvironment. Taking advantage from intrinsic MVA-induced NK cell activation and further improved NK cell function by CD40 ligation, we show strengthened antitumor immune responses when both rMVA-CD40L-induced innate and adaptive immune mechanisms are exploited by combining immunotherapeutic regimes. This finding has a direct potential impact in clinical trials where TAA targeting antibodies are currently under evaluation.

Citation Format: Jose Medina-Echeverz, Maria Hinterberger, Marco Testori, Marlene Geiger, Raphael Giessel, Paul Chaplin, Hubertus Hochrein, Henning Lauterbach. A novel rMVA combination immunotherapy triggers potent innate and adaptive immune responses against established tumors [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 727.
Abstract 734: Thienoindoles: New highly promising agents for antibody-drug conjugates generation
Authors: Caruso Michele , Gasparri Fabio , Valsasina Barbara , Albanese Clara , Beria Italo , Candiani Ilaria , Ciomei Marina , Colombo Nicoletta , Cribioli Sabrina , Cucchi Ulisse , Felder Eduard , Fraietta Ivan , Galvani Arturo , Isacchi Antonella , Marsiglio Aurelio , Orsini Paolo , Perego Rita , Rizzi Simona , Tomasi Attilio , Troiani Sonia , Visco Carlo , Donati Daniele
Published: August 2018

Thienoindoles are a new proprietary class of highly potent DNA minor groove alkylating agents.

This class is characterized by a fused thiophene ring whose intrinsic electron-withdrawing character provides a nearly optimal increase in stability and potency of alkylating subunits. Furthermore, the presence of a solubilizing moiety on the minor groove portion provides compounds with physicochemical properties highly compatible with deployment as antibody payloads.

Extensive optimization of this class has led to the identification of the highly potent toxin NMS-P528 with sub-nanomolar IC50 in proliferation assay across a large panel of tumor cell lines.

NMS-P945, a drug-linker generated from NMS-P528, is highly suited for conjugation with targeted antibodies, consistently yielding ADCs with favorable drug-antibody ratios in the absence of significant antibody aggregation and with full maintenance of antigen binding capability.

Proof of concept efficacy and mechanism of action studies were performed using NMS-P945 conjugated with trastuzumab, observing for the resulting conjugate excellent in vitro target-directed cytotoxicity in HER2-positive vs. negative cancer cell lines. In animal efficacy studies against HER2-positive human breast cancer tumors, trastuzumab-NMS-P945 ADC administration yielded complete tumor regression with no effects on body weight gain, while unarmed trastuzumab and armed control antibody showed little and no effect, respectively. PK data indicated long plasma half-life of our novel ADCs in the monkey. Promising results were also obtained with a range of different antibody/antigen systems, e.g. with an antibody directed to the ALK receptor tyrosine kinase.

Extensive process research has been completed for the production of NMS-P528 and NMS-P945, resulting in an efficient stereoselective method for the preparation of GMP materials on the 100g scale and both products are proposed as a licensing opportunity for conjugation with tumor-targeting antibodies.

Citation Format: Michele Caruso, Fabio Gasparri, Barbara Valsasina, Clara Albanese, Italo Beria, Ilaria Candiani, Marina Ciomei, Nicoletta Colombo, Sabrina Cribioli, Ulisse Cucchi, Eduard Felder, Ivan Fraietta, Arturo Galvani, Antonella Isacchi, Aurelio Marsiglio, Paolo Orsini, Rita Perego, Simona Rizzi, Attilio Tomasi, Sonia Troiani, Carlo Visco, Daniele Donati. Thienoindoles: New highly promising agents for antibody-drug conjugates generation [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 734.
Abstract 741: Targeting trastuzumab and T-DM-1 resistant breast cancer cells with EV20/MMAF, an antibody drug-conjugate against HER3
Authors: Sala Gianluca , Gandullo Lucia , Capone Emily , Diaz-Rodriguez Maria Elena , D'Agostino Daniela , Laurenzi Vincenzo De , Sauniere Jean-Frederic , Iacobelli Stefano , Pandiella Atanasio
Published: August 2018

Trastuzumab and its derivative Trastuzumab-emtansine (T-DM1) are drugs approved to treat HER-2+ tumors. Despite the impressive clinical efficacy observed in many patients, intrinsic and acquired resistance to both drugs has emerged as a challenge. The HER-3 receptor is emerging as an attractive molecule in therapeutics because of its overexpression across many human cancers and because of its role in resistance to certain anticancer drugs. We recently showed that the EV20 humanized anti-HER-3 antibody has the ability of selectively and efficiently deliver the plant toxin Saporin to tumor cells. Here, we describe the antitumor activity of a novel ADC derivative of EV20 coupled to the cytotoxic drug monomethyl auristatin F (MMAF). This HER-3/ADC (EV20/MMAF) demonstrated a powerful and target-dependent killing activity in a panel of HER2+ breast cancer cells, including those resistant to trastuzumab and T-DM1 with an IC50 in the pico/nanomolar range.

EV20/MMAF mediated potent antitumor activity in mice bearing trastuzumab resistant xenograft models. Notably, we found that the novel conjugate was well tolerated and caused tumor shrinkage in 100% of tumor-bearing mice. In summary, these findings open the possibility to use EV20/MMAF as a novel ADC targeting HER-3 and support its clinical development for malignancies, such as HER-2+ breast cancer, in which HER-3 is frequently overexpressed.

Citation Format: Gianluca Sala, Lucia Gandullo, Emily Capone, Maria Elena Diaz-Rodriguez, Daniela D'Agostino, Vincenzo De Laurenzi, Jean-Frederic Sauniere, Stefano Iacobelli, Atanasio Pandiella. Targeting trastuzumab and T-DM-1 resistant breast cancer cells with EV20/MMAF, an antibody drug-conjugate against HER3 [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 741.
Abstract 747: A new class of DNA alkylating indolino-benzodiazepine agents (BIAs) linked with a DNA binding moiety for use with antibody-drug conjugates (ADCs)
Authors: Miller Michael L. , Reid Emily E. , Archer Katie E. , Shizuka Manami , McShea Molly A. , Maloney Erin K. , Ab Olga , Lanieri Leanne , Wilhelm Alan J. , Ponte Jose F. , Yoder Nicholas C. , Chari Ravi V.
Published: August 2018

We have previously disclosed antibody-drug conjugates (ADCs) that incorporate our highly potent novel DNA alkylating indolino-benzodiazepine (termed IGN) pseudo dimer. ADCs of these DNA alkylating IGNs were found preclinically to demonstrate better tolerability and an improved overall therapeutic index (TI) compared with those of DNA crosslinking IGNs (Miller, et al., AACR 2017 #53). In our ongoing effort to further explore DNA alkylating effector molecules for ADCs, we disclose here a new class of IGNs (termed BIAs) in which one IGN monomer subunit is connected to a bis-aryl moiety with affinity for the DNA binding pocket. Our initial structure activity relationship (SAR) studies around a series of BIAs identified a set of scaffolds that met our requirement for high in vitro potency. These scaffolds were subsequently modified to incorporate functionalities that allow linkage to an antibody using various linker chemistries. These linkable BIAs displayed high in vitro potency across a panel of cell lines, indicating that the incorporation of a linker was not detrimental to their overall potency. Furthermore, we found that the potency of these linkable BIAs could be modulated by careful selection of substituents on the bis-aryl moiety providing enhanced binding affinity with DNA. Upon identification of lead BIA molecules, conjugates with a folate receptor-α (FRα)-binding antibody were prepared. These ADCs displayed potent, antigen-specific in vitro activity across a panel of FRα-expressing cell lines. In vivo, these ADCs demonstrated potent efficacy in xenograft models at doses well below the maximum tolerated dose. In light of these findings, BIA ADCs represent a promising new class of DNA alkylating effector molecules for use in the development of ADCs.

Citation Format: Michael L. Miller, Emily E. Reid, Katie E. Archer, Manami Shizuka, Molly A. McShea, Erin K. Maloney, Olga Ab, Leanne Lanieri, Alan J. Wilhelm, Jose F. Ponte, Nicholas C. Yoder, Ravi V. Chari. A new class of DNA alkylating indolino-benzodiazepine agents (BIAs) linked with a DNA binding moiety for use with antibody-drug conjugates (ADCs) [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 747.
Abstract 756: Development of next-generation antibody-drug conjugates for resistant HER2-positive tumors
Authors: Lacasse Vincent , Leyton Jeffrey V. , Beaudoin Simon , Barok Mark , Joensuu Heikki
Published: August 2018

Antibody-Drug Conjugates (ADC) represent a promising therapeutic modality for improving the clinical management of cancer. However, there now exists resistant mechanisms by cancer cells that are effective at ultimately reducing the cellular accumulation of the delivered drug and hence, reducing cytotoxic effectiveness. Kadcyla® (trastuzumab-emtansine [T-DM1]) is a benchmark as it is the first solid-tumor approved ADC. Despite this new therapeutic option, approximately 43% of patients achieve complete or partial response and most who initially respond develop resistance soon after. In order to transform current ADCs to more effective products improved intracellular delivery strategies could provide solutions. Our group developed is a natural composite compound (termed Accum) that conjugates to surface lysines and enables antibodies to escape endosomal entrapment followed by active routing to the nucleus. Modified antibodies retain high tumor cell selectivity, enhanced cellular accumulation, and improved tumor delivery of molecular payloads in vivo. We asked whether the modification of Accum-modified T-DM1 maintained its intracellular delivery mechanism and cytotoxic effectiveness in T-DM1-resistant cells. The cancer cell lines N87, OE19 (gastric), JIMT1, SK-BR-3 (breast), SKOV3 and SKOV3.IP1 (ovarian) were treated with increasing concentrations of T-DM1 in a 3 day on, 10 days off fashion for a period of 1 to 2 months. Resistant clones were identified. Parental and resistant cells were placed and passaged in SILAC (Stably Labeled Amino acid for Cell culture) media for proteomic analysis by liquid chromatography tandem mass spectrometry (LC-MS/MS). Cells were also treated with Accum-T-DM1 and mechanistic underpinnings determined. The IC50 of Accum-T-DM1 was increased 50- and 10-fold relative to T-DM1 in parental OE19, and JIMT1 cells, respectively. T-DM1 resistant cell lines were successfully generated for each tumor type. Typically, the T-DM1 IC50 values were increased ≥100-fold in resistant cells compared to parental cells. Preliminary proteomic studies revealed HER2 expression is marginally reduced in resistant cells. IP of Accum-T-DM1 co-precipitated showed the interaction with α-importin. This study is a work in progress of modifying T-DM1 with Accum and demonstrating enhanced cytotoxicity in T-DM1 resistant HER2-positive tumor cells. Ongoing studies will determine DM1 accumulation levels, potential resistance mechanisms, and ultimately cytotoxic effectiveness.

Citation Format: Vincent Lacasse, Jeffrey V. Leyton, Simon Beaudoin, Mark Barok, Heikki Joensuu. Development of next-generation antibody-drug conjugates for resistant HER2-positive tumors [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 756.
Abstract 759: Preclinical evaluation of a GFRA1 targeted antibody-drug conjugate in breast cancer
Authors: Bosco Emily E. , Christie Ronald J. , Carrasco Rosa , Sabol Darrin , Zha Jiping , DaCosta Karma , Brown Lee , Phipps Sandrina , Du Qun , Bezabeh Binyam , Breen Shannon , Chen Cui , Reed Molly , Hinrichs MaryJane , Zhong Haihong , Xiao Zhan , Dixit Rakesh , Herbst Ronald , Tice David A.
Published: August 2018

Despite recent advances in treatment, breast cancer remains the second-most common cause of cancer death among American women. A greater understanding of the molecular characteristics of individual tumors could ultimately lead to improved treatment options, particularly for subsets of breast cancer patients with unmet needs. Using an unbiased genomics approach to identify membrane-localized tumor associated antigens (TAAs), we have identified a novel breast cancer TAA that can potentially be exploited through antibody-drug conjugate (ADC) therapy. Here, we describe the development of a GFRA1-targeted ADC that demonstrates activity in GFRA1-positive cell lines and PDX tumor models. Work in non-Good Laboratory Practice (GLP) rat toxicology models revealed acceptable toxicity profiles and supports further evaluation of GFRA1-PBD in GFRA1-positive tumors.

Citation Format: Emily E. Bosco, Ronald J. Christie, Rosa Carrasco, Darrin Sabol, Jiping Zha, Karma DaCosta, Lee Brown, Sandrina Phipps, Qun Du, Binyam Bezabeh, Shannon Breen, Cui Chen, Molly Reed, MaryJane Hinrichs, Haihong Zhong, Zhan Xiao, Rakesh Dixit, Ronald Herbst, David A. Tice. Preclinical evaluation of a GFRA1 targeted antibody-drug conjugate in 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 759.
Abstract 769: Zeb-1 contributes to the development of chemotherapeutic resistance in mantle cell lymphoma
Authors: Luanpitpong Sudjit , Poohadsuan Jirarat , Janan Montira , Thumanu Kanjana , Rojanasakul Yon , Issaragrisil Surapol
Published: August 2018

Despite progress overall in improving cancer treatments, the complete response of mantle cell lymphoma (MCL) is still limited due to the inevitable development of drug resistance. Understanding how MCL cells acquire resistance at the molecular level may be a key innovation to targeted therapy. We established a series of bortezomib (BTZ)-resistant MCL cells and performed gene/protein profiling along with metabolic fingerprinting using synchrotron-based Fourier-transform infrared spectroscopy. Zeb-1, an epithelial-mesenchymal transition-inducing transcription factor better known for promoting metastasis in solid carcinomas, was found to be aberrantly expressed in the resistant MCL cells in accordance with an excessive production of lipids. Ectopic expression of Zeb-1 in parental MCL cells rendered the cells to acquire apoptosis resistance to BTZ. Here we demonstrated, for the first time, two possible encompassing mechanisms for Zeb-1-mediated BTZ resistance: (i) Zeb-1 induces cancer stem cells, as evaluated by tumor spheres and aldehyde dehydrogenase activity; and (ii) Zeb-1 induces lipid reprograming that may interfere with cell growth and drug response. Together, our results unveil a novel role of Zeb-1 in MCL aggressiveness. These findings have a clinical significance insight to the development of chemotherapeutic resistance of MCL.

Citation Format: Sudjit Luanpitpong, Jirarat Poohadsuan, Montira Janan, Kanjana Thumanu, Yon Rojanasakul, Surapol Issaragrisil. Zeb-1 contributes to the development of chemotherapeutic resistance in mantle cell lymphoma [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 769.
Abstract 775: HIPStA, a high-throughput alternative to CETSA®
Authors: Cho Kelvin F. , Rose Christopher , Ma Taylur , Kirkpatrick Donald , Blake Robert A.
Published: August 2018

The measurement of drug - target interaction in the cellular context is critical to many drug development programs. The Cellular Thermal Stability Assay (CETSA®) represents an established broadly applicable method for measuring drug target interaction. However, in its classic format, it has some limitations that make it difficult to scale to the throughput typically required for a drug development project. It requires heating samples to different temperatures and centrifugation and / or filtration steps which limit throughput. The HSP90 Inhibitor Protein Stability Assay (HIPStA) is a novel method for measuring drug target interaction. Like CETSA®, HIPStA is based on the premise that the binding of a ligand to a target protein can influence that protein's stability. Instead of using heat to destabilize a protein, HIPStA uses a Heat Shock Protein 90 inhibitor (HSP90i) to cause protein instability. Instead of scanning a range of different temperatures to establish a thermal denaturation curve, HIPStA applies a range of concentrations of an HSP90i to determine an HSP90i induced denaturation curve, and ultimately measures the ability of a compound to stabilize a protein. We present data demonstrating the proof of concept for the HIPStA method, using 3 different classes of drug discovery targets: Receptor tyrosine kinases, Nuclear Hormone Receptors and Cytoplasmic Protein Kinases. HIPStA represents a scale-able method for detecting drug-target interaction in cells.

Citation Format: Kelvin F. Cho, Christopher Rose, Taylur Ma, Donald Kirkpatrick, Robert A. Blake. HIPStA, a high-throughput alternative to CETSA® [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 775.
Abstract 780: Molecular chaperone is a novel biomarker for disease outcome in multiple myeloma
Authors: Li Yingqi , Zhang Ping L. , Li Zihai , Liu Bei
Published: August 2018

Multiple myeloma (MM) is an incurable plasma cell neoplasm whose pathogenesis is closely linked to dysregulated unfolded protein response (UPR) in the endoplasmic reticulum (ER). MM typically evolves from an asymptomatic premalignant stage called monoclonal gammopathy of undetermined significance (MGUS), to an intermediate asymptomatic smoldering MM (SMM), to eventually symptomatic MM. However, no single pathologic or molecular biomarker can be used to distinguish MM patients from SMM, who have clonal premalignant plasma cells from those with clonal myeloma cells. Therefore, there is a compelling need for further development of novel diagnosis and prognosis biomarkers for MM. Heat shock protein grp94 is a key downstream chaperone in the ER to mediate UPR. Using genetic approaches, we have demonstrated that grp94 is an obligate chaperone for Wnt co-receptor low-density lipoprotein receptor-related protein 6 and that it is required for multiple myeloma cell survival, which is mediated in part by the Wnt target survivin. Moreover, we found that grp94 is highly expressed in malignant plasma cells in MM, and the higher level of grp94 is significantly associated with more advanced stage of this disease. Additionally, the grp94 expression is significantly associated with the levels of serum M protein in MM patients, but not in patients with MGUS and SMM. Thus, our studies demonstrated that molecular chaperone grp94 is a novel diagnostic and prognostic biomarker for MM as well as a potential target for treatment of this disease.

Citation Format: Yingqi Li, Ping L. Zhang, Zihai Li, Bei Liu. Molecular chaperone is a novel biomarker for disease outcome in multiple myeloma [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 780.
Abstract 800: ABBV-744, a first-in-class and highly selective inhibitor of the second bromodomain of BET family proteins, displays robust activities in preclinical models of acute myelogenous leukemia
Authors: Lin Xiaoyu , Huang Xiaoli , Bellin Richard , Faivre Emily , Hessler Paul , Lam Lloyd , Bui Mai Ha , Wilcox Denise , Uziel Tamar , Ferguson Debra C. , Magoc Terrance J. , Albert Daniel H. , McDaniel Keith F. , Kati Warren , Shen Yu
Published: August 2018

Many small-molecule inhibitors that target both bromodomains of the BET family proteins (pan BET inhibitors) are undergoing studies in clinical trials. Emerging data are beginning to suggest that clinical responses to these pan BET inhibitors in subsets of hematologic malignancies may be modest and short lived, perhaps due, at least in part, to tolerability issues that limit dosing levels. We hypothesized that selective inhibition of four of the eight bromodomains in BET family proteins might retain the anticancer activities in certain tumor subsets while alleviating some of the tolerability liabilities of pan BET inhibitors, thus possibly providing better therapeutic benefits. ABBV-744 is a highly selective inhibitor for the second bromodomain (BDII) of the four BET family proteins, exhibiting greater than 300-fold more potent binding affinity to the BDII bromodomain of BRD4 relative to the first bromodomain (BDI) of BRD4. In contrast to the broad antiproliferative activities observed with pan BET inhibitors, ABBV-744 only displayed significant antiproliferative activities in a limited number of cancer cell lines, including AML and androgen receptor (AR)-positive prostate cancer. Studies in AML xenograft models demonstrated antitumor efficacy for ABBV-744 that was comparable to the pan-BET inhibitor ABBV-075 but with improved tolerability. Taken together, these results suggest that ABBV-744 could be a promising second-generation BET inhibitor for AML therapy.

Affiliation: Oncology Discovery, AbbVie Inc., 1 North Waukegan Rd., North Chicago, IL 60064. Disclosures: All authors are employees of AbbVie. The design, study conduct, and financial support for this research were provided by AbbVie. AbbVie participated in the interpretation of data, review, and approval of the publication.

Citation Format: Xiaoyu Lin, Xiaoli Huang, Richard Bellin, Emily Faivre, Paul Hessler, Lloyd Lam, Mai Ha Bui, Denise Wilcox, Tamar Uziel, Debra C. Ferguson, Terrance J. Magoc, Daniel H. Albert, Keith F. McDaniel, Warren Kati, Yu Shen. ABBV-744, a first-in-class and highly selective inhibitor of the second bromodomain of BET family proteins, displays robust activities in preclinical models of acute myelogenous 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 800.
Abstract 827: Anti-tumor efficacy of BA3011, a novel Conditionally Active Biologic (CAB) anti-AXL-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

AXL is a TAM family receptor tyrosine kinase that has been implicated in the pathogenesis of many cancer types. The high level of expression on the cancer cell surface and increased expression in various settings such as PD-1 resistant tumors makes AXL a particularly attractive target for antibody therapeutics. However, AXL is expressed on many normal tissues and has been implicated in wide ranging requisite biological processes including response of endothelial cells to vascular injury, hematopoiesis, and regulation of immune responses. This normal tissue expression combined with the presence of soluble AXL may limit AXL as a target for antibody-drug-conjugates (ADC). The Conditionally Active Biologics (CAB) technology is a patented, proprietary platform that generates 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-AXL CAB Abs that reversibly bind to recombinant AXL and AXL expressing cells under conditions that are present in the tumor microenvironment, but not in normal tissues.

BA3011 is a CAB-AXL-ADC. The pharmacological properties of BA3011 were characterized in a number of in vitro and in vivo pharmacology studies. BA3011 binds selectively to human and cyno AXL in conditions reflective of the tumor microenvironment, but has reduced binding under normal tissue conditions. BA3011 demonstrated the ability to induce cytotoxicity of human tumor cell lines expressing AXL in vitro and inhibit tumor growth in LCLC-103H (lung), DU145 (prostate), and MIAPaCa-2 (pancreatic) human tumor xenografts and in selected gemcitabine resistant pancreatic cancer patient derived xenograft models in vivo.

In conclusion, our data is consistent with our work on CAB-EGFR-ADC, CAB-ROR2-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-AXL-ADC is an excellent candidate for evaluation as a treatment for human cancers that are AXL 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 BA3011, a novel Conditionally Active Biologic (CAB) anti-AXL-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 827.
Abstract 828: Targeting the MET oncogene by concomitant inhibition of receptor and ligand by an antibody-‘decoy' strategy
Authors: Basilico Cristina , Modica Chiara , Maione Federica , Vigna Elisa , Comoglio Paolo M.
Published: August 2018

Background: MET, a master gene sustaining ‘invasive growth', is a relevant target for cancer precision therapy. In a limited number of cases, a MET genetic lesion drives the malignant phenotype in ligand-independent manner (oncogene ‘addiction'). In the vast majority of tumors, however, wild-type MET behaves as a ‘stress-response' gene and relies on the ligand (HGF) to sustain cell ‘scattering', invasive growth and apoptosis protection (oncogene ‘expedience'). In this context -i.e. ligand-dependent MET activation- concomitant targeting of MET and HGF could be crucial to reach effective inhibition. Methods: To test this hypothesis we combined an anti-MET antibody (MvDN30), characterized by the property of inducing ‘shedding' (i.e. removal of MET from the cell surface), with a ‘decoy' (i.e. the soluble extracellular domain of the MET receptor) endowed with HGF-sequestering ability. To avoid antibody/decoy interaction -and subsequent neutralization- we identified by site directed mutagenesis a single aminoacid in the extracellular domain of MET -lysine 842- that is critical for MvDN30 binding, and engineered the corresponding recombinant decoyMET (K842E). The effect of MvDN30 and decoyMETK842E in combination on the inhibition of MET phosphorylation and on the impairment of different MET driven biological responses (motility, invasion, cell proliferation, apoptosis and anchorage independent cell growth) was evaluated on a panel of cancer cells (lines and patient derived-primary cultures) expressing wild-type MET sensitive to HGF stimulation. Therapeutic efficacy was assessed in an orthotopic model of pancreatic cancer generated in SCID mice engineered to express human HGF. Results: The decoyMETK842E retains the ability to bind HGF with high affinity and inhibits HGF-induced MET phosphorylation. In HGF-dependent cellular models, MvDN30 antibody and decoyMETK842E used in combination cooperate in restraining invasive growth, and synergize in blocking cancer cell ‘scattering'. The antibody and the decoy unbridle apoptosis of colon cancer stem cells grown in vitro as spheroids. In the preclinical model of MET ‘expedience' concomitant treatment with antibody and decoy significantly reduces metastatic spread. Conclusions: The data reported indicate that vertical targeting of the MET/HGF axis results in powerful inhibition of ligand-dependent MET activation, providing proof of concept in favor of combined targeted therapy of MET ‘expedience'.

Citation Format: Cristina Basilico, Chiara Modica, Federica Maione, Elisa Vigna, Paolo M. Comoglio. Targeting the MET oncogene by concomitant inhibition of receptor and ligand by an antibody-‘decoy' strategy [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 828.
Abstract 830: ISU104, a fully human antibody targeting a specific epitope on the ErbB3, displays potent inhibition of tumor growth in multiple xenograft tumor models
Authors: Kim Miyoung , Hur Youngmi , Seo Sohyeon , Lim Heynjeong , Kim Kyungyong , Sohn Youngsoo , Hong Seung-Beom , Bae Donggoo
Published: August 2018

Members of the epidermal growth factor receptor family (ErbB family) are known as potent mediators in the development and progression of cancer. Activated ErbBs recruit various adaptors and signaling molecules through the phosphorylated cytoplasmic domain, which further leads to activation of downstream oncogenic signaling pathways. There are approved therapeutics for ErbB1 (EGFR) and ErbB2 (HER2) in the treatment of human cancers, while monoclonal antibodies targeting ErbB3 are just undergoing clinical trials. ISU104 is a fully human anti-ErbB3 antibody isolated from phage display antibody library. We performed the hydrogen/deuterium exchange mass spectrometry (HDX-MS) analysis with ErbB3 extracellular domain and ISU104, and that indicated that ISU104 mainly binds with domain 3 and weakly interacts with domain 1 of ErbB3. The binding property of ISU104 induced dose-dependent inhibition of ligand (heregulin, HRG) binding, blocking of dimerization of ErbB3 with other ErbBs and subsequently inactivated the downstream signaling of ErbB3. Also, ISU104 occasioned internalization of ErbB3 from plasma membrane, and downregulated the expression level of ErbB3. We demonstrated the biologic effect of ISU104 in several ErbB3-expressing cancer cell lines, including head and neck squamous cell carcinoma (HNSCC) and breast cancers. ISU104 completely suppressed the HRG-induced ErbB3/AKT phosphorylation, reduced cell proliferation and survival. Next, we evaluated efficacy of ISU104 in multiple xenograft models. Mice were treated with 10 mg/kg of ISU104 twice weekly. ISU104 regressed tumor growth in FaDu HNSCC model, and showed more than 70% tumor growth inhibition (TGI) in CAL27 (HNSCC), BxPC3 (pancreatic cancer), MDA-MB-468 (breast cancer), A549 (skin cancer), and BT474 (breast cancer) models. Our results suggest that ISU104 effectively blocks activation of ErbB3 and the downstream pathway by ErbB3, and may provide clinical benefit to ErbB3-activated patients.

Citation Format: Miyoung Kim, Youngmi Hur, Sohyeon Seo, Heynjeong Lim, Kyungyong Kim, Youngsoo Sohn, Seung-Beom Hong, Donggoo Bae. ISU104, a fully human antibody targeting a specific epitope on the ErbB3, displays potent inhibition of tumor growth in multiple xenograft tumor 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 830.
Abstract 846: Co-targeting of Axl and MerTK improves radiation response in HNSCC
Authors: Abbariki Mahyar , Toulany Mahmoud , Iida Mari , Morgan Alecia , Nickel Kwang , McDaniel Nellie , Kang Grace , Li Chunrong , Harari Paul , Wheeler Deric
Published: August 2018

Axl and MerTK are members of the TAM family (Tyro, Axl and MerTK) of receptor tyrosine kinases and have been reported to be altered in several types of cancer including Head and Neck Squamous Carcinoma (HNSCC). It is well known that aberrant expression or activity of Axl is associated with resistance to various therapies. Therefore, the translational potential of targeting AXL in HNSCC is worthy, however poorly defined. We recently identified an adaptive feedback mechanism of resistance to AXL-targeting agents mediated by upregulation of MerTK that reveals a direct role for MerTK in resistance to Axl inhibition. In this study, we investigated potential radiosensitization by dual targeting of Axl and MerTK in combination with radiation in human HNSCC cell lines and xenografts (SCC47 and TU138). Immunoblot analysis demonstrated that endogenous levels of Axl or MerTK expression were distinct between these two cell lines. SCC47 cells expressed higher endogenous levels of Axl compared to Tu138. Tu138 expressed higher levels of MerTK compared to SCC47 cells. Radiation induced Axl phosphorylation in SCC47 cells but not in Tu138 cells in vitro. Next, inhibitors of Axl (R428) and/or MerTK (UNC2025) were utilized in combination with single dose radiation in vitro. Clonogenic assays showed that the Axl inhibitor alone acted as a potent radiosensitizer in SCC47 cells. To better define Axl's role in radiation response in HNSCC, we developed HN30-Vector and HN30-Axl stable cells and exposed them to radiation. Phosphorylation of Axl was increased 1 hour post-radiation in Axl overexpressed HN30 compared to parental HN30-Vector which expresses low endogenous levels of Axl. We also found that the HN30-Axl cell line was associated with radioresistance by clonogenic assays. Tumor xenograft studies demonstrated that the combination of R428 and UNC2025 inhibitors improved the efficacy of radiation in Tu138 but not in SCC47. Interestingly, radiation therapy alone was more effective in SCC47 tumors than TU138 tumors. These results reveal that the co-targeting of Axl and MerTK enhanced tumor growth delay in TU138 xenograft mouse models in vivo. Mechanisms of radiosensitization are currently under investigation.

Citation Format: Mahyar Abbariki, Mahmoud Toulany, Mari Iida, Alecia Morgan, Kwang Nickel, Nellie McDaniel, Grace Kang, Chunrong Li, Paul Harari, Deric Wheeler. Co-targeting of Axl and MerTK improves radiation response in HNSCC [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 846.