bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract A119: Inhibition of IRE1-mediated pro-tumorigenic responses enhances the sensitivity of MDA-MB-231 cells to the novel arylurea-fatty acid CTU
Authors: Rahman Md Khalilur , Rawling Tristan , Al-Zubaidi Yassir , Choucair Hassan , Umashankar Bala , Chen Yongjuan , Bourget Kirsi , Tam Stanton , Smith Charlotte , Murray Michael
Published: March 2020

There is an unmet need for new agents with low toxicity for treatment of triple-negative breast cancer (TNBC) because current approaches are limited to toxic drug combinations of low efficacy. We recently identified an aryl-substituted fatty acid analogue, termed CTU, that effectively killed TNBC cells in vitro and in mouse xenograft models in vivo without producing toxicity (Rawling et al., 2017). However, there was a residual cell population that survived CTU. The present study evaluated the mechanism underlying residual cell survival. From RNA-seq profiling, a major regulated process in CTU-treated cells was activation of the unfolded response and endoplasmic reticulum (ER)-stress. The ER transmembrane protein inositol-requiring enzyme 1 (IRE1) is a central mediator of the unfolded response and ER-stress that was activated by CTU. IRE1 is also implicated as a pro-tumorigenic factor that can activate the expansion of tumor-initiating cells. From RNA-seq several pro-tumorigenic factors, including cyclooxygenase-2 and the cytokines IL6, IL8 and GM-CSF, were strongly activated in CTU-treated cells; this was confirmed by real-time RT-PCR and Western blot analysis. Using the non-adherent, in vitro colony-forming mammosphere assay, that enables the quantification of cell self-renewal, it was found that CTU expanded tumor-initiating cells. Co-treatment with an inhibitor of IRE1 impaired IRE1 kinase and IRE1 RNase activities, as reflected by decreases in phospho-p65 and XBP1s expression. IRE1 inhibition also prevented the activation of pro-tumorigenic factors and self-renewal by CTU. Taken together, the present findings suggest that inhibition of IRE1 may be a novel approach to optimise the activity of CTU in TNBC.

Citation Format: Md Khalilur Rahman, Tristan Rawling, Yassir Al-Zubaidi, Hassan Choucair, Bala Umashankar, Yongjuan Chen, Kirsi Bourget, Stanton Tam, Charlotte Smith, Michael Murray. Inhibition of IRE1-mediated pro-tumorigenic responses enhances the sensitivity of MDA-MB-231 cells to the novel arylurea-fatty acid CTU [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics; 2019 Oct 26-30; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2019;18(12 Suppl):Abstract nr A119. doi:10.1158/1535-7163.TARG-19-A119
Abstract A135: Discovery of BGS1954, a covalent small molecule ligand of FABP5 using IMTACTM platform
Authors: Chen Hang , Ha Heather , Stanley Robert , Huang Cindy , Cai Qian , Yuan Irene , Cao Ping
Published: March 2020

Fatty acid-binding protein-5 (FABP5) or epidermal FABP belongs to a low molecular weight lipid binding protein family. FABP5 is involved in binding, storing, and transporting hydrophobic ligands to the proper cellar compartment. Recent studies have suggested that FABP5 play important roles in regulation of gene expression associated with with cell growth and differentiation. FABP5 expression level was closely related to malignency in several types of cancers. The functions of FABP5 in modulation of cellular signaling have been studies and suggested that FABP5 is involved in EGFR, NFkB and PPAR pathways. Using IMTACTM (Isobaric Mass Tagged Affinity Characterization) to screen small molecule library in live cancer cells, ligands covalently bound to FABP5 were identified. Our initial characterization of compounds showed that they specifically bind to FABP5 and inhibit cancer cell growth. These FABP5-specific covalent small molecule ligands will provide a valuable pharmacological tool to dissect FABP5 functions and shed light on the therapeutic potential of targeting FABP5 for the treatment of cancer and metabolic disorders.

Citation Format: Hang Chen, Heather Ha, Robert Stanley, Cindy Huang, Qian Cai, Irene Yuan, Ping Cao. Discovery of BGS1954, a covalent small molecule ligand of FABP5 using IMTACTM platform [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics; 2019 Oct 26-30; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2019;18(12 Suppl):Abstract nr A135. doi:10.1158/1535-7163.TARG-19-A135
Abstract B002: Discovery of selective and potent EGFR kinase inhibitors for exon20 insertion mutations
Authors: Kim Sunghwan , Lee Younho , Kim Hwan , Kang Juhee , Seok Jiyoon , Seo Kyung-Ah , Ahn Jaeyoung , Kang Hee-Bum , Lee Sun-Hwa , Son Jung Beom , Choi Hwan Geun , Kim Nam Doo
Published: March 2020

The third generation EGFR tyrosine kinase inhibitors (TKIs), like Osimertinib, target classical activating EGFR mutations containing T790M resistance mutation. However, the exon 20 insertion (Ex20Ins), the third most common EGFR mutations in entire NSCLC, still lacks its therapeutic option. Recently, Robichaux JP et al., showed that Poziotinib, which had been developed as a second-generation EGFR TKI, had efficacy for the EGFR and Her2 Ex20Ins compared to EGFR T790M. Here, we developed inhibitors, structurally distinct from both Poziotinib and Osimertinib, targeting for the EGFR Ex20Ins mutations as well as EGFR T790M. According to kinase profiling, the inhibitors are highly selective to EGFR, ERBB2 and ERBB4 family. The candidate inhibitors demonstrated great activity (GI50 < 20 nM) in cell growth inhibition of Ba/F3 cells containing EGFR Ex20Ins (D770_N771insSVD, V769_D770insASV, D770_N771insNPG, A763_Y764insFQEA, and H773_V774insNPH), Her2 Ex20Ins (A775_G776insYVMA), or cancer cells containing activating EGFR mutations and T790M resistance mutation (L858R/T790M and Del19/T790M). Finally, in several Ex20Ins patient-derived xenograft models, the candidate inhibitors induced tumor regression as strong as Poziotinib and increased survival rates along with minimal weight loss. These novel small molecule compounds inhibiting EGFR exon 20 insertion mutations will provide future therapeutic options for patients with this molecular subtype of NSCLC.

Citation Format: Sunghwan Kim, Younho Lee, Hwan Kim, Juhee Kang, Jiyoon Seok, Kyung-Ah Seo, Jaeyoung Ahn, Hee-Bum Kang, Sun-Hwa Lee, Jung Beom Son, Hwan Geun Choi, Nam Doo Kim. Discovery of selective and potent EGFR kinase inhibitors for exon20 insertion mutations [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics; 2019 Oct 26-30; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2019;18(12 Suppl):Abstract nr B002. doi:10.1158/1535-7163.TARG-19-B002
Abstract B006: Targeting EZH2 increases therapeutic efficacy of PD-1 blockade in models of prostate cancer
Authors: Sheahan Anjali , Morel Katherine , Burkhart Deborah , Baca Sylvan , Labbè David , Roehle Keven , Calagua Carla , Ye Huihui , Galbo Phillip , Panja Sukanya , Mitrofanova Antonina , Hamid Anis , Kibel Adam , Choudhury Atish , Pomerantz Mark , Freedman Matthew , Sweeney Christopher , Dougan Stephanie , Sowalsky Adam , Olson Brian , Loda Massimo , Ellis Leigh
Published: March 2020

Prostate cancers are considered immunologically ‘cold’ tumors as they have demonstrated poor response to check-point inhibitor therapy (CPI). Recently, enrichment of interferon response genes suggests a favorable response to CPI across various disease sites. The enhancer of zeste homolog-2 (EZH2) is over-expressed in prostate cancer and is known to negatively regulate IFN response genes. Here, we demonstrate that inhibition of EZH2 catalytic activity in prostate cancer models increases expression of double-strand RNA (dsRNA), that is associated with upregulation of genes connected with antigen presentation, Th-1 chemokine signaling, and interferon (IFN) response genes, including PD-L1. Likewise, application of a novel EZH2 derived gene signature and TMA analysis indicated an inverse correlation between tumor EZH2 activity/expression with, T-cell inflamed and IFN gene signatures, and PD-L1 expression in human prostate cancer samples. EZH2 inhibition combined with PD-1 CPI significantly enhances anti-tumor response that is dependent on up-regulation of tumor PD-L1 expression. Further, combination therapy significantly increases intratumoral trafficking of activated CD8+ T-cells and M1 tumor associated macrophages (TAMs) with concurrent loss of M2 TAMs. Our study identifies EZH2 as a potent inhibitor of antitumor immunity and responsiveness to CPI. This data suggests EZH2 inhibition as a novel therapeutic direction to enhance prostate cancer response to PD-1 CPI.

Citation Format: Anjali Sheahan, Katherine Morel, Deborah Burkhart, Sylvan Baca, David Labbè, Keven Roehle, Carla Calagua, Huihui Ye, Phillip Galbo, Sukanya Panja, Antonina Mitrofanova, Anis Hamid, Adam Kibel, Atish Choudhury, Mark Pomerantz, Matthew Freedman, Christopher Sweeney, Stephanie Dougan, Adam Sowalsky, Brian Olson, Massimo Loda, Leigh Ellis. Targeting EZH2 increases therapeutic efficacy of PD-1 blockade in models of prostate cancer [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics; 2019 Oct 26-30; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2019;18(12 Suppl):Abstract nr B006. doi:10.1158/1535-7163.TARG-19-B006
Abstract B015: Targeting histone demethylase KDM4 for cancers driven by chimeric transcription factors
Authors: Yang Jun , Singh Shivendra , Abu-Zaid Ahmed , Fang Jie , Davidoff Andrew
Published: March 2020

Chimeric transcription factors drive lineage-specific oncogenesis but are notoriously difficult to target for cancer therapy as they usually do not bear druggable pockets. Alveolar rhabdomyosarcoma (aRMS) is an aggressive childhood soft tissue sarcoma, mainly driven by the pathognomonic PAX3-FOXO1 or its variant PAX7-FOXO1 fusion oncoprotein. Even with intensive chemotherapy and radiotherapy, the 5-year survival for fusion positive aRMS is poor with no significant improvement in over recent decades. Here we show that PAX3-FOXO1 function is dependent on histone demethylase KDM4B, a potential therapeutic vulnerability for aRMS. KDM4B is highly expressed in PAX3-FOXO1-positive aRMS and is associated with late stage disease. KDM4B physically interacts with PAX3-FOXO1 via its JmjN and TUDOR domains. Genetic depletion and pharmacologic inhibition of KDM4B with a novel inhibitor QC6352 significantly delay tumor growth, impact the expression of FAX3-FOXO1 targets such as MYOD1 and FGFR4, and reduce chromatin accessibility of PAX3-FOXO1 target genes in accordance with the changes of KDM4B substrates such as H3K9me3. Combination of QC6352 with chemotherapy lead to significant xenograft regression and extended mouse survival in cell line- and PDX- based preclinical aRMS models. In summary, we have identified a targetable epigenetic modifier required for the functions of PAX3-FOXO-driven aRMS, providing pre-clinical data for a clinal trial combining the KDM4 inhibitor with standard chemotherapy for high-risk aRMS.

Citation Format: Jun Yang, Shivendra Singh, Ahmed Abu-Zaid, Jie Fang, Andrew Davidoff. Targeting histone demethylase KDM4 for cancers driven by chimeric transcription factors [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics; 2019 Oct 26-30; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2019;18(12 Suppl):Abstract nr B015. doi:10.1158/1535-7163.TARG-19-B015
Abstract B079: Inhibitory role of NFE2L2/NRF2-silencing in hypoxia-induced metabolic adaptation of cancer cells
Authors: Kwak Mi-Kyoung , Lee Sujin , Hallis Steffanus Pranoto
Published: March 2020

The nuclear factor erythroid 2-like-2 (NFE2L2/NRF2) pathway contributes to the environmental resistance of cancers by enhancing the antioxidant capacity. Hypoxia, a common element in the tumor environment, leads to hypoxia-inducible factor-1α (HIF-1α) stabilization to induce the adaptive response to hypoxic condition, including metabolic reprogramming and blood vessel formation. Our global miRNA expression analysis of HT29 and HCT116 human colon cancer cells identified that NRF2 silencing upregulated miR-181c, and this increase was associated with the reduction in mitochondria-encoded cytochrome c oxidase subunit-1 (MT-CO1), a catalytic core subunit of the complex IV of the electron transport chain. Therefore, NRF2-silenced cancer cells exhibited the decreases in the mitochondrial membrane potential, oxygen consumption rate, and cellular ATP contents. Notably, as a result of low oxygen consumption rate, NRF2-inhibited cancer cells failed to accumulate HIF-1a protein under hypoxic conditions. This phenomenon led to differential responses of NRF2-inhibted cancer cells to hypoxic condition when compared to control cells. First, stable knockdown of NRF2 in human colon cancer cells suppressed tumor growth in mouse xenograft settings with a concomitant reduction in blood vessel formation and vascular endothelial growth factor expression. Second, NRF2-silencing in breast cancer cells inhibited metabolic adaptation upon hypoxia, and hypoxic-inducible levels of metabolites involved in glycolysis and pentose phosphate pathway were reduced. Collectively, targeting NRF2/miR-181c could be an effective strategy to counteract HIF-1α-orchestrated adaptation of cancer cells to hypoxic microenvironment.

Citation Format: Mi-Kyoung Kwak, Sujin Lee, Steffanus Pranoto Hallis. Inhibitory role of NFE2L2/NRF2-silencing in hypoxia-induced metabolic adaptation of cancer cells [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics; 2019 Oct 26-30; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2019;18(12 Suppl):Abstract nr B079. doi:10.1158/1535-7163.TARG-19-B079
Abstract B094: Novel method for patient stratification in breast carcinoma based upon spatial analysis of tumor microenvironment
Authors: Ziegler Colleen , Slemons Isaiah , DeSilva Chris , Witkowski Barbara , Mir Alain , Anandakrishnan Sangeetha , Farmer Andrew , Contreras Elma , Richardson David , Vranic Semir , Gatalica Zoran , Derkach Dmitry N.
Published: March 2020

Breast cancer consists of several intrinsic molecular subtypes, providing the basis for clinical treatment decisions. Lately, it is becoming increasingly recognized that factors other than the intrinsic cancer characteristics, such as immune components’ activity in the tumor microenvironment, have important effects on treatment choices and efficacy. bioSyntagma has developed a method, the Molecular Fingerprint (mPrint®), that enables multiplexed analysis of spatially defined regions in formalin-fixed, paraffin-embedded (FFPE) tumor samples allowing for analysis of the gene signatures unique to the tumor microenvironment. This method was applied to molecularly defined sets of breast cancers and used to evaluate four different tumor regions of interest (ROIs): 1) viable carcinoma proper (>90% cancer cells), 2) fibrotic tumor center (sparse cellularity), 3) interface between viable tumor and inflammatory component (tumor and inflammatory microenvironment) and 4) tissue away from the tumor (normal breast tissue). This was compared to the whole tissue scrapes from each patient block. Each ROI and tissue scrape was analyzed by high throughput qPCR for a panel of 248 genes using SmartChip technology (Takara Bio, USA). Sequential tissue slices from each patient were also analyzed using immunohistochemistry (IHC) for three targets and investigated for correlation with qPCR results for validation of the method. Overall, reasonable concordance was observed in general expression trends between selected IHC and RNA expression. qPCR data were further analyzed using hierarchical clustering analysis and showed that morphologically defined ROI’s cluster completely differently than traditional clustering of entire tissue scrapes. Notably, patient clustering based on morphological regions was independent of the intrinsic cancer subtype, as determined by molecular profiling of whole tissue scrapes, as well as independent of trends in Tumor Mutational Burden (TMB) and Microsatellite Instability (MSI). These findings suggest that current methods of patient stratification based on whole tumor molecular subtyping may be inferior to stratification based on molecular characteristics of the tumor microenvironment.

Citation Format: Colleen Ziegler, Isaiah Slemons, Chris DeSilva, Barbara Witkowski, Alain Mir, Sangeetha Anandakrishnan, Andrew Farmer, Elma Contreras, David Richardson, Semir Vranic, Zoran Gatalica, Dmitry N. Derkach. Novel method for patient stratification in breast carcinoma based upon spatial analysis of tumor microenvironment [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics; 2019 Oct 26-30; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2019;18(12 Suppl):Abstract nr B094. doi:10.1158/1535-7163.TARG-19-B094
Abstract B110: Assessments of ameliorative effect of Forsythia Fructus on chemotherapy-induced neuropathic pain and its genotoxic potential
Authors: Shin Sarah , Kim Jinhee , Yi Jin-Mu , Kim No Soo , Bang Ok-Sun
Published: March 2020

The Forsythia Fructus (FF) have been prescribed in traditional medicine to relive clinical symptoms such as fever, pain, wound healing, vomiting, and nausea. The present study was performed to evaluate the neuroprotective effect of aqueous extract of FF on oxaliplatin-induced peripheral neuropathic pain; the in vivo neuroprotection activity was evaluated by von Frey test in murine models and in vitro protective effect was measured using PC12 cells. FF significantly alleviated oxaliplatin-induced mechanical hypersensitivity in rat model. In addition, FF exerted the neuroprotection effects against oxaliplatin-induced neurotoxicity as well as -inhibited neurite outgrowths in PC12 cells and dorsal root ganglion cells. In order to assess the safety of FF, we next evaluated genotoxic potential using a standard battery of in vitro and in vivo test system: the bacterial reverse mutation (Ames) test, the chromosomal aberration test, and the micronucleus test with bone marrow cells derived from male ICR mice in accordance with OECD guidelines. The results showed that aqueous extract of FF had not any genotoxic potential under the conditions tested. Taken together, these results indicated that FF will be useful for relieving oxaliplatin-induced peripheral neuropathic pain in cancer patients undergoing chemotherapy without genotoxic potential at least in our experimental condition.

Citation Format: Sarah Shin, Jinhee Kim, Jin-Mu Yi, No Soo Kim, Ok-Sun Bang. Assessments of ameliorative effect of Forsythia Fructus on chemotherapy-induced neuropathic pain and its genotoxic potential [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics; 2019 Oct 26-30; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2019;18(12 Suppl):Abstract nr B110. doi:10.1158/1535-7163.TARG-19-B110
Abstract B111: A herbal formula BP10A enhanced anticancer effect of chemotherapeutic agents in the colon cancer PDTX model
Authors: Kim Jinhee , Shin Sarah , Kim No Soo , Bang Ok-Sun
Published: March 2020

BP10A is a novel two-herb medicine formula, consisting of Descurainiae sophia Semen and Peucedani praeruptorum Radix. This study was done to evaluate the antitumor efficacy of BP10A and its effect on the efficacy of the anticancer drugs oxaliplatin and irinotecan (CPT-11) in a colon tumor xenograft model. Chemical constituents from the ethanol extracts of BP10A were characterized with the ultra-performance liquid chromatography (UPLC) and each constituent was quantified with the UPLC-diode array detector method. Our study showed that BP10A exerted the cytotoxic effects in two colorectal cancer cell lines and its combination treatments with oxaliplatin or CPT-11 remarkably increased the in vitro cytotoxicity of each cancer drug assessed by the Ez-cytox assay. The in vivo antitumor activity of BP10A was evaluated in three colon cancer patient-derived tumor xenograft (PDTX) models with different genetic backgrounds. Oral administration with BP10A (250 and 500 mg/kg, daily) delayed tumor growth by 34-70% in the all PDTX models. Similarly, intraperitoneal injection of oxaliplatin (6 mg/kg) or CPT-11 (20 mg/kg) also suppressed tumor growth by 31.8-60.5% or by 24.3-50.4%, respectively. Furthermore, the combination treatment of BP10A with oxaliplatin or CPT-11 remarkably enhanced the antitumor activity of each anti-cancer drug and delayed tumor growth by 47.1-74.6% or by 74.4-82.9%, respectively. In accordance with the antitumor activity, the Ki-67 expression for tumor cell proliferation and the CD31 for angiogenesis were decreased, and TUNEL staining for tumor cell apoptosis was remarkably increased by the co-treatment of BP10A and the anticancer drugs as well as by each treatment of BP10A, oxaliplatin or CPT-11. Conclusively, BP10A has a strong tumor inhibitory effect against colon cancer and a synergistic effect with anticancer drugs, suggesting that BP10A could be considered as a good therapeutic candidate for the treatment of colon cancer. Funding source: This research was supported by a grant from Korea Institute of Oriental Medicine (K1515294).

Citation Format: Jinhee Kim, Sarah Shin, No Soo Kim, Ok-Sun Bang. A herbal formula BP10A enhanced anticancer effect of chemotherapeutic agents in the colon cancer PDTX model [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics; 2019 Oct 26-30; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2019;18(12 Suppl):Abstract nr B111. doi:10.1158/1535-7163.TARG-19-B111
Abstract B112: Obtusaquinone is a cysteine-modifying compound that targets Keap1 for degradation
Authors: Hora Cintia Carla da , Tabet Elie , Badr Christian Elias , Tannous Bakhos
Published: March 2020

In a previous study, we described the antineoplastic properties of the natural compound Obtusaquinone (OBT) against glioblastoma, breast cancer and other cancer types. We have shown that OBT targets cancer cells by increasing the production of reactive oxygen species (ROS) leading to DNA damage and apoptotic cell death. However, the mechanism behind the tumor targeting properties of OBT is not fully elucidated, hampering further preclinical development. In our current study we combined medical chemistry, quantitative mass-spectrometry-based proteomics, functional cancer cell studies, pharmokinetics and in vivo xenograft models to understand the mechanism of action of this compound and develop new OBT analogues with enhanced pharmacokinetic properties. Mechanistically, we now show that OBT binds cysteine residues, and in particular cysteine residues on Keap1. Our data also demonstrates that binding of OBT to Keap1 leads to its ubiquitination and degradation by the ubiquitin proteasome pathway (UPP). Since Keap1 acts as a negative regulator of Nrf2, its degradation following treatment with OBT results in the activation of Nrf2 signaling. Further, our pharmacokinetic studies demonstrate that OBT is able to cross the blood-brain barrier. In a GBM cancer stem cell xenograft model, OBT treatment results in 50% decrease in glucose uptake as detected using FDG-PET imaging. In conclusion, we show here that OBT binding to Keap1 is crucial for its anti-cancer properties, and that this binding leads to ubiquitination and proteasomal degradation of Keap1 and the activation of Nrf2 pathway.

Citation Format: Cintia Carla da Hora, Elie Tabet, Christian Elias Badr, Bakhos Tannous. Obtusaquinone is a cysteine-modifying compound that targets Keap1 for degradation [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics; 2019 Oct 26-30; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2019;18(12 Suppl):Abstract nr B112. doi:10.1158/1535-7163.TARG-19-B112
Abstract B130: Elevated cancer-intrinsic type I interferon signaling confers a dependency on the RNA editor ADAR1
Authors: Gardino Alexandra K. , Collins Cindy , Lynes Maureen S. , Boriack-Sjodin P. Ann , Copeland Robert A. , Ribich Scott A.
Published: March 2020

The deamination of adenosine to inosine (known as A-to-I editing) is one of the most prevalent RNA modifications that occurs in metazoans and is mediated by the Adenosine Deaminase Acting on RNA (ADAR) family of enzymes. The enzyme ADAR/ADAR1 catalyzes the majority of A-to-I editing where it has been demonstrated to effect coding sequence, miRNA function and silencing of Alu repetitive elements1. A critical function of ADAR1 is to edit double stranded RNA (dsRNA) structures that can activate the cytoplasmic nucleoside sensors MDA5 and PKR, preventing aberrant activation of an innate immune type I interferon (IFN) response2,3. Consistent with this hypothesis, mutations in ADAR1 and other enzymes involved in nucleoside metabolism and/or sensing are found in Aicardi-Goutiéres Syndrome (AGS), an interferonopathy associated with spontaneous interferon production4. Through analysis of pooled CRISPR and shRNA screening data, we have identified that cancer cell lines with elevated expression of specific type I interferon stimulated genes (ISGs) are dependent on ADAR1 for their survival. Tumor cells can display elevated intrinsic type I interferon signaling and associated dsRNA burden due to multiple factors, including chronic cytoplasmic DNA activation of STING, oncovirus infection and other proinflammatory signals. We have identified a core subset of 26 ISGs that predict a cellular dependency on ADAR1 and demonstrate elevated expression of these ISGs in a diverse range of tumor types including head and neck squamous cell carcinoma, breast cancer, esophageal cancer, and lung cancer. Utilizing an isogenic cell line with low basal type I interferon signaling and knockout of ADAR1, we demonstrate that we can induce cell death through exogenous treatment with the dsRNA mimetic poly-(I:C) or type I interferons (IFNα or IFNβ) but not the type II interferon IFNγ. We believe that chronic ISG expression and dsRNA burden creates a dependency on ADAR1 to prevent activation of MDA5 and PKR. These data suggest an ADAR1 inhibitor could be beneficial for the treatment of tumors with elevated ISG expression.

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Citation Format: Alexandra K. Gardino, Cindy Collins, Maureen S. Lynes, P. Ann Boriack-Sjodin, Robert A. Copeland, Scott A. Ribich. Elevated cancer-intrinsic type I interferon signaling confers a dependency on the RNA editor ADAR1 [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics; 2019 Oct 26-30; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2019;18(12 Suppl):Abstract nr B130. doi:10.1158/1535-7163.TARG-19-B130
Abstract B131: CD73 as a new target for glioblastoma therapy
Authors: Teixeira Fernanda Cardoso , Azambuja Juliana H , Teixeira Helder F , BRAGANHOL ELIZANDRA
Published: March 2020

Glioblastoma (GB) is the most common malignant brain tumor and is characterized by high invasiveness, poor prognosis, and limited therapeutic options. Studies silencing the gene expression using interference RNA tool (siRNA) have been proposed as new alternative for cancer therapy. Here, we evaluated the potential of CD73 as a new therapeutic target, because it is overexpressed in solid tumors and emerges as a promising target to control GB progression. A cationic nanoemulsion (NE) as siRNA-CD73 delivery system was developed and its effect on glioma growth was determined. The nanostructured system was effective to complex the oligonucleotides for delivering on target cells. In addition, we observed that the NE-siRNA-CD73 complex was effective to reduce CD73 protein levels and AMPase activity which was further related to decreased in vitro C6 glioma cell viability. In addition, blockade of CD73 by NE-siRNA CD73 delayed in vivo tumor growth in a preclinical glioblastoma model by inducing apoptosis. Meanwhile, significantly reduced the population of lymphocytes, particularly Tregs, which could be associated to the antiglioma effect induced by the treatment. The data indicate the potential of siRNA-CD73 loaded cationic nanoemulsion as a therapeutic alternative to glioma treatment.

Citation Format: Fernanda Cardoso Teixeira, Juliana H Azambuja, Helder F Teixeira, ELIZANDRA BRAGANHOL. CD73 as a new target for glioblastoma therapy [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics; 2019 Oct 26-30; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2019;18(12 Suppl):Abstract nr B131. doi:10.1158/1535-7163.TARG-19-B131
Abstract B132: Inhibition of Haspin kinase to promote cell-intrinsic and extrinsic anticancer therapy
Authors: Melms Johannes C. , Vallabhaneni Sreeram , Mills Caitlin E. , Wucherpfennig Kai , Sorger Peter K. , Izar Benjamin
Published: March 2020

Oncogene-targeted therapies are initially effective in most patients with BRAF-mutated melanoma. However, patients frequently develop resistance during therapy. At the time of therapy resistance, they are also less likely to respond to immune checkpoint inhibitors (ICI) with response rates ranging from 0-12%, compared to 40-60% when used in the first line. This may be in part be due to rapid tumor growth that outpaces pharmacodynamics of ICI. New drugs that directly control tumor growth and effectively enhance ICI activity are therefore needed. We report that the small molecule CX-6258 has potent activity against both RAF/MEK inhibitor (RMS) and resistant (RMR) BRAF-mutant melanoma cell lines. CX-6258 is annotated as a pan-PIM kinase inhibitor, with an EC50 corrected for growth rate (GR50) of ~200 nM; in contrast, other PIM inhibitors had no in vitro activity, suggesting that PIMs may not be the true target in melanoma - we therefore sought to systematically study the targets of this compound. Using an unbiased kinase profiling approach, we identified Haspin Kinase (HASPIN) as the key target of CX-6258 with an IC50~10nM. Haspin kinase (Haspin) is a poorly understood mitotic kinase, whose only well-defined function is phosphorylation of Histon H3 at Thr3 (pH3T3). Treatment with CX-6258 resulted in reduced proliferation, reduced phosphorylation of pH3T3, frequent formation of micronuclei (MN), recruitment of cGAS and activation of the cGAS-STING-pathway. By using CRISPR/CAS9 knock outs of PIM kinase we show that these targets are not required for CX-6258 function. Furthermore, siRNA mediated knock-down of HASPIN phenocopied CX-6258. In murine models, CX-6258 induces a potent cGAS dependent type-I-interferon response in tumor cells, increases IFNγ-producing CD8+ T-cells, reduces Tregs, and enhances responses to ICIs in vivo. HASPIN is more strongly expressed in malignant compared to healthy tissue and its inhibition by CX-6258 has minimal toxicity in ex vivo expanded human tumor-infiltrating-lymphocytes (TILs) and in vitro differentiated human neurons, suggesting a potential therapeutic index for anti-cancer therapy. CX-6258 also shows activity in several Ewing sarcoma and multiple myeloma cell lines with. In summary, HASPIN inhibition may overcome drug resistance in melanoma, synergize with ICIs and target a vulnerability in different cancer lineages.

Citation Format: Johannes C. Melms, Sreeram Vallabhaneni, Caitlin E. Mills, Kai Wucherpfennig, Peter K. Sorger, Benjamin Izar. Inhibition of Haspin kinase to promote cell-intrinsic and extrinsic anticancer therapy [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics; 2019 Oct 26-30; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2019;18(12 Suppl):Abstract nr B132. doi:10.1158/1535-7163.TARG-19-B132
Abstract B144: Lack of immunotherapy efficacy in a syngeneic bone metastasis model of triple-negative breast cancer
Authors: Kähkönen Tiina E , Suominen Mari I , Mäki-Jouppila Jenni HE , Halleen Jussi M , Bernoulli Jenni
Published: March 2020

Background: Triple-negative breast cancer (TNBC) is an aggressive cancer with treatment options limited to standard-of-care chemotherapy. TNBC patients develop metastases in high incidence, and almost all patients have bone metastases at end-stage disease. Bone metastases are mainly osteolytic, causing severe bone loss that can be prevented by bone-targeted agents. Currently, there is no efficient cure for bone metastases. Activation of the patient’s own immune system by immunotherapies is widely studied in various cancers, but their efficacy on bone metastases is not well established. In this study, we aimed to evaluate the efficacy of immunotherapies in comparison to standard-of-care compounds in a preclinical TNBC bone metastasis model. Materials and methods: Mouse 4T1-GFP TNBC cells were inoculated intracardially to immunocompetent female Balb/c mice to model bone metastasis. Treatment of single agents of chemotherapy (cyclophosphamide, 100 mg/kg), bone-targeting agent (zoledronic acid, 0.1 mg/kg), and immunotherapies programmed cell death 1 antibody (mouse anti-PD-1, 10 mg/kg) and indoleamine-pyrrole 2,3-dioxygenase (IDO) inhibitor (epacadostat, 100 mg/kg), and the combination of anti-PD-1 and epacadostat were started on the day following the cancer cell inoculations. The study was terminated 12-13 days after the inoculations. Tumor burden was evaluated by GFP imaging and tumor-induced bone loss by X-ray imaging at sacrifice. Tumor infiltrating lymphocytes (TILs) were evaluated by immunohistochemical stainings of CD3+, CD4+ and CD8+ T cells. Results: Cyclophosphamide decreased skeletal tumor burden and the area of tumor-induced osteolytic bone lesions. Zoledronic acid decreased the area of osteolytic lesions but had no effect on skeletal tumor burden. Anti-PD-1, epacadostat and their combination had no effect on skeletal tumor burden or in the development of osteolytic lesions. Low number or no TILs were observed in the tumors growing in bone obtained from vehicle-treated mice. Conclusions: Immunotherapies did not prevent tumor growth in bone or tumor-induced bone changes in the syngeneic TNBC model. This is probably caused by the low number of TILs in the tumors growing in bone. Further studies are needed to evaluate the effects of treatment combinations and to increase the responsiveness to immunotherapies especially in bone metastases.

Citation Format: Tiina E Kähkönen, Mari I Suominen, Jenni HE Mäki-Jouppila, Jussi M Halleen, Jenni Bernoulli. Lack of immunotherapy efficacy in a syngeneic bone metastasis model of triple-negative breast cancer [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics; 2019 Oct 26-30; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2019;18(12 Suppl):Abstract nr B144. doi:10.1158/1535-7163.TARG-19-B144
Abstract C013: HI-B9 suppresses colorectal cancer by inhibiting Wnt/β-catenin pathway
Authors: Shin Seung Ho , Reddy Kanamata , Dong Zigang
Published: March 2020

Deregulated Wnt/β-catenin pathway plays an important role in colorectal cancer. β-Catenin interacts with transcription factor 7-like 2 (TCF7L2 or TCF4) to express oncogenes including c-myc, axin2 and cyclin D1. Here we describe a small molecule, referred to as HI-B9, which inhibits the growth of colorectal cancer cell lines. HI-B9 suppressed tryptophan fluorescence of β-catenin that contains TCF4-binding residues. In silico docking of HI-B9 on β-catenin showed a binding mode that blocks Lys 312 residue which is critical for the interaction between β-catenin and its interactors. A binding assay showed that the binding affinity of HI-B9 against β-catenin G307A/K312E mutant was significantly reduced compared to that against wildtype. HI-B9 inhibited β-catenin/TCF4 luciferase activity in a dose-dependent manner. Anchorage-independent growth of HCT116 and HT29 colorectal cancer cells were suppressed by the small molecule. mRNA expression levels of Wnt target genes were reduced by HI-B9 treatment. HI-B9 did not affect the translocation of β-catenin toward the nucleus. The therapeutic effects of HI-B9 was due to the disruption of β-catenin/TCF4 complex formation ex vivo. Our findings demonstrate the therapeutic potential of HI-B9 against colorectal cancer with aberrant Wnt/β-Catenin signaling pathway.

Citation Format: Seung Ho Shin, Kanamata Reddy, Zigang Dong. HI-B9 suppresses colorectal cancer by inhibiting Wnt/β-catenin pathway [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics; 2019 Oct 26-30; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2019;18(12 Suppl):Abstract nr C013. doi:10.1158/1535-7163.TARG-19-C013
Abstract C016: Oxidative phosphorylation is a metabolic vulnerability in chemotherapy resistant triple negative breast cancer
Authors: Evans Kurt , Moulder Stacy , Yuca Erkan , Scott Stephen , Arango Natalia Paez , Shariati Maryam , Vellano Christopher P , Saridogan Turcin , Zheng Xiaofeng , Gonzalez-Angulo Ana Maria , Zhao Ming , Su Xiaoping , Tapia Coya , Chen Ken , Akcakanat Argun , Perou Charles M , Lim Bora , Tripathy Debu , Yap Timothy A , Francesco Maria E Di , Draetta Giulio , Jones Philip , Marszalek Joe , Meric-Bernstam Funda
Published: March 2020

There is a pressing need to identify improved therapies for triple negative breast cancers (TNBC) resistant to standard chemotherapy. To identify potential molecular targets, we performed RNA sequencing of pre-treatment biopsies from 43 patients with operable TNBC who received neoadjuvant anthracycline and taxane-based chemotherapy. Ingenuity pathway analysis demonstrated that the top canonical pathway associated with higher likelihood of recurrence was higher expression of oxidative phosphorylation (OXPHOS) signature. We therefore sought to determine the efficacy of IACS-10759, a potent inhibitor of OXPHOS, in 10 TNBC patient-derived xenografts (PDX), 8 generated from chemotherapy-resistant tumors. Partial response was observed in one PDX model and prolonged disease stabilization in 5 of 10 PDXs. PDXs with higher expression of protein coding mitochondrial genes were more sensitive to IACS-10759. AXL overexpression was associated with intrinsic and acquired IACS-10759 resistance. The combination of cabozantinib, a multi-kinase inhibitor targeting AXL, with IACS-10759 significantly improved responses in TNBC PDXs. In contrast, selective AXL inhibitor BGB324 or knockdown of AXL did not enhance IACS-10759 sensitivity. In addition, an in vivo synthetic lethality screen identified CDK4, PARP1 and PARP2 as potential combination targets for IACS-10759. Palbociclib as well as talazoparib enhanced growth inhibitory effect of OXPHOS inhibition in vitro and in vivo. Our data suggests that OXPHOS is a promising target in chemoresistant TNBC. IACS-10759 is currently in Phase 1 testing, including TNBC. Further work is needed to determine the optimal biomarker-driven combination partners.

Citation Format: Kurt Evans, Stacy Moulder, Erkan Yuca, Stephen Scott, Natalia Paez Arango, Maryam Shariati, Christopher P Vellano, Turcin Saridogan, Xiaofeng Zheng, Ana Maria Gonzalez-Angulo, Ming Zhao, Xiaoping Su, Coya Tapia, Ken Chen, Argun Akcakanat, Charles M Perou, Bora Lim, Debu Tripathy, Timothy A Yap, Maria E Di Francesco, Giulio Draetta, Philip Jones, Joe Marszalek, Funda Meric-Bernstam. Oxidative phosphorylation is a metabolic vulnerability in chemotherapy resistant triple negative breast cancer [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics; 2019 Oct 26-30; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2019;18(12 Suppl):Abstract nr C016. doi:10.1158/1535-7163.TARG-19-C016
Abstract C046: A Smo inhibitor DCBCO1303 with potent Hedgehog signaling pathway antagonist activity is highly active in animal tumor model of medulloblastoma and cholangiocarcinoma
Authors: Lee Ying-Shuan E , Kuo Mann-Yan , Tsai Pei-Yi , Liu Chia Wei , Wei Win Yin
Published: March 2020

The hedgehog (Hh) pathway is a critical embryonic signaling cascade regulating cell growth, proliferation and differentiation. Hh signaling is significantly less active in adult tissues, where its primary role appears to be the maintenance of stem cell populations in skin and the central nervous system. Smoothened (Smo), a 7-pass transmembrane receptor with a GPCR-like structure, is a key component of the Hh signaling pathway, the activity of which is suppressed by the 12-pass transmembrane protein Patched (Ptch). Therefore, components of the Hh pathway (such as Shh, SMO, and GLI1/2) are viable therapeutic targets for anti-tumor strategy. We report here the in vivo effects of a potent Smo antagonist DCBCO1303 for the treatment of medulloblastoma and cholagiocarcinoma animal tumor model. DCBCO1303 demonstrated Hh signaling pathway antagonist activity in a 293 cell-based Gli-luciferase inhibition assay upon agonist treatment (IC50 = 3.5 nM), and retains inhibition activity against the Smo wild-type and D473H mutant responsible for resistance to GDC-0449 in medulloblastoma patients with IC50 of 5.1 and 43.7nM, respectively. DCBCO1303 potently suppress Gli1 expression in HEPM cells with IC50 of 2.3 nM. Treatment of a medulloblastoma allograft model with daily oral dosing from 1.25 to 40 mg/kg of DCBCO1303 for 10 days leads to dose responsive antitumor activity with tumor regressions occurring at 40 mg/kg.(Gli 1 mRNA inhibition correlated with tumor growth inhibition). DCBCO1303 was also highly efficacious against the growth of cholangiocarcinoma xenograft tumors. The DCBCO1303 can therefore be evaluated further and serve as a drug development candidate for treatment of Hh pathway-driven cancers.

Citation Format: Ying-Shuan E Lee, Mann-Yan Kuo, Pei-Yi Tsai, Chia Wei Liu, Win Yin Wei. A Smo inhibitor DCBCO1303 with potent Hedgehog signaling pathway antagonist activity is highly active in animal tumor model of medulloblastoma and cholangiocarcinoma [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics; 2019 Oct 26-30; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2019;18(12 Suppl):Abstract nr C046. doi:10.1158/1535-7163.TARG-19-C046
Abstract C063: A novel Nrf2 inhibitor suppresses proliferation and enhances the sensitivity of cancer cells to chemotherapy
Authors: Zhang Di , Aldrich Kelly , Dexheimer Thomas , Ellsworth Edmund , Odom Aaron , Liby Karen
Published: March 2020

The Nrf2-Keap1-ARE pathway, a master defense mechanism against oxidative and electrophilic stresses, has emerged as a target for cancer therapy. Activation of Nrf2 has been a common strategy for cancer prevention, as Nrf2 deficiency enhances susceptibility to carcinogens in a wide variety of preclinical models. However, accumulating evidence suggests a tumor-promoting role for Nrf2 in established tumors. Constitutive activation of Nrf2 because of gain of functionmutations in NFE2L2 or loss of function mutations in its negative regulator Keap1, has been found in many cancers, especially lung cancer, and is associated with chemoresistance and poor survival in human patients. Nrf2 inhibitors, therefore, provide a potential novel strategy for treating cancer. Here, we report a novel Nrf2 inhibitor, MSU225, identified from an existing chemistry library. MSU225 dose-dependently downregulated tBHQ (tert-butyl hydroquinone)-induced Nrf2 transcriptional activity in a luciferase reporter assay without cytotoxicity. MSU225 also decreased the expression of Nrf2 downstream targets, including HO-1, NQO1, GST1A1, GCLC, GCLM, and UGT1A6 in A549 human lung cancer cells, in which Keap1 is mutated and Nrf2 activation is constitutive. Notably, MSU225 induced a striking and significant (p<0.05) decrease of Nrf2 protein in A549 cells. The effect of MSU225 on Nrf2 protein levels can be blocked with the proteasome inhibitor MG132, suggesting MSU225 enhances Nrf2 degradation through the proteasome system. Ubiquitination of Nrf2 was also increased after MSU225 treatment. Interestingly, MSU225 also decreased Nrf2 protein levels in Keap1 knockout and βTrCP knockout cells, which are the two major pathways inducing Nrf2 degradation. Nrf2 involvement in cancer cell proliferation is well known. MSU225 inhibited the growth of human lung cancer cells (A549, H460, A427) in both 2D cell culture and soft agar. Cells addicted to Nrf2 were more susceptible to MSU225 suppression of cell proliferation than cells not addicted to Nrf2. MSU225 also sensitized A549 cells to chemotherapies including doxorubicin, carboplatin, 5-fluorouracil and Topotecan. Our results suggest that MSU225 is a novel Nrf2 inhibitor that enhances the degradation of Nrf2 in a Keap1 and βTrCP independent manner. In vivo studies to assess the efficacy of MSU225 for treating experimental lung cancer are ongoing.

Citation Format: Di Zhang, Kelly Aldrich, Thomas Dexheimer, Edmund Ellsworth, Aaron Odom, Karen Liby. A novel Nrf2 inhibitor suppresses proliferation and enhances the sensitivity of cancer cells to chemotherapy [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics; 2019 Oct 26-30; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2019;18(12 Suppl):Abstract nr C063. doi:10.1158/1535-7163.TARG-19-C063
Abstract C066: BT5528, a Bicycle Toxin Conjugate targeting EphA2: mechanism of action and clinical translation
Authors: Bennett Gavin , Brown Amy , Mudd Gemma , Lahdenranta Johanna , Keen Nicholas
Published: March 2020

BT5528 is a Bicycle Toxin Conjugate (BTC) in which an EphA2 binding peptide (a Bicycle®) is conjugated through an inert sarcosine spacer chain, and a cleavable linker, to the antimitotic toxin MMAE. Increased EphA2 expression has been reported in multiple tumor types (including NSCLC, ovarian cancer, TNBC, gastric/upper GI, pancreatic and urothelial cancers) and so represents a attractive tumor binding target. The identification, characterization and initial in vivo profiling of BT5528 has previously been described. This abstract describes a more detailed analysis of the mechanism of action of BT5528. Dosing of BT5528 on a once weekly schedule is efficacious in a range of tumour models. Observed anti-tumor activity is closely related to the level of EphA2 expression on tumor cells ranging from complete responses in EphA2 positive models to minimal activity in EphA2 low/null models. Efficacy of BT5528 is also seen in a number of “hard to hit” models including large (~1000mm3) patient derived xenograft models (PDX) including highly-resistant models and PDX models of pancreatic ductal adenocarcinoma. We also demonstrate the utility of BT5528 in disseminated disease in an EphA2 positive model of bone metastasis. Efficacy of BT5528 is seen even when dosed as infrequently as every 2 weeks and is not dependent on infusion duration allowing for flexible drug administration schedule. Additionally, we demonstrate the significance of the BT5528 bystander effect to anti-tumor activity using versions of BT5528 with non-releasable payload as well as non-cell permeable payload. Efficacy of BT5528 is also seen in a number of “hard to hit” models including large (~1000mm3) PDX, highly-resistant models, models of pancreatic cancer, and models of metastatic disease. Importantly, BT5528 can produce this profound efficacy without the bleeding and coagulation toxicity seen with previous ADC approaches to this target. The overall profile of BT5528 provides a highly differentiated approach to targeting EphA2, offering the potential for profound efficacy in a range of solid tumours. IND-enabling activities are underway, with clinical trials expected to start later this year.

Citation Format: Gavin Bennett, Amy Brown, Gemma Mudd, Johanna Lahdenranta, Nicholas Keen. BT5528, a Bicycle Toxin Conjugate targeting EphA2: mechanism of action and clinical translation [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics; 2019 Oct 26-30; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2019;18(12 Suppl):Abstract nr C066. doi:10.1158/1535-7163.TARG-19-C066