bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 1656: First-in-class, fluorinated folate receptor specific agents that target tumor cells via inhibition of serine hydroxymethyltransferase 2 (SHMT2) and 5-aminoimidazole-4-carboxamide formyltransferase (AICARFTase)
Authors: Nayeen Md Junayed , Shah Khushbu , Gangjee Aleem , Dekhne Aamod , Hou Zhanjun , Matherly Larry H.
Published: August 2018

Tumor-specific folate receptor (FR) targeting over the ubiquitous reduced folate carrier (RFC) allows for specific tumor targeting without the attending dose-limiting toxicity of all clinically used cytotoxic agents. In an attempt to provide selectivity for FRα and/or β, folic acid has been conjugated with a variety of cytotoxic payloads to alleviate dose-limiting toxicities since folic acid is not transported via RFC (the major tissue folate transporter) to any significant extent. These conjugates have been unsuccessful in clinical trials likely in part due to the instability of the linkers used for conjugation. Premature cleavage results in the cytotoxic component being released prior to tumor penetration, thus precluding any possibility of selective tumor targeting. We designed novel pyrrolo[3,2-d]pyrimidine compounds in which both the targeting component and the cytotoxic component are in the same molecule. These compounds do not require any conjugation or linkers and hence do not suffer any premature cleavage. In this report, we synthesized and evaluated a “first-in-class” series of fluorinated analogues that target FRα/β and have limited transport via RFC, thus providing selectivity for tumors expressing FRα and/or FRβ. Two lead molecules, AGF347 and AGF355, were potent inhibitors of KB human tumor cell proliferation in vitro (IC50 = 1.05 nM and 6.25 nM respectively). Based on protection experiments with glycine, thymidine, adenosine and 5-aminoimidazole-4-carboxamide (AICA), AGF347 and AGF355 were identified as dual inhibitors of serine hydroxymethyltransferase 2 (SHMT2), a key enzyme in mitochondrial one-carbon metabolism and reported oncodriver, and AICA ribonucleotide formyltransferase (AICARFTase), the 2nd folate-dependent step in de novo purine biosynthesis. These compounds are currently being evaluated in preclinical studies as potential candidates for clinical trials.

Citation Format: Md Junayed Nayeen, Khushbu Shah, Aleem Gangjee, Aamod Dekhne, Zhanjun Hou, Larry H. Matherly. First-in-class, fluorinated folate receptor specific agents that target tumor cells via inhibition of serine hydroxymethyltransferase 2 (SHMT2) and 5-aminoimidazole-4-carboxamide formyltransferase (AICARFTase) [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 1656.
Abstract 1662: Synthesis and biologic evaluation of diethylbenzaldehyde analogues to probe functional activity of aldehyde dehydrogenase activity in cancer
Authors: Ibrahim Ali , Sadiq Maria , Presa Daniela , Ntafoulis Ioannis , Alkawi Ahmad , Frame Fiona , Maitland Norman J. , Cournia Zoe , Loadman Paul M. , Moreb Jan , Pors Klaus
Published: August 2018

The human aldehyde dehydrogenases (ALDHs) play a major role in detoxifying highly reactive aldehydes into carboxylic acids. Deregulation of ALDHs has implications in a number of cancers. They play an important role as a cancer stem cell (CSC) marker due to high activity found in CSCs, while high expression is also known to lead to resistance to chemotherapeutic drugs. Although the exact roles of ALDHs are not fully understood, emerging information indicates several isoforms from the ALDH1 family, ALDH3A1 and ALDH7A1, play key roles in several cancer types. To probe the role of ALDH functional activity, we here report on the perturbation of ALDH expression and function using diethylbenzaldehyde (DEAB) analogues. The H1299 lung cancer cell line has negligible amount of ALDH activity, and ALDH-expressing variants were used to study the novel DEAB analogues. H1299 wild-type cells (WT) and cells expressing RFP were used as controls. Expression of the proteins was confirmed by Western blots and ALDH enzymatic activity assay. We used cell culture, colorimetric MTT assay, aldefluor assay and in vitro treatment with DEAB analogues. ALDH-expressing lysates were used to obtain biochemical inhibition data of the DEAB analogues using propionaldehyde as substrate with NAD+ as a co-factor. DEAB has been shown to covalently bind to ALDH7A1, and computational modeling was employed to understand how chemical modifications to DEAB affected the binding mode. Selected ALDH-affinic probe compounds were tested in a panel of colon, lung and prostate cancer cell lines including docetaxel-resistant variant and patient samples to investigate if DEAB analogues had an effect on cell viability as single agents or in combination with docetaxel. In conclusion, the novel DEAB analogues aid us to understand ALDH functional activity and provide a platform for discovering more selective ALDH inhibitors

Citation Format: Ali Ibrahim, Maria Sadiq, Daniela Presa, Ioannis Ntafoulis, Ahmad Alkawi, Fiona Frame, Norman J. Maitland, Zoe Cournia, Paul M. Loadman, Jan Moreb, Klaus Pors. Synthesis and biologic evaluation of diethylbenzaldehyde analogues to probe functional activity of aldehyde dehydrogenase activity in 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 1662.
Abstract 1664: 4-Bromophenylhydrazinyl benzenesulfonylphenylureas inhibit indoleamine 2,3-dioxygenase in vitro and in vivo
Authors: Ueng Shau-Hua , Kuo Ching-Chuan , Lin Shu-Yu , Yeh Teng-Kuang , Song Jen-Shin , Hung Ming-Shiu , Chen Chiung-Tong
Published: August 2018

Indoleamine 2,3-dioxygenase has been considered as a promising anti-cancer drug target. Several pharmaceutical companies, including Pfizer, Merck, and Bristol-Myers Squibb, are known to be in pursuit of IDO inhibitors, and Incyte recently reported good results in the phase II clinical trial of the IDO inhibitor Epacadostat. In previous work, we developed a series of IDO inhibitors based on a high-throughput screening core structure, sulfonylhydrazide. Further, we developed the 4-bromophenylhydrazinyl benzenesulfonylphenylurea, as a potent IDO inhibitor with an IC50 value within 100 nM in inhibiting IDO in vitro. This compound demonstrated a 30% reduction in tumor weight in a murine CT26 syngeneic model on day 18 with 100 mg/kg oral administration twice daily, indicating that the 4-bromophenylhydrazinyl benzenesulfonylphenylurea may have potential for further investigation in the development of anti-tumor drugs.

Citation Format: Shau-Hua Ueng, Ching-Chuan Kuo, Shu-Yu Lin, Teng-Kuang Yeh, Jen-Shin Song, Ming-Shiu Hung, Chiung-Tong Chen. 4-Bromophenylhydrazinyl benzenesulfonylphenylureas inhibit indoleamine 2,3-dioxygenase in vitro and in vivo [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 1664.
Abstract 1673: Ras degrading small molecules inhibit the transformation of colorectal cancer cells independently of beta-catenin signaling
Authors: Hwang Jeong-Ha , Ro Eun Ji , Shin Wookjin , Choi Kang-Yell
Published: August 2018

Development of drugs controlling Ras is an emerging issue in cancer therapy; however, no clinically applicable drug is currently available. On the basis of the mechanism of Ras protein stability regulation via the Wnt/β-catenin signaling pathway, we previously identified small molecules inhibiting the proliferation and transformation of various colorectal cancer (CRC) cells via degradation of both β-catenin and Ras. Due to the absence of Ras degradation in cells expressing non-degradable mutation in β-catenin, and the need to determine an alternative mechanism for Ras degradation, we established a cell-based system to screen compounds that degrade Ras independently of the Wnt/β-catenin signaling pathway. A cell-based high-content screening (HCS) system monitoring the level of EGFP-K-RasG12V was established using HCT-116 cells harboring a non-degradable mutant β-catenin (ΔS45). Through HCS of a chemical library composed of 10,000 compounds, and by subsequent characterization of candidate compounds, we identified several compounds that degraded Ras without affecting β-catenin levels. KY7749, the most effective compound, inhibited the proliferation and transformation of CRC cells, including those resistant to the EGFR monoclonal antibody, cetuximab, due to KRAS mutations. Small molecules that degrade Ras independently of β-catenin would be a potential treatments for cancers caused by aberrant EGFR, Ras, and β-catenin.

Citation Format: Jeong-Ha Hwang, Eun Ji Ro, Wookjin Shin, Kang-Yell Choi. Ras degrading small molecules inhibit the transformation of colorectal cancer cells independently of beta-catenin signaling [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 1673.
Abstract 1674: Novel direct AMPK activator suppresses non-small cell lung cancer through inhibition of lipid metabolism
Authors: Chen Xi , Xie Chun , Fan Xing Xing , Jiang Ze Bo , Wong Vincent , Xu Jia Hui , Yao Xiao Jun , Liu Liang , Leung Elaine L.
Published: August 2018

Lung cancer is the leading cause of cancer mortality. While non-small cell lung cancer (NSCLC) is the most common histological type of lung cancer and dominates almost 85% of all lung cancer cases. Conventional therapy, such as surgery, chemotherapy, or radiotherapy, scarify normal cells during the curing progress are becoming unfavorable. To avoid harmful side-effect on normal cell, target-based therapy is the mainstream of modern cancer therapy. For example, gefitinib is a clinically-marketed drug which acts as tyrosine kinase inhibitor to inhibit epidermal growth factor receptor (EGFR) activating signaling pathway. For the NSCLC patients who harbor activating substitution from leucine to arginine at amino acid 858 (L858R) point mutation and in-frame exon 19 deletion on EGFR, response well to gefitinib and these two common mutation are used a biomarkers for gefitinib prescription. However, gefitinib-resistance commonly happens due to further substitution mutation from threonine to methionine at amino acid position 790 (T790M) occurred after one year or less gefitinib treatment. Therefore, developing new treatment strategy to tackle gefitinib-resistance is urgently. Abnormal energy metabolism is accepted as new cancer hallmark. Recently, a metabolism rate-limiting enzyme 5'-adenosine menophosphate-activated protein kinase (AMPK) has become a promising anti-cancer target. In this study, we have applied computational docking to perform in silico virtual screening, and we have identified a novel direct AMPK agonist, D561-0775 from a compound library. Using enzyme activation assay, we demonstrated that D561-0775 activates directly on AMPK α subunit. In addition, D561-0775 exhibited significant inhibitory effect on gefitinib-resistant NSCLC cell lines but is less cytotoxicity on normal lung fibroblast cells. D561-0775 also activates AMPK/mTOR signaling pathway, resulting in induction of apoptosis, cell cycle arrest, suppressing glycolysis and cholesterol synthesis in gefitinib-resistant H1975 lung cancer cells. Taken together, D561-0775 has provided clue on a new chemical structure that could be developed as cancer drug for gefitinib-resistant NSCLC patients through inhibition lipid metabolism by directly targeting at AMPK directly. Acknowledgments: This work was supported by Macau Science and Technology Development Fund (Project No: 021/2013/A1, 074/2011/A3 & 082/2013/A3)

Citation Format: Xi Chen, Chun Xie, Xing Xing Fan, Ze Bo Jiang, Vincent Wong, Jia Hui Xu, Xiao Jun Yao, Liang Liu, Elaine L. Leung. Novel direct AMPK activator suppresses non-small cell lung cancer through inhibition of lipid metabolism [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 1674.
Abstract 168: Cancer stem-like properties and drug resistance are dependent on purine synthetic metabolism mediated by the mitochondrial enzyme MTHFD2
Authors: Gotoh Noriko , Nishimura Tatsunori , Nakata Asuka , Horike Shin-ichi , Kohno Susumu , Takahashi Chiaki , Soga Tomoyoshi , Tojo Arinobu
Published: August 2018

Tumor recurrence is attributable to cancer stem-like cells (CSCs), the metabolic mechanisms of which currently remain obscure. Here, we uncovered the critical role of folate-mediated one-carbon (1C) metabolism involving mitochondrial methylenetetrahydrofolate dehydrogenase 2 (MTHFD2) and its downstream purine synthesis pathway. MTHFD2 knockdown greatly reduced tumorigenesis and stem-like properties, which were associated with purine nucleotide deficiency, and caused marked accumulation of 5-aminoimidazole carboxamide ribonucleotide (AICAR)—the final intermediate of the purine synthesis pathway. Lung cancer cells with acquired resistance to the targeted drug gefitinib exhibited increased stem-like properties and enhanced expression of MTHFD2. MTHFD2 knockdown or treatment with AICAR reduced the stem-like properties and restored gefitinib sensitivity in gefitinib-resistant cancer cells. Thus, MTHFD2-mediated mitochondrial 1C metabolism appears critical for cancer stem-like properties and resistance to drugs including gefitinib through consumption of AICAR, leading to depletion of the intracellular pool of AICAR. Because CSCs are dependent on MTHFD2, therapies targeting MTHFD2 may eradicate tumors and prevent recurrence.

Citation Format: Noriko Gotoh, Tatsunori Nishimura, Asuka Nakata, Shin-ichi Horike, Susumu Kohno, Chiaki Takahashi, Tomoyoshi Soga, Arinobu Tojo. Cancer stem-like properties and drug resistance are dependent on purine synthetic metabolism mediated by the mitochondrial enzyme MTHFD2 [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 168.
Abstract 1682: Combined treatment of aldose reductase inhibitor, fidarestat, and anti-PD1 antibodies synergistically prevents T cell- and NK cell-mediated colon cancer growth in murine models
Authors: Saxena Ashish , Sonowal Himangshu , Srivastava Satish K. , Ramana Kota V.
Published: August 2018

Immune checkpoint inhibitors such as anti-programmed death 1 (PD1) and anti-PD-L1 monoclonal antibodies though have great potential for cancer immunotherapy, the acquired drug resistance and unwanted immune side effects limit their use. However, the combination therapy using conventional drugs and immune checkpoint inhibitors not only synergistically increase anti-tumor responses but it also reduces immune-associated adverse events. In our earlier studies, we have shown that inhibition of polyol pathway enzyme, aldose reductase (AR) prevents colon cancer growth and metastasis in culture as well as in mouse models. In this study, we investigated whether fidarestat, a potent AR inhibitor that has already gone through Phase-III clinical trial for diabetic neuropathy and found to safe for human use, can synergize with anti PD-1 to increase antitumor activity and decrease immune-associated adverse effects. Mice bearing syngeneic CT26 colon carcinoma tumors were treated with anti PD-1 alone or in combination with fidarestat, and the tumor growth was monitored. Our results indicate that fidarestat in combination with anti-PD1 synergistically increases tumor regression within 28 days of treatment. Further, a combination of fidarestat and anti-PD1 significantly increased the CD8+ T cells and natural killer (NK) cells and decreased the Myeloid-derived suppressor cells (MDSCs) at tumor milieu. Fidarestat plus anti-PD1 also increased CD8+ T cell and NK cell effector functions as determined by IFNg and granzyme B. Systemically, combination therapy also increased the number of CD8+ T cells and NK cells and decreased MDSCs in the mouse spleens. Further, the effector functions of CD8+ T cells and NK cells were increased with the combination treatment in mice spleens. Moreover, the levels of various inflammatory cytokines and chemokines in the serum and liver were significantly less in fidarestat plus anti-PD1 -treated mice as compared to anti-PD1 alone -treated mice indicating that fidarestat rescues immune-mediated adverse events in various organs. Thus, our results suggest that by regulating the number as well as effector function of CD8+ T cells, NK cells and MDSCs, AR inhibitor in combination with anti-PD1 would not only regress the tumor growth but would also provide a long-lasting specific immunity against colon cancer, which would decrease the chances of tumor recurrence.

Citation Format: Ashish Saxena, Himangshu Sonowal, Satish K. Srivastava, Kota V. Ramana. Combined treatment of aldose reductase inhibitor, fidarestat, and anti-PD1 antibodies synergistically prevents T cell- and NK cell-mediated colon cancer growth in murine 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 1682.
Abstract 1685: Genomics based studies of gastric tumors identify ICOS as potential target for therapeutic intervention
Authors: Hirsch Heather A. , Reeves Jason , Zi Tong , Needham Alexander , Stack Edward , Lee David , Lees Emma , Law Deborah A. , Trehu Elizabeth
Published: August 2018

JTX-2011, an ICOS agonist antibody, is the first clinical program to emerge from Jounce's Translational Science Platform, which couples the choice of target mechanism to potential predictive biomarkers of response. ICOS (Inducible T cell CO-Stimulator), a co-stimulatory molecule expressed primarily on T lymphocytes, was prioritized as a target based on preclinical and clinical data suggesting that it plays an important role in the immune response to cancer. Fundamental data from our preclinical studies shows that tumor reduction occurs only in animals when a certain percentage of ICOS positive immune cells are resident within the tumor or in combination with a PD-1 inhibitor. Thus ICOS expression is a key element of our biomarker-driven approach in the ICONIC clinical trial. Based on this biomarker approach, we have identified gastric cancer as a cancer of potential interest for an ICOS-targeted immunotherapy approach.

Gastric adenocarcinoma was identified as a tumor of interest based on the integrated analysis of RNA, DNA and clinical data from the Cancer Genome Atlas (TCGA). This analysis was performed within stomach adenocarcinoma (STAD) to understand the context in which ICOS is expressed. ICOS levels were correlated to gene signatures of immune infiltrate as well as other clinical attributes and molecular markers. ICOS and PD-L1 levels were assessed by IHC in human tumor samples and in biopsies from ICONIC participants.IHC and RNA analyses reveals a dynamic range of ICOS expression across gastric adenocarcinoma tumors, with high prevalence in both EBV+ and MSI-H tumors as well as a subset of EBV-/MSS tumors. While there is a correlation between ICOS, ICOS signature, PD-L1 and IFNγ signatures, RNA analysis indicates that a subpopulation of gastric tumors with lower levels of PD-L1 expression may be ICOS positive. Integrative analysis of tumors identifies gastric cancer as an attractive indication for exploration of JTX-2011 plus a PD-1 inhibitor based on the relatively high frequency of ICOS expression within this tumor type. Since ICOS expression has a dynamic range of expression, an ICOS IHC biomarker is being used to enrich for patients in a gastric cancer cohort, as well as other tumor-specific cohorts in the Phase 2 portion of the ICONIC clinical study.

Citation Format: Heather A. Hirsch, Jason Reeves, Tong Zi, Alexander Needham, Edward Stack, David Lee, Emma Lees, Deborah A. Law, Elizabeth Trehu. Genomics based studies of gastric tumors identify ICOS as potential target for therapeutic intervention [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 1685.
Abstract 1696: Glycogen synthase kinase (GSK-3) inactivation downregulates PD-1 and synergizes with PD-1/PL1 and CTLA-4 blockade in cancer immunotherapy
Authors: Rudd Christopher E.
Published: August 2018

Immune checkpoint blockade (ICB) of negative co-receptors on T-cells such as cytotoxic T-cell antigen-4 (CTLA-4) and programmed cell death-1 (PD-1) is a promising approach for the treatment of cancer. Despite this success, the poor prognosis for most patients continues to highlight a need for developing novel clinical interventions. In this context, we identified the enzyme glycogen synthase kinase-3 (GSK-3) as the major regulator of PD-1 expression on T-cells (Taylor et al., 2016 Immunity). We have shown that small molecule inhibitors (SMIs) of GSK-3 are as effective as anti-PD-1 in controlling the growth of B16 melanoma, or EL4 lymphoma, in primary tumor and metastatic settings (Taylor et al., 2017 Can Res; Krueger and Rudd, Immunity 2017). At the same time, the fact that GSK-3 inactivation up-regulates transcription factor T-bet which upregulates interferon gamma (IFNγ) and granzyme B (GZMB) suggested that GSK-3 inactivation might provide extra value beyond of its down-regulation of PD-1. Here, we show that GSK-3 SMIs can synergize with anti-PD-1 and anti-CTLA-4 to eliminate B16 solid tumors that are otherwise resistant to anti-PD-1, or anti-CTLA-4 inhibition alone. At a cellular level, GSK-3 inactivation preferentially down-regulated PD-1 on CD8+ tumor infiltrating T-cells, while at a molecular level, GSK-3 SMIs inhibited PD-1 transcription, increased granzyme B (GZMB)/ interferon-gamma1 (IFNγ) transcription and directly acted upon glycogen synthase to skew metabolism towards greater glycolysis. We further showed that the inactivation of GSK-3α/β through siRNA or by SMIs substituted for CD28 co-stimulation in the potentiation of cytotoxic CD8+ CTL function. This data supports a model where GSK-3 mediates the dependency of anti-PD-1 immunotherapy on the expression of CD28. Overall, our data show that GSK-3 inactivation is an immune-sensitizer which assists the immune system to overcome tumor resistance to immune check-point blockade.

Citation Format: Christopher E. Rudd. Glycogen synthase kinase (GSK-3) inactivation downregulates PD-1 and synergizes with PD-1/PL1 and CTLA-4 blockade in cancer immunotherapy [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 1696.
Abstract 1698: Loss of MHC-I expression is associated with altered immune microenvironment and decreased response to PD-1 checkpoint inhibition
Authors: Gstalder Cecile , Pancholi Priya , Sadowicz Dorota , Haq Rizwan
Published: August 2018

Cancer immunotherapies, such as PD-1 inhibitors, achieve durable responses in a subset of cancer patients, however, a significant proportion of patients fail to respond to treatment. Defects in antigen presentation, such as the loss of MHC-I expression, are a major mechanism of resistance to PD-1 inhibitors. Developing new therapeutic strategies that overcome the lack of antigen presentation will improve cancer treatment and patient survival. To develop a pre-clinical model to evaluate therapies that could overcome resistance, we have generated a unique PD-1 blockade sensitive, syngeneic immunocompetent melanoma mouse model. We generated defects in antigen presentation using the CRISPR/Cas9 system, creating B2m-deficient melanoma cell lines. We demonstrated that B2m is necessary for IFN-gamma induced MHC-I surface expression. Unlike control tumors, we found that B2m-deficient tumors were resistant to PD-1 blockade, leading to decreased mouse overall survival. Using multi-parameter flow cytometry, we showed an increase in NK cell, regulatory T cell and dendritic cell infiltration in B2m-deficient tumors compared to controls, while the other immune cell population were unchanged. Since NK cell activity is negatively regulated by MHC-I, our findings suggest that additional factors are required to further invigorate infiltrating NK cells and to trigger a NK cell-mediated anti-tumor response. We are currently evaluating new approaches targeting NK cells and regulatory T cells on B2m-deficient tumors. This pre-clinical model could enable the development of a therapeutic strategy serving to improve the treatment of tumors lacking antigen presentation.

Citation Format: Cecile Gstalder, Priya Pancholi, Dorota Sadowicz, Rizwan Haq. Loss of MHC-I expression is associated with altered immune microenvironment and decreased response to PD-1 checkpoint inhibition [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 1698.
Abstract 170: Targeting colorectal cancer stem cells with the anticancer molecule thymoquinone
Authors: Ballout Farah R. , Fatfat Maamoun , Abdel-Samad Rana , Darwiche Nadine , Schneider-Stock Regine , Abou-Kheir Wassim , Muhtasib Hala-Gali
Published: August 2018

Introduction: 5-fluorouracil (5-Fu) remains the standard chemotherapy for metastatic colorectal cancer (CRC), but drug resistance and unpredictable cardiotoxicity limit its effectiveness. The high recurrence rates and the common resistance are thought to be due to a population of self-renewing cancer stem cells (CSCs). The black seed extract Thymoquinone (TQ) is a promising anticancer molecule known to inhibit cancer cell growth and progression in numerous cancer systems both in vitro and in vivo. This project aims to investigate the effect and mechanism of action of TQ on colon cancer stem/progenitor cells using two isogenic HCT116 colon cancer cell lines that differ in their 5-Fu drug sensitivity.

Methods: Sphere-formation and propagation assays were used to assess the efficacy of TQ on targeting self-renewal capacity of colon CSCs enriched from the sensitive and resistant cell lines in 3D cultures over several generations in comparison to 2D monolayers. In addition, xenotransplantation experiments were used to assess for the tumor initiation of 2D vs. 3D cells.

Results: Our results of TQ efficacy in 2D cell culture system showed that it reduced the viability of both cell lines. Importantly, our 3D results showed that TQ inhibits HCT116 colonosphere growth at 10-fold lower concentrations than those required to inhibit the growth of 2D monolayer cells. Interestingly, the injection of 100 spheres derived from HCT116 sensitive cell line and not the 2D equivalent cell density into NOD-SCID immunocompromised mice resulted in tumor development, suggesting that spheres are rich in cells with stem-like properties.

Conclusion: In summary, our data suggests that TQ might be an effective treatment strategy and may prevent colorectal cancer recurrence by targeting CSCs.

Citation Format: Farah R. Ballout, Maamoun Fatfat, Rana Abdel-Samad, Nadine Darwiche, Regine Schneider-Stock, Wassim Abou-Kheir, Hala-Gali Muhtasib. Targeting colorectal cancer stem cells with the anticancer molecule thymoquinone [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 170.
Abstract 1708: Nanofluidic drug-eluting seed for sustained intratumoral immunotherapy in triple negative breast cancer
Authors: Chua Corrine Ying Xuan , Jain Priya , Folci Marco , Ballerini Andrea , Rhudy Jessica , Gilbert April , Shaibala Shail , Bruno Giacomo , Filgueira Carly S. , Yee Cassian , Butler E. Brian , Grattoni Alessandro
Published: August 2018

Conventional systemic immunotherapy administration often results in insufficient anti-tumor immune response and adverse side effects. Delivering immunotherapeutics intratumorally could maximize tumor exposure, elicit robust anti-tumor immune response, and minimize toxicity. To fulfill the unmet clinical need for sustained local drug delivery and to avoid repeated intratumoral injections, we developed a nanofluidic-based device for intratumoral drug delivery called the nanofluidic drug-eluting seed (NDES). The NDES is inserted intratumorally using a minimally invasive trocar method similar to brachytherapy seed insertion and offers a clinical advantage of intratumoral drug elution. Drug diffusion from the NDES is regulated by physical and electrostatic nanoconfinement, thereby resulting in constant and sustained immunotherapeutic delivery without the need for repeated injections or clinician intervention. In this study, the NDES was utilized to deliver immunotherapeutics intratumorally in the 4T1 orthotopic murine mammary carcinoma model, which recapitulates triple negative breast cancer. We demonstrated that NDES-mediated intratumoral release of agonist immunotherapeutic monoclonal antibodies, OX40 and CD40, resulted in potentiation of local and systemic anti-tumor immune response and significant inhibition of tumor growth compared to control mice. Further, mice treated with NDES-CD40 demonstrated minimal liver damage compared to systemically treated mice. Collectively, our study highlights the NDES as an effective platform for sustained intratumoral immunotherapeutic delivery. The potential clinical impact is tremendous given that the NDES is applicable to a broad spectrum of drugs and solid tumors.

Citation Format: Corrine Ying Xuan Chua, Priya Jain, Marco Folci, Andrea Ballerini, Jessica Rhudy, April Gilbert, Shail Shaibala, Giacomo Bruno, Carly S. Filgueira, Cassian Yee, E. Brian Butler, Alessandro Grattoni. Nanofluidic drug-eluting seed for sustained intratumoral immunotherapy in triple negative 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 1708.
Abstract 1712: Assessing tumor mutation load using an NGS-based, routine-friendly target gene panel
Authors: Costa Jose , Reis Joana , Fernandes Margarida , Silva Rafaela , Cirnes Luis , Chaudhary Ruchi , Carneiro Fatima , Machado Jose C.
Published: August 2018

In several cancer models, it was shown that tumor mutation load correlates with response to immune checkpoint blockade therapy. However, whole exome sequencing of FFPE samples is not ideal for implementation on molecular pathology laboratories. In colorectal cancer (CRC), mutation load is correlated with microsatellite instability (MSI), which can therefore be used as surrogate marker for mutation load. In this study, we aimed at determining whether a target NGS-based mutation panel can be used for routine testing of mutation load in cancer, by assessing its performance in identifying MSI+ and MSI- CRC samples. The Oncomine Tumor Mutation Load Assay, which targets 409 genes corresponding to 1.7Mb of sequencing data, was used. It is a two-pool panel, optimized for FFPE samples, and only requires 20 ng of DNA in total. A cohort of 16 CRC samples was used. These included six cases MSI+, known to present a hypermutable phenotype caused by the loss of DNA mismatch repair activity, and 10 MSI- samples, which typically have a lower rate of somatic mutation. DNA was isolated from 10 uM slide cuts using the MagMAX FFPE DNA/RNA Ultra Kit. A multiplex of eight samples per 540 sequencing chip was sequenced using an Ion S5 XL system. In our data set, we observed an average of 67.2 mutations per Mb for the MSI+ samples and an average of 29.7 mutations per Mb for the MSI- samples (p=0.004). Using a cut-off of 40.0 mutations per Mb, we were able to classify correctly every sample as MSI+ or MSI-. Interestingly, we observed a tri-modal distribution of the samples, suggesting there might be a sub-group of MSI+ CRC cases that show a level of mutation load comparable to that of MSI- CRC cases. It remains to be seen whether these MSI+, low mutation load CRC cases are non-responders to treatment with immunotherapy. A validation cohort of CRC cases is currently being analyzed to validate our findings. In this study, we demonstrate it is viable to use a target and routine-amenable NGS-based sequencing gene panel to identify CRC samples with different levels of mutation load. It remains to be seen whether mutation load is a better predictor of response to immunotherapy than MSI status in CRC. This approach also needs to be validated in different tumor types.

Citation Format: Jose Costa, Joana Reis, Margarida Fernandes, Rafaela Silva, Luis Cirnes, Ruchi Chaudhary, Fatima Carneiro, Jose C. Machado. Assessing tumor mutation load using an NGS-based, routine-friendly target gene panel [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 1712.
Abstract 1745: Inhibition of chemokine receptor 2 (CCR2) with a small molecule antagonist enhances the effectiveness of checkpoint inhibition by altering the tumor microenvironment in mouse colorectal tumors: Reducing tumor size and increasing long term survival
Authors: Campbell James J. , Janson Christine , Ertl Linda , Li Chris , Miao Zhenhua , Krasinski Antoni , Lui Rebecca , Mali Venkat , McMahon Jeffrey , Zheng Yibin , Wang Yu , Zang Xiaoping , Chhina Vicky , Vilalta Marta , Kumamoto Alice , Dang Ton , Liu Shirley , Yao Simon , Zhang Penglie , Schall Thomas J. , Singh Rajinder
Published: August 2018

Mouse CT26 colorectal tumors are heavily infiltrated by tumor-specific CD8 T cells, but nevertheless grow rapidly in Balb/c mice. These tumors are partially responsive to anti-PD-1 (α-PD-1) monoclonal antibody therapy, which suggests that an active suppression of the tumor-specific cytotoxic T cells exists in the untreated tumor. As chemokine receptor 2 (CCR2) is expressed by a potentially suppressive leukocyte subset within these tumors (monocytic myeloid derived suppressor cells aka M-MDSCs), we aimed to test whether CCR2 blockade could enhance the anti-tumor effects of α-PD-1.

We have found that the therapeutic effects of α-PD-1 therapy are appreciably enhanced by specific blockade of CCR2 via a small molecule antagonist. This combined α-PD-1/CCR2i approach significantly decreases overall tumor size and increases the proportion of long-term survivors, with more than 50% of the mice (up to 73%) showing complete regression of a previously established tumor. The effects of this combined therapy are dependent on the presence of CD8+ T cells, as tumors do not respond to the therapy in CD8-depleted mice. The anti-CT26 tumor response is specific: long term survivors are resistant to re-inoculation with the CT26 tumor (even without further dosing of either drug) but are not resistant to the 4T1 breast tumor. CCR2 antagonism alters the tumor microenvironment by reducing the number of M-MDSC per gram of tumor (a CCR2hi population phenotypically defined as CD11b+/Ly6G-/Ly6Chi). Reduction in tumor size is inversely proportional to the ratio of CD8 T cells to M-MDSC.

These data are consistent with a hypothesis that CCR2 antagonism enhances α-PD-1 therapy by preventing M-MDSC from accumulating within the tumor, thus reducing their suppressive effects on cytotoxic T cells.

Citation Format: James J. Campbell, Christine Janson, Linda Ertl, Chris Li, Zhenhua Miao, Antoni Krasinski, Rebecca Lui, Venkat Mali, Jeffrey McMahon, Yibin Zheng, Yu Wang, Xiaoping Zang, Vicky Chhina, Marta Vilalta, Alice Kumamoto, Ton Dang, Shirley Liu, Simon Yao, Penglie Zhang, Thomas J. Schall, Rajinder Singh. Inhibition of chemokine receptor 2 (CCR2) with a small molecule antagonist enhances the effectiveness of checkpoint inhibition by altering the tumor microenvironment in mouse colorectal tumors: Reducing tumor size and increasing long term survival [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 1745.
Abstract 1797: Characterization of a novel androgen receptor coregulator RIPK1
Authors: Hsu Cheng-Lung , Liu Jai-Shin , Lin Ting-Wei , Lin Chun-Cheng , Wu Wen-Guey
Published: August 2018

Using bicalutamide-androgen receptor (AR) DNA binding domain-ligand binding domain as bait, we observed enrichment of FxxFY motif-containing peptides. Protein database searches revealed the presence of receptor-interacting protein kinase 1 (RIPK1) harboring one FxxFY motif. RIPK1 interacted directly with AR and suppressed AR transactivation in a dose-dependent manner. Domain mapping experiments showed that the FxxFY motif in RIPK1 is critical for interactions with AR and the death domain of RIPK1 plays a crucial role in its inhibitory effect on transactivation. In terms of tissue expression, RIPK1 levels were markedly higher in benign prostate hyperplasia and non-cancerous tissue regions relative to the tumor area. With the aid of computer modeling for screening of chemicals targeting activation function 2 (AF-2) of AR, we identified oxadiazole derivatives as good candidates and subsequently generated a small library of these compounds. A number of candidates could effectively suppress AR transactivation and AR-related functions in vitro and in vivo with tolerable toxicity via inhibiting AR-peptide, AR-coregulator and AR N-C interactions. Combination of these chemicals with antiandrogen had an additive suppressive effect on AR transcriptional activity. Our collective findings may pave the way in creating new strategies for the development and design of anti-AR drugs.

Citation Format: Cheng-Lung Hsu, Jai-Shin Liu, Ting-Wei Lin, Chun-Cheng Lin, Wen-Guey Wu. Characterization of a novel androgen receptor coregulator RIPK1 [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 1797.
Abstract 1799: ATRX, DAXX or MEN1 mutant pancreatic neuroendocrine tumors are a distinct “alpha-cell signature” subgroup
Authors: Laddha Saurabh V. , Chan Chang S. , Lewis Peter , Koletsky Matthew , Robzyk Kenneth , Silva Edaise Da , Torres Paula J. , Untch Brian , Bose Promita , Chan Timothy , Klimstra David S. , Allis David C. , Tang Laura H.
Published: August 2018

Pancreatic neuroendocrine tumors (PanNETs) or islet cell tumors are a rare neuroendocrine malignancy with an annual incidence of less than 1 per 100,000 per year. Current classification scheme for PanNETs include grade and stage. While well-differentiated PanNETs can be successfully treated with surgery, there are few treatments for metastatic PanNETs. A greater understanding of the cells of origin of PanNETs, tumor progression and pathway pathogenesis may guide the development of novel therapeutic options. The most commonly mutated genes in PanNETs are ATRX, DAXX, and MEN1. Little is known about the cells-of-origin for non-functional neuroendocrine tumors. Here, we genotyped 64 PanNETs for mutations in ATRX, DAXX, and MEN1 and found 37 tumors (58%) carry mutations in these three genes (A-D-M mutant PanNETs) and this correlates with a worse clinical outcome than tumors carrying the wild-type alleles of all three genes (A-D-M WT PanNETs). We performed RNA sequencing (n=33) and Illumina 450K DNA methylation (n=32) analysis on randomly selected PanNETs to reveal two distinct subgroups with one group consisting exclusively of A-D-M mutant PanNETs. Pair-wise correlation of gene expression between all PanNETs, showed A-D-M mutant PanNETs are more homogeneous as a group than A-D-M WT PanNETs. Among A-D-M mutant PanNETs, mutants with the same genotype (mutations in ATRX/DAXX/MEN1) did not show greater gene expression correlation. Two biomarkers differentiating A-D-M mutant from A-D-M WT PanNETs were high ARX gene expression and low PDX1 gene expression with PDX1 promoter hyper-methylation in the A-D-M mutant PanNETs. Moreover, A-D-M mutant PanNETs had a gene expression signature similar to that of alpha cells (pval < 0.009) of pancreatic islets including increased expression of HNF1A and its transcriptional target genes. We validated our subtype classification and A-D-M mutant panNET alpha signature using two independent PanNETs expression dataset. This gene expression profile suggests that A-D-M mutant PanNETs originate from or transdifferentiate into a distinct cell type similar to alpha cells.

Citation Format: Saurabh V. Laddha, Chang S. Chan, Peter Lewis, Matthew Koletsky, Kenneth Robzyk, Edaise Da Silva, Paula J. Torres, Brian Untch, Promita Bose, Timothy Chan, David S. Klimstra, David C. Allis, Laura H. Tang. ATRX, DAXX or MEN1 mutant pancreatic neuroendocrine tumors are a distinct “alpha-cell signature” subgroup [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 1799.
Abstract 1805: Development of a selective androgen receptor degrader (SARD) for treatment of castration-resistant prostate cancer
Authors: Yao ZhongKe , Wardell Suzanne , Spasojevic Ivan , Norris John , Katzenellenbogen John , McDonnell Donald , Josan Jatinder S.
Published: August 2018

Current treatments for prostate cancer are centered on blocking androgen-signaling axis, which is the target of several clinical androgen receptor (AR) antagonists such as enzalutamide. Recent studies have shown that a single AR mutation (F876L) converts enzalutamide from an antagonist to an agonist—a fate shared by earlier antagonists as well such as bicalutamide and flutamide. While hormonal therapy is often successful in the initial stages of the disease, prostatic tumors inevitably become resistant to these therapeutics. Remarkably though, several mechanistic studies suggest that the androgen receptor signaling remains active even in these hormonal refractory cancers, which suggests that AR remains a viable target in the castration-resistant prostate cancers (CRPC). Thus, novel therapeutics that target and degrade AR could provide unique druggable opportunities for complete and more sustained AR inhibition in prostate cancers. Based on an AR-gelsolin interaction in a mammalian two-hybrid luciferase assay, we conducted a screen of an in-house library of 170,000 compounds, re-assayed and validated the top 2K hits. The top 500 hits were then characterized in a battery of assays such as AR-driven gene expression, inhibition of cell proliferation in WT and mutant cell lines, ChIP-seq, transcriptional and conformational profiling, and AR degradation studies. We have identified a selective androgen receptor degrader (SARD) series that shows efficacy against both WT and AR mutants. Further structure-activity relationship (SAR) studies revealed analogs with IC50 equivalent or superior to enzalutamide. In vivo studies are currently under way to evaluate the efficacy of the optimized lead in mouse tumor xenografts. These preclinical findings highlight the utility of SARDs as an effective therapeutic prostate tumor strategy in the context of AR mutations and overexpression that bestow resistance to the second-generation AR antagonists.

Citation Format: ZhongKe Yao, Suzanne Wardell, Ivan Spasojevic, John Norris, John Katzenellenbogen, Donald McDonnell, Jatinder S. Josan. Development of a selective androgen receptor degrader (SARD) for treatment of castration-resistant prostate 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 1805.
Abstract 1809: Expression of genes in the nuclear receptor superfamily defines a set of prognostic biomarkers in endometrial cancer
Authors: Hoivik Erling A. , Tangen Ingvild L. , Mauland Karen M. , Halle Mari K. , Werner Henrica J. , Trovik Jone , Krakstad Camilla
Published: August 2018

The nuclear receptor (NR) superfamily in humans consists of 48 transcription factors that form a network to sense lipophilic molecules from the diet, metabolism and hormone production, which ultimately regulate development, circadian rhythm, metabolism, proliferation and differentiation in the normal state. In cancer, biomarker signatures that provide either prognostic or predictive information are useful when suggesting therapeutic strategies. However, when performing differential gene expression analysis on global datasets, there is little overlap among the gene sets identified, even among similar datasets of same cancers. The fourth-eight NRs in cancers could represent a unique predefined pan-cancer subset of potential biomarkers in gynecologic cancers. Of note, NRs, in particular, estrogen, progesterone and androgen receptors (ESR1, PGR, AR), are strongly involved in the progression of gynecologic cancers, as revealed by us and others exemplified by endometrial cancer. Further, NRs are appealing targets, as they are regulated by ligand-receptor interactions, and approximately 15% of all pharmacologic drugs target factors within this group. We investigate the association of NR expressions and clinical outcome, and reveal NR signatures that may provide useful information as a biomarker in gynecologic cancers, with emphasis on endometrial cancer.

Citation Format: Erling A. Hoivik, Ingvild L. Tangen, Karen M. Mauland, Mari K. Halle, Henrica J. Werner, Jone Trovik, Camilla Krakstad. Expression of genes in the nuclear receptor superfamily defines a set of prognostic biomarkers in endometrial 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 1809.