bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 99: Remodeling of calcium influx pathways in models of cancer associated fibroblasts in breast cancer
Authors: Monteith Greg , Sadras Francisco , Stewart Teneale , Robitaille Melanie , Croft Priyakshi Kalita-de , Soon Patsy , Saunus Jodi , Lakhani Sunil , Roberts-Thomson Sarah
Published: August 2019

Calcium (Ca2+) influx pathways are remodelled in a variety of disease states, and alterations in the expression of specific Ca2+ permeable ion channels are a feature of some breast cancer subtypes. However, no studies have yet assessed possible alterations in Ca2+ influx pathways in the context of cancer-associated fibroblasts (CAFs), which are important in the tumor microenvironment and disease progression. The aim of this study was to identify possible changes in the nature of Ca2+ influx in CAFs and to define the role of Ca2+ signaling in the induction of breast CAFs. Levels of mRNA for voltage-gated and store-operated Ca2+ entry (SOCE) components were assessed in paired normal and CAF patient samples using qRT-PCR. The immortalised human mammary fibroblast cell line HMF3S, was treated with transforming growth factor beta (TGFβ) to induce a CAF phenotype (HMF3S-CAF) as confirmed by the expression of alpha smooth muscle actin (αSMA). HMF3S-CAF and HMF3S were also compared for expression of Ca2+ channels using qRT-PCR and functional store operated Ca2+ entry (SOCE) using a Fluorescence Imaging Plate Reader (FLIPR) Ca2+ assay. Specific Ca2+ channel subtypes were pharmacologically inhibited during TGFβ treatment to assess their role in CAF induction. Ca2+channel levels were altered in CAF patient samples compared to their paired controls and also in TGFβ-treated HMF3S cells. Voltage-gated Ca2+channel inhibitors significantly decreased TGFβ-mediated CAF activation. These data suggest that Ca2+ signaling is remodeled in CAFs and that the Ca2+ signal is important in breast CAF induction.

Citation Format: Greg Monteith, Francisco Sadras, Teneale Stewart, Melanie Robitaille, Priyakshi Kalita-de Croft, Patsy Soon, Jodi Saunus, Sunil Lakhani, Sarah Roberts-Thomson. Remodeling of calcium influx pathways in models of cancer associated fibroblasts in breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 99.
Abstract 993: Chemotherapy enhances exosome secretion via upregulation of cholesterol metabolism in acute myeloid leukemia
Authors: Hong Chang-Sook , Jeong Emily J. , Razzo Beatrice , Boyiadzis Michael , Whiteside Theresa L.
Published: August 2019

Therapies for Acute Myelogenous Leukemia (AML) have not been successful largely due to disease recurrence after chemotherapy. Recent studies showed that exosomes play a significant role in leukemia chemo-resistance. Levels of exosomes in patients’ plasma are elevated at AML diagnosis relative to those in normal donors’ plasma and remain elevated when patients reach complete remission (CR). These exosomes carry immunosuppressive molecules, interfere with anti-leukemia immunity and promote blast chemoresistance. We hypothesized that the development of methods for blocking exosome secretion could benefit AML patients. To understand the mechanisms of enhanced exosome secretion in AML blasts, we focused on cholesterol synthesis in blasts and its relationship to exosome secretion. Cholesterol metabolism in AML cell lines after treatment of chemotherapeutic agents (cytarabine and decitabine) was shown to enhance (p<0.005) intracellular level of cholesterol and the expression of HMGCR (3-hydroxy-3-methyl-glutaryl-coenzyme A reductase), the rate-limiting enzyme in cholesterol synthesizing mevalonate pathway. Consequently, the production of exosomes in the cell culture supernatants increased (p<0.02). Treatment with an HMGCR inhibitor, simvastatin, or siRNAs targeting HMGCR blocked (p<0.02) the chemotherapy- induced enhancement of exosome production. Exosomes carry HMGCR and chemotherapy enhanced HMGCR levels on exosomes. Our results show that chemotherapy enhances exosome secretion by increasing cholesterol synthesis in leukemic blasts. A pharmacologic blockade of HMGCR with simvastatin emerges as a potential future therapeutic for exosomes in AML.

Note: This abstract was not presented at the meeting.

Citation Format: Chang-Sook Hong, Emily J. Jeong, Beatrice Razzo, Michael Boyiadzis, Theresa L. Whiteside. Chemotherapy enhances exosome secretion via upregulation of cholesterol metabolism in acute myeloid leukemia [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 993.
Abstract 995: A new thiadiazine derivative induces oxidative stress dependent JNK pathway activation and cell death in hepatocellular carcinoma
Authors: Kahraman Deniz C. , Guven Ebru B. , Tozkoparan Birsen , Atalay Rengul C.
Published: August 2019

Hepatocellular carcinoma (HCC) is the fifth most common and the second lethal cancer worldwide. HCC is resistant to conventional chemotherapy and radiotherapy due to its highly heterogenous structure. Therefore, it is crucial to design and develop novel therapeutic strategies against HCC. Non-steroidal anti-inflammatory drugs (NSAIDs) have long been studied for the treatment of acute and chronic conditions with pain and inflammation. In recent years, evidence from various studies suggested that NSAIDs reduce the incidence and mortality of various types of cancers. Here, investigated the possible cytotoxic bioactivities of a series of triazolothiadiazine derivatives on HCC cells, which have been previously reported as potent analgesic/anti-inflammatory compounds. For this purpose, we first investigated the anticancer effect of our compounds bearing a triazolothiadiazine core. Initially, 30 compounds were tested against cancer cells. Among all the compounds, three of them (7a, 7b and 7c) showed noticeable cytotoxic activities within µM concentrations and were selected to be screened against a panel of HCC cell lines. Compound 7b was identified as a promising anti-cancer agent against liver cancer cells with cytotoxic doses (less than 5µM) assessed by both the SRB assay and RT-CES analysis and was analyzed with further in vitro and in vivo experiments to disclose the underlying mechanism of its action in HCC cells. Time- and dose- dependent growth inhibition upon treatment with compound 7b was observed due to cell cycle arrest at the G2/M phase and apoptosis. After detecting the activation of SAPK/JNK pathway, it was shown that ROS accumulation was triggering the downstream events and eventually apoptotic cell death. Furthermore, upon treatment with compound 7b, overall survival of xenografts increased, while the tumor size decreased compared to control groups. Additionally, we investigated the potential of this compound on liver cancer stem cell population (CD133+/EpCAM+) which are known to be responsible for drug resistance in HCC. Compound 7b was bioactive against LCSCs and decreased the ratio of CD133+/EpCAM+ population significantly in both Huh7 and Mahlavu cells. Altogether, the anti-tumor and anti-resistance effects of compound 7b approves that this small molecule can be considered as an anti-cancer agent for liver cancer therapeutics.

Citation Format: Deniz C. Kahraman, Ebru B. Guven, Birsen Tozkoparan, Rengul C. Atalay. A new thiadiazine derivative induces oxidative stress dependent JNK pathway activation and cell death in hepatocellular carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 995.
Abstract CT176: Phase III PANOVA study of tumor treating fields (150 kHz) in combination with nab-paclitaxel and gemcitabine for front-line treatment of locally-advanced pancreatic adenocarcinoma (LAPC)
Authors: Weinberg Uri , Farber Ori , Giladi Moshe , Bomzon Zeev , Kirson Eilon
Published: August 2019

Background: Tumor Treating Fields (TTFields) are a non-invasive, regional antimitotic treatment modality, which has been approved for the treatment of patients with glioblastoma by the FDA. TTFields predominantly act by disrupting the formation of the mitotic spindle during metaphase. TTFields were effective in multiple preclinical models of pancreatic cancer. The Phase II PANOVA study [NCT01971281] of TTFields in pancreatic cancer (metastatic and LAPC) combined with nab-paclitaxel and gemcitabine, demonstrated no TTFields-related serious adverse events; key TTFields-related AEs was manageable skin toxicity. TTFields plus gemcitabine and nab-paclitaxel showed median PFS was 12.7 months. The Phase III PANOVA-3 trial [NCT03377491] is designed to test the efficacy of adding TTFields to nab-paclitaxel and gemcitabine combination in LAPC.

Methods: Patients (N = 556) with unresectable, LAPC (per NCCN guidelines) will be enrolled in this prospective, randomized trial. Patients should have an ECOG score of 0-2 and no prior progression or treatment. Patients will be stratified based on their performance status and geographical region, and will be randomized 1:1 to TTFields plus nab-paclitaxel and gemcitabine or to nab-paclitaxel and gemcitabine alone. Chemotherapy will be administered at standard dose of nab-paclitaxel (125 mg/m2) and gemcitabine (1000 mg/m2 once weekly). TTFields (150kHz) will be delivered at least 18 hours/day until local disease progression per RECIST Criteria V1.1. Follow up will be performed q8w, including a CT scan of the chest and abdomen. Following local disease progression, patients will be followed monthly for survival. Overall survival will be the primary endpoint and progression-free survival, objective response rate, rate of resectability, quality of life and toxicity will all be secondary endpoints. Sample size was calculated using a log-rank test comparing time to event in patients treated with TTFields plus chemotherapy with control patients on chemotherapy alone. The PANOVA-3 study is designed to detect a hazard ratio 0.75 in overall survival. Type I error is set to 0.05 (two-sided) and power to 80%.

Citation Format: Uri Weinberg, Ori Farber, Moshe Giladi, Zeev Bomzon, Eilon Kirson. Phase III PANOVA study of tumor treating fields (150 kHz) in combination with nab-paclitaxel and gemcitabine for front-line treatment of locally-advanced pancreatic adenocarcinoma (LAPC) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr CT176.
Abstract CT218: SYNERGY-AI: Artificial intelligence based precision oncology clinical trial matching and registry
Authors: Kurnaz Selin , Loaiza-Bonilla Arturo
Published: August 2019

Background: Precision oncology encompasses the implementation of high level of evidence disease-specific and biomarker-driven diagnostic and treatment recommendations for optimized cancer care. Artificial Intelligence (AI), telemedicine and value-based care may optimize clinical trial enrollment (CTE) and overall cost-benefit. This ongoing, international registry for cancer pts evaluates the feasibility and clinical utility of an AI-based precision oncology clinical trial matching tool, powered by a virtual tumor boards (VTB) program, and its clinical impact on pts with advanced cancer to facilitate CTE, as well as the financial impact, and potential outcomes of the intervention.

Methods: The SYNERGY-AI Registry is an international prospective, observational cohort study of eligible adult and pediatric pts with advanced solid and hematological malignancies, for whom the decision to consider CTE has already been made by their primary providers (PP). Using a proprietary application programming interface (API) linked to existing electronic health records (EHR) platforms, individual clinical data is extracted, analyzed and matched to a parametric database of existing institutional and non-institutional CTs. Machine learning algorithms allow for dynamic matching based on CT allocation and availability for optimized matching. Patients voluntarily enroll into registry, which is non-interventional with no protocol-mandated tests/procedures—all treatment decisions are made at the discretion of PP in consultation with their pts, based on the AI CT matching report, and VTB support. CTE will be assessed on variables including biomarkers, barriers to enrollment. Study duration anticipated as ~36 mo (~24-mo enrollment followed by 12 mo of data collection, to occur every 3 mo). The primary analysis will be performed 12 mo after last pt enrolled. The impact time to initiation of CTE on PFS and OS will be estimated by Kaplan-Meier and Cox multivariable survival analysis. Enrollment is ongoing, with a target of ≥ 1500 patients. Key inclusion criteria: Pts with solid and hematological malignancies; cancer-related biomarkers. Key exclusion criteria: ECOG PS > 2; abnormal organ function; hospice enrollment.

ClinicalTrials.gov Identifier: NCT03452774

https://clinicaltrials.gov/ct2/show/NCT03452774

Citation Format: Selin Kurnaz, Arturo Loaiza-Bonilla. SYNERGY-AI: Artificial intelligence based precision oncology clinical trial matching and registry [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr CT218.
Abstract LB-003: Intracellular delivery of SOCS3 suppresses solid tumor progression
Authors: Shin Seulmee
Published: August 2019

Introduction Suppressor of cytokine signaling 3 (SOCS3) functions as a negative-feedback regulator of JAK/STAT signaling that suppresses JAK kinase activity and promotes degradation of the activated cytokine receptor complex. Loss of SOCS3 enhances the growth and survival of some solid tumors; therefore, methods to replenish intracellular levels of the protein may provide an effective therapy against solid tumors dependent on JAK/STAT signaling for growth or survival.

Objective The present study utilized advanced macromolecule transduction domain (aMTD) sequences to develop improved cell-permeable (iCP-) SOCS3 as a protein-based biotherapeutic against solid tumors including gastric-, colorectal, lung-, breast-cancer and glioblastoma.

Methods Cell-permeable SOCS3 proteins, with (iCP-SOCS3) and without (Non-CP-SOCS3) a 12-amino acid aMTD sequence or containing an earlier generation of MTD based on the signal peptide of FGF4, termed membrane-translocating motif (MTM) were expressed and purified from E. coli. The proteins also contained a solubilization domain (SD) to enhance the solubility of the recombinant proteins in physiological buffers. The therapeutic potential of iCP-SOCS3 as anti-cancer agent for solid tumors was examined both in cultured cells and in human-mouse xenograft models.

Results Compared to CP-SOCS3, iCP-SOCS3 fused to aMTD exhibited higher solubility and yield (25- and 300-folds higher, respectively) that are qualified to be developed for clinical use. Moreover, it exhibited cell-/tissue-permeability along with strong biological activity that was shown by significantly suppressed IFN-γ-induced phosphorylation of STAT1 and STAT3. In vitro study conducted with various cancer cell lines demonstrated that iCP-SOCS3 significantly suppresses cancer-associated phenotypes (e.g., >80% inhibition of proliferation in lung cancer and glioblastoma, >70% induction of apoptosis in gastric cancer, >65% inhibition of migration/invasion in gastric cancer) and induces changes in biomarker expression (e.g., p21, cleavage caspase-3 in breast cancer). In addition, iCP-SOCS3 significantly suppressed the tumor growth of human solid tumor xenografts (65% inhibition in gastric-, 79% in colorectal-, 69% in lung-, 63% in breast-cancer and 78% in glioblastoma CDXs, respectively).

Conclusion In conclusion, these results provide further evidence that SOCS3 can function as a tumor suppressor and intracellular delivery of SOCS3 with iCP-SOCS3 may provide novel protein therapy against solid tumors.

Citation Format: Seulmee Shin. Intracellular delivery of SOCS3 suppresses solid tumor progression [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr LB-003.
Abstract LB-012: US cancer centers of excellence coordination of operational strategies contribute to enhanced accrual of racial and ethnic minorities in clinical trials
Authors: Regnante Jeanne M. , Richie Nicole A. , Fashoyin-Aje Lola , Hall Laura Lee , Highsmith Quita , Louis J'Aimee A. , Turner Kenneth , Hoover Spencer C. , Lee Simon Craddock , Williams Erin L. , Adams Homer , Obasaju Coleman , Sargeant Ify , Geday Madeline , Gandee Marianne , Watson Rayneisha , Chen Moon S.
Published: August 2019

Background: Racial and ethnic minority groups (REMGs) have low rates of inclusion in cancer trials. With the rise of precision medicine, it is critical that study populations in clinical research reflect the changing US demographics.

Methods: Criteria were developed to identify cancer centers able to accrue a higher than average proportion of REMGs into clinical trials. Comprehensive interviews were conducted with leaders of identified cancer centers to ascertain operational strategies contributing to enhanced accrual of REMGs.

Results: Eight representative centers reported a REMG accrual rate range in cancer research between 10-50% in a 12-month reporting period and met other criteria for inclusion, and 14 leaders participated in this assessment. Key findings were that centers: had a metric collection and reporting approach; routinely captured race and ethnicity data within databases accessible to research staff; had operational standards to support access and inclusion; developed practices to facilitate sustained patient participation during clinical trials; had strategies to decrease recruitment time and optimize clinical study design; and identified low-resource strategies for improving accrual. There was also a commitment to establish processes that support the patient’s provider as the key influencer of patient recruitment into clinical trials.

Conclusion: Conduct of cancer research requires coordination of an operational framework governed by metrics in order to achieve high accrual of diverse populations in clinical trials. Leading US cancer centers have established key Operational Excellence practices and other notable practices which are critical for optimizing sustained inclusion of diverse populations in cancer clinical research.

Citation Format: Jeanne M. Regnante, Nicole A. Richie, Lola Fashoyin-Aje, Laura Lee Hall, Quita Highsmith, J'Aimee A. Louis, Kenneth Turner, Spencer C. Hoover, Simon Craddock Lee, Erin L. Williams, Homer Adams, Coleman Obasaju, Ify Sargeant, Madeline Geday, Marianne Gandee, Rayneisha Watson, Moon S. Chen. US cancer centers of excellence coordination of operational strategies contribute to enhanced accrual of racial and ethnic minorities in clinical trials [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr LB-012.
Abstract LB-048: WRN helicase is a synthetic lethal target in microsatellite unstable cancers
Authors: Chan Edmond M. , Shibue Tsukasa , McFarland James , Gaeta Benjamin , Vazquez Francisca , Bass Adam J.
Published: August 2019

Microsatellite instability (MSI), a class of genetic hypermutability that arises from impaired DNA mismatch repair (MMR), contributes to the development of many malignancies including colon, endometrial, gastric, and ovarian cancers. While immune checkpoint blockade (ICB) has been an effective therapy for many patients with MSI cancers, numerous patients with MSI malignancies do not respond to ICB or the use of these agents are limited by their toxicity. Hence, there is still a pressing need to develop further therapies against MSI cancers. One approach to develop novel therapeutics is to leverage synthetic lethality, a phenomenon whereby the simultaneous occurrence of two or more genetic events lead to cell death but one event alone does not. DNA repair processes represent attractive synthetic lethal targets since many cancers exhibit an impaired DNA repair pathway, which can lead these cancers to become dependent on specific repair proteins. The success of poly (ADP ribose) polymerase (PARP) inhibitors in homologous recombination-deficient cancers highlights the potential of this approach. Hypothesizing that other DNA repair defects would give rise to alternative synthetic lethal relationships, we asked if there are specific dependencies in MSI cancers. Here, we analyzed data from large-scale CRISPR/Cas9 and RNA interference (RNAi) functional genomic screens and found that the RecQ DNA helicase WRN was selectively essential in MSI models in vitro and in vivo, but dispensable in microsatellite stable models. WRN silencing induced double-strand DNA breaks, activated a DNA-damage response, and promoted apoptosis and cell cycle arrest preferentially in MSI models. MSI cancer models specifically required WRN’s helicase activity, but not its exonuclease activity. These findings expose WRN as a synthetic lethal vulnerability and promising drug target for MSI cancers.

Citation Format: Edmond M. Chan, Tsukasa Shibue, James McFarland, Benjamin Gaeta, Francisca Vazquez, Adam J. Bass. WRN helicase is a synthetic lethal target in microsatellite unstable cancers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr LB-048.
Abstract LB-060: Characterization of the immune checkpoint inhibitor response in the MC38 murine colon cancer model
Authors: Fadden Patrick , Bui Thi , Hurtado David , Davis Kelli , Belle Ian , Krontz Kathrine , Hauser Jacob , Li Na , Takayama Kyle , Sokolowski Cristina , Wood Edgar
Published: August 2019

Immune focused interventions remain a high priority for many drug discovery efforts, spurred on by the success of immune checkpoint therapies such as anti-PD-1, anti-PD-L1, and anti-CTLA-4 inhibitory antibodies. Preclinical efficacy assessments of novel immune-oncology therapies requires a functional immune system which limits the usefulness of traditional xenograft models and drive the use of humanized (human immune cell engrafted animals) and syngeneic model systems. Syngeneic mouse tumors are popular model systems in which to evaluate these novel therapies due the presence of fully intact mouse immune system and ease of accessibility. The MC38 mouse colon cancer model is popular for efficacy assessment studies due to its responsiveness to typical immune checkpoint inhibitors. We endeavored to characterize the immune response to checkpoint inhibitors in MC38 tumors using flow cytometry, gene expression analysis, and immunohistochemistry (IHC). Gene expression analysis provided a signature of gene changes that correlate to immune driven changes in tumor growth and may be used in preclinical pharmacodynamics studies as evidence of mode of action for other novel immune-oncology therapies. In addition, gene overrepresentation analysis highlighted the presence and involvement of B cell populations in the MC38 tumor environment which was supported by IHC data that show distinctive B cell staining in what resemble tumor associated tertiary lymph structures. These finding suggests that MC38 may provide a good model system for evaluating therapies that can modulate or impact tumor infiltrating B cell populations.

Citation Format: Patrick Fadden, Thi Bui, David Hurtado, Kelli Davis, Ian Belle, Kathrine Krontz, Jacob Hauser, Na Li, Kyle Takayama, Cristina Sokolowski, Edgar Wood. Characterization of the immune checkpoint inhibitor response in the MC38 murine colon cancer model [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr LB-060.
Abstract LB-066: BiTE-armored CARs overcome antigen escape in EGFRvIII-targeted therapy for glioblastoma
Authors: Choi Bryan D. , Yu Xiaoling , Castano Ana P. , Bouffard Amanda A. , Curry William T. , Carter Bob S. , Maus Marcela V.
Published: August 2019

Glioblastoma (GBM) is a devastating disease with an extremely poor prognosis. Immune therapy with T cells engineered to express chimeric antigen receptors (CARs), represents a promising alternative to conventional therapy, but responses have been limited to date due to heterogeneous target antigen expression and the emergence of immune escape following treatment with CAR T cells directed at a single target. This was observed in clinical studies with CART-EGFRvIII, wherein EGFRvIII-targeted T cells successfully localized to the brain tumor microenvironment, but ultimately failed to prevent disease progression—with post-treatment specimens demonstrating high levels of wild-type EGFR despite reduced expression of EGFRvIII. To help address this therapeutic barrier, we developed a novel CAR construct engineered for local delivery of bispecific T-cell engagers (BiTEs) that target residual tumor. Specifically, EGFRvIII-targeted CAR T cells were engineered to secrete BiTEs against wild-type EGFR, which is not expressed in normal brain but frequently amplified in GBM, recurrent disease and other cancers. Our results demonstrate that human T cells are efficiently transduced with the dual CART.BiTE transgene, and that modified cells successfully secrete biologically active EGFR-specific BiTEs that not only redirect CAR T cells but also recruit and activate untransduced bystander T cells against wild-type EGFR. Recapitulating clinical data, EGFRvIII CAR T cells were unable to completely treat tumors with heterogenous EGFRvIII expression, leading to outgrowth of EGFRvIII-negative, EGFR-positive recurrence. Conversely, CART.BiTE cells mediated potent antitumor efficacy in the setting of heterogeneous tumors and EGFRvIII antigen loss. In these models, infusion of CART.BiTE cells yielded extended survival and cured mice with even late-stage, established intracerebral tumors, including those derived from glioma cell lines and patient-derived glioma neurosphere cultures. Unlike CAR T cells directly targeting EGFR, which caused on-target toxicity against human skin grafts in vivo, secreted BiTE-EGFR was locally effective at exceedingly low concentrations that did not mediate immune responses against healthy human tissue. These results demonstrate that CARs and BiTEs can be combined strategically to mitigate the impact of antigen heterogeneity in GBM, and also provide a unique T-cell-based delivery method for BiTEs to tumors in the brain.

Citation Format: Bryan D. Choi, Xiaoling Yu, Ana P. Castano, Amanda A. Bouffard, William T. Curry, Bob S. Carter, Marcela V. Maus. BiTE-armored CARs overcome antigen escape in EGFRvIII-targeted therapy for glioblastoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr LB-066.
Abstract LB-076: Personal neoantigen immunotherapy in hepatocellular carcinoma
Authors: Peng Sui , Peng Zhenwei , Xu Lixia , Mei Jie , Tang Longqing , Han Yanyan , Kuang Ming
Published: August 2019

Hepatocellular carcinoma (HCC) is one of the most common cancers and the leading causes of mortality in China with limited therapeutic options. To investigate whether neoantigens could induce tumor specific immune responses in patients with HCC, neoantigen stimulating cellular therapy (neo-MASCT) was applied after radical resection. Neo-MASCT was a cell-based immunotherapy with injections of mature dendritic cells (DCs) loaded with a peptide pool of multiple shared tumor associated antigens (TAAs) and several personalized neoantigens followed by autologous T cells stimulated by these DCs. To obtain neoantigens, fresh tumor samples were acquired immediately after biopsy or surgery for subsequently WES and RNAseq. All mutations including SNV, non-frame shift insert/deletion (Indel), and neoORF were detected by comparing NGS data from tumors to normal tissues. All neo-epitope candidates were predicted by our own proprietary algorithm MASNEO according to the patient’s HLA class I genotypes. Long neoantigen peptides containing 25-31 amino acids with higher affinities were selected for further synthesis and treatment. Peptides containing multiple neo-epitopes were preferred. Until now, eight patients had received neo-MASCT, and seven of them were tested for specific immune responses against both TAAs and neoantigens using IFNγ Elispot assay. The results showed that Neo-MASCT induced TAA-specific immune responses in five patients (5/7, 71%), and induced neoantigen-specific immune responses in six patients (6/7, 86%), respectively. One patient demonstrated specific T cell responses against all the five neoantigen peptides (5/5, 100%) after neo-MASCT treatment. The average responsive rate of neoantigens was 65% (22/34 peptides) in the six responding patients. In conclusion, our results demonstrate that neo-MASCT is well-tolerated in HCC patients and elicits immune responses against multiple tumor antigens, especially personalized neoantigens. We will continuously monitor the immune responses against neoantigens, and use the results to train and optimize our predicting algorithm. We will also evaluate the clinical benefit of neo-MASCT in further clinical trials with more patients.

Citation Format: Sui Peng, Zhenwei Peng, Lixia Xu, Jie Mei, Longqing Tang, Yanyan Han, Ming Kuang. Personal neoantigen immunotherapy in hepatocellular carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr LB-076.
Abstract LB-084: Human T-cell lymphoma invasion and metastasis 2 promotes chronic inflammation mediated tumorigenicity
Authors: Chan Ya-Lin , Lai Wei-Chung , Tsai Shaw-Jenq , Sun H. Sunny
Published: August 2019

Cancer development is a very complex, multi-step process with mechanisms largely unknown. Despites numerous efforts in identifying many oncogenes and tumor suppressor genes that contribute to the development of cancers, the etiology of cancer remains poorly understood. Our previous studies showed the ectopic expression of human T-Cell Lymphoma Invasion and Metastasis 2, variant b (TIAM2S) in liver cells promotes liver cancer tumorigenesis. Nevertheless, the mechanism that underlies its oncogenic effect remains unclear. This study aims to investigate the role of TIAM2S in spontaneous and carcinogen-induced tumorigenesis. We established TIAM2-overexpressing transgenic (TG) mouse lines and characterize the genotypes and phenotypes of these transgenic mice in great details. In addition, we apply azoxymethane (AOM)-induced colon cancer model to examine the tumor susceptibility in these TG mice. We found that TIAM2S expressed murine model developed chronic inflammation and resulted in high incidence of lymphocytic infiltration in various organs. Furthermore, AOM-induced colon tumor developing in younger age of TG mice compared to the WT. Through the examination of immune cells and cytokine/chemokine profiles, we found that serotonin-mediated chronic inflammation, especially IL-23+/IL-17+/CD8+ T lymphocytes were characterized in the tertiary lymphoid organs in the TG mic. Altogether, this study demonstrate that TIAM2S mediates chronic inflammation and increases the susceptibility of colon cells to environmental hit and lead to the development of colon cancer.

Citation Format: Ya-Lin Chan, Wei-Chung Lai, Shaw-Jenq Tsai, H. Sunny Sun. Human T-cell lymphoma invasion and metastasis 2 promotes chronic inflammation mediated tumorigenicity [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr LB-084.
Abstract LB-089: Direct BAX activation effectively induces apoptosis in anaplastic thyroid cancer cells
Authors: Shanja-Grabarz Xhesika , Cristofano Francesca Di , Gavathiotis Evripidis , Cristofano Antonio Di
Published: August 2019

Despite recent advancements in chemotherapy and radiation, anaplastic thyroid cancer (ATC) remains an almost invariably lethal disease with an average life expectancy of 2-6 months. Current interventions, including surgery are palliative, underlining the urgent need for novel, effective approaches.

Targeting the apoptosis pathway using BH3 mimetics is effective in hematologic malignancies. However, in solid tumors, the response to these compounds is usually limited and short-lived. In addition, most ATCs have lost p53, resulting in a significant dampening of the pro-apoptotic signals deriving from chemotherapy or radiation.

We hypothesized that a small molecule that directly binds to and activates BAX, bypassing the need for upstream activating signals, might effectively induce apoptosis in ATC cells.

We used a novel activator, EGAV1, that is derived from the previously described BTSA1 molecule, and a panel of 10 ATC cell lines, representing the entire mutation spectrum observed in patients.

We generated dose-response profiles of these cell lines both in traditional 2D cell cultures and in 3D spheroid cultures, and found that EGAV1 induces prompt apoptosis in all cell lines. However, co-immunoprecipitation assays showed that EGAV1-activated BAX can still be sequestered by BCL-XL, which may reduce its efficacy.

Thus, we tested the ability of the BH3 mimetic Navitoclax (ABT-263) to increase EGAV1 efficacy by inhibiting BCL-XL and BCL2.

In fact, we found a dramatic decrease in the EGAV1 IC50 in the presence of a low dose of Navitoclax that has no effect as single agent. Also, we found that the efficacy of Navitoclax was equally amplified by a low dose of EGAV1.

Time-course analysis of caspase 3/7 activity confirmed that these compounds induce prompt apoptosis, peaking between four and eight hours after treatment.

Taken together these data suggest that there is an important therapeutic opportunity in targeting the apoptosis pathway in ATC with a BAX activator accompanied by a BH3 mimetic.

Citation Format: Xhesika Shanja-Grabarz, Francesca Di Cristofano, Evripidis Gavathiotis, Antonio Di Cristofano. Direct BAX activation effectively induces apoptosis in anaplastic thyroid cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr LB-089.
Abstract LB-090: Molecular and pharmacological characterization of mutant NRAS dependency in melanoma cell lines
Authors: Mehta Anita K. , Hua Kevin , Gadrey Jayant , Fuller Angelina , Singh Anurag
Published: August 2019

Oncogenic NRAS mutations are found in 20 percent of sporadic melanoma cases. Mutant NRAS activates the RAF/MEK/ERK mitogen-activated protein kinase (MAPK), PI3K/AKT and RAC1/PAK kinase signaling pathways, which cooperate to drive melanomagenesis. The complexity of the NRAS signaling network presents a challenge to develop effective therapeutics for NRAS mutant melanoma. Many inhibitors of NRAS-regulated signaling pathways, such as BRAF and MEK/ERK inhibitors are ineffective in this setting. Furthermore, direct NRAS inhibition is pharmacologically challenging. It is likely that combined inhibition of two or more nodes in the NRAS signaling network will be effective in treating NRASmutant melanoma. We have used whole-genome transcriptional profiling coupled with phenotypic characterization of NRAS dependency to derive an NRAS dependency gene expression signature. The signature reveals two key features: (1) NRAS dependency is associated with an kinase-regulated inflammatory gene expression program and (2) expression of the melanocyte lineage factor MITF is strongly associated with NRAS-independent cell proliferation. Based on this knowledge, we have identified combinatorial therapeutic modalities to target either NRAS-dependent or NRAS-independent melanoma subtypes. NRAS-dependent melanoma cell lines undergo apoptotic cell death upon combined inhibition of PAK kinases and Bcl2/Bcl-XL proteins. Conversely, NRAS-independent cell lines are sensitive to the apoptotic effects of combined CDK2 and ERK kinase inhibition. Notably, CDK2 is an MITF transcriptional target gene that mediates a feed-forward loop to potentiate MITF activation. Taken together, our studies highlight phenotypic variations in NRAS mutant melanomas that can be exploited to identify subtype-specific therapeutic targets for NRAS mutant melanoma.

Citation Format: Anita K. Mehta, Kevin Hua, Jayant Gadrey, Angelina Fuller, Anurag Singh. Molecular and pharmacological characterization of mutant NRAS dependency in melanoma cell lines [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr LB-090.
Abstract LB-091: Tumor suppressor WW domain-containing oxidoreductase controls epidermal keratinocyte growth
Authors: Hsu Li-Jin
Published: August 2019

Human fragile WWOX gene encodes a candidate tumor suppressor WW domain-containing oxidoreductase. Ectopically overexpressed WWOX protein induces apoptosis in cancer cells and suppresses tumor growth both in vitro and in vivo. Functional suppression of WWOX by antisense mRNA, dominant negatives, and small interfering RNA protects cells from apoptosis induced by tumor necrosis factor, anticancer drugs, UV light, and ectopic p53 in vitro. Interestingly, substantial studies have revealed that progression of various cancers to a pre-metastatic stage positively correlates with upregulation of WWOX protein expression, suggesting that WWOX may act more than a tumor suppressor. In normal human epidermis, WWOX is abundant in proliferating epithelial cells of the skin, and its expression is increased in intensity toward the superficial layers. In this study, we determined a reduced number of Ki67-positive proliferating keratinocytes in the epidermis of our newly developed Wwox gene knockout (Wwox-/-) mice. A marked reduction in the basal (K5-positive) and suprabasal (K10-positive) keratinocyte numbers was examined in the keratinized squamous epithelium of the Wwox-/- mouse skin. Apparent decreases in Wwox-/- epidermal and dermal thickness were found. To further verify whether WWOX regulates keratinocyte growth, we detected significantly decreased cell proliferation in both Wwox-/- primary keratinocyte cultures and WWOX-knockdown HaCaT cells as compared to the control cells. No significant increases in the number of TUNEL-positive cells were observed in the Wwox-/- epidermal tissues. Taken together, our results clearly demonstrated a crucial role of tumor suppressor WWOX in regulating normal keratinocyte proliferation for maintaining skin homeostasis.

Note: This abstract was not presented at the meeting.

Citation Format: Li-Jin Hsu. Tumor suppressor WW domain-containing oxidoreductase controls epidermal keratinocyte growth [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr LB-091.
Abstract LB-104: Epigenetic and transcriptional alterations as potential vulnerabilities of diffuse intrinsic pontine glioma (DIPG)
Authors: Yu Jia-Ray , LeRoy Gary , Stafford James , Lee Chul-Hwan , Reinberg Danny
Published: August 2019

A methionine substitution at lysine-27 on histone H3 variants (H3K27M) is present in more than 80% of diffuse intrinsic pontine gliomas (DIPG) and inhibits polycomb repressive complex 2 (PRC2) in a dominant-negative fashion. We discovered that a number of parameters were involved in H3K27M-dependent inhibition of PRC2, including the ratio between H3K27M and PRC2 present in vivo, an enhanced affinity between H3K27M and the allosterically activated state of PRC2, and the displacement of PRC2 from chromatin containing H3K27M. Following these early events upon an introduction of H3K27M into wildtype cells, the steady-state chromatin manifested a global loss of H3K27 methylation but a gain of H3K36 methylaiton, an antagonistic histone modification associated with transcriptional elongation. These observations suggested that H3K36 methylation may function in displacing PRC2 from chromatin and the oncogenic transcription facilitated by H3K36 methylation could be a vulnerability of H3K27M DIPG. Indeed, ectopic expression of H3K36M in H3K27M DIPG cells depleted global H3K36 methylation and exerted an anti-proliferative effect, implicating a potential strategy in targeting the writer and reader proteins for H3K36 methylation against H3K27M DIPG.

Citation Format: Jia-Ray Yu, Gary LeRoy, James Stafford, Chul-Hwan Lee, Danny Reinberg. Epigenetic and transcriptional alterations as potential vulnerabilities of diffuse intrinsic pontine glioma (DIPG) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr LB-104.
Abstract LB-115: Preclinical assessment of retinoid X-receptor agonist, UAB110, for potential treatment of cutaneous T-cell lymphoma
Authors: Chou Chu-Fang , Esla Jason , Atigadda Venkatram , Muccio Donald , Grubbs Clinton , Craig Elmets , Chang Pi-Ling
Published: August 2019

Cutaneous T-cell lymphomas (CTCLs) are a group of non-Hodgkin diseases characterized by localization of neoplastic T-cells in the skin. The most common forms of CTCLs are mycosis fungoides (MF) and Sézary syndrome (SS). Bexarotene (Targretin®) is currently the only FDA approved retinoid X receptor (RXR) -selective agonist (rexinoid) for the treatment of CTCLs. Despite its low toxicity compared to retinoids and other chemotherapeutic agents, it induces hypothyroidism and markedly elevates serum triglycerides (TGs). Thus, improved rexinoids for the treatment of this indolent disease is necessary. A potential candidate is the novel rexinoid, UAB110, which does not elevate TGs in animal studies and effectively prevents mammary cancer development. Compared to bexarotene, it has higher binding affinity for RXRα receptor and transcriptional activation activity. The purpose of this study is to assess preclinical efficacy, mechanism of action of UAB110, and compare its action with bexarotene and the rexinoid 9-cisUAB30 (UAB30) using human-derived CTCL cell lines, MyLa and HuT78, which are representative of MF and SS, respectively. Cell proliferation analysis and cell-cycle related markers were determined by hemocytometer and Western blot analysis, respectively. UAB110 is as effective as UAB30 and bexarotene in suppressing cell proliferation. Furthermore, it significantly (p < 0.05 relative to DMSO control) suppresses the protein expression of SKP2 (S-phase kinase-associated protein 2, a F-box protein that targets p27kip1 for degradation by 26S proteasome) and PSMA7 (proteasome subunit alpha type 7, a component of the 20S proteolytic complex in 26S proteasome). The decrease in SKP2 resulted in a concomitant up-regulation of p27kip1 protein, the major cell cycle inhibitor. The downregulating of PSMA7 impaired the 20S proteasome activity in both cell lines. These findings indicate that the novel rexinoid is effective in inhibiting cell proliferation of CTCL cells, in part, by suppressing SKP2 expression and the 20S proteasome activity resulting in increasing p27kip1 protein. In sum, UAB110 and also UAB30 with minimal effect in elevating serum TGs are both possible alternatives to bexarotene for the treatment of CTCLs.

Citation Format: Chu-Fang Chou, Jason Esla, Venkatram Atigadda, Donald Muccio, Clinton Grubbs, Elmets Craig, Pi-Ling Chang. Preclinical assessment of retinoid X-receptor agonist, UAB110, for potential treatment of cutaneous T-cell lymphoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr LB-115.
Abstract LB-126: S100A14 promotes breast cancer metastasis via CCL2 dependent macrophage recruitment
Authors: Chen Hongyan , Li Xukun , Liu Zhihua
Published: August 2019

S100A14 is a member of S100 calcium-binding protein family. Our previous studies have reported that S100A14 modulates a variety of tumorigenic processes by functioning both as intracellular and extracellular factors. Emerging evidence indicated that the biology of most S100 proteins is complex and multifactorial. Herein, we identify S100A14 is upregulated in Lymph Node (LN) metastasis breast cancer (BC) and associated with LN metastasis and prognosis. Through gain and loss of function approaches, we find that S100A14 promotes cell migratory and invasive capabilities in vitro and lung metastasis in vivo. More convincingly, S100A14 knockout also suppresses the lung metastases without affecting the primary tumor growth in MMTV-PyMT mouse models. Using a combination of iTRAQ based quantitative proteomics and transcriptomics, we identified CCL2 as a downstream target of S100A14. Importantly, systemic delivery of anti-CCL2 antibody significantly inhibited S100A14-enhanced cell migration and invasion, tumor-associated macrophages (TAMs) accumulation and lung metastasis. Finally, we indicated that the increased serum S100A14 levels could be used for the detection of BC and the prediction of LN metastases. These findings provide a plausible mechanism for S100A14-modulated tumor microenvironment in metastasis and show that S100A14-mediated CCL2 signaling plays a prominent role in breast cancer metastasis, which may have clinical implications for providing novel biomarkers and potential therapeutic targets of breast cancer in future.

Note: This abstract was not presented at the meeting.

Citation Format: Hongyan Chen, Xukun Li, Zhihua Liu. S100A14 promotes breast cancer metastasis via CCL2 dependent macrophage recruitment [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr LB-126.