bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 2100: Deep learning can predict microsatellite instability from histology in colorectal cancer across different ethnic groups
Authors: Pressman Isaiah S. , Xu Hongming , Kang Jeonghyun , Cha Yoon Jin , Lee Sung Hak , Hwang Tae Hyun
Published: September 2020

Microsatellite instability (MSI) is known to be an important genomic marker for prediction of a patient's response to immune checkpoint inhibitors across various types of cancer. Conventional methods to measure DNA mismatch repair (MMR) status are pCR-based panel sequencing or immunohistochemical staining based methods. Recently, deep learning has been proposed as an efficient diagnostic tool in this regard, as it can learn to predict MSI directly from H&E stained slides. However, it is thought that deep learning may not generalize effectively beyond the ethnicities present in the training dataset. Therefore, we investigated the impact of ethnic differences on deep learning performance at MSI classification across a range of model architectures and hyperparameters.

A total of 360 WSIs from a subset of the TCGA colorectal cancer (TCGA set) and another 170 WSIs from Gangnam Severance Hospital (Yonsei University College of Medicine, Seoul, Republic of Korea, Gangnam set) were included in this study. 360 H&E stained WSIs from TCGA set were divided into a set of square tiles of size 256x256um (0.5um/pixel) and then color normalized using Macenko normalization. Those tiles were divided into two classes - MSI-H and MSS (Microsatellite stable) based on the patient's MSI status. We trained various models on those tiles using a range of hyperparameters including model architecture, number of trainable layers, learning rate, and learning rate scheduling. The performance of this model was measured using the AUROC in the TCGA set (internal validation) and Gangnam set (external validation).

Our results for ResNet18 - a popular convolutional network architecture - on TCGA and Gangnam test datasets are around 0.79 and 0.76 respectively, with a standard deviation on Gangnam of 0.03. Given good hyperparameters and model architecture, the model's performance on the Gangnam test data was within one standard deviation of its performance on the TCGA test data, despite the fact that said model was trained using only the TCGA data containing few asian patients. The lack of a significant performance difference challenges the notion that there are morphological differences in colorectal cancers between patients of Caucasian and Asian ethnicities that would prevent a deep learning system from generalizing effectively.

Citation Format: Isaiah S. Pressman, Hongming Xu, Jeonghyun Kang, Yoon Jin Cha, Sung Hak Lee, Tae Hyun Hwang. Deep learning can predict microsatellite instability from histology in colorectal cancer across different ethnic groups [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 2100.
Abstract 2137: A high proportion of protein phosphorylation sites identified in CPTAC breast cancer and lung adenocarcinoma may result from direct phosphorylation by CDK1
Authors: Wang Dunrui , Qian Xiaolan , Eng Sarah , Jenkins Lisa , Durkin Marian , Lowy Douglas
Published: September 2020

Cyclin-dependent kinase 1 (CDK1) is a serine/threonine kinase that drives the G2/M phase of the cell cycle, and increased CDK1 kinase activity is a frequent feature of several tumor types. In the current study, we have used the National Cancer Institute's Clinical Proteomic Tumor Analysis Consortium (CPTAC) datasets to identify potential target phosphorylation sites associated with CDK1 activity in breast and lung adenocarcinoma and to experimentally study some of their biologic effects. Among the global protein phosphorylation sites detected in CPTAC, 80% and 81% of the identified phosphorylation sites in breast cancer and lung adenocarcinoma were found to correlate well with the level of an activating phosphorylation site in CDK1, t161. Positive correlations (r > 0.6) were present in most paired samples of tumor tissue and normal tissue. In addition, 42% and 40% of all phosphorylation sites in both of these tumor types were found to contain the minimum CDK1 consensus motif Ser/Thr-Pro (S/T-P). This result suggests that many of the sites with this motif are directly phosphorylated by CDK1, while most of the sites that lack this sequence are likely to be phosphorylated by other kinases. In both tumor types, increased phosphorylation of proteins in several signaling pathways, including those for glycolysis and the cell cycle, were found to be associated with phosphorylation of CDK1 t161. To study a possible direct effect of CDK1-dependent phosphorylation on a protein involved in cell cycle progression, we selected Epithelial Cell Transforming 2 (ECT2), which is a Rho family-specific GEF (guanine nucleotide exchange factor) with a role in G2/M. In agreement with the proteomic data, mass spectrometry analysis showed elevated ECT2 phosphorylation on T359, S367, T373, S376 and S861 in the G2/M phase that was sensitive to treatment with a CDK1 inhibitor. Biological experiments confirmed that phosphorylation of these sites enhanced the pro-oncogenic and GEF activity of ECT2. Additional experimental mechanistic analysis is needed to demonstrate whether specific phosphorylations are attributable to direct or indirect effects of CDK1.

Citation Format: Dunrui Wang, Xiaolan Qian, Sarah Eng, Lisa Jenkins, Marian Durkin, Douglas Lowy. A high proportion of protein phosphorylation sites identified in CPTAC breast cancer and lung adenocarcinoma may result from direct phosphorylation by CDK1 [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 2137.
Abstract 2220: Non-clinical tumor models reveal broad combination potential of ICOS agonist antibodies
Authors: Waight Jeremy D. , Bi Meixia , Kilian David , Hopson Christopher , Zhang Shu-Yun , Brett Sara , Yadavilli Sapna , Zhang Tianqian , Shi Hong , Hance Kenneth W. , Ballas Marc , Hoos Axel
Published: September 2020

Unprecedented rates of durable clinical responses have been observed for antibody-based therapeutics targeting immune checkpoint proteins such as cytotoxic T lymphocyte antigen-4 (CTLA-4) or programmed death receptor-1 (PD-1). Nonetheless, a significant number of patients fail to respond, highlighting the need for alternative and complementary immunotherapeutic interventions for cancer. Inducible T-cell costimulator (ICOS/CD278) is a CD28 superfamily receptor that is predominantly expressed on effector and cytotoxic T cells shortly after T cell receptor (TCR) activation. In addition to promotion of T cell and B cell collaboration, ICOS signaling (via ICOS ligand [ICOSL] or antibody-based crosslinking) has been shown to improve T cell antitumor activity, survival, durable tumor rejection. To support the clinical development of GSK3359609 (a hIgG4 ICOS agonist antibody) several in vivo combination studies were conducted using a tool anti-mouse ICOS agonist antibody (clone 7E.17G9). Analogous with the Fc-based characteristics of a human IgG4 antibody, the anti-mouse ICOS tool antibody exhibited significant antitumor activity when grafted on a murine IgG1 (or Fc-reduced) backbone. Using an in vivo models of breast cancer (EMT6, BALB/c), the murinized ICOS tool antibody demonstrated potent antitumor activity alone (tumor growth inhibition [TGI] of 40-60%) in combination with immune checkpoint inhibitors (ICI) targeting PD-1 and CTLA-4 (TGI of 100% and 90%, respectively). Antitumor activity was associated with increased total T cell infiltration into the tumor, a higher tumor CD8/Treg cell ratio, and broad increases in T cell activation markers (e.g. CD25, CD69, Granzyme B, perforin, and PD-1). The cancer immunity cycle posits that multiple points of intervention exist for cancer immunotherapy, many of which should be considered in order to identify complementary therapeutic strategies. With this in mind, and consistent with ICI, antitumor activity was observed in combination with innate immune modulators (e.g. TLR4 agonist) and chemo/cytotoxic (e.g. carboplatin and paclitaxel) therapies in different syngeneic tumor models. Altogether these data underscore the broad utility of ICOS agonist antibodies as a reliable combination partner for cancer immunotherapy.

Citation Format: Jeremy D. Waight, Meixia Bi, David Kilian, Christopher Hopson, Shu-Yun Zhang, Sara Brett, Sapna Yadavilli, Tianqian Zhang, Hong Shi, Kenneth W. Hance, Marc Ballas, Axel Hoos. Non-clinical tumor models reveal broad combination potential of ICOS agonist antibodies [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 2220.
Abstract 2589: Dysregulation of RalGAPA2 in hepatocellular carcinoma
Authors: Tian Lu , Chan Lo Kong , HO Daniel Wai Hung , Zhao LuQing , NG Irene Oi Lin
Published: September 2020

RalGTPases are Ras-like G-proteins which cycle between the active GTP-bound and the inactive GDP-bound forms. Elevation of expression and activity of RalGTPase has been demonstrated to play an oncogenic role in human cancers. RalA activity could be positively regulated by RalGEF and negatively regulated by RalGAP. The functional RalGAP complex consists of either one of the catalytic subunits, RalGAPA1 or RalGAPA2, together with the regulatory subunit, RalGAPB. In this study, we aimed to investigate the potential role of RalGAPA2 dysregulation and its functional significance in hepatocellular carcinoma (HCC). By RNA-sequencing analysis in human HCC tissues and cell lines, we found that RalGAPA2 was the predominantly expressed RalGAP catalytic subunit in the liver. To examine the RalGAPA2 expression in HCC, we performed qPCR analysis in paired HCC tissues (n=90), and 37.8% of the HCC samples showed a 2-fold downregulation of RalGAPA2. Clinically, downregulation of RalGAPA2 was significantly correlated with a lower cellular differentiation (P=0.034) and a shorter overall survival rate (P=0.045). Interestingly, HCC tumors showing combined upregulation of RalA and downregulation of RalGAPA2 tended to be associated with more aggressive tumor behaviour, including higher occurrence of venous invasion (P=0.001) and more advanced TNM stage (P=0.007). On the other hand, by targeted-DNA sequencing, RalGAPA2 was identified to be recurrently mutated in 7.4% of the patients in a HBV-associated HCC cohort (n=95). Functionally, CRISPR/Cas9-mediated RalGAPA2 knockout HCC cells showed an enhanced migratory ability when compared to the control cells, underlying an upregulation of RalA activity. In HCC, expression of RalA isoform was found to be specifically upregulated and functionally supporting HCC metastasis. Also, inhibition of RalGAP has been demonstrated to promote RalA activity and enhance cell invasion in several cancer types, including oral squamous cell carcinoma, prostate and bladder cancer. Consistently, the inverse correlation between the RalA activity and RalGAPA2 expression was also observed in a panel of HCC cell lines. Furthermore, HCC cells possessing a higher RalA activity were demonstrated to be more prone to RBC8 treatment, a RalGTPase-specific inhibitor. Taken together, our results suggested that RalGAPA2 might play a potential tumor suppressive role in HCC by negatively regulating RalA activity.

Citation Format: Lu Tian, Lo Kong Chan, Daniel Wai Hung HO, LuQing Zhao, Irene Oi Lin NG. Dysregulation of RalGAPA2 in hepatocellular carcinoma [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 2589.
Abstract 2856: An intelligent boosting to amplify signal with isobaric labeling (iBASIL) strategy for precise quantitative single-cell proteomics analysis
Authors: Tsai Chia-Feng , Zhao Rui , Moore Ronald , Williams Sarah , Schultz Kendall , Piehowski Paul , Pasa-Tolic Ljiljana , Rodland Karin , Smith Richard , Shi Tujin , Zhu Ying , Zhu Ying , Liu Tao
Published: September 2020

Mass spectrometry (MS)-based proteomics has great potential for overcoming the limitations of antibody-based immunoassays for antibody-independent, comprehensive, and quantitative proteomic analysis of single cells. Indeed, recent advances in nanoscale sample preparation have enabled effective processing of single cells. In particular, the concept of using boosting/carrier channels in isobaric labeling to increase the sensitivity in MS detection (e.g., our recent boosting to amplify signal with isobaric labeling (BASIL) approach) has also been increasingly used for quantitative proteomic analysis of small-sized samples including single cells. However, the full potential of such boosting/carrier approaches has not been significantly explored, nor has the resulting quantitation quality been carefully evaluated. Herein, we have systematically evaluated and optimized the BASIL approach, originally developed for quantifying phosphorylation in small number of cells, for highly effective analysis of single cells. This improved, intelligent BASIL (iBASIL) approach enables comprehensive and quantitative single-cell proteomics analysis by carefully controlling the boosting-to-sample ratio and optimizing MS automatic gain control and ion injection time settings. Using standard LC-MS platforms, iBASIL enabled precise quantification of 800-1,200 proteins from single FACS-isolated cells (depending on the cell type). Moreover, coupling iBASIL to nanoscale fractionation enabled identification of >3,000 proteins and reliable quantification of >2,000 proteins while readily separating single cells from 3 different acute myeloid leukemia cell lines. We believe iBASIL has broad utility for comprehensive and precise quantitative single-cell proteomics for systems biology and biomedical research, as well as for comprehensive proteomic analysis of size-limited clinical specimens that cannot be readily accessed by regular proteomics platforms. It also has the potential to be adapted for phosphoproteome analysis of as few as 100 cells.

Citation Format: Chia-Feng Tsai, Rui Zhao, Ronald Moore, Sarah Williams, Kendall Schultz, Paul Piehowski, Ljiljana Pasa-Tolic, Karin Rodland, Richard Smith, Tujin Shi, Ying Zhu, Ying Zhu, Tao Liu. An intelligent boosting to amplify signal with isobaric labeling (iBASIL) strategy for precise quantitative single-cell proteomics analysis [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 2856.
Abstract 2885: Discovery of a tripeptide-based camptothecin drug-linker for antibody-drug conjugates with potent antitumor activity and a broad therapeutic window
Authors: Lyski Ryan , Bou Lauren , Zaval Margo , Emmerton Kim , Okeley Nicole , Simmons Jessica , Zapata Francisco , Ortiz David , McKinney Erica , Meyer David , Ryan Maureen , Senter Peter , Jeffrey Scott
Published: September 2020

In efforts to bring forward antibody-drug conjugate (ADC) technologies that complement vedotin and enable new clinical-stage ADCs, we have investigated compounds that interact with topoisomerase 1, an enzyme involved in the unwinding of DNA. In connection with this, we developed a highly active and well-tolerated camptothecin drug-linker technology, in which the lead molecule consists of 7-aminomethyl-10,11-methylenedioxycamptothecin (AMDCPT) attached to a protease-cleavable valine-lysine-glycine (VKG) tripeptide linker unit. A hydrophilic and discrete polyethylene glycol unit was included to improve the properties of the drug-linker, enabling high ADC drug-loading, and reducing the propensity for aggregation. A VKG-AMDCPT ADC, with 8 drug-linkers/mAb (DAR8), displayed a pharmacokinetic profile coincident with parental unconjugated antibody, with a high degree of stability against retro-Michael reaction deconjugation. ADCs based on the VKG-AMDCPT were broadly active against cancer cells in vitro, and in mouse xenograft models, giving tumor regressions and complete responses with a single ≤3 mg/kg dose. These included both solid and hematologic tumor models, and models of bystander killing activity and multidrug resistance. A non-binding DAR8 ADC was well-tolerated in rats at 60 mg/kg, q7dx4. The VKG-AMDCPT drug-linker can be prepared from available materials in eight high-yielding steps, and this drug-linker is being employed in the anti-CD30 ADC, SGN-CD30C; an investigational new drug application is planned for 2020.

Citation Format: Ryan Lyski, Lauren Bou, Margo Zaval, Kim Emmerton, Nicole Okeley, Jessica Simmons, Francisco Zapata, David Ortiz, Erica McKinney, David Meyer, Maureen Ryan, Peter Senter, Scott Jeffrey. Discovery of a tripeptide-based camptothecin drug-linker for antibody-drug conjugates with potent antitumor activity and a broad therapeutic window [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 2885.
Abstract 2895: Characterization of payload release from a novel camptothecin drug-linker
Authors: Cochran Julia H. , Farr Lauren , Lyski Ryan , Senter Peter D. , Jeffrey Scott C. , Hengel Shawna M. , Okeley Nicole M.
Published: September 2020

Camptothecins (CPT) are an important class of molecules that have been employed in cancer therapy for the past 20 years. These molecules interact with the DNA-topoisomerase I complex leading to double-strand breaks and cell death. While these molecules are important cancer therapies, they also induce toxicities including diarrhea and myelosuppression. Antibody-drug conjugates (ADCs) have emerged as a method to help mitigate small molecule toxicities by targeting them to tumors via conjugation to tumor-specific antibodies. Recently, encouraging clinical results have been observed with ADCs bearing CPT payloads, demonstrating a potential new utility for this class. The linker that is used to conjugate a payload to an ADC influences its activity, by controlling the identity of the molecular species that can be released, as well as efficiency of drug release. When employed as an ADC, maleimidopropionyl-PEG7-valine-lysine-glycine-7-aminomethyl-10,11-methylenedioxycamptothecin (VKG-AMDCPT), a novel, highly active and enzyme-cleavable tripeptide CPT drug-linker, releases two CPT payloads in cancer cells, as demonstrated both in vitro and in vivo. Using tandem mass spectrometry (LC-MS/MS), the two CPTs have been identified as 7-amino methyl 10,11-methylenedioxy CPT (AMDCPT) and the corresponding glycine adduct of AMDCPT (G-AMDCPT). We have characterized the efficiency of drug release and intracellular retention of the small molecules released from VKG-AMDCPT-conjugated ADCs. This was accomplished through quantification of each species released in vitro and in vivo using multiple cancer cell lines and xenografts. We report here characterization of the biochemical, cellular and bystander killing potencies of each released drug species to further understand their contributions to ADC activity.

Citation Format: Julia H. Cochran, Lauren Farr, Ryan Lyski, Peter D. Senter, Scott C. Jeffrey, Shawna M. Hengel, Nicole M. Okeley. Characterization of payload release from a novel camptothecin drug-linker [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 2895.
Abstract 2932: CD59 facilitates tumor progression through activating TGF-β/Smad signaling pathway in hepatocellular carcinoma
Authors: Lan Tian , Wu Hong
Published: September 2020

Little success has been achieved in the exploitation of effective interventions against hepatocellular carcinoma (HCC) pathogenesis. To determine the crucial regulators in this process, CD59 was identified from the lung metastasis screening mice models that we previously reported. It is well known that CD59, belonging to membrane-bound complement regulatory proteins (mCRPs), acts as a suppressor of the formation of the membrane attack complex to enable tumor cells to escape from complement surveillance. Apart from that, our work identified CD59 as a potential oncogenic driver in hepatocarcinogenesis and metastasis. Specifically, CD59 was considerably upregulated in HCC tissues. High expression of CD59 was associated with poor overall survival and disease-free survival. Functional studies demonstrated that CD59 knockdown inhibited proliferation, cell cycle and apoptosis resistance of HCC cells, impaired their tumorigenic and metastasis capacities in vitro and in vivo, whereas overexpression of CD59 exhibited opposite cell phenotypes. Mechanistically, CD59 competitively binds to aminoacyl tRNA synthetase complex interacting multifunctional protein 1 (AIMP1), resulting in the disassociation of AIMP1 from Smad-specific E3 ubiquitin protein ligase 2 (Smurf2) and the continuous interaction between Smurf2 and Smad7, thus accelerating the ubiquitin-mediated degradation of Smad7. By contrast, loss of CD59 promoted excessive Smad7 formation, leading to the abolishment of Smad2/3 phosphorylation and subsequent nuclear translocation, therefore inhibiting hepatocarcinogenesis and metastasis. Overall, our findings indicated that CD59 facilitated HCC pathogenesis via modulating TGF-β signaling, apart from disturbing the complement-dependent cytotoxicity. CD59 may be an effective prognostic biomarker and potential therapeutic target for HCC.

Citation Format: Tian Lan, Hong Wu. CD59 facilitates tumor progression through activating TGF-β/Smad signaling pathway in hepatocellular carcinoma [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 2932.
Abstract 3042: Anti-cancer efficacy of an anti-ErbB3 antibody, ISU104, against the cancers with NRG1-overexpression, NRG1-fusion, or oncogenic ErbB3 mutations
Authors: Hong Seung-Beom , Hong Mirim , Kim Tae-Eun , Kim Ju Yeon , Kim Jung Won , Cho Jeongin , Shin Bongseok , Bae Donggoo
Published: September 2020

ErbB3, a heterodimeric partner of EGFR or ErbB2, plays important roles in the survival and growth of cancer cells through activation of PI3K/AKT pathway. ErbB3 can be activated by NRG1 expressed either by cancer cells or adjacent mesenchymal cells, or NRG1-fusion proteins produced by genetic alterations in cancer cells. Oncogenic driver mutations in ErbB3 also induce its activation. Previously, we have demonstrated preclinical anti-cancer efficacy of a monoclonal anti-ErbB3 antibody, ISU104 as a monotherapy or in combination with anti-EGFR antibody in various preclinical models. Biomarker analysis of the models demonstrated that there is a significant positive correlation between tumor growth inhibition by ISU104 and NRG1 mRNA/pERBB3 protein expression levels. Based on this analysis, anti-cancer efficacy of ISU104 was further explored in cancer cells and cell line- or patient-derived xenograft cancer models with high NRG1 expression, NRG1-fusion or oncogenic ErbB3 mutations. ISU104 potently inhibited phosphorylation of ERBB3 and AKT, cell proliferation and tumor growth of such models. Potential impacts of other genetic alterations on the anti-cancer efficacy of ISU104 were also investigated. Overall, the presented data suggest that ISU104, an anti-ErbB3 agent in the early stage of clinical development, can be applied for the treatment of the solid tumors expressing high level of NRG1 or harboring genetic alterations such as NRG1-fusion or oncogenic ErbB3 mutations.

Citation Format: Seung-Beom Hong, Mirim Hong, Tae-Eun Kim, Ju Yeon Kim, Jung Won Kim, Jeongin Cho, Bongseok Shin, Donggoo Bae. Anti-cancer efficacy of an anti-ErbB3 antibody, ISU104, against the cancers with NRG1-overexpression, NRG1-fusion, or oncogenic ErbB3 mutations [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 3042.
Abstract 309: Mapping oncogenic signal transduction in PKA-driven cancers
Authors: Chan Gary Kwan Leung , Maisel Samantha M. , Hwang Y. Christina , Wolber Rebecca , Swaney Danielle L. , Bardeesy Nabeel , Gordan John D.
Published: September 2020

Protein Kinase A (PKA) is a major effector of cyclic-AMP (cAMP) signaling and has recently been appreciated to play a role in multiple malignancies. Mutations of its catalytic subunit (PRKACA) have been identified in a substantial proportion of adrenocortical tumors, and are also detected in a wide spectrum of tumor types in the TCGA dataset, although at a low frequency. A unique fusion protein of PRKACA and DNAJB1 is seen in the majority of fibrolamellar liver cancers (FLC), a rare malignancy of young adults, where it is suspected to be the primary oncogenic driver. However, the key effectors of oncogenic signaling in FLC and other PRKACA driven cancers remain unknown. To understand PKA's downstream targets, we generated genetic cell models with doxycycline-inducible PRKACA or its dominant negative counterpart, a mutant form of the PRKAR1A regulatory subunit. These cell models were then subjected to mass spectrometry for kinome profiling in order to detect kinases with significant altered activity following PKA modulation. This was integrated with small molecule inhibition and siRNA knockdown to identify PKA-regulated kinases that impact cell proliferation. Our analysis revealed activation of the aurora-family kinase AURKA, with preferential sensitivity to the confirmation-disrupting AURKA inhibitor (CD-AURKAi) CD532 compared to other AURKA inhibitors. CD-AURKAi not only selectively inhibit AURKA's kinase activity, but also disrupt its interaction with MYC-family transcription factors. These key oncogenic mediators are necessary to drive the proliferation of multiple tumor types, although they have not yet been connected with oncogenic PKA signaling. Our follow up quantitative PCR experiments confirm that CD-532 treatment results in reduced expression of MYC family members and their transcriptional targets. We next confirmed that MYC family members support the proliferation of PKA-driven cell models with live cell imaging. Finally, we have begun to investigate other kinases identified in our siRNA screen for potential effects on MYC, and have identified several potential combination partners to augment the activity of CD-532 and other CD-AURKAi. These data suggest that CD-AURKAi, either alone or in combination, have the potential to serve as therapeutic agents for PKA-driven cancers.

Citation Format: Gary Kwan Leung Chan, Samantha M. Maisel, Y. Christina Hwang, Rebecca Wolber, Danielle L. Swaney, Nabeel Bardeesy, John D. Gordan. Mapping oncogenic signal transduction in PKA-driven cancers [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 309.
Abstract 3432: Zinc metallochaperones for mutant p53 reactivation in cancer therapeutics
Authors: Yu Xin , Na Bing , Zaman Saif , Withers Tracy , Gilleran John , Blayney Alan J. , Bencivenga Anthony F. , Blanden Adam R. , Liu Yue , Boothman David A. , Loh Stewart N. , Kimball S. David , Ganesan Shridar , Carpizo Darren R.
Published: September 2020

The p53 transcription factor functions as one of cancer's most potent tumor suppressors and is the most frequently mutated gene in human cancer. Restoration of wild type structure and function (so-called reactivation) of the high levels of the deficient mutant p53 protein with a small molecule is a highly sought after goal in anti-cancer drug development. We discovered a new class of small molecule zinc chelators named zinc metallochaperones (ZMCs) that reactivate zinc deficient mutant p53 through a novel mechanism by refolding p53 protein and inducing a p53 mediated apoptotic program. We identified the role of cellular zinc homeostasis as the OFF switch in ZMC pharmacodynamics indicating that a brief period of p53 mutant reactivation is sufficient for on-target efficacy. We conducted pre-clinical pharmacokinetic (PK), pharmacodymanic (PD) and efficacy studies in the murine pancreatic cancer (KPC) and BRCA1-deficient breast cancer models and found that ZMC1 and its new formulation of the drug in complex with zinc improved survival and inhibited tumor growth specifically for the zinc deficient allele. Using the BRCA1-deficient breast cancer model, we observed a highly synergistic effect of ZMC1 and the PARP inhibitor olaparib. Olaparib is now approved for the treatment of advanced BRCA1/2 mutant ovarian cancers, and recent clinical data also support its efficacy in BRCA1/2 mutant breast cancers. However acquired resistance to PARP inhibitors is inevitable in most advanced cancers. We investigated the ZMC therapeutic efficacy and found that the cell lines derived from olaparib resistant tumors are still sensitive to ZMC1 treatment. We are currently investigating the mechanism and testing the combination in vivo. In addition, we explored synergistic combinations of ZMC1 and other chemotherapy drugs based on its mechanism of action including ZMC1 with MDM2 antagonists and BCL2 antagonists. Overall, our findings indicate that the mutant p53 reactivational activity of ZMCs is governed by a unique ON/OFF switch mechanism that allows the compounds to be effective with a brief exposure to avoid the off target toxicities. The targeted and synergistic combinatorial treatments represent a significant departure from the traditional paradigm for developing a targeted molecular therapeutic in cancer.

Citation Format: Xin Yu, Bing Na, Saif Zaman, Tracy Withers, John Gilleran, Alan J. Blayney, Anthony F. Bencivenga, Adam R. Blanden, Yue Liu, David A. Boothman, Stewart N. Loh, S. David Kimball, Shridar Ganesan, Darren R. Carpizo. Zinc metallochaperones for mutant p53 reactivation in cancer therapeutics [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 3432.
Abstract 3466: Can grape powder supplemented diet prevent prostate cancer progression
Authors: Joshi Tanvi , Patel Ishani , Kumar Avinash , Donovan Virginia , Levenson Anait S.
Published: September 2020

Epidemiological and experimental studies suggest a correlation between diet, particularly fat consumption and the risk of developing prostate cancer (PCa). In previous studies, we reported that stilbenes, namely resveratrol and pterostilbene, restrained prostatic intraepithelial neoplasia (PIN) formation and reduced tumor development and progression in mice models of PCa with high expression of metastasis-associated protein 1 (MTA1), an epigenetic modifier involved in the regulation of prostate cancer progression and metastasis. In this report, we evaluated three major aspects: 1) whether altering diet [low fat diet (LFD) versus high fat diet (HFD)] affects PCa progression; 2) whether grape powder (GP) supplementation to the diets protects against PCa progression, and 3) whether MTA1 targeting is the main mechanism of action. We addressed these questions by utilizing the prostate-specific (PB-Cre4) Pten heterozygous transgenic mice (Pten+/f), which mimic slow-growing PCa progression in humans. Upon accumulating 56 mice of desired genotype, we randomized mice in two major groups and fed them ad libitum with either LFD or HFD. Each of these diets contained either 0% GP or 10% GP supplementation. The same groups were assigned for control wild-type (WT) mice (Pten+/f; Cre-). After 33 weeks on corresponding diets, mice were sacrificed and urogenital system was collected for histological and immunochemical analysis. In addition, protein and RNA was isolated from the prostate tissues for molecular analysis. Blood was also collected for cytokines evaluation and pharmacokinetic analysis. The results demonstrated the following beneficial effects of GP supplementation: LFD and HFD - fed Pten+/f mice showed added favorable histopathology (H&E), intact basal layer (SMA) and luminal cells (CK-8); significant reduction of the proliferative rate of prostate epithelial cells (Ki67); non-significant trend for reducing HFD-induced MTA1 expression in Pten+/f and WT mice; protective effects against “bad” genotype and HFD-induced activation of Akt pathway; attenuation of HFD-associated increase in AR levels in both Pten+/f and WT mice; reduction of HFD-provoked increased inflammation marker IL-1β levels; non-significant trend for reducing angiogenesis (CD31; VEGF-C) in Pten+/f mice; and trend towards decreasing inflammatory TGFβ1 expression in Pten+/f mice. Curious results were obtained concerning the effect of GP on apoptosis. There were no significant changes in body weight, food intake or fat intake in GP supplemented diets groups.

Citation Format: Tanvi Joshi, Ishani Patel, Avinash Kumar, Virginia Donovan, Anait S. Levenson. Can grape powder supplemented diet prevent prostate cancer progression [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 3466.
Abstract 3506: African-specific improvement of a polygenic hazard score to predict age of onset of prostate cancer
Authors: Karunamuni Roshan , Huynh-Le Minh-Phuong C. , Fan Chun C. , Mills Ian G. , Andreassen Ole A. , Dale Anders M. , Seibert Tyler M. ,   The PRACTICAL Consortium
Published: September 2020

Introduction: Polygenic hazard models can be used in predicting age of onset of prostate cancer. A recently published model, PHS46, showed reduced performance in men with African genetic ancestry - the hazard ratio for aggressive prostate cancer in individuals with high values of PHS46 was approximately half as large for those with African genetic ancestry (2.4) as it was for those with European (5.6) or Asian (5.2) ancestry. We used a cross-validated search to identify SNPs that would add statistical value to a base model of PHS46 among African men and help bridge the performance gap in this population.

Material and Methods: Anonymized genotypic data were obtained from 6,253 men with African genetic ancestry from the PRACTICAL consortium. Ten iterations of a ten-fold cross-validation search were conducted, where SNPs were added greedily and stepwise to the PHS46 Cox proportional hazards model using age of onset of any prostate cancer as the dependent variable. Individuals without prostate cancer were censored at age of last follow-up. SNPs were selected for the final, enhanced-PHS46 model if they were selected in more than 50% of the folds. The predictive performances of PHS46 and enhanced-PHS46 were compared using the same cross-validated approach.

Results: Three SNPs (rs76229939, rs74421890, and rs5013678) were selected for inclusion in enhanced-PHS46 model. All three SNPs are located on chromosome 8q.24. Enhanced-PHS46 model showed substantial improvements in all performance metrics measured, including a 20% reduction in the relative hazard of those in the bottom 20% compared to the middle 40% (0.65 to 0.53), a 75% increase in the relative hazard of those in the upper 20% compared to the bottom 20% (2.47 to 4.34) and a 95% increase in the relative hazard of those in the upper 2% compared to the middle 40% (2.1 to 4.1). Similar improvements were demonstrated using the age of onset of aggressive prostate cancer.

Conclusions: We identified three SNPs (rs76229939, rs74421890, and rs5013678) that substantially improved the performance of PHS46 in a dataset of men with African genetic ancestry. A strategy of building on established models might be applied to other groups generally under-represented in genome-wide association studies.

Citation Format: Roshan Karunamuni, Minh-Phuong C. Huynh-Le, Chun C. Fan, Ian G. Mills, Ole A. Andreassen, Anders M. Dale, Tyler M. Seibert, The PRACTICAL Consortium. African-specific improvement of a polygenic hazard score to predict age of onset of prostate cancer [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 3506.
Abstract 3519: Genetically predicted plasma N-glycans and prostate cancer risk: Analysis of over 140,000 European descendants
Authors: Zhao Tianying , Zhu Jingjing , Wu Lang
Published: September 2020

Prostate cancer is the second most frequently diagnosed malignancy among males in many countries. There are critical needs to better understand its etiology and identifying effective biomarkers to improve its early detection. Many proteins are modified by glycans that bind to the proteins, a post-translational modification that are critical for normal physiological processes. Studies have linked dysregulation of glycosylation to several human diseases including prostate cancer. Multiple glycan alterations have been identified to be potentially related to prostate cancer, such as changes to PSA glycosylation, sialylation and core fucosylation, O-GlcNacylation, cryptic and branched N-glyans, as well as galectins and proteoglycans. Limited research, however, has been performed to comprehensively evaluate relationship between N-glycans and prostate cancer. To identify novel N-glycans that are potentially associated with prostate cancer risk, we performed a study using a highly novel and cost-efficient approach.

Using genetic variants reported to be associated with plasma N-glycan levels in large genome-wide associations studies as instruments, we evaluated associations between plasma N-glycans and prostate cancer risk, using the inverse variance weighted method (IVW). Data generated from 79,194 prostate cancer cases and 61,112 controls of European ancestry included in PRACTICAL/ELLIPSE consortia were used in this analysis, providing sufficient power for our research question of interest.

We observed associations between genetically predicted plasma levels of two N-glycans and prostate cancer risk at P<0.05. The odds ratio (OR) and 95% confidence interval (CI) per one standard deviation increase in genetically predicted levels of glycans are: IGP17, 1.05 (1.01-1.10); and IGP41, 0.93 (0.88-0.99). However, these associations became insignificant after adjusting for multiple comparisons.

In conclusion, our agnostic analysis does not identify novel N-glycans whose genetically predicted levels in plasma are associated with prostate cancer risk. Further studies are needed to better characterize the relationship between N-glycans and prostate cancer.

Citation Format: Tianying Zhao, Jingjing Zhu, Lang Wu. Genetically predicted plasma N-glycans and prostate cancer risk: Analysis of over 140,000 European descendants [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 3519.
Abstract 3760: HH2710, a highly potent and selective erk1/2 inhibitor for the treatment of mapk mutant tumors
Authors: Li Lei , Huang Min , Li Leping , Chen Yi , Tang Shuai , Su Yi , Dong Ruiping , Ding Jian , Geng Meiyu
Published: September 2020

The mitogen-activated protein kinases (MAPK) pathway, often known as the RAS-RAF-MEK-ERK signal cascade, is the most frequently mutated signal pathway in cancer, which makes the components of this pathway attractive targets for anticancer drug development. The MAPK pathway is aberrantly activated in more than 30% of human cancers through a high frequency of genetic alteration. BRAF mutation has been identified in colorectal (10%), thyroid (∼50%) and melanoma (60%) tumors, whereas RAS is mutated in melanoma (20%), colorectal (50%) and pancreatic (90%) tumors. Thus far, inhibitors targeting the upstream BRAF and MEK have been the focus of past decades and achieved great clinical successes, but remained being challenged by the acquired resistance due to genetic alterations in RAS, BRAF or MEK. Therefore, targeting the downstream ERK is believed to exhibit potential advantages in both effectively shutting down MAPK signaling cascade and overcoming the resistance to upstream targets. Toward that end, we developed a novel ERK1/2 inhibitor, HH2710, which is a highly potent and selective inhibitor of ERK1 and ERK2 with IC50 of 4.5, 4.9 nM, respectively. HH2710 significantly inhibited the downstream RSK phosphorylation in a dose-dependent manner in both BRAF and RAS mutant cancer cell lines. HH2710 strongly inhibited the proliferation of most BRAF mutated cancer cell and a proportion of RAS mutated cells, with IC50s ranging from 0.2 to 4.5 μM. In tumor xenograft models, HH2710 showed significant antitumor activity at the doses of 15, 30, and 60 mg/kg (twice per day, given orally) with the relative tumor volume at the endpoint (T/C value) of 51.0%, 18.1%, and 11.7% respectively, exhibiting improved efficacy over the front runner molecule in clinical development. Summary of pharmacokinetic parameters are listed in Table 1. The full in vitro and in vivo preclinical characterizations of HH2710 will be presented. Table 1, Pharmacokinetic parameters of HH2710 in mouse, SD rats and Beagle dogs

ParametersnCmax*nAUC0-t*t1/2TmaxFµg/mLµg•h/mLhh(%)Mouse, PO0.5031.811.12.065Rat, PO0.2691.773.02.068Dog, PO0.3381.642.01.573*nCmax: Cmax/dose; nAUC0-t : AUC0-t/dose

Citation Format: Lei Li, Min Huang, Leping Li, Yi Chen, Shuai Tang, Yi Su, Ruiping Dong, Jian Ding, Meiyu Geng. HH2710, a highly potent and selective erk1/2 inhibitor for the treatment of mapk mutant tumors [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 3760.
Abstract 3859: CXCL17 modulates macrophage polarization and immune cell infiltrate in cutaneous squamous cell carcinoma
Authors: Khandelwal Alok R. , Paralikar Ameesha A. , Soleja Rafay Q. , Temple Zachary B. , Robert Madison M. , Alam Maksudul , Nathan Cherie-Ann O.
Published: September 2020

Cutaneous squamous cell carcinoma (cSCC), a keratinocyte-derived invasive and metastatic tumor of the skin, is the second most common form of skin cancer. Exposure to UltraViolet B (UVB) radiation represent a unique risk factors for cSCC development, and the immune system plays a key role in modulating the response. Immunosuppressed patients are at a considerably increased risk for cSCC-induced morbidity and mortality due to its enhanced recurrence and metastatic potential. Novel mechanism-based therapeutics are needed to prevent UVB-induced cSCC. Chemokines are a group of small chemotactic cytokines that can exert extensive and complex effects on cancer via interaction with their receptors. Chemokine (C-X-C motif) ligand 17 (CXCL17) is the latest member of the chemokine family, and recent studies have identified both a causative and suppressive role of CXCL17 and its cognate receptor GPR35 in tumorigenesis. The purpose of the study was to investigate the role of CXCL17 in modulating tumor immune cell infiltrate with primary focus on macrophages. Further, the effect of CXCL17 on macrophage polarization and function was also assessed. Treatment of RAW 264.7 and bone marrow-derived macrophages (BDMC) with CXCL17 increased chemotaxis and polarized the cells towards an M2 phenotype with significant increase in transcriptional levels of Arginase, Fizz and Ym2. Interestingly, CXCL17 also increased transcript level of TNF-alpha in both RAW and BDMC's suggesting a “mixed” M1/M2 phenotype population that may potentially maintain a certain degree of flexibility and adaptability in facilitating tumor survival and resistance to biologic therapies. This “mixed” phenotype is also expected to promote a variety of pro-tumor functions. To further translate our in vitro studies in an in vivo mouse syngeneic cSCC model, SCCB cells were deleted for CXCL17 and injected into the flank of FVB mice. Tumors were collected and subjected to flow cytometry analysis for tumor cell infiltrate. Deletion of CXCL17 significantly decreased macrophage infiltration at the tumor site. Further, decrease in CXCL17 was associated with a reduction in immunosuppressive cells such as Tregs and MDSC suggesting a role for CXCL17 in tumor immune evasion. Our studies underscore the importance of CXCL17 signaling in cSCC and provide a novel target for the treatment of non-melanoma skin cancer.

Citation Format: Alok R. Khandelwal, Ameesha A. Paralikar, Rafay Q. Soleja, Zachary B. Temple, Madison M. Robert, Maksudul Alam, Cherie-Ann O. Nathan. CXCL17 modulates macrophage polarization and immune cell infiltrate in cutaneous squamous cell carcinoma [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 3859.
Abstract 3993: 'Educated' osteoblasts suppress osteoclastogenesis and bone resorption in a bone mimetic microenvironment
Authors: Kolb Alexus D. , Bussard Karen M.
Published: September 2020

Breast cancer (BC) preferentially disseminates to bone. During BC progression in bone, BC cells communicate with osteoblasts (OBs), osteoclasts (OCs), and other stromal cells to shape the bone-tumor niche. Recently, our lab discovered two distinct subpopulations of OBs in the bone-tumor niche based on protein marker expression. One group ‘educated' osteoblasts (EOs) have engaged in crosstalk with disseminated BC cells, whereas another group, ‘uneducated' osteoblasts (UOBs) have not. We have new evidence that EOs suppress osteoclastogenesis and reduce bone resorption associated with BC cell metastatic progression in bone. Culture supernatant of EOs and OBs was analyzed for soluble protein expression of receptor activator of nuclear factor-kappa β ligand (RANKL) and osteoprotegerin (OPG) via ELISA. EOs were co-cultured with pre-osteoclasts to determine OC maturation and resorption. EOs and pre-osteoclasts were co-cultured on a mimetic bone matrix in the presence of soluble RANKL to assess for OC resorption and pit formation. In addition, pre-osteoclasts were tri-cultured with EOs plus either human metastatic triple negative or estrogen receptor positive (ER+) BC cells to assess the effect of BC cells on the formation of OCs. The culture supernatant of EOs expressed reduced amounts of RANKL and OPG soluble protein compared to UOB supernatant. OCs formed in the presence of EOs were approximately half the size of those formed in the presence of UOBs as visualized by TRAP stain. Furthermore, we found up to a 66% reduction in the number of OCs formed in the presence of EOs when compared to the number of OCs formed in the presence of UOBs. When pre-osteoclasts were co-cultured on a mimetic bone matrix, up to 45% reduction was observed in the number of resorptive pits formed upon co-culture with EOs versus UOBs. Moreover, the tri-cultures of pre-osteoclasts, EOs, and human metastatic BC cells yielded up to a 28% reduction in the number of mature, multi-nucleated OCs formed, as opposed to the number of mature, multi-nucleated OCs formed in tri-cultures of pre-osteoclasts, UOBs, plus human metastatic BC cells. Overall, these data suggest that EOs suppress osteoclastogenesis and reduce bone resorption on a bone mimetic surface. These data imply that EOs provide a protective effect against bone resorption during bone metastatic BC progression. These data underscore the importance of investigating EOs as mediators of bone remodeling during BC progression in bone. Supported by NIH R00 CA178177 and Commonwealth of Pennsylvania-Department of Health SAP 4100072566 for KMB.

Citation Format: Alexus D. Kolb, Karen M. Bussard. 'Educated' osteoblasts suppress osteoclastogenesis and bone resorption in a bone mimetic microenvironment [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 3993.