bluuebunny/crossref_metadata_2025 huggingface dataset:
Characterization of Endogenous Auxins and Gibberellins Produced by Chlorella sorokiniana TH01 under Phototrophic and Mixtrophic Cultivation Modes toward Applications in Microalgal Biorefinery and Crop Research
Authors: Do Thi Cam Van , Tran Dang Thuan , Le Truong Giang , Nguyen Quang Trung
Published: June 2020

Microalgae have been reported to produce endogenous phytohormones including auxins, gibberellins, cytokinins, brassinosteroids, and abscisic acid. Methanol residual released from microalgal lipid extraction usually contains a variety of bioactive compounds including the phytohormones; however, they are poorly characterized and used for other applications. This study aimed at investigating auxin, gibberellin, and cytokinin production of C. sorokiniana TH01 under phototrophic and mixtrophic cultivations. Moreover, endogenous auxins, gibberellins, and cytokinins in methanol residual obtained from the algal lipid extraction were characterized using HPLC-ESI-MS/MS toward application for crop and biorefinery research. Data showed that endogenous indole-3-acetic acid (IAA), 3-indolepropionic acid (IPA), gibberellin A4 (GA4), and gibberellin A7 (GA7) were detected in C. sorokiniana TH01 biomass. Under the phototrophic mode, total auxin and GA levels were reduced to 0.98 and 9.65 μg/g DW under salt stress (20 g NaCl/L) from 3.59 to 24.71 μg/g DW, respectively, measured for the control. Similarly, total auxins and GAs were also decreased to 0.56 and 2.86 μg/g DW, respectively, under mixtrophic growth with 6 g glucose/L. Total auxins and GAs determined in the water algal extract were 1062.7 and 2000.1 μg/L, respectively. Treatment with higher 40% (v/v) of the algal extract triggered earlier seed germination of rice and tomato plants in 2 and 1 days, respectively. Our new findings in capability of C. sorokiniana TH01 in endogenous phytohormone production contain fundamental merits for further optimization of the algal production (i.e., cultivation modes, conditions, lipids, biomass productivity, and hormone levels) to be used for biorefinery.
Dynamic Analysis of Metro Train-Monolithic Bed Track System under Tunnel Differential Settlement
Authors: Jiang Jiqing , Dong Beibei , Ding Zhi , Wei Gang , Zhang He , Liao Juan
Published: June 2020

The metro tunnel lines built in a soft soil area may suffer from tunnel differential settlement due to the high compressibility of soft soil, the engineering constructions nearby tunnel lines, and the cyclic load of metro trains. In this paper, a dynamic coupling model for a metro train-monolithic bed track system under tunnel differential settlement is established. A cosine function is introduced to simulate a real settlement curve measured from a metro tunnel in southern China, and the vibration performance of the train-track system under tunnel settlements is investigated in both the time domain and frequency domain. Based on the standards for the train safety and passengers’ comfort, the speed limit for the metro train traveling on a monolithic bed track with different settlement distributions are concluded. The present research could be useful for the operation and maintenance of metro tunnels in soft soil areas.
Network Pharmacology‐Based Identification of the Mechanisms of Shen‐Qi Compound Formula in Treating Diabetes Mellitus
Authors: Hu Zhipeng , Yang Maoyi , Yang Liangjun , Xie Chunguang , Gao Hong , Fu Xiaoxu , Xie Hongyan , Liu Ya
Published: June 2020

Aim. The purpose of this research is to identify the mechanisms of Shen‐Qi compound formula (SQC), a traditional Chinese medicine (TCM), for treating diabetes mellitus (DM) using system pharmacology. Methods. The active components and therapeutic targets were identified, and these targets were analyzed using gene ontology (GO) enrichment analysis, Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis, and protein‐protein interaction (PPI) analysis. Finally, an integrated pathway was constructed to show the mechanisms of SQC. Results. A total of 282 active components and 195 targets were identified through a database search. The component‐target network was constructed, and the key components were screened out according to their degree. Through the GO, PPI, and KEGG analyses, the mechanism network of SQC treating DM was constructed. Conclusions. This study shows that the mechanisms of SQC treating DM are related to various pathways and targets. This study provides a good foundation and basis for further in‐depth verification and clinical application.
Blunt Isolated Small Bowel Perforation Intervention: Does a Delay in Management Matter?
Authors: Hong Sung Yong , Kim Se Hun , Kim Ki Hoon
Published: June 2020

Purpose. Blunt small bowel injury is rare, and its timely diagnosis may be difficult. The effects of a delayed intervention on prognosis are unclear. We aimed to determine whether the time to surgical intervention affects outcomes in patients with blunt small bowel perforation.Methods. The study was performed between March 2010 and December 2018 in adults (age >18 years) who initially underwent computed tomography and small bowel surgery only and survived more than one day postoperatively. They were categorized into three groups based on injury-to-surgery time intervals: ≤8, 8–24, and >24 h; similarly, they were also categorized into two groups of ≤24 and >24 h.Results. Bowel resection, length of stay (LOS), intensive care unit (ICU) LOS, morbidity, and mortality were analyzed as outcomes in 52 patients. The number of patients in the three groups (≤8, 8–24, and >24 h) based on the time-to-surgery was 33, 13, and 6, respectively. On comparing the three groups, there were no significant differences in LOS (24 [18–35], 21 [10–40], and 28 [20–98] days, respectively;p=0.321), ICU LOS (2 [1–12], 4 [2–26], and 11 [7–14] days; respectively,p=0.153), mortality (3% (n = 1), 15% (n = 2), and 0%, respectively;p=0.291), and morbidity (46% (n = 15), 39% (n = 5), and 50% (n = 3), respectively;p=0.871). However, there was a significant difference between the groups in bowel resection (67% (n = 22), 31% (n = 4), and 83% (n = 5), respectively;p=0.037). Additionally, there was no significant difference in outcomes between the two groups (≤24 and >24 h) with small bowel perforation.Conclusions. Delay in surgical intervention following blunt abdominal trauma may not affect the outcomes of patients with small bowel injuries, such as LOS, ICU LOS, morbidity, and mortality, except bowel resection.
Lenvatininb as Treatment for Naïve Patients with Aggressive Thyroid Cancer Bone Metastases and Bad Performance Status
Authors: Garcia-Rodriguez Sonia , Pinillos Guillermo Martinez , Chaves-Conde Manuel
Published: June 2020

Lenvatinib is an oral multityrosine kinase inhibitor (TKI) with proven effectiveness in the treatment of radioactive iodine- (RAI-) refractory and/or unresectable differentiated thyroid carcinoma (DTC). The present study reports the case of a 41-year-old male who underwent hemithyroidectomy in June 2015 due to a thyroid nodule with fine-needle aspiration follicular neoplasm cytology and no evidence of malignancy in the histopathological exam. Three years later, acute disabling clinical symptoms emerged, mainly high skeletal pain conditioned with an important performance status decrease. PET/CT scan displayed several metastatic bone lesions in this context, located in the vertebral bodies, sternum, ribs, iliac crest, right acetabulum, and both necks of the femur. Histological study and immunohistochemistry confirmed DTC metastases, as they were strongly positive for thyroglobulin and TTF-1. At this point, the patient was unfit for conventional management that would have included completion of surgery and RAI treatment as first options. Thus, it was decided to start systemic treatment with TKI, Lenvatinib. Within the first week of treatment, the patient was almost asymptomatic and his performance status moved from 3 to 0. This allowed the patient to undergo resection of the thyroid gland remnant plus RAI treatment. Unfortunately, RAI refractory illness was confirmed so Lenvatinib treatment should be continued in this case until the evidence of no further clinical benefit. Despite drug adverse events, the patient continues with treatment one year later, remaining asymptomatic and with normal functional capacity.
Air Pollution of Nature Reserves near Cities in Russia
Authors: Kholodov Aleksei , Golokhvast Kirill
Published: June 2020

Today, protected natural areas cover about 15% of the Earth’s land. These areas by definition are supposed to be free of pollution; they nevertheless suffer from the effects of aerial transport of anthropogenic polluting substances. In this study, we evaluated the impact of settlements on protected natural areas to determine the optimal distance beyond which the anthropogenic influence would be minimal. For this purpose, we analyzed the particle size distribution and the content of metals in fresh snow samples collected in the Bastak Nature Reserve and the neighboring Birobidzhan city (Russian Federation). Both sites contained comparable proportions of PM10 and contents of heavy metals, which points to the transportation of air pollutants from the city to the reserve. The results of the analysis were summarized and compared with the available data on other nature reserves and nearby populated localities. Based on the research data, pollutant emissions should be decreased for cities that are closer than 50 km to nature reserves. Moreover, authorities should take into consideration atmospheric factors and distance to the nearest settlement when establishing new protected natural areas.
Abstract A05: Nomograms based on the SEER database for predicting the prognosis of pulmonary large-cell neuroendocrine carcinoma: A population-based STROBE cohort study
Authors: Wu Hong-fen
Published: June 2020

Background: This work aimed at the development and validation of nomograms for predicting patient survival cancer-specific survival (CSS) and overall survival (OS) in the context of pulmonary large-cell neuroendocrine carcinoma (LCNEC).

Material and Methods: Based on the SEER database, patients were selected who received diagnosis between the period 2004 and 2014, through the Surveillance, Epidemiology, and End Results (SEER) database. Variables were subjected to univariate and multivariate studies, performed through Cox’s Proportional Hazards Regression model. The 3- and 5-year CSS and OS were predicted based on a nomogram constructed from prognostic factors that were independent. The accuracy of the nomogram was evaluated using discrimination and calibration plots.

Results: From 1,837 eligible patients based on the SEER database, assignment of 1,276 patients was done to the training set, while that of 561 patients was done to the validation set. Multivariate analyses revealed that age, laterality, tumor size, N stage, M stage, surgery, and chemotherapy were significant prognostic factors for CSS, while those of OS were age, laterality, tumor size, surgery, N and M stages, chemotherapy, and radiation. The concordance index (C-index) for CSS was 0.781 (95% CI: 0.766-0.796) and 0.754 (95% CI: 0.730-0.778) for the internal and external validations, respectively. The values for OS were 0.791 (95%CI: 0.776-0.806) and 0.775 (95% CI: 0.751-0.799), respectively. For the training and the validation sets, discrimination in terms of prediction of OS and CSS was better in the nomograms against the SEER summary stage as well as AJCC TNM staging systems (6th edition) (P<0.001). The CSS and OS predicted by the nomograms closely corresponded to actual observation as shown by calibration plots.

Conclusion: Prediction of the 3- and 5-year CSS and OS of patients with pulmonary LCNEC by nomograms with higher accuracy than existing staging models was demonstrated.

Note: This abstract was not presented at the conference.

Citation Format: Hong-fen Wu. Nomograms based on the SEER database for predicting the prognosis of pulmonary large-cell neuroendocrine carcinoma: A population-based STROBE cohort study [abstract]. In: Proceedings of the AACR Special Conference on the Evolving Landscape of Cancer Modeling; 2020 Mar 2-5; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2020;80(11 Suppl):Abstract nr A05.
Abstract A09: Pregnancy reprograms the epigenome of mammary epithelial cells and blocks the development of premalignant mammary lesions in response to cMYC-overexpression
Authors: Feigman Mary J. , Moss Matthew A. , Chen Chen , Cyrill Samantha L. , Ciccone Michael , Trousdell Marygrace , Yang Shih Ting , Frey Wesley D. , Wilkinson John E. , dos Santos Camila O.
Published: June 2020

Pregnancy instates a series of cellular and molecular modifications in the mammary epithelial cells (MECs) of the adult female mammary gland. Pregnancy is also known for decreasing the predisposition of rodent and human MECs to oncogenesis. In order to understand the molecular basis for this protective effect, we analyzed the epigenetic changes in the enhancer landscape of murine, post-pregnancy MECs, and their effect on gene regulation, tissue development, and oncogenesis. Using in vivo and in vitro models of normal and malignant mammary development, we found that completion of a pregnancy cycle changed the dynamics of cellular proliferation and gene expression in response to a second wave of pregnancy hormones. Our results also demonstrated that post-pregnancy MECs are resistant to the molecular programs driven by cMYC overexpression, a response that blocked the development of premalignant lesions but did not perturb the pregnancy-induced epigenomic landscape.

Citation Format: Mary J. Feigman, Matthew A. Moss, Chen Chen, Samantha L. Cyrill, Michael Ciccone, Marygrace Trousdell, Shih Ting Yang, Wesley D. Frey, John E. Wilkinson, Camila O. dos Santos. Pregnancy reprograms the epigenome of mammary epithelial cells and blocks the development of premalignant mammary lesions in response to cMYC-overexpression [abstract]. In: Proceedings of the AACR Special Conference on the Evolving Landscape of Cancer Modeling; 2020 Mar 2-5; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2020;80(11 Suppl):Abstract nr A09.
Abstract A13: ASCL1 confers tolerance to tyrosine kinase inhibitors in EGFR mutant lung cancer
Authors: Hu Bomiao , de Miguel Fernando J. , Liu Zongzhi , Chan Lok-Hei , Melnick Mary Ann , Yan Qin , Nguyen Don , Fan Rong , Politi Katerina
Published: June 2020

The majority of EGFR mutant lung adenocarcinomas respond well to EGFR tyrosine kinase inhibitors (TKIs). However, the majority of these responses are partial, with drug-tolerant residual disease remaining even at the time of maximal response. This residual disease serves as a reservoir for the emergence of acquired resistance and tumor relapse, which inevitably occurs in patients treated with TKIs. It is thus critical to understand the biology of residual tumor cells and find out the mechanisms that underlie drug tolerance. Knowledge of such mechanisms could lead to the identification of potential strategies to forestall the emergence of drug resistance. Studies of residual disease have been hampered by the difficulty of studying these persister cells in patient specimens, and most studies to date have relied on analysis of established cell lines in culture. To investigate the cellular and molecular properties of residual tumor cells in vivo, we leveraged patient-derived models of EGFR mutant lung cancer. Three EGFR mutant PDXs were treated with the 3rd-generation TKI osimertinib. Tumors regressed in all cases, but measurable residual tumor remained in 2 out of the 3 PDXs even after 6 weeks of osimertinib treatment. Whole-exome sequencing (WES) of the untreated PDXs compared to the residual tumors revealed an unchanged mutational landscape between the samples, indicating that genetic mechanisms did not account for drug tolerance. Bulk RNA-sequencing, however, revealed extensive transcriptional changes between the untreated PDX and residual disease. In one of the PDXs, we identified upregulation of neuroendocrine lineage transcription factor ASCL1 in residual disease compared to untreated tumors. Using single-cell RNA-sequencing, we found a pre-existing ASCL1hi tumor cell population in untreated tumors, suggesting that these cells, which possessed drug-tolerant properties, were selected for during drug treatment. Depending on the cell line examined, expression of ASCL1 in human mutant EGFR lung cancer cell lines increased the number of persister clones following osimertinib treatment, indicating that the cellular context contributed to ASCL1’s role in conferring drug tolerance. Our studies provide insights into the role of neuroendocrine factor ASCL1 as a potential driver of drug tolerance in mutant EGFR lung cancer, and ongoing work is focused on identifying the mechanistic underpinnings of these findings.

Citation Format: Bomiao Hu, Fernando J. de Miguel, Zongzhi Liu, Lok-Hei Chan, Mary Ann Melnick, Qin Yan, Don Nguyen, Rong Fan, Katerina Politi. ASCL1 confers tolerance to tyrosine kinase inhibitors in EGFR mutant lung cancer [abstract]. In: Proceedings of the AACR Special Conference on the Evolving Landscape of Cancer Modeling; 2020 Mar 2-5; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2020;80(11 Suppl):Abstract nr A13.
Abstract A16: Patient-derived organoid-based models for endometrial cancer
Authors: Berg Hege F. , Fonnes Tina , Strand Elin , Espedal Heidi , Stefansson Ingunn M. , McCormack Emmet , Bjørge Line , Trovik Jone , Haldorsen Ingfrid S. , Hoyvik Erling A. , Krakstad Camilla
Published: June 2020

Introduction: Comprehensive profiling of tumors using omics technologies has improved our understanding of the molecular landscape of endometrial cancer (EC), building the foundation for precision medicine. However, targeted therapies that show promise in preclinical research are failing clinical trials, which is partly explained by the lack of models that mimic the physiopathology of patients. We aimed at establishing organoids and organoid-based patient-derived xenograft (O-PDX) models as part of a new preclinical platform for endometrial cancer.

Methods: Aggregates of tumor cells were isolated from fresh tumor samples, followed by long-term culturing as organoids in a chemically defined medium. Established organoids were implanted into the left uterine horn of NSG mice, and tumor growth was monitored using near-infrared fluorescence imaging (NIRF). Patient tissue, organoids, and corresponding O-PDXs were characterized by histology and whole-exome sequencing and by immunohistochemical staining of important endometrial cancer biomarkers. For proof of concept, selected models were treated with conventional therapeutic agents, including in vivo treatment with carboplatin.

Results: Organoids and orthotopic O-PDXs representing different subtypes of endometrial cancer were successfully established. Histologic and molecular profiles of organoids are similar to patient tissue, also after long-term culturing, and characteristics of O-PDXs were sustained after rederivation in vivo. Proof-of-concept drug testing shows heterogenous sensitivity to clinically administered chemotherapeutics.

Conclusion: We have extended the collection of EC organoids and established O-PDX models for in vivo studies. This state-of-the-art preclinical platform enables more clinically relevant drug testing that will facilitate translation into relevant clinical trials.

Citation Format: Hege F. Berg, Tina Fonnes, Elin Strand, Heidi Espedal, Ingunn M. Stefansson, Emmet McCormack, Line Bjørge, Jone Trovik, Ingfrid S. Haldorsen, Erling A. Hoyvik, Camilla Krakstad. Patient-derived organoid-based models for endometrial cancer [abstract]. In: Proceedings of the AACR Special Conference on the Evolving Landscape of Cancer Modeling; 2020 Mar 2-5; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2020;80(11 Suppl):Abstract nr A16.
Abstract A17: Polyploid giant cancer cells lead to evolution of drug resistance in high-grade ovarian cancer
Authors: Niu Na , Li Xiaoran , Yao Jun , Sood Anil , Liu Jinsong
Published: June 2020

Whole genomic duplications (WGD) have been reported in 37% to 56% of high-grade cancers. WGD leads to formation of polyploid giant cancer cells (PGCCs) with salient and atypical nuclear morphology noted by light microscopy. However, PGCCs are generally considered nonviable due to their inability to execute mitosis. We have recently reported that PGCCs are capable of generating mitosis-competent progeny cells via primitive amitotic division including budding, splitting, and burst. We have further demonstrated that PGCCs are part of the process of somatic reprogramming named the giant cell life cycle composed of four distinct but overlapping phases including initiation, self-renewal, termination, and stability. The giant cell life cycle resets the somatic cell from the mitotic cycle to stress-induced endoreplication cell cycle via WGD to form PGCCs. The PGCCs activate endogenous embryonic factors for the reprogramming, which leads to the birth of drug-resistant cells by clonal selection from newly generated heterogeneous cancer stem cells. However, the underlying genetic and epigenetic mechanisms during WGD remain unclear. By mapping DNA methylation and whole-genome sequencing, monitoring the telomere dynamics, and tracking the cellular and nuclear morphology using microscopic time-lapse imaging observations during the time course of giant cell life cycle, we hereby provide new evidence that the daughters cells derived from PGCCs have massive alterations at the whole-genome and epigenome levels. The reprogrammed resistant daughter cells are achieved, at least in part, by genomic instability via shortened telomeres. Targeting PGCCs and promoting their differentiation during the course of giant cell life cycle may represent a novel approach to intercept drug resistance.

Citation Format: Na Niu, Xiaoran Li, Jun Yao, Anil Sood, Jinsong Liu. Polyploid giant cancer cells lead to evolution of drug resistance in high-grade ovarian cancer [abstract]. In: Proceedings of the AACR Special Conference on the Evolving Landscape of Cancer Modeling; 2020 Mar 2-5; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2020;80(11 Suppl):Abstract nr A17.
Abstract A27: Heterotypic 3D bioprinted tissues to interrogate tumor-microenvironment crosstalk in cancer
Authors: Langer Ellen M. , English Isabel A. , Turnidge Megan A. , Doha Zinab O. , Sears Rosalie C.
Published: June 2020

The tumor microenvironment is composed of multiple cell types (e.g., fibroblast, vascular, and immune cells), extracellular matrix (ECM) proteins, and signaling molecules that critically influence tumor cell phenotypes. The study of isolated tumor cells in culture has contributed to the discovery of oncogenes and tumor suppressors that regulate oncogenic phenotypes. As tumors develop, however, cancer cells secrete factors that functionally reprogram the genetically “normal” stromal cells in their environment. These tumor-associated stromal cells then further alter the microenvironment, providing tumor-stromal cell and tumor-ECM interactions that critically regulate tumor behaviors such as early tumor initiation, metastatic progression, and response to therapies. We recently developed heterotypic, scaffold-free tissue models of advanced cancer using an extrusion-based bioprinter system. Multiple cell types including cancer cells, fibroblasts, bone marrow-derived mesenchymal stem cells, and endothelial cells can be incorporated into bioprinted tissues with defined architecture. We found that cells within these structures exhibit a tissue-like cellular density, proliferate, deposit ECM, migrate, and respond to extrinsic signals. Cells within these tissues self-organize to form complex structures, as indicated by nascent endothelial networks, and respond to extrinsic signals. We assessed intrinsic, extrinsic, and spatial tumorigenic phenotypes including cell survival, cell proliferation, differentiation state, ECM deposition, and cellular migration within these tissues in response to extrinsic signals or therapies. Together, this work demonstrates that bioprinted tumor tissue models recapitulate many aspects of in vivo neoplastic tissues. We are continuing to use 3D bioprinted tumor tissues, leveraging the manipulable nature of these models to interrogate the role of distinct tumor microenvironments on tumor cell phenotypes including proliferation, migration, and response to therapies. In pancreatic cancer models, we have printed tissues containing pancreatic stellate cells with and without knockdown of the prolyl isomerase PIN1, which we show inhibits stellate cell activation. We show that loss of PIN1 in the stellate cells surrounding the tumor has effects not only on activation markers of fibroblasts, but also on tumor, endothelial, and immune phenotypes within the tissues. Further work is focused on characterizing the signals that drive these changes.

Citation Format: Ellen M. Langer, Isabel A. English, Megan A. Turnidge, Zinab O. Doha, Rosalie C. Sears. Heterotypic 3D bioprinted tissues to interrogate tumor-microenvironment crosstalk in cancer [abstract]. In: Proceedings of the AACR Special Conference on the Evolving Landscape of Cancer Modeling; 2020 Mar 2-5; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2020;80(11 Suppl):Abstract nr A27.
Abstract A29: Dissecting the mechanisms of senescence immune surveillance in liver cancer
Authors: Chen Hsuan-An , Alonso-Curbelo Direna , Ho Yu-Jui , Morris John P. , Houlihan Shauna , Smolkin Ryan , Luan Wei , Hendrickson Ronald C. , Lowe Scott W.
Published: June 2020

Senescence is a cell cycle arrest program that limits the expansion of damaged cells and can trigger antitumor immunity that leads to their elimination in vivo, serving as a potent barrier to tumorigenesis. However, during tumor initiation, the effective clearance of senescent cells is compromised, warranting a deeper mechanistic understanding of this process. To define the critical immunomodulatory factors mediating senescence immune surveillance and how these mechanisms are bypassed during cancer development and progression, we exploited a genetic approach in which liver tumor cells can be triggered to senesce by restoration of tumor suppressor p53. p53 reactivation triggers cytostatic response in vitro, yet it drives robust regression of established liver tumors in immunocompetent mice. Profiling of the immune landscape upon senescence induction revealed that there is an accumulation of CD8 and CD4 T cells in the tumor microenvironment. Consistently, immune cell blockade through depleting antibodies blunts tumor regression, indicating a key role of adaptive immunity in this process. To gain mechanistic insight into how senescent cells are recognized by the immune system, RNA-seq and mass spectrometry were conducted on both proliferating and senescent tumor cells and revealed several senescence-enriched cell surface factors related to epithelial-immune cell interactions and MHC-I presentation. Ongoing work aims to functionally interrogate the role of these senescence-induced factors as novel senescence surveillance effectors. Our research will increase the current knowledge of the strategies to trigger senescence in advanced cancers that can restore immune surveillance programs lost during the course of tumor evolution.

Citation Format: Hsuan-An Chen, Direna Alonso-Curbelo, Yu-Jui Ho, John P. Morris IV, Shauna Houlihan, Ryan Smolkin, Wei Luan, Ronald C. Hendrickson, Scott W. Lowe. Dissecting the mechanisms of senescence immune surveillance in liver cancer [abstract]. In: Proceedings of the AACR Special Conference on the Evolving Landscape of Cancer Modeling; 2020 Mar 2-5; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2020;80(11 Suppl):Abstract nr A29.
Abstract A36: Organoid models for deciphering roles of the evolving landscape of epigenetic heterogeneity during aging in cancer development
Authors: Tao Yong , Kang Byunghak , Petkovich Daniel , Baylin Steve , Easwaran Hariharan
Published: June 2020

Background: Tumor initiation and development occur not necessarily by genetic changes alone, but in the context of the epigenome and cell microenvironment. Growing evidence indicate that cancer risk factors, such as aging and inflammation, may primarily modulate the epigenome, causing predisposition to cancer development by driver mutations. Thus, there is a need to study and model epigenetic changes preceding and associating with cancer development. We have developed ex vivo models for investigating the evolution and roles of DNA methylation changes during normal cell divisions and how these epigenetic changes play critical roles in early stages of tumor development.

Results: We showed that spontaneous epigenetic changes, specifically promoter-DNA hypermethylation, have a very important role in tumor initiation by oncogenic driver mutations. We addressed the precursor role of aging-like spontaneous promoter-DNA hypermethylation in initiating tumorigenesis. Using mouse colon-derived organoids, we show promoter hypermethylation spontaneously arises in cells mimicking the human “aging-like” phenotype. The silenced genes activate the Wnt pathway, causing a stemlike state and differentiation defects. These changes render aged organoids profoundly more sensitive than young ones to transformation by BrafV600E producing the typical human proximal BRAFV600E-driven colon adenocarcinomas characterized by extensive, abnormal gene promoter CGI methylation or the methylator phenotype (CIMP). Conversely, CRISPR-mediated simultaneous inactivation of a panel of the silenced genes markedly sensitized to BrafV600E-induced transformation. We showed that “spontaneous” promoter hypermethylation, arising in an “aging-like” scenario, sufficiently affects genes with roles in negative regulation of Wnt pathway. Inactivation of these genes leads to increased stem cell state and defects in differentiation.

Conclusion: Our studies tightly link aging-like epigenetic abnormalities to intestinal cell fate changes and predisposition to oncogene-driven colon tumorigenesis. The organoid-based model opens up an opportunity to study mechanisms underlying epigenetic heterogeneity arising during normal cellular processes and their role in cancer predisposition.

Citation Format: Yong Tao, Byunghak Kang, Daniel Petkovich, Steve Baylin, Hariharan Easwaran. Organoid models for deciphering roles of the evolving landscape of epigenetic heterogeneity during aging in cancer development [abstract]. In: Proceedings of the AACR Special Conference on the Evolving Landscape of Cancer Modeling; 2020 Mar 2-5; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2020;80(11 Suppl):Abstract nr A36.
Abstract A38: A critical role of Wnt5a-Axin2 axis in small-cell lung cancer development
Authors: Kim Kee-Beom , Kim Dong-Wook , Kim Youngchul , Park Jae-Il , Park Kwon-Sik
Published: June 2020

The paucity of readily actionable alterations in the small-cell lung cancer (SCLC) genome necessitates exploration of alternative targets for clinical intervention, including reactivated developmental signaling pathways. Despite the widespread implication of deregulated WNT signaling in cancer, its role in the pathogenesis of SCLC remains unknown. In this study, we observe selective induction of Axin2, a target of WNT pathway, and its genetic reporter in the lung tumors developed in genetically engineered mouse models (GEMM) of SCLC. Intriguingly, however, other transcription targets of b-catenin-dependent “canonical” pathway are downregulated in tumors relative to normal lung, and knockout of Ctnnb1 encoding b-catenin does not affect tumor development in the GEMM. On the other hand, Axin2 knockout, which enhances b-catenin level, suppresses the tumor development. These findings suggest not only the dispensability of b-catenin-dependent pathway but also the significant role of Axin2 in SCLC. Meanwhile, we observe that tumors and cell lines express significantly higher levels of ligands for b-catenin-independent “noncanonical” pathway, including Wnt5a, than precancerous cells (preSC) as well as whole lung. Ectopic Wnt5a in preSC enhances cell proliferation in culture and tumorigenic capacity in athymic nude mice while increasing Axin2 expression. Depletion of Wnt5a suppresses cell proliferation and tumor development. Taken together, these results suggest a critical role of the Wnt5a-Axin2 axis in SCLC development.

Citation Format: Kee-Beom Kim, Dong-Wook Kim, Youngchul Kim, Jae-Il Park, Kwon-Sik Park. A critical role of Wnt5a-Axin2 axis in small-cell lung cancer development [abstract]. In: Proceedings of the AACR Special Conference on the Evolving Landscape of Cancer Modeling; 2020 Mar 2-5; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2020;80(11 Suppl):Abstract nr A38.
Abstract B08: High-resolution positron emission microscopy of patient-derived tumor organoids
Authors: Khan Syamantak , Shin June Ho , Cheng Ning , Kuo Calvin , Sunwoo John , Pratx Guillem
Published: June 2020

Tumor organoids are self-organizing three-dimensional tumor models grown in vitro from patient-derived tumor tissue. They closely recapitulate the structural and functional microenvironment of solid tumors. Rapid translation of biomedical information from preclinical models to patients requires imaging biomarkers that span the full scale of tumor models. However, a key limitation is that, unlike human patients or preclinical mouse models, the tiny organoids are incompatible with the suite of radiologic tools used in oncology clinics. Here, we present 18F-fluorodeoxyglucose positron-emission microscopy (FDG-PEM), a radioluminescence-based technique for imaging glucose metabolism in patient-derived tumor organoids with spatial resolution 100-fold better than that of clinical positron emission tomography (PET). Tumor organoids derived from head-and-neck cancer patients were imaged to reveal metabolic maps that, in combination with brightfield imaging, functionally mirror the PET/CT images from the clinic. Tumor organoids were fed with FDG and mounted on a thin CdWO4 scintillator plate. Scintillator flashes were directly imaged by a single-photon-sensitivity electron-multiplying charge-coupled devices (EMCCD) camera. The EMCCD signal was calibrated with known radioactivity of FDG for accurate quantification of PEM images. Dual-modality PEM/fluorescence imaging found that FDG uptake occurred mainly in the viable region of tumor organoids and was more specific than staining by 2-NBDG, a fluorescent glucose mimetic. The influx rate constant (Ki) of FDG into the tumor organoids was calculated and found to be similar to the patient tumor from which the organoids were grown. This positive correlation of FDG influx between patient and organoid tumor suggests that PEM can be a preclinical tool to bridge the gap between laboratory and clinical cancer imaging. Finally, organoids treated with cisplatin displayed a dose-dependent decrease in the metabolic activity, while organoids derived from cisplatin-resistant patients retained high metabolic activity despite cisplatin treatment. Our results suggest that PEM imaging of patient-derived organoids could be used to predict individual patient response to different treatments to provide a more personalized approach to cancer care.

Citation Format: Syamantak Khan, June Ho Shin, Ning Cheng, Calvin Kuo, John Sunwoo, Guillem Pratx. High-resolution positron emission microscopy of patient-derived tumor organoids [abstract]. In: Proceedings of the AACR Special Conference on the Evolving Landscape of Cancer Modeling; 2020 Mar 2-5; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2020;80(11 Suppl):Abstract nr B08.
Abstract B13: A novel mouse model for small-cell carcinoma of bladder
Authors: Xu Dongbo , Cao Qiang , Wang Li , Wang Yanqing , Zhang Xiaojing , Wu Yue , Smith Gary , Xu Bo , Goodrich David , Li Qiang
Published: June 2020

Background: Molecular characterization studies suggest the neuronal subtype muscle invasive bladder cancer (MIBC) is associated with a high response rate to immune checkpoint inhibitor. We sought to establish a mouse model for small-cell carcinoma of bladder.

Materials and Methods: Three canonical signaling pathways (TP53, RB1, and RTK/PI3K/AKT) are commonly altered in small-cell bladder cancer. Keratin 5 promoter-driven adenovirus Cre (Ad-K5-Cre, University of Iowa) was instilled into the bladder of female triple floxed (Trp53f/f:Pten f/f:Rb1 f/f) mice for 30 min. The mice were monitored for hematuria and bladder mass using ultrasound.

Results: One Ad-K5-Cre:Trp53-/-: Pten-/-: Rb1-/- mouse died from urinary obstruction at 22 weeks. An obstructive tumor was noted in bladder trigone. Immunohistochemistry analysis of bladder tumor demonstrated negative cytokeratin 7 (CK7) expression and strong synaptophysin expression. Disseminated metastatic foci in lung were noted with positive synaptophysin expression as of primary tumor in the bladder. PCR demonstrated Cre mediated recombined alleles of the Trp53, Pten, and Rb1 in the tumor DNA but not in the tail DNA. The bladder tumor was dissociated to generate an organoid line. The organoid after 5 passages was tested for drug response of standard chemotherapy regimens. IC50 of cisplatin, etoposide, and gemcitabine were 3.1 μM, 0.8 μM, and 92.3 nM, respectively. Further characterization of more mice will address the limitation of small sample size.

Conclusion: Inactivation of Trp53, Pten, and Rb1 is sufficient to induce metastatic small-cell carcinoma of bladder. This mouse model provides a powerful tool to study molecular mechanism of neuroendocrine differentiation and screen novel therapeutic drugs for small-cell carcinoma of bladder.

Citation Format: Dongbo Xu, Qiang Cao, Li Wang, Yanqing Wang, Xiaojing Zhang, Yue Wu, Gary Smith, Bo Xu, David Goodrich, Qiang Li. A novel mouse model for small-cell carcinoma of bladder [abstract]. In: Proceedings of the AACR Special Conference on the Evolving Landscape of Cancer Modeling; 2020 Mar 2-5; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2020;80(11 Suppl):Abstract nr B13.
Abstract B38: Impact of nongenetic intratumor heterogeneity on phenotypic characteristics and ongoing evolutionary dynamics in lung tumors
Authors: Sharma Anchal , Merritt Elise , Hu Xiaoju , Cruz Angelique , Malhotra Jyoti , Riedlinger Greogory , De Subhajyoti
Published: June 2020

Impacts of genetic and nongenetic intratumor heterogeneity (ITH) on tumor phenotypes and evolvability remain debated. We analyzed ITH in lung squamous cell carcinoma at the levels of genome, transcriptome, tumor-immune interactions, and histopathologic characteristics by multiregion bulk and single-cell sequencing. Genomic heterogeneity alone was a weak indicator of intratumor nongenetic heterogeneity at immune and transcriptomic levels that impacted multiple cancer-related pathways, including those related to proliferation and inflammation, which in turn contributed to intratumor regional differences in histopathology and subtype classification. Tumor subclones had substantial differences in proliferation score, suggestive of non-neutral clonal dynamics. Proliferation and other cancer-related pathways also showed intratumor regional differences, sometimes even within the same subclones. Neoepitope burden negatively correlated with immune infiltration, indicating immune-mediated purifying selection on somatic mutations. Taken together, our observations suggest that nongenetic heterogeneity is a major determinant of heterogeneity in histopathologic characteristics and impacts evolutionary dynamics in lung cancer.

Note: This abstract was not presented at the conference.

Citation Format: Anchal Sharma, Elise Merritt, Xiaoju Hu, Angelique Cruz, Jyoti Malhotra, Greogory Riedlinger, Subhajyoti De. Impact of nongenetic intratumor heterogeneity on phenotypic characteristics and ongoing evolutionary dynamics in lung tumors [abstract]. In: Proceedings of the AACR Special Conference on the Evolving Landscape of Cancer Modeling; 2020 Mar 2-5; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2020;80(11 Suppl):Abstract nr B38.
Abstract B48: STAT3 pathway in fibroblasts aggravates invasiveness of lung cancer cells in the tumor microenvironment
Authors: Kang Ju-Hee , Lee Ha Jung , Jung Hyun Jin , Kim Min Woo , Oh Seung Hyun
Published: June 2020

Cancer-associated fibroblasts (CAF), as one of the major components of tumor microenvironment, have a significant role in cancer development and progression. CAF also supports the survival and chemo-induced resistance of cancer cells. Among various signaling pathways involved in cancer cell and CAF interaction, the signal transducers and activators of transcription (STAT3) pathway has been investigated a lot, but its own role in CAF itself is not yet clearly defined. In this paper, we established CAF using MRC5, which is a stable lung fibroblast cell line, by culturing with conditioned medium from lung cancer cells. Then, by using a STAT3 inhibitor, STX-0119, and STAT3 siRNA, we examined whether the blocking of STAT3 pathway in MRC5 affects chemotherapeutic resistance or invasiveness of A549 lung cancer cells. We found out that STAT3 inhibition in fibroblasts did not prevent CAF-induced resistance of A549 cells on proliferation, but it did attenuate the invasiveness and migration of A549 cells. These results suggest that the combination of a low dose of a STAT3 inhibitor, which would be high enough to inactivate the CAF around the tumor cells, and an anticancer drug can be taken as an approach to cancer treatment.

Citation Format: Ju-Hee Kang, Ha Jung Lee, Hyun Jin Jung, Min Woo Kim, Seung Hyun Oh. STAT3 pathway in fibroblasts aggravates invasiveness of lung cancer cells in the tumor microenvironment [abstract]. In: Proceedings of the AACR Special Conference on the Evolving Landscape of Cancer Modeling; 2020 Mar 2-5; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2020;80(11 Suppl):Abstract nr B48.
Abstract IA05: Signaling networks in small-cell lung cancer
Authors: Sage Julien
Published: June 2020

SCLC is a lethal neuroendocrine (NE) cancer that accounts for ~15% of all lung cancers and causes ~250,000 deaths worldwide each year. SCLC is linked to heavy cigarette smoking and exposure to carcinogens. Unfortunately, the number of SCLC-related deaths continues to rise. A major clinical challenge is that ~70% of SCLC patients have disseminated disease at the time of diagnosis; these patients have a 5-year survival of <1%. Even patients with localized disease at diagnosis have dismal survival rates. A second major challenge is that treatments for SCLC are inefficient and have remained mostly unchanged for the past 30 years, with no new approved treatments since 1996 and no approved targeted therapies. SCLC is managed with first-line chemoradiation. Patients usually respond well initially, but almost all relapse within months. There is a need to better understand the mechanisms underlying the aggressive growth and spread of SCLC and its rapid chemoresistance. At a gross level, SCLC tumors are quite “homogeneous” histologically (with fields of similar-looking small, blue, round cancer cells) and genetically (with near-ubiquitous loss of the Rb and p53 tumor suppressors). However, accumulating evidence has recently highlighted several levels of heterogeneity, and it has become clear that a better characterization and understanding of both genetic and epigenetic heterogeneity during SCLC progression will be critical to identify new therapeutic options. We have used mouse genetics combined with genomic and proteomic approaches to identify key signaling pathways that are implicated in the expansion of SCLC cell populations. In particular, we have recently identified kinases and phosphatases that control the expansion of long-term propagating cells (aka cancer stem cells) in SCLC.

Citation Format: Julien Sage. Signaling networks in small-cell lung cancer [abstract]. In: Proceedings of the AACR Special Conference on the Evolving Landscape of Cancer Modeling; 2020 Mar 2-5; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2020;80(11 Suppl):Abstract nr IA05.
Abstract IA08: Organoid modeling of tumor and tissue microenvironments
Authors: Kuo Calvin J.
Published: June 2020

Within the tumor microenvironment are diverse populations including fibroblasts, vasculature, and immune cells, all of which critically regulate cancer progression. A major historical impediment to basic and translational cancer studies has been the lack of in vitro methods that allow tumor epithelium to be robustly cultured together with stromal components. This talk will describe advances in 3D tumor organoid culture that allow tumor cells to be grown in a manner that preserves their native interaction with diverse tumor-infiltrating immune cells and allows analysis of immune checkpoint inhibition. Such organoid modeling of the tumor immune microenvironment within human clinical cancer biopsies will facilitate basic and translational immune-oncology studies. Additional applications to nonmalignant diseases will also be discussed.

Citation Format: Calvin J. Kuo. Organoid modeling of tumor and tissue microenvironments [abstract]. In: Proceedings of the AACR Special Conference on the Evolving Landscape of Cancer Modeling; 2020 Mar 2-5; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2020;80(11 Suppl):Abstract nr IA08.
Abstract IA11: The use of GEM tumor models to identify effective therapies against KRAS mutant tumors
Authors: Barbacid Mariano
Published: June 2020

KRAS oncogenes are responsible for one fourth of all human tumors, including lung and pancreatic adenocarcinomas, two tumor types with some of the worse prognoses. Unfortunately, development of suitable therapies to treat these tumors has remained elusive for the last 35 years. Although KRAS remains an undruggable target (with the possible exception of the KRASG12C isoform), most of its downstream effectors are druggable kinases. Indeed, pharma and biotech companies have already developed dozens of selective inhibitors against these kinases. Yet none of them has been approved by the FDA, mostly due to unacceptable toxicities at antitumor effective doses. Hence, patients are still treated with old chemotherapy drugs. To address this important health issue, we have used a new generation of genetically engineered mouse (GEM) tumor models of KRas/Tp53 driven lung and pancreatic tumors to deconstruct oncogenic KRas signaling to identify those effectors whose systemic ablation/inactivation in tumor-bearing mice will result in therapeutic responses without inducing unacceptable toxicities. We have used this experimental strategy to interrogate the effect of ablating/inactivating each of the members of the MAPK cascade, including the Raf, Mek, and Erk kinases, as well as key effectors of the PI3K pathway, including PI3K p110alpha and mTOR. We have also evaluated additional downstream signaling elements such as the cell cycle Cdks. This systematic approach has revealed that most of the KRas signaling effectors are not suitable therapeutic targets due to either lack of therapeutic activity, such as Cdk2, Cdk6 A-Raf, or B-Raf, or to the induction of unacceptable toxicities such as the Mek1/2 and Erk1/2 kinases, PI3K p110alpha, mTOR, and Cdk1. Only Raf1 and Cdk4 turned out to be suitable therapeutic targets, based not only on their antitumor properties but also on the well-tolerated toxicities. Surprisingly, EGFR, an upstream effect of KRas, also has suitable therapeutic activity in pancreatic but not in lung tumors. We are now combining these targets to define more efficacious therapeutic strategies that could be eventually translated to the clinic. Moreover, we are using these experimental GEM tumor models to identify potential resistance mechanisms to these therapies.

Citation Format: Mariano Barbacid. The use of GEM tumor models to identify effective therapies against KRAS mutant tumors [abstract]. In: Proceedings of the AACR Special Conference on the Evolving Landscape of Cancer Modeling; 2020 Mar 2-5; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2020;80(11 Suppl):Abstract nr IA11.