bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract 5866: SCAR (Selective CRISPR Antigen Removal) vector system expands cancer immunology discovery with in vivo functional genomics
Authors: Dubrot Juan , Lane-Reticker Sarah Kate , Kessler Emily , Wolfe Clara , Mahapatra Animesh , Du Peter , Manguso Robert T. 
Published: September 2020

Abstract
The ability to make rapid genetic alterations to tumor cells with CRISPR for screens and single-gene studies has been transformative for studying cancer biology. Recently, we and others have used CRISPR in murine tumor models in vivo to identify targets and resistance mechanisms for immunotherapy. However, the use of these techniques in immunocompetent mice is limited by endogenous immune recognition of CRISPR components such as Cas9. Here we report the design of a screening-compatible lentiviral vector system which allows selective CRISPR antigen removal (SCAR) from tumor cells before they are implanted in vivo. The SCAR system enables highly efficient genome engineering and reverses CD8+ T cell-mediated rejection of CRISPR modified tumor cells in vivo. Using this technology, we conducted a pooled, in vivo screen designed to probe tumor-immune interactions in the highly immunogenic CT26 colon carcinoma model and discovered that these tumors require intact interferon signaling to evade immune destruction. The SCAR system enables the study of tumor-immune interactions in any cancer model and can be more broadly applied to generate non-immunogenic lentivirally-engineered cells.
Citation Format: Juan Dubrot, Sarah Kate Lane-Reticker, Emily Kessler, Clara Wolfe, Animesh Mahapatra, Peter Du, Robert T. Manguso. SCAR (Selective CRISPR Antigen Removal) vector system expands cancer immunology discovery with in vivo functional genomics [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 5866.
Abstract 5882: Genomic correlates of differential response to EGFR-directed tyrosine kinase inhibitors
Authors: Vokes Natalie , Nguyen Tom , Lydon Christine , Chambers Emily , Sholl Lynette , Nishino Mizuki , Van Allen Eliezer , Janne Pasi 
Published: September 2020

Abstract
Background: Oncogenic mutations in EGFR are powerful biomarkers of response to EGFR tyrosine kinase inhibitors (TKIs) in non-small cell lung cancer (NSCLC). However, there remains significant heterogeneity in duration of response to therapy and overall survival. TP53 mutations have been linked with worse outcomes, thought to be due to increased likelihood of small cell transformation.
Methods: We identified NSCLC patients at our institution with sensitizing oncogenic EGFR mutations who had been treated with EGFR TKI(s) and who had at least one tumor specimen profiled via targeted next generation sequencing (OncoPanel). Progression free survival (PFS) on first-line EGFR TKI, overall survival (OS), and resistance mechanism were assessed. Patients were defined as TP53 mutant positive (TP53+) or wild type (TP53-). Pathogenic TP53 mutations were identified and associated with outcome and resistance mechanism.
Results: We identified 270 patients for inclusion in our cohort. 70% were female (190/270), 60% were never smokers (163/270), and median age was 62 (range 29-93). Sensitizing EGFR mutations were predominantly exon 19 deletion (51%, 138/270) or L858R (38%, 103/270). 94% of patients were treated with first-line erlotinib (253/270), and 30% received second-line osimertinib (82/270). TP53+ patients were as likely to achieve objective radiographic response as TP53- (p=0.615), but had shorter PFS (HR 1.56, CI 1.1-2.2, p=0.011). TP53+ patients were no more likely to develop SCLC transformation (p=0.637). Among patients with T790M as their resistance mechanism, TP53+ patients still had shorter PFS compared to TP53- (HR 1.9, CI 1.2-3, p=0.003). Pre-treatment TP53 mutations were associated with a higher tumor mutational burden (p=0.017) and copy number burden (p=0.0026).
Conclusion: While TP53 mutations associate with shorter PFS, there is no association with baseline TP53 mutation status and small cell transformation, and TP53+ patients also develop the T790M resistance mutation earlier than TP53- patients. Higher mutation and copy number burden in TP53+ patients suggests greater genomic instability and may act as a mechanism of earlier resistance development.
Citation Format: Natalie Vokes, Tom Nguyen, Christine Lydon, Emily Chambers, Lynette Sholl, Mizuki Nishino, Eliezer Van Allen, Pasi Janne. Genomic correlates of differential response to EGFR-directed tyrosine kinase inhibitors [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 5882.
Abstract 5918: The role of the cell-adhesion molecule Metadherin in inflammatory breast cancer progression
Authors: Ortiz-Soto Gabriela , Suárez-Arroyo Ivette J. , Martínez-Montemayor Michelle M. 
Published: September 2020

Abstract
Inflammatory breast cancer (IBC) is the most lethal form of breast cancer where patients display a lower 5-year survival rate. The lethality of IBC originates from its nature of invading the vascular and lymphatic systems, absence of a tumor mass, and generation of tumor emboli. Currently, the accurate and early diagnosis and the development of effective targeted therapies remains a challenge. Thus, in an attempt to discover potential biomarkers, we characterized the IBC cell surface proteome. Plasma membrane proteins were identified via SILAC and MS quantitative proteomics using the IBC SUM-149 vs. MCF-10A a non-cancerous mammary epithelial cell line. SILAC results showed overexpression of Metadherin (MTDH) in IBC cells (&gt;2.0 FCh) and was validated in IBC tissues and emboli. MTDH is a cell adhesion molecule overexpressed in many cancer types, including breast cancer. MTDH promotes cancer progression by modulating various signaling pathways including NF-kB, which is related to cell survival, proliferation, invasion and metastasis. Thus, the aim of this study is to assess the functional role of MTDH in IBC progression. To elucidate the mechanism of action of MTDH in colony formation and tumor spheroids we silenced MTDH (CRISPR or shRNA) SUM-149 and SUM-190 IBC cells. We assessed the expression of MTDH by immunoblotting and immunofluorescence where we observed reduced MDTH levels. The number of colonies formed in SUM-149 MTDH silenced cells was ~40% lower when compared to non-silenced cells. Tumor spheroids of SUM-149 and SUM-190 MTDH silenced cells were smaller than non-silenced cells. Additionally, MTDH silencing results in a decrease in the phosphorylation of the p65 subunit of NF-kB while no changes are observed in total protein abundance in SUM-149 cells. We can conclude from our preliminary results that MTDH serves as a potential IBC target for IBC progression. This work was supported by NIH NIGMS #GM111171 (MMM), SGRP 2017-00143 (MMM and GOS), NIMHD #MD007583 (MMM), GM103475 (UPR MMM), Title-V-PPOHA #P031M105050, Title-V-Cooperative #P031S130068 from the U.S. Dept. of Education and Institutional Development Award (IDeA) from the National Institute of General Medical Sciences of the National Institutes of Health #P20GM103475 (GOS).
Citation Format: Gabriela Ortiz-Soto, Ivette J. Suárez-Arroyo, Michelle M. Martínez-Montemayor. The role of the cell-adhesion molecule Metadherin in inflammatory breast 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 5918.
Abstract 5949: Artesunate influences the transcripts for Eph receptors and ephrin ligands in breast cancer cells
Authors: Zadeh Tanin , Lucero Mariana , Kandpal Raj 
Published: September 2020

Abstract
Purpose: Artesunate (ART), an anti-malarial drug, has been shown to induce apoptosis in breast cancer cells. The current study was conducted to explore the involvement of Eph receptor and ephrin ligand transcript levels in mediating apoptotic functions of ART in three phenotypically distinct breast cell lines. The specific involvement Eph receptors and ephrin ligands in apoptosis may potentially lead to novel approaches for therapeutic intervention of breast cancer.
Methods: We cultured three cell lines that represent non-tumorigenic breast epithelium (MCF10A), non-invasive breast carcinoma (MCF7), and invasive triple negative breast carcinoma (MDA- MB-231) in the presence of varying concentrations of ART. Total RNA was isolated from untreated and ART-treated cell lines, and the relative abundance of Eph receptor and ephrin ligand transcripts was determined by qPCR. The changes in selected transcripts were confirmed by immunocytochemistry and western blot analysis.
Results: Our study revealed that the transcripts corresponding to various Eph receptors and ephrin ligands are differentially expressed in a cell line specific manner in ART-treated cells. Specifically, EphA5 was upregulated and EphB4 was significantly downregulated in MCF10A cells. However, MDA-MB-231 cells were distinguished by upregulation of ephrinA2 and downregulation of EphA7, respectively. MCF7 also showed distinct response to ART treatment. Combinatorial alterations in transcript abundance for a subset of Eph receptors and ephrin ligands are likely to provide meaningful insights in the apoptotic effects of ART in breast cancer cells.
Conclusions: A variety of experiments directly or indirectly support the role of Eph receptors and ephrin ligands in apoptosis of numerous cell types. To our knowledge, there have been no conclusive studies to implicate these molecules in ART-mediated cell death. We have demonstrated cell line-specific alterations in the levels of Eph/ephrin transcripts in cells primed for apoptosis by ART-treatment. Specifically, EphA5, EphA7, EphB4 and ephrin A2 appear to transduce apoptotic signals in ART-treated cells. These observations set the basis for pursuing additional mechanistic investigations to decipher novel mediators of apoptosis in breast cancer cells.
Citation Format: Tanin Zadeh, Mariana Lucero, Raj Kandpal. Artesunate influences the transcripts for Eph receptors and ephrin ligands in breast cancer cells [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 5949.
Abstract 5953: Regulation of androgen receptor stability by nuclear export protein CRM1
Authors: Thomas Naiju , Kumar Rajendra , Topiwala Deven , Boyapati Kavya , Kanacharoen Suthicha , Carducci Michael , Denmeade Samuel , Kachhap Sushant K. 
Published: September 2020

Abstract
Import of ligand-bound androgen receptor (AR) into the nucleus occurs with the help of nuclear importin. Past studies have identified a nuclear export signal (NES) in AR. CRM1 (also called XPO1 or Exportin1) is a well-studied exportin that exports proteins and RNA from the nucleus to the cytoplasm. GTP-bound active Ran, CRM1, and the cargo protein form a ternary complex that is exported through the nuclear pore complex. Previous experimental data indicate that RanGTP plays a vital role in Prostate cancer (PCa) progression. Our analyses further suggest that patients who have overexpression of CRM1 and/or Ran have significantly decreased survival. These results indicate that nucleocytoplasmic transport is essential for prostate cancer progression and inhibiting CRM1 could selectively inhibit cancer cell growth. We demonstrate that CRM1 does not affect the nuclear export of AR protein. However, quite surprisingly, we provide novel evidence that CRM1 binds to AR mRNA and is also required for AR protein stability. Inhibiting CRM1 using CRM1 inhibitor results in a dose-dependent rapid loss of AR and AR-V7 splice variants in PCa cells. This observation opens up an entirely new avenue to therapeutically regulate AR signaling using CRM1 inhibitors.
Citation Format: Naiju Thomas, Rajendra Kumar, Deven Topiwala, Kavya Boyapati, Suthicha Kanacharoen, Michael Carducci, Samuel Denmeade, Sushant K. Kachhap. Regulation of androgen receptor stability by nuclear export protein CRM1 [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 5953.
Abstract 5963: NGS-based murine pan-cancer gene expression panel for immuno-oncology and tumor microenvironment studies
Authors: Chen Xiaobo , Xue Jia , Li Qixiang , Guo Sheng 
Published: September 2020

Abstract
INTRODUCTION: Cancer is a heterogeneous disease and highly related to the immunological system. The significance of fully understanding the interactions between cancer and immunity in cancer therapeutics has been broadly noted, particularly for immunotherapies. Experimental murine models derived from a variety of biological technologies are essential preclinical model systems utilized before clinical studies. Molecular pathology techniques, such as gene expression biomarkers, are widely used to systematically profile and characterize these models. So far, however, there has been no robust and cost-effective assay designed for murine clinical immuno-oncology (I/O) research to characterize tumor-immune interactions at a gene expression level.
METHODS: Marker genes were identified by combining public and in-house reference genomic data for non-tumor bearing mice as well as tumor mouse models. Oligonucleotide-based hybridization/capture techniques analogous to exome sequencing, targeting specific regions are well established on Illumina Novaseq and BGI MGIseq platforms. These methods were applied to the murine I/O panel assay, with accuracy and reproducibility verified across these two sequencing platforms. The results were further qualified using a PCR array platform.
RESULTS: A mouse gene panel involving 1080 genes that encompass surface markers and transcriptomic biomarkers for the immune system, key pathways at the interface of the tumor, tumor microenvironment (TME), and immune response, as well as internal reference genes for data normalization has been established. By combining advanced NGS technologies and specific bioinformatic pipelines, we were able to detect and distinguish various immune and stromal cells involved in the complex interaction between the tumor and its microenvironment, allowing for a multifaceted characterization of disease biology and the interrogation of immune response and evasion. We validated the sensitivity, specificity, and repeatability of the panel by qPCR experiments.
CONCLUSIONS: We have established a murine-I/O NGS panel involving 1080 genes to characterize tumor-immune interactions more efficiently and in a cost-effective manner for preclinical studies. This provides an enhanced insight into the TME, with high-content data that has the potential to translate more effectively to the clinic as well as for early identification of immunotherapy companion diagnostics.
Citation Format: Xiaobo Chen, Jia Xue, Qixiang Li, Sheng Guo. NGS-based murine pan-cancer gene expression panel for immuno-oncology and tumor microenvironment studies [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 5963.
Abstract 5977: Maf1 suppresses hepatocarcinogenesis in mice through inhibition of Akt-mTOR signaling
Authors: Cao Di , Li Xiaoxing , Yang Yang , Zhou Yu-Feng , Zhang Mei-Yin , Zhang Shan-Shan , Ren Qian-Nan , Zhang Hui-Zhong , Zhang Yao-Jun , Mai Shi-Juan , Wang Hui-Yun 
Published: September 2020

Abstract
Maf1 is a transcriptional repressor downstream of mTORC1by inhibiting transcription of lipogenic genes by RNA Pol II and ribosomal/transfer RNA genes by RNA Pol III. We recently showed that Maf1 suppresses the growth of cultured liver cancer cells and xenograft tumors by blocking Akt-mTOR signaling through the tumor suppressor PTEN. However, whether Maf1 has tumor suppressor activity has never been demonstrated in physiologically relevant tumor models. Here, we investigated the role of Maf1 in hepatocarcinogenesis in NRas/Akt- and c-Myc-driven mouse liver cancer models generated by hydrodynamic transfection (HDT). We found that Maf1 or Maf1-4A, a non-phosphorylatable and active form of Maf1, significantly attenuated the development of NRas/Akt-driven liver tumors. On the other hand, while knockdown of Maf1 alone did not cause any discernible abnormality in the mouse liver, down-regulation of Maf1 markedly accelerated c-Myc-induced liver tumor development. At the molecular level, Maf1 strongly suppressed phosphorylation of Akt-mTOR pathway components, including Akt and S6. Conclusions: Maf1 suppresses hepatocarcinogenesis through restraining Akt/mTOR signaling. These new findings provide first in vivo evidence that Maf1 is a liver tumor suppressor.
Citation Format: Di Cao, Xiaoxing Li, Yang Yang, Yu-Feng Zhou, Mei-Yin Zhang, Shan-Shan Zhang, Qian-Nan Ren, Hui-Zhong Zhang, Yao-Jun Zhang, Shi-Juan Mai, Hui-Yun Wang. Maf1 suppresses hepatocarcinogenesis in mice through inhibition of Akt-mTOR signaling [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 5977.
Abstract 5991: Glucose metabolic reprogramming in HBV-related hepatocellular carcinoma through C-terminal truncated HBx protein suppression of TXNIP
Authors: Zhang Yu 
Published: September 2020

Abstract
Hepatitis B virus (HBV) infection has been proven strongly associated with the initiation and progression of hepatocellular carcinoma (HCC). However, a substantial amount of virally-induced mechanisms that cause malignant transformation in the liver remains largely unexplored, especially for HBV-induced metabolic reprogramming. In the present study, we identified and confirmed the HBV integration breakpoints clustering at the C-terminal X gene is a tumor-specific event, and the C-terminal HBx is expressed more frequently in the tumors than normal liver tissues. Then, the oncogenic effect of the truncated HBx was validated in vitro and in vivo. Transcriptome sequencing revealed that TXNIP, as a downstream target of truncated HBx, negatively regulates glucose metabolism. Screening of public database and our clinical cohort exhibited that TXNIP is significantly down-regulated in HCC patients with truncated HBx expression, compared to those with full-length HBx expression and HBV-negative patients. Lower expression of TXNIP is negatively correlated with patient survival. We also reported evidence that truncated HBx down-regulates TXNIP expression by transactivation via the transcriptional repressor NFACT2. Additionally, the re-introduction of TXNIP inhibited the metabolic reprogramming from mitochondrial respiration to aerobic glycolysis induced by truncated HBx and further resulted in HCC growth arrest in vitro and in vivo. In summary, our finding proposes a promising diagnostic and therapeutic strategy for HBV-induced HCC.
Citation Format: Yu Zhang. Glucose metabolic reprogramming in HBV-related hepatocellular carcinoma through C-terminal truncated HBx protein suppression of TXNIP [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 5991.
Abstract 60: Semaphorin 7a promotes cell survival and resistance to endocrine therapy in ER+ breast cancer
Authors: Lyons Traci Renae 
Published: September 2020

Abstract
Estrogen receptor positive (ER+) breast cancers comprise the largest percentage, ~70%, of all breast cancers diagnosed in the Unites States. Despite the development of effective anti-estrogen based therapies, such as tamoxifen, aromatase inhibitors, and fulvestrant, 1 in 5 women with an ER+ tumor will experience recurrence within 10 years of diagnosis. Thus, the largest number of breast cancer-related deaths each year are attributed to ER+ breast cancers. Additionally, metastatic ER+ breast tumors uniformly develop resistance to anti-estrogen-based therapies, including combination targeted therapies with CDK4/6 and mTOR inhibitors, which represent some of the best therapeutic advances of the last five years and reflect our increasing understanding of cross-targeting to overcome acquired resistance. Our studies have shown that Semaphorin 7a expressing tumors are resistant to ER targeting therapies, including tamoxifen and fulvestrant. Furthermore, Semaphorin 7a expressing tumors do not respond to CDK4/6 inhibition. We have utilized luciferase reporter assays to show that Semaphorin 7a is initially regulated by ER; we then utilized overexpression studies to show that sustained upregulation of Semaphorin 7a results in downregulation of ER in xenograft models. This downregulation of ER is accompanied by upregulation of cell survival signaling mediated by pro-survival kinase Akt. In TCGA and METABRIC datasets, Semaphorin 7a expression is associated with significant decreases in overall survival. Furthermore, using KmPlot analysis, we have shown that Semaphorin 7a expression in patients treated with endocrine therapy predicts for poor survival rates. Thus, we sought to determine whether Semaphorin 7a expressing tumors would be susceptible to PI3K/Akt targeted therapies. We observe that Semaphorin 7a expressing tumors are sensitive to PI3K/Akt inhibition, as well as to inhibition of the ER target gene Bcl2. Thus, we suggest that patients with high Semaphorin 7a expression be considered as candidates for the addition of Venetoclax, an FDA approved Bcl2 targeted therapy, to their current therapeutic regimen. As Venetoclax is in Phase II trials in combination with fulvestrant for advanced CDK4/6 inhibitor refractory breast cancer, we believe our results could be rapidly translated to the clinical setting and will improve outcomes for the thousands of ER+ breast cancer patient that develop resistance to endocrine therapy.
Citation Format: Traci Renae Lyons. Semaphorin 7a promotes cell survival and resistance to endocrine therapy in ER+ breast 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 60.