bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract 487: Genomic difference of CD4 CD8 double-positive T cells versus conventional CD4 T cells and CD8 T cells in responders undergoing immunotherapy in advanced HCC
Authors: Ting Vox , Wong Carmen Chak-Lui , Kwong Yok Lam , Yau Thomas Chung Cheung 
Published: July 2021

Abstract
Intro: The number of undergoing clinical trials using more than one immune checkpoint inhibitor is rising rapidly. Previously, we have observed CD4 CD8 double-positive T cells (Figure 1) from checkpoint inhibitor responder in advanced HCC patient. To further investigate the genomic difference between CD4 CD8 double-positive T (DP T) cell and conventional CD4, CD8 T cells, we have applied GO, KEGG, and Reactone database to compare.
Material and method: Two responders showed a partial response to PD-1/PD-L1 inhibitor treatment with advanced HCC were included. DP T cells were measured with Carl Zeiss Laser Scanning Microscopy (LSM) 780 (Zeiss) at Faculty Core Facility. Blood samples from responders were stained with an antibody cocktail containing CD3, CD4 and CD8 T cells. To visualise the labelling cells, CD3, CD4 and CD8 surface fluorescence was shown in yellow, violet and green dots respectively. Conventional CD4, CD8 T cells and DP T cells were further sorted using the same staining protocol before extraction. RNA extraction were immediately applied after cell sorting, where CD4 CD8 double-negative T (DN T) cells were also included. All patients were seen at the Department of Medical Oncology, Queen Mary Hospitals. Blood samples were collected after the treatment along with clinical routine blood test.
Results: A total number of 3723 and 4653 genes respectively were differentially expressed in DP T cell versus CD8 T cell and DP T cell versus CD4 T cell in responder 1, whereas a total 11117 differential expressed genes were measured in DP T cell and DN T cell. In responder 2, a total number of 6439 genes were differentially expressed in DP T versus CD8 T cell, while a total number of 316 and 488 differential expressed genes were measured in DP T cell versus CD4 T cell and DP T cell versus DN T cell. GO, KEGG and Reactone database analysis indicated cytokine receptor, cell cytotoxicity and cell activation enrichment in DP T cell compared to conventional CD4 or CD8 T cell.
Citation Format: Vox Ting, Carmen Chak-Lui Wong, Yok Lam Kwong, Thomas Chung Cheung Yau. Genomic difference of CD4 CD8 double-positive T cells versus conventional CD4 T cells and CD8 T cells in responders undergoing immunotherapy in advanced HCC [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 487.
Abstract 492: CNTN4 is a novel immune checkpoint protein that inhibits proliferation of T cell by interacting with APP
Authors: Cha Mi Young , Jeon Bu-Nam , Jeong Areum , Chung Joo-Yeon , Yang Hyunsuk , Park Kyung Mi , Park Hansoo 
Published: July 2021

Abstract
Contactin 4 (CNTN4, alias BIG-2) is a glycosylphosphatidylinositol (GPI)-anchored neuronal membrane protein that functions as cell adhesion, playing a key role in maintaining the mechanical integrity and signaling properties of the synapse. However, its function and crosstalk with immune cells have not been investigated. Therefore, we tried to find out what role CNTN4 plays in cell adhesion between T cells and antigen-presenting cells (APC). CNTN4 has several binding partners such as the amyloid precursor protein (APP), amyloid-like protein 1 (APLP1), and protein tyrosine phosphatase receptor γ (PTPRγ). In previous papers, the APP was reported to be expressed in T cells. We investigated whether CNTN4 can bind to T cells. The degree of binding of CNTN4 to T cells varied depending on the expression level of APP, and that the binding between these two proteins was in the form of trans-binding. And it was confirmed that the direct binding is achieved through fibronectin 1~2 domain of CNTN4 and KPI (Kunitz protease inhibitor) domain of APP. Furthermore, we investigated whether CNTN4 has any effect on T cell proliferation. T cell proliferation and cytokine secretion assays by using CNTN4 recombinant protein showed that CNTN4 significantly inhibits proliferation and cytokine secretion (IL-2, IFN-γ, TNF-α) of T cells more than PD-L1. Although the expression of CNTN4 in immune cells has not yet been clearly confirmed, the expression of CNTN4 in various carcinomas have confirmed by using western, IHC, and bioinformatic data analysis. In particular, the higher the expression of CNTN4 in tumor tissues of gastric cancer patients, the worse the prognosis is in the survival curve. Our findings suggest that CNTN4 may behave as an immune checkpoint protein similar to other B7 family members. Further investigation of the CNTN4 signaling pathway and its receptors are warranted by our data and may lead to novel therapeutic interventions.
Citation Format: Mi Young Cha, Bu-Nam Jeon, Areum Jeong, Joo-Yeon Chung, Hyunsuk Yang, Kyung Mi Park, Hansoo Park. CNTN4 is a novel immune checkpoint protein that inhibits proliferation of T cell by interacting with APP [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 492.
Abstract 496: Humanized SIRPA and double humanized SIRPA/CD47 B-NDG mouse models are promising tools for anti-SIRPα antibody in vivo efficacy studies
Authors: Hu Yuting , Zhao Lei , Liu Yujie , Hui Li , Yu Zhaoxue (Luke) 
Published: July 2021

Abstract
The CD47/Signal regulatory protein α (SIRPα) axis regulates myeloid cell activation and functions as a crucial myeloid specific immune checkpoint. CD47 is highly expressed on many different types of cancer and upon binding with SIRPα which is abundantly expressed on myeloid cells, transduces inhibitory signals that protect cancer cells from phagocytosis by macrophages and other myeloid cells. Therefore, antibodies that block CD47 and SIRPα binding become encouraging tools for cancer immunotherapy. Biocytogen developed humanized SIRPα B-NDG mice and double humanized SIRPα/CD47 B-NDG mice to provide solid platforms for in vivo efficacy assessment of SIRPα antibodies with or without other immune checkpoint regulators. These mice have a B-NDG mouse background (completely lacking mature T, B and NK cells and were deficient in cytokine signaling) and express human SIRPα protein only or with human CD47 IgV domain and no mouse counterpart expressed. Raji-Luc cells were injected into these mouse models for tumor xenografting and anti-tumor efficacy of anti SIRPα antibody in combination with other antibodies was evaluated. The results showed that the combination of antibodies could effectively control tumor growth in the two mouse models. In addition, B-NDG hSIRPα/hCD47 mice can be used for toxicity assessment for SIRPα or CD47 antibodies. In summary, both B-NDG hSIRPA and B-NDG hSIRPA/hCD47 mice are promising models for preclinical in vivo evaluation of SIRPα antibodies and combined therapy.
Citation Format: Yuting Hu, Lei Zhao, Yujie Liu, Li Hui, Zhaoxue (Luke) Yu. Humanized SIRPA and double humanized SIRPA/CD47 B-NDG mouse models are promising tools for anti-SIRPα antibody in vivo efficacy studies [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 496.
Abstract 506: A homogenous PBMC ADCC bioassay enables bridging studies with ADCC reporter bioassays in immunotherapy monoclonal antibody development
Authors: Stecha Pete , Garvin Denise , Gilden Julia , Wang Jun , Grailer Jamison , Hartnett Jim , Krishnan Gopal B. , Fan Frank , Cong Mei , Cheng Zhijie Jey 
Published: July 2021

Abstract
Measurement of antibody-dependent cellular cytotoxicity (ADCC) is critical for understanding antibody Fc effector functions during monoclonal antibody development. Classic ADCC assays measure the short-term cytotoxicity of target cells, typically pre-loaded with radioactive or fluorescent dyes, after exposure to antibody bound primary PBMCs or NK cells. These assays are widely used in antibody discovery and characterization during early drug development. However, the reproducibility of these assays is not adequate and they have major issues on biosafety or weak assay sensitivity. Moreover, the use of primary effector cells makes them prone to donor variability, low-throughput and therefore not suitable for implementation in quality-control drug development. We previously developed an ADCC reporter bioassay using engineered ADCC effector cells and demonstrated its specificity and ability to measure ADCC mechanism of action. The assay is prequalified according to ICH guidelines; demonstrates precision, accuracy, linearity, and robustness; and is suitable for product release and stability studies in a quality-controlled environment. In order to enable bridging studies comparing primary PBMC-based ADCC assays and ADCC reporter bioassays, we report the development of an improved PBMC ADCC assay using ADCC-prequalified PBMCs and engineered HiBiT target cells for therapeutic monoclonal antibodies with Fc functions. When target cells expressing HaloTag-HiBiT are incubated with an antibody and PBMCs, the target cells are lysed and release HaloTag-HiBiT, which then bind to LgBiT in the detection reagent to form a functional Nano-luciferase to generate Bioluminescence signal. In addition, it can enable the quantitative measurement of antibody-mediated target cell lysis via specific HaloTag staining using a fluorescent HaloTag ligand by flow cytometry. We demonstrate that the new PBMC ADCC assay is simple, homogenous, highly sensitive, and gives a robust assay window, and is capable of measuring potency of rituximab, cetuximab or trastuzumab. Additionally, it shows antibody potency comparable with the ADCC reporter bioassay in ADCC bridging studies.
Citation Format: Pete Stecha, Denise Garvin, Julia Gilden, Jun Wang, Jamison Grailer, Jim Hartnett, Gopal B. Krishnan, Frank Fan, Mei Cong, Zhijie Jey Cheng. A homogenous PBMC ADCC bioassay enables bridging studies with ADCC reporter bioassays in immunotherapy monoclonal antibody development [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 506.
Abstract 526: Novel mechanisms of Neuropilin-1 inhibition result in improved tumor growth inhibition in vivo
Authors: Sethumadhavan Shalini , Zhu Eric , Fulgham Aaron , Abbassi Mandana , Apte Ameya , Liao Tiffany , Merriman Chengfeng , Molloy Katherine , Stein Caitlin , Hanna Amber , Geoghegan James , Prinz Bianka , Dai Hongyue , Hurov Jonathan , Huang Pearl , Blom Daniel 
Published: July 2021

Abstract
Background Cygnal Therapeutics, pioneer in exoneuronal biology, has identified the neuronal protein, Neuropilin-1 (NRP1) as a critical regulator of tumor growth and anti-tumor immunity. NRP1 is a co-receptor that complexes with diverse ligands and their cognate receptors. As such, it plays a role in multiple different biological processes, including axon guidance and angiogenesis. NRP1 contains two CUB domains (a1 and a2) involved in binding the ligand Semaphorin3A (SEMA3A), two Factor V/VIII domains (b1 and b2) involved in VEGF ligand binding and one MAM domain (c domain). While functional antibodies with anti-tumor activity have been generated against the SEMA3A and VEGF binding domains, targeting other domains of NRP1 has not been well-studied. For example, the c-domain of NRP1 has been implicated in the dimerization of NRP1, a prerequisite for functionality. Thus c-domain blockers might inhibit multiple signaling pathways required for tumor growth. Alternatively, binders targeting the interface of two different domains might allow for simultaneous blocking of multiple ligands. We therefore hypothesized that these novel binders to alternative regions of NRP1 such as the b1/b2 interface and the c-domain would have improved and significant anti-tumor activity.
Methods Antibodies with diverse binding characteristics were tested for in vivo anti-tumor activity in multiple syngeneic models, including anti-PD1 non-responsive models. Ability of these of the anti-NRP1 antibodies to elicit an adaptive immune response was evaluated.
Results Novel binders to alternative regions of NRP1 such as domain interfaces and the c-domain resulted in significant tumor growth inhibition in multiple syngeneic models. Additionally, the NRP1 antagonists induced a robust CD8 T cell response, indicating immune-stimulatory role of these antibodies.
Conclusions Cygnal has developed fully human monoclonal antibodies against previously untargeted domains of NRP1. These novel domain binders show remarkable inhibition of tumor growth in multiple syngeneic models and offer a novel means of therapeutic intervention in patients.
Citation Format: Shalini Sethumadhavan, Eric Zhu, Aaron Fulgham, Mandana Abbassi, Ameya Apte, Tiffany Liao, Chengfeng Merriman, Katherine Molloy, Caitlin Stein, Amber Hanna, James Geoghegan, Bianka Prinz, Hongyue Dai, Jonathan Hurov, Pearl Huang, Daniel Blom. Novel mechanisms of Neuropilin-1 inhibition result in improved tumor growth inhibition in vivo [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 526.
Abstract 591: Developing an immunofluorescence assay for detecting Rb and phospho-Rb on circulating tumor cells in breast cancer
Authors: Kumar Tanya , Thangavel Hariprasad , Abdulkareem Noor Mazin , Bhat Raksha , Trivedi Meghana V. 
Published: July 2021

Abstract
Endocrine therapies (ET) such as tamoxifen, fulvestrant, and aromatase inhibitors (AIs) are the standard-of-care first-line treatment in majority of estrogen receptor (ER)-positive breast cancers (BC). Recent clinical studies using cyclin-dependent kinase 4 and 6 inhibitors (CDK4/6i) plus AIs or fulvestrant have shown significant improvement in survival outcomes in patients with ER+ metastatic BC compared to standalone ETs. CDK4/6i exert their action by inhibiting the phosphorylation of retinoblastoma (Rb) protein and consequently inducing cell cycle arrest. However, not all patients respond to this combination therapy and those, who initially respond, eventually develop resistance. Emerging studies suggest that the intrinsic resistance to CDK4/6i could be due to the loss of Rb or its mutations. Therefore, CDK4/6i resistance can be evaluated by measuring expression of total and phospho-Rb and Rb mutations. However, repeated biopsies to evaluate biomarkers in tumors is not feasible in patients. In this research, we aimed to develop an immunofluorescence assay to evaluate the expression of Rb and phospho-Rb using circulating tumor cells (CTCs) which can help predict response and resistance to CDK4/6i. CTCs serve as representative of the tumor bulk in patients and animal models and allow for less-invasive, frequent blood collection and real-time monitoring of treatment response. MCF7 cells treated with vehicle or abemaciclib (500 nM) for 48 hours were spiked into blood from non-tumor bearing mice. The MCF7 cells-spiked blood was processed using ScreenCell® device and the cells were transferred to slides and stained with DAPI, pan-cytokeratin, CD45, estrogen receptor, Rb and phospho-Rb. Tumor cells were defined as pan-cytokeratin-positive, CD45-negative, and nuclear stain-positive cells. Various antibody combinations were examined to increase the sensitivity of the IF assay for individual markers as well as the multiplexed assay. We also developed quantitative assessment approach to detect per-cell intensity of various markers. Treatment with abemaciclib reduced the intensity of phospho/Total Rb from 2.6 +/- 0.6 to 0.8 +/- 0.2 units (p &lt; 0.05, t-test, n=8-9) in the vehicle-treated samples. There was no significant difference in the Rb intensity between the treatment groups. Ongoing studies focus on validation of the assay using preclinical models and clinical samples.
Citation Format: Tanya Kumar, Hariprasad Thangavel, Noor Mazin Abdulkareem, Raksha Bhat, Meghana V. Trivedi. Developing an immunofluorescence assay for detecting Rb and phospho-Rb on circulating tumor cells in breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 591.
Abstract 61: Transient "rest" reinvigorates exhausted CAR T cells via epigenetic remodeling
Authors: Weber Evan W. , Mackall Crystal 
Published: July 2021

Abstract
The efficacy of chimeric antigen receptor (CAR) T cell therapy is limited by T cell exhaustion, whereby continuous CAR signaling induces hierarchical loss of effector function. Current methods to mitigate exhaustion in cancer, like immune checkpoint blockade, are not efficacious when combined with CAR T cells. Thus, new therapeutic approaches that target CAR T cell exhaustion are needed. To test the hypothesis that transient cessation of CAR signaling reverses CAR T cell exhaustion, we engineered human T cells to express a drug-regulatable CAR that demonstrates a high degree of antigen-independent tonic signaling and induces hallmarks of exhaustion within 10 days. Using this in vitro model of CAR T cell exhaustion, we discovered that transient CAR downregulation and concomitant cessation of tonic CAR signaling (i.e. “rest”) resulted in profound phenotypic changes, including decreased inhibitory receptor expression and increased memory-associated markers. Upon CAR re-expression and tumor challenge, rested CAR T cells exhibited improved killing, cytokine secretion, and sensitivity to antigen in vitro, as well as enhanced in vivo potency following adoptive transfer into tumor-bearing mice. Similar results were achieved via pharmacologic treatment with the Src kinase inhibitor dasatinib, which potently and reversibly inhibits CAR signaling. RNA- and ATAC-sequencing revealed that rest induces global transcriptional and epigenetic reprogramming, wherein rested CAR T cells closely resembled healthy, non-exhausted CAR T cells. Notably, epigenetic reprogramming and functional reinvigoration in rested cells were dependent on the activity of the histone methyltransferase EZH2, indicating that epigenetic alterations are required for functional reversal of CAR T cell exhaustion. Finally, providing multiple periods of rest in vivo by toggling CAR expression or pulsing with dasatinib reversed hallmarks of CAR T cell exhaustion and lead to more durable anti-tumor responses in xenograft murine models. This work demonstrates that transient cessation of CAR T cell signaling can enhance anti-tumor potency by preventing or reversing exhaustion and challenges the paradigm that exhaustion is an epigenetically fixed state. These results also raise the prospect that targeting proximal TCR/CAR signaling kinases might represent a novel immunotherapeutic strategy for mitigating exhaustion in human CAR T cells.
Citation Format: Evan W. Weber, Crystal Mackall. Transient "rest" reinvigorates exhausted CAR T cells via epigenetic remodeling [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 61.
Abstract 716: Telehealth use among multiple myeloma patients during the COVID-19 pandemic
Authors: Sweeney Nathan W. , Goldsmith Scott R. , Ahlstrom Jennifer M. 
Published: July 2021

Abstract
Background:The rapid outbreak of coronavirus disease 2019 (COVID-19) led to delays of non-urgent or routine medical care. Regulatory waivers and policy changes from the Centers of Medicare and Medicaid Services (CMS) for the use of telehealth came as a solution to help fight the outbreak. The aim of this project was to survey the change in the frequency of use of telehealth services among multiple myeloma (MM) patients during the COVID-19 pandemic.
Methods:We utilized HealthTree Cure Hub For Multiple Myeloma (healthree.org) and invited patients with active MM cancer or precursor conditions to participate in an online survey. We analyzed patient responses to doctor visits, the use of telehealth before and after the COVID-19 pandemic, and whether they had sufficient access to their doctor.
Results:1,301 MM pts participated in the survey between April 15, 2020, and June 8, 2020. During the pandemic, 36% of patients indicated visiting with their physician less often than before, 2% visited more often, and 62% had no change in the frequency of their visits. The percent of patients responding “Sometimes” or “Yes” to the use of telehealth are reported here. Before the pandemic, 10% of patients used telehealth, while 62% of patients indicated using telehealth during the pandemic, a 523% increase. When asked if they had sufficient access to their MM healthcare provider 90% of patients indicated that they did, while 10% indicated they did not.
Conclusions:There were significantly fewer in-person visits during the COVID-19 pandemic likely due to the CDC-recommended physical distancing practices. During this time, telehealth use among MM patients dramatically increased compared to telehealth use before the pandemic. It is reasonable to assume that patients indicated having sufficient access to their healthcare provider as a result of patients receiving care through telehealth visits. The authors encourage readers to think more broadly about the benefits of telehealth. Maintaining sufficient access to one healthcare provider addressed in this abstract is only a fraction of the benefits telehealth offers. MM is a rare cancer and as a result, some states have few if any specialists. Maintaining telehealth policy changes made during the pandemic would remove geographical barriers and open access to specialists across the country.
Citation Format: Nathan W. Sweeney, Scott R. Goldsmith, Jennifer M. Ahlstrom. Telehealth use among multiple myeloma patients during the COVID-19 pandemic [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 716.