bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract 1442: Targeting ATM kinase and mTOR signaling reverses bone marrow stromal cell-mediated protection of FLT3-ITD AML from FLT3-targeted therapy
Authors: Park Hae J. , Gregory Mark A. , Zaberezhnyy Vadym , DeGregori James 
Published: July 2021

Abstract
Internal tandem duplication (ITD) mutations in FMS-like tyrosine kinase 3 (FLT3) are among the most common mutations in acute myeloid leukemia (AML) and are associated with poor prognosis. FLT3-ITD causes constitutive activation of FLT3, and the strong evidence that activated FLT3 drives leukemogenesis has led to the development of several FLT3-targeted inhibitors. However, clinical studies of FLT3-targeted inhibitors have demonstrated much more effective clearing of leukemic burden in the periphery than in the bone marrow, implicating the bone marrow microenvironment as a potential contributor to drug resistance. As previously reported, the conditioned media of human bone marrow stromal cells (CM-BMSC) protects human FLT3-ITD AML cells from the killing effect of FLT3-targeted therapy despite complete inhibition of FLT3. We further show that genetic knockdown of Ataxia Telangiectasia Mutated (ATM) in combination with FLT3 inhibition substantially reverses the protection from cell death mediated by CM-BMSC. While autophosphorylation activity of ATM is downregulated upon FLT3 inhibition in regular media, CM-BMSC prevented the loss of ATM activity. Interestingly, genetic knockdown of ATM in human FLT3-ITD AML cells impaired the activity of mTOR Complex 1, and unbiased analyses of gene expression and signaling pathways by RNA-seq analysis and Reverse Phase Protein Arrays (RPPA) showed that mTOR signaling is downregulated with FLT3 inhibition in regular media, coinciding with marked inhibition of the protein translation machinery. Both mTOR signaling and protein translation were maintained during FLT3 inhibition in the presence of CM-BMSC. Furthermore, human FLT3-ITD AML cells treated with mTOR inhibitor everolimus in combination with the FLT3 inhibitor quizartinib reversed the protection mediated by CM-BMSC, and combination therapies are currently being tested in mouse models. These data suggest that ATM kinase and mTOR signaling play a key role in bone marrow stoma-mediated protection against FLT3 targeted therapy. Findings from this research provide new insights into the mechanism of bone marrow stroma-mediated protection of FLT3-ITD AML from FLT3-targeted therapy, identifying additional candidates for combinatorial therapies designed to overcome the protective effects of bone marrow stromal cells and improve patient outcomes.
Citation Format: Hae J. Park, Mark A. Gregory, Vadym Zaberezhnyy, James DeGregori. Targeting ATM kinase and mTOR signaling reverses bone marrow stromal cell-mediated protection of FLT3-ITD AML from FLT3-targeted therapy [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 1442.
Abstract 1475: Discovery of ETS-001, a highly potent allosteric SHP2 inhibitor to treat RTK/RAS-driven cancers
Authors: Xia Xi , Du Lin , Zhuge Hao , Zheng Qiangang , Cui Wenqi , Zhu Jidong , Li Guo 
Published: July 2021

Abstract
The non-receptor protein tyrosine phosphatase (PTP) SHP2, encoded by PTPN11, functions as a convergent node downstream of multiple receptor tyrosine kinases (RTKs) and is required for full activation of the MAPK pathway. Suppression of SHP2 activity via either genetic silencing or pharmacological inhibition has been shown to inhibit RAS/MAPK signaling and cell growth in a wide spectrum of cancers, pointing to a therapeutic opportunity for targeting SHP2 in cancer therapy. Here we report the discovery of a highly potent, selective and orally bioavailable small-molecule allosteric inhibitor of SHP2, ETS-001, that is effective in various human cancer models bearing oncogenic alterations in the RTK/RAS/MAPK pathway. Treatment with ETS-001 as a single agent resulted in dramatic growth inhibition of cancer cells as well as in vivo tumor models bearing genetic alterations of EGFR, or components in the nucleotide cycling-dependent KRAS pathway. Besides, as the effectiveness of RAS pathway inhibitors are ultimately limited by rapid emergence of drug resistance via multiple mechanisms including bypass activation of alternative RTKs, SHP2 inhibition has the potential to overcome the resistance as combinational strategies associated with various RAS pathway-targeted therapies. Here we show that ETS-001 exhibited strong synergistic effect with EGFR-TKI (osimertinib), KRASG12Ci (AMG510) or CDK4/6i (ribociclib) in appropriate cancer models in vitro and in vivo. In EGFR mutant NSCLC cells, treatment with both ETS-001 and osimertinib showed combinational benefit that was coincident with sustained ERK inhibition. In a KRASG12C mutant pancreatic cancer cell xenograft model, ETS-001 greatly enhanced the efficacy of AMG510 to suppress in vivo tumor growth. In addition, combinational benefit of ETS-001 and ribociclib was observed in esophageal cancer models, which exhibited high frequency of concurrent oncogenic alterations in RTKs and cell cycle pathway. Taken together, our findings provide preclinical evidence that ETS-001 as a potent SHP2 inhibitor, alone or in combination with other targeted-therapy agents, can effectively inhibit MAPK activation and treat cancers with diverse oncogenic mutations in the RAS/MAPK pathway.
Citation Format: Xi Xia, Lin Du, Hao Zhuge, Qiangang Zheng, Wenqi Cui, Jidong Zhu, Guo Li. Discovery of ETS-001, a highly potent allosteric SHP2 inhibitor to treat RTK/RAS-driven cancers [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 1475.
Abstract 1524: Peripheral blood mononuclear cells engineered via microfluidic Cell Squeeze® technology to generate APCs that drive mutant-KRas-specific CD8+ T cell responses
Authors: Yarar Defne , Smith Carolyne , Ramakrishnan Amritha , Loughhead Scott , Sharei Armon , Seidl Katherine , Bernstein Howard 
Published: July 2021

Abstract
KRAS mutations are shared across multiple cancer types and are most commonly found in cancers of the lung, pancreas, and colon. While recently developed drugs blocking signaling driven by KRAS G12C mutations have shown promise in the clinic, there is a great need for therapies targeting the more common G12V and G12D mutations. We utilize our microfluidic Cell Squeeze® technology to deliver antigens directly into the cytosol of peripheral blood mononuclear cells (PBMCs) for the generation of cancer antigen-targeted cellular vaccines. This method bypasses the need for cross-presentation and directly enables efficient antigen presentation on MHC-I in multiple cell types. Murine and human in vitro studies have demonstrated that this allows SQZ PBMCs to drive CD8+ T cell activation. Here, we demonstrate the delivery of various antigens, including KRas-derived peptides containing the most common mutations (G12D and G12V) to PBMC cell subsets. In addition, we find that human PBMCs squeezed with either KRasG12V or KRasG12D peptides can specifically stimulate KRasG12V- and KRasG12D- reactive CD8+ T cell responders. When KRasG12V and KRasG12D peptides are co-delivered via microfluidic squeezing, the human PBMCs enable activation of CD8+ T cells of both specificities. This work with KRasmutant-presenting human PBMCs lays a strong foundation for developing a potentially potent cell therapy to treat KRASmutant associated cancers.
Citation Format: Defne Yarar, Carolyne Smith, Amritha Ramakrishnan, Scott Loughhead, Armon Sharei, Katherine Seidl, Howard Bernstein. Peripheral blood mononuclear cells engineered via microfluidic Cell Squeeze® technology to generate APCs that drive mutant-KRas-specific CD8+ T cell responses [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 1524.
Abstract 1537: CD70 knockout: A novel approach to augment CAR-T cell function
Authors: Dequeant Mary-Lee , Sagert Jason , Kalaitzidis Demetri , Yu Hui , Porras Ashley , McEwan Brigid , Padalia Zinkal , Tetteh Paul , Nguyen Thao , Dunn Andrew , Spencer Sarah , Lee Nicolette , Dar Henia , Henderson Daniel , Karnik Sushant , Keerthipati Pooja , Terrett Jonathan A. 
Published: July 2021

Abstract
CD70 and its ligand, CD27, have been described as both activating and suppressing for different cell types including B and T cells. There has been speculation that the CD70/CD27 axis can act in a checkpoint or co-stimulatory manner in certain immuno-oncology settings. Knockout (KO) of CD70 function scored highly in a CRISPR/Cas9 screen of candidate genes for enhanced T cell activity. Deletion of other checkpoint candidates such as PD1, TIM3, LAG3 and TIGIT scored much lower than CD70, both alone and in combination with each other. T cells with CD70 KO showed resistance to exhaustion upon repeated stimulation in culture. CAR-T cells with CD70 KO similarly showed exhaustion resistance, as well as a reduction in apoptosis, increased proliferation, and improved target cell lysis upon sequential rechallenges. CTX130 is an investigational allogeneic CAR-T therapy currently being studied in patients with CD70-expressing tumors, including clear cell renal cell carcinoma and B and T cell malignancies. CTX130 contains KOs of TRAC to avoid GvHD, B2M to protect the product from patient T cells, and CD70 for enhanced CAR-T performance. Comparing CTX130 with and without CD70 KOs shows that CAR-T cells with CD70 KO have increased potency, enhanced ability to withstand multiple tumor challenges in vivo, and increased resistance to overexpression of PDL1 on target cells. Interestingly, while CD70 surface expression may be extremely low or undetectable after manufacturing of CD70-targeted CAR-T cells without CD70 KO, the beneficial properties outlined here are only achievable when the CD70 gene is genetically knocked out. In summary, KO of CD70 confers benefit to CAR-T cells that far exceeds KO of other checkpoint related genes, and this benefit was present regardless of the antigen being targeted. CD70 KO is included in the CTX130 investigational allogeneic CAR-T therapy currently in clinical trials.
Citation Format: Mary-Lee Dequeant, Jason Sagert, Demetri Kalaitzidis, Hui Yu, Ashley Porras, Brigid McEwan, Zinkal Padalia, Paul Tetteh, Thao Nguyen, Andrew Dunn, Sarah Spencer, Nicolette Lee, Henia Dar, Daniel Henderson, Sushant Karnik, Pooja Keerthipati, Jonathan A. Terrett. CD70 knockout: A novel approach to augment CAR-T cell function [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 1537.
Abstract 1578: Heating it up: Targeting RAS/RAF/PI3K pathway to make melanoma tumors ‘immunologically hot' and suitable for checkpoint blockade immunotherapies
Authors: Yan Chi , Saleh Nabil , Nebhan Caroline , Vilgelm Anna E. , Reddy E. Premkumar , Roland Joseph T. , Johnson Douglas B. , Shattuck-Brandt Rebecca L. , Chen Sheau-Chiann , Ayers Gregory D. , Richmond Ann 
Published: July 2021

Abstract
Immune checkpoint blockade (ICB) is the current first-line treatment for metastatic melanoma. However, ICB fails in many patients and has dangerous side effects. Rigosertib (RGS), a non-ATP-competitive small molecule RAS mimetic, has the potential to block oncogenic RAS-RAF-MEK-ERK and/or PI3K-AKT-mTOR signaling pathways. Using immunocompetent mouse models of B16F10 (BRAFwt) and YUMM3.3 (BRAFmut) melanoma, we identified that RGS treatment (300mg/kg) of melanoma tumor-bearing mice is well tolerated and results in ~50% inhibition of tumor growth as monotherapy and ~70% inhibition in synergy with αPD1+αCTLA4. RGS-induced tumor inhibition depends on the induction of CD40 expression on melanoma cells, followed by immunogenic cell death, leading to an inflamed tumor microenvironment with enrichment of dendritic cells and activated CD8+ Tc cells. The RGS-initiated suppression of tumor growth was partially reversed by either suppression of CD40 expression in the melanoma cells by shRNA, or depletion of CD8+ Tc cells. Analysis of multiple published patient melanoma studies confirms that a high CD40 expression level correlates with CD80, ICOS-L, beneficial type-I T-cell responses, and better survival in melanoma patients. The CD40 levels in melanoma cells are prognostic for therapeutic response to RGS, RAF inhibitor and ICB. Notably, multiplex IHC analysis showed that BRAF inhibitor treatment significantly induces CD40+SOX10+ melanoma cells in the tumors of melanoma patients and patient-derived xenografts. Our preclinical data support the therapeutic use of RGS plus αPD1+αCTLA4 in RAS/RAF/MEK and/or PI3K pathway-activated melanoma tumors and point to the need for clinical trials to determine the clinical benefit of RGS plus ICB for metastatic melanoma patients who do not respond to ICB alone.
The authors sincerely thank Onconova Therapeutics, Newtown, PA 18940 for kindly supplying Rigosertib for this work.
Citation Format: Chi Yan, Nabil Saleh, Caroline Nebhan, Anna E. Vilgelm, E. Premkumar Reddy, Joseph T. Roland, Douglas B. Johnson, Rebecca L. Shattuck-Brandt, Sheau-Chiann Chen, Gregory D. Ayers, Ann Richmond. Heating it up: Targeting RAS/RAF/PI3K pathway to make melanoma tumors ‘immunologically hot' and suitable for checkpoint blockade immunotherapies [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 1578.
Abstract 1664: Inhibition of arginase in combination with radiation therapy shows increased immune-activation and anti-tumor activity in syngeneic tumor models
Authors: Schuller Alwin , Doshi Aatman , Cantin Susan , Griffin Matt , Martin Maryann San , Proia Theresa , Reimer Corinne , Mlynarski Scott , Finlay Ray , Shao Wenlin 
Published: July 2021

Abstract
The tumor microenvironment (TME) has multiple mechanisms of immune-suppression including recruitment of arginase (ARG) expressing myeloid cells. ARG is an enzyme that catalyzes hydrolysis of L-arginine into urea and L-ornithine. Given L-arginine is essential for optimal function of both T cells and natural killer (NK) cells, inhibition of ARG has been recognized as a potential therapeutic approach to reverse immune-suppression and optimize anti-tumor immunity. We recently presented development of a novel ARG inhibitor, AZD0011, and demonstrated immune activation and anti-tumor activity as single agent and in combination with a-PD-L1 in various tumor models. We now expand these findings demonstrating combination benefit with radiation therapy. Radiation therapy (5 gray on day 6 and 9 after tumor cell implant) demonstrated an increase of both the number of arginase expressing myeloid cells, and NK cells in the TME of Lewis Lung (LL) tumors. Immuno-histochemistry also demonstrated a redistribution of the location of ARG positive myeloid cells with a marked increase at the edge of the tumor. LL tumor bearing mice receiving either AZD0011 (30 mg/kg twice daily), or radiation therapy as monotherapy did not show a significant anti-tumor response reaching 0.3% and 28% tumor growth inhibition (TGI) respectively (p&gt;0.05 versus vehicle). In contrast, combination treatment showed a marked increased efficacy averaging 60% TGI (p&lt;0.05 versus either monotherapy). Combination treatment also further increased several markers of immune activation including a doubling of the number of IL2+ or IFNg+ CD4+ and CD8+ T-cells in tumor draining lymph nodes. In summary, our pre-clinical data demonstrates that radiation therapy increases the number and location of intra-tumoral ARG expression myeloid cells and increased anti-tumor activity when combining the ARG inhibitor AZD0011 with radiation therapy.
Citation Format: Alwin Schuller, Aatman Doshi, Susan Cantin, Matt Griffin, Maryann San Martin, Theresa Proia, Corinne Reimer, Scott Mlynarski, Ray Finlay, Wenlin Shao. Inhibition of arginase in combination with radiation therapy shows increased immune-activation and anti-tumor activity in syngeneic tumor models [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 1664.
Abstract 1736: Antigen-specific targeting of tissue-resident gamma delta T cells with recombinant butyrophilin heterodimeric fusion proteins
Authors: de Silva Suresh , Fromm George , Lai Anne , Gonzalez Louis , Patel Arpita , Yoo Kyung Jin , Johannes Kellsey , Evans Kinsley , Wilson Keith , Schreiber Taylor H. 
Published: July 2021

Abstract
A major mechanism of acquired resistance to immune checkpoint inhibition involves downregulation of antigen presentation, including the MHC I complex itself. Downregulation of antigen presentation on MHC I can render tumor cells invisible to any α/β T cell directed therapy. γδ T cells (γδT) are a small subset of the overall T cell compartment, but are characterized by increased cytolytic capacity relative to α/β T cells. Rather than MHC I, γδT recognize target cells via a complex of heterodimerized butyrophilin (BTN) proteins. Thus, display of BTN heterodimers on the surface of tumor cells may enhance immunity to tumors that have downregulated MHC I, or which express low abundance or low affinity antigens.
We have previously reported the generation of a heterodimeric BTN protein targeting the CD19 antigen, referred to as BTN2A1/3A1-Fc-CD19scFv. While the BTN2A1/3A1 complex is a potent activator of γδT expressing the Vγ9δ2 T cell receptor (TCR), which is the major γδT population in human peripheral blood, Vγ9δ2 T cells are not the predominant γδT in many tissues. The murine equivalent of BTN2A1/3A1-Fc-CD19scFv, BTNL1/6-Fc-CD19scFv, stimulated specific proliferation and increased the cytolytic capacity of peripheral blood γδT in mice, but not other tissue-restricted GDT populations. These data suggested that distinct BTN heterodimers may preferentially activate tissue-restricted subsets of GDT.
To characterize potential differences between peripheral blood and tissue-restricted γδT , we performed a multi-layered analysis, including single-cell sequencing of γδ TCR from paired peripheral blood and tumor tissues from human cancer patients such as melanoma, prostate and colon cancer. These data identified tissue-specific preferences for individual γδ TCRs, with corresponding tissue-specific preferences for individual BTN proteins. Based on this information, we generated a panel of distinct heterodimeric BTN proteins, and show that specific γδT populations are preferentially activated by specific BTN heterodimers in a lock-and-key fashion. These data are a necessary pre-requisite for designing γδT specific therapeutics that may target both immune neglected and acquired resistant tumors that have limited visibility to α/β T cell directed approaches.
Citation Format: Suresh de Silva, George Fromm, Anne Lai, Louis Gonzalez, Arpita Patel, Kyung Jin Yoo, Kellsey Johannes, Kinsley Evans, Keith Wilson, Taylor H. Schreiber. Antigen-specific targeting of tissue-resident gamma delta T cells with recombinant butyrophilin heterodimeric fusion proteins [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 1736.
Abstract 1825: SAR443216, a novel trispecific T cell engager with potent T cell-dependent cytotoxicity for HER2-low tumors
Authors: Sha Wenwen , Vadde Sri , Song Zhili , Seung Edward , Xing Zhen , Chen Liqing , Cortez-Retamozo Virna , Sidhu Sukhvinder , Bangari Dinesh , Wu Lan , Wei Ronnie , Yang Zhi-yong , Nabel Gary , Pelekanou Vasiliki , Sanicola-Nadel Michele , Masciari Serena , Wiederschain Dmitri , Pao Lily 
Published: July 2021

Abstract
Current HER2-targeted therapies have markedly improved the outcome of cancer patients with HER2 overexpressing tumors. However, these patients may eventually relapse or develop treatment resistance. In addition, HER2-low patients that are not eligible for treatment constitute a significant portion of the breast cancer patients. To address these unmet needs, we have developed a novel HER2-targeting T cell engager, SAR443216. This is a trispecific antibody with binding sites for HER2, CD3 and CD28, and containing a mutated IgG4-Fc which lacks effector functions. CD28 binding contributes to T cell activation, including activation of IL-2 and NFκB pathways, as well as induction of anti-apoptotic protein, Bcl-xL. In the presence of HER2-positive cancer cells, SAR443216 is able to activate primary human CD4 and CD8 T cells, resulting in T cell proliferation and secretion of cytokines and granzyme B. Moreover, it has potent in vitro T cell-dependent cellular cytotoxicity (TDCC) against a panel of HER2-expressing cancer cell lines, including those that are HER2-low. The potency of in vitro TDCC is largely correlated with HER2 surface expression in the target cells. Finally, in a HER2-low breast cancer xenograft model, SAR443216 also exhibited significant anti-tumor activity in immuno-deficient NSG mice reconstituted with primary human T cells. Thus, SAR443216 represents a promising new drug for cancer patients with HER2-expressing tumors, including those who are currently ineligible for stand-of-care therapy.
Citation Format: Wenwen Sha, Sri Vadde, Zhili Song, Edward Seung, Zhen Xing, Liqing Chen, Virna Cortez-Retamozo, Sukhvinder Sidhu, Dinesh Bangari, Lan Wu, Ronnie Wei, Zhi-yong Yang, Gary Nabel, Vasiliki Pelekanou, Michele Sanicola-Nadel, Serena Masciari, Dmitri Wiederschain, Lily Pao. SAR443216, a novel trispecific T cell engager with potent T cell-dependent cytotoxicity for HER2-low tumors [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 1825.