bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract 2546: Targeting MerTK-mediated efferocytosis in the prostate cancer TME
Authors: Myers Kayla V. , de Groot Amber E. , Gonye Anna L. , Loftus Luke V. , Amend Sarah R. , Pienta Kenneth J. 
Published: June 2022

Abstract
The prostate cancer tumor microenvironment (TME) is comprised of many different components and cell types that influence tumor progression and patient outcome. Macrophages are highly abundant immune cells in the prostate cancer TME. Macrophage phenotypes can be modeled on a continuous spectrum of M1-like (anti-tumor macrophages) to M2-like (pro-tumor macrophages) and most macrophages in the prostate cancer TME are M2-like. Efferocytosis, the phagocytosis of apoptotic cells, is a pro-tumor function of M2-like macrophages. We have developed a flow cytometry assay to quantify efferocytosis of the prostate cancer cell line LNCaP. With both cell line-based THP-1 macrophages and human monocyte-derived macrophages (HMDMs), we observe that M2 macrophages efferocytose LNCaP cells more than M1 macrophages. Based on literature from other models and contexts, efferocytosis further supports the M2-like phenotype. Efferocytosis also prevents the apoptotic cell from progressing to secondary necrosis, which would attract an M1-like macrophage phenotype. Due these aspects, we hypothesize efferocytosis in the prostate cancer TME is a tumor-promoting function of macrophages. Following efferocytosis of LNCaP cells by M2 HMDMs, we detect a decrease in the M1-like, anti-tumor marker CD80 and an increase in M2-like, pro-tumor markers CD206 and PDL1. Due to this role in modulating macrophage phenotype, we hypothesize targeting efferocytosis will slow prostate cancer growth and promote an anti-tumor immune infiltrate, including M1-like macrophages. MerTK is a receptor tyrosine kinase that mediates efferocytosis by binding phosphatidylserine on apoptotic cells. At both the protein and mRNA level, we detect higher MerTK expression in M2 than M1 THP-1 macrophages and HMDMs. Upon addition of apoptotic LNCaP cells, we observe an increase in phosphorylated MerTK (active form), suggesting the role of MerTK in prostate cancer cell efferocytosis. Currently, we are targeting MerTK to block prostate cancer cell efferocytosis in vitro and in vivo. We have generated a Mertk-/-, Hi-Myc mouse model on the FVB/N background. This prostate cancer GEMM will be used to assess the role of MerTK across different stages of prostate cancer progression. We will be comparing tumor size and immune infiltration between Mertk+/+ and Mertk-/- Hi-Myc mice aged to 2 months, 6 months and 12 months. We predict that the Mertk-/- mice will have smaller tumors and an overall anti-tumor immune infiltrate compared to Mertk+/+ mice in this model due to lack of efferocytosis.
Citation Format: Kayla V. Myers, Amber E. de Groot, Anna L. Gonye, Luke V. Loftus, Sarah R. Amend, Kenneth J. Pienta. Targeting MerTK-mediated efferocytosis in the prostate cancer TME [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2546.
Abstract 2554: Impact of the aged bone marrow on the anti-tumor response to melanoma
Authors: Carey Alexis Erasta , Chhabra Yash , Fane Mitchell , Hueser Laura , Marino Gloria , Zabransky Daniel , Weeraratna Ashani 
Published: June 2022

Abstract
Melanoma is responsible for the most skin cancer-related deaths in the United States. Melanoma occurrence and severity increase with age while the anti-tumor responses decrease. There have been robust responses to immunotherapy treatments, however, there remains a subset of patients who do not benefit from these modalities. Understanding more about immune cell development and age-related changes in the bone marrow can improve patient outcomes. Our hypothesis suggests that during aging, changes in Wnt signaling reshape the aged bone marrow niche, driving precursor cells to become suppressive. This ultimately decreases the anti-tumor response to melanoma due to the skewing of hematopoiesis to yield decreased immune function. In a young and aged setting, we assess the effect of a Wnt inhibitor, sFRP1, on the development of immune cell subtypes by using flow cytometry. We have preliminarily observed in situ that sFRP1 is increased in the aged bone marrow through immunohistochemical staining. We also saw a decrease in CD4 and CD8 T-cells and an increase in CD11b positive myeloid cells in the tumors of young mice treated with recombinant sFRP1 compared to age-matched mice treated with PBS by using immunohistochemical staining. We hypothesize that the increase in sFRP1 in the bone marrow niche will impact immune cell development in the niche and the immune response at the tumor site. As a future direction, we plan to investigate combination treatments of anti-sFRP1 with immunotherapies, such as anti-PD-1. These insights could lead to improve outcomes for elderly patients with melanoma.
Citation Format: Alexis Erasta Carey, Yash Chhabra, Mitchell Fane, Laura Hueser, Gloria Marino, Daniel Zabransky, Ashani Weeraratna. Impact of the aged bone marrow on the anti-tumor response to melanoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2554.
Abstract 2582: Regulatory T cells restrain efficacy of immunotherapy in murine liver tumors
Authors: Green Benjamin L. , Ma Chi , Zhang Qianfei , Ruf Benjamin , Rosato Umberto , Qi Jonathan , Wabitsch Simon , Bauer Kylynda , Myojin Yuta , McCallen Justin , McVey John C. , Subramanyam Varun , Catania Vanessa , Nur Amran , Korangy Firouzeh , Xie Changqing , Greten Tim F. 
Published: June 2022

Abstract
Background: Checkpoint blockade immunotherapy (CBI) can induce a durable response for some patients with hepatic tumors, but many derive no or incomplete oncologic benefit for unclear reasons. Regulatory T cells (Tregs) in the liver play a central role in maintaining the tolerogenic local immune environment, both in homeostasis and disease. Here we sought to explore the impact of CBI on hepatic Tregs to determine if they play a role in CBI resistance of liver tumors in mice.
Methods: High-dimensional flow cytometry was used to examine the ex vivo characteristics of lymphocytes from both tumor-free and orthotopic tumor-bearing livers of mice treated with CBI or other immunomodulatory agents.
Results: All hepatic T cell subsets examined displayed higher proliferative and apoptotic indices compared with those of splenic T lymphocytes. We found that hepatic Tregs intensely proliferate and undergo apoptosis compared with splenic Tregs under homeostatic conditions. Hepatic Treg proliferation was enhanced after administration of CBI treatment. This effect was abrogated by co-treatment with sirolimus. CD8, macrophages, and the gut microbiome were found to be dispensable for the in vivo in response to αPD1. Co-treatment of mice with αPD1 and αCD25 sensitized MC38-bearing liver tumors.
Conclusion: Murine liver Tregs naturally proliferate and undergo apoptosis due to the mTOR rheostat at homeostasis making them highly responsive to CBI. This behavior potentially explains liver-specific CBI-resistance in tumors.
Citation Format: Benjamin L. Green, Chi Ma, Qianfei Zhang, Benjamin Ruf, Umberto Rosato, Jonathan Qi, Simon Wabitsch, Kylynda Bauer, Yuta Myojin, Justin McCallen, John C. McVey, Varun Subramanyam, Vanessa Catania, Amran Nur, Firouzeh Korangy, Changqing Xie, Tim F. Greten. Regulatory T cells restrain efficacy of immunotherapy in murine liver tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2582.
Abstract 2596: Impact of novel Ku-DNA binding inhibitors on the DNA DSBs-induced DNA damage response
Authors: Mendoza-Munoz Pamela L. , Gavande Navnath S. , VanderVere-Carozza Pamela S. , Pawelczak Katherine S. , Dynlacht Joseph R. , Garrett Joy E. , Turchi John J. 
Published: June 2022

Abstract
The DNA-dependent protein kinase (DNA-PK) plays a critical role in the non-homologous end joining (NHEJ) double-strand break (DSB) repair pathway and the DNA damage response (DDR). Consequently, blocking DNA-PK kinase activity is a novel anti-cancer therapeutic strategy in combination with ionizing radiation (IR). Towards developing a new class of DNA-PK inhibitors, our laboratory has exploited the mechanism of DNA-PK activation which requires binding to DNA termini via the Ku 70/80 heterodimer. We have previously reported the development of Ku-DNA binding inhibitors (Ku-DBi’s) that act via this novel mechanism of action to inhibit DNA-PK catalytic kinase activity. Ku-DBi’s display nanomolar activity in vitro, possess cellular DNA-PK and NHEJ inhibitory activity and sensitize non-small cell lung cancer (NSCLC) cells to DSB generating chemotherapeutics bleomycin and etoposide. In this study, we demonstrate that pre-incubation of our novel Ku-DBi’s can potentiate the cellular effects of bleomycin and IR and also induce p53 phosphorylation through the activation of the ATM pathway, which is concomitant with a decrease in DNA-PKcs autophosphorylation events at the S2056 (pS2056) cluster. Using a combination of Western blot and immunofluorescence assays in the NSCLC NCI-H460 and A549 cell lines, Ku-DBi’s treatment in combination with DNA DSBs-inducing agents such as bleomycin and IR, showed a significant reduction of autophosphorylation events of DNA-PKcs at the S2056 cluster compared to DNA DSBs-inducing agent alone. In addition, analysis of phospho-ATM and phospho-p53 protein levels in these NSCLC cell lines, suggested activation of the ATM pathway as a function of Ku-DBi’s treatment followed by bleomycin, evidenced by an increase of phosphorylation of ATM at Ser1981, and a modest increase of p53 phosphorylation at Ser15. Our findings demonstrate that Ku-DBi’s block DNA-DSB dependent DNA-PKcs autophosphorylation, resulting in potentiating cellular sensitivity to bleomycin and IR, and a likely effect on the ATM-dependent signaling pathway. These data are consistent with Ku-DBi’s possessing a novel mechanism of action that abrogates autophosphorylation of DNA-PKcs to impact DSB repair and potentially DDR signaling, becoming in a promising approach as part of an anticancer therapeutic strategy in combination with DNA DSBs-inducing agents.
Citation Format: Pamela L. Mendoza-Munoz, Navnath S. Gavande, Pamela S. VanderVere-Carozza, Katherine S. Pawelczak, Joseph R. Dynlacht, Joy E. Garrett, John J. Turchi. Impact of novel Ku-DNA binding inhibitors on the DNA DSBs-induced DNA damage response [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2596.
Abstract 265: Inhibiting proteasome in extracellular matrix (ECM) detached cells promotes anoikis
Authors: Adeshakin Funmilayo , Zhang Guizhong , Adeshakin Adeleye , Wan Xiaochun 
Published: June 2022

Abstract
The underlying mediators for altered cell-extracellular matrix (ECM) communication in tumors remain to be understood and are likely to be multifactorial. Detached cells from the ECM are often cleared by a death process called ‘anoikis’. Anoikis is critical for health and homeostasis maintenance. However, aggressive cancer cells acquire anoikis resistance to promote invasion and metastasis in new sites. We previously identified metabolic reprogramming and upregulation of Vacuolar-ATPase members responsible for anoikis resistance while the manipulation of these pathways induced anoikis. However, the mechanisms underlying anoikis resistance and subsequent metastasis are yet to be fully elucidated, thus limiting anoikis-targeting drug exploration for metastasis control. Herein, our RNA-seq data revealed upregulated genes associated with proteasome activity (such as PSMA, PSMB, PSMD, and POMP) in ECM detached cancer cells compared to adherent cancer cells. Targeting this, using proteasome inhibitors (MG132 or bortezomib) in breast cancer, cervical, and melanoma cell lines sensitized cancer cells to anoikis through increased cellular, mitochondrial stress, and misfolded protein accumulation. Moreover, Bortezomib treatment in vivo in melanoma tumor model repressed metastasis. These data demonstrate proteasome activity is hijacked by ECM detached cancer cells to maintain proteostasis thus promoting anoikis resistance and metastasis. Regardless of the impressive outcome in treating hematological malignancies, proteasome inhibitors show little effect against solid tumors in several clinical trials that utilized selective and more potent inhibitors either as a single or in combinatory therapy. In this sense, our finding suggests proteasome inhibitors may be more attractive for metastasis control rather than local tumor treatment. Altogether, our findings demonstrate enhanced proteasome activity within the tumor cells is critical for anoikis resistance, and targeting this can markedly overcome resistance and control tumor metastasis.
Citation Format: Funmilayo Adeshakin, Guizhong Zhang, Adeleye Adeshakin, Xiaochun Wan. Inhibiting proteasome in extracellular matrix (ECM) detached cells promotes anoikis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 265.
Abstract 2671: ERAS-601, a potent allosteric inhibitor of SHP2, demonstrates anti-tumor activity in RAS/MAPK-driven tumor models
Authors: Martin Leenus , Patel Roopal , Zhang Jingchuan , Yang Jennifer , Nevarez Robin , Congdon Taylor , Brail Les , Shoemaker Robert 
Published: June 2022

Abstract
SHP2 is a non-receptor protein tyrosine phosphatase (PTP) encoded by the PTPN11 gene. SHP2 transduces upstream receptor tyrosine kinase (RTK) signaling to the RAS/MAPK pathway via its phosphatase-mediated regulation of guanine nucleotide exchange factors (GEFs). The modulation of GEF activity impacts the rate at which KRAS cycles from the inactive GDP-bound state to the active GTP-bound state. ERAS-601 is a potent, selective small molecule allosteric inhibitor of SHP2. ERAS-601 potently inhibits the wild type SHP2 protein with a biochemical IC50 of 4.6 nM. ERAS-601 is a selective SHP2 inhibitor and demonstrates no appreciable inhibition against any off-target kinase or phosphatase across panels of 300 kinases and 12 phosphatases. ERAS-601 inhibits the loading of active GTP-bound oncogenic RAS and inhibits RAS/MAPK pathway signaling as measured by pERK1/2 inhibition and DUSP6 mRNA. ERAS-601 demonstrates anti-proliferative activity across a panel of human cancer cell line models with oncogenic alterations in the RAS/MAPK pathway. In a mouse in vivo study, ERAS-601 achieves substantial systemic exposure and demonstrates inhibition of ERK1/2 phosphorylation and DUSP6 mRNA levels in the NCI-H358 xenograft model. ERAS-601 also inhibits tumor growth in multiple RAS/MAPK-driven CDX and PDX models that harbor EGFR, KRAS, BRAF Class III, and NF1LOF mutations. ERAS-601 is a potent and selective allosteric SHP2 inhibitor that demonstrates anti-tumor activity in vitro and in vivo and is currently being studied as a monotherapy in an ongoing Phase 1 clinical study in patients with advanced or metastatic solid tumors (FLAGSHP-1, NCT04670679).
Citation Format: Leenus Martin, Roopal Patel, Jingchuan Zhang, Jennifer Yang, Robin Nevarez, Taylor Congdon, Les Brail, Robert Shoemaker. ERAS-601, a potent allosteric inhibitor of SHP2, demonstrates anti-tumor activity in RAS/MAPK-driven tumor models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2671.
Abstract 2672: ERAS-007 is a selective ERK1/2 inhibitor with preclinical activity across RAS/MAPK pathway-driven CRC models
Authors: Lew Erin D. , Oh Joanne , Congdon Taylor , Zhang Jingchuan , Shoemaker Robert F. 
Published: June 2022

Abstract
Colorectal cancer (CRC) remains an unmet medical need where more than 50% off patients have tumors that are driven by somatic mutations in the RAS/MAPK signaling pathway. Targeted therapies, such as anti-EGFR inhibitors for patients with BRAFwt/RASwt CRC tumors and encorafenib + cetuximab for patients with BRAFV600E CRC tumors, are available treatment options but demonstrate both limited overall response rates and duration of response (Yaeger, 2018). In particular, in the previously treated setting, overall survival is typically less than a year (Grothey, 2013; Mayer, 2015; Kopetz, 2019). In addition, targeted treatment options are limited for patients harboring KRAS or NRAS mutations as emergence of these mutations is a predictive biomarker to anti-EGFR therapy resistance in metastatic CRC.
ERAS-007 is a selective ERK1/2 inhibitor targeting the terminal node of the RAS/MAPK signaling pathway. In addition, ERAS-007 demonstrates single digit nanomolar biochemical ERK1/2 inhibition as well as a durable target residence time, thus making it a promising combination partner in RAS/MAPK pathway activated or altered CRC. To this end, ERAS-007 was evaluated in preclinical models in combination with encorafenib + cetuximab in BRAFV600E CRC and with palbociclib in KRASmut CRC. ERAS-007 demonstrated monotherapy activity and combination benefit in cell-based assays as well as superior combination efficacy in vivo relative to respective monotherapy control arms.
In summary, ERAS-007 demonstrates promising preclinical activity across a wide range of RAS/MAPK pathway-driven CRC models both as a monotherapy and in combination that support further exploration in the clinic. Accordingly, ERAS-007 combinations with encorafenib + cetuximab in BRAFV600E CRC and with palbociclib in KRASmut CRC are currently being evaluated in the HERKULES-3 phase 1b/2 master protocol (NCT05039177).
Citation Format: Erin D. Lew, Joanne Oh, Taylor Congdon, Jingchuan Zhang, Robert F. Shoemaker. ERAS-007 is a selective ERK1/2 inhibitor with preclinical activity across RAS/MAPK pathway-driven CRC models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2672.
Abstract 2690: Loss of E-cadherin induces IGF1R activation revealing a targetable pathway in invasive lobular breast carcinoma
Authors: Elangovan Ashuvinee , Savariau Laura , Yates Megan E. , Hooda Jagmohan , Nagle Alison M. , Oesterreich Steffi , Atkinson Jennifer M. , Lee Adrian V. 
Published: June 2022

Abstract
Invasive Ductal Carcinoma (IDC) and Invasive Lobular Carcinoma (ILC) are two major subtypes of breast cancer with significant differences in their histological and molecular underpinnings. ILC has a unique loss of E-cadherin (CDH1) which we have previously demonstrated as a negative regulator of the Insulin-like Growth Factor 1 receptor (IGF1R) through a comprehensive analysis of cell line models and tumor samples. We propose that loss of E-cadherin in ILC sensitizes cells to growth factor signaling and thus alters their sensitivity to growth factor signaling inhibitors. To investigate this, we used CRISPR to generate CDH1 knockout (KO) IDC cell lines (MCF7, T47D, ZR75.1) to uncover the mechanism by which E-cadherin loss activates the IGF pathway while also assessing its targetability. CDH1 KO cells exhibited anchorage independent growth in suspension culture and altered p120 catenin localization as observed in ILC tumors. Through in vitro studies, we show increased signaling sensitivity to IGF/insulin ligands and enhanced signaling duration in CDH1 KO cells. In addition, we observed a higher migratory potential of CDH1 KO cells compared to wild type (WT) cells, which was further enhanced as a chemotactic response to IGF1 or serum. Further, this phenotype could be reversed with an IGF1R inhibitor, BMS-754807. We additionally identified an increase in Collagen I haptotaxis in the CDH1 KO cells, which was also translated into a novel invasive phenotype towards serum in the T47D CDH1 KO cells. Despite no significant differences in membranous IGF1R levels between WT and CDH1 KO cells, higher ligand-receptor interaction was observed with CDH1 KO cells, demonstrating an increased ligand-receptor complex formation upon stimulation. Our results suggest that loss of CDH1 results in an increase in IGF1 receptor availability for ligand binding which in turn allows for an enhanced downstream signaling activation. Interestingly, a physical repression of E-cadherin on IGF1R could not be demonstrated, suggesting spatial changes on the membrane following E-cadherin loss may control ligand binding. Critically, increased sensitivity to IGF1R, PI3K, AKT and MEK inhibitors was observed in CDH1 KO cells suggesting that these targets should be further explored in ILC and that CDH1 loss may be exploited as a biomarker of response, or for patient stratification to inhibitors targeting these pathways.
Citation Format: Ashuvinee Elangovan, Laura Savariau, Megan E. Yates, Jagmohan Hooda, Alison M. Nagle, Steffi Oesterreich, Jennifer M. Atkinson, Adrian V. Lee. Loss of E-cadherin induces IGF1R activation revealing a targetable pathway in invasive lobular breast carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2690.