bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract 5272: Molecular analysis of Sunitinib resistant renal cell carcinoma after sequential application of Cabozantinib
Authors: Zaccagnino Angela , Vynnytska-Myronovska Bozhena , Stockle Michael , Junker Kerstin 
Published: September 2020

Abstract
Introduction: The tyrosine kinase inhibitors Sunitinib and Pazopanib have been established in firstline treatment of metastatic renal cell carcinoma (mRCC) patients especially in the good prognosis group. Despite the primary response many patients become resistant. Resistance mechanisms include activation of MET and AXL - downstream pathways have been reported. Cabozantinib (Cbz), a MET/AXL/VEGFR inhibitor, showed clinical benefits as second-line agent. However, why the therapy becomes ineffective and how the long-term administration with Sunitinib influences sensitivity of tumor cells towards Cbz remain to be answered.
Methods: We referred to previously generated Sunitinib -resistant cells (786-O/S) and their untreated counterpart (786-O/WT) to test effect of Cbz in vitro. Drug sensitivity was determined via WST-1 cell proliferation assay, whereas cell pathways analysis in response to Cbz was evaluated at different time points by means of immunoblotting.
Results: By challenging the two cell phenotypes with different concentrations of Cbz we found that the 786-O/WT cells were more sensitive to the drug in comparison to 786-O/S (IC50 value of 9.9 µM versus 12.2 µM, respectively). The 786-O/WT cells responded to short-term incubation with Cbz by decreasing the expression of the receptor MET and its downstream intracellular pathways: the activated Src (pSrc) and p38 MAPK (p-p38 MAPK). Besides, Erk protein showed a slight increased activity (pErk) after 8 and 24h drug exposure. In contrast, no significant regulation of MET, nor pSrc and p-p38 MAPK kinase expression was reported in the 786-O/S cells. Remarkably, pErk level was induced after Cbz incubation in a time-dependent manner. Finally, phosphorylated S6 (pS6) was used as a marker of PI3K/Akt/mTOR pathway. Cbz decreased the level of pS6 in 786-O/WT, while enhancing it in the 786-O/S cells.
Conclusions: Our work provides a preclinical model for sequential therapy in mRCC. The initial in vitro data confirmed Cbz as a potent tool to contrast the progress of RCC in the first-line setting. Still, switching to Cbz after Sunitinb resistance resulted in Erk and mTOR pathways activation and might be interpreted as overlapping survival mechanism. This ongoing work will provide a better knowledge of the protein expression patterns of possible cross-resistance in RCC by analyzing additional cell lines including Pazopanib-resistant ones.
Citation Format: Angela Zaccagnino, Bozhena Vynnytska-Myronovska, Michael Stockle, Kerstin Junker. Molecular analysis of Sunitinib resistant renal cell carcinoma after sequential application of Cabozantinib [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 5272.
Abstract 5280: Kinase fusions drive endocrine resistance in estrogen receptor-positive breast cancer
Authors: Liu Bo , Ross Dara S. , Schram Alison M. , Razavi Pedram , Lagana Stephen M. , Zhang Yanming , Scaltriti Maurizio , Bromberg Jacqueline F. , Ladanyi Marc , Hyman David M. , Drilon Alexander , Zahir Ahmet , Benayed Ryma , Hechtman Jaclyn F. , Chandarlapaty Sarat 
Published: September 2020

Abstract
Oncogenic kinase activation by gene fusions can promote cancer development and tumor progression, however, kinase fusions have not been characterized extensively in breast cancer. In this study, we characterized kinase fusions in a large cohort of 4854 breast cancer patients using clinical DNA and/or RNA next generation sequencing platforms. Twenty-seven cases harboring kinase fusions were identified, including 11 FGFR (5 FGFR2, 3 FGFR3, 3 FGFR1), 5 BRAF, 4 NTRK1, 2 RET, 2 ROS1, 1 ALK, 1 ERBB2, and 1 MET. Eight patients with a history of endocrine therapy had available pre-treatment samples, of which six were negative for kinase fusion, and ESR1 hotspot mutations were not observed in any of these kinase fusion-positive samples. These findings suggest a potential role for kinase fusions in endocrine therapy resistance and prompted us to model the kinase fusions in human breast cancer cell lines. Ectopic expression of LMNA-NTRK1 fusion kinase activated growth factor signaling cascades, including PI3K-AKT and MAPK-ERK pathways, and promoted hormone-independent growth in MCF7 and T47D cells. Enforced expression of the LMNA-NTRK1 fusion conferred resistance to the ER antagonist fulvestrant and combined treatment of fulvestrant and the Trk inhibitor larotrectinib completely blocked the growth of LMNA-NTRK+ breast cancer cells. Similarly, expression of the EML4-ALK fusion also activated growth factor signaling pathways and caused resistance to estrogen depletion and induced sensitivity to the ALK inhibitor, Ceritinib. Treatment of xenografted LMNA-NTRK1 expressing tumors confirmed the efficacy of the combined treatment of antiestrogen and NTRK1 inhibition in vivo. Two patients with acquired LMNA-NTRK1 fusions and metastatic disease received larotrectinib and demonstrated clinical benefit. Overall, our findings demonstrate that kinase fusions promote endocrine resistance in ER-positive breast cancer, and suggest that fusion screening in advanced breast cancer, particularly those with ER-positive breast cancer at progression on hormone therapy can identify rare tumors harboring targetable kinase fusions.
Citation Format: Bo Liu, Dara S. Ross, Alison M. Schram, Pedram Razavi, Stephen M. Lagana, Yanming Zhang, Maurizio Scaltriti, Jacqueline F. Bromberg, Marc Ladanyi, David M. Hyman, Alexander Drilon, Ahmet Zahir, Ryma Benayed, Jaclyn F. Hechtman, Sarat Chandarlapaty. Kinase fusions drive endocrine resistance in estrogen receptor-positive 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 5280.
Abstract 5303: GSTP1 positive prostate cancer
Authors: Vidal Igor D. , Glavaris Stephanie , Jones Tracy , Hicks Jessica , Trock Bruce J. , Yegnasubramanian Srinivasan , Nelson William , De Marzo Angelo M. 
Published: September 2020

Abstract
Introduction: GSTP1 is a member of the Glutathione-S-transferase family, known to be silenced by CpG island DNA methylation in approximately 90% of prostatic adenocarcinomas. However, the cases that are not densely methylated have not been extensively characterized in terms GSTP1 expression or clinico-pathological features.
Description of experimental procedures: We analytically validated an automated IHC assay against human GSTP1 using well-known cell line controls and human prostate cancer tissues. We examined 33 TMAs from 1296 prostatectomy patients using the index tumor with 4-fold redundancy from patients from 1993 to 2015. TMA slides stained for GSTP1 were scanned and uploaded to a web based image scoring platform (TMAJ). The images were reviewed by two different pathologists with expertise in prostate cancer. The scoring system followed a two-tiered approach, noted as positive (carcinomas with any nuclear and/or cytoplasmic staining), and as negative (carcinoma cells with no nuclear or cytoplasmic stain) in the presence of benign stromal or inflammatory cells that served as internal controls. The GSTP1 positive staining was correlated with Gleason grade groups, pathological stage, and age.
Results: After exclusion for inadequate tissue staining, GSTP1 was evaluated in 4326 TMA cores with carcinoma. GSTP1 IHC staining was positive in 190 cores (4.3%), corresponding to 75 patients (5.9% of patients had GSTP1 positive cancer). Of these 190 positive cores, 109 showed homogeneous (100% positive) tumor cell staining while 81 showed heterogeneous staining, with mixed positive and negative regions. In 43 patients (3.3%), all TMA cores containing carcinoma stained positively. In a number of standard slides from prostatectomies, GSTP1 positive IHC staining cases were also found to be positive for GSTP1 mRNA by in situ hybridization. There was no correlation between GSTP1 positive staining, Gleason grade group, pathological stage, margin status or patient age. Preliminary analysis in a subset of cases showed no correlation with TMPRSS2-ERG status or PTEN loss.
Conclusion: GSTP1 protein is present in approximately 5.9% of clinically localized prostate cancers and in approximately 50% of these positive cases, all TMA cores with carcinoma stained positively.
Citation Format: Igor D. Vidal, Stephanie Glavaris, Tracy Jones, Jessica Hicks, Bruce J. Trock, Srinivasan Yegnasubramanian, William Nelson, Angelo M. De Marzo. GSTP1 positive prostate 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 5303.
Abstract 5307: The impact of image analysis and multiplex hybridization on PD-L1 diagnostic case triage
Authors: Humphries Matthew P. , Bingham Victoria , Sidi Fatima Abdullahi , Craig Stephanie G. , McQuaid Stephen , James Jacquline , Salto-Tellez Manuel 
Published: September 2020

Abstract
Introduction: Immune checkpoint blockade therapy is a new paradigm in cancer treatment with durable tumor regression and prolonged stabilization of disease in patients with advanced cancers, including non-small cell lung cancer (NSCLC). However, clinical assessment using immunohistochemistry (IHC) remains complex and ambiguous.
Methods: PD-L1 IHC staining was performed as a routine clinical reflex test on 802 NSCLC cases over an 18 month period using an automated staining system with PD-L1 clone SP263. PD-L1 expression was assessed using image analysis (IA) by 2 individuals and concordance was evaluated between the recorded manual clinical score and the digitally generated score. Additionally, a subset of 330 samples, representing cases with either varying PD-L1 expression or difficulty in assessment, were stained by multiplex immunofluorescence. Sensitivity and specificity was compared between manual assessments of both chromogenic and multiplex IHC.
Results: PD-L1 expression by IA showed significant concordance (R²=0.8248) to manual assessment. Sensitivity and specificity was 86.8% and 91.4%, respectively. Discordant cases were mainly due to spurious or poor staining quality, difficult classification by IA and overabundant macrophages and a low IA detection threshold. Evaluation of IA scores 10-49% and &gt;70% revealed 96.8% concordance to manual assessment. Multiplex assessment enabled PD-L1+/CD68+ macrophages to be readily identified within PD-L1+/CK+ or PD-L1-/CK+ tumor nests. Manual assessment of multiplex vs. chromogenic IHC was highly concordant, with a sensitivity and specificity respectively of 97.8% and 91.8%.
Conclusions: Deployment of IA in routine PD-L1 IHC assessment of NSCLC represents a beneficial time saving process and could aid case triage saving &gt;50% of pathologist review time. However cases close to diagnostic thresholds still require a more comprehensive pathological evaluation. Multiplex IHC provides a higher level of confidence in PD-L1 assessment and could be offered for challenging cases by centers with access to appropriate expertise and specialist equipment.
Citation Format: Matthew P. Humphries, Victoria Bingham, Fatima Abdullahi Sidi, Stephanie G. Craig, Stephen McQuaid, Jacquline James, Manuel Salto-Tellez. The impact of image analysis and multiplex hybridization on PD-L1 diagnostic case triage [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 5307.
Abstract 5331: Targeted protein degradation for the treatment of TRK fusion-driven cancers
Authors: Han Xiaoran , Chen Liqun , Zhang Chengwei , Jiao Bingyang , Chen Yanke , Liu Jing , Plewe Michael , Wang Jialiang 
Published: September 2020

Abstract
Small molecule-mediated targeted protein degradation offers a systemic approach to deplete disease-causing proteins. The tropomyosin receptor kinase (TRK) family kinases are receptors for neurotrophic factors and primarily function in the central nervous system. As results of chromosomal rearrangement events, TRK kinases are re-expressed as fusion proteins and implicated in a wide diversity of human malignancies. These fusion proteins universally retain the kinase domain and function as key oncodrivers. Two TRK kinase inhibitors, entrectinib and larotrectinib, have been approved to treat TRK fusion-expressing cancers with compelling clinical evidence, highlighting the significance of TRK fusion kinases as oncology targets. In the current study, we report the development of selective TRK degraders. Lead compounds induced rapid degradation of different TRK fusion variants identified in patients at subnanomolar concentrations. Degradation of the fusion kinases significantly compromised TRK-dependent cancer cell growth with low nanomolar IC50. The lead compound exhibited approximately 16% oral bioavailability in mouse and effectively controlled TRK-driven xenograft tumor growth. Pharmacodynamic analysis demonstrated sustained degradation of the TRK fusion in xenograft tumors. Collectively, these findings provide the framework to develop a novel approach that modulates oncogenic TRK fusion kinases for cancer treatment.
Citation Format: Xiaoran Han, Liqun Chen, Chengwei Zhang, Bingyang Jiao, Yanke Chen, Jing Liu, Michael Plewe, Jialiang Wang. Targeted protein degradation for the treatment of TRK fusion-driven cancers [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 5331.
Abstract 5340: Novel small-molecule antagonists of the PD1/PD-L1 axis
Authors: Magnez Romain , Leleu-Chavain Natascha , Tardy Morgane , El Bouazzati Hassiba , Klupsch Fréderique , Bailly Christian , Millet Régis , Quesnel Bruno , Thuru Xavier 
Published: September 2020

Abstract
Immuno-therapy has become a leading strategy to fight cancer. Over the past few years, immuno-therapies using checkpoint inhibitor monoclonal antibodies (mAbs) against programmed death receptor 1 (PD-1) and programmed death ligand 1 (PD-L1) have demonstrated improved survival compared with chemotherapy. We describe the identification and characterization of an innovative series of synthetic compounds (named PyrDLones, patented) endowed with nanomolar activity against PD-L1. PyrDLones properties were characterized using several biophysical techniques including microscale thermophoresis (MST) and fluorescence resonance energy transfer (FRET) measurements. In vitro, selected small molecules demonstrate a high affinity for human PD-L1, potently disrupt the PD-L1:PD-1 interaction (&lt;2nM), and inhibit Src homology region 2 domain-containing phosphatase (SHP2) recruitment to PD-1 (&lt;4nM). As a result, upon binding to and inhibiting PD-L1, these molecules reactivate proliferation of CTL-L2 cells expressing PD-1 (EC50=44nM). More than 150 molecules have been synthesized and a dozen of highly potent “PD-L1 silencing compounds” have been identified, based on in vitro measurements. Structure-activity relationships have been defined and an in silico drug-target model supporting the mechanism of action has been built. Experiments are on-going to delineate further the molecular mechanism of action of the PyrDLones (drug-induced PD-L1 dimer formation), the cellular consequences of the PD-L1 silencing (reactivation of cytotoxic T cells in the tumor microenvironment) and to characterize their activity in vivo. In summary, we have discovered a novel series of potent, small molecule PD-L1 antagonists, amenable to the design of orally active drugs for immuno-therapy of cancers.
Citation Format: Romain Magnez, Natascha Leleu-Chavain, Morgane Tardy, Hassiba El Bouazzati, Fréderique Klupsch, Christian Bailly, Régis Millet, Bruno Quesnel, Xavier Thuru. Novel small-molecule antagonists of the PD1/PD-L1 axis [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 5340.
Abstract 5343: Experimental targeted alpha-particle therapy against liver metastasis of HER2-positive gastric cancer in mice
Authors: Hasegawa Sumitaka , Li Huizi Keiko 
Published: September 2020

Abstract
Gastric cancer (GC) is one of the common cancer type and a leading cause of cancer-related death worldwide. Liver metastasis of gastric cancer (LMGC) is often found in GC patients and a fatal condition that is hard to be cured. HER2 overexpression is detected in a subset of about 10-20% of GC. HER2-targeting antibody trastuzumab has been used clinically for the treatment against advanced GC positive for HER2. Recently, targeted alpha-particle therapy has emerged as a new therapeutic option of cancer. Radionuclide astatine-211 is produced by cyclotron and emits alpha-particle at its decay with about 7 hours-half-life. Alpha-particle beam induces irreparable DNA damages to kill the cells. Here we investigated the therapeutic efficacy and toxicities of At-211-armed trastuzumab in a mouse model of LMGC positive for HER2. Trastuzumab was conjugated with At-211 to produce alpha-emitting antibodies targeting HER2 ([At-211]-trastuzumab). To generate a mouse LMGC model, we injected luciferase-labelled HER2-positive human metastatic NCI-N87 GC cells into splenic vein of severe combined immunodeficiency mice. Bio-distribution data showed that the maximum uptake of [At-211]trastuzumab in the liver metastatic GC tumors was approximately 12% of injected dose per tissue gram at 24 hours after injection. [At-211]trastuzumab was excreted mostly in the urine. For experimental therapeutics, a single dose of systemic injection of [At-211]trastuzumab (1 MBq) significantly reduced a tumor burden in the liver to extend the survival of model mice significantly compared to controls. Transient leukocytopenia was observed in mice received 1 MBq of [At-211]trastuzumab at 5-7 days after injection. No body weight loss was so far found in the mice treated with [At-211]trastuzumab. No Biochemical abnormalities for Liver and kidney function were found. These data suggest that targeted alpha-particle therapy using [At-211]trastuzumab is effective for LMGC.
Citation Format: Sumitaka Hasegawa, Huizi Keiko Li. Experimental targeted alpha-particle therapy against liver metastasis of HER2-positive gastric cancer in mice [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 5343.
Abstract 5350: RBE, in vivo, for a 212Pb-conjugated anti-HER2/neu antibody
Authors: Liatsou Ioanna , Josefsson Anders , Cortez Angel , Hobbs Robert F. , Brayton Cory , Torgue Julien , Sgouros George 
Published: September 2020

Abstract
The relative biological effectiveness is defined as the absorbed dose ratio (Dref(x)/Dtest(x)) of a reference radiation, Dref, to a test radiation, Dtest, that leads to a particular biological end-point, x. The majority of reported RBE values are obtained from in vitro irradiation of cells in monolayer culture wherein clonogenic survival is the end-point. As alpha-particle emitter radiopharmaceutical therapy (RPT) becomes a viable cancer therapy modality, RBE determinations, in vivo, are essential to assessing the potential efficacy and toxicity of alpha-emitter RPT. The aim of the study was to obtain the relative biological effectiveness, RBE, for alpha-particle emissions delivered by Bi-212, following the decay of Pb-212, conjugated onto an anti-HER2/neu antibody. Photon irradiation (200 kVp, 13 mA, 4 Gy/min, 10 × 10 mm2 collimator), delivered by a small animal radiation research platform (SARRP) was used as the reference radiation to irradiate the femurs of 6-8 weeks old female, neu/N transgenic mice (MMTV-neu). The biological endpoint was the reduction in hematopoietic cells in the region of the femur used for the RBE calculation. Alpha-particle emissions were delivered to this region by administering 325 kBq (8.8 μCi) of 212Pb-TCMC-7.16.4 intravenously (tail vein). Mice were sacrificed (n=3) at 1-7 days post-212Pb-TCMC-7.16.4 antibody administration. The long bones (femurs) were harvested, fixed with formalin and counted for radioactivity. The samples were also examined for histopathologic changes to assess the marrow cellularity. Clinical chemistry and hematological analysis were also performed on blood collected by cardiac puncture. The nadir in blood counts was observed 5 days after radiolabeled antibody injection. An absorbed dose to the marrow from the 212Bi alpha-particle emissions of 1.6 Gy yielded a marrow cellularity reduction of 50 %. The absorbed dose from XRT to achieve the same reduction in marrow cellularity was 5.7 Gy. This gives an RBE of 3.6 for a 212Pb-anti-HER2/neu antibody. Since hematologic toxicity is dose-limiting in almost all antibody-based RPT, in vivo measurements of RBE are critical to avoiding it. 2 Gy to the red marrow of low LET radiation is a threshold between low platelet toxicity grades (1 and 2) vs high (3 and 4) grade toxicity. These results suggest that the toxicity threshold for a 212Pb-antibody would be less than 1 Gy.
Citation Format: Ioanna Liatsou, Anders Josefsson, Angel Cortez, Robert F. Hobbs, Cory Brayton, Julien Torgue, George Sgouros. RBE, in vivo, for a 212Pb-conjugated anti-HER2/neu antibody [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 5350.