bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 961: TCF7 promotes a mammary cancer-stem-like phenotype leading to metastasis via potentiation of a hybrid epithelial/mesenchymal (E/M) phenotype
Authors: Liang Huizhi , Benard Outhiriaradjou , Ren Zuen , Suyama Kimita , Norton Larry , Hazan Rachel B.
Published: June 2022

Cancer stem cells (CSCs) are a minor population of carcinoma cells that can self-renew and give rise to differentiated progenitors that form the bulk of the tumor. CSCs cause tumor recurrence, chemoresistance and metastasis. The epithelial-to-mesenchymal transition (EMT) promotes tumor cell migration, invasion and cancer stem cell properties. The Wnt signaling pathway is a major driver of cancer stemness and is regulated by the TCF/LEF family of transcription factors. Using loss and gain of function of TCF7 (TCF1) in mouse and human breast cancer cells, we were able to demonstrate that TCF7 promotes cancer stemness through striking regulation of the EMT process. TCF7 knockdown in PyMT mammary tumor cells induced luminal epithelial differentiation, resulting in inhibition of oncosphere formation, migration, tumor growth and lung colonization. However, in keeping with a changing view of EMT as a strictly binary process, we found that TCF7 shifts tumor cells towards a hybrid epithelial/mesenchymal state (E/M) rather than a mesenchymal (M) state. This E/M population was shown to carry stemness and metastatic properties and to be interestingly represented by a small “stem-like” subpopulation in triple negative breast cancer (TNBC) cells. Using CD44 and CD104 (integrin β4) flow cytometry to isolate E/M cells from normal MCF10A and basal-like MDA-MB-468 breast cancer cells, we show that TCF7, Snail, and GSK3β phosphorylation were all highly enriched in this population whereas Zeb-1 (a marker of mesenchymal cells), was absent from E/M cells. These data support a model whereby TCF7 potentiates Wnt signaling which in turn activates GSK3β phosphorylation, resulting in Snail upregulation and enrichment of cells in the E/M state that is conducive of stemness and metastasis.

Citation Format: Huizhi Liang, Outhiriaradjou Benard, Zuen Ren, Kimita Suyama, Larry Norton, Rachel B. Hazan. TCF7 promotes a mammary cancer-stem-like phenotype leading to metastasis via potentiation of a hybrid epithelial/mesenchymal (E/M) phenotype [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 961.
Abstract 999: Epigenetic loss of heterogeneity from low to high grade localized prostate tumors
Authors: Eksi Ece Sebnem , Sayar Zeynep , Chitsazan Alex , Thomas George T. , Adey Andrew , Spellman Paul T. , Kopp Ryan
Published: June 2022

Identifying precise molecular subtypes attributable to specific stages of localized prostate cancer has proven difficult due to high levels of heterogeneity. Bulk assays represent a population-average, which mask the heterogeneity that exists at the single-cell level. In this work, we sequenced the accessible chromatin regions of 14,424 single-cells from 18 flash-frozen prostate tumors. We observe shared chromatin features among low-grade prostate cancer cells are lost in high-grade tumors. Despite this loss, high-grade tumors exhibit an enrichment for FOXA1, HOXB13 and CDX2 transcription factor binding sites, indicating a shared trans-regulatory program. We identify two unique genes encoding neuronal adhesion molecules that are highly accessible in high-grade prostate tumors. We show NRXN1 and NLGN1 expression in epithelial, endothelial, immune and neuronal cells in prostate cancer using cyclic immunofluorescence. Our results provide a deeper understanding of the active gene regulatory networks in primary prostate tumors, critical for molecular stratification of the disease.

Citation Format: Ece Sebnem Eksi, Zeynep Sayar, Alex Chitsazan, George T. Thomas, Andrew Adey, Paul T. Spellman, Ryan Kopp. Epigenetic loss of heterogeneity from low to high grade localized prostate 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 999.
Abstract CT166: Injection site reactions correlate to delayed type hypersensitivity tests and suggest that GP2 reverses immune suppression of trastuzumab-treated HER2 positive patients in a phase IIb study evaluating HER2/neu peptide GP2 (GLSI-100) vs. GM-CSF after adjuvant trastuzumab in HER2 positive women with breast cancer
Authors: Patel Snehal S. , McWilliams David B. , Patel Mira S. , Thompson Jaye , Daugherty F. Joseph
Published: June 2022

The authors did not submit an updated abstract. The original abstract should be considered final.

Citation Format: Snehal S. Patel, David B. McWilliams, Mira S. Patel, Jaye Thompson, F. Joseph Daugherty. Injection site reactions correlate to delayed type hypersensitivity tests and suggest that GP2 reverses immune suppression of trastuzumab-treated HER2 positive patients in a phase IIb study evaluating HER2/neu peptide GP2 (GLSI-100) vs. GM-CSF after adjuvant trastuzumab in HER2 positive women with breast cancer [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 CT166.
Abstract CT250: A first-in-human phase 1 study of NL-201 in patients with relapsed or refractory cancer
Authors: Naing Aung , Callahan Margaret , Costello Brian A. , Curti Brendan , Hall Evan , Hansen Aaron , Long Georgina V. , Joshua Anthony M. , Wetmore Cynthia , Weickhardt Andrew
Published: June 2022

Background: NL-201 is a selective and long-acting computationally designed alpha-independent agonist of the IL-2 and IL-15 receptors, which share beta and gamma signaling subunits. NL-201 is being developed as a potent activator of CD8+ T cells and NK cells for cancer immunotherapy. Binding to the beta and gamma subunits stimulates dose-dependent expansion and tumor infiltration of cytotoxic CD8+ T cells and NK cells, thereby enhancing the immune response in the tumor. The absence of binding to the IL-2 alpha subunit reduces the undesirable effects of traditional IL-2 therapies, such as vascular leak syndrome and expansion of immunosuppressive regulatory T cells. As such, NL-201 is designed to promote the desired immunomodulatory anti-tumor effects of IL-2 with an improved safety profile.

Methods: NL201-101 is a Phase 1 first-in-human, open-label, dose-escalation and cohort expansion study consisting of two parts. Part 1 is a monotherapy dose-escalation study in up to 60 adult patients with advanced and/or refractory solid tumors to define the safety profile and the recommended Phase 2 dose (RP2D) and schedule of NL-201. During dose escalation, two different schedules will be evaluated: dosing every 21 days (Schedule A), or on days 1 and 8 of each 21-day cycle (Schedule B). Tumor response will be assessed by Response Evaluation Criteria in Solid Tumours (RECIST) 1.1 and/or RECIST for use in cancer immunotherapy trials (iRECIST). In Part 2, patients with pathologically proven diagnosis of melanoma and renal cell carcinoma (up to N=30/cohort), who have advanced and/or refractory measurable disease and have failed at least one line of treatment, which may include checkpoint inhibitors, will be enrolled. Key exclusion criteria include history of brain cancer or active brain metastases, carcinomatous meningitis, neurologic autoimmune disease; patients previously receiving CAR-T or IL-2-based therapies are not eligible. Recruitment of Part 1 began in April 2021, and the trial is actively enrolling. Clinicaltrials.gov identifier: NCT04659629.

Citation Format: Aung Naing, Margaret Callahan, Brian A. Costello, Brendan Curti, Evan Hall, Aaron Hansen, Georgina V. Long, Anthony M. Joshua, Cynthia Wetmore, Andrew Weickhardt. A first-in-human phase 1 study of NL-201 in patients with relapsed or refractory cancer [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 CT250.
Abstract CT256: A pilot clinical study of VAL-413 (Orotecan®, oral irinotecan HCl) in patients with recurrent pediatric solid tumors
Authors: Geller James , Thompson Patrick , Oesterheld Javier , Brown Dennis M. , Bacha Jeffrey , Kanekal Sarath , Lopez Lorena , Leggas Markos , Sankar Neil , Yam Noymi , Wagner Lars M.
Published: June 2022

Intravenous irinotecan hydrochloride (IRN-IV) is approved for the treatment of adult colorectal cancer. IRN-IV is also widely used off-label for a range of adult and pediatric solid tumors including recurrent Ewing sarcoma, rhabdomyosarcoma, neuroblastoma, hepatoblastoma, Wilms tumor, gynecologic cancers, lung cancer and medulloblastoma. Recently, commercially available intravenous irinotecan has been administered orally (IRN-IVPO) in pediatric patients to improve convenience, reduce in-clinic time and overall cost of treatment. Unfortunately, the palatability of the intravenous preparation is poor, leading to reduced compliance especially in younger pediatric patients. Development of an advanced formulation to improve tolerability and patient compliance is an important unmet need. VAL-413 is a novel formulation developed to improve palatability of oral irinotecan. We will report on an ongoing Phase 1-2 first-in-human clinical trial of VAL-413, designed to test the hypothesis that VAL-413 improves palatability without significant pharmacokinetic differences from IRN-IVPO using intra-patient comparison of pharmacokinetic profiles. The evaluation of two dose levels will help to formally define a recommended dose for advanced clinical studies.

Trial Design: Patients ≥ 1 year of age or ≤ 30 years of age with recurrent pediatric solid tumors and adequate bone marrow, renal and liver function, for whom irinotecan therapy is a treatment option, are eligible. Up to 20 eligible patients will receive VAL-413 90mg/m2/day or 110mg/m2/day using a standard 3 + 3 design. During the first cycle of treatment, each patient will receive four daily doses of VAL-413 and one daily dose of IRN-IVPO, together with five (5) days of concurrent temozolomide. Pharmacokinetic assessments will follow both VAL-413 and IRN-IVPO administration using a limited sampling strategy. During all subsequent cycles, only VAL-413 will be given with temozolomide in 5-day courses administered every 21 days. Up to 17 cycles of treatment may be administered on this study.

Outcome Measures: Toxicity is assessed by NCI CCTCAEv5; tumor response is assessed by RECIST 1.1. A palatability survey instrument will assess palatability of VAL-413 vs. IRN-IVPO; and comparative intrapatient pharmacokinetics of irinotecan and its metabolites will be assessed in all patients.

Citation Format: James Geller, Patrick Thompson, Javier Oesterheld, Dennis M. Brown, Jeffrey Bacha, Sarath Kanekal, Lorena Lopez, Markos Leggas, Neil Sankar, Noymi Yam, Lars M. Wagner. A pilot clinical study of VAL-413 (Orotecan®, oral irinotecan HCl) in patients with recurrent pediatric solid 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 CT256.
Abstract CT567: Comprehensive measures of COVID-19 vaccine efficacy in adolescent cancer patients: Results from SerOzNET
Authors: Segelov Eva , Body Amy , Turville Stuart , Smith Corey , Lineburg Katie , Rao Sudha , McCuaig Robert , Opat Stephen , Niang Zin , Lal Luxi , Luong Vi , Abdulla Hesham , Lopez Veronica Aedo , Padhye Bhavna , Bolanos Noemi Fuentes , Anazodo Antoinette , MacIntyre Raina , Downie Peter , O'Brien Tracey , Ahern Elizabeth
Published: June 2022

The authors did not submit an updated abstract. The original abstract should be considered final.

Citation Format: Eva Segelov, Amy Body, Stuart Turville, Corey Smith, Katie Lineburg, Sudha Rao, Robert McCuaig, Stephen Opat, Zin Niang, Luxi Lal, Vi Luong, Hesham Abdulla, Veronica Aedo Lopez, Bhavna Padhye, Noemi Fuentes Bolanos, Antoinette Anazodo, Raina MacIntyre, Peter Downie, Tracey O'Brien, Elizabeth Ahern. Comprehensive measures of COVID-19 vaccine efficacy in adolescent cancer patients: Results from SerOzNET [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 CT567.
Abstract LB015: CCR7-expressing T-cell acute lymphoblastic leukemia mouse model provides a platform for developing novel anti-CCR7 therapies to prevent CNS invasion
Authors: Torres Angel , Vazquez Aaron , Glenn Sean , Fuentes Zenaida , Chacon jessica , Bill Colin , Vines Charlotte M.
Published: June 2022

C-C chemokine receptor 7 (CCR7) plays a pivotal role in promoting the migration of T-cell acute lymphoblastic leukemia (T-ALL) cells into the central nervous system during leukemogenesis. Overexpression of CCR7 has also been linked to developing central nervous system (CNS) lymphoma. CCR7 and its ligand, CCL19 are important mediators in the development of these cancers. Thus there is an urgent need for a translational syngeneic CCR7-expressing T-ALL model that can speed up the discovery of drugs that can be used to block CCR7 function during the progression of T-ALL. Using the established ROSA26 floxed-stop Prdm14 (R26PR)/Mx-1 Cre mouse T-ALL model we have initiated studies using a CCR7/CCL19 antagonist, ELC8-83 to examine the molecular mechanisms that mediate CCR7-directed migration to, invasion of, proliferation within and exit from the CNS. mRNA expression of CCR7 in the T-ALL was confirmed by RT-PCR and protein expression on the cell surface was confirmed by flow cytometry. Chemotaxis and calcium mobilization of T-ALL in response to CCL19 was confirmed using transwell-migration assays and FURA-4. ELC8-83 was used to block this signaling. These studies demonstrate the efficacy of ELC8-83 in blocking signaling in T-ALL and provide a platform for testing ELC8-83 in the mouse model of T-ALL.

Citation Format: Angel Torres, Aaron Vazquez, Sean Glenn, Zenaida Fuentes, jessica Chacon, Colin Bill, Charlotte M. Vines. CCR7-expressing T-cell acute lymphoblastic leukemia mouse model provides a platform for developing novel anti-CCR7 therapies to prevent CNS invasion [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 LB015.
Abstract LB037: Chromatin modifications guide Pax5 dependent gene expression in NE like prostate cancer
Authors: Bhattacharya Sreyashi , Islam Ridwan , Bodas Sanika , Mishra Juhi , Das Dipanwita , Datta Kaustubh , Dutta Samikshan
Published: June 2022

Background: Prolonged ablation of androgen receptor pathway in prostate cancer leads to the emergence of therapy resistant neuroendocrine-like (NE-like) aggressive lineage. This NE development is associated with chromatin reprogramming underlying epigenetic alterations and changes in transcriptional network. Clinically, NE development follows a poorer progression with multifaceted therapeutic challenges. Current lack of effective understanding of this NE trans-differentiation process limits the stratification of therapeutic window with further worsened patient management. The following study aims to identify the sequential molecular players responsible for therapy resistant NE like development.

Objective: The primary objective of this study is to understand how chromatin modifications along with epigenetic regulation dictates the establishment of NE trans-differentiation process in Prostate Cancer in response to Androgen Receptor blockade therapy.

Methods: We generated various NE-like cell lines either by genetic modification or therapeutic selection. We performed RNA Seq, ATAC Seq and acetylated Histone (H3K18 and H3K27) ChIP Seq in our developed NE and adenocarcinoma cell lines. We next compared ATAC Seq and Acetylated histone ChIP Seq with RNA Seq in C4-2B and C4-2BER.

Results: Our ATAC Seq and acetylated histone footprints (Ac H3K18 and Ac H3K27 ChIP Seq) analyses revealed an enhanced chromatin accessibility during adenocarcinoma to NE transformation. Overlapping RNA seq results further suggested newly transcribed neuronal genes with higher degrees of promoter accessibility. Transcription Factor scanning analysis among newly active gene promoters revealed preferential binding of Pax5, whose expression has been validated to be selectively occurring in NE lineage unlike adenocarcinoma. Further analysis of Pax5 promoter site suggested that changes in 5-hydroxymethylation pattern during adenocarcinoma to NE transformation guided the recruitment of PBX1 at Pax5 promoter. Validating NE patient expression in silico supported that PBX1/Pax5 expressions are selective in NE lineage development.

Conclusions: Our study concludes that specific chromatin alterations guide the recruitment of PBX1 to upregulate Pax5 to maintain a therapy resistant neuronal surrounding in NE-like prostate cancer development.

Citation Format: Sreyashi Bhattacharya, Ridwan Islam, Sanika Bodas, Juhi Mishra, Dipanwita Das, Kaustubh Datta, Samikshan Dutta. Chromatin modifications guide Pax5 dependent gene expression in NE like prostate cancer [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 LB037.
Abstract LB043: Identification and characterization of cancer-associated fibroblast subpopulations in lung adenocarcinoma
Authors: Kim Daeseung , Kim Jeong Seon , Kim Seoree , Chun Sang Hoon , Kim Jae Jun , Cheon Inyoung , Lee Sieun , Yoon Jung Sook , Hong Soon Auck , Won Hye Sung , Kang Keunsoo , Ahn Young-Ho , Ko Yoon Ho
Published: June 2022

Background: Cancer-associated fibroblasts (CAFs) reside within the tumor microenvironment, facilitating cancer progression and metastasis via direct and indirect interactions with cancer cells as well as other stromal cell types. CAFs are comprised of heterogeneous subpopulations of activated fibroblasts, including myofibroblastic, inflammatory, or immunosuppressive CAFs. In this study, we sought to identify subpopulations of CAFs isolated from human lung adenocarcinomas and describe their transcriptomic as well as functional characteristics through single-cell RNA sequencing (scRNA-seq) and subsequent bioinformatics analyses.

Methods: We isolated and cultured two types of CAFs. Total CAFs were isolated after negative selection using cell-type-specific antibodies against lymphocytes (CD45), macrophages (CD68), endothelial cells (CD31), and epithelial cells (Ep-CAM). THY1+ CAFs were isolated after additional selection based on CAF-specific marker THY1. Total CAFs (n=5,139 cells) and THY1+ CAFs (n=4,038 cells) were subjected to 10X Genomics scRNA-seq. scRNA-seq data were then integrated and analyzed using the Seurat method.

Results: Cell trajectory analysis of combined total and THY1+ CAFs revealed two branching points with five distinct branches. Based on Gene Ontology analysis, we denoted Branch 1 as “immunosuppressive”, Branch 2 as “neoantigen-presenting”, Branch 4 as “myofibroblastic”, and Branch 5 as “proliferative” CAFs. We selected representative branch-specific markers and measured their expression levels in total and THY1+ CAFs. We also investigated the effects of these markers on CAF activity under co-culture with lung cancer cells.

Conclusions: This study describes novel subpopulations of CAFs in lung adenocarcinoma, highlighting their potential value as therapeutic targets.

Citation Format: Daeseung Kim, Jeong Seon Kim, Seoree Kim, Sang Hoon Chun, Jae Jun Kim, Inyoung Cheon, Sieun Lee, Jung Sook Yoon, Soon Auck Hong, Hye Sung Won, Keunsoo Kang, Young-Ho Ahn, Yoon Ho Ko. Identification and characterization of cancer-associated fibroblast subpopulations in lung adenocarcinoma [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 LB043.
Abstract LB049: Spatial immune determinants of ICB response in STK11-mutated non-small cell lung cancer
Authors: Uhlitz Florian , Linn Douglas , Krall Elsa Beyer , Egger Jacklynn , Rizvi Hira , Chang Jason , Nicholson Benjamin , Vanguri Rami , Chow Andrew , Hellmann Matthew , Shah Sohrab
Published: June 2022

Response to immune checkpoint blockade (ICB) in non-small cell lung cancers (NSCLC) is associated with recurring mutations in tumor suppressor genes STK11 and TP53. Whereas STK11-mutated patients are mostly insensitive, TP53-mutated patients commonly respond to ICB. Previous studies have linked mutational status in these genes to differences in cell type composition of the tumor microenvironment (TME). However, it remains unclear if differences in cell type compositions as well as cell-cell interactions in turn could account for the observed differences in treatment response and overall survival in NSCLC. Here, we perform spatial profiling of immune and stromal phenotypes in the TME of 119 NSCLC patients using imaging mass cytometry (IMC) on tissue microarrays (TMA). Matching data from MSK IMPACT (clinical sequencing) was used to establish mutation profiles and therapeutic response was included in the analysis. We find that STK11-mutated NSCLC is characterized by decreased CD4 T cell and increased neutrophil abundance, while TP53-mutated NSCLC is associated with increased CD8 T cell and decreased endothelial cell abundance. Accordingly, we stratified the patient population into TME classes by cell type composition. We found that while mutational status does not inform overall survival in our cohort, stratification by cell type abundance strongly associates with patient outcome (p-value: 0.000146, logRank test). Patients with neutrophil-rich TMEs show worse overall survival (25% 5-year survival), while patients with increased endothelial cell and macrophage abundance have a tendency to live longer (80% and 75% 5-year survival respectively). Furthermore, we interrogate pairwise proximity of immune cell types and states to construct cellular networks in NSCLC. Together, our findings suggest that TME cell type composition and cellular networks are potential molecular determinants for ICB therapeutic response in NSCLC patients.

Citation Format: Florian Uhlitz, Douglas Linn, Elsa Beyer Krall, Jacklynn Egger, Hira Rizvi, Jason Chang, Benjamin Nicholson, Rami Vanguri, Andrew Chow, Matthew Hellmann, Sohrab Shah. Spatial immune determinants of ICB response in STK11-mutated non-small cell lung cancer [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 LB049.
Abstract LB066: Targeting low density lipoprotein receptors in the pancreatic adenocarcinoma
Authors: Flores Leo , Qu Xuewei , Malicet Cedric , Lecorche Pascaline , Delpassand Ebrahim , Temsamani Jamal , Tworowska Izabela
Published: June 2022

Introduction: Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive malignancy with a poor 5-year overall survival rate at all stages of disease (7-10%). The immunohistochemistry of pancreatic cancer tissue has shown a significantly higher level of positive LDLR (low-density lipoprotein receptor) staining in primary tumors compared to the normal adjacent pancreas. LDLR is overexpressed in the epithelial pancreatic adenocarcinoma, irrespectively of tumor size, stage, and aggressiveness. The objective of this study was to determine the LDLR-targeting properties of 68Ga-labeled peptide conjugate, 68Ga-RMX-VH, in pancreatic adenocarcinoma cell lines.

Methods: RMX-VH peptide conjugate (25-50μg) was labeled with 68Ga (50-100mCi, ITM Germany) in mild conditions in the presence of scavenger, sodium ascorbate (8mg/ml). The cellular uptake and competition studies of the radiotracer (15μCi/well) were completed in multiple pancreatic adenocarcinoma cell lines and in vivo in PDAC xenografts generated in athymic nude mice. The PET/CT images were acquired using a G4 PET/X-ray camera (Sofie Biosciences; 10min/scan) at 1h, 2h post-injection. This study determined in vivo and in vitro time-dependent accumulation of this agent in LDLR-overexpressing pancreatic adenocarcinoma cells.

Results: 68Ga-RMX-VH was synthesized with higher than 95% radiochemical purity. The radiotracer was incubated in pancreatic adenocarcinoma cell lines for 1h and has shown the highest uptake in HPAF-II (6.7%ID/mg) and BxPC-3 (5.3 %ID/mg) and MiaPaCa2 (4.75 %ID/mg), respectively. Western blot showed a variable level of LDLR overexpression in human pancreatic cancer cells. The microPET imaging studies confirmed rapid accumulation and retention of radiotracer in the tumor (1.18 %ID/g) and elimination through kidneys (4.5 %ID/g) and bladder (SUV ratio of tumor to kidneys: 0.21). These results correlate with previously reported retention of the agent in Pk4a pancreatic adenocarcinoma.

Conclusions: RMX-VH has the potential to evaluate the role of LDL receptors in pancreatic adenocarcinoma. We have initiated the exploratory clinical study of this agent in LDLR-overexpressing solid tumors, including pancreatic adenocarcinoma.

Citation Format: Leo Flores, Xuewei Qu, Cedric Malicet, Pascaline Lecorche, Ebrahim Delpassand, Jamal Temsamani, Izabela Tworowska. Targeting low density lipoprotein receptors in the pancreatic adenocarcinoma [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 LB066.
Abstract LB150: Clinical outcome prediction of prostate cancer using machine learning based on fusion gene detection
Authors: Luo Jian-Hua , Liu Silvia , Yu Yan-Ping
Published: June 2022

Prediction of the clinical outcomes of prostate cancer remains a challenge. Recently, we discovered a panel of 8 fusion genes that occurred in aggressive prostate cancer. In order to make the fusion gene test clinically ready as a predictor, we have modified to test into a semi-quantitative Taqman QRT-PCR. In the funding period, Two hundred seventy-one prostate cancer samples with clinical follow-up were collected from University of Pittsburgh Medical Center. In addition, 194 prostate cancer samples from University of Wisconsin, Madison and 108 prostate cancer samples from Stanford University were collected. Taqman QRT-PCRs were performed on these samples. Significant numbers of samples were found positive for some of these fusion genes. The expression of MAN2A1-FER, SLC45A2-AMACR, MTOR-TP53BP1 fusions are associated with prostate cancer recurrence in the UPMC cohort. Cross-validation showed that fusion gene model predicts up to 91% clinical outcomes of prostate cancer accurately. When cohorts of UPMC, Stanford and Wisconsin were combined, the accuracy is 74%. The combination of fusion with Gleason appeared to improve the overall accuracy from 77% (Gleason) to 92% (Gleason+fusion) in the UPMC cohort, and from 71% (Gleason) to 82% (Gleason+fusion) when all three cohorts are combined. When fusion combined with both pathology stage and Gleason, the accuracy was improved a little further: 93% accuracy in the UPMC cohort and 83% when all three cohorts are combined. In summary, fusion transcript prediction model may have a role in prostate cancer prognosis prediction and guiding the management of prostate cancer patients.

Citation Format: Jian-Hua Luo, Silvia Liu, Yan-Ping Yu. Clinical outcome prediction of prostate cancer using machine learning based on fusion gene detection [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 LB150.
Abstract LB505: Design and discovery of MRTX0902, a potent, selective, and orally bioavailable SOS1 inhibitor
Authors: Ketcham John M. , Briere David M. , Burns Aaron C. , Christensen James G. , Gunn Robin J. , Haling Jacob , Ivetac Anthony , Khare Shilpi , Kuehler Jon , Kulyk Svitlana , Laguer Jade , Lawson John D. , Moya Krystal , Nguyen Natalie , Olson Peter , Rahbaek Lisa , Smith Christopher R. , Sudhakar Niranjan , Thomas Nicole C. , Vanderpool Darin , Wang Xiaolun , Marx Matthew A.
Published: June 2022

KRAS mutations are the most common activating mutations in human cancer that ultimately lead to hyperactivation of the MAPK pathway and uncontrolled growth. KRAS functions as a small GTPase that cycles through its GTP-loaded “on” state and its GDP-loaded “off” state, a highly regulated process that is crucial for normal cell proliferation and survival. The guanine nucleotide exchange factor (GEF) SOS1 plays a critical role in this process by regulating the “on/off” state of KRAS. The protein-protein interaction between SOS1 and KRAS facilitates turnover of KRAS from the GDP-loaded inactive state to its activated and GTP-loaded state, a critical step to enable productive KRAS effector binding and activation of downstream signaling. The KRASG12C inhibitor, adagrasib (MRTX849), irreversibly binds to the GDP-loaded inactive conformation of KRASG12C and has recently shown encouraging clinical activity across several cancer types. As adagrasib binds preferentially to the inactive state of KRAS, blockade of SOS1 is anticipated to shift KRASG12C into the adagrasib-susceptible GDP-loaded state. Furthermore, this combination strategy could be used to target other mutant-driven cancers within the MAPK pathway using the appropriate KRASmut inhibitors and/or inhibitors of other targets within the MAPK pathway including MEK or EGFR. MRTX0902 was identified using iterative structure-based design as a selective inhibitor of SOS1 that demonstrates an IC50 value of 2 nM in a SOS1 HTRF binding assay and 30 nM in an MKN1 cellular assay. In pharmacokinetic evaluation across species, MRTX0902 demonstrated low extraction ratios and moderate to high bioavailability in mice, rats, and dogs. In preclinical models, MRTX0902 augmented the antitumor activity of adagrasib and other selected therapies. The design, discovery, and preclinical characterization of the potential best-in-class candidate MRTX0902 will be described.

Citation Format: John M. Ketcham, David M. Briere, Aaron C. Burns, James G. Christensen, Robin J. Gunn, Jacob Haling, Anthony Ivetac, Shilpi Khare, Jon Kuehler, Svitlana Kulyk, Jade Laguer, John D. Lawson, Krystal Moya, Natalie Nguyen, Peter Olson, Lisa Rahbaek, Christopher R. Smith, Niranjan Sudhakar, Nicole C. Thomas, Darin Vanderpool, Xiaolun Wang, Matthew A. Marx. Design and discovery of MRTX0902, a potent, selective, and orally bioavailable SOS1 inhibitor [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 LB505.
Abstract LB516: MDM2/MDM4 amplification and CDKN2A deletion in melanoma brain metastases and GBM may have implications for targeted therapeutics and immunotherapy
Authors: Arnoff Taylor E. , El-Deiry Wafik S.
Published: June 2022

Melanoma has a five-year survival rate of 27% for distant metastatic disease, and there remains a paucity of targeted therapies for metastatic disease and biomarkers that predict metastasis to specific sites. We analyzed 1081 primary melanoma samples and 358 metastatic melanoma samples and found that metastatic disease is enriched for amplifications in both MDM2 and MDM4 compared to primary disease, and these amplifications are associated with a lower probability of overall survival. Two additional negative regulators of TP53, namely USP7 and PPM1D, are enriched for alterations in metastatic melanoma compared to primary melanoma. MDM4 amplifications are associated with a higher rate of metastasis to the brain, liver, and lungs, while MDM2 amplifications are associated with a higher rate of metastasis to the brain, liver, and adrenal glands. These findings suggest that patients with metastatic melanoma show an enhanced dysregulation of the TP53 pathway compared to primary disease; though still under ongoing preclinical evaluation to assess therapeutic implications, we propose that patients with metastatic melanoma and TP53 wild-type status may be more likely to benefit from MDM2, MDM4, USP7, and PPM1D inhibitors, both alone and in combination, compared to those with primary disease. Additionally, we found that patients with MDM2 alterations were more likely to have a deep deletion in CDKN2A, alterations that are also associated with a higher rate of metastasis to the brain. We found that patients with a CDKN2A deep deletion had a statistically significant higher rate of alterations in TTN, MUC16, LRP1B, NF1, and SERPINB4, alterations that have all been previously associated with a favorable response to immune checkpoint inhibitors in melanoma. We therefore propose that CDKN2A deletion may serve as a biomarker to predict response to immunotherapy in melanoma. Moreover, given prior documented cases of patients diagnosed with both melanoma and glioblastoma multiforme (GBM), we found that GBM displays the highest rate of deep deletions in CDKN2A (54.39%) across all cancer types screened. We analyzed 619 GBM samples and found that 9.16% display an MDM2 amplification and 9.52% display an MDM4 amplification. Given the genomic similarities between melanoma and glioblastoma, we suggest that patients with melanoma or GBM and amplifications in MDM2/4 and CDKN2A deletions may need the development of combinations of targeted inhibitors of MDM2/4, CDK’s and immunotherapy. We are currently pursuing these translational directions.

Citation Format: Taylor E. Arnoff, Wafik S. El-Deiry. MDM2/MDM4 amplification and CDKN2A deletion in melanoma brain metastases and GBM may have implications for targeted therapeutics and immunotherapy [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 LB516.
Abstract LB520: A pharmacodynamic platform using liquid biopsy to support dose selection for the ATR inhibitor ART0380 (IACS-030380)
Authors: Patel Manish , Moore Kathleen N. , Piscitello Desiree , Majithiya Jayesh , Luzarraga Marina Roy , Millward Helen , Holt Sarah V. , Johnson Melissa
Published: June 2022

Inhibition of ataxia telangiectasia and Rad-3 related (ATR) kinase offers therapeutic promise for DNA damage response deficient tumors. In addition, ATR inhibitors may offer even broader clinical utility when combined with PARPi’s, chemo, immune or radiation therapy. Flat-fixed dosing of ATR inhibitors alone or in combination has provided clinical benefit but is associated with on target, dose limiting haematological toxicity. Strategies to refine dose selection of this class of medicine may further optimize clinical benefit. The aim of our ongoing investigation is to determine if the dose selection for clinical development of the novel ATR inhibitor ART0380 (IACS-030380) may be optimized based on the degree of PD engagement in both tumor and normal tissue from patients. To do this, we have utilized in vitro and in vivo cancer models to help us understand the dynamic and temporal response to several biomarkers of ATR inhibition and DNA damage. Once established in vitro, we selected key markers, such as γH2AX and pKAP1, to explore in vivo using doses predicted to be biologically effective in man and have shown that these are modulated following exposure to ART0380. To enable the serial assessment of PD engagement in both tumor and normal tissue, we have developed an assay in the phase 1 study of ART0380 (NCT04657068) to measure γH2AX levels in circulating tumor cells (CTC’s) and normal cells (PBMC’s). A significant advantage of this approach is that samples are taken from the same blood draw and at several timepoints following exposure to ART0380. So far, our studies have shown that in patients, who have experienced drug exposures predicted to be biologically effective, γH2AX levels in CTC’s increase by up to 20% respectively from baseline while γH2AX in PBMC’s remains unaffected. This observation may highlight that target engagement has taken place for ART0380 in the tumor without an effect in normal tissue, a phenomena perhaps explained by the pharmacokinetic profile of ART0380. The clinical study is ongoing and we continue to monitor individual patient responses, toxicity, and correlate with PD engagement in tumor and normal tissue circulating biopsies. In addition, we are now expanding our analysis into a multiplexed assay where we will measure pKAP1 as well as γH2AX to build a more detailed assessment of PD activity in patients. Updated data will be presented.

Citation Format: Manish Patel, Kathleen N. Moore, Desiree Piscitello, Jayesh Majithiya, Marina Roy Luzarraga, Helen Millward, Sarah V. Holt, Melissa Johnson. A pharmacodynamic platform using liquid biopsy to support dose selection for the ATR inhibitor ART0380 (IACS-030380) [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 LB520.
Abstract LB525: Discovery and characterization of ABSK111, a selective, CNS-penetrable, and broad-spectrum EGFR inhibitor targeting exon20 insertion, atypical and extracellular mutations
Authors: Dai Cheng , Peng Juan , Yang Fei , Deng Haibing , Zhao Yuan , Yu Hongping , Xu Yaochang , Chen Zhui , Yang Shuqun
Published: June 2022

Epidermal growth factor receptor (EGFR) exon20 insertion mutations and atypical mutations account for about 9% and 20% of EGFR-mutated non-small cell lung cancer (NSCLC), respectively. Currently approved EGFR tyrosine kinase inhibitors (TKIs) have shown efficacy in NSCLC patients with exon20 insertion and atypical mutations, but with limited overall response and high rate of EGFR-related severe adverse events. This may be associated with the inhibition of wild-type (WT) EGFR. ABSK111 is a highly potent, selective, and CNS-penetrable EGFR inhibitor, targeting multiple EGFR and HER2 mutations, including exon20 insertion, atypical, and extracellular mutations. Here we describe the preclinical in vitro and in vivo characterization of ABSK111. ABSK111 potently inhibited the proliferation of BA/F3 cell lines harboring EGFR exon20, atypical and extracellular mutations with higher selectivity for WT EGFR than currently approved EGFR TKIs. ABSK111 also suppressed HER2 atypical and exon20 mutations. Further, ABSK111 potently blocked the phosphorylation of EGFR exon20 insertion mutations and EGFR variant III in BA/F3 cell lines, with less inhibition of WT EGFR signal than the approved TKIs. Moreover, pharmacokinetic and pharmacodynamic studies demonstrated sustained and exposure-dependent suppression of p-ERK in tumor tissue following a single oral dose of ABSK111. Finally, ABSK111 showed dose-dependent anti-tumor activity in BA/F3 tumor models with EGFR exon20 insertion mutations and EGFR variant III without significant body weight loss. Pharmacodynamic analysis of endpoint samples from efficacy study showed sustained inhibition of p-ERK, which was superior to the approved exon20 insertion inhibitor mobocertinib. Taken together, these results demonstrate the ability of ABSK111 to inhibit a broad spectrum of EGFR and HER2 mutations, including exon20 insertions, atypical and extracellular mutations, while sparing the WT form of EGFR. In addition to the application in NSCLC, the activity against EGFR extracellular mutations and the ability to penetrate into brain suggest the application of ABSK111 in glioblastoma multiforme (GBM).

Citation Format: Cheng Dai, Juan Peng, Fei Yang, Haibing Deng, Yuan Zhao, Hongping Yu, Yaochang Xu, Zhui Chen, Shuqun Yang. Discovery and characterization of ABSK111, a selective, CNS-penetrable, and broad-spectrum EGFR inhibitor targeting exon20 insertion, atypical and extracellular mutations [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 LB525.
Abstract LB529: Oncogenic KRas plays a significant role in regulating expression of IDO1
Authors: Lee Eunji , He Felicia , Choi Byeong Hyeok , Dai Wei
Published: June 2022

Ras proteins are among the most widely studied proto-oncogene products. Ras proteins are membrane-anchored GTPases that participate in multiple signaling cascades regulating crucial cellular processes including cell survival, proliferation, and differentiation. Ras mutations and/or deregulated Ras activities frequently lead to inflammation and malignant transformation. Recent studies have also shown that Ras mutations are associated with immuno-resistance by positive regulation of PD-L1 expression. Indoleamine 2,3-dioxygenases 1 (IDO1) is a heme-containing enzyme that catalyzes the rate limiting step of conversion of tryptophan into kynurenine (Kyn). Extensive research in the past has shown that IDO1 and its catalytic product Kyn mediate immune tolerance, thus promoting tumorigenesis in vivo. IDO1 expression is activated by immune cytokines including interferon-γ (IFN-γ)and interleukin-6 (IL-6). However, whether there is a mechanistic link between oncogenic KRas and IDO1 expression and how IDO1 expression contributes to immune invasion of transformed cells with KRas mutations remain unclear. Here we report that oncogenic KRas significantly enhanced IFN-γ-induced IDO1 expression. In H358 lung carcinoma cells, IDO1 expression induced by IFN-γ was at least in part dependent on ERK activation, and treatment with ARS-1620, a covalent KRasG12C inhibitor, suppressed IDO1 expression induced by IFN-γ in a concentration-dependent manner. IDO1 expression was also induced by IFN-γ in HCT116 colon carcinoma cells that harbored a KRasG12D mutant allele, but not in HCT116 cells with wild-type KRas, suggesting that IFN-γ induced IDO1 expression requires Ras activation. In addition, KRas downregulation by specific siRNAs decreased IFN-γ-induced IDO1 expression in A549 lung cancer cells. Taken together, our study strongly suggests that Ras/ERK signaling pathway plays an important role in promoting IDO1 expression induced by IFN-γ.

Citation Format: Eunji Lee, Felicia He, Byeong Hyeok Choi, Wei Dai. Oncogenic KRas plays a significant role in regulating expression of IDO1 [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 LB529.
Abstract LB534: Development of GB2101, a novel anti-CCR8 antibody for cancer treatment
Authors: Du Qinglin , Cao Yiqi , Yang Xueyan , Lu Jing , Peng Fei , Zhou Wenming , Liang Liwen , Li James , Han Shuhua
Published: June 2022

Background: Regulatory T cells (Tregs) play a crucial role in suppressing immune response and maintaining hemostasis and immune tolerance. Tregs are enriched in the tumor microenvironment (TME) and suppress anti-tumor immunity. Therefore, specific depletion of Tregs in the TME is expected to reduce anti-tumor immune suppression without affecting hemostasis in the periphery. The C-C motif chemokine receptor 8 (CCR8), highly expressed on Tregs from TME but significantly lower expressed on Tregs from peripheral blood, provides an ideal target for preferentially deletion of Tregs within tumors. GB2101 is a novel anti-CCR8 monoclonal antibody generated from hybridoma. The data from in vitro and in vivo studies indicated that GB2101 is a good PCC molecule with great potential for clinical development.

Methods: GB2101 was generated by immunization of CCR8 gene plus CCR8 over-expressing cells in mice followed by hybridoma technology. The binding of the antibody to CCR8-expressing cells was detected by flow cytometry. CCL1 ligand blocking was assessed by flow cytometry and calcium flux assay. Antibody-dependent cell-mediated cytotoxicity (ADCC) function was evaluated by Jurkat-CD16A-NFAT reporter system. In vivo anti-tumor efficacy was assessed in syngeneic model using human CCR8 knock-in mice.

Results: GB2101 displayed potent binding to cells expressing CCR8. GB2101 efficiently blocked CCL1 binding and CCL1-induced signals in CCR8 expressing cells. ADCC activity against target cells was observed and afucosylated version of GB2101 improved ADCC response. GB2101 significantly inhibited tumor growth in syngeneic model.

Conclusions: GB2101 is a novel monoclonal antibody specifically binding to CCR8 with high affinity, and efficiently blocked CCL1-CCR8 pathway and suppressed tumor growth in vivo. Therefore, it is a very promising preclinical candidate that may be used in the treatment of multiple tumor types.

Citation Format: Qinglin Du, Yiqi Cao, Xueyan Yang, Jing Lu, Fei Peng, Wenming Zhou, Liwen Liang, James Li, Shuhua Han. Development of GB2101, a novel anti-CCR8 antibody for cancer treatment [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 LB534.
Abstract LE03-01: Functional and computational approaches to uncover selection advantages of cancer aneuploidy
Authors: Taylor Alison Marie
Published: June 2022

Aneuploidy, including the gain or loss of whole chromosomes or chromosome arms, is a near-universal feature of cancer. We previously applied methods that define chromosome arm aneuploidy to over 10,000 tumors in the Cancer Genome Atlas (TCGA). Cancer subtypes are often characterized by tumor specific patterns of chromosome arm copy number alterations and breakpoints; for example, squamous cell carcinomas (SCCs) from different tissues of origin are characterized by chromosome 3p (chr3p) loss and chromosome 3q (chr3q) gain. From the TCGA aneuploidy data, we developed an algorithm called BISCUT to distinguish peak regions of aneuploidy breakpoints on each chromosome arm. BISCUT identified loci affected by broad copy number alterations that provide fitness advantages or disadvantages both within individual cancer types and across cancers. Our analyses are consistent with selection being the primary driver of aneuploidy events in cancer. Recent advances in genome engineering allow generation of large chromosomal alterations and validation of findings from patient genomic data. We used the CRISPR-Cas9 system to delete one copy of chr3p in a human immortalized lung epithelial cell line similar to the putative cell-of-origin in lung SCC. Consistent with patient data, expression of chr3p genes was decreased upon deletion, as well as increased expression of interferon response genes. Cells with chr3p deletion initially proliferated more slowly than their siblings. Interestingly, after several passages in culture, this proliferation defect was rescued in chr3p deleted cells. Genome sequencing and karyotype analyses suggested that this was partially the result of chr3 duplication, with cells transitioning to a state of chr3q gain. Isolated cells with chr3q gain show deficiencies in squamous differentiation in organoid culture. Our genome engineering approach to model chromosome arm aneuploidies provides a robust model that will address a gap in our understanding of aneuploidy in cancer.

Citation Format: Alison Marie Taylor. Functional and computational approaches to uncover selection advantages of cancer aneuploidy [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 LE03-01.