bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 3992: Elucidating reciprocal interactions between bone marrow stromal cells and a novel γδ CAR T cell therapy in the context of bone metastatic prostate cancer
Authors: Frieling Jeremy S. , Bustos Xiomar , Bishop Ryan T. , Tordesillas Leticia , Abate-Daga Daniel , Lynch Conor C.
Published: April 2023

Bone metastatic castrate resistant prostate cancer (CRPC) generates tumors hallmarked by extensive bone formation due to enhanced mesenchymal stem cell (MSC)-osteoblast differentiation. These lesions are at present incurable and substantially diminish patient quality of life, but exciting preclinical studies by our group have shown that these metastases are highly sensitive to gamma delta (γδ) T cell-based CAR-T therapies. However, the impacts of CAR-T cell therapies on the bone microenvironment are presently unknown. Because MSCs are an important stromal component of the cancer-bone microenvironment with emerging immunoregulatory activities, we have recently focused on characterizing the interactions between γδ CAR-T cells and the MSC compartment and their implications for bone metastatic CRPC. Our data show that: 1) γδ CAR-T cells or conditioned media (CM) did not significantly alter MSC viability, 2) MSCs were robustly chemotactic to CM derived from tumor-activated γδ CAR-T cells, 3) MSCs treated with tumor-activated γδ CAR-T CM showed a significant induction of ICAM-1 (9.12-fold, P=0.00640) compared to controls, 4) ICAM-1 silencing significantly reduced γδ CAR-T educated MSC migratory ability, 5) tumor-activated γδ CAR-T CM differentially regulated key genes involved in MSC-osteoblast differentiation, a finding supported by Alizarin red S staining and alkaline phosphatase functional assays, and 6) tri-cultures of MSCs, CRPC cells, and γδ CAR-T cells demonstrate that MSCs significantly enhanced γδ CAR-T mediated CRPC killing. Taken together, we have shown that γδ CAR-T cells promote MSC recruitment in an ICAM-1 dependent manner, and MSCs enhance γδ CAR-T targeted CRPC killing. Reciprocally, γδ CAR-T can promote MSC commitment to osteoblast lineage without impacting their viability. These data are the first to interrogate how bone stromal components regulate γδ CAR-T mediated killing in the context of bone metastatic CRPC. We are currently investigating the mechanisms underpinning the bi-directional interplay between these cell populations.

Citation Format: Jeremy S. Frieling, Xiomar Bustos, Ryan T. Bishop, Leticia Tordesillas, Daniel Abate-Daga, Conor C. Lynch. Elucidating reciprocal interactions between bone marrow stromal cells and a novel γδ CAR T cell therapy in the context of bone metastatic prostate cancer. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3992.
Abstract 4035: Preclinical activity of BAY 2927088 in HER2 mutant non-small cell lung cancer
Authors: Siegel Franziska , Karsli-Uzunbas Gizem , Kotynkova Kristyna , McVeigh Quinn , Siegel Stephan , Korr Daniel , Schulze Volker , Berger Markus , Beckmann Georg , Cherniack Andrew , Meyerson Matthew , Greulich Heidi
Published: April 2023

HER2 mutations are potent oncogenic drivers in various cancer indications. In NSCLC, about 2% of patients carry either a HER2 exon20 insertion mutation or a HER2 point mutation. With the recent approval of fam-trastuzumab deruxtecan-nxki, the first targeted treatment option became available for HER2 mutant NSCLC patients. However, there remains a high unmet need for more effective and better tolerated therapies with the potential to improve response rates and response durability.

BAY 2927088 is a reversible small molecule inhibitor that is currently being evaluated in a first-in-human, phase I clinical trial in patients with EGFR mutant NSCLC (NCT05099172).

Here, we present the preclinical activity profile of BAY 2927088 in HER2 mutant NSCLC. BAY 2927088 shows strong antiproliferative activity in an isogenic Ba/F3 cell line panel of HER2 exon20 insertion mutations as well as HER2 point mutations. BAY 2927088 is highly potent on the most frequent HER2 exon20 insertion mutations A775insYVMA and G776del insVC, as well as in the HER2 point mutations S310F, S335C, and L755S, among others. In addition, the compound was active in a subset of endogenously HER2 mutant cancer cell lines. The in vitro activity of BAY 2927088 was validated in vivo in a patient-derived xenograft model carrying the HER2 exon20 insertion mutation A775insYVMA.

The strong preclinical activity of BAY 2927088 in HER2 mutant NSCLC supports clinical evaluation in this indication and might offer a novel targeted therapy option for NSCLC patients that carry HER2 mutations.

Citation Format: Franziska Siegel, Gizem Karsli-Uzunbas, Kristyna Kotynkova, Quinn McVeigh, Stephan Siegel, Daniel Korr, Volker Schulze, Markus Berger, Georg Beckmann, Andrew Cherniack, Matthew Meyerson, Heidi Greulich. Preclinical activity of BAY 2927088 in HER2 mutant non-small cell lung cancer. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4035.
Abstract 4112: Evaluating the survival outcomes of an anti-isoaspELAVL4 response in a small cell lung cancer mouse model
Authors: Velarde Diego A. , Elmalh Sarah A. , Lee Hannah , Valdes Joseph , Gladstone Matthew , Dinigle Ryan E. , Kast Martin , Offringa Ite A.
Published: April 2023

Small cell lung cancer (SCLC) has a 95% mortality rate and a 5-year survival of 8%, resulting in the death of over 20,000 Americans each year. There has been marginal improvement in therapy over the past 30 years, with the recent addition of immune checkpoint inhibition therapy modestly increasing overall SCLC patient survival from 10.3 to 12.3 months [PMID 30280641]. This highlights the need for additional SCLC therapies. Previous studies have identified a subset of SCLC patients (10-20%) exhibiting a naturally occurring immune response called ‘anti-HuD’. It is associated with improved response to therapy and improved survival [PMID 9256130; 26606748]. Previous work identified the anti-HuD antigen to be ELAVL4. The Offringa lab and collaborators determined that the antigenic epitope consists of isoaspartylated ELAVL4 (isoAspELAVL4) [PMID 27725125]; the protein carries isoaspartylated residues in the N-terminal region (amino acids 1-36). All tested Anti-Hu-positive SCLC patient serum samples reacted with isoAspELAVL4, and all examined SCLC tissue samples stained positive for isoAspELAVL4 [PMID 27725125]. Here we used the Trp53fl/fl; Rb1fl/fl inducible SCLC mouse model [PMID 14522252] to examine 1) whether immunization with isoAspELAVL4 prior to SCLC induction is protective, and 2) whether immunization with isoAspELAVL4 following completion of 3 rounds of cisplatin+etoposide therapy increases survival. In both cases, mice were immunized with recombinant N-terminal fragment of ELAVL4 (amino acids 1-117) generated in Clear Coli and emulsified in incomplete Freund’s adjuvant (IFA) or control (phosphate-buffered saline in IFA). The trajectories of mice have been monitored with a detailed body metric score and blood has been drawn every 2 weeks to monitor the anti-ELAVL4 antibody response. Kaplan-Meier analysis will be used to assess survival differences between the immunized and control groups and will be presented. The study will provide insight into interplay between SCLC and the immune response to isoAspELAVL4.

Citation Format: Diego A. Velarde, Sarah A. Elmalh, Hannah Lee, Joseph Valdes, Matthew Gladstone, Ryan E. Dinigle, Martin Kast, Ite A. Offringa. Evaluating the survival outcomes of an anti-isoaspELAVL4 response in a small cell lung cancer mouse model. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4112.
Abstract 4296: Fast de novo antibody structure prediction with atomic accuracy
Authors: Wang Yining , Gong Xumeng , Li Shaochuan , Yang Bing , Sun Yiwu , Luo Yujie , Li Hui , Song Le
Published: April 2023

Background: In the field of antibody engineering, an essential task is to design a novel antibody whose paratopes bind to a specific antigen with correct epitopes. Understanding antibody structure and its paratope can facilitate a mechanistic understanding of its function. Therefore, antibody structure prediction from its sequence alone has always been a highly valuable problem for de novo antibody design. AlphaFold2 (AF2), a breakthrough in the field of structural biology, provides a solution to this protein structure prediction problem by learning a deep learning model. However, the computational efficiency and undesirable prediction accuracy on antibody, especially on the complementarity-determining regions limit its applications in de novo antibody design.

Methods: To learn informative representation of antibodies, we trained a deep antibody language model (ALM) on curated sequences from observed antibody space database via a well-designed transformer model. We also developed a novel model named xTrimoABFold++ to predict antibody structure from antibody sequence only based on the pretrained ALM as well as efficient evoformers and structural modules. The model was trained end-to-end on the antibody structures in PDB by minimizing the ensemble loss of domain-specific focal loss on CDR and the frame aligned point loss.

Results: xTrimoABFold++ outperforms AF2 and OmegaFold, HelixFold-Single with 30+% improvement on RMSD. Also, it is 151 times faster than AF2 and predicts antibody structure in atomic accuracy within 20 seconds. In recently released antibodies, for example, cemiplimab of PD-1 (PDB: 7WVM) and cross-neutralizing antibody 6D6 of SARS-CoV-2 (PDB: 7EAN), the RMSD of xTrimoABFold++ are 0.344 and 0.389 respectively.

Conclusion: To the best of our knowledge, xTrimoABFold++ achieved the state-of-the-art in antibody structure prediction. Its improvement on both accuracy and efficiency makes it a valuable tool for de novo antibody design, and could make further improvement in immuno-theory.

Experimental results on immune antibody dataset with 95% confidence interval. Method RMSD TMScore GDTTS GDTHA AlphaFold2 3.1254 ± 0.1410 0.8385 ± 0.0055 0.7948 ± 0.0057 0.6548 ± 0.0063 OmegaFold 3.2610 ± 0.1463 0.8384 ± 0.0057 0.7925 ± 0.0059 0.6586 ± 0.0063 HelixFold-Single 2.9648 ± 0.0997 0.8328 ± 0.0055 0.7805 ± 0.0057 0.6225 ± 0.0060 ESMFold 3.1549 ± 0.0067 0.8390 ± 0.0003 0.7952 ± 0.0003 0.6551 ± 0.0003 xTrimoABFold++ 1.9594 ± 0.0805 0.8986 ± 0.0052 0.8694 ± 0.0057 0.7456 ± 0.0066

Citation Format: Yining Wang, Xumeng Gong, Shaochuan Li, Bing Yang, Yiwu Sun, Yujie Luo, Hui Li, Le Song. Fast de novo antibody structure prediction with atomic accuracy. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4296.
Abstract 4466: Inhibition of ERO1a and IDO1 improves dendritic cell infiltration into pancreatic ductal adenocarcinoma
Authors: Tay Apple , Lundqvist Andreas , Sze Siu Kwan
Published: April 2023

Pancreatic ductal adenocarcinoma (PDAC) is one of the most hypoxic, lethal, and treatment resistant cancers. Due to its desmoplasias along with the hypoxic state and scarce infiltration of T cells, PDAC is considered a cold tumor. Using a proteomic approach, we previously identified that the expression of endoplasmic reticulum oxidoreductase 1 alpha (ERO1α) is induced by hypoxia and correlates with reduced survival in PDAC. Furthermore, we observed an increased kynurenine formation under hypoxia, suggesting a role of indoleamine 2,3-dioxygenases (IDO1) in PDAC. Since ERO1α and IDO are involved in driving immune suppression through influencing the generation of immature myeloid cells, we sought to investigate whether inhibition of these pathways modulates the myeloid cell composition in PDAC. Using MiaPaCa2 as a PDAC spheroid model with hypoxic core grown in serum-free defined media and immune cell infiltration, we assessed the functional role of ERO1a with IDO1 in modulating monocyte infiltration and differentiation into pro- and anti-inflammatory phenotypes, followed by characterizing the immunomodulatory factors secreted using tandem mass spectrometry. Inhibition of ERO1a and IDO1 significantly improved U937 monocyte infiltration (p-value = ****) and differentiation into dendritic cells (p-value = ****). Secretome analysis of proteins identified with high false discovery rate (q-value<0.01) revealed a downregulation of hypoxia and pancreatic cancer pathways in PDAC spheroids. In the presence of monocytes, upregulation of immune-related pathways for antigen presentation (15-fold) and myeloid cell maintenance signaling (2-fold) were observed. Moreover, specific immune-modulatory factors involved in immune infiltration and migration including interleukin 8, lymphocyte cytosolic protein 1 and transgelin-2 were upregulated at 27-, 20-, and 14-fold respectively. Taken together, these results indicate that inhibition of ERO1a and IDO1 drives an inflamed tumor microenvironment associated with improved monocyte infiltration and differentiation into dendritic cells to potentially enable T cell infiltration and killing of PDAC tumors.

Citation Format: Apple Tay, Andreas Lundqvist, Siu Kwan Sze. Inhibition of ERO1a and IDO1 improves dendritic cell infiltration into pancreatic ductal adenocarcinoma. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4466.
Abstract 4480: Treatment of PTEN/PI3K co-mutated endometrial adenocarcinoma with multitarget small molecule inhibitors
Authors: Delara Ritchie , McHale Cody , Pal Dhananjaya , Maddeboina Krishnaiah , Naumann R. Wendel , Crane Erin , Brown Jubilee , Durden Donald
Published: April 2023

Introduction: The objective of this study is to assess the feasibility and safety of treating endometrial adenocarcinoma (EC) with multitarget inhibitors which orthogonally target known oncogenic kinases and epigenetic regulators. The Molecular Targeted Therapeutics Laboratory has developed nanomolar potent multitarget small molecule chemotypes that inhibit the PI3K/Akt/mTOR pathway, cancer-associated kinases, and epigenetic regulatory proteins such as BRD4 in vitro and in vivo.

Methods: Two EC cell lines (AN3-CA, RL95-2) were treated with varying concentrations of triple PI3K/BRD4/CDK4/6/9 inhibitor LCI132 and dual PI3K/CDK4/6/9 inhibitors LCI133 and LCI136 for 48 hours; and cell viability assays were performed with IC50 determination. EC cells were treated with multitarget inhibitors and other indicated inhibitors of PI3K, BET, CDK4/6, and CDK9 for 24 hours; and lysates were prepared accordingly for Western blot (WB) and qRT-PCR analyses. Flow cytometry was conducted for cell cycle and apoptosis assays.

Results: In cell-free assays, LCI132 is a nanomolar inhibitor of PI3K/BRD4/CDK4/6/9, LCI133 is a picomolar inhibitor of CDK9, and LCI136 is a nanomolar inhibitor of PI3K and CDK9. LCI133 demonstrated nanomolar potency towards AN3-CA (IC50 248 nM) and RL95-2 (IC50 105 nM). LCI136 demonstrated nanomolar potency towards AN3-CA (IC50 631 nM) and RL95-2 (IC50 728 nM). WB demonstrated 24-hour treatment of FBXW7mut AN3-CA with LCI132 inhibited AKT phosphorylation but an increase in c-MYC protein expression. A corresponding increase in c-Myc gene expression at 24 hours was confirmed on qRT-PCR. In FBXW7wt RL95-2, LCI132 decreased c-Myc protein expression. LCI132 demonstrated dose-dependent G1 arrest, and dose-dependent pre-apoptotic and apoptotic activity.

Conclusions: Dual-target inhibitors LCI133 and LCI136 are nanomolar potent in AN3-CA and RL95-2 EC cell lines, suggesting a role of CDK9 inhibition of PTEN/PI3K co-mutated EC. Preliminary studies demonstrate an upregulation of MYC gene and protein expression in FBXW7mut EC but not FBXW7wt, and the role of FBXW7 as a predictive biomarker in treatment of PTEN/PIK3R1 co-mutated EC warrants further investigation.

Citation Format: Ritchie Delara, Cody McHale, Dhananjaya Pal, Krishnaiah Maddeboina, R. Wendel Naumann, Erin Crane, Jubilee Brown, Donald Durden. Treatment of PTEN/PI3K co-mutated endometrial adenocarcinoma with multitarget small molecule inhibitors. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4480.
Abstract 4481: Vrtx153, novel small molecule inhibitor of krasg12d
Authors: Bhavar Prashant Kashinath , Surampudi Uday Kumar , Sarma Partha Pratim , Kshirsagar Anuj Ramesh
Published: April 2023

Pancreatic cancer is an intractable malignancy and is the seventh leading cause of global cancer deaths in industrialized countries and the third most common in the USA. Despite advancement in the knowledge of potential risk factors that cause pancreatic cancer and newly available tools for early diagnosis, its incidence is estimated to increase and will include 0.35 mln new cases within 2040. KRAS is the predominant isoform mutated in cancer and are found in 92-95% of Pancreatic Cancer patients, dominated by somatic mutations of KRASG12D. KRASG12D, is one of the most frequently mutated oncogenes across adenocarcinoma of Pancreas (51%), Colon and Rectal (13.4%) and Lung (3%). With KRAS mutations found in nearly all PDAC, this cancer type is arguably the most RAS-addicted cancer. KRASG12D is a clinically relevant target but owing to structural complexity of the protein, poses challenges for its effective inhibition. Previously, we reported a series of compound including a proprietary tool compound VTRX144, with low nM potency in 2D (<25 nM). Optimized lead from VRise de-novo platform has yielded an unparallel potent, highly selective, inhibitor, namely VRTX153. VRTX153 demonstrated high-affinity for KRASG12D in a GDP-loaded KRASG12D assay, with an IC50 value of less than 2 nM and more than1500 -fold selectivity over KRASWT, KRAS mutants and other RAS proteins including HRAS & NRAS. VRTX153 inhibited ERK1/2 phosphorylation (pERK) and cell viability in KRASG12D-mutant cell lines in both 2D and 3D, as evaluated by CellTiter-Glo®. In-vivo translation of activity in a mouse xenograft model representing PDAC is being investigated.

Citation Format: Prashant Kashinath Bhavar, Uday Kumar Surampudi, Partha Pratim Sarma, Anuj Ramesh Kshirsagar. Vrtx153, novel small molecule inhibitor of krasg12d. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4481.
Abstract 4611: Leveraging organotypic brain slice models to enhance adoptive cellular therapies
Authors: Reid Alexandra , Jin Dan , DiVita-Dean Bayli , Falceto-Font Laura , Figg John , Francis Connor , Flores Catherine
Published: April 2023

Glioblastoma (GBM) is an incredibly aggressive and prevalent primary CNS tumor with dismal survival outcomes. GBM’s intra-tumor heterogeneity and lack of anti-tumor immune cell infiltration have proved to be formidable challenges to the development of effective therapies. These hurdles may be overcome by garnering a better understanding of the cell-cell interactions occurring within the tumor microenvironment (TME). Accounting for the complexity and the spatial orientation of the components within the TME may offer insight into the multitiered layers of immunosuppression capitalized on by GBM tumors, thus elucidating the factors responsible for poor response to therapy and uncovering potential therapeutic targets that may offer more favorable therapeutic results for immunotherapies. Current in vitro and in vivo models, however, sorely limit our ability to probe these distinct attributes while preserving the intricate nature of the TME. To bridge this gap, we have devised a novel organotypic brain slice culture (BSC) model using tumor-bearing C57BL/6J mice, allowing us to characterize the tumor milieu in situ. We have identified infiltration of myeloid-derived suppressor cells (MDSC) and microglia polarized to the M2 anti-inflammatory phenotype within the TME. Leveraging this platform, we sought to define further the factors contributing to the dynamic impacts of GBM immunosuppression, such as the tolerogenic response in dendritic cells (DC) upon interaction with the TME. We have demonstrated outcomes similar to those seen in vivo following the introduction of DCs to tumor-bearing BSCs, further supporting the physiological relevancy of this model, and have since worked to unravel elements responsible for this response.

Citation Format: Alexandra Reid, Dan Jin, Bayli DiVita-Dean, Laura Falceto-Font, John Figg, Connor Francis, Catherine Flores. Leveraging organotypic brain slice models to enhance adoptive cellular therapies. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4611.
Abstract 4669: A patient derived xenograft model for lung adenocarcinoma using Obagel®, a human derived hydrogel
Authors: Sanchez Cecilia , Nakashima Jonathan , King Kristein , Frazier Trivia
Published: April 2023

Patient Derived Xenografts (PDXs) are valuable disease models as they preserve the tumor microenvironment’s structure, providing the most clinically relevant in vivo testing platform. Nevertheless, most of those models still use animal derived hydrogels as scaffolds for patient derived cells, reducing the potential to fully mimic the physiological microenvironment of the disease and human condition. ObaGel® is a human-derived hydrogel successfully deployed for supporting 3D cell culture, organoid, perfusion bioreactor, and/microphysiological system development for studying obesity, type II diabetes, and various forms of related cancers. Here we are investigating the use of Obagel® in the in-vivo development of a PDX-derived culture of lung adenocarcinoma and compare its performance to currently used animal derived hydrogels. Methods: 3 × 10^6 CRT00295 Non-small cell lung adenocarcinoma cells in 100ul 50:50 indicated Gel in PBS per injection site; the study used 10 NOG mice per condition. Results: The results indicated that ObaGel® performed similarly in terms of engraftment and tumor kinetics compared to animal derived hydrogels such as Cultrex, Geltrex, and Matrigel, using a patient-derived xenograft culture of lung adenocarcinoma. Conclusions: Our data supports the use of a human-derived hydrogel for PDX models, ObaGel® performs equivalently to animal derived hydrogels to support tumor volume over time. The use of a human derived hydrogels as scaffolds for PDX models provide a better humanized local microenvironment for lung adenocarcinoma. Obagel® can also be adapted for use as xenografts in other tissue/disease models

Citation Format: Cecilia Sanchez, Jonathan Nakashima, Kristein King, Trivia Frazier. A patient derived xenograft model for lung adenocarcinoma using Obagel®, a human derived hydrogel. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4669.
Abstract 470: A MDM2 degrader inhibits cell proliferation and growth of MDM2-overexpressing acute lymphoblastic leukemia in SCID mice
Authors: Liu tao , Gu Lubing , Mui Anna , Wu Zhongzhi , Li Wei , Zhou Muxiang
Published: April 2023

The MDM2 oncogene is amplified and/or overexpressed in various human cancers and elevated expression of MDM2 protein acts as a survival factor promoting cancer progression mainly through inhibition of the tumor suppressor p53. Here, we report a novel small-molecule chemical compound (MX69-114b) that we identified to induce MDM2 protein degradation resulting in reactivation of p53 and potent cell growth inhibition and apoptosis in MDM2-overexpressing acute lymphoblastic leukemia (ALL). We have previously identified a compound (MX69) that binds to the MDM2 C-terminal RING domain and induces MDM2 protein degradation. In the present study, we performed structural modification of MX69 and selected analog MX69-114b showing increased MDM2-targeting activity. MX69-114b exhibited significantly enhanced inhibitory and apoptotic effects on a group of MDM2-overexpressing ALL cell lines in vitro with IC50 values of 0.08-0.14 µM, representing a >80-100-fold increase in activity compared to MX69. MX69-114b also showed inhibitory effects on xenografted human MDM2-overexpressing ALL in SCID mice at a much lower dose than did MX69. Importantly, MX69-114b had minimal or no inhibitory effect on normal human hematopoiesis in vitro and was very well tolerated in vivo in animal models. Based on the strong inhibitory and apoptotic activity against MDM2-overexpressing ALL, along with minimal or no toxicity to normal cells/tissues, MX69-114b is a candidate for further development as a novel MDM2-targeted therapeutic drug for refractory ALL.

Citation Format: tao Liu, Lubing Gu, Anna Mui, Zhongzhi Wu, Wei Li, Muxiang Zhou. A MDM2 degrader inhibits cell proliferation and growth of MDM2-overexpressing acute lymphoblastic leukemia in SCID mice [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 470.
Abstract 471: A new synthetic peptide DS-2 enhanced anti-tumor activity by targeting human telomerase reverse transcriptase (hTERT) in prostate cancer cells
Authors: Park Jae Hyeon , Shin Joo Kyung , Han Joo Hee , Kim Hyung Sik
Published: April 2023

Human telomerase reverse transcriptase (hTERT) is overexpressed in most human cancers. Therefore, hTERT is considered as an important target for cancer therapy. In the present study, we synthetized a new peptide, DS-2, based on the telomerase vaccine GV1001, a 16-mer peptide. The aim of this study is to evaluate the molecular mechanism of DS-2 on the anticancer activity by targeting hTERT in prostate cancer cells. The expression levels of hTERT in prostate cancer patients were measured. We compared the cytotoxic activity of GV1001 and DS-2 against different prostate cancer cell lines. Flow cytometry was used to evaluate the effects of DS-2 on apoptosis. The scratch-wound assay and matrigel invasion assay were performed to determine the metastasis ability of prostate cancer cells. We further measured the telomerase enzyme activity of DS-2 in LNCaP cells. Furthermore, tumor-bearing nude mice were employed to evaluate the anticancer effect of GV1001 and DS-2. The cytotoxicity of human peripheral blood mononuclear cells (PBMC) on prostate cancer cells was determined by lactate-dehydrogenase (LDH)-release assay. The hTERT expression was directly correlated with telomerase activity in LNCaP cells, and DS-2 significantly inhibited telomerase enzyme activity, resulting in reducing LNCaP cells proliferation and metastasis. Furthermore, DS-2 exhibited the most substantial anti-cancer potential against prostate cancer cells compared with different cancer cell lines. In the tumor-bearing nude mice model, DS-2 significantly inhibited the growth of the prostate tumor and downregulated the expression of hTERT and Ki-67 in the tumor tissue as evidenced by western blot and immunohistochemistry analysis, respectively. Furthermore, the potent cytotoxicity was exhibited in LNCaP cells after treated with DS-2-activated PBMC plus IL-2. In addition, DS-2 synergistically enhanced IL-2 production from activated PBMC. These data indicated that the inhibition of hTERT expression by DS-2 suppressed prostate cancer cell growth and induced anti-cancer immunity. Therefore, DS-2 might be used as a novel therapeutic drug for cancer immunotherapy by targeting hTERT in prostate cancer.

Citation Format: Jae Hyeon Park, Joo Kyung Shin, Joo Hee Han, Hyung Sik Kim. A new synthetic peptide DS-2 enhanced anti-tumor activity by targeting human telomerase reverse transcriptase (hTERT) in prostate cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 471.
Abstract 4766: Hypoxia increases the methylated histones to prevent histone clipping during Raf-induced senescence
Authors: Park Hyunsung , Chang Soojeong
Published: April 2023

Hypoxia increases methylated histones by inhibiting O2- and α-ketoglutarate-dependent histone lysine demethylases (KDMs). This study is the first to demonstrate how the hypoxic increment of methylated histones cross-talks with other epigenetic changes, such as histone clipping and heterochromatin redistribution, named senescence-associated heterochromatin foci (SAHF), which are found during oncogene-induced senescence (OIS). Raf-activation in primary human fibroblasts IMR90 increases mature cathepsin L (CTSL)-mediated clipping of histone H3, H2B and H4. Hypoxia protects histones from CTSL by increasing histone methylation without reducing the amount and activity of CTSL. Forced enhancement of methylated histones protected histones from clipping during OIS, even under normoxia, but failed to block SAHFs. Altogether, these results suggest that maintenance of methylated histones is sufficient to protect histones from CTSL, not sufficient but necessary for inhibiting SAHFs, suggesting that besides inhibiting KDMs, hypoxia adopts other mechanisms to inhibit SAHFs. Hypoxia protects histones and chromatin from dramatic epigenetic changes by increasing methylated histones.

Citation Format: Hyunsung Park, Soojeong Chang. Hypoxia increases the methylated histones to prevent histone clipping during Raf-induced senescence. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4766.
Abstract 4779: MnSOD mimetic mitoquinone mesylate (MitoQ) increases DCLK1+pancreatic cancer stem cells
Authors: Perera Jeffrey Mario , Martinez Alicia K. Fleming , Storz Peter
Published: April 2023

Mitochondrially-generated reactive oxygen species (mROS) have been shown to induce acinar-to-ductal metaplasia (ADM). ADM, in presence of an oncogenic KRAS mutation, is an initiating step for progression to pancreatic intraepithelial neoplasia (PanIN) and eventually pancreatic ductal adenocarcinoma (PDA). Here, we utilize primary murine cells as well as the p48Cre;LSL-KrasG12D (KC) mouse model to explore the use of the mitochondria-targeted mimetic of manganese superoxide dismutase MitoQ for targeting PDA initiation and progression. Previously published data by our laboratory has shown that treatment with MitoQ decreases the abundance of pancreatic low-grade lesions in KC mice. However, we here demonstrate that superoxide depletion by MitoQ at the same time increases formation of DCLK1+ cancer stem cells in such lesions. We here evaluate if the detoxification of mitochondrial superoxide results in a build-up of hydrogen peroxide, which is a major driver of the DCLK1+ cell type. We determine how altered expression of ROS detoxifying enzymes in different cell types contribute to PDA stem cell formation and PDA development. Eventually we test if the increase in DCLK1+ cancer stem cells can contribute to changes in the microenvironment and accelerated progression of abnormal tissue.

Citation Format: Jeffrey Mario Perera, Alicia K. Fleming Martinez, Peter Storz. MnSOD mimetic mitoquinone mesylate (MitoQ) increases DCLK1+pancreatic cancer stem cells. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4779.
Abstract 4923: Prostaglandin E2 receptor EP2: A novel target for high-risk neuroblastoma
Authors: Hou Ruida , Yu Ying , Yang Jun , Jiang Jianxiong
Published: April 2023

Neuroblastoma (NB) is the most common pediatric extracranial solid tumor. Based on tumor stage and histological features, 50% of NBs are classified as high-risk diseases, a subtype characterized by a quite unsatisfactory long-term survival even with the striking advances in NB management that have been achieved in the past decades. Cyclooxygenase-2/prostaglandin E2 (COX-2/PGE2) cascade has been reported to foster a proinflammatory tumor-nourishing microenvironment in NB. However, the specific downstream PGE2 receptor (EP) subtype which directly mediates this tumor promoting effect remains elusive. Therefore, in our research, we aim to 1) elucidate the culprit EP receptor that is directly involved in NB development; 2) evaluate the feasibility of inhibiting the PGE2 receptor subtype as a novel treatment strategy for high-risk NB. To start with, we analyzed the gene expression profiles of the COX2/PGE2/EP pathway from four major NB datasets (Versteeg, Kocak, SEQC, and NRC) on R2 platform. It indicates that the COX-2/PGE2/EP2 signaling axis is highly associated with the expression of high-risk NB markers, as well as an abysmal overall survival rate. Moreover, a time resolved fluorescence resonance energy transfer (TR-FRET) method was adopted to reveal that EP2 receptor is the key Gαs-coupled receptor that mediates PGE2-initiated cAMP signaling in high-risk NB cell lines. Genetic interference of EP2 receptor expression by CRISPR/Cas9-mediated genome editing and doxycycline induced conditional knockdown significantly inhibited high-risk NB development and progression both in neuro-sphere formation assay and in nude mice xenograft models. Finally, we tested the anti-NB efficacy of our recently developed selective and bioavailable small-molecule EP2 antagonists. With a consecutive treatment of three weeks, decreased tumor size and weight have been observed in both high-risk NB xenograft model and immunocompetent allograft model, simultaneously with decreased inflammation, angiogenesis, and enhanced apoptosis. Collectively, our results suggest that the PGE2/EP2 pathway contributes to the growth and malignant potential of high-risk NB; pharmacological inhibition on EP2 receptor by our drug-like compounds might provide a novel therapeutic strategy for this deadly pediatric cancer.

Citation Format: Ruida Hou, Ying Yu, Jun Yang, Jianxiong Jiang. Prostaglandin E2 receptor EP2: A novel target for high-risk neuroblastoma. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4923.
Abstract 4972: Anti-tumor activity of Helicon inhibitors of Β-catenin-TCF interaction in patient-derived xenograft models
Authors: Si YaGuang , Choi Minjung , Han Xinwei , White Brian , Wu Ziyang , Visness Erica , Beerepoot Pieter , Jaensch Elizabeth , Ramirez Jessica , Ponthier Charles , Han Xiaogang , Ortet Paula , Du Peicheng , Agarwal Sorabh , Lech Mirek , Fulgham Aaron , Cappucci Sarah , Li Zhi , McGee John , Yu Lihua , Tremblay Martin , Orford Keith , Verdine Gregory , Hurov Jonathan
Published: April 2023

Genetic and epigenetic alterations in the Wnt signaling pathway leading to constitutive activation of the driver oncogene Β-catenin occur in at least 20% of all human cancers. We have developed conformationally hyperstabilized α-helical peptides (Helicons) that bind directly to Β-catenin with picomolar affinity and block its interaction with TCF transcription factors. We describe here the characterization of anti-tumor efficacy, pharmacodynamic biomarkers and mechanism of action using multiple in vivo patient-derived xenograft (PDX) models treated with Helicons. Helicon treatment leads to dose-dependent anti-tumor effects and durable regressions in PDX models from multiple indications with Wnt pathway activating mutations. Anti-tumor responses are seen in the presence of additional driver mutations, including KRAS and PIK3CA. RNA-sequencing and Gene Set Enrichment Analysis confirm Helicon treatment inhibits both Wnt/Β-catenin and MYC-regulated gene sets. Inhibiting Β-catenin-TCF interaction with Helicons represents a first-in-class therapeutic approach for the treatment of cancers resulting from aberrant transcriptional signaling via Β-catenin.

Citation Format: YaGuang Si, Minjung Choi, Xinwei Han, Brian White, Ziyang Wu, Erica Visness, Pieter Beerepoot, Elizabeth Jaensch, Jessica Ramirez, Charles Ponthier, Xiaogang Han, Paula Ortet, Peicheng Du, Sorabh Agarwal, Mirek Lech, Aaron Fulgham, Sarah Cappucci, Zhi Li, John McGee, Lihua Yu, Martin Tremblay, Keith Orford, Gregory Verdine, Jonathan Hurov. Anti-tumor activity of Helicon inhibitors of Β-catenin-TCF interaction in patient-derived xenograft models. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4972.
Abstract 4974: Development of novel pyrimido-pyrazolo-quinolone derivative, IND-2 as multi-targeted inhibitor for the treatment of prostate cancer
Authors: Balaji Swapnaa , Neupane Rabin , Karthikeyan Chandrabose , Ramapuram Jayachandra Babu , Tiwari Amit K.
Published: April 2023

Prostate cancer (PC) is the most commonly diagnosed cancer in men. In PC, multiple molecular signaling networks are perturbed, so monotherapies are less effective, creating an urgent need to discover chemotherapeutic agents that target multiple tumor-promoting proteins simultaneously. Drug discovery research is increasingly embracing poly-pharmacology, in which one drug targets multiple oncogenic targets concurrently. We have identified a novel quinoline derivative, IND-2 (4-chloro-2-methylpyrimido[1″,2″:1,5]pyrazolo[3,4-b]quinolone), that has been shown to significantly inhibit the expression of several oncogenic and epigenetic targets in PC cells. It was observed that IND-2 significantly inhibited the proliferation of PC-3 and DU-145 with IC50 values of 3 µM and 3.5 µM, respectively. Furthermore, 5 and 10 µM of IND-2 produced morphological changes in PC-3 cells characteristic of apoptosis. The levels of reactive oxygen species (ROS) increased significantly after IND-2 was added to PC cells. Additionally, 5 and 10 µM of IND-2 reduced mitochondrial membrane potential in PC-3 cells. Furthermore, IND-2 increased the expression of cleaved caspase-3, cleaved caspase-7, and cleaved poly (ADP-ribose) polymerase (PARP). The PC-3 cells incubated with 5 µM of IND-2 showed a significant reduction in expression of B-cell lymphoma 2 (Bcl-2). These data convincingly show that IND-2 inhibits PC cells through apoptosis induction. It is interesting to note that IND-2 (2.5, 5 and 10 µM) also induces mitotic catastrophe in PC-3 cells. Wound healing assay and expression of several EMT (epithelial to mesenchymal) markers indicated significant anti-metastatic activity of IND-2. Target identification studies have demonstrated that IND-2 mimics etoposide (VP-16) and binds more specifically to Topoisomerase IIβ. In our preliminary studies, we found that IND-2 inhibits several oncogenic and epigenetic targets including Topoisomerase II-Hsp90 complex and LSD1/HDAC1 of the transcriptional corepressor CoREST complex. However, these targets need to be validated to understand IND-2's mechanism. Overall, IND-2 may lead to the development of more effective poly-targeted compounds for PC treatment.

Citation Format: Swapnaa Balaji, Rabin Neupane, Chandrabose Karthikeyan, Jayachandra Babu Ramapuram, Amit K. Tiwari. Development of novel pyrimido-pyrazolo-quinolone derivative, IND-2 as multi-targeted inhibitor for the treatment of prostate cancer. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4974.
Abstract 4990: Dual inhibitor of ACVR1 and MEK 1/2 E6201 and PI3K/mTOR inhibitor paxalisib synergistically inhibit cell growth in DMG
Authors: Kwon Hyuk Jean , Tindall Abigail , Eberhart Charles , Rubens Jeffrey , Raabe Eric
Published: April 2023

Diffuse midline glioma (DMG) is an aggressive pediatric glioma with no curative treatment options. Mutation in MAPK pathway is common in many DMG tumors, however, has not been largely explored before. E6201 is a dual inhibitor of ACVR1 and MEK 1/2. It is currently in a phase 1 clinical trial for BRAF/MEK mutant melanoma. E6201 achieves higher levels in brain compared to other MEK inhibitors, suggesting it might be a promising therapeutic option for DMG. Previously, E6201 was effective in DMG cell lines with ACVR1 mutation, such as HSJD007. We have evaluated the effect of E6201 in two MAP kinase pathway activated, novel DMG cell lines, DIPG2JA and JHH-DIPG17. DIPG2JA has a KRAS mutation, leading to upregulation of MAPK pathway, and JHH-DIPG17 has two NF1 alterations predicted to disrupt this tumor suppressor, resulting in activation of MAPK pathway. Treatment of DIPG2JA with E6201 identified an IC50 of 44 nM, which is comparable to an IC50 of 71nM in the ACVR1 mutant DMG HSJD007. E6201 suppressed phospho—ERK and induced apoptosis as measured by cPARP western blot in DMG cells. Evaluation of cell viability by CellTiterBlue viability assay demonstrated that E6201 suppressed DMG growth between 0.05uM to 1uM concentrations. (DIPG2JA p=0.0004, JHH-DIPG17 p<0.0001 by t-test compared to control). Compensatory upregulation of mTOR pathway is often associated with downregulation of MAPK pathway, and we hypothesized that E6201 will synergize with a PI3K/mTOR inhibitor to induce DMG cell death. We selected the brain-penetrant PI3K/mTOR inhibitor paxalisib, because this drug is currently being tested in early phase clinical trials for DMG. Through CellTiterBlue cell viability assay, we showed that E6201 synergizes with paxalisib to inhibit cell growth. The ZIP synergy scores were 13.1 for HSJD007 and 12.7 for DIPG2JA according to the SynergyFinder program, suggesting synergistic interaction between E6201 and paxalisib. In vitro experiments for further evaluation of the combination treatment of E6201 and paxalisib are underway and in vivo studies are pending. From our data, E6201 as a single agent is a promising therapeutic option for DMG. With further evaluation of combination of E6201 and paxalisib, we believe that combination therapy will be an even more effective treatment option for DMG.

Citation Format: Hyuk Jean Kwon, Abigail Tindall, Charles Eberhart, Jeffrey Rubens, Eric Raabe. Dual inhibitor of ACVR1 and MEK 1/2 E6201 and PI3K/mTOR inhibitor paxalisib synergistically inhibit cell growth in DMG. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4990.
Abstract 5012: Characterizing the functional significance of PDGFRAK385I and PDGFRAK385L extracellular domain mutations in the newly defined myxoid glioneuronal tumor
Authors: Beach Catherine Z. , Somwar Romel , Wood Matthew D. , Davare Monika A.
Published: April 2023

In 2021, the World Health Organization (WHO) approved new diagnostic guidelines that stratify central nervous system (CNS) tumors based on molecular, transcriptomic, and epigenetic analysis instead of relying solely on phenotypic characterization and added twenty-two new CNS tumor entities based on these guidelines. Our focus is on one of these newly defined entities—myxoid glioneuronal tumors—a slow growing, mucinous glial tumor defined by a pathognomonic dinucleotide substitution in the extracellular domain of PDGFRA p.K385I/L. PDGFRA p.K385I/L remains a variant of unknown significance, however, constitutive activation of PDGFRA is well established as a pharmacologically actionable, oncogenic driver present in a variety of tumor types. Here we report the functional characterization of PDGFRAK385I and PDGFRAK385L by assessing transforming potential using Ba/F3 cells and immortalized human astrocytes. Our results demonstrate that both p.K385I and K385L substitutions are oncogenic, driving cytokine-independent Ba/F3 cell growth and anchorage-independent colony formation. Western blot analysis of downstream cellular signaling pathways in the absence of PDGF-ligand further confirm the activating nature of these mutations, showing robust phosphorylation of PDGFRA and constitutive phosphorylation of downstream signaling effectors ERK1/2, SHP2, and STAT3. To assess whether PDGFRAK385I and PDGFRAK385L are pharmacologically actionable, we tested multiple tyrosine kinase inhibitors with known activity against PDGFRA aberrant cancers using our mutant-transformed PDGFRA Ba/F3 cells. We found that the PDGFRAK385I and PDGFRAK385L mutants were sensitive to inhibitors axitinib, AZD-3229, and avapritinib at therapeutically relevant concentrations. Further, these mutants showed resistance to imatinib, nilotinib, and crenolanib underscoring the importance of pharmacogenomic investigation. No appreciable difference in sensitivity or resistance profiles was observed between the two mutants. In summary, our findings indicate that these previously uncharacterized p.K385I/L extracellular domain mutations in PDGFRA are oncogenic and represent a pharmacologically actionable target that could be harnessed to increase therapeutic options in the setting of myxoid glioneuronal tumors.

Citation Format: Catherine Z. Beach, Romel Somwar, Matthew D. Wood, Monika A. Davare. Characterizing the functional significance of PDGFRAK385I and PDGFRAK385L extracellular domain mutations in the newly defined myxoid glioneuronal tumor. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 5012.