bluuebunny/crossref_metadata_2025 huggingface dataset:
Data from A Patient-derived Xenograft Model of Pancreatic Neuroendocrine Tumors Identifies Sapanisertib as a Possible New Treatment for Everolimus-resistant Tumors
Authors: Chamberlain Chester E. , German Michael S. , Yang Katherine , Wang Jason , VanBrocklin Henry , Regan Melanie , Shokat Kevan M. , Ducker Gregory S. , Kim Grace E. , Hann Byron , Donner David B. , Warren Robert S. , Venook Alan P. , Bergsland Emily K. , Lee Danny , Wang Yucheng , Nakakura Eric K.
Published: April 2023

Abstract
Patients with pancreatic neuroendocrine tumors (PNET) commonly develop advanced disease and require systemic therapy. However, treatment options remain limited, in part, because experimental models that reliably emulate PNET disease are lacking. We therefore developed a patient-derived xenograft model of PNET (PDX-PNET), which we then used to evaluate two mTOR inhibitor drugs: FDA-approved everolimus and the investigational new drug sapanisertib. PDX-PNETs maintained a PNET morphology and PNET-specific gene expression signature with serial passage. PDX-PNETs also harbored mutations in genes previously associated with PNETs (such as MEN1 and PTEN), displayed activation of the mTOR pathway, and could be detected by Gallium-68 DOTATATE PET-CT. Treatment of PDX-PNETs with either everolimus or sapanisertib strongly inhibited growth. As seen in patients, some PDX-PNETs developed resistance to everolimus. However, sapanisertib, a more potent inhibitor of the mTOR pathway, caused tumor shrinkage in most everolimus-resistant tumors. Our PDX-PNET model is the first available, validated PDX model for PNET, and preclinical data from the use of this model suggest that sapanisertib may be an effective new treatment option for patients with PNET or everolimus-resistant PNET.
Data from Estrogen Receptor Pathway Activity Score to Predict Clinical Response or Resistance to Neoadjuvant Endocrine Therapy in Primary Breast Cancer
Authors: Inda Márcia A. , Blok Erik J. , Kuppen Peter J.K. , Charehbili Ayoub , den Biezen-Timmermans Eveline C. , van Brussel Anne , Fruytier Sevgi E. , Meershoek-Klein Kranenbarg Elma , Kloet Susan , van der Burg Bart , Martens John W.M. , Sims Andrew H. , Turnbull Arran K. , Dixon J. Michael , Verhaegh Wim , Kroep Judith R. , van de Velde Cornelis J.H. , van de Stolpe Anja
Published: April 2023

Abstract
Endocrine therapy is important for management of patients with estrogen receptor (ER)–positive breast cancer; however, positive ER staining does not reliably predict therapy response. We assessed the potential to improve prediction of response to endocrine treatment of a novel test that quantifies functional ER pathway activity from mRNA levels of ER pathway–specific target genes. ER pathway activity was assessed on datasets from three neoadjuvant-treated ER-positive breast cancer patient cohorts: Edinburgh: 3-month letrozole, 55 pre-/2-week/posttreatment matched samples; TEAM IIa: 3- to 6-month exemestane, 49 pre-/28 posttreatment paired samples; and NEWEST: 16-week fulvestrant, 39 pretreatment samples. ER target gene mRNA levels were measured in fresh-frozen tissue (Edinburgh, NEWEST) with Affymetrix microarrays, and in formalin-fixed paraffin-embedded samples (TEAM IIa) with qRT-PCR. Approximately one third of ER-positive patients had a functionally inactive ER pathway activity score (ERPAS), which was associated with a nonresponding status. Quantitative ERPAS decreased significantly upon therapy (P < 0.001 Edinburgh and TEAM IIa). Responders had a higher pretreatment ERPAS and a larger 2-week decrease in activity (P = 0.02 Edinburgh). Progressive disease was associated with low baseline ERPAS (P = 0.03 TEAM IIa; P = 0.02 NEWEST), which did not decrease further during treatment (P = 0.003 TEAM IIa). In contrast, the staining-based ER Allred score was not significantly associated with therapy response (P = 0.2). The ERPAS identified a subgroup of ER-positive patients with a functionally inactive ER pathway associated with primary endocrine resistance. Results confirm the potential of measuring functional ER pathway activity to improve prediction of response and resistance to endocrine therapy.
Data from A Novel Theranostic Strategy for MMP-14–Expressing Glioblastomas Impacts Survival
Authors: Mohanty Suchismita , Chen Zixin , Li Kai , Morais Goreti Ribeiro , Klockow Jessica , Yerneni Ketan , Pisani Laura , Chin Frederick T. , Mitra Siddharta , Cheshier Samuel , Chang Edwin , Gambhir Sanjiv Sam , Rao Jianghong , Loadman Paul M. , Falconer Robert A. , Daldrup-Link Heike E.
Published: April 2023

Abstract
Glioblastoma (GBM) has a dismal prognosis. Evidence from preclinical tumor models and human trials indicates the role of GBM-initiating cells (GIC) in GBM drug resistance. Here, we propose a new treatment option with tumor enzyme-activatable, combined therapeutic and diagnostic (theranostic) nanoparticles, which caused specific toxicity against GBM tumor cells and GICs. The theranostic cross-linked iron oxide nanoparticles (CLIO) were conjugated to a highly potent vascular disrupting agent (ICT) and secured with a matrix-metalloproteinase (MMP-14) cleavable peptide. Treatment with CLIO-ICT disrupted tumor vasculature of MMP-14–expressing GBM, induced GIC apoptosis, and significantly impaired tumor growth. In addition, the iron core of CLIO-ICT enabled in vivo drug tracking with MR imaging. Treatment with CLIO-ICT plus temozolomide achieved tumor remission and significantly increased survival of human GBM-bearing mice by more than 2-fold compared with treatment with temozolomide alone. Thus, we present a novel therapeutic strategy with significant impact on survival and great potential for clinical translation. Mol Cancer Ther; 16(9); 1909–21. ©2017 AACR.
Data from Cyclin-Dependent Kinase-9 Is a Therapeutic Target in MYC-Expressing Diffuse Large B-Cell Lymphoma
Authors: Hashiguchi Taylor , Bruss Nur , Best Scott , Lam Vi , Danilova Olga , Paiva Cody J. , Wolf Joelle , Gilbert Erin W. , Okada Craig Y. , Kaur Prabhjot , Drew Lisa , Cidado Justin , Hurlin Peter , Danilov Alexey V.
Published: April 2023

Abstract
Deregulation of the MYC transcription factor is a key driver in lymphomagenesis. MYC induces global changes in gene expression that contribute to cell growth, proliferation, and oncogenesis by stimulating the activity of RNA polymerases. A key feature in its ability to stimulate RNA Pol II activity is recruitment of pTEFb, an elongation factor whose catalytic core comprises CDK9/cyclin T complexes. Hence, MYC expression and function may be susceptible to CDK9 inhibition. We conducted a pre-clinical assessment of AZ5576, a selective CDK9 inhibitor, in diffuse large B-cell lymphoma (DLBCL). The in vitro and in vivo effects of AZ5576 on apoptosis, cell cycle, Mcl-1, and MYC expression were assessed by flow cytometry, immunoblotting, qPCR and RNA-Seq. We demonstrate that, in addition to depleting Mcl-1, targeting CDK9 disrupts MYC oncogenic function. Treatment with AZ5576 inhibited growth of DLBCL cell lines in vitro and in vivo, independent of cell-of-origin. CDK9 inhibition downregulated Mcl-1 and MYC mRNA transcript and protein in a dose-dependent manner. MYC-expressing cell lines demonstrated enhanced susceptibility to AZ5576. CDK9 inhibition promoted turnover of MYC protein, and decreased MYC phosphorylation at the stabilizing Ser62 residue and downregulated MYC transcriptional targets in DLBCL cells, a finding confirmed in a functional reporter assay, suggesting that CDK9 may govern MYC protein turnover, thus regulating its expression through multiple mechanisms. Our data suggest that targeting CDK9 is poised to disrupt MYC oncogenic activity in DLBCL and provide rationale for clinical development of selective CDK9 inhibitors.
Data from Itraconazole-Induced Inhibition on Human Esophageal Cancer Cell Growth Requires AMPK Activation
Authors: Chen Min-Bin , Liu Yuan-Yuan , Xing Zhao-Yu , Zhang Zhi-Qing , Jiang Qin , Lu Pei-Hua , Cao Cong
Published: April 2023

Abstract
We here evaluated the antiesophageal cancer cell activity by the antifungal drug itraconazole. Our results show that μg/mL concentrations of itraconazole potently inhibited survival and proliferation of established (TE-1 and Eca-109) and primary human esophageal cancer cells. Itraconazole activated AMPK signaling, which was required for subsequent esophageal cancer cell death. Pharmacologic AMPK inhibition, AMPKα1 shRNA, or dominant negative mutation (T172A) almost completely abolished itraconazole-induced cytotoxicity against esophageal cancer cells. Significantly, itraconazole induced AMPK-dependent autophagic cell death (but not apoptosis) in esophageal cancer cells. Furthermore, AMPK activation by itraconazole induced multiple receptor tyrosine kinases (RTKs: EGFR, PDGFRα, and PDGFRβ), lysosomal translocation, and degradation to inhibit downstream Akt activation. In vivo, itraconazole oral gavage potently inhibited Eca-109 tumor growth in SCID mice. It was yet ineffective against AMPKα1 shRNA-expressing Eca-109 tumors. The in vivo growth of the primary human esophageal cancer cells was also significantly inhibited by itraconazole administration. AMPK activation, RTK degradation, and Akt inhibition were observed in itraconazole-treated tumors. Together, itraconazole inhibits esophageal cancer cell growth via activating AMPK signaling. Mol Cancer Ther; 17(6); 1229–39. ©2018 AACR.
Data from TAS-121, A Selective Mutant EGFR Inhibitor, Shows Activity Against Tumors Expressing Various EGFR Mutations Including T790M and Uncommon Mutations G719X
Authors: Ito Kimihiro , Nishio Makoto , Kato Masanori , Murakami Haruyasu , Aoyagi Yoshimi , Ohe Yuichiro , Okayama Takashige , Hashimoto Akihiro , Ohsawa Hirokazu , Tanaka Gotaro , Nonoshita Katsumasa , Ito Satoru , Matsuo Kenichi , Miyadera Kazutaka
Published: April 2023

Abstract
TAS-121 is a novel orally active selective covalent inhibitor of the mutant EGFR. We performed preclinical characterization of TAS-121 and compared its efficacy and selectivity for common EGFR mutations (Ex19del and L858R), first- and second- generation EGFR-tyrosine kinase inhibitor (EGFR-TKI) resistance mutation (T790M), and uncommon mutations (G719X and L861Q) with those of other EGFR-TKIs. We also commenced investigation of the clinical benefits of TAS-121. The IC50 for intracellular EGFR phosphorylation was determined by using Jump-In GripTite HEK293 cells transiently transfected with EGFR expression vectors. Mouse xenograft models were used to evaluate the antitumor activity of TAS-121. TAS-121 potently inhibited common activating and resistance EGFR mutations to the same extent as another third-generation EGFR-TKI (osimertinib). In addition, TAS-121 showed equivalent inhibitory activity against some uncommon mutations such as G719X and L861Q. Furthermore, TAS-121 demonstrated greater selectivity for mutant EGFRs versus the wild-type EGFR compared with other EGFR-TKIs. Moreover, TAS-121 displayed antitumor activity in SW48 (EGFR G719S) and NCI-H1975 (EGFR L858R/T790M) xenograft models, and achieved an objective response in patients with NSCLC with EGFR mutations including G719A mutation. In conclusion, TAS-121 is a novel third-generation EGFR-TKI and demonstrates antitumor activities in patients with NSCLC expressing either common or uncommon EGFR mutations.
Data from Development of Therapeutic Anti-JAGGED1 Antibodies for Cancer Therapy
Authors: Masiero Massimo , Li Demin , Whiteman Pat , Bentley Carol , Greig Jenny , Hassanali Tasneem , Watts Sarah , Stribbling Stephen , Yates Jenna , Bealing Ellen , Li Ji-Liang , Chillakuri Chandramouli , Sheppard Devon , Serres Sébastien , Sarmiento-Soto Manuel , Larkin James , Sibson Nicola R. , Handford Penny A. , Harris Adrian L. , Banham Alison H.
Published: April 2023

Abstract
The role of Notch signaling and its ligand JAGGED1 (JAG1) in tumor biology has been firmly established, making them appealing therapeutic targets for cancer treatment. Here, we report the development and characterization of human/rat-specific JAG1-neutralizing mAbs. Epitope mapping identified their binding to the Notch receptor interaction site within the JAG1 Delta/Serrate/Lag2 domain, where E228D substitution prevented effective binding to the murine Jag1 ortholog. These antibodies were able to specifically inhibit JAG1-Notch binding in vitro, downregulate Notch signaling in cancer cells, and block the heterotypic JAG1-mediated Notch signaling between endothelial and vascular smooth muscle cells. Functionally, in vitro treatment impaired three-dimensional growth of breast cancer cell spheroids, in association with a reduction in cancer stem cell number. In vivo testing showed variable effects on human xenograft growth when only tumor-expressed JAG1 was targeted (mouse models) but a more robust effect when stromal-expressed Jag1 was also targeted (rat MDA-MB-231 xenograft model). Importantly, treatment of established triple receptor-negative breast cancer brain metastasis in rats showed a significant reduction in neoplastic growth. MRI imaging demonstrated that this was associated with a substantial improvement in blood–brain barrier function and tumor perfusion. Lastly, JAG1-targeting antibody treatment did not cause any detectable toxicity, further supporting its clinical potential for cancer therapy.
Data from RAC1b Overexpression Confers Resistance to Chemotherapy Treatment in Colorectal Cancer
Authors: Goka Erik T. , Chaturvedi Pallavi , Lopez Dayrelis T. Mesa , Garza Adriana De La , Lippman Marc E.
Published: April 2023

Abstract
Resistance to chemotherapy represents a major limitation in the treatment of colorectal cancer. Novel strategies to circumvent resistance are critical to prolonging patient survival. Rac1b, a constitutively activated isoform of the small GTPase Rac1, is upregulated with disease progression and promotes cell proliferation and inhibits apoptosis by activation of NF-κB signaling. Here, we show that Rac1b overexpression correlates with cancer stage and confirmed Rac1b expression is associated with increased growth through enhancing NF-κB activity. Rac1b knockdown reduced cellular proliferation and reduced NF-κB activity. Surprisingly, Rac1b expression and NF-κB activity were upregulated in cells treated with chemotherapeutics, suggesting that Rac1b facilitates chemo-resistance through activation of NF-κB signaling. Knockdown of Rac1b or Rac inhibition increases the sensitivity of the cells to oxaliplatin. When used in combination, inhibition of Rac prevents the increase in NF-κB activity associated with chemotherapy treatment and increases the sensitivity of the cells to oxaliplatin. Although Rac inhibition or oxaliplatin treatment alone reduces the growth of colorectal cancer in vivo, combination therapy results in improved outcomes compared with single agents alone. We provide the first evidence that Rac1b expression confers resistance to chemotherapy in colorectal cancer. Additionally, we show that the use of a Rac inhibitor prevents chemoresistance by blocking activation of chemotherapy induced NF-κB signaling, providing a novel strategy to overcome resistance to chemotherapy in colorectal cancer.
Data from Efficacy of the Antibody–Drug Conjugate W0101 in Preclinical Models of IGF-1 Receptor Overexpressing Solid Tumors
Authors: Akla Barbara , Broussas Matthieu , Loukili Noureddine , Robert Alain , Beau-Larvor Charlotte , Malissard Martine , Boute Nicolas , Champion Thierry , Haeuw Jean-Francois , Beck Alain , Perez Michel , Dreyfus Cyrille , Pavlyuk Mariya , Chetaille Eric , Corvaia Nathalie
Published: April 2023

Abstract
The insulin-like growth factor type 1 receptor (IGF-1R) is important in tumorigenesis, and its overexpression occurs in numerous tumor tissues. To date, therapeutic approaches based on mAbs and tyrosine kinase inhibitors targeting IGF-1R have only shown clinical benefit in specific patient populations. We report a unique IGF-1R–targeted antibody–drug conjugate (ADC), W0101, designed to deliver a highly potent cytotoxic auristatin derivative selectively to IGF-1R overexpressing tumor cells. The mAb (hz208F2-4) used to prepare the ADC was selected for its specific binding properties to IGF-1R compared with the insulin receptor, and for its internalization properties. Conjugation of a novel auristatin derivative drug linker to hz208F2-4 did not alter its binding and internalization properties. W0101 induced receptor-dependent cell cytotoxicity in vitro when applied to various cell lines overexpressing IGF-1R, but it did not affect normal cells. Efficacy studies were conducted in several mouse models expressing different levels of IGF-1R to determine the sensitivity of the tumors to W0101. W0101 induced potent tumor regression in certain mouse models. Interestingly, the potency of W0101 correlated with the expression level of IGF-1R evaluated by IHC. In an MCF-7 breast cancer model with high-level IGF-1R expression, a single injection of W0101 3 mg/kg led to strong inhibition of tumor growth. W0101 provides a potential new therapeutic option for patients overexpressing IGF-1R. A first-in-human trial of W0101 is currently ongoing to address clinical safety.
Abstract 137: Epigenetic regulation of APOBEC3A mutagenesis and tumor evolution during targeted therapy in non-small cell lung cancer
Authors: Isozaki Hideko , Sakhtemani Ramin , Nikpour Naveed , Monroe Susanna , Lin Jessica , Sequist Lecia , Piotrowska Zofia , Gainor Justin , Buisson Rémi , Lawrence Michael , Hata Aaron
Published: April 2023

Acquired drug resistance to even the most effective anti-cancer targeted therapies remains an unsolved clinical problem. Although many drivers of acquired drug resistance have been identified, the underlying molecular mechanisms shaping tumor evolution during treatment are incompletely understood. We recently demonstrated that lung cancer targeted therapies commonly used in the clinic induce the expression of cytidine deaminase APOBEC3A (A3A), leading to sustained mutagenesis in drug tolerant cancer cells persisting during therapy. Preventing therapy-induced A3A mutagenesis by gene deletion decreased the accumulation of chromosomal aberrations and delayed the emergence of drug resistance. Thus, we hypothesize that inhibition of A3A may represent a potential therapeutic strategy to halt the evolution of resistant clones and prevent acquired resistance to lung cancer targeted therapies. Understanding the molecular mechanism of A3A induction during targeted therapy is a crucial step to develop targeting A3A therapies.Using a targeted drug combination screen, we found that DNA methyltransferase (DNMT) inhibitors induce expression of APOBEC3A in non-small cell lung cancer cells, phenocopying the effects of targeted therapies. RNA-seq profiling revealed that both targeted therapies and DNMT inhibitors increase expression of non-coding repeat RNAs. Repeatome analysis identified distinct classes of non-codding RNAs including endogenous retrovirus elements (ERV) in drug tolerant persister cells. Activation of endogenous intracellular viral sensing pathways by exogenous nucleic acids mimicking viral infection induced APOBEC3A, and genetic perturbation of RIG-I or MAVS reduced APOBEC3A induced by targeted therapy. These findings suggest that epigenetic derepression of retroviral repeat elements may underly APOBEC3A mutagenic activity and tumor evolution during lung cancer targeted therapy.

Citation Format: Hideko Isozaki, Ramin Sakhtemani, Naveed Nikpour, Susanna Monroe, Jessica Lin, Lecia Sequist, Zofia Piotrowska, Justin Gainor, Rémi Buisson, Michael Lawrence, Aaron Hata. Epigenetic regulation of APOBEC3A mutagenesis and tumor evolution during targeted therapy in 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 137.
Abstract 1775: Expansion of human T cells using xenogeneic free and gamma irradiated human platelet lysate
Authors: Alonso-Camino Vanesa
Published: April 2023

Commercially available human platelet lysate (hPL) is produced using expired human platelets obtained from accredited blood banks in the United States. These platelets were originally intended for use in patient transfusion. The safety of platelets used in transfusion is managed by the U.S. Food & Drug Administration (FDA), as well as the American Association of Blood Banks (AABB). These organizations set standards, including testing for transmissible diseases. The United States record for blood safety is well established, with extremely low rates of disease transmission, making the platelet units used for hPL manufacture low risk. The Covid-19 pandemic has increased awareness of emerging infectious diseases, even though transmission of Covid-19 via blood transfusion has not been documented. For that reason, gamma irradiated hPL offers an additional safety measure in the clinic. Chimeric Antigen Receptor (CAR) expressing T-cells have demonstrated potent clinical efficacy in patients with hematological malignancies. In addition, there are several phase I clinical trials evaluating the use of CAR-T-cells for targeting of solid tumor-associated antigens. Some of the challenging issues found during production of CAR-T cells are the efficiency of T cell transduction to generate CAR-T cells, the expansion of T cells to clinically relevant numbers and the long-term survival in vivo of the therapeutic cells. The use of human platelet lysate has been demonstrated to improve these issues. Our data from experiments performed using human CD3+ from donors demonstrates that human platelet lysates offer an improved performance on T cell expansion versus serum derived products. hPL efficiently promotes T cell expansion, with higher cell yields and lower cell exhaustion rate. Additionally, we efficiently developed a protocol for suspension culture of T cells, which could facilitate the large-scale expansion of allogeneic CAR-T cells.

Citation Format: Vanesa Alonso-Camino. Expansion of human T cells using xenogeneic free and gamma irradiated human platelet lysate [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 1775.
Abstract 1829: Generation of IL-21 INDUKINETM molecules for the treatment of cancer
Authors: Sullivan Jenna M. , Aderhold Pamela A. , Brodkin Heather R. , Economides Kyriakos , Hicklin Daniel J. , Ismail Nesreen , Lewis Yuka , Seidel-Dugan Cynthia , Spencer Cierra , Winston William M. , Salmeron Andres
Published: April 2023

In the past decade, great strides have been made in the development of novel immunotherapies, such as immune checkpoint inhibitors (ICI) to treat cancer. However, despite these improvements, subsets of patients do not respond to ICI, highlighting an unmet need for alternative immunotherapies. As potent immunomodulators, cytokines have been explored as treatments for cancer but have been limited due to toxicity and poor pharmacokinetics (PK). One of these key cytokines, interleukin 21 (IL-21), is a pluripotent cytokine that activates anti-tumor T cell responses, induces B cell activation, and promotes generation and maintenance of germinal centers and tertiary lymphoid structures. A member of the common γ-chain family of cytokines, IL-21 acts on a broader range of cells than IL-2 and does not induce vascular leak syndrome. Despite being a potent inducer of immune activation, clinical activity of IL-21 has been hampered by poor PK and adverse events at dose levels associated with efficacy. To explore the potential therapeutic benefits of IL-21 as a treatment for cancer, Werewolf Therapeutics has developed different formats of IL-21 INDUKINETM polypeptides containing native human IL-21, an inactivation domain and a half-life extension domain tethered together by protease sensitive linkers. IL-21 INDUKINETM polypeptides are peripherally inactive, but due to dysregulation of the protease milieu in the tumor microenvironment, upon dosing and distribution to the tumor, the linkers are cleaved and IL-21 is released intratumorally. We will present data demonstrating that IL-21 INDUKINETM polypeptides showed in vitro and in vivo inducibility and activity. In mouse syngeneic tumor models, the IL-21 INDUKINETM polypeptides showed improved tolerability and therapeutic window compared to equal molar dosing of a half-life extended IL-21 protein (IL-21-HLE). Mechanistically, IL-21 triggered a pronounced activation of the adaptive immunity in the tumor. Efficacy in these tumor models was linked to expansion and activation of tumor infiltrating T cells, increased polyfunctionality in CD8+ T cells, as well as signs of increased activation of B cells. Together, these data support continued exploration of an IL-21 INDUKINETM polypeptide as a therapy for cancer.

Citation Format: Jenna M. Sullivan, Pamela A. Aderhold, Heather R. Brodkin, Kyriakos Economides, Daniel J. Hicklin, Nesreen Ismail, Yuka Lewis, Cynthia Seidel-Dugan, Cierra Spencer, William M. Winston, Andres Salmeron. Generation of IL-21 INDUKINETM molecules for the treatment of 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 1829.
Abstract 1869: Preclinical evaluation of mosunetuzumab for the treatment of relapsed/refractory chronic lymphocytic leukemia
Authors: Barrett Kathy , Lu Kai , Jin Hyun Yong , Millen Rosie , Lefebure Marcus , Jiang Yanwen
Published: April 2023

Background: CD20 x CD3 T-cell engaging bispecific antibodies, such as Mosunetuzumab (Mosun), have shown promising efficacy in Non-Hodgkin’s lymphoma. However, their role in treating chronic lymphocytic leukemia (CLL) is still uncertain. CLL, a clonal disease of mature B cells, is associated with high B/T cell ratios and diminished T cell activation and function, including the inability to form strong immunosynapses (Ramsay et al, J Clinical Investigation, 2008). Herein, we explore whether Mosun could overcome these barriers and elicit strong T-cell mediated B-cell killing in CLL samples.

Methods: PBMCs from CLL patients and healthy donors were exposed to a titration of Mosun for 48 and 72 hours and analyzed for B cell death with flow cytometry. Markers of T cell activation and exhaustion were quantified in CD4 and CD8T cells and within their CD45RA/CCR7 subsets. The concentrations of secreted cytokines were measured by ELISA. To study the impact of high B/T ratio on B cell killing, B cells were isolated from healthy donor PBMC and added back to autologous PBMC to attain B/T ratios seen in CLL patient samples.

Results: After 48 hours with 0.04ug/ml Mosun, the percentage of dead B cells in healthy-donor samples (n=9) exceeded that in CLL samples (n=7) by four-fold (54.2 + 17.9 vs: 12.9 + 17.5%, p=0.0004). Under the same conditions, significantly more T cells expressed activation markers in healthy donors than in CLL patients, with 58.8 +17.1% of healthy donor CD8T cells expressing both CD69 and CD25 compared to and 31.4 +21.4% of CLL CD8T cells (p=0.013). The mean concentration of Granzyme B secreted by healthy donor samples upon Mosun treatment was over ten times higher than by CLL patient samples. Reconstitution of a healthy donor sample to a B/T ratio of 10 resulted in decreased B cell killing (29.7% dead B cells vs: 70.5% in un-reconstituted) without affecting T cell activation (62.9% CD69+CD25+ CD8T cells versus 56.2% in un-reconstituted).

Conclusions: Although single-agent Mosun treatment can activate T-cells in CLL patient samples and result in B-cell death, the response is suboptimal due to a number of factors, including deficient T cell activation and high B/T ratio. Ongoing work is focusing on evaluating drug partners to debulk CLL B cells or prime CLL T cells for better B-cell killing by Mosun.

Citation Format: Kathy Barrett, Kai Lu, Hyun Yong Jin, Rosie Millen, Marcus Lefebure, Yanwen Jiang. Preclinical evaluation of mosunetuzumab for the treatment of relapsed/refractory chronic lymphocytic leukemia [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 1869.
Abstract 2265: STING pathway activation by ATR inhibition potentiates the antitumor immune response to anti-PD-L1 antibody in small cell lung cancer
Authors: Sen Triparna
Published: April 2023

Introduction: Small cell lung cancer (SCLC) is the most aggressive subtype of lung cancer, with a very poor prognosis and limited therapeutic options. Recent clinical trials of immune checkpoint blockade (ICB) combined with chemotherapy delivered only very modest benefit. Here, we identified that ataxia telangiectasia and rad3 related (ATR), the primary activator of the replication stress response, is highly enriched in SCLC and inhibition of ATR induced DNA damage and apoptosis in multiple SCLC models.

Methods: In this study, we performed genetic and pharmacological inhibition of ATR in a panel of human and murine SCLC models. Furthermore, we investigated the effect of ATR inhibition either alone or in combination with PD-L1 blockade either as a first-line or a second-line treatment in multiple immunocompetent mouse models of SCLC. The downstream effects of ATR inhibition was assessed by single-cell RNA sequencing, multicolor flow cytometry, western blot analysis, IHC, and genomic analysis.

Results: In multiple immunocompetent SCLC mouse models, ATR inhibition (ATRi) remarkably enhanced the anti-tumor effect of PD-L1 blockade both as first- and second-line treatment regimen. Targeting ATR activated the cGAS/STING pathway, induced the expression of Type I and II interferon pathways, and caused significant infiltration of cytotoxic and memory/effector T-cells into tumors. Interestingly, ATRi also led to significant induction of MHC class I in SCLC in vitro and in vivo models. Analysis of pre- and post-treatment clinical samples from a proof-of-concept study of a first-in-class ATR inhibitor, M6620 (VX970, berzosertib), and TOP1 inhibitor topotecan, in patients with relapsed SCLCs validated the induction of MHC class I and interferon pathway genes, for the first time in this disease.

Conclusion: Our findings highlight ATRi as a potentially transformative vulnerability of SCLC, paving the way for combination clinical trials with anti-PD-L1. Given the increasing importance of immunotherapy for the management of SCLC and that ATR inhibitors are already in clinical trials, combining an ATR inhibitor with PD-L1 blockade may offer a particularly attractive strategy for the treatment of SCLC and contribute to the rapid translation of this combination into the clinic.

Citation Format: Triparna Sen. STING pathway activation by ATR inhibition potentiates the antitumor immune response to anti-PD-L1 antibody in 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 2265.
Abstract 2395: A bioluminescent probe for detection and imaging of heparanase enzymatic activity
Authors: Somers Johnathan , Schleyer Kelton , Liu Jun , Wang Zhishen , Kafle Arjun , Cui Lina
Published: April 2023

Cancers of all types have been shown to overexpress the carbohydrate-processing enzyme heparanase during angiogenesis and invasion, and this enzymatic activity correlates positively with tumor stage and the presence of metastases. While detection of heparanase enzymatic activity holds potential for cancer diagnosis and staging, no probe has been achieved for in vivo systems. We have recently developed fluorogenic heparanase probes for single-step detection of in vitro heparanase enzymatic activity, drastically simplifying the detection of heparanase activity. The modular chemistry allows us to extend the utility further to improve the sensitivity of in vitro heparanase activity detection and enable in vivo detection. Thus, we have developed a bioluminescent heparanase probe, which upon activation by heparanase produces a substrate of firefly luciferase, a standard reporter enzyme for in vivo monitoring of tumor progression. This probe will be validated in multi-well assays of heparanase activity, and applied in real-time correlation of heparanase activity and tumor progression in, fLuc+ tumors in animal models. These studies hold promise in enabling highly sensitive detection of heparanase activity both in vitro and in vivo, and in allowing future research of real-time monitoring of heparanase activity with the tumor progression.

Citation Format: Johnathan Somers, Kelton Schleyer, Jun Liu, Zhishen Wang, Arjun Kafle, Lina Cui. A bioluminescent probe for detection and imaging of heparanase enzymatic activity [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 2395.
Abstract 2586: OncogenicPIK3CA promotes hematopoietic reprogramming and cell transdifferentiation developing hematopoietic malignancy
Authors: Kozurek Emma , Dickerson Erin B. , Kim Jong Hyuk
Published: April 2023

PIK3CA mutation is one of the most common, recurrent genetic abbrations identified across multiple types of cancers. Such mutations sustain activation of PI3K/AKT/mTOR pathway, being considered reliable therapeutic targets; yet, the functional consequences still remain unclear. Angiosarcomas are a heterogenous group of soft-tissue sarcomas that form malignant endothelium with disorganized, irregular blood-filled vascular spaces, and a subset of the vascular tumors harbor PIK3CA mutations. In this study, we found that one of 11 canine angiosarcoma cells gave rise to vascular tumors in 3 of 3 mice in a series of xenograft experiments using a total of 86 immunodeficient BNX mice. Intriguingly, we also observed that xenografts developed lymphoproliferative tumors indicating a mouse B-cell origin in 3 of 4 mice from one case of canine patient-derived tumor xenografts: four tumor cases surgically implanted in a total of 16 BNX mice. Additionally, canine angiosarcoma cells induced splenomegaly with expansion of Ter-119+ erythroid progenitors in NSG mice. Canine angiosarcoma cells (two cell lines; DHSA-1426 and EFB) were capable of hematopoietic expansion and cell lineage differentiaton in vitro. Since PIK3CA mutations appear to promote cellular stemness and impairment of cell lineage differentiation, we determined if the mutations play a role in hematopoietic regulations of angiosarcoma cells. DHSA-1426 angiosarcoma cells were used to induce PIK3CA H1047R mutations using CRISPR/Cas9. We found that PIK3CA mutant angiosarcoma cells dysregulated AKT, ERK, and mTOR pathway with enrichement of inflammatory cytokines such as IL-6, IL-8, and MCP-1. Single cell RNA-seq data showed that PIK3CA mutant angiosarcoma cells established distinct single cell clusters representing immune reactions, cellular stemness, and lineage differentiation. Furthermore, PIK3CA mutant angiosarcoma cells developed malignant hematopoietic tumor in one of five BNX mice, while no evidence of hematopoietic tumor formation was found in mice transplanted with non-mutant cells. Altogether, our data suggest that angiosarcoma cells have the capacity to promote hematopoietic imbalance impacting on cellular ontogeny and lineage differentiation, potentially mediated by oncogenic PIK3CA. Our ongoing work is determining the mechanism of the cell fate decisions using bi-potential hematoendothelial progenitors derived from induced pluripotent stem cells harboring oncogenic PIK3CA.

Citation Format: Emma Kozurek, Erin B. Dickerson, Jong Hyuk Kim. OncogenicPIK3CA promotes hematopoietic reprogramming and cell transdifferentiation developing hematopoietic malignancy [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 2586.
Abstract 2669: RRM2 inhibition synergizes with PARP inhibitor in ovarian cancer cells
Authors: Chen Chi-Wei
Published: April 2023

The use of Poly(ADP-ribose) polymerase inhibitors (PARPi) has been applied for the treatment of epithelial ovarian cancer (EOC) patients with homologous recombination (HR)-deficient disease, such as BRCA1/2 mutations. However, 40 - 70% of patients do not initially respond to PARPi in ovarian cancer with non-BRCA mutations, and acquired resistance has been demonstrated clinically. Ribonucleotide reductase (RNR, which consists of two RRM1 subunits and two RRM2 subunits) is the rate-limiting enzyme in the biosynthesis of dNTPs for DNA replication and DNA damage repair. As targeting RRM2 has been applied for many cancer therapies clinically or in clinical trials, this study hypothesizes that the inhibitory of RRM2 arguments PARPi potency against ovarian cancer. To this goal, this study evaluates the therapeutic effects of RRM2 inhibitor Osalmid (a resveratrol analog) alone or combined with PARPi by employing a panel of ovarian cancer cell lines using SRB assay. The effects on apoptosis and cell-cycle arrest were analyzed using flow cytometry. The cellular thermal shift assay was conducted to explore if Osalmid interacts with RRM2. DNA double strand break marker, ϒH2AX, was detected in compound-treated cells using Western blot. The results provide a new synthetic lethality by combining RRM2 inhibitor and PARPi. The combination induced apoptosis and caused the cell-cycle arrest. The results show that Osalmid binds to RRM2 directly. This study provides both a novel RRM2 inhibitor from a natural compound and a new understanding of the dNTP metabolic demands and may lead to urgently-needed strategies for the treatment of ovarian cancer.

Citation Format: Chi-Wei Chen. RRM2 inhibition synergizes with PARP inhibitor in ovarian 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 2669.
Abstract 2757: Combination of a fluorescent substrate-based MMP activity assay and hit pick reading/imaging procedure to screen for inhibitors of MT1-MMP activity and 3D glioma tumoroid invasion
Authors: Larson Brad , Fields Gregg , Knapinska Ania
Published: April 2023

Malignant and nonmalignant brain tumors are composed of a group of more than 100 different types. Malignant gliomas, including glioblastoma multiforme (GBM) and astrocytomas, are the most common primary brain tumors in the United States, and make up 78% of malignant brain tumors. Membrane type 1 matrix metalloproteinase (MT1-MMP) has been shown to be crucial for the progression, invasion, migration, and angiogenesis of tumors. Use of a FRET substrate to quantify MT1-MMP activity, where tumoroids are embedded in a collagen hydrogel, would simplify detection of potential protease inhibitors, while using an in vivo-like cell model. In the present study, multiple glioma cell lines were formed into tumor spheroids, followed by type I collagen addition. Many known MT1-MMP inhibitors were then added to the wells, to potentially inhibit invasion of the 3D cell models. The substrate and experimental setup were then combined with the joint reading and imaging process available in the Agilent BioTek Gen5 microplate reader and imager software, to create a hit pick screening method. During the procedure, all control and test wells were read, and the signal from cleaved substrate was quantified. Uninhibited invasion within positive control wells exhibited high fluorescence values. Therefore, a hit pick criterion was established such that any wells containing test molecules that were statistically lower than average in fluorescent signal from the corresponding positive control, which should exhibit inhibited invasion, were imaged. Wells that were not significantly lower were not imaged. The result was a screening method which increased efficiency by reducing image capture time and storage requirements.

Citation Format: Brad Larson, Gregg Fields, Ania Knapinska. Combination of a fluorescent substrate-based MMP activity assay and hit pick reading/imaging procedure to screen for inhibitors of MT1-MMP activity and 3D glioma tumoroid invasion [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 2757.
Abstract 276: Delineating the role of vesicular glutamate transporter SLC17A7 in osteosarcoma
Authors: Nerlakanti Niveditha , McGuire Jeremy , Bishop Ryan T. , Yu Diana , Reed Damon R. , Lynch Conor C.
Published: April 2023

Osteosarcoma (OS) frequently metastasizes to lung where it greatly contributes to patient mortality. Frustratingly, OS treatment options have remained static due to a paucity of strong pre-clinical evidence to motivate clinical trials. To identify therapeutic targets, we assessed a number of FDA approved therapies for their cytotoxic effects. We found that histone deacetylase (HDAC) inhibitors (panobinostat and romidepsin) limited OS viability at low nM and were highly effective for the treatment of lung metastatic disease in vivo. Although clinically approved, HDAC inhibitors have noted toxicities. Therefore, we next examined the potential mechanisms through which HDAC controlled OS growth. Gene expression analyses on romidepsin treated OS cells revealed key up and downregulated targets. We found that SLC17A7, a vesicular glutamate transporter, was highly and consistently induced in response to romidepsin (greater than 100 fold more than base line) across multiple OS cell lines. Functionally, SLC17A7 traps glutamate in cytoplasmic synaptic vesicles that are then released via exocytosis. Our data show that HDAC inhibition reduces glutamate secretion from OS cells while SLC17A7 overexpression significantly impaired OS viability. Further, we showed that the glutamate export inhibitor, riluzole, significantly impairs the OS growth in vitro and is highly effective for the treatment of lung metastatic OS in vivo. Taken together, we conclude that HDAC1/2 suppression of SLC17A7 ensures high cytoplasmic glutamate levels that can be leveraged for OS growth. We posit that targeting glutamate usage by OS cells using FDA approved inhibitors such as riluzole will be highly effective for the treatment of lung metastatic OS.

Citation Format: Niveditha Nerlakanti, Jeremy McGuire, Ryan T. Bishop, Diana Yu, Damon R. Reed, Conor C. Lynch. Delineating the role of vesicular glutamate transporter SLC17A7 in osteosarcoma [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 276.
Abstract 3075: Enhanced efficacy of ARV-471, a novel PROTAC® estrogen receptor degrader, in combination with targeted agents in estrogen receptor-positive (ER+) breast cancer models
Authors: Teh Jessica , Bortolon Elizabeth , Pizzano Jennifer , Pannone Melissa , Landrette Sean , Gedrich Richard , Taylor Ian
Published: April 2023

ARV-471 is a selective, orally bioavailable PROteolysis-TArgeting Chimera (PROTAC®) small molecule that induces wild-type and mutant estrogen receptor (ER) alpha degradation via the ubiquitin-proteasome system. ARV-471 demonstrates superior ER degradation and antitumor activity compared to fulvestrant in endocrine sensitive and resistant xenograft models and has shown significant ER degradation and promising clinical benefit in late-line ER+ breast cancer patients. Dual pathway inhibition combining ER targeting agents with CDK4/6 or PIK3CA/mTOR pathway inhibitors is now a central strategy for treatment of advanced ER+ breast cancer. However, resistance to aromatase inhibitors resulting from ESR1 gene mutations, suboptimal ER degradation and the intramuscular route of administration of fulvestrant underscore a need for superior orally bioavailable endocrine therapy backbones for these combinations. Here, we assessed the effects of ARV-471 in combination with CDK4/6 or PIK3CA/mTOR pathway inhibitors in preclinical models of ER+ breast cancer. In vitro studies revealed evidence of synergistic interactions between ARV-471 and the CDK4/6 inhibitors abemaciclib and ribociclib, the mTOR inhibitor everolimus, or the PIK3CA inhibitors alpelisib and inavolisib in ER+ breast cancer cells. Evidence of synergistic effects between ARV-471 and everolimus was also observed in ER+ breast cancer cells expressing ER Y537S or D538G mutations. ARV-471 in combination with CDK4/6, PIK3CA or mTOR inhibitors led to tumor regressions in MCF7 xenografts when compared to single agents alone. ARV-471 also displayed greater anti-tumor activity in combination with abemaciclib, ribociclib or inavolisib than that observed with fulvestrant in combination with these agents. Taken together, these data suggest the potential utility of ARV-471 as a combination partner for clinically relevant targeted agents for treatment of early and late-stage ER+ disease.

Citation Format: Jessica Teh, Elizabeth Bortolon, Jennifer Pizzano, Melissa Pannone, Sean Landrette, Richard Gedrich, Ian Taylor. Enhanced efficacy of ARV-471, a novel PROTAC® estrogen receptor degrader, in combination with targeted agents in estrogen receptor-positive (ER+) breast cancer 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 3075.
Abstract 3243: Modulating the brain immune system to fight cancer in 3 dimensions
Authors: Yeini Eilam , Vaskovich-Koubi Daniella , Kleiner Ron , Florindo Helena F. , Satchi-Fainaro Ronit
Published: April 2023

Despite the remarkable efficiency of immune checkpoint modulators against primary and metastatic brain neoplasms, there is a low percentage of responders and clinical trials report severe immune-mediated side effects and disease relapse. An accumulated body of evidence show that non-tumor cells within the tumor microenvironment (TME), specifically the brain microenvironment (BME), including tumor vasculature and immune stromal cells, such as astrocytes, microglia and pericytes, dictate the overall therapeutic efficacy. We synthesized a biodegradable, off-the-shelf and cost-effective nano-sized polymeric platform that combines a cancer vaccine with the targeted inhibition of molecular and/or cellular immune suppressive players. These precision nano-sized medicines aim to re-educate and harness patient T-cell response against tumors, leading to an immunological memory able to control tumor relapse without any follow-up treatment. The design of these advanced peptide and RNA immunotherapeutics is guided by the identification of lead immune suppressor factors and tumor-specific antigens and proinflammatory cytokines using novel 3D bio-printed brain tumor-immune models developed in our lab. Using this unique model platform we identified P-selectin as a novel immune checkpoint in the brain regulating cancer cells-microglia and tumor-associated macrophages interactions. Combining a P-selectin inhibitor with our first nano-immunotherapy candidates sensitized brain malignancies mouse models to immune-checkpoint modulators, dramatically increasing disease-free survival rates.

Citation Format: Eilam Yeini, Daniella Vaskovich-Koubi, Ron Kleiner, Helena F. Florindo, Ronit Satchi-Fainaro. Modulating the brain immune system to fight cancer in 3 dimensions [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 3243.