bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 6530: TREM1 inhibition: A novel approach to suppress tumor growth and enhance immune checkpoint therapy
Authors: Ajith Ashwin , Moamouni Kenza , Horuzsko Daniel D , Horuzsko Anatolij
Published: March 2024

In the context of cancer, inflammation is a multifaceted contributor to tumorigenesis. The Triggering Receptor Expressed on Myeloid Cells 1 (TREM1) is recognized for its role in amplifying inflammatory responses, yet its specific pro-tumorigenic mechanisms have remained elusive. This study employs Trem1-deficient mice and a novel inhibitor, VJDT, to explore the therapeutic potential of targeting TREM1 in cancer. Both genetic silencing and pharmacological inhibiton of Trem1 led to remarkable reductions in tumor growth in mouse models of melanoma (B16F10) and fibrosarcoma (MCA205). In-depth analysis using single-cell RNA sequencing unveiled that TREM1 deficiency resulted in a decrease in the frequency and suppressive capabilities of myeloid-derived suppressor cells (MDSCs) within the tumor microenvironment, concomitant with an increase in cytotoxic CD8+ T cells and enhanced T cell activation. Furthermore, TREM1 inhibition not only curtailed tumor growth but also potentiated the effectiveness of anti-PD-1 therapy, primarily by mitigating MDSC frequency and reversing T cell exhaustion. Notably, in melanoma xenografts from patient samples, pharmacological TREM1 inhibition via VJDT treatment significantly downregulated critical oncogenic pathways linked to cell proliferation, migration, and survival. This research underscores the pivotal role of TREM1, expressed both within cancer cells and the tumor microenvironment, in driving cancer progression. Consequently, targeting TREM1 for therapeutic intervention holds promise for reshaping the immunosuppressive tumor milieu and augmenting the success of immune checkpoint therapy.

Citation Format: Ashwin Ajith, Kenza Moamouni, Daniel D Horuzsko, Anatolij Horuzsko. TREM1 inhibition: A novel approach to suppress tumor growth and enhance immune checkpoint therapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6530.
Abstract 6531: Anti-tumor immune function of NR2F6, an orphan nuclear receptor, in stromal cells
Authors: Kim Hyungsoo , Feng Yongmei , Radaeva Marria , Sergienko Eduard , Cherkasov Artem , Ronai Ze'ev A.
Published: March 2024

Growing evidence points to the importance of the tumor microenvironment (TME) in tumor growth control, progression, and therapy response. Among those is the greater understanding of immune system components within the TME as mediators of tumor growth control. NR2F6 is an orphan nuclear receptor, which was shown to serve as an immune intrinsic checkpoint component and has been suggested to elicit tumor-intrinsic suppression of anti-tumor immunity. Correspondingly, genetic depletion of NR2F6 in CD8 T cells abrogates the immune-activating cytokines (e.g., IL-2, IFNg). In addition, genetic ablation of NR2F6 in melanoma cells activates CD8 T cell-mediated anti-tumor immunity partly by suppressing the expression of tumor-intrinsic immune repressors NACC1 and FKBP10. Notably, combined genetic ablation of tumor cells (NR2F6 KO melanoma) and stroma cells (NR2F6 KO mouse) resulted in a more pronounced inhibition of tumor growth compared with ablation of either tumor cells or TME. The latter provides the foundation for screening NR2F6 inhibitors, which are expected to have a strong systemic (tumor inhibition and immune cell activation) effect on tumor growth. Interestingly, single-cell transcriptomic data from human tumors identified high expression of NR2F6 in stroma cells, cancer-associated fibroblasts (CAFs), and tumor-associated endothelial cells (TAEs). Consistent with these, scRNAseq analysis of mouse melanoma revealed higher expression of NR2F6 in SMA+ immune suppressive myo-CAFs than in immune activating CAFs. Studies that directly reveal the role of stromal NR2F6 in anti-tumor immunity and tumor growth and the state of NR2F6 inhibitors will be discussed.

Citation Format: Hyungsoo Kim, Yongmei Feng, Marria Radaeva, Eduard Sergienko, Artem Cherkasov, Ze'ev A. Ronai. Anti-tumor immune function of NR2F6, an orphan nuclear receptor, in stromal cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6531.
Abstract 6546: Spatial immunology landscapes that correlate with survival in triple negative breast cancer
Authors: Foroughi pour Ali , Martinek Jan , Wu Te-Chia , Sivajothi Santhosh , Liu Zichao , Zhou Jie , Rimm David , Robson Paul , Bates Katherine , Palucka Karolina , Chuang Jeffrey H.
Published: March 2024

Triple negative breast cancer (TNBC) is an aggressive subtype of breast cancer characterized by negative immunohistochemistry staining for estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2). Treatment options for TNBCs are limited due to lack of tumor-specific targeted therapies, resulting in poor prognosis and patient survival. This is exacerbated by lack of prognostic markers of response. While current studies suggest tumor immune interactions are important, current immune activity quantifications, such as scores quantifying abundance of tumor-infiltrating lymphocytes (TILs), are not sufficient to define tumor immune status. We used imaging mass cytometry (IMC) to measure 33 markers on primary tumors of 100 patients undergone chemotherapy with long-term follow-up to explore the tumor immune microenvironment of TNBCs. Concordant with previous studies, a higher ratio of T-cells was associated with response to chemotherapy and longer overall survival (adjusted p-value<0.05). Moreover, using Kmeans clustering we identified 13 distinct cellular neighborhoods, reflective of the heterogenous nature of TNBCs. Among others, we identified a neighborhood, characterized by low CD14+ expression, low cytokeratin, high vimentin expression and high CD45RO, that contributes highest impact on correlation with overall survival (adjusted p-value<0.01). These results suggest an important role for memory T cells in the stroma. Thus, resolving spatial organization of the tissue is important to understanding patient response to therapy in TNBCs.

Citation Format: Ali Foroughi pour, Jan Martinek, Te-Chia Wu, Santhosh Sivajothi, Zichao Liu, Jie Zhou, David Rimm, Paul Robson, Katherine Bates, Karolina Palucka, Jeffrey H. Chuang. Spatial immunology landscapes that correlate with survival in triple negative breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6546.
Abstract 656: A novel dual-targeting peptide HS1002 enhances anti-tumor activity via GnRH/human telomerase reverse transcriptase (hTERT) interaction in human prostate cancer cells
Authors: Park Jae Hyeon , Kim Ju Ri , Cha Hwa Young , Kim Hyung Sik
Published: March 2024

Human telomerase reverse transcriptase (hTERT) is overexpressed in most human cancers. hTERT is considered as an important target for cancer therapy. In the present study, a new peptide HS1002 were synthesized with sequence of pGlu-His-Trp-Ser-Tyr-Arg-Leu-Arg-Phe-Ile-Pro-NHEt based on the GnRH agonist and hTERT. The aim of this study was to evaluate HS1002 for its anticancer activity by dual-targeting to GnRH/hTERT in prostate cancer cells. Upon comparison with different prostate cancer cell lines, HS1002 exhibited highest cytotoxicity against LNCaP cells. The hTERT expression correlated with telomerase activity in LNCaP cells, was significantly inhibited by HS1002, resulting in reduction of proliferation, metastasis and increase in apoptosis. Additionally, HS1002 suppressed c-Myc and AKT/ERK pathway in LNCaP cells. In the tumor-bearing nude mice model, HS1002 significantly inhibited tumor growth and downregulated the expression of hTERT and Ki-67 in tumor tissue as evidenced by western blot and immunohistochemistry analysis, respectively. Moreover, repeated subcutaneous injection of HS1002 resulted in the reduction of both serum testosterone levels and seminal vesicle weight. HS1002 also increased cytosolic calcium influx and CRE-luciferase activity in GnRHR-overexpressing HEK293 cells compared to mock-transfected transfected cells. Furthermore, a potent cytotoxicity in LNCaP cells was exhibited by HS1002-activated peripheral blood mononuclear cell (PBMC) with interleukin (IL)-2 using LDH release assay. In addition, a flow-cytometric analysis confirmed an elevation in the production of granzyme B and IFN-γ in CD8+ T cells in the MC38 syngeneic mouse model by HS1002. These data indicate that the inhibition of hTERT expression by HS1002 suppresses prostate cancer cell growth and induced anti-cancer immunity. Therefore, HS1002 might be used as a novel therapeutic drug for prostate cancer.

Citation Format: Jae Hyeon Park, Ju Ri Kim, Hwa Young Cha, Hyung Sik Kim. A novel dual-targeting peptide HS1002 enhances anti-tumor activity via GnRH/human telomerase reverse transcriptase (hTERT) interaction in human prostate cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 656.
Abstract 6577: Chemoproteomic evaluation of PROTACs targeting estrogen receptor alpha for ER+ breast cancer
Authors: Sandusky Zachary , Brown Myles
Published: March 2024

In our investigation of estrogen receptor (ER) targeted protein degraders for advanced ER+ breast cancer, we assessed three proteolysis targeting chimeras (PROTACs), ARV471, ERD308, and ERD3111. Global proteomic analysis unveiled off-target protein degradation of progesterone receptor (PR) and phosphodiesterase 6D (PDE6D) by ER targeted PROTACs, but not selective ER degraders (SERDs). PR and PDE6D have previously been implicated as targets in cancer treatment. Protein degradation is rescued in CRBN- or VHL-knockout cells. Co-treating ER+ breast cancer cells with ligands for PR or PDE6D outcompeted PROTAC-mediated degradation and stabilized the respective protein, demonstrating the PROTACs are targeting the PR and PDE6D ligand-binding domains. Competition assays in ER-negative cell lines confirmed PR and PDE6D protein degradation is ER-independent. These findings underscore the importance of understanding off-target effects for developing more selective and effective therapeutics in ER+ breast cancer.

Citation Format: Zachary Sandusky, Myles Brown. Chemoproteomic evaluation of PROTACs targeting estrogen receptor alpha for ER+ breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6577.
Abstract 6592: Deciphering the effects of age on T cell immunity and immunotherapy
Authors: Han SeongJun , Georgiev Peter , Schneider Jaime , Huang Amy , Nugmanova Zhanel , Nguyen Thao H. , Yao Conghui , Johnson Sheila , Joshi Shakchhi , Dhiman Ishita , Drijvers Jefte M. , Fung Megan , Rowe Jared H. , Miller Brian C. , Freeman Gordon J. , Ringel Alison E. , Haigis Marcia C. , Sharpe Arlene H.
Published: March 2024

Aging induces profound alterations in host biology and correlates with unfavorable clinical outcomes in age-related diseases such as cancer. While the pivotal role of the immune system in regulating tumor progression is well-acknowledged, the precise mechanisms through which aging influences anti-tumor T cell immunity and responsiveness to immune checkpoint blockade (ICB) remain elusive. In this study, we employed syngeneic murine tumor models (B16, MC38, and E0771) in young (2-4 months) and aged (20-24 months) cohorts to elucidate the early impacts of aging on tumor development and T cell responses. Our findings demonstrate that aged mice exhibit accelerated tumor growth across various models. In-depth analysis of tumor-infiltrating lymphocytes (TILs) uncovered distinct alterations in the CD8+ T cell population, characterized by decreased activation status and diminished tumor specificity in aged mice. Correspondingly, aged mice exhibited resistance to anti-PD-1 immunotherapy. To unravel the underlying environmental factors contributing to compromised anti-tumor T cell responses and ICB resistance, we characterized the immune and metabolic landscapes of the aged tumor-draining lymph nodes and tumors. Furthermore, we established a genetically engineered mouse model of lung adenocarcinoma in both young and aged mice, unveiling novel functions and mechanisms associated with age-related T cells actively impeding effective tumor control. In the context of increasing average life expectancy, comprehending the intricate interplay between age-related T cell dysfunction and cancer assumes paramount importance. Such insights hold the key to the development of innovative therapeutic strategies tailored for the growing population of older patients.

Citation Format: SeongJun Han, Peter Georgiev, Jaime Schneider, Amy Huang, Zhanel Nugmanova, Thao H. Nguyen, Conghui Yao, Sheila Johnson, Shakchhi Joshi, Ishita Dhiman, Jefte M. Drijvers, Megan Fung, Jared H. Rowe, Brian C. Miller, Gordon J. Freeman, Alison E. Ringel, Marcia C. Haigis, Arlene H. Sharpe. Deciphering the effects of age on T cell immunity and immunotherapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6592.
Abstract 6595: HDAC8 targeting impairs Foxp3+Treg cell function and promotes anti-tumor immunity
Authors: Kong Fanhua , Wang Liqing , Beeler Aaron , Hancock Wayne W.
Published: March 2024

HDAC8 is an evolutionarily distinct, X-linked, zinc-dependent class I histone/protein deacetylase implicated in developmental disorders, parasitic infections, myopathy, and cancers such as neuroblastoma, gastric cancer, hepatocellular carcinoma, oral squamous cell carcinoma, and childhood acute lymphoblastic leukemia. Here, we highlight a hitherto unknown role of HDAC8 in immune cells by presenting data on conditional targeting of HDAC8 in T cells and the effects of selective HDAC8 inhibitors (HDAC8i) on T cell-dependent immune responses. First, as a genetic approach, we produced C57BL/6 mice with floxed exon 3 of the HDAC8 gene suitable for targeted deletion of HDAC8 and, after crossing with syngeneic CD4cre mice, demonstrated conditional deletion of HDAC8 and enhanced acetylation of SMC3, a classic HDAC8 substrate, in their T-cells. Next, in a pharmacologic approach, we tested isoform-selective inhibitors of HDAC8 (OJ-1, PCI-34051) and assessed effects on Foxp3+ T-regulatory (Treg) cell suppressive function. Finally, we performed flow cytometry, RNAseq, CHIP-seq and mass spectrometry to investigate the underlying mechanisms by which HDAC8 knockout affected Treg function. Our data demonstrate that knocking down or inhibiting HDAC8: (i) impaired murine Treg suppressive function in vitro and in vivo, including inhibiting the ability of Tregs to promote mouse cardiac allograft survival (p<0.01); (ii) decreased Treg function in homeostatic proliferation assays (p<0.01), e.g., involving adoptive transfer of WT or HDAC8-/- Tregs plus WT conventional T cells into immunodeficient hosts; (iii) decreased intratumoral Tregs, increased CD4 and CD8 T cells, increased production of effectors such as IFN-g and granzyme-B, and limited growth of syngeneic mouse non-small cell lung cancer cell lines (p<0.01) (whereas no effect of Hdac8i on tumor growth was seen in immunodeficient hosts, indicating the key action was via immune cell targeting). Mechanistically, HDAC8 co-precipitated with Foxp3 and NFAT5 and promoted the deacetylation of Foxp3 and NFAT5, and knockout of HDAC8 enhanced the acetylation level of NFAT5 and promoted cytokine expression. Hence, our combined genetic and pharmacologic studies establish the importance of HDAC8 in Foxp3+ Treg cells and show that therapy with selective HDAC8 inhibitors can be a novel therapeutic approach in immuno-oncology.

Citation Format: Fanhua Kong, Liqing Wang, Aaron Beeler, Wayne W. Hancock. HDAC8 targeting impairs Foxp3+Treg cell function and promotes anti-tumor immunity [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6595.
Abstract 6598: Inhibition of cGAS as a strategy to restore anti-tumor immunity response to STING agonist in chromosomally unstable tumors
Authors: Hong Christy , Caprio Lindsay , Duran Mercedes , Rogava Meri , Ling Hsiang-His , Gurrapu Sreeharsha , Ebel Leon , Di Bona Melody , Izar Benjamin , Bakhoum Samuel F.
Published: March 2024

The activation of STING (stimulator of interferon genes) has been widely shown to induce signaling pathways, triggering type I interferon and ultimately generating anti-tumor immunity. Whereas initial preclinical studies on STING agonists exhibited boost in anti-tumor response, clinical trials combining STING agonist and immune checkpoint blockade agent PD-1 reported that only small subset of patients benefited from the treatment. This study highlights a potential key mechanism underlying the lack of benefit from STING agonist observed in most clinical trial patients. We reveal a phenomenon known as chromosomal instability (CIN), characterized by persistent chromosome segregation errors over multiple rounds of mitosis, drives chronic activation of cGAS (cyclic GMP‒AMP synthase) through continuously supplying its substrate in the form of micronuclei. Chronic activation of cGAS stimulates degradation of its downstream target STING in a feedback-loop manner. This consequently attenuates type I interferon signaling upon STING activation, blunting its anti-tumor response. Remarkably, we show suppression of CIN, achieved through introduction of mitotic centromere-associated kinesin (MCAK), or inhibition of cGAS activity, either by pharmacological agent or total genetic ablation of cGAS using CRISPR-Cas9, restores type I interferon production and anti-tumor immunity upon the administration of STING agonist, MSA-2 in four of the five advanced tumor models. Furthermore, we show this restoration of type I interferon signaling and anti-tumor immunity is cancer cell STING-dependent as genetic deletion of STING in the tumor cells nullifies this effect. In summary, we provide a mechanistic insight underlying the limited anti-tumor response observed in STING agonist trials and propose potential strategies, through finetuning of CIN level or inhibition of cGAS activity, to illicit stronger anti-tumor immunity in combination with STING agonist treatment.

Citation Format: Christy Hong, Lindsay Caprio, Mercedes Duran, Meri Rogava, Hsiang-His Ling, Sreeharsha Gurrapu, Leon Ebel, Melody Di Bona, Benjamin Izar, Samuel F. Bakhoum. Inhibition of cGAS as a strategy to restore anti-tumor immunity response to STING agonist in chromosomally unstable tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6598.
Abstract 6611: Unbiased functional genetic screens reveal essential RNA modifications in human cancer and drug resistance
Authors: Pauli Cornelius , Kienhöfer Michael , Müller-Tidow Carsten , Frye Michaela
Published: March 2024

RNA modification pathways are mis-regulated in multiple types of human cancer. To comprehensively identify cancer-relevant RNA modifications and their regulators, we screened all 150 annotated human RNA modifying proteins across 18 different normal and cancer cell lines using a CRISPR-based genetic knockout system. Fifty RNA modifying proteins were essential for survival of at least one cell type. A third of these essential genes were amplified in 38 different human primary cancer types and potentially drive cancer growth. Unexpectedly, the number of essential genes per cell line varied considerably, and this variation was not due to tissue of origin. Instead, we found that cancer cell-specific mitochondrial metabolic plasticity was responsible for the unique requirement of certain RNA modifications. For example, leukemia cells with high intrinsic drug tolerance required mitochondrial flexibility to survive treatment with the anti-leukemic drugs cytarabine and venetoclax. Synthetic lethality screens revealed that drug-resistance is abolished by deleting the mitochondrial methyltransferase TRMT5, which is responsible for the formation of N1-methylguanosine (m1G) in the tRNA anticodon loop. In summary, our study identifies cancer-relevant RNA modifying enzymes, and reveals a novel promising drug target for therapy-resistant acute myeloid leukemia.

Citation Format: Cornelius Pauli, Michael Kienhöfer, Carsten Müller-Tidow, Michaela Frye. Unbiased functional genetic screens reveal essential RNA modifications in human cancer and drug resistance [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6611.
Abstract 662: Vitamin B1 derivative, fursultiamine, prevents lung cancer cells growth
Authors: Boekweg Noah , Powers Ryan , Ramana Kota
Published: March 2024

Lung cancer is the leading cause of cancer death in men and the second leading cause of cancer death in women worldwide. Cigarette smoke-induced oxidative and inflammatory responses are the major risk factors for the development of lung cancer. Several compounds have been tested for their efficacy in preventing lung cancer. However, very few compounds have gone through clinical studies. We hypothesize that with its potent anti-oxidative and anti-inflammatory actions, fursultiamine, a disulfide lipid-soluble derivative of vitamin B1 (thiamine), could prevent lung cancer growth and spread. Our results indicate that treatment of non-small cell lung cancer cells (A549 cells) with fursultiamine prevents A549 cells death in a dose-dependent manner. Similarly, live and dead cell staining assay also confirms that fursultiamine prevents proliferation of A549 cells. Further, fursultiamine prevents A549 cell proliferation by inducing the apoptotic cell death. It also promoted the activation of caspase-3 and cleavage of PARP protein. Fursultiamine also prevented reactive oxygen species in A549 cells. Further, fursultiamine regulated the expression of various anti-apoptotic (Bcl-2, Bcl-x) and pro-apoptotic (Cleaved Caspase-3), survival (Survivin) and anti-survival factors (Clusterin, p-Rad17) in A549 cells. We next planned to examine the effect of fursultiamine on lung cancer growth in vivo using athymic nude mice injected with A549 cells subcutaneously without or with a diet containing fursultiamine. In conclusion, our in vitro results suggest that vitamin B1 derivative, fursultiamine, by promoting the apoptotic pathways prevents lung cancer growth and has potential for further development as a chemoprevention drug.

Citation Format: Noah Boekweg, Ryan Powers, Kota Ramana. Vitamin B1 derivative, fursultiamine, prevents lung cancer cells growth [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 662.
Abstract 6646: Investigating the combination of radiation and subsequent immune checkpoint inhibitor treatment in head and neck squamous cell carcinoma models
Authors: Lind Hanne , Strait Alexander , Hall Spencer , Goon Jack B. , Aleman John D. , Chen Samantha , Owens Philip , Wang Jing H. , Young Christian , Wang Xiao-Jing
Published: March 2024

Purpose: Head and neck squamous cell carcinoma (HNSCC) is often marked by an immunosuppressive tumor microenvironment, which contributes to the dismal 10-20% response rate to immune checkpoint inhibitor (ICI) therapy in HNSCC patients. Radiotherapy (RT) is a currently standard of care and frontline therapy for HNSCC, yet resistance is common. We sought to examine the combination therapy of RT followed by ICI therapy to test if RT induces an in situ vaccination which enhances the efficacy of subsequent ICI.

Methods: We utilized SCC cell lines derived from K15.KrasG12D/Smad4−/− SCCs, which mimic the progression of HPV-unrelated HNSCC, and transplanted SCC cells into immune-competent C57BL/6J mouse recipients. Mice were subjected to RT followed by anti-PD-L1/anti-TGFb therapy. CD8+ splenic T cells of responder or non-responder mice were examined by paired single-cell VDJ sequencing and single cell RNA sequencing (TCR/sc-RNAseq) to look for adaptations of the cytotoxic T cell compartment following combination therapy. Responder and non-responder tumor lines or tumors were treated with RT alone in vitro and in vivo, respectively, to examine major histocompatibility complex I (MHC-I) levels on tumor cells.

Results: Responders to this combination therapy exhibited complete tumor eradication while non-responders displayed rapid tumor progression. When re-challenged with same HNSCCs cells, responders rejected implanted tumor cells while naïve recipients rapidly developed HNSCCs. Single-cell TCR sequencing of splenic CD8+ T cells revealed that responders, but not naïve recipients exhibited multiclonal CD8+ T cell expansion specifically of memory cell populations. Responder tumor cells exhibited greater levels of MHC-I protein level presentation than non-responders when stimulated with RT.

Conclusions: Our data suggest that 1) elevated MHC-I by SCC tumor cells presentation driven by RT and ICI combination therapy facilitate a systemic expansion of memory CD8+ T cell clonotypes which drive anti-tumor immunity and 2) MHC-I expression at baseline or when induced by RT may serve as a predictive marker for therapeutic response to RT and ICI combination therapy in HNSCCs.

Citation Format: Hanne Lind, Alexander Strait, Spencer Hall, Jack B. Goon, John D. Aleman, Samantha Chen, Philip Owens, Jing H. Wang, Christian Young, Xiao-Jing Wang. Investigating the combination of radiation and subsequent immune checkpoint inhibitor treatment in head and neck squamous cell carcinoma models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6646.
Abstract 6650: Macrophage pro-inflammatory phenotype skewing by the application of tumor treating fields (TTFields)
Authors: Kan Tal , Barsheshet Yiftah , Brant Boris , Khalil Tharwat Haj , Voloshin Tali , Volodin Alexandra , Koren Lilach , Koltun Bella , Klein-Goldberg Anat , Zemer-Tov Efrat , Paz Rom , Haber Adi , Giladi Moshe , Weinberg Uri , Palti Yoram
Published: March 2024

Introduction: Tumor Treating Fields (TTFields) are low intensity electric fields that disrupt cellular processes critical for cancer cell viability. TTFields have previously been shown to induce immunogenic cell death, promote dendritic cell maturation, and elicit a systemic anti-cancer immune response in preclinical models. The benefit of applying TTFields together with immune checkpoint inhibitors (ICI) was demonstrated in a phase 3 study in non-small cell lung carcinoma. In the current research, we investigated possible effects of TTFields on regulation of macrophage phenotype.

Methods: Bone marrow-derived macrophages (BMDMs) were generated from the femurs and tibias of 5-8-week-old Balb\C mice. LPS+IFN-γ or IL-4 were applied to the BMDMs to induce polarization (M1 and M2, respectively). The BMDMs were then treated with TTFields (150 kHz, 24 h), and then examined by flow cytometry for surface expression of the macrophage biomarker F4/80 and the activation markers CD80, major histocompatibility complex class II (MHC II), inducible nitric oxide synthase (iNOS), CD206, and ARG-1. Cell supernatants were collected and analyzed by multiplexed secretion assay for secretion levels of CXCL1 (KC), IL-18, IL-23, IL-12p70, IL6, TNF-α, IL-12p40, TGF-β1, CCL22 (MDC), IL-10, IL-6, G-CSF, CCL17 (TARC), and IL-1β. Cell lysates were examined using a RhoA activation kit and Western blot to determine GEF-H1, c-Jun, and p65 phosphorylation levels.

Results: BMDMs exposed to TTFields demonstrated elevated expression of the pro-inflammatory M1 markers CD80+ and MHC IIhigh, and decreased expression of the M2 markers CD206 and ARG-1. A pro-inflammatory secretion pattern was detected, with increased levels of CXCL1, IL-18, IL-23, IL-12p70, TNF-α, IL-12p40, CCL22, G-CSF, CCL17 and IL-1β. The treated cells further demonstrated RhoA activation and GEF-H1 phosphorylation, with subsequent activation of the transcription factors c-Jun and p65.

Conclusions: This study reveals a novel immunomodulatory role for TTFields, promoting in vitro pro-inflammatory polarization of macrophage.

Citation Format: Tal Kan, Yiftah Barsheshet, Boris Brant, Tharwat Haj Khalil, Tali Voloshin, Alexandra Volodin, Lilach Koren, Bella Koltun, Anat Klein-Goldberg, Efrat Zemer-Tov, Rom Paz, Adi Haber, Moshe Giladi, Uri Weinberg, Yoram Palti. Macrophage pro-inflammatory phenotype skewing by the application of tumor treating fields (TTFields) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6650.
Abstract 6674: Fungi utilizes exocytosis pathway to facilitate the release of DAMPs from pancreatic cancer cells
Authors: Alam Aftab , Mayengbam Shyamananda Singh , Senchanthisai Sharon , Irmak Bektas , Dey Prasenjit
Published: March 2024

Recent studies overwhelmingly show that microbiome is pervasive to tumor and play key role in immunotherapy response and reprograming tumor immune microenvironment (TIME). However, it remains unknown how microbiome facilitates the host-immune cell crosstalk and promote tumorigenesis. Our recent study in pancreatic ductal adenocarcinoma (PDAC) show that intratumor fungal microbiome facilitate the release of a damage associated molecular pattern (DAMP) molecule IL-33 from cancer cells. The secreted IL33 from cancer cells in turns recruits ILC2 and TH2 cells which promotes PDAC tumorigenesis. However, the mechanism of fungal mediated IL-33 release from PDAC cells remains unknown. Our follow up studies using high throughput integrated proteomic profiling and immunoprecipitation revealed a group of exocyst complex proteins interacting with IL-33 in the presence of fungus. The exocyst complex consists of eight sub-unit proteins that tethers the secretory vesicles to the plasma membrane and implicated in cellular exocytosis. We found EXOC6B a component of exocyst complex, modulates IL-33 release via exocytosis pathway from the PDAC cells. Genetic depletion of EXOC6B resulted in shunted IL-33 release and significantly abrogated PDAC tumor progression. Mechanistically, we found that mycobiome activates a non-canonical TLR2-CARD9 pathway, thereby driving IL-33 nucleocytoplasmic transport and exocytosis. This study identifies a unique mechanism of EXOC6B mediated release of IL-33 that expands our knowledge on how host-mycobiome interaction shapes PDAC tumor microenvironment by intricate molecular mechanism. Our study identifies EXOC6B as a new therapeutics target involved in the mycobiome driven IL-33 secretion in pancreatic cancer.

Citation Format: Aftab Alam, Shyamananda Singh Mayengbam, Sharon Senchanthisai, Bektas Irmak, Prasenjit Dey. Fungi utilizes exocytosis pathway to facilitate the release of DAMPs from pancreatic cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6674.
Abstract 672: Small molecule NSC59984 stimulates mitochondria-dependent ferroptosis and overcomes integrated stress response pro-survival signaling in pre-clinical pancreatic and colorectal cancer models
Authors: Srinivasan Praveen R. , De La Cruz Arielle J. , Pinho-Schwermann Maximilian , George Andrew , MacDonald William J. , Zhang Shengliang , El-Deiry Wafik S.
Published: March 2024

Pancreatic and colorectal cancer are leading causes of cancer deaths worldwide. Resistance to current therapeutics is a significant challenge in treating these cancers. Ferroptosis, a non-apoptotic iron-dependent form of cell death characterized by overwhelming lipid peroxidation, has emerged as a potential strategy to overcome drug resistance. Our lab previously identified the small-molecule NSC59984 as a p53 pathway restoring compound that induces reactive oxygen species, requires p73, and targets mutant p53 for ubiquitin-mediated proteolysis involving MDM2 and HSP90. In pre-clinical models of pancreatic and colorectal cancer, we now show that the small-molecule NSC59984 induces lipid peroxidation and causes reactive oxygen species-dependent apoptosis as monotherapy. However, when combined with ferroptosis inducers or cystine deprivation, NSC59984 potently induces ferroptosis in a mitochondrial complex III-dependent manner. Using CRISPR/Cas9 in pancreatic cancer cells, we further show that HRI, an EIF2-alpha kinase responsible for the cellular response to mitochondrial stress, induces the integrated stress response (ISR) upon treatment with NSC59984 or ferroptosis inducers. The ISR serves as a mechanism for resistance to cell death induced by NSC59984 or ferroptosis inducers, causing upregulation of key anti-oxidative stress and anti-ferroptosis proteins, including the cystine importer SLC7A11 and the GPX4-stabilizing protein HSPA5/BIP/GRP78. The combination therapy overcomes the ISR to induce potent cell death. Our work demonstrates the importance of the interplay between mitochondria and the ISR during ferroptosis induction in pancreatic and colorectal cancer cells.

Citation Format: Praveen R. Srinivasan, Arielle J. De La Cruz, Maximilian Pinho-Schwermann, Andrew George, William J. MacDonald, Shengliang Zhang, Wafik S. El-Deiry. Small molecule NSC59984 stimulates mitochondria-dependent ferroptosis and overcomes integrated stress response pro-survival signaling in pre-clinical pancreatic and colorectal cancer models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 672.
Abstract 673: Mechanisms of drugs in ovarian cancer and prevention of invasion and metastasis
Authors: Mortan Laura F. , Benbrook Doris
Published: March 2024

Introduction: Ovarian cancer patients are typically diagnosed late stage after the cancer has left the primary site, this is the major factor contributing to the 70% 5-year mortality rate. Standard of care is Platinum therapies or debulking surgery followed by maintenance therapies to keep cancer from coming back. The limitation to these therapies is overall toxicity to the patient forcing them to stop treatments or eventual resistance to the therapy. The objective of this study is to evaluate the mechanisms in which the novel drug, SHetA2, alone compares to the competitor, Olaparib. Additionally, discover the genetic differences between attached tumor and floating tumor in ascites.Objective: Our objective was to evaluate the mechanisms in which the novel drug, SHetA2, alone compares to the front-line competitor, Olaparib, in affecting Filamin A and cyclin d1 levels in ovarian cancer. Methods: Individual and combination drug treatments were preformed on two ovarian cancer cell lines and patient samples for cell viability assays. Immunocytochemistry was performed to visualize colocalization of proteins. RNA isolation was performed for Nanostring analysis.

Results: Ovarian cancer cells treated with SHetA2 or olaparib demonstrate a decrease of cyclin D1 on the membrane colocalized with filamin A, a structural protein that facilitates movement by acting as a signaling molecule for downstream effects. Nanostring analysis of attached tumor and spheroids form ascites shows significant differential gene expression in tumor versus ascites.

Conclusions: These results suggest the decrease of cyclin D1 with filamin A upon treatment with SHetA2 or olaparib could be one of the primary factors leading to each drug’s efficacy and additivity with each other. The differential gene expression of tumor versus ascites begins to elucidate the fundamental differences between attached and floating tumors and spheroids.

Citation Format: Laura F. Mortan, Doris Benbrook. Mechanisms of drugs in ovarian cancer and prevention of invasion and metastasis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 673.
Abstract 6768: Matched XPDX™derivative models as a platform for continuity across preclinical drug development
Authors: Millard Melissa , Carlson Aaron , Nadeau Danielle Y. , Burgess Kimberly J. , Simonson Alyssa , Diaz Armando , Wick Michael , DesRochers Teresa
Published: March 2024

Drug discovery is a reductive process in which druglike entities are carried through increasingly complex assay formats to tease out the compounds best suited for human studies. In vivo efficacy remains the benchmark for successful preclinical drug development. Cell-based models are a mainstay in early stages but translatability of different models across platforms remains a challenge. In oncology, patient-derived xenografts (PDX) are the gold standard for animal studies because they recapitulate key features of human tumors including the cellular heterogeneity, growth patterns, and drug response of the original patient tumor. Ex vivo, PDX derivatives have the potential to harness these same traits thereby extending the utility of PDX models to earlier stages of preclinical drug development. The KIYA-Predict™ platform is a clinically validated tool for the assessment of ex vivo drug responses across a broad range of drug classes that when applied to XPDX models shows good correlation to in vivo drug responses and excellent intra-sample reproducibility over time. Working with the well-characterized XenoSTART™ XPDX model repository, Kiyatec has derived 2D cell lines and organotypic 3D-expansion cultures to complement the ex vivo predictive value of our KIYA-PREDICT™ XPDX drug response profiling (DRP) platform. The development of syngeneic models applicable to simpler, high-throughput library screening (2D formats) and lower-throughput more complex mechanistic studies (3D organotypic models) could alleviate the burden and pitfalls of extrapolating data across unrelated models. Matched sets of 2D cell lines (2D-XPDX™) and 3D organotypic (XPDXO™) cultures were established from single cell suspensions of digested, mouse-cell depleted XPDX™ tissue samples. Drug response profiling of the XPDX™ in their various ex vivo culture formats showed relative similarities across platforms. Genomic profiling of the derivates confirmed shared tissue origin and retention of genomic and phenotypic signatures to varying degrees across models. Mechanistic evaluation of 3D organotypic culture demonstrated that disease-relevant biomarkers and processes are maintained. Together these results demonstrate the feasibility of this novel drug discovery platform that avoids ambiguity imparted by discordant models.

Citation Format: Melissa Millard, Aaron Carlson, Danielle Y. Nadeau, Kimberly J. Burgess, Alyssa Simonson, Armando Diaz, Michael Wick, Teresa DesRochers. Matched XPDX™derivative models as a platform for continuity across preclinical drug development [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6768.
Abstract 677: Discovery of a first-in-class allosteric inhibitor of the small GTPase Rac1
Authors: Silverman Robert , Cooper Alan , Kar Ronodip , Raman Mayuri V. , Ravirala Ramu , Shah Mubarak Hasan , Mahankali Sandeep , Goka Erik T.
Published: March 2024

The Rac1 signaling pathway is known to be hyperactivated in numerous solid tumors. We developed a Rac1 AlphaLISA assay that is amenable to high-throughput screening (HTS) to screen large libraries of small molecules. Based on molecular modeling of a putative allosteric binding site for several of the hits, we optimized a series of compounds that lead to RP-102124. RP-102124 engages with Rac1 in both biochemical and cellular target engagement assays. RP-102124 has greater potency than previously reported Rac1 inhibitors in biochemical assays, with potent inhibition of phenotypic characteristics of Rac signaling such as cell migration and cytoskeletal rearrangements. RP-102124 is a Racmulti inhibitor with activity against oncogenic Rac1b. RP-102124 is orally bioavailable and shows dose dependent inhibition of tumor growth in xenograft models at doses that are well-tolerated. RP-102124 is a first-in-class allosteric Racmulti inhibitor that shows promising therapeutic potential.

Citation Format: Robert Silverman, Alan Cooper, Ronodip Kar, Mayuri V. Raman, Ramu Ravirala, Mubarak Hasan Shah, Sandeep Mahankali, Erik T. Goka. Discovery of a first-in-class allosteric inhibitor of the small GTPase Rac1 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 677.
Abstract 6779: Modality agnostic tumor models of cancer which can more accurately define drug efficacy and mechanism to help develop more effective therapeutics
Authors: Samuel Preethi , Ochola Damieanus Odour , Del Mundo Huckie , Dave Bhuvanesh
Published: March 2024

Introduction: In the path to clinic, researchers require robust tools to effectively evaluate the capacity of novel therapeutic modalities to generate anti-tumor responses. Using human-relevant, translational ex-vivo models is widely considered to reduce attrition during drug discovery and development for a more effective prediction of clinical outcomes during preclinical testing of drug candidates. Methods: The three levels of our patient derived tumoroid model platform, COMPASS (Custom Organoid Modeling Platform for Accurate SolutionS) was built to be versatile modality-agnostic human on human model system for pre-clinical testing. COMPASS 1 has stroma with epithelium; COMPASS 2 has stroma, epithelium, and immune components (from PBMCs) and COMPASS 3 has stroma, epithelium, immune components, and oxygenation. For widespread adaptation and utilization of our COMPASS platform we encourage extensive characterization by articulating the context of use to help build confidence in cases where limited knowledge and only few real-life cases exist. Results: Our proof-of-concept examples articulating the context of use demonstrate the modality-agnostic adaptability our COMPASS platform brings to the field of preclinical testing. We encourage a collaborative approach with researchers to support their testing needs to build confidence in our model to enable transition from existing screens, assays, and animal models. We envision preclinical use of COMPASS to help stratify patients for clinical trials, identify subpopulations that need dose modification and predict the response of patients and/or their risk of adverse effects. Conclusion: Due to its greater physiological relevance and ability to encompass downstream processes in a time and cost-efficient way, industry and academia should deliberate the impact platform such as COMPASS would have on their workflow and consider adapting to using these models routinely.

Citation Format: Preethi Samuel, Damieanus Odour Ochola, Huckie Del Mundo, Bhuvanesh Dave. Modality agnostic tumor models of cancer which can more accurately define drug efficacy and mechanism to help develop more effective therapeutics [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6779.
Abstract 6785: KIYA-PREDICT™ XPDX: An ex vivo 3D spheroid platform for modeling in vivo responses to multiple classes of oncology therapeutics
Authors: Carlson Aaron L. , Dance Natalie W. , Burgess Kimberly J. , Nadeau Danielle Y. , Millard Melissa , Simonson Alyssa , Diaz Armando , Wick Michael , DesRochers Teresa M.
Published: March 2024

Patient-derived xenografts (PDX) are a powerful and commonly used tool in preclinical drug development as they represent an in vivo platform for screening drug response in human tumors that recapitulate many molecular and histological features of the original patient tumor. However, these models are costly and time-intensive, necessitating the development of ex vivo platforms for assessing drug response to PDX-derived tumors to de-risk in vivo studies by aiding in model selection and reducing the number of animals and costs associated with in vivo experimentation. The KIYA-PREDICT™ platform is a clinically validated, ex vivo 3D cell culture platform with demonstrated ability to predict patient response to chemotherapy in high grade glioma and ovarian cancer. Here, we apply this platform to profiling XPDX from XenoSTART’s comprehensive library of well-characterized models as a tool for assessing drug response and mechanism of action ex vivo while also aiding in model selection for in vivo studies. Over 100 XPDX models have been profiled ex vivo for response to several classes of cancer therapeutics, including chemotherapy, targeted therapy, and antibody-drug conjugates (ADCs), demonstrating robust concordance with in vivo drug response. CDK4/6 inhibitors palbociclib and ribociclib evaluated ex vivo in breast XPDX display strong correlation to in vivo response and recapitulate palbociclib resistance. Similarly, G12C inhibitors sotorasib (AMG-510) and adagrasib (MRTX849) screened against a panel of non-small cell lung cancer XPDX ex vivo match in vivo response and drug resistance. Finally, ex vivo and in vivo responses to FDA approved ADC enfortumab vedotin were evaluated in a panel of bladder cancer PDX, with ex vivo and in vivo responses showing good concordance and expected modulation based on Nectin-4 expression levels. The combination of the KIYA-PREDICT™ platform with XenoSTART’s XPDX catalogue is a flexible and powerful tool that can be utilized for streamlining preclinical drug development for a wide range of therapeutic classes.

Citation Format: Aaron L. Carlson, Natalie W. Dance, Kimberly J. Burgess, Danielle Y. Nadeau, Melissa Millard, Alyssa Simonson, Armando Diaz, Michael Wick, Teresa M. DesRochers. KIYA-PREDICT™ XPDX: An ex vivo 3D spheroid platform for modeling in vivo responses to multiple classes of oncology therapeutics [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6785.