bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 3645: Unraveling spatial complexity of the tumor microenvironment: A whole transcriptomic perspective with Visium HD
Authors: Yin Yifeng , Sapida Jerald , Sukovich David , Patterson David , Tentori Augusto
Published: March 2024

In recent years, advances in spatial transcriptomics have revolutionized our understanding of the tumor microenvironment, providing crucial insights into the complex interplay of different cell types within cancer tissues. In this study, we employed the new, high definition Visium spatial transcriptomics assay (Visium HD) to investigate the intricate molecular landscape of prostate cancer at single-cell scale resolution and across the whole transcriptome. Our research focused on deciphering the spatial heterogeneity of gene expression patterns within the tumor microenvironment, shedding light on the interactions between cancer cells, stromal cells, and vasculature.

The Visium HD assay enables an unbiased exploration of the transcriptome on FFPE tissue sections mounted on standard glass slides. Combining gene expression data with H&E images from the same section, it allows precise characterization of local molecular features and disease states at single-cell scale. We analyzed a set of human prostate adenocarcinoma samples with the Visium HD assay, and identified spatially regulated gene signatures associated with specific cell types and functional pathways. Our findings have recapitulated previously identified molecular markers, including VEGFA and MYC which have been implicated in tumor progression and angiogenesis. The spatial gene expression patterns had good correlation with histological annotations of cancerous and normal tissue within the H&E image. However, Visium HD allowed us to further observe molecular processes and pathways specific to this adenocarcinoma sample. This integrative approach offers valuable implications for personalized cancer therapy and the development of targeted interventions tailored to the spatial context of individual tumors.

Our study underscores the significance of understanding the spatial organization of the whole transcriptome in cancer tissues, and highlights the potential of the Visium HD platform as a powerful tool for unraveling the complexities of the tumor microenvironment. These insights pave the way for the development of innovative therapeutic strategies and precision medicine approaches, ultimately contributing to improved outcomes for cancer patients.

Citation Format: Yifeng Yin, Jerald Sapida, David Sukovich, David Patterson, Augusto Tentori. Unraveling spatial complexity of the tumor microenvironment: A whole transcriptomic perspective with Visium HD [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 3645.
Abstract 3719: Fasting-mimicking diet plus 2-DG drives antitumor immunity by targeting EDEM3-induced PD-L1 glycosylation
Authors: Liu Xiaoxia , Peng Shaoyong , Wang Xiaolin , Yu Huichuan , Luo Yanxin
Published: March 2024

The PD-1/PD-L1 axis plays an essential role in immune escape and immunotherapy. Importantly, translated N-linked glycosylation of PD-L1 stabilizes protein, enters the cell membrane binding to PD-1, renders T cells anergic and leads to T-cell exhaustion and dysfunction. Targeting PD-L1 glycosylation as an attractive target by a rational combination of cancer immunotherapies. Cancer-associated fibroblasts (CAFs), a predominant cell component of the tumor microenvironment, exert crucial functions in promoting immune escape and immunotherapy resistance by increasing the tumor PD-L1 expression. However, whether and how CAFs upregulate the glycosylation of PD-L1 has never been reported. This study shows that CAFs can upregulate PD-L1 glycosylation and enhance PD-L1 cell surface expression via glycosyltransferase EDEM3, thus cancer immune evasion. Then, the study delves into the relationship between EDEM3 expression, prognosis and immunogenicity. We demonstrate that EDEM3 plays a role in tumor immunity during tumor progression, as evidenced by EDEM3 expression is only significantly correlated with poor prognosis in the CD8+ T cell-enriched population. In subcutaneous tumor models, we observed high cell-surface PD-L1 expression accompanied by decreased CD8+ T cell infiltration and increased M2 macrophage in immunocompetent mice transplanted with EDEM3 over-expressed CRC cells that promote resistance to PD-1/PD-L1 blockade cancer immunotherapy. By performing bioinformatic analysis, we found that the hexosamine biosynthesis pathway (HBP) is highly affected in EDEM3-upregulated CRC cancer. Subsequently, the production of the UDP-GlcNAc (the end product of HBP metabolic flow), a donor substrate for N-linked glycosylation, is significantly increased in EDEM3 over-expressed CRC cells by LC/MS. Meanwhile, glucose is confirmed to be the primary effector of PD-L1 glycosylation in CRC cells, and the glucose restriction attenuates EDEM3-modified PD-L1 glycosylation by reducing UDP-GlcNAc biosynthesis. Finally, we demonstrate that modulation of glucose metabolism through a fasting-mimicking diet (FMD) in combination with 2-deoxy glucose (2-DG) treatment enhances antitumor immunity, especially in tumors with high-EDEM3 expression that exhibit resistance to immunotherapy. We propose potential therapeutic targets for CRC that inhibit PD-L1 glycosylation through FMD+2-DG and could augment the efficacy of immune checkpoint blockers.

Citation Format: Xiaoxia Liu, Shaoyong Peng, Xiaolin Wang, Huichuan Yu, Yanxin Luo. Fasting-mimicking diet plus 2-DG drives antitumor immunity by targeting EDEM3-induced PD-L1 glycosylation [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 3719.
Abstract 3731: Spliceosome: A gatekeeper for necroptosis
Authors: Jiang Xinpei , Ma Xueying , Balachandran Siddharth , Cañadas Israel
Published: March 2024

Small cell lung cancer (SCLC) is the most aggressive type of lung cancer with a 5-year overall survival of approximately 5%. SCLC has high prevalence of somatic mutations, yet express low to zero neoantigen. Despite promising advances in immunotherapy, highly metastatic SCLC remains a devastating disease and only a small fraction of SCLC patients respond to immunotherapy. These poor survival and lack of therapy options stresses the unmet need to identify novel and effective targeted therapies for metastatic SCLC. Here, we demonstrate that targeting the splicing core component, SF3B1, in SCLC, is a molecular trigger for tumor killing and viral mimicry.SF3B1 inhibition through the small molecule Pladienolide B (PlaB) induces the accumulation of immunogenic double-stranded RNAs (dsRNAs), including right-handed dsRNA conformation (A-RNA), provoking a tumor-intrinsic innate immune response and tumor cell death in SCLC preclinical models. Strikingly, we discovered that PlaB treatment also induces the formation of Z-form nucleic acids (Z-NAs), which are unique, left-handed nucleic acids and necroptosis-activating ligands for the host sensor ZBP1.These endogenous A-RNAs and Z-NAs initiate tumor-intrinsic antiviral interferon (IFN) signaling in SCLC cells leading to tumor-intrinsic immunogenicity and apoptosis. Notably, we also found that Z-NAs derived from spliceosome inhibition trigger the activation of ZBP1, inducing RIPK3-mediated MLKL activation and eventual necroptosis, a highly immunogenic cell-death pathway, in ‘necroptosis competent’ cells, including mouse embryonic fibroblasts (MEFs). This opens unexplored strategies for spliceosome inhibitors to activate anti-tumor immune pathways not only in tumor cells themselves, but also in cells of the Tumor Microenvironment (TME), which too can break tolerance and enhance anti-tumor T cell responses which is crucial to enhance cancer immunotherapy responses. These findings demonstrate a unique and novel spliceosome-targeted mechanism to remodel the immunosuppressive TME of SCLCs. Also, our study suggests that SF3B1 inhibitors and potentially other spliceosome inhibitors might be used not only to selectively kill tumor cells, but also as compounds to generate Z-NAs in tumor cells and cells of the TME and trigger on-demand necroptosis without need for an active virus infection.

Citation Format: Xinpei Jiang, Xueying Ma, Siddharth Balachandran, Israel Cañadas. Spliceosome: A gatekeeper for necroptosis [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 3731.
Abstract 3788: EpCAM+ DCCs isolated from the bone marrow of breast cancer patients display high stemness and potency scores
Authors: Raya Elia , Koerkel-Qu Huiqin , Rudhart Laura , Köhler Lisa-Marie , Damboeck Anna , Irlbeck Christoph , Botteron Catherine , Werner-Klein Melanie , Seitz Stephan , Klein Christoph
Published: March 2024

Metastatic dissemination of cancer cells from primary to distant sites often occurs early and it has been shown that their detection is linked to poor outcomes. Eradication of disseminated cancer cells (DCC) has therefore become the primary goal of adjuvant therapies. Since the phenotype of DCC is largely unknown, we set out to search, isolate, and molecularly characterize these candidate metastasis founder cells from bone marrow of breast cancer patients, years before manifestation of metastasis.

We screened more than 200 bone marrow samples of breast cancer patients with no evident metastasis (UICC stage M0) for EpCAM-positive cells. EpCAM positive cells in the bone marrow of healthy donors were used as a negative control. In addition, we isolated DCC from breast cancer patients with manifest metastasis (UICC stage M1). We then performed single cell RNA sequencing after whole transcriptome amplification of the collected DCC and the healthy donor (HD) control cells. To confirm the malignant origin of picked DCCs, we projected the transcriptome data into the bone marrow atlas, inferred copy number alterations, and searched for mutations shared with the matched primary tumor. EpCAM-positive cells from control patients mostly comprised plasma cells. In contrast, DCCs derived from M0-stage breast cancer patient formed a unique, non-overlapping cluster in the bone marrow atlas. UMAP-clustering placed M1-stage DCC clearly separate from M0 stage DCC. Among the collected M0-stage DCCs, we identified at least three separate subclusters. Strikingly, M0-stage DCC displayed much higher stemness and potency scores than M1-stage DCCs, reminiscent of embryonic cells. DCCs, identified by EpCAM, display very high transcriptional stemness scores when isolated before metastatic manifestation. Upon expansion and proliferation, stemness scores are reduced indicating epithelial re-differentiation. The embryonic phenotype of M0-stage DCCs may reflect an early adaptive mechanism that enables DCC to survive in an ectopic environment and may impact on the metastatic potential of the DCC.

Citation Format: Elia Raya, Huiqin Koerkel-Qu, Laura Rudhart, Lisa-Marie Köhler, Anna Damboeck, Christoph Irlbeck, Catherine Botteron, Melanie Werner-Klein, Stephan Seitz, Christoph Klein. EpCAM+ DCCs isolated from the bone marrow of breast cancer patients display high stemness and potency scores [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 3788.
Abstract 3801: Spatially resolved laser-activated cell sorting (SLACS) for high throughput spatial cell sorting in tumor research
Authors: Lee Sumin , Lee Amos Chungwon
Published: March 2024

Understanding of tumor heterogeneity and the microenvironment is a cornerstone in advancing cancer research and therapy. The Spatially resolved Laser-Activated Cell Sorter (SLACS) represents a novel approach in cancer research, allowing for high-throughput, precise cell isolation while preserving spatial information, which is crucial for studying tumor heterogeneity and the tumor microenvironment. The SLACS instrument utilizes laser-activated technology for selective isolation of cells from heterogeneous tissue samples, optimized for accuracy, speed, and minimal cell damage. This instrument has demonstrated effective isolation of specific cell types from complex tissue matrices, maintaining cell integrity and spatial information. Its high-throughput capacity significantly reduces sample processing time. This groundbreaking tool offers detailed exploration of tumor heterogeneity and the tumor microenvironment, providing valuable insights into cancer biology and potential therapeutic targets.

Citation Format: Sumin Lee, Amos Chungwon Lee. Spatially resolved laser-activated cell sorting (SLACS) for high throughput spatial cell sorting in tumor research [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 3801.
Abstract 3881: Discovery of highly potent, selective and efficacious STAT3 PROTAC degraders capable of achieving long-lasting tumor regression
Authors: Zhou Haibin , Wu Dimin , Bai Longchuan , Acharyya Ranjan K. , Metwally Hoda , McEachern Donna , Wen Bo , Sun Duxin , Wang Shaomeng
Published: March 2024

STAT3 (signal transducer and activator of transcription 3) is a transcription factor and a promising therapeutic targets for cancer and other human diseases. We have previously reported the discovery of SD-36 and SD-91 as potent, selective and highly efficacious STAT3 degraders. In the present study, we report the discovery and extensive evaluation of new, highly potent, selective and efficacious new STAT3 degraders. In direct comparison, these compounds are >50-times more potent than SD-36 in inducing STAT3 degradation in cells and demonstrates >500-fold degradation selectivity over other STAT members. Proteomic analysis showed that our best lead compound (UM-STAT3-1218) only reduces the levels of STAT3 protein in cells over other >6,700 proteins. (UM-STAT3-1218) achieves low nanomolar IC50 values in leukemia and lymphoma cancer cell lines with activated STAT3. A single intravenous dose of (UM-STAT3-1218) at 3 mg/kg reduces the STAT3 protein for >4 days in xenograft tumor and native tissues, without reducing another other STAT members. Impressively, a single dose of (UM-STAT3-1218) at 3 mg/kg achieves complete and long-lasting tumor regression in multiple xenograft tumor models without any signs of toxicity. Taken together, (UM-STAT3-1218) is a highly promising STAT3 degrader for the treatment of the treatment of human cancers and other human diseases in which STAT3 plays a key role.

Citation Format: Haibin Zhou, Dimin Wu, Longchuan Bai, Ranjan K. Acharyya, Hoda Metwally, Donna McEachern, Bo Wen, Duxin Sun, Shaomeng Wang. Discovery of highly potent, selective and efficacious STAT3 PROTAC degraders capable of achieving long-lasting tumor regression [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 3881.
Abstract 3906: Ex vivo breast tumors for understanding the patient specific tumor microenvironment remodeling and drug responses
Authors: Martin Elizabeth , Benz Megan , Hebert Katie , Byrne Ethan , Lau Frank
Published: March 2024

Breast cancer is a heterogeneous disease driven by cell-intrinsic and cell-extrinsic signaling cues. Many of these cues derive from the tumor microenvironment (TME), which is composed of adipocytes, vasculature, stem cells, immune cells, and the extracellular matrix (ECM). Through these diverse components, the TME modulates cellular proliferation, survival, and ultimately response to therapy. Despite this high-level understanding of tumor-TME crosstalk, no existing pre-clinical models accurately capture the TME in vitro. We overcame that hurdle by developing a method to maintain healthy human breast tissue (HBT) alive ex vivo for at least 8 weeks. By culturing breast cancer cells in that HBT, we created ex vivo breast tumors (EVBTs) that retained patient-specific features relevant to breast cancer including menopause status, obesity status, and response to therapy. Using these EVBTs, we demonstrate breast cancer subtype-specific alterations in lipid accumulation, ECM remodeling, and cytokine profiles. RNA sequencing showed that breast cancer cell line signatures were retained in the EVBTs system at 1 week and 2 weeks in vitro. We demonstrated donor-specific transcriptional changes to the core matrisome gene set. Finally, we demonstrate that our EVBTs retained patient-specific heterogeneity in response to standard of care endocrine therapy and neoadjuvant chemotherapies. Our novel tumor model allows for 1) real-time examination of breast cancer interactions with HBT and the TME and 2) the isolation of breast cancer-specific factors vs. patient-specific factors in the development and progression of breast cancer.

Citation Format: Elizabeth Martin, Megan Benz, Katie Hebert, Ethan Byrne, Frank Lau. Ex vivo breast tumors for understanding the patient specific tumor microenvironment remodeling and drug responses [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 3906.
Abstract 3973: Cancer B cell blueprint reveals dysfunctional extra-follicular dominance with therapeutic opportunity
Authors: Ma Jiaqiang , Wu Yingcheng , Ma Lifeng , Yang Xupeng , Zhang Tiancheng , Guo Guoji , Fan Jia , Zhang Xiaoming , Gao Qiang
Published: March 2024

B cells are essential components of humoral immunity but harbor multifaceted functions across cancers. To decode tumor-infiltrating B cells, we generated the B cell blueprint encompassing single-cell transcriptome, BCR repertoire, and chromatin accessibility data across 20 cancer types (483 samples, 266 patients). Strikingly, B cells harbored extraordinary heterogeneity and composed of 15 subsets, which were grouped into two independent developmental paths (extra-follicular [EF] versus germinal-center [GC]) exhibiting organ preference. Of note, colon adenocarcinoma and hepatocellular carcinoma are the two representative types of cancer enriched for GC and EF pathways, respectively. We affirm that EF-dominant cancers correlate with dysregulated immune responses and worse clinical outcomes. We then identify the dynamic metabolic-epigenetic-signaling networks in fine-tuning tumor-infiltrating B cell differentiation and managing the balance between the EF and GC pathways. Atypical memory (AtM) B cells, the primary progenitors of EF-derived ASCs, exhibit an exhausted and bystander phenotype and develop independently of the GC pathway. We find that the AtM B cells reside in the center of immature TLSs and spatially relocate to the periphery during TLS maturation. Finally, we mechanistically link these findings to specific transcription factors and epigenomic regulations. We demonstrate that the glutamine-derived metabolite α-ketoglutarate (αKG) could increase the expression of AtM B cell associated transcription factors Tbet and BATF and promote their differentiation, accompanied by the activation of mammalian target of rapamycin complex 1 (mTORC1) signaling. Consequently, AtM B cells acquire an immunoregulatory function that dampens anti-tumor T cell responses and fosters an immunosuppressive microenvironment.

Citation Format: Jiaqiang Ma, Yingcheng Wu, Lifeng Ma, Xupeng Yang, Tiancheng Zhang, Guoji Guo, Jia Fan, Xiaoming Zhang, Qiang Gao. Cancer B cell blueprint reveals dysfunctional extra-follicular dominance with therapeutic opportunity [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 3973.
Abstract 3982: Evaluating the effects of obesity on immune responses in renal tumors
Authors: Dempsey Francesca , Norian Lyse
Published: March 2024

Understanding the effects of obesity on cancer progression and treatment is a critically important area of research. Obesity is reaching epidemic proportions in our country and is known to increase the risk for many cancers, including renal cell carcinoma, which is among the ten most common cancers in both men and women. Our lab has shown that obesity leads to worse outcomes in advanced renal cancer patients treated with immunotherapy as compared to lean patients, but the cause for this difference is unknown. To investigate this further, we utilized a murine model with diet-induced obese mice and lean mice that were challenged with orthotopic renal tumors. The tumors grew out over three weeks and were harvested for flow cytometry staining. We stained for markers associated with immune function to better characterize what might be causing patients with obesity to be less responsive to immunotherapy. Our preliminary findings show that DIO mice had a greater tumor burden than lean controls over time. We also found that there compositional differences in multiple subsets of T cells in DIO versus lean mice. In the future, we will expand our murine studies to evaluate the phenotype and function of both tumor cells and immune cells. Additionally, we will continue these studies in human samples to further examine associations between obesity and immunotherapy outcomes.

Citation Format: Francesca Dempsey, Lyse Norian. Evaluating the effects of obesity on immune responses in renal 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 3982.
Abstract 4032: ATRA induces an interferon response to reprogram the immunosuppressive tumor microenvironment and overcomes resistance to immune checkpoint inhibition in murine models of LKB1-deficient non-small cell lung cancer
Authors: Crosson William P. , Li Rui , Salehi-Rad Ramin , Lim Raymond J. , Abascal Jensen , Kahangi Bitta P. , Reyes Edgar Perez , Oh Michael , Dumitras Camelia , Edgar Nico , Chew Ryan , Jocobo Rashel , Tfayli Adam , Jing Zhe , Krysan Kostyantyn , Tran Linh , Dubinett Steven M. , Liu Bin
Published: March 2024

Lung cancer remains the deadliest form of cancer, claiming 1.8 million lives worldwide in 2020. While treatment options have improved with the advent of immune checkpoint inhibitors (ICI), many patients do not respond to immunotherapy or develop resistance following initial response. A significant subset of non-small cell lung cancer (NSCLC) patients harbors somatic co-mutations in Kirsten rat sarcoma virus (KRAS) and Liver kinase 1 [LKB1, also known as serine/threonine kinase 11 (STK11)] genes, whose tumors are characterized by an immunosuppressive tumor microenvironment (TME) that are resistant to ICI. Our studies revealed that all-trans retinoic acid (ATRA), a metabolite derived from vitamin A, sensitized a murine model of NSCLC with increased tumor mutational burden (Kras G12D P53-/-Lkb1-/-; KPL-3M) to PD-1 blockade. The ATRA and anti-PD-1 combination therapy improved local and systemic T cell activation and generated systemic tumor-specific immunity. To understand ATRA-mediated anti-tumor effects, we performed single cell RNA sequencing (scRNA-seq) of KPL-3M murine tumors with or without 6 daily ATRA treatments. scRNA-seq analysis revealed a reduction of neutrophils as well as an enrichment in T cell and natural killer (NK) cell populations in the TME. Furthermore, scRNA-seq analysis revealed elevated expression of interferon (IFN) downstream genes in multiple immune subpopulations in the TME. Preliminary ex vivo studies indicated that ATRA increases NOX2 levels, intracellular reactive oxygen species (ROS), and IFN signaling in the neutrophils in KPL-3M tumors. Our findings suggest that ATRA may reshape the TME by activating IFN signaling in multiple cell subtypes to sensitize resistant tumors to ICI immunotherapy.

Citation Format: William P. Crosson, Rui Li, Ramin Salehi-Rad, Raymond J. Lim, Jensen Abascal, Bitta P. Kahangi, Edgar Perez Reyes, Michael Oh, Camelia Dumitras, Nico Edgar, Ryan Chew, Rashel Jocobo, Adam Tfayli, Zhe Jing, Kostyantyn Krysan, Linh Tran, Steven M. Dubinett, Bin Liu. ATRA induces an interferon response to reprogram the immunosuppressive tumor microenvironment and overcomes resistance to immune checkpoint inhibition in murine models of LKB1-deficient non-small cell lung 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 4032.
Abstract 4044: Potentiated antitumor activity of poly-γ-glutamic acid combined with anti PD-L1 blockade on murine models of colorectal cancer
Authors: Jang Jae-Pyung , Yoo Chan-Hee , Hahm Kyung-Soo , Lee Do Young , Park Young-Chul , Choi Jae Chul
Published: March 2024

Objective: Immune checkpoint inhibitors(ICIs) have been shown to be key role in cancer therapy. Especially, antibodies targeting programmed cell death ligand1(PD-L1) promoted T cells to activate immune response against cancer cells. However, the current ICIs still have insignificant to motivate effective antitumor immunity by blocking PD-1/PD-L1 pathway and the regulatory network of PD-L1 by cytokines in the tumor microenvironment remains to be uncovered. Previously, we have reported the anti-cancer effects of combination treatment with a natural product, poly-γ-glutamic acid(γ-PGA), and PD-1 blockade. Now, we show that combination therapy with anti PD-L1 and γ-PGA can overcome the limits of ICIs and enhance anticancer effect in murine colorectal cancer.

Design: In vivo efficacy studies were performed by intraperitoneal injection of antibody targeting PD-L1 and oral administration of γ-PGA in C57BL/6 model transplanted with mouse tumor cell lines. Systemic changes in immunophenotype was measured by tumor volume size and body weight. The splenocyte was isolated from mice and the populations of myeloid-driven suppressor cells(MDSCs) and CD4/CD8 T cells were analyzed by FACS. Also, the significant cytokines activated by T- cell, IFN-γ and IL-2, were measured by ELISA.

Results and Conclusions: In murine model of colorectal cancer, γ-PGA and anti PD-L1 blockade combination therapy significantly improved anti-tumor activity compared with single agents. In addition, tumoral infiltration of CD8+ T cells and IFN-γ productions were increased by γ-PGA, and its antitumoral activity was attenuated by antibody-mediated depletion of these cells, indicating that g-PGA suppressed tumor growth in a CD8 T cell-dependent manner. Therefore, our results suggest that γ-PGA promote ICI-mediated antitumor responses by the transformation of "cold tumors" into “hot tumors”

Citation Format: Jae-Pyung Jang, Chan-Hee Yoo, Kyung-Soo Hahm, Do Young Lee, Young-Chul Park, Jae Chul Choi. Potentiated antitumor activity of poly-γ-glutamic acid combined with anti PD-L1 blockade on murine models of colorectal 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 4044.
Abstract 408: NEK1 phosphorylation modulates ERCC6 in transcription coupled nucleotide excision repair with implications for prostate cancer
Authors: Ogundepo Oluwatobi M. , De Benedetti Arrigo
Published: March 2024

NER operates through two distinct pathways: global genome repair (GGR) and transcription-coupled repair (TC-NER). TC-NER, as its name suggests, is specifically dedicated to rectifying lesions that obstruct the progression of RNA polymerase during active transcription. This process is imperative for the maintenance of cellular homeostasis, as lesions encountered by the transcription machinery can lead to stalling, erroneous transcription, and ultimately, deleterious cellular outcomes. At the heart of the TC-NER pathway lies ERCC6, a helicase orchestrating the repair of DNA lesions within transcribed regions of the genome. ERCC6 (AKA CS-B) plays a pivotal role in detecting and coordinating the repair of transcription-blocking lesions and has been implicated in a plethora of cellular processes underscoring its multifaceted nature and its broader impact on genome stability and cellular health, as exemplified by the severity of syndromes in individuals with loss-of-function mutations. In the US, compared to Caucasians (CC), AA are at higher risk for developing PCa and have more aggressive disease that is refractory to treatment, to some extent explained by genetic differences in some cases attributed to alterations of their “Repairome”. GWAS revealed that, unlike CC, 89% of AA-PCa have at least one mutation in NER pathway genes. A defect in ERCC6 activity, either through reduced expression or mutation (e.g., M1097V found frequently in AA) may result in impaired TC-NER. This may be compounded by aging or obesity-related oxidative stress, resulting in progressive accumulation of damaged bases (e.g., 8-OG) and consequent (cancer-propensity) mutations, the correction of which involves BER or NER. This was investigated in part with PCa cell lines engineered via CRISPR-SDM to carry that particular genomic mutation, by studying their sensitivity to UV and the efficiency of removal of CPDs in vivo. In addition, we have begun investigation of its function in the variants (engineered and naturally found in PCa. Lines) in vitro, after IP from cells, by studying its intrinsic ATPase activity. We have also identified the kinase NEK1 as an important novel interactor and regulator of ERCC6. We previously identified NEK1 as being an early regulator of the adaptive response of PCa cells to ADT.

Citation Format: Oluwatobi M. Ogundepo, Arrigo De Benedetti. NEK1 phosphorylation modulates ERCC6 in transcription coupled nucleotide excision repair with implications for prostate 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 408.
Abstract 4092: Characterizing the endogenous retroviral envelope protein ERVMER34-1 as a target for a therapeutic cancer vaccine
Authors: Maldonado Maria Del Mar , Iida Masafumi , Hernandez Maria Del Mar Gracia , Le Loc , Donahue Renee N. , Palena Claudia , Schlom Jeffrey , Hamilton Duane H.
Published: March 2024

Endogenous retroviruses (ERVs) are remnants of retroviral germline infections which occurred over the course of evolution and constitute between 5-8% of the human genome. Although ERV protein expression is typically silenced epigenetically in normal adult human tissues, previous studies have shown that some ERVSs, can be aberrantly expressed in multiple cancer types. This atypical expression of ERVs in tumors may represent a class of immunologically relevant tumor-associated antigens that can potentially be targeted clinically using therapeutic cancer vaccines. For the first time, this study evaluates the ERV envelope protein ERVMER34-1 as a potential target for a therapeutic cancer vaccine. We first assessed the expression of ERVMER34-1 in multiple tissues and found that ERVMER34-1 protein is absent in most healthy adult tissues and over expressed in multiple types of human carcinomas. ERVMER34-1 specific T-cells were detected in PBMCs of cancer patients but not healthy donors following an overnight stimulation. However, reactive T-cells are readily expanded from both healthy donor and cancer patient PBMCs following a 7-day in-vitro stimulation. Importantly, reactive CD8+ T cells selectively killed human carcinoma cells expressing the target antigen. Based on these findings, we rationally designed a ERVMER34-1 therapeutic cancer vaccine and assessed its immunogenicity and anti-tumor efficacy in established syngeneic murine tumors expressing the full-length ERVMER34-1 protein. Our rationally designed ERVMER34-1 cancer vaccine significantly mediated tumor regression and extended survival as a monotherapy and in combination with checkpoint blockade. Altogether, our work supports the clinical development of a therapeutic cancer vaccine targeting the retroviral envelope protein ERVMER34-1 as a potential first-in-class immunotherapeutic target for the therapy of several carcinoma types.

Citation Format: Maria Del Mar Maldonado, Masafumi Iida, Maria Del Mar Gracia Hernandez, Loc Le, Renee N. Donahue, Claudia Palena, Jeffrey Schlom, Duane H. Hamilton. Characterizing the endogenous retroviral envelope protein ERVMER34-1 as a target for a therapeutic cancer vaccine [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 4092.
Abstract 4177: High-throughput in vivo monitoring of splenomegaly and tumor burden in a murine breast cancer model
Authors: McMannus Craig , Czernuszewicz Tomek J. , Gessner Ryan C. , Peterson Jeffrey D.
Published: March 2024

Splenomegaly is a valuable parameter in mouse model cancer studies, as it can reflect the magnitude of cancer burden, hematopoietic activity, immune status, and can provide an indirect measure of cancer treatment efficacy. In liquid cancer models specifically (leukemia/lymphoma), spleen sizing is important as it is usually the only measure of in vivo tumor burden that can be assessed noninvasively without genetic labeling of tumor cells. Magnetic resonance imaging (MRI) and contrast-enhanced computed tomography (CT) are highly effective at evaluating spleen size in small animals. However, these techniques can impose limitations on large-cohort study designs due to high cost, long scan time, and ionizing radiation. Ultrasound is an alternative method with lower cost, high frame rate, and no ionization, but can suffer from poor inter-user variability, limited 2D field-of-view, and low throughput due to manual operation. In this work, we evaluated a novel 3D automated ultrasound scanner (Vega, Revvity, Inc.) for rapid assessment of splenomegaly in a murine cancer model. Female BALB/c mice (n=10) were implanted with 5e5 4T1 (ATCC) cells on the right flank. Mice were imaged at five timepoints over 25 days to track longitudinal progression of both spleen and tumor enlargement. Images were segmented manually in 3D using the “Slice Draw” and “Fill Between Slices” effects in SonoEQ v2.0.1 (Revvity, Inc.) to quantify tissue volume. After the final timepoint, mice were euthanized, and spleen weight was measured ex vivo. An additional cohort of age-matched mice without tumors (n=7) were imaged at the final timepoint to serve as controls. Imaging revealed a substantial enlargement of the spleen over time, from 30 ± 3 mm3 to 545 ± 105 mm3, representing an 18-fold increase. In the same time span, tumor volume grew to 1966 ± 87 mm3. Correlation analysis demonstrated good agreement between ultrasound volumes and ex vivo spleen weights (R² = 0.90). The results in this study demonstrate that noninvasive, nonlabelled quantification of murine spleen size with automated ultrasound is feasible, robust, and fast. The average time to acquire the spleen image for each mouse was less than 30 seconds. Future studies will apply this workflow in liquid cancer models, as well as explore using machine learning approaches to automatically segment spleen borders for faster data analysis.

Citation Format: Craig McMannus, Tomek J. Czernuszewicz, Ryan C. Gessner, Jeffrey D. Peterson. High-throughput in vivo monitoring of splenomegaly and tumor burden in a murine breast cancer model [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 4177.
Abstract 4238: ModelingRET-rearranged non-small cell lung cancer (NSCLC): Generation of lung cell progenitors from patient-derived induced pluripotent stem cells (iPSCs)
Authors: Marcoux Paul , Hwang Jinwook , Desterke Christophe , Imeri Jusuf , Griscelli Annelise Bennaceur , Turhan Ali
Published: March 2024

Rearranged during Transfection (RET) oncogenic rearrangements can occur in 1-2% of lung adenocarcinomas. While RET-driven NSCLC models have been developed using various approaches, no model based on patient-derived induced pluripotent stem cells (iPSCs) has been described yet. Patient-derived iPSCs hold great promise for disease modeling. However, generating iPSCs with specific oncogenic drivers, like RET rearrangements, presents challenges due to reprogramming efficiency and genotypic variability within tumors. To address this issue, we aimed to generate lung progenitor cells (LPCs) from patient-derived iPSCs carrying the somatic mutation RETC634Y which is commonly associated with hereditary medullary thyroid carcinoma. Additionally, we have established a RETC634Y knock-in iPSC model to validate the effect of this oncogenic mutation during LPC differentiation. We successfully generated LPCs from RETC634Y iPSCs using a 16-days protocol and showed an overexpression of cancer-associated markers as compared to control iPSCs. Transcriptomic analysis revealed a distinct signature of NSCLC tumor repression, suggesting a lung multilineage lung dedifferentiation, along with an upregulated signature associated with RETC634Ymutation potentially linked to poor NSCLC prognosis. These findings were validated using the RETC634Y knock-in iPSC model, highlighting key cancerous targets such as PROM2 and C1QTNF6, known to be associated with poor prognostic outcomes. Furthermore, the LPCs derived from RETC634Y iPSCs exhibited a positive response to the RET inhibitor Pralsetinib, evidenced by the downregulation of the cancer markers. This study provides a novel off-the-shelf iPSC model of RET-driven NSCLC, paving the way for exploring the molecular mechanisms involved in RET-driven NSCLC to study disease progression and to uncover potential therapeutic targets.

Citation Format: Paul Marcoux, Jinwook Hwang, Christophe Desterke, Jusuf Imeri, Annelise Bennaceur Griscelli, Ali Turhan. ModelingRET-rearranged non-small cell lung cancer (NSCLC): Generation of lung cell progenitors from patient-derived induced pluripotent stem cells (iPSCs) [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 4238.
Abstract 4263: Prostate cancer cell-derived small extracellular vesicles regulate monocyte migration via STEAP4 and promote a monocyte transitional state
Authors: Naranjo Nicole M. , Testa Anna , Yadav Santosh K. , Naik Ulhas P. , Yu Lei , Kelly William K. , Liu Qin , Ding Jianyi , Yang Hushan , Tang Hsin Yao , Verrillo Cecilia E. , Hooper Craig D. , Languino Lucia R.
Published: March 2024

Our group has previously shown that prostate cancer (PrCa)-derived small extracellular vesicles (sEVs) are powerful cell communication mediators as they carry an array of proteins that have the ability to change recipient cell functions. Here, we describe a novel pathway of cancer cell-monocyte communication mediated by sEVs. Since sEVs carry cargoes that alter recipient cell phenotypes, we analyzed via proteomic analysis sEVs released from PC3 PrCa cells. Using CRISPR Cas9 methods, we downregulated IFIT3 (Interferon-induced proteins with tetratricopeptide repeats-3, member of the interferon-stimulated gene family) in PC3 PrCa cell (IFIT3KO). We then isolated sEVs from PC3 or IFIT3KO cells by using differential ultracentrifugation followed by iodixanol density gradient. Our proteomic analysis of IFIT3KO sEVs compared to PC3 sEVs shows that IFIT3 downregulation results in a significant upregulation of a metalloreductase, STEAP4 (six-transmembrane-epithelial antigen of the prostate 4), which is increased in PrCa cells and promotes PrCa cell proliferation and survival. STEAP4 is also known to promote an anti-inflammatory response in monocytes and macrophages. We then, investigated whether PrCa sEVs enriched in STEAP4 have a causal effect on monocyte functions and phenotype by using adhesion and migration assays as well as flow cytometry. Our results show that while all PrCa sEVs stimulate the adhesion of healthy donor or non-metastatic PrCa patient monocytes, only PrCa sEVs expressing STEAP4 increase their migration. In parallel, we provide evidence that all PrCa sEVs affect some of the M2 (CD163 or CD204) and M1 (CD80 or HLA DR) polarization markers analyzed in healthy donor monocytes. We show that there is a transitional state induced by PrCa sEVs in healthy donor monocytes, which occurs in a STEAP4-independent manner. This state mimics the non-metastatic PrCa patient monocyte phenotype. In conclusion, we describe a unique pathway whereby PrCa cell sEVs expressing STEAP4 promote monocyte migration with partial changes to their polarization.

Funding: This study was supported by NCI P01-CA140043, R01-CA224769, Pennsylvania DOH - Cure award to L.R.L

Citation Format: Nicole M. Naranjo, Anna Testa, Santosh K. Yadav, Ulhas P. Naik, Lei Yu, William K. Kelly, Qin Liu, Jianyi Ding, Hushan Yang, Hsin Yao Tang, Cecilia E. Verrillo, Craig D. Hooper, Lucia R. Languino. Prostate cancer cell-derived small extracellular vesicles regulate monocyte migration via STEAP4 and promote a monocyte transitional state [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 4263.
Abstract 4270: Differential expression of the αVβ3 integrin affects small extracellular vesicle cargo and promotes small extracellular vesicle pro-tumorigenic activity in vivo via its downstream effector, NgR2
Authors: Verrillo Cecilia E. , Quaglia Fabio , Naranjo Nicole , Testa Anna , Languino Lucia R.
Published: March 2024

It is known that small extracellular vesicles (sEVs) are released from cancer cells and contribute to cancer progression via crosstalk with recipient cells. These sEVs are being investigated as powerful biomarkers and possible therapeutic agents for prostate cancer (PrCa), which remains the leading cause of cancer death among men in the United States. We have previously reported that sEVs expressing the αVβ3 integrin, a protein upregulated in aggressive neuroendocrine prostate cancer (NEPrCa), contribute to neuroendocrine differentiation (NED) in recipient cells. sEVs used in this study were isolated by iodixanol density gradient and characterized by nanoparticle tracking analysis, immunoblotting, and single vesicle analysis. Our proteomic profile of sEVs containing αVβ3, when compared to control sEVs, shows a downregulation of typical effectors involved in apoptosis and necrosis, and an upregulation of tumor cell survival factors. This subset also contains an αVβ3 downstream effector, NgR2, a member of the Nogo receptor family and a novel marker for NEPrCa. We have previously shown that NgR2 promotes NED and cell motility, and upregulates RhoA, a protein associated with aggressive phenotypes of PrCa. In this study, we show that the expression of NgR2 increases tumor growth in vivo. We also show that the downregulation of NgR2 inhibits tumor growth and NED. Furthermore, we report that sEVs containing αVβ3 are loaded with higher amounts of NgR2 as compared to sEVs that do not express αVβ3. Mechanistically, we demonstrate that sEVs containing NgR2 do not affect the sEV marker profile, but, when injected in vivo intratumorally, they promote tumor growth and induce NED. We confirm that the transfer of NgR2 into recipient cells is sufficient to promote tumor growth and show that NgR2 mimics the effect of sEVs containing αVβ3 since it displays increased growth of NgR2 transfectants in vivo, as compared to control cells. Overall, our results describe a new mechanism mediated by sEVs containing αVβ3 and NgR2 that promotes cancer progression.

Acknowledgements: NIH R01-CA224769; DoD W81XWH2210826

Citation Format: Cecilia E. Verrillo, Fabio Quaglia, Nicole Naranjo, Anna Testa, Lucia R. Languino. Differential expression of the αVβ3 integrin affects small extracellular vesicle cargo and promotes small extracellular vesicle pro-tumorigenic activity in vivo via its downstream effector, NgR2 [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 4270.
Abstract 4326: CDK7/CDK9 mediates transcriptional regulation to prime cancer cell paraptosis
Authors: Chang Ling-Chu , Chiang Shih-Kai , Chen Shuen-Ei
Published: March 2024

The mechanisms underlying progression in cell paraptosis are largely unknown. CPYPP, cyclosporin A, and curcumin incited cytoplasmic vacuolization and induced paraptosis in breast cancer cells. The paraptotic program evolved with reactive oxygen species (ROS) provocation and overactivation of proteostatic dynamics to elicit transcriptional regulation involved in redox homeostasis and proteostasis. Pharmacological and genetic approaches suggested that cyclin-dependent kinase (CDK) 7/9 drives paraptotic progression in a reciprocally-dependent manner with heat shock proteins (HSPs). Proteostatic stress as accumulated cysteine-thiols, HSPs, ubiquitin-proteasome system, endoplasmic reticulum stress, and unfolding protein response, as well as ROS provocation primarily within the nucleus enforced CDK7/CDK9-Rpb1 (RNAPII subunit B1) activation by potentiating its interaction with HSPs and protein kinase R (PKR) in a forward loop to amplify the transcriptional regulation and thereby exacerbate proteotoxicity leading to overt paraptosis. Xenograft mouse with OECM-1 cells further confirmed the paraptotic induction against tumor growth. A novel regulatory paradigm that activation of CDK7/CDK9-Rpb1 by nuclear proteostatic stress mediates transcriptional regulation to prime cancer cell paraptosis therefore was concluded.

Citation Format: Ling-Chu Chang, Shih-Kai Chiang, Shuen-Ei Chen. CDK7/CDK9 mediates transcriptional regulation to prime cancer cell paraptosis [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 4326.