bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract LB296: Human CYP1B1 enhances cancer progression through induction of Sp1 via DNMT-mediated epigenetic regulation of miR-375
Authors: Chun Young-Jin , Kwon Yeo-Jung , Kwon Tae-Uk
Published: April 2024

Human cytochrome P450 1B1 (CYP1B1) is a major catalytic enzyme for metabolism of 17β-estradiol (E2) to catechol estrogens, mainly carcinogenic metabolite 4-hydroxyestradiol (4-OHE2). To identify the unknown molecular mechanism for cancer progression induced by CYP1B1, we studied the role of CYP1B1 in human tumor cells, MCF-7, MDA-MB-231, and HeLa cells. Suppression of CYP1B1 by shRNA significantly reduced cancer cell viability and invasion. Clinical data from cancer patients showed that high level of CYP1B1 expression resulted in relatively lower survival rate. Interestingly, overexpression of CYP1B1 markedly activated Wnt/β-catenin signaling and EMT process, and suppression of specificity protein 1 (Sp1) by siRNA, an well-known transcription factor, demolished the promoting effects of CYP1B1 on cancer progression. To investigate the correlation between CYP1B1 and Sp1, we analyzed the clinical data from breast and cervical cancer patients and the results showed the positive correlation between two genes. Furthermore, TMS (tetramethoxystilbene), a specific CYP1B1 inhibitor, diminished the induction of Sp1 by CYP1B1, and 4-OHE2 exceedingly promoted the expression level of Sp1. Surprisingly, miR-375, known as an oncogenic microRNA, substantially decreased by 4-OHE2 and CYP1B1 overexpression in CYP1B1-transgenic (TG) mice. Methylation specific assay revealed that CYP1B1 suppressed miR-375 expression through induction of hyper-methylation on pre-miR-375. In addition, epigenetic regulation of miR-375 by CYP1B1 was executed via induction of DNA methyltransferases (DNMTs), DNMT1, 3a, and 3b. Enhanced expression level of Sp1 by 4-OHE2 was significantly deteriorated by 5-aza-dC, a DNMT inhibitor. Taken together, our data suggest that CYP1B1 enhances cancer progression through induction of cancer cell proliferation and invasion via DNMT-mediated epigenetic regulation of miR-375 and further promotion of Sp1 expression.

Citation Format: Young-Jin Chun, Yeo-Jung Kwon, Tae-Uk Kwon. Human CYP1B1 enhances cancer progression through induction of Sp1 via DNMT-mediated epigenetic regulation of miR-375 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB296.
Abstract LB298: Simultaneous reprogramming of glioblastoma tumor cells and tumor-associated macrophages by tumor-suppressive microRNA
Authors: Nguyen Grace , Noh MinHye , Dai Yulin , Zhao Zhongming , Yoo Ji Young , Lee Tae Jin
Published: April 2024

Therapeutic outcomes in glioblastoma (GBM) patients remain dismal due to its resistance to conventional therapies. Tumor-supportive tumor microenvironment (TME) that is educated by tumor cells through immune editing is not properly primed for the treatment. Targeted reprogramming of both tumor cells and tumor-associated macrophages (TAMs) is expected to prime the tumor cells and the immunosuppressive TME. Tumor suppressive microRNAs (miRNAs) have been proposed as the most suitable therapeutic target to perform the tumor reprogramming role. We recently identified miR-138 as a putative tumor suppressive miRNA that can reprogram GBM tumor. However, achieving the simultaneous targeted reprogramming of two distinct cell types is a complex challenge, demanding a selective delivery system to minimize adverse side effects. Previously, we demonstrated that extracellular vesicles (EVs) can serve as carriers for the selective delivery of small noncoding therapeutic RNAs into cancer cells through the EV surface labeling with cancer-targeting ligands. Here, we report that the trypsin digestion of EV surface can enhance their surface labeling efficiency with cancer targeting ligands, such as folate, with favorable bio-distribution and pharmacokinetic profiles in GBM mice model. The folate-labeled trypsinized EVs demonstrated a potential to selectively target folate receptor (FR) positive GBM cells and TAMs both in vitro and in vivo. The selective targeting of folate-labeled trypsinized EVs led to the targeted delivery of miR-138 into both GBM tumor cells and TAMs, achieving anti-tumor efficacy. Mechanism of action studies revealed that the ectopically delivered miR-138 inhibits its previously identified known target genes to reprogram tumor cell proliferation and macrophage polarization. To our knowledge, this is the first preclinical study attempting to simultaneously modulate tumor cells and innate immunity by delivering tumor suppressive miR-138 using the trypsinized EV-based RNA delivery system for the GBM treatment. Our study results can be rapidly translated into human clinical trials in combination with current immunotherapies.

Citation Format: Grace Nguyen, MinHye Noh, Yulin Dai, Zhongming Zhao, Ji Young Yoo, Tae Jin Lee. Simultaneous reprogramming of glioblastoma tumor cells and tumor-associated macrophages by tumor-suppressive microRNA [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB298.
Abstract LB299: Dihydrouridine synthase 2 sustains levels of tRNACys and prevents ferroptosis in lung cancer
Authors: Draycott Austin , Wang Matthew C. , Saucedo Diana Martínez , Escobar-Hoyos Luisa , Gilbert Wendy
Published: April 2024

Dihydrouridine is a universally conserved tRNA modification installed by enzymes that are important for human health. High expression of dihydrouridine synthase 2 (DUS2) predicts poor patient outcomes in lung adenocarcinoma (LUAD) for reasons that are not yet clear. Here, we show in human cells and mouse xenografts that DUS2 suppresses ferroptosis, a metal-dependent non-apoptotic form of cell death that is emerging as a therapeutic target in lung cancer. Elevated DUS2 correlates with resistance to ferroptosis inducers and loss of DUS2 causes increased sensitivity with concomitant accumulation of toxic lipid peroxides. Mechanistically, DUS2 is required to maintain tRNA CysGCA levels, supporting translation of cysteine-rich proteins including metallothioneins, key regulators of metal and redox homeostasis Notably, DUS2 KO cells cannot sustain normal levels of metallothioneins, a class of very cysteine rich proteins that serve as key regulators of both metal and redox homeostasis. Accordingly, DUS2 knockout cells are more susceptible to zinc intoxication and have lower levels of reduced glutathione, which partially explains their sensitivity to ferroptosis. Our findings demonstrate that DUS2 is required to support tRNACys levels and fend off ferroptosis in lung cancer cells. This highlights that individual tRNA substrates can play an outsized role in the biological functions of tRNA modifying enzymes, and demonstrates the therapeutic potential of targeting DUS2 in cancer.

Citation Format: Austin Draycott, Matthew C. Wang, Diana Martínez Saucedo, Luisa Escobar-Hoyos, Wendy Gilbert. Dihydrouridine synthase 2 sustains levels of tRNACys and prevents ferroptosis in lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB299.
Abstract LB301: BRAFV600E drives WNT signalling in colorectal cancer via aberrant DNA methylation
Authors: Bouazzaoui Layla El , Bugter Jeroen M. , Küçükköse Emre , Verheem André , Post Jasmin B. , Fenderico Nicola , Rinkes Inne H. Borel , Snippert Hugo J. , Maurice Madelon M. , Kranenburg Onno
Published: April 2024

Objective: The BRAF V600E mutation drives the generation of an aggressive subtype of colorectal cancer (CRC). Although activation of WNT signalling is a generic hallmark of CRC, mutations in APC are uncommon in BRAF V600E-mutant CRC. Instead, mutations in RNF43 are the suspected WNT signalling driving event in these tumours. Here, we aimed to uncover how the WNT pathway is activated in BRAF V600E-mutant colon cancer.

Design: CRISPR-LbCpf1-corrected BRAF (V600E) and RNF43 (P441fs) organoids were analysed for their growth potential in the presence or absence of growth factors, for their ability to form tumours, and by immunoblotting, RNA sequencing, and DNA methylation assays.

Results: BRAF E600V organoids regained dependency on epidermal growth factor (EGF) receptor signalling for ERK pathway activation and proliferation, and completely lost tumorigenic potential. Correction of BRAF V600E, but not RNF43 P441fs, caused suppression of WNT target genes, while genes reflecting epithelial differentiation and negative regulators of WNT signalling were upregulated in BRAF E600V organoids. DNA methylation analysis revealed promoter hypermethylation of WNT antagonist genes in BRAF V600E organoids. Gene body hypermethylation, associated with transcriptional upregulation, was observed in key WNT-driven intestinal stem cell marker genes LGR5 and EPHB2, and in the WNT-effector TCF4. Treatment of BRAF V600E organoids with the DNA demethylating agent 5-aza-2′-deoxycytidine resulted in upregulation of WNT antagonist genes and a marked decrease in WNT target gene expression.

Conclusions: BRAFV600E, rather than mutant RNF43, is a prominent force behind WNT pathway activation, and is essential for maintaining tumorigenic capacity. BRAFV600E causes widespread dysregulation of DNA methylation leading to activation of WNT signalling.

Citation Format: Layla El Bouazzaoui, Jeroen M. Bugter, Emre Küçükköse, André Verheem, Jasmin B. Post, Nicola Fenderico, Inne H. Borel Rinkes, Hugo J. Snippert, Madelon M. Maurice, Onno Kranenburg. BRAFV600E drives WNT signalling in colorectal cancer via aberrant DNA methylation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB301.
Abstract LB302: circIPO7 dissociates caprin-1 from ribosomes and inhibits gastric cancer cell proliferation by suppressing EGFR and mTOR
Authors: Niu Liling , Liu Jing , Li Hui
Published: April 2024

circIPO7 dissociates caprin-1 from ribosomes and inhibits gastric cancer cell proliferation by suppressing EGFR and mTORLiling Niu, Jing Liu, Hui Li*Purpose: Circular RNAs (circRNAs) are vital participant of various pathophysiological processes through unique mechanisms. We previously reported that circIPO7 (circBase ID: hsa_-circ_0005092) was positively associated with postoperative recurrence of gastric cancer (GC). In the present study, we aimed to explore the biological function of circIPO7 in GC development. Methods: CCK-8, clone formation, Edu proliferation assay and xenograft model were used to analyze the effects of circIPO7 and caprin-1 on the cell proliferation and tumor growth in vivo and in vitro. Mass spectrometry, RNA pull down, RIP and RNA-FISH experiments were used to identify the co-localization and interaction between caprin-1 and circIPO7. RIP sequencing was used to analyze the mRNAs binding with caprin-1. Rescue experiment was conducted to evaluate the translational regulation of circIPO7 on caprin-1 downstream effector molecule.Results: circIPO7 was downregulated in GC tissues and cells compared to paracarcinoma tissues and normal epithelial cells. circIPO7 overexpression significantly suppressed GC cell proliferation in vitro and in vivo. Mechanistically, circIPO7 directly binds with caprin-1, an RNA-binding protein involved in mRNA translation, sharing overlapping binding sites with G3BP1. Thus, the complex containing overexpressed circIPO7 blocked the caprin-1-G3BP1 interaction and dissociated caprin-1 and its target mRNAs (EGFR and mTOR) from ribosomes, resulting in their translational inhibition, followed by PI3K/AKT/mTOR pathway inactivation.Conclusion: We demonstrate that circIPO7 serves as an RBP sponge for caprin-1, inhibits the translation of downstream proliferation-related mRNAs, and ultimately suppresses malignant cell proliferation. Taken together, these results suggest that circIPO7 may be a potential therapeutic target for GC treatment.

Citation Format: Liling Niu, Jing Liu, Hui Li. circIPO7 dissociates caprin-1 from ribosomes and inhibits gastric cancer cell proliferation by suppressing EGFR and mTOR [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB302.
Abstract LB306: PD-L1-targeted radioimmunethrapeutics combined with oncolytic virus for treatment of pancreatic cancer
Authors: Yoon Arum , Yun Chae-Ok , Kim Jin Su
Published: April 2024

Pancreatic cancer is difficult to treat, and the first line treatment provide only modest survival benefits to patients due to its highly desmoplastic and immune-desert phenotype. To overcome these hurdles, PD-L1-targeted radioimmunotherapy (RIT) using lutetium-177-labelled atezolizumab (177Lu-aPD-L1) combined with an oncolytic virus, named HY-oAd, that co-expresses three therapeutic genes (interleukin-12, granulocyte-macrophage colony-stimulating factor and relaxin) was investigated. HY-oAd treatment was shown to elevate PD-L1 expression level and promoted degradation of extracellular matrix (ECM) of pancreatic tumors, resulting in increased aPD-L1 or 64Cu-aPD-L1 accumulation in tumor tissues. Moreover, HY-oAd in combination with either aPD-L1 or 177Lu-aPD-L1 elicited more potent antitumor effect against the pancreatic tumors than respective monotherapy in pancreatic tumor models. The potent antitumor effect of HY-oAd+aPD-L1 combination therapy can lead to superior intratumoral infiltration and activation of dendritic cells and CD4+ or CD8+ T cells over the respective monotherapy. Collectively, our findings demonstrate that HY-oAd can potentiate PD-L1-targeted RIT through PD-L1 upregulation and ECM degradation, thus resulting in synergistic antitumor efficacy and antitumor immune response.

Citation Format: Arum Yoon, Chae-Ok Yun, Jin Su Kim. PD-L1-targeted radioimmunethrapeutics combined with oncolytic virus for treatment of pancreatic cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB306.
Abstract LB313: Immunosuppressive effect of tumor-infiltrating IL-22 receptor-expressing myeloid cells in early-stage pancreatic ductal adenocarcinoma
Authors: Sung Yoolim , Kim Ji-Eun , Min Hyo-Jin , Chung Soo-Hyun , Kim Seong Who , Chang Eun-Ju
Published: April 2024

Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive malignancy with a poor survival rate, largely due to the lack of diagnostic biomarker for early detection. Here, we found enriched IL-10R2+/IL-22R1+ myeloid cells in peripheral blood and specifically PDAC tissues respectively using xenograft/orthotropic PDAC mouse models. The subcutaneous injection of PDAC cell line in mouse showed a positive correlation of pancreatic tumor growth with increased IL-10R2+/IL-22R1+ myeloid cells by flow cytometry. We also verified that IL-10R2+CD45+ and IL-22R1+CD45+ myeloid cells were infiltrated in tumor tissues after 2 weeks and 3 weeks of injection in orthotropic murine PDAC model. Notably, the IL-10R2+IL-22R1+ cells were highly detected in tumor tissues after 7 days of injection, an earlier time point of PDAC progression. To define whether these cells have immunosuppressive functions to contribute further PDAC progression, IL-10R2+/IL-22R1+ myeloid cells were sorted from splenocytes after 3 days of tumor implantation and co-cultured with T cells in the presence of T cell receptor triggering. The proliferation and cytotoxicity of CD8+ T cells were alleviated by co-culture with IL-10R2+, IL-22R1+, or IL-10R2+IL-22R1+ myeloid cells, compared to that with IL-10R2-IL-22R1- cells. In addition, the population of regulatory T cells was increased when they were co-cultured with IL-22R1+ myeloid cells. Furthermore, the proliferation of human T cells in vitro was also inhibited by co-culture with IL-10R2+/IL-22R1+ myeloid cells from human peripheral blood, indicating the immunosuppressive function of IL-10R2+/IL-22R1+ cell population. Therefore, IL-10R2+/IL-22R1+ myeloid cell population could be a possible promising early detection marker for PDAC, contributing to the non-immunogenic features of tumor microenvironment during PDAC progression.

Citation Format: Yoolim Sung, Ji-Eun Kim, Hyo-Jin Min, Soo-Hyun Chung, Seong Who Kim, Eun-Ju Chang. Immunosuppressive effect of tumor-infiltrating IL-22 receptor-expressing myeloid cells in early-stage pancreatic ductal adenocarcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB313.
Abstract LB364: Generation and Application of a Robust Humanized Mouse Tumor Model System for Evaluation of NK-Targeting Therapeutics
Authors: Lu Feng , Ding Weiqun , Yang Guangliang , Jia Yaoqing , Wang Zhaoxiang , Yuan Xusheng , Yin Ming , Yang Zhijian , Yang WenQing
Published: April 2024

With the new waves of anti-tumor immunotherapy development, novel immunotherapies based on NK cells have emerged and advanced rapidly. Considering the inherent mechanisms of NK cells, various strategies are employed in tumor immunotherapy to maximize the efficacy of NK cells, including the following: 1) immune checkpoint inhibitors to relieve NK cell inhibition signals; 2) activation of NK cell activity; 3) targeted antibody therapy for tumor cell killing via antibody-dependent cellular cytotoxicity (ADCC), and 4) cell therapy, such as CAR-NK. Although numerous NK-targeting immune therapeutics or various NK-modulating modalities have been developed or advanced toward clinical trials, there is a lack of clinically relevant preclinical animal models that can be widely accepted for the evaluation of NK-modulating agents, particularly for models that involve functional human NK cells in the test system. This study generated a humanized mouse tumor model system which involves specific reconstitution of functional and durable human NK cells in a murine system, providing a clinically relevant tumor microenvironment. We first engineered a stable monoclonal feeder cell line in vitro to expand NK cells isolated from human peripheral blood mononuclear cells (hPBMCs) using magnetic bead separation. Using this approach, the human primary NK cells were robustly and consistently amplified (up to hundreds of fold) while maintaining their purity and functionality. When compared with primary NK cells using in vitro immune assays including ADCC and FACs, the expanded NK cells showed comparable results as the parental cells. In vivo experimental results indicated that a durable and functional NK reconstitution can be established in tumor-bearing severely immune deficient mice expressing hIL-15. Furthermore, this NK-humanized tumor model system was proven to respond to standard of care (SOC) NK-targeting drugs. In summary, this novel NK humanized in vivo model may represent an effective preclinical tool for assessing NK-modulating drugs, with the hope of facilitating the development process of novel immune therapeutics employing both adaptive and innate immunity.

Citation Format: Feng Lu, Weiqun Ding, Guangliang Yang, Yaoqing Jia, Zhaoxiang Wang, Xusheng Yuan, Ming Yin, Zhijian Yang, WenQing Yang. Generation and Application of a Robust Humanized Mouse Tumor Model System for Evaluation of NK-Targeting Therapeutics [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB364.
Abstract LB367: Effects of modulation of ERAP1 activity in antigen processing and presentation
Authors: Mourid Shami Alvarez , James Edward , Guglietta Dario , Reeves Emma
Published: April 2024

ERAP1 is an enzyme that plays a key role in the antigen processing and presentation pathway as an editor of the peptide repertoire, allowing for the binding of neoantigens to MHC I. ERAP1 is polymorphic, with the different allelic variants showing various degrees of peptide trimming function expressed in humans. However, the trimming mechanism by which ERAP1 trims peptides is still not fully understood. The purpose of the study is to characterize the effect of the different ERAP1 variants and their inhibition on the peptide repertoire presented by tumor cells, enabling us to gain valuable insights into how this process works. This characterization will also enhance the pharmacological modulation of ERAP1, which has already been proven to promote T cell and NK-mediated anti-tumor cytotoxic response. By specifically targeting the activity levels of the ERAP1 variant expressed, we can adopt a personalized approach that maximizes the potential production of neoantigens, crucial for activating an anti-tumor immune response. We CRISPR knocked out the ERAP1 gene in the CT26 cell line and assessed the MHC I kinetics and stability by investigating the dissociation of pMHC complexes at the cell surface, using a Brefeldin-A decay assay and an acid-stripping test compared to wild-type. The assessment of MHC I assembly and cell surface expression kinetics showed higher MHC I in the ERAP1 KO cell line, highlighting that the lack of ERAP1 translated into a faster recovery time of peptide/MHC complexes at the cell surface. After assessing the kinetics, we re-expressed different human ERAP1 allotypes in CT26 ERAP1KO cell line through retroviral transduction and characterized MHC I expression levels through flow cytometry. Interestingly, MHC I expression levels varied across the transduced samples, with specific variants showing much higher expression levels indicating more peptide availability for loading onto the MHC molecules. Immunopeptidomic analysis comparing the WT, ERAP1 KO and the CT26 human ERAP1 transduced cell lines, showed distinct subsets of neoantigens presented in the KO cell line. ERAP1 plays a significant role in the assembly and recovery of peptide/MHC complexes. The reintroduction of different ERAP1 allelic variants greatly alters MHC I expression levels suggesting the formation of new peptide-MHC complexes responsible for the increase in MHC I expression. Modulation of ERAP1 activity significantly alters the presented peptide repertoire , uncovering neoantigens which are potentially immunogenic.

Citation Format: Shami Alvarez Mourid, Edward James, Dario Guglietta, Emma Reeves. Effects of modulation of ERAP1 activity in antigen processing and presentation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB367.
Abstract LB370: Exploring SLC35B family genes in colorectal carcinoma: Bioinformatics and functional insights into prognosis and therapy
Authors: Chang Yu-Jia , Yang Chang-Chun , Lee Cheng-Chin , Huang Chien-Yu
Published: April 2024

Colorectal carcinoma (CRC) poses a significant health challenge, with recent therapeutic advances yet to substantially improve long-term patient survival. Central to this study is the SLC35B gene family (SLC35B1-4), which encodes nucleotide sugar transporters essential to cellular membranes. Emerging research highlights a link between these transporters' dysfunction and the development and progression of tumors, yet the specific role of the SLC35B family in CRC remains unclear. Our investigation delves into the function of SLC35B genes in CRC, utilizing an integrated bioinformatics approach with databases like GENT2, TCGA, UALCAN, cBioportal, TIMER, and Kaplan-Meier plotter. Our analysis reveals a notable upregulation of SLC35B1/2/4 mRNA in CRC tissues compared to adjacent non-tumor tissues, with a concurrent downregulation of SLC35B3. Promoter methylation analysis shows increased methylation for SLC35B1/3/4, while SLC35B2 demonstrates decreased methylation. According to GEO and TCGA data, CRC patients exhibiting high SLC35B4 expression face lower survival rates. Multivariate Cox regression analysis confirms high SLC35B4 expression as an independent risk factor. Further, SLC35B4 expression correlates with increased infiltration of immune cells, particularly macrophages, and aligns positively with immune checkpoints such as CD274 and HAVCR2. In vitro assays link SLC35B4 to enhanced cancer cell proliferation, invasion, migration, and epithelial-mesenchymal transition (EMT). In vivo, SLC35B4 knockdown leads to reduced tumor growth in mouse xenograft models. RNA sequencing identifies 241 genes differentially expressed in SLC35B4 knockdown compared to control cells, with Gene Set Enrichment Analysis (GSEA) associating SLC35B4 with the PI3K-Akt signaling pathway. In summary, our research sheds light on the SLC35B gene family's role in CRC, especially SLC35B4, highlighting its potential as both a prognostic marker and a therapeutic target in CRC, particularly through its involvement in the PI3K-Akt signaling pathway.

Citation Format: Yu-Jia Chang, Chang-Chun Yang, Cheng-Chin Lee, Chien-Yu Huang. Exploring SLC35B family genes in colorectal carcinoma: Bioinformatics and functional insights into prognosis and therapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB370.
Abstract LB386: Weakly-supervised prediction of tumor infiltrating lymphocytes per high power field from colorectal cancer histopathology slides using regression transformers
Authors: Nahhas Omar S. El , Bonner Joseph D. , Greenson Joel K. , Schmolze Daniel B. , Shaktah Lawrence , Salazar Jonathan , Reynaga Lorena , Lindsey Sidney , Lu Jenny , Moreno Victor , Schmit Stephanie L. , Tsai Ya-Yu , Hamilton Stanley R. , Rennert Gad , Kather Jakob N. , Gruber Stephen B.
Published: April 2024

Tumor infiltrating lymphocytes (TILs)-based biomarkers have emerged as a robust method for predicting treatment efficacy and outcome in colorectal cancer (CRC). However, the quantification of TILs remains a strenuous task for pathologists and is susceptible to inter-pathologist variations. Deep learning (DL) can predict cancer biomarkers directly from routine hematoxylin and eosin (H&E) pathology slides, enabling the automated and consistent quantification of TILs for clinical decision-making. Our study focuses on the prediction of TILs per high-power field (HPF) on two large cohorts of CRC patients. We developed a weakly-supervised, transformer-based deep regression model to predict TILs per HPF from routine H&E-stained histology slides. We trained the model using 5-fold cross-validation on a large cohort of CRC patients (n=1,738), and validated its performance on an external cohort of CRC patients (n=223). The model was evaluated using the Pearson’s correlation coefficient r. Moreover, pathologist-determined TILs per HPF was categorized into low (<2) and high (≥2), enabling evaluation via the area under the receiver operating characteristic curve (AUROC). Our model achieved a significant correlation coefficient of 0.60 (p<0.0001) for the predicted TILs per HPF in the holdout test sets of the internal cohort, and a significant correlation coefficient of 0.57 (p<0.0001) on the external validation cohort. Using the thresholds for low and high TILs per HPF, we found that the model accurately predicted the presence of high TILs per HPF in both the internal and external test cohorts, yielding AUROCs of 0.76 and 0.81, respectively. These findings underscore the efficacy of our deep learning model in predicting TILs per HPF from routine pathology slides. This approach holds promise for cost-effective, efficient and uniform quantification of TILs per HPF in CRC, potentially across various cancer types.

Citation Format: Omar S. El Nahhas, Joseph D. Bonner, Joel K. Greenson, Daniel B. Schmolze, Lawrence Shaktah, Jonathan Salazar, Lorena Reynaga, Sidney Lindsey, Jenny Lu, Victor Moreno, Stephanie L. Schmit, Ya-Yu Tsai, Stanley R. Hamilton, Gad Rennert, Jakob N. Kather, Stephen B. Gruber. Weakly-supervised prediction of tumor infiltrating lymphocytes per high power field from colorectal cancer histopathology slides using regression transformers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB386.
Abstract LB410: Contrasting roles of different mismatch repair proteins in basal like breast cancer
Authors: Tithi Tanzia Islam , Mo Jiao , Zhang Weizhou
Published: April 2024

The mismatch repair (MMR) pathway is known as a tumor suppressive pathway and genes involved in MMR are commonly mutated in hereditary colorectal or other cancer types. However, the function of MMR genes/proteins in breast cancer progression and metastasis are largely unknown. We found that MSH2, but not MLH1, is highly enriched in basal-like breast cancer (BLBC) and that its protein expression is inversely correlated with overall survival time (OS). MSH2 expression is frequently elevated due to genomic amplification or gain-of-expression in BLBC, which results in increased MSH2 protein to pair with MSH6 (collectively referred to as MutSα). Genetic deletion of MSH2 or MLH1 results in a contrasting phenotype in metastasis, with MSH2-deletion leading to reduced metastasis and MLH1-deletion to enhanced liver or lung metastasis. Mechanistically, MSH2-deletion induces the expression of a panel of chemokines in BLBC via epigenetic and/or transcriptional regulation, which leads to an immune reactive tumor microenvironment (TME) and elevated immune cell infiltrations. MLH1 is not correlated with chemokine expression and/or immune cell infiltration in BLBC, but its deletion results in strong accumulation of neutrophils that are known for metastasis promotion. Our study supports the differential functions of MSH2 and MLH1 in BLBC progression and metastasis, which challenges the paradigm of the MMR pathway as a universal tumor suppressive mechanism.

Citation Format: Tanzia Islam Tithi, Jiao Mo, Weizhou Zhang. Contrasting roles of different mismatch repair proteins in basal like breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB410.
Abstract LB411: Investigating the dependency of androgen receptor-positive prostate cancer on class I myosins
Authors: Kadam Anoushka , Kumar Shivani , Vakkala Varsha , Kumar Rajendra , De Marzo Angelo M. , Pearce Edward J. , Sena Laura A.
Published: April 2024

Prostate adenocarcinoma is characterized by high expression and activity of the androgen receptor (AR). AR is a nuclear hormone receptor that stimulates anabolic cell metabolism. We hypothesized that the high activity of AR in prostate cancer creates unique dependencies on cellular machinery to support this high rate of anabolism. We observed that androgen treatment of patients with metastatic castration-resistant prostate cancer resulted in increased abundance of MYO1E, a class I myosin that facilitates intracellular vesicular trafficking, in tumor biopsies. Similarly, MYO1E protein increased in AR+ prostate cancer cell lines upon treatment with androgens. Notably, a specific small molecule inhibitor of MYO1E, pentachloropseudilin (PClP), induced cell death of AR-positive prostate cancer cell lines with an IC50 of 2-4uM, but was non-toxic to AR-negative prostate cancer cell lines. Expression of AR in these AR-negative lines conferred sensitivity to PClP, while deletion of AR in an AR-positive line conferred resistance to PClP, indicating that AR expression was required and sufficient for sensitivity of prostate cancer cell lines to PClP. Previous studies have suggested that AR globally increases protein synthesis and proteotoxic stress, and we asked whether this may create a dependency on MYO1E for secretion of protein-containing vesicles to manage proteotoxic stress. Initial experiments suggest that AR increases global rates of protein synthesis, as assessed by puromycin-incorporation assays, and inhibition of MYO1E increases phosphorylation of EIF2A, suggestive of activation of the integrated stress response. Further experiments will determine the essential function of MYO1E in AR-positive prostate cancer. Altogether our studies suggest that the class I myosin MYO1E is an essential protein in AR-positive cell lines and may represent a novel drug target for prostate adenocarcinoma.

Citation Format: Anoushka Kadam, Shivani Kumar, Varsha Vakkala, Rajendra Kumar, Angelo M. De Marzo, Edward J. Pearce, Laura A. Sena. Investigating the dependency of androgen receptor-positive prostate cancer on class I myosins [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB411.
Abstract LB446: Decoding the mechanism of metastasis: A novel CAF-therapy that blocks the tumor microenvironment and reverses metastatic traits in all solid tumors
Authors: Prieto Benjamin , Núñez Muriel , Cerdfa Valentina I. , Cerda-Infante Javier
Published: April 2024

Progression and metastatic spreading of cancer cells are modulated by the carcinoma-associated fibroblasts (CAFs) within the primary tumor microenvironment in solid tumors. However, the mechanisms through which CAFs exert their pro-metastatic effects on cancer cells remain unknown. In this study, we have developed a small molecule that blocks Neuropilin-1 signaling in metastatic CAFs (mCAFs), reversing the mechanisms that promote metastasis in prostate, breast, colorectal and pancreatic cancer. To address these critical needs, in this study, we sought to assess the potential role of proteoglican neuropilin 1 (PG-NRP1) signaling in the maintenance of the activated CAF phenotype.

Our results by gene expression profile, qPCR, WB, and ELISA indicate that CAFs isolated from primary tumors of metastatic patients (mCAFs) are functionally different from CAFs isolated from primary tumors of non-metastatic patients, promoting metastasis traits of cancer cells. Among the most prominent differences is an increased PG-NRP1 expression.

siRNA studies demonstrated that the knockdown of NRP-1 in mCAFs showed the reversion of the activated phenotype, evaluated by the activation markers a-SMA, Tenascin C, and Fibronectin. Furthermore, conditioned media from PG-NRP1-siRNA-mCAFs failed to increase cancer cells' metastasis traits (migration and invasion) in vitro and tumor progression in vivo. Furthermore, we engineered a small molecule designed to bind PG-NRP1 in mCAFs. Our findings, demonstrate in vitro and in vivo models that the inhibition of PG-NRP1 impedes tumor growth and metastatic dissemination of cancer cells in spontaneous metastasis assay.

We designed and validated, using in vivo models, an inhibitor that blocks NRP1-mCAF. Our research demonstrates that blocking PG-NRP1 in mCAF, with a small molecule, is a transversal therapeutic strategy to prevent progression and metastatic spread in solid cancer tumors.

Citation Format: Benjamin Prieto, Muriel Núñez, Valentina I. Cerdfa, Javier Cerda-Infante. Decoding the mechanism of metastasis: A novel CAF-therapy that blocks the tumor microenvironment and reverses metastatic traits in all solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB446.
Abstract ND01: ABBV-303: A novel NK and CD8 T cell engager specific for c-Met-expressing tumors
Authors: Stone Jennifer , Fish Kamonwan Pear , Ashok Devika , McKay Laura , Akhand Saeed , Zhao Weilong , Wu Si , Makkouk Amani , Cosgrove Cormac , Ellis Paul , Peetz David , Shee Stephanie , Peterson Richard , Anderson Shelby , Chervin Adam , Stevenson Claudina , Uziel Tamar , Reilly Edward
Published: April 2024

Natural killer (NK) cell redirecting therapies are emerging as promising “off the shelf” treatments for cancer without the safety issues associated with T cell directed therapies. ABBV-303 is a novel c-Met targeted multispecific NK cell engager based on Dragonfly Therapeutics’ TriNKET® technology. ABBV-303 includes three functional arms: (1) a c-Met binding scFv based on ABT-700, common to c-Met-targeting antibody-drug conjugates ABBV-400 and Teliso-V; (2) a Fab arm that binds NKG2D, a stimulatory receptor expressed by NK cells and activated CD8+ T cells; and (3) a heterodimeric IgG1 Fc which binds CD16a on NK cells and links the other two binding moieties. ABBV-303 binding to NKG2D and CD16a results in redirection of both innate (NK cells) and adaptive (CD8+ T cells) immune cells to lyse c-Met expressing tumor cells. Treatment of peripheral blood mononuclear cells (PBMCs) from healthy donors and cancer patients with ABBV-303 in the presence of c-Met+ tumor cells stimulates NK and CD8+ T cells as demonstrated by modulation of activation-associated surface proteins and release of soluble factors. ABBV-303 drives sub-nanomolar redirected killing potency against tumor cells expressing a broad range of c-Met. Additionally, anti-tumor activity of ABBV-303 has been demonstrated against established xenografts in CD34 humanized NSG mice. NK and CD8+ T cell activity in response to ABBV-303 has been observed in c-Met-expressing fresh patient tumor explants. A benign safety profile was observed in non-human primates through three repeat doses up to 150 mg/kg given every two weeks, with antibody-like exposures and a serum half-life around 8 days. Based on these findings, the First in Human ABBV-303 study will initiate in 1H 2024 in solid tumors as a monotherapy and in combination with an anti-PD-1 checkpoint inhibitor.

All authors are current employees of AbbVie. The design, study conduct, and financial support for this research were provided by AbbVie. AbbVie participated in the interpretation of data, review, and approval of the publication.

Citation Format: Jennifer Stone, Kamonwan Pear Fish, Devika Ashok, Laura McKay, Saeed Akhand, Weilong Zhao, Si Wu, Amani Makkouk, Cormac Cosgrove, Paul Ellis, David Peetz, Stephanie Shee, Richard Peterson II, Shelby Anderson, Adam Chervin, Claudina Stevenson, Tamar Uziel, Edward Reilly. ABBV-303: A novel NK and CD8 T cell engager specific for c-Met-expressing tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr ND01.
Abstract ND05: The discovery of ARV-393, a potent, orally bioavailable BCL6 targeting PROTAC® for the treatment of Non-Hodgkin’s Lymphoma
Authors: Sherman Dan
Published: April 2024

Discovery of ARV-393, a potent, orally bioavailable BCL6 targeting PROTAC® for the treatment of Non-Hodgkin’s Lymphoma (NHL)Dan Sherman, Sheryl M. Gough, Lynn DeCarr, Sarah Eaton, Mark Bookbinder, Jennifer Pizzano, Elizabeth Bortolon, John Corradi, Rashaun Wilson, Daniel Rogoz, Ram Lingamaneni, Wei Zhang, Michelle Zhang, Xin Chen, Gan Wang, Hanqing Dong, Michael Berlin, Keith R. Hornberger, Lawrence Snyder, Achal Pashine and Ian Taylor.

Arvinas, Inc., 5 Science Park, New Haven, CT, USA.

Approximately 18,000 cases of Diffuse large B-cell lymphomas (DLBCL) are diagnosed worldwide per year making this cancer the most prevalent (30%) of the non-Hodgkin’s Lymphomas (NHL). Despite the success of R-CHOP treatment, approximately 40% of patients are refractory or relapse. While much progress has been made with CAR-Ts and bi-specific antibodies following frontline therapy in recent years, there remains a need for an orally bioavailable small-molecule that targets molecular drivers of NHL. The BCL6 transcription factor has long been known as an oncogenic driver of B-cell malignancy. The BCL6 gene has been found to be translocated and/or mutated resulting in deregulation of its expression, predominantly in DLBCL and Burkitt’s lymphoma (BL). The deregulated expression and scaffolding role of BCL6 in the transcriptional repressor complex make it an ideal target for the PROteolysis Targeting Chimera (PROTAC®) technology with one BCL6 degrader recently entering Phase 1 trials. We undertook a medicinal chemistry campaign to identify a BCL6-targeting PROTAC®. This effort identified ARV-393, an orally bioavailable PROTAC® that recruits BCL6 and the E3 ligase cereblon to rapidly degrade BCL6 via the cell’s natural ubiquitin proteasome system. ARV-393 is potent, demonstrating DC50 and GI50 values <1 nM in numerous DLBCL and BL cell lines. This agent demonstrates deep BCL6 degradation in vitro and in vivo, resulting in excellent TGI in several tumor xenograft models supporting a first-in-human trial in 1H 2024. We will present the chemical structure of ARV-393 and selected pre-clinical data.

Citation Format: Dan Sherman. The discovery of ARV-393, a potent, orally bioavailable BCL6 targeting PROTAC® for the treatment of Non-Hodgkin’s Lymphoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr ND05.
Abstract PL04-03: Metastasis aggressiveness: A function of metabolite signaling
Authors: Fendt Sarah-Maria
Published: April 2024

Metastasis formation is the leading cause of death in cancer patients. Yet, the molecular mechanisms responsible for the aggressiveness of metastases remain largely unknown. We used experimental metastasis mouse models and samples from patients with breast cancer to study metastases aggressiveness. We discovered that the aggressiveness of cancer cells in lung metastases was driven by an alternative translational program that was regulated by metabolite signaling. Strikingly, the identified molecular mechanism could be disrupted by repurposing a clinical approved inhibitor, which resulted in reduced metastasis formation in mouse models. Thus, this research highlights that dissecting and targeting cancer cell aggressiveness may provide therapeutic options against metastasis formation.

Citation Format: Sarah-Maria Fendt. Metastasis aggressiveness: A function of metabolite signaling [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr PL04-03.
Abstract SY02-03: Stochastic modeling of clonal evolution in carcinogenesis
Authors: Curtius Kit
Published: April 2024

In order to develop strategies that can detect cancer earlier, we need to better understand the dynamics of cancer evolution during the human lifetime. Starting from gestation, this includes measuring both the timing of early somatic mutations that lead to clonal mosaicism as well as the growth rates of mutated clones that carry higher potential for malignant transformation. Continuous observation of this evolving clonal composition across a lifetime is not feasible, therefore mathematical models are needed to integrate data from longitudinal and cross-sectional samples and infer these dynamics. Stochastic models of clonal evolution offer such a framework and provide a means for predicting individual clone trajectories into the future. Furthermore, if measurements of evolution are to be utilized clinically for early detection and patient risk stratification, faster methods to apply these models to data are required. To this end, we derived methods using coalescent theory for single-cell DNA sequencing data that enable instantaneous estimation of the growth rate of a clone along with its confidence intervals. Our tool is available in an open source R package, cloneRate, and provides the first method for constructing valid confidence intervals of growth rates analytically without having to rely on Bayesian inference techniques and complex simulations. When applying our methods to recent datasets derived from normal and neoplastic human blood cells, we quantified increased fitness effects of multi-hit driver mutations and found that higher initial clone growth rates led to decreased time to cancer diagnosis in patients. We can also use these models to estimate other important biological parameters that are difficult to measure in vivo such as bounds for total number of hematopoietic stem cells and expansion rates in early development. Ultimately, the ability to easily and quickly parameterize clonal dynamics in individual patients will benefit future early detection efforts and screening strategies for many cancer types.

Citation Format: Kit Curtius. Stochastic modeling of clonal evolution in carcinogenesis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr SY02-03.
Abstract SY05-03: Circular extrachromosomal DNA promotes tumor heterogeneity and enhancer rewiring
Authors: Chavez Lukas
Published: April 2024

Circular extrachromosomal DNA (ecDNA) in patient tumors is an important driver of oncogenic gene expression, evolution of drug resistance and poor patient outcomes. Applying computational methods for the detection and reconstruction of ecDNA across a retrospective cohort of 481 medulloblastoma tumors from 465 patients, we identify circular ecDNA in 82 patients (18%). Patients with ecDNA-positive medulloblastoma were more than twice as likely to relapse and three times as likely to die within 5 years of diagnosis. Multimodal sequencing, imaging and CRISPR inhibition experiments in medulloblastoma models reveal intratumoral heterogeneity of ecDNA copy number per cell and frequent ‘enhancer rewiring’ events on ecDNA. This study reveals the frequency and diversity of ecDNA in medulloblastoma, stratified into molecular subgroups, and suggests copy number heterogeneity and enhancer rewiring as oncogenic features of ecDNA.

Citation Format: Lukas Chavez. Circular extrachromosomal DNA promotes tumor heterogeneity and enhancer rewiring [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr SY05-03.