tbuckley/cabot-search huggingface dataset:
Abstract 5638: The BAF complex mediates intertwined activity of YAP1 and β-catenin in synovial sarcoma
Authors: Ilka Isfort, Ruth Berthold, Lorena Heinst, Anna Kuntze, Eva Wardelmann, Marcel Trautmann, Wolfgang Hartmann
Journal: Cancer Research (2024)

Abstract Introduction: Synovial sarcoma (SySa) is a rare malignant soft tissue tumor characterized by a specific reciprocal translocation t(X;18). The resulting chimeric SS18::SSX fusion protein drives SySa tumorigenesis by integrating into BAF chromatin remodeling complexes, changing their composition and dysregulating gene transcription. The role of BAF complexes in cancer steadily increases with ∼20% of all malignancies having alterations in BAF complex subunits. BAF complexes are multiprotein complexes with several interaction partners determining their localization and functionality. Since previous analyses revealed an induced activation of the transcriptional coregulators YAP1 and β-catenin in SySa, the aim of this study was to analyze if nuclear YAP1 and β-catenin are interacting with BAF complexes and if this has an impact on their transcriptional activity. Experimental procedures: Co-immunoprecipitation experiments on nuclear protein extracts and proximity ligation assays were performed to investigate interactions between YAP1, β-catenin, and BAF complex subunits in SySa cells. Knockdown of common and specific BAF complex subunits was conducted employing RNA interference. To assess changes in YAP1 and β-catenin transcriptional activities, TEAD and TOPFlash luciferase reporter assays were performed, respectively, and protein expression levels were detected by immunoblotting. Results: In SySa, protein-protein interaction experiments revealed nuclear interactions between β-catenin, YAP1, the SS18::SSX fusion protein and various BAF subunits. YAP1 and β-catenin’s transcriptional activities were found to be interdependent as they mutually enhanced each other’s activation. Knockdown of SS18::SSX as well as specific BAF complex subunits was associated with diminished transcriptional activities of these coregulators and, interestingly, substantially affected their mutual activation. This indicates that SS18::SSX-containing BAF complex assembly is crucial for interdependent YAP1 and β-catenin activation in SySa cells. Conclusions: This study reveals a significant role of the SySa-specific fusion protein and BAF chromatin remodeling complexes in mediating intertwined activation of YAP1 and β-catenin. Citation Format: Ilka Isfort, Ruth Berthold, Lorena Heinst, Anna Kuntze, Eva Wardelmann, Marcel Trautmann, Wolfgang Hartmann. The BAF complex mediates intertwined activity of YAP1 and β-catenin in synovial sarcoma [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 5638.
Abstract 6985: The oncogenic functions and action mechanism of UTP14A, a subunit required for 18S rRNA synthesis, in head and neck cancer
Authors: Li-Wha Wu, Chen-Ni Chang, Pulak K. Biswas, Sen-Tien Tsai
Journal: Cancer Research (2024)

Abstract Head and neck cancer (HNC) is the sixth common malignancy in the world and &amp;gt; 90% of HNC cases are squamous cell carcinoma in origin. Oral cancer is one major HNC subtype. Despite the recent advancements in cancer diagnostics and therapeutics, the 5-yr survival rate of advanced HNC patients remains &amp;lt;50%. Ribosomes are the cellular factories responsible for making proteins. The hyper-activation of ribosome biogenesis initiated by oncogene gain or tumor suppressor gene loss plays a critical role in cancer initiation and progression. Ribosome biogenesis is a complex and energy intensive process that involves hundreds of factors. UTP14A gene encodes a member of the uridine triphosphate 14 family and is an essential component of a large ribonucleoprotein complex bound to the U3 small nucleolar RNA. Previous studies have demonstrated that UTP14A plays a key role in the synthesis of ribosomes and 18S rRNA, and is overexpressed in several malignancies. However, the biological functions and underlying mechanisms of UTP14A in HNC remain elusive. We found not only the increase of UTP14A mRNA expression in TCGA-HNC database but also its negative impact on patient clinical outcome. UTP14A depletion significantly impaired HNC cell proliferation, migration and invasion in vitro. Ectopic overexpression had the opposite effect, suggesting an oncogenic role for UTP14A in HNC. Through gene set enrichment analysis of pairwise RNA sequencing results, several genes involved in the process of epithelial mesenchymal transition (EMT) were potentially associated with manipulated UTP14A expression. We also detected a concordant change of lipid droplet numbers and its surface marker expression in UTP14A-manipulated cells, respectively, by BODIPY staining and immunhistochemical staining. Western blot analysis validated a positive relationship of EMT markers and COX-2, a potential mediator of lipid metabolism and EMT, with altered UTP14A expression. The involvement of COX2 in UTP14A mediation was confirmed by using both pharmacological inhibition and genetic manipulation. We also identified p38 as a central downstream effector but acting upstream from COX-2 in UTP14A mediation in oral cancer cells. We believe that our study of UTP14A-mediated oncogenic signaling axis can potentially be harnessed as a novel therapeutic target against HNC although more mechanistic studies may be needed. Citation Format: Li-Wha Wu, Chen-Ni Chang, Pulak K. Biswas, Sen-Tien Tsai. The oncogenic functions and action mechanism of UTP14A, a subunit required for 18S rRNA synthesis, in head and neck 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 6985.
Abstract 5443: Identifying key regulators of glioblastoma cancer stem cells
Authors: Tao Wang, Xuanhua Xie, Luis F. Parada
Journal: Cancer Research (2024)

Abstract Glioblastoma multiforme (GBM) has a dire prognosis that has had little progress over the past three decades. The existence of a unique population of stem-like gene signature baring quiescent cells (GSCs) within GBM are important for GBM tumorigenesis, therapy-resistance and recurrence. Our lab has developed one of the most faithful genetically engineered mouse models, encompassing a Nestin promoter-enhancer driven CreERT2-H2BeGFP-hDTR cassette (hereafter as CGD), that allows us to accurately capture and isolate GSCs in mouse GBM. The next logical step is to leverage these tools to uncover therapeutic vulnerabilities of GSCs and make a meaningful impact on GBM patient outcomes. To our knowledge, very few studies have explored the functional regulators of GSCs using a CRISPR/Cas9 screening approach. Our GSC signature provides a strong foundation for performing targeted in vitro or in vivo screens. In this study, to identify functionally important genes that may regulate GSC self-renewal and tumorigenic properties, an in vitro CRISPR knockout screens using a gene library derived from the GSC signature. The viral library was applied to low passage primary cultures of FACS sorted CGD_GFP+ and CGD_GFP- GBM cells developed from CGD; Nf1f/+;Trp53f/f;Ptenf/+ mice, respectively. The result of our in vitro CRISPR knock-out screen demonstrated guide depletion of Atp1b2-sgRNA in CGD_GFP+ but not in CGD_GFP- cells. The main objective of this study is to utilize in vitro and in vivo functional assays to test the difference between Atp1b2 WT and Atp1b2 KO GSCs and Atp1b2 WT vs KO GSC-derived tumors. Having a targeted candidate gene list is also particularly helpful for designing an in vivo CRISPR knockout screen, which is more physiological relevant. Therefore, I propose to use the candidate gene list derived from the in vitro screen as a starting point. The in vivo screen can provide valuable insights for the selection of the most optimal candidates for anti-GSC therapies. Citation Format: Tao Wang, Xuanhua Xie, Luis F. Parada. Identifying key regulators of glioblastoma cancer stem cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5443.
Abstract 5442: Terthighcells: key players in salivary gland homeostasis and regeneration after radiation therapy in adult mice
Authors: Li Guan, Vignesh Viswanathan, Sivakamasundari V, Hongbin Cao, Yuyan Jiang, Junfei Zhao, Deana R. Colburg, Patrick T. Neuhoefer, Yu Xu, Eyiwunmi E. Laseinde, Steven Artandi, Quynh-Thu Le
Journal: Cancer Research (2024)

Abstract Salivary gland homeostasis and regeneration post-radiotherapy depend significantly on stem/progenitor cells. However, the lineage of SMG progenitor cells is not as well defined as in other normal organs, and better understanding of this population would be important for their future clinical application for tissue regeneration. Using a mouse strain expressing regulated CreERT2 recombinase from the endogenous Tert locus, we identify a distinct Terthigh cell population that are located in the ductal region throughout the submandibular gland (SMG), express ASCL3 (another progenitor cell marker) and can give rise to ductal cells during homeostasis. In contrast, Terthigh cells are found to repopulate both ductal and acinar cells at one year of tracing after radiotherapy. Terthigh cells from adult SMG retain self-renewal capacity when subjected in vitro culture, are resistant to radiation cell kill, and display enhanced proliferative activity post-radiation. Similarly, primary human SMG cells with high Tert expression display enhanced cell survival after radiotherapy. RNA sequencing reveals upregulation of the cell cycling and oxidative stress response pathways these cells after radiation. Mechanistically, Tert appears to modulate cell survival and ROS level in SMG spheres following radiation damage. Collectively, these data suggest that Terthigh cells constitute a novel subset of SMG progenitor cells located throughout the ductal region of the gland that can help to repopulate both ductal and acinar cells after RT damage. Citation Format: Li Guan, Vignesh Viswanathan, Sivakamasundari V, Hongbin Cao, Yuyan Jiang, Junfei Zhao, Deana R. Colburg, Patrick T. Neuhoefer, Yu Xu, Eyiwunmi E. Laseinde, Steven Artandi, Quynh-Thu Le. Terthighcells: key players in salivary gland homeostasis and regeneration after radiation therapy in adult mice [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 5442.
Abstract 5441: Down regulation of cysteine glutamate antiporter in ALDH1A1 expressing oral and breast cancer stem cells induced oxidative stress triggered ferroptosis
Authors: Ravishankar Bellala
Journal: Cancer Research (2024)

Abstract Background: Sulfasalazine, an xCT inhibitor, is being used as a repurposed antineoplastic drug to induce ferroptosis. Ferroptosis is a regulated necrotic cell death pathway that is dependent on iron reserves. Interestingly, cancer stem cells (CSCs) that are regarded as major drivers of resistance to conventional therapies accompanied with tumor relapse and recurrence have bulk amount of iron reserves in the form of ferritin. This suggests that inducing ferroptosis might disrupt stemness and drug resistant mechanisms in cancer stem cells, thereby reducing the risk of drug resistance, cancer recurrence, and relapse. Materials &amp; Methods: In the present study, ALDH1A1 expressing oral (OCSCs) and breast (BCSCs) cancer stem cells were sorted and used to investigate the role of sulfasalazine to induce ferroptosis. To check the self-renewability of CSCs spheroid formation assay was performed and the resultant CSCs were treated with sulfasalazine (SAS) and subjected to gene expression analysis RT PCR and flow cytometry. FACS was performed to check stem cell marker expression, cell cycle arrest, and apoptosis. Results: Our results suggest that the cells showed a gradual increase in sphere formation till S3 in the case of OCSCs and S2 in the case of BCSCs, with a gradual decrease in sphere forming efficiency from the respective generations. When treated with 0.6mM SAS, these cells induced ferroptosis by downregulating stem cell markers like ALDH1A1, SLC7A11, ferritin, and GPx 4 with a concomitant increase in transferrin and STEAP 3. Flow cytometry studies revealed that the cells have undergone mitochondrial dysfunction characterized by loss of membrane potential and the cell cycle progression was halted in the G2/M phase. Conclusion: In the present study, we demonstrate that SAS potentially induced ferroptosis accompanied with oxidative stress in both OCSCs as well as BCSCs by lowering GPx 4 activity, a key enzyme that scavenges the products produced as a result of oxidative stress. Citation Format: Ravishankar Bellala. Down regulation of cysteine glutamate antiporter in ALDH1A1 expressing oral and breast cancer stem cells induced oxidative stress triggered ferroptosis [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 5441.
Abstract 544: Reverse engineering strategy for new targets identification
Authors: Bin Xie, Taimei Zhang, Le Li, Hongkui Chen, Yang Liu, Lintao Bi, Danyi Wen
Journal: Cancer Research (2024)

Abstract The issue of drug resistance in cancer is very similar to the field of infectious disease, either existing before treatment (intrinsic) or generated during therapy (acquired), highly affected by cell endogenous factors and/or the surrounding environment. Acquired resistance can be occurred several months after targeted therapy via alternations of drug targets due to the genomic mutations of the targets, epigenetic transcriptional or translational changes, for example the C797S mutation impairs AZ9291 binding to the EGFR kinase domain. To overcome this, novel well-designed chemical compounds targeting new mutations would be urgently needed, as well as the potential new oncogenes/susceptible genes driving the resistance. Considering about the heterogeneity of primary tumor tissues, LIDE has established one functional cost-effective in vitro and in vivo screening method, named reverse engineering strategy for targets identification by using patients-derived conditional reprogramed cancer cell lines (CRs) and IO-FIVE (Immuno-Oncology drugs Five In Vivo Efficacy test). Basically, pro-siRNA library or CRISPR/sgRNA library is carried out in CRs for candidates hunting, alternatively drug-response evaluation among multiple clinical biopsies in mice cancer trials, after filtered with bioinformatic scanning from large groups of patients, and finally it is validated in vivo by CRISPR, shRNA silence or targeted compounds. In addition to these known factors (EGFR C797S, Her2/Met amplification, Ras and MAPK activation), we have discovered that epigenetic factors for DNA modification, protein translation kinases, mitochondrial/peroxisomal transporters and cell membrane lectins may contribute to AZ92921 resistance in vivo. And one previously unknown acyltransferase member has been identified as key driver gene for pan-cancer development by IO-FIVE, and patients with high expression level of this enzyme have had poor survival outcomes, accompany with uncontrolled tumor growth and immunotherapy resistance, which is becoming a promising therapeutic target. Citation Format: Bin Xie, Taimei Zhang, Le Li, Hongkui Chen, Yang Liu, Lintao Bi, Danyi Wen. Reverse engineering strategy for new targets identification [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 544.
Abstract 5446: The role of snoRNAs in GBM cells, GSCs, neuronal precursor cells (NPCs), astrocytes, and normal brain tissues
Authors: Sujash Chatterjee, Scott Kuersten, Christina Middle, Morgan Roos, Pedro A. Galante, Gabriela Guardia, Luiz Penalva
Journal: Cancer Research (2024)

Abstract rRNA modification are a crucial step in ribosome assembly and function. Small nucleolar RNAs select which nucleotides in rRNAs get modified. Typically, C/D box snoRNAs are implicated in 2’-O-ribose methylation (2’Omet) while H/ACA box snoRNAs are responsible for pseudo-uridylations. Alterations in snoRNA expression have been described in multiple tumor types while distinct snoRNAs have been linked to cancer-relevant phenotypes. Our initial study on snoRNA expression using a dedicated Ampliseq platform revealed a specific glioma stem cell (GSC) signature. We propose this snoRNA signature creates a unique rRNA modification pattern that shapes the ribosome, favoring the translation of genes in pathways critical for GSC growth and survival. We will expand our study and characterize the expression profile of snoRNAs and 2’Omethylation in a large panel of GBM cells, GSCs, neuronal precursor cells (NPCs), astrocytes, and normal brain tissues. Next, we will select snoRNAs displaying differential expression in GSCs and determine if changes in their levels affect proliferation, viability, response to temozolomide and radiation, and translation. We and others have observed that the integrity of protein complexes that regulate ribosomal biogenesis depends on PolyADP-ribosylation (PARylation)and PAR-binding. In agreement, genomic screenings determined that multiple genes regulating ribosome biogenesis confer sensitivity to PARP inhibitors. These findings offer a therapeutic opportunity. We will investigate the functional impact of PARylation on rRNA modification by determining the effect of PARP inhibitors on snoRNP assembly and 2’Omethylation. Finally, we will test the hypothesis that PARP and ribosome biogenesis inhibitor combinations would be more effective than PARP inhibition alone in treating GBM. Citation Format: Sujash Chatterjee, Scott Kuersten, Christina Middle, Morgan Roos, Pedro A. Galante, Gabriela Guardia, Luiz Penalva. The role of snoRNAs in GBM cells, GSCs, neuronal precursor cells (NPCs), astrocytes, and normal brain tissues [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 5446.
Abstract 5449: Exploring signaling pathways essential for stemness and metastasis of colorectal cancer cells
Authors: Teruaki Fujishita, Makoto M. Taketo, Masahiro Aoki
Journal: Cancer Research (2024)

Abstract The prognosis of colorectal cancer (CRC) patients with distant metastasis remains poor, requiring elucidation of molecular mechanisms and identification of therapeutic targets. While cancer stem cells have been implicated in metastasis, recurrence, and drug resistance, our understanding of the regulatory mechanisms governing the stemness of CRC stem cells remains largely incomplete. In this study, we utilized an innovative autochthonous metastatic mouse model of CRCs generated by the introduction of sporadic mutations in Ctnnb1, Kras, Trp53, and Smad4 genes (CKPS mice) and CRC cell lines derived from the mice (CKPS cells). Our investigation revealed that the cAMP/PKA/CREB and TGFβ/SMAD4 pathways play a positive and negative role, respectively, in the sphere-forming and metastasis-initiating ability of CRC cells. Treatment with the CREB inhibitor 666-15 or the genetic knockout of CREB significantly reduced the spheroid-forming and metastasis-initiating potentials of CKPS cells. Intriguingly, we observed that the irinotecan treatment induced CREB phosphorylation in liver metastases, and co-treatment of 666-15 greatly potentiated the inhibitory effect of irinotecan on liver metastasis. Furthermore, we found that the transition from 2D to 3D spheroid culture of CKPS cells led to the induction of RhoC expression. Notably, RhoC knockout in CKPS cells effectively suppressed spheroid formation in vitro and inhibited metastasis formation in an intrasplenic injection liver metastasis assay. Potential therapeutic implications of these findings will be discussed. Citation Format: Teruaki Fujishita, Makoto M. Taketo, Masahiro Aoki. Exploring signaling pathways essential for stemness and metastasis of colorectal cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5449.
Abstract 1339: Pre-clinical development of IAMA-004, a tri-specific antibody targeting innate immune receptors and tumor targets
Authors: Liming Liu, Zhen Han, Yang Fan, Qi Pan
Journal: Cancer Research (2024)

Abstract Immune check-point inhibitor (ICI) such as anti-PD1 or anti-PDL1 antibody, which enhances the adaptive immunity via re-energizing exhausted T cells, has become the foundational therapy for many cancers. However, due to variety of other immunosuppressive tumor microenvironments, it is efficacious only in 15-30% of the patients. It is well known both the innate immunity and the adaptive immunity are required for full control of cancer growth. Thus, therapeutics harnessing the innate immunity will be complementary to ICI and improve the cancer response rate when used in combination. Currently therapeutics harnessing the innate immunity mainly involve bispecific antibodies with one arm targeting tumor antigen and one arm connecting to innate effector cells such as NK cells or macrophages, represented by CD30-CD16a bispecific and Her2-CD47 bispecific respectively. Considering that cancer patient’s immune status are heterogenous, varying from T cell exhaustion, macrophage disfunction (M2 bias), Treg cell presence to NK cell deficiencies, it would be advantageous to combine several innate immunity enhancers into one therapeutic molecule. Here we describe a long-acting tri-specific antibody termed IAMA-004 that targets Her2 as the primary target and CD47 and CD16a as effector cell engagers. CD47 is also a co-target on some tumor cells (CD47-Her2 double positive tumors). We have characterized this molecule both in vitro and in vivo. The in vitro experiments tested the molecule’s ability to kill Her2 high, Her2 low and Her2 negative tumor cell lines including BT-474, SK-OV-3, NCI-N87, OE19, HCC1954, MDA-MB-231, MDA-MB-468, in human PBMC ADCC assays with DS-8201 and Trastuzmab as the comparator molecules. In all of these ADCC experiments, IAMA-004 showed superior tumor cell killing activities to those mediated by DS-8201 or Trastuzmab. When combined with IAMA-005 (a Fc-IL2-IFN-α fusion cytokine), the tumor cell killing activities were dramatically increased. In addition, IAMA-004 was also tested in patient-derived Ex-Vivo fluids (one malignant pleural effusion and one malignant asities) and demonstrated tumor cell killing efficacies; and the killing activity could be attributed to the specific arms of the molecule. These results suggest that it is feasible to combine more than one innate engager in one molecule to carry out specific functions in the heterogeneous immune status for the treatment of advanced cancer patients. Citation Format: Liming Liu, Zhen Han, Yang Fan, Qi Pan. Pre-clinical development of IAMA-004, a tri-specific antibody targeting innate immune receptors and tumor targets [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 1339.