bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract 844: Germline TP53 missense mutations at codon338 confer adult-onset cancer risk through weakened p53 protein oligomeric stability that impairs its tumor suppressive mechanisms
Authors: Fischer Nicholas W. , Turk Jaime , Ong Noel , Duan Shili , Kaustov Lilia , Kratz Christian , Pajtler Kristian , Kim Raymond , Arrowsmith Cheryl , Malkin David 
Published: June 2022

Abstract
Pathogenic TP53 germline variants predispose carriers to a high lifelong cancer risk in Li-Fraumeni syndrome (LFS). LFS presents as a broad phenotypic spectrum with highly variable age-of-onset and tumor types. The mechanisms leading to these phenotypic differences remain largely unknown, and many less frequent variants are not clinically defined as pathogenic or benign. Two missense mutations in the tetramerization domain of the p53 protein, F338S and F338C, have recently been of clinical interest; however, they are currently classified as variants of uncertain significance. Normally, p53 assembles as a tetrameric complex to bind DNA and transcriptionally regulate the expression of target genes involved in the cellular response to stress, acting as a crucial barrier to malignant transformation. Alterations to p53 structure can therefore lead to malfunction and ultimately tumor formation. Our structural analysis of the tetramerization domain demonstrates that F338S and F338C have significantly lower thermal stability compared to the wildtype protein. Furthermore, our functional assessments of apoptosis and the suppression of colony formation indicate that both variants operate with reduced tumor suppressor activity, although they maintain near wildtype functionality. We anticipate that our results will help to better understand why these mutations cause a history of predominantly adult-onset cancers in the affected families and could justify refining surveillance measures for these individuals.
Citation Format: Nicholas W. Fischer, Jaime Turk, Noel Ong, Shili Duan, Lilia Kaustov, Christian Kratz, Kristian Pajtler, Raymond Kim, Cheryl Arrowsmith, David Malkin. Germline TP53 missense mutations at codon338 confer adult-onset cancer risk through weakened p53 protein oligomeric stability that impairs its tumor suppressive mechanisms [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 844.
Abstract 847: Role of RHOA in diffuse gastric cancer tumors
Authors: Martinez-Barriocanal Agueda , Dopeso Higinio , Jiménez-Flores Lizbeth M. , Santos Juliana C. , Anguita Estefania , Bilic Josipa , Nieto Rocio , García-Vidal Elia , Martín Manuel Sánchez , Landolfi Stefania , Kobayashi Kazuto , Hernandez-Losa Javier , Schwartz Simo , Cajal Santiago Ramón y , Arango Diego 
Published: June 2022

Abstract
Gastric cancer constitutes the third leading cause of cancer mortality worldwide and tumors with diffuse histology have poor prognosis and low response rates to therapy. Missense mutations in the RHOA (Ras homolog family member A) GTPase have recently been identified in 24% of patients with diffuse gastric cancer. RHOA mutations are not randomly distributed along the coding sequence, but enriched in specific and recurrent hotspots. Substitution in codon 42 (Y42C) occurs in approximately 50% of the patients in which RHOA is mutated. RHOA orchestrates cellular processes such as proliferation, differentiation, migration and invasion, whose deregulation is essential for the onset, maintenance and progression of tumors. However, the functional role of wild type RHOA and RHOA mutants remains poorly characterized in gastric cancer. We used isogenic cell lines systems and animal models to study the impact of RHOA in the gastric tumorigenesis. RHOA loss strongly increased the proliferation, migration and invasion of diffuse gastric cancer cells in vitro, but also when growing as subcutaneous xenografts in immunodeficient mice, and in experimental mouse models of peritoneal and lung metastasis. Stomach tumor burden was also increased in transgenic mice conditionally expressing a dominant negative form of RHOA in the gastrointestinal tract (RHOA T19N). Moreover, cells overexpressing wild-type RHOA or G14V RHOA (a constitutive active form of the GTPase) exhibited reduced tumorigenic features both in vitro and in vivo. Conversely, diffuse gastric cancer cells engineered for overexpressing RHOA Y42C mutant, displayed enhanced growth and invasion in vitro. Importantly, stomach cancer tumors formed more efficiently in a transgenic mouse model in which we targeted the expression of Y42C RHOA mutant to the gastric epithelium. Collectively, these results demonstrate that RHOA has tumor-suppressive activity in diffuse gastric cancer, while the recurrent Y42C hotspot RHOA mutation found in these tumors is oncogenic.
Citation Format: Agueda Martinez-Barriocanal, Higinio Dopeso, Lizbeth M. Jiménez-Flores, Juliana C. Santos, Estefania Anguita, Josipa Bilic, Rocio Nieto, Elia García-Vidal, Manuel Sánchez Martín, Stefania Landolfi, Kazuto Kobayashi, Javier Hernandez-Losa, Simo Schwartz, Santiago Ramón y Cajal, Diego Arango. Role of RHOA in diffuse gastric cancer tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 847.
Abstract 848: Inhibition of RTK fusion condensates enhances signal perception and promotes drug tolerance
Authors: Gonzalez-Martinez David , Roth Lee , Mumford Thomas , Mosse Yael , Tulpule Asmin , Bivona Trever , Bugaj Lukasz Jan 
Published: June 2022

Abstract
Drug resistance remains a significant obstacle in the successful treatment of cancer, highlighting the critical need to understand how oncogenes and cancer drugs impact cell physiology and resistance development. EML4-ALK is a receptor tyrosine kinase (RTK) fusion oncogene that drives 3-7% of lung cancer. Despite potent ALK inhibitors, EML4-ALK+ cancers frequently develop resistance during therapy. Recently, it was discovered that EML4-ALK and other RTK fusions form cytoplasmic protein condensates, and that condensate formation was required for oncogenic signaling. However, whether oncogenic condensates play a role in drug responses is unclear. In this study, we applied an optogenetic technique called ‘functional profiling’ to understand how EML4-ALK condensates impact cell signal transmission and drug response. Using light-stimulated RTKs, we found that EML4-ALK condensates strongly suppress signaling through transmembrane RTKs, including through EGFR, a central receptor in resistance development. Strikingly, treatment with ALK inhibitors (ALKi) rapidly restored and hypersensitized RTK signaling. We found that EML4-ALK condensates suppress RTK signals through sequestration of the downstream adapter Grb2, which is essential for signaling through EGFR and other RTKs. The release of Grb2 from condensates resensitized RTKs within 10s of minutes of ALKi addition. Resensitized RTKs, in turn, caused sporadic RTK activation pulses throughout the cell population, and pulses originated from paracrine RTK signals released by apoptotic neighbors. We found that these paracrine signals counteracted ALK inhibitor therapy and promoted survival and drug tolerance. Blocking paracrine signals through co-treatment of ALKi with inhibitors of either EGFR or matrix metalloproteases enhanced cell killing and minimized long-term drug tolerance. Our study uncovers a role for oncogenic condensates in drug resistance signaling, reveals a novel mechanism for oncogene-induced suppression of RTK signaling, and suggests novel co-therapies to more effectively treat cancers driven by EML4-ALK and possibly other RTK fusions. Our work also demonstrates the potential of functional optogenetic profiling for drug discovery to promote cancer therapy.
Citation Format: David Gonzalez-Martinez, Lee Roth, Thomas Mumford, Yael Mosse, Asmin Tulpule, Trever Bivona, Lukasz Jan Bugaj. Inhibition of RTK fusion condensates enhances signal perception and promotes drug tolerance [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 848.
Abstract 855: Analysis of canonical uveal melanoma mutations reveals novel signaling effects
Authors: Owens Dawn Alexandra , Kurtenbach Stefan , Kuznetsoff Jeffim N. , Rodriguez Daniel A. , Cruz Anthony , Harbour J. 
Published: June 2022

Abstract
Uveal Melanoma (UM) is the most common primary ocular cancer in adults. Virtually all UM have activating mutations in the Gq signaling pathway. Metastatic risk in patients correlates with additional secondary mutations, where the lowest metastatic risk (class 1) is associated with EIF1AX and SF3B1, and the highest metastatic risk (class 2) is associated with BAP1 mutations. The interplay between the initiating Gq pathway mutations, and the secondary mutations found in all UM has not been well understood yet. Here, we utilize a multi-omics approach, to describe gene expression changes, the proteome, and phosphatome, following GNAQ mutation and BAP1 knockout in primary human uveal melanocytes. We generated human uveal melanocyte cell lines with inducible and specific mutations and analyzed via RNAseq, ATACseq, and mass spectrometry. Results reveal significant changes in pathways related to p53, chromatin regulation/modification, gene expression, and RNA processing with noted dysregulation of genes JUN, HDAC4, YAP, and SOX10, which cause senescence in melanocytes following GNAQ mutation, and are relieved through additional mutation in BAP1.
Citation Format: Dawn Alexandra Owens, Stefan Kurtenbach, Jeffim N. Kuznetsoff, Daniel A. Rodriguez, Anthony Cruz, J. Harbour. Analysis of canonical uveal melanoma mutations reveals novel signaling effects [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 855.
Abstract 860: Identifying mechanisms associated with slow proliferation of BAP1 mutant uveal melanoma cells
Authors: Chua Vivian , Baqai Usman , Purwin Timothy J. , Jeon Angela , Han Anna , Aplin Andrew 
Published: June 2022

Abstract
Uveal melanoma (UM) is the deadliest form of eye cancer in adults. Primary tumors in the uveal tract are often treated successfully by enucleation or radiotherapy but 50% of cases develop metastases which occur primarily in the liver. Patients diagnosed with metastatic UM usually have a poor prognosis with a short median survival of 5-18 months due to the lack of effective treatment options. Metastatic UM responds poorly to many therapeutic options. Inactivating mutations in BRCA1-associated protein 1 (BAP1), a tumor suppressor gene and de-ubiquitinating (DUB) enzyme, have been reported in &gt;80% metastasizing UM and thus are associated with elevated risks of UM metastasis. However, the role of BAP1 in UM metastasis is unclear. Interestingly, silencing of BAP1 in UM cell lines was shown to inhibit UM cell proliferation and cell cycle progression. Consistent with this finding, we show that BAP1-deficient or BAP1 mutant UM cells proliferated slower than BAP1 wild-type (WT) cell lines. Re-expression of BAP1 in a BAP1-deficient or mutant UM cell line, MP65, also increased the proliferation rate of cells. Analysis of reverse phase protein array (RPPA) identified that phosphorylation of the S6 ribosomal protein is elevated in BAP1 proficient cells. Re-expression of BAP1 WT also increased phosphorylation of S6 and its upstream regulator, p70S6K1. Additionally, BAP1 mutant UM cells were more viable compared to isogenic cells expressing BAP1 WT in response to amino acid deprivation. These findings suggest that loss of BAP1 is associated with better survival under environmental stress, a critical step during metastasis. Positivity for pS6 was detected in all metastatic UM specimen tested regardless of BAP1 status. This suggests a role of the tumor microenvironment in regulating pS6 levels in UM cells at the metastatic site. Our findings show BAP1-dependent regulation of UM cell proliferation and response to stress, and uncover S6 and its associated pathway as an opportunity for therapeutic target in BAP1 mutant UM.
Citation Format: Vivian Chua, Usman Baqai, Timothy J. Purwin, Angela Jeon, Anna Han, Andrew Aplin. Identifying mechanisms associated with slow proliferation of BAP1 mutant uveal melanoma cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 860.
Abstract 867: Velcrin-induced cleavage of tRNA-Leu-TAA by SLFN12 RNase causes cancer cell death
Authors: Lee Sooncheol , Hoyt Stephanie , Wu Xiaoyun , Garvie Colin , McGaunn Joseph , Cherniack Andrew D. , Meyerson Matthew , Greulich Heidi 
Published: June 2022

Abstract
Velcrins are small molecules that induce apoptosis of cancer cells expressing high levels of phosphodiesterase 3A (PDE3A) and schlafen family member 12 (SLFN12) by inducing PDE3A-SLFN12 complex formation. Recently, we found that SLFN12 is an RNase and PDE3A binding dramatically activates SLFN12 RNase activity, resulting in velcrin-mediated apoptosis. However, the mechanism of cancer cell death by the PDE3A-SLFN12 complex is poorly understood. In this study, we found that SLFN12 specifically recognizes tRNA-Leu-TAA and induces its cleavage in velcrin-sensitive cell lines. According to tRNA-sequencing, tRNA-Leu-TAA isodecoders decreases by 2-fold to 5-fold in Hela cells treated with DNMDP compared to DMSO control, while other tRNAs are not differentially expressed. Down-regulation of tRNA-Leu-TAA by velcrin treatment is observed only in velcrin-sensitive cell lines but not insensitive cell lines. Furthermore, we tested whether SLFN12 digests tRNA-Leu-TAA in vitro. Purified wild-type SLFN12 cleaves tRNA-Leu-TAA but not heat-denatured or catalytically inactive SLFN12. Even though tRNA-Leu-TAA is weakly digested by low concentrations of SLFN12, co-incubation with purified PDE3A increases SLFN12 RNase activity, which is even further upregulated by velcrin treatment. To verify specificity for tRNA-Leu-TAA, we assessed activity of SLFN12 against a panel of in vitro transcribed tRNAs. We found that purified SLFN12 is significantly more efficient at degrading tRNA-Leu-TAA when compared with tRNA-Leu-TAG or tRNAs for other amino acids. Digestion of tRNA-leu-TAA by SLFN12 could inhibit mRNA translation due to the delivery of leucine amino acid to elongating ribosomes. To test this hypothesis, we designed the mutant tRNA-Leu-[CAG:TAA] in which the anticodon of tRNA-Leu-CAG was replaced by TAA anticodon. Ectopic expression of wild-type tRNA-Leu-TAA or tRNA-Leu-CAG has no effect on viability of DNMDP-treated cells, whereas expression of tRNA-Leu-[CAG:TAA] genes partially rescues the cells from DNMDP-induced cytotoxicity. These data confirm that impaired leucine delivery is responsible at least in part for the observed effects of DNMDP treatment.
Citation Format: Sooncheol Lee, Stephanie Hoyt, Xiaoyun Wu, Colin Garvie, Joseph McGaunn, Andrew D. Cherniack, Matthew Meyerson, Heidi Greulich. Velcrin-induced cleavage of tRNA-Leu-TAA by SLFN12 RNase causes cancer cell death [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 867.
Abstract 882: A novel p73 C-terminal isoform, p73α1, regulates inflammation and tumor suppression via the Notch1 pathway
Authors: Laubach Kyra , Yan Wenshen , Kong Xiangmudong , Chen Mingyi , Zhang Jin , Chen Xinbin 
Published: June 2022

Abstract
p73, a member of the p53 family, is expressed as two N-terminal isoforms: TA, a tumor suppressor and ΔN, an oncoprotein. Alternative RNA splicing at the 3` end gives rise to multiple C-terminal isoforms, but their function is largely unknown. To address this, CRISPR was used to knock out exon 12 (E12) in several cell lines and mice, leading to isoform switching from p73α to p73α1. p73α1 is a novel isoform whose expression we detected in multiple cancer cell lines. We found that knockout of E12 inhibits the cell proliferation and migration abilities of H1299 and MIA PaCa-2 cancer cells and E12-/- MEFs exhibit increased cellular senescence. Similarly, ectopic expression of p73α1 in H1299 cells suppresses cell proliferation and knockdown of p73α1 restores the cell proliferative and migratory capacities of H1299 E12-/- cells. Consistently, we found that E12+/- mice are not prone to spontaneous tumors, unlike Trp73+/- mice, but instead are prone to chronic systemic inflammation and show elevated IL-1β and IL-6 expression in inflamed tissues. We then identified Notch1, a master regulator of the inflammatory response, as a mediator of p73α1-induced inflammation and tumor suppression, and found it to be elevated in inflamed E12+/- mouse tissues. Furthermore, we found that knockdown of Notch1 enhances cell proliferation and migration in H1299 E12-/- cells. Together, these data suggest that p73α1 plays a role in the inflammatory response and tumor suppression via Notch1.
Citation Format: Kyra Laubach, Wenshen Yan, Xiangmudong Kong, Mingyi Chen, Jin Zhang, Xinbin Chen. A novel p73 C-terminal isoform, p73α1, regulates inflammation and tumor suppression via the Notch1 pathway [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 882.
Abstract 883: Defining the observed mutual exclusivity between SF3B1 and TP53 mutations in cancer
Authors: Bergman Riley , Park Ben , Croessmann Sarah 
Published: June 2022

Abstract
SF3B1 is the most commonly mutated splicing factor in cancer, occurring in a broad variety of hematologic and solid malignancies, including: breast, melanoma, pancreatic, bladder, colorectal, leukemia, and more. SF3B1 is a protein component of the spliceosome responsible for recognizing intronic splice sites and stabilizing the interaction between the spliceosome and pre-mRNA transcripts. Hotspot mutations in SF3B1 result in a neomorphic protein that causes aberrant splicing of hundreds of transcripts. These transcriptional alterations have several proposed impacts on known cancer pathways; however, the mechanisms by which SF3B1 mutations contribute to tumorigenesis are incompletely understood. Interestingly, systematic analysis of online cancer databases shows SF3B1 mutations and TP53 alterations are mutually exclusive in cancers with predominant SF3B1 hotspots, suggesting either synthetic lethality or overlapping roles in promoting tumorigenesis. To address this question, TP53 was knocked-out using CRISPR-Cas9 in AAV-generated SF3B1 K700E mutant knock-in and wild type MCF-10A breast epithelial cells. Successful generation of TP53 knock-outs in both the SF3B1 mutant and wild type groups suggests the mutations are unlikely to be synthetic lethal. Instead, this finding may direct us to novel mechanisms by which SF3B1 mutations contribute to cancer development and progression. Two overarching areas of interest based on preliminary data include changes in mitochondrial metabolism and metabolic reprogramming and alterations in DNA damage, repair, and genomic stability. Further defining the relationship between mutant SF3B1 and TP53 may reveal new mechanisms of tumorigenesis and reveal therapeutic vulnerabilities that can be additionally leveraged against the large subset of cancers with TP53 mutations.
Citation Format: Riley Bergman, Ben Park, Sarah Croessmann. Defining the observed mutual exclusivity between SF3B1 and TP53 mutations in cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 883.
Abstract 888: Elucidating the mechanisms of eATP-induced changes in cell growth, energy metabolism, and cancer stem cells in human non-small lung cancer A549 cells
Authors: Song Jingwen , Chen Xiaozhuo 
Published: June 2022

Abstract
The tumor microenvironment (TME) has concentrations of extracellular ATP (eATP) 103-104 times higher than normal healthy tissues, implying that eATP may have important roles in tumor development and progression. Our previous study, cited by a Nature Reviews Cancer paper, showed that the extracellular ATP (eATP) is internalized by tumors via macropinocytosis, a type of endocytosis, to increase intracellular ATP (iATP) levels and support tumor cells growth, drug resistance, and cancer cell movement by initiating epithelial to mesenchymal transition (EMT). Recently, our lab found that eATP functions in promoting cancer cell growth, metastasis are similar to those of TGF-β, a well-known EMT and cancer stem cells (CSCs) inducer. Increasing reports state that the EMT and CSCs share some molecular links, but the detailed mechanisms and inductor of them are still far from clear. In this report, eATP’s function in CSCs induction was investigated first. Result shows that eATP treatment significantly induces the protein expression level of CSC related makers, increases cell colony numbers, and cell populations with CSC markers expressed in human lung cancer A549 cells. In addition, RNA-sequencing analysis reveals the gene Stanniocalcin 1 (STC1) is significantly upregulated in both eATP and TGF-β treatments. STC1 gene has been reported to be a competitive biomarker in the tracking of cancers’ progressing. Besides, STC1 exhibits concentration-dependent stimulation effects on electron transportation chain (ETC) and respiration. However, the detail function of STC1 gene in eATP induced cell growth is unknown. To find out the mechanism, CRISPR-Cas9 technique was used to generate STC1 gene targeted knockout (STC1 KO) A549 cells. STC1 KO cells show slower cell growth rate, lower intracellular ATP level and lower oxygen consumption rate (OCR) when compared with normal A549 cells in vitro. These results strongly indicate STC1 gene involved in eATP induced cell growth by alteration iATP level and metabolic profile. Overall, this study not only unravels new role of eATP in CSC induction, but also provides new mechanism of eATP induced cell growth by altering the protein expression level of STC1.
Citation Format: Jingwen Song, Xiaozhuo Chen. Elucidating the mechanisms of eATP-induced changes in cell growth, energy metabolism, and cancer stem cells in human non-small lung cancer A549 cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 888.