bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract 6134: Exploiting the oncogenic state of colorectal cancer for therapeutic development
Authors: de Sousa e Melo Felipe 
Published: April 2023

Abstract
Over the past two decades, only incremental progresses have been made in the therapeutic management of colorectal cancer (CRC). This is in part attributed to the fact that the Wnt pathway, the oncogenic pathway that initiates the transformation of CRC and sustains tumor maintenance, has been largely undruggable. While most efforts targeting Wnt signaling have revolved around interfering with Wnt target genes that regulate cell growth, we turned our attention to a subset of genes encoding for negative regulators of the pathway. Of particular interest are the cell-surface E3 ubiquitin ligases, ring finger protein 43 (RNF43) and ZNRF3, two known negative regulators of Wnt signaling that promote the turnover of Wnt receptors Frizzled/low-density lipoprotein receptor-related proteins (FZD/LRPs) via ubiquitination-mediated degradation. Given their exposed extracellular domains (ECDs), we set out to explore whether this intrinsic cellular degradative machinery could be repurposed for an antibody-based targeted protein degradation platform. More specifically, we have devised a technology that exploits the elevated expression of ZNRF3 and RNF43 in colon cancer by generating bispecific antibodies that can tether these E3 ubiquitin ligases to a variety of cell surface receptors to promote tumor receptor degradation. Most notably, these antibody degraders are highly active in vivo and can degrade receptors in a tumor specific manner while sparing normal tissues. This platform, that we have been dubbed Proteolysis Targeting Antibodies (PROTABs) describes a strategy for the rapid development of potent, bioavailable and tissue-selective degraders of cell-surface proteins.
Citation Format: Felipe de Sousa e Melo. Exploiting the oncogenic state of colorectal cancer for therapeutic development. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6134.
Abstract 6155: Lurbinectedin exhibits combinatorial activity with BCL2/BCL2L1 inhibitors in vitro and in vivo by modulation of MCL1 expression
Authors: Vaidya Kedar S. , Gupta Aparna , Hauptschein Robert , Humphreys Robin C. 
Published: April 2023

Abstract
Lurbinectedin (Zepzelca) is a marine-derived anti-tumor agent currently approved for metastatic small cell lung cancer (SCLC). Lurbinectedin has been previously shown to exert its anti-tumor effect by binding to the minor groove of DNA and inhibition of nucleotide excision repair. In addition, lurbinectedin inhibits transcription by inducing degradation of RNA polymerase II. While these activities hint towards a general mechanism, specific molecular targets for lurbinectedin remain obscure. We demonstrate that in vitro, Lurbinectedin specifically induced downregulation of MCL1 protein, a member of the BCL2 family of pro-survival proteins, in a dose- (0-30 nM) and time-dependent manner (0-24 h) by Western analysis. Expression of other pro-survival proteins BCL2 and BCL2L1 were not affected. The downregulation of MCL1 was consistent in all nine tumor cell lines tested regardless of indication. Increased activity or expression of MCL1 is a known compensatory mechanism to offset loss of BCL2 or BCL2L1. We therefore hypothesized that lurbinectedin induced MCL1 loss, along with inhibition of the pro-survival proteins BCL2 and BCL2L1 would lead to an enhancement in cell killing. Consistent with the dominant pro-survival role of BCL2 in SCLC, the combination of lurbinectedin with a specific BCL2 inhibitor (venetoclax) in vitro induced synergistic cytotoxicity (measured by Bliss Sum analysis) in a panel of small cell lung cancer lines. In solid tumor lines other than SCLC, the combination of lurbinectedin with a specific BCL2L1 inhibitor (A-1331852) was also synergistic. Correspondingly in vivo, enhancement in the efficacy of lurbinectedin was observed in combination with venetoclax in SCLC models, while in solid tumor models other than SCLC the combination with a specific BCL2L1 inhibitor enhanced efficacy. Collectively, these data identify MCL1 as a specific lurbinectedin target and suggest that combinations that target other pro-survival proteins may represent a viable strategy to enhance the anti-tumor activity of lurbinectedin.
Citation Format: Kedar S. Vaidya, Aparna Gupta, Robert Hauptschein, Robin C. Humphreys. Lurbinectedin exhibits combinatorial activity with BCL2/BCL2L1 inhibitors in vitro and in vivo by modulation of MCL1 expression [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6155.
Abstract 6160: Targeting RNA N6-methyladenosine methyltransferase, METTL3 activates p53 and apoptosis pathways in osteosarcoma cells
Authors: Shin Seungjae , Oh Yumi , Yang Yoojin , Cho Sung-Yup 
Published: April 2023

Abstract
Osteosarcoma (OS) is a malignant tumor which is mesenchymal origin from bone stroma. The 5-year overall survival of localized OS is approximately 70%, however patients who have metastasis to other organs, mostly lung, have a poor 5-year survival rate, approximately 20%. Recently, oncogenic role of Methyltransferase-like 3 (METTL3), which is the only catalytic subunit of RNA N6-Methyladenosine methyltransferase complex, has been suggested, but its mechanism in OS is still unclear. To elucidate the roles of METTL3 in OS, we generated METTL3 knock-out U2OS osteosarcoma cell lines by CRISPR knock-out system. Knock-out of METTL3 decreased cell proliferation on U2OS cells, which was assessed by WST-1 assay and manual cell counting assay. Also, RNA-sequencing was conducted in METTL3 wild type and knock-out cell lines. Gene set enrichment analysis (GSEA) revealed that gene sets of ‘Programmed cell death’ in gene ontology (GO) category, ‘p53 pathway’ and ‘Apoptosis’ in HALLMARK gene sets, and ‘p53 signaling pathway’ and ‘Apoptosis’ in KEGG pathway were enriched in METTL3 knock-out cells. To validate the result of GSEA in our METTL3 knock-out cells, mRNA and protein levels of GADD45A and CDKN1A, which are downstream targets of p53, and BAX and BAK, which are apoptosis-related molecules induced by p53, were detected by real-time PCR and western blot, respectively, and these genes were upregulated in METTL3 knock out cell lines. Collectively, these results suggest that inhibition of METTL3 is potential therapeutic targets against OS by activating p53 and apoptosis pathways.
Citation Format: Seungjae Shin, Yumi Oh, Yoojin Yang, Sung-Yup Cho. Targeting RNA N6-methyladenosine methyltransferase, METTL3 activates p53 and apoptosis pathways in osteosarcoma cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6160.
Abstract 6174: ATX-101, a peptide drug targeting PCNA, enhances the effect of gemcitabine in liposarcoma and leiomyosarcoma
Authors: Musi Elgilda , Sheikh Tahir , Ingham Matthew , Bose Sminu , Schwartz Gary K. 
Published: April 2023

Abstract
Soft tissue sarcomas are heterogeneous mesenchymal neoplasms and account for 1% of all cancers in adults. Over 50 sarcomas subtypes have been classified and many have very limited treatment options which include surgery, chemotherapy and radiation. Two of the most common sarcomas are liposarcoma and leiomyosarcoma which are often treated with chemotherapies such as doxorubicin, dacarbazine and gemcitabine with low response rates. There is now more than ever an urgent need for new therapies for sarcoma. PCNA (Proliferating Cell Nuclear Antigen) is considered to be a key regulator of DNA and cell cycle control. In addition, it has been implicated to have roles in metabolism, cellular signaling and some immunological functions. PCNA forms complexes with proteins bearing a novel PCNA-interacting Peptide Motif called APIM (AlkB homolog 2 PCNA Interacting Motif). This binding usually occurs during stress responses such as those achieved during cancer therapy or cancer development. By preventing stress proteins from repairing or defending themselves, cancer therapies can be made more effective. We examined the in vitro effects of ATX-101, a PCNA-APIM protein interaction blocking peptide, on liposarcoma cell lines LS141, DDLS, SW872, 93T449 and 94T778 and leiomyosarcoma cell lines SK-LMS, SK-UT1 and SK-UT-1B. Cell survival, as measured by cell proliferation assays, indicated IC50s of 7.5-15µM with ATX-101. Enhanced combination effects with ATX-101 and chemotherapies such as doxorubicin, irinotecan and gemcitabine were also observed by proliferation assay. Synergism, with ATX-101 and gemcitabine, was indicated with SynergyFinder analysis. Cell cycle changes exhibited increases of S and G2 phases when treated with ATX-101 and gemcitabine. This correlated with increase of cell cycle proteins, cyclin B1 and cyclin A2. Western blot observations included increase of apoptotic marker, cleaved caspase 3, and DNA damage marker, pH2A.X. In addition, immunofluorescence assay showed increasing pH2A.X with ATX-101 and gemcitabine. In vivo studies revealed ATX-101 enhanced gemcitabine decrease of tumor volume in leiomyosarcoma cell line xenograft, SK-UT1. Tumor target inhibition by western blot showed increased pH2A.X and cleaved PARP along with decreased RAD51 API protein with combination treatment. Taken these observations and results, there is strong evidence of combining gemcitabine with ATX-101 in liposarcoma and leiomyosarcoma.
Citation Format: Elgilda Musi, Tahir Sheikh, Matthew Ingham, Sminu Bose, Gary K. Schwartz. ATX-101, a peptide drug targeting PCNA, enhances the effect of gemcitabine in liposarcoma and leiomyosarcoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6174.
Abstract 6216: Pre-ribosomal RNA mediates HR repair via the BRCA1/BARD1 complex
Authors: Wu Duo , Huang Huang , Chen Tenglong , Gai Xiaochen , Liu Song , He Hu , Shi Song , Yu Xiaochun 
Published: April 2023

Abstract
The BRCA1/BARD1 complex plays a key role in DNA double-stand break (DSB) repair in both somatic cells and germ cells. However, the underlying molecular mechanism by which this complex mediates DSB repair remains elusive. Here, we show that the recruitment of the BRCA1/BARD1 complex to the unsynapsed axis of the XY body in male germ cells is mediated by pre-rRNA. Similarly, the BRCA1/BARD1 complex associates with pre-rRNA in somatic cells, which targets the BRCA1/BARD1 complex to DSBs. The interactions between the BRCT domains of the BRCA1/BARD1 complex and pre-rRNA induces liquid-liquid phase separations, which may be the molecular basis of DSB-induced nuclear foci formation of the BRCA1/BARD1 complex. Pre-rRNA also mediates BRCA1-dependent homologous recombination (HR). Cancer-associated mutations in the BRCT domains of BRCA1 and BARD1 abolish the interaction with pre-rRNA. We developed novel RNA pol I inhibitors to suppress pre-rRNA biogenesis, which not only abolished HR repair but also sensitized tumor cells to PARP inhibitor treatment. Collectively, this study reveals that pre-rRNA is a functional partner of the BRCA1/BARD1 complex in the DSB repair. It is also a potential therapeutic target for cancer therapy.
Citation Format: Duo Wu, Huang Huang, Tenglong Chen, Xiaochen Gai, Song Liu, Hu He, Song Shi, Xiaochun Yu. Pre-ribosomal RNA mediates HR repair via the BRCA1/BARD1 complex. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6216.
Abstract 624: The role of draining lymph nodes in the post-transplant recurrence of liver cancer: Examining immune response using spatial proteomics
Authors: Hickman Peyton , Thompson Aubrey E. , Nguyen Justin 
Published: April 2023

Abstract
Hepatocellular Carcinoma (HCC) and Cholangiocarcinoma (CCA) are the predominant forms of liver cancer, with a devastating combined incidence of 40,000 cases per year in the United States. Despite many differences between the cancers, liver transplant has found great success in treating both over traditional methods. However, up to 35% of patients’ cancer still recur within five years. Given the risk and resource intensiveness of this treatment, it is critical to identify factors that influence recurrence in these cancers. Previous studies have found the micro-environments of HCC tumors tend to be immune-active while those of CCA tumors tend to be immunosuppressive. Increased immune activity at the tumor level is associated with better patient outcomes, but the role and impact of the regional immune response in liver cancer is not well understood. Liver draining lymph node tissue was collected from patients undergoing orthotopic liver transplant (OLT) for HCC, CCA, or other reasons (control). Nanostring GeoMx Digital Spatial Profiler (DSP) was used to measure immune marker levelsWe found increased immune activity in the LNs of patients with HCC compared to CCA, showing significantly higher levels of lymphocytes and immune activity markers, matching previous tumor microenvironment findings. Additionally, comparing recurrent and non-recurrent HCC or CCA samples, we see generally increased immune activity in non-recurrent lymph nodes, also identifying specific immune markers in both cancer types that correlate with cancer recurrence or non-recurrence. These also reveal patterns of activity specific to both cancer type and recurrence status. Overall, this study provides novel insights into the regional immune response in liver cancers and identifies candidate proteins to serve as predictors of recurrence in liver cancer. We suggest CD163, CD66b, CD8, and CD56 as markers to predict post-OLT HCC recurrence and CD163, CD66b, ID01, and OX40L as candidate markers to predict post-OLT CCA recurrence using LN samples. Further spatial analysis of this data may further characterize immune activity in these lymph nodes, and future studies focusing on identified differences in immune activity may reveal factors affecting liver cancer aggressiveness and recurrence.
Citation Format: Peyton Hickman, Aubrey E. Thompson, Justin Nguyen. The role of draining lymph nodes in the post-transplant recurrence of liver cancer: Examining immune response using spatial proteomics [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 624.
Abstract 6380: Ultrasensitive detection of circulating human PD-1 and PD-L1 using Single Molecule Counting (SMC) technology
Authors: Faramarzi Laila , Lie Wen-Rong , Wiese Rick , Fiske Jared 
Published: April 2023

Abstract
Immune checkpoint proteins are key regulators of the immune system and potential drug targets for cancer immunotherapy. Cancer immunotherapy targeting immune checkpoint, like programmed cell death protein-1 (PD-1) and programmed cell death ligand 1 (PD-L1) inhibitors has shown treatment efficacy for a broad spectrum of human cancers. Immune checkpoint molecules PD-1 and PD-L1 are expressed on the cell surface of immune cells and tumor cells. Recent studies have also reported these immune checkpoint proteins may undergo alternative splicing or proteolytic cleavage to produce soluble checkpoint proteins. Multiple molecular forms of soluble PD-1 (sPD-1) and PD-L1 (sPD-L1) are detectable in patient sera of multiple types of cancer, and these soluble checkpoint proteins have been reported as putative liquid biopsy biomarkers in the diagnosis and prognosis of oncological disease. Though the clinical significance of circulating soluble immune checkpoint protein profiles as predictive biomarkers has yet to be fully explored and validated, we have committed to develop better and more reliable bioassays to further this research. With that, we have developed 2 Luminex-based multiplex immunoassays for simultaneous quantitation of 48 immune checkpoint proteins, including PD-1 and PD-L1, for patient sera and tumor lysate samples. Here we report the development of 2 novel Single Molecule Counting (SMC) technology-based ultrasensitive single-plex immune checkpoint immunoassays for the detection of sPD-L1 and sPD-1 in human serum and plasma samples. Comparative studies demonstrate these SMC ultrasensitive assays possesses at least 10-100-fold higher sensitivity as compared with the Luminex-based immunoassays. Using these novel ultrasensitive assays, we have validated the detection of significant increases in sPD-L1 and sPD-1 in cancer serum samples as compared with the levels in healthy controls. We have also applied these high sensitivity assays to measure human PD-L1 and PD-1 biomarkers in other sample types including urine, tumor lysates and exosomes. In conclusion, we envision that these PD-1 and PD-L1 SMC assays may overcome a major limitation in biomarker utility and enable the ultrasensitive detection of sPD-1 and sPD-L1 in liquid biopsy and blood biomarker research.
Citation Format: Laila Faramarzi, Wen-Rong Lie, Rick Wiese, Jared Fiske. Ultrasensitive detection of circulating human PD-1 and PD-L1 using Single Molecule Counting (SMC) technology [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6380.
Abstract 6389: Differential role of CD8 cells and CD4 cells in anti-tumor immunity triggered by tumor cell apoptosis using HSVtk/GCV system
Authors: Umegaki Sho , Shirota Hidekazu , Iwasaki Tomoyuki , Kasahara Yuki , Ishioka Chikashi 
Published: April 2023

Abstract
Immune cells can recognize tumor antigens and elicit an adaptive immune response, potentially resulting in tumor regression. Drug-induced dead tumor cells have been reported to enhance anti-tumor immunity, but results are conflicting, possibly due to the immunosuppressive effects of the cytotoxic drugs. To investigate whether apoptotic tumor cells trigger anti-tumor immunity independent of anti-cancer treatment, local immune responses were evaluated after direct induction of tumor cell apoptosis using a herpes simplex virus thymidine kinase (HSV-tk)/ganciclovir (GCV) system. The inflammatory cytokines IFNγ and IL-12β and anti-inflammatory factor PD-1 and TGFβ1 were upregulated at the tumor site after apoptosis induction. HSV-tk/GCV-induced tumor cell apoptosis resulted in suppression of tumor growth in vivo and promoted the infiltration of CD8 and CD4 T lymphocytes in tumor. To explore the role of T cells after induction of tumor cell death, GCV was administered together with anti-CD8 or anti-CD4 depleting antibodies to syngeneic HSV-tk transfected tumor-bearing mice. CD8 T cell depletion abrogated the anti-tumor efficacy of GCV, indicating that tumor regression was mainly dependent on CD8 T cells. This anti-tumor immunity was enhanced by anti-PD-1 antibody injection. On the contrary, CD4 T cell depletion further inhibited tumor growth than GCV alone, suggesting the potential role of CD4 T cells in suppressive tumor immunity. To elucidate this immunological mechanism, tumor tissues were evaluated after tumor cell apoptosis and CD4 T cell depletion. Foxp3, a regulatory T cell marker, was decreased after CD4 T cell depletion. In addition, Arg1, a marker of immunosuppressive myeloid cells, was significantly downregulated, which was expressed on tumor-associated macrophages (TAMs) and monocytic myeloid-derived suppressor cells (mMDSCs). Collectively, these findings indicate that tumor cell apoptosis accelerates CD8 T cell-dependent anti-tumor immunity and CD4 T cell-mediated Arg1 production from TAMs and mMDSCs.
Citation Format: Sho Umegaki, Hidekazu Shirota, Tomoyuki Iwasaki, Yuki Kasahara, Chikashi Ishioka. Differential role of CD8 cells and CD4 cells in anti-tumor immunity triggered by tumor cell apoptosis using HSVtk/GCV system [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6389.
Abstract 6398: Targeting ENPP1 to boost anti-tumor immunity during PARP inhibition
Authors: Li Jie , Mason Charlotte , Hanggi Kay , Luca Vincent , Ruffell Brian 
Published: April 2023

Abstract
Homologous recombination (HR) deficiency confers sensitivity to poly (ADP-ribose) polymerase inhibitors (PARPi), which have been approved for use in ovarian and triple negative breast cancers (TNBC) carrying loss-of-function mutations in HR pathway genes, most commonly BRCA1/2. Preclinical studies in BRCA1-deficient tumor models have demonstrated that the immune compartment is required for PARPi efficacy through the ability of PARPi to cause micronuclei formation and activate cGAS in tumors cells. The production of the 2’3’-cGAMP secondary intermediate stimulates STING in neighboring tumor-infiltrating immune cells to promote an anti-tumor response. Despite this evidence of immune stimulation, PARPi does not extend overall survival in TNBC patients, suggesting that immune suppression remains a significant barrier for efficacy. Here we sought to evaluate the role of ectonucleotide pyrophosphatase/phosphodiesterase 1(ENPP1), a type II transmembrane glycoprotein that hydrolyzes extracellular 2’3’-cGAMP. We generated Brca1/Pten/Trp53-deficient TNBC cell lines from a genetically engineered mouse model and found that these expressed higher levels of ENPP1 than Brca1-proficient TNBC and non-TNBC cell lines. Knocking out Enpp1 via CRISPR/Cas9 increased 2’3’-cGAMP production during Niraparib treatment but did not affect cellular proliferation in vitro. Critically, knocking out Enpp1 significantly reduced the growth of orthotopic Brca1-deficient tumors, with no change in growth observed for orthotopic E0771 or PyMT models, suggesting an important role for ENPP1 in HR-deficient tumors. Therapeutic dosing of Niraparib further reduced the growth of Enpp1 knockout tumors in a manner that was dependent upon host STING and correlated with higher CD8+ T cell infiltration and effector function. These findings demonstrate that ENPP1 suppresses anti-tumor immunity in Brca1-deficient tumors, suggesting that blocking the enzymatic activity of ENPP1 may provide therapeutic benefits during PARPi treatment for TNBC patients.
Citation Format: Jie Li, Charlotte Mason, Kay Hanggi, Vincent Luca, Brian Ruffell. Targeting ENPP1 to boost anti-tumor immunity during PARP inhibition. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6398.