bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 1716: A small molecule corrector for p53 mutants found in cancer
Authors: Fallatah Maryam Mohammed J , Demir Özlem , Amaro Rommie , Kaiser Peter
Published: June 2023

p53 is the main tumor suppressor protein in vertebrates and the most frequently mutated gene in human cancers. The majority of p53 mutations are missense mutations resulting in the expression of full-length p53 with inactive tumor suppressor function. Small molecule corrector drugs that change the mutant p53 conformation to a wild-type-like structure are attractive goals for personalized, targeted cancer therapies. Our previous work has shown that restoring p53 activities represses cancer cells and tumor growth in vitro and in vivo. This and other work suggest that reactivation of p53 could have therapeutic potential for cancer patients with mutated p53. This study aims to investigate a new potential p53 corrector small molecule, UCI-1001. Our data suggest that treatment of p53 mutant cancer cell lines with compounds of the UCI-1001 series inhibits cell growth in a p53 mutant-dependent manner and induces some p53-wild-type like activities such as mutant p53 DNA binding, transcriptional activation of p53 target genes, and induction of cell death. Utilizing the cellular thermal shift assay, CETSA, we show that UCI-1001 binds mutant p53 in vivo and changes mutant p53 conformation to a wild-type-like structure. Taken together, these preliminary results suggest the UCI-1001 series is a promising candidate for the development of p53 corrector drugs, but further development of pharmacokinetic properties will be necessary for translation to the bedside.

Citation Format: Maryam Mohammed J Fallatah, Özlem Demir, Rommie Amaro, Peter Kaiser. A small molecule corrector for p53 mutants found in cancer [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 1716.
Abstract 2112: Reporting recommendations for translational cancer genomic studies
Authors: Casolino Raffaella , Beer Philip A. , Normanno Nicola , Sondka Zbyslaw , Biankin Andrew V.
Published: June 2023

Background. Inaccuracy and widespread deficiencies in the reporting of translational cancer genomic studies is common and represents a major issue of cancer research. It challenges not only the study interpretation but also the ability to accurately compare studies. The REMARK (REporting recommendations for tumour MARKer prognostic studies) guideline was previously developed to improve the reporting of tumour biomarker prognostic studies. However, it presents several limitations as many aspects of omic-based research are missing. We developed a new guideline to ensure transparency and standardized reporting of clinical cancer genomic studies.

Methods. The concept for this checklist was generated after extensive review of current literature which identified major gaps in study reporting, including: insufficient information about study design, population included, and treatments; inappropriate analysis methods; and widespread deficiencies in the reporting of results. Key elements to be addressed in the new checklist were identified by experts in methodology, biostatistics, and preclinical, translational, and clinical cancer genomics (proposing panel). Several reporting guidelines produced for other types of medical research studies were also reviewed.

Results. A preliminary draft of the proposed checklist was discussed during the 18th workshop of the International Cancer Genome Consortium (ICGC) in Verona, Italy (13-14 June 2022). Building on that work, the checklist was then re-discussed and improved by the proposing panel. This will serve as a starting point for further discussion among the ICGC, REMARK, the Catalogue Of Somatic Mutations In Cancer (COSMIC), the International Quality Network for Pathology (IQN Path) and other organizations to collect any criticisms, make further revisions, and reach final consensus.

Conclusions. The proposed guideline provides a comprehensive overview to educate on good reporting of translational cancer genomic studies. It represents a valuable reference to consider when designing, conducting, and reporting this kinds of studies. After ICGC, REMARK, COSMIC, and IQN Path discussion, revision, and approval, the proposed checklist will be the new standard to be adopted by researchers, editors and reviewers. It will significantly impact future cancer research and patient care.

Citation Format: Raffaella Casolino, Philip A. Beer, Nicola Normanno, Zbyslaw Sondka, Andrew V. Biankin. Reporting recommendations for translational cancer genomic studies [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 2112.
Abstract 2216: Construction of a prognostic 6-gene signature for breast cancer based on multi-omics data
Authors: Xing Zeyu , Hong Yuting
Published: June 2023

Breast cancer (BC) is a heterogeneous disease. Distinguishing BC patients with different prognosis can help to make clinical strategies. In our study, we tried to identify novel prognostic genetic biomarkers for BC by using multi-omics data and establish a risk score (RS) signature with genetic biomarkers which have high predictive value. A combined significance (pcombined) of each gene was calculated by Fisher’s method based on the p value of the difference examination of the respective index in RNA-seq, CNV, and DNA methylation data of corresponding genes from TCGA-BRCA dataset. Genes with a pcombined < 0.010 were subjected to univariate cox and Lasso regression to screen out hub genes, whereby a RS signature consisted of six genes, C15orf52, C1orf228, CEL, FUZ, PAK6, and SIRPG, was established. With the Kaplan-Meier (KM) method, the receiver operating characteristic curves (ROC), multivariate cox regression, Nomogram, and decision curve analysis (DCA), the predicted performance of the RS signature was assessed in TCGA-BRCA, GSE7390, and GSE20685. The predicted performance in TNBC patients was emphatically analyzed in TCGA-BRCA and GSE103091, while immune characteristics were also explored. Basing on the data from Genomics of Drug Sensitivity in Cancer (GDSC) database and related R package, we further examined the drug sensitivity of TNBC patients with different RS. With survival rates having significant differences in all KM analyses and most area under ROCs reaching 0.700, the RS signature could distinguish the prognosis of patients, even stratified by disease stages or subtypes. The RS also showed a stronger predictive ability than traditional clinical indicators, including age, tumor topology (T), regional lymph node (N), metastasis (M), and TNM stage. The down-regulated expressions of many immune checkpoints were observed in TNBC patients with higher RS, while the sensitivity of many antitumor drugs was reduced in those with higher RS, except for BI2536 (CAS No.: 755038-02-9), which demonstrated a smaller half maximal inhibitory concentration (which mean a higher drug sensitivity) in TNBC patients with higher RS. In conclusion, the six genes RS signature established based on multi-omics data exhibited well performance in predicting the prognosis of BC patients, regardless of disease stages or subtypes. Contributing to a more personalized treatment, the RS signature might benefit the outcome of BC patients.

Citation Format: Zeyu Xing, Yuting Hong. Construction of a prognostic 6-gene signature for breast cancer based on multi-omics data [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 2216.
Abstract 2910: NKG2A suppression enhances the function of primary human Natural Killer cells
Authors: Croom-Perez Tayler J. , Robles-Carrillo Liza D. , Hasan Md Faqrul , Copik Alicja J.
Published: June 2023

In this study we propose inhibition of NKG2A signaling enhances the anti-tumor response of primary human NK cells. One mechanism employed by tumor cells to evade immunosurveillance is through induction of the surface expression of unconventional HLA ligands that agonize inhibitory receptors on immune cells. Specifically on some tumors, HLA-E is either expressed or its expression is known to be induced by IFNγ and is indicative of resistance to immunotherapy. HLA-E agonizes the CD94/NKG2A inhibitory complex on NK cells and some T cells to lessen their cytotoxicity, potentially decreasing the efficacy of cellular therapy with these immune cells. In this study ex vivo-expanded primary human NK cells were shown to have significantly elevated expression of NKG2A. These expanded NK cells also secreted high levels of IFNγ and could induce expression of HLA-E on tumor cells. Suppression of NKG2A by either antibody blockade or gene deletion increased the cytotoxicity of NK cells against the lung cancer cell line A549 stably expressing HLA-E. NKG2A knockout cells had an almost 10-fold decrease in EC50 compared to wild-type NK cells (EC50 0.15 vs 0.94 at 48 h), meaning nearly log-fold fewer NKG2A knockout cells are needed to kill the same number of tumor cells. The effect of NKG2A knockout on cytotoxicity of NK cells against other cancer cell lines stably expressing HLA-E will be presented along with effects of NKG2A suppression on NK cell phenotype, cytokine secretion and degranulation. These initial data suggest that blockade of the CD94/NKG2A inhibitory complex can improve the function of ex vivo expanded human NK cells and could provide an effector population with the potential for enhanced therapeutic efficacy.

Citation Format: Tayler J. Croom-Perez, Liza D. Robles-Carrillo, Md Faqrul Hasan, Alicja J. Copik. NKG2A suppression enhances the function of primary human Natural Killer 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 2910.
Abstract 292: Effects of aqueous cinnamon extract on activity of SIRT1
Authors: Hrivnak William , Prak Khanneth , Speck Cecilia , Smith Courtney , Stockert Amy
Published: June 2023

SIRT1 has drawn attention recently due to its involvement in metabolism, aging, and cancer. SIRT1 is a deacetylase enzyme that has the ability to deacetylate histones as well as other non-histone targets including p53. Studies have shown that SIRT can act either as a tumor suppressor or tumor promoter depending on the cancer and its targets in signaling pathways. Recombinant SIRT1 was used to examine the effects of cinnamon extract on SIRT1 activity using the Epigenase(™) Universal SIRT activity/Inhibition Assay Kit. Here we demonstrate that under conditions of acidic extraction, cinnamon extract functions as an activator of SIRT1 activity. Under conditions of non-acidic extraction, SIRT1 activity was relatively unchanged and slightly reduced. Studies have suggested that polyphenolic compounds, like those found in cinnamon, may epigenetically affect MCF7 cells. Therefore our future work includes plans to determine if cinnamon extracted under acidic conditions alters the expression level of SIRT1. SIRT1 activity will also be examined following cinnamon extract pretreatment.

Citation Format: William Hrivnak, Khanneth Prak, Cecilia Speck, Courtney Smith, Amy Stockert. Effects of aqueous cinnamon extract on activity of SIRT1 [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 292.
Abstract 3091: Discovery and development of a potent and highly selective WEE1 inhibitor IMP7068
Authors: Cai Sui Xiong , Ma Ning , Wang Xiaozhu , Jiang Yangzhen , Zhang Hongxia , Guo Mingchuan , Zhou Ruiyu , Tian Ye Edward
Published: June 2023

WEE1 is activated upon DNA damage and regulates the G2/M cell cycle checkpoints. Inhibition of WEE1, in conjunction with genetic alterations and/or a DNA damaging agent, could result in mitotic catastrophe and apoptosis of cancer cells, offering an attractive approach to treat cancer. Small molecule WEE1 inhibitors, such as AZD1775, showed good clinical POC (proof of concept) data in several tumors including ovarian, colon, and uterine carcinoma. We have identified a novel, potent, and highly selective WEE1 inhibitor IMP7068. Herein we will present its discovery and IND enabling in vitro and in vivo studies. IMP7068 exhibits superior WEE1/PLK1 selectivity (>435 fold) compared to AZD1775. IMP7068 also shows potent cytotoxicity against a wide range of cancer cell lines. In addition, IMP7068 has desirable PK profiles with long half-life and high exposure in preclinical species. Anti-tumor efficacy of IMP7068 has been demonstrated in mice CDX models of colorectal LoVo, non-small cell lung cancer NCI-H1299 and a PDX model of uterine UT5318 with good dose-response tumor inhibition and tolerability. IMP7068 is currently in a phase I study to evaluate its safety, tolerability, pharmacokinetics, and anti-tumor activity in patients with advanced solid tumors (ClinicalTrials.gov Identifier: NCT04768868).

Citation Format: Sui Xiong Cai, Ning Ma, Xiaozhu Wang, Yangzhen Jiang, Hongxia Zhang, Mingchuan Guo, Ruiyu Zhou, Ye Edward Tian. Discovery and development of a potent and highly selective WEE1 inhibitor IMP7068 [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 3091.
Abstract 3096: Development of pyrrolopyrimidine-based ACK1 inhibitors for cancer therapeutics
Authors: Matar Angelie , Marusyk Yuliya , Ranatunga Sujeewa , Rowsell Tegan , Amin Narmin , Walker Hannah , Tran Timothy , Yang Kathy , Duckett Derek , Reuther Gary , Lawrence Harshani , Lawrence Nicholas
Published: June 2023

Activated CDC42-associated tyrosine kinase 1 (ACK1) is an enzyme encoded by the TNK2 gene. Studies have shown ACK1 phosphorylates proteins in oncogenic pathways active in lung, leukemia, ovarian, breast, and prostate cancers. Some of these phosphorylated proteins include tyrosine-kinase B (AKT), androgen receptor (AR), tumor suppressor WWdomain oxidoreductase (WWOX), proto-oncogene tyrosine-protein kinase (FYN), and growth factor receptor bound protein 2 (Grb2). ACK1 plays a pivotal role in leukemia, breast, and prostate cancer making it an attractive anticancer drug target. The development of novel ACK1 inhibitors using a pyrrolopyrimidine scaffold is described using molecular modeling and structure-activity relationships (SAR) studies. The synthesis of a focused library using a fragment-based design strategy will be highlighted as well as progress to optimize these compounds for potency, selectivity, and cell permeability. To gain structural insights for the development of novel, potent and selective ACK1 inhibitors, we have obtained X-ray structures of our compounds bound to human ACK1. We will describe the use of molecular docking to predict the binding mode of our compounds using both reported and our new ACK1 co-crystal structures. The key residues in the ATP binding pocket of ACK1 that are exploited for inhibitor design and kinase selectivity and synthetic routes to promising compounds will be discussed. We will present the KDs of the most potent compounds derived using a differential scanning fluorimetry (DSF) thermal shift assay and cellular activities in UKE1 leukemia and MB-231 breast cancer cell lines. We will present preliminary assessment of drug-like properties, used to optimize the inhibitor class for selection of a candidate for mouse studies. Overall, our work will highlight identification/optimization of novel ACK1 inhibitors via a fragment-based approach using pyrrolopyrimidine scaffolds and their potential use as anticancer agents. We will present the synthesis, SAR analysis, and the binding mode of these inhibitors.

Citation Format: Angelie Matar, Yuliya Marusyk, Sujeewa Ranatunga, Tegan Rowsell, Narmin Amin, Hannah Walker, Timothy Tran, Kathy Yang, Derek Duckett, Gary Reuther, Harshani Lawrence, Nicholas Lawrence. Development of pyrrolopyrimidine-based ACK1 inhibitors for cancer therapeutics [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 3096.
Abstract 3521: CCND2 promotes proliferation in Drosha and DICER1 driven tumors
Authors: Fraire Claudette R. , Obalapuram Uma , Tiburcio Patricia D. , Desai Kavita , Chen Kenneth S.
Published: June 2023

Mutations in microRNA processing genes such as DROSHA and DICER1 consist of 1.5-2% of pediatric cancers including a brain tumor called pineoblastoma. We developed a genetically engineered mouse model of Drosha- and Dicer1- driven pineal tumors. These tumors develop without microRNAs and express early pineal developmental markers. Gene set enrichment analysis revealed E2F target genes to be highly expressed in these tumors. One of the most upregulated genes in these tumors is cyclin D2 (Ccnd2). Additionally, these tumors stain positively for Rb phosphorylation. In a Wilms tumor cell line (WiT49) with Drosha knocked down, RNA sequencing revealed that CCND2 was the most upregulated gene. Similarly, in patient-derived xenografts (PDXs) of DICER1-related tumors such as pleuropulmonary blastoma (PPB), we observed high expression of CCND2 and positive staining for Rb phosphorylation. To test the dependence of Rb phosphorylation in Drosha and Dicer tumors, we next treated a Drosha pineal tumor allograft with a CDK4/6 inhibitor, palbociclib, and observed tumor growth suppression. Additionally, treatment of DICER1 mutant PPB PDXs with palbociclib had similar results. These experiments suggest that CDK4/6 is important for tumor proliferation in Drosha and DICER1 driven cancers.

Citation Format: Claudette R. Fraire, Uma Obalapuram, Patricia D. Tiburcio, Kavita Desai, Kenneth S. Chen. CCND2 promotes proliferation in Drosha and DICER1 driven tumors. [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 3521.
Abstract 3597: SUV420H2-mediated regulation of collective invasion in triple-negative breast cancer
Authors: Whitt Emily Campbell , McLane Laura M. , Vertino Paula M.
Published: June 2023

Breast cancer is the second most common cancer in women and metastasis is the leading cause of breast cancer-related mortality. While the factors leading to metastasis remain poorly understood, epigenetic changes in the cancer cell are likely strongly associated with the shift from primary tumor to metastasis. There are several breast cancer subtypes, the most aggressive of which is triple-negative breast cancer which is difficult to treat in part because it is prone to metastasis. In the early stages of metastasis, cells from the primary tumor invade the surrounding tissue before breaking away and seeding metastases. In some cases, tumor cells invade as clusters of cells that migrate as a group and maintain their cell-cell contacts through a process known as collective invasion. These clusters of collectively invading cells have been shown to seed circulating tumor cell clusters that are more efficient at forming metastases than single tumor cells. SUV420H2 is a histone methyltransferase that trimethylates histone H4 lysine 20 (H4K20me3), an epigenetic mark associated with transcriptional repression. Triple-negative breast cancer has lower levels of SUV420H2 and H4K20me3 levels than more luminal subtypes. Our lab and others have found that downregulation or inhibition of SUV420H2 promotes increased plasticity in the epithelial-to-mesenchymal transition, a transcriptional program associated with cancer metastasis. Our objective was to use a three-dimensional tumor spheroid system to determine the role of SUV420H2 and H4K20me3 on breast cancer invasion. We found that in immortalized non-tumorigenic breast cells grown as spheroids in an extracellular matrix, knockdown of SUV420H2 promotes invasion. Treatment of triple-negative breast cancer spheroids with an inhibitor of SUV420H2 (A196) also leads to an increase in invasion, as well as a shift in invasive phenotype from one where cells invade as single cells to a one where cells invade as collective chains emanating from the central spheroid. This suggests that reduced levels of SUV420H2 and the associated changes in histone marks and transcriptional programming in triple-negative breast cancer promote a phenotypic shift from single cell to collective invasion and may be one factor contributing to the increased metastatic potential of this subtype. Future studies will focus on characterizing the effects of SUV420H2 loss on gene and protein expression as well as chromatin in invading cells in tumor spheroids.

Citation Format: Emily Campbell Whitt, Laura M. McLane, Paula M. Vertino. SUV420H2-mediated regulation of collective invasion in triple-negative breast cancer. [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 3597.
Abstract 3616: Investigating proto-oncogene PBF-induced cell migration and invasion
Authors: Kocbiyik Merve , Manivannan Selvambigai , Zha Ling , Brookes Katie , Read Martin L , McCabe Chris J , Smith Vicki E
Published: June 2023

The proto-oncogene pituitary tumor transforming gene binding factor (PTTG1IP/PBF) is overexpressed in multiple tumors and associated with tumor progression. PBF mediates several tumorigenic processes, including cell motility, whereby it potently induces cancer cell migration and invasion. PBF is phosphorylated by Src kinase at Y174 and mutation of this residue (Y174A) renders PBF unable to induce cell invasion, suggesting that phosphorylation mediates the stimulation of cancer cell motility by PBF. This study aimed to further elucidate the mechanism of PBF-induced cell motility. PBF-Y174 is also the key residue in a YXXΦ endocytosis motif. Both PBF phosphorylation and endocytosis were found to be essential for PBF-induced cell motility as mutants which disrupted either process were unable to stimulate thyroid and breast cancer cell migration and invasion. To elucidate molecular events downstream of PBF overexpression, phosphoproteomic and RNA-Seq analyses of normal thyroid cells (Nthy-ori 3-1) with stable PBF overexpression were performed and showed an enrichment in molecules involved in cell adhesion and cytoskeleton organisation. These findings prompted further investigation into a physiological role for PBF in cell motility. We utilised a novel Pbf knockout (Pbf−/−) mouse model generated through CRISPR/Cas9-mediated deletion of Pbf exon 4 in C57BL/6N mice to determine the impact of Pbf deletion on cellular mechanisms. Mouse embryonic fibroblasts (MEFs) were isolated at embryonic day 13.5 and used as primary cultures. Pbf−/- MEFs showed a significant reduction in migration and invasion compared with wild-type (Pbf+/+) MEFs. Interestingly, the loss of one functional copy of Pbf in heterozygote MEFs (Pbf+/−) resulted in an intermediate decrease in motility suggesting a gene-dosage effect. Initial immunofluorescent studies of Pbf−/− MEFs suggest alterations in focal adhesions (FAs). In Pbf+/+ MEFs focal adhesion kinase (FAK) and paxillin staining highlighted FA structures that were normally elongated and aligned with actin stress fibers. In contrast, Pbf−/- MEFs demonstrated a significant reduction in FAK and paxillin staining with smaller, punctate and more radially distributed FAs. These studies demonstrate a physiological role for PBF in cell adhesion and migration and further elucidate the mechanism by which PBF induces cell motility in tumor progression.

Citation Format: Merve Kocbiyik, Selvambigai Manivannan, Ling Zha, Katie Brookes, Martin L Read, Chris J McCabe, Vicki E Smith. Investigating proto-oncogene PBF-induced cell migration and invasion. [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 3616.
Abstract 3634: Overexpression of PLK1 activates IL4/JAK/STAT6 signaling in prostatic tumor-microenvironment
Authors: Wang Ruixin , Liu Xiaoqi
Published: June 2023

The correlation between PLK1 expressions with prostate cancer (PCa) stages was identified by analyzing the transcriptome profile of PLK1 in patients from the Cancer Genome Atlas (TCGA) database, and scoring the protein expression in a clinical tissue microarray (TMA) cohort. Integrating our prostate-specific PLK1 knock-in mouse model, we established an oncogenic role for PLK1 in PCa progression. To elucidate the underlying mechanism, we investigated the impact of PLK1 overexpression on prostatic tumor microenvironment (TME) in vivo. In addition, in vitro co-culture systems with both epithelial cells and macrophages were designed to uncover the regulatory function of PLK1 in macrophage polarization. We found that PLK1 induces phosphorylation of JAK3, activates the JAK/STAT6 pathway in cancer cells, and increases the secretion of IL4, which enables macrophage polarization towards the M2 phenotype in TME—ultimately accelerating PCa development. Finally, pharmaceutical inhibition of STAT6 signaling significantly reverses the PLK1-mediated M2 polarization and, subsequently, inhibits the progression of PCa. Our findings provide clinical and pre-clinical evidence to characterize the role of PLK1 in promoting PCa and novel insights into the regulatory mechanism of PLK1 in the TME. We also provide strong support for the clinical potential of targeting STAT6 for advanced PCa therapy.

Citation Format: Ruixin Wang, Xiaoqi Liu. Overexpression of PLK1 activates IL4/JAK/STAT6 signaling in prostatic tumor-microenvironment. [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 3634.
Abstract 3731: The polyamine-hypusine circuit controls an oncogenic translational program essential for malignant transformation in MYC-driven lymphoma
Authors: Nakanishi Shima , Li Jiannong , Berglund Anders E. , Kim Youngchul , Zhang Yonghong , Zhang Ling , Yang Chunying , Mirmira Raghavendra G. , Cleveland John L.
Published: June 2023

The MYC oncoprotein is activated in a broad spectrum of human malignancies and transcriptionally reprograms the genome to drive cancer cell growth. Given these functions, it is unclear if targeting a single effector of MYC will have therapeutic benefit. MYC activates the polyamine-hypusine circuit, which post-translationally modifies a single lysine residue (Lys-50) of eukaryotic translation initiation factor eIF5A in a process coined hypusination via two enzymes,deoxyhypusine synthase (DHPS) and deoxyhypusine hydroxylase (DOHH). The roles of this circuit in cancer are unclear. Here we report essential intrinsic roles for hypusinated eIF5A in the development and maintenance of MYC-driven lymphoma, where loss of eIF5A hypusination completely abolishes malignant transformation of MYC-overexpressing B cells in transgenic mice predestined to develop lymphoma. Mechanistically, integrating RNA-seq, Ribo-seq and proteomic analyses revealed that efficient translation of select targets is dependent upon eIF5A hypusination, including regulators of G1-to-S phase cell cycle progression and DNA replication. Thus, this circuit controls MYC’s proliferative response at several levels and is activated in many tumor types. These findings suggest the hypusine circuit as a therapeutic target for a broad spectrum of malignancies.

Citation Format: Shima Nakanishi, Jiannong Li, Anders E. Berglund, Youngchul Kim, Yonghong Zhang, Ling Zhang, Chunying Yang, Raghavendra G. Mirmira, John L. Cleveland. The polyamine-hypusine circuit controls an oncogenic translational program essential for malignant transformation in MYC-driven lymphoma. [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 3731.
Abstract 3808: MicroRNA-206 drives antitumor immunity by disrupting the communication between Kupffer cells and Tregs
Authors: Song Guisheng , Liu Ningning
Published: June 2023

Kupffer cells (KCs) account for 15% of the total liver cells. However, their roles in hepatocellular carcinoma (HCC) is poorly described. Clec4fCre-tdTomato knock-in mice expressing Cre recombinase and tdTomato-NLS under the KC-specific Clec4f promoter were hydrodynamically injected with oncogenic AKT and Nras (AKT/Ras) to induce HCC. A LoxP-stop-LoxP (LSL) system was used to express miR-206 in KCs of mice. AKT activation was observed in hepatocytes and KCs of HCC patients. Hydrodynamic injection (HDI) of AKT/Ras led to activation of AKT signaling in KCs and hepatocytes. AKT/Ras mice developed lethal HCC within 6-8 weeks post injection. Activation of AKT signaling led to M2 polarization of KCs, increased hepatic Tregs and exhaustion of CTLs. MicroRNA (miR) profiling revealed that AKT/Ras impaired miR-206 biogenesis in KCs by driving translation of Yin Yang 1 (YY1), a transcription repressor of miR-206. HDI of miR-206 into AKT/Ras mice fully prevented HCC, while all control mice died of HCC 6-8 weeks post injection. However, HDI of miR-206 only transfected ~ 20% of hepatocytes, indicating that it is unreasonable to conclude that the full prevention of HCC in AKT/Ras/miR-206 mice is caused by inhibited proliferation of HCC cells. We, therefore, posited that miR-206-mediated recovery of immune surveillance, at least in part, accounted for the full prevention of HCC in AKT/Ras/miR-206 mice. We next used the LSL system to overexpress miR-206 in KCs of Clec4fCretdTomato mice injected with AKT/Ras. KC-specific expression of miR-206 fully prevented HCC in AKT/Ras mice, while 100% control mice died of HCC. Mechanistically, AKT signaling in KCs drove CCL22 (C-C motif chemokine ligand 22) production by phosphorylating β-catenin that activates transcription of Ccl22. In contrast, miR-206 disrupted β-catenin signaling by targeting LEF1 (lymphoid enhancer-binding factor 1), an “architectural” transcription factor of β-catenin. CCL22 recruits Tregs. Indeed, KC-specific expression of miR-206 led to elevated CCL22, M2 to M1 transition of KCs, reduced hepatic Tregs, and elevated CTLs. Depletion of CTLs in AKT/Ras mice fully offset the ability of miR-206 to prevent HCC.

Conclusions: AKT-educated KCs initiate Treg recruitment via a regulatory loop consisting of YY1, β-catenin/LEF1, miR-206, and CCL22; once this loop is activated, AKT activates β-catenin axis, which drives CCL22 production, Treg recruitment and HCC growth; while KC-specific expression of miR-206 reversed this process by blocking β-catenin axis in KCs. miR-206 represents a novel immunotherapy against HCC.

Citation Format: Guisheng Song, Ningning Liu. MicroRNA-206 drives antitumor immunity by disrupting the communication between Kupffer cells and Tregs. [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 3808.
Abstract 4009: Discovery of PLM-102, a highly potent 3rd generation FLT3 inhibitor, in drug-resistant FLT3-ITD-TKD mutated acute myeloid leukemia
Authors: Park Jin-Hee , Lee Jae-Seon , Oh Su-jin , Lee So-Deok , Choi Yong June , Kang Keon Wook , Moon Miran , Jang Soo Yeon , Kim Myung Jin , Kim Yong-Chul
Published: June 2023

Mutations of the FMS-like tyrosine kinase 3 (FLT3) gene occur in approximately 25 ~ 30% of all acute myeloid leukemia (AML) cases and FLT3-ITD mutations are associated with a particularly unfavorable prognosis, with an increased risk of relapse and shorter overall survival (OS) compared with AML patients without the mutation. Even though multiple FLT3 inhibitors are in various stages of clinical evaluation, resistance to FLT3 inhibitors resulting from acquired point mutations in tyrosine kinase domain (TKD) have limited the sustained efficacy of treatments. Among them, a “gatekeeper” mutation (F691L) is resistant to most available FLT3 inhibitors. Here, we show the efficacy and mechanism of PLM-102, developed an orally available and highly selective small molecule, in overcoming drug-resistant FLT3-ITD-TKD mutations as a strong candidate of the 3rd generation of FLT3 inhibitor.

PLM-102 displays extraordinary potency of enzyme inhibitory activities of all FLT3 WT/mutants including F691L with IC50 values of <1 nM. In FLT3-ITD-positive cell lines (MV4-11, MOLM-13, MOLM-14, Ba/F3-ITD-D835Y, Ba/F3-ITD-F691L), PLM-102 shows about 18~25-fold higher anti-proliferative activities than Gilteritinib. Also, PLM-102 potently inhibited the phosphorylation of FLT3 and its downstream signaling pathways, and induced apoptosis as evidenced by PARP-cleavage and caspase-3 activation.

Moreover, in AML-related xenograft mouse models (MV4-11, MOLM-14, Ba/F3-ITD-D835Y, Ba/F3-ITD-F691L), once-daily oral dose of PLM-102 significantly suppressed the tumor growth and achieved complete tumor regression. In addition, the outstanding efficacy of our compound has been confirmed in large tumor xenograft models. These results are very encouraging because large tumors have a limited blood supply and high interstitial fluid pressure, leading to a poor absorption of anticancer drugs. Pharmacokinetics of PLM-102 displayed higher bone-marrow exposure indicating better target engagement and benefits in the clinical translation in AML.

In conclusion, PLM-102 is a promising therapeutic candidate for the FLT3-ITD-mutated AML as well as the acquired resistance to current FLT3 inhibitors.

Citation Format: Jin-Hee Park, Jae-Seon Lee, Su-jin Oh, So-Deok Lee, Yong June Choi, Keon Wook Kang, Miran Moon, Soo Yeon Jang, Myung Jin Kim, Yong-Chul Kim. Discovery of PLM-102, a highly potent 3rd generation FLT3 inhibitor, in drug-resistant FLT3-ITD-TKD mutated acute myeloid leukemia. [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 4009.
Abstract 4130: Genetically modified hematopoietic stem cells for improvement of immunotherapies against solid malignancies
Authors: Font Laura Falceto , Jin Dan , Francis Connor P. , Dean Bayli DiVita , Figg John W. , McDonald Brianna , Flores Catherine
Published: June 2023

Hematopoietic stem cells (HSCs) are routinely used in the clinic to treat several diseases and their side effects, including cancers. Our group has previously shown that the combination of HSCs with two different immunotherapies improves survival in brain tumors, but it is still not curative. In this study, we wanted to explore whether modifying HSCs can drive them into a dendritic cell phenotype or suppress them from becoming immunosuppressive myeloid cells at the tumor microenvironment to increase survival when combined with immunotherapy in a glioma model. HSCs have been historically challenging to grow in vitro for long-term culture due to the short periods of time they remain undifferentiated, which creates an extra challenge for the genetic modification of HSCs. Here, we test different in vitro conditions for expansion and modification of murine and human HSCs by employing the following methods for modulation of HSCs: shRNA lentiviral delivery, overexpression constructs, RNA electroporation, CRISPR, and AAV. This study describes the efficacy of each method as well as the observed limitations of each technique on HSCs. Furthermore, preliminary data shows IL6R downregulation as a candidate for driving HSCs into the dendritic cell lineage. Ultimately, these genetically modified cells will be used as an adjuvant therapy to improve the efficacy of various immunotherapeutic strategies against solid malignancies.

Citation Format: Laura Falceto Font, Dan Jin, Connor P. Francis, Bayli DiVita Dean, John W. Figg, Brianna McDonald, Catherine Flores. Genetically modified hematopoietic stem cells for improvement of immunotherapies against solid malignancies. [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 4130.
Abstract 4131: Long-term anti-tumor immunity induced by of HPN328, a DLL3-targeting trispecific, half-life extended T cell engager, in a preclinical immunocompetent mouse model
Authors: Molloy Mary Ellen , Valenzuela Laura B. , Wu Chi-Heng , Wesche Holger , Anand Banmeet S.
Published: June 2023

Tri-specific T Cell-Activating Constructs (TriTACs) are T-cell engagers that have been developed to redirect T cells to kill tumor cells. HPN328 is a Delta-like ligand 3 (DLL3)-targeting TriTAC currently being evaluated in a Phase 1/2 clinical trial enrolling patients with advanced cancers associated with DLL3 expression, including small cell lung cancer (SCLC) and other neuroendocrine malignancies (NCT04471727). HPN328 consists of three binding domains: a CD3 binder for T cell engagement, an albumin binder for half-life extension, and a DLL3 binder for tumor cell engagement. We have previously reported that HPN328 induces potent dose-dependent killing of DLL3 expressing SCLC cell lines together with dose-dependent T cell activation and cytokine release in T cell co-cultures in vitro. Based on these data and the proposed mechanism of TriTAC induced tumor cell killing we hypothesized that HPN328 could induce epitope spreading and long-term immunogenic effects. To test this hypothesis, we generated an immunocompetent mouse model in which six amino acid residues corresponding to the portion of human CD3ε which TriTAC molecules bind were added to the N terminus of the mouse CD3ε subunit. Homozygous knock-in mice (hCD3ε) were implanted subcutaneously with MC38 murine colon cancer cell line expressing human DLL3 and treated with HPN328 following tumor establishment. HPN328 treatment led to eradication of established tumors in mice. In addition, tumor infiltrating lymphocyte (TIL) analysis was performed on tumors harvested on day 4 post HPN328 treatment. Activation markers CD69 and CD25 were induced on both CD4+ and CD8+ TILs in this model. To evaluate if HPN328 can induce long-term immunity, mice whose tumors were cured by HPN328 were rechallenged on the opposite flank. As expected, tumors grew in treatment naïve mice, but no tumors were detected in mice previously treated with HPN328, demonstrating sustained and durable anti-tumor immunity induced by HPN328 treatment. Anti-tumor immunity is an indicator of T cell memory against tumor antigens. Concomitant with anti-tumor immune response, we detected increases in memory T cells in the spleens of mice previously treated with HPN328. Together these results indicate that HPN328 can induce epitope spreading and prolonged anti-tumor immunity, suggest a novel mechanism for its activity and efficacy in vivo.

Citation Format: Mary Ellen Molloy, Laura B. Valenzuela, Chi-Heng Wu, Holger Wesche, Banmeet S. Anand. Long-term anti-tumor immunity induced by of HPN328, a DLL3-targeting trispecific, half-life extended T cell engager, in a preclinical immunocompetent mouse model. [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 4131.
Abstract 4405: Tumor mutational burden, as a potential predictive marker for the efficacy of immunotherapy in advanced gastric cancer
Authors: Jang Jaeyeon , Jeon Youngkyung , Jeong Sun Young , Jung Ye Ji , Choi Daeho , Hong Joohyun , Lee Jeeyun , Kang Won Ki , Kim Seung Tae
Published: June 2023

Background: The optimal value of tumor mutational burden (TMB) for predicting treatment response of immunotherapy in advanced gastric cancer (AGC) is still unclear. We aimed to establish the optimal cut-off value of TMB, and evaluate the efficacy of immunotherapy in AGC according to TMB and other markers.

Method: From October 1, 2020, to July 27, 2021, at Samsung medical center in Korea, patients with AGC, who received pembrolizumab or nivolumab were included. TMB was measured by next-generation sequencing (NGS)-based assays, and PD-L1 is tested using immune-histochemical assay 22C3 pharmDx. Based on receiver operating characteristic analysis, the cut-point value of TMB was determined as the point where the Youden’s index is maximum.

Result: A total of 53 patients were analyzed. The cut-off value of TMB for predicting the overall response of immune checkpoint inhibitors was defined as 13.31 mutations/megabase (mt/mb), with 56% of sensitivity and 95% of specificity. Under this definition of TMB, 7 patients were TMB-high group (≥13.31 mt/mb), while 46 patients were TMB-low group (<13.31 mt/mb). The overall response rate (ORR) had a statistically significant difference between TMB-low (8.7%, n=4/46) and TMB-high patients (71.4%, n=5/7; p=0.001). The progression-free survival (PFS) and overall survival (OS) for 53 patients were 1.93 months (95% CI, 1.600-2.268) and 4.26 months (95% CI, 2.992-5.532). The OS was longer in the TMB-high group with the median of 20.8 months (95% CI, 2.292-39.281) compared to the TMB-low group with the median of 3.31 months (95% CI, 1.604-5.019; p=0.049). The ORR of the patients whose PD-L1 CPS was 1 or above was not different from the patients whose PD-L1 CPS was lower than 1.

Conclusion: In this study, the optimal value of TMB for predicting the objective response rate of immunotherapy in AGC was determined as 13.31 mt/mb. TMB-high (≥13.31 mt/mb) was associated with a better objective response rate, and TMB-high patients exhibited better overall survival. TMB has the potential for predicting therapeutic response to immunotherapy in advanced gastric cancer.

Citation Format: Jaeyeon Jang, Youngkyung Jeon, Sun Young Jeong, Ye Ji Jung, Daeho Choi, Joohyun Hong, Jeeyun Lee, Won Ki Kang, Seung Tae Kim. Tumor mutational burden, as a potential predictive marker for the efficacy of immunotherapy in advanced gastric cancer. [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 4405.
Abstract 4585: Tumor lymphangiogenesis sensitizes melanomas to the immunological effects of radiotherapy but also disrupts the local lymphatic vasculature
Authors: Mukherjee Anish , Mitrousis Nikolaos , Sasso Mari Stella , MacDonald Margo , Arina Ainhoa , Ang Phillip , Baginski Ariana , Medellin J. Emiliano G. , Weichselbaum Ralph R. , Swartz Melody A.
Published: June 2023

Tumor lymphangiogenesis is typically associated with cancer progression and metastasis. However, recent studies from our group have demonstrated that tumor lymphangiogenesis promotes intratumor T cell infiltration and potentiates the efficacy of a wide range of immunotherapies in melanoma-bearing mice as well as patients undergoing checkpoint blockade. Radiotherapy (RT) can also induce immunogenic tumor cell death, so we investigated whether lymphangiogenic tumors would yield more immunogenic responses to RT than non-lymphangiogenic tumors. Here, we compared effects of RT in mice bearing B16-F10 melanomas expressing either a control vector (B16-Ctrl) or overexpression the lymphangiogenic factor VEGF-C (B16-VC), where lymphatic vessels were significantly increased in number and size compared to B16-Ctrl tumors. First, we find that B16-VC regress faster than B16-CT after RT (either a single 20 Gy dose or two 15 Gy doses), and that this regression was correlated with enhanced CD8+ T cell activity. On the other hand, lymphatic endothelial cells (LECs) can be more sensitive to damage from RT if they are undergoing lymphangiogenesis. We found that irradiated B16-VC tumors showed higher levels of intra-lymphatic fibrin. Consistent with this, LECs in the irradiated B16-VC tumors expressed higher levels of tissue factor and caspase-3, which correlated with the degree of lymphatic clotting. Fibrin clotting was also observed in the subcapsular sinus of the draining lymph nodes of irradiated B16-VC tumors. These findings highlight the complex role of tumor lymphangiogenesis in radiotherapy responses, where they may potentiate acute anti-tumor immune responses but may also cause localized damage of the vasculature, potentially leading to increased metastasis. Further studies are needed to investigate therapeutic targets to inhibit lymphatic coagulation and look at its effects on cancer immunotherapy and metastasis.

Citation Format: Anish Mukherjee, Nikolaos Mitrousis, Mari Stella Sasso, Margo MacDonald, Ainhoa Arina, Phillip Ang, Ariana Baginski, J. Emiliano G. Medellin, Ralph R. Weichselbaum, Melody A. Swartz. Tumor lymphangiogenesis sensitizes melanomas to the immunological effects of radiotherapy but also disrupts the local lymphatic vasculature. [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 4585.
Abstract 4656: Targeting macrophage PI3KGamma in aggressive prostate cancer
Authors: Adusei Kenneth M. , Nirschl Thomas R. , Lee Alex J.-E. , Shen Fan , Wang Xiaoxu , Alvarez Jade , Lotan Tamara L. , Varner Judith , Zarif Jelani
Published: June 2023

The phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K) family of lipid kinases play key roles in cancer biology by promoting cell motility, growth, and survival. Of the four class I PI3K isoforms, PI3Kα,β,δ,γ, the PI3Kγ isoform is primarily expressed by myeloid cells. Studies from the Varner lab have established that the macrophage lipid kinase, PI3Kγ, selectively promotes myeloid cell trafficking and immune suppressive transcription in tumor associated monocytes and macrophages, thereby inhibiting T cell recruitment, activation, and tumor eradication. We hypothesized that antagonism or deletion of PI3Kγ would induce tumor growth inhibition in vivo in prostate cancer (PCa) models. To test our hypothesis, we implanted syngeneic murine prostate cancer tumors (B6CaP) into global PI3Kγ knock out mice and preliminary studies show severe tumor growth inhibition. Using a publicly available single cell RNA sequencing database of metastatic PCa (mPCa) tumors from bone, we calculated regulon scores for transcription factors C/EBPβ and NFκB which are up and down-regulated by PI3Kγ signaling in myeloid cells respectively. This analysis indicated that a notable proportion of monocytes in mPCa have active PI3Kγ signaling based on C/EBPβ activity and a lack of NFκB activity. Finally, we tested the significance of eganelisib treatment on monocytes and found that this pathway was essential for monocyte survival during macrophage differentiation and adhesion. Altogether, our proposed research delineates the mechanistic roles of PI3Kγ in the regulation of prostate cancer tumor growth and support PI3Kγ as a target to sensitize PCa to immune checkpoint inhibitors.

Citation Format: Kenneth M. Adusei, Thomas R. Nirschl, Alex J.-E. Lee, Fan Shen, Xiaoxu Wang, Jade Alvarez, Tamara L. Lotan, Judith Varner, Jelani Zarif. Targeting macrophage PI3KGamma in aggressive prostate cancer. [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 4656.