bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 5778: Determining the structure and function relationship of the oxysterol-binding protein (OSBP) to guide drug development
Authors: Bayimenye Ruth Fiona , Berrios-Rivera Jorge L. , Nimmo Susan , Bourne Christina R. , Burgett Anthony W.
Published: March 2024

The human Oxysterol Binding Protein Structure and function relationship remains elusive, yet the anti-cancer and antiviral molecules library targeting OSBP and OSBP-Related proteins (ORPs) continues to grow. OSBP is a ubiquitously expressed protein in most eukaryotes, functioning as a master lipid sensor and cholesterol regulator in cells. OSBP and its closely related protein ORP4 are also reported to be essential in several human diseases, including viral infection and cancer cell proliferation. Our lab has shown that the natural product OSW-1 has potential anti-viral and anti-cancer activity through targeting OSBP and ORP4, as confirmed with protein-ligand interactions that showed binding with high affinity. Moreover, several anti-cancer molecules targeting the ORPs provoke different protein conformation changes and, therefore, lead to varying OSBP functions. However, the structure of full-length OSBP is still unknown, which leaves a gap in knowledge regarding the compounds’ mechanism of action or how OSBP could be established as a molecular anti-cancer target. Our goal is to determine the structure and function relationship of OSBP with emphasis on the effect of small molecule ligands on cellular OSBP levels and function. In pursuit of this research goal, we aim to determine the in vitro activity of OSW-1 analogs (OA) isolated in our lab, as well as determine their interaction with OSBP and ORP4 proteins in multiple cancer cell lines. We mainly seek to determine the structure and ligand interaction with the OSBP-ligand binding domain (LBD) and full-length OSBP to shed light on the conformation changes that occur upon ligand binding. Preliminary data indicate that the tested OA compounds are active in multiple cancer cell lines with reduced OSBP levels effect, suggesting a similar mechanism of action to OSW-1. A transient expression of full-length OSBP and LBD showed that the truncated OSBP (LBD) was mostly found in the pellet, which could imply low solubility, while the full-length OSBP showed sufficient solubility. Our efforts are currently focused on purifying full-length OSBP. We are also working towards purifying full-length OSBP with a cleavage site that allows cutting out the LBD, thus solving the insolubility issue. Once obtained, the full-length OSBP and the ligand binding domain will be used for both binding and structure determination studies.

Citation Format: Ruth Fiona Bayimenye, Jorge L. Berrios-Rivera, Susan Nimmo, Christina R. Bourne, Anthony W. Burgett. Determining the structure and function relationship of the oxysterol-binding protein (OSBP) to guide drug development [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5778.
Abstract 5780: Simultaneous targeting existing proteins and nascent proteins for synergistic anticancer activity
Authors: Li Bingbing X. , Wang Jian , Chao Bo , Piesner Jake , Kelly Felice , Petrie Stefanie Kaech , Xiao Xiangshu
Published: March 2024

Protein synthesis and subsequent delivery to the target locations in cells are essential for their proper functions. Newly synthesized proteins and existing protein have differential properties that can potentially be exploited for targeting to maximize therapeutic potentials. Methods to label and distinguish newly synthesized proteins from existing ones are critical to assess their differential properties, but such methods are lacking. We describe the first chemical genetics-based approach for selective labeling of existing and newly synthesized proteins that we termed as CG-SLENP. Using HaloTag in-frame fusion with lamin A (LA), we demonstrate that the two pools of proteins can be selectively labeled using CG-SLENP in living cells (https://doi.org/10.1101/2023.11.02.565346). We further employ our recently developed selective small molecule ligand LBL1 for LA to probe the potential differences between newly synthesized and existing LA. Our results show that LBL1 can differentially modulate these two pools of LA. We further extend our CG-SLENP strategy to evaluate the differences of the two pools for BRD4 (bromodomain containing 4). These observed differences motivated us to investigate the synergistic anticancer properties of BRD4 degraders and inhibitors in triple negative breast cancer. Our results show that simultaneous targeting newly synthesized proteins and existing proteins display strong synergistic anticancer activities.

Citation Format: Bingbing X. Li, Jian Wang, Bo Chao, Jake Piesner, Felice Kelly, Stefanie Kaech Petrie, Xiangshu Xiao. Simultaneous targeting existing proteins and nascent proteins for synergistic anticancer activity [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5780.
Abstract 5792: Rapid and efficient generation of panels of T cell engaging (TCE) multispecific antibodies via complementary technologies
Authors: Ahonen Cory , Sharkey Nathan , Durkin Melissa , Avery Andrew , Battles Michael , Sharkey Beth , Barlow Kyle , Sivasubramanian Arvind , Stein Caitlin , Lunde Bradley , Schutz Kevin , Prinz Bianka , Pejchal Rob , Widboom Paul , Krauland Eric
Published: March 2024

A goal of immunotherapy is to induce an anti-tumor response that is potent and specific. However, there is increasing understanding that currently approved monospecific checkpoint inhibitors are not effective for all patients and/or indications. Thus, investigators are increasingly pursuing multispecific antibody treatments in an attempt to enhance clinical outcomes. These treatments may either take the form of mixtures (administered simultaneously or in series) of multiple monospecific antibodies, or as single entity, multispecific antibodies (‘multispecifics’). In the case of multispecifics, the large number of possible topologies and complexity of manufacture necessitate the development and application of a robust set of complementary technologies. We have developed an exemplary set of such technologies. Herein, we demonstrate the ability to direct desired antibody chain pairing (HC-HC and HC-LC), isolate and engineer single-domain antibodies, as well as generate large (>100) panels of multispecific antibodies with diverse topologies from a limited number of input molecules. These technologies can be leveraged in combination with our affinity and developability-optimized TCE αCD3 and αCD28 antibody panels to achieve desired potency without the need for additional discovery or engineering.

Citation Format: Cory Ahonen, Nathan Sharkey, Melissa Durkin, Andrew Avery, Michael Battles, Beth Sharkey, Kyle Barlow, Arvind Sivasubramanian, Caitlin Stein, Bradley Lunde, Kevin Schutz, Bianka Prinz, Rob Pejchal, Paul Widboom, Eric Krauland. Rapid and efficient generation of panels of T cell engaging (TCE) multispecific antibodies via complementary technologies [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5792.
Abstract 5796: A HER3 antibody that uniquely blocks the HER3 heterodimerization interface effectively inhibits tumor growth in pre-clinical models with potentially oncogenic HER3 mutations
Authors: Toy Weiyi , Thakkar Dipti , Magallanes Roberto , Wu Sharon , Poi Ming , Mas Alejandro , Paszkiewicz Konrad , Ingram Piers , Boyd-Kirkup Jerome
Published: March 2024

HER3 activation, via NRG1 ligand-dependent and -independent heterodimerization with HER2 or EGFR, has been associated with tumor progression and acquired resistance to therapies in multiple indications. HER3 mutations, detected in around 3% of cancer cases, may drive oncogenic signaling, leading to rapid tumor growth. Currently, there are no approved targeted therapies for HER3 mutations. Through analysis of real-world data and structural modelling of HER3 heterodimers, we identified four common HER3 mutations located within or close to the dimerization interface of HER3, suggesting a potential impact on HER3 heterodimerization. Immunoprecipitation assays confirmed that all four mutations increased the heterodimerization of HER3 with both HER2 and EGFR. Further, conversion of an endogenous HER3 mutation to wild type via CRISPR editing significantly reduced the growth of KYSE-150, a HER3 mutant cell line. HMBD-001 is a clinical-stage anti-HER3 antibody rationally developed to uniquely block the HER3 dimerization interface to potently inhibit HER3 heterodimerization. Through structural analysis and FACS binding on HER3 mutation cell lines, we confirmed that the binding epitope of HMBD-001 does not overlap with the selected HER3 mutations and therefore may be a good therapeutic option for patients with HER3 mutations. In vitro, HMBD-001 suppressed HER3 mutation-driven PI3K/AKT signaling, as demonstrated by the reduction of phosphorylated HER3 and AKT levels. In multiple cell- and patient-derived xenograft models with HER3 mutations HMBD-001 response achieved >80% tumor growth inhibition. Based on this encouraging preclinical data, a Phase Ib clinical trial (NCT05919537) has been initiated, evaluating HMBD-001 in patients with aberrant HER3 signaling, including HER3 mutations.

Citation Format: Weiyi Toy, Dipti Thakkar, Roberto Magallanes, Sharon Wu, Ming Poi, Alejandro Mas, Konrad Paszkiewicz, Piers Ingram, Jerome Boyd-Kirkup. A HER3 antibody that uniquely blocks the HER3 heterodimerization interface effectively inhibits tumor growth in pre-clinical models with potentially oncogenic HER3 mutations [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5796.
Abstract 5841: A genome wide CRISPR-Cas9 screen identifies mediators of resistance to dual PI3K/mTOR inhibition in glioblastoma multiforme
Authors: Ferrotta Annalisa V. , Izawa-Ishiguro Arianna , Grogan Meaghan , Mellinghoff Ingo K.
Published: March 2024

Glioblastoma multiforme (GBM) is a highly aggressive primary brain tumor with a devastating 5-year survival rate of 6.8%. The current standard of care, consisting of surgery, radiation, and temozolomide (TMZ), has remained unchanged for over the past 15 years despite its limited efficacy and the serious therapy-related adverse events associated to this regimen. Although some frequent genetic alterations have been identified in GBM, no targeted therapies have shown efficacy in these patients to date. Among these, the phosphoinositide 3-kinase (PI3K) pathway is a signaling network that regulates cell growth, proliferation, migration, and invasion. Extensive molecular characterization of GBM has identified alterations in the components of the PI3K pathway in 80% of primary GBMs, including amplification of receptor tyrosine kinases (RTKs), activating mutations in the PI3K catalytic subunit (PIK3CA), loss-of-function mutations in the PI3K regulatory subunit (PIK3R1), and loss of the major tumor suppressor of the pathway, phosphatase and tensin homologue (PTEN). Despite the universal upregulation of PI3K pathway signaling associated with these genetic alterations, clinical trials investigating PI3K inhibitors in GBM have failed due to insufficient antitumor activity and dose-limiting toxicities. To elucidate mechanisms of resistance to PI3K inhibition in GBM, we used a genome-wide functional CRISPR-Cas9 knockout screen to identify genes that mediate resistance to the dual PI3K/mTOR inhibitor XL765 in PTEN-null SF295 GBM cells. We identified reactivation of the PI3K pathway and inhibition of autophagy as potential resistance mechanisms to dual PI3K/mTOR inhibition. Using orthogonal approaches, we will functionally validate our candidate hits through mechanistic studies, with patient-derived models, and with in vivo orthotopic xenografts. Our findings will elucidate novel mechanisms of resistance to PI3K/mTOR inhibition in GBM and will streamline rational drug combinations aimed to overcome resistance, thus eventually maximizing therapeutic responses to PI3K inhibitors in GBM.

Citation Format: Annalisa V. Ferrotta, Arianna Izawa-Ishiguro, Meaghan Grogan, Ingo K. Mellinghoff. A genome wide CRISPR-Cas9 screen identifies mediators of resistance to dual PI3K/mTOR inhibition in glioblastoma multiforme [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5841.
Abstract 5879: Role of the inner mitochondrial membrane protein (Mic60) in MAPKi-resistant melanoma
Authors: Ghosh Jagadish C. , Aguila Segundo Del , Li Haiyin , Villanueva Jessie , Altieri Dario C.
Published: March 2024

Introduction: Metastatic melanoma is one of the most aggressive cancers, despite recent improvements in therapy. The rising melanoma incidence and mortality, along with its high propensity for metastasis highlights the urgency to find more effective therapeutic targets. The efficacy of targeted MAPK signaling pathway inhibitors (MAPKi) in metastatic melanoma therapy is limited by the development of resistance mechanisms that result in disease relapse. This situation necessitates alternative treatments for melanoma patients who develop resistance to targeted therapy. We have recently found out that there exists a group of human tumors that express lower levels of Mic60, a mitochondrial structural protein also known as mitofilin or inner membrane mitochondrial protein (IMMT). In a model of prostate cancer, we showed that Mic60-low tumors have lower mitochondrial fitness, but increased cell motility, invasion, and propensity to metastasize. However, a potential differential expression of Mic60 in melanoma has not been investigated and whether reduced mitochondrial fitness in Mic60-low tumors can expose new therapeutic vulnerabilities in combination with targeted therapies has not been determined.

Experimental Procedures: We analyzed melanoma-specific TMA for differential expression of Mic60 in tumor vs. adjacent normal tissue by IHC. Differential mRNA expression levels were examined by single-cell RNA-Seq and quantified by bioinformatics analysis. Differential therapeutic vulnerabilities of Mic60-low melanoma cell lines to mitochondrial-targeted small molecule Hsp90 inhibitor, Gamitrinib, were assessed for cell death induction and mitochondrial dysfunction.

Results: We identified subsets of melanoma patients with constitutively reduced or outright undetectable expression of Mic60, in vivo. By single-cell RNA-Seq, Mic60-low melanomas were characterized by reduced oxidative phosphorylation and decreased ATP production, slower cell cycle progression but paradoxically increased cell motility and invasion. Loss of Mic60 exposed new, actionable therapeutic vulnerabilities, and the combination of Gamitrinib plus MAPKi potently induced mitochondrial cell death in MAPKi-resistant melanoma cell lines.

Conclusion: Mic60 is heterogeneously expressed and often reduced in melanoma. Although this is associated with increased cell invasion and metastatic propensity, the combination of Gamitrinib plus MAPKi restored mitochondrial cell death in therapy-resistant, Mic60-low melanoma cells.

Citation Format: Jagadish C. Ghosh, Segundo Del Aguila, Haiyin Li, Jessie Villanueva, Dario C. Altieri. Role of the inner mitochondrial membrane protein (Mic60) in MAPKi-resistant melanoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5879.
Abstract 592: A novel pMEK inhibitor ABM-4095 for the treatment of pancreatic cancer
Authors: Xu Min , Hu Yong , Zhao Lanjiao , Chen Xiuquan , Chen Youqin , Yang Chen , Li Jizhi , Chen Chen , Lv Xiaobing
Published: March 2024

The MEK-ERK pathway is often activated in tumors by mutations of upstream BRAF- or RAS-proteins. The RAS is frequently mutated in several cancers, especially in pancreatic cancer with an about 95% rate. Pancreatic cancer has the highest mortality rate with a 5-year survival rate of 8% and a median survival of 6 months. Targeted therapies have been extensively evaluated in pancreatic cancer, however, survival improvement of this aggressive disease using a targeted strategy has been minimal. The only currently approved targeted therapy is erlotinib in combination with the chemotherapy drug gemcitabine. To date, four MEK inhibitors that block RAF-activation have been approved by the FDA, but their ability to inhibit ERK signal activated by RAS-mutations is limited due to the induction of MEK phosphorylation by relief of ERK-dependent feedback inhibition of RAF. Here, we report a novel small molecule, ATP-uncompetitive, pMEK inhibitor ABM-4095 that potently prevents phosphorylation of MEK by RAF with moderate inhibition of MEK kinase activity. Most of MEK inhibitors approved by FDA or in clinical trials increase pMEK levels instead. ABM-4095 has a good cell permeability. Its anti-cancer efficacy has been demonstrated both in the in vitro cancer cell line proliferation assay and in vivo xenograft models. ABM-4095 showed a synergy effect with erlotinib in pancreatic cancer cells. In a Miapaca-2 xenograft model, ABM-4095 showed good dose-dependent tumor inhibition as a single agent or combining with the KRAS G12C inhibitor AMG-510, and tumor regressions were observed. In summary, ABM-4095 is a potent pMEK inhibitor with a high activity against the RAS-mutant pancreatic cancer in vitro and in vivo. Detailed preclinical results will be presented.

Citation Format: Min Xu, Yong Hu, Lanjiao Zhao, Xiuquan Chen, Youqin Chen, Chen Yang, Jizhi Li, Chen Chen, Xiaobing Lv. A novel pMEK inhibitor ABM-4095 for the treatment of pancreatic cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 592.
Abstract 5923: Innovative cyclic peptide disrupts IL-17RB/MLK4 Interaction for targeted pancreatic cancer therapy
Authors: Lo Yung-Chen , Ko YL , Huang CH , Lee JH , Wu DN , Wu YT , Yu HM , hu Cn-Mei
Published: March 2024

Interleukin-17B (IL-17B) and its receptor IL-17RB drive oncogenic signaling in pancreatic cancer by interacting with mixed-lineage kinase 4 (MLK4) and phosphorylating IL-17RB's tyrosine-447 site. Our study highlights a therapeutic peptide (amino acids 403-416 of IL-17RB) that disrupts MLK4 binding. Improving its efficacy, we transformed the linear peptide into a disulfide-bonded cyclic form, exhibiting enhanced uptake and stability. The modified cyclic peptide outperformed the linear counterpart, effectively inhibiting the growth and metastasis of PDAC tumor cells in vitro and in a mouse model. Molecularly, we identified the critical role of cysteine (C) residue C408 in IL-17RB, mediating interaction with arginine (R)216 in MLK4's kinase domain. This interaction is pivotal for the cyclic peptide's efficacy. Additionally, lysine (K) residue K410 in IL-17RB maintains the cyclic peptide's structural integrity. These findings provide a comprehensive molecular understanding of IL-17RB and MLK4 interaction, offering innovative strategies for designing therapeutic molecules against pancreatic cancer.

Citation Format: Yung-Chen Lo, YL Ko, CH Huang, JH Lee, DN Wu, YT Wu, HM Yu, Cn-Mei hu. Innovative cyclic peptide disrupts IL-17RB/MLK4 Interaction for targeted pancreatic cancer therapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5923.
Abstract 5926: YB-1 inhibition as an effective approach for the treatment of osteosarcoma
Authors: Stefan Kirsten , Dheeraj Arpit , Tailor Dhanir , Davis Lara E. , Malhotra Sanjay V.
Published: March 2024

Background: Osteosarcoma (OS) is a bone cancer primarily affecting adolescents and young adults, with about 20% of patients having detectable metastatic disease at the time of diagnosis. Despite a large number of clinical trial efforts, metastatic sarcoma remains a lethal disease, and there have been no meaningful advances in therapy or improvements in patient outcomes for decades. Y-box binding protein 1 (YB-1) is a multifunctional cold-shock protein that translationally activates diverse stress response factors with pro-metastatic activities in many cancer types. Importantly, YB-1 is strongly associated with poor outcomes in sarcoma patients and is a major metastatic driver in high-risk sarcomas.

Methods: We recently described a novel compound, CET056, that inhibits cancer progression via YB-1 inhibition. We hypothesized that CET056 had the potential to suppress the progression of OS and could provide a new treatment for this disease. We screened osteosarcoma human and mouse cell lines for YB-1 protein expression. OS cells were functionally characterized for responses to CET056 in vitro and in vivo.

Results: YB-1 expression was seen in nearly all cell lines tested. CET056 treatment of OS cells resulted in reduced cell viability and YB-1 protein expression in a dose- and time- dependent manner, as well as reduced formation of colonies and spheroids. In vivo efficacy studies, which employed a syngeneic subcutaneous tumor model, revealed that CET056 effectively inhibited tumor progression and enhanced overall survival in contrast to vehicle treated control mice.

Conclusion: These results support our hypothesis and illustrate that YB-1 inhibition by CET056 is a promising candidate for further development as a therapy for OS.

Citation Format: Kirsten Stefan, Arpit Dheeraj, Dhanir Tailor, Lara E. Davis, Sanjay V. Malhotra. YB-1 inhibition as an effective approach for the treatment of osteosarcoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5926.
Abstract 5935: Non-allosteric inhibition of enolase 1 sensitizes triple-negative breast cancer for checkpoint inhibitors
Authors: Tailor Dhanir , Garcia-Marques Fernando Jose , Bermudez Abel , Li Wenqi , Dheeraj Arpit , Pitteri Sharon J. , Malhotra Sanjay V.
Published: March 2024

Background: Triple-negative breast cancer (TNBC) is an aggressive type of breast cancer that commonly returns and spreads. Currently, very few options are available for TNBC treatment. Cancer cells exploit glycolytic machinery for the Warburg effect and aerobic glycolysis. Enolase 1 (ENO1) is the glycolytic enzyme expressed in most tissues, and many cancer cells have higher expression. Apart from the glycolytic role in the cytosol, ENO1 also plays different roles in cancer cells, including as a surface receptor.

Method: non-allosteric chemical inhibition was developed and tested in vitro for its efficacy and target validation. Subsequently, in vivo examinations were conducted on emerging small molecules in syngeneic and patient-derived murine models of breast cancer to unveil their anti-tumor efficacy.

Results: Our non-allosteric small molecule inhibitor, SU212, binds to ENO1 and restricts its movement within cells. SU212 treatment leads to the accumulation of ENO1 in the nucleus where it restrains the activity of c-Myc. The treatment causes the production of truncated ENO1 called myc promoter-binding protein 1 (MBP-1), which limits the activity of c-Myc. Stand-alone treatment of SU212 restrains the tumor progression and metastasis in orthotopic syngeneic and PDX mouse models. Combining SU212 and Anti-PD1 significantly inhibits tumor growth and metastasis in mouse models. C-Myc is linked to protein transcription that aids immune resistance and tumor evasion of immune surveillance. Suppression of c-Myc activity via SU212 treatment sensitizes the TNBC tumors for anti-PD1 therapy.

Conclusions: This study provides compelling preclinical data for further development of SU0212 as an immune therapy sensitizer for the treatment of TNBC.

Citation Format: Dhanir Tailor, Fernando Jose Garcia-Marques, Abel Bermudez, Wenqi Li, Arpit Dheeraj, Sharon J. Pitteri, Sanjay V. Malhotra. Non-allosteric inhibition of enolase 1 sensitizes triple-negative breast cancer for checkpoint inhibitors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5935.
Abstract 5946: ZM-412, a potent and selective KIF18A inhibitor with robust efficacy as monotherapy in CIN-positive tumors and in combination with MMAE-conjugated ADC in CIN-negative tumors
Authors: Zhou Feng , Zhou Lei , Wang Ruina , Xue Liting , Qin Xiaokang , Li Zhengtao , Yu Jian , Tang Renhong
Published: March 2024

Chromosomal instability (CIN), a hallmark of human cancer, is defined as the perpetual missegregation of whole chromosomes during mitosis. KIF18A has emerged as a potential therapeutic target of synthetic lethality to induce CIN tumor cell death because it is more required for the proliferation of CIN tumor cells than normal diploidy cells. Here, we identified a potent and selective KIF18A inhibitor ZM-412. In vitro, ZM-412 inhibited the kinesin motor enzymatic activity with an IC50 less than 30 nM, and arrested OVCAR3 cells in the G2/M phase with an EC50 around 2.0 nM. ZM-412 also selectively inhibited the proliferation of a panel of CIN-positive tumor cell lines with IC50 values less than 50 nM, whereas it didn’t affect the proliferation of CIN-negative cells such as PBMC and near-diploidy HCT116 as indicated by IC50 values over than 5 μM. A CIN-positive HCT116CIN model was established by cytochalasin D induction. Compared to parent HCT116 cells, it was sensitive to ZM-412 treatment, suggesting the high selectivity of ZM-412 to CIN tumors as monotherapy. Both KIF18A inhibitors and monomethyl auristatin E (MMAE) regulate microtubule dynamics, which provides a potential combination strategy. ZM-412 showed a significantly synergic effect with free MMAE or MMAE-conjugated ADC on the inhibition of proliferation in multiple kinds of cancer cell lines, including CIN-positive/negative tumor cell lines. In vivo, ZM-412 potently inhibited tumor growth in a dose-dependent manner in OVCAR3 and HT29 xenograft models. Moreover, ZM-412 showed a remarkable synergic effect on tumor growth inhibition with MMAE-conjugated LIV-1 ADC in OVCAR3 xenograft model. In conclusion, we discovered ZM-412 as a novel potent and selective KIF18A inhibitor, which has potential for the treatment of CIN cancers as monotherapy and for combination therapies for extended cancer types with MMAE-ADC.

Citation Format: Feng Zhou, Lei Zhou, Ruina Wang, Liting Xue, Xiaokang Qin, Zhengtao Li, Jian Yu, Renhong Tang. ZM-412, a potent and selective KIF18A inhibitor with robust efficacy as monotherapy in CIN-positive tumors and in combination with MMAE-conjugated ADC in CIN-negative tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5946.
Abstract 5969: VRK1 can be a therapeutic target in small cell neuroendocrine carcinoma of the uterine cervix
Authors: Kobayashi Mariya , Nakagawa Satoshi , Kanda Mizuki , Kamei Yuji , Tatsuo Masuda , Kakuda Mamoru , Hiramatsu Kosuke , Kimura Toshihiro , Ueda Yutaka , Enomoto Takayuki , Inoue Masahiro , Kimura Tadashi
Published: March 2024

Objective: Small cell neuroendocrine carcinoma of the uterine cervix (SCNEC) is extremely rare but highly aggressive and its prognosis is usually poor. Vaccinia-related kinase (VRK)1 is a serine/threonine protein kinase that is involved in cell proliferation by regulating cell-cycle progression and inducing cell-cycle arrest in response to stress signals. VRK2 belongs to the same family as VRK1, and they are paralogs. VRK1 has been reported as a potential therapeutic target in nervous system tumors with low VRK2 expression. Previously, we identified high expression of VRK1 in SCNEC through proteomic analysis of isolated organoids. The objective of the present study is to investigate the effect of VRK1 on the proliferation of SCNEC and its potential as a therapeutic target.

Methods: The mRNA and protein expression of VRK1 and VRK2 in ten organoids and two cell lines derived from SCNEC were examined and compared with cervical cancer of other histological subtypes by RNA microarray and western blot analysis. The effect of VRK1 on tumor growth in vitro and in vivo (xenograft model) were evaluated by shRNA-mediated knockdown of VRK1 (shVRK1). RNA-seq was performed from the xenograft tumors. The effects of shVRK1 on cell proliferation were evaluated under various levels of oxidative stress induced by H2O2.

Results: VRK1 expression was higher in organoids and cell lines derived from SCNEC than those derived from squamous cell carcinoma and adenocarcinoma, while VRK2 expression was lower in SCNEC. Tumor growth was suppressed significantly by shVRK1 in vivo (mean weight: cell line 1: 0.62 vs 0.06g, p<0.05, 2: 1.79 vs 0.58g, p<0.01). Gene ontology analysis of RNA-seq data suggested that VRK1 is related to cellular responses to stress. Proliferation was slightly suppressed by shVRK1 under normal conditions; however, it was significantly enhanced under oxidative stress (Cell line 1: in shVRK1, -14.0% without oxidative stress vs -54.9% under H2O2 750μM, p<0.01, Cell line 2: similar to Cell line 1).

Conclusion: SCNEC exhibited high VRK1 and low VRK2 expression, and the tumor suppressive effect of shVRK1 was more significant in vivo than in vitro. VRK1 may play a role in the tumor microenvironment, including oxidative stress, and is a potential therapeutic target for SCNEC.

Citation Format: Mariya Kobayashi, Satoshi Nakagawa, Mizuki Kanda, Yuji Kamei, Masuda Tatsuo, Mamoru Kakuda, Kosuke Hiramatsu, Toshihiro Kimura, Yutaka Ueda, Takayuki Enomoto, Masahiro Inoue, Tadashi Kimura. VRK1 can be a therapeutic target in small cell neuroendocrine carcinoma of the uterine cervix [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5969.
Abstract 5976: R9: A novel NuRD complex inhibitor for targeted therapy in triple negative breast cancer (TNBC)
Authors: Zhang Kun , Jacob Sheeba , Dozmorov Mikhail , Babic Ivan , Nurmemmedov Elmar , Faber Anthony C.
Published: March 2024

Triple Negative Breast Cancer (TNBC) is a highly aggressive breast cancer subtype, disproportionately affecting young and African American populations. TNBC constitutes up to 15% of breast cancers that lack effective targeted therapy. The Nucleosome Remodeling and Deacetylase (NuRD) complex, a pivotal chromatin remodeling entity, plays a crucial role in cancer development and progression. Specifically, the NuRD complex associates with SALL4 in cancer cells, contributing to the silencing of tumor-suppressor genes like PTEN. In this study, we discover R9, a novel small-molecule nucleotide analog, a first-in-class NuRD inhibitor. Utilizing computational and cellular methods, R9 demonstrated selective engagement with RBBP4, a key NuRD complex subunit. Cellular target engagement technology has been utilized to verify direct interaction of R9 with NuRD complex as well as to guide medicinal chemistry efforts. Mass spectrometry thermal proteome profiling (TPP) affirmed RBBP4 as the primary target of R9 with minimal off-target effects. In vitro studies reveal R9 displaying robust toxicity in TNBC cells, while sparing normal tissue derived cells. Encouragingly, R9 effectively impeded TNBC tumors growth in mice without inducing toxicity. Mechanistically, we demonstrate R9 induces DNA damage in sensitive TNBC cells, and the sensitivity correlates to DNA damage-vulnerable cancer cells, indicating DNA damage is a major effector of NuRD complex inhibition in TNBCs. We further demonstrate that R9 induces DNA damage through a c-MYC dependent manner. Ongoing studies aim to elucidate key transcription factors involved in NuRD complex inhibition and the role of MYC and DNA damage in response to NuRD complex inhibition. This research positions R9 as a promising candidate for targeted therapy in TNBC, offering potential insights into the intricate molecular pathways involved in TNBC tumor progression.

Citation Format: Kun Zhang, Sheeba Jacob, Mikhail Dozmorov, Ivan Babic, Elmar Nurmemmedov, Anthony C. Faber. R9: A novel NuRD complex inhibitor for targeted therapy in triple negative breast cancer (TNBC) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5976.
Abstract 5990: Microtubule-associated serine/threonine kinase-likeinhibitor, AD1208, as a novel cancer therapeutics
Authors: CHOI SOONGYU , Ahn JS , Baek KS , Choi YL , Im MY , Kim JH , Kim JW , Khoo JH , Lee SH , Yao WL , Park Young-Whan
Published: March 2024

Microtubule-associated serine/threonine kinase-like is an essential regulator of mitosis and emerged as a novel oncogenic kinase. It is upregulated in several cancer types, correlating with chromosome instability and poor patient survival. Here, we are reporting a MASTL inhibitor, AD1208, as a new cancer therapeutics.AD1208 inhibits kinase activity of MASTL with IC50 value of 7nM in competitive manner against ATP and induces apoptosis of colorectal cancer cells with IC50 of 150nM. Selectivity index is higher than 100 folds when the cytotoxicity was measured in normal colon cells. Synthetic lethality with BRCA was observed in knock out studies. Cell panel analysis, consist of 300 cell lines, indicated that the AD1208 is effective in cancers originated from stomach, colon, leukemia, lymphoma, and soft tissue. In vivo efficacy was confirmed in mouse xenograft model in dose dependent manner and synergistic effect with PARP inhibitor was observed. Kinase Assay Panel screening revealed that AD1208 is highly selective against 468 kinases. Inhibition of MASTL resulted in decreasing phosphorylated ENSA, inactivating CDK1 and arresting cell cycle progression at G2/M phase. Clinical adverse drug reactions of AD1208 were predicted by in vitro Safety Functional Panel screening to exhibit no meaningful safety-related issues. Currently, AD1208 is being conducted in IND enabling GLP-Tox studies, including genotoxicity, mutagenicity, safety pharmacology as well as in vivo safety studies. Taken together, AD1208 is identified as a novel and selective MASTL inhibitor exhibiting significant therapeutic potential to be a development candidate.

Citation Format: SOONGYU CHOI, JS Ahn, KS Baek, YL Choi, MY Im, JH Kim, JW Kim, JH Khoo, SH Lee, WL Yao, Young-Whan Park. Microtubule-associated serine/threonine kinase-likeinhibitor, AD1208, as a novel cancer therapeutics [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5990.
Abstract 5999: Bitter taste receptors trigger pyroptosis and apoptosis through NLRP3 activation in oral cancer cells in response to a dysbiotic bacterial molecule: A possible role as pattern recognition receptors
Authors: Yu Seong , Lee Heesu , Shin Jeong Mu , Song Na-Young
Published: March 2024

Oral squamous cell carcinoma (OSCC) is the most common type of head and neck cancers. It has been reported that the composition of the oral microbiome was shifted in OSCC patients compared to healthy subjects. In particular, Pseudomonas aeruginosa is one of the most abundant oral microbes in OSCC patients. Bitter taste receptors (taste 2 receptors, TAS2Rs), known as G protein-coupled receptors (GPCRs), can recognize P. aeruginosa-derived quorum sensing molecules, such as N-(3-oxododecanoyl)-L-homoserine lactone (oxo-C12). Therefore, we explored the role of TAS2Rs in oral dysbiosis and cancers. Herein, we observed that TAS2Rs, such as TAS2R4, TAS2R14, and TAS2R38, mediated both pyroptosis and apoptosis, two distinct types of programmed cell death, in human OSCC HSC3 cells exposed to oxo-C12. Unexpectedly, TAS2Rs provoked pyroptosis and apoptosis in a GPCR-independent manner. Instead, TAS2Rs seemed to recruit NLRP3 inflammasome and subsequently activate caspase-8 in response to oxo-C12, implying the TAS2Rs-NLRP3-caspase-8 axis. Notably, the immunofluorescence staining showed considerable expression of TAS2Rs and NLRP3 in oxo-C12-treated HSC3 cells as well as human OSCC tissues, further supporting the presence of the alternative activation pathway of TAS2Rs. Moreover, siRNA knockdown of MyD88 diminished oxo-C12-induced NLRP3 activation, caspase-8 cleavage and cell death marker expression, which implies that MyD88 is involved in activation of the TAS2Rs-NLRP3-caspase-8 axis. This also suggests that TAS2Rs might function as potential pattern recognition receptors, similar to toll-like receptors responsible for recognition of pathogen and their molecules. Based on The Cancer Genome Atlas analysis, downregulation of TAS2Rs was correlated with poor prognosis in OSCC patients. Taken together, TAS2Rs might trigger the host defense mechanism against microbial dysbiosis-induced cancer development. Thus, TAS2Rs could be promising chemotherapeutic targets for OSCC treatment, particularly via disconnecting interkingdom molecular links between microbial alterations and carcinogenesis.

Citation Format: Seong Yu, Heesu Lee, Jeong Mu Shin, Na-Young Song. Bitter taste receptors trigger pyroptosis and apoptosis through NLRP3 activation in oral cancer cells in response to a dysbiotic bacterial molecule: A possible role as pattern recognition receptors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5999.
Abstract 6014: PLK1-dependent phosphorylation of PRMT5 promotes DNA damage response in prostate cancer
Authors: Peng Jia , Zhang Yanquan , Wang Jianlin , Li Qianjin , He Daheng , Wang Xinyi , Rao Xiongjian , Wu Meng , Mo Pingli , Wang Lei , Wu Sai , Wang Ruixin , Liu Jinghui , Nouri Mansoureh , Tadahide Izumi , Liu Xiaoqi
Published: March 2024

Prostate cancer stands out as the most frequently diagnosed cancer in men and is projected to be the second leading cause of cancer-related deaths among men in the US. Consequently, there is an urgent need for studies focusing on innovative therapeutic approaches. DNA Damage Response (DDR) is critical for cell survival, as it promotes genomic stability and reduces the risk of inheriting damage. DDR also promotes cancer cells' survival, making it a therapeutic target in cancer. PRMT5, an enzyme in the methyltransferase family, is frequently activated and overexpressed in various cancers, including prostate cancer. Furthermore, research has revealed that PRMT5 has been implicated in DDR in prostate cancer, and the regulation of PRMT5-dependent DDR is influenced by its phosphorylation. Polo-like kinase 1 (PLK1) is a serine/threonine kinase also reportedly involved in DDR in prostate cancer. Our preliminary study found that PRMT5 is positively correlated with PLK1 in prostate cancer based on the TCGA database. Nonetheless, the mechanism through which PRMT5 is regulated needs to be clarified. Here, we found that PLK1 phosphorylates PRMT5 at the S470 site, and this specific phosphorylation is required for maintaining the enzymatic activity of PRMT5. Moreover, Plk1-associated phosphorylation of PRMT5 subsequently promotes DNA damage repair, indicated by the decreasing level of γH2AX after DNA double-strand breaks (DSB). Our RNA-seq analyses of prostate cancer cells with wild-type or mutant S470 sites indicate that Plk1-associated phosphorylation on the S470 site exerts an influence on DNA replication and DDR pathways. These findings shed light on a novel perspective regarding the roles of PLK1-mediated PRMT5 phosphorylation in DDR, offering potential therapeutic strategies in prostate cancer.

Citation Format: Jia Peng, Yanquan Zhang, Jianlin Wang, Qianjin Li, Daheng He, Xinyi Wang, Xiongjian Rao, Meng Wu, Pingli Mo, Lei Wang, Sai Wu, Ruixin Wang, Jinghui Liu, Mansoureh Nouri, Izumi Tadahide, Xiaoqi Liu. PLK1-dependent phosphorylation of PRMT5 promotes DNA damage response in prostate cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6014.
Abstract 6047: Discovery and characterization of PVTX-321, an estrogen receptor heterobifunctional degrader
Authors: Havens Courtney G. , Xu Guozhang , Lowenstein Cass , Samanta Debangshu , Vidal Brian , Behshad Elham , Nagilla Rakesh , Russell Mike , Orth Peter , Wu Winston , Jolivette Larry , Priestley Scott , Mohammad Helai , Sui Zhihua
Published: March 2024

The estrogen receptor α (ERα) is a clinically validated target for the treatment of estrogen receptor-positive and human epidermal growth factor receptor 2-negative (ER+/HER2-) breast cancer. However, resistance to early line endocrine treatments due to mutations of the ESR1 gene encoding ERα is associated with poor prognosis and remains an area of unmet clinical need. ERα degradation using heterobifunctional degraders has emerged as a promising approach to tackle endocrine resistance through proteasome mediated degradation of the receptor. Here, we present the preclinical results for the development candidate, PVTX-321, an ERα heterobifunctional degrader. PVTX-321 is a rapid and potent ER heterobifunctional degrader as well as a full ERα antagonist. Both properties translate into potent antiproliferative activity across multiple ER+ breast cancer cell lines bearing either wild-type or clinically relevant ERα mutations (E380Q, Y537S and D538G). PVTX-321 demonstrates favorable oral bioavailability across different species and effectively induces dose-dependent degradation of ERα in vivo. Moreover, PVTX-321 achieves tumor regression as an oral agent at 10 mg/kg in MCF-7 mouse xenograft model. Furthermore, PVTX-321 possesses excellent in vitro and in vivo safety profiles and warrants further development for the treatment of ER+/HER2- breast cancer.

Citation Format: Courtney G. Havens, Guozhang Xu, Cass Lowenstein, Debangshu Samanta, Brian Vidal, Elham Behshad, Rakesh Nagilla, Mike Russell, Peter Orth, Winston Wu, Larry Jolivette, Scott Priestley, Helai Mohammad, Zhihua Sui. Discovery and characterization of PVTX-321, an estrogen receptor heterobifunctional degrader  [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6047.
Abstract 6070: Identification of a molecular glue degrader that engages a cancer-specific E3 ligase
Authors: Liu Yuan , Larsen Mads , Lin Bo , Cardenal Irene A. , Kennerdell Jason R. , Finkel Toren , Chen Bill B.
Published: March 2024

To date, most successful molecular glues have leveraged ubiquitously expressed E3 ligases, most notably Cereblon in the case of the thalidomide derivatives. However, a number of specific E3 ligases are highly over-expressed in certain tumors. Compounds that engage such tumor-specific E3 ligases might provide a unique opportunity to develop molecular glues with higher therapeutic indexes. One such tumor-specific E3 ligase is FBXO5, a member of the F-box family of E3 ligases. Expression analysis suggests this E3 ligase is highly expressed in a wide array of tumor tissues when compared to the corresponding normal tissue, and that within a given tumor type, higher FBXO5 expression correlates with advanced tumor stage and worse disease-free survival. Here, we describe a small molecule (MW~400 Daltons) that uses FBXO5 to function as a molecular glue degrader. This compound, CL-200, exerts cytotoxicity in the nanomolar range across a number of diverse tumor types. The cytotoxicity of CL-200 is abrogated when FBXO5 is knockdown using siRNA. We have further determined that CL-200 induces the FBXO5-dependent proteasomal degradation of at least two critical neosubstrates. One identified neosubstrate is the p150 isoform of ADAR1, an enzyme that catalyzes the posttranscriptional conversion of adenosine to inosine in double-stranded RNA (dsRNA). Evidence suggests that ADAR1p150 is the isoform that confers oncogenic and immune modulating effects in many tumors. Another neosubstrate targeted by CL-200 is c-myc, a critical transcription factor linked to a wide array of tumors. Of note, both p150 ADAR1 or c-myc have been viewed as difficult-to-drug if not undruggable targets. As such, these data suggests that CL-200 functions as a novel molecular glue degrader that engages the cancer-specific E3 ligase FBXO5 to degrade both p150 ADAR1 and c-myc. Structural alteration of CL-200 suggest that chemical modifications can be made that retain the engagement with FBXO5 while altering the neosubstrate profile. Together, these results demonstrate the possibility of leveraging cancer-specific E3 ligases to develop novel molecular glues.

Citation Format: Yuan Liu, Mads Larsen, Bo Lin, Irene A. Cardenal, Jason R. Kennerdell, Toren Finkel, Bill B. Chen. Identification of a molecular glue degrader that engages a cancer-specific E3 ligase [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6070.