bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract B104: U18666A-induced cholesterol accumulation decreases tumor-derived exosomes load and modulates malignant transformation
Authors: Beevi Syed Sultan , Verma Vinod Kumar
Published: December 2023

Background: Tumor-derived exosomes (TDEs) play an important role in the horizontal transfer of oncogenic information from the tumor to other sites, where they regulate pre-metastatic niche formation, organotropism, migration, invasion and survival. Cellular cholesterol homeostasis emerges as an important factor for exosomal biogenesis and cellular release. In this study, we utilized U18666A to trigger cholesterol accumulation within late endosomes of MDA-MB231 cells and evaluated the ability of exosomes derived from both U18666A-treated and untreated cells to initiate malignant transformation in recipient human epithelial kidney (HEK293) cells.

Methods: Exosomes were isolated and characterized from MDA-MB231 (untreated and U18666A-treated) and HEK293 cells. Cholesterol content of the cells and their associated exosomes were measured to confirm its accumulation following U18666A treatment. The effects of exosomes derived from untreated MDA-MB231 (UCE) and U18666A-treated MDA-MB231 (UTCE) cells on HEK293 cells were examined to determine their transforming potential.

Results: Exosomes derived from MDA-MB231 cells induced proliferation, migration, malignant transformation and epithelial-mesenchymal transition (EMT) process in non-cancerous recipients’ cells.  U18666A treatment led to accumulation of cholesterol within late endosomes and significantly reversed the EMT process in MDA-MB231 cells. It also reduced TAEs load from the cancer cells and rendered them less oncogenic which was evident from their inability to induce malignant transformation in the recipient HEK293 cells.

Conclusion: Modulation of cholesterol homeostasis and disruption of cholesterol supply to aggressive cancer cells can be an attractive strategy for limiting TAEs release as well as their subsequent role in cancer progression and metastasis.

Citation Format: Syed Sultan Beevi, Vinod Kumar Verma. U18666A-induced cholesterol accumulation decreases tumor-derived exosomes load and modulates malignant transformation [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr B104.
Abstract B178: Proteomics platform identifies vulnerabilities for specific DNA damage repair drugs
Authors: Arad Gali , Hay-Koren Avital , Futorian David , Fischman Oren , Daitchman Dina , Givton Ofer , Alchanati Iris , Katzenelenbogen Yonatan , Seger Eran , Pevzner Kirill
Published: December 2023

While poly-ADP-ribosylation (PAR) polymerase inhibitors (PARPi) are the only DNA damage repair (DDR) agent currently approved for clinical use, there are numerous ongoing clinical and preclinical drug development efforts of many other DDR-related targets, including ATR, ATM, CHK1 and others. One of the major challenges of these efforts is the ability to identify responsive populations and assign the right population for the right drug or drug combination. Patients are routinely assigned to PARPi or to on-going DDRi clinical trials based on the presence of BRCA mutation, or BRCAness profile encompassing various homologous recombination deficiencies (HRD). However, these biomarkers only partially represent the responsive populations, resulting in low response rates as well as misidentification of potential patient populations outside the genomic label. Since DNA replication and DNA repair mechanisms are dominated by signaling events, we hypothesized that HRD extends beyond the genomic status, and is manifested also in the level of protein expression and protein modification.In the current work, we compare the differences between cell lines that are either sensitive or resistant to a variety of DDR agents and highlight potential predictive biomarkers that are independent of HRD mutation status. We combined publicly available proteomic profiles of unperturbed cell lines, with both existing and newly generated proteomic and phosphoproteomic data of multiple cell lines before and after treatment of multiple DDR drugs.Analysis of HRD mutations showed that drug sensitivity is only partially explained by mutations. In addition, we found DNA replication and spliceosome as pathways that are consistently related to response regardless of drug and mutation status. While there is a general agreement between drugs in the pathway level, we identify smaller groups of proteins that are either drug or target-specific. We present here a proteogenomic approach to tackle the challenge of predictive biomarkers to DDR drugs. While DNA repair vulnerability is essential for DDR drug response, it is often not defined by mutations alone. We provide a proteomics-based framework that would enable future patient selection in DDR clinical trials.

Citation Format: Gali Arad, Avital Hay-Koren, David Futorian, Oren Fischman, Dina Daitchman, Ofer Givton, Iris Alchanati, Yonatan Katzenelenbogen, Eran Seger, Kirill Pevzner. Proteomics platform identifies vulnerabilities for specific DNA damage repair drugs [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr B178.
Abstract C006: BID upregulation associates with sensitivity to TTK inhibitors in tumor cell lines
Authors: Bertran-Alamillo Jordi , Giménez-Capitán Ana , García-Román Silvia , Rosell Rafael , Molina-Vila Miguel A
Published: December 2023

Background: Drugs overriding the spindle assembly checkpoint (SAC), such as Aurora kinase B (AURKB) or dual-specificity protein kinase TTK (=Mps1) inhibitors, are in Phase I/II clinical trials. However, their clinical application has been hampered by the lack of biomarkers for patient selection. We have previously demonstrated that BID upregulation, present in 6% of human tumors, predicts sensitivity to AURKB inhibition in cell line and animal models. Here, we investigated the association of BID expression with response to TTK inhibitors (TTKi).

Methods: A panel of seven solid tumor cell lines of lung, breast, melanoma, and pancreas origin were used in the study, together with three EGFR-mut clones derived from the PC9 lung cancer cell line. All of them had been previously characterized for BID expression at the mRNA and protein levels. The effects of three TTKi (BAY1217389, CFI-402257 and BOS172722) on proliferation, cell cycle and cell death were analyzed by MTT and flow cytometry, respectively. Silencing and ectopic expression with lentiviral vectors, together with transfection with a 72-gene knock-out library, were used to investigate mechanisms of action.

Results: The concordance in response to the three TTKi among the cell lines and clones analyzed was 100%. Three of the seven tumor cell lines and 2/3 EGFR-mut clones were uniformly sensitive, showing IC50s <100 nM  for CFI-402257 and BOS172722 and <10 nM for BAY1217389. BID expression was significantly associated with response to TTKi (p<0.05). All cells sensitive to TTKi had high BID mRNA and protein levels; while the cells with low BID were resistant. Flow cytometry showed G2/M arrest after TTKi in all lines and clones, followed by cell death only in those with high BID. Silencing using shRNA viral particles significantly reduced sensitivity to the three TTKi in the two sensitive cell lines and clones tested. Conversely, ectopic expression of BID in two resistant cell lines increased sensitivity to BAY1217389 and BOS172722. Finally, among a library of 72 genes, only knock-out of BID and the genes coding for the components of the PIDDosome (PIDD, CRADD and CASP2) triggered resistance to TTKi.

Conclusions: BID upregulation associates with sensitivity to TTKi through a mechanism involving the PIDDosome. Our results warrant clinical exploration of TTKi in BID overexpressing tumors.

Citation Format: Jordi Bertran-Alamillo, Ana Giménez-Capitán, Silvia García-Román, Rafael Rosell, Miguel A Molina-Vila. BID upregulation associates with sensitivity to TTK inhibitors in tumor cell lines [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr C006.
Abstract C007: Improved T-cell and B-cell receptor repertoire profiling and immunophenotyping for biomarker discovery
Authors: Chenchik Alex , Makhanov Mikhail , Liu Tianbing , Hu Dongfang , Ghias Khadija , Kobzik Lester
Published: December 2023

T-cell receptor (TCR) and B-cell receptor (BCR) repertoire profiling, also referred to as adaptive immune receptor repertoire (AIRR) profiling, holds great potential for the understanding of disease mechanisms and for the development of new treatments in infectious disease, autoimmunity, and immuno-oncology. This potential could be greatly improved by combining information about receptor clonotypes with immunophenotypes of T- and B- cells. A new technology we developed that combines profiling of all human TCR and BCR variable regions with phenotypic characterization of immune cells using the same workflow could be particularly useful. The TCR and BCR immunophenotyping method proposed involves RT-PCR amplification and sequencing of the CDR3 regions of the TCR and BCR genes, and subsequently determining the expression levels of the most informative T- and B-cell phenotyping genes. Preliminary results show that this method allows for comprehensive profiling of all seven TCR and BCR chains from a single sample, in a highly reproducible manner, directly from micro-samples including cancer tissue, whole blood, sorted cells and more. Bioinformatic analysis of the next-generation sequencing (NGS) data from the TCR and BCR clonotypes profile combined with RNA expression profiling of the same samples results in a richer data set that includes the identification of major immune cell subtypes and their activation status. Data from human cancer tissues and whole blood samples will be presented.

Citation Format: Alex Chenchik, Mikhail Makhanov, Tianbing Liu, Dongfang Hu, Khadija Ghias, Lester Kobzik. Improved T-cell and B-cell receptor repertoire profiling and immunophenotyping for biomarker discovery [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr C007.
Abstract C015: FGFR1 and RB1 genetic alteration impair clinical benefit of CDK4/6 inhibitors plus endocrine therapy in HR+/HER2- advanced breast cancer
Authors: Zhong Jianxin , Shao Bin , Jiang Hanfang , Li Huiping
Published: December 2023

Background: One of the great challenges for HR+/HER2- advanced breast cancer (ABC) is to determine who respond poorly to cyclin-dependent kinase 4/6 inhibitors (CDK4/6i). Chemotherapy is still used in HR+/HER2- patients. We aimed to explore cfDNA biomarkers for CDK4/6i plus endocrine therapy (ET), and compare its efficacy with chemotherapy in subgroups stratified by clinical and cfDNA characteristics.

Method: Patients diagnosed with HR+/HER2- advanced breast cancer underwent first-line CDK4/6i plus ET or chemotherapy in Peking University Cancer Hospital from January 2018 to June 2022 were enrolled in this study. Baseline blood samples of patients were collected before first-line treatment for cfDNA sequencing.

Results: Among all the 125 patients included in this study, the median PFS (mPFS) of CDK4/6i plus ET group (n=51) was significantly longer than patients treated with chemotherapy(n=74) (22.0 vs. 16.0 months, P = 0.025). In multivariate analysis, RB1 loss (Hazard ratio [HR] = 6.4, adjusted P = 0.031), FGFR1 gain (HR: 4.9, adjusted P = 0.030) were associated with shorter PFS of patients treated with CDK4/6i plus ET. A better efficacy of CDK4/6i plus ET was observed in patients with visceral metastasis, higher Ki-67 (≥20%) and smaller SLD (< 35mm) than chemotherapy. In subgroup analysis, interaction effects were found between RB1 loss (P interaction = 0.028), FGFR1 gain (P interaction = 0.004) and first-line treatment.

Conclusion: This study revealed that FGFR1 gain and RB1 loss are independent prognostic factors for PFS of CDK4/6i plus ET, and chemotherapy was not superior to CDK4/6i plus ET in the absence of FGFR1 gain and RB1 loss, which might improve selection of patients for CDK4/6 inhibitors.

Citation Format: Jianxin Zhong, Bin Shao, Hanfang Jiang, Huiping Li. FGFR1 and RB1 genetic alteration impair clinical benefit of CDK4/6 inhibitors plus endocrine therapy in HR+/HER2- advanced breast cancer [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr C015.
Abstract C017: Exploiting tumor RNA-sequencing data for prediction of immune checkpoint inhibition response
Authors: Mestdagh Pieter
Published: December 2023

Immune checkpoint inhibitors (ICI) have become the standard of care as a first- or second-line systemic treatment for patients with various cancer types. Unfortunately, many patients do not respond to this treatment and the occurrence of immune-related adverse events varies widely. There is an urgent need for robust predictive biomarkers for ICI response to select patients with likely clinical benefit from this costly treatment. Several biomarkers, aimed at predicting response to ICI, have been proposed, including PD-L1 expression, tumor mutation burden (TMB), infiltration of cytotoxic T-cells in the tumor, Microsatellite Instability (MSI) and expression of various immune gene signatures. However, these individual biomarkers have suboptimal performance and multiple complementary omics technologies are required to properly quantify them. Integration of these multi-omic biomarkers has proven valuable in increasing the accuracy and robustness of ICI response prediction. We have developed a computational pipeline that determines the expressed mutation burden (eTMB), MSI status, fraction of infiltrating immune cells and various immune gene expression signatures directly from the RNA-sequencing profile of the tumor. Each biomarker is quantified using a dedicated algorithm that applies machine learning (eTMB and MSI) or computational deconvolution (infiltrating immune cells) and integrates external data sources to maximize performance. Algorithm performance has been validated on large cohorts of tumor RNA-sequencing data with matching gold standard quantification of said biomarkers. Moreover, integrating these biomarkers improves prediction of response to checkpoint inhibition therapy. Taken together, our approach enables the quantification of various ICI response biomarkers from a single omics layer (RNA-seq) and can contribute to ICI response prediction.

Citation Format: Pieter Mestdagh. Exploiting tumor RNA-sequencing data for prediction of immune checkpoint inhibition response [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr C017.
Abstract C041: Drug repurposing to target TGF-β in chemoresistant high-grade serous ovarian cancer
Authors: Wong-Brown Michelle WY , Johnson Zlata , Salem Saad , Matthews Bayley G , Ford Caroline E , Marsh Deborah J , Bowden Nikola A
Published: December 2023

High-grade serous ovarian cancer (HGSOC) has low 5-year survival rate of 48%, due to chemotherapy resistance. Effective new therapies are required to improve the survival rate of HGSOC. TGF-β is a family of proteins associated with epithelial-mesenchymal transition and have been implicated in ovarian cancer progression and chemoresistance. Drugs that target TGF-β may have potential to be used to treat chemoresistant HGSOC and control tumour growth and progression. Drug repurposing is a strategy to identify new uses for approved drugs outside of their original indication, and ensure timely access to efficacious and cost-effective therapy for chemoresistant HGSOC. The aims of the study is to determine the effect of the repurposed drug teniposide on HGSOC cell growth, death, and apoptosis. A ligand-based screening was performed by Cresset Discovery for approved drugs that bind to the TGF-β receptor complex and ligand. Teniposide was shortlisted according to its dosing, lipid solubility, pharmacokinetics, and side effects. MTT assays were performed on eight molecularly-characterised HGSOC cell lines to obtain the IC50 of teniposide. The effect of the IC50 dose of teniposide on HGSOC cell growth, death, and apoptosis were monitored on the IncuCyte live-cell imager. Western blotting was performed to determine the expression of TGF-β signalling pathway proteins after treatment with teniposide. The average IC50 of teniposide in HGSOC cell lines is 10µM, within the range of the maximum plasma concentration (61µM). HGSOC cell lines treated with 10µM teniposide showed decreased cell growth, and increased cell death and apoptosis, similar to HGSOC cell lines treated with clinically-relevant dose of carboplatin (30µM). HGSOC cell lines treated with 10µM teniposide showed significantly higher cell death and apoptosis compared to treatment with 30µM carboplatin. Our preliminary results show that teniposide significantly reduced proliferation of HGSOC and has potential to be repurposed for treatment of chemoresistant HGSOC.

Citation Format: Michelle WY Wong-Brown, Zlata Johnson, Saad Salem, Bayley G Matthews, Caroline E Ford, Deborah J Marsh, Nikola A Bowden. Drug repurposing to target TGF-β in chemoresistant high-grade serous ovarian cancer [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr C041.
Abstract C050: Comprehensive analysis of causes for unsuccessful genomic profiling in a Phase 1 setting
Authors: Iden Cecilie , Belcaid Laila , Jacobsen Ida , Hoejgaard Martin , Spanggaard Iben , Mau-Soerensen Morten , Lassen Ulrik , Yde Christina Westmose , Rohrberg Kristoffer Staal
Published: December 2023

Purpose: Genomic profiling (GP) has revolutionized personalized cancer therapy, enabling tailored treatment strategies based on individual tumor characteristics. However, despite its widespread use, there are instances where GP fails. Understanding the causes of such failures is important for improving the success rate of GP. Here, we present a comprehensive analysis of unsuccessful GP within a phase 1 clinical setting.

Materials and Methods: A prospective, single-center, single-arm open label study (NCT02290522) was conducted, enrolling patients with advanced cancer referred to a phase I unit. Fresh tumor tissue was obtained by core needle biopsy for whole genome- or whole exome sequencing and RNA sequencing. In cases where fresh tumor tissue was unavailable, archival, formalin-fixed, paraffin-embedded tumor tissue or circulating tumor DNA extracted from plasma were obtained.

Results: Between March 2013 and December 2021, a total of 2151 patients with advanced cancers and exhausted or almost exhausted treatments options were enrolled in the study. GP was unsuccessful in 281 patients (13%). The reasons for failure were; abstaining from biopsy due to performance decline from the time of consent (115/281= 41%), inadequate tissue quality due to normal tissue or necrosis (52/281= 19%), absence of lesions for tissue biopsy at the time of biopsy (41/281= 15%), patient withdrawal of consent (23/281= 8%), pre-analytical factors preventing tissue or liquid biopsy analysis (14/281= 5%), unsuccessful analyses (13/281= 4%), other treatment initiated at time of planned biopsy (10/281= 4%), unknown reasons (9/281= 3%) or biopsy contraindicated (4/281= 1%).

Conclusion: The main cause of unsuccessful GP in this study was pre-analytical factors, primarily linked to performance status decline. Performing the biopsy and GP in earlier treatment lines, may reduce failure rates. Furthermore, considering the risk of rapid performance status decline, prior to biopsy referral, along with reduced lag time from obtaining consent to biopsy, may enhance GP success rates.

Citation Format: Cecilie Iden, Laila Belcaid, Ida Jacobsen, Martin Hoejgaard, Iben Spanggaard, Morten Mau-Soerensen, Ulrik Lassen, Christina Westmose Yde, Kristoffer Staal Rohrberg. Comprehensive analysis of causes for unsuccessful genomic profiling in a Phase 1 setting [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr C050.
Abstract C061: GNL3 promotes prostate cancer growth by regulating androgen receptor protein stability
Authors: Cheung Edwin , Zhang Cuiting
Published: December 2023

Androgen receptor (AR) is a primary driver of prostate cancer growth and development. Changes in AR coregulatoractivity or expression have severe consequences on the development of the disease. Using ChIP-MS, we discover G Protein Nucleolar 3 (GNL3) as a new AR transcriptional coactivator. We show that GNL3 helps the recruitment of AR to chromatin to directly control genes that support prostate cancer growth. We also demonstrate that GNL3 stabilizes AR by protecting it from ubiquitination and proteasomal degradation. We further determine that GNL3 is required for tumor progression by preventing cell-cycle arrest and apoptosis. Moreover, depleting GNL3 causes prostate cancer cells to be more susceptible to AR antagonists. Our work also indicates that Palbociclib, a CDK4/6 inhibitor, can be combined with enzalutamide to suppress cancer cell growth by downregulating AR and GNL3 co-regulated genes. From patient analyses, we observe that GNL3 expression is significantly elevated in many clinical studies. Finally, we reveal an AR-GNL3 gene signature in prostate tumors that is highly expressed and predicts disease recurrence. In summary, our results highlightthat GNL3 is a novel coactivator of AR and a potential target for the treatment of prostate cancer.

Citation Format: Edwin Cheung, Cuiting Zhang. GNL3 promotes prostate cancer growth by regulating androgen receptor protein stability [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr C061.
Abstract C081: Novel and selective inhibitors of KRASG12V
Authors: Bhavar Prashant Kashinath , Surampudi Uday Kumar
Published: December 2023

KRAS is one the most mutated proteins in cancers and are commonly identified in pancreatic adenocarcinoma, colorectal and non-small cell lung cancer. Owing to its role in a different human cancer, KRAS has long been considered as an important therapeutic target in precision oncology. Although KRAS was considered undruggable due to the protein’s structural complexity, recent allele specific inhibitors that covalently bind and trap KRAS in its inactive GDP bound state have demonstrated promising approach for generating anti RAS therapies and is validated by the accelerated approval of Sotorasib and Adagrasib by the FDA for patients with lung cancer. Success of targeting mutant KRASG12C has opened opportunities to tackle other oncogenic KRAS variants such as KRASG12V.  KRASG12V mutations occur frequently in multiple tumour histotypes such as adenocarcinoma of Pancreas (~32%), colorectal adenocarcinoma (~20%) and Lung (~19%) and represents a significant unmet medical need.  Here we describe preclinical profile of a potent and selective KRASG12V inhibitor VRTX171. VRTX171 is a tool compound that was potent across a KRASG12V mutated cancer cell line and found to be several fold less active in non-KRASG12V mutant cell lines.  Using a de novo drug design approach the compound was optimized to offer desired potency with high selectivity over WT KRAS and other KRAS mutant isoforms. Affinity for target protein, was assessed by HTRF based target engagement assay and inhibition of Raf/Mitogen-activated protein kinase (MAPK) pathway was determined using Western blot analysis in multiple cancer cell lines harbouring KRASG12V mutation. In-vivo studies of VRTX171 in Xenograft models harbouring KRASG12V mutations, as single agent as well as in combination with other targeted therapies are under consideration.

Citation Format: Prashant Kashinath Bhavar, Uday Kumar Surampudi. Novel and selective inhibitors of KRASG12V [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr C081.
Abstract C150: Targeted inhibition of homologous recombination and nonhomologous end joining in diffuse intrinsic pontine gliomas to prevent tumor recurrence
Authors: Barravecchia Ivana , Sharma Monika , Teis Robert , Cruz Jeanette , Mumby Rachel , Ziemke Elizabeth , Espinoza Carlos , Magnuson Brian , Ljungman Mats , Koschmann Carl , Whitehead Christopher , Sebolt-Leopold Judith , Galban Stefanie
Published: December 2023

Therapeutic resistance remains a major obstacle to successful clinical management of Diffuse Intrinsic Pontine Glioma (DIPG), a high-grade pediatric tumor of the brain stem. In nearly all patients, available therapies fail to prevent progression. Innovative combinatorial therapies that penetrate the blood-brain barrier and lead to long-term control of tumor growth are desperately needed. We identified mechanisms of resistance to radiotherapy, the standard of care for DIPG. Based on these findings, we rationally designed a brain-penetrant small molecule, MTX-241F, that is a highly selective inhibitor of EGFR and PI3 kinase family members, including the DNA repair protein DNA-PK. Preliminary studies demonstrate that micromolar levels of this inhibitor can be achieved in murine brain tissue and that MTX-241F exhibits promising single-agent efficacy and radiosensitizing activity in patient-derived DIPG neurospheres. Its physiochemical properties include high exposure in the brain, indicating excellent brain penetrance. Since radiotherapy results in double-strand breaks that are repaired by homologous recombination (HR) and non-homologous DNA end joining (NHEJ), we have tested the combination of MTX-241F with an inhibitor of ATM to achieve blockade of HR and NHEJ, respectively, with or without radiotherapy. When HR blockers were combined with MTX-241F and radiotherapy, synthetic lethality was observed, providing impetus to explore this combination in clinically relevant models of DIPG.   Our data provide proof-of-concept evidence to support advanced development of MTX-241F for the treatment of DIPG.  Future studies will be designed to inform rapid clinical translation to ultimately impact patients diagnosed with this devastating disease.

Citation Format: Ivana Barravecchia, Monika Sharma, Robert Teis, Jeanette Cruz, Rachel Mumby, Elizabeth Ziemke, Carlos Espinoza, Brian Magnuson, Mats Ljungman, Carl Koschmann, Christopher Whitehead, Judith Sebolt-Leopold, Stefanie Galban. Targeted inhibition of homologous recombination and nonhomologous end joining in diffuse intrinsic pontine gliomas to prevent tumor recurrence [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr C150.
Abstract C161: Identification of a reversible selective FGFR2 clinical development candidate with potency against gatekeeper and molecular brake mutations
Authors: Fischer John , Bouhana Karyn , Brizendine Richard , Chicarelli Mark , Fell Brad , Fulton Jennifer , Guarnieri Anna , Haygood Leyla , Jalluri Ravi , Johnson Amber , Koch Keith , Koslov-Davino Erika , Mejia Max , Rieger Rob , Robinson John , Rodriguez Mareli , Sullivan Francis , Wang Yang , Winski Shannon , Wood Silas , Zhou Yeyun
Published: December 2023

Approved FGFR inhibitors have demonstrated responses in patients that harbor FGFR genetic alterations but show reduced activity in patients with gatekeeper and molecular brake mutations.  In addition, efficacy of these agents may be reduced due to inhibition of FGFR1 and associated dose-limiting hyperphosphatemia.  To address these issues, a novel series of reversible FGFR2 inhibitors with activity against clinically relevant mutations and selectivity over FGFR1 has been identified. The inhibition of FGFR2 phosphorylation in engineered cell lines demonstrated activity toward wild-type FGFR2, molecular brake mutations N549H/K, and gatekeeper mutations V564I/F/L. Selectivity of these inhibitors against FGFR1 could lead to fewer dose limiting toxicities compared to approved FGFR inhibitors.  From this series, the identification of the clinical development candidate as a potent selective reversible FGFR2 inhibitor is described.  In vivo characterization to be presented includes dose escalating rodent pharmacokinetics (PK), second species PK, and efficacy in AN3 CA tumor bearing mouse models.

Citation Format: John Fischer, Karyn Bouhana, Richard Brizendine, Mark Chicarelli, Brad Fell, Jennifer Fulton, Anna Guarnieri, Leyla Haygood, Ravi Jalluri, Amber Johnson, Keith Koch, Erika Koslov-Davino, Max Mejia, Rob Rieger, John Robinson, Mareli Rodriguez, Francis Sullivan, Yang Wang, Shannon Winski, Silas Wood, Yeyun Zhou. Identification of a reversible selective FGFR2 clinical development candidate with potency against gatekeeper and molecular brake mutations [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr C161.
Abstract IA012: REGN10597: A PD-1-targeted, receptor-masked wild type IL-2 with improved therapeutic window for cancer immunotherapy
Authors: Wu Jiaxi , Bloch Nicolin , Chang Aaron , Bhavsar Ramandeep , Wang Qingqing , Patel Supriya , Garg Vidur , Shakil Hassan , Amatulli Michael , Dudgeon Drew , Yan Yuetian , Wang Shunhai , Ramos Willy , Krueger Pamela , Vazzana Kristin , Crawford Alison , Idun Jacqueline , Decker Corinne , DiLillo David , Chandwani Samira , Huang Tammy , Kirshner Jessica , Guo Chungguang , Macdonald Lynn , Ullman Erica , Hermann Aynur , Olson William , Davis Samuel , Lin John , Smith Eric , Zhang Tong
Published: December 2023

Recombinant IL-2 has been used for the treatment of metastatic melanoma and renal cell carcinoma, and induced complete, durable tumor regression in some patients. ​However, its broader use in cancer immunotherapy has been limited by severe toxicity. Here, we describe the development of REGN10597, a PD-1-targeted, receptor-masked IL-2 immunocytokine with attenuated systemic IL-2 activity but maintained capacity to engage endogenous IL-2Ra on PD-1+ T cells. We will share preclinical data on in vitro characterization as well as in vivo efficacy and toxicity studies of REGN10597.

Citation Format: Jiaxi Wu, Nicolin Bloch, Aaron Chang, Ramandeep Bhavsar, Qingqing Wang, Supriya Patel, Vidur Garg, Hassan Shakil, Michael Amatulli, Drew Dudgeon, Yuetian Yan, Shunhai Wang, Willy Ramos, Pamela Krueger, Kristin Vazzana, Alison Crawford, Jacqueline Idun, Corinne Decker, David DiLillo, Samira Chandwani, Tammy Huang, Jessica Kirshner, Chungguang Guo, Lynn Macdonald, Erica Ullman, Aynur Hermann, William Olson, Samuel Davis, John Lin, Eric Smith, Tong Zhang. REGN10597: A PD-1-targeted, receptor-masked wild type IL-2 with improved therapeutic window for cancer immunotherapy [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr IA012.
Abstract IA013: Integrating natural product samples back into drug screening programs
Authors: O'Keefe Barry R.
Published: December 2023

Natural products have a proven track record in use as anti-cancer agents. As of 2020 natural products (NPs), NP pharmacophores, and NP mimics represent a significant percentage of small molecule-based anti-cancer drugs. However, accessing the potential of NPs in high-throughput screening (HTS) campaigns has been challenging due to the complexity of the crude NP extracts, the time necessary for follow-up isolation efforts, and indefinite capabilities for resupply. This has resulted in NP-based libraries being significantly underrepresented in most recent large-scale HTS programs.  The US National Cancer Institute’s Natural Product Extract Repository is one of the world’s largest, most diverse collections of natural products containing >200,000 unique extracts derived from plant, marine and microbial organisms. To address the challenges in screening NPs and encourage increased assay of NP chemical diversity, the NCI created a Program for Natural Product Discovery (NPNPD) which has developed an automated, high-throughput robotics platform that has created 500,000 pre-fractionated NP samples and released them to the public for screening. In addition, automated secondary purification and structure elucidation systems were created that significantly decrease costs and timelines. This presentation will discuss the reasons for, challenges to, and mechanisms by which the NCI is working to increase the pace and efficiency of NP-based drug discovery.

Citation Format: Barry R. O'Keefe. Integrating natural product samples back into drug screening programs [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr IA013.
Abstract LB_A24: Baicalein suppresses tumorigenesis of the ER𝛼 positive of breast cancer cells by targeting multiple signaling pathways
Authors: Xhabija Besa , McLaughlin Aidan J. , Epelle Ibiere Lovelyn , Nielson Tristan H. , Ujeniuc Elisabeta , Duhaini Mariam I.
Published: December 2023

The anti-tumor properties of baicalein, a flavonoid compound, have been extensively documented. However, the specific effects of baicalein on ER𝛼 positive breast cancer cell lines, namely T47-D and MCF-7, are less well-known. In this study, we conducted comprehensive in vitro experiments to elucidate the comparative impacts of baicalein on these two cell lines. Our results demonstrate that baicalein exerts robust anti-cancer effects, inducing morphological changes, reducing colony formation, and inhibiting cell proliferation in both T47-D and MCF-7 cells. These effects were more pronounced at higher concentrations. Additionally, baicalein treatment impeded the migratory capabilities of both cell lines, as shown by wound healing assays. Furthermore, our data show that baicalein triggers apoptosis, leading to an increase in early apoptotic, late apoptotic, and dead cells. This apoptotic process appears to be caspase 3/7-dependent. Interestingly, the pro-apoptotic effects were more potent in T47-D cells, accompanied by significant upregulation of pro-apoptotic genes and downregulation of anti-apoptotic markers. Baicalein treatment also induced oxidative stress and DNA damage, evidenced by an increase in reactive oxygen species (ROS) and phosphorylation of ATM and H2A.X. Importantly, baicalein inhibited the PI3K signaling pathway, a key mediator of cancer progression. Genome-wide transcriptomic analysis revealed significant changes in gene expression patterns, with baicalein treatment causing both upregulation and downregulation of several genes. Pathway analysis revealed that cell cycle and ferroptosis pathways were activated in both cell lines upon baicalein treatment. In conclusion, our findings highlight the potential of baicalein as a therapeutic agent against breast cancer, while also revealing nuanced differences in response between the T47-D and MCF-7 breast cancer cell lines.

Citation Format: Besa Xhabija, Aidan J. McLaughlin, Ibiere Lovelyn Epelle, Tristan H. Nielson, Elisabeta Ujeniuc, Mariam I. Duhaini. Baicalein suppresses tumorigenesis of the ER𝛼 positive of breast cancer cells by targeting multiple signaling pathways [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr LB_A24.
Abstract LB_B03: Lentivirus-induced ALDH1L1 knock-in inhibits proliferation and migration and activates apoptosis of human A549 lung adenocarcinoma cells
Authors: Abdellatef Amira , Krupenko Sergey
Published: December 2023

Lung Adenocarcinoma (LUAD), one of the most common life-threatening malignancies worldwide, represents about 40% of all lung cancers. Human Protein Atlas and OncoLnc database indicate that LUAD tumors have significantly lower mRNA levels of ALDH1L1 (10-formyltetrahydrofolate dehydrogenase, a regulatory enzyme in folate metabolism) than in non-tumor lung tissues. Moreover, higher intratumoral ALDH1L1 expression in LUAD patients correlates with better clinical outcome. These findings raise the question of whether ALDH1L1 knock-in can have a therapeutic effect. As the first step in addressing this question, we knocked-in ALDH1L1 in A549 lung adenocarcinoma cells using the lentiviral delivery. Of note, as most cancer cell lines, A549 cells do not express ALDH1L1. We have constructed the lentiviral vector carrying ALDH1L1 and green fluorescent protein (EGFP) cDNA under the control of CMV and SV40 promoters, respectively. Recombinant lentivirus (Lv-ALDH1L1), generated and packed in HEK293 cells, was used to transduce A549 cells. The efficiency of the transduction was evaluated by monitoring the GFP expression using the fluorescence microscopy of live cells. The expression of ALDH1L1 was determined at the mRNA and protein levels by RT-PCR and western blot assays, accordingly. Our results showed a significant expression of ALDH1L1 mRNA and protein expression in A549 cells carrying the Lv-ALDH1L1 vector. The lentivirus-induced ALDH1L1 elevation produced strong inhibitory effects on cellular proliferation and colony formation under nutrient-rich conditions. Of note, it also induced alterations of cell morphology. To explore the underlying mechanisms of these effects, apoptosis-related markers were examined. Elevated levels of the signal transduction pathways involved in initiating apoptosis; BID, BAX, and BAK in A549 cells transduced with Lv-ALDH1L1 were observed. Furthermore, using the wound healing assay, we showed that ALDH1L1 strongly suppresses the migratory ability of A549 cells. Interestingly, this effect was associated with a robust down-regulation of the actin depolymerizing factor cofilin and its phosphorylated form. Overall, this study demonstrated that lentiviral ALDH1L1 knock-in produces strong anti-tumorigenesis effects in A549 cells. This further suggests that ALDH1L1 should be investigated as a therapeutic drug target in cancer treatment.

Citation Format: Amira Abdellatef, Sergey Krupenko. Lentivirus-induced ALDH1L1 knock-in inhibits proliferation and migration and activates apoptosis of human A549 lung adenocarcinoma cells [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr LB_B03.
Abstract LB_B07: Probability of negative impact on adherence caused by the most frequent side effects of adjuvant endocrine therapy for premenopausal breast cancer in SOFT and TEXT Trials
Authors: Qurayshah Tariq Hassan AL
Published: December 2023

Background:  Regardless of adjuvant chemotherapy, the addition of ovarian function suppression (OFS) to adjuvant endocrine therapy tamoxifen or exemestane in pre-menopausal women with estrogen receptor (ER)-positive breast cancer cause adverse events may affect adherence. Among the 22 targeted adverse events systematically reported in SOFT and TEXT trials, adverse events commonly experienced in exemestane–OFS group (32.3%) and tamoxifen–OFS group (31.0%), compared with tamoxifen alone group (24.6%). Side effects associated with endocrine therapy cause negative impact on adherence. Early discontinuation of endocrine therapy in 22.5%, 19.3%, and 23.7% of the tamoxifen, tamoxifen–OFS, and exemestane–OFS groups, respectively, in SOFT and TEXT trials. This report is intended to evaluate the possible contribution of the 8 most frequently studied side effects that have negative impact on adherence to hormone therapy in breast cancer. Methods: Calculating the probability of negative impact of most frequent endocrine therapy`s side effects (per SOFT-TEXT trials) on adherence per Leanne Fleming et al quantitative systematic review “The impact of medication side effects on adherence and persistence to hormone therapy in breast cancer survivors” Results: Musculoskeletal/joint pain had the most negative impact on the adherence in tamoxifen, tamoxifen–OFS, and exemestane–OFS groups (56%, 63% and 73%, respectively). Average of negative impact of tamoxifen, tamoxifen–OFS, and exemestane–OFS on adherence is 22%, 25% and 27%) Conclusions: The probability of adherence of using tamoxifen alone seems better than tamoxifen–OFS and exemestane–OFS.

Citation Format: Tariq Hassan AL Qurayshah. Probability of negative impact on adherence caused by the most frequent side effects of adjuvant endocrine therapy for premenopausal breast cancer in SOFT and TEXT Trials [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr LB_B07.
Abstract LB_B21: Extracellular RNA signatures of mutant KRAS-driven lung cancer
Authors: Maroli Sree Lakshmi Velandi , Reggiardo Roman E , Khojah Reem , Kim Daniel H
Published: December 2023

RAS genes are the most frequently mutated oncogenes in cancer, yet the effects of oncogenic RAS signaling on the noncoding transcriptome remain unclear. We analyzed the transcriptomes of human airway and bronchial epithelial cells transformed with mutant KRAS to define the landscape of KRAS-regulated noncoding RNAs. We find that oncogenic KRAS signaling upregulates noncoding transcripts throughout the genome, many of which arise from transposable elements (TEs). These TE RNAs exhibit differential expression and are regulated by KRAB zinc-finger (KZNF) genes, which are broadly downregulated in mutant KRAS cells and lung adenocarcinomas in vivo. Using both affinity- and nanofiltration-based EV isolation approaches, we show that specific TE RNAs, lncRNAs, and mRNAs, some of which are prognostic for lung adenocarcinoma (LUAD) patient survival, are preferentially released in extracellular vesicles (EVs). Moreover, we find that inhibition of oncogenic KRAS signaling broadly reprograms the noncoding transcriptome, as evidenced by a substantial increase in TE RNA secretion.  Mutant KRAS inhibition also increases the abundance of secreted lncRNAs and retained intron-containing transcripts, while decreasing the mRNA content of EVs. Notably, oncogenic KRAS signaling is required for the secretion of mRNAs from a set of 20 genes that are significantly associated with unfavorable clinical outcomes in LUAD. Our results indicate that mutant KRAS remodels the repetitive noncoding transcriptome, demonstrating the broad scope of intracellular and extracellular RNAs regulated by this oncogenic signaling pathway. Our study also suggests that both coding and noncoding RNAs that are secreted in EVs may serve as mutant KRAS-specific signatures for diagnosing lung cancer via minimally invasive RNA liquid biopsy technology, which we are currently developing as a companion diagnostic for mutant KRAS-targeting therapies.

Citation Format: Sree Lakshmi Velandi Maroli, Roman E Reggiardo, Reem Khojah, Daniel H Kim. Extracellular RNA signatures of mutant KRAS-driven lung cancer [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr LB_B21.
Abstract LB_B23: Magnetospirillum magneticum promotes iron competition and triggers apoptosis in human cancer cells
Authors: Menghini Stefano , Vizovišek Matej , Ho Ping Shu , Enders Jonathas , Schürle Simone
Published: December 2023

Bacteria are increasingly envisioned as living agents that can be administered to patients to carry out therapeutic actions. Interest has been growing over the past years in harnessing these microorganisms for cancer treatment as dynamic vectors with enhanced tumor-targeting properties. While bacterial traits, such as modulation of an immune response, local secretion of toxins, and proliferation in tumors have been well studied, less is known about bacteria as competitors for nutrients. We, therefore, investigated the use of magnetotactic bacteria as living iron chelators in the tumor microenvironment by studying the resulting competition for this vital nutrient, and by investigating the consequent metabolic effects in cancer cells. To do this, we first recreated a hypoxic environment by establishing an in vitro co-culture system consisting of the magnetotactic strain Magnetospirillum magneticum AMB-1 incubated under low-oxygen conditions with human cancer cells. We first quantified bacterial siderophore production and found it to be equivalent to a relevant concentration of deferoxamine (DFO), a potent drug used in iron chelation therapy. Further experiments then revealed an increased expression of transferrin receptor 1 (TfR1) on the cell surface and a significant decrease of viability in various cancer cell lines, indicating the bacteria’s ability to alter iron homeostasis. Metabolic effects exerted by AMB-1 were then further investigated. We demonstrated a lower rate of cellular proliferation correlating with a growing ratio of bacteria to cancer cells. Additional experiments also confirmed elevated apoptotic states and an enhanced activity level of executioner caspases in cancer cells, with an increasing number of AMB-1 in the culture. Lastly, the performed assays uncovered several apoptosis-related proteins that displayed altered levels when AMB-1 bacteria were added to the culture. Overall, our findings show the potential of magnetotactic bacteria to act as self-replicating iron-chelating agents that interfere with the iron homeostasis of cancer cells and decrease cancer cell viability. The presented data suggests involvement of triggered apoptotic signals that correlate with an increasing number of AMB-1 in the culture. This intrinsic capability of AMB-1 to induce apoptosis in breast cancer cells thus represents an encouraging strategy that could serve as an additional antineoplastic approach to reinforce current bacterial cancer therapies.

Citation Format: Stefano Menghini, Matej Vizovišek, Ping Shu Ho, Jonathas Enders, Simone Schürle. Magnetospirillum magneticum promotes iron competition and triggers apoptosis in human cancer cells [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr LB_B23.