bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract 7113: Targeting the repair of DNA-protein crosslinks induced by bifunctional alkylating agents
Authors: Turner Cole , Cerrato Hailey , Melehov Victoria , Healy Charlotte , Rice Kevin P. 
Published: March 2024

Abstract
Bifunctional alkylating agents, such as nitrosoureas, platinum-based therapeutics, and chloroethylhydrazines, have demonstrated clinical successes against cancer by inducing cytotoxic interstrand or intrastrand DNA crosslinks. However, the less well-characterized capacity of these agents to couple DNA to chromosomally-associated proteins may also contribute to these compounds’ observed cytotoxicities. Bulky DNA-protein crosslinks (DPCs) could obstruct the DNA metabolism critical to cancer proliferation, thus contribute to genomic instability and cell death. To endogenously repair DPCs, human cells often utilize a DPC-specific proteolytic mechanism dependent on the metalloprotease SPRTN. Complementary approaches for quantifying DPCs, generated ex vivo, to assess the capacity of several bifunctional alkylating agents to induce these lesions in cultured human leukemia cells are presented here. In the first approach, proteins were isolated from lysates of drug-treated cells and protein-bound DNA was quantified as a ratio to the total DNA present in the lysates. In the complementary approach, DNA was extracted from lysates of drug-treated cells using a modified ‘STAR’ assay in which genomic DNA is isolated and the DNA-bound proteins were quantified by fluorescein isothiocyanate labeling. Micromolar concentrations of the nitrogen mustard mechlorethamine and nitrosourea lomustine induced significant DPC formation while more modest DPC formation was observed using similar concentrations of the chloroethylating agents carmustine and laromustine, as well as cisplatin. Bifunctional alkylating agents dependent on epoxide functionality, including dianhydrogalacticol and diepoxybutane, required drug concentrations of at least one order of magnitude larger to produce similar DPC yields measurable by these techniques. A strategy to interfere with the DPC repair pathway via SPRTN knockdown and assess increased sensitivity of cancer cells to bifunctional alkylating agents is also presented. Chemotherapeutic sensitization by targeting SPRTN could suggest a therapeutic strategy to improve effectiveness of several DNA-targeted anticancer agents, especially if extended to other therapeutics that trap DPCs such as inhibitors of topoisomerase and poly(ADP-ribose) polymerase. Further, identifying structure-function relationships with respect to bifunctional alkylating agents and DPC formation could inform the future development and clinical utilization of these chemotherapies.
Citation Format: Cole Turner, Hailey Cerrato, Victoria Melehov, Charlotte Healy, Kevin P. Rice. Targeting the repair of DNA-protein crosslinks induced by bifunctional alkylating agents [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 7113.
Abstract 7117: Convection enhanced delivery of a novel ATR inhibitor synergizes with systemic lomustine for improved treatment of glioblastoma
Authors: Josowitz Alexander , Lee Teresa , Sundaram Ranjini K. , Pothupitiya Jinal , Brown Eric J. , Sule Amrita , Beckta Jason , Wang Yongheng , Vacca Joseph , Gilad Oren , Bindra Ranjit S. , Saltzman W Mark 
Published: March 2024

Abstract
Developing effective strategies for treating glioblastoma (GBM), the most common and aggressive form of brain cancer, has been a long-standing challenge. Despite rigorous treatment regimens including surgical resection with concomitant radiotherapy and chemotherapy, the prognosis for this disease remains poor, largely due to tumor recurrence, resistance to conventional therapeutics, pharmacokinetic and brain delivery challenges, and dose-limiting toxicities of existing therapies. The DNA damage response and DNA repair mechanisms such as the ataxia telangiectasia and Rad3-related (ATR) pathway are key mediators of therapeutic responses, and recent studies have shown that targeting DNA repair proteins alongside standard-of-care options is a promising anti-tumor strategy. Here, we employ a combination approach using a next-generation macrocyclic ATR inhibitor, ATRIN-333, to sensitize GBM tumors to alkylators. We establish the potency of ATRIN-333 and report a robust synergistic interaction between it and the alkylator lomustine in GBM cell-based assays and in a murine flank tumor model. This combinatorial treatment was then applied to a mouse intracranial tumor model, where we utilized a convection enhanced delivery (CED) system combined with nanoparticle technology for direct intracranial administration of ATRIN-333. ATRIN-333 was successfully encapsulated into a novel polymeric nanoparticle formulation using poly(ethylene glycol)-co-poly(ethylene brassylate-co-dioxanone) (PEG-EB-co-DO). CED of both free and encapsulated ATRIN-333 potently sensitized intracranial GBM tumors to low-dose (5 mg/kg) systemically-delivered lomustine, reducing tumor size and conferring a substantial survival benefit compared to cohorts treated with lomustine or the ATR inhibitor alone. The combination approach was well tolerated by the mice, with no hematological toxicity observed as assessed by bone marrow analysis and blood cell counts. Our results demonstrate that ATR inhibitor/lomustine combination therapy, used in conjunction with a CED platform, is a powerful avenue for GBM treatment and a viable option for potential clinical implementation. Note: AJ and TL contributed equally to this work.
Citation Format: Alexander Josowitz, Teresa Lee, Ranjini K. Sundaram, Jinal Pothupitiya, Eric J. Brown, Amrita Sule, Jason Beckta, Yongheng Wang, Joseph Vacca, Oren Gilad, Ranjit S. Bindra, W Mark Saltzman. Convection enhanced delivery of a novel ATR inhibitor synergizes with systemic lomustine for improved treatment of glioblastoma [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 7117.
Abstract 7118: FANCA promoteshomologous recombinationby facilitating DR-Loop formation
Authors: Li Fang , Yang Haibo , Gao Boya , Luo Liang , Zafar Alyan , Yuan Fenghua , Lan Li , Zhang Yanbin , Luo Liang , Zafar Alyan , Yuan Fenghua , Zhang Yanbin 
Published: March 2024

Abstract
Homologous recombination (HR), a fundamental DNA double-strand break (DSB) repair pathway, is a universal mechanism employed by cells to accurately mend breaks in both strands of the DNA helix, ensuring genomic stability. Displacement loops, commonly referred to as D-loops, play a crucial role as intermediate structures in HR. Furthermore, recent studies indicate that the unique DNA: RNA three-stranded structure, known as R-loops, may serve as a starting point for homologous pairing and contribute significantly to enhancing HR efficiency by promoting D-loop formation. Besides, the formation of R-loops might assist in recruiting DNA repair proteins, especially those related to HR, thereby accelerating the repair of damaged sites.In this study, we find that highly purified human FANCA protein anneals synthetic single-stranded RNA (ssRNA) and ssDNA species to R-loops and binds R-loop substrates with high affinity, preferring guanine-rich sequences in vitro. In comparison, FANCA exhibits both a weaker capacity to form D-loops and a lower affinity for binding to D-loops in vitro. We then use the DART (damage at RNA transcription site) system to reveal the colocalization of FANCA with R-loops in a highly transcribed genomic locus upon DNA damage in cells. Next, we further demonstrate FANCA's participation in forming R-loops in the initial DSB repair stage and assisting in removing R-loops later. Additionally, we uncover FANCA's ability to aid in the generation of R-loops at specific DNA DSB sites within transcriptionally active regions in both Tet-DR-GFP U2OS cells and DIvA (DSB inducible via AsiSI) cells. Importantly, the R-loop formation ability of FANCA is independent of the Fanconi Anemia (FA) pathway. In conclusion, our findings indicate that FANCA, independent of the FA pathway, can enhance HR in non-transcriptionally active DNA DSB sites through D-loop formation. Furthermore, FANCA significantly elevates transcription-Coupled Homologous Recombination (TC-HR) efficiency by catalyzing the formation of DNA: RNA hybrids, generating temporary R-loops at DNA damage sites and thereby contributing to genomic stability maintenance.
Citation Format: Fang Li, Haibo Yang, Boya Gao, Liang Luo, Alyan Zafar, Fenghua Yuan, Li Lan, Yanbin Zhang, Liang Luo, Alyan Zafar, Fenghua Yuan, Yanbin Zhang. FANCA promoteshomologous recombinationby facilitating DR-Loop formation [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 7118.
Abstract 7121: The novel WEE1i, APR-1051, is a potentially well tolerated and effective treatment for cyclin E-overexpressing cancers
Authors: Hansbarger Molly M. , Rocca Stephen J. , Ritzmann Sonia , Vacca Joseph , Tokiwa Bridget , Weinstein Jonathan , Zabierek Henry , Frye Justin , Carleton Michael , Brown Eric J. , Gilad Oren 
Published: March 2024

Abstract
Previous studies have demonstrated that WEE1 inhibitors (WEE1i) are a promising cancer therapeutic through synthetic lethality with Cyclin E overexpression. One challenge for two of the leading WEE1i, AZD1775 and ZN-c3, has been the observed off-targeting of PLK family members, namely, PLK1, PLK2 and PLK3. In addition, the therapeutic application of these inhibitors in clinical trials has been limited by adverse hematological effects, including anemia. Herein, we describe the testing of a novel WEE1i (APR-1051) that, based on preclinical studies: 1) demonstrates reduced off-targeting of PLK1, PLK2 and PLK3, and 2) has the ability to suppress the growth of CCNE1-overexpressing xenografted tumors while causing little impact on red blood cell and reticulocyte levels. APR-1051 has an IC50 of 2.2 nM for WEE1 in vitro and has shown the ability to limit the proliferation of various cancer cell lines in culture. Interestingly, the genotoxicity of APR-1051 is suppressed by increasing concentrations of PLK1 inhibitors, suggesting that off-targeting of PLK1 by other WEE1i may compromise efficacy of this targeted cancer treatment in addition to the risk of producing PLK1i-associated adverse effects. APR-1051 demonstrated effectiveness in suppressing the growth of Cyclin E-overexpressing breast and ovarian cancer cells lines, thus pinpointing Cyclin E as a potential biomarker for APR-1051 treatment. Importantly, dose and scheduling of APR-1051 that causes significant suppression of CCNE1-amplified high-grade serious ovarian cancer tumors in mice is well tolerated, with red blood cell and platelet counts remaining within non-pathogenic ranges after a 28-day treatment period. In addition, inhibition WEE1 by APR-1051 occurs at an IC50 that is 200-fold lower on average than the IC50 of hERG potassium channel inhibition, implying that APR-1051 will potentially exhibit low cardiotoxicity. APR-1051 is now progressing through IND-enabling studies. Together, these findings underscore the potential of APR-1051 as a novel WEE1i for the treatment of Cyclin E-overexpressing cancers.
Citation Format: Molly M. Hansbarger, Stephen J. Rocca, Sonia Ritzmann, Joseph Vacca, Bridget Tokiwa, Jonathan Weinstein, Henry Zabierek, Justin Frye, Michael Carleton, Eric J. Brown, Oren Gilad. The novel WEE1i, APR-1051, is a potentially well tolerated and effective treatment for cyclin E-overexpressing cancers [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 7121.
Abstract 7128: Novel Ku-DNA binding inhibitors impact on the cellular and in vivo DNA damage response to radio- and radiomimetic-therapy
Authors: Mendoza-Munoz Pamela L. , Chauhan Dineshsinha , Gavande Navnath S. , Dynlacht Joseph R. , Garrett Joy E. , Turchi John J. 
Published: March 2024

Abstract
DNA-PK, the DNA-dependent protein kinase, is a validated target for cancer therapeutics that plays a central role in the non-homologous end joining (NHEJ) DNA repair pathway and the DNA damage response (DDR). NHEJ is a key mechanism of DNA double-strand breaks (DSB) repair, especially those induced by ionizing radiation (IR). Ku 70/80 heterodimer is required as initiator in this process, acting as an essential DNA-binding component of DNA-PK that senses DNA damage. Blocking the DNA-PK kinase activity in combination with DSB inducing agents has been widely used as a therapeutic strategy to drive clinical efficacy of radiation therapy for cancer treatment.
We have reported a unique approach of DNA-PK inhibition by developing Ku-DNA binding inhibitors (Ku-DBi’s), small molecule inhibitors that target the interaction between Ku70/80 and DNA. Ku-DBi’s demonstrated a direct interaction with Ku70/80, a potent inhibition of Ku-DNA binding and DNA-PK catalytic activity, and in vitro and cellular NHEJ inhibitory activity. This results in the potentiation of non-small cell lung cancer (NSCLC) cellular sensitivity to DSB generating therapies, as a function of inhibiting DNA-PKcs autophosphorylation and dysregulation of signaling to the DDR. In this study, we have expanded our structure activity relationship analyses to focus on optimizing selectivity, cellular uptake and Ku inhibitory activity. The new series of Ku-DBi’s include oxindole derivatives of the X80 core structure that achieve these goals. These novel compounds display increased cellular uptake while retaining potent Ku inhibitory activity and enhanced cellular inhibition on DNA-DSB repair. Ku-DBi’s optimization has enabled in vivo analyses of Ku-DBi - ionizing radiation combination therapy in human xenograft models of non-small cell lung cancer. The impact of Ku-DBi treatment on therapeutic efficacy, toxicity, Ku/DNA-PK inhibition, and DDR signaling will be presented. These data represent a significant advance in the development of Ku-DNA binding inhibitors and their therapeutic intervention for cancer treatment.
Citation Format: Pamela L. Mendoza-Munoz, Dineshsinha Chauhan, Navnath S. Gavande, Joseph R. Dynlacht, Joy E. Garrett, John J. Turchi. Novel Ku-DNA binding inhibitors impact on the cellular and in vivo DNA damage response to radio- and radiomimetic-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 7128.
Abstract 7200: Non-cytotoxic inhibition of nuclear encoded mitochondrial protein MAGMAS resensitize treatment resistant prostate cancer cells to taxane therapy
Authors: Duran Alfonso , Whitley Kristen , Santiago Krystal , Mohammed Adil , Casiano Carlos , Das Bhaskar , Almaguel Frankis 
Published: March 2024

Abstract
Metastatic prostate cancer (PCa) is the leading cause of PCa-associated deaths and one of the leading causes of cancer mortality in men. Novel therapeutics, such as Prostate Specific Membrane Antigen (PSMA) ligand therapy, are emerging as effective treatment strategies for metastatic prostate cancer. However, most men succumb to Metastatic Castration Resistant Prostate Cancer (mCRPC) due to treatment resistance. MAGMAS, a 13.8 kDa mitochondrial protein, imports nuclear-encoded mitochondrial proteins into the mitochondrial matrix. MAGMAS is overexpressed in several aggressive tumors, such as breast cancer, glioblastoma, and prostate cancer. When overexpressed, MAGMAS plays a role as a cytoprotective protein by acting as a reactive oxygen species (ROS) scavenger that maintains sufficient ROS levels to promote cell proliferation but below the threshold levels that could lead to apoptosis. This study was designed to investigate the pro-survival and therapy-resistance functions of MAGMAS in treatment-resistant PCa cells. Predictively, we observed that the docetaxel (DTX)-resistant PC3-DR and DU145-DR PCa cell lines expressed significantly higher levels of MAGMAS compared to their drug-sensitive parental cell lines. We hypothesized that inhibiting Magmas reduces the aggressive properties of highly proliferative DTX-resistant metastatic PCa cell lines and re-sensitizes them to DTX. MAGMAS knockdown in DTX-resistant PC3 and DU145 cells in the presence of increasing DTX treatments enhanced sensitivity to DTX. Consistent with these results, pharmacological inhibition of MAGMAS with the novel BT#9 inhibitor in combination with increasing DTX concentrations also enhanced sensitivity to DTX in these cell lines. Additional studies using cell migration/invasion assays and tumor-sphere formation assays are underway to further establish MAGMAS as a potential therapeutic target to attenuate the aggressive properties of chemo-resistant PCa cells. Lastly, we will investigate the diagnostic potential of MAGMAS as a biomarker for advanced PCa and BT#9 as an imaging/therapeutic-specific agent for treatment-resistant tumors.
Citation Format: Alfonso Duran, Kristen Whitley, Krystal Santiago, Adil Mohammed, Carlos Casiano, Bhaskar Das, Frankis Almaguel. Non-cytotoxic inhibition of nuclear encoded mitochondrial protein MAGMAS resensitize treatment resistant prostate cancer cells to taxane 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 7200.
Abstract 7226: Synergy between ONC201 and temozolomide on ATF4 integrated stress response in glioblastoma
Authors: Chen Josephine , Roady Tyler J. , Zhou Lanlan , El-Deiry Wafik S. 
Published: March 2024

Abstract
Glioblastoma multiforme (GBM) is the most common primary brain tumor in adults, with a median survival of 15 months. The standard of care involves surgical resection followed by chemoradiotherapy. Even with the full course of treatment, GBM is uncurable, and patients eventually relapse. Although temozolomide (TMZ) is the first-choice chemotherapeutic for GBM, tumor drug resistance limits the effects of the treatment. There is a growing need for new therapies with enhanced efficacy on GBM tumors. Dordaviprone (ONC201) is a TNF-related apoptosis inducing ligand (TRAIL)-inducing compound that is increasingly being studied for GBM treatment. This imipridone small molecule induces apoptosis by activating the integrated stress response, which involves transcription factors ATF4 and CHOP. Subsequently, these transcription factors upregulate proapoptotic protein TRAIL and its receptor, Death Receptor 5 (DR5).
This study aims to investigate the combinatory effects of chemotherapeutics TMZ and ONC201 on GBM. Preliminary studies examined the cell viability of GBM cell line U251MG after dual treatment of 0 to 10uM of ONC201 and 0 to 200uM of TMZ using the CellTiter-Glo assay. Synergy was observed between the two drugs at higher concentrations of TMZ. This synergistic interaction was further characterized using western blots. When 0, 2, and 4uM of ONC201 were administered alone or in combination with 0, 60, and 120uM of TMZ, greater ATF4 expression was observed with the dual treatments than with the monotherapies. Subsequent western blots were conducted using three GBM cell lines (U251MG, T98G, and SNB19-GFP) at three time points (8, 24, and 48 hours). All cell lines were treated with 0 and 5uM of ONC201 alone or in combination with 0 and 200uM of TMZ. For all three cell lines, ATF4 expression increased in the combined presence of TMZ and ONC201. However, the effects of TMZ on ONC201-induced ATF4 expression were most pronounced in U251MG and least conclusive in T98G. Additionally, the time points in which this increase in ATF4 expression occurred varied among cell lines. CHOP expression was also probed and was seen to increase with the combination treatment in U251MG. These observations suggest a potential synergistic relationship between chemotherapeutics ONC201 and TMZ in the ATF4 integrated stress response pathway in GBM. By exploring the effects of this dual treatment on upstream and downstream factors in the pathway, we can identify, characterize, and potentially target the root cause of this synergy.
Citation Format: Josephine Chen, Tyler J. Roady, Lanlan Zhou, Wafik S. El-Deiry. Synergy between ONC201 and temozolomide on ATF4 integrated stress response in glioblastoma [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 7226.
Abstract 7255: Peptide-based siRNA delivery for tumor-specific targeting of lactate dehydrogenase C
Authors: Naik Adviti , Qasem Hanan , Decock Julie 
Published: March 2024

Abstract
Background: Breast cancer is the most common cancer worldwide and the leading cause of female cancer-related deaths, highlighting the pressing need for novel therapeutic interventions. Treatment of triple negative breast cancer in particular remains a challenge due to disease aggressiveness and the lack of durable treatment options. We speculate that targeting of Lactate Dehydrogenase C (LDHC) could be a novel approach given its highly tumor specific expression and immunogenic properties. We recently demonstrated that LDHC acts as a key regulator of the DNA damage response and tumor mitotic fidelity. Moreover, silencing of LDHC significantly improved treatment response to DNA damage response related anti-cancer drugs, highlighting its therapeutic potential for cancer precision medicine.
Methods: We characterized and evaluated several cell penetrating peptide-siRNA complexes for efficient silencing of LDHC in tumor cells using a 10R polyarginine peptide or bifunctional 10R-RGD, cRGD-10R or iRGD-10R peptides with tumor homing and penetrating abilities.
Results: Peptide-siRNA complex formation and tumor cellular uptake was confirmed using gel retardation assays and fluorescent confocal imaging. Biophysiochemical characterization and transmission electron microscopy revealed the complexes to be uniform in size with a low polydispersity index and positive zeta potentials. LDHC silencing in breast cancer cells using the peptide complexes demonstrated a 30-53% reduction in LDHC expression, with the 10R-siRNA and cRGD-10R-siRNA complexes showing the highest silencing efficiency. In 3D breast cancer spheroids, transfection with the 10R-siRNA complex resulted in a 20% downregulation of LDHC expression. Further analysis of the bifunctional-siRNA complexes in 3D cultures is ongoing as well as cytotoxicity analyses on non-cancerous cell lines.
Conclusions: Our findings demonstrate that peptide-mediated delivery of LDHC siRNA can reduce LDHC expression in 2D and 3D breast cancer cultures, suggesting that they could be used as a valuable approach for therapeutic intervention.
Citation Format: Adviti Naik, Hanan Qasem, Julie Decock. Peptide-based siRNA delivery for tumor-specific targeting of lactate dehydrogenase C [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 7255.