bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 6954: Glycine decarboxylase regulates renal carcinoma progression and DNA damage response via interferon stimulated gene factor 3-mediated pathway
Authors: Kim Jin Young , Kim Byung Hoon , Choe Misun , Pham Thi Tuyet Mai , Kim Mikyung , Seo Ji Hae , Shin So Jin
Published: March 2024

Glycine decarboxylase (GLDC) is a mitochondrial enzyme of glycine cleavage system which catalyzes glycine to donate for one-carbon metabolism. It is implicated as a tumor suppressor in hepatocellular carcinoma but as an oncogene in lung cancer. Although GLDC expression in the kidney is second highest next to the liver, the role of GLDC in the kidney remains unclear. Thus, this study was designed to determine the role of GLDC in renal carcinoma. We found markedly increased expressions of GLDC in patients with renal cell carcinoma (RCC) classified as poor-risk group based on the Memorial Sloan Kettering Cancer Center prognostic model. In vitro studies revealed that cellular proliferation, colony formation was decreased in GLDC-deficient renal carcinoma cells. Additionally in vivo xenograft studies with GLDC-deficient and -overexpressing cells also revealed that tumor sizes were noticeably decreased in GLDC-deficient cell-injected mice while those were increased in GLDC-overexpressing cell-injected mice. Mechanistically, we found GLDC regulates renal carcinoma progression via interferon (IFN) stimulated gene factor 3 (ISGF3)-mediated pathway. Expressions of IRF9 and STAT2 were increased in GLDC-deficient cells while those were decreased in GLDC-overexpressing cells. Upon inducing expression of ISGF3 subunits, GLDC deletion elevated DNA damage, mitotic catastrophe, mitochondrial deficiency induced by chemotherapy. Finally, GLDC knockdown diminished pyrimidine synthesis to impair renal cancer progression. In summary, our finding reveals that GLDC regulates renal carcinoma progression and DNA damage response via ISFG3-medated pathway and lays a scientific foundation that could support a therapeutic strategy that targets GLDC for the treatment of renal carcinoma.

Citation Format: Jin Young Kim, Byung Hoon Kim, Misun Choe, Thi Tuyet Mai Pham, Mikyung Kim, Ji Hae Seo, So Jin Shin. Glycine decarboxylase regulates renal carcinoma progression and DNA damage response via interferon stimulated gene factor 3-mediated pathway [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 6954.
Abstract 696: Proton radiation and Seco-Duocarmycin SA: A synergistic strategy unveiling new frontiers in glioblastoma multiforme therapy
Authors: Morcos Ann , Bertucci Antonella , Fuller Ryan Nicholaus , Wall Nathan Robert , Vazquez Marcelo Eduardo
Published: March 2024

Glioblastoma multiforme (GBM) is one of the most aggressive brain cancers with a 6.9% five-year survival rate. More effective therapies are needed as standard treatments, which include surgery, radiation, and chemotherapy are inefficient due to radio-chemo-resistance and relapse. The goal of this project is to investigate the efficacy of seco-duocarmycin SA (sDSA) as an anticancer drug, alone and the potential synergy of combining proton radiation and sDSA in human GBM cell lines. Proton therapy offers numerous advantages in treating cancers because of its superior dose distribution and biological effects. sDSA is an exceptionally potent agent that selectively alkylates DNA at the N3 position of adenine, making it of great interest as a therapeutic drug. We hypothesize that by pairing sDSA with proton radiation, a more dynamic effect will result, which will amplify their collective power, unleashing an enhanced cytotoxicity against human GBM cells. GBM cell lines (T98G and LN18) were exposed to graded doses and concentrations of protons and sDSA respectively in order to evaluate cellular changes in proliferation, survival, cell cycle, apoptosis/necrosis induction, and DNA damage. Results show that proton radiation and sDSA when used alone induce a dose-dependent decrease of cell proliferation, an increase in foci formation, and an increase in G2/M phase arrest in LN18 and T98G cells. The data also illustrates that the combination of proton radiation and sDSA synergistically enhances these effects. The utilization of proton radiation in conjunction with sDSA against GBM represents an innovative and previously unexplored approach. Currently, the cellular mechanisms of sDSA cytotoxicity are not well understood or studied, and even less is known regarding the effects when combined with proton radiation. This study serves as a vital cornerstone in unraveling the biological response of GBM cells when confronted with proton radiation and sDSA, paving the way for the future development of a more precise and potent combination therapy.

Citation Format: Ann Morcos, Antonella Bertucci, Ryan Nicholaus Fuller, Nathan Robert Wall, Marcelo Eduardo Vazquez. Proton radiation and Seco-Duocarmycin SA: A synergistic strategy unveiling new frontiers in glioblastoma multiforme 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 696.
Abstract 7021: Selecting your epigenomic assay: Comparing ChIP-seq, CUT&RUN, and CUT&Tag
Authors: Guo Angela H. , Comeau Christopher R. , Chen Fang
Published: March 2024

For many years, chromatin immunoprecipitation (ChIP) was the standard assay for studying epigenetic mechanisms. However, two new versatile techniques have recently been developed that are faster, experimentally easier, and more cost-effective than ChIP. Cleavage Under Targets & Release Using Nuclease (CUT&RUN) and Cleavage Under Targets & Tagmentation (CUT&Tag) can be used for understanding protein-DNA interactions within the natural chromatin context of the cell. Both CUT&RUN and CUT&Tag can be combined with Next Generation Sequencing (NGS) to analyze the function of histone modifications and the binding of transcription factors, DNA replication factors, or DNA repair proteins across the genome.

CUT&RUN and CUT&Tag are rapid, robust, and true low cell number methods for the detection of protein-DNA interactions. Unlike ChIP, both assays are free of formaldehyde cross-linking, chromatin fragmentation, and immunoprecipitation. When compared to ChIP, CUT&RUN and CUT&Tag require fewer starting cells (as low as 5,000 – 20,000), are shorter assays (one day from cells to DNA), and generate lower background signal (requiring fewer sequencing reads). At Cell Signaling Technology (CST), we have developed ChIP-seq, CUT&RUN, and CUT&Tag assay kits and validated a broad set of antibodies against histone modifications, transcription factors, and cofactors that are compatible with these kits. This poster will discuss the fundamentals of all three assays and highlight important factors to consider when selecting an assay for your experiment.

Through our antibody validation efforts, we have also generated a unique and extensive archive of ChIP-seq, CUT&RUN, and CUT&Tag NGS data using recombinant, monoclonal antibodies. This allows for the controlled comparison of these three commonly used chromatin profiling techniques. In this poster, I will highlight the similarities and differences between these assays when mapping a variety of histone modifications, transcription factors, and cofactor binding events across multiple sample types.

Citation Format: Angela H. Guo, Christopher R. Comeau, Fang Chen. Selecting your epigenomic assay: Comparing ChIP-seq, CUT&RUN, and CUT&Tag [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 7021.
Abstract 7111: Homoharringtonine is effective in treating acute lymphoblastic leukaemia via WEE1 downregulation and inducing DNA damage
Authors: Sin Chun-fung , Yuen Kei-ching , Jiao Anan , Li Bai-lin , Yu Hau-wai
Published: March 2024

Acute lymphoblastic leukaemia (ALL) is an aggressive haematolymphoid malignancy that originated from clonal mutations in lymphoid precursors. The prognosis is poor in adult patients and relapse/refractory disease is not uncommon which carries dismal prognosis. There is an urgent need to develop novel therapeutics. Homoharringtonine (HHT) is a plant alkaloid which can bind to ribosomal A-site and thus inhibit protein synthesis. It was used to treat acute myeloid leukaemia in China during 1980s. Herein, we conducted a study to explore the therapeutic efficacy and mechanism of action in ALL. T-ALL (DND-41, PEER) and B-ALL (PALL-2, SUP-B15) cell lines were treated with HHT for 24 and 72 hours. Cell viability was reduced at a time and dose-dependent manner in all cell lines we tested, with increased in percentage of apoptosis. Western blot showed upregulation of p53, with PARP and caspase 3 cleavages upon treating with HHT for 24 hours. Moreover, we observed WEE1 downregulation which allowed cell cycle progression through G2/M with damaged DNA. Comet assay showed evidence of DNA damage. Proteomics study by label-free protein quantitation showed downregulation of proteins involving in homologous recombination-mediated DNA repairing machinery, including BRCA1 and RAD51. The findings not only showed therapeutic efficacy of HHT in ALL, but also demonstrated the first evidence of DNA damage induced by HHT which might account for its therapeutic effects. Further studies will be conducted for delineating the mechanisms of DNA damage and its relationship with therapeutic efficacy.

Citation Format: Chun-fung Sin, Kei-ching Yuen, Anan Jiao, Bai-lin Li, Hau-wai Yu. Homoharringtonine is effective in treating acute lymphoblastic leukaemia via WEE1 downregulation and inducing DNA damage [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 7111.
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

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

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

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

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

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

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

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

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.
Abstract 7273: Small molecule activation of PP2A in the treatment of melanoma
Authors: Johnson Hannah , Singh Amandeep , Raza Asif , Narayan Satya , Sharma Arun K.
Published: March 2024

Protein phosphatase 2A (PP2A) is a heterotrimeric holoenzyme functioning as a serine/threonine phosphatase, where it accounts for about 50-70% of all serine/threonine phosphorylation in the cell. Yet, PP2A is commonly inactivated in cancer, likely due to its role as a tumor suppressor. Due to the important role PP2A plays in many cellular processes, including those involved with tumor progression, there is a current need for novel therapeutics capable of targeting PP2A in cancer. Currently, none of the current PP2A modulators have made it into approved clinical use. As such, we have recently synthesized the PP2A activators, PPA24 and PPA27, using molecular docking and fragment-based drug design based on the structures of recently reported PP2A activators, iHAP1 and NSC49L. We were previously able to establish PPA24 as the lead compound in treating colorectal cancer (CRC) in vitro, compared to PPA27 and the parent compounds. Nevertheless, a single dose NCI-60 screen of both PPA24 and PPA27 indicated the cell selectivity present in both compounds and revealed the potential effect these compounds could have in other cancers. Further evaluation with an extended NCI-60 5-dose screen of PPA24 and PPA27 demonstrated a strong potential for both compounds in treating melanoma. Overall, the NCI-60 screen displayed PPA27 as most effective in melanoma across all cell lines screened, while PPA24 was found to be effective in both CRC and melanoma cell lines, agreeing with our previous findings. A cell viability screening of PPA24 and PPA27 in our laboratory across 5 melanoma cell lines (SK-MEL-2, SK-MEL-28, A375, Mel1241, and 451Lu) identified IC50 values in the range of 3.45-8.94 µM for PPA27 and 5.99-14.45 µM for PPA24. The parent compounds, iHAP1 and NSC49L, were also evaluated and NSC49L was found to be less effective in melanoma than previously found in CRC cells. Both PPA24 and PPA27 were found to be effective in cell lines with and without BRAFV600E mutation, though it appears the metastatic cell line, 451Lu, required an increased concentration for all compounds as compared to the IC50 values found in the other melanoma cell lines. Further evaluation revealed PPA24 and PPA27 as dose-dependently inducing apoptosis in cells with BRAFV600E (A375) and BRAF WT (SK-MEL-2). Together, these findings show the potential of PPA24 and PPA27 as therapeutic treatments for melanoma with or without BRAF mutations and are currently being further evaluated in several in vitro and in vivo melanoma models in our laboratory.

Citation Format: Hannah Johnson, Amandeep Singh, Asif Raza, Satya Narayan, Arun K. Sharma. Small molecule activation of PP2A in the treatment of 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 7273.
Abstract 7277: Discovery of INV-9956, an orally available and highly selective Cyp11A1 inhibitor for the treatment of castration-resistant prostate cancer with drug resistant AR mutations
Authors: Bai Chang , Chen Danqi , Xia Zilei , Huang Shujuan , Lin LIshan , Zeng Zhaopie , Su Jing , Sun Yongkui
Published: March 2024

Androgen Receptor (AR) signaling plays a profound role in prostate cancer and development. Efforts in harnessing androgen and AR axis for castration-resistant prostate cancer treatment have led to discovery of several therapeutics, including AR antagonists and Cyp17 inhibitors. However, resistance to these approved therapeutics has emerged, and remained a significant unmet medical need. Among the prominent resistance mechanisms of action are restored androgen signaling via AR amplification and overexpression, and gain-of-function mutations occurring at AR ligand binding domain that can be agonized by existing AR antagonists and/or non-androgenic steroids such as glucocorticoids. Targeting Cyp11A1 that catalyzes the formation of pregnenolone is effective to ablate biosynthesis of androgens and all steroids and thus holds promise to deliver coverage of a significant percentage of drug resistant AR mutations and benefit CRPC patients post treatment with AR antagonists or Cyp17 inhibitors. Here we present discovery and characterization of INV-9956, an orally available, selective, and potent Cyp11A1 inhibitor with well-acceptable pharmacokinetic properties. INV-9956 potently inhibits biosynthesis of pregnenolone and other androgens in H295R cells with IC50 at single-digit nanomolar, suppresses proliferation of prostate cancer cell lines harboring major clinically acquired drug resistant AR LBD mutations, such as AR L702H using coculture assays. Orally administered INV-9956 showed consistent dose dependent PK/PD correlations across animal species. Particularly, INV-9956 displayed pronounced tumor inhibition superior to known competitors in a CRPC VCaP xenograft model and in a “humanized” animal model. Furthermore, INV-9956 displayed a good tox profile in 14-day repeated dosing rat and dog studies, supported by a high selectivity to Cyp11A1 over other Cyp family members, clean hERG and mini-Ames, and no significant off-target activity in a safety panel screen. The promising preclinical profiles of INV-9956 lend strong support to its potentials in addressing unmet needs in CRPC treatments and warrant clinical development.

Citation Format: Chang Bai, Danqi Chen, Zilei Xia, Shujuan Huang, LIshan Lin, Zhaopie Zeng, Jing Su, Yongkui Sun. Discovery of INV-9956, an orally available and highly selective Cyp11A1 inhibitor for the treatment of castration-resistant prostate cancer with drug resistant AR 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 7277.
Abstract 7287: High-grade serous ovarian carcinoma detected with TP53 mutation panel and SiMSen-Seq
Authors: Widjaja Amanda Olsson , Micallef Peter , Ulfenborg Benjamin , Lycke Maria , Gyllensten Ulf , Carlsson Therese , Österlund Tobias , Ståhlberg Anders , Linder Anna , Sundfeldt Karin
Published: March 2024

Background: Ovarian carcinoma (OC) has the highest mortality among gynecologic malignancies due to absent or unspecific symptoms. The high-grade serous ovarian carcinoma (HGSC) accounts for over 60% of the OC associated deaths. The most frequent genetic aberrations in HGSC are mutations in the TP53 gene, detected in approximately 96% of the tumors. Previous studies have proposed potential diagnostic utility of detecting mutations in circulating tumor DNA (ctDNA) from OC patients. However, the need for diagnostic methods capable of detecting asymptomatic HGSC is unmet.

Objectives: The primary aims of this study were to design a screening tool for identification of HGSC and to evaluate the suitability of various clinical specimen types for diagnostic applications.

Methods: In this study, we designed a highly sensitive and robust screening tool using the simple, multiplexed, PCR-based barcoding of DNA for sensitive mutation detection using sequencing (SiMSen-Seq) technique for identification of HGSC (n=11) by TP53 mutation profile in various clinical specimen for diagnostic applications. Specimens sampled included primary tumors, ascites, plasma, vaginal samples, and both liquid and solid samples from cyst-, endocervical-, and endometrial origin (n=94).

Results: The in-house designed panel amplified 17 regions, encompassing 619 nucleotide positions within the TP53 gene. Pathogenic variants were identified in 10/11 of the primary tumors, with a VAF ≥ 9% (range: 9-91). Preliminary data indicated that all (100%) paired samples obtained corresponding somatic mutations between two or more of the different compartments from the same patient.

In total 10/10 ascites-, 16/16 cyst-, 8/8 plasma-, 5/8 vaginal-, 17/22 endocervical-, and 14/19 endometrial samples showed somatic variants at a consensus read depth of 3 and a minimum VAF ≥ 0.1%.

Conclusion: The present study suggests that the TP53 mutation panel can identify somatic variants in a variety of non-invasive liquid biopsies. Additionally, the assessment of the TP53 mutation panel exhibits potential for forthcoming clinical utilization as a diagnostic tool.

Citation Format: Amanda Olsson Widjaja, Peter Micallef, Benjamin Ulfenborg, Maria Lycke, Ulf Gyllensten, Therese Carlsson, Tobias Österlund, Anders Ståhlberg, Anna Linder, Karin Sundfeldt. High-grade serous ovarian carcinoma detected with TP53 mutation panel and SiMSen-Seq [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 7287.
Abstract 7293: Serum fusion gene transcripts to predict liver cancer
Authors: Luo Jian-Hua , Yu Yan-Ping , Liu Silvia , Geller David
Published: March 2024

Hepatocellular carcinoma (HCC) is the most common type of liver cancers and one of the most lethal malignancies for human. Early diagnosis of HCC is crucial in reducing the mortality of the disease. In this report, we analyzed a panel of 9 fusion transcripts in the serum samples from 136 individuals (61 HCC patients and 75 individuals without HCC) using TaqMan qRT-PCR. Our results showed that 7 fusion genes were frequently detected in the serum samples of HCC patients, including MAN2A1-FER (100%), SLC45A2-AMACR (62.3%), ZMPSTE24-ZMYM4 (62.3%), Pten-NOLC1 (57.4%), CCNH-C5orf30 (55.7%), STAMBPL1-FAS (26.2%) and PCMTD1-SNTG1 (16.4%). We then divided the samples into training and testing cohorts based on the sample collection time: 82 individuals with samples collected before 2016 as the training cohort while 54 individuals with sample collected after 2015 as the testing cohort. Machine learning models was constructed based on the combination of different fusion genes with various cutoffs to predict the occurrence of HCC in the training cohort using leave-one-out-cross-validation approach. One of the machine learning models called 4-fusion genes logistic regression model (MAN2A1-FER<40, CCNH-C5orf30<38, SLC45A2-AMACR<41, Pten-NOLC1<40) produced a 91.5% accuracy, with a sensitivity of 87.1% and specificity of 94.1% in the training cohort. The same model generated an accuracy of 83.3%, with a sensitivity of 73.3% and specificity of 95.8% in testing cohort. When the training and testing cohorts were combined, the model produced an accuracy of 86%. When serum α-fetal protein (AFP) level was incorporated into the machine learning model, we found a 2-fusion gene+AFP logistic regression model (MAN2A1-FER<40, CCNH-C5orf30<38, AFP) generated an accuracy of 94.8% in the training cohort with a sensitivity of 93.5% and specificity of 96.3%. The same model generated 95% accuracy in both the testing cohort and the combined cohorts in the validation. Cancer treatment reduced most of the serum fusion transcript levels, reflecting the reduction of the tumor load. As a result, serum fusion gene machine learning models may serve as important tools in screening HCC and monitoring the impact of HCC treatment.

Citation Format: Jian-Hua Luo, Yan-Ping Yu, Silvia Liu, David Geller. Serum fusion gene transcripts to predict liver 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 7293.
Abstract 7297: Inhibition of lung tumorigenesis and potentiation of cancer preventive vaccines by a small molecule CA170 targeting the immune checkpoint protein VISTA
Authors: Zhang Qi , Pan Jing , Xiong Donghai , Wang Yian , Miller Mark S. , You Ming
Published: March 2024

The V-domain Ig Suppressor of T cell Activation (VISTA) is expressed on cells of the myeloid and lymphoid lineages and is an emerging target for cancer immunotherapy. Blocking VISTA activates both innate and adaptive immunity to eradicate tumors in mice. Furthermore, a tripeptide small molecule antagonist of VISTA, CA170, exhibited potent anticancer efficacy on carcinogen-induced mouse lung tumorigenesis. We have previously demonstrated that KRAS or EGFR vaccines are effective in preventing lung tumorigenesis driven by either KRAS or EGFR in a pure prevention setting but are less effective in mice carrying existing lesions. Here, we determined if combining an MHC class II-restricted multi-antigen vaccine targeting KRAS or EGFR with CA170 will provide enhanced efficacy in preventing lung cancer progression. Using tetracycline-inducible KRAS and EGFR transgenic mice, we found that lung tumor development was significantly suppressed when CA170, delivered by aerosol inhalation to minimize systemic toxicity, was combined with either KRAS or EGFR MHCII-directed peptide vaccines using a post-initiation model. Flow cytometry and single-cell RNA sequencing (scRNA-seq) revealed that CA170 significantly increases tumor infiltrating CD8+ T cells and enhances effector-memory T cell frequencies and functions of both CD4+ and CD8+ T cells. These changes coincide with significant reductions in G-MDSCs (granulocytic myeloid-derived suppressor cells) and Foxp3+ Treg populations within lung tumors from mice treated with CA170. We found that the KRAS and EGFR preventive vaccines primarily induced the expansion of CD4+ effector T cells. VISTA antagonism by CA170 revealed strong efficacy against lung tumorigenesis with broad immunoregulatory functions that influence effector, memory, and regulatory T cells, and drive an adaptive T cell tumor-specific immune response that enhances the efficacy of the KRAS and EGFR preventive vaccines in transgenic mouse models of lung cancer.

Citation Format: Qi Zhang, Jing Pan, Donghai Xiong, Yian Wang, Mark S. Miller, Ming You. Inhibition of lung tumorigenesis and potentiation of cancer preventive vaccines by a small molecule CA170 targeting the immune checkpoint protein VISTA [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 7297.