bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract 1055: Novel and highly potent ATR inhibitor M4344 kills cancer cells with replication stress and enhances the chemotherapeutic activity of widely used DNA damaging agents
Authors: Jo Ukhyun , Senatorov Ilya , Zimmermann Astrid , Saha Liton Kumar , Murai Yasuhisa , Kim Se Hyun , Rajapakse Vinodh N , Elloumi Fathi , Takahashi Nobuyuki , Schultz Christopher , Thomas Anish , Zenke Frank , Pommier Yves 
Published: July 2021

Abstract
Purpose: Although several ATR inhibitors are in development, there are unresolved questions regarding their differential potency, molecular signatures of cancer patients for predicting activity and most effective therapeutic combinations. Here, we elucidate how to improve ATR-based chemotherapy with the newly developed ATR inhibitor, M4344 using in vitro and in vivo models.
Experimental design: The potency of M4344 was compared with the clinically developed ATR inhibitors BAY1895344, berzosertib, and ceralasertib. The anticancer activity of M4344 was investigated as monotherapy and combination with clinical DNA damaging agents in multiple cancer cell lines, patient-derived tumor organoids and mouse xenograft models. We also elucidated the anticancer mechanisms and potential biomarkers for M4344.
Results: M4344 is highly potent among the clinically developed ATR inhibitors. Replication stress (RepStress) and neuroendocrine (NE) gene expression signatures are significantly associated with a response to M4344 treatment. M4344 kills cancer cells by inducing cellular catastrophe and DNA damage. M4344 is highly synergistic with a broad range of DNA-targeting anticancer agents. It significantly synergizes with topotecan and irinotecan in patient-derived tumor organoids and xenograft models.
Conclusions: M4344 is a promising and highly potent ATR inhibitor. It enhances the activity of clinical DNA damaging agents commonly used in cancer treatment including topoisomerase inhibitors, gemcitabine, cisplatin and talazoparib. RepStress and NE gene expression signatures can be exploited as predictive markers for M4344.
Citation Format: Ukhyun Jo, Ilya Senatorov, Astrid Zimmermann, Liton Kumar Saha, Yasuhisa Murai, Se Hyun Kim, Vinodh N Rajapakse, Fathi Elloumi, Nobuyuki Takahashi, Christopher Schultz, Anish Thomas, Frank Zenke, Yves Pommier. Novel and highly potent ATR inhibitor M4344 kills cancer cells with replication stress and enhances the chemotherapeutic activity of widely used DNA damaging agents [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1055.
Abstract 1059: Combination of gemcitabine and cytidine deaminase inhibitor: A breakthrough cocktail for the treatment of pancreatic ductal adenocarcinoma
Authors: Patki Manali , Saraswat Aishwarya , Bhutkar Shraddha , Dukhande Vikas , Patel Ketankumar 
Published: July 2021

Abstract
Pancreatic ductal adenocarcinoma is a very common type of pancreatic cancer and is one of the deadliest cancers. Gemcitabine (Gem), is still the mainstay drug for the treatment of PDAC. Gem is a hydrophilic drug which requires nucleoside transporters for its efficient uptake. Once inside the cell, Gem is converted to an active triphosphate form which inhibits DNA synthesis and causes apoptosis. However, Gem gets inactivated by cytidine deaminase (CDA). Long term treatment with Gem leads to increased CDA production thereby developing resistance. We hypothesize that combination of Gem with CDA inhibitor like Zebularine (Zeb), could prevent the intracellular degradation of Gem. Combination can potentially result in enhancing the anti-cancer activity of Gem, reduced dose and dosing frequency and minimizing side effects. The objectives of our study were; (a) to investigate the cytotoxic interaction of Gem and Zeb alone and in combination (b) Evaluating effect of various apoptosis and proliferation markers using flow cytometry and western blot assay. Initially we explored the anti-proliferative effects of Gem and Zeb as a single drug and in combination on MiaPaca-2 cells using MTT assay. Combination index was calculated using chou talalay method and Combenefit software. Effect of Gem, Zeb, and combination treatment on the cell viability of 3D tumor spheroids and its area was carried out using fluorescence microscopy and ImageJ software respectively. Apoptosis study was carried out using Annexin V apoptosis kit.Gem and Zeb exhibited dose-dependent inhibition in viability of MiaPaca-2 cells with an IC50 of 0.48 and 67.82 µM, respectively. The combination index of 0.09 suggest “very strong synergism” (Table 1). 3D spheroid treated with combination exhibited a highly distorted surface with significantly higher number of dead cells. Our research confirms that this synergistic combination can be a breakthrough approach for the treatment of PDAC.
Table 1.IC50 of Gem, Zeb and combination of Gem+Zeb in Miapaca2 cellsDrugMolar RatioIC50 of GemIC50 of ZebCombination IndexSingle-0.4867.82Gem1:100.0440.40.09
Citation Format: Manali Patki, Aishwarya Saraswat, Shraddha Bhutkar, Vikas Dukhande, Ketankumar Patel. Combination of gemcitabine and cytidine deaminase inhibitor: A breakthrough cocktail for the treatment of pancreatic ductal adenocarcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1059.
Abstract 1065: Concomitant dexamethasone treatment and tumor treating fields induced cell death in glioblastoma
Authors: Schiesl Abigail , Linder Benedikt , Rödel Franz , Hehlgans Stephanie , Güllülü Ömer , Seifert Volker , Koegel Donat , Senft Christian , Dubinski Daniel 
Published: July 2021

Abstract
Objective: Patients suffering from Glioblastoma (GBM) usually present with perilesional edema which is the major contributor of neurologic deficit. Dexamethasone (Dex) has become the corticoid of choice due to its fast and effective alleviation of perilesional edema. The impact of concomitant Dex treatment on TTFields efficacy is unexplored to date.
Methods: Human GBM cell lines MZ54 and U251 were treated with TTF in combination with Dex and the effects on cell counts and cell death were determined via flow cytometry. We furthermore investigated the influence of Dex on the cell cycle distribution/cell cycle arrest with and without double thymidine block for synchronisation via flow cytometry in both cell lines.
Results: TTF treatment (200 kHz/250 kHz) for 72 h was able to induce massive cell death (70 %) in the cultures of both cell lines. Cell cycle analysis performed after synchronization showed that Dex treatment (65 µM/165 µM) evoked an accumulation of both cell lines in the G0/G1 phase. Concurrent Dex treatment had no significant influence on the extent of apoptosis induced by TTFields.
Conclusions: Despite the partial G0/G1 arrest induced by Dex, our results show no interference of Dex with the antitumorous capacity of TTF in vitro. These data support the hypothesis that concomitant therapy with Dex does not negatively interfere with TTF efficacy in primary GBM.
Citation Format: Abigail Schiesl, Benedikt Linder, Franz Rödel, Stephanie Hehlgans, Ömer Güllülü, Volker Seifert, Donat Koegel, Christian Senft, Daniel Dubinski. Concomitant dexamethasone treatment and tumor treating fields induced cell death in glioblastoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1065.
Abstract 1071: Studying the ability of retinoids to inhibit growth of CRC cells based on their retinoid pathway genotype
Authors: Hunsu Victoria O. , Facey Caroline O. , Opdenaker Lynn M. , Boman Bruce M. 
Published: July 2021

Abstract
Colorectal cancer (CRC) tumorigenesis arises through acquisition of mutations in a colonic stem cell (SC) that transforms it into a cancer stem cell (CSC). There are no curative treatments for advanced CRC because CSCs appear to be resistant to chemotherapy and/or radiation. Because all-trans retinoic acid (ATRA) is a highly effective and often curative treatment for acute promyelocytic leukemia patients, we conjecture that retinoids may be an efficacious treatment for CRC. Retinoic acid (RA) is a metabolite of vitamin A which is known to induce differentiation of SCs and inhibit cell proliferation. Our goal is to discover how to therapeutically target human CRC CSCs using the differentiation-inducing effects of retinoid agents. Our previous study on the RA metabolizing enzyme aldehyde dehydrogenase (ALDH) shows that ALDH marks normal and malignant colonic SCs and that RA signaling mainly occurs through colonic ALDH+ SCs. Hypothesis: The ability of retinoid agents, ATRA, 9-cis retinoic acid, 13-cis retinoic acid and Liarozole, to induce differentiation of CSCs depends on the RA pathway genotype according to mutations in RA signaling components in CRC cells. Indeed, our bioinformatics analysis shows that many RA pathway genes are overexpressed and often mutated in CRC. We have also evaluated the ability of the different RA ligands to inhibit cell growth and induce differentiation using a panel of CRC cell lines that have specific RA signaling mutations. Further investigation of RA signaling mechanisms that regulate colon SCs and how dysregulation contributes to the SC overpopulation that drives CRC growth should provide insight into strategies for designing new SC-targeted therapies for CRC.
Citation Format: Victoria O. Hunsu, Caroline O. Facey, Lynn M. Opdenaker, Bruce M. Boman. Studying the ability of retinoids to inhibit growth of CRC cells based on their retinoid pathway genotype [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1071.
Abstract 1079: A synthetic lethal strategy using PARP and ATM inhibition for overcoming trastuzumab-resistance in HER2-positive cancers
Authors: Oh Kyoung-Seok , Nam Ah-Rong , Bang Ju-Hee , Seo Hye-Rim , Kim Jae-Min , Yoon Jeesun , Kim Tae-Yong , Oh Do-Youn 
Published: July 2021

Abstract
Background: DNA damage response (DDR) pathway is essential for maintaining genomic stability, cell survival, and tumorigenesis. However, the roles of DDR pathway in HER2-positive tumors remain unclear. This study aims to discover the function of DDR in trastuzumab-resistant (TR) cells to better understand HER2-biology and to suggest novel treatment strategy using DDR-targeting agents in HER2-positive TR tumors.
Methods: Four HER2-positive TR cell lines (NCI-N87TR, SNU-216TR, SNU-2670TR, and SNU-2773TR) and their corresponding parental cells (NCI-N87, SNU-216, SNU-2670, and SNU-2773) were subject to immunoblotting to identify expression profiles of DDR proteins. Proteasome inhibitor MG-132 and cycloheximide chase assay were used for understanding PARP1 dynamics in TR cells. MTT assay and colony-forming assay were performed to evaluate antiproliferative effect of PARP inhibitor (PARPi, olaparib), ATM inhibitor (ATMi, AZD0156) and ATR inhibitor (ATRi, Ceralasertib). DNA damage and homologous recombination repair (HRR) efficiency were measured by comet assay and immunofluorescence respectively. Cell cycle analysis using flow cytometry was performed to assess drug-induced apoptosis.
Results: Increase of PARP1 expression was observed in all four TR cells. Decreased proteasomal degradation of PARP1 was found in TR cells compared to parental cells. Olaparib showed better anti-proliferative effect in TR cells compared to parental cells. After treating with olaparib, there was a defect in formation of Rad51 foci, instead, there was induction of phosphorylation of ATM and ATR in TR cells, which might attenuate the effects of olaparib in TR cells. Combination of olaparib with AZD0156 showed stronger anti-tumor effect than olaparib monotherapy in TR cells. Moreover, synthetic lethal interaction was observed by olaparib/AZD0156 combination in TR cells. Interestingly, this synthetic lethal interaction was exclusively occurred in TR cells not in parental cells. Even though olaparib and ceralasertib combination showed better anti-tumor effect than each single drug in some TR cells, synthetic lethal interaction was not observed by olaparib/ceralasertib combination in TR cells.
Conclusion: Dual inhibition of PARP1 and ATM could be a good strategy to overcome the resistance to trastuzumab in HER2-positive cancers using its synthetic lethal interaction.
Citation Format: Kyoung-Seok Oh, Ah-Rong Nam, Ju-Hee Bang, Hye-Rim Seo, Jae-Min Kim, Jeesun Yoon, Tae-Yong Kim, Do-Youn Oh. A synthetic lethal strategy using PARP and ATM inhibition for overcoming trastuzumab-resistance in HER2-positive cancers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1079.
Abstract 1085: PD-L1-mediated resistance to chemotherapy is overcome by an irreversible JNK inhibitor in colorectal cancer cells
Authors: Sinicrope Frank A. , Sun Lei , Patai Arpad , Hogenson Tara L. , Fernandez-Zapico Martin E. , Qin Bo 
Published: July 2021

Abstract
Background Colorectal cancers (CRCs) are intrinsically drug resistant tumors with frequent low or absent tumor cell PD-L1 expression. Previously, we reported that PD-L1 depletion in CRC cells can confer chemoresistance. Given that JNK signaling has been implicated in cell survival and drug resistance in CRC cells, we examined the role of JNK and its regulation in chemoresistance in CRC cells with loss of PD-L1.
Materials & MethodsHuman CRC cell lines (RKO, DLD1 and HCT15) were utilized and parental and PD-L1 knockout/knockdown cells were generated. Cells were treated with a JNK1-3 inhibitor (JNK-IN-8) alone or combined with a MEK1/2 inhibitor (cobimetinib), CPT-11 or oxaliplatin. Protein/protein interaction was analyzed by immunoprecipitation (IP); protein/RNA interaction was analyzed by RNA IP assay. RNA level and half life were measured by QRT-PCR. Apoptosis was measured by cleaved caspase-3 and quantified by Annexin V labeling using FACS. Colony formation assay was performed.
ResultsPD-L1 depletion in CRC cells was shown to enhance JNK activity that was due to reduced mRNA stability of the upstream CYLD deubiquitinase. Since PD-L1 competes with the ribonuclease EXOSC10 for binding to CYLD mRNA, loss of PD-L1 increases the interaction of EXOSC10 and CYLD mRNA resulting in its ribonuclease-mediated degradation and activation of JNK signaling. JNK activation increased BIM phosphorylation at Thr116 that promotes its sequestration by MCL-1 and BCL-2. Notably, a selective and irreversible JNK1-3 inhibitor (JNK-IN-8) reduces BIMThr116 phosphorylation and can release BIM from its sequestration by MCL-1 and BCL-2 to promote apoptosis. Furthermore, use of JNK-IN-8, an MCL-1 antagonist (AZD5991), or their combination in tumor cells lacking PD-L1 is shown to promote apoptosis and reduce long-term clonogenic survival induced by multiple anti-cancer drugs. As confirmation, knockdown of PD-L1 can confer drug resistance in a human colon cancer-derived organoid model that can be reversed by JNK-IN-8.
Conclusion Tumor cells with low or absent PD-L1 expression show increased JNK activity that promotes BIM sequestration by MCL-1/BCL-2 to confer multiple drug resistance that can be reversed by a JNK inhibitor.
Citation Format: Frank A. Sinicrope, Lei Sun, Arpad Patai, Tara L. Hogenson, Martin E. Fernandez-Zapico, Bo Qin. PD-L1-mediated resistance to chemotherapy is overcome by an irreversible JNK inhibitor in colorectal cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1085.
Abstract 1135: Antitumor activity of novel reversible LSD1 inhibitors in preclinical models of AML and SCLC
Authors: Byun Joo-Yun , Lee Won Jong , Kim Won jung , Kim Minjeong , Bae Inhwan , Hong Seokhyun , Kim Yu-Yon , Park Hyunjin , Kim Eunyoung , Kim Young Hoon , Ahn Young Gil , Suh Kwee Hyun 
Published: July 2021

Abstract
Lysine-specific demethylase 1 (LSD1) has become a biologically important and validated epigenetic target for cancer therapy since its identification in 2004. LSD1 mediates many cellular signaling pathways and is involved in the initiation and development of cancers. Aberrant overexpression of LSD1 has been observed in different types of cancers, and such epigenetic dysregulation plays a critical role in pathogenesis of various types of cancers such as acute myeloid leukemia (AML) or small cell lung cancer (SCLC). In this study, we introduce HM97346 and its derivatives as novel LSD1 inhibitors, and report a therapeutic potential for AML and SCLC patients based on several preclinical characterization and assessment. HM97346 and its derivatives were designed and synthesized as novel reversible inhibitors of LSD1. Standard cell proliferation assay, immunoblotting, biomarker expression, and apoptosis analysis were carried out to validate their potency in vitro studies using different AML and SCLC cell lines. The in vivo antitumor activity was evaluated in AML and SCLC cell xenograft mouse models. Tumor sizes were measured and tumor samples were analyzed to define the mechanisms of action. HM97346 and its derivatives showed strong inhibition on LSD1 enzymatic activity in biochemical assay and promoted the methylations of histone H3 lysine 4 (H3K4) in both SCLC and AML cells. They reduced the expression of neuroendocrine factors ASCL1 in SCLC cells, effectively and dose-dependently. Moreover, in human AML cell lines, they stimulated cellular differentiation by disrupting LSD1-GFI1 complex and induced transcription factor PU.1 as well as myeloid differentiation markers CD86 and CD11b. As a result, they significantly inhibited cellular proliferation and induced apoptosis in studies using AML and SCLC cells. Oral administration of HM97346 and its derivatives inhibited tumor growth in human AML and SCLC cell xenograft mouse models studies. These antitumor effects dramatically increased in combination with standard chemotherapies. In conclusion, HM97346 and its derivatives, new synthesized reversible LSD1 inhibitors, showed potential anticancer activity in preclinical AML and SCLC models. Moreover, these compounds could provide a new insight and possibility in cancer therapy through epigenetic modulation as not only monotherapy but also combination therapy.
Citation Format: Joo-Yun Byun, Won Jong Lee, Won jung Kim, Minjeong Kim, Inhwan Bae, Seokhyun Hong, Yu-Yon Kim, Hyunjin Park, Eunyoung Kim, Young Hoon Kim, Young Gil Ahn, Kwee Hyun Suh. Antitumor activity of novel reversible LSD1 inhibitors in preclinical models of AML and SCLC [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1135.
Abstract 1162: Monitoring COVID-19 RNA methyltransferases activities for developing therapeutic drugs
Authors: Goueli Said A. , Hsiao Kevin 
Published: July 2021

Abstract
The recent pandemic outbreak of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-Cov-2) was first reported in Wuhan, China in late 2019 resulting in infection of over 20 million and death of over one million world-wide as of October 2020. The infection by this virus is highly transmissible and can lead to severe pneumonia and death. The SARS-CoV-2 is an enveloped virus and belongs to the beta coronavirus family containing a large and complex positive-sense single stranded RNA genome (~30kb).It binds to human ACE2 receptor with high affinity, compared to the other CoVs, via its spike protein (S) and membrane fusion leading to the release of its genomic RNA that replicates and produce higher number of subgenomic RNAs. The viral RNA is then capped by nsp 14 and nsp10/16, two nonstructural proteins that catalyze the methylation of RNA to limit its degradation by cellular 5'-3'exonuclease and evade host immune system. These enzymes play critical role in translation of the viral RNA and its replication and thus leading to viral survival. We have used a bioluminescent high throughput enzyme assay for monitoring the activity of these enzymes in order to develop novel inhibitors which can be advanced for therapeutic treatment. We show that we can determine the activity of nanogram amounts of these enzymes and test the activity of these enzymes using different inhibitors, some of which are competitive with S-adenosyl methionine the canonical substrate for these enzymes. We also show the effect of inhibitors that compete with the oligonucleotide substrate. Finally, we tested the effect of a peptide modulator of COVID-2 on the activity of both nsp10/16 and nsp14. The assay is simple, homogenous, fast, and bioluminescent which provides a very robust platform for testing novel compounds on the viral methyltransferases leading to the generation of new drugs towards inhibiting the replication of COVID19
Citation Format: Said A. Goueli, Kevin Hsiao. Monitoring COVID-19 RNA methyltransferases activities for developing therapeutic drugs [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1162.
Abstract 1163: Histone deacetylase inhibitors as potential differentiation therapy in lung adenocarcinoma
Authors: Chong Wai Chin , Vaghjiani Vijesh , Cain Jason Edward 
Published: July 2021

Abstract
Impaired differentiation is a common feature of cancer. In contrast to chemotherapy, the goal of differentiation therapy is to exhaust the malignant potential of tumour cells through the reactivation of developmental programs rather than cell death. The Switch/Sucrose Non-Fermentable (SWI/SNF) DNA remodelling complexes play a vital role in regulating cellular differentiation and have been strongly implicated in cancer. SWI/SNF complexes bind to the DNA-histone scaffold and initiate transcription via the recruitment of vital cellular transcriptional machinery including histone acetyltransferases. Next-generation sequencing has identified mutations in at least 10 genes encoding subunits of the SWI/SNF complexes that are recurrently mutated in cancers originating in nearly every body tissue, collectively occurring in &gt;25% of all human malignancies. Lung adenocarcinoma (LAC) accounts for &gt;40% of all lung cancers and has an 18% of overall 5-year survival. Mutations in SMARCA4 are believed to occur in &gt;12% of LAC.
Using a panel of characterized human LAC cell lines we show a marked sensitivity of the HDACi, HDACi, exclusively to SMARCA4-null LAC only. This is preceded by increased H3K27ac, decreased H3K27me3 and decreased EZH2 expression. Sustained low-dose panobinostat treatment of SMARCA4-mutant LAC cell lines, results in unique gene expression changes consistent with differentiation, not observed in SMARCA4 wildtype lines. To further demonstrate the specific dependence of loss of SMARCA4 on response to HDACi, we generated three isogenic cell lines using CRISPR KO. H358, H441 and H2009 SMARCA4 KO LAC cell lines were markedly more sensitive to panobinostat than their wildtype parental lines. Lastly, panobinostat treatment results in tumour growth arrest and increased survival in SMARCA4-deficient LAC cell line xenografts and PDX models in vivo but not in SMARCA4-intact LAC models. Together, these data suggest that SMARCA4-deficient LAC are dependent on HDAC activity to maintain an undifferentiated state and are therefore highly susceptible to epigenetic differentiation therapy.
Citation Format: Wai Chin Chong, Vijesh Vaghjiani, Jason Edward Cain. Histone deacetylase inhibitors as potential differentiation therapy in lung adenocarcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1163.