tbuckley/cabot-search huggingface dataset:
Abstract 4089: Investigating translesion synthesis DNA polymerases roles on tumor protection after temozolomide induced DNA damage
Authors: Marcela Teatin Latancia, André Uchimura Bastos, Natália Cestari Moreno, Davi Jardim, Clarissa RR Rocha, Carlos FM Menck
Journal: Cancer Research (2020)

Abstract Translesion DNA polymerases are capable of replicating damaged DNA, without removing the lesions, performing translesion synthesis (TLS), a mechanism of DNA damage tolerance. Tumor cells use this mechanism in order to survive lesions caused by chemotherapy and, therefore, this may be a strategy that tumor cells use to resist treatments. Moreover, it is an error-prone process and can lead to mutagenesis increasing resistance potential of tumor cells. Little is known about the role of TLS in Temozolomide (TMZ) tumor treatment. Our aim is to investigate how TMZ affects TLS mutated cells. Hence, we firstly treated primary fibroblasts cells lacking TLS mechanisms (XP-V) and analyzed cell proliferation by flow cytometry, cell viability by a colorimetric assay (XTT), for survival by apoptotic markers (such sub-G1) and clonogenic assays. In fact, XP-V cells are more sensitive to TMZ, indicating that TLS mechanisms are important to overcome DNA damage. TCGA data was also used to analyze TLS expression in glioblastoma patients. Curiously, in recurrently patients treated with TMZ, POLK expression was significantly increased. CRISPR/CAS9 knockout (KO) cells of glioblastoma cell lines, such as U251, were constructed for other TLS DNA polymerases enzymes genes, such as Pol Iota and Pol kappa. Gene KO was validated using Sanger sequencing and mutations resulted in stop codon. These pol iota and pol kappa KO cells had impaired viability after TMZ treatment. Moreover, genotoxic stress, as indicated by phosphorylated gH2AX, were increased in TMZ-treated cells. In summary, we can infer that TLS polymerases protect tumor cells from TMZ-induced DNA damage and thus, play important roles on overcoming resistance to this drug. As perspectives for this work, we intend to observe how replication is affected in these KO cells treated with TMZ by DNA Fiber Assays and measure DNA strand breaks in those cells by comet assay. Financial support: FAPESP, CNPq and CAPES. Citation Format: Marcela Teatin Latancia, André Uchimura Bastos, Natália Cestari Moreno, Davi Jardim, Clarissa RR Rocha, Carlos FM Menck. Investigating translesion synthesis DNA polymerases roles on tumor protection after temozolomide induced DNA damage [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 4089.
Abstract 963: Metabolic signatures of chemotherapy damage in mature T cells that lead to poor proliferation
Authors: Rajat K. Das, David M. Barrett
Journal: Cancer Research (2020)

Abstract We have previously described progressive T cell dysfunction (characterized by poor response to ex vivo stimulation) with cumulative chemotherapy exposure in pediatric patients. Chemotherapy appears to sensitize surviving T cells to activation induced cell death (AICD) with hallmarks of disordered metabolism, though the mechanism for each agent and the correct antidote varies. We used an in vitro model of chemotherapy exposure to identify signatures of damage in surviving T cells. T cells from healthy donors were exposed in vitro to doxorubicin, cytarabine and 4-hydroperoxycyclophosphamide (4-HPCP) and allowed to recover to assess the surviving cells as a model of the kinds of cells that are collected from pediatric patients for future adoptive cell therapies. T cells were assessed via the Agilent Seahorse platform for metabolic parameters including oxygen consumption (OCR), spare respiratory capacity (SRC) and glycolysis via extracellular acidification rate (ECAR). All classes of chemotherapy reduce OCR, whereas cytarabine reduces SRC. Doxorubicin increases ECAR and basal glycolysis. We analyzed the T cells via metabolites detected by mass spectrometry, which identified disordered glycolysis in doxorubicin treated cells, evidence of reactive oxygen species/glutathione in 4-HPCP and disordered polyamine synthesis with cytarabine. All classes inhibited T cell proliferation in response to CD3/28 stimulation, primarily due to AICD. We targeted each metabolic deficit with agents designed to support the metabolic pathways identified (2-deoxyglucose for doxorubicin, n-acetylcysteine for 4-HPCP and polyamine supplementation for cytarabine). Each agent was able to improve the proliferative response specific to the deficit, but there was no rescue across classes. We manufactured chimeric antigen receptor T cells (CART) from chemotherapy exposed T cells with and without rescue, and demonstrated improved cell recovery but not improved in vitro killing. Autologous T cells for adoptive cell therapy are currently collected after chemotherapy cycles in children, which may impact their suitability for CAR manufacture which requires ex vivo stimulation. Here we demonstrate each class of chemotherapy increases the susceptibility to AICD with a distinct metabolic hallmark in surviving cells. These metabolic pathways may be specifically targeted to reduce AICD during CAR manufacture, and thus potentially increase the yield from these patients. Citation Format: Rajat K. Das, David M. Barrett. Metabolic signatures of chemotherapy damage in mature T cells that lead to poor proliferation [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 963.
Proposed Requirements for Cardiovascular Imaging-Related Machine Learning Evaluation (PRIME): A Checklist
Authors: Partho P. Sengupta, Sirish Shrestha, Béatrice Berthon, Emmanuel Messas, Erwan Donal, Geoffrey H. Tison, James K. Min, Jan D’hooge, Jens-Uwe Voigt, Joel Dudley, Johan W. Verjans, Khader Shameer, Kipp Johnson, Lasse Lovstakken, Mahdi Tabassian, Marco Piccirilli, Mathieu Pernot, Naveena Yanamala, Nicolas Duchateau, Nobuyuki Kagiyama, Olivier Bernard, Piotr Slomka, Rahul Deo, Rima Arnaout
Journal: JACC. Cardiovascular imaging (2020)
Abstract 5857: Molecular characterization of response to interferon alpha in sensitive and resistant bladder cancer models
Authors: Robin Osterhout, Jennifer Green, Scott McDonnell, Amy Klova, Adeela Kamal
Journal: Cancer Research (2020)

Abstract Background: Over 70% of patients newly diagnosed with bladder cancer will present with non-muscle invasive disease (NMIBC). The standard of care treatment to prevent recurrence and progression is tumor resection followed by Bacillus Calmette-Guerin (BCG). While this treatment regimen is effective for many patients, a significant fraction become resistant over time. Adenoviral-delivered IFNα gene therapy is emerging as a safe and efficacious treatment for BCG-refractory NMIBC. IFNα is a type 1 interferon that mediates complex tumor-immune interactions, and also has direct cytotoxic effect on tumors. While the mechanisms of IFNα have been extensively studied, it is unclear which of these mechanisms are most relevant for driving therapeutic response. It is also poorly understood why some tumors are sensitive to the direct cytotoxic effects of IFNα and others are resistant. Methods: Here, we investigate the molecular mechanisms of tumor-intrinsic sensitivity and resistance to IFNα. We characterized response of a panel of bladder cancer cell lines to treatment with IFNα, and performed concomitant gene expression profiling to identify molecular features and pathways associated with response and sensitivity. These features were then compared across responsive and non-responsive cancer cell line models from other tissues of origin including skin, pancreas, liver and lung. Results/Conclusions: Several bladder cancer models exhibited a dose-dependent cytotoxic response to IFNα treatments, while others were resistant to these effects. Genomic and mRNA features associated with IFNα sensitivity/resistance were identified. Pan-cancer cell line analysis identified conserved and putative tissue-specific differences in IFNα downstream signaling genes in resistant vs sensitive cell lines. These features are being evaluated and will inform future investigation of the mechanism of IFNα anti-tumor activity in patients. Citation Format: Robin Osterhout, Jennifer Green, Scott McDonnell, Amy Klova, Adeela Kamal. Molecular characterization of response to interferon alpha in sensitive and resistant bladder cancer models [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 5857.
Abstract 2587: RAC1P29S expression in melanocytes is associated with increased DNA damage and altered cell cycle progression
Authors: Alexa C. Cannon, Jonathan Chernoff
Journal: Cancer Research (2020)

Abstract Melanoma is the fifth most common cancer in the United States that has less than a 25% 5-year survival rate once the cancer has metastasized beyond the lymph nodes. Recent exome studies of cutaneous melanoma have identified RAC1P29S as the third most prevalent hotspot mutation in 4-9% of sun-exposed melanoma. RAC1 alteration in cancer is correlated to poor prognosis, resistance to standard chemotherapy, and insensitivity to targeted inhibitors. As a member of the Ras superfamily of small GTPases, RAC1 functions as a master regulator of actin cytoskeleton dynamics and influences proliferation, cell migration, motility, and polarity. Although RAC1P29S mutations in melanoma and RAC1 alterations in several other cancers are becoming increasingly evident, the RAC1-driven biological mechanisms contributing to melanomagenesis remain elusive. Lack of rigorous signaling analysis has prevented identification of alternative therapeutic targets for RAC1P29S melanomas. To investigate the RAC1P29S-driven effect on downstream molecular signaling pathways, we generated an inducible RAC1P29S expression melanocytic cell line and performed RNA-sequencing (RNA-seq) coupled with multiplexed kinase inhibitor beads and mass spectrometry (MIBs/MS) to establish enriched pathways from the genomic to proteomic level. Our proteogenomic analysis has identified the G2-M cell cycle phase transition as a hyperactive pathway in RAC1P29S-expressing melanocytes. RAC1P29S expression promotes increased kinase activity of the PAK-PLK1-AURORA A axis and increased transition into M-phase as indicated by FACS analysis. Interestingly, RAC1P29S-expressing melanocytes also possess increased DNA damage via γH2AX foci, suggesting a compromise in G2-M checkpoint integrity and an altered DNA damage response. Here, we assess the influence of RAC1P29S on the PAK-PLK1-AURORA A axis and its role in promoting G2-M transition. In addition, we investigate the DNA damage response and cell cycle regulation in the presence of cytotoxic agents. Collectively, these results suggest novel therapeutic pathways to target in RAC1P29S-driven melanoma. Citation Format: Alexa C. Cannon, Jonathan Chernoff. RAC1P29S expression in melanocytes is associated with increased DNA damage and altered cell cycle progression [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 2587.
Abstract 6225: Addition of TRAIL receptor agonists after treatment with ONC201 or ONC212 converts pancreatic cancer cells from anti-proliferative to apoptotic <i>in vitro</i>
Authors: Aakash V. Jhaveri, Lanlan Zhou, Isacco Ferarrini, Young Lee, Wafik S. El-Deiry
Journal: Cancer Research (2020)

Abstract The 7% five-year survival rate for pancreatic cancer patients has remained unchanged for decades; the need for novel therapeutic interventions is imminent. ONC201 is the founding member of the impridone class, a class of orally bioavailable small molecules which show efficacy in multiple tumor types. ONC201 and ONC212, a fluorinated imipridone, have been shown to be potent inducers of the tumor necrosis factor related apoptosis inducing ligand (TRAIL) pathway. Both compounds are currently in clinical trials. In the context of pancreatic cancer, ONC201 and ONC212 induce either apoptotic or anti-proliferative effects. Additionally, both compounds activate the integrated stress response leading to DR5 upregulation in various cell types. We hypothesized that exogenous addition of TRAIL receptor agonists after pre-treatment with ONC201 or ONC212 could convert cells from anti-proliferative to apoptotic. Here, we examined both rhTRAIL and TLY012, a novel TRAIL receptor agonist with a substantially improved half-life. Pancreatic cancer cell lines were screened for synergy when treated with ONC201 or ONC212 for 72 hours followed by either rhTRAIL or TLY012 for 4 hours. Four cell lines (AsPC-1, BxPC3, Capan-1, and PANC-1) showed potent synergy with both rhTRAIL and TLY012. Growth inhibition was assessed through both Cell-Titer Glo and colony assays. Apoptotic synergy was determined using Cell-Titer Glo, western blots for PARP cleavage, and sub-G1 flow cytometric assays. Further analysis showed that ONC201 activates the integrated stress response and primes pancreatic cancer cells for TRAIL-induced apoptosis through regulation of key proteins. Upregulation of the integrated stress response and downregulation of XIAP, c-FLIP, and Bcl-XL was observed after treatment with ONC201 in BxPC3 and PANC-1 cell lines. The combination of ONC201 and TRAIL receptor agonists was non-toxic to human foreskin fibroblasts. Future experiments aim to examine G1 arrest after treatment with ONC201 and ONC212 via western blot and flow cytometry, to confirm surface expression of TRAIL and DR5 via flow cytometry, and to determine efficacy in pancreatic cancer xenografts. Taken together, these data indicate a novel therapeutic strategy for treatment of patients with ONC201 and ONC212 resistant pancreatic tumors. Citation Format: Aakash V. Jhaveri, Lanlan Zhou, Isacco Ferarrini, Young Lee, Wafik S. El-Deiry. Addition of TRAIL receptor agonists after treatment with ONC201 or ONC212 converts pancreatic cancer cells from anti-proliferative to apoptotic in vitro [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 6225.
Abstract 1906: Combination MEK and mTORC1/2 inhibition overcomes resistance to single agent therapy in pancreatic cancer
Authors: Wells Brown, Oksana Nemirovsky, Jordan Gillespie, Paul McDonald, Shoukat Dedhar
Journal: Cancer Research (2020)

Abstract Activating mutations in the KRAS oncogene are found in greater than 90% of pancreatic ductal adenocarcinoma (PDAC), yet KRAS remains difficult to inhibit pharmacologically. Small molecule inhibitors of RAF/MEK/ERK (MAPK) or mTOR are first line treatments for several human malignancies, however resistance to these targeted therapies continues to be a major clinical problem. We show in vitro dose dependent inhibition of proliferation and pERK1/2 in human PDAC cell lines and a KRAS-driven genetically engineered mouse model (GEMM) of pancreatic cancer in response to Trametinib, a small molecule MEK-inhibitor (MEKi). Similarly, Trametinib elicited a dose dependent inhibition of the in vivo tumor growth of a subcutaneous human PDAC xenograft, however these tumors rapidly developed resistance and contained areas of increased activation of pAkt(Ser473). We determined that genetic depletion of KRAS using doxycycline-inducible shRNA or small molecule MEKi leads to increased pAkt(Ser473) and activation of mTORC2 by western blot, implicating activation of the Akt/mTORC1/2 pathway may be a mechanism of resistance to MEKi. Interestingly, treatment of PDAC cell lines with Torin1, a small molecule inhibitor of mTORC1/2, results in the increased activation of pERK1/2, suggesting crosstalk and compensation of these two pathways as mechanisms of resistance. The combination of Trametinib and Torin1 leads to the inhibition of both pERK1/2 and pAkt(Ser473) that is accompanied by a dose dependent, synergistic increase in cytotoxicity not observed with either single agent. In human PDAC xenografts and a syngeneic GEMM, combination treatment of Trametinib and Torin1 dramatically reduced tumor burden and increased survival, without serious toxicity. These results demonstrate that combined inhibition of MEK/ERK and mTORC1/2 is a potent and viable therapeutic strategy for PDAC. Citation Format: Wells Brown, Oksana Nemirovsky, Jordan Gillespie, Paul McDonald, Shoukat Dedhar. Combination MEK and mTORC1/2 inhibition overcomes resistance to single agent therapy in pancreatic cancer [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 1906.
Abstract 3722: Extracellular arginine starvation imposes DNA replication fork stall and permits DNA damage tolerance
Authors: Yi-Chang Wang, Andrew A. Kelso, Yi-Hsuan Chen, Chi-An Hsieh, Wei-Kai Chen, Jeremy M. Stark, Hsing-Jien Kung, David K. Ann
Journal: Cancer Research (2020)

Abstract Regional nutrients deprivation, which is frequently encountered in many solid tumors due to poor vascularization, induces metabolic rewiring and genetic dysregulation to support the demands of proliferating cancer cells. Numerous chemotherapies exert their S-phase dependent cytotoxicity by producing deleterious effects on DNA to kill proliferating tumor cells. How regional nutrients deprivation affects the response of cancer cells to chemotherapy, especially DNA damaging genotoxicity, and what is the key nutrient dominates these effects is an active area of interest across tumor biology. Of all the amino acids we examined, only arginine is regional deprived in tumor core and indispensable for S-phase progression in multiple breast cancer cells and non-tumorigenic breast epithelial cells. We found that arginine deprivation stalls DNA replication in an mTORC1 inactivation, insufficient metabolites, or the integrated stress response pathway independent manner. We also found that low levels of newly synthesized Histone H4 marks (H4K5ac and H4K12ac), which were reported to be associated with adverse outcomes in various cancers including basal-like and HER2-positive breast cancer, are positively correlated with arginine bioavailability and could serve as surrogate markers of arginine sufficiency. Mechanistically, extracellular arginine is required for the translation of DNA-synthesis-dependent histone H4, but not H3, to promote DNA replication. Knockdown of arginyl-tRNA-transferase, like arginine deprivation, recapitulates the loss of histone H4 lysine 5 and 12 acetylation marks and compromises replication fork speed. Notably, one round of arginine deprivation and addition did not cause an increase in γH2AX, a hallmark of nuclear DNA double-stand breaks. However, multiple rounds of arginine fluctuation promotes the emergence of ATR-Chk1 checkpoint independent-nuclear p53-binding protein 1 bodies in the subsequent G1-phase of daughter cells and induces DNA damage tolerance and resistance to genotoxic agents. Thus, intratumoral variation in the arginine microenvironment synchronizes DNA replication with therapeutic response. Citation Format: Yi-Chang Wang, Andrew A. Kelso, Yi-Hsuan Chen, Chi-An Hsieh, Wei-Kai Chen, Jeremy M. Stark, Hsing-Jien Kung, David K. Ann. Extracellular arginine starvation imposes DNA replication fork stall and permits DNA damage tolerance [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 3722.
Abstract 2840: Development of a model of dihomo-gamma-linolenic acid interference with platelet promotion of ovarian cancer
Authors: Zitha Redempta Isingizwe, Doris M. Benbrook
Journal: Cancer Research (2020)

Abstract Background: Cancer is the second leading cause of deaths worldwide after cardiovascular diseases. A commonality between cancer and cardiovascular diseases is disregulation of platelets. Platelets and cancer are known to promote each other in a feedforward mechanism that is poorly understood. A long chain polyunsaturated fatty acids dihomo-gamma-linolenic acid (DGLA) was shown to reduce cardiovascular events in a platelet dependent manner while the exact mechanism of DGLA-mediated cancer cells death is yet to be explored. Objectives: The objective of our study was to develop an experimental model to study interventions that could disrupt the cancer/platelets loop. Methods: The effects of a range of DGLA concentrations on platelet aggregation and growth of high grade serous ovarian cancer cell lines (OVCAR3, MesOV, OVSAHO), normal human fallopian tube secretory epithelial cells (hFTSECs) primary culture and an immortalized hFTSEC cultures were determined with an MTT assay. Cocultures were used to evaluate effects of platelets on ovarian cancer cell line spheroid formation and size and effects of ovarian cancer cells and hFTSECs on platelet aggregation. Results: The minimal cytotoxic DGLA concentrations for cancer and normal epithelial cells were above physiologically-achievable concentrations, and the half maximal inhibitory concentrations (IC50's) were similar across epithelial cell types with the IC50's for hFTSEC primary culture (261 µM) and immortalized culture (206 µM) falling within the range of cancer cell IC50's (153-275 µM). DGLA inhibited platelet aggregation at concentrations ≥250 µM. Platelets increased cancer spheroid sizes in a concentration-dependent manner and cancer cells, but not hFTSECs, induced platelet aggregation in cocultures. Conclusions: Our model incorporates both platelet effects on cancer cells and cancer cell effects on platelets. Physiologically-achievable DGLA concentrations that affect platelet aggregation without affecting epithelial cells were identified. Minimal doses of DGLA needed to cause cytotoxicity against cancer and normal cells are above levels that are physiologically achievable. Future studies will utilize DGLA doses that can interfere with platelet aggregation without directly causing cytotoxicity to cancer or healthy cells. This experimental model will allow study of DGLA's potential for interfering with platelet promotion of ovarian cancer in the absence of direct effects of DGLA on cancer cells. Funded by NCI R01 CA196200 Citation Format: Zitha Redempta Isingizwe, Doris M. Benbrook. Development of a model of dihomo-gamma-linolenic acid interference with platelet promotion of ovarian cancer [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 2840.