bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract PO-009: Targeting a unique electrochemical vulnerability in a pediatric brain tumor to potentiate proton beam radiotherapy
Authors: Krummel Daniel Pomeranz , Kallay Laura , Bhattacharya Debanjan , Gawali Vaibhavkumar , Donatien Kamdem T. , Ahmed Taukir , Cook James M. , Lamba Michael , Wells Susanne , Vatner Ralph E. , Sertorio Mathieu , Ionascu Dan T. , Sengupta Soma 
Published: April 2021

Abstract
Medulloblastoma (MB) is the most common malignant (WHO Grade IV) primary brain cancer in children, adolescents, and young adults. Radiotherapy (RT) is a mainstay of MB treatment, as it is for most childhood and adult cancers. RT dose and frequency needed to achieve efficacy in MB patients severely impacts survival outcomes and is the cause of long-term cognitive deficits. To improve on short-term side effects and long-term complications, scanning beam proton therapy is employed, when available. While this recent technological advance significantly reduces damage to surrounding healthy brain tissue, survivors continue to experience induced radiation damage, including neurocognitive sequelae. To impact survivors’ health-related quality of life and caregivers’ emotional and financial burden, it is critical to identify approaches that reduce RT dose to mitigate side-effects without impacting RT effectiveness. We are investigating targeting a unique MB electrochemical vulnerability as a means to sensitize MB tumor cells to RT. There are four MB molecular subgroups: wingless, sonic-hedgehog, Group 3, and Group 4. Our analysis of 763 MB tumor transcriptomes reveals that all Group 3 MB tumors share an enhanced expression of genes-coding for subunits of the Type-A GABA receptor (GABAAR), a chloride channel. Using patch-clamp electrophysiology, we found that GABAARs conduct Cl− in MB cells and that a brain-penetrant benzodiazepine (BZ) enhances this effect and triggers cytotoxic responses commensurate with mitochondrial depolarization. We find that BZ combined with RT, even at a sub-lethal dose, is highly effective in impairing the viability of MB tumor cells, greater than RT alone. Our BZis capable of penetrating the blood-brain barrier in minutes, is metabolically stable, and showed no toxicity in a primate model. We are investigating its suitability to be used concomitant with proton beam radiotherapy, replacing standard of care vincristine, to reduce radiation-induced brain toxicity experienced by MB patients and survivors while not decreasing RT effectiveness.
Citation Format: Daniel Pomeranz Krummel, Laura Kallay, Debanjan Bhattacharya, Vaibhavkumar Gawali, Kamdem T. Donatien, Taukir Ahmed, James M. Cook, Michael Lamba, Susanne Wells, Ralph E. Vatner, Mathieu Sertorio, Dan T. Ionascu, Soma Sengupta. Targeting a unique electrochemical vulnerability in a pediatric brain tumor to potentiate proton beam radiotherapy [abstract]. In: Proceedings of the AACR Virtual Special Conference on Radiation Science and Medicine; 2021 Mar 2-3. Philadelphia (PA): AACR; Clin Cancer Res 2021;27(8_Suppl):Abstract nr PO-009.
Abstract PO-012: Ultra-high dose rate (FLASH) irradiation does not alter microhomology mediated recombination under varying oxygen tension when compared to standard clinical dose rates
Authors: Barghouth Paul , Ollivier Jonathan , Montay-Gruel Pierre , Loo Billy W. , Vozenin Marie-Catherine , Limoli Charles , Frock Richard 
Published: April 2021

Abstract
The mechanism(s) driving the enhanced therapeutic ratio of ultra-high dose-rate radiotherapy (FLASH-RT) over slower conventional (CONV) ionizing radiation (IR) dose-rate are not known. However, attenuated DNA damage and transient oxygen depletion are among a number of proposed models. In this study, we employ high-throughput genome-wide translocation sequencing (LAM-HTGTS), a highly-sensitive assay used to identify “prey” DNA double strand breaks (DSBs) via their translocation to a single CRISPR-Cas9 “bait” DSB break, to investigate the potential differences in DSBs and repair generated by 10 Gy delivered at CONV (0.13 Gy/s) or FLASH (5.106 Gy/s) dose rates with the eRT6 (PMB-Alcen, CHUV). Investigations were conducted under different oxygen tensions. IR exposure in HEK293T cells at normoxic (21% O2) conditions increased both the proportion and total number of translocations from the junctions recovered, as expected, but were indistinguishable between CONV-RT and FLASH-RT dose-rates. Although, increased proportions of translocations were observed as cells were acutely transitioned to either physioxic (4%) or hypoxic (&lt;2%) conditions alone, the combined decrease in oxygen tension with IR dose-rate modulation did not reveal overt differences in the level of increased translocations nor in junction structures, which were predominantly increased in microhomology utilization. We discuss these findings with other related LAM-HTGTS studies.
Citation Format: Paul Barghouth, Jonathan Ollivier, Pierre Montay-Gruel, Billy W. Loo Jr., Marie-Catherine Vozenin, Charles Limoli, Richard Frock. Ultra-high dose rate (FLASH) irradiation does not alter microhomology mediated recombination under varying oxygen tension when compared to standard clinical dose rates [abstract]. In: Proceedings of the AACR Virtual Special Conference on Radiation Science and Medicine; 2021 Mar 2-3. Philadelphia (PA): AACR; Clin Cancer Res 2021;27(8_Suppl):Abstract nr PO-012.
Abstract PO-021: Single-cell DNA sequencing as a means to directly examine the size and frequency of radiation-induced mutations - An exploratory study
Authors: Mathew Felix , Yeo Jonathan , Galarneau Luc , Ybarra Norma , Tonin Patricia , Wang Yu Chang , Ragoussis Ioannis , Kildea John 
Published: April 2021

Abstract
This study examines if single-cell DNA sequencing may be used to study the mutational effects of ionizing radiation. As the action of ionizing radiation is a stochastic process, each cell in an irradiated sample experiences its own unique radiation-induced DNA damage. As a result, conventional sequencing methods such as bulk cell sequencing cannot be used to identify individual mutations. In this work, Epstein-Barr virus (EBV) transformed B-lymphoblastoid cells were irradiated with 6 MV X-ray radiation using a medical linear accelerator. Four samples of cells from the same population (400,000 cells/ml) were exposed to sham irradiation (0 Gray [Gy]; control), 0.5 Gy, 1.5 Gy and 3.0 Gy respectively at a common dose rate of about 600 cGy/min. Irradiated samples were incubated for 24 hrs and subsequently underwent single-cell whole-genome DNA sequencing to characterize the radiation impact. Mutational profiles of approximately 500 cells, randomly selected from each sample, were individually analyzed and compared to identify the variation of several mutational parameters as a function of dose. We quantified the copy number variations (CNV) for each cell in our samples. Additionally, we segregated insertion CNVs and deletion CNVs and independently analyzed their dose dependences. We found that the total number of CNVs (insertion and deletion combined) increased with dose, and the number of deletion CNVs consistently increased most. We have repeated the experiment and a new round of single-cell DNA sequencing is underway. If confirmed, our results will demonstrate that the mutational effects of ionizing radiation may be examined directly using single-cell sequencing.
Citation Format: Felix Mathew, Jonathan Yeo, Luc Galarneau, Norma Ybarra, Patricia Tonin, Yu Chang Wang, Ioannis Ragoussis, John Kildea. Single-cell DNA sequencing as a means to directly examine the size and frequency of radiation-induced mutations - An exploratory study [abstract]. In: Proceedings of the AACR Virtual Special Conference on Radiation Science and Medicine; 2021 Mar 2-3. Philadelphia (PA): AACR; Clin Cancer Res 2021;27(8_Suppl):Abstract nr PO-021.
Abstract PO-030: The harmala alkaloid harmine as a novel cancer cell radiosensitizer
Authors: Smack Caleb R.P. , Lafargue Audrey , Lam Christine , Carrieri Francesca A. , Siddiqui Ismaeel , Wang Hailun , Tran Phuoc T. 
Published: April 2021

Abstract
Radiation therapy resistance remains a persistent clinical challenge in the treatment of multiple different cancer types. Better appreciation of novel molecular targets to improve radiation therapy efficacy is needed. TWIST1 is an epithelial-mesenchymal transcription factor whose expression is linked to therapy resistance, including radioresistance, in cancer. We have shown previously that the harmala alkaloid harmine degrades TWIST1 and possess anti-tumor activity. We hypothesized that harmine may radiosensitize cancer cells via downregulation of TWIST1. We examined the effects of harmine combined with radiation (RT) on two TWIST1 overexpressing tumor cell lines, A549 human non-small cell lung cancer (NSCLC) cells and the LMT mouse-derived hepatocellular cancer cell line (HCC), both with doxycycline-inducible Twist1 expression. We also used the LM mouse-derived HCC cell line without Twist1 expression as a control. In vitro assays for clonogenic survival, apoptosis, cell cycle distribution, γH2AX foci kinetics, and protein expression in pathways important for cancer cell survival and radioresistance were performed. Harmine alone exhibited anti-cancer activity irrespective of Twist1 expression as shown by decreased clonogenic survival. Harmine caused a supra-additive radiosensitization in all cancer cell lines with radiation enhancement ratios between 1.05 – 3.04. In vivo we are evaluating tumor growth delay and effects of combined harmine and RT treatment in a NSCLC hind-flank tumor growth model. Mechanistic elucidation of these results, studies on normal cells, and in vivo validation are ongoing.
Citation Format: Caleb R.P. Smack, Audrey Lafargue, Christine Lam, Francesca A. Carrieri, Ismaeel Siddiqui, Hailun Wang, Phuoc T. Tran. The harmala alkaloid harmine as a novel cancer cell radiosensitizer [abstract]. In: Proceedings of the AACR Virtual Special Conference on Radiation Science and Medicine; 2021 Mar 2-3. Philadelphia (PA): AACR; Clin Cancer Res 2021;27(8_Suppl):Abstract nr PO-030.
Abstract PO-033: Papaverine derivative smv-32 alleviates tumor hypoxia and radiosensitizes tumors by inhibiting mitochondrial metabolism
Authors: Benej Martin , Wu Jinghai , Kreamer McKenzie , Vibhute Sandip , Papandreou Ioanna , Denko Nicholas C. 
Published: April 2021

Abstract
Radiation therapy is a standard type of treatment modality used to achieve local control in more than 50% of all cancer patients. However, tumor hypoxia reduces the effectiveness of radiation therapy by limiting the biologically effective dose. We identified that FDA-approved phosphodiesterase 10A (PDE10A) inhibitor papaverine (PPV) has an off-target effect inhibiting mitochondrial oxygen consumption (OCR) leading to acute reduction of tumor hypoxia and significant radiosensitization of model tumors. Our data suggests that PDE10A does not contribute to the radiosensitizing effect. Based on PPV’s structure, we used biomedicinal chemistry approach to engineer its novel derivative SMV-32 with reduced PDE10A inhibition. We used Seahorse metabolic flux analyzer to determine the effect of PPV and SMV-32 on mitochondrial OCR in vitro. Near-infrared optical spectroscopy and pODD-luciferase in vivo reporter system was used for pharmacodynamics analyses and dose response evaluation. Local radiation therapy was delivered using Small Animal Radiation Research Platform (SARRP). We compared intraperitoneal (IP) and intravenous (IV) delivery and optimized dosing using pODD luciferase reporter system. SMV-32 showed superior OCR inhibition in vitro and enhanced hypoxia reduction in vivo compared to PPV. A single clinically relevant dose of PPV or SMV-32 significantly reduced the hypoxic fractions of heterotopic and orthotopic tumors in mice and sensitized the tumors to radiation therapy. PPV and SMV-32 appear to be ideal candidates for clinical radiosensitization. PPV is already in phase I clinical trial for treatment of non-small cell lung cancer combined with stereotactic body radiation therapy.
Citation Format: Martin Benej, Jinghai Wu, McKenzie Kreamer, Sandip Vibhute, Ioanna Papandreou, Nicholas C. Denko. Papaverine derivative smv-32 alleviates tumor hypoxia and radiosensitizes tumors by inhibiting mitochondrial metabolism [abstract]. In: Proceedings of the AACR Virtual Special Conference on Radiation Science and Medicine; 2021 Mar 2-3. Philadelphia (PA): AACR; Clin Cancer Res 2021;27(8_Suppl):Abstract nr PO-033.
Abstract PO-066: Relationship between KEAP1/NFE2L2 pathway activation and radiation resistance in oral cavity cancer
Authors: Guan Li , Cao Hongbin , Hui Angela , Kwok Shirley , Viswanathan Vignesh , Nambiar Dhanya , Eyben Rie V. , Holmes Brittany , Kong Christina , Diehn Maximilian , Le Quynh-Thu 
Published: April 2021

Abstract
Radiotherapy (RT) is one of the primary treatment modalities for head and neck squamous cell carcinoma (HNSCC) either in the definitive or the adjuvant setting. Unfortunately, despite therapeutic and technological advances in radiotherapy, some patients will have persistence tumor or develop locoregional failure, resulting in significant morbidity and mortality. Presently, there is no biomarker that can reliably identify HNSCC that is resistant to RT. Recent genomic sequencing studies show that mutations in the KEAP1/NFE2L2 pathway exist in HNSCC. However, very little data is available with regards to the relationship between RT resistance and activating mutation or pathway hyperactivation of this pathway in HNSCC. Moreover, the mechanism by which dysregulation of this pathway can lead to RT resistance in HNSCC is poorly understood. Therefore, the project is aimed to study the relationship between KEAP1/NFE2L2 mutations and patient outcomes in HNSCC. To address this aim, DNA sequencing strategies and tissue microarray (TMA) are used to identify mutations and/or a hyperactivation protein signature of the KEAP1/NFE2L2 oxidative stress pathway in an oral cavity cancer patient cohorts (N = 69[MOU1]) treated with surgery and adjuvant RT. In addition, identified mutations are introduced into HNSCC cell lines and mouse xenografts to study the effect of these mutations on radiation response and to identify the mechanism by which they mediate radiation resistance. Here we find that 6% of oral cavity cancer patients harbor mutation in this pathway, primarily in a hotspot in the NFE2L2 gene. NFE2L2 mutation is associated with 100% in-field recurrence after radiotherapy. Strong co-expression of two downstream targets of this pathway (HO1 and NQO1) in tumor cells on the TMA strongly correlates with NFE2L2 mutation and in-field recurrence after RT. Finally, overexpression of the mutated NFE2L2 gene in HNC cell lines lead to increased ROS and radioresistance. Our findings suggest oral cavity cancers harboring activating mutation or a hyperactivation protein signature of the KEAP1/NFE2L2 pathway are more radioresistant. Work is ongoing to validate these findings in other types of HNSCC and to determine how to enhance radiation effectiveness in mutated tumors.
Citation Format: Li Guan, Hongbin Cao, Angela Hui, Shirley Kwok, Vignesh Viswanathan, Dhanya Nambiar, Rie V. Eyben, Brittany Holmes, Christina Kong, Maximilian Diehn, Quynh-Thu Le. Relationship between KEAP1/NFE2L2 pathway activation and radiation resistance in oral cavity cancer [abstract]. In: Proceedings of the AACR Virtual Special Conference on Radiation Science and Medicine; 2021 Mar 2-3. Philadelphia (PA): AACR; Clin Cancer Res 2021;27(8_Suppl):Abstract nr PO-066.
Abstract PO-070: Boost tumor response to radiation therapy: What can we learn from PTEN-deficient models?
Authors: Fan Xinyi , Qiu Miaoyan , Formenti Silvia C. , Shen Wen H. 
Published: April 2021

Abstract
PTEN is among the most frequently mutated genes in nearly all types of cancer. TCGA studies reported mutation or deletion of the PTEN gene in 11% of breast invasive carcinoma and 9% of colorectal adenocarcinoma. Cancer-associated PTEN deficiency is associated with worse prognosis as well as tumor resistance to therapies, including chemotherapy and immunotherapy. However, it is largely controversial, as there is no consensus regarding how PTEN deficiency alters tumor response to radiation therapy (RT). RT elicits anti-cancer efficacy through both cell-autonomous and non-cell-autonomous mechanisms by disrupting the cancer genome and by promoting immune responses. Similarly, loss of PTEN results in genomic instability and immune deregulation, which may lead to a tumor-specific net outcome of growth and response to RT. In order to characterize a pan-cancer phenotype of RT sensitivity, we created multiple isogenic pairs of tumor cells of different tissue origins. Our studies, using both a breast cancer model and a colon cancer model, demonstrate that PTEN deficiency confers an enhanced RT efficacy through a non-cell autonomous mechanism. Specifically, orthotopically implanted tumors lacking PTEN regressed significantly following single-dose RT that was less effective in suppressing PTEN-proficient tumors. A more efficient regimen (3*8Gy) became ablative and achieved 100% tumor-free survival only in the hosts of PTEN-deficient tumors. The RT sensitivity manifested in PTEN-mutant tumors in vivo is likely due to enhanced immunogenicity, because in vitro, PTEN-deficient cancer cells not only lost such vulnerability but often exhibited RT resistance. Our data suggest that PTEN-deficient tumor phenotypes may be exploited to achieve the highest cancer elimination rate, using a combinatorial strategy to promote non-cell-autonomous immunogenicity and to concurrently overcome cell-autonomous RT resistance.
Citation Format: Xinyi Fan, Miaoyan Qiu, Silvia C. Formenti, Wen H. Shen. Boost tumor response to radiation therapy: What can we learn from PTEN-deficient models? [abstract]. In: Proceedings of the AACR Virtual Special Conference on Radiation Science and Medicine; 2021 Mar 2-3. Philadelphia (PA): AACR; Clin Cancer Res 2021;27(8_Suppl):Abstract nr PO-070.
Abstract PO-071: Characterizing transcriptomic indicators of radiosensitivity in cancer and identifying sensitizing therapeutic agents
Authors: Smith Ian , Bell Rachel , Lambie Meghan , Haibe-Kains Benjamin , Bratman Scott 
Published: April 2021

Abstract
While radiation therapy is an integral method for cancer treatment, clinical choices are not currently informed by the genetic and molecular profile of a patient’s tumor. Though it has been shown that genetic features implicate variability, the exact relationship between these features and radiosensitivity is poorly understood. Our work focuses on predicting radiosensitivity of squamous cell carcinoma from molecular features. First, we employ RadioGx, a computational platform for integrative analysis of radiogenomic datasets, to identify a gene expression signature predictive of radiosensitivity. To mitigate the high-dimensionality of gene expression data, we employ pathway-level transcriptomic modeling methods to identify cellular programs associated with radiation sensitivity. Our pancancer radiosensitivity model achieves a Pearson’s correlation of 0.47 with measured radiosensitivity from a radiogenomic dataset using only high level transcriptomic features. Second, we use that gene expression signature to query the Connectivity Map via the PharmacoGx resource and identify candidate radiosensitizers - compounds that may induce the radiosensitivity signature. Further validation is necessary to evaluate the efficacy of these compounds at improving radiosensitivity in both model systems and patient contexts. These results implicate cellular processes in radiosensitivity and advance an approach for identifying radiosensitizing agents through integration of large scale datasets.
Citation Format: Ian Smith, Rachel Bell, Meghan Lambie, Benjamin Haibe-Kains, Scott Bratman. Characterizing transcriptomic indicators of radiosensitivity in cancer and identifying sensitizing therapeutic agents [abstract]. In: Proceedings of the AACR Virtual Special Conference on Radiation Science and Medicine; 2021 Mar 2-3. Philadelphia (PA): AACR; Clin Cancer Res 2021;27(8_Suppl):Abstract nr PO-071.
Abstract PO-099: Overexpression of proinflammatory chemokines CCL5 and CCL17 after gene electrotransfer to murine tumors modifies their cytokine expression profile and leads to tumor cures in combination with tumor irradiation
Authors: Sersa Gregor , Bozic Tim , Markelc Boštjan , Cemazar Maja , Brezar Simona Kranjc 
Published: April 2021

Abstract
Proinflammatory chemokines are small signaling proteins, with the ability to induce migration of different types of immune cells. The degree and type of immune cell infiltrate in the tumor microenvironment often correlates with the outcome of immunotherapies in cancer patients. Therefore, combining chemokines with classical, but immune response activating therapy, such as irradiation presents one of the potential approaches in cancer immunotherapy. Through the use of plasmid DNA encoding either proinflammatory chemokine CCL5 or CCL17 we studied their effects on cytokine expression profile in vitro and in vivo in murine breast (4T1, E0771) and colon (CT26, MC38) cancer models. While in vitro plasmid DNA was introduced in the cells using lipofection, gene electrotransfer was utilized in case of tumors in vivo. Viability of all cell lines 48 h after lipofection remained above 80%. Using qRT-PCR expression of 11 cytokines was determined 48 h after lipofection, which showed significantly increased expression of CCL5, CCL17 demonstrating successful transfection. Moreover, increased levels of IL-6 and CXCL10 were also observed in the surviving cells. Gene electrotransfer after intratumoral injection of plasmid DNA encoding either CCL5 or CCL17 in CT26 and 4T1 murine tumor model (animal license: U34401-1/2015/43) resulted in minor tumor growth delay. Concurrent expression analysis of 7 cytokines after gene electrotransfer in tumors showed overexpression of both chemokines, while levels of proinflammatory cytokines IL-6, IL-12 and IFNγ were modestly increased. Obtained altered expression profile, both in vitro and in vivo, is typical for inflammation. Furthermore, irradiation of CT26 and 4T1 tumors combined with gene electrotransfer of plasmids encoding CCL5 or CCL17 resulted in significant tumor growth delay and even tumor cures. Therefore, based on changes in tumor microenvironment after therapy future experiments will be focused towards elucidating the mechanisms of immune response and determining the optimal time window for combined tumor irradiation and gene electrotransfer of plasmids encoding chemokines CCL5 and CCL17.
Citation Format: Gregor Sersa, Tim Bozic, Boštjan Markelc, Maja Cemazar, Simona Kranjc Brezar. Overexpression of proinflammatory chemokines CCL5 and CCL17 after gene electrotransfer to murine tumors modifies their cytokine expression profile and leads to tumor cures in combination with tumor irradiation [abstract]. In: Proceedings of the AACR Virtual Special Conference on Radiation Science and Medicine; 2021 Mar 2-3. Philadelphia (PA): AACR; Clin Cancer Res 2021;27(8_Suppl):Abstract nr PO-099.