bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract LB-016: Nutlin and oxaliplatin induce p53-dependent addiction to FLIP
Authors: McIntyre Alexander , Falcone Fiammetta , Johnston Patrick G. , Longley Daniel B. , McDade Simon S. 
Published: July 2016

Abstract
Background: The tumour suppressive functions of the p53 transcription factor are inactivated through mutations or suppressed through non-mutational mechanisms in almost all cancer cells. This work focusses on identifying mechanisms through which, tumours retaining wild-type p53 evade apoptosis in response to chemotherapies and p53 agonists such as Nutlin-3A.
Methods: A panel of matched p53 wild-type and deficient colorectal cancer cell line models were studied, using Nutlin-3A and oxaliplatin as direct and indirect p53 activating agents. A number of molecular (Western blots, RT-PCR), phenotypic (cell death) and genomic analyses were used to investigate the importance of p53 and its downstream transcriptional programs.
Results: We demonstrate the importance of p53 in priming cancer cell sensitivity to apoptotic cell death following treatment with Nutlin-3A or oxaliplatin through activation of pro-apoptotic p53 targets, such as TRAIL-R2, Fas/CD95, PUMA and NOXA. Surprisingly, our analysis further reveals that this priming is accompanied by a parallel early p53-dependent pro-survival response that imposes a critical dependence on the caspase-8 inhibitor FLIP. Preventing FLIP up-regulation with siRNA resulted in synergistic increases in apoptosis in response to Nutlin-3A and oxaliplatin in p53 wild-type, but not p53 null cells. p53-mediated FLIP up-regulation was blocked by pharmacological inhibition of HDACs1-3 using Entinostat, which caused hyper-acetylation of the p53 C-terminus and altered transactivation of a number of other p53 apoptotic target genes. Notably, the synergy between Nutlin-3A or oxaliplatin and Entinostat was abrogated in cells over-expressing FLIP trans-genes or in cells in which caspase-8 was depleted using RNAi.
Conclusion: These results uncover a p53-regulated apoptosis priming event, in which a number of key pro-apoptotic genes are upregulated in response to direct p53 agonism (Nutlin-3A) or indirect activation downstream of DNA damage (oxaliplatin). However, immediate commitment to apoptosis is prevented by the concomitant p53-mediated up-regulation of FLIP. This may be a mechanism that has evolved to allow DNA damage repair time to take place, while priming the cell to undergo apoptosis if the damage is irreparable. From a cancer therapeutics point-of-view, this work identifies FLIP upregulation in p53 wild-type cancers as a key target for overcoming resistance to direct and indirect p53 activating therapies.
Citation Format: Alexander McIntyre, Fiammetta Falcone, Patrick G. Johnston, Daniel B. Longley, Simon S. McDade. Nutlin and oxaliplatin induce p53-dependent addiction to FLIP. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr LB-016.
Abstract LB-046: Mechanism and consequences of HDAC6 regulation by RanBPM
Authors: Salemi Louisa , Wang Xu , Hess David , Schild-Poulter Caroline 
Published: July 2016

Abstract
Ran-binding protein M (RanBPM) has been shown to interact with numerous proteins, implicating it in a variety of cellular processes including cell adhesion, migration, microtubule dynamics, and gene transcription. Work in our laboratory previously identified RanBPM as an activator of apoptosis induced by DNA damage. Our studies have also suggested a tumour suppressor role for RanBPM, as its downregulation not only disrupted apoptotic activation, but lead to loss of growth factor dependence and increased rates of cell migration. Here we show that RanBPM downregulation promotes tumour formation in orthotopic and metastasis mouse models, further suggesting a tumour-suppressive function for RanBPM. Recently, we characterized an interaction between RanBPM and Histone Deacetylase 6 (HDAC6). HDAC6 is a cytoplasmic deacetylase with an important role in cell migration. Its substrates include α-tubulin, cortactin and Hsp90. Increased HDAC6 expression and/or activity has been demonstrated to promote cell migration and tissue invasiveness. HDAC6 has also been shown to be required for oncogenic transformation and tumour formation. Upregulated HDAC6 has been observed in a number of different cancers and recently, specific HDAC6 inhibitors have been found to inhibit cell growth and prevent tumour formation in mouse models. We previously identified that the interaction between RanBPM and HDAC6 mediates the inhibition of HDAC6. Here we demonstrate that the LisH domain of RanBPM specifically, is responsible for the association with HDAC6. RanBPM also interacts with α-tubulin at microtubules and this localization is dependent on HDAC6, whereas HDAC6 localization at microtubules is independent of RanBPM. RanBPM has been identified to be part of a large protein complex, termed the CTLH complex. Components of the complex are conserved from the homologous yeast complex, the Gid complex, which functions as an E3 ubiquitin ligase complex. Here we evaluate HDAC6 regulation by the CTLH complex and asses co-localization of the CTLH complex with microtubules, specifically α-tubulin. Overall, our results suggest that the tumour suppressor functions of RanBPM could stem, at least in part from an inhibition of the oncogenic activities of HDAC6.
Citation Format: Louisa Salemi, Xu Wang, David Hess, Caroline Schild-Poulter. Mechanism and consequences of HDAC6 regulation by RanBPM. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr LB-046.
Abstract LB-051: Cancer cell binding, internalization and intracellular localization of a novel therapeutic peptide SOR-C13 targeting the TRPV6 oncochannel
Authors: Davey Michelle , Dugourd Dominique , Lutes Tyler , Rice Christopher , Gormley Sean , St. Pierre Stephanie , Stewart John M. 
Published: July 2016

Abstract
SOR-C13, a 13-mer peptide derived from soricidin, the paralytic protein component of saliva of the Northern Short-tailed shrew, has recently completed a phase I clinical trial for the treatment of epithelial-derived cancers. SOR-C13 specifically targets and inhibits the TRPV6 calcium channel - a recognized oncochannel over-expressed in a number of epithelial cancers (e.g. breast, ovarian, prostate). SOR-C13 is the first TRPV6-targeting drug to enter clinical development. Xenograft and fluorescent imaging studies provide in vivo evidence of SOR-C13 efficacy in a range of epithelial tumors as well as SOR-C13's preferential accumulation at tumour sites. To demonstrate the specificity of the peptide for TRPV6 and determine its fate, modified SOR-C13 peptide was labeled with fluorescein to enable monitoring of cellular binding and internalization in high versus low TRPV6 cancer cell lines. Various organelle-specific fluorescent trackers for nuclei, actins, lysosomes, and endoplasmic reticula were paired with labeled SOR-C13 peptides and anti-TRPV6 antibody in fluorescence imaging studies to monitor intracellular trafficking. Rapid peptide binding and internalization was observed on incubation of fluorescently labeled SOR-C13 with a breast cancer cell line (T-47D) expressing high levels of the ion channel. Significantly less SOR-C13 binding was observed in an ovarian cancer cell line (SKOV-3) with low TRPV6 levels. Fluorescently labeled SOR-C13 scramble peptide was included as a control and did not bind to high TRPV6 cells. Co-localization studies did not demonstrate a clear association of the fluorescently labeled SOR-C13 with lysosomes, the ER or actin. This study demonstrates that SOR-C13 not only specifically binds to TRPV6-expressing cancer cells according to their level of TRPV6 expression but is also internalized. The correlation of TRPV6 expression in tumors and clinical efficacy will be evaluated during the next SOR-C13 clinical trials. Additionally, these results set the stage for further development of SOR-C13-based peptide drug conjugates for TRPV6 targeted anti-cancer therapies.
Citation Format: Michelle Davey, Dominique Dugourd, Tyler Lutes, Christopher Rice, Sean Gormley, Stephanie St. Pierre, John M. Stewart. Cancer cell binding, internalization and intracellular localization of a novel therapeutic peptide SOR-C13 targeting the TRPV6 oncochannel. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr LB-051.
Abstract LB-054: Small molecule inhibitors of the hexosamine biosynthetic pathway and the cancer O-GlcNAcome
Authors: Saeui Christopher T. , Yarema Kevin 
Published: July 2016

Abstract
In recent years, the long-known Warburg effect–wherein cancer cells utilize abnormally high levels of glucose by forgoing oxidative phosphorylation–has been rediscovered but its impact on flux through the hexosamine biosynthetic pathway (HBP) remains relatively unexplored. In this work, we reasoned that UDP-GlcNAc, the end product of the HBP, could promote cancer by increasing the activity of O-GlcNAc transferase (OGT) and subsequently perturb global patterns of protein O-GlcNAcylation. To combat increased O-GlcNAcylation, which is increasingly being linked to cancer cell survival, metastasis, and tumor aggressiveness, most efforts to date have focused on direct inhibition of OGT. In contrast, we take an alternate approach by developing first-in-class small molecules that target UDP-N-acetylglucosamine pyrophosphorylase 1/2 (UAP1/2), the final enzyme of the HBP; this strategy has the added benefit of also potentially reducing the production of highly-branched N-glycans associated with cancer and other diseases. In our first biological tests, presented here, we show that our UAP1/2 inhibitors decrease intracellular UDP-GlcNAc levels as intended and modulate the cancer O-GlcNAcome in a way consistent with reduced viability of difficult-to-treat pancreatic and brain cancer cell lines observed in treated cells. Finally, our strategy of targeting UAP1/2 and the cancer O-GlcNAcome decreased the expression of oncoproteins such as c-Myc, YAP, and TAZ which are all linked to highly aggressive and difficult-to-treat types of cancer. In summary, we have developed first-in-class of small molecules that successfully target UAP1/2, inhibit flux through the HBP, reduce global patterns of O-GlcNAcylation, and knock-down several endpoints linked to cancer progression.
Citation Format: Christopher T. Saeui, Kevin Yarema. Small molecule inhibitors of the hexosamine biosynthetic pathway and the cancer O-GlcNAcome. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr LB-054.
Abstract LB-060: A novel target for genetic silencing of AXL mediates taxane resistance, invasion, and migration in uterine cancer
Authors: Palisoul Marguerite , Nguyen Mai , Pan Hua , Lohrey Anne , Wickline Samuel , Powell Matthew , Mutch David , Fuh Katherine 
Published: July 2016

Abstract
Objectives: We investigated the role of AXL expression in chemotherapy response in uterine papillary serous cancer, and sought to reverse chemoresistance through inactivation of AXL. Methods: In vitro cell viability (XTT) assays were performed to confirm response to chemotherapy in AN3CA (taxane sensitive) and ARK1 (taxane resistant) uterine cell lines. AXL knockdown by siRNA was performed with either a traditional transfection reagent (DharmaFECT) or with a novel serum-stable, cell-penetrating, endosomolytic amphipathic peptide delivery system (p5RHH). Following knockdown of AXL using siRNA and p5RHH, chemotherapy response was assessed by XTT assay and invasion and migration assays were performed. Cell viability assays were analyzed using multiple t-tests. P &lt; 0.05 was considered statistically significant. Results: Expression of AXL was found to be associated with a worse prognosis in uterine cancer. Chemoresistance was validated with XTT assays for AN3CA and ARK1. Western blotting confirmed over-expression of AXL in the chemoresistant cell line, and lack of AXL expression in its chemosensitive counterparts. Reversal of paclitaxel resistance was achieved in ARK1 cells genetically by silencing AXL with shRNA. The novel delivery system, p5RHH, combined to siAXL, was shown to inactivate AXL in ARK1 cells at the RNA and protein level to a similar extent as traditional transfection technique (8.4-fold vs 8.7-fold decrease for RNA, respectively; 67% vs 83% knockdown at 48h and 84% vs 97% knockdown at 96 hours for protein, respectively). Reversal of paclitaxel resistance was achieved in ARK1 cells therapeutically and genetically using the p5RHH-siAXL complex. With AXL silencing using the p5RHH-siAXL complex, tumor cell invasion was inhibited by greater than 40%, and tumor cell migration was inhibited by greater than 60%. Conclusions: AXL expression is associated with chemoresistance in a uterine papillary serous cancer cells. Genetic inactivation of AXL in a taxane-resistant uterine cancer cells reverses chemoresistance. A novel siRNA nano-particle delivery system was successfully utilized to mimic genetic inactivation resulting in improved chemotherapy response and decreased invasion and migration.
Citation Format: Marguerite Palisoul, Mai Nguyen, Hua Pan, Anne Lohrey, Samuel Wickline, Matthew Powell, David Mutch, Katherine Fuh. A novel target for genetic silencing of AXL mediates taxane resistance, invasion, and migration in uterine cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr LB-060.
Abstract LB-071: Allele-specific inhibitors inactivate mutant KRAS G12C by a trapping mechanism
Authors: Lito Piro , Solomon Martha , Hansen Rasmus , Li Lian-Sheng , Rosen Neal 
Published: July 2016

Abstract
Oncogenic mutations impair the GTPase activity of RAS, causing it to accumulate in the activated, GTP-bound conformation. Here we describe the mechanism of action of a novel compound that binds to KRASG12C to selectively inhibit proliferation and induce apoptosis in cancer cells with this mutation. The inhibitor interacted preferentially with the GDP-bound form of the protein, yet it reduced the level of GTP-bound KRASG12C. This suggested that GTPase activity is required for inhibition, which turned out to be the case. The inhibitor traps GDP-bound KRASG12C and prevents nucleotide exchange to the GTP-bound form. Genetic experiments revealed that mutants completely lacking GTPase activity, and those promoting exchange, reduced the potency of the drug. In contrast, mutants with diminished exchange were more susceptible to inhibition. In agreement with these findings, targeting receptor signaling potentiated KRASG12C inhibition, whereas its activation had the opposite effect. This mechanism reveals that KRASG12C undergoes nucleotide cycle in cancer cells and provides a basis for the development of effective combination therapies to treat KRASG12C-driven cancers.
Citation Format: Piro Lito, Martha Solomon, Rasmus Hansen, Lian-Sheng Li, Neal Rosen. Allele-specific inhibitors inactivate mutant KRAS G12C by a trapping mechanism. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr LB-071.
Abstract LB-077: T cells conditioned with MDSC show an increased anti-tumor activity after adoptive T cell based immunotherapy
Authors: Raber Patrick , Sierra Rosa A. , Zhang Shuzhong , Thevenot Paul , Rodriguez Paulo C. 
Published: July 2016

Abstract
The success of adoptive T cell-based immunotherapy (ACT) in cancer is limited in part by the accumulation of myeloid-derived suppressor cells (MDSC), which block several T cell functions, including T cell proliferation and the expression of various cytotoxic mediators. Paradoxically, the inhibition of CD8+ T cell differentiation into cytotoxic populations increased their efficacy after ACT into tumor-bearing hosts. Therefore, we aimed to test the impact of conditioning CD8+ T cells with MDSC on their differentiation potential and ACT efficacy. Our results indicate that MDSC impaired the progression of CD8+ T cells into effector populations, without altering their activation status, production of IL-2, or signaling through the T cell receptor. In addition, culture of CD8+ T cells with MDSC resulted in an increased ACT anti-tumor efficacy, which correlated with a higher frequency of the transferred T cells and elevated IFNγ production. Interestingly, activated CD62L+ CD8+ T cells were responsible for the enhanced anti-tumor activity showed by MDSC-exposed T cells. Additional results showed a decreased protein synthesis rate and lower activity of the mammalian/mechanistic target of rapamycin (mTOR) in T cells conditioned with MDSC. Silencing of the negative mTOR regulator tuberous sclerosis complex-2 in T cells co-cultured with MDSC restored mTOR activity, but resulted in T cell apoptosis. These results indicate that conditioning of T cells with MDSC induces stress survival pathways mediated by a blunted mTOR signaling, which regulated T cell differentiation and ACT efficacy. Continuation of this research will enable the development of strategies to increase ACT responses in cancer.
Citation Format: Patrick Raber, Rosa A. Sierra, Shuzhong Zhang, Paul Thevenot, Paulo C. Rodriguez. T cells conditioned with MDSC show an increased anti-tumor activity after adoptive T cell based immunotherapy. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr LB-077.
Abstract LB-090: Sequence-based discovery of fully human anti-CD3 and anti-PDL1 single domain antibodies using novel transgenic rats
Authors: Trinklein Nathan , Force Aldred Shelley , Schellenberger Ute , Harris Kat , Clarke Starlynn , Dang Kevin , Pham Duy , Bruggemann Marianne , vanSchooten. Wim 
Published: July 2016

Abstract
We have created a new platform and method for discovering fully human single domain antibodies (UniDabs) by combining novel transgenic rats (UniRats), antibody repertoire sequencing, and high-throughput gene assembly, expression and screening. UniRats express a comprehensive human VH gene repertoire in a heavy chain only antibody format, and they mount robust immune responses to a variety of antigens. UniRats do not produce endogenous Ig as their heavy, kappa and lambda loci have been silenced, so the only Ig expression comes from the human heavy chain transgenes. Human VHs identified using high-throughput functional screening of heavy chain antibodies may also be converted to a single domain UniDab format. UniDabs are powerful and flexible modular binding domains that may be combined to form multivalent structures, nanoparticle conjugates, or antibody-drug conjugates. In our preclinical CD3 and PDL1 programs, we have identified hundreds of antigen-specific UniDabs. This large collection of UniDabs covers a diverse set of epitopes, a wide range of affinities, and is a valuable resource for creating next-generation multi-specific cancer therapeutics.
Citation Format: Nathan Trinklein, Shelley Force Aldred, Ute Schellenberger, Kat Harris, Starlynn Clarke, Kevin Dang, Duy Pham, Marianne Bruggemann, Wim vanSchooten. Sequence-based discovery of fully human anti-CD3 and anti-PDL1 single domain antibodies using novel transgenic rats. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr LB-090.
Abstract LB-091: Inhibition of Siglec-15 prevents bone loss in a mouse model of multiple myeloma
Authors: Tremblay Gilles B. , Moraitis Anna , Vanderkerken Karin , Filion Mario 
Published: July 2016

Abstract
Multiple myeloma (MM) is a B-cell malignancy associated with infiltration and growth of plasma cells in the bone marrow resulting in end-organ damage including devastating osteolytic bone disease. We examined the ability of 25B2, an antibody targeting Siglec-15, to prevent bone loss in the 5T2MM syngeneic model of MM. C57BlKaLwRij male mice (n = 10/group) were injected with 5T2MM cells and 24h later treated for 12 weeks with the PBS, 25B2 (10 mg/kg, q3d), bortezomib (0.7 mg/kg, q3d) or a combination of 25B2 and bortezomib. 25B2 treatment caused a 3.7-, 5.4- and 1.2-fold increase in bone volume (%BV/TV) compared to PBS-treated mice in the tibia, femur and lumbar vertebra (LV), respectively. Increases in bone volume were also seen with bortezomib with 3.1-, 4.1- and 1.4-fold increases in the tibia, femur and LV, respectively. Combination of the two agents further increased%BV/TV by 6.9-, 10.5- and 1.5-fold in the tibia, femur and LV, respectively, when compared to the PBS treated mice. All of the changes were statistically significant with the exception of those in the LV. Unlike bortezomib treatment, which inhibits the growth of 5T2MM cells in this model, there was no direct effect of 25B2 on tumor burden in 5T2MM mice when the percentage of plasmacytosis and the serum paraprotein levels were measured. However, 25B2 caused a significant decrease in the number of bone lesions by 49.5%. The number of lesions in the bortezomib group decreased by 71.7%, but there was no significant difference between the 25B2 and bortezomib groups. The number of lesions decreased by 89.4% in the combination group. Consistent with the mechanism of action of Siglec-15 antibodies, osteoclasts were rendered inactive, however cross-talk with bone-forming osteoblasts was likely maintained. This unique mechanism of action would be particularly appropriate for MM, where osteolytic disease is not only the result of increased osteoclast activity but also decreased osteoblast-mediated bone formation. The 5T2MM model is one of the most representative of the human pathology and therefore, the effect observed in response to the Siglec-15 antibody holds the promise that such a treatment in MM patients could provide benefit and further delay skeletal related events.
Citation Format: Gilles B. Tremblay, Anna Moraitis, Karin Vanderkerken, Mario Filion. Inhibition of Siglec-15 prevents bone loss in a mouse model of multiple myeloma. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr LB-091.