bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract 4637: Chk1 inhibition: a promising targeted treatment for head and neck squamous cell carcinoma
Authors: van Harten Anne M. , Stigter-van Walsum Marijke , Buijze Marijke , Braakhuis Boudewijn Jm , Brakenhoff Ruud H. 
Published: July 2016

Abstract
Over 90% of all malignant tumors in the head and neck region are squamous cell carcinomas (HNSCC), ranking within the top 10 of most common cancers worldwide. HNSCC arise in the mucosal linings of the upper aerodigestive tract, and known risk factors are tobacco use, excessive alcohol consumption and infection with high risk types of the human papillomavirus (HPV). Despite the application of intensive treatment protocols, the 5-years survival rate of HNSCC patients has hardly increased last decades and remained at approximately 50%. Therefore, new therapeutic possibilities are urgently awaited.
Previously, we identified CHEK1 as a candidate therapeutic target for HNSCC in a whole genome siRNA screen (Martens-de Kemp et al, Clin Cancer Res 2013). Additionally, a functional screen using a microRNA expressing library indicated that knockdown of ATM expression may cause a lethal effect in HNSCC cell lines as well (Lindenbergh-van der Plas et al, Clin Cancer Res 2013). The aim of the present study was to investigate whether interference with the ATM/ATR/CHEK1/CHEK2 DNA damage response pathway is indeed a promising therapeutic approach in HNSCC.
RNA interference using siRNAs targeting ATM, ATR, CHEK1 and CHEK2 confirmed that particularly CHEK1 is essential for the survival of a subset of HNSCC cell lines, whereas the cell viability of primary oral keratinocytes and fibroblasts was not compromised. This was confirmed in vitro by treatment with a small molecule inhibitor targeting Chk1, and a therapeutic window between cancer and normal oral mucosal cells was observed. Functional assays indicated an S-phase delay in Chk1 inhibited HNSCC cells, followed by DNA damage. The latter was indicated by elevated phosphorylation of ATM Ser1981 and γH2Ax Ser139, as well as the appearance of chromosomal breaks. The DNA damage response initiated caspase-mediated apoptosis, resulting in programmed cell death.
In summary, our data show that HNSCC cells appear to depend strongly on a functional Chk1 protein during DNA replication. Therefore, Chk1 inhibition seems an interesting therapeutic strategy for HNSCC, at least in a subset of tumors.
Citation Format: Anne M. van Harten, Marijke Stigter-van Walsum, Marijke Buijze, Boudewijn Jm Braakhuis, Ruud H. Brakenhoff. Chk1 inhibition: a promising targeted treatment for head and neck squamous cell carcinoma. [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 4637.
Abstract 4641: Bone marrow stromal cells frustrate temozolomide treatment of glioblastoma
Authors: Katakowski Mark , Pikula Elizabeth , Kalkanis Steven , Chopp Michael 
Published: July 2016

Abstract
Temozolomide (TMZ) is the most widely used for the treatment of glioblastoma. However, despite the effectiveness of TMZ, progression and recurrence are observed in nearly all patients. Here, we report a heretofore unknown mechanism of TMZ chemo-resistance mediated by circulating exosomes. Exosomes are small microvesicles released by cells that efficiently transfer their molecular cargo to other cells, including tumor. We recently found that in response to TMZ treatment, human bone marrow stromal cells (MSCs) release exosomes that confer TMZ chemo-resistance upon glioblastoma cells.
MSCs produce exosomes which can be found in circulating blood. TMZ is distributed systemically, thus we tested the effect of TMZ upon MSC-produced exosomes, and the profile of miRNAs within the exosomes. In addition, we tested if MSC exosomes altered the response of glioblastoma cells to TMZ. To test our hypotheses, we treated MSCs with TMZ, and performed miRNA PCR arrays upon exosomes produced by the MSCs (tMSC-exo). Furthermore, we exposed glioblastoma cells to tMSC-exo, and measured the effect upon tumor cell viability, and growth in the presence of TMZ. Finally, we collected serum exosomes from patients with glioblastoma upon resection, and after TMZ treatment. We tested if exosomes from these patients before and after TMZ treatment exhibit different chemo-resistive effects, and if TMZ treatment altered the miRNA profile in circulating exosomes.
We report that tMSC-exo elicit a protective effect upon glioblastoma cells treated with TMZ. The miRNA profile of MSC exosomes was also significantly altered by TMZ. Like MSC exosomes, TMZ treatment altered the miRNA profile of circulating exosomes in glioblastoma patients, and resulted in increased chemo-resistance conferred by the exosomes upon tumor cells.
Investigations of TMZ chemo-resistance have largely focused upon characteristics of the tumor cells the agent is intended to kill. Here, we elucidate a novel mechanism of resistance to TMZ which does not arise from the tumor itself. Our findings suggest that circulating exosomes may diminish the efficacy of TMZ treatment of glioblastoma.
Citation Format: Mark Katakowski, Elizabeth Pikula, Steven Kalkanis, Michael Chopp. Bone marrow stromal cells frustrate temozolomide treatment of glioblastoma. [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 4641.
Abstract 4653: Combination Azacitidine and histone deacetylase inhibition induces a multi factorial synergistic anti-tumor response in non-small cell lung cancer (NSCLC)
Authors: Topper Michael , Hanigan Christin , Vaz Michelle , Chiappinelli Katherine , Justin Julin , Murphy Lauren , Zahnow Cynthia , Baylin Stephen 
Published: July 2016

Abstract
Epigenetic therapy holds much promise as an emerging paradigm for the treatment of many disparate types of human cancer. However, the data in solid malignancies, particularly, would suggest further optimization is required to extract the true potential of these therapies. In our current study, we have deployed at low, clinically achievable doses, chronic combinatorial administration of the DNA methyltransferase inhibitor Azacitidine in conjunction with both benzamide and hydroxyamic acid based histone deacetylase inhibitors (HDACi) in NSCLC. We have developed our paradigms by sequentially employing chronic HDACi administration after Azacitidine. This strategy achieves durable alteration of the cell transcriptome with corresponding induction of both cell cycle arrest and apoptosis. These events appear driven by alterations, both transcriptionally and post transcriptionally of Myc and Myc regulatory proteins. Epigenetic treatment induced perturbation of Myc is facilitated by Wnt pathway inhibition through induction of Wnt antagonists, namely DKK proteins. Importantly, as part of this scenario of altering a Myc regulatory axis, there is a synergistic cytotoxic response mediated at least in part through downregulation of a critical effector, the Skp2 oncogene. Additionally, we observe significant induction of an interferon responsive viral defense gene signature as the result of epigenetic treatment. This gene signature has been shown to correlate with response to immune checkpoint blockade in the setting of metastatic melanoma. We propose that this combination of viral defense gene signature augmentation in conjunction with potent direct epithelial cancer cytotoxicity holds promise to be a more complete therapeutic paradigm for the treatment of NSCLC.
Citation Format: Michael Topper, Christin Hanigan, Michelle Vaz, Katherine Chiappinelli, Julin Justin, Lauren Murphy, Cynthia Zahnow, Stephen Baylin. Combination Azacitidine and histone deacetylase inhibition induces a multi factorial synergistic anti-tumor response in non-small cell lung cancer (NSCLC). [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 4653.
Abstract 4681: Oseltamivir phosphate completely ablates tumor refractoriness to conventional chemotherapeutics abraxane and gemcitabine in xenografts of tumors in mouse model of human pancreatic cancer
Authors: Szewczuk Myron R. 
Published: July 2016

Abstract
Pancreatic cancer, the fourth leading cause of cancer-related death worldwide, is highly aggressive and associated with a poor prognosis. Resistance to drug therapy, along with high rates of metastasis, contributes to the low survival rates in patients diagnosed with pancreatic cancer. Gemcitabine, a chemotherapeutic agent, is the current standard of care for patients with the disease. Although gemcitabine has higher success rates than any other chemotherapeutic in use, patients receiving gemcitabine still only have progression-free survival in the range of 0.9-4.2 months. Given the poor response rate to gemcitabine, pancreatic cancer cells develop rapid resistance to this drug. Here, we investigated the proof of concept for a reported entirely new anticancer drug, oseltamivir phosphate (OP), to overcome tumor refractoriness to gemcitabine and abraxane in heterotopic xenografts of pancreatic MiaPaCa-2 tumors growing in RAGxCγ double mutant mice. The data clearly indicate that mice treated with 50mg/kg abraxane alone (1x weekly, i.p.) at Day 33 post implantation slightly restrained tumor growth until Day70 at which time the tumor developed resistance to abraxane and rapidly increased in tumor volume and spread to the lungs. In contrast, abraxane in combination with OP 20mg/kg (3x weekly, i.p.) abrogated the tumor resistance to abraxane and impeded tumor growth and metastatic spread to the lung. Very interestingly, with comparable results to abraxane/OP, mice treated with 30mg/kg gemcitabine (1x weekly, i.p.) at Day31 post implantation developed tumor resistance at Day50 to gemcitabine and rapidly increased in tumor volume and spread to the lung. Gemcitabine in combination with 20mg/kg OP (3x weekly, i.p.) completely impeded the tumor growth, chemoresistance and spread to the lungs with long term survival at Day 240 with no relapse and metastasis. The significance of these findings is the first to show that OP in combination with standard, clinical chemotherapeutics can impede (a) human pancreatic tumor growth, (b) tumor neovascularization, (c) liver and lung metastases, and (d) tumor refractoriness to conventional chemotherapeutics, as well (e) significantly extending survival rates with no relapse and metastasis.
Citation Format: Myron R. Szewczuk. Oseltamivir phosphate completely ablates tumor refractoriness to conventional chemotherapeutics abraxane and gemcitabine in xenografts of tumors in mouse model of human pancreatic 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 4681.
Abstract 4695: Functional group elaboration of a low molecular weight fragment to yield the novel BET family bromodomain inhibitor ABBV-075
Authors: McDaniel Keith , Wang Le , Sheppard George , Fidanze Steve , Pratt John , Liu Dachun , Hasvold Lisa , Mantei Robert , Park Chang , Sarthy Aparna , Li Leiming , Albert Daniel H. , Lin Xiaoyu , Warder Scott , Faivre Emily , Bui Mai H. , Huang Xiaoli , Wilcox Denise , Wang Rongqi , Magoc Terry , Rajaraman Ganesh , Petros Andrew , Panchal Sanjay , Sun Chaohong , Fang Guowei , Elmore Steven W. , Rosenberg Saul , Shen Yu , Kati Warren 
Published: July 2016

Abstract
Phenotypic cell-based screening assays combined with affinity chromatography and mass-spectrometry identified the BET family of bromodomains as potential targets for blocking proliferation in a variety of cancer cell lines. Lead-finding investigations included screening a library of compounds with an average molecular weight of 225 for binding to the 13C-labeled 2nd bromodomain of BRD4 using 2-dimensional NMR. A pyridazinone fragment emerged from this effort that possessed weak binding affinity (Kd = 130 uM). The binding affinity was improved by roughly 100,000-fold through an X-ray structure enabled medicinal chemistry program that included moving to a pyrrolopyridone core along with judicious placement of additional functional groups. Antiproliferative potencies strongly correlated with potencies in a cell-based target engagement assay, suggesting that the antiproliferative effects resulted from the inhibition of BRD4/BET protein function. In vitro metabolite ID studies in rat liver microsomes helped identify sites of oxidative metabolism. The addition of fluorine atoms at these locations improved rat in vitro microsomal stability that translated to low in vivo clearance and high oral exposure in rat. The final molecule, ABBV-075, exhibited long half-lives and low unbound clearances in rat, mouse, dog and monkey. ABBV-075 demonstrated significant tumor growth inhibition in mouse flank xenograft studies representing diverse hematological and solid tumor malignancies and recently entered Phase I clinical studies.
Disclosures:
All authors are employees of AbbVie. The design, study conduct, and financial support for this research were provided by AbbVie. AbbVie participated in the interpretation of data, review, and approval of the publication.
Citation Format: Keith McDaniel, Le Wang, George Sheppard, Steve Fidanze, John Pratt, Dachun Liu, Lisa Hasvold, Robert Mantei, Chang Park, Aparna Sarthy, Leiming Li, Daniel H. Albert, Xiaoyu Lin, Scott Warder, Emily Faivre, Mai H. Bui, Xiaoli Huang, Denise Wilcox, Rongqi Wang, Terry Magoc, Ganesh Rajaraman, Andrew Petros, Sanjay Panchal, Chaohong Sun, Guowei Fang, Steven W. Elmore, Saul Rosenberg, Yu Shen, Warren Kati. Functional group elaboration of a low molecular weight fragment to yield the novel BET family bromodomain inhibitor ABBV-075. [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 4695.
Abstract 4704: The evaluation of INCB059872, an FAD-directed inhibitor of LSD1, in preclinical models of human small cell lung cancer
Authors: Lee Sang Hyun , Liu Xuesong Mike , Diamond Melody , Dostalik Valerie , Favata Margaret , He Chunhong , Wu Liangxing , Wynn Richard , Yao Wenqing , Hollis Gregory , Huber Reid , Scherle Peggy , Ruggeri Bruce 
Published: July 2016

Abstract
Methylated histone marks on H3K4 and H3K9 are generally coupled with transcriptional activation and repression, respectively. Altered levels of these histone methylation marks lead to abnormal gene expression and are associated with oncogenesis. Lysine specific demethylase 1 (LSD1) catalyzes demethylation of mono and di-methylated lysine 4 and 9 of histone H3 via an FAD-dependent redox-process. Deregulated LSD1 activity perturbs normal gene expression and can lead to cellular transformation. In particular, the function of LSD1 has been reported to maintain stem cell-like gene expression patterns in various cancers, most notably small cell lung cancer (SCLC), a cancer type that is characterized by a highly undifferentiated state and with high unmet medical need. INCB059872 is a potent, selective and orally bioavailable inhibitor of LSD1 that achieves inhibitory activity through the formation of covalent FAD-adducts. The effect of INCB059872 in SCLC cell lines was assessed in vitro and in vivo. In these studies, the proliferation of a panel of SCLC cell lines was inhibited by INCB059872, with EC50 values ranging from 47 to 377 nM. Non-tumorigenic cells, such as IL-2 stimulated T cells from normal donors, by contrast, were significantly less sensitive with IC50 values &gt; 10 μM. Oral administration of INCB059872 on once daily (QD) and alternative day (QoD) dosing regimens inhibited tumor growth in the NCI-H526 and NCI-H1417 human SCLC xenograft models. Consistent with previous reports, INCB059872 treatment in these models led to the induction of the FEZ1 and UMODL1 genes relative to vehicle-treated animals, as part of a gene signature in SCLC cell lines that is predictive of LSD1 responsiveness. Moreover, serum levels of the neuroendocrine marker pro-GRP were markedly reduced at all efficacious dosing regimens in the NCI-H1417 human SCLC xenograft model, suggesting that serum pro-GRP levels could be used as a surrogate pharmacodynamic marker of LSD1 inhibition. Currently, the efficacy of INCB059872 in combination with standard of care therapies for SCLC is under evaluation in these preclinical models. These data support the clinical evaluation of INCB059872 in patients with SCLC.
Citation Format: Sang Hyun Lee, Xuesong Mike Liu, Melody Diamond, Valerie Dostalik, Margaret Favata, Chunhong He, Liangxing Wu, Richard Wynn, Wenqing Yao, Gregory Hollis, Reid Huber, Peggy Scherle, Bruce Ruggeri. The evaluation of INCB059872, an FAD-directed inhibitor of LSD1, in preclinical models of human small cell lung 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 4704.
Abstract 4722: Selective inhibition of DNA methyltransferases and efficacy of novel DNMT inhibitors in leukemia xenografts
Authors: Nguyen Dat , Hollingshead Melinda , Rubinstein Larry , Doroshow James , Yang Sherry X. 
Published: July 2016

Abstract
Background. DNA methyltransferase (DNMT) 1 plays an important role in tumorigenesis and is responsible for maintenance and propagation of DNA methylation patterns, and DNMT3A and DNMT3B are involved in de novo DNA methylation. 4’-Thio-5-aza-2’-deoxycytidine (5-aza-T-dCyd) and 4’-thio-2’-deoxycytidine (T-dCyd) are novel DNMT inhibitors in development. In this investigation, we test the hypothesis that DNMTs are differentially modulated by DNMT inhibitors that may contribute to treatment efficacy. Methods. Animals (5 per group) bearing HL-60 leukemia cell xenografts were treated with saline or aza-T-dCyd at 2 mg/kg with and without 100 mg/kg tetrahydrouridine (ThU) for 5 days weekly for 2 weeks and cycle repeat after 9-day rest. Two other groups were dosed with T-dCyd at 4 mg/kg and decitabine at 0.75 mg/kg, respectively. Tumor growth was assessed by measuring tumor size. Expression of DNMT1, DNMT3A and DNMT3B was examined by immunohistochemistry in paraffin-embedded tumors resected at day 11. Results. Expression of DNMT1 was high, DNMT3B intermediate, and DNMT3A at low levels in saline control group. Significant growth delay was achieved in the aza-T-dCyd (86%) and aza-T-dCyd plus ThU cohorts (45%), compared with the controls. In the aza-T-dCyd treated xenografts, histological examination confirmed a significant reduction (77%) in tumor area (P = 0.002). Expression of DNMT1 and DNMT3B (n = 2 in aza-TdCyd group) was reduced in aza-T-dCyd cohort (P = 0.01 and P = 0.04) as well as aza-T-dCyd in combination with ThU group (P = 0.01 and P = 0.03). In contrast, no growth inhibition but decrease in DNMT3A and DNMT1 were observed by dosing with decitabine. There were neither delays for tumor growth nor changes of all three DNMTs by T-dCyd treatment with the dose administered. Conclusions. Aza-T-dCyd and aza-T-dCyd plus ThU treatments result in significant tumor growth inhibition in HL-60 leukemia xenografts. The anti-tumor activity is associated with simultaneous inhibition of the two drug targets — DNMT1 and DNMT3B. The preclinical results provide compelling evidence to advance aza-T-dCyd for clinical development and perhaps in the context of companion biomarker approach.
Citation Format: Dat Nguyen, Melinda Hollingshead, Larry Rubinstein, James Doroshow, Sherry X. Yang. Selective inhibition of DNA methyltransferases and efficacy of novel DNMT inhibitors in leukemia xenografts. [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 4722.
Abstract 4726: Inhibitors of histone deacetylase 1 reverse the immune evasion phenotype to enhance T-cell-mediated lysis of prostate and breast carcinoma cells
Authors: Gameiro Sofia R. , Malamas Anthony S. , Fantini Massimo , Tsang Kwong Y. , Ferrone Soldano , Hodge James W. 
Published: July 2016

Abstract
The clinical promise of cancer immunotherapy relies on the premise that the immune system can effectively recognize and eliminate tumor cells identified as non-self. However, tumors can evade host immune surveillance through multiple mechanisms, including epigenetic silencing of genes involved in antigen processing and immune recognition. Hence, there is an unmet clinical need to develop effective therapeutic strategies that can restore tumor immune recognition and thus promote long-lasting tumor control when combined with immunotherapy, such as immune checkpoint blockade and therapeutic cancer vaccines. Although epigenetic therapies have shown limited clinical benefit for patients harboring solid tumors, recent clinical reports suggest a strong potential for clinical synergy when combined with immunotherapy. We sought to examine the potential of clinically relevant exposure of prostate and breast human carcinoma cells to histone deacetylase (HDAC) inhibitors to reverse tumor immune escape to T-cell mediated lysis. Here we demonstrate that prostate and breast carcinoma cells are more sensitive to T-cell mediated lysis in vitro after clinically relevant exposure to epigenetic therapy with either the pan-HDAC inhibitor vorinostat or the class I HDAC inhibitor entinostat. This pattern of immunogenic modulation was observed against a broad range of tumor-associated antigens, such as CEA, MUC-1, PSA, and brachyury, and associated with augmented expression of multiple proteins involved in antigen processing and tumor immune recognition. Genetic and pharmacological inhibition studies identified HDAC1 as a key determinant in the reversal of carcinoma immune escape. Further, our findings suggest that the observed reversal of tumor immune evasion is driven by a response to cellular stress through activation of the unfolded protein response. This offers the rationale for combining HDAC inhibitors with immunotherapy, including therapeutic cancer vaccines.
Citation Format: Sofia R. Gameiro, Anthony S. Malamas, Massimo Fantini, Kwong Y. Tsang, Soldano Ferrone, James W. Hodge. Inhibitors of histone deacetylase 1 reverse the immune evasion phenotype to enhance T-cell-mediated lysis of prostate and breast carcinoma cells. [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 4726.