bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 2643: Discovery and characterization of a selective TrkA inhibitor for the treatment of TrkA-driven cancers
Authors: Tirunagaru Vijaya G. , Nagaswamy Kumaragurubaran , Mitra Sayan , Maddi Srinivas , Adluri Ram Sudheer , Joshi Hemant , Gupta Jang B.
Published: July 2016

Kinase gene fusions have been implicated as oncogenic drivers promoting cell survival and proliferation. TrkA gene fusions have been reported in a number of cancer types including lung, colorectal, papillary thyroid, sarcoma, cholangiocarcinoma and other tumors. We have identified novel, potent, selective and orally bioavailable TrkA inhibitors for the treatment of TrkA-driven cancers. One of the inhibitors, GVK-TrkI showed potent activity with an IC50 of 0.8 nM and 1.5 nM in the cell based assays for WT TrkA (AD293 cells expressing TrkA) and TPM3-NTRK1 fusion (KM12 cells) respectively. Potent activity of 12.5 nM IC50 was observed in TrkA Z-lyte kinase assay. Significant change in TrkA Z-lyte kinase IC50 was not observed at multiple ATP concentrations ranging from 100 uM to 1 mM suggesting non-ATP competitive mode of inhibition. Excellent selectivity (>1000x) was observed towards TrkB and TrkC in the cell based assays. GVK-TrkI inhibited TrkA autophosphorylation in a concentration dependent manner up to 24 h in KM12 cells in vitro. GVK-TrkI inhibited cell proliferation in KM12 cells with a GI50 of 34 nM while exhibiting no activity in cell lines without TrkA fusion. Comparable activity was observed in Ba/F3 cell line expressing MPRIP-NTRK1 fusion, demonstrating inhibition of TrkA driven cell proliferation irrespective of the N-terminal fusion with a different gene, MPRIP. In the KM12 xenograft model, treatment with GVK-TrkI at various doses and dosing regimens of 20 mpk bid, 50 mpk bid and 100 mpk qd resulted in dose dependent inhibition with almost 100% tumor growth inhibition (TGI) at 100 mpk qd with 3 out of 8 mice showing complete tumor regression. Besides, at 50 mpk in various dosing regimens of qd, bid and bid alternate day showed good correlation of TGI with compound exposure. GVK-TrkI was well-tolerated, causing no weight loss or death compared with vehicle control. Based on the evidence of ATP binding site mutations contributing to clinical resistance with kinase inhibitor drugs, GVK-TrkI is predicted to be effective as a second generation TrkA inhibitor with a non-ATP binding site mechanism compared to pan-Trk inhibitors currently being pursued in clinic. These results suggest that GVK-TrkI is an effective therapeutic option in TrkA driven cancers with TrkA gene fusions, activating mutations and cancers with NGF/TrkA overexpression resulting in constitutive activation of TrkA pathway.

Citation Format: Vijaya G. Tirunagaru, Kumaragurubaran Nagaswamy, Sayan Mitra, Srinivas Maddi, Ram Sudheer Adluri, Hemant Joshi, Jang B. Gupta. Discovery and characterization of a selective TrkA inhibitor for the treatment of TrkA-driven cancers. [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 2643.
Abstract 2652: Pan-cancer analysis of programmed death-ligand 1 (PD-L1) amplifications
Authors: Budczies Jan , Bockmayr Michael , Klauschen Frederick , Weichert Wilko , Denkert Carsten , Stenzinger Albrecht
Published: July 2016

PD-L1, located in the chromosomal region 9p28, is a ligand of programmed cell death protein 1 (PD-1) and has been described as immune checkpoint regulator that allows cancers to evade the host immune system. To stratify patients for treatment with PD-1 inhibitors, PD-L1 expression is currently intensively studied on RNA and protein levels. However, no comprehensive study of PD-L1 amplifications including many cancer types has been performed so far.

We investigated PD-L1 amplifications in eighteen cancer types that were copy number profiled, gene expression profiled and clinically characterized by the TCGA consortium: Acute Myeloid Leukemia (LAML), Bladder Urothelial Carcinoma (BLCA), Brain Lower Grade Glioma (LGG), Breast invasive carcinoma (BRCA), Cervical squamous cell carcinoma and endocervical adenocarcinoma (CESC), Colorectal adenocarcinoma (COADREAD), Glioblastoma multiforme (GBM), Head and Neck squamous cell carcinoma (HNSC), Kidney renal clear cell carcinoma (KIRC), Liver hepatocellular carcinoma (LIHC), Lung adenocarcinoma (LUAD), Lung squamous cell carcinoma (LUSC), Ovarian serous cystadenocarcinoma (OV), pancreatic adenocarcinoma (PAAD), Sarcoma (SARC), Skin Cutaneous Melanoma (SKCM), Stomach adenocarcinoma (STAD) and Uterine Corpus Endometrial Carcinoma (UCEC).

We found a diverse landscape of focal PD-L1 amplification, 9p chromosome arm amplifications and polysomy 9. Focal amplifications had the highest incidence in OV (10.7%), LUSC (9.8%), HNSC (8.6%), BLCA (8.3%), SARC (8.2%), CESC (7.1%), STAD (6.8%) and BRCA (5.3%). 9p amplifications were most frequently found in OV (12.6%), BLCA (7.4%), BRCA (6.8%) and LUAD (5.2%). Polysomy 9 had the highest incidence in COADREAD (14.0%), HNSC (13.6%), CESC (11.2%), SARC (9.4%) and STAD (7.2%), BLCA (5.9%) and GBM (5.5%). In a pooled analysis of focal and non-focal alterations, PD-L1 amplifications positively correlated with gene expression in nine cancer types and significantly (p < 0.05) shortened overall survival in five cancer types.

In summary, PD-L1 amplifications represent a frequent genetic alteration that occurs in many cancer types and could potentially be exploited for patient stratification and immune therapy.

Citation Format: Jan Budczies, Michael Bockmayr, Frederick Klauschen, Wilko Weichert, Carsten Denkert, Albrecht Stenzinger. Pan-cancer analysis of programmed death-ligand 1 (PD-L1) amplifications. [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 2652.
Abstract 2664: Eradication of neuroblastoma by suppressing the expression of a single long noncoding RNA
Authors: Tee Andrew E. , Liu Pei Y. , Milazzo Giorgio , Vandesompele Jo , Marshall Glenn M. , Perini Giovanni , Mestdagh Pieter , Dinger Marcel , Liu Tao
Published: July 2016

Neuroblastoma is the most common solid tumour in early childhood, and accounts for approximately 15% of all childhood cancer death. N-Myc gene amplification occurs in one quarter to one third of human neuroblastoma tissues, and the majority of patient with neuroblastoma due to N-Myc gene amplification die of the disease. We performed RNA sequencing experiments, and identified 5 transcripts, including RP1X, which were considerably differentially expressed between N-Myc gene amplified and non-amplified human neuroblastoma cell lines. Affymetrix microarray studies revealed that DEPD was one of the few genes considerably down-regulated in neuroblastoma cells after RP1X depletion. Chromatin immunoprecipitation assays showed that knocking-down RP1X expression reduced histone H3 lysine 4 trimethylation, a marker for active gene transcription, at the DEPD gene promoter. Depletion of RP1X or DEPD significantly reduced ERK protein phosphorylation, N-Myc protein phosphorylation at Serine 62, N-Myc protein stabilization, neuroblastoma cell proliferation and survival. Clonogenic assays showed that knocking-down RP1X with doxycycline completely abolished colony formation capacity of neuroblastoma cells stably transfected with doxycycline-inducible RP1X shRNA. Importantly, treatment with doxycycline in mice xenografted with neuroblastoma cells stably transfected with doxycycline-inducible RP1X shRNA, led to tumour eradication. In human neuroblastoma tissues from 600 neuroblastoma patients, high levels of RP1X gene expression correlated with DEPD gene expression and poor patient prognosis. In conclusion, this study identifies the novel long noncoding RNA RP1X as an important regulator of N-Myc protein stability and neuroblastoma tumourigenesis.

Citation Format: Andrew E. Tee, Pei Y. Liu, Giorgio Milazzo, Jo Vandesompele, Glenn M. Marshall, Giovanni Perini, Pieter Mestdagh, Marcel Dinger, Tao Liu. Eradication of neuroblastoma by suppressing the expression of a single long noncoding RNA. [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 2664.
Abstract 267: Preclinical investigation of the HSP90 inhibitor, ganetespib, in combination with FDA-approved cytotoxic agents for their potential anti-tumor effects on human neuroendocrine tumors
Authors: Wong Chung , Vosburgh Evan , Levine Arnold , Proia David , Xu Eugenia
Published: July 2016

The gastroenteropancreatic neuroendocrine tumor (GEP-NET) system is comprised of a heterogeneous group of tumors with increasing incidence. Current standard of care cytotoxic agents have limited efficacy, which necessitates the need for innovative therapeutic approaches. Heat shock protein 90 (HSP90) is overexpressed in a wide range of tumor types including human pancreatic neuroendocrine tumors (PanNETs). Ganetespib is a second-generation HSP90 inhibitor that is well tolerated in cancer patients (dosed into >1500 patients) and is currently being evaluated in several investigator sponsored clinical trials including acute myeloid leukemia (AML), ovarian cancer, breast cancer, and other tumor types.

Here, we show that ganetespib inhibits the proliferation of NET cells and induces apoptosis in vitro with potency comparable to another second-generation HSP90 inhibitor (NVP-AUY922), but with potency two- to seven-fold more than first generation inhibitors (17-AAG, IPI-504) in BON-1, CM and H727 cell lines, and thirty-fold more in QGP-1 cell line. In mice bearing PanNET tumor xenografts, single agent ganetespib reduced the growth of tumors without signs of toxicity. Tumors from ganetespib treated animals demonstrated reduced phospho-AKT and phospho-ERK expression, and elevated HSP70 expression, supportive of exposures necessary for functional activity. In an effort to identify clinically meaningful agents that could further potentiate the antitumor activity of ganetespib, we performed in vitro combination screens evaluating proliferation in four NET cell lines with ganetespib and forty FDA approved anticancer agents. Ganetespib showed synergistic effects when combined with inhibitors of mTOR, topoisomerase I or II, or DNA synthesis. Results from our ongoing in vivo combination studies with ganetespib and these three classes of anticancer agents will be presented.

Citation Format: Chung Wong, Evan Vosburgh, Arnold Levine, David Proia, Eugenia Xu. Preclinical investigation of the HSP90 inhibitor, ganetespib, in combination with FDA-approved cytotoxic agents for their potential anti-tumor effects on human neuroendocrine tumors. [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 267.
Abstract 2677: Unfolded protein response is required for EMT-driven metastasis by inducing CREB3L1
Authors: Feng Yuxiong , Jin Dexter X. , Gupta Piyush B.
Published: July 2016

Cancer initiates and progresses in the presence of a diversity of stresses ranging from nutrient deficiency, low oxygen supply to pH fluctuations. A set of stress response pathways, termed unfolded protein response (UPR), was evolved to maintain homeostasis of the endoplasmic reticulum (ER) from disruption by the above stressors. While it is broadly acknowledged that the UPR is involved in tumorigenesis, as tumor cells can employ the UPR as a critical survival strategy to grow and resist chemotherapy, the role of UPR in metastasis remains largely elusive. Epithelial-to-mesenchymal transition (EMT) is a cell transdifferentiation program frequently hijacked by cancer cells to migrate and invade. Here we showed cancer cells that have undergone an EMT employ the PERK-ATF4 branch of the UPR to drive metastasis, since loss of ATF4 abrogates the cell invasion upon an EMT. By conducting gene expression profiling, we found that the PERK-ATF4 pathway mediates the expression of a subset of the essential pro-invasion EMT-signature genes. In particular, CREB3L1, an ER-associated transcription factor (TF), is highly induced upon EMT in an ATF4-dependent manner. Knockdown of CREB3L1 effectively inhibits the EMT-driven invasion, while overexpression of CREB3L1 not only promotes invasion but also rescues the decrease of invasion caused by loss of ATF4. Mechanistically, CREB3L1 facilitates invasion through an ECM-FAK cascade. In breast cancer patients, the expression of CREB3L1 is significantly upregulated in breast cancer metastases compared to primary lesions, and predicts a poor prognosis. Most importantly, unlike other EMT-TFs, CREB3L1 could be inhibited by known chemicals, since the activation of CREB3L1 is mediated by the S1P- and S2P- dependent proteolysis. In an orthotopic breast cancer model, we found that chemical inhibition of CREB3L1 drastically suppresses lung metastasis. As a summary, we discovered that an ER stress-associated transcription factor CREB3L1 is required for cancer metastasis, and the susceptibility of CREB3L1 to chemical inhibition makes it a valuable target for drug development.

Citation Format: Yuxiong Feng, Dexter X. Jin, Piyush B. Gupta. Unfolded protein response is required for EMT-driven metastasis by inducing CREB3L1. [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 2677.
Abstract 2682: Sympathetic activation alters the bone vasculature: implication for osteotropic breast cancer metastasis
Authors: Mulcrone Patrick L. , Campbell J. Preston , Anbinder Ana Lia , Sterling Julie A. , Elefteriou Florent
Published: July 2016

Emotional stresses chronically activate the Hypothalamic-Pituitary-Adrenal axis and the sympathetic nervous system (SNS), and have been associated with the progression and recurrence of breast cancer, as well as with reduced survival of breast cancer patients. We observed that isoproterenol (ISO), a β1/2 adrenergic receptor (βAR) agonist used to mimic sympathetic activation, induced the expression of Vegfa in mouse bone in vivo and in osteoblast cultures in vitro. Because VEGF is pro-angiogenic, and tumor cells depend on the vasculature to form distant metastases, we hypothesized that SNS chronic activation may increase bone marrow vascular density via an effect on β2AR-expressing osteoblasts, thus promoting the possibility of metastatic breast cancer establishment in the skeleton. To address this question, we measured the formation of CD31+ vessels in femurs in vivo by histomorphometric analyses, following daily ISO treatment of adult mice for 6 weeks. Vessel number was significantly increased by ISO treatment in WT mouse femurs, and this effect was blunted in mice lacking the β2AR. Further supporting our hypothesis, we found that the conditioned media (CM) from MC3T3 osteoblasts treated with ISO augmented blood vessel formation in an ex vivo metatarsal assay as compared to the CM of PBS-treated osteoblasts. Lastly, the CM of ISO-treated MC3T3 osteoblasts promoted primary bone endothelial cell tube formation, and inhibition of Vegf:Vegfr2 interaction with the antibody mcr84 reduced this formation. These results suggest that the effect of chronic stress on metastatic breast cancer cell establishment in the skeleton may be mediated in part due to changes in the bone microenvironment, specifically an increase in osteoblastic VEGF that changes host bone marrow vascular density.

Citation Format: Patrick L. Mulcrone, J. Preston Campbell, Ana Lia Anbinder, Julie A. Sterling, Florent Elefteriou. Sympathetic activation alters the bone vasculature: implication for osteotropic breast cancer metastasis. [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 2682.
Abstract 2690: A novel antibody-drug conjugate directed to the ALK receptor tyrosine kinase demonstrates efficacy in models of neuroblastoma
Authors: Sano Renata , Krytska Kateryna , Larmour Colleen , Ligon Gwenda F. , Lillquist Jay S. , Cucchi Ulisse , Orsini Paolo , Rizzi Simona , McMahon Gerald , Alvarado Diego , Mosse Yael P.
Published: July 2016

Activated ALK by mutation or amplification is a validated therapeutic target in a subset of patients with high-risk neuroblastoma, and tyrosine kinase inhibitors are being developed to abrogate ALK signaling (Bresler et al, 2014). Native ALK is expressed on the surface of the majority of neuroblastoma tumors, but not on normal tissue, giving it properties of a tumor antigen. We hypothesized that ALK-targeted antibodies may be useful in neuroblastoma as single-agent immunotherapy or in combination with small-molecule ALK inhibitors - especially where mutations reduce kinase inhibitor sensitivity. In this work, an anti-ALK monoclonal antibody (anti-ALK2) was conjugated to a cytotoxic agent (ALK2-ADC) and its anti-tumor activity was investigated in a panel of extensively characterized human neuroblastoma cell lines (n = 10) harboring wild type and mutant ALK. Cell surface ALK was quantified using flow cytometry and revealed differential antigen expression. Using in vitro growth inhibition assays, there was evidence for a dose-dependent cytotoxicity to neuroblastoma cells at subnanomolar concentrations that correlated with ALK expression and was independent of underlying mutation status. In order to evaluate the therapeutic potential of ALK2-ADC in vivo, mice bearing Felix-patient-derived xenograft (PDX) tumors, containing the third most common ALK mutation (R1245C), were used to demonstrate that ALK2-ADC led to a significant reduction in tumor growth compared to unconjugated antibody and a control ADC (p<0.0001). Although ALK2-ADC binds potently to mouse ALK as well as human ALK, doses of up to 10 mg/kg in the rodent model appeared to be well tolerated with no overt toxicity noted. Additional in vivo studies are ongoing to assess the antitumor potential of the ADC in a broader range of ALK-expressing neuroblastoma models. Thus, targeting human ALK-expressing with an ALK antibody-drug conjugate demonstrated early signs of favorable efficacy and tolerability supporting future development of this approach as a potential novel therapeutic for patients with neuroblastoma.

Citation Format: Renata Sano, Kateryna Krytska, Colleen Larmour, Gwenda F. Ligon, Jay S. Lillquist, Ulisse Cucchi, Paolo Orsini, Simona Rizzi, Gerald McMahon, Diego Alvarado, Yael P. Mosse. A novel antibody-drug conjugate directed to the ALK receptor tyrosine kinase demonstrates efficacy in models of neuroblastoma. [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 2690.
Abstract 2711: Spatiotemporal progression patterns in metastatic lung cancer treated with bevacizumab
Authors: Mason Jeremy M. , Newton Paul K. , In Gino K. , Lin Sonia , Kuhn Peter , Nieva Jorge J.
Published: July 2016

We describe a Markov chain mathematical model of lung cancer progression based on a longitudinal dataset of 722 lung cancer patients. Specifically, we investigate the patterns of metastatic spread in lung cancer and how the VEGF inhibitor, bevacizumab, alters these metastatic patterns. Stochastic models were used to simulate metastatic spread by means of random walk processes on directed graphs. We created spatiotemporal diagrams of cancer progression to analyze the differences between patients treated and not treated with bevacizumab. Patients with squamous lung cancer or brain metastases at baseline were ineligible for bevacizumab and excluded from analysis. Our results demonstrated that not only does bevacizumab extend survival, but it also alters patterns of metastatic spread. Patients treated with bevacizumab were characterized by greater heterogeneity in their pathways of metastatic progression, compared to those patients not treated with bevacizumab, which showed more homogeneity in their pathways. Furthermore, we quantify this spread and characterize metastatic sites as ‘spreaders’ and ‘sponges’ based on their probability of spreading the disease.

Citation Format: Jeremy M. Mason, Paul K. Newton, Gino K. In, Sonia Lin, Peter Kuhn, Jorge J. Nieva. Spatiotemporal progression patterns in metastatic lung cancer treated with bevacizumab. [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 2711.
Abstract 2713: Combination of PLK1 and PI3K inhibitors shows strong synergy in anaplastic thyroid cancer
Authors: Yilmaz Emrullah , Orlacchio Arturo , Di Cristofano Antonio
Published: July 2016

Anaplastic thyroid cancer (ATC) is the most aggressive thyroid cancer with median of 6 months of survival from diagnosis. Molecular alterations are well defined recently. p53 mutations, and activation of PI3K, RAS and BRAF are among the most common alterations. PLK1 overexpression has also been identified in ATC.

We have previously shown that PLK1 inhibitors are effective in ATC cell lines. However PLK1 inhibition in cell lines with PI3K activation resulted in escaping growth arrest and subsequent mitotic catastrophe through mitotic slippage. Since the PI3K activation is common in ATC, there is risk of generating polyploid, genetically unstable cell populations by targeting these tumors with a PLK1 inhibitor. So we tested the effect of combining PLK1 and PI3K inhibitors in ATC cell lines.

We combined PLK1 inhibitor BI6727 and PI3K inhibitor BKM120 and measured the cell viability using Alamar Blue. Combination of these two drugs resulted in significant synergy in mouse derived PTEN deleted ATC cell lines. We observed the same synergy in the human ATC cell lines with PIK3CA mutations.

BI6727 showed significant G2/M arrest in the cell lines. The combination two drugs enhanced the G2/M arrest. In a low dose that the single drugs showed no inhibition in cell cycle, combination resulted in G2/M arrest.

We treated the cells with a dual PI3K and PLK1 inhibitor Rigosertib. Although we have seen some sensitivity of the cells with PIK3CA mutation, the cell lines with PTEN were strongly resistant to Rigosertib.

Our results show that combination of PLK1 and PI3K inhibitors is an effective treatment for ATC cells with PI3K activation. This combination results in cell cycle arrest suggesting the role of using combination therapies in this aggressive cancer.

Citation Format: Emrullah Yilmaz, Arturo Orlacchio, Antonio Di Cristofano. Combination of PLK1 and PI3K inhibitors shows strong synergy in anaplastic thyroid 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 2713.
Abstract 2717: Reintroduction of DAXX suppresses alternative lengthening of telomeres in osteosarcoma
Authors: Driest Kathryn E. , Waterfall Joshua J. , Walker Robert L. , Pineda Marbin A. , Abaan Ogan , Zhu Yuelin J. , Wang Yonghong , Ester Corbin D. , Davis Sean R. , Bilke Sven , Meltzer Paul S.
Published: July 2016

The unlimited proliferative capacity of cancer cells is closely linked to maintenance of their telomeres, which shorten with each cell division in normal cells. Cancer cells are able to maintain telomere length by multiple mechanisms, including activation of telomerase and the recombination based alternative lengthening of telomeres (ALT) pathway. ALT is prevalent in osteosarcoma, with approximately 50% of osteosarcoma cases using ALT for telomere maintenance. Mutations in the ATRX/DAXX chromatin remodeling complex and histone H3.3 correlate with activation of the ALT pathway in several tumor systems. While loss of ATRX is a frequent event in osteosarcoma tumors, alterations of DAXX have not been reported. We characterized the telomere maintenance mechanisms utilized by 11 osteosarcoma cell lines. Of these, 45% (5/11) were ALT positive and 45% (5/11) were telomerase positive. One cell line possessed features of both telomere maintenance mechanisms. Among ALT positive osteosarcoma cell lines, we observed frequent loss of ATRX expression (4/5) and a previously unreported translocation resulting in disruption of DAXX. The translocation abolishes recruitment of DAXX to nuclear PML bodies and prevents normal DAXX function. By reintroducing full length DAXX, we were able to suppress telomere maintenance by ALT as evidenced by multiple assays including loss of C-circles and ALT-associated PML bodies, thus demonstrating that continued DAXX deficiency is necessary for maintenance of the ALT mechanism. Suppression of ALT by DAXX reintroduction did not result in compensatory activation of telomerase. This first demonstration of ALT suppression by DAXX supports a mechanistic connection between loss of the ATRX/DAXX chromatin remodeling complex and telomere maintenance by ALT. Understanding this relationship may uncover vulnerabilities specific to ALT tumors that could potentially lead to the development of targeted therapies for diverse cancers that depend on the ALT pathway.

Citation Format: Kathryn E. Driest, Joshua J. Waterfall, Robert L. Walker, Marbin A. Pineda, Ogan Abaan, Yuelin J. Zhu, Yonghong Wang, Corbin D. Ester, Sean R. Davis, Sven Bilke, Paul S. Meltzer. Reintroduction of DAXX suppresses alternative lengthening of telomeres in osteosarcoma. [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 2717.
Abstract 272: Metformin enhances the anti-prostate cancer activity of abiraterone and enzalutamide
Authors: Xie Yi , Wang Linbo , Hussain Arif
Published: July 2016

The standard treatment for advanced castration sensitive prostate cancer (CSPC) is androgen deprivation therapy (ADT), generally in the form of suppression of gonadally produced androgens via medical or surgical castration. The selective inhibitor of androgen biosynthesis Abiraterone (Abi), and the androgen receptor (AR) antagonist Enzalutamide (MDV3100), are second line hormonal therapies used to treat PC patients failing ADT. However, these drugs provide treatment response for a limited duration of time due to the development of resistance to them. Included among the mechanisms leading to resistance to ABI or MDV is the expression of the AR variant AR-V7. Metformin, a widely used oral anti-diabetic drug, has been reported to reduce prostate cancer mortality in PC patients with type II diabetes. In this study, we explored the effects of ABI, MDV and metformin in a pre-clinical model of PC. Both Abi and MDV inhibited cell proliferation and the expression of prostate specific antigen (PSA) in androgen-sensitive LNCaP cells. However, neither induced cell death, and in fact MDV appeared to actually inhibit apoptosis in LNCaP cells. Both agents increased AR and AR-V7 expression, which in part may account for development of resistance to ABI or MDV. In contrast, metformin inhibited AR, AR-V7 and PSA expression in a dose-dependent manner, and induced apoptotic cell death in PC cells. Metformin, in combination with ABI or MDV, further enhanced apoptosis and inhibited expression of PSA than it did as single agent. Interestingly, at near physiological concentrations metformin induced apoptosis in a caspase-independent manner rather than by a caspase-dependent apoptotic program that is reported to occur with high doses of metformin. In conclusion, Abi or MDV inhibits AR signaling and PC cell proliferation, but also induces AR and AR-V7 expression. Metformin decreases AR and AR-V7 expression and induces apoptotic cell death. The combination of metformin with androgen biosynthesis/AR inhibitors results in caspase-independent apoptotic cell death in addition to inhibition of both cell proliferation and AR signaling. Further studies will be needed to evaluate the clinical efficacy of these combination treatments in patients with PC.

Citation Format: Yi Xie, Linbo Wang, Arif Hussain. Metformin enhances the anti-prostate cancer activity of abiraterone and enzalutamide. [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 272.
Abstract 2727: LOX is a novel mitotic spindle-associated protein essential for mitosis
Authors: Boufraqech Myriem , Wei Darmood , Weyemi Urbain , Zhang Lisa , Quezado Martha , Kalab Petr , Kebebew Electron
Published: July 2016

Lysyl oxidase (LOX) is a copper-dependent amine oxidase that plays a critical role in the biogenesis of connective tissue matrices. LOX is highly expressed in aggressive cancers; has been associated with a shorter survival and regulates cancer progression in a variety of human malignancies. Here, we report a new function of LOX in mitosis in anaplastic thyroid cancer cell line (THJ-16T), breast cancer cell line (MDA-MB231) and HeLa cells. We show that LOX co-localizes to mitotic spindles from metaphase to telophase, and p-H3(Ser10)-positive cells harbor strong LOX staining. Further, purification of mitotic spindles from synchronized cells show that LOX fails to bind to microtubules in the presence of nocodazole, whereas paclitaxel treated samples showed enrichment in LOX expression suggesting that LOX binds to stabilized microtubules only. Functional studies of LOX depletion resulted in decreased cellular proliferation, G2/M cell cycle arrest, and formation of gigantic nuclei. Further, LOX knockdown led to reduced p-H3(Ser10), cyclin B1, CDK1, and Aurora B expression. Lastly, LOX knockdown significantly increased sensitivity of cancer cells to chemotherapeutic agents that target microtubules and this effect was synergistic. Our results show identify a novel function of LOX in cancer cell mitosis, and that loss of LOX expression in cancer cells can enhanced effects of anti-microtubules agents used in cancer therapy.

Citation Format: Myriem Boufraqech, Darmood Wei, Urbain Weyemi, Lisa Zhang, Martha Quezado, Petr Kalab, Electron Kebebew. LOX is a novel mitotic spindle-associated protein essential for mitosis. [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 2727.
Abstract 2739: Carnosic acid induces cell cycle arrest of B16F10 cells and synergizes with carmustine and lomustine in vitro and in vivo
Authors: Lin Kun-I , Lin Chih-Chien , Chen Ming-Feng , Chen Chang-Han , Shiu Li-Yen
Published: July 2016

Carnosic acid (CA), one of the purified components of rosemary, has shown anti-inflammatory, chemo-preventive, and anticancer activities. In this study, we treated melanoma cell line B16F10 with CA and detected the anticancer effects. After 24-hour treatment, CA decreased cell proliferation rate, wound healing activity, and inhibited colony formation of B16F10. Additionally, CA induced G0/G1 cell cycle arrest, up-regulated p21 expression, and down-regulate cyclin E, cyclin D and CDK4 expression. Carmustine (BCNU) and Lomustine (CCNU) are used in clinical treatment of melanoma. To assay the combinational effects of CA and BCNU or CCNU, B16F10 cells were treated with CA, BCNU, CCNU alone, or CA combined with BCNU or CCNU. Our results showed, BCNU and CCNU arrested cell cycle at G2/M phase after 24-hour treatment. Dramatically, CA enhenced BCNU- and CCNU-induced cell cycle arrest at G2/M phase, and decreased cyclin B1 and p-CDK1 expresion. In the in vivo xenograft model, B16F10 cells (5×105) were inoculated subcutaneously in C57BL/6 mice, and the tumor grew for one week. The mice were divided into six groups and provided different treated strategies: control, CA (50 mg/kg) alone, BCNU (50 mg/kg) alone, CCNU (25 mg/kg) alone, CA combined with BCNU, and CA combined with CCNU. After two-week treatment, compared with control group, CA had better treated effects than BCNU or CCNU. Compared with CA, BCNU or CCNU treatment alone, the combined strategies inhibited the tumor growth in melanoma mice model more effectively. Furthermore, BCNU and CCNU treatment in melanoma mice caused high values of aspartate aminotransferase (AST) and alanine aminotransferase (ALT). However, CA significantly decreased AST and ALT values caused by BCNU and CCNU in combined trestment group. Therefore, CA is more safe and effective than BCNU and CCNU, and the combined treatment strategies of CA and BCNU or CCNU result in an increased antitumor efficacy. CA may be suitable for translation to future clinic.

Citation Format: Kun-I Lin, Chih-Chien Lin, Ming-Feng Chen, Chang-Han Chen, Li-Yen Shiu. Carnosic acid induces cell cycle arrest of B16F10 cells and synergizes with carmustine and lomustine in vitro and in vivo. [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 2739.
Abstract 2742: USP37 promote oncogenesis by stabilizing protein involved in DNA damage repair pathway and provides a novel way to modulate Chk1 activity
Authors: singh mayank , Burrows Amy C. , Dickson Andrew , Summers Matthew
Published: July 2016

Dysregulation of the Ubiquitin proteasome system (UPS), which comprises nearly 1000 different components is associated with many aspects of oncogenesis and has emerged as a novel therapeutic target. We have previously shown that USP37 (Ubiquitin specific peptidase 37) antagonizes the tumor suppressor APCCDH1and it promotes S phase entry while data from other groups have shown that it stabilizes oncoproteins, such as c-Myc. We have found USP37 protein levels to be high in many cancerous cell lines as compared to untransformed cells and it appears to help tumor survive the high level of replication stress associated with oncogene expression. It was found that USP37 over expression confers survival advantage to cancer cells while its depletion enhances chemo sensitization in response to variety of replication stresses. USP37 over expressing cells were able to resolve γ-H2AX foci much more effectively then the wild type or cells in which USP37 was depleted. Our data indicate that USP37 binds and stabilizes the active form of CHK1 as evident by its protein levels when USP37 over expressing or depleted cells were exposed to replication stress. Mechanistically, our analyses indicate that USP37 stabilizes CHK1 by its deubiquitination, preventing its degradation. As CHK1 has been pursued as a therapeutic target with limited success our work defines a novel way to modulate activity of CHK1 while simultaneously targeting multiple oncogenes and thereby providing a rationale to evaluate USP37 inhibitor over CHK1 inhibitor as a potential therapeutic target in different cancers.

Citation Format: mayank singh, Amy C. Burrows, Andrew Dickson, Matthew Summers. USP37 promote oncogenesis by stabilizing protein involved in DNA damage repair pathway and provides a novel way to modulate Chk1 activity. [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 2742.
Abstract 2761: Cellular consequences of human tyrosyl-DNA phosphodiesterase I dysregulation
Authors: Cuya Selma M. , Regal Kellie M. , Van Waardenburg. Robert C.A.M.
Published: July 2016

Tyrosyl-DNA phosphodiesterase I (Tdp1) is a highly conserved eukaryotic DNA repair enzyme that catalyzes the resolution of 3’ and 5’ phospho-DNA adducts. Tdp1 has been implicated in the repair of DNA topoisomerase I (Topo1)-DNA covalent complexes reversibly stabilized by camptothecins (CPTs) such as the FDA approved CPT derivatives topotecan and irinotecan. Tdp1 utilizes a two-step catalytic cycle that centers on the formation of an obligatory Tdp1-DNA covalent complex (Tdp1-cc) through its nucleophilic histidine (Hisnuc), resulting in dissociation of the adduct, while its general acid/base histidine (Hisgab) mediates Tdp1 dissociation. A Tdp1Hisgab to Arg (H493R) mutant stabilizes the Tdp1-cc and is associated with autosomal recessive ataxia SCAN1. Alternative substitutions of Hisgab or substitutions of the Hisnuc transforms yeast Tdp1 into a potent toxin via stabilization of Tdp1-cc. We propose that stabilization of this Tdp1-DNA covalent complex is a potential novel therapeutic anti-cancer strategy. As proof-of-concept, we analyzed two catalytic Hisgab (H493R or H493N) mutants and one Hisnuc (H263A) mutant of hTdp1 in HEK293 cells. Doxycycline-induced expression of Tdp1H263A, Tdp1H493R, and Tdp1H493N mutant enzymes induced Tdp1-dependent cytotoxicity without additional genotoxic stress. Utilizing two different immuno-assays, we validated that the observed Tdp1-dependent toxicity correlates with stabilization of their enzyme-DNA covalent complex. Moreover, all of these Tdp1 catalytic mutants show reduced catalytic activity compared to wild type hTdp1, but they do not all show a stabilized Tdp1-cc in this in vitro assay. This indicates a significant difference between in vitro Tdp1 activity and cellular Tdp1 activity, which is most likely due to the difference in substrate; a small oligonucleotide with a 3’phospho-tyrosyl modification versus covalent complex of full length Topo1 with genomic DNA. However, these results confirm our previous yeast studies: Stabilization of the Tdp1-cc converts a DNA repair enzyme into a cellular toxin, which constitutes a potential novel therapeutic strategy to treat cancer. In addition, we are comparing schedule dependent ‘drug’-combinations of our toxic Tdp1 mutant expression with topotecan, etoposide (targets Topo2-cc) and cisplatin to evaluate the potential therapeutic value of this novel Tdp1 targeted strategy.

This work is in part supported by the ADDA, UAB ACS-IRG, and DOD OCRP WX81WH-15-1-0198.

Citation Format: Selma M. Cuya, Kellie M. Regal, Robert C.A.M. Van Waardenburg. Cellular consequences of human tyrosyl-DNA phosphodiesterase I dysregulation. [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 2761.
Abstract 2764: Detection of early gastric cancer with Sox17 DNA methylation analysis of gastric washes
Authors: Watanabe Yoshiyuki , Oikawa Ritsuko , Yamamoto Hiroyuki , Itoh Fumio
Published: July 2016

Aim: Although minimal invasive treatment is widely accepted for early stage of gastric cancer (EGC), we still do not have any appropriate risk markers to detect residual neoplasia and some potential of recurrence. We previously reported that aberrant DNA methylation is an early and frequent process in gastric carcinogenesis and could be useful for detection of gastric neoplasia (Gastroenterology 2009, Tumor Biology 2011). Our goal is to verify the potency of our three selected candidate genes (Sox17, MINT25, miR34) as a treatment marker for EGC. Method: We conducted a multicenter, prospective study using selected three candidate genes (Sox17, MINT25 and miR34) by Methylated CpG Island Amplification Microarray (MACAM) based analysis and analyzed the DNA methylation levels before and after endoscopic resection (ER) for EGC using gastric washes. We statistically analyzed sensitivity, specificity and AUC with DNA methylation levels of before / after ER and information of recurrent cases in 2 years. Results: 352 EGC cases were registered and endoscopically removed. 182 cases could followed endoscopically for 2 years (51.7%). Sensitivity, specificity and AUC were as follows. Sox17 (70.0%, 48.1%, 0.646), MINT25 (70.0%, 35.2% 0.555), miR34 (65.0%, 49.4%, 0.578). Conclusion: We have developed a new methodology for gastric cancer detection by DNA methylation in gastric washes. It is easy and useful for early detection of recurrence after endoscopic treatment in GCa patients.

Citation Format: Yoshiyuki Watanabe, Ritsuko Oikawa, Hiroyuki Yamamoto, Fumio Itoh. Detection of early gastric cancer with Sox17 DNA methylation analysis of gastric washes. [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 2764.
Abstract 2770: DERL3 hypermethylation alters rhabdomyosarcoma cell metabolism
Authors: Llinas Pere , Lopez Paula , Esteller Manel
Published: July 2016

Physiological cellular activity requires a precise control of the proteome. However, cancer cells have a distorted protein profile. It is likely that intrinsic defects in protein homeostasis participate in human tumorigenesis, such as alterations in de novo protein synthesis, or defects in protein degradation. In this last case, the ubiquitin (Ub) proteasome system (UPS) targets a variety of proteins, including functional proteins that are no longer needed. Without appropriate protein homeostasis maintained by the UPS, healthy cells can undergo malignant transformation, and this observation has been therapeutically exploited by the development of proteasome inhibitors as anticancer agents. Many of the cytoplasm UPS-degraded proteins are retrotranslocated from the endoplasmic reticulum (ER). In this regard, ER possesses a quality control mechanism, termed the ER-associated degradation mechanism (ERAD), that is induced in response to ER stress by a transcriptional program, known as the unfolded protein response (UPR), which leads to the accelerated degradation of unfolded proteins. Within the ERAD pathway, the Derlin proteins play a critical role. It has been proposed that Derlins form an export channel in the membrane of the ER through which the ERAD substrates pass to reach the proteasome.

A previous study in our lab has shown that DERL3 silencing by DNA methylation deregulate SLC2A1 (GLUT1) degradation, promoting the Warburg effect. SLC2A1 is a key glucose receptor up-regulated in most solid tumors, allowing cancer cells to get the glucose they need for tumor progression.

In this study we use an embryonic rhabdomyosarcoma cell line as a model to find out the role of DERL3 in these tumors, as the percentage of promoter hypermethylation is these tumors is approximately 60%. Rhabdomyosarcoma (RMS) is one of the leading causes of cancer related deaths among children, being the histological variant of embryonic rhabdomyosarcoma the most common soft tissue sarcoma of childhood and adolescence, with 350 cases per year in USA.

The restoration of DERL3 expression in vitro promotes GLUT1 degradation and GLUT4 up-regulation, becoming cells sensitive to insulin. Moreover, it has been shown that DERL3 confers sensitivity against an ERAD related drug, Eeyarestatin I, opening a new approach for RMS treatment. All together, these initial findings highlight the role of DERL3 in RMS metabolism.

Citation Format: Pere Llinas, Paula Lopez, Manel Esteller. DERL3 hypermethylation alters rhabdomyosarcoma cell metabolism. [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 2770.
Abstract 2771: Epigenetic regulation of the cocaine and amphetamine regulated transcript (CART) in cancer
Authors: Connor Kate , Das Sudipto , Moran Bruce , Mulrane Laoighse , Gallagher William M. , O’Connor Darran
Published: July 2016

The cocaine and amphetamine regulated transcript (CART) is well documented in the central nervous system for its role in appetite regulation and reward pathways. In recent studies CART has been proven to be a poor prognostic marker in lymph node-negative, estrogen receptor (ER)-positive breast cancer patients, and has also been shown to be associated with worse survival in small bowel carcinoid tumours. The regulation of CART in these different cancer types however remains largely unknown. The presence of a large CpG island in the putative promoter region and the lack of expression of CART in many cancer cell lines suggest a possible epigenetic mechanism of suppression.

A panel of various cancer cell lines (breast, colorectal, endometrial and ovarian) were assessed for endogenous CART expression via western blot and RT-PCR. Cells were then treated with forskolin and leptin; agents which have been previously shown to induce CART expression in the CNS. Cells were also treated with CART conditioned media, which has been previously shown to be the only factor capable of inducing CART expression. Treatment was carried out with varying doses of two DNA methyltransferase inhibitors, 5-Aza-2′-deoxycytidine and RG108, followed by examination of CART expression post treatment. Bisulfite sequencing of the promoter region of CART was performed in all cell lines and a small selection of formalin fixed paraffin embedded (FFPE) tissue samples. Whole methylome sequencing was carried out to confirm this promoter region of CART and study the global effects of treatment with epigenetic modifiers and CART peptide.

Assessment of a collection of cell lines via western blot has shown CART expression to be negative across the panel. Moreover, treatment with forskolin and leptin did not result in re-expression of CART. Treatment with 5-Aza-2′-deoxycytidine has however resulted in increased CART mRNA levels, and subsequent bisulfite sequencing of the promoter region of CART has revealed dense methylation at the CpG island. Treatment with CART conditioned media may also induce promoter demethylation and subsequent re-expression of CART. Collectively, this data suggests the potential involvement of DNA methylation in the regulation of CART.

Citation Format: Kate Connor, Sudipto Das, Bruce Moran, Laoighse Mulrane, William M. Gallagher, Darran O’Connor. Epigenetic regulation of the cocaine and amphetamine regulated transcript (CART) in 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 2771.