bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 3622: Novel SMAC-mimetic birinapant demonstrates antitumor activity in human head and neck cancer models exhibiting alterations in cell death pathways
Authors: Carlson Sophie , Eytan Danielle , Snow Grace , Schiltz Stephen , Mohan Suresh , Saleh Anthony , Cornelius Shaleeka , Coupar Jamie , Van Waes Carter , Chen Zhong
Published: August 2015

The Cancer Genome Atlas (TCGA) uncovered frequent and prognostically important genomic alterations of cell death signaling molecules, including chromosome 11q13/22 FADD and/or BIRC2 (cIAP1) amplifications, or CASP8 mutations, in distinct head and neck squamous cell carcinoma (HNSCC) subtypes. Consistent with TCGA, we found increased FADD and/or cIAP1 expression in a panel of 11 HNSCC cell lines. Overexpression of cIAP1 has been implicated in resistance to standard of care therapies that act through the induction of apoptosis. Birinapant, a novel SMAC-mimetic that targets and promotes degradation of cIAPs, inhibited cell density and sensitized multiple HNSCC lines to death agonists TNF or TRAIL, which was reversible by inhibitors of caspase-dependent apoptosis and/or RIPK1-mediated necroptosis. In vivo, birinapant significantly inhibited tumor growth and prolonged host survival in two FADD/cIAP1-overexpressing xenograft models, UMSCC 46 and 11B. Remarkably, birinapant combined with radiation treatment, an inducer of TNF, cured animals bearing UM-SCC-46 xenografts. These results suggest that birinapant generates strong synergy with radiotherapy in HNSCC harboring cell death pathway genomic alterations linked to worse prognosis.

Citation Format: Sophie Carlson, Danielle Eytan, Grace Snow, Stephen Schiltz, Suresh Mohan, Anthony Saleh, Shaleeka Cornelius, Jamie Coupar, Carter Van Waes, Zhong Chen. Novel SMAC-mimetic birinapant demonstrates antitumor activity in human head and neck cancer models exhibiting alterations in cell death pathways. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3622. doi:10.1158/1538-7445.AM2015-3622
Abstract 3625: Expression of CRBN binding protein AGO2 plays important roles for myeloma cell growth
Authors: Xu Qinqin , Hou Yuexian , Langlais Paul , Erickson Patrick , Zhu James , Shi Changxin , Luo Moulun , Zhu Yuanxiao , Mandarino Lawrence , Stewart Keith , Chang Xiu-Bao
Published: August 2015

Immunomodulatory drugs (IMiDs) are therapeutically active compounds that bind to the E3 ubiquitin ligase substrate recruiter cereblon (CRBN) and induce many cellular responses, including cytotoxicity. We had found that the expression of CRBN in multiple myeloma (MM) cells provided the basis for their responses to IMiDs. In this report, we have identified argonaute 2 (AGO2) as a new member of CRBN-downstream binding protein and found that: 1) the steady-state levels of CRBN in IMiD-sensitive cells are significantly higher than in IMiD-resistant cells; 2) the steady-state levels of AGO2 in IMiD-sensitive cells are significantly less compared to IMiD-resistant cells, suggesting that CRBN plays a role in regulating AGO2. AGO2 is a component of microRNA (miRNA)-induced silencing complexes and plays an important role in miRNA maturation and function. The matured miRNAs are considered as key regulators of almost all cellular pathways. Treatment of IMiD-sensitive MM cells with lenalidomide, an IMiD, significantly increased CRBN, decreased both AGO2 and miRNAs and inhibited cell growth. In contrast, although treatment of IMiD-resistant MM cells with lenalidomide moderately increased CRBN and decreased both AGO2 and miRNAs, this treatment did not significantly inhibit cell growth. However, silencing of AGO2 with small hairpin RNA significantly decreased both AGO2 and miRNAs and inhibited cell growth regardless of whether the cells are sensitive or resistant to IMiDs. Therefore, AGO2 could be considered as a new drug target for overcoming IMiDs resistance in MM cells.

Citation Format: Qinqin Xu, Yuexian Hou, Paul Langlais, Patrick Erickson, James Zhu, Changxin Shi, Moulun Luo, Yuanxiao Zhu, Lawrence Mandarino, Keith Stewart, Xiu-Bao Chang. Expression of CRBN binding protein AGO2 plays important roles for myeloma cell growth. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3625. doi:10.1158/1538-7445.AM2015-3625
Abstract 3635: Histone demethylase NDY1/KDM2B as a driver of survival and proliferation of normal and neoplastic mast cells
Authors: Foltopoulou Parthena , Pfau Raymond , Betancur-Boissel Monica , AbdelMageed Manar , Tsichlis Philip N. , McNiel Elizabeth A.
Published: August 2015

Proliferative disorders of mast cells exhibit a range of clinical behavior from benign cutaneous forms to aggressive systemic mastocytosis and mast cell leukemia. While these disorders are rare in people, they are among the most common malignancies in the dog, a circumstance that provides a useful model for an orphan disease. Growth of both normal and neoplastic mast cells is driven by c-kit (CD117), a tyrosine kinase receptor for stem cell factor. Ligand-independent, constitutive activation of c-kit via mutation is a common feature of mastocytic neoplasia. Therefore, tyrosine kinase inhibitors (TKIs) that target c-kit have activity in aggressive mastocytosis in people and in dogs. However, resistance to c-kit targeted TKIs is common in both species, highlighting a need for other therapeutic targets.

Our data indicates that chromatin modification may be important in mast cell biology. Specifically, we have shown that the JmjC domain lysine 36 specific histone H3 demethylase, NDY1/KDM2B, supports the proliferation and immortalization of bone-marrow derived mast cells. It is well known that NDY1/KDM2B is a driver of hematopoietic transformation and is associated with malignant progression in certain solid tumors (breast, pancreatic and urothelial carcinoma). Therefore, we investigated the effects of knockdown of NDY1/KDM2B in neoplastic human and canine mast cells in vitro and in xenografts. Our data demonstrate that this knockdown inhibits proliferation and induces apoptosis in vitro and inhibits tumor growth in vivo. Therefore, targeting therapy of NDY1/KDM2B or downstream effectors in mast cell tumors could be a beneficial addition to the existing therapeutic modalities.

Supported by grants from the Morris Animal Foundation (D14CA) and NIH (R01CA109747).

Citation Format: Parthena Foltopoulou, Raymond Pfau, Monica Betancur-Boissel, Manar AbdelMageed, Philip N. Tsichlis, Elizabeth A. McNiel. Histone demethylase NDY1/KDM2B as a driver of survival and proliferation of normal and neoplastic mast cells. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3635. doi:10.1158/1538-7445.AM2015-3635
Abstract 3639: Design and development of a novel series of orally active, selective PI3K-p110β/δ inhibitors for the treatment of solid and hematological cancers
Authors: Shuttleworth Stephen J.
Published: August 2015

The phosphatidylinositide 3-kinases (PI3Ks) have emerged as important therapeutic targets for the treatment of solid and hematological malignancies. For solid tumor therapy, the majority of clinical activity has largely centered on pan-class I (p110α, β, δ and γ) inhibitors with limited selectivity, or pan-class I/mTOR dual inhibitors, whereas targeting p110δ and p110γ has been the main focus for hematological cancer treatment in the clinic. Our research at Karus in the PI3K arena has been based upon the emerging role of p110β and p110δ in PTEN-deficient solid and hematological tumorigenesis, and in the emerging role of individual PI3K isoforms in tumor immunotherapy. We have designed and developed a uniquely-selective series of orally-active molecules that inhibit the p110β/δ isoforms, and which display high degrees of specificity over protein kinases and other lipid kinases. Moreover, a spectrum of p110β/δ selectivity has been achieved in this series, which has facilitated interrogation of preferred isoform inhibition profiles required to confer tumor growth inhibition; additionally, by tuning selectivity over the other class I isoforms, elimination of the mechanism-related toxicities associated with the pan-class I inhibitors currently in the clinic can be realized, making such agents potentially more conducive to combination therapy. In vitro and in vivo therapy data for advanced lead compounds will be disclosed.

Citation Format: Stephen J. Shuttleworth. Design and development of a novel series of orally active, selective PI3K-p110β/δ inhibitors for the treatment of solid and hematological cancers. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3639. doi:10.1158/1538-7445.AM2015-3639
Abstract 3642: Structure enabled design of inhibitors of the mitotic kinase MPS1
Authors: Innocenti Paolo , Woodward Hannah , Cheung Kwai_Ming J. , Naud Sébastien , Solanki Savade , Westwood Isaac M. , Faisal Amir , Hayes Angela , Schmitt Jessica , Baker Ross , Matijssen Berry , Burke Rosemary , Eccles Suzanne A. , Raynaud Florence I. , Linardopoulos Spiros , Blagg Julian , van Montfort Rob L M , Hoelder Swen
Published: August 2015

MPS1 (also known as TTK), is a dual-specificity protein kinase that is essential for the proper attachment of chromosomes to the mitotic spindle. MPS1 expression is elevated in a variety of human cancers and is correlated with higher histological grade, aggressiveness and poor patient survival. It has been also shown that basal, PTEN-deficient and triple negative breast cancers are sensitive to MPS1 inhibition. These data together provide strong support for selective antitumour action of MPS1 inhibitors in human cancers. Here we report the discovery of pyridopyrimidines as a new class of inhibitors of MPS1 exploring a hybridization approach. Rapid structure based optimisation of the initial hits led to highly potent, selective and ligand efficient compounds. We will discuss our initial design approach and the structural features that are critical for potent biochemical and cellular inhibition as derived from SAR and co-crystal structures. Furthermore, we will report pharmacokinetic and in vivo properties of selected compounds and comment on our strategy to optimise this series towards preclinical candidates.

Citation Format: Paolo Innocenti, Hannah Woodward, Kwai_Ming J. Cheung, Sébastien Naud, Savade Solanki, Isaac M. Westwood, Amir Faisal, Angela Hayes, Jessica Schmitt, Ross Baker, Berry Matijssen, Rosemary Burke, Suzanne A. Eccles, Florence I. Raynaud, Spiros Linardopoulos, Julian Blagg, Rob L M van Montfort, Swen Hoelder. Structure enabled design of inhibitors of the mitotic kinase MPS1. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3642. doi:10.1158/1538-7445.AM2015-3642
Abstract 3644: Identification of existing targeted agents that inhibit NTRK and ROS1 in lung cancer
Authors: Chong Curtis , Ercan Dalia , Bahcall Magda , Capelletti Marzia , Gray Nathanael , Janne Pasi
Published: August 2015

All patients with oncogenic driver mutations in non-small cell lung cancer (NSCLC) who are treated with a targeted agent will eventually develop resistance. In an effort to identify inhibitors of NTRK1 and ROS1, which are inappropriately activated in NSCLC, we created and screened a library of existing targeted drugs against BaF3 cells transformed with these oncogenes. This screen identified the FDA-approved drug cabozantinib as a potent inhibitor of CD74-ROS1 (IC50 = 9 nM), including the crizotinib-resistant mutants G2032R (IC50 = 26 nM) and L2026M (IC50 = 11 nM), with no inhibition of the parental BaF3 cells (IC50 > 10 μM). AP26113, a dual ALK/EGFR inhibitor undergoing phase I/II clinical trials, also potently inhibited CD74-ROS1 (IC50 = 4 nM), including the crizotinib-resistant mutants G2032R (IC50 = 206 nM) and L2026M (IC50 = 84 nM), with weak inhibition of the parental BaF3 cells (IC50 > 1 μM). Both cabozantinib and AP26113 inhibited ROS1 autophosphorylation and downstream ERK activation in CD74-ROS transformed BaF3 cells and in the ROS1-rearranged NSCLC cell line HCC78. The FGFR3 inhibitor dovitinib, which is in phase III clinical trials for renal cell carcinoma, potently inhibited NTRK1 compared to parental BaF3 cells (IC50 = 69 nM vs > 1 μM), and blocked NTRK1 autophosphorylation and ERK activation. While acquired resistance to targeted therapies is a major clinical problem, this study highlights other existing agents that may overcome resistance, and identifies several promising candidates for clinical trials.

Citation Format: Curtis Chong, Dalia Ercan, Magda Bahcall, Marzia Capelletti, Nathanael Gray, Pasi Janne. Identification of existing targeted agents that inhibit NTRK and ROS1 in lung cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3644. doi:10.1158/1538-7445.AM2015-3644
Abstract 3653: Structure-based study to overcome cross-reactivity of novel androgen receptor inhibitors
Authors: Li Huifang , Lallous Nada , Dalal Kush , Leblanc Eric , Ban Fuqiang , Ciesielski Fabrice , Rennie Paul S. , Cherkasov Artem
Published: August 2015

The mutation-driven transformation of clinically used anti-androgens into agonists of human androgen receptor (AR) represents a major challenge in the current treatment of prostate cancer (PCa). To address this problem, we have developed a novel class of AR inhibitors targeting the DNA-binding domain (DBD) of the receptor, which is distanced from the mutations-prone androgen binding site (ABS) in the ligand-binding domain (LBD) of the AR, targeted by all conventional antiandrogens. While many members of the developed phenyl-thiazol-2-yl-morpholine series demonstrated potent sub-micromolar inhibition of the wild-type AR, some compounds also exhibited an undesired partial agonistic effect toward the T877A mutated form of the receptor, implying their cross-interaction with the AR ABS.

To study the molecular basis of the cross-reactivity, we have solved the T877A mutated form of the AR LBD in complex with one developed compound exhibiting such unwanted partial agonism. Based on the resolved crystal structure, we have identified critical protein-ligand interactions and conformational changes in wild-type and T877A forms of AR that drive observed agonistic effects. The identified structural basis has further been used to modify the scaffold of developed AR DBD binders to eliminate their cross-reactivity toward T877A mutated AR LBD. In particular, the replacement of the phenyl ring with less hydrophobic heterocycles resulted in a series of inhibitors that did not demonstrate affinity toward ABS or exhibit an undesired agonistic effect on AR. This study provides insights into the development of AR inhibitors with high specificity, which may help overcome the mutation-driven resistance of anti-AR drugs in the treatment of PCa.

Citation Format: Huifang Li, Nada Lallous, Kush Dalal, Eric Leblanc, Fuqiang Ban, Fabrice Ciesielski, Paul S. Rennie, Artem Cherkasov. Structure-based study to overcome cross-reactivity of novel androgen receptor inhibitors. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3653. doi:10.1158/1538-7445.AM2015-3653
Abstract 3656: PARG inhibition: development of novel compounds and a biomarker strategy to determine cell line sensitivity in breast cancer
Authors: Waddell Ian D. , James Dominic , Smith Kate , Holt Sarah , Acton Ben , Fairweather Emma , Hamilton Niall , Hamilton Nicola , Hitchen James , Huttom Colin , Jordan Allan , McGonagle Alison , Small Helen , Stowell Alex , Waszkowycz Bohdan , Ogilvie Donald
Published: August 2015

Background: DNA single strand breaks (SSBs) are the most common type of damage occurring in cells. Poly (ADP ribose) polymerase (PARP) binds to SSBs and auto-ribosylates itself using NAD+ as a substrate. PARG is the only enzyme known to efficiently catalyse the hydrolysis of O-glycosidic linkages of ADP-ribose polymers and exists (unlike PARP) as a single gene. We have developed novel inhibitors of PARG and here we describe our efforts to understand their sensitivity against a range of cell lines

Methods: A robust and detailed screening cascade for small molecule inhibition of PARG has been developed. Active compounds are tested in cells for PAR chain persistence and for cytotoxicity using a 3-day HeLa assay. In addition, suitable compounds were then evaluated for their physico-chemical properties and their in vivo PK profiles determined. Compounds with the desired PK properties are subsequently profiled in tumour bearing mice to determine their pharmacodynamic effect before progressing to efficacy studies.

Results: We have developed nM PARG inhibitors that are highly selective against ARH3 and PARP1and these derivatives show potent activity in cells. We have designed a breast cancer cell panel against which our compounds have been tested. Our initial bioinformatics analysis suggests that deficiency of a known tumour suppressor confers sensitivity to PARG inhibition.

Conclusions: We have developed two drug-like series of PARG inhibitors that block the breakdown of PAR chains in cells after exogenous DNA damage by methylating agents. These tool compounds are potent, selective and have pharmacokinetic and pharmacodynamics properties that have allowed us to explore their anti-tumour potential. The discovery of a tumour suppressor profile indicating cell line sensitivity will aid the about identification of patient populations that will potentially benefit from PARGi therapies.

Citation Format: Ian D. Waddell, Dominic James, Kate Smith, Sarah Holt, Ben Acton, Emma Fairweather, Niall Hamilton, Nicola Hamilton, James Hitchen, Colin Huttom, Allan Jordan, Alison McGonagle, Helen Small, Alex Stowell, Bohdan Waszkowycz, Donald Ogilvie. PARG inhibition: development of novel compounds and a biomarker strategy to determine cell line sensitivity in breast cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3656. doi:10.1158/1538-7445.AM2015-3656
Abstract 3657: Preclinical evaluation of water-soluble pyrrolo[3,2-d]pyrimidines as single agents with tubulin and multiple receptor tyrosine kinase inhibition and as antitumor agents
Authors: Shah Khushbu , Gangjee Aleem , Pavana Roheeth , Nicholas Dybdal-Hargreaves F. , Mooberry Susuan
Published: August 2015

Multiple classes of microtubule targeting agents have been identified and these include the Vinca alkaloids and colchicine (microtubule-destabilizers) and taxanes (microtubule-stabilizers). Although tubulin targeting agents are some of the most successful drugs used in the treatment of a wide range of malignancies, multidrug resistance due to overexpression of P-glycoprotein (Pgp) and/or βIII-tubulin can severely limit their clinical efficacy. Antitubulin agents like paclitaxel and other taxanes, due to poor water solubility, are formulated with polyethoxylated castor oil which can cause hypersensitivity reactions and require prolonged administration time. Recently, we reported water-soluble pyrrolo[3,2-d]pyrimidine analogs acting as antitubulin agents that circumvent these drawbacks. These analogs also exhibit potency comparable to erlotinib in cancer cell lines overexpressing epidermal growth factor receptor (EGFR) and to that of sunitinib in cancer cell lines overexpressing vascular endothelial growth factor receptor-2 (VEGFR2) and platelet derived growth factor receptor-β (PDGFRβ), in addition to inhibiting tubulin. Promising evidence for the clinical success of combination chemotherapy using multiple RTK inhibitors with antitubulin agents suggests that these dual acting compounds would serve as a single entity with both these activities. To explore the activity of these dual RTK/tubulin inhibitors, compound AG165 was evaluated in in vitro and in vivo xenograft models. In vitro AG165 inhibited the growth of MDA-MB-435 cells with an IC50 of 8.8 nM, comparable to paclitaxel. The compound is also active in paclitaxel resistant cancer cells overexpressing βIII-tubulin or Pgp, thus overcoming two important mechanisms associated with clinical resistance to paclitaxel. Compound AG165 (subcutaneous doses of 75 mg/kg x 7, cumulative dose 525 mg) showed significant (p<0.001) inhibition of tumor growth 15 days after treatment initiation. AG165 caused recoverable weight loss without any evidence of adverse effects. In this study, we have identified a water-soluble, dual acting RTK/ tubulin inhibitory agent that address some critical limitations of existing therapies and demonstrates in vivo antitumor effects with an acceptable toxicity profile.

Citation Format: Khushbu Shah, Aleem Gangjee, Roheeth Pavana, Dybdal-Hargreaves F. Nicholas, Susuan Mooberry. Preclinical evaluation of water-soluble pyrrolo[3,2-d]pyrimidines as single agents with tubulin and multiple receptor tyrosine kinase inhibition and as antitumor agents. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3657. doi:10.1158/1538-7445.AM2015-3657
Abstract 366: A novel transcript variant of androgen receptor identified in circulating tumor cells from castration-resistant prostate cancer patients as a potentially prognostic biomarker
Authors: Kang Zhigang , Shah Avani , Yu Yunkai , Zhu Yuelin , Bhagat Ali Asgar , Zhao Kyra , Wu Andrew , Gao James , Madan Ravi , Gulley James , Dahut William , Meltzer Paul , Cao Liang
Published: August 2015

Circulating tumor cells (CTCs) are rare cancer cells in the bloodstream thought to have a key role in cancer metastasis. There are enormous interests in their analysis for castration-resistant prostate cancer (CRPC) due to their tendency to metastasize to bone. In this study, we applied a surface marker-independent microfluidic device for CTCs capture and retrieval that is based on cell size and deformability. Our device was able to capture 90% and recover 30% of tumor cells in spike experiments. We also developed and validated assays capable of detecting the transcript levels of selected molecular markers in single cells prepared with C1TM Single-Cell AutoPrep System. Blood samples drawn from 34 CRPC patients and 10 primary prostate cancer patients (PPC) were preceded for CTC isolation and molecular characterization. We found that 73% CRPC patients and 10% PPC patients were positive for EpCAM, and only about half of the EpCAM-positive CRPC cases were PSA or AR positive. It is interesting that while there is a strong association between AR and PSA expression in CTC samples, there is no correlation between AR or PSA transcripts in CTCs and serum PSA protein levels in CRPC patients. The positive detection of AR or PSA, but not EpCAM is statistically associated with poor prognosis of the CRPC patients. Very intriguingly, we identified a novel androgen receptor (AR) transcript variant -ARv from four CRPC patients’ CTCs. This ARv lacks a 554bp sequence region in the ligand binding domain (LBD), resulting in a loss of the entire LBD. Clinical data analysis revealed that the ARv is significantly associated with worse survival of CRPC patients (p<0.0001). In vitro functional studies showed this novel ARv is constitutively active in the absence of testosterone. Our findings suggest that this AR variant might contribute to the late stage progression of the diseases and could be used as a potential indicator for alternative therapies. In summary, our new fluidic device is capable of isolating CTC to enable molecular marker analysis, providing value in prognosis and guidance to therapy.

Citation Format: Zhigang Kang, Avani Shah, Yunkai Yu, Yuelin Zhu, Ali Asgar Bhagat, Kyra Zhao, Andrew Wu, James Gao, Ravi Madan, James Gulley, William Dahut, Paul Meltzer, Liang Cao. A novel transcript variant of androgen receptor identified in circulating tumor cells from castration-resistant prostate cancer patients as a potentially prognostic biomarker. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 366. doi:10.1158/1538-7445.AM2015-366
Abstract 3661: Development of novel small-molecule inhibitors of ETS oncoproteins as anti-prostate cancer agents
Authors: Tian Xiaohong
Published: August 2015

Currently advanced prostate cancer is treated by suppressing androgen receptor (AR) signaling. Since AR could be activated via multiple mechanisms, inhibition of one or two of these mechanisms could be initially effective, but drug resistance can rapidly develop due to kick-in of other AR-activating mechanisms, resulting in lethal castration-resistant prostate cancer (CRPC). The therapeutic effects of all of the currently available AR-targeting agents are short-lived. To achieve long lasting therapeutic effect for prostate cancer, it appears we need to get out of the box of AR. Here, we propose to develop chemical inhibitors of oncogenic protein ERG, which is an ETS transcriptional factor. The rationale for inhibiting ERG as a possible treatment for prostate cancer has two folds: i) ERG plays a critical role in prostate cancer initiation and progression, and ii) Half of all prostate cancer patients are TMPRSS2-ERG fusion positive, which result in high level of ERG oncoprotein. ERG is a transcriptional factor that directly regulates EZH2, oncogene c-Myc and tumor suppressor Nkx3.1 and many other targets in prostate cancer. ERG cooperates with PI3K/AKT and AR in tumor initiation. ERG knockdown inhibits tumor growth in xenograft of VCaP cells. To date, accumulated studies in patients and experimental models have indicated that ERG overexpression as a result of TMPRSS2-ERG fusion plays a critical role in prostate cancer initiation and progression.

However, ERG protein has no obvious functional sites or enzymatic activity to be inhibited and is considered ‘undruggable’. In contrast to such view, our laboratory has recently discovered a novel chemical inhibitor of ERG by combining virtual screening and reporter assay. We have built a structural model of ERG DBD and identified a putative binding-site for virtual screening study. We discovered a novel compound, which substantially inhibits ERG-dependent reporter activity in HEK293 cells and inhibits expression of ERG-regulated genes, such as EZH2 and c-Myc, in VCaP cells. We further showed that our compound inhibits proliferation of VCaP cells, and disrupts association of ERG with its essential coactivator PARP1 by co-IP assay. Surface Plasmon Resonance (SPR) analysis has confirmed that our compound has direct binding with recombinant ERG protein. As recent studies indicated that advanced prostate cancer with TMPRSS2-ERG fusion have substantial higher tendency to metastasize to lymph nodes, ERG inhibitors could be an effective therapeutics to prevent this progression. Importantly, ERG inhibitors could be effective therapeutics for advanced prostate cancer.

Citation Format: Xiaohong Tian. Development of novel small-molecule inhibitors of ETS oncoproteins as anti-prostate cancer agents. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3661. doi:10.1158/1538-7445.AM2015-3661
Abstract 3662: Design and development of a novel series of HDAC6-selective inhibitors for the treatment of hematological and solid tumors
Authors: Shuttleworth Stephen J.
Published: August 2015

Inhibition of the zinc-dependent histone deacetylase (HDAC) family of enzymes has been pursued as a clinical strategy in cancer for many years. HDACs regulate the expression and activity of numerous proteins involved in both cancer initiation and cancer progression; by removal of acetyl groups from histones, HDACs create a non-permissive chromatin conformation that prevents the transcription of genes that encode proteins involved in tumorigenesis. The current landscape of HDAC-targeting therapeutics has, however, been dominated by pan-inhibitors that regulate the activity of most, if not all, of the HDAC family members which, through dysregulation of expression of a myriad of genes, has led to agents with undesirable toxicities and narrow therapeutic margins. Recently, however, attention has begun to turn to the role of specific HDAC isoforms in tumorigenesis and, in turn, the development of more selective therapeutics. HDAC6 has emerged as a particularly interesting target as it plays an essential role in aggresomal protein degradation: specifically, HDAC6 binds polyubiquitinated misfolded proteins and recruits misfolded protein cargo to dynein motors for transport to aggresomes. Cells deficient in HDAC6 fail to clear these misfolded protein aggregates from the cytoplasm, cannot form aggresomes properly, and are hypersensitive to the accumulation of misfolded proteins, which leads to activation of apoptosis. Further, recent evidence has emerged of HDAC modulating immune-related pathways in solid tumors, notably regulating PDL-1 expressions through STAT3 modulation. This presentation will outline the design and development of a new class of highly-potent, selective and orally-active HDAC6 inhibitors with the potential in the treatment of multiple tumor types. Uniquely, this series of compounds has been designed such that selectivity levels for HDAC6 over other isoforms can be finely regulated, enabling the investigation of preferred levels of HDAC6 specificity for therapy, and opening possibilities for broader combination modalities in a clinical setting.

Citation Format: Stephen J. Shuttleworth. Design and development of a novel series of HDAC6-selective inhibitors for the treatment of hematological and solid tumors. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3662. doi:10.1158/1538-7445.AM2015-3662
Abstract 3666: Synthesis and evaluation of itraconazole analogues for hedgehog pathway inhibition
Authors: Pace Jennifer , Hadden M. Kyle
Published: August 2015

The hedgehog (Hh) pathway is a developmental signaling pathway that plays a key role in embryonic development. While the pathway is generally quiescent during adult life, dysregulation of the Hh pathway can lead to cell proliferation and tumor growth. This abnormal Hh signaling is typically responsible for tumors associated with basal cell carcinoma (BCC) and medulloblastoma (MB) and inhibiting the Hh pathway is a valid target to develop novel chemotherapeutic agents. Most Hh inhibitors identified to date target the protein smoothened (SMO), a crucial component of the Hh pathway. Vismodegib is a SMO inhibitor that was recently approved by the FDA for the treatment of advanced BCC. However, there has been an emergence of resistance to Vismodegib; this resistance is a result of a point mutation in SMO. This occurrence of Vismodegib-resistant SMO mutations highlights the therapeutic need for new Hh pathway inhibitors. Itraconazole (ITZ), a well-known antifungal agent, was recently determined to be a potent inhibitor of the Hh pathway in vitro and in vivo; ITZ was also found to be a potent inhibitor of wild type SMO and Vismodegib-resistant SMO. ITZ is well-characterized and there is a good understanding of its potential side effects. This well-known safety profile makes ITZ a desirable drug candidate. Our ongoing studies on the ITZ scaffold are focused on exploring the regions of ITZ that are required for potent Hh pathway inhibition. The design, synthesis, and preliminary in vitro evaluation of these ITZ analogues will be reported herein.

Citation Format: Jennifer Pace, M. Kyle Hadden. Synthesis and evaluation of itraconazole analogues for hedgehog pathway inhibition. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3666. doi:10.1158/1538-7445.AM2015-3666
Abstract 3667: Synthesis and biological evaluation of vitamin D3 analogues as selective Hedgehog pathway inhibitors
Authors: Maschinot Chad A. , Hadden Kyle
Published: August 2015

Constitutive signaling of the Hedgehog (Hh) pathway has been linked to the development of a variety of cancers, specifically basal cell carcinoma (BCC) and medulloblastoma (MB). In recent years, vitamin D3 (VD3) was identified as an inhibitor of the Hh pathway. However, studies indicated that it is non-selective and activates canonical vitamin D signaling through the Vitamin D Receptor (VDR). One of the focuses of our lab is the development of VD3 analogues that will result in increased potency and selectivity for the Hh pathway. Previous studies indicated that the northern region of VD3 maintained approximately 95% of the inhibitory activity associated with intact VD3 with minimal activation of canonical vitamin D signaling. In initial SAR studies of the A-ring motif, the incorporation of a phenolic A-ring motif with an ester linkage to Grundmann's alcohol proved to be a potent, selective inhibitor. Utilizing a phenolic A-ring motif, SAR studies have continued with the development of the next generation of VD3-based analogues. Progress towards the next generation of analogues as well as results of biological studies will be described herein.

Citation Format: Chad A. Maschinot, Kyle Hadden. Synthesis and biological evaluation of vitamin D3 analogues as selective Hedgehog pathway inhibitors. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3667. doi:10.1158/1538-7445.AM2015-3667
Abstract 3673: High-density lipoprotein-like nanoparticles target SR-B1 and inhibit the cellular uptake of melanoma-cell derived exosomes
Authors: Plebanek Michael P. , Matov Alexandre , Mautharasan Kannan , Gatlin Jesse , Thaxton C. Shad
Published: August 2015

Exosomes play a crucial role in the progression of cancer through the transport of a variety molecular cargo, including proteins, lipids, and nucleic acids, to and from cells as a means of intercellular communication. Unraveling mechanisms of exosome-cell interactions may open avenues for studying cellular communication and lead to new therapies. Cellular exosome uptake depends on cholesterol-rich membrane microdomains called lipid rafts. Non-specific depletion of lipid raft cholesterol reduces cellular exosome uptake; however, to our knowledge, no targeted mechanism of inhibiting cellular exosome uptake has been reported. Scavenger receptor type B-1 (SR-B1) localizes to lipid rafts, and is a high-affinity receptor for cholesterol-rich high-density lipoproteins (HDL). SR-B1 is an intriguing therapeutic target because it is upregulated in many different cancers due to the high need for cholesterol of rapidly dividing cancer cells. Therefore, we hypothesized that specific targeting of SR-B1 and modulation of cholesterol flux through this receptor with biomimetic HDL-like nanoparticles (HDL NPs) would disrupt cellular exosome uptake. As a model, we explored exosomes derived from melanoma cells as they have been shown to promote angiogenesis and immunosuppression both crucial events in melanoma progression. Melanoma exosomes have also been shown to actively prepare metastatic sites, creating a suitable microenvironment allowing for the development of metastasis. Because of this, targeting exosomes and intercellular signaling could be beneficial for the treatment of metastatic melanoma. Using a variety of techniques including confocal microscopy, flow cytometry and automated image analysis, data demonstrate that HDL NPs specifically target SR-B1 in lipid rafts in melanoma cells and modulate cholesterol flux through this receptor. This leads to a clustering of SR-B1 at the cell membrane and potent inhibition of the cellular uptake of melanoma cell-derived exosomes.

Citation Format: Michael P. Plebanek, Alexandre Matov, Kannan Mautharasan, Jesse Gatlin, C. Shad Thaxton. High-density lipoprotein-like nanoparticles target SR-B1 and inhibit the cellular uptake of melanoma-cell derived exosomes. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3673. doi:10.1158/1538-7445.AM2015-3673
Abstract 3684: Nanoparticle-encapsulated piperine and piperlongumine inhibit breast cancer cell growth and metastatic activity
Authors: Ghassemi-Rad Javad , Hoskin David W.
Published: August 2015

Breast cancer is the second leading cause of cancer-related deaths among women in Canada and the United States. Metastatic disease is the primary cause of death, despite recent advances in breast cancer treatment strategies and personalized medicine. Novel anti-cancer therapeutics are therefore urgently needed to increase the lifespan of breast cancer patients and prevent metastasis. Piperine (PIP) and piperlongumine (PL), two of the major alkaloids in pepper spices, show inhibitory effects on breast cancer cell growth in vivo and in vitro; however, their lipophilicity has restricted possible clinical application. The encapsulation of these phytochemicals in biodegradable nanoparticles is predicted to increase their water solubility and bioavailability. The goal of this study was first, to optimize a method for the preparation of PIP- and PL-containing polymeric nanoparticles, and second, to explore the inhibitory effects of nanoparticle-encapsulated PIP and PL on breast cancer cell growth and metastatic activity. In contrast to the single oil-in-water emulsion method, PIP- and PL-nanoparticles prepared by the thin-film hydration method were more spherical and showed a uniform size distribution. PIP- and PL- containing nanoparticles decreased the viability of MDA-MB-231 and MDA-MB-468 triple-negative breast cancer cells to the same extend as free PIP and PL. In addition, a noncytotoxic concentration of PIP- and PL-containing nanoparticles inhibited the in vitro migration and invasion of triple-negative breast cancer cells. These findings demonstrate that the encapsulation of PIP and PL within polymeric nanoparticles is possible without compromising the bioactivity of these phytochemicals. PIP- and PL-nanoparticles therefore warrant further investigation in mouse models of breast cancer to establish their utility in the treatment of breast cancer.

Citation Format: Javad Ghassemi-Rad, David W. Hoskin. Nanoparticle-encapsulated piperine and piperlongumine inhibit breast cancer cell growth and metastatic activity. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3684. doi:10.1158/1538-7445.AM2015-3684
Abstract 3687: A novel computational platform technology (VOLVOX™) for designing anticancer supramolecular therapeutics
Authors: Pandey Prithvi Raj , Sengupta Shiladitya , Roy Sudip
Published: August 2015

Current chemotherapy approaches are limited by suboptimal pharmacology. For example, only a fraction of drug administered reaches the tumor. While drug delivery platforms, such as ADCs or nanoparticles, aim to address this limitation by aiming to enhance targeted tumor delivery, these too are limited by drug loading and stability. Here we describe the development of a computational platform technology, VOLVOX, for designing anticancer supramolecular therapeutics. Supramolecular therapeutics evolve as a result of supramolecular assembly of molecular building blocks, thereby altering the PK/PD profile of the building blocks, while increasing drug loading, stability and anti-tumor efficacy. Specifically, VOLVOX envisages interaction of drug candidates with lipid bilayers using molecular simulations, generating information on packing the right excipients in the lipid bilayer. This method is applicable in loading wide range of excipients or drugs having different chemical compositions governed by hydrophilicity and hydrophobicity, shape (geometry/symmetry) and size, and in varying concentrations. This method is applicable for particle based simulation technique at different length and time scale (e.g., all atomistic molecular dynamics (MD), Coarse Grained MD, or Mesoscale MD). As proof of this platform technology, we present development of a novel taxane and a PI3K targeting supramolecular therapeutic.

Citation Format: Prithvi Raj Pandey, Shiladitya Sengupta, Sudip Roy. A novel computational platform technology (VOLVOX™) for designing anticancer supramolecular therapeutics. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3687. doi:10.1158/1538-7445.AM2015-3687
Abstract 3689: Comparative oncology drug discovery for Osteosarcoma in dogs and humans
Authors: Fulbright Joy M. , Neville Kathleen , Broward Melinda , Bruns Tyce A. , Roy Anuradha , McDonald Peter , Ottomeyer Megan , Thamm Douglas H. , Iwakuma Tomoo
Published: August 2015

Introduction: The purpose of this study was to identify FDA approved drugs that initiate cell death or growth arrest in canine and human osteosarcoma (OS) cell lines in vitro followed by confirmation of anticancer activity in these cell lines. The ultimate objective of this comparative oncology project is to identify promising agents for the treatment of osteosarcoma in dogs and humans, a disease in which survival rates have remained low and stagnant for the last three decades.

Procedures: A library of 2,328 FDA approved drugs was screened for activity in 2 canine and 2 human OS cell lines, as well as in 1 corresponding normal cell line. Cell viability was measure using the Cell Titer-Glo™ Luminescent Cell Viability Assay (Promega). FDA approved drugs meeting pre-determined screening criteria for activity, selectivity, and potency were selected for confirmatory studies. Effects on cell proliferation were confirmed using cell counting using trypan blue exclusion performed over a 10 day period. Effects on cell cycle and apoptosis were performed using propidium iodide staining and flow cytometry.

Summary: Nine FDA approved drugs were identified based on activity and selectivity. Auranofin, a FDA approved rheumatoid arthritis agent, was selected for cell proliferation and cell cycle evaluation due to its IC50 value in control cells in comparison to OS cell lines. Auranofin displayed cytostatic effects in canine and human OS cell lines at low doses and drugs appeared to induce G2 arrest in treated cells.

Conclusions: Auranofin is an FDA approved drug that demonstrates promising, selective anticancer activity in canine and human OS cell lines. The next steps are to determine whether this agent possesses additive or synergistic activity in combination with anticancer agents that have already demonstrated clinical activity in dogs and humans with OS. In vivo preclinical proof of concept will be determined in mouse xenograft studies and dogs with spontaneous OS for promising drug combinations. Subsequently, we hope to rapidly translate preclinical proof of concept findings to human OS patients.

Citation Format: Joy M. Fulbright, Kathleen Neville, Melinda Broward, Tyce A. Bruns, Anuradha Roy, Peter McDonald, Megan Ottomeyer, Douglas H. Thamm, Tomoo Iwakuma. Comparative oncology drug discovery for Osteosarcoma in dogs and humans. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3689. doi:10.1158/1538-7445.AM2015-3689
Abstract 3697: Development of a focused non-hydrolyzable phosphopeptide library based on a high affinity SHP2 substrate
Authors: Lawrence Harshani R. , Luo Yunting , Gunawan Steven , Becker Andreas , Ren Yuan , Schonbrunn Ernst , Wu Jie , Lawrence Nicholas J.
Published: August 2015

The Src homology-2 domain containing protein tyrosine phosphatase-2 (SHP2), a widely expressed cytoplasmic tyrosine phosphatase with two src-homology 2 (SH2) domains, has received much attention in the signal transduction field. SHP2 is a transducer of growth factor, cytokine, integrin, and hormone signaling pathways that regulate processes such as cell proliferation, differentiation, adhesion, migration, and apoptosis and plays a pivotal role in growth factor and cytokine signaling. Gain-of-function SHP2 mutations are associated with several types of leukemias, and solid tumors; this makes SHP2 is an attractive target for cancer therapy Several small molecules have been developed for inhibition of this important phosphatase, which serve as chemical tools to probe the role of SHP2 in disease and lead compounds for optimization. Nevertheless it is challenging to improve these lead compounds with better potency, selectivity and cell permeability. To gain structural insights for development of potent and selective SHP2 inhibitors, we synthesized a non-hydrolyzable phosphotyrosine peptide mimetic based on reported SHP2 substrate peptide sequence (10-mer). The non-hydrolyzable phosphopeptide, containing the phosphotyrosyl surrogate difluoromethylphosphonate, was synthesized using solid phase peptide synthesis methods from the known building block N-FMOCF2Pmp and we improved the coupling reaction conditions to generate a peptide library of difluoromethylphosphonate to understand the SHP2 affinity. We will present the synthesis of the peptide library, analysis of SHP2 phosphatase inhibition, and the binding mode (X-ray crystal structure) of the phosphopeptide mimic to SHP2.

Citation Format: Harshani R. Lawrence, Yunting Luo, Steven Gunawan, Andreas Becker, Yuan Ren, Ernst Schonbrunn, Jie Wu, Nicholas J. Lawrence. Development of a focused non-hydrolyzable phosphopeptide library based on a high affinity SHP2 substrate. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3697. doi:10.1158/1538-7445.AM2015-3697