bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 5280: A polymorphism of VEGFA is associated with susceptibility to extrathyroidal invasion of papillary thyroid cancer
Authors: Eun Young Gyu , Lee Young Chan , Lee Jung-Woo
Published: August 2015

Background: Vascular endothelial growth factor A (VEGFA) has pivotal roles in angiogenesis, vascular permeability, vasculogenesis, cellular growth, and cell migration. We investigated whether single nucleotide polymorphisms (SNPs) of the VEGFA gene are associated with the development of papillary thyroid cancer (PTC). We also assessed the relationships between VEGFA SNPs and the clinicopathologic characteristics such as the size of cancers (< 1 cm and ≥ 1 cm), numbers of cancers (unifocality and multifocality), location of cancers (one lobe and both lobe), extrathyroidal invasion (present and absent), and cervical lymph node metastasis (present and absent).

Methods: One promoter SNP (rs699947, -2578A/C) and one 5′-untranslation region (5′UTR) SNP (rs2010963, +405C/G) in VEGFA were genotyped using direct sequencing in 94 PTC patients and 213 healthy controls. SNPStats, SNPAnalyzer, Helixtree, and Haploview version 4.2 were used to analyze genetic data. Multiple logistic regression models (codominant, dominant, recessive, and log-additive) were performed to evaluate odds ratios (ORs), 95% confidence intervals (CIs), and p values.

Results: Two SNPs of VEGFA were not associated with the development of PTC. Also, haplotypes were not associated with PTC??. However, we found a relationship between the 5′UTR SNP rs2010963 and PTC with the extrathyroidal invasion (p = 0.0060 in codominant model, p = 0.0258 in dominant model, p = 0.0057 in recessive model, and p = 0.0060 in log-additive model). Allele frequencies of rs2010963 were different between the extrathyroidal invasion (-) and extrathyroidal invasion (+) groups (p = 0.0050). In Bonferroni correction, these correlations were also significant except the recessive model.

Conclusion: Our results suggest that the 5′UTR SNP rs2010963 (+405C/G) of VEGFA may be associated with susceptibility to extrathyroidal invasion of PTC in Korean population.

Note: This abstract was not presented at the meeting.

Citation Format: Young Gyu Eun, Young Chan Lee, Jung-Woo Lee. A polymorphism of VEGFA is associated with susceptibility to extrathyroidal invasion of papillary thyroid 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 5280. doi:10.1158/1538-7445.AM2015-5280
Abstract 5310: Prognostic and predictive biomarkers of clinical response to Bevacizumab in recurrent WHO grade 3 malignant glioma patients
Authors: Toft Anders , Urup Thomas , Grunnet Kirsten , Christensen Ib J. , Michaelsen Signe R. , Broholm Helle , Larsen Vibeke A. , Kosteljanetz Michael , Lassen Ulrik , Poulsen Hans S.
Published: August 2015

Background: Bevacizumab, a monoclonal antibody targeting vascular endothelial growth factor A (VEGF-A), has proven activity in treatment of recurrent high-grade glioma. High response rates have been demonstrated, but particularly in WHO grade 3 malignant gliomas, efforts to identify predictors of clinical response have been limited. Predictive biomarkers and prognostic models are required in order to individualize treatment for this patient population. The primary end-point of this study was identification of prognostic and potentially predictive clinical and paraclinical factors of response. The secondary end-point was to identify prognostic factors associated with progression-free survival (PFS) and overall survival (OS).

Materials and methods: A total of 64 recurrent grade 3 glioma patients treated with bevacizumab and irinotecan were retrospectively evaluated. Eligible patients from our center had a WHO performance status of 0-2 and were administered bevacizumab and irinotecan between December 2005 and November 2014 according to a previously published clinical protocol.

The possibly relevant prognostic baseline factors screened for included: Age, gender, WHO grade 3 diagnosis, tumor size and location, multifocal disease, extent of resection, number of prior chemotherapy regiments, response to prior chemotherapy, first-line treatment, number of previous recurrences, neurological deficit, corticosteroid use, performance status, necrosis, vascular proliferation, neutrophil-to-lymphocyte ratio, and expression of p53, EGFR, Mib-1, MGMT, IDH-1 and ATRX.

Candidate factors were subjected to univariate analysis and factors with P-values below 0.10 were considered for multivariate analysis. Prognostic models were generated by logistic regression and Cox regression, modeling response and survival end-points. P-values below 0.05 were considered statistically significant.

Results will be presented.

Citation Format: Anders Toft, Thomas Urup, Kirsten Grunnet, Ib J. Christensen, Signe R. Michaelsen, Helle Broholm, Vibeke A. Larsen, Michael Kosteljanetz, Ulrik Lassen, Hans S. Poulsen. Prognostic and predictive biomarkers of clinical response to Bevacizumab in recurrent WHO grade 3 malignant glioma patients. [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 5310. doi:10.1158/1538-7445.AM2015-5310
Abstract 5319: Apoptotic properties of platinum antitumor agents phosphaplatins
Authors: Dezvareh Homa
Published: August 2015

Phosphaplatins, a group of non-DNA binding platinum compounds, exhibit excellent in vivo and in vitro efficacies against a variety of cisplatin- and carboplatin-sensitive and resistant ovarian cancers. Although, combinations of cis- or carbo-platin and paclitaxel therapies continue to be the choice of treatment for many ovarian cancer patients, many develop resistance to treatment. Phosphaplatins are pyrophosphate bound platinum-(II) and (IV)-platinum complexes that bi-negatively charged at or near neutral pH. Both Platinum (II) and platinum (IV) complexes did not overexpress any DNA repair genes consistent with the no-DNA binding property of phosphaplatins. In this report, we show the apoptotic properties of two representative compounds, (R,R-1,2-cyclohexanediamine)-(dihydrogen pyrophosphato)platinum (II) (RRD2) and (R,R-1,2-cyclohexanediamine)-trans-dihydroxo(dihydrogen pyrophosphato)platinum (IV) (RRD4) through a variety of experiments as described below.

Phosphaplatins activate and upregulate death receptors on cell surface such as FAS, DR5, and TNFR1. These three death receptors follow the common signaling path to trigger apoptosis by an extrinsic pathway via Death Inducing Signaling Complex (DISC) by recruiting FADD and procaspase-8 and activating caspase-8. A direct binding of FAS by platinum is implicated as the platinum compound was found to be co-localized in the lipid rafts.

The PTEN-PI3K pathway involvement was confirmed by the down regulation of both PI3K and p-AKT. Phosphoplatins also upregulate tumor suppression genes P53 and PTEN. Apoptosis by p53 signaling follows intrinsic pathways involving BCL-proteins. In particular up regulation of BAX, PUMA, and downregulation of BCL2 were observed. To further confirm p53-signailng, we have identified a number of p53 target genes that include AEN, CYFIP2, TP53I3, TP53INP1, DPYSL4, LRDD, DRAM1, and a few others.

Our data shows that phosphaplatins have the potential to not only treat resistant but also advanced metastatic ovarian cancers.

Citation Format: Homa Dezvareh. Apoptotic properties of platinum antitumor agents phosphaplatins. [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 5319. doi:10.1158/1538-7445.AM2015-5319
Abstract 5323: Targeting PIM1 and CDK4/6 kinases in renal cell carcinoma
Authors: Small Jeffery S. , Holder Sheldon L.
Published: August 2015

In this study we examine the hypothesis that combination therapy targeting the VEGFR, PIM1, and CDK4/6 kinases improves the efficacy of VEGFR-directed monotherapy in renal cell carcinoma (RCC).

Two RCC cell lines, 786-O and Caki-1 (chosen for differences in VHL), were evaluated and the ED50s of SGI-1776 (PIM1 inhibitor), PD0332991 (CDK4/6 inhibitor), and LY2835219 (dual PIM1 and CDK4/6 inhibitor) assessed with an MTT assay. Cell Titer-Glo® was used to determine the effects of each of the inhibitors on cellular viability alone and in combination with sunitinib (VEFGR tyrosine kinase inhibitor). The effect of LY2835219 on phosphorylation of BAD, a PIM1 substrate, was assessed by Western blot.

PIM1 and dual PIM1-CDK4/6 inhibition showed more potent effects on cellular viability than CDK4/6 inhibition. ED50 values of each inhibitor for RCC cells are reported in Table 1. Further assays showed greater decreased cellular viability in cells treated with the combination of a PIM1 inhibitor and sunitinib than in cells treated with either a PIM1 inhibitor or sunitinib alone. When combined with sunitinib, dual PIM1-CDK4/6 inhibition was more effective than PIM1 inhibition in 786-O cells. Sunitinib in combination with a CDK4/6 inhibitor was not as effective as in combination with either a PIM1 inhibitor or a dual PIM1-CDK4/6 inhibitor. Western blot analysis showed a decrease in phospho-BAD in cells treated with a dual PIM1-CDK4/6 inhibitor.

Table 1.Potency of Kinase Inhibitors Against RCC Cell LinesInhibitorED50 (786-O; uM)ED50 (Caki-1; uM)SGI-17768.67 (8.13 - 9.25)6.94 (5.05 - 9.53)PD0332991Indeterminate*Indeterminate*LY28352197.46 (6.32 - 8.81)1.18 (1.02 - 1.36)95% confidence intervals are presented in parenthesis. *Highest dose level did not result in a sufficient response to allow for reliable curve fitting to determine the ED50

Our data reveal that targeting PIM1 in combination with sunitinib is superior to sunitinib alone in RCC cell lines. Additionally, in 786-O cells, added CDK4/6 inhibition further improves the efficacy of the combination therapy. Dual PIM1-CDK4/6 kinase targeted therapy in combination with sunitinib is an attractive therapeutic regimen with good potential for translation to the clinic. Ongoing studies include further characterization of the molecular events involved including apoptosis, cell cycle regulation, PIM1 kinase and CDK4/6 kinase activity, and evaluation of the combination therapy in a mouse xenograft model of RCC.

Citation Format: Jeffery S. Small, Sheldon L. Holder. Targeting PIM1 and CDK4/6 kinases in renal cell carcinoma. [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 5323. doi:10.1158/1538-7445.AM2015-5323
Abstract 5327: Simultaneous inhibition of ATR and PARP greatly sensitizes colon cancer cell lines to irinotecan
Authors: Davidson David , Abu-Sanad Atlal , Wang Yunzhe , Hasheminasab Fatemeh , Panasci Justin , Aloyz Raquel , Panasci Lawrence
Published: August 2015

Enhanced DNA damage repair is one mechanism behind colon cancer drug resistance. Thus, targeting molecular components of repair pathways with specific small molecule inhibitors may improve the efficacy of chemotherapy. ABT-888 and VE-821, inhibitors of poly-ADP-ribose-polymerase (PARP) and the serine/threonine-kinase Ataxia telangiectasia related (ATR), respectively, were used to treat colon cancer cell lines in combination with the topoisomerase-I inhibitor irinotecan (SN38). Our findings show that each of these molecules at nontoxic single agent concentrations synergized with SN38 to produce a 2.2 to 3 fold reduction in the 50% inhibitory concentration (IC50) of SN38 (Table 1). When combined, nontoxic concentrations of ABT-888 and VE-821 produced a 4.5 to 27 fold reduction in the IC50 of SN38. Furthermore, the combination of all three agents was associated with maximal G2-M arrest and enhanced DNA-damage (γH2AX). The mechanism of this enhanced synergy was associated with maximal suppression of SN38 induced PARP activity in the presence of both inhibitors. Furthermore, VE-821 enhancement of SN38 induced DNA-PK phosphorylation was abrogated by ABT-888, resulting in more unrepaired DNA damage. This novel combination of DNA repair inhibitors may be useful to enhance the activity of DNA damaging chemotherapies such as irinotecan and help circumvent resistance to this drug in colon cancer.

Cell LineVE-821 (μM)ABT-888 (μM)SN38 (IC50) ± SE (nM)I valueP valueLoVo13.5±1.214.5±1.90.30.020.55.8±2.00.40.030.59.4±1.00.70.0610.53.0±1.20.20.010.50.54.7±1.90.40.02HCT-1168.1±0.713.5±0.50.50.010.55.2±0.60.70.030.53.9±1.10.50.0310.50.3±0.030.10.010.50.52.1±0.40.30.01HT-2920.5±1.819.3±0.60.60.010.512.2±1.30.70.020.512.9±0.70.60.0210.53.9±0.50.30.010.50.56.1±0.20.40.01

Table 1 Colon cancer cell lines LoVo, HCT-116 and HT-29 were treated with SN38 alone or in combination with various concentrations of the ATR inhibitor VE-821 and/or the PARP inhibitor ABT-888. The IC50 values of SN38 were significantly reduced in the presence of VE-821 and/or ABT-888 for all cell lines. Drug synergy (I) values were determined, according to Berenbaum (1978), by calculating the ratio:

(IC50 SN38 with inhibitors/IC50 SN38 alone) + (inhibitor concentration used/IC50 inhibitor alone); I less than 1 = synergism, I equal to 1 = additive effect and I greater than 1 = antogonism.

Citation Format: David Davidson, Atlal Abu-Sanad, Yunzhe Wang, Fatemeh Hasheminasab, Justin Panasci, Raquel Aloyz, Lawrence Panasci. Simultaneous inhibition of ATR and PARP greatly sensitizes colon cancer cell lines to irinotecan. [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 5327. doi:10.1158/1538-7445.AM2015-5327
Abstract 5337: An in silico platform for characterizing ADC bystander effects
Authors: Burton Jackson , Teng Shu-Wen , Zopf Christopher J. , Nolan Ryan , Chakravarty Arijit
Published: August 2015

Introduction

The “bystander effect” is the hypothesized process by which neighboring cancer cells are killed when free drug is released into the tumor environment by dying cells. The extent to which an antibody drug conjugate (ADC) elicits the bystander effect can have significant impact on the magnitude and dynamics of efficacy. Understanding the bystander effect though experimental methods (e.g. video-microscopy) are challenging; however, when supplemented with in silico modeling, mechanistic details can be elucidated. The purpose of this work is to develop a spatial-temporal in silico platform describing tumor cell progression in the presence of an ADC in order to quantify the bystander effect.

Methods

The model employs spatial-stochastic methods to simulate the time evolution of cell death resulting from ADCs and freely diffusing payload based on following parameters: drug to antibody ratio (DAR), linker stability, antigen concentration, ADC cell membrane permeability, ADC-antigen internalization, payload permeability, and payload potency. Specifically, a 2-D rectangular grid of tumor cells, ADCs, and payload are numerically implemented through binary pixel occupation of the grid. Governing rules are then assigned for: mobility for freely diffusing ADCs and payload, reaction rate for ADC binding to antigen-expressing cells, rate of cell death dependent on payload concentration, and internalization rate of payload into non-antigen expressing cells. The simulation is run until stopping criteria are met, e.g. all cells are killed. Baseline parameters can be optimized by fitting the model to in vitro experimental video-microscopy data.

Results

Experimental conditions were simulated with the model to characterize the influence of the aforementioned ADC and biological parameters on the bystander effect.

Conclusions

By incorporating the spatial aspect of ADC mechanics, spatially dependent metrics can be formulated to quantify the bystander effect. The model allows for wide adjustability of the ADC design parameters as well as relevant biological parameters. Thus, by understanding the relative parameter sensitivities, the model can explore design optimization of ADCs that maximize the bystander effect. Through such optimization, the magnitude and dynamics of drug exposure at the site of action can be controlled to maximize efficacy and improve the therapeutic window.

Citation Format: Jackson Burton, Shu-Wen Teng, Christopher J. Zopf, Ryan Nolan, Arijit Chakravarty. An in silico platform for characterizing ADC bystander effects. [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 5337. doi:10.1158/1538-7445.AM2015-5337
Abstract 5362: Andrographolide inhibits prostate cancer by modulating chemokine and cytokines
Authors: Mir Hina , Kapur Neeraj , Singh Rajesh , Sonpavde Guru , Lillard James W. , Singh Shailesh
Published: August 2015

Treatment options for androgen independent prostate cancer (PCa) are limited. Hence, new treatment strategies are needed to treat/prevent hormone refractory advance disease. Major focus of this study was to develop non-toxic therapeutic/preventive option for PCa. Andrographolide (AG), a bioactive diterpenoid isolated from Andrographis paniculata showed dose and time dependent inhibition of PCa cells (PC3, DU145 and LNCaP). This inhibition in growth was due to selective modulation of chemokines and cytokines required for PCa cell growth and proliferation. Specifically, CXCR3 and CXCR7 expression was reduced after AG treatment. Interestingly, AG inhibited IL-6 expression, which is known to be associated with advance PCa and also highly produced by the aggressive PCa cell compared to less aggressive or normal prostatic epithelial cells. Hence, AG may be offered as a new therapeutic/preventive agent against PCa due to its ability to inhibit key chemokines and cytokines required for PCa progression and supporting hormone refractory PCa.

Citation Format: Hina Mir, Neeraj Kapur, Rajesh Singh, Guru Sonpavde, James W. Lillard, Shailesh Singh. Andrographolide inhibits prostate cancer by modulating chemokine and cytokines. [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 5362. doi:10.1158/1538-7445.AM2015-5362
Abstract 5385: Anticancer effects of a novel histone deacetylase inhibitor, SNUCH-1, in glioblastoma
Authors: Choi Seung Ah , Kwak Phi Ae , Lee Young Eun , Phi Ji Hoon , Choi Jung Won , Wang Kyu-Chang , Park Chul-Kee , Kim Seung-Ki
Published: August 2015

Histone deacetylase inhibitors (HDACi) have been evaluated as promising anticancer drugs against glioblastoma cells. However, there are still lack of animal experiments and new HDAC inhibitors for clinical trials. In this study, we demonstrated the therapeutic efficacy of novel pan-HDACi, SNUCH-1, comparing with other traditional pan-HDACi such as trichostatin A (TSA) and vorinostat (SAHA) in vitro and vivo. We performed cell viability, proliferation, cell cycle, apoptosis, HDAC enzyme activity and western blot assay using the three glioblastoma cell lines and two primary cultured cells. Furthermore, we examined the effects of SNUCH-1 by intracisternal administration on the orthotopic human xenograft glioblastoma mice model. We showed that SNUCH-1 decreased cell viability in a dose-dependent manner and suppressed proliferation with a stronger apoptotic activity than TSA and SAHA. SNUCH-1 inhibited HDAC enzyme activity and blocked cell cycle progression at G2/M, regulating cell cycle related protein expression more effectively than TSA and SAHA. In addition, SNUCH-1 significantly reduced tumor volume and revealed more powerful anti-tumor effect in vivo than TSA. Our results suggest that the novel HDAC inhibitor, SNUCH-1, is a potent therapeutic candidate for glioblastoma.

Key words: Histone deacetylase inhibitor, glioblastoma, intracisternal administration

Citation Format: Seung Ah Choi, Phi Ae Kwak, Young Eun Lee, Ji Hoon Phi, Jung Won Choi, Kyu-Chang Wang, Chul-Kee Park, Seung-Ki Kim. Anticancer effects of a novel histone deacetylase inhibitor, SNUCH-1, in glioblastoma. [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 5385. doi:10.1158/1538-7445.AM2015-5385
Abstract 5387: ONC201/TIC10 is effective as a monoagent and synergizes with chemotherapy to induce cell death in non-Hodgkin's lymphoma
Authors: Talekar Mala Kiran , Dicker David , Allen Joshua , El-Deiry Wafik
Published: August 2015

Outcome for non-Hodgkin's lymphoma (NHL) patients using conventional treatment standards remains unsatisfactory, particularly in advanced stage/ relapsed disease creating an imminent need for investigating novel treatment strategies. ONC201/TIC10 is a small molecule (Allen et al, 2013) that induces p53-independent cell death in tumor cells while sparing normal cells through inactivation of the prosurvival kinases Akt and ERK. ONC201 is currently entering Phase I/II clinical trials as a monoagent in adult advanced cancers. We have previously shown that ONC201 induces significant cytotoxicity in preclinical models of human lymphomas (Talekar et al, ASPHO 2014). Here, we show that ONC201 is not only effective as a monoagent across several NHL cell lines, but that it also synergizes with several chemotherapeutic agents to cooperatively induce cell death in vitro.

We found that ONC201 induces significant apoptosis in a diverse panel of human NHL cell lines at low micromolar concentrations (1.3 to 5.06 uM). Increased surface TRAIL and surface DR5 expression was noted in a dose-dependent manner across representative cell lines. The increase in surface TRAIL correlated with increase in sub-G1 DNA content, which suggests that TRAIL may serve as a potential biomarker of response to ONC201. ONC201-induced apoptosis was inhibited using a pan-caspase inhibitor and was blocked by an anti-TRAIL antibody RIK-2, which indicate induction of TRAIL-dependent cell death. Western blot analysis of ONC201-treated NHL cells suggests ERK inhibition and Foxo3a activation as a potential mechanism of cytotoxicity via TRAIL induction. In agreement with this notion, we also observed upregulation of PARP & DR5 and caspase-3 activation in response to ONC201 treatment.

We further found that ONC201 synergizes to potentiate cytotoxicity with several chemotherapeutic agents approved for NHL treatment, particularly anthracyclines (doxorubicin), nitrogen mustard (bendamustine), antimetabolite (cytarabine) and proteasome inhibitor (bortezomib) via cell viability experiments that were corroborated by apoptosis assays. Together these results suggest that ONC201 is a potent antitumor agent in NHL as monoagent and in combination with several approved therapies that may be explored in phase Ib/II trials.

Citation Format: Mala Kiran Talekar, David Dicker, Joshua Allen, Wafik El-Deiry. ONC201/TIC10 is effective as a monoagent and synergizes with chemotherapy to induce cell death in non-Hodgkin's lymphoma. [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 5387. doi:10.1158/1538-7445.AM2015-5387
Abstract 5412: Lysosome disruption rapidly and effectively induces necrosis in aggressive thyroid carcinomas
Authors: Champa Devora , Di Cristofano Antonio
Published: August 2015

Poorly differentiated thyroid cancer (PDTC) and anaplastic thyroid cancer (ATC) are very aggressive and lethal neoplasms for which there is currently no effective therapy. By activating Kras and deleting p53 in the mouse thyroid we have generated a mouse model of PDTC progressing to ATC. These tumors are characterized by elevated levels of anti-apoptotic members of the Bcl2 family. Tumor cell lines established from this model as well as similarly aggressive human thyroid cancer cell lines undergo cell death upon treatment with Obatoclax, an inhibitor of the anti-apoptotic Bcl2 family members. Even though several studies have suggested that Obatoclax induces apoptosis or necroptosis by binding to its designated targets in a number of different cancer models, our studies show that Obatoclax induces necrosis in both human and mouse thyroid cancer cell lines. By exploiting its autofluorescence, we show that Obatoclax is found in association with lysosomes, but not with mitochondria as it would be expected given the location of its known Bcl2-family targets, and that it causes rapid lysosome disruption. Obatoclax was also able to induce a block in the later stages of autophagy, as shown by an accumulation of autophagosomes upon treatment, likely as a result of lysosome impairment. Furthermore, Bafilomycin A1, an inhibitor of lysosomal acidification, counteracts the effect of Obatoclax and allows for cell survival. These findings suggest a novel mechanism of action for Obatoclax, in which direct lysosome disruption leads to necrosis. Strikingly, human and mouse thyroid cancer cell lines are also sensitive to other lysosome-destabilizing agents.

Importantly, transformed human thyroid cell lines are much more sensitive to Obatoclax than non-transformed thyroid cells, suggesting the existence of a useful therapeutic window. Even though Obatoclax has been removed from clinical trials due to low anti-tumor activity and toxic side effects, its efficacy in killing thyroid cancer cells otherwise refractory to treatment, and the alternative mechanism of action involved in this process support a new approach for targeting aggressive thyroid neoplasms. In conclusion, our data show that aggressive thyroid cancer cells are intrinsically sensitive to lysosome destabilization, and this characteristic can be exploited for the development of novel therapeutic approaches.

Citation Format: Devora Champa, Antonio Di Cristofano. Lysosome disruption rapidly and effectively induces necrosis in aggressive thyroid carcinomas. [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 5412. doi:10.1158/1538-7445.AM2015-5412
Abstract 5419: Structure elucidation of G-quadruplex within the mid-region of the kRAS promoter and identification of stabilizing small molecules as promising transcriptional silencers
Authors: Morgan Rhianna K. , Brooks Tracy A. , Rahman Khondaker M.
Published: August 2015

Over 60% of pancreatic cancers harbor mutations in the kRAS oncogene, whose promoter has three distinct guanine-rich regions (near, mid, and far) capable of forming higher order G-quadruplexes (G4s). These important structures have transcriptional silencing potential and stabilizing compounds cause selective apoptosis in kRAS-addicted cells. Previous works in our laboratory have identified the mid-G4 region as having the highest silencing capacity, with little apparent roles for the near- or far-G4 regions. The structure of this mid-region G4 is being elucidated by electromobility shift assay, DNA polymerase stop assay, DMS footprinting, and circular dichroism (CD). In addition, small molecules are being screened by the Förster Resonance Energy Transfer (FRET) melt assay and confirmed by CD for their stabilization potential. We have identified multiple, equilibrating, intramolecular G4s forming within the mid-region of the kRAS promoter. Varying buffer conditions (cations, dehydration, and molecular crowding) affect these formations; the predominating isoform is a tetra-stacked mixed parallel and antiparallel structure with an 8:15:7 loop configuration. Over 1,600 compounds have been screened and several are being pursued as leads. Several compounds selectively stabilized the mid-G4 and suppress kRAS transcription. Our work highlights the mid-G4-forming region of the kRAS promoter a therapeutic target with the utmost promise for pancreatic cancer, and further features the stabilizing potential of targeted compounds. Studies are ongoing to vet the potential of other “hit” compounds from the FRET screen, as well as to elucidate the structure of the kRAS mid-G4 in chromosomal DNA.

Brooks Lab startup funds, DoD, Rhianna Morgan GSC Grant, University of Mississippi School of Pharmacy

Citation Format: Rhianna K. Morgan, Tracy A. Brooks, Khondaker M. Rahman. Structure elucidation of G-quadruplex within the mid-region of the kRAS promoter and identification of stabilizing small molecules as promising transcriptional silencers. [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 5419. doi:10.1158/1538-7445.AM2015-5419
Abstract 5450: Naturally occurring mutations in the MPS1 gene predispose cells to kinase inhibitor drug-resistance
Authors: Gurden Mark D. , Westwood Isaac , Faisal Amir , Naud Sébastien , Cheung Jack , McAndrew Craig , Wood Amy , Schmitt Jessica , Boxall Kathy , Mak Grace , Workman Paul , Burke Rosemary , Hoelder Swen , Blagg Julian , Van Montfort Rob , Linardopoulos Spiros
Published: August 2015

Acquired resistance is the greatest challenge to the effectiveness of targeted anti-cancer therapies in the clinic. With several MPS1 inhibitors under pre-clinical development, we aimed to investigate how cancer cells will develop resistance against these inhibitors; therefore we modeled acquired resistance using a range of MPS1 inhibitors. We identified and characterized five point mutations in the kinase domain of MPS1 that confer resistance against multiple inhibitors. Structural studies showed that several MPS1 mutants conferred resistance by causing steric hindrance to inhibitor binding. One mutation in particular, p.C604W, which is close to the gatekeeper residue, rendered MPS1 resistant to all the inhibitors we tested. However, we were able to design new compounds to specifically overcome this mutation, which in fact targeted the mutant with more potency than the wild-type MPS1 protein. Importantly, we show that these mutations are present in untreated cancer cell lines and primary tumour samples, and also pre-exist in normal lymphoblast and breast tissues. Furthermore, to confirm this is not specific to MPS1, we show that the EGFR p.T790M mutation is also pre-existing in cancer cell lines and normal tissue. Our data therefore suggest that mutations conferring resistance to targeted therapy are naturally occurring mutations in normal and cancer cells that are not introduced due to cancer cells being more mutagenic.

Citation Format: Mark D. Gurden, Isaac Westwood, Amir Faisal, Sébastien Naud, Jack Cheung, Craig McAndrew, Amy Wood, Jessica Schmitt, Kathy Boxall, Grace Mak, Paul Workman, Rosemary Burke, Swen Hoelder, Julian Blagg, Rob Van Montfort, Spiros Linardopoulos. Naturally occurring mutations in the MPS1 gene predispose cells to kinase inhibitor drug-resistance. [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 5450. doi:10.1158/1538-7445.AM2015-5450
Abstract 5452: Inhibition of sodium-independent and sodium-dependent nucleobase transport activities by tyrosine kinase inhibitors
Authors: Damaraju Vijaya L. , Kuzma Michelle , Cass Carol E. , Sawyer Michael B.
Published: August 2015

Inhibition of nucleobase transport activities by tyrosine kinase inhibitors (TKIs) has not been studied to date. Since many targeted TKIs are often combined with either capecitabine or 5-fluorouracil (5-FU) in treatment of various advanced cancers, we examined TKI effects on both equilibrative nucleobase transport (ENBT) and sodium-dependent nucleobase transport (SNBT) activities. Our goal was to study effects of TKIs on human ENBT and SNBT activities to explore potential TKI interactions with nucleobase chemotherapy drugs. Effects of TKIs on ENBT activities were investigated in normal human renal proximal tubule epithelial cells (hRPTECs). TKI effects on SNBT activities were assessed in a pig kidney cell line (LLC-PK1). We showed that TKIs inhibited both ENBT and SNBT activities to different extents. Gefitinib inhibited ENBT activity with an IC50 value of 0.7 μM thus indicating high sensitivity of ENBT to inhibition by gefitinib in hRPTECs. Erlotinib > sorafenib > imatinib > sunitinib inhibited ENBT with IC50 values of 15, 40, 60, 78 μM, respectively whereas dasatinib, lapatinib and vandetanib were not inhibitory at concentrations >100 μM. Similar studies in LLC-PK1 cells, which exhibit SNBT activity, showed that vandetanib was the most potent inhibitor followed by sorafenib > erlotinib > gefitinib > sunitinib > imatinib with IC50 values of 14, 25, 28, 40, 47 and 94 μM, respectively whereas dasatinib and lapatinib were not inhibitory at concentrations >100 μM. These results indicate inhibition of both ENBT and SNBT activities by exposure of cells to TKIs. These effects on nucleobase transport activities, which could be direct or indirect, suggest why regimens combining gefitinib and 5-FU have failed. Further studies should test all TKI classes for such inhibitory activities to assess potential effects on combination regimens using TKIs with nucleobase drugs such as 5-FU in cancer treatment.

Citation Format: Vijaya L. Damaraju, Michelle Kuzma, Carol E. Cass, Michael B. Sawyer. Inhibition of sodium-independent and sodium-dependent nucleobase transport activities by tyrosine kinase 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 5452. doi:10.1158/1538-7445.AM2015-5452
Abstract 5454: Wogonin overcomes cisplatin resistance of head and neck cancer by targeting antioxidant defense mechanisms
Authors: Kim Ji Won , Kim Eun Hye , Park Jin Young , Kwon Minsu , Roh Jong-Lyel
Published: August 2015

Background: Cisplatin is a first-line chemotherapeutic agent for head and neck cancer (HNC). However, the main limitation to clinical usefulness of cisplatin is the high incidence of chemoresistance causing one of major failures in cancer management. This may suggests the necessity of combination therapies of cisplatin with other drugs to circumvent chemoresistance. Wogonin, one of major natural flavonoids, is known to reverse multidrug resistance in several types of cancers, however, which has been rarely tested in HNC cells. Therefore, the present study investigated the ability and molecular mechanisms of wogonin overcoming cisplatin resistance in HNC cells.

Methods: Two cisplatin-resistance HNC cell lines (AMC-HN4R and -HN9R) and their parental and other human HNC cell lines were used. The effect of wogonin, alone and in combination with cisplatin, was assessed in HNC cells and normal cells by measuring cell viability, cell cycle and death assays, reactive oxygen species (ROS) production, and protein expression, and in preclinical tumor xenograft mouse models.

Results: Wogonin selectively killed HNC cells but spared normal cells. It inhibited NF-E2-related factor 2 (NRF2), P-glycoprotein, and glutathione S-transferase P (GSTP), overexpressed in cisplatin-resistant HNC cells, resulting in the increased ROS accumulation in HNC cells, an effect that can be blocked by the antioxidant N-acetyl-L-cysteine. Wogonin also induced selective cell death by targeting the antioxidant defense mechanisms enhanced in the resistant HNC cells and subsequently, effectively activating cell death pathways involving PUMA and PARP. Therefore, wogonin significantly sensitized the resistant HNC cells to cisplatin in vitro and in vivo.

Conclusions: Wogonin might be the promising anticancer candidate by inducing ROS accumulation and selective killing HNC cells, thus contributing to overcome the cisplatin-resistance of HNC cells.

Citation Format: Ji Won Kim, Eun Hye Kim, Jin Young Park, Minsu Kwon, Jong-Lyel Roh. Wogonin overcomes cisplatin resistance of head and neck cancer by targeting antioxidant defense mechanisms. [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 5454. doi:10.1158/1538-7445.AM2015-5454
Abstract 5488: Utilizing a pathway based analysis of genome wide association data to identify biomarkers of toxicity in breast cancer patients
Authors: Bidadi Behzad , Kalari Krishna R. , Rubner Matthias , Hein Alexander , Beckmann Matthias W. , Fasching Peter A. , Rack Brigitte , Janni Wolfgang , Weinshilboum Richard , Wang Liewei
Published: August 2015

Breast cancer is the most common invasive cancer in women worldwide and treatment related toxicity has high inter-patient variability. Our goal was to identify additional genetic predictors of toxicity by completing a pathway based analysis taking advantage of the genotyping results obtained through a GWAS of the same patients. For our analysis, we have utilized GWA data from the SUCCESS-A trial in which 3,754 breast cancer patients were treated with adjuvant chemotherapy. We have included SNPs associated with 112 genes involved in drug disposition and 375 genes in selected cancer pathways.

We identified 35 SNPs associated with neutropenia (P-value <1×10−4). These patients initially received three cycles consisting of 5-fluorouracil (5-FU), cyclophosphamide, and epirubicin. Currently we are characterizing the function of three SNPs located within an intron of the hyaluronan mediated motility receptor (HMMR) gene that are associated with the neutropenia phenotype (P-value <1×10−4). These SNPs are highly associated with the expression of a gene encoding a B-cell survival factor, TNFSF13B, (P-value <1×10−5).

Our in vitro studies using lymphoblastoid cell lines (LCLs) selected based on the genotypes of HMMR gene showed that heterozygous and homozygous variant cells (n = 6) have an increased sensitivity to 5-fluorouracil, but not cyclophosphamide or epirubicin when compared with homozygous wild-type cells (n = 6). LCLs exposed to the previously mentioned chemotherapeutic agents resulted in an upregulation of TNFSF13B gene expression and downregulation of HMMR gene expression.

We have utilized a pathway based approach to analyzing GWA data to identify several SNPs in the HMMR gene highly associated with the expression of one of the top signals in the cytopenia GWAS. Our goal is to further characterize the role of HMMR gene variants in chemotherapy response by assessing whether combinations of these agents in vitro (including 5-FU) also have a genotype dependent response to cytotoxicity.

Citation Format: Behzad Bidadi, Krishna R. Kalari, Matthias Rubner, Alexander Hein, Matthias W. Beckmann, Peter A. Fasching, Brigitte Rack, Wolfgang Janni, Richard Weinshilboum, Liewei Wang. Utilizing a pathway based analysis of genome wide association data to identify biomarkers of toxicity in breast cancer patients. [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 5488. doi:10.1158/1538-7445.AM2015-5488
Abstract 5512: Preclinical evaluation of the recombinant human arginase PEG-BCT-100 leading to arginine deprivation in sarcomas
Authors: Choy Chi Tung , Cheong Hio Teng , U Kin Pong , Wong Chi Hang , Loong Herbert Ho Fung
Published: August 2015

Background: Arginine deprivation is a novel approach to limit arginine-dependent tumour growth. The presence of enzymes involved in the de novo synthesis of arginine from citrulline, argininosuccinate synthetase (ASS), argininosuccinate lyase (ASL) and ornithine transcarbamylase (OTC), can influence the sensitivity of tumour to arginine depletion. We studied the preclinical efficacy of PEG-BCT-100 (also known as rhArg1peg5000), a PEGylated recombinant human arginase 1 on sarcoma cell lines. In this study, ASS, ASL and OTC expression were established in sarcoma cell lines and the sensitivity of each cell line to PEG-BCT-100 treatment was determined in order to establish their suitability as predictive markers to determine responsiveness to PEG-BCT-100 treatment.

Methods: Cells from 5 representative soft-tissue sarcoma (STS) cell lines (RD, GCT, HT-1080, SW872, SW982) and 1 osteosarcoma cell line (SJSA-1), either incubated in full culture medium (control), arginine free medium or PEG-BCT-100 (1U/ml) treated medium. They were monitored by live cell imaging for 72 hours. Their corresponding IC50 were determined by cell viability assay. The expression of ASS, ASL and OTC were determined by Western blotting.

Results: All sarcoma cell lines were sensitive to PEG-BCT-100 and demonstrated significant cell proliferation inhibition. Their IC50, as determined by cell viability assay were 0.023 U/ml, 0.028 U/ml, 0.023 U/ml, 0.026 U/ml, 0.20 U/ml, 0.053 U/ml, and 0.03 U/ml for GCT, HT-1080, RD, SJSA-1, SW872 and SW982 respectively. Western blot analysis confirmed strong basal protein expression of ASL and low OTC expression in all sarcoma cell lines, suggesting sensitivity to PEG-BCT-100 is not determined by ASL but rather, OTC. On the contrary, low ASS basal protein expression was revealed in all sarcoma cell lines except for RD. A strongly expressed ASS was observed in RD despite of its sensitivity to PEG-BCT-100, implying that ASS might be less important in the response towards PEG-BCT-100.

Conclusion: Arginine deprivation by PEG-BCT-100 is effective in suppressing STS cell growth in vitro, suggesting arginine auxotrophism in STSs. Moreover, arginase treatment can be an effective strategy against STS. Low expression of OTC, instead of ASS and ASL, may be a more important predictive biomarker for response to treatment. Further in-vivo and clinical studies are warranted.

Citation Format: Chi Tung Choy, Hio Teng Cheong, Kin Pong U, Chi Hang Wong, Herbert Ho Fung Loong. Preclinical evaluation of the recombinant human arginase PEG-BCT-100 leading to arginine deprivation in sarcomas. [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 5512. doi:10.1158/1538-7445.AM2015-5512
Abstract 5531: Combination drug delivery using PBM nanoparticle to improve prostate cancer therapy
Authors: Singh Rajesh , Singh Shailesh , Sonpavde Guru P. , Lillard James W.
Published: August 2015

Docetaxel is the standard first-line chemotherapy for advanced prostate cancer (PCa). The key challenges in this treatment option are dose-limiting toxicities, acquired resistance, and lack of tumor cell specificity. Adjuvants and docetaxel encapsulation have been proposed to mitigate many of these hindrances. The proposed study evaluated a novel method for targeted delivery of resveratrol alone or in combination with docetaxel at desired rates. We described a proprietary planetary ball milling approach (PBM) that uses a natural polysaccharide (starch; FDA approved) to create a drug-polysaccharide nanoparticle as a core that is subsequently coated with novel folate-conjugated poly (ϵ-caprolactone) / poly (ethylene glycol) co-polymer, which allows binding to high affinity folate receptors present on PCa cells. The resulting PBM nanoparticles were shown to be rapidly internalized and induce significant cancer cell apoptosis at lower doses, than compared to unformulated resveratrol and/or docetaxel. Importantly, negative controls showed that PBM nanoparticles without resveratrol or docetaxel had no toxic effects on PCa cells. Furthermore, our data also suggests that resveratrol potently synergizes with docetaxel to inhibit proliferation and induce 60% cell death in PCa cell lines at concentrations lower than the IC50. Since docetaxel is associated with various debilitating toxicities, a synergistic combination of resveratrol-docetaxel with targeted delivery to tumor cells could provide a more potent therapeutic effect at lower drug concentrations and improve therapeutic index.

Citation Format: Rajesh Singh, Shailesh Singh, Guru P. Sonpavde, James W. Lillard. Combination drug delivery using PBM nanoparticle to improve prostate cancer therapy. [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 5531. doi:10.1158/1538-7445.AM2015-5531
Abstract 5543: Elucidating the cytotoxic effects of taxol,camptothecin and Lobostemon fruticosus extracts on non-small cell lung cancer
Authors: Motadi Lesetja Raymond , Ndlovu Lungile
Published: August 2015

Lung cancer is reportedly the most common form of cancer worldwide, with a 13-15% occurrence of all known cancers being reported daily. Lung cancer is also the most deadly form of cancer as it has been observed to be resistant to most therapeutic treatments and it demonstrates a metastasis within lymph nodes. An alternative approach is to identify the cytotoxic effects of non-invasive medicinal plant extracts on NSCLC. Thus the aim of the study was to compare the cytotoxic effects of the invasive anti-cancer drugs, taxol and camptothecin, with less invasive plant extracts of L. fruticosus on cell line A549. Cells seem to show a degree of cell death after treatment however some degree of cells still remain viable indicating usefulness in chemotherapy. The following techniques were used, exCELLigence RTCA, Cell cycle, Annexin V apoptosis analysis and LC-MS to identify the compound. Cells treated with camptothecin, Methanol and butanol extracts indicate some degree of early apoptosis which was indicative of little to no DNA fragmentation. Cell cycle arrest was observed in both camptothecin and taxol treated cells, however there was little evidence to suggest the same for L. Fruticosus extracts as there was a high degree of cell death that was observed during the cell cycle analysis. Apoptotic genes that were found in A549 treated cells upregulated in the absence of p53. Phytochemical screening of the L. Fruticosus plant extracts indicated that the plant possesses compounds that display apoptotic activity. These findings suggest that camptothecin, taxol and extract of L. fruticosus display cytotoxic activity on A549 cells. The upregulation of genes in absence of p53 seem to suggest that treatments induce apoptosis using an alternative apoptotic pathway.

Note: This abstract was not presented at the meeting.

Citation Format: Lesetja Raymond Motadi, Lungile Ndlovu. Elucidating the cytotoxic effects of taxol,camptothecin and Lobostemon fruticosus extracts on non-small cell 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 5543. doi:10.1158/1538-7445.AM2015-5543