bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 434: Radiation-induced matrix metalloprotease-9 promotes mesenchymal transition of Daoy cells and initiates activation of pro-matrix metalloprotease-2.
Authors: Nalla Arun Kumar , Asuthkar Swapna , Dasari Venkata Ramesh , Rao Jasti S.
Published: August 2014

Ionizing radiation is an efficient therapeutic modality against cancer and a potent carcinogenic agent with the ability to alter cellular genotype. Earlier, we reported that medulloblastoma cells exposed to ionizing radiation showed enhanced invasive and adhesive characteristics. Invasion is the cumulative effort of cells to degrade the extracellular matrix (ECM) and to modulate cellular phenotype to invade the ECM. Therefore, we examined the modulation gained by irradiated medulloblastoma cells leading to enhanced invasiveness. Radiation-induced invasion increased with the increase in the recovery time after radiation treatment and was identified to be associated with MMP-9/MMP-2 activity. Radiation enhanced the expression of MMP-9 and induced the cleavage of pro-MMP-2 into active form, and the latter was associated with MT-MMP-1 expression. A significant time lag observed between the radiation exposure time and MMP-2 activation was identified as a period required for the irradiated cells to acquire cellular alteration, such as mesenchymal characteristics. Recombinant protein(s) and inhibitor(s) studies demonstrated that radiation-induced MT-MMP-1 expression and MMP-2 activation are in harmony with JNK activation. MMP-9 gene silencing and protein supplementation studies confirmed that MMP-9 activates JNK signaling and potent inducers of mesenchymal markers such as Snai1 and N-Cadherin. Further, gene-specific silencing of either MMP-9 or N-Cadherin showed significant reduction of MMP-2 activation in irradiated Daoy cells. Collectively, our results provide an insight on the role of MMP-9 in radiation-induced invasion and in initiating signaling cascades that modulate Daoy cells to acquire mesenchymal characteristics and activate MMP-2.

Citation Format: Arun Kumar Nalla, Swapna Asuthkar, Venkata Ramesh Dasari, Jasti S. Rao. Radiation-induced matrix metalloprotease-9 promotes mesenchymal transition of Daoy cells and initiates activation of pro-matrix metalloprotease-2. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 434. doi:10.1158/1538-7445.AM2013-434
Abstract 4346: Formulation and characterization of a nanoparticulate drug delivery system for cancer therapy.
Authors: Desai Kunal P. , Patel Jay V. , Do Duc P.
Published: August 2014

Most anticancer agents are not targeted to neoplastic cells. As a result, the development of dosage forms and drug delivery systems containing anticancer drugs capable of targeting cancer cells is highly desired. Our research investigated an albumin-based nanoparticulate delivery system as a platform technology for the delivery of anticancer agents. Doxorubicin hydrochloride was used as the model drug. Drug-encapsulated nanoparticles were prepared by microencapsulation through spray-drying and were characterized for their physicochemical properties. Raman spectroscopy was used to investigate the stability of the encapsulated drug. Additionally, Zeta potential measurements were used to assess the colloidal stability and surface properties of the nanoparticles. Dissolution studies were carried out to examine the release profile of the drug from the nanoparticles. The in vitro efficacy of the drug-loaded nanoparticulate drug delivery system was analyzed in MCF-7 breast cancer cell line. Raman spectroscopy data suggested that the drug is stable in the nanoparticulate drug carrier. Nanoparticles have Zeta potential measurements of approximately -30 mV, suggesting that the system is stable in an aqueous environment. Dissolution studies showed that the drug was released from the nanoparticles at a sustained rate over a period of over 24 hours. In vitro data in MCF-7 cell line indicated that there was more than 10% more inhibition of cell viability when doxorubicin was used with the biodegradable polymeric carrier. Similar results were observed from clonogenic studies. Additionally, our in vitro data suggested that cell death induced by the drug-loaded nanoparticles was caused by apoptosis. Hence, the data suggest that biodegradable albumin nanoparticles are capable of targeting cancer cells.

Citation Format: Kunal P. Desai, Jay V. Patel, Duc P. Do. Formulation and characterization of a nanoparticulate drug delivery system for cancer therapy. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 4346. doi:10.1158/1538-7445.AM2013-4346
Abstract 437: ATM regulates glioma migration via MEK-ERK not AKT.
Authors: Allen Jasmine L. , Wagner Allison F. , Beckta Jason M. , Watson James , Golding Sarah E. , Valerie Kristoffer C.
Published: August 2014

Glioblastoma multiforme (GBM) is a lethal brain cancer with a life expectancy of only 12-15 months. Current standard treatment for GBM is surgery and chemoradiation. However, there are many difficulties when it comes to treating this aggressive brain cancer due to the inherent radio- and chemo-resistance. Consequently, there is a critical need for new therapeutic approaches to make radiation/chemotherapy more effective. Ataxia telangiectasia (A-T) patients are extremely sensitive to ionizing radiation. The protein mutated in A-T, ATM (A-T mutated), controls the cells’ response to radiation, referred to as the DNA damage response (DDR). ATM is a master protein kinase that targets many proteins during the DDR including regulators of cell cycle checkpoints, DNA repair, and apoptosis. In addition, without any radiation, ATM might regulate glioma dispersal. Using a highly specific inhibitor of the ATM kinase (ATMi), we recently showed that ATM regulates both the ERK and AKT signaling pathways and controls glioma cell migration and invasion in vitro. To take these studies further we have now used a genetic approach and knocked down ATM in human glioma cells. We have recapitulated our previous finding with an ATMi and shown that ATM knockdown glioma cells have reduced ability to migrate in vitro. In order to determine whether MEK/ERK and/or AKT regulate migration, human glioma cells were exposed to a MEK (PD0325901) or an AKT (MK-2266) inhibitor in a ‘scratch-assay’. We found that only the former compound affected migration in vitro. Hence, we have shown that ATM regulates glioma migration in vitro, perhaps via MEK/ERK. On the other hand, ATM might regulate invasion via AKT. The signaling relationship in vitro between ATM, ERK, and AKT is currently being investigated. Furthermore, ongoing studies will establish whether ERK and AKT signaling affect migration and invasion in vivo.

Citation Format: Jasmine L. Allen, Allison F. Wagner, Jason M. Beckta, James Watson, Sarah E. Golding, Kristoffer C. Valerie. ATM regulates glioma migration via MEK-ERK not AKT. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 437. doi:10.1158/1538-7445.AM2013-437

Note: This abstract was not presented at the AACR Annual Meeting 2013 because the presenter was unable to attend.
Abstract 4370: Protein kinase inhibitor screening uncovers differential kinase dependencies in triple negative breast cancer (TNBC).
Authors: Fink Lauren S. , Beatty Alexander , Devarajan Karthik , Peri Suraj , Peterson Jeffrey R.
Published: August 2014

Triple-negative breast cancer (TNBC) constitutes approximately 20% of all breast cancer and disproportionately affects younger women and African-American women. These tumors, negative for estrogen receptor, progesterone receptor, and Her2 amplification, are resistant to standard targeted treatments, and the need for new therapeutic targets for this tumor type is urgent. Within the TNBC patient population, there is variability in response to treatment, and it is unclear what molecular features of the disease lead to this heterogeneity. Protein kinases are often amplified and/or mutated in human cancers, and they are attractive therapeutic targets due to their enzymatic activity and widespread expression. We have screened a library of small-molecule kinase inhibitors against a panel of 12 TNBC cell lines and 3 control cell lines in duplicate in cell viability assays. We generated dose-response curves and half maximal inhibitory concentration (IC50) values for each compound-cell line pair. The results support a heterogeneous dependence of different TNBC cell lines on specific kinases. Statistical analysis identifies significantly over-represented kinase targets and pathways in subsets of TNBC cell lines following inhibitor treatment. A number of compounds show selective toxicity for TNBC cell lines and suggest targetable kinase dependencies. Kinase inhibitor sensitivity in TNBC does not appear to correlate with gene expression patterns, suggesting alternative mechanisms for TNBC heterogeneity. Sequencing data and other biomarkers databases will be mined for correlations with sensitivity to kinase inhibition in TNBC. Thus this study will identify new potential therapeutic targets and biomarkers for TNBC.

Citation Format: Lauren S. Fink, Alexander Beatty, Karthik Devarajan, Suraj Peri, Jeffrey R. Peterson. Protein kinase inhibitor screening uncovers differential kinase dependencies in triple negative breast cancer (TNBC). [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 4370. doi:10.1158/1538-7445.AM2013-4370
Abstract 4377: The Golgi protein GLG1 coordinates ARF3 activation in tumor cells.
Authors: Planche Anne
Published: August 2014

Increasing evidence suggests that endocytosis and membrane trafficking are deregulated in cancer cells. Because of their dependence on selected signaling pathways, tumor cells may need to rely on accelerated receptor recycling and increased secretion of a variety of molecules such as matrix components, adhesion molecules and growth factors. Mass spectrometry analysis of proteins associated with separase, recently shown to be an important regulator of membrane trafficking, identified the Golgi apparatus protein 1 (GLG1). GLG1 is primarily known as an E-selectin ligand that mediates the initial step of tethering and rolling of leukocytes on vascular endothelium. We therefore addressed the possibility that GLG1 could play a similar role in circulating tumor cells, facilitating arrest and extravasation into adjacent tissues. Consistent with this possibility, tail vein injection of stably GLG1-depleted tumor cells into NOD/SCID mice resulted in reduced numbers of metastatic nodules. Moreover, metastatic tumor growth was almost exclusively intravascular, indicating impaired extravasation of tumor cells. Further investigation, however, showed that, in tumor cells, GLG1 is almost exclusively localized to the Golgi apparatus, challenging the notion that it plays a direct role in mediating tumor cell adhesion to endothelium as in leukocytes.

To elucidate the molecular mechanisms by which GLG1 could affect tumor cell migration through interactions at the Golgi level, we conducted various experiments using GLG1-depleted human tumor cell lines. Transient silencing of GLG1 by siRNA was observed to modify cell shape (elongated morphology), to reduce migration of a range of tumor cell lines and to markedly alter Golgi architecture. Interestingly, subsequent experiments led to the identification of a new interactor of GLG1, the Brefeldin A-inhibited guanine nucleotide-exchange protein 1 (BIG1), an ARF-GEF required to initiate membrane vesicle formation at the trans-Golgi compartment by promoting guanine-nucleotide exchange on ARF1 and ARF3. GLG1 was shown to participate in BIG1 and ARF3 recruitment to the Golgi membrane and subsequent ARF3 activation. Surprisingly, the observed morphological disruption of the Golgi apparatus and reduced ARF3 activation did not affect the secretory pathway in general, but rather seemed to impair secretion of selected molecules including MMP-9.

Taken together, our observations provide insight into a novel and specific role of GLG1 in tumor progression by affecting, thanks to its privileged position in the secretory pathway, trafficking of key molecules implicated in cell migration.

Citation Format: Anne Planche. The Golgi protein GLG1 coordinates ARF3 activation in tumor cells. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 4377. doi:10.1158/1538-7445.AM2013-4377
Abstract 4394: Salinomycin downregulates PDGFRβ and c-Myc in human medulloblastoma.
Authors: Wu Erxi
Published: August 2014

Medulloblastoma (MB) is the most common childhood brain tumor and approximately one-third of patients with MB tumors remain incurable. In a goal of search for more effective therapeutic agents to treat MB, we tested the effects of salinomycin, an anti-coccidial drug showing inhibitory effects on breast cancer stem cells with more than 100-fold potency than paclitaxel, in MB cells in vitro. In this study, we first determined the cytotoxicities of salinomycin in MB cells in vitro using cell based assays and demonstrated that salinomycin inhibits cell proliferation, induces cell death and cell cycle arrest in MB cells. We then analyzed the effects of salinomycin on the expression of some key mediators involved in cell death and cell cycle progression and demonstrated that salinomycin up-regulates the expression of cyclin A and down-regulates the expression of Bcl-2 and p21 in MB cells. Finally, we examined the effects of salinomycin on the expression of PDGFRβ and c-Myc, two potential critical therapeutic targets in MB, and found that it suppresses the expression of c-Myc and PDGFRβ in MB cells. Our data suggest that salinomycin may be used as a novel therapeutic agent to treat patients with MB.

Citation Format: Erxi Wu. Salinomycin downregulates PDGFRβ and c-Myc in human medulloblastoma. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 4394. doi:10.1158/1538-7445.AM2013-4394
Abstract 4433: DW-MR imaging as a predictive biomarker of radiosensitization of GBM through targeted inhibition of checkpoint kinases.
Authors: Williams Terence , Galbán Stefanie , Li Fei , Heist Kevin , Galbán Craig , Lawrence Theodore S. , Holland Eric C. , Thomae Tami , Chenevert Thomas , Rehemtulla Alnawaz , Ross Brian D.
Published: August 2014

Purpose: The inherent treatment resistance of glioblastoma (GBM) can involve multiple mechanisms including checkpoint kinase (Chk1/2) mediated increased DNA repair capability which can attenuate the effects of genotoxic chemotherapies and radiation. The goal of this study was to evaluate DW-MRI as a biomarker for Chk1/2 inhibitors in combination with radiation for enhancement of treatment efficacy in GBM.

Experimental Design: We evaluated a specific small molecule inhibitor of Chk1/2, AZD7762, in combination with radiation using in vitro human cell lines and in vivo using a genetically engineered GBM mouse model. Diffusion-weighted and T1-contrast MRI were used to follow treatment effects on intracranial tumor cellularity and growth rates, respectively.

Results: AZD7762 inhibited clonal proliferation in a panel of GBM cell lines and increased radiosensitivity in p53-mutated GBM cell lines to a greater extent compared to p53-wild type cells. In vivo efficacy of AZD7762 demonstrated a dose-dependent inhibitory effect on GBM tumor growth rate and a reduction in tumor cellularity based on DW-MRI scans along with enhancement of radiation efficacy.

Conclusion: DW-MRI was found to be a useful imaging biomarker for the detection of radiosensitization through inhibition of checkpoint kinases. Chk1/2 inhibition resulted in antiproliferative activity, prevention of DNA-damage induced repair, and radiosensitization in preclinical GBM tumor models, both in vitro and in vivo. The effects were found to be maximal in p53-mutated GBM cells. These results provide the rationale for integration of DW-MRI in clinical translation of Chk1/2 inhibition with radiation for the treatment of GBM.

Citation Format: Terence Williams, Stefanie Galbán, Fei Li, Kevin Heist, Craig Galbán, Theodore S. Lawrence, Eric C. Holland, Tami Thomae, Thomas Chenevert, Alnawaz Rehemtulla, Brian D. Ross. DW-MR imaging as a predictive biomarker of radiosensitization of GBM through targeted inhibition of checkpoint kinases. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 4433. doi:10.1158/1538-7445.AM2013-4433
Abstract 4442: Enhancement of radiation response in KRAS mutant non-small cell lung cancer cells with the MEK inhibitor GSK1120212.
Authors: Lin Steven H. , Zhang Jing , Giri Uma , Heymach John V.
Published: August 2014

Biomarkers that can select appropriate patient subsets for optimal treatment will likely improve personalized delivery of cancer treatment. While radiotherapy is a cornerstone for the management of non-metastatic lung cancers, there are no clinically useful biomarkers to help predict for radiation responsiveness and to help select drugs to enhance radiation sensitization in non-small cell lung cancer (NSCLC). KRAS mutations are found in 20%-30% of NSCLC and confer drug resistance. Drugs that target downstream pathways activated in KRAS mutant cells could enhance cytotoxic effects. The purpose of this study is to evaluate if the potent MEK1/2 inhibitor GSK1120212 can selectively enhance radiation response based on the genomic context in lung cancer cell lines. We selected a panel of NSCLC cell lines with or without KRAS mutations and tested their response to combinational treatment with radiation and MEK inhibitor via clonogenic survival assay. We found that GSK1120212 had no radiation enhancement effect in the three KRAS wild type (WT) cell lines tested. In contrast, in three KRAS mutant lung cancer cells, GSK1120212 dramatically reduced clonogenic survival to radiation treatment (radiation enhancement factor 1.2-1.9). We found that GSK1120212 selectively induced G1 cell cycle arrest through regulating the expression of several cell cycle regulation proteins, such as Cyclin B1, Cyclin E1 and RB. GSK1120212 also enhanced the G2/M phase arrest caused by radiation therapy and significantly decreased cell number in S phase. Ultimately, this led to cellular senescence selectively in KRAS mutant but not WT cells. At the dose chosen for this study (IC30), GSK1120212 didn't augment DNA damage or induce cell apoptosis caused by radiation. Taken together, our data suggested that MEK inhibitor GSK1120212 may have some selectivity in enhancing radiation effects in KRAS mutant lung cancer cells. A phase I clinical trial is currently ongoing to test the safety and preliminary efficacy of combining GSK1120212 and chemoradiation in locally advanced NSCLC.

Citation Format: Steven H. Lin, Jing Zhang, Uma Giri, John V. Heymach. Enhancement of radiation response in KRAS mutant non-small cell lung cancer cells with the MEK inhibitor GSK1120212. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 4442. doi:10.1158/1538-7445.AM2013-4442
Abstract 4453: Development and characterisation of AZD-8931-resistant HER-2 positive breast cancer cells.
Authors: Creedon Helen , Muir Morwenna , Hayward Larry , Brunton Valerie
Published: August 2014

The introduction of HER-2 directed therapies has revolutionised the management of both early and advanced HER-2 positive breast cancer. However, despite significant improvements in treatment outcomes, both inherent and acquired resistance are frequently encountered problems. Emerging evidence from early phase neo-adjuvant clinical trials, such as Neo-sphere and Neo-ALTTO, suggests that targeting multiple members of the Human epidermal growth factor receptor (HER) family is more efficacious than single target inhibition. AZD 8931 is a novel equipotent reversible tyrosine kinase inhibitor of EGFR, HER-2 and HER-3 signalling with proven pre-clinical efficacy in breast, head and neck and non-small cell lung cancers {1}.

To investigate potential mechanisms of acquired resistance to AZD-8931, HER-2 amplified SKBR-3 breast cancer cells were rendered resistant by culture with escalating doses of drug. Resistant and parental cell lines were phenotypically distinct with resistance being associated with greater cell spreading and increased cell density. Cross resistance to lapatinib, a reversible dual EGFR/HER 2 tyrosine kinase inhibitor, was demonstrated with an over 50 fold increase in IC50. Signalling changes associated with a resistant phenotype were explored with a combination of Reverse Phase Protein Array (RPPA) and western blotting. Following drug treatment, resistant cells still displayed a dose-dependent reduction in phospho HER-2 (Tyr 1248)/EGFR (Tyr 1173). However, constitutive activation of the HER 3 pathway resulted in persistent downstream signalling via the PI3K/AKT pathway and increased cell survival.

Tumorigenesis in the MMTV-Nic model is driven by mammary-specific expression of a constitutively active HER 2 transgene {2}. This model has been crossed with a strain with a floxed PTEN allele {2} and studies are currently under way to explore the role of PTEN in AZD-8931 resistance.

Citation Format: Helen Creedon, Morwenna Muir, Larry Hayward, Valerie Brunton. Development and characterisation of AZD-8931-resistant HER-2 positive breast cancer cells. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 4453. doi:10.1158/1538-7445.AM2013-4453
Abstract 4462: Resistance to selective kinase inhibitors upon epithelial to mesenchymal transition.
Authors: Wilson Catherine R. , Nicholes Katrina , Bustos Daisy , Lin Eva , Shi Lily , Kirkpatrick Donald , Settleman Jeffrey
Published: August 2014

Epithelial to mesenchymal transition (EMT) is a pivotal mechanism contributing to cancer metastasis and has been associated with resistance to multiple cancer therapies including targeted kinase inhibitors (TKIs). EMT has been associated with an acquired resistance to the EGFR TKI erlotinib independent of known resistance mechanisms such as secondary mutations T790M or MET amplification. RTK-addicted cancer cell lines that are induced to undergo EMT with exogenous TGF-β become resistant to their appropriate TKI. In vitro-based assays determined that the resistance is not due to exogenous TGF-β, drug efflux, or autocrine/paracrine growth factor signaling. To identify potential therapeutic vulnerabilities specifically within the mesenchymal, TKI resistant cells, we performed a small molecule screen of approximately 200 agents using the EGFR mutant non-small cell lung cancer (NSCLC) HCC827 cell line and its corresponding TGF-β-induced mesenchymal derivative line. This screen revealed that the mesenchymal cells are cross-resistant to a variety of small molecules, including TKIs and chemotherapeutic agents. However, a small number of agents showed selective growth inhibitory activity against the mesenchymal cells, with the most potent being the dual Brc-Abl and Src inhibitor, dasatinib. Within the parental HCC827 cell line, we detected a non-proliferating vimentin positive sub-population of cells. Interestingly, when the parental cell line was co-treated with erlotinib and dasatinib the entire cell population was killed and drug-resistant clones failed to emerge after prolonged treatment. To determine the mechanism underlying the resistance observed within the mesenchymal cells a proteomic analysis was undertaken, which demonstrated that the focal adhesion kinase, FAK, is the most abundant differentially phosphorylated protein in the resistant mesenchymal cells that is specifically suppressed by dasatinib. However, specific gene knock-down of FAK was not sufficient to kill the mesenchymal cells or revert their sensitivity to Erlotinib suggesting that FAK alone is not required to maintain resistance upon EMT. These findings identify dasatinib as a potential therapeutic for treatment of erlotinib resistance associated with EMT.

Citation Format: Catherine R. Wilson, Katrina Nicholes, Daisy Bustos, Eva Lin, Lily Shi, Donald Kirkpatrick, Jeffrey Settleman. Resistance to selective kinase inhibitors upon epithelial to mesenchymal transition. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 4462. doi:10.1158/1538-7445.AM2013-4462
Abstract 4467: Targeting both PI3K/mTOR and EGFR pathways leads to synergistic anti-tumor activity in erlotinib resistant non-small-cell lung cancers.
Authors: Mehta Pramod P. , Baxi Sangita M. , Walls Marlena , Chen Stella , Cheng Hengmiao , Li Gang , Smeal Tod , Yin Min-Jean
Published: August 2014

NSCLCs with EGFR mutations, such as a deletion in exon 19 (del E746-A750) or point mutation in exon 21 (L858R), are sensitive to TKI (gefitinib and erlotinib) treatments. However, acquired resistance to TKI therapy occurs in patients after 12-14 months. Approximately 50% of these resistant patients have developed secondary (gatekeeper) T790M mutation in EGFR; many other resistance mechanisms also have been described including a PIK3CA mutation and PTEN deletion. In this study, we characterize a dual PI3K/mTOR inhibitor, PF-4979064, in combination with a pan-ErbB inhibitor, PF-299804 (dacomitinib) in erlotinib resistant NSCLC lines NCI-H1975 (harboring EGFR and PIK3CA mutation) and NCI-H1650 (harboring EGFR and PTEN deletion). As a clinically relevant concentration of PF-299804 only induces moderate anti-tumor activity in both H1975 and H1650 cells, PF-4979064 was added in a variety of cellular and animal studies to determine whether the combination was able to achieve a synergistic induction of anti-tumor activity. Results demonstrate that the combination of PF-4979064 and PF-299804 lead to a synergistic inhibition in cell proliferation and xenograft tumor growth in both the NCI-H1975 and NCI-H1650 models. Our results further suggest that there is a rationale to examine a potential clinical development plan combining the dual PI3K/mTOR inhibitor (PF-4979064) and dacomitinib (PF-299804) in NSCLC patients who have developed resistance to erlotinib and have a concomitant PIK3CA mutation or PTEN deletion.

Citation Format: Pramod P. Mehta, Sangita M. Baxi, Marlena Walls, Stella Chen, Hengmiao Cheng, Gang Li, Tod Smeal, Min-Jean Yin. Targeting both PI3K/mTOR and EGFR pathways leads to synergistic anti-tumor activity in erlotinib resistant non-small-cell lung cancers. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 4467. doi:10.1158/1538-7445.AM2013-4467
Abstract 4475: New water-soluble and stable N-mustard-benzeneconjugates with potent antitumor activity, BO-2094, generated via leadoptimization by bioisostere approach.
Authors: Su Tsann-Long , Tala Satishkumar , Ou Tai-Hsin , Tala Kiranben , Kakadiya Rajesh , Lin Yi-wen , Chen Chi-Wei , Lee Te-Chang
Published: August 2014

The water solubility of drug candidate plays an important determinant of the bioavailability and supports whether a drug candidate can be successfully developed for clinical application. Previously, we have synthesized a series of water-soluble N-mustards, in which the phenyl N-mustard pharmacophore is linked to a benzamide moiety containing a hydrophilic side-chain at the meta- or para-position of the carboxamide function via a urea spacer. Of these derivatives, the water-soluble BO-1055 HCl exhibits a broad spectrum of antitumor activity and potent therapeutic efficacy against various human solid tumor (such as breast MX-1, colon HCT-116, and prostate PC-3) xenografts. To optimize the antitumor activity of BO-1055 via structural modification by bioisostere approach, we synthesized a series of new N-mustard-benzene conjugates, in which the phenyl N-mustard pharmacophore is linked to a benzene moiety via a urea linker, which can reduce the reactivity of the reactive N-mustard moiety. The benzene ring contains a variety of ω-N,N-dialkylaminoalkylamide or ω-cyclicaminoalkylamide side-chains at the meta- or para-position of the ureido linker. The tertiary amino function on the side-chain can be converted into a variety of water-soluble salts with inorganic or organic acids. The newly synthesized conjugates were subject to antitumor studies both in vitro and in tumor xenograft model. The results showed that these water-soluble conjugates exhibit a broad spectrum of antitumor activity against a panel of human leukemia and solid tumor cell growth in culture. Among these derivatives, BO-2094 [N-(4-(3-(4-(bis(2-chloroethyl)amino)phenyl)ureido)phenyl)-2-(diethylamino)acetamide], was revealed to be more cytotoxic than BO-1055 in inhibiting various tumor cell growth in vitro. It also showed that this agent is more potent than BO-1055 against human colon HCT-116, prostate PC3, and lung cancer H460 xenografts in mice. Studies on the mechanism of action revealed that BO-2094 is able to induce DNA cross-linking and cell arrest at G2/M phase. The present investigations conclude that BO-2094, a new water-soluble N-mustard-benzene conjugated with more potent therapeutic effect than BO-1055, has high potential to be selected as a candidate for preclinical antitumor studies.

Citation Format: Tsann-Long Su, Satishkumar Tala, Tai-Hsin Ou, Kiranben Tala, Rajesh Kakadiya, Yi-wen Lin, Chi-Wei Chen, Te-Chang Lee. New water-soluble and stable N-mustard-benzeneconjugates with potent antitumor activity, BO-2094, generated via leadoptimization by bioisostere approach. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 4475. doi:10.1158/1538-7445.AM2013-4475
Abstract 448: Mechanisms involved in the tumor-induced thymic involution.
Authors: Carrio-Jardines Roberto , Iragavarapu-Charyulu Vijaya , Libreros Stephania , García-Areas Ramón A. , Torroella-Kouri Marta , Lopez Diana M.
Published: August 2014

The thymus is a central lymphoid organ critical for the development and maintenance of an effective peripheral T cell repertoire. Most important, it provides a specialized environment for the selection of rearranged clones that will function appropriately in the adaptive immune response. T cell maturation progresses through well-defined stages in which proliferation, differentiation, and apoptosis are central to the selection of a functional TCR repertoire. During mammary tumorigenesis, there is a profound thymus involution associated with a severe depletion of the most abundant subset of thymocytes, CD4+CD8+ double positive (DP) immature cells. Thymic involution has been observed in several model systems; including graft-vs-host disease, aging, and tumor development, however, the precise mechanisms involved in this phenomenon remain poorly defined. Previous results from our laboratory have reported that the severe thymic atrophy and impaired T cell development seen in mammary tumor bearers are associated with a profound decrease in thymus size accompanied by a disrupture of the normal thymic architecture, an arrest in at least two steps of T cell differentiation, and an increase in thymic apoptosis in tumor-bearers. In our studies we have used the murine D1-DMBA-3 mammary tumor model to elucidate the exact mechanisms associated to the tumor-induced impaired T cell development and thymic involution. We have found that the disruption in the thymic architecture of tumor bearers appears to be related to a downregulated expression of hepatocyte growth factor in the medullar zone of the thymus. Moreover, the progressive increase of apoptosis in thymocytes during the tumor development is associated to a downregulation of Bcl-xL and A1, two important molecules that control programmed cell death. Additionally, the impaired T cell development observed during the tumor-induced thymic involution is associated to a profound decrease of IL-7 and IL-15, two crucial cytokines involved in T cell development; a downregulation in the expression of most of the Jak/Stat signaling proteins; and an increased expression of several suppressor of cytokine signaling (SOCS) members. Our data provides the bases for understanding the mechanisms associated to the impaired T cell development and thymic involution present in the thymuses of tumor bearers.

Citation Format: Roberto Carrio-Jardines, Vijaya Iragavarapu-Charyulu, Stephania Libreros, Ramón A. García-Areas, Marta Torroella-Kouri, Diana M. Lopez. Mechanisms involved in the tumor-induced thymic involution. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 448. doi:10.1158/1538-7445.AM2013-448
Abstract 4485: Anticancer properties of novel rhenium compounds against human cancer cell lines.
Authors: Banerjee Hirendra N. , Vaughan Deidre , Medley Jewe , Hyman Gwyn , Krauss Christopher , Parson Carl , Mandal Santosh , Olczak Pola , Mbagu Michael , Kebulu Divine , Pramanik Saroj , Sarkar Fazlul
Published: August 2014

Cisplatin, carboplatin, oxaliplatin, and related metallodrugs are extensively being used in the treatment of a variety of cancers. Unfortunately these drugs are highly toxic and tumor becomes drug-resistance. These circumstances have led researchers to look for new cytotoxic agents that may exhibit less toxicity and devoid of drug resistance. It is believed that cisplatin and related drugs directly bind to genomic DNA through purine bases. Synthesis of new metallodrugs which does not follow the above mechanism of action might yield better drugs with less toxicity and devoid of drug resistance. Recently we have demonstrated that several anticancer rhenium compounds do not directly bind to DNA. We have synthesized numerous rhenium pentylcarbonato and acetylsalicylato complexes which include (CO)3(2,2’-Bipyridyl)ReOC(O)OC5H11 (PC-1), (CO)3(1,10-Phenanthroline)ReOC(O)OC5H11 (PC-2), (CO)3(5-Methyl-1,10-Phenanthroline)Re ReOC(O)OC5H11 (PC-3), (CO)3(2,9-Dimethyl-1,10-Phenanthroline)ReOC(O)OC5H11 (PC-4), (CO)3(5,6-Dimethyl-1,10-Phenanthroline)ReOC(O)OC5H11 (PC-5), (CO)3(4,7-Diphenyl-1,10-Phenanthroline)ReOC(O)OC5H11 (PC-6), (CO)3(2,9-Dimethyl-4,7-Diphenyl-1,10-Phenanthroline)Re ReOC(O)OC5H11 (PC-7), (CO)3(2,2’-Bipyridyl)ReOC(O)C6H4·C(O)OCH3 (ASP-1), (CO)3(1,10-Phenanthroline)ReOC(O)C6H4·C(O)OCH3, (ASP-2), (CO)3(5-Methyl-1,10-Phenanthroline)ReOC(O)C6H4·C(O)OCH3 (ASP-3), (CO)3(2,9-Dimethyl-1,10-Phenanthroline)ReOC(O)C6H4·C(O)OCH3 (ASP-4), (CO)3(5,6-Dimethyl-1,10-Phenanthroline)ReOC(O)C6H4·C(O)OCH3 (ASP-5), (CO)3(4,7-Diphenyl-1,10-Phenanthroline)ReOC(O)C6H4·C(O)OCH3 (ASP-6), (CO)3(2,9-Dimethyl-4,7-Diphenyl-1,10-Phenanthroline)ReOC(O)C6H4·C(O)OCH3 (ASP-7). The anticancer properties of the compounds were evaluated using human prostate, alveolar lung, brain, colon, and leukemia cancer cell lines and normal bone marrow cell lines. The results of this study demonstrate that these complexes have significant anticancer properties. Therefore, these complexes can potentially find applications in the treatment of these cancers.

Acknowledgment. The work at MSU was partially supported by grants from the National Institutes of Health (Grant No. G11HD038439) and Nuclear Regulatory Commission (Grant No. NRC-HQ-12-G-27-0086). The work at ECSU-UNC was partially supported by grant from the Department of Energy (TMCF/DOE grant).

Citation Format: Hirendra N. Banerjee, Deidre Vaughan, Jewe Medley, Gwyn Hyman, Christopher Krauss, Carl Parson, Santosh Mandal, Pola Olczak, Michael Mbagu, Divine Kebulu, Saroj Pramanik, Fazlul Sarkar. Anticancer properties of novel rhenium compounds against human cancer cell lines. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 4485. doi:10.1158/1538-7445.AM2013-4485
Abstract 4492: Structure-activity relationship study anti-microtubule agents targeting the colchicine site on tubulin that circumvent drug resistance.
Authors: Gangjee Aleem , Xiang Weiguo , Mooberry Susan L. , Hamel Ernest
Published: August 2014

The vinca alkaloids and taxanes are successful antitumor agents. However, drug resistance limits their clinical utility in cancer chemotherapy. Overexpression of P-glycoprotein (Pgp) and expression of the β-tubulin subtype, β-III tubulin, are two clinically established drug resistance mechanisms that reduce the effectiveness of these agents. In 2010, we reported that the 6-CH3 cyclopenta[d]pyrimidine scaffold affords water soluble antimitotic agents targeting the colchicine site on tubulin. Molecular modeling and docking studies of the parent compound in the X-ray crystal structure of tubulin (PDB: 1SA0) suggested that the N4-CH3 moiety involved in hydrophobic interactions with the side chain C of Lysβ254, Alaβ250 and Leuβ248. However, this binding pocket in tubulin is relatively large. We designed a variety of N4-alkyl substitutions to determine optimal size of the substituent at the N4-position for these hydrophobic interactions. Among the different substitutions at the N4 were n-propyl, i-propyl and cyclopropyl. These compounds inhibited the growth of human breast cancer cell line MDA-MB-435 in culture, with IC50’s 130, 410, and 300nM, respectively. The previously reported methyl substituent at the N4-position is the most potent analog against these cancer cells, with IC50 of 10.6 nM. Thus, increasing the size of the N4-alkyl substituent caused a decrease in the potency of the analogs indicating that groups larger than methyl may be progressively detrimental to potency. This could be due to conformational restriction of various rotatable bonds in the molecule, lack of appropriate hydrophobic interactions with the colchicine site, and/or due to other factors such as transport into the tumor cells. The experiments to distinguish among these possibilities are undergoing.

Citation Format: Aleem Gangjee, Weiguo Xiang, Susan L. Mooberry, Ernest Hamel. Structure-activity relationship study anti-microtubule agents targeting the colchicine site on tubulin that circumvent drug resistance. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 4492. doi:10.1158/1538-7445.AM2013-4492
Abstract 45: Dynamic biochemical tissue analysis of P-selectin ligands expressed on colon cancer.
Authors: Martin Eric W. , Shirure Venktesh S. , Malgor Ramiro , Resto Vicente A. , Goetz Douglas J. , Burdick Monica M.
Published: August 2014

Selectin ligands are known to be upregulated in metastatic tumor cell lines, and growing evidence suggests selectin/selectin-ligand interactions mediate the adhesion of circulating tumor cells to distant sites. Thus, novel methods of characterizing selectin ligands expressed on human tissue may serve as valuable assays with significant diagnostic and prognostic potential. Because the kinetic and tensile properties of selectin/selectin-ligand bonds are influenced by local physiological conditions, i.e., wall shear stress due to hydrodynamic force, traditional immunohistochemical approaches cannot adequately detect selectin ligands. That is, though immunohistochemistry is very successful in identifying high affinity interactions, selectin/selectin-ligand interactions exhibit high affinity only when the external force applied on the bond is at an optimal value. This affinity is considerably weaker when applied force on the bond is significantly larger than this optimal value, or else is low or zero, as in traditional immunohistochemistry. Therefore, we have developed a method for detecting selectin ligands expressed on human tissue using a dynamic approach that allows for precise control of the force applied to the bonds between probe and target molecules. More specifically, we conjugated recombinant P-selectin to polystyrene microspheres and perfused this probe over tissue sections of colon cancer - which is known to express P-selectin ligands. Selectin/selectin-ligand adhesive interaction in the form of microsphere rolling on tissue was observed, and specific interaction was confirmed using 10 mM EDTA as a negative control. Increased probe surface coverage (i.e., higher density of P-selectin molecules coated on the surface of the microspheres) resulted in increased interaction with colon cancer tissue. In addition, rolling velocities measured between physiological wall shear stresses 0.25-2.0 dyne/cm2 indicated adhesive interaction of the selectin-conjugated probe with ligands in colon cancer tissues was stabilized at 0.75 dyne/cm2. Analysis of distinct regions within colon cancer tissue sections subjected to this dynamic biochemical tissue analysis revealed different levels of microsphere adhesion in discrete areas, evidence of heterogeneous cellular expression of P-selectin ligands. Taken together, these results demonstrate that functional P-selectin ligands are detectable using dynamic biochemical tissue analysis.

Citation Format: Eric W. Martin, Venktesh S. Shirure, Ramiro Malgor, Vicente A. Resto, Douglas J. Goetz, Monica M. Burdick. Dynamic biochemical tissue analysis of P-selectin ligands expressed on colon cancer. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 45. doi:10.1158/1538-7445.AM2013-45
Abstract 4503: Novel curcumin loaded magnetic nanoparticles for pancreatic cancer treatment.
Authors: Yallapu Murali M. , Ebleling Mara C. , Khan Sheema , Chauhan Neeraj , Gupta Brij K. , Sundram Vasudha , Jaggi Meena , Chauhan Subhash C.
Published: August 2014

Curcumin (CUR), a naturally occurring polyphenol derived from the root of Curcuma longa, has demonstrated potent anti-cancer and cancer prevention activity in a variety of cancers. However, the clinical translation of curcumin has been significantly hampered due its extensive degradation, suboptimal pharmacokinetics and poor bioavailability. To address these clinically relevant issues, we have developed a novel curcumin loaded magnetic nanoparticle (MNP-CUR) formulation. Herein, we have evaluated the in vitro and in vivo therapeutic efficacy of this novel MNP-CUR formulation in pancreatic cancer. Human pancreatic cancer cells (HPAFII and Panc-1) exhibited efficient internalization of the MNP-CUR formulation in a dose dependent manner. As a result, MNP-CUR formulation effectively inhibited growth of HPAFII and Panc-1 cells in cell proliferation and colony formation assays. Similarly, the MNP-CUR formulation suppressed pancreatic tumor growth in an HPAFII xenograft mice model and improved mice survival by delaying tumor growth. The growth inhibitory effect of MNP-CUR formulation was correlated with the suppression of PCNA, Bcl-xL, Mcl-1, MUC1, collagen I and enhanced membrane β-catenin expression. Interestingly, our MNP-CUR formulation did not show any sign of hemotoxicity and stable after incubation with human serum proteins. Additionally, our MNP-CUR formulation improved serum bioavailability of curcumin in mice up to 2.5 fold as compared to curcumin in Tween-20. Furthermore, biodistribution studies of our MNP-CUR formulation demonstrate a significant amount of formulation was able to reach the pancreatic xenograft tumor(s) which suggests its clinical translational potential. In conclusion, our study suggests that our novel MNP-CUR formulation can be valuable for the treatment of pancreatic cancer.

Citation Format: Murali M. Yallapu, Mara C. Ebleling, Sheema Khan, Neeraj Chauhan, Brij K. Gupta, Vasudha Sundram, Meena Jaggi, Subhash C. Chauhan. Novel curcumin loaded magnetic nanoparticles for pancreatic cancer treatment. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 4503. doi:10.1158/1538-7445.AM2013-4503
Abstract 4520: Nanotechnology based drug delivery in childhood leukemia therapy: A novel approach to reduce side-effects.
Authors: Krishnan Vinu , Xu Xian , Barwe Sonali , Yang Xiaowei , Waldman Scott A. , Mason Robert W. , Jia Xinqiao , Rajasekaran Ayyappan K.
Published: August 2014

Despite attaining 5-year survival rates of 90%; more than 60% of pediatric cancer survivors are affected by at-least one life threatening event in their lifetime. Childhood leukemia is currently treated with a combination of chemotherapeutics that are effective in combating the disease. However, these drugs also affect the normal growing cells in children causing devastating side-effects. The goal of this study is to develop nanosized drug delivery formulations that deliver drugs specifically to leukemic cells and ultimately reduce treatment related side-effects in children. Multi-step chemical transformations were employed to construct amphiphilic block copolymers consisting of hydrophilic polyether (PEG) and hydrophobic polyester (PCL) bearing pendent cyclic ketals. The functional block copolymers self-assemble into micelles with a core-shell architecture comprising a segregated PCL core that encapsulates the steroid drug (Dexamethasone) and a sterically stabilized PEG shell that provides a platform to conjugate targeting moieties. Dexamethasone (Dex) and fluorescent-dye encapsulated nanoparticles (NPs) were formulated by a nanoprecipitation method. The size and morphology of all formulations were analyzed by dynamic light scattering (DLS) and transmission electron microscopy (TEM) methods. The non-toxic nature of the blank-NPs was confirmed both in vitro and in vivo. The drug encapsulated NPs (Dex-NPs) are endocytosed into leukemic cells and induced cytotoxicity similar to that of free Dex, but at reduced doses. The Dex-NPs significantly improved survival in preclinical mouse models of leukemia. A second generation drug encapsulated targeted NPs with transferrin as the targeting moiety improved NP uptake in leukemic cells by comparison to non-targeted NPs. The demonstrated efficacy of such novel nanotherapeutic systems in vitro and in pre-clinical mouse models of acute leukemia have provided the foundation to successfully create novel therapeutic delivery systems that target and treat pediatric hematological malignancies with enhanced efficacy and reduced toxicity.

Citation Format: Vinu Krishnan, Xian Xu, Sonali Barwe, Xiaowei Yang, Scott A. Waldman, Robert W. Mason, Xinqiao Jia, Ayyappan K. Rajasekaran. Nanotechnology based drug delivery in childhood leukemia therapy: A novel approach to reduce side-effects. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 4520. doi:10.1158/1538-7445.AM2013-4520