bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract C81: Preclinical evaluation of riluzole for the treatment of mantle cell lymphoma
Authors: Medina Daniel , Zheng Laura , Rafanan Marites , Goydos James , Strair Roger 
Published: June 2012

Abstract
Purpose: Emerging evidence suggests a role for glutamate and its receptors in the pathogenesis of several forms of cancer. Investigators from our institution have recently shown that the metabotropic glutamate receptor 1 plays a significant role in the pathogenesis of melanoma and that inhibition of this pathway by the glutamate release inhibitor Riluzole results in suppression of cell growth. In this study we test the hypothesis that inhibition of metabotropic glutamate receptors by Riluzole in mantle cell lymphoma cells will result in a reduction of cell proliferation/survival.
Experimental Design: Mantle cell lymphoma (MCL) cell lines (MINO, JEKO and Rec-1) were treated with several concentration of the glutamate release inhibitor Riluzole. Samples were collected after 24, 48 and 72 hours of treatment and evaluated for cell viability and cell number by trypan blue exclusion, and cell proliferation and cell cycle analysis by flow cytometry. Apoptosis was evaluated by PARP cleavage and staining for Annexin V.
Results: All three MCL cell lines treated with Riluzole demonstrated a significant decrease in cell number and cell viability with an IC50=25uM. MCL cells treated with Riluzole showed a block in S and G2/M of the cell cycle followed by apoptosis. Apoptosis was confirmed by annexin V expression and by PARP cleavage.
Conclusions: Our date demonstrates that glutamate blockade with Riluzole results in the inhibition of mantle cell lymphoma proliferation, cell viability and the induction of cell cycle arrest at S and G2/M phases of the cell cycle. In addition, we show that the loss of cell viability is due to the activation of the apoptotic pathway. These preliminary findings suggest that expression of metabotropic glutamate receptors may be important in the pathogenesis and that targeting this pathway may provide a novel and effective therapy.
Citation Information: Mol Cancer Ther 2009;8(12 Suppl):C81.
Abstract C86: FGFR inhibition potentiates the effect of conventional chemotherapeutic agents in endometrial cancer cells
Authors: Byron Sara A. , Gartside Michael G. , Pollock Pamela M. 
Published: June 2012

Abstract
Endometrial cancer is the most common gynecological malignancy and the fourth most common cancer in women in the United States. Most women present with early stage disease confined to the uterus and thus have a favorable prognosis. However, for the subset of women who present with advanced disease or that recur, prognosis is poor, with a median survival after recurrence of 10 months, reflecting a lack of effective treatment options. We identified activating mutations in the fibroblast growth factor receptor 2 (FGFR2) receptor tyrosine kinase in 10–15% of endometrial tumors, and hypothesized that FGFR inhibition may be a viable therapeutic option for patients with FGFR2 mutation positive tumors. Indeed, we have shown that treatment of FGFR2 mutation positive endometrial cancer cell lines with PD173074, a pan-FGFR small molecular inhibitor, induces cell death both in vitro and in vivo. We have shown this cell death is caspase-independent, raising the possibility that combination of an FGFR inhibitor with chemotherapeutic agents may exhibit synergistic activity due to their non-redundant mechanisms of action. Moreover, as FGF ligand expression has been associated with chemoresistance and poor prognosis in a number of other cancer types, including lung, breast, ovarian, prostate, and head and neck carcinomas, we hypothesized that FGFR inhibition may also sensitize wildtype FGFR2 endometrial cancer cell lines to chemotherapeutic agents. We therefore sought to evaluate whether FGFR inhibition synergizes with conventional chemotherapeutic agents in endometrial cancer. Using combination index and Bliss additivity analysis, we evaluated whether FGFR inhibition potentiated the effect of paclitaxel and doxorubicin in a panel of FGFR2 mutant and non-mutant endometrial cancer cell lines. FGFR2 mutation status did not alter sensitivity to either chemotherapeutic agent alone. The combination of PD173074 with paclitaxel or doxorubicin showed synergistic activity in all three FGFR2 mutant cell lines. In addition, though non-mutant cell lines were resistant to FGFR inhibition alone, the addition of PD173074 potentiated the effect of paclitaxel and doxorubicin in a subset of FGFR2-wildtype cell lines tested. Together these data suggest a therapeutic benefit to combining an FGFR inhibitor with standard chemotherapeutic agents, and, importantly, this may extend to patients whose tumors possess wildtype FGFR2.
Citation Information: Mol Cancer Ther 2009;8(12 Suppl):C86.
Abstract C9: Utility of serological apoptosis biomarkers: Assessment in a phase II study of zibotentan (ZD4054) in patients with hormone-resistant prostate cancer
Authors: Malone Mike , Mann Helen , Growcott Jim , Butt Fouziah , Moore David 
Published: June 2012

Abstract
Serological apoptosis biomarkers, cytokeratin-18 (M65), cleaved cytokeratin 18 (M30) and nucleosomal DNA (nDNA) are frequently elevated above normal levels in patients with various cancers and are considered to reflect tumor burden.1 Moreover, these biomarkers appear to be dynamically modulated by cytotoxic therapy capable of inducing tumor response.2–4 We retrospectively investigated whether a non-cytotoxic agent, zibotentan, had any impact on serological levels of these apoptosis biomarkers. Zibotentan has shown survival benefit in hormone-resistant prostate cancer (HRPC) patients despite the lack of RECIST based responses.5
Serological samples were obtained from consented patients before the start and at 12 weeks after the assigned randomized treatment (placebo, zibotentan 10 or 15 mg daily oral doses) and were processed for M30, M65 and nDNA concentrations. Approximately 59% (N=184) and 42% (N=82) of the study intent to treat population (N=312 and N=195) had M30 values at baseline and at week 12, respectively. Similar numbers of M65 and nDNA values were available for analysis.
No consistent dose-related trends in mean percentage change from baseline or at 12 weeks were observed for any of the biomarkers. However, there were trends towards reductions for M30 in patients receiving zibotentan 10 mg (−11%, 95% confidence interval [CI] −24%, +6%) and for nDNA in patients receiving zibotentan 15 mg (−15%, 95% CI −44%, +30%). Applying a Cox proportional hazards regression model for overall survival (OS) and including a treatment factor and baseline covariates, stratifying the apoptosis biomarkers on the basis of ‘high’ or ‘low’ concentrations (based on median baseline values) revealed a statistically significant difference for OS ± M65 (P value = &lt;0.001). M30 and nDNA were without significant relationship.
The M65 data suggest a potential utility for this marker in prognosis. Further evaluation of the clinical relevance of these findings is warranted with access to a larger patient dataset. The ongoing phase III clinical trials for zibotentan in HRPC patients will provide this opportunity.
Citation Information: Mol Cancer Ther 2009;8(12 Suppl):C9.
Abstract C92: DNA methylating combi-molecule ZRS1 induces p53 and blocks the epidermal growth factor (EGFR)-activated pathways in EGFR-expressing human tumor cells: Relationship to O6-methylguanine DNA methyltransferase (MGMT) status
Authors: Huang Ying , Rachid Zakaria , Qiu Qiyu , Na Ning , Jean-Claude Bertrand J. 
Published: June 2012

Abstract
The combi-targeting concept seeks to design single molecules that combine an EGFR tyrosine kinase inhibitor with a DNA damaging agent. One such molecule, ZRS1 contains an EGFR tyrosine kinase targeting quinazoline moiety and a methyltriazene-based DNA-damaging function capped with an acetoxymethyloxy group that stabilizes the 1,2,3-triazene chain. Here, we analyzed the DNA damage response, the MAPK and the PI3K pathways in response to the dual action of ZRS1. We also determined whether its mixed EGFR-DNA targeting property could enhance its potency in tumor cells expressing the O6-methylguanine DNA methyltransferase (MGMT), a DNA repair enzyme that confers resistance to methylating agents. The growth inhibitory potency of ZRS1 was tested in a panel of 8 human tumor cell lines with varied levels of EGFR and MGMT. ZRS1 was more potent than the clinical methylating agent temozolomide (TEM) in all the cell lines tested, including the lung cancer (A549, A427 and Calu-1), colon cancer [HT29, HCT116 and HCT116 (p53−/−)], and breast cancer cell lines (MDA-MB-468 and MDA-MB-231), regardless of their MGMT status. However, its potency was in the same range as or less than ZD1839, a single-targeted EGFR inhibitor, against MGMT-proficient cells. In the MGMT-deficient cells or MGMT-proficient cells in which MGMT levels were depleted with O6-benzylguanine, its potency was superior to that of ZD1839 or TEM. ZRS1 exhibited IC50 of 0.5 µM in the A427 cell line, a value that was 25-fold lower than that of TEM, 12-fold lower that of ZD1839 and 15-fold lower than that equi-toxic and equimolar combinations of ZD1839+TEM. The two lung cancer cell lines A549 (MGMT+) and A427 (MGMT−) were selected for analyzing the cell signaling pathways underlying the growth inhibitory effect induced by the dual effects of ZRS1. The results showed that: 1. ZRS1 strongly inhibited EGFR phosphorylation in both cell lines and this translated into inhibition of ERK1/2, AKT, Bad S112 and Bad S136 phosphorylation in both cell lines 2. ZRS1 inflicted significant levels of genomic DNA damage and induced p53 in a dose-dependent manner in both cell lines. Likewise Bax and GADD45 were also induced in both cell lines. The results in toto suggest that in the presence of MGMT, ZRS1 primarily acts as an EGFR inhibitor with no significant effect of its DNA damaging component. In contrast, in the absence of MGMT, its ability to (a) activate the p53 pathway (b) block the MAPK and PI3K pathways, translates into significant cell-killing. Further studies with plasmid transfection either to knockdown endogenous MGMT or express exogenous MGMT are ongoing to elucidate the mechanism underlying the suppression of the potency of ZRS1 by MGMT.
Citation Information: Mol Cancer Ther 2009;8(12 Suppl):C92.
Abstract A100: Pemetrexed-induced uracil accumulation is an importatn source of DNA damage in UNG deficient cells, contributing to hematologic toxicity.
Authors: Weeks Lachelle D. , Zetner Gabriel , Scacheri Peter , Liu Lili , Gerson Stanton L. 
Published: June 2012

Abstract
Pemetrexed is a multi-target antifolate that has proven activity against several solid tumors. Dose limiting myelosuppression and acquired resistance are major challenges to pemetrexed and antifolate chemotherapy regimens. We have previously shown that resistance to pemetrexed in human cancer cells can be overcome via inhibition of DNA base excision repair (BER), the major pathway responsible for the resolution of uracil in DNA. To understand the implications of UNG deficiency in vivo, we have investigated the impact of UNG deficiency on whole animal response to pemetrexed. Here, we illustrate that pemetrexed treatment induces more significant reduction in bone marrow cell numbers and relatively low peripheral lymphocyte counts in UNG−/− mice compared to UNG+/+ littermates. Compared to wild-type cells, UNG−/− MEFs also show reduced viability and increased cell death in response to pemetrexed. Hematopoietic cell sensitivity was mirrored by increased pemetrexed cell killing in UNG mutant human lymphoblastoid cells, derived from patients with biallelic inactivating mutations in the UNG gene. Cellular sensitivity is characterized by reduced nucleotide incorporation, arrest in S-phase of the cell cycle, and induction of apoptosis. Pemetrexed treatment of UNG−/− cells also causes robust induction of γ-H2AX, a surrogate marker of DNA double strand breaks. Through γ-H2AX ChIP-sequencing we provide the first direct evidence that DNA double strand breaks are located specifically at AT(U) rich sequences, directly implicating uracil accumulation in the formation of double strand breaks following pemetrexed treatment. UNG deficient cells showed no differential sensitivity to cisplatin or temozolomide, two drugs unrelated to uracil accumulation. Moreover, through thymidine supplementation, we were able to partially reverse the pemetrexed-mediated induction of DNA damage markers, including γ-H2AX and protect UNG−/− cells from cell death, further supporting a uracil-mediated mechanism of cytotoxicity in UNG−/− cells. In sum, these data suggest that the accumulation of uracil in the DNA of hematopoietic cells drives myelosuppression and lymphocyte toxicity. Mechanistically, our data support a previously underappreciated role for uracil accumulation, UNG activity and the BER pathway in the determination of cellular sensitivity to pemetrexed and suggest UNG expression may be an important predictor of adverse events, such as myelosuppression in individuals receiving pemetrexed.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2011 Nov 12-16; San Francisco, CA. Philadelphia (PA): AACR; Mol Cancer Ther 2011;10(11 Suppl):Abstract nr A100.
Abstract A104: Removal of uracil by uracil DNA glycosylase limits pemetrexed cytotoxicity: Overriding the limit with methoxyamine (TRC102) to inhibit base excision repair.
Authors: Bulgar Alina , Weeks Lachelle D. , Miao Yanling , Yang Shuming , Xu Yan , Guo Chunguang , Markowitz Sanford , Gerson Stanton L. , Liu Lili 
Published: June 2012

Abstract
Uracil DNA glycosylase (UDG) is a conserved DNA repair protein existing in all types of human cells. Since UDG specifically removes uracil bases from DNA, its repair activity determines cell sensitivity to anticancer agents that are capable of introducing uracil into DNA. We studied the participation of UDG in response to pemetrexed-induced incorporation of uracil into DNA using isogenic human tumor cell lines with or without UDG (UDG+/+/UDG−/−). Results revealed that UDG−/− cells were very sensitive to pemetrexed. Cell killing by pemetrexed was associated with genomic uracil accumulation, stalled DNA replication, and catastrophic DNA strand breaks. In contrast, UDG+/+ cells were &gt;10 times more resistant to pemetrexed due to a rapid removal of uracil from DNA, generating abasic sites (AP sites). Resultant AP sites were efficiently repaired by base excision repair (BER) so that they contributed little to cell death. However, addition of the BER inhibitor methoxyamine (TRC102) synergistically enhanced the cytotoxicity of pemetrexed in UDG proficient cells. MX bound covalently to AP sites to form unrepairable MX-bound AP sites, thereby inhibiting the BER pathway. Importantly, we identified that MX-bound AP sites induced cell death by inactivating UDG and poisoning topoisomerase II. These two genes are highly expressed in lung cancer cells in comparison with normal bone marrow cells. Thus, targeting UDG/BER to enhance pemetrexed cytotoxic effects is a target-based strategy that selectively mediates cytotoxicity on cancer cells through a synthetic lethal mechanism.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2011 Nov 12-16; San Francisco, CA. Philadelphia (PA): AACR; Mol Cancer Ther 2011;10(11 Suppl):Abstract nr A104.
Abstract A106: Investigation of 5-fluorodeoxycytidine with tetrahydrouracil as a demethylation regimen in solid tumors.
Authors: Kinders Robert J. , Wang Lihua , Kummar Shivaani , Khin Sonny , Balasubramanian Priya , Zhu Weimin , Parchment Ralph E. , Newman Edward , Tomaszewski Joseph E. , Doroshow James H. 
Published: June 2012

Abstract
Methylation-induced silencing of gene promoters is widely documented in numerous cancer types, and the anti-tumor activity of agents that target this phenomenon has established DNA methyltransferase (DNMT1) as a valid drug target. We have investigated the combination of 5-fluorodeoxycytidine with Tetrahydrouridine (FdCyd + THU) in vitro and in vivo using continuous exposures up to 12 weeks. Supplementation of the medium with Deoxythymidine (10 μM) was required to prevent FdCyd cytotoxicity and allow sufficient time for demethylation to occur. Decitabine was used as the positive control throughout the evaluation. The bladder cancer line EJ6 was sensitive to FdCyd + THU, as evidenced by an increase in cell doubling time, a decrease in LINE1 methylation, and an initial decrease in total DNMT1 concentrations, determined with a newly-developed, quantitative two-site immunoassay. The triple negative breast cancer line MDA-MB-231 was resistant to the regimen, as assessed by all three criteria. The mechanism of this combination regimen in tumor cells isolated from paracentesis specimens from patients enrolled on an NCI-supported Phase 1 clinical trial of FdCyd + THU; and was confirmed by finding changes in both DNMT1 levels and LINE1 methylation. Upregulation of expression of p16 (INK4a), but not GSTP1 or RASSF1, was observed in EJ6 cells following FdCyd + THU by Western blotting. An immunofluorescence assay for p16 expression in circulating tumor cells (CTCs) has been developed and implemented in the Phase 1 trial. The ongoing Phase 2 trial of this regimen will include measurements of DNMT1 and LINE1 methylation in tumor biopsies and p16 in CTCs to directly assess drug effect on the DNMT1 target.
This Research has been funded in part with federal funds from the National Cancer Institute, National Institutes of Health, under Contract No. HHSN261200800001E and NCI RAID Project #266 Grant.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2011 Nov 12-16; San Francisco, CA. Philadelphia (PA): AACR; Mol Cancer Ther 2011;10(11 Suppl):Abstract nr A106.
Abstract A13: Characterization of CRC primary explant models in comparison to standard human tumor cell-line-derived CRC xenografts.
Authors: Alferez Denis G. , Brown Helen , Dry Jonathan R. , Runswick Sarah , James Neil , McWalter Gael , Whiteley Jessica , Revill Mitch , Beran Garry , Farren Matthew , Smith Neil R. , Hedge Phillip , Barry Simon , Wedge Stephen R. , Wilkinson Robert W. 
Published: June 2012

Abstract
Primary tumor xenograft models (PTX) are established in immunodeficient mice by implantation of material directly from patient tumors. These models are propagated in vivo so that they are not subjected to additional selection pressures within tissue culture. The models reputedly reflect a greater genetic diversity of disease than can be recapitulated within tumor cell line derived xenografts and may have morphological differences. Consequently, such models may be of greater relevance for the evaluation of drug efficacy.
To verify differences versus cell line derived xenograft models, we have examined samples of 42 CRC PTX models, derived from Dukes stage A-D tumor samples, which were obtained from European contract research organisations) Characterisation included analysis of common genetic mutations (KRas, BRAF, PI3Ka, PTEN, P53 and APC), mRNA expression via microarray platforms (Affymetrics HG_U133_plus_2), high-throughput RT-PCR of specific probes (mouse and human) to examine stromal genes, and the activation of particular proteins using reverse phase antibody arrays and immunohistochemistry. Comparisons were made with 6 commonly used CRC cell line derived xenografts.
The PTX models overall represent a broader range of molecular pathology - for example the inclusion of wild-type Kras tumors. Histopathological characterisation also confirmed that the PTX models have a higher stromal content that is routinely observed in cell line derived xenografts, and a more complex morphology with higher tumor cell differentiation.
PTX models may potentially complement drug discovery activities by providing a wider platform in which to test preclinical hypotheses - based upon a defined biological mechanism and/or a genetic determinant of sensitivity.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2011 Nov 12-16; San Francisco, CA. Philadelphia (PA): AACR; Mol Cancer Ther 2011;10(11 Suppl):Abstract nr A13.
Abstract A147: EZN-3920, a HER3 antagonist, enhances the antitumor effect of gefitinib and lapatinib in xenograft models.
Authors: Wu Yaming , Li Qi , Wang Maoliang , Qu Zhengxing , Kim Steven , Zhang Yixian , Greenberger Lee M. 
Published: June 2012

Abstract
Background: The HER family consists of four tyrosine kinase receptors designated as EGFR, HER2, HER3 and HER4. Numerous new studies now indicated that HER3 plays a critical role in cancer development since it 1) heterodimerizes with EGFR or HER2, 2) is a critical link to the PI3K/AKT axis, and 3) can mediate resistance to HER1/2-targeted therapeutics. Resistance to the tyrosine kinase inhibitors (TKIs), such as gefitinib and lapatinib, are associated with overexpression of HER3 ultimately leading to activation of the PI3K/AKT axis. Thus, it is a logical approach to combine agents capable of down modulating HER3 with TKIs. To this end, we have used an RNA antagonist of HER3, EZN-3920, to explore its ability to inhibit tumor growth and enhance the activity of HER1/2-directed therapeutics.
Methods: Tissue culture cells were treated with EZN-3920, a locked nucleic acid (LNA)-based oligonucleotide complementary to HER3. EZN-3920 was either added to tissue culture media (i.e. no transfection) in vitro or prepared in saline and given IV in vivo. Endpoints were measured by qRT-PCR, MTT, Western Blot analysis, Immunohistochemistry, and tumor size.
Results: EZN-3920 down modulated HER3 mRNA, protein expression, PI3K/AKT signaling, and inhibited tumor cell proliferation. In vivo systemic administration of EZN-3920 resulted in specific down-modulation of HER3 mRNA and protein expression, as well as blockade in PI3K/AKT signaling pathways in tumors derived from HCC827 lung carcinoma cells that was associated with tumor growth inhibition. Interestingly, the combination of EZN-3920 at 30 mg/kg (biweekly for 4 weeks, i.v.) and gefitinib at 15 mg/kg (5 times a week for two weeks, p.o) completely shrank established HCC827 tumors while either treatment alone only delayed tumor growth by 40–60%. Similarly, in BT-474-M1 breast carcinoma xenograft models, EZN-3920 in combination with lapatinib resulted in superior antitumor effect than either agent alone.
Conclusions: The studies suggest that the antitumor effects of gefitinib or lapatinib can be enhanced by HER3 down modulation in NSCLC and breast tumors, respectively. On-going studies will determine if tumors that are resistant to HER1/2 therapeutics will still respond to EZN-3920 alone or its combination with standard HER1/2 therapeutics.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2011 Nov 12-16; San Francisco, CA. Philadelphia (PA): AACR; Mol Cancer Ther 2011;10(11 Suppl):Abstract nr A147.