bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 2652: Formulation and pharmacokinetics of Lazaroid U-74389G (LAZ) liposomes in rats
Authors: Ibrahim Fady Makram L. , New Pamela , Chow Diana S-L
Published: February 2011

Purpose Lazaroid U74389G (LAZ) is a 21-aminosteroid that has a radioprotective and antioxidant effects. It prevents the damage in the tissues after radiation by a selective action on vascular endothelium cells in normal tissues. The aim of this study is to develop liposomal formulations of LAZ with favorable pharmacokinetic (PK) profiles for potential therapeutic merits in an animal model.

Methods Conventional (LipoB) and pegylated (LipoG) liposomes were prepared with various phosphatidylcholine: cholesterol ratios and lipid: LAZ ratio of 10:1. The liposomes were characterized with the size, charge and release profile. The PK study was performed in Sprague-Dawley rats. The rats were randomized into 3 groups (n=4 each) prior to the dosing of the formulations (LAZ solution, LipoB and LipoG) at a dose of 1 mg/kg by injection through the cannula at jugular veins. At pre-determined time points, blood samples were collected from the tail vein. The LAZ concentrations in plasma were quantified by a validated UPLC/MS/MS assay using Daidazine as the internal standard, with a lower limit of quantification (LLOQ) of 4 ng/ml for LAZ. The PK profiles were constructed by plotting the plasma concentration versus time and the PK parameters were derived using compartmental models of WinNonlin Ver 3.3 software.

Results The liposomal preparations with the least amount of cholesterol had the lowest Encapsulation Efficiency (EE=26%). However, an increase of cholesterol ratio up to 20% increased the EE up to 58%. The size of the liposomes was in the range of 90-118 nm. In in-vivo study, the plasma profile of the solution fits 1-compartment model while the liposomal formulations fit 2-compartment model. The solution group yielded a higher Cmax and faster clearance (4.27 μg/ml and 546 ml/hr) than those of LipoB and LipoG (0.97 and 2.03 μg/ml and 380 and 216 ml/hr, respectively). The t1/2's of LAZ from LipoB and LipoG were 5 folds of that from the solution (0.64 and 0.52 hr vs 0.10hr). The solution showed a significantly smaller AUC compared to those of LipoB and LipoG (0.56 μg.hr/ml vs. 0.79 and 1.42 μg.hr/ml, respectively). The volume of distribution was small for the solution compared to LipoB and LipoG (73 ml vs. 1173 and 589 ml, respectively). The half-lives of distribution and elimination, t1/2 α and t1/2 β, were comparable between LipoB and LipoG (0.22 vs. 0.16 hr and 3.17 vs. 2.55 hr, respectively).

Conclusion The liposomal formulations modified the pharmacokinetics of LAZ solution. The liposomal formulations resulted in a slower clearance and wider distribution of LAZ in-vivo compared to the solution. LAZ systemic exposures in rats after administration of LAZ liposomes were 1.4 −2.5 folds higher than that of solution.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2652.
Abstract 2654: Transferrin receptor targeting PRINT® nanoparticles: Chemotherapeutic-free nanomedicine for B-cell lymphoma
Authors: Tian Shaomin , Wang Jin , Petros Robby A. , Napier Mary E. , DeSimone Joseph M.
Published: February 2011

Transferrin receptor (TfR, CD71) is an essential protein involved in cellular iron uptake and regulation of cell growth. This study is to convert PRINT® nanoparticles to targeted drug delivery system by conjugating TfR ligands to particle surface, taking advantage of TfR overexpression on many types of malignant tissues. 200 nm × 200 nm cylindrical PRINT nanoparticles with poly(ethylene glycol)-based composition were fabricated and labeled with transferrin receptor antibody (mouse anti-human TfR mAb, clone OKT-9) or human transferrin (hTf) via biotin-avidin binding or direct chemical conjugation strategies. Nanoparticles coated with OKT9 or hTf, but not isotype control mouse IgG1 or bovine transferrin (bTf), showed highly specific TfR-mediated uptake by all human tumor cell lines tested in this study, including solid tumors and disseminating B cell lymphomas. Non-cancerous HEK293 cell that expresses low level of surface TfR, in contrast, took up particles at much lower rate during short exposure to TfR-targeting particles. The targeting efficiency was dependent on particle concentration, ligand density, particle dosing time and cell surface receptor level.

Interestingly, the PRINT nanoparticles coated with OKT9 or hTf showed little cytotoxicity on all solid tumor cell lines tested but were toxic to Ramos B-cell lymphoma. More than 70% of the Ramos cells were killed by OKT9 or hTf coated nanoparticles at a concentration of 100 µg/mL. In contrast, free OKT9 or hTf did not induce death of Ramos cells. There was a strong correlation between TfR ligand density on particle surface and cell viability. Elevated caspase 3 activity indicates the activation of apoptosis pathways upon particle treatment. Iron supplementation suppressed toxicity of NP-OKT9 but not NP-hTf, suggesting different mechanisms by which hTf and OKT9 exerts cytotoxicity on Ramos cells. Further study of cell death mechanism through DNA microarray analysis is under way.

Overall, we have shown that human transferrin and transferrin receptor antibodies can be useful targeting ligands for nanoparticle delivery to tumors. More importantly, non-toxic transferrin and TfR antibodies can be turned into a potential chemotherapeutic-free medicine for B-cell lymphoma through multiplexing with PRINT nanoparticles.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2654.
Abstract 2655: Apoptotic peptide hybrid for treatment of chemotherapy-resistant cancers
Authors: Kim Ji-seon
Published: February 2011

Resistance to chemotherapy is one of the major obstacles to successful cancer treatment. Many cancer patients develop metastatic cancers after responding to initial treatment, which are often refractory to chemotherapy, and remain incurable. Inhibition of apoptotic pathways due to up-regulation of anti-apoptotic elements, such as Bcl-2 and IAPs (inhibitors of apoptosis proteins) has been reported to account for the resistance to chemotherapeutic agents. Thus, it is critical to restore the inhibited apoptosis to re-sensitize the cancer to chemotherapy. In this study, we investigated whether a pro-apoptotic peptide and a proteasome inhibitor peptide can synergize to induce apoptosis in doxorubicin-resistant cancer cells in vitro. The pro-apoptotic peptide is a cationic amphipathic peptide which depolarizes mitochondrial membranes to release apoptosis initiators such as, cytochrom c and Smac/DIABLO to cell cytosols, which activate caspases, apoptosis executors by inhibiting IAPs (inhibitors of apoptosis proteins). MG132 (Z-Leu-Leu-Leu-CHO) has been reported to inhibit anti-apoptotic proteins including NF-[[Unable to Display Character: ĸ]]B and Bcl-2 family proteins to stimulate apoptosis. We hypothesized that when concurrently delivered to the same cells, KLA and MG132 would synergize to induce apoptosis in resistant cancer cells by acting on different stages of apoptotic pathways. To test this, we conjugated KLA and MG132 by forming acid-labile Schiff bases between ε-amino groups of lysines in KLA and the aldehyde group of MG132. We expected that the formed KLA-MG132 conjugates would be internalized into cells by pinocytosis then, dissociated in the acidic environment (pH 4 – 5) of lysosomes to release intact KLA and MG132. The conjugation efficiency was found to be ∼ 100%, as measured indirectly by quantifying amine groups of un-conjugated lysine residues by TNBS assay. The conjugation was confirmed further by determining the molecular masses of the formed conjugates by mass spectrometry after reducing the conjugates by NaBH4 to stabilize Schiff bases. The conjugates induced upto 50 % of cell death in doxorubicin-resistant human cancer cells at the concentration of 0.6 μM as determined by MTT assay meanwhile; un-conjugated MG132 and KLA were inactive at the same concentration. And, the levels of cytosolic cytochrome c were 2-fold greater in the cells treated with KLA-MG132 conjugates than in cells treated with MG132 alone. The levels of active caspase-3 were higher by up to 70 % in cells treated with KLA-MG132 conjugate than in cells treated with MG132 alone. In conclusion, we have observed that KLA and MG132 conjugated via Schiff base induced potent apoptosis in doxorubicin-resistant human cancer cell lines at sub-micromolar concentrations.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2655.
Abstract 2659: A thermally targeted carrier of p50 NLS peptide inhibits cancer cell proliferation by preventing NFκB nuclear translocation
Authors: Thomas Emily H. , Raucher Drazen
Published: February 2011

The application of rationally designed therapeutic peptides may improve outcomes in cancer treatment. These peptides hold the potential to directly target proliferative pathways and to inhibit their over-expression. The NFκB survival pathway is constitutively active in many cancers and plays a role in evading apoptosis. A p50 NLS-derived peptide has been shown to bind to the nuclear receptor and prevent NFκB translocation into the nucleus. This 10 amino acid peptide thus inhibits the transcriptional activation of NFκB's cellular targets that are implicated in cancer cell survival and metastasis.

By conjugating the p50 derived peptide to a thermally targeted carrier and a cell penetrating peptide, the specificity and stability of peptide delivery can be enhanced. The addition of a cell penetrating peptide, SynB1, to the N-terminus of ELP enhances the cellular uptake of the conjugated peptide, SynB1-ELP1-p50. Elastin like polypeptide (ELP) is an elastin derived biopolymer that undergoes a thermally-mediated phase transition. By applying an external heat source, mild hyperthermic conditions (41°C) can induce aggregation and therefore can be used to specifically target ELP to solid tumors in cancer therapy. Uptake studies indicate that hyperthermia increases the accumulation of flourescein-labeled SynB1-ELP1-p50 in MCF-7 cells by 3 fold as compared to SynB1-ELP1-p50 treatment without heat. In addition to providing a level of targeting specificity, as a macromolecule, ELP may increase the plasma stability of small therapeutic peptides, like p50, and therefore creates the potential for viable delivery in vivo.

Preliminary in vitro studies have demonstrated that two 1-hour treatments with 20μM of SynB1-ELP1-p50 inhibits cell proliferation by 20% and in combination with hyperthermia by 40%, in both MCF-7 and HeLa cell lines. No inhibitory effect was seen when the carrier control, SynB1-ELP1, was used. Confocal microscopy studies illustrate the predominantly cytoplasmic localization of rhodamine labeled SynB1-ELP1-p50 with some localization at the nuclear periphery. Immunofluorescence studies suggest that SynB1-ELP1-p50 may attenuate the nuclear translocation of NFκB following stimulation with TNF-α. Future studies will elucidate the anti-proliferative mechanisms of this conjugated peptide and quantify the inhibition of nuclear translocation of NFκB following treatment with SynB1-ELP1-p50.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2659.
Abstract 2667: Inhibition of CYP3A4 expression by camptothecin via blocking activation of pregnane X receptor
Authors: Chen Yakun , Tang Yong , Robbins Gregory Thomas , Nie Daotai
Published: February 2011

Individual variation in drug metabolism is a major cause of unpredictable side effects during cancer therapy. Drug metabolism is controlled by a class of orphan nuclear receptors (NRs), which regulate the expression of cytochrome 3A4 (CYP3A4), an enzyme metabolizing more than 60% of clinically used drugs. In our study, it was found that xenobiotic-mediated induction of CYP3A4 gene expression in primary human hepatocytes was inhibited by camptothecin (CPT) but not by its analogue, irinotecan (CPT-11). CPT exerted its effect by inhibiting the activation of NR, human pregnenolone X receptor (hPXR). In contrast, irinotecan was found to be an hPXR agonist in the same tests. CPT disrupted the interaction of hPXR with steroid receptor coactivator-1 (SRC-1) but had no effects on the formation of the hPXR and retinoid X receptor α (RXRα) heterodimer. Nor had it effects on the interactions between the regulatory complex and DNA responsive elements. CPT treatment resulted in delayed metabolism of nifedipine induced by rifampicin in human hepatocytes, suggesting a potential drug-drug interaction (DDI) between CPT and CYP3A4 metabolized drugs. The study found a novel potent hPXR antagonist and indicated the potential of a new class of compounds to control drug efficacies in cancer therapy.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2667.
Abstract 2671: Structural analysis of the inhibitory mechanism of AP24534, a pan-BCR-ABL inhibitor overriding the T315I gatekeeper mutation
Authors: Zhu Xiaotian , Zhou Tianjun , Shakespeare William C. , Huang Wei-Sheng , Commodore Lois , Metcalf Chester A. , Wang Yihan , Thomas Mathew , Sundaramoorthi Raji , Zou Dong , Sawyer Tomi K. , Clackson Tim , Dalgarno David C.
Published: February 2011

Although durable response in many chronic myeloid leukemia (CML) patients can be achieved by imatinib treatment, point mutations in the kinase domain of the BCR-ABL fusion protein can lead to drug resistance and relapse. Nilotinib and dasatinib, the two second generation Abl kinase inhibitors, are active against most imatinib resistant mutants with a few exceptions, particularly the T315I gatekeeper residue mutation. Using a structure-based approach we have identified AP24534, a molecule that potently inhibits the T315I mutant and all other mutants tested, thus acting as a pan-BCR-ABL inhibitor. To elucidate the basis for this unique profile of AP24534, we have used a combination of X-ray crystallographic and structure-activity relationship analysis on AP24534 and its analogs. The crystal structure of the T315I mutant Abl in complex with the inhibitor clearly demonstrates that AP24534 binds to Abl in a DFG-out binding mode with the ethynyl chemical moiety skirting the mutated gate-keeper residue avoiding steric clashes. The X-ray co-structures of both the wild type and the T315I mutant Abl, in conjunction with the SAR analysis, further reveal that AP24534 retains potency against the T315I and other imatinib-resistant ABL mutants through optimized multiple points of contact, balancing and distributing the overall binding affinity so that mutation-based disruption of one facet of the binding network results in only a slight reduction in binding affinity. Our structural analysis enables us to predict and rationalize the different degree of sensitivity of ABL point mutants to AP24534, and to understand how AP24534 can completely abrogate resistance in cell-based mutagenesis screens at relatively low concentrations. AP24534 is currently being investigated in a Phase I clinical trial in patients with refractory and resistant CML and other hematological malignancies.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2671.
Abstract 2674: Interaction of natural alkaloids with G-quadruplex structures: biophysical and pharmacological implications
Authors: Bianco Sara , Bazzicalupi Carla , Gratteri Paola , Bilia A. R. , Schwalbe H. , Richter C. , Palumbo Manlio , Sissi Claudia
Published: February 2011

DNA sequences rich in guanines can fold up to form peculiar structures, known as a G-quadruplex, deriving from pairing of four guanines by Hoogsteen-like hydrogen bonds. Nowadays, these structure(s) are being exploited as suitable targets for anti-cancer drug design. Indeed, G-quadruplexes can be formed at the telomers, the ends of human chromosomes as well as in the promoters of several important oncogenes such as c-myc, bcl-2, c-kit and VEGF. At physiological conditions an equilibrium between different conformations builds up. It has been shown that the interconversion between folded-unfolded conformation can be used by the cell to modulate the oncogene transcriptional state. Up-to-date, several classes of compounds have been tested and identified as efficient G-quadruplex binders. DNA recognition occurs mainly through stacking on a terminal G-tetrad, thus, these ligands share a general consensus structural motif based on a large flat aromatic surface. Several natural compounds characterized by cytotoxic activity present this structural motif. Here, we selected several structurally related natural derivatives of plant origin characterized by four fused rings with different degree of π electron delocalization. Among them, Berberine, Sanguinarine and Cheleritrine were identified as the most efficient stabilizers for G-quadruplex structures. Their interaction with various nucleic acid conformations was examined in detail in terms of affinity constant and mode of binding by NMR studies, spectroscopic (fluorometric and CD) and ITC titrations. In particular, we focussed our attention on the role of DNA sequence and structure on binding geometry and affinity. Biophysical data were then related to the cytotoxic response of each derivative. From these data we could asses the potential of the tested ligands as G-quadruplex binders (and prospective drug response) at physiological conditions.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2674.
Abstract 268: Regulation and function of ERBB3 signaling pathway in clear cell sarcoma
Authors: Zhang Yixiang , Davis Ian J. , Remillard Stephen P. , Demetri George D. , Fisher David E. , Wagner Andrew J.
Published: February 2011

Clear Cell Sarcoma (CCS), a soft tissue malignancy of tendons and aponeuroses in children and young adults, is notoriously resistant to radiation and chemotherapy, and new approaches to treatment are needed. We recently demonstrated the involvement of the MET receptor tyrosine kinase (RTK) in regulation of the growth, migration, and invasion of CCS cells. However, pharmacologic agents targeting the HGF:MET axis could neither completely inhibit cell growth nor significantly induce apoptosis. To determine whether other RTKs might cooperate with MET in control of survival and proliferation of CCS cells, we used phospho-RTK arrays to assess the activation status of RTKs in three CCS cell lines (CCS292, DTC1, SU-CCS-1). We found that in addition to MET, ERBB3 was strongly activated in CCS. Western blot analysis confirmed constitutive activation of ERBB3 in CCS292 and DTC-1 cell lines and expression in all three lines. Since ERBB3 lacks intrinsic kinase activity, we searched for potential heterodimerization partners. Interestingly, we found that the activation of ERBB3 in different CCS cell lines relied on different partners: ERBB2 as a pivotal partner in CCS292, and MET as a pivotal partner in DTC-1. Moreover, we explored the possibility of a linkage between the CCS pathognomonic EWS-ATF1 fusion product and ERBB3 activation. We found that EWS-ATF1 knockdown resulted in both decreased expression of the ERBB3 ligand Neuregulin 1 and less ERBB3 phosphorylation in CCS292 cells, but had no effects on ERBB3 phosphorylation in DTC-1 cells. To explore the biological function of ERBB3, we applied siRNA or small molecule inhibitors of RTKs to CCS cell lines and determined the biological consequences by cell viability, cell cycle and apoptosis assays; these studies show that ERBB3 in conjunction with MET played an important regulatory role in the proliferation and survival of CCS cells. These data suggest that combined inhibition of the MET and EGFR signaling pathways may be a rationally designed strategy for treatment of patients with advanced CCS.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 268.
Abstract 2682: Integration of multiple prognostic factors into the TNM staging system using a new algorithm that censors patients
Authors: Henson Donald , Chen Dechang , Schwartz Arnold , Hart Alexandra , Pham Ly , Hsiao Joyce , Cheng Xiuzhen
Published: February 2011

Objective: To integrate new and baseline multiple prognostic factors into the TNM (Tumor, Lymph Node, Metastasis) cancer patient staging system using a new cluster algorithm that is able to censor patients.

Methods: Records of women with invasive breast cancer from 1990-2000 were obtained from NCI's Surveillance, Epidemiology, and End Results (SEER) Program. The dataset contained 140,714 patients. Cancer specific survival rates for 60 and 120 months and hazard rates were calculated by the Kaplan-Meier method for all combinations tumor size, lymph node status, histological grade, and estrogen receptor status. The algorithm stratified (clustered) patients according to survival based on prognostic factors. The algorithm uses partitioning and hierarchical categorization. The partitioning step involves repeated use of the algorithm Partition Around Mediods to partition combinations in terms of their survival differences. Survival rates were compared by the logrank test.

Results: From the 140,714 patients, survival and hazard rates were calculated for each combination of the 4 prognostic factors using survival rates for partitioning. Each combination formed a cluster, 96 with 4 factors. In all cases, there was a relation between the prognostic factors and the outcome. The histological grade, tumor size, number of positive lymph nodes, estrogen receptor status all had an effect on survival, which is recognized from clinical experience. Any number of additional factors can be included.

Conclusions: The clinical application of this new clustering algorithm is practical and can be applied to host and tumor factors. The algorithm calculated survival and hazard for all combinations of 4 major prognostic factors for breast cancer. This is the first cluster algorithm that is able to censor patients and overcome the limitations of the TNM bin model.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2682.
Abstract 2686: Analysis of cardiac markers on patients receiving 5-fluorouracil, epirubicin, cyclophosphamide with concurrent celecoxib (FEC-C) neoadjuvant therapy for locally advanced breast cancer
Authors: Yip Adrian Y.S , Loo Wings T. , Chow Louis W.C.
Published: February 2011

INTRODUCTION/PURPOSE: Anthracycline is widely used and studied in neoadjuvant setting for treatment of locally advanced breast cancer (LABC) for many years. Addition of Cyclooxygenase-2 (COX-2) inhibitors might potentiate the anti-cancer effect of chemotherapy and yet, in consideration of its possible cardiotoxicity, many studies were halted. This sub-study is to evaluate the change in serums level of cardiac troponin I (cTnI), N-Terminal Pro B-Type Natriuretic Peptide (Nt-proBNP) and lactate dehydrogenase (LDH) in LABC patients treated with FEC-C.

METHODS: A study group of 34 patients, who received three cycles of neoadjuvant FEC every 3 weeks with concurrent oral celecoxib (F: 500mg/m2; E: 75mg/m2; C: 500mg/m2; Celecoxib: 400mg bid), were included in the cardiac marker analyses. Marker levels of cTnI, Nt-proBNP and LDH in serum samples before treatment and after each cycle of therapy were studied.

RESULTS: Patients tolerated well with this regimen. Neither life-threatening toxicity nor clinical symptom of cardiac damage was observed. Across the three time-points of assessments, the mean cTnI did not exceed the upper limit of normal of 0.2 ng/ml, albeit subtle fluctuation in some patients most likely due to anthracycline-based chemotherapy. After 3 cycles of FEC, the mean cTnI was measured 0.06 ng/ml. Nt-proBNP markers did not change significantly during chemotherapy and the means were less than 250 fmol/ml. Serum LDH, a less specific marker, increased from baseline after 3 cycles of FEC-C insignificantly (p = 0.181) while its changes across treatments were within the normal range of 313 – 618 U/L.

CONLCUSIONS: Neoadjuvant FEC-C therapy is an active and well tolerated regimen. The short-term use of anthracycline-based chemotherapy with COX-2 inhibitor for LABC before operation incurred some changes on cardiac markers. The change however did not outrange the normal values and indicate any cardiac damage.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2686.
Abstract 2707: Impact of accuracy in O6-methylguanine-DNA methyltransferase methylation assays for temozolomide efficacy on glioblastoma
Authors: Nagane Motoo , Kobayashi Keiichi , Shimizu Saki , Shiokawa Yoshiaki , Waha Andreas
Published: February 2011

Background: O6-methylguanine-DNA methyltransferase (MGMT) is implicated in resistance to temozolomide (TMZ). MGMT status has been shown to correlate with survival of patients with glioblastoma (GBM). We evaluated the relationship between promoter methylation status and protein expression of the MGMT gene in patients with GBM treated with TMZ, and also analyzed their prognostic value regarding response to TMZ and survival.

Methods: We analyzed 47 GBM tissues from 43 patients treated with TMZ from September 2003 to January 2009. Among them, 22 patients with recurrent GBM treated with standard TMZ single therapy were subjected to survival analyses. TMZ was given daily orally 75mg/m2 during radiotherapy, or as standard 5/28-day regimen. MGMT protein expression was quantified by Western blotting, and promoter methylation status was determined by both methylation-specific PCR (MSP) and quantitative pyrosequencing.

Results: MGMT promoter methylation was detected in 19/47 cases (40.4%) by MSP, 16/47 (34%) by pyrosequencing, and was significantly correlated with each other (p<0.001). The methylation status correlated significantly with MGMT protein expression as well. Upon TMZ treatment for recurrent GBM, patients with both methylated MGMT promoter by MSP and low MGMT protein expression had a significantly improved progression-free survival (PFS) and overall survival (OS), whereas methylation status by pyrosequencing data did not. MGMT status was the only significant prognostic factor for PFS and OS.

Conclusions: The three MGMT assays revealed similar methylation/expression patterns and were suggested to be important prognostic factors for patients treated with TMZ. Whether precise quantification of the methylation status provides any clinically relevant information on the treatment strategy for GBM needs to be further investigated.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2707.
Abstract 2708: E-cadherin expression might be a predictive marker for chemosensitivity in triple-negative breast cancer
Authors: Shinichiro Kashiwagi , Yashiro Masakazu , Takashima Tsutomu , Noda Satoru , Kawajiri Hidemi , Matsuoka Junko , Fuyuhiro Yuhiko , Kato Yukihiro , Doi Yosuke , Kubo Naoshi , Tanaka Hiroaki , Muguruma Kazuya , Inoue Toru , Sawada Tetsuji , Onoda Naoyoshi , Nakata Bunzo , Ohira Masaichi , Ishikawa Tetsuro , Hirakawa Kosei
Published: February 2011

Introduction: Triple-negative breast cancer (TNBC), a subtype of breast tumor with ER negative, PR negative, and HER2 negative, shows a poor prognosis because of a frequent recurrence. Chemotherapy is important for the treatment of recurrent TNBC, however no reliable parameter has been identified for chemo-sensitivity in TNBC. Although E-cadherin is one of markers for chemo-sensitivity in several types of carcinomas, not much of the correlation between E-cadherin expression and chemo-sensitivity is known in TNBC. The aim of this study was to evaluate the significance of E-cadherin in TNBC.

Material and Methods: The subjects of this study were 574 patients with primary infiltrating breast ductal cancer. Adjuvant therapy was performed according to the guidelines of breast cancer by NCCN. ER and PR status were assessed by immunohistochemistry. HER2 status was assessed by either immunohistochemistry or fluorescent in situ hybridization. E-cadherin expression was immunohistochemically analyzed by ABC method. E-cadherin expression was semi-quantitatively analyzed according to the percentage of cells showing membrane positivity: 0-10%; 0, 10-30%; 1+, 30-70%; 2+, >70%; 3+. E-cadherin expression was considered positive when scores were ≥2+.

Results: Among the 574 breast cancer cases, 123 (21.4%) revealed a triple-negative phenotype. Reduced levels of E-cadherin were observed in 238 (41.5%) of the 574 breast cancer cases. The cases with E-cadherin loss was frequent (90 of 123 cases) in TNBC. Eighty-nine cases of 123 TNBC cases were performed chemotherapy. In 89 TNBC cases with chemotherapy, the prognosis of E-cadherin-negative patients is significantly poor (p<0.01), in comparison with that of E-cadherin-positive patients, while a multiple analysis demonstrated that reduction of E-cadherin expression was not an independent prognostic factor. In contrast, no significant difference of prognosis between E-cadherin positive patients and negative patients was found in 34 TNBC cases without chemotherapy. Conclusion: E-cadherin might be a useful predictive marker for chemo-sensitivity in TNBC.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2708.
Abstract 271: Heregulin internalization to the nucleus is mediated via binding to nucleolin
Authors: Yang Lin , Lupu Ruth
Published: February 2011

Heregulin internalization to the nucleus is mediated via binding to Nucleolin

Lin Yang, and Ruth Lupu. Department of Laboratory Medicine and Pathology, Mayo Clinic Foundation, Rochester, Minnesota 55902

Heregulin (HRG) is known as a soluble secreted growth factor of EGF-like family, which binds and activates HER3 and HER4 and transactivates HER2 and HER1 receptors. It has been shown that HRG translocates to the nucleus in triple negative breast cancer cells that express high level of HRG. The mechanism by which HRG translocates to the nucleus is still unknown. We have recently uncovered that Nucleolin binds to Heregulin and allows HRG to translocate to the nucleus. Mass spectrometry analysis revealed that multifunctional protein Nucleolin is a major HRG-associated protein. Using co-immunoprecipitation we confirmed HRG interacts with Nucleolin in both endogenous and ectopic levels. Then, we made deleted mutants of HRG to map the Nucleolin binding domain on HRG and we found that Nucleolin binds to HRG on its N-terminus which contains a putative nuclear localization signal (NLS). Remarkably, in these cells we found a striking peri-nuclear accumulation when Nucleolin was knocked down. These results show for the first time that HRG translocate to the nucleus mediated by Nucleolin binding in breast cancer cells. Importantly, the nuclear function of HRG remains as a positive regulator of chemosensitization.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 271.
Abstract 2712: Heterogeneous nuclear ribonucleoprotein H1 confers transcription and transactivation of androgen receptor: Implications for prostate cancer progression in African American men
Authors: Yang Yijun , Jia Dingwu , Davis Rodney , Moparty Krishnarao , Thomas Raju , Moroz Krzysztof , Agrawal Krishna C. , Abdel-Mageed Asim B.
Published: February 2011

Caucasian American (CA) and other ethnic minority groups. The causes of this ethnic disparity in clinical manifestation and outcome of the disease are not well understood. Here we identified, by employing a combined approach of laser capture microdissected (LCM), suppressive subtractive hybridization (SSH), and custom race-based CaP cDNA microarray on fresh specimens, selective expression of heterogeneous nuclear ribonucleoprotein H1 (hnRNPH1) in prostate tumor cells of AA men in comparison to CA men. An ethnicity-based tissue microarray (TMA) analysis revealed selective nuclear accumulation of hnRNPH1 in tumor cells compared to adjacent normal epithelium and benign prostatic hyperplasia (BPH). We also show that hnRNPH1 up-regulates transcription, physically interact with, and confers hormone-dependent (HD) and independent (HI) transactivation of androgen receptor (AR) in CaP cells. Further, our reporter, ChIP, and EMSA analyses demonstrate hnRNPH1 binds to androgen response elements (AREs) on promoter and enhancer element of PSA gene and the ligand binding domain-encoding exons D, E and H of the AR gene, suggesting it acts as a coactivator of AR in CaP cells. Interestingly, siRNA silencing of hnRNPH1caused growth arrest and enhanced cytotoxicty of Bicalutamide in AR-expressing CaP cells. These findings support a model in which hnRNP H1 is an exclusive auxiliary factor for AR to elicit androgen-specific transcriptional regulation of androgen-regulated genes and drug resistance. Given heterogeneity of CaP and that AR is implicated in androgen independent progression of CaP, the results demonstrate a previously uncharacterized mechanism for AR-hnRNPH1 axis in disease progression and hormone refractory via enhancing HD and HI mediated transcription and transactivation of AR in a subset of prostate tumor cells in AA men. The results not only reveal racial differences in the biology of CaP, but also provide, for the first time, a new frontier for the development of diagnostic, preventive, and/or targeted therapeutic strategies to circumvent disease progression in AA men.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2712.
Abstract 2714: Colorectal Cancer in young (<50 years old) African Americans, Could race be a risk factor? A 20 years experience in an inner city teaching hospital
Authors: Ashktorab Hassan , Mohammed Roshila , Nouraie Mehdi , Brim Hassan , Lee Edward , Ghadyari Firoozeh , Moon Tara , Yepuri Aparna D. , Zahaf Marwah , Smoot Duane T.
Published: February 2011

BACKGROUND: Colorectal cancer (CRC) is the third most common cancer, and survival in African Americans (AAs) is worse than Caucasians. Some studies suggest that the incidence of CRC is higher in AA patients below the age of 50 when compared to Caucasians. This study aims to confirm the higher prevalence of CRC in an AA population less than 50, and its implications to the screening guidelines.

METHOD: In a retrospective study demographic data, indication and outcome of colonoscopy, and biopsy data were collected at Howard University Hospital (HUH) over a period of 21 years (1989-2008). All of the study patients were (AA), and cases were classified either symptomatic average risk (91%); or high risk (family history, IBD) (9%). Distribution of variables was studied by median (inter-quartile range) or number (%).

RESULTS: Seventy five CRC cases younger than 50 years old were recorded from 1989 to 2008 at HUH. Median age (inter-quartile range) of these patients were 43 (40-46) years and 35 (47%) were female. Among them 55 (73%) were adenocarcinoma and 43 (57%) were located at left colon. In the same period a total of 671 CRC was recorded in HUH. We compared this data with 4591 CRC cases who were registered at District of Colombia (DC) from 1996 to 2007. While in HUH 11% of all CRC cases were under 50, this ratio for DC area was 9% (P=0.1). Among HUH patients 4%, 16% and 80% were 20-29, 30-39 and 40-49 years old, respectively. In DC area these ratios were 3%, 26% and 70% (P = 0.2). Among HUH tumors with available data 49%, 40%, 11% were local, regional, distant and unknown extension, while these proportions in DC area were 40%, 37%, 23% (P=0.018), respectively.

CONCLUSION: Our data showed a high burden of colorectal CRC in young AAs (<50). CRC rate of 80% (60/75) was seen for the age group of 40-49, which indicates cancer in AAs may starts at younger age than predicted (<45). The American College of Gastroenterology recommends to start screening of AAs at age of 45, but this may not cover many high risk people who are younger than 45. Further study is needed on AAs to confirm these findings.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2714.
Abstract 2731: Serum prostate health index and biopsy tissue DNA content at the time of diagnosis predicts the need for treatment in men enrolled in an active surveillance program
Authors: Isharwal Sumit , Makarov Danil , Sokoll Lori J. , Landis Patricia , Marlow Cameron , Epstein Jonathan I. , Partin Alan W. , Carter H. Ballentine , Veltri Robert W.
Published: February 2011

Introduction and Objective: We assessed a novel application of the Prostate Health Index [Phi = (proPSA / free PSA) × (square root of PSA)] developed by Beckman-Coulter Inc. and DNA content measurements in benign-adjacent and cancer tissue areas to predict which patients would eventually require treatment for prostate cancer (PCa) in an active surveillance (AS) cohort.

Methods: We identified 71 men at the Johns Hopkins Hospital AS program which had banked serum from the time of diagnosis available for the study. 39 developed an unfavorable biopsy (Gleason score >6, Gleason pattern 4/5, >2 cores positive for cancer, >50% of any core involved with cancer), while 32 have maintained favorable biopsies (median follow-up: 3.7 years). Serum total PSA, free PSA and [−2] proPSA were measured by the Beckman Coulter immunoassay. DNA content measurements of Feulgen-stained biopsy sections were performed with the AutoCyteTM imaging system. Cox proportional hazard regression and Kaplan-Meier plots were used to identify significant prognosticators for unfavorable biopsy conversion-free survival.

Results: The ratio of Phi in serum was significantly higher (37.23 ± 15.76 vs. 30.60 ± 12.70 p=0.03) in men ultimately developing unfavorable biopsies. Serum Phi [HR(95%CI): 2.39 (1.26-4.52), p=0.007], BA excess of optical density (OD) [HR (95%CI): 2.58 (1.17-5.68), p=0.019] and CA standard deviation of OD [HR (95%CI): 5.36 (1.89-15.24), p=0.002] were significant predictors of an unfavorable biopsy conversion in both Kaplan-Meier and Cox regression analysis. Patients with Phi >34.2 and CA standard deviation of OD >4.0 showed the highest risk for unfavorable biopsy conversion (p<0.0001).

Conclusions: Measurement of the serum Phi and tissue DNA content at the time of diagnosis are able to predict which men enrolled in an AS cohort will ultimately require treatment for PCa.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2731.
Abstract 2734: Tumor-associated antigen c-terminal binding protein-2 is overexpressed in epithelial ovarian tumors
Authors: Barroilhet Lisa M. , Yang Junzheng , Welch William R. , Berkowitz Ross S. , Ng Shu-Wing
Published: February 2011

OBJECTIVES: Investigation of the expression pattern and functional roles of tumor antigen CtBP-2 in ovarian cancer. BACKGROUND: Tumor-associated antigens may have mechanistic function in cancer development and serum antibodies that target the tumor-associated antigens may have value in early detection. Antibodies to C-terminal binding protein 2 (CtBP-2), a component of the Wnt signaling pathway and a transcriptional corepressor via interaction with histone deacetylases (HDACs), were identified in patient serum using an innovative reverse capture antibody array method. We investigated the expression and function of CtBP-2 in human ovarian cancer tissue and ovarian cancer cell lines. METHODS: CtBP-2 expression was studied in 105 paraffin-embedded ovarian tumors by standard immunohistochemistry (IHC). ANOVA was used to compare the mean IHC staining scores (area stained x intensity) between healthy and tumor samples. Functional assays were performed with human ovarian cancer cell lines SKOV3 and MCAS that stably integrated a CtBP2-targeting short-hairpin RNA (shRNA) construct via a Lentivirus vector. Protein expression was examined by western blotting. Cell proliferation in culture was evaluated by cell counting. Cell adhesion assays were performed using a CytoMatrix Screen kit from Millipore. Cell migration assays were performed using a Boyden chamber-based cell migration assay. B-catenin activity was measured using a TOPFLASH luciferase reporter assay. Cellular sensitivity to trichostatin A, a HDAC inhibitor, was measured using MTT assay. RESULTS: 83% of ovarian epithelial tumors stained positive with a mean score of 4.77 (borderline tumors) and 5.49 (invasive tumors) and showed a significant difference (p-value 50% and showed reduced proliferation rates. The knock-down cell lines also showed 40-80% reduction in adhesion to extracellular matrix proteins collagen I and collagen IV, 50-70% reduction in migration, suppressed B-catenin activity and enhanced sensitivity to trichostatin A. CONCLUSIONS: CtBP-2 is overexpressed in ovarian epithelial tumors and cancer cell lines. Ovarian cancer cell lines with suppressed CtBP-2 expression show a reduction in proliferation rate, cell adhesion and cell migration. The phenotype may be related to suppressed B-catenin activity. The knockdown cell lines are also more sensitive to HDAC inhibitor trichostatin A, suggesting that the expression of CtBP-2 might modulate cellular response to HDAC inhibitor in the clinical setting.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2734.
Abstract 2743: Accelerating the exploration of novel gene fusion events in prostate cancer
Authors: Pflueger Dorothee , Terry Stephane , Sboner Andrea , Habegger Lukas , Esgueva Raquel , Svensson Maria A. , Lin Pei-Chun , Kitabayashi Naoki , Moss Benjamin J. , Tewari Ashutosh K. , Chee Mark S. , Demichelis Francesca , Gerstein Mark B. , Rubin Mark A.
Published: February 2011

Gene fusions are regarded as cancer defining and often proven causative for cancer development. Up to 50% of prostate cancers harbor recurrent gene fusions, most often the TMPRSS2-ERG fusion. Other ETS gene fusions have been described involving ETV1, ETV4, and ETV5. The remaining prostate cancers are considered gene fusion negative based on fluorescence in-situ hybridization (FISH) or RT-PCR for known fusion specific transcripts. Paired-end RNA-sequencing is a novel approach to systematically interrogate for fusion transcripts in a global and un-biased manner. Herein, we exploit FusionSeq, a computational tool specifically developed to nominate chimeric transcripts from paired-end RNA-seq data, with the goal of identifying new gene fusions. Using FusionSeq we identified the androgen-induced genes FKBP5 and KLK2 as two novel 5′ fusion partners for the ETS genes ERG and ETV1, respectively. General transcriptional chimerism (e.g. read-through transcripts) without evidence of underlying genomic rearrangements is not restricted to prostate cancer but also occurs in the patient's matched benign prostate tissue, providing evidence for an extended complexity of the cellular transcriptome and supporting the notion that a gene's definition might have to be considered flexible. Finally, we report the identification and the validation of two novel gene fusions: i) the tumor suppressor and cell cycle regulator CDKN1A (p21WAF, CIP1) is fused to CD9; besides down-regulating p21 gene expression, the CDKN1A-CD9 fusion also alters the CD9 protein. ii) by fusing IKBKB (IKK2, IκB kinase beta subunit) to TNPO1 (transportin 1), IKBKB gene expression increases over other prostate cancers, suggesting a pronounced activation of the NFκB complex. Our results show that a small subset of prostate cancers may harbor private gene fusions involving tumor suppressors and regulators of pathways implicated in cancer development.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2743.