bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 5317: Non-invasive dynamic bioluminescence imaging of tumor functional vascular changes during antiangiogenic therapy in conscious mice
Authors: Schnell Christian R. , Orsini Vanessa , Barbé Stéphanie , Arnal Samuel , Cozens Robert
Published: June 2012

Bioluminescence imaging has been used for several years in oncology research to quantify tumor growth and metastatic spread rather than functional physiological effects.

Two recent publications have highlighted the use of non-invasive dynamic bioluminescence imaging (DBLI) in isofluran anesthetized mice to assess vascular changes in subcutaneous xenografts (1) and orthotopic implanted tumors (2) post-treatment.

We have previously reported that anesthesia impairs bioluminescence signal intensity (3) and may in turn profoundly affect interpretation of compound activity based on BLI (4).

Thus, we decided to investigate DBLI for non-invasive, longitudinal and quantitative monitoring of functional vascular changes (tumor perfusion, blood volume, vascular flow) in conscious mice during antiangiogenic therapy. Subcutaneous xenografts (HCT116 colorectal, U87MG glioblastoma and SJSA-1 osteosarcoma) were treated with a blocking antibody to vascular endothelial growth factor receptor 2 (DC101) and repeatedly examined at bi-weekly intervals.

Our results have clearly demonstrated that in all tested models, tumor growth was significantly inhibited (T/C: 0.33, 0.52 and 0.53 for HCT116, U87MG and SJSA-1, respectively) after treatment with DC101 when compared to control. DBLI analysis revealed an initial increase in vascular flow (Day 2 to 3) followed by a gradual decrease after a 2-wk therapy, suggesting early and long-term effects on functional tumor vasculature. Notably, this pattern was more pronounced in highly vascularized (SJSA-1) when compared with less well vascularized (HCT116) tumors. Lastly, very similar decreased microvessel density (MVD) was noted by histological immuno-fluorescence staining following chronic treatment with DC101 in all three tumor models.

In conclusion, DBLI measurements in conscious tumor bearing mice offer an optimal and reliable approach for non-invasive functional tumor vessel assessment without the confounding effects of anesthesia. It can be foreseen that with future development of more efficient light-emitting enzyme/substrate systems and the improvement of detection devices it will be possible to increase the sensitivity of this technique allowing the measurement of weaker bioluminescence signals and extending spatial resolution.

References:

[1] Zhao et al. FASEB J. 22, 2445-2451 (2008).

[2] Sun et al. Neurosurgery 66, 751-757 (2010).

[3] Schnell et al. AACR meeting (2009), Tumor Biology, Abstract 4006.

[4] Schnell et al. EORTC meeting (2010), Animal models, Abstract 261.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5317. doi:10.1158/1538-7445.AM2011-5317
Abstract 5327: In vivo fluorescence imaging of solid tumor-bisphosphonate interaction
Authors: Papineni Rao V. , Udayakumar Thirupandiyur , Ahmed Mansoor , Pizzonia John , Pollack Alan
Published: June 2012

Bisphosphonates are used for the osteoporosis and in palliative cancer related bone pain management. A role in the cancer cell proliferation and metastases prevention has been proposed. Here, we determined the possibility of utilizing NIR dye conjugated bisphosphonate drug as a potential theragnostic agent. Alendronate was conjugated to water soluble, near-infrared tricarbocyanine, cyclic enamine-functionalized dye, and the imaging probe was used for the purpose. Near-infrared (NIR) fluorescence imaging of both LNCaP cells in cell culture and grown orthotopically in nude mice indicate NIR-bisphosphonate binding. Both in vivo and ex vivo NIRF image analysis of 4 nmol of NIR conjugate delivery show substantial tumor residence time and routine biodistribution to areas of high metabolic bone activity. We present here early evidence of NIR-bisphosphonate analog as a potential diagnostic tool.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5327. doi:10.1158/1538-7445.AM2011-5327
Abstract 5330: Leukemia initiating cells are frequent and oligoclonal in de novo resistant ALL
Authors: Bornhauser Beat , Schmitz Maike , Breithaupt Petra , Scheidegger Nastassja , Mirkowska Paulina , Meissner Barbara , Bonapace Laura , Tchinda Joelle , Cario Gunnar , Schrauder Andre , Stanulla Martin , Schrappe Martin , Jean-Pierre Bourquin
Published: June 2012

Xenotransplantation of primary leukemia cells constitutes an attractive strategy to model disease for translational research, but the consequences of selective pressure on leukemia cells need to be clarified. Here we evaluate the phenotypic and genetic stability of primograft samples that were established by xenotransplantation of ALL cells from a group of patients with very high-risk precursor B-cell ALL, characterized by the persistence of minimal residual disease (VHR-ALL by MRD) after an intensive induction and consolidation therapy. Phenotypic properties remained unchanged, with concordant immunophenotypes in 9-10/10 leukemia-associated markers after up to 5 passages in Nod/scidIL2Rgammanull (NSG) mice and with stable drug response profiles in vitro on bone marrow stroma co-cultures. In 4/6 cases, 100 unsorted ALL cells were sufficient to reconstitute the leukemia. From up to 5 recurrent copy number abnormalities (CNA) detected in diagnostic samples, most were maintained in primografts. Changes in CNAs upon transplantation in NSG mice were few with 0-2 new lesions per case, mostly occurring during the first xenotransplantation. At the single cell level, the pattern of deletions in the CDKN2A/B locus revealed distinct subsets of ALL cells, which could reproducibly be tracked in primografts. These results provide unequivocal data for the existence of clonally closely related but distinct subsets of leukemia initiating cells in ALL, which has important implications for the use of this model for translational research.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5330. doi:10.1158/1538-7445.AM2011-5330
Abstract 5344: Genome-wide identification of PAX3-FKHR binding sites in rhabdomyosarcoma reveals candidate target genes important for development and cancer
Authors: Cao Liang , Yu Yunkai , Bilke Sven , Walker Robert L. , Azorsa David O. , Helman Lee J. , Meltzer Paul S.
Published: June 2012

The paired box transcription factor (PAX) family consists of 9 highly related members with critical roles in organogenesis and tissue specification during development, including skeletal muscle, pancreas, central nervous system, kidney, and immune system. In various cell model systems, PAX genes have been implicated in the maintenance of the multipotent state, the initiation of differentiation programs, cell migration, proliferation and survival. Mutations and gene rearrangement of PAX genes are frequently associated with human diseases and cancers. In particular, PAX3 and PAX7 are required during early embryogenesis for the development of the neural-crest and skeletal muscle, and gene rearrangements with FKHR are frequently implicated with rhabdomyosarcoma (RMS). The PAX3-FKHR fusion protein is present in the majority of alveolar rhabdomyosarcoma (ARMS) associated with increased aggressiveness and poor prognosis. To better understand the molecular pathogenesis of PAX3-FKHR, we carried out the first and unbiased genome-wide identification of PAX3-FKHR binding sites and associated target genes in ARMS, with a novel monoclonal antibody specific for the fusion protein. The data shows that PAX3-FKHR binds to the same sites as PAX3 at both MYF5 and MYOD enhancers. The genome-wide analysis reveals that the PAX3-FKHR sites are: 1) mostly distal to transcription start sites; 2) conserved; 3) enriched for PAX3 motifs; and 4) strongly associated with genes over-expressed in PAX3-FKHR positive RMS cells and tumors. There is little evidence in our dataset for PAX3-FKHR binding at the promoters. The genome-wide analysis further illustrates a strong association between PAX3 and E-box motifs in these binding sites, suggestive of a common co-regulation for many target genes. We further provide the first direct evidence that FGFR4 and IGF1R are the targets for PAX3-FKHR. The study is the first genome-wide analysis of direct targets for a PAX protein. The map of PAX3-FKHR binding sites provides the frame work for the understanding of PAX3-FKHR pathogenic roles and molecular targets to allow a systematic evaluation of agents against this aggressive RMS.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5344. doi:10.1158/1538-7445.AM2011-5344
Abstract 5345: A novel small molecule, XZH-5 inhibits constitutive and interleukin-6-induced STAT3 phosphorylation in human rhabdomyosarcoma cells
Authors: Liu Aiguo , Liu Yan , Xu Zhenghu , Yu Wenying , Wang Hong , Li Chenglong , Lin Jiayuh
Published: June 2012

Rhabdomyosarcoma is the most common soft tissue sarcoma of childhood. Despite the fact the improved treatment for Rhabdomyosarcoma has resulted in a remarkable increase of overall survival, the children with metastatic Rhabdomyosarcoma still have only a 3-year failure-free survival rate of less than 30%. Constitutive activation of Signal Transducers and Activators of Transcription 3 (STAT3) signaling is frequently detected in most types of cancer including human RMS. STAT3 is considered to be an oncogene due to its ability to promote malignancy in mice. Given the oncogenic functions of STAT3 and the promise of inhibiting it, directly targeting STAT3 signaling represents a potential therapeutic approach to treating Rhabdomyosarcoma. Using structure-based drug design, we developed a novel small molecule, named XZH-5. In this study, we characterized the inhibitory effects of XZH-5 on STAT3 phosphorylation in four Rhabdomyosarcoma cell lines. XZH-5 competes with/inhibits the STAT3-SH2 dimerization through phosphorylated Tyr705 in all four Rhabdomyosarcoma cell lines. We also demonstrated a similar inhibition of STAT3 phosphorylation and induction of apoptosis by a previously known small molecular STAT3 inhibitor Stattic in Rhabdomyosarcoma cells. These results supporting Rhabdomyosarcoma cell lines are sensitive to STAT3 inhibition. In addition, XZH-5 inhibited STAT3 DNA binding activity and the expression of STAT3 downstream genes including Bcl-2, Bcl-xl, Cyclin D1 and Survivin. The inhibition of STAT3 in Rhabdomyosarcoma cells resulted in the induction of apoptosis, reduction of colony forming ability, and inhibition of cell migration. Furthermore, XZH-5 inhibited IL-6-induced STAT3 phosphorylation and STAT3 nuclear translocation. In contrast, it had no effect on IFN-γ-induced STAT1 phosphorylation, indicating the more selective effects on STAT3. These results demonstrated that Rhabdomyosarcoma cells are sensitive to STAT3 inhibition and STAT3 is a therapeutic target. Our results also suggested that XZH-5 may serve as a potential therapeutic agent for targeting STAT3 for Rhabdomyosarcoma treatments.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5345. doi:10.1158/1538-7445.AM2011-5345
Abstract 5354: Characterisation of the cell line HC-AFW1 derived from a paediatric hepatocellular carcinoma
Authors: Armeanu-Ebinger Sorin , Wenz Julia , Seitz Guido , Leuschner Ivo , Handgretinger Rupert , Fuchs Jörg , Warmann Steven W.
Published: June 2012

Paediatric hepatocellular carcinoma (HCC) has an incidence of 1.5 cases per million children and is linked to viral hepatitis in endemic regions. In Europe childhood HCC mostly arises in otherwise healthy liver and has an unknown ethiology. Current treatment results of HCC are dissatisfactory due to advanced disease at diagnosis and lacking response to chemotherapy. To improve the research of childhood HCC and to address specific therapeutic approaches a preclinical model for childhood HCC is needed. So far, there has been one existing cell line, HepG2, which has lately been discussed controversially as being hepatoblastoma. We established a cell line HC-AFW1 from the tumor of a 5 year old boy. The original tumor histology was characteristic as transitional liver cell tumor including hepatoblastoma and HCC morphology. These histological findings were confirmed through several reference pathology laboratories worldwide. The cell line HC-AFW1 was established by xenotransplantation of original tumor into immuno-deficient mice and re-culturing in vitro. The cell line is in sable culture now for over 8 months with a doubling time of 40 h. Cultured cells present epithelial characteristics and express hepatoma proteins like AFP, glypican 3, E-cadherin, CD10, CD326, HepPar1, Vimentin and Desmin. Catenin beta shows a deletion of 49 amino acids in the exon 3 involving the phosphorylation sites of GSK3 and was detected in cell nuclei. Cytogenetic analysis revealed large anomalies in the chromosomal map. This involves chromosomal aberrations found in hepatoblastoma as well as in adult HCC. Several alterations of gene copy numbers were detected by genome wide SNP array. Among different tested drugs cisplatin and irinotecan showed an effective inhibition of tumor cell growth in an MTT assay at concentration below 5 µg/ml. Transplantation of HC-AFW1 cells into NOD/SCID mice resulted in fast growing dedifferentiated tumors with high levels of serum AFP. This xenotransplants as well as stable cultured cells solely consist of HCC components suggesting a selection of HCC and degeneration of formally hepatoblastoma tumor parts. Therefore, HC-AFW1 is the first paediatric HCC-derived cell line and represents a valuable tool to investigate the biology and therapeutic strategies in childhood HCC.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5354. doi:10.1158/1538-7445.AM2011-5354
Abstract 536: A hypoxia-activated protein switch as a potential anticancer therapeutic
Authors: Wright Chapman M. , Ostermeier Marc , Eshleman James R.
Published: June 2012

We have engineered yeast cytosine deaminase (CD) to be activated by the tumor marker, hypoxia-inducible factor 1-alpha (HIF-1a) – turning on its ability to convert 5-fluorcytosine (5FC) into the chemotheraeutic drug 5-fluoruracil (5FU). HIF-1a is overexpressed in many types of cancer but is virtually undetectable in normal tissue due to rapid degradation. We sought a “tumor-sensing” protein whose prodrug converting activity is activated in the presence of HIF-1a. Such a protein would have advantages over therapeutic treatments such as gene-directed enzyme prodrug therapy (GDEPT). Our approach would circumvent the need for specific delivery of the “suicide” gene, which is a requirement in GDEPT, since the selectivity occurs at the protein level and not the gene delivery level. To create our desired protein, we constructed a library of fusion proteins between CD and the CH1 domain of p300 – a domain known to interact with HIF-1a. This library was subjected to a two-tiered genetic selection in E. coli designed to identify genes that conferred increased sensitivity to 5FC when HIF-1a was co-expressed. We identified a library member (HIF-1a activated protein switch 59, “Haps59”), which conferred to E. coli sensitivity to 5FC equivalent to wildtype CD but only in the presence of co-expressed HIF-1a. In the absence of HIF-1a, Haps59 did not confer any sensitivity to 5FC. We created a stable cell line of RKO expressing Haps59 to determine its ability to sensitize them to 5FC. RKO is a colorectal cancer cell line known to accumulate high levels of HIF-1a in hypoxic conditions. RKO cells stably expressing Haps59 in hypoxia were 10-fold more sensitive to 5FC than the same cells in normoxia. This sensitivity was shown to be a result of the presence of 5FC, Haps59, and HIF-1a in RKO cells, and the removal of either of these components resulted in normal cell growth. Further, we demonstrated the direct intracellular interaction of HIF-1a and Haps59. RKO cells expressing Haps59 were used to create xenografts in mouse models. Initial results from experiments using systemically administered 5FC to treat these xenografts will be presented.

Using advanced protein engineering techniques, we have created a protein that confers sensitivity to 5FC in the presence of the tumor-marker, HIF-1a. We believe that the Haps59 gene could have therapeutic potential for the treatment of solid tumors that exhibit elevated HIF-1a levels. Our strategy circumvents a limitation of GDEPT by not requiring selective delivery of the gene to cancer cells.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 536. doi:10.1158/1538-7445.AM2011-536
Abstract 5364: AURA kinases as markers and targets in GIST
Authors: Yen Chueh-Chuan , Chun-Nan Yeh , Hwang Tsann-Long , Chen Miin-Fu , Tzeng Cheng-Hwai , Chao Ta-Chung , Fletcher Jonathan A.
Published: June 2012

Mitotic index has been found to be an important prognostic factor in primary gastrointestinal stromal tumor (GIST). By using gene sets related to cell cycle (Proc Natl Acad Sci U S A. 2008; 22;105(3):955-60), we can stratify a group of patients with advanced GIST (J Clin Oncol 2008;26:4100-4108.) into two risk groups with distinct survival. So it is interesting to explore whether genes involved in regulation of cell cycle could be used as a target in treating GIST. Aurora kinase A (AURKA) and B (AURKB) were two important genes in cell cycle regulation. In the same cohort of patients, expression levels of both AURKA and AURKB were found higher in high risk group patients than those in low risk group. By using MTT assay, GIST882, an imatinib-sensitive GIST cell line, was relatively resistant to both AURKA inhibitor MLN8237 and AURKB inhibitor ZM447439 than GIST 48IM, an imatinib-resistant GIST cell line. MLN8237 could induce significant cell cycle arrest in both GIST cell lines, but apoptosis could only be seen in GIST48IM. On the other hand, after ZM447439 treatment, cell cycle inhibition could only be found in GIST48IM, and none of them had apoptosis. Instead, ZM447439 could induce autophagy in both cell lines. We then used immunohistochemistry (IHC) to examine 76 primary GIST patients. High expression of AURKA but not AURKB was more often seen in non-gastric GIST. In univariate analysis, patients with tumors having strong AURKA IHC staining, as well as large tumor size, high mitotic index and NIH high risk group, had significant lower survival than comparative groups. However, in the multivariate analysis, only high mitotic count and high AURKA expression were independent adverse prognostic factors. In conclusion, cell cycle-related genes could be used in predicting prognosis in advanced GIST, and cell cycle regulated genes such as AURKA and AURKB could be used as treatment targets.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5364. doi:10.1158/1538-7445.AM2011-5364
Abstract 537: Mechanisms by which pantoprazole, a proton pump inhibitor, enhances the activity of doxorubicin in solid tumors
Authors: Tan Qian , Patel Krupa , Lee Carol M. , Zhang Junyan , Joshua Anthony , Koritzinsky Marianne , Wouters Bradly G. , Tannock Ian F.
Published: June 2012

Purpose: Mechanisms of tumour resistance to cytotoxic drugs in solid tumours include limited drug distribution from tumour blood vessels and other effects of the tumour microenvironment. Proton pump inhibitors, such as pantoprazole (PTP), raise endosomal pH and thereby decrease sequestration of basic drugs in acidic compartments. This may allow more drugs to interact with DNA, while decreased net cellular uptake of drug, may allow more drugs to penetrate tissue to distal cells. PTP might also inhibit autophagy, a possible target for anticancer therapy, since endosomes are important intermediaries of this process. Here we describe the effects of PTP on doxorubicin uptake and distribution in cell cultures and solid tumours, and effects to cause growth delay. We have also evaluated the effect of PTP on autophagy of tumour cells.

Methods: Endosomal pH of cells was measured by using Lysosensor and fluorescence spectroscopy. Cytotoxicity was evaluated by a colony-forming assay. Doxorubicin distribution was quantified in MCF-7 xenografts by immunohistochemistry, in relation to blood vessels (recognized by an antibody to CD31), and regions of hypoxia (recognized by an antibody to EF5), with and without pre-treatment with PTP. Anti-tumour effects were evaluated by growth delay following treatment with single or multiple doses of doxorubicin with and without PTP. Effects of PTP on autophagy were evaluated by (i) expression of the LC3II protein by Western blotting and (ii) effects of PTP on prostate cancer PC3 cells transfected with green fluorescent protein) and with LC3 protein (a marker of autophagy) tagged with red fluorescent protein (mRFP-GFP-LC3 cells)

Results: PTP increased endosomal pH and decreased endosomal sequestration of doxorubicin in cultured cells. Pre-treatment with PTP increased the distribution of doxorubicin in solid tumours. PTP alone had no effect on tumour growth but increased the effect of doxorubicin to cause growth delay of human tumour xenografts with no apparent increase in toxicity. PTP showed marked effects to inhibit autophagy in cultured tumour cells in a dose and time dependent manner.

Conclusions/Discussion: PTP increases the effectiveness of doxorubicin against solid tumours and this combination is being investigated in a phase I clinical trial. Potential mechanisms underlying this effect include inhibition of sequestration of doxorubicin in endosomes permitting better drug distribution, and inhibition of autophagy.

Supported by a research grant from the Canadian Institutes of Health Research

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 537. doi:10.1158/1538-7445.AM2011-537
Abstract 5383: Inhibition of MCL-1 in mammary and CNS tumor cells promotes cell death in vitro and in vivo
Authors: Hamed Hossein A. , Mitchell Clint , Dent Paul , Yacoub Adly , Tye Gary , Bareford Mary Danielle
Published: June 2012

Treatment of cells with the BH3 domain/MCL-1 inhibitor obatoclax enhanced the lethality of lapatinib in a synergistic fashion in multiple tumor cell types, including ER+; HER2+; triple negative breast cancer cells and glioblastoma and medulloblastoma cells. Knock out of MCL-1 and BCL-XL enhanced lapatinib toxicity to a similar extent as obatoclax and suppressed the ability of obatoclax to promote lapatinib lethality. Pre-treatment of cells with lapatinib or with obatoclax enhanced basal levels of BAX and BAK activity and further enhanced drug combination toxicity. In vitro, treatment of breast cancer cells with obatoclax and lapatinib enhanced the toxicity of ionizing radiation. In vivo tumor growth data in xenograft and syngeneic model systems of breast cancer confirmed our in vitro findings. Lapatinib and obatoclax interacted to suppress mammary tumor growth in vivo without causing toxicity to multiple normal tissues including brain, heart, lungs, liver or kidneys.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5383. doi:10.1158/1538-7445.AM2011-5383
Abstract 5386: Therapeutic efficacy of RMLV vectors in human and murine glioma models
Authors: Inagaki Akihito , Hiraoka Kei , Logg Christopher R. , Kamijima Shuichi , Ostertag Derek , Perez Omar D. , Gruber Harry E. , Jolly Douglas J. , Robbins Joan M. , Kasahara Noriyuki
Published: June 2012

Unique among replicating viruses being developed as oncolytic agents, replicating murine leukemia virus (RMLV) retroviruses propagate without immediate lysis of host cells and maintain viral persistence through stable integration. Due to its intrinsic inability to infect quiescent post-mitotic cells and susceptibility to innate antiviral defenses that exist in normal cells but are inactivated in many cancers, RMLV vector replication has been shown to be highly tumor-selective. We have previously demonstrated that RMLV vectors are capable of highly efficient replication in tumor cells, and we have found significantly enhanced survival benefit in a variety of cancer models in vivo when RMLV vectors are employed for delivery of prodrug activator genes such as yeast cytosine deaminase (yCD), which mediates the conversion of inactive prodrug 5-fluorocytosine (5FC) to the anti-cancer drug, 5-fluorouracil (5FU). In the present study, we tested a newly developed RMLV vector with modified virus backbone sequences and a codon-optimized yCD gene (Toca511). First, we examined in vitro cytotoxicity using human (U87) and murine (TU-2449) glioma cell lines by MTS assay. The cell viability of Toca511-transduced cells was reduced by >80% after 5 or 8 days of exposure to the prodrug, respectively. Second, we examined the therapeutic efficiency of this newly developed vector in subcutaneous U87 human glioblastoma models and TU2449 syngeneic mouse models. Toca511-mediated prodrug activator therapy strongly inhibited tumor growth in both subcutaneous models. Third, therapeutic efficacy was evaluated, and the minimum effective doses of 5FC prodrug and Toca511 vector determined in an intracranial U87 xenograft model. Systemic administration of 5FC resulted in significant inhibition of bioluminescent signals in mice whose tumors had been infected with Toca511 but not in control mice, associated with significant survival benefit even after injecting only 1×1e3 total vector units (p=0.0015). These data suggest that we have been successful in developing an improved retrovirus vector that shows strong therapeutic efficacy when used for prodrug activator gene therapy in both subcutaneous and intracranial xenograft models of human and/or murine glioma. This vector has now entered Phase I/II clinical trials for glioblastoma. Now, with the use of RMLV vectors such as Toca511, the original promise of retrovirus-mediated gene therapy strategies for cancer may finally be fulfilled.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5386. doi:10.1158/1538-7445.AM2011-5386
Abstract 5387: Prostate-targeted radiosensitization via aptamer-shRNA chimeras
Authors: Ni Xiaohua , Zhang Yonggang , Ribas Judit , Chodhury Wasim H. , Castanares Mark , Zhang Zhewei , Laiho Marikki , DeWeese Theodore L. , Lupold Shawn E.
Published: June 2012

Dose-escalated radiation therapy for localized prostate cancer (PCa) has a clear therapeutic benefit; however, escalated doses may also increase injury to non-cancerous tissues. Radiation-sensitizing agents can improve ionizing radiation (IR) potency, but without targeted delivery these agents will also sensitize surrounding normal tissues. Here we describe the development and application of prostate-targeted RNA interference agents which selectively sensitize PSMA-positive cells to IR. A high throughput siRNA screen identified DNA-PK, MAD2L2, BRCA2, NBN, RAD23B, and RAD54L as candidate DNA-repair pathway targets for prostate cancer radio-sensitization. When candidate shRNAs were conjugated to the PSMA-targeting RNA aptamer, A10-3, they were selectively delivered into PSMA positive prostate cancer cells in the absence of traditional transfection reagents. The shRNA portion was then processed by dicer to the corresponding siRNA. DNA-PK shRNAs, delivered by PSMA-targeting RNA aptamers, selectively reduced DNA-PK in PCa cells, xenografts and human prostate tissues. The mechanism of DNA-PK knock-down was confirmed to be through RNA interference by 5’-RACE assay. In tumor injection models A10-3-DNA-PK-shRNAs, combined with IR, dramatically and specifically enhanced PSMA-positive tumor response to IR. This treatment extended time to reach quadruple tumor volume by approximately 10 weeks when compared to only one week in tumors treated with radiation and control aptamer-shRNAs. A10-3-DNA-PK-shRNA and radiation had no affect on the PSMA negative PC-3 tumors. These studies support aptamer-shRNAs as selective sensitizing agents which may improve the treatment of high-risk localized PCa.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5387. doi:10.1158/1538-7445.AM2011-5387
Abstract 5398: A primer dose followed by low-bolus dose schedule for safe and efficacious bacterial tumor targeting with S. typhimurium A1-R
Authors: Zhao Ming , Zhang Yong , Liu Fang , Hoffman Robert M.
Published: June 2012

We have previously developed a bacterial cancer therapy strategy by targeting viable tumor tissue with Salmonella typhimurium containing two auxotrophic mutations. These auxotrophs grow in viable as well as necrotic areas of tumors. However, the auxotrophy severely restricts growth of these bacteria in normal tissue, making this a relative safe treatment. The S. typhimurium A1-R mutant, which is auxotrophic for leu-arg, and selected for high antitumor virulence, has been shown to be effective as monotherapy against human prostate, breast, pancreatic, and fibrosarcoma tumors that have been orthotopically implanted in nude mice. In the present study, we developed a strategy to maximize efficacy and minimize toxicity for bacterial tumor treatment. A small dose of S. typhimurium A1-R bacteria was first administered to tumor-bearing animals (the primer dose) as pre-treatment followed by a high dose (106 i.v.) 4 hours later. Compared with very high dose bacteria treatment (5 × 106 per mouse), the primer dose strategy had no observable side effects. The very high dose had toxicity in immunocompetent mice. The primer dose may induce cytokines in the mouse necessary for invasion of the tumor by the bacteria allowing a relatively small subsequent dose to be effective and safe.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5398. doi:10.1158/1538-7445.AM2011-5398
Abstract 540: The pro-inflammatory protein S100A9 promotes pancreatic cancer cell growth
Authors: Markowitz Joseph , Mundy Bethany , Jaime-Ramirez Alena C. , Paul Bonnie , Bekaii-Saab Tanios , Carson William E.
Published: June 2012

S100A9 is a pro-inflammatory protein originally found in macrophages which is felt to be important in promoting inflammatory responses and cancer cell growth. The protein is found in cancer cells of gastric, colon, breast cervical and thyroid cancer. Generally, S100A9 is a cytoplasmic, cell surface and secreted protein that promotes cancer cell growth via inflammatory mechanisms and migration of immune cells (e.g. PBMCs) to the cancer microenvironment via non-covalent interactions with glycosaminoglycans on endothelial surfaces. Previously, this protein was reported in the stroma of pancreatic cancers but not in pancreatic cancer cells themselves. This report iilustrates S100A9 up-regulation on the surface of p53 mutant pancreatic cancer cell lines BxPC3 and AsPC1 as determined by immunoblot analysis and flow cytometry. In this study, pentamidine a known inhibitor of S100B, inhibited S100A9 dependent cell growth in BxPC3 cell lines (IC50 = 20.1 +/- 10.3 μM). Pentamidine treated BxPC3 cells (20 μM for 96 hrs) exhibited 30.1% apoptotic cell death as measured by Annexin/PI statining vs less than 3% for control treated cells. Given that S100A9 was found in other cancer models to promote recruitment of pro-infammatory cells (e.g. PBMCs) and subsequent support of cancer cell growth, we studied the effect of pentamidine on PBMC migration. Pentamidine also blocked the migration of PBMC from a metastatic pancreatic cancer patient (67%) to a similar degree as an Anti-s100A9 (68%) Ab or an anti-s100A8/A9 (65%) antibody. S100A8/A9 antibody is known to bind to helix 1 of S100A8 and helix 4 of S100A9, areas of the protein considered important for target interactions. It is likely that pentamidine indiscriminately binds to both the S100A8/A9 heterodimer as well as the homodimer in addition to other S100 proteins. S100A9 levels in BxPC3 cells as detected via Western analysis also increase with 20 μM pentamidine treatment, but not 10 fold as reported in the literature for S100B. As p53 was also shown previously to bind to the S100A9 promoter and S100A9 is not as robustly expressed in mutant p53 cell lines, p53 independent pathways are clearly important for cancer cell survival. This study suggests that S100A9 is up-regulated in pancreatic cancer and that inhibition causes pancreatic cancer cell death.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 540. doi:10.1158/1538-7445.AM2011-540
Abstract 5400: Antiangiogenic gene therapy with VB111 is active in glioblastoma xenografts
Authors: Brenner Andrew J. , Rogge Jessica , Cohen Yael , Breitbart Eyal , Livnat Bangio
Published: June 2012

Introduction: Glioblastoma is a highly vascular tumor with marked endothelial dependence. While anti-angiogenic therapy has shown transient clinical benefit for the treatment of glioblastoma, persistent vascularization is seen with a normalization of blood vessels within the tumor. VB-111 is a dual-action, anti-angiogenic and vascular disrupting agent for cancer treatment aimed specifically at destroying newly formed and existing tumor blood vessels in a safe and efficient manner. VB-111 consists of a replication incompetent adenovirus together with an endothelial angiogenic-specific promoter and a pro-apoptotic Fas chimera transgene.

Methods: Intracranial xenografts were established in nude rats with a luciferase expressing U87 glioma cell line. Rats were treated intravenously with VB-111 at 1011 viral particles or placebo at 21 days post tumor cell implantation. Tumor growth was followed by in vivo bioluminescent imaging and 7T MRI. Rats were sacrificed when moribund or when marked neurologic deficit was observed. Tumors were evaluated by standard histologic methods for vessel density and necrosis.

Results: Untreated rats bearing U87 tumors showed a median survival of 38 days (95% CI 35.1-40.9 days), while animals treated with VB-111 showed a median survival of 48 days (95% CI 42.1-53.9 days). Log rank analysis of survival distributions between these two groups showed a significant difference (p=0.024) in favor of treatment. Luciferase activity, used as a surrogate for tumor volume, began separating between the two groups in week two post treatment and showed a continued trend for reduced activity in the treatment group thereafter. MRI imaging confirmed decreased tumor size in representative animals from the VB-111 group.

Conclusions: VB-111's Dual action therapy is promising for glioblastoma.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5400. doi:10.1158/1538-7445.AM2011-5400
Abstract 5406: Chemosensitization of melanoma by use of the minimalistic nonviral MIDGE expression system for improved TNF-alpha expression in vitro and in vivo
Authors: Walther Wolfgang , Kobelt Dennis , Aumann Jutta , Fichtner Iduna , Schmidt Manuel , Schlag Peter M.
Published: June 2012

Melanomas are often refractory towards chemotherapy. Tumor necrosis factor alpha (TNF-alpha) is known for its strong chemosensitizing potential. However, to exploit this potential, high doses of TNF-alpha are required, which are often associated with severe toxicities limiting the clinical applicability. Alternatively, TNF-alpha can be generated at high level at the tumor site using local application of gene therapy. To achieve this, we employed the nonviral MIDGE vector system for significantly improved TNF-alpha expression. The minimalistic immunologically defined gene expression (MIDGE; Mologen AG, Berlin, Germany) vector system is a linear DNA molecule that is depleted of bacterial backbone, antibiotic resistance sequences and CpG motifs, which significantly reduces its size. In our in vitro experiments using equimolar amounts of luciferase expressing MIDGE vector or plasmid we observed significant up to 13-fold increased MIDGE vector mediated expression in transfected human A375, MeWo and SKMEL-28 melanoma cells. Accordingly the FACScan analysis revealed improved transfection efficiency of MIDGE vectors.

We used the MIDGE vector to efficiently express TNF-alpha in human A375 melanoma cells in vitro. The MIDGE vector generated significantly higher TNF-levels in comparison to plasmid-mediated expression. The in vivo transfer of the TNF-expressing MIDGE vector into A375 melanomas by intratumoral nonviral jet-injection resulted in efficient high level cytokine expression, which was time and vector-dose dependent. Importantly, this high level TNF-expression does not lead to TNF-alpha release into the circulation and does not cause increase in body temperature or losses in body weight. The MIDGE-mediated TNF-alpha expression mediates efficient chemosensitization in the melanoma xenotransplant bearing nude mice by improving the in vivo chemotherapy with vindesine. This is reflected by significant tumor growth inhibition. The study demonstrates the superiority of the MIDGE vector system for nonviral local gene therapy approaches that might be translated into clinical applications.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5406. doi:10.1158/1538-7445.AM2011-5406
Abstract 5407: Tumor penetrating microparticles enhance siRNA delivery and expression in pancreatic cancer
Authors: Wang Jie , Lu Ze , Gu Jing , Cui Mingjian , Dorsten Joy , Wientjes M. Guillaume , Au Jessie L-S.
Published: June 2012

A major challenge for using siRNA as cancer therapeutics is the delivery to solid tumors, due to their unfavorable physicochemical properties (negative charges, large molecular size, and instability). Our laboratory has developed paclitaxel-loaded tumor-penetrating microparticles (TPM) for intraperitoneal therapy of peritoneal tumors (JPET, 327: 673-682, 2008). Embedded in the design of TPM is the tumor priming technology to promote nanomedicine delivery in solid tumors (JPET, 322:80-88, 2007). The goal of this study was to evaluate whether TPM can improve siRNA delivery and expression for treating solid tumors located in the peritoneal cavity. Nanoparticles containing survivin siRNA (siRNA-NP) were developed. Survivin, a major resistance factor, is selectively expressed in tumors and upregulated by various chemotherapeutic agents. The activity of paclitaxel (agent loaded in TPM) and siRNA was investigated in cultured cells using the clonogenic assay and the survivin level determined using western blotting. In vivo activity was evaluated in peritoneal pancreatic HS766T xenograft tumors; the pharmacodynamic endpoints were reduction of proliferation index (measured by Ki67 labeling), induction of apoptosis (measured by caspase 3 expression), prolongation of survival time, and survivin protein level (measured by immunohistochemical staining and quantitative image analysis using NIH ImageJ). The two negative controls were blank nanoparticles (without siRNA) and non-targeting siRNA. In cultured cells, siRNA-NP produced protein knockdown, decreased cell clonogenicity, and enhanced paclitaxel activity. However, siRNA-NP did not produce protein knockdown or antitumor activity in tumors grown in animals, indicating insufficient delivery in vivo. In contrast, when given in combination with TPM, siRNA-NP produced survivin knockdown and enhanced the antitumor activity of TPM. The results indicate that TPM treatment improves the delivery and transfection of siRNA in intraperitoneal tumors in vivo and suggest potential therapeutic utility of coadministered TPM and siRNA-NP combination. Supported in part by research grants R44CA103133 and R43CA134047 from NCI, DHHS.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5407. doi:10.1158/1538-7445.AM2011-5407
Abstract 5425: Potent curcumin analogue FLLL-22, but not natural curcumin, targets the DNA damage pathway for apoptosis in lung and head and neck cancer cells
Authors: Amin A.R.M. Ruhul , Lee Michelle , Rahman Mohammad A. , Fuchs James R. , Chen Zhuo G. , Shin Dong M.
Published: June 2012

Curcumin, 1, 7-bis (4-hydroxy-3-methoxyphenyl)-1, 6-heptadien-3, 5-dione, is the major bioactive compound isolated from the rhizome of Curcuma longa (turmeric). Despite its high margin of safety (no dose-limiting toxicity at doses up to 10 g/day in human) and efficacy against various types of cancers, the potential utility of curcumin as a chemopreventive/chemotherapeutic drug is compromised by its low bioavailability and poor selectivity. To circumvent these problems, more potent and selective curcumin analogues have been introduced. In the current study, we investigated one such synthetic analogue, (1E, 4E)-1, 5-bis (2, 4, 6-trimethoxyphenyl) penta-1, 4-dien-3-one (FLLL-22), against the head and neck cancer cell line Tu212 and lung cancer cell line H460. We conducted an SRB assay to determine IC50 values which showed that FLLL-12 was 24.6-fold and 31.6-fold more potent than natural curcumin against Tu212 and H460 cells, respectively. FLLL-22 also more strongly inhibited colony formation in both cell lines than that of natural curcumin. FLLL-22 at 1 μM was sufficient to completely inhibit colony formation, whereas up to 5 μM of curcumin had only minimal effects on colony formation. FLLL-22 also induced apoptosis more strongly (∼10-fold) than natural curcumin as evidenced by annexin V-PE staining and cleavage of PARP. Interestingly, FLLL-22, but not natural curcumin, activates DNA double strand breaks as evidenced by phosphorylation of H2AX and activation of p53 pathway. Although FLLL-22 strongly phosphorylated H2AX at doses of 3 and 5 μM, no H2AX phosphorylation was observed after curcumin treatment with doses 20 and 30 μM. At these doses, both compounds induced comparable apoptosis. FLLL-22 increased the protein level of p53, its phosphorylation at Ser15 and Ser392, and downstream target p21. A slight increase in p53 expression was observed with 20 μM curcumin, but not with 30 μM. Ablation of p53 by shRNA inhibited FLLL-22-induced p21, suggesting that FLLL-22 activates p53-dependent transcription. We also found that treatment with both FLLL-22 and curcumin inhibited phosphorylation of AKT, S6 and expression of Bcl-2. Taken together, our data strongly suggest that FLLL-22 is a potent curcumin analogue which activates the DNA damage pathway to induce apoptosis and might be a suitable anti-cancer drug for further preclinical and clinical development (supported by U01CA101244, R01CA112643, and P50CA128613 to DMS).

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5425. doi:10.1158/1538-7445.AM2011-5425
Abstract 5433: Analysis of the short-term and long-term in vitro cytotoxic effects of the anticancer drug Ukrain in breast cancer models
Authors: Bozeman Erica , Mohammadi Hamid , Shashidharamurthy Rangaiah , Daniels Danielle , Selvaraj Periasamy
Published: June 2012

Ukrain is a semisynthetic compound derived from the extract of the plant Chelidonium majus L. Studies indicate that this anticancer drug exhibits cytostatic and cytolytic activity against several human cancer cell lines including colon, brain, ovarian, melanoma and lymphoma without adverse harmful side effects on healthy human cells. However, such activity has not been thoroughly investigated in a breast cancer model. In order to assess the in vitro cytotoxicity of Ukrain, we used mouse (4T07 and TUBO) and human (SKBR-3) breast cancer cell lines. 4T07 and TUBO are highly tumorigenic, nonmetastic tumor cell lines derived from spontaneous carcinomas in BALB/cfC3H and BALB-neuT mice, respectively. The TUBO and SKBR-3 cell lines constitutively express the HER-2/neu oncogene, which is overexpressed in 30% of human breast cancer patients. Tumor cells were trypsinized after reaching 90-95% confluency and plated with varying concentrations of Ukrain. Following 24, 48 and 72 hour treatment with Ukrain, cell number and viability was determined using the trypan blue exclusion method. To assess whether the tumor cells retained the capacity for unlimited proliferation, a clonogenic assay was conducted. Cells were seeded out in appropriate dilutions to form colonies within 2-3 weeks. Colonies were fixed and stained with crystal violet (0.5% w/v) and counted by microscopy. Lastly, to determine whether the cytotoxic effects of Ukrain are due to the induction of apoptosis, we carried out intracellular staining for active caspase-3. We observed a dose-dependent and time-dependent inhibition of tumor cell growth. As low as 50 υg/mL of Ukrain led to a significant decrease in tumor cell viability when compared to untreated cells. The clonogenic assay showed the inability of treated tumor cells to form colonies and regain their proliferative capacity whereas the untreated cells formed multiple colonies. We observed a several fold increase in caspase 3 activation of Ukrain treated cells compared to untreated cells confirming apoptosis as the cytotoxic mechanism of action. In conclusion, our data suggest that Ukrain could be effective as an anticancer drug for breast cancer due to its short-term and long-term inhibitory effects on tumor cell viability and proliferation.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5433. doi:10.1158/1538-7445.AM2011-5433