bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 5252: Sequential biphasic changes in claudin1 and claudin4 expression correlate to colorectal cancer progression and liver metastasis
Authors: Georges Rania , Bergmann Frank , Adwan Hassan , Berger Martin R.
Published: June 2012

Terminal progression of colorectal cancer culminates in liver metastasis. To identify genes that are involved in the metastatic phenotype, cDNA microarrays were used to analyze mRNA expression profiles of CC531 rat colon adenocarcinoma cells for changes related to their homing into the liver. Briefly, CC531 cells were intraportally implanted into the liver of Wag-Rij rats and re-isolated after 3, 6, 9, 14 and 21 days. Compared to control CC531 cells, claudin1 and claudin4 were among the ≥8 fold initially down-regulated genes. The co-culture of tumor cells with isolated rat hepatocytes and Kupffer cells did not induce down-regulation of either claudin1 or 4. When the environment effective on circulating tumor cells was simulated by cell culture conditions favoring their adhesion, only claudin4 showed augmented expression. Knockdown of claudin1 and claudin4 mediated by siRNA caused significantly increased migration and decreased clonogenic growth of tumor cells (p<0.05), but had no effect on their proliferation. These experimental results were paralleled by increased claudin1 and claudin4 expression in human colorectal cancer samples in UICC stages l-lll, as evaluated by real-time PCR. Increased claudin4 levels were correlated with significantly reduced overall survival (log-rank test, p=0.018). Further, significantly (p<0.05) reduced expression of claudin1 and claudin4 was observed in stage IV and liver metastasis by immunohistochemistry. In conclusion, sequential biphasic changes in claudin1 and claudin4 expression occur during the homing of colorectal cancer cells to the liver.

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 5252. doi:10.1158/1538-7445.AM2011-5252
Abstract 5256: Osteopontin-c and Osteopontin-b splicing isoforms activate important hallmarks of cancer contributing to prostate carcinoma progression
Authors: Tilli Tatiana M. , Matos Aline , Goulart Luis Ricardo , Weber Georg F. , Gimba Etel Rodrigues Pereira
Published: June 2012

Introduction: Osteopontin (OPN) is a secreted glycophosphoprotein and is involved in tumorigenesis and metastasis in many solid tumors, including prostate cancer (PCa). Alternative splicing of OPN mRNA leads to the expression of 3 isoforms, named OPNa, OPNb and OPNc. However, the expression pattern and the roles of these isoforms have not been previously characterized in PCa. Objective and Methodology: Herein we evaluated the expression pattern of these OPN isofoms in PCa and BPH (benign prostate hyperplasia) tissue samples by using qRT-PCR. ROC curve analysis evaluated the performance of OPN isoforms tissue levels as compared to PSA serum levels for the diagnosis of PCa. Additionally, we investigated the roles of these isoforms on PCa progression using PC3 cells ectopically overexpressing each OPN isoform and in vitro and in vivo assays. Results: Our data demonstrate that these 3 isoforms are overexpressed in PCa in relation to BPH tissue samples and that OPNc presents the highest expression level. ROC curve analysis demonstrate that OPNa, OPNb and OPNc expression levels perform better (AUC 0,9; 0,81 and 0,88, respectively, p< 0,0001) than PSA serum levels (AUC 0,52; p< 0,0001) for the differential diagnosis of PCa and BPH patients. Furthermore, OPN isoforms expression levels are positively correlated to tumor Gleason Score (p < 0,001). Cells overexpressing OPNc and OPNb, but not OPNa, significantly activate cell features typically related to key hallmarks of cancer, such as cell proliferation, migration, anchorage-independent growth and tumor formation in vivo in nude mice, reflecting the potential of these isoforms to active PCa tumor progression. Besides, OPNc seems also to in involved in PCa tumorigenesis, once stimulate the proliferation of RWPE1 prostate non- tumoral cells. Trying to describe the signaling pathways involved on OPNc and OPNb roles on activating PCa progression steps, we demonstrated that the use LY-294002 inhibitor significantly inhibited the proliferation of cells overexpressing OPNc and OPNb, suggesting that these OPN splicing isoforms on activating cell proliferation occurs via PI3K/Akt signaling pathways. Conclusions: Taken together, these results suggest that the evaluation of OPN splicing isoforms expression levels could be used as molecular parameter to improve the differential diagnosis of PCa in relation to BPH. Besides, we provide evidence that OPNc and OPNb activate important steps in PCa progression and hence could be important targets for the development of therapeutic approaches.

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 5256. doi:10.1158/1538-7445.AM2011-5256
Abstract 5279: Imaging of pancreatic cancer with activated cell penetrating peptide dendrimers
Authors: Metildi Cristina A. , Nguyen Quyen T. , Kaushal Sharmeela , Tran Cao Hop S. , Snyder Cynthia S. , Hoffman Robert M. , Tsien Roger Y. , Bouvet Michael
Published: June 2012

We have recently described novel activatable cell penetrating peptides attached to dendrimers (ACPPDs) which can selectively label tumors for real-time imaging during surgery. The aim of this study was to evaluate the ability of Cy5-labeled ACPPDs to visualize primary tumors and their margins in an orthotopic mouse model of pancreatic cancer. BxPC-3 or BxPC-3-RFP-expressing human pancreatic cancer cells were injected into the pancreas of 6-week old athymic mice to establish the orthotopic mouse models. ACPPs were synthesized on an automated peptide synthesizer by using standard protocols for fluorenylmethoxycarbonyl solid-phase synthesis. Peptides were cleaved off the resin, purified by HPLC, and conjugated to a generation 5 PAMAM dendrimer. Cy5 labeling was performed directly on the dendrimer. Dendrimers were then capped completely with Peg4 NHS ester. Tumor-bearing mice were injected with 20 nmoles of ACPPDs via tail vein 48 hours prior to imaging. Mice were first imaged non-invasively using OV-100 (Olympus) or Maestro (CRI) small animal imaging systems. Mice then underwent laparotomy. Resection of the primary pancreatic tumor using fluorescence guidance was performed using a MVX-10 fluorescence-dissecting microscope (Olympus) customized to allow the surgeon to see white-light reflectance, fluorescence, or the two superimposed in real time. At the conclusion of the experiments, H&E staining was used to confirm the pathological diagnosis of cancer in the resected specimens. We found that in the orthotopic BxPC3 mouse model of pancreatic cancer, intravenous injection of ACPPD showed bright fluorescence labeling of tumors compared to surrounding normal tissue. Co-localization studies showed a good correlation between ACPPD uptake and RFP tumor expression. Tumor margins were more clearly delineated with fluorescence imaging using ACPPDs compared to with white light reflectance alone. Post resection, the tumor bed was examined and imaged for residual tumor. With fluorescence-guided resection, the tumor bed was free of residual tumor, which was confirmed histologically. In this study, we have shown that ACPPDs can accurately and effectively label primary pancreatic tumors in an orthotopic mouse model of pancreatic cancer. This technology has the potential to improve surgical outcomes in patients with pancreatic cancer.

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 5279. doi:10.1158/1538-7445.AM2011-5279
Abstract 5282: Pretargeted immunoPET for imaging human colonic cancer in a mouse model
Authors: Schoffelen Rafke , Franssen Gerben M. , McBride William J. , Disselhorst Jonathan A. , Sharkey Robert M. , Laverman Peter , van der Graaf Winette T. A. , Oyen Wim J. G. , Goldenberg David M. , Boerman Otto C.
Published: June 2012

Objective: Molecular imaging with pretargeting bispecific antibodies allows rapid and specific targeting of tumors for PET imaging. In this study, pretargeted immunoPET with a bispecific monoclonal anti-carcinoembryonic antigen (CEA; CEACAM5) × anti-hapten antibody (bsMAb) and a small (1.5 kD) peptide labeled with a short-lived positron-emitter 68Ga was compared to FDG for detection of intraperitoneal CEA-expressing human colonic tumor xenografts in nude mice.

Methods: In BALB/c nude mice LS174T human colonic tumor cells were injected intraperitoneally. One group (n=5) received 5 MBq FDG i.v., and another group (n=5) received the bsMAb i.v. and 5 MBq of 68Ga-labeled peptide i.v. 16 h later. One hour after the injection of the peptide or FDG, PET/CT images were acquired. One day later the same procedure was repeated vice versa, and after microPET imaging the uptake of the 68Ga or 18F in dissected tissue was determined.

Results: Within one hour, specific tumor targeting of 68Ga-labeled peptide (23.4 ± 7.2% ID/g) combined with the low background activity levels resulted in the clear visualization of the small intra-abdominal tumor lesions (1.5-5 mm). High tumor/background radioactivity concentration ratios were obtained (e.g. tumor/intestines 57.5 ± 22.4). FDG localized efficiently in the tumors (8.7 ± 3.1 % ID/g), but with physiological uptake in various normal tissues (ratio tumor/intestines 4.0 ± 0.9).

Conclusion: Pretargeted immunoPET performs exceptionally well with short-lived radionuclides, and is a highly sensitive procedure for dectection of small tumor deposits that is also more specific than FDG-PET.

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 5282. doi:10.1158/1538-7445.AM2011-5282
Abstract 5288: Tumor-endothelial 3D spheroids for dynamic imaging of cancer progression
Authors: Upreti Meenakshi
Published: June 2012

The increasing use of anti-angiogenic drugs for the treatment of cancer has emerged from the explosion of knowledge about the process of tumor angiogenesis. However, the clinical results of using such drugs have been relatively modest and new agents are likely needed. A robust pre-clinical model of cellular mechanisms governing tumor angiogenesis may improve our ability to develop strategies for tumor specific drug delivery with superior pharmacokinetics, controlled biodistribution, efficacy, and safety profiles. We have developed a system to grow 3D-cultures of tumor and endothelial cells in hanging drops of medium. Subsequently, we transplant these spheroidal cultures into the dorsal skin fold window chamber of mice for intravital multiphoton imaging of neovasculature and disease progression. Our initial observation was that there was a marked difference in neovascularization from the GFP-tumor-endothelial spheroids in comparison to GFP-tumor spheroids in the window chamber mouse model. Molecular analysis using an antibody array showed a pronounced upregulation of angiogenic factors in the tumor tissue derived from the tumor-endothelial spheroid compared to the spheroid grown with tumor cells alone. Interleukin-1α, FGF-1α, CCN3/NOV, PIGF-2, MMP-3, MMP-8 and MMP-9 were seven identified proteins that showed distinct differences in expression between the two spheroid types. Further, the relative increase in tumor growth of tumor-endothelial spheroids implanted on the rear hind limb was much faster than the tumor cell alone spheroid and resulted in evidence of greater metastasis to the lung. We thus strongly believe that the 3D tumor-endothelial spheroid implanted in the dorsal fold window chamber of mice is a more realistic and informative model for dynamic imaging of critical aspects of tumor angiogenesis and the study of metastasis. Efforts are underway to monitor molecular and cellular events related to radiation exposure combined with anti-angiogenic agents of varying mechanisms of action to determine prudent new avenues for therapeutic success.

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 5288. doi:10.1158/1538-7445.AM2011-5288
Abstract 5288A: Multivalent fluorescent probes for in vivo tumor targeting
Authors: Zhang Ning , Kim Jae-Beom , Lim Ed , Ansaldi Dan , Ang Angel , Singh Raj
Published: June 2012

Conventional fluorescence probes are monovalent molecules that interact with cellular or extra-cellular target molecules through affinity binding. To improve the binding affinity and sensitivity of detection of the fluorescence probe, we describe a novel strategy for the synthesis designed to contain multiple targeting moieties and a near infrared fluorescent dye Iflour750 for optimal in vivo detection. In this study, we applied several multivalent probes to in vivo tumor targeting and monitored the targeting process using fluorescence imaging. Deoxyglucose based fluorescence probes have been applied to tumor labeling as the high metabolic rate of the tumor cells causes preferential labeling of the tumor mass. With a multivalent 2-deoxy-D- glucose Iflour750 (2-DG-IF750) probe, we demonstrated sensitive in vivo targeting as compared to a control mono-valent 2DG probe in several tumor models, including PC3M-luc2 prostate tumor cells, MDA-MB-231-luc2 mammary fat tumor cells as well as LL/2-luc and H460-luc2 lung cancer cells. Distinct tumor signal was visualized within a few hours after intravenous delivery and reached the peak of signal/background ratio between 6-24 hours. With a multivalent cyclooxygenase (COX) binding fluorescence probe Indomethacin-IF750, we observed an interesting targeting of COX2 negative colon tumor cells HCT116-luc2, but not the COX2 positive HT29-luc2, hypothetically due to selective binding to COX1. We also tested a multivalent RGD probe for targeting integrin avb3, the expression of which is associated with tumor angiogenesis and metastasis. With our iFlur750-(RGD)4 probe, we demonstrated in vivo targeting of U87-MG-luc2, HCT116-luc2 and HT29-luc2 tumor cells. Finally, we demonstrated that optical imaging was conveniently applied to evaluating the PK/PD profile of the probes. Our multivalent probes showed a fast clearance with a half life of less than 1 hour, which is a desirable feature for achieving maximal tumor/background contrast. In summary, we have developed a new class of multi-valent fluorescence probes with improved specificity and sensitivity of tumor targeting as compared to mono-valent analogs. Utility of this class of multivalent probes is likely to pass beyond pre-clinical models, as imaging guided tumor surgery is on the verge of 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 5288A. doi:10.1158/1538-7445.AM2011-5288A
Abstract 5293: Mixed micelles of triblock copolymers enhance delivery of indocyanine green for fluorescent tumor imaging
Authors: Mount Christopher , Kim Tae Hee , Dulken Benjamin , Li Xingde , Gombotz Wayne , Pun Suzie
Published: June 2012

The goal of this study is to develop formulations for non-invasive, near-infrared detection of tumors. Indocyanine green (ICG) is an FDA-approved near-infrared (NIR) imaging agent that is clinically used for angiography and evaluation of liver function. ICG could potentially be used as a NIR fluorescence imaging agent for shallow tumors such as breast cancers. To fulfill this potential, formulations that improve the stability of ICG and direct its accumulation in tumors are necessary. We have previously described Pluronic F127 copolymer micelles that stabilize ICG, enhance its stability, and facilitate tumor accumulation in vivo after systemic administration. A major advantage of Pluronic F127 is its temperature-sensitive behavior that results in more stable micelle formulations at body temperature. However, Pluronic F127 micelles are not stable at room temperature, making micelle preparation and handling challenging. We hypothesized that mixed micelles formed from both Pluronic F127 and a temperature insensitive triblock copolymer composed of poly(ethylene oxide) and poly(3-hydroxybutyrate) (PEO-PHB-PEO), would result in micelles that are both easy to formulate at room temperature and that demonstrate increased stability at body temperature. Micelle formulations with various ratios of Pluronic F127: PEO-PHB-PEO were prepared and loaded with ICG. The micelle stability was determined by assessment of critical micelle concentration measurements, and time-course fluorescence assays were conducted to assess the ability of each micelle formulation to stabilize ICG fluorescence in buffer conditions. The ICG-loaded micelles were administered to tumor-bearing mice by tail vein injection and tumor localization was monitored by non-invasive fluorescence imaging in live mice. The polymer ratio used in micelle formulation was found to play a significant role in the ability of each preparation to stabilize ICG fluorescence Mixed micelles were found to enhance the stability of ICG fluorescence in buffer conditions, and CMC was shown to be dependent on polymer ratios. In vivo, mixed micelles were found to be more effective at maintaining ICG fluorescence in the bloodstream and achieved higher fluorescence signals in the tumor tissues compared with either PEO-PHB-PEO or Pluronic 127 micelles. These results suggest that the mixed micelle formulations offer a promising route to stabilizing these nanoparticles for improved delivery of NIR fluorescent contrast agents to tumors for imaging 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 5293. doi:10.1158/1538-7445.AM2011-5293
Abstract 5294: Real-time optical imaging of nanoparticle biodistribution in vivo
Authors: van de ven-Moloney Anne L. , Haley O'Hara , Kim Pilham , Yun Seok-Hyun , Ferrari Mauro , Decuzzi Paolo
Published: June 2012

High-resolution optical imaging provides the opportunity to visualize the transport of systemically injected nanoparticle systems along a series of biophysical barriers to their site of action. Data collected using this approach can be used to simulate, predict, understand, and improve the delivery of therapeutics and/or contrast agents to solid tumors. Here we present evidence that tailoring the physical properties of nanoparticle systems can improve their accumulation at disease sites. Using confocal technologies, we investigated the dynamics of nanoporous silicon particles in the microvasculature of normal and tumor-bearing mice. The biodistribution of intravenously injected particles of different size, shape, and surface properties were monitored in real-time. In organs of the reticuloendothelial system (RES), the rate of particle accumulation, as well as the total number of particles accumulated, was highly dependent on particle shape. Particles which preferentially accumulated in tumors were different than those which accumulated in the RES organs, suggesting that particle shape is an important design parameter for organ-specific delivery. The importance of modifying particle surface was evaluated in melanoma-bearing mice by systemically administering particles with and without endothelial-specific targeting moieties. The addition of targeting moieties was found to improve tumor-specific accumulation as much as changing particle shape. We have independently validated these in vivo findings and begun to elucidate the mechanisms of particle accumulation using inductively coupled plasma atomic emission spectrometry, immunocytochemistry, immunohistochemistry, and mathematical modeling.

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 5294. doi:10.1158/1538-7445.AM2011-5294
Abstract 5304: A genetically engineered mouse model for GBM wherein Akt kinase activity can be monitored non-invasively in real-time
Authors: Galbán Stefanie , Lemasson Benjamin , Lafferty Michael J. , Li Fei , Heist Kevin , Galban Craig J. , Ross Brian D. , Rehemtulla Alnawaz
Published: June 2012

Approximately 30-40% of human gliomas exhibit mutations in the tumor suppressor gene PTEN resulting in deregulation of the phosphoinositide 3-kinase/Akt survival signaling pathway. In a significant number of GBMs tumor initiation is additionally driven by an oncogenic signal stemming from the gene locus amplification of the Platelet derived growth factor receptor (PDGFR), also leading to Akt and mammalian target of rapamycin (mTOR) activation. Phosphorylated, active Akt controls a plethora of cellular responses by regulating a large number of substrates, such as GSK-3, BAD, Forkhead transcription factors (FOXO), and MDM2. Elevated Akt activity increases tumor cell growth, survival and impairs apoptosis. Thus blocking Akt phosphorylation to treat cancer in particular gliomas has therapeutic potential. Here we demonstrate the pre-clinical use of a bioluminescent molecular reporter to evaluate Akt kinase inhibition in real time in a genetically engineered PDGF-driven PTEN-deficient mouse model of GBM. Glial cell specific delivery of the bioluminescent reporter was achieved by RCAS-TVA technology. In brief, we utilized genetically engineered PTEN loxP/loxP,

Ink4a-Arf -/-, nestin-TVA transgenic animals and delivered the Akt reporter along with Cre recombinase and PDGF by intracranial implantation of chicken cells expressing avian virus containing the specific cargo. PTEN deletion in nestin positive cells resulted in increased Akt kinase phosphorylation as demonstrated by western blotting. Tumor growth was monitored by MRI and Bioluminescence imaging (BLI) technology. The design of the previously described Akt reporter allows for detectable bioluminescence only in the absence of Akt kinase activity due to the reconstitution of the wt luciferase enzyme. To evaluate the therapeutic potential of PI3-kinase- and Akt inhibitors in this pre-clinical GBM model, tumors were treated with either perifosine or API-2. Increased bioluminescence activity was observed in gliomas in a time- and dose-dependent manner with both inhibitors. These findings demonstrate that the Akt reporter provided a quantitative surrogate for Akt activity in PTEN-deficient gliomas. In conclusion we have provided a novel approach of pairing molecular imaging with a murine GBM model to investigate targeted agents. This may aid the future identification of most efficacious drug combinations impinging on PI3-kinase/Akt signaling in gliomas.

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 5304. doi:10.1158/1538-7445.AM2011-5304
Abstract 5312: Near-infrared multichannel Raman spectroscopy with a 1064-nm excitation wavelength for ex vivo diagnosis of gastric cancer
Authors: Kikuchi Hirotoshi , Kawabata Toshiki , Okazaki Shigetoshi , Hiramatsu Yoshihiro , Baba Megumi , Ohta Manabu , Kamiya Kinji , Tanaka Tatsuo , Konno Hiroyuki
Published: June 2012

Background: Gastric cancer is one of the major causes of death in Japan. Endoscopic submucosal dissection (ESD) has been developed for the treatment of early cancers. ESD needs accurate diagnosis of the demarcation line, pathological type and depth of cancer lesions. We have previously reported, using biopsy specimens, the usefulness of the 1064-nm near-infrared multichannel Raman spectroscopy (RAS) system as a novel diagnostic modality for gastric cancer (J Gastroenterol.43(4), 2008). However, our study might not have reflected in vivo use of RAS due to a lack of tissue other than the mucosal layer in the biopsy specimens. Here, we used the 1064-nm near-infrared multichannel RAS ex vivo for optical diagnosis of gastric cancer in surgically resected stomach.

Methods: A total of 213 Raman spectra were obtained from 12 cancer lesions and their corresponding non-neoplastic areas in 10 stomachs following resection for gastric cancer. Without any pretreatment, the fresh specimens were measured with a near-infared multichannel Raman spectroscopic system with an excitation wavelength of 1064nm, and Raman spectra specific for the specimens were obtained. To develop optical diagnostic systems for gastric cancer, principal component analysis (PCA) of all the Raman spectra was performed.

Results: The averaged Raman spectra of the cancer lesions could be distinguished from those of the non-neoplastic regions. Discrimination analysis of cancer from non-neoplastic regions with 10 principal components revealed that sensitivity, specificity and accuracy of cancer diagnosis was 73%, 73% and 72%, respectively. RAS discriminated between differentiated and undifferentiated cancers, early and advanced cancers, as well as T1a (M) and T1b (SM) cancers with high accuracy (98%, 93% and 98%, respectively).

Conclusions: The 1064-nm near-infrared multichannel RAS system is useful not only for gastric cancer detection, but also for discrimination between differentiated and undifferentiated, as well as early and advanced cancers. RAS could help establish indications for endoscopic treatment by eliminating cancer lesions with an undifferentiated component or submucosal invasion.

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 5312. doi:10.1158/1538-7445.AM2011-5312
Abstract 5315: PET imaging with the proliferation tracer 18F-FLT as early, non-invasive predictor of everolimus effect on tumor growth: Studies in human neuroendocrine tumor xenografts in mice
Authors: Johnbeck Camilla Bardram , Jensen Mette Munk , Hag Anne Mette Fisker , Madsen Jacob , Knigge Ulrich , Kjaer Andreas
Published: June 2012

Background and aim: Everolimus (RAD001), an oral mTOR inhibitor has shown promising results in the treatment of several types of cancer including neuroendocrine tumors. With the expanding numbers of clinical treatment protocols there is a need for early, non-invasive predictors of treatment response. We hypothesized that PET imaging with the proliferation tracer 3′-Deoxy-3′-[(18)F]fluorothymidine (FLT) could serve as such a predictor. Therefore, we studied in human neuroendocrine tumor xenografts in mice whether PET imaging with FLT could predict, at an early time-point, the effect of everolimus on tumor growth.

Methods: In vivo uptake of FLT in human neuroendocrine xenografts (H727) in mice was studied at baseline when tumors were on average 140 mm3. The mice were randomized into two groups. One group of mice (n=10 tumors) were treated with daily i.p. injections of everolimus (5 mg/kg) for 10 days while another group of mice (n=10 tumors) served as control and was given the same volume of vehicle i.p. The mice were FLT scanned at day 0, 1, 3, 7 and 10. Each PET scan was acquired over 15 min 1 h after injection in a tail vein of 10 MBq FLT. In addition, a CT-scan was performed for calculation of tumor volume. The tumors were defined on PET/CT images and FLT uptake was calculated as mean standardized uptake values (SUV).

Results: Everolimus treated mice showed a clear reduction in tumor growth compared to the vehicle group at day 7 and 10 (P<0.0001). At day 7 the relative tumor volumes (day 7/day 0) were 1.78±0.10 in the everolimus group and 2.77±0.11 (407 mm3) in the control group. At day 10 the relative tumor volumes (day 10/day 0) were 2.17±0.15 (304 mm3) in the everolimus group and 3.50±0.13 (518 mm3) in the vehicle group. The relative FLT SUV value on day 10 showed significantly reduced uptake (P=0.003) in the everolimus group (0.91±0.06) compared to the control group (1.16±0.04). In the everolimus group FLT uptake at day 3 predicted relative tumor size both at day 7 (R2=0.53; P=0.017) and day 10 (R2=0.60; P=0.024). FLT uptake at day 1 also predicted tumor growth, although only borderline significant, at day 3 (R2=0.38; P=0.060), 7 (R2=0.39; P=0.055) and 10 (R2=0.45; P=0.069).

Conclusion: FLT-PET imaging as early as 1 or 3 days after treatment initiation with everolimus predicts neuroendocrine tumor growth over the first 10 days of treatment. We suggest that FLT-PET is a promising tool for early prediction of effect of everolimus in patients with neuroendocrine tumors and may be used for tailoring therapy.

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 5315. doi:10.1158/1538-7445.AM2011-5315
Abstract 5323: Staging of metastatic pancreatic cancer is facilitated by fluorescence laparoscopy
Authors: Metildi Cristina A. , Kaushal Sharmeela , Hardamon Chanae R. , Snyder Cynthia S. , Luiken George A. , Talamini Mark A. , Hoffman Robert M. , Bouvet Michael
Published: June 2012

The aim of this report was to improve the real-time imaging of fluorescence laparoscopy with the introduction of an LED light source. We also attempted to determine the optimal fluorophore to improve accurate identification and localization of tumor deposits without the loss of background illumination. Human pancreatic cancer orthotopic models were established with intraperitoneal injections of RFP-expressing FG or BxPC-3, or non-fluorescent BxPC-3 human pancreatic cancer cells into 6-week-old female athymic mice. One to 2 weeks post implantation, diagnostic laparoscopy was performed with a Stryker L9000 LED light source or a Stryker X8000 xenon light source 24 hours after tail vein injection of Alexa 488-conjugated anti-CEA. An attempt was made to detect and localize all cancer lesions under each light mode. After laparoscopy, the animals were sacrificed and abdominal cavities exposed. Images of the lesions were obtained with the Maestro CRI Small Animal Imaging System serving as a positive control. Tumors were collected and processed for histologic review. Fluorescence laparoscopy with the use of a 495-nm emission filter and an LED light source enabled real-time visualization of the fluorescence-labeled tumor metastases in the peritoneal cavity. With adjustments to the LED light source, we could simultaneously detect tumor lesions of different fluorescent colors and surrounding structures with minimal autofluorescence. Overall, fluorescence laparoscopy using the LED light source afforded accurate detection of more lesions compared to standard xenon bright field laparoscopy. In addition, several tumor deposits of less than 1mm were identified and localized under FL. Such lesions were not detected under bright field laparoscopy. All identified lesions, when possible, were verified histologically. In this study, we have thus demonstrated that using an LED light source with adjustments to the red, blue and green wavelengths, we can simultaneously identify fluorescent tumor metastases of different wavelengths without compromising background illumination. The further development of this technology can serve as a novel tool in the staging and treatment of pancreatic cancer.

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 5323. doi:10.1158/1538-7445.AM2011-5323
Abstract 5325: Localized tumor growth in bone: Quantification of tumor burden, bone destruction, and weight-bearing capability in MDA-MB-231 human mammary carcinoma xenograft-bearing immunodeficient rats
Authors: Brune Kellie A. , Misener Elizabeth A. , Shannon Harlan , Wolos Jeffrey A.
Published: June 2012

Metastatic bone disease is common in multiple myeloma, breast, prostate, and lung cancer patients and is a frequent cause of morbidity in advanced disease. Metastatic bone tumors destroy bone and cause severe bone remodeling which leads to structural weakening and bone fractures and often results in severe bone pain in a large percentage of patients.

These studies examined tumor growth, bone erosion, and pain in a nude rat model. A surgical defect was created in the tibia, exposing the marrow cavity. Luciferase-expressing MDA-MB-231 mammary tumor cells were injected into the exposed bone cavity. Rats inoculated with tumor cells were treated with either doxorubicin (3 mg/kg/week, iv) or risedronate (80 ug/kg/day, ip). Animals were monitored weekly for tumor burden by optical imaging and for bone erosion by CT. In addition to clinical observations, weight bearing was measured using an incapacitance tester with separate force transducers for each hind paw.

Compared to controls, rats treated with doxorubicin demonstrated a significant decease in luminescence, indicating tumor growth inhibition (bone protection). Decreased luminescence correlated with sparing of the bone as measured by CT. In contrast, the bisphosphonate, risedronate, had limited effect on tumor growth, but preserved bone integrity. In both treatments, protection of bone was associated with normalization of weight-bearing. This finding supports the premise that pain in metastatic bone cancer is attributable to bone loss (destruction) and remodeling. Weight-bearing data correlated directly with clinical observations This model, leveraging multiple imaging modalities, enables longitudinal and quantitative assessment of tumor growth; bone loss, remodeling and sparing, and weight-bearing in test animals that provides a sensitive and robust screening tool to evaluate compounds for anti-tumor, bone-sparing and pain amelioration effects.

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 5325. doi:10.1158/1538-7445.AM2011-5325
Abstract 5326: Quantitative molecular profiling of biomarkers for pancreatic cancer with quantum dots
Authors: Searson Peter C. , Lee Kwan Hyi
Published: June 2012

The detection of cancer biomarkers is important for diagnosis, disease stage forecasting, and clinical management. Since tumor populations are inherently heterogeneous, a key challenge is the quantitative profiling of membrane biomarkers, rather than secreted biomarkers, at the single cell level. The detection of cancer biomarkers is also important for imaging and therapeutics since membrane proteins are commonly selected as targets. Many methods for detection of membrane proteins yield ensemble averages and hence have limited application for analysis of heterogeneous populations or single cells. Fluorescence-based methods allow detection at the single cell level, however, photobleaching presents a major limitation in obtaining quantitative information. Quantum dots overcome the limitations associated with photobleaching, however, the development of quantum dot – antibody (QD-Ab) conjugates that allow quantitative profiling of biomarkers has remained challenging. Here we demonstrate quantitative in vitro profiling and multiplexing of molecular biomarkers associated with precursor lesions of pancreatic adenocarcinoma using QD-Ab conjugates. We demonstrate quantitative spatial profiling of several biomarkers for pancreatic cancer, including mesothelin, prostate stem cell antigen, and claudin-4 in several pancreatic cancer cell lines and a normal pancreas cell line. We also show tumor targeting in a mouse model.

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 5326. doi:10.1158/1538-7445.AM2011-5326
Abstract 5329A: Micro-CT enables microlocalization and quantification of Her2-targeted gold nanoparticles within tumor regions
Authors: Hainfeld James F. , O'Connor Michael J. , Dilmanian Avraham , Slatkin Daniel N. , Adams Douglas J. , Smilowitz Henry M.
Published: June 2012

Gold nanoparticles are of interest as potential in vivo diagnostic and therapeutic agents, as X-ray contrast agents, drug delivery vehicles and radiation enhancers. The aim of this study was to quantitatively determine their targeting and microlocalization in mouse tumor models after intravenous injection by using micro- CT. Gold nanoparticles (15 nm) were coated with polyethylene glycol and covalently coupled to anti-Her2 antibodies (Herceptin). In vitro, conjugates incubated with Her2+ (BT-474) and Her2- (MCF7) human breast cancer cells showed specific targeted binding with a Her2+ to Her2- gold ratio of 39.4± 2.7:1. Nude mice, simultaneously bearing subcutaneous Her2+ and Her2- human breast tumors in opposite thighs were prepared. Gold nanoparticles alone, conjugated to Herceptin or to a non-specific antibody were compared. After intravenous injection of the gold nanoparticles, gold concentrations were determined by atomic absorption spectroscopy. Microlocalization of gold was carried out by calibrated micro-CT, giving both the radiodensities and gold concentrations in tumor and non-tumor tissue. All gold nanoparticle constructs showed accumulation, predominantly at tumor peripheries. However, the Herceptin-gold nanoparticles showed the best specific uptake in their periphery (15.8± 1.7% injected dose g-1), 1.6-fold higher than Her2- tumors and 22-fold higher than surrounding muscle. Imaging readily enabled detection of small, 1.5-mm-thick tumors. In this pre-clinical study, antibody-targeted 15 nm gold nanoparticles showed preferential uptake in cognate tumors, but even untargeted gold nanoparticles enhanced the visibility of tumor peripheries and enabled detection of millimeter-sized tumors. Micro-CT enabled quantification within various regions of a tumor.

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 5329A. doi:10.1158/1538-7445.AM2011-5329A
Abstract 5331: CHK1 inhibition enhances chemosensitivity of p53 deficient osteosarcoma cells
Authors: Xu Gufeng , Wang Hongmei , Rainusso Nino C. , Flores Ricardo J. , Triche Timothy , Man Tsz-Kwong , Lau Ching C.
Published: June 2012

Osteosarcoma is the most common malignant bone tumor in children. Using expression profiling, we have previously identified a 45-gene chemoresistance signature in osteosarcoma that can predict tumor response to neo-adjuvant chemotherapy. One of the signature genes is CHEK1, which was expressed significantly higher in osteosarcomas that respond poorly to neoadjuvant chemotherapy. CHEK1 encodes a Serine/threonine-protein kinase CHK1 that regulates both G2/M and S phases of the cell cycle mainly through phosphorylation of CDC25, and particularly controls the entry into mitosis. In this study, we used two independent short hairpin RNA (shRNA) constructs to knock-down CHEK1 expression in a p53-mutated osteosarcoma cell line 143B and a p53- wild type osteosarcoma cell line U2OS. The results show that the stably transduced CHEK1 knock-down 143B cells, but not U2OS cells, became more sensitive to both doxorubicin and cisplatin treatment relative to the parental or scrambled control cells. The results of the cytotoxicity assay were confirmed by clonogenic assay using 143B and U2OS stable transfectants. Using a CHK1 inhibitor UCN-01, we found that mutation status of p53 in different osteosarcoma cells lines correlated with their sensitivity to doxorubicin or cisplatin in the presence of UCN-01. Using flow cytometry, we also validated the activity of UCN-01 in abolishing the cell cycle arrest induced by doxorubicin or cisplatin treatment in 143B cells.

In summary, our results confirm that CHEK1 expression is not only a potential biomarker for predicting chemoresistance in osteosarcoma, but also potentially represents a therapeutic target for overcoming chemoresistance in osteosarcoma with the use of small molecule CHK1 inhibitors. Further experiments involving in vivo orthotropic xenograft mouse model with both CHEK1 knock-down osteosarcoma cells and CHK1 inhibitors is underway.

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 5331. doi:10.1158/1538-7445.AM2011-5331
Abstract 5332: Evaluation of GD2 expression in patients with osteosarcoma
Authors: Tarim John , Sowers Rebecca S. , Piperdi Sajida , Khanna Chand , Gorlick Richard G.
Published: June 2012

GD2 is a disialoganglioside that is expressed on the cell surface in specific normal and malignant human tissues. Tumor specific cell surface antigens serve as important targets in cancer therapy. Anti-GD2 therapy using antibodies targeted to the cell surface antigen GD2 to induce antibody-dependent cellular cytotoxicity has been proven effective in treating GD2 expressing tumors like neuroblastoma and melanoma. Prior studies of osteosarcoma have shown GD2 to be expressed in malignant cells of osteosarcoma patients. In this study, the expression of GD2 in osteosarcoma will be evaluated further. A previously created and described tissue microarray was stained with 14.G2a, a murine monoclonal anti-GD2 antibody that was obtained from the National Cancer Institute. The intensity and location of tissue staining were assessed by a comparison between the positive and negative control slides. To evaluate GD2 expression quantitatively a cell-based ELISA was performed on different osteosarcoma patient derived cell cultures. The results of the tissue microarray showed that 34.8% of patient samples stained positive for GD2 while 60.9% of samples showed intermediate staining and only 4.3% of samples showed negative staining for GD2 (n=88). Nearly all of the osteosarcoma cell lines (n=24) showed levels of GD2 expression comparable to the neuroblastoma and fibrosarcoma cell lines and in some cases GD2 expression was significantly greater. Anti-GD2 therapy has been proven effective in treating patients with neuroblastoma and melanoma. The findings in this paper indicate that osteosarcomas express GD2 to a similar extent as neuroblastomas. These results would suggest clinical trials are worthwhile to further evaluate the benefit of anti-GD2 therapy in patients with osteosarcoma.

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 5332. doi:10.1158/1538-7445.AM2011-5332
Abstract 5335: The histone deacetylase inhibitor MS-275 sensitizes osteosarcoma cells and osteosarcoma lung metastases to FasL-induced cell death by the downregulation c-FLIP
Authors: Rao-Bindal Krithi , Kleinerman Eugenie S.
Published: June 2012

The purpose of this study was to determine the effects of the histone deacetylase inhibitor, MS-275, on the Fas signaling pathway and susceptibility of osteosarcoma (OS) to FasL-induced cell death. OS metastasizes almost exclusively to the lungs. We have shown that Fas expression by OS cells inversely correlates with their metastatic potential. Fas+ cells are rapidly eliminated when they enter the lungs via interaction with FasL, which is constitutively expressed in the lungs. OS cells that are Fas− escape this FasL-induced apoptosis and survive in the lung microenvironment. Moreover, upregulation of Fas expression on established OS lung metastases results in tumor regression. Therefore, agents that upregulate Fas or activate the Fas signaling pathway may have therapeutic potential. These investigations utilized the Fas− metastatic osteosarcoma cell lines LM7 and CCH-OS-D. Treatment of OS cells with 2µM MS-275 sensitized cells to FasL-induced cell death in vitro, as quantified by MTT, trypan blue and clonogenic assays. We have demonstrated that blocking Fas signaling by transfecting cells with a FADD dominant-negative (FDN) plasmid, inhibited MS-275-induced sensitization to FasL-mediated cell death, suggesting the involvement of the Fas pathway in this mechanism. We found that treatment of OS cells in vitro did not alter the expression of Fas on the cell surface, rather it resulted in the downregulation of the anti-apoptotic protein, c-FLIP (cellular FLICE-inhibitory protein), which was determined to be a result of MS-275-induced downregulation of FLIP mRNA. Downregulation of c-FLIP correlated with caspase activation and induction of apoptosis. Treatment of nu/nu-mice with established OS lung metastases with oral MS-275 resulted in tumor regression, increased apoptosis and a significant inhibition of c-FLIP expression in tumors. Histopathological examination of mice receiving oral MS-275 showed no evidence of toxicity. Overall, these data suggest that the mechanism by which MS-275 sensitizes OS cells and OS lung metastases to FasL-induced cell death may be by a direct reduction in the expression of c-FLIP.

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 5335. doi:10.1158/1538-7445.AM2011-5335