Citations

Abstract B128 Background The B vitamin folate affects colorectal carcinogenesis through effects on nucleotide synthesis and possibly DNA methylation. Animal models and epidemiologic evidence suggest that folate from diet and supplements can prevent the development of colorectal cancer (CRC), but that high folate intake after adenomas or cancer are established may accelerate progression or recurrence. The chemotherapeutic agent 5-fluorouracil inhibits thymidylate synthase, a folate-metabolizing enzyme, and the effect of folate intake on treatment efficacy is unknown. Supplement use and folate intake are high among adults in the U.S., particularly with food supply fortification, and higher still among cancer patients and survivors. However, few studies have addressed use of folic acid-containing supplements (FAS) among colorectal cancer patients, how use changes after diagnosis, and what factors determine changes in FAS use. Methods The Colon Cancer Family Registry (CCFR) is a multicenter study of colorectal cancer cases, their family members and controls, recruited since 1998 at six sites in the United States, Australia and Canada. The current analysis includes 1,092 CRC cases with epidemiologic data available from questionnaires administered at enrollment, asking about supplement use and other risk factors before diagnosis, and from follow-up questionnaires about 5 years later. Baseline characteristics for cases who began using FAS (including multivitamins) after diagnosis were compared to those for cases who used FAS neither before nor after diagnosis. We used logistic regression models to evaluate associations between age, sex, CCFR site, race, education, income, lifetime exercise, smoking, body mass index, and diet and change in FAS use, adjusting each model for age, sex and site, when appropriate. Results FAS use before CRC diagnosis was 35.4%, while 55.1% of cases used FAS after diagnosis. Women were more likely to begin FAS use after diagnosis (OR 1.60, 95% CI 1.17-2.19). Current smokers were less likely than nonsmokers to begin FAS use (OR 0.63, 95% CI 0.40-0.97), as were those consuming more red meat (OR 0.38, 95% CI 0.21-0.70 for those in the highest versus lowest intake categories, ptrend=0.012). Subjects with higher fruit intake were more likely to begin FAS use (OR 1.95, 95% CI 1.16-3.30 for highest versus lowest intake, ptrend=0.013). We also observed a suggestive association between lifetime physical activity and change in FAS use for active versus less active subjects (OR 1.48, 95% CI 1.01-2.16), though there was no trend with increasing levels of physical activity (ptrend=0.27). Finally, we found that residents of non-U.S. countries were less likely to begin FAS use (OR 0.57, 95% CI 0.33-0.96 for Ontario, Canada and OR 0.21, 95% CI 0.11-0.38 for Australia). Conclusions: Our analysis showed substantial increases in the use of folic acid-containing supplements after diagnosis with colorectal cancer in CCFR participants, especially among women, U.S. residents, nonsmokers, and those who consumed more fruit and less meat. This study begins to characterize CRC patients likely to be using FAS, and suggests that its use is widespread. This finding is notable given evidence that folate may accelerate progression of colorectal cancer, and the unknown effect that FAS intake may have on the efficacy of cancer treatment and on survival. Citation Information: Cancer Prev Res 2008;1(7 Suppl):B128.

Abstract A61 Background Patients with Barrett's esophagus (BE) and dysplasia are ideal candidates for chemopreventive strategies to reduce cancer risk. Difluoromethylornithine (DMFO) is a promising chemopreventive agent that inhibits polyamine synthesis involved in the regulation of cell growth and differentiation. We conducted a pilot study to examine the effects of DFMO on esophageal histopathology, mucosal polyamine content, and gene expression. Materials and Methods Patients (n=10) with histologically confirmed BE and low grade dysplasia were enrolled in a single-arm study of DFMO (0.5 g/m2/d) given continuously for 6 months. Esophagoscopy with biopsies (4 quadrants every 1 cm) was performed at baseline, 3 and 6 months, and at 12 months (where available). Grading of dysplasia was performed by a GI pathologist blinded to clinical/biomarker data. Audiology was also performed. Mucosal polyamine content was measured by high-performance liquid chromatography, and analyzed using paired t-tests. Gene expression profiling was performed using a cDNA two-color chip, and was compared between baseline and 6 months. Expression data was normalized using the two-channel fastlo routine and differential expression was computed using a Wilcoxon signed-rank test. Results After 6 months of DFMO treatment, histopathological response data demonstrate regression of dysplasia (n= 1), stable disease (n= 8), and progression of dysplasia (n= 1). Within the stable category, 2 patients with extensive low grade dysplasia showed only focal dysplasia based upon 4 or more biopsies at 6 months. Histolopathological improvements seen at 6 months were maintained at 12 months. Overall, DFMO was well tolerated. One patient had subclinical, unilateral ototoxicity. Modulation of polyamines (spermine, spermidine, putrescine, histamine) was shown only for putrescine which decreased with treatment (6 mo., p=0.07) and showed recovery to baseline at 12 months (p= 0.01). Gene expression profiling revealed modulated genes of potential biological importance (KLF5, KAL1, RFC5, TIMM8a, TC10) and of these, Krüppel-like factor 5 (KLF5) was downregulated whereas the others were upregulated. Conclusion >Further study of the chemopreventive effect of DFMO upon BE with dysplasia is suggested. DFMO treatment suppressed mucosal putrescine levels and downregulated KLF5, an important mediator of cell proliferation. Citation Information: Cancer Prev Res 2008;1(7 Suppl):A61.

Abstract Despite ongoing advances in drug discovery science, anticancer agent development remains a laborious, time-consuming process. Discouragingly, the overall approval rate for new oncology drugs is approximately ∼ 5%, with estimated R & D costs ranging from $0.8–1.7 billion for each new agent. Lack of efficacy, suboptimal formulation, poor bioavailability and other factors contribute to the high pre-registration attrition rate, suggesting an urgent need for process enhancements that can facilitate earlier differentiation between viable and non-viable candidate compounds. In January 2006, the U.S. Food and Drug Administration (FDA) issued a guidance document on Exploratory IND Studies (a.k.a. phase 0 trials). In brief, phase 0 trials should (a) be conducted prior to traditional phase I, dose-limiting toxicity trials; (b) involve limited human exposure (usually ≤ 30 subjects); (c) have no therapeutic or diagnostic intent; and (d) be of relatively short duration (typically ≤ 7 days). Realistic goals for phase 0 trials include:replicate preclinical mechanism(s) of action in a human intervention trial;characterize initial pharmacokinetic/pharmacodynamic profiles;evaluate biodistribution patterns, based on imaging technologies. Achieving one or more of these goals in phase 0 trials would permit better selection of active versus inactive compounds for further development. By design, phase 0 trials portend lower risks to human subject than traditional phase I trials. As such, fewer preclinical supporting data are required prior to conducting a phase 0 trial. The initial agent dose depends in part on the stated trial objectives, but should be no greater than 1/50th of the no-observed-adverse-effect level (NOAEL) estimated from animal toxicology testing. Validated pharmacodynamic assays, ideally with low variability in the molecular target, are suitable for application to phase 0 trials if the investigational agent can reasonably be expected to demonstrate target modulation at a non-toxic dose. Standard operating procedures for tissue collection and biospecimen handling should be defined in advance and revised as necessary based on results of the phase 0 trial. Chemoprevention agent development is uniquely challenged by the need to identify widely acceptable, minimally toxic compounds (even when chronically administered) that favorably affect carcinogenesis when measured against surrogate biomarkers, rather than direct cancer endpoints. Methods to identify bioavailable, pharmacodynamically active candidates earlier in the drug development cycle would offer clear advantages with respect to process efficiency, resource utilization and other parameters. Natural products (or derivatives thereof) represent an attractive source for chemoprevention agent discovery and, given their oftentimes demonstrated favorable safety profile at standard doses, provide an excellent opportunity to explore potential benefits gained through the phase 0 trial paradigm. Citation Information: Cancer Prev Res 2010;3(1 Suppl):ED04-02.

Abstract It is estimated that more than 42,000 new cases and 7,780 deaths will be attributed to endometrial cancer (EC) during 2009. Considering the anticipated number of deaths from EC has nearly tripled since 1987 (2,900), a mandate exists to develop new paradigms focusing on prevention, early detection and treatment. Detailed cataloging of the phenotypic, biochemical and genetic signatures of EC will facilitate the maturation of a risk profile for EC thereby affording patients at risk the opportunity for enrollment in prevention or early therapeutic trials. Endometrioid carcinoma (or type I EC) accounts for approximately 80% of endometrial cancers. Epidemiological studies have provided convincing evidence for the pivotal role of obesity in the etiology of this disease. Adiposity induced hyperinsulinemia and hyperestrogenemia are compounding factors and result in physiological alterations that collectively have been reported to facilitate mitogenesis, stimulate neoplastic growth and inhibit apoptosis. The stimulatory effects of estrogen on the endometrium are well characterized. Furthermore, there is increasing evidence that hyperinsulinemia is more directly involved in carcinogenesis. Insulin functions as a growth factor by increasing endometrial insulin receptors thereby enhancing the growth potential of the endometrium to IGFs which are up regulated by estrogens and considered strong mitogens that stimulate cell proliferation and suppress apoptosis. Insulin also inhibits serum and tissue levels of IGFBP thereby increasing the bioavailability of IGF. While the above metabolic abnormalities facilitate incessant proliferative, the evolutionary mechanisms initiating cell transformation from proliferative endometrium to CAH (complex atypical hyperplasia), the precursor lesion, and EC remain unknown. The potential mechanisms include mutations, gene silencing or inactivation of chromatin or a combination of these processes. Microsatellite instability (MSI), reflecting silencing of one or more mismatch repair genes, has been witnessed in approximately 30% of endometrioid EC and 70% of the MSI cohort correlated with methylation of MLH1. Multiple additional major genetic alterations including inactivation of tumor suppressor genes and mutations in oncogenes have been reported. Mutations in PTEN, which antagonizes the PI3K/AKT pathway, have been reported in as high as 83% of EC and 55% of precursor lesions. PTEN mutations are more frequently associated with MSI+ (60–80%) than with MSI- (24–35%) lesions and have a favorable prognosis; patients with PTEN silencing due to promoter methylation have a poorer prognosis. PIK3CA mutations occurring within the catalytic subunit of PI3K constitutively activate AKT and have been detected in 39% of EC but only in 7% of CAH suggesting a later event than PTEN mutations. Mutations in K-ras and β-catenin have been observed in 10–35% of EC resulting in constitutive activation of the MAPK and β-catenin pathways, respectively. The observations that 42–69% of K-ras mutations occur in MSI+ EC and that the majority are G to A transition mutations suggest the silencing of MGMT as a possible etiology. Gene silencing via methylation of gene promoters is a common phenomenon witnessed in nearly all solid tumors. Methylation of cytosine in CpG islands results in the binding domain proteins recruiting histone deacetylases. The subsequent deacetylation and methylation of histone lysine result in tight histone/DNA interactions which impede transcription. While DNMT1 is necessary for maintenance methylation, DNMT3A and 3B are considered responsible for the de novo methylation at the 5-position of cytosine. Several genes have been reported to be silenced via promoter methylation in EC including MLH1, APC (critical component in the β-catenin pathway), PTEN (as noted above), estrogen receptors and progesterone receptors. Several additional cogent tumor suppressor genes or receptors silenced in other hormone responsive tissues such as ovary, breast and prostate and functional in the four major molecular pathways functioning in the endometrium are candidates for promoter CpG methylation. These include MGMT, IGFBP3, RUNX3, and CDKN2A. We have reported varying levels of DNMT mRNA and protein expression in EC tissue specimens and cell culture; DNMT1 and DNMT3B were up regulated in tissues and cell culture while DNMT2 and 3A did not differ significantly from controls. The addition of estrogen to Ishikawa cells (estrogen receptor positive) resulted in an up regulation of DNMT3B. Considering progesterone receptors are absent in many moderate and essentially all poorly differentiated EC, PRB promoter methylation was assessed in Hec-1B and KLE cells before and after treatment with methyltransferase (MT) and histone deacetylase (HDAC) inhibitors alone or in combination. The PRB promoters in both cell lines were methylated prior to treatment with ADC (aza-deoxycytidine), a methyltransferase inhibitor, and became demethylated following exposure to ADC. PR-B mRNA expression in both HEC-1B and KLE cells increased in response to both MT and HDAC inhibitors with a synergistic effect noted with the combination of ADC and TSA. Western blot confirmed the corresponding PR-B protein expression levels. The effect of TSA on DNMT mRNA expression was analyzed in Ishikawa cells. TSA did not significantly alter DNMT1 or -3A mRNA levels but markedly suppressed DNMT3B mRNA expression. RNA decay curves demonstrated rapid degradation of DMNT3B mRNA following TSA treatment of both Ishikawa and AN3 cells. Recent reports have demonstrated a direct interaction of miRNA 29b with the 3′ untranslated regions of both DNMT3A and DNMT3B in lung cancer and acute myeloid leukemia resulting in downregulation of both DNMT3A and DNMT3B. Further studies of the epigenome in endometrial cancer and other solid tumors are required to test the utility of using methylation markers for diagnostic and prognostic purposes and facilitating strategies in the development of epigenetic therapies. Citation Information: Cancer Prev Res 2010;3(1 Suppl):CN02-02.

Abstract Purpose: Celecoxib has been shown to induce cell death in conjunction with its chemopreventive effects. However, the mechanisms by which celecoxib induces cell death are incompletely understood. We determined whether celecoxib can induce autophagy, a process of cell destruction whereby cytoplasmic proteins and organelles are sequestered in vacuoles and delivered to lysosomes for degradation and recycling. Both apoptosis and autophagy have been shown to be negatively regulated by pro-survival Bcl-2 proteins, and the small molecule Bcl-2/Bcl-xL antagonist (ABT-737), can enhance both processes. Since autophagy can be pro-survival or pro-death depending upon the cellular context, we determined whether autophagy inhibition can drive colon cancer cells into apoptosis. Methods: HCT116 (wild-type and Bax−/−), HT29, SW480 colorectal cancer cell lines were treated with celecoxib (0–120 µM) and/or ABT-737 (Abbott; 0–5 µM) in the presence or absence of a pan caspase inhibitor, z-VAD-fmk. Cell viability was determined using the MTS assay and apoptosis was analyzed by Annexin V FITC labeling. Immunoblotting was used to analyze caspase cleavage and LC3 conversion. GFP-LC3B cellular localization was determined by confocol microscopy. Autophagic flux was determined by LC3 immunoblotting in the presence of the lysosome inhibitor, bafilomycin A1. Knockdown of Bcl-xL, Vps34 or Atg8/LC3B were achieved by lentiviral shRNA or siRNA. Results: Celecoxib was shown to induce apoptosis that was attenuated by ectopic Bcl-2 or Bax knockout. ABT-737 synergistically enhanced celecoxib-induced apoptosis as shown by caspase cleavage and Annexin V labeling. Celecoxib also induced autophagy, as shown by conversion of the autophagosome-associated protein light chain 3 (LC3) from a cytosolic (LC3I) to a membrane-bound (LC3II) form as shown by immunoblotting, and a punctate fluorescence pattern of ectopic GFP-LC3 protein. Celecoxib-induced conversion of LC3 that was due to autophagy induction, as shown using the lysosome inhibitor, Bafilomycin A1 that produced an accumulation of LC3II. Furthermore, ABT-737 enhanced LC3 conversion by celecoxib. Autophagy inhibition was achieved using 3-methyladenine (3-MA), wortmannin or knockdown of Vps34 or Atg8/LC3B using siRNA. Inhibition of autophagy enhanced apoptosis as shown by caspase cleavage and Bid truncation in cells treated with celecoxib plus ABT-737. Furthermore, the addition of 3-MA to celecoxib plus ABT-737 produced a 5-fold increase in apoptosis that was associated with caspase cleavage and cytochrome c release. Conclusions: Celecoxib induces both apoptosis and autophagy that can both be potentiated by ABT-737. Inhibition of autophagy was shown to potently drive cells into apoptosis, suggesting a novel therapeutic strategy against colon cancer cells. Citation Information: Cancer Prev Res 2010;3(1 Suppl):B46.

Abstract Purpose: Obesity is associated with an increased risk of colon cancer. However, the influence of body mass index (BMI) upon the outcome of colon cancer survivors and its relationship to gender remains unknown. Experimental Design: BMI (kg/m2) was calculated and categorized in patients with TNM stage II and III colon carcinomas (n= 4,381) enrolled in 7 randomized trials of 5-fluorouracil-based adjuvant chemotherapy. Cox proportional hazards modeling was used to determine the association of BMI with disease-free and overall survival. Results: Among colon cancer patients, 868 (20%) were obese (BMI ≥30 kg/m2) of which 606 were class 1 (BMI 30–34 kg/m2) and 262 were class 2,3 (BMI ≥35 kg/m2). Obese versus normal-weight patients were more likely to be younger, have distal tumors, show intact DNA mismatch repair (MMR), and have increased lymph node metastases (p <0.017). The association of BMI and MMR status was dependent upon patient age (p= 0.031). In a multivariate analysis, BMI was significantly associated with both disease-free (p=0.030) and overall survival (p=0.0017). Men with class 2,3 obesity showed reduced overall survival compared to normal weight men [HR 1.35 (1.02, 1.79); p=0.039]. Women with class I obesity had reduced overall survival [HR 1.24 (1.01, 1.53), p=0.045] compared to normal weight women. BMI was not predictive of therapeutic benefit. Conclusions: Obesity is associated with intact DNA mismatch repair status and was an adverse, independent prognostic variable in colon cancer survivors. Interventions to reduce obesity have the potential to improve patient outcomes in colon cancer survivors. Citation Information: Cancer Prev Res 2010;3(1 Suppl):B111.

Abstract Chromosomal aberrations occur frequently during malignant progression from Barrett's esophagus (BE) to esophageal adenocarcinoma (EAC). In this study, we applied Illumina's 317K high-density SNP arrays to profile chromosomal aberrations at each of the four sequential stages of progression - Barrett's metaplasia (BM), low-grade dysplasia (LGD), high-grade dysplasia (HGD), and EAC. We observed significant trends of increasing LOH/deletion associated with the degree of progression. The average numbers of chromosome arms with LOH/deletion per sample were 0.30, 3.21, 7.70, and 11.90 for BM, LGD, HGD, and EAC, respectively (p-for trend=4.82×10−7). The mean percentages of SNPs with LOH/deletion events were 0.1%, 1.8%, 6.6%, and 17.2% for BM, LGD, HGD, and EAC, respectively (p-for trend=2.64×10−6). In BM, there were scattered chromosome deletions at 3p14.2 (10%), 16q23.1 (5%), and 9p21 (5%), which became predominant aberrations in LGD. More importantly, the 3p14.2 (68.4%) and 16q23.1 (50%) LOH/deletion in LGD was exclusively limited to narrow regions within the FHIT (3p14.2) and WWOX (16q23.1) genes, the two most frequent common fragile sites in the human genome. In contrast, the 9p21 deletion (68.4%) occurred in larger regions (encompassing p16 gene), often involving the whole 9p arm. A significant increase in LOH/deletion of other chromosomes was seen in HGD and there was widespread LOH/deletion across the whole genome in EAC. 17p (47.6%) LOH was the most frequent event in EAC, which mostly spanned the entire 17p arm with only one focal site of LOH at 17p13.1. There were many recurrent small regions of LOH/deletion that disrupted a single gene, most of which are common fragile sites in the human genome. RUNX1 is a potential tumor suppressor gene in EAC. Amplifications were rarer than LOH/deletions. The average numbers of chromosome arms with amplification per sample were 0.30, 0.42, 1.90, and 8.50 for BM, LGD, HGD, and EAC, respectively (p-for trend=1.35×10−9). The mean percentages of SNPs with amplification were 0.5%, 0.4%, 1.5%, and 8.0% for BM, LGD, HGD, and EAC, respectively (p-for trend=1.26×10−8). The most frequent chromosome amplifications in EAC were 8q24.21 (36.6%, MYC), 8p23.1 (31.7%, CTSB), 7q21 (30.8%, CDK6), 20q13.2 (28.6%, ZNF217), and 7p11.2 (25.6%, EGFR). We then analyzed the associations of chromosomal aberrations with clinical features and pathological response in EAC patients treated with neoadjuvant chemoradiation. The number and size of LOH/deletion were significantly associated with pathological response. Non-responders had a greater number (16.4 vs. 8.5, p=0.060) and larger size (662.2 Mb vs. 290.7 Mb, p=0.034) of LOH/deletions, and higher percentage of aberrant SNPs (25.2% vs. 11.2%, p=0.030) than responders. This study provides a genome-wide catalogue of chromosome aberrations occurring during the malignant progression from BE to EAC with the highest resolution to date. Our data support genetic instability and p16 loss as drivers of early neoplastic progression from metaplasia to dysplasia, and p53 aberrations as late events critical for progression to adenocarcinoma. Chromosomal aberrations can predict malignant progression and treatment response in EAC, which may have important clinical implications for cancer prevention and personalized treatment of EAC. Citation Information: Cancer Prev Res 2010;3(1 Suppl):A14.

Abstract Background: Colorectal cancer (CRC) is the third most common incident cancer among women in the United States. Alcohol use has been proposed as a CRC risk factor, but existing observational data remain inconsistent. To date, relatively few studies have examined associations between alcohol use and CRC risk based on molecularly-defined subtypes. Aim: To evaluate associations between alcohol use and incident CRC overall, as well as by molecularly-defined subtypes including microsatellite instability (MSI), CpG island methylator phenotype (CIMP) and BRAF mutation status in the prospective, population-based, Iowa Women's Health Study (IWHS). Methods: The IWHS recruited 41,836 randomly selected Iowa women, ages 55–69 years at enrollment, in 1986. Women with prevalent cancers or no follow-up were excluded, leaving 38,001 eligible for this study. Alcohol use was obtained from a self-administered food frequency questionnaire at study baseline. Incident CRCs were identified through annual linkage with the State Health Registry of Iowa. Archived, paraffin-embedded tissue specimens were recently requested for incident CRC cases diagnosed through December 31, 2002. In the present study, useable tissue specimens were obtained and molecularly characterized for 563/1,255 cases (45%), whose baseline age, body mass index, physical activity level, total energy intake and alcohol use were similar to non-retrieved cases (p > 0.05 for each comparison). Alcohol use was categorized as never (n=21,464), < 3.4 g/day (n=8,313) and > 3.4 g/day (n=8,224), based on the median split among users. Molecularly-defined CRC subtypes were categorized as MSI-high (MSIH; n=148), MSI-low or microsatellite stable (MSI-L/MSS; n=400); CIMP-positive (n=167) or CIMP-negative (n=368); and BRAF-mutation (n=154) or BRAF-wildtype (n=391). Relative risks (RRs) and 95% confidence intervals (95% CIs) were estimated for alcohol use compared to never drinkers, using multivariable Cox regression models adjusted for body mass index, waist-to-hip ratio, smoking status, physical activity level, exogenous estrogen use, and daily intakes of total energy, total fat, red meat, sucrose, calcium, folate, methionine and vitamin E. Results: There was no statistically significant association between alcohol use and overall CRC risk (RR=1.00; 95% CI = 0.86–1.15 for < 3.4 g/day versus none; RR=1.06; 95% CI=0.91–1.24 for >3.4 g/day versus none). Further, there were no associations with alcohol use for specific, molecularly-defined CRC subtypes (RRs shown for > 3.4 g/day versus none): MSI-H (RR=1.07; 95% CI=0.70–1.64); MSI-L or MSS (RR=1.12; 95% CI=0.85–1.47); CIMP-positive (RR=0.97; 95% CI=0.64–1.47); CIMP-negative (RR=1.13; 95% CI=0.85–1.50); BRAF-mutation (RR=0.94; 95% CI=0.61–1.45); and BRAF-wildtype (RR=1.20; 95% CI=0.91–1.57). Conclusion: In this cohort of older women, alcohol use did not appear to be a risk factor for incident CRC, overall or by the defined molecular subtypes. Citation Information: Cancer Prev Res 2010;3(1 Suppl):A115.

Abstract Intermittent caloric restriction (ICR) provides greater prevention of mammary tumor (MT) development than chronic caloric restriction (CCR). Here we assessed the impact of a high-fat diet on this protective effect in relation to serum IGF-I, leptin and adiponectin. At 10 wk of age MMTV-TGF-α female mice were assigned to AL (ad libitum 23% fat calories), ICR (3-wk of 50% caloric restriction with 2× protein, fat, vitamins and minerals followed by 3-wk of 100%AL mice's consumption) and CCR (calorie/nutrient intake matched to ICR for each 6-wk cycle) groups (n=45/group). Food intakes were determined daily. Body weights, MT palpation and MT measurements were done weekly. Mice were followed until MT burden necessitated euthanasia or they reached 79 (end of restriction) or 82 (end of refeeding) weeks of age. Serum samples were obtained at baseline, euthanasia and cycles 5, 8, and 11 during restriction and refeeding for ICR mice. Food intakes for ICR and CCR mice were 24.2% and 24.3% lower than AL mice (p<0.05). Body weights of ICR mice fluctuated in response to their calorie intake resulting in a significant difference among the groups. Final body, mammary and internal fat pad weights of AL mice were heaviest, followed by CCR and ICR-refed mice. ICR-restricted mice weights were the lowest. 66.7% of AL mice developed 1–5 MTs/mouse (grade 1–4). 52.3% of CCR mice had 1–3 MTs/mouse (grade 1–4). Only 4.4% of ICR mice developed 1 MT/mouse (grade 2). ICR-Restricted mice had significantly higher terminal serum IGFBP-3 and lower IGF-I and IGF-1/IGFBP-3 ratio than AL mice. There were no differences for CCR and ICR-Refed mice compared to either AL or ICR-Restricted groups. ICR-Restricted mice had significantly lower serum leptin and significantly higher terminal adiponectin and adiponectin/leptin ratio compared to AL, CCR and ICR-Refed mice. There were no differences in terminal serum measurements between mice with MTs versus those without MTs. IGF-I of AL and CCR mice did not change with age whereas for ICR mice IGF-1 was reduced during restriction periods. AL mice had the highest leptin levels across the study follow by CCR. For ICR mice leptin fluctuated in response to calorie intake, higher in refeeding vs restriction. Adiponectin levels for AL and CCR mice over time were similar. ICR mice had higher adiponectin levels when restricted vs refed. The adiponectin/leptin ratio of AL, CCR and ICR-refed mice was dramatically lower across the study compared with baseline but for ICR-restricted mice it was similar. These results indicate that ICR provides greater protection compared to CCR to prevent MT development even when a high fat diet is fed during refeeding. This was reflected by decreased MT incidence and MT burden and aggressiveness. Serum IGF-I, adiponectin and leptin were significantly affected by periods of 50% restriction providing a milieu conducive to reduced MT development. Citation Information: Cancer Prev Res 2010;3(1 Suppl):A110.

Abstract A substantial body of evidence suggests an association between vascular endothelial growth factor (VEGF) and the neovascularization that occurs with ovarian carcinogenesis. VEGF expression has been directly related to ascites accumulation. Phase II clinical trials in ovarian cancer using single-agent bevacizumab (a monoclonal antibody directed against VEGF) showed promising results, clearly highlighting the importance of anti-angiogenesis based-targeted therapies in ovarian cancer. One of the ways that VEGF mediates angiogenesis is by activating NADPH oxidase-ROS pathway. We have developed and engineered nanoparticles (NP) of cerium oxide (Nanoceria, NCe), a rare earth oxides, which have been tested for their ability to serve as free-radical scavengers to provide protection against chemical, biological, and radiological insults that promote the production of free radicals. Here we show for the first time that treatment of human umbilical vascular endothelial cells (HUVECs) with NCe resulted in inhibition of proliferation, capillary tube formation and VEGF165 induced activation of VEGFR2 and MMP2. Additionally, NCe treatment inhibited growth factor induced migration and invasion of ovarian cancer cells. Collectively, these results indicate that cerium oxide based NP could potentially be used as an antiangiogenic therapeutic agent in ovarian cancer. Citation Information: Cancer Res 2009;69(23 Suppl):C48.