Citations

Abstract Background: The hedgehog pathway is dysregulated in basal cell carcinoma, medulloblastoma, pancreatic, lung, gastric, and a variety of other cancers. BMS-833923 is a potent, oral, small molecule antagonist of hedgehog signaling. Methods: Subjects with advanced or metastatic solid tumors were enrolled into a multiple ascending dose study to identify a maximum tolerated dose and evaluate safety, tolerability, pharmacokinetics (PK), and pharmacodynamics of BMS-833923. All subjects receive a single dose one week prior to continuous daily dosing. The single dose window allows for single dose PK collection for one week. To identify the pharmacologically active dose range surrogate tissue was collected prior to Day 1 and again on Day 22 of the first cycle. Results: As of August 14, 2009 sixteen subjects have been treated at four dose levels: 30 mg (n=5), 60 mg (n=3), 120 mg (n=3), and 240 mg (n=5); with mean patient age of 56 (range 21–78) and ECOG performance 0–1. No subjects in the first three dose cohorts experienced drug-related CTCAE AEs greater than Grade 2. One subject with medulloblastoma in the 30 mg dose cohort continues on study for more than 10 months with stable disease. Treatment of patients in the fourth cohort at 240 mg continuous daily dosing is still on-going. In this cohort one subject experienced drug-related CTCAE Grade 2 lipase elevation and pancreatitis that quickly resolved when drug was withheld. This subject has a diagnosis of Gorlin Syndrome, which is caused by germline mutations in the hedgehog pathway genes Patched or Smoothened. This subject experienced a partial response (PR) that is still ongoing. BMS-833923 PK properties showed dose proportionality between the 30, 60, and 120 mg dose cohorts with a Cmax of 30 ng/ml, 56 ng/ml and 102 ng/ml respectively. The terminal half-life was greater than 7 days and drug accumulations were observed. Conclusion: BMS-833923 is generally well tolerated at daily doses of 30, 60, 120 mg. Citation Information: Mol Cancer Ther 2009;8(12 Suppl):A55.

Abstract It is now widely accepted that a spectrum of somatic alterations occur in human cancer and that particular alterations are associated with response or lack of response to anti-cancer therapies. Here, we undertook a systematic correlation analysis of somatic mutations, copy number aberrations and drug response across 300+ human cancer cell lines. We studied the RAF and VEGFR inhibitor, sorafenib, evaluating associations between sorafenib response and somatic mutations in 35 common cancer genes and high-level amplifications and homozygous deletions in more than 100 minimal common regions of gain and loss, which include many known oncogenes and tumor suppressor genes. Notably, we found that NRAS mutations, among other alterations, were significantly associated with sensitivity to sorafenib (odds ratio = 7, p-value = 0.003), whereas activating BRAF mutations were strongly associated with a lack of response (odds ratio = 4.9, p-value = 0.012). Specifically, 64% (7 of 11) of NRAS mutant cell lines were sensitive to sorafenib, while only 20% (34 of 170) of NRAS wild-type lines were sensitive. On the contrary, just 6.7% (2 of 30) of BRAF mutant lines were sensitive to sorafenib. Because NRAS mutations occur frequently in leukemia and no leukemia cell lines were included in the original analysis, we selected 5 NRAS mutant and 5 NRAS wild-type leukemia cell lines for further evaluation. Consistent with our previous observation, the four most sensitive leukemia cell lines were all NRAS mutant, each line exhibiting greater than 50% growth inhibition after 72 hours of exposure to 4uM sorafenib. These results confirm the original association and suggest that across both solid tumors and hematologic malignancies, NRAS mutations may identify a subset of cancers that are likely to respond sorafenib. In addition, this work demonstrates that systematic analysis of somatic alterations and drug response across a large collection of cancer cell lines is capable of discovering novel predictive biomarkers. Citation Information: Mol Cancer Ther 2009;8(12 Suppl):A47.

Abstract Many cancer researchers are currently generating heterogeneous genomic data sets containing mRNA expression, array based comparative genomic hybridization (aCGH), and other information from multiple patients. In the near future, data sets will likely include proteomics, methylomics, and high throughput sequencing data. Analytical tools that integrate these different data types to prioritize genes for further study have lagged, however. With this in mind, we have implemented a standalone software application that integrates CGH and mRNA expression profiling data. This application implements several different methods to generate ranked lists of genes and genomic regions based on breakpoint frequency, aberration frequency, and the impact of copy number changes on mRNA expression. The software is Java GUI based, with abstracted object models that can be extended as new genomic data types and annotations become available. We used this application to analyze aCGH datasets generated from 22 primary pancreatic tumor xenografts and mRNA expression datasets from 16 of the 22 samples. Genes which were located near a putative breakpoint and whose expression levels were high in a majority of the xenografts samples were considered putative targets. Preliminary IHC analysis of pancreas primary tumor tissue microarrays confirms one of these putative targets, Chemokine (CXC motif) Ligand 5 (CXCL5). By allowing cancer researchers to correlate genomic aberrations with expression data, we believe that this application will generate more meaningful targets for further biomarker identification and/or drug target discovery. Citation Information: Mol Cancer Ther 2009;8(12 Suppl):A30.

Abstract Introduction: The eukaryotic translation initiation factor 5A (eIF5A) is the only known protein to be regulated by post-translational addition of a hypusine residue. Both hypusinated eIF5A and the enzyme that mediates eIF5A hypusination have been identified as markers of neoplastic growth and metastasis. However, recent studies have indicated that, in its unhypusinated form, eIF5A is pro-apoptotic and thus functionally distinct from hypusine-modified eIF5A. In vitro cell studies and in vivo xenograft studies have demonstrated that simultaneous suppression of eIF5A expression and overexpression of a non-hypusinable mutant of eIF5A potently induces apoptosis in multiple cancer cell types. SNS01 is a nanoparticle specifically designed for the treatment of multiple myeloma. SNS01 is comprised of three components: a DNA vector containing a B-cell-specific (B29) promoter driving expression of a pro-apoptotic mutant of eIF5A (eIF5AK50R) that cannot be hypusinated; an siRNA that targets the native hypusinated eIF5A that promotes growth of cancer cells; and a synthetic polymer called polyethylenimine (PEI). Methods: Ethidium-bromide agarose gel electrophoresis was used to detect heparin-mediated release of nucleic acids from nanoparticles. Dynamic light scattering (DLS) was used to assess the short-term stability of SNS01 by monitoring changes in size distribution, polydispersity, and zeta potential. In vitro biological activity of SNS01 was assessed using RT-qPCR to measure eIF5A and eIF5AK50R transgene expression as well as FACS detection of AnnexinV-FITC labeled apoptotic cells. Anti-tumoral activity of SNS01 was evaluated using a subcutaneous human myeloma model (KAS-6/1 cells) in SCID mice with twice-weekly intra-venous injections of SNS01. Results: SNS01 nanoparticles were found to be relatively stable for as long as 48 hours at room temperature with no significant loss in nucleic acid integrity. The nanoparticles had an average diameter of 146.2 nm, a polydispersity of 0.287 and an average zeta potential of 35.3+0.7 mV. These parameters were quite stable over 48 hours. SNS01 could also be frozen at − 80°C for at least one month with no observable loss in biological activity. Twice-weekly intra-venous injections into myeloma tumor-bearing mice of a frozen SNS01 preparation was found to have anti-tumoral activity comparable to freshly prepared SNS01 (frozen SNS01: 89 % tumor inhibition, p = 0.00158; SNS01: 84 % tumor inhibition, p = 0.00003). Conclusions: SNS01 is relatively stable at room temperature and was also found to be stable and biologically active following freezing. Citation Information: Mol Cancer Ther 2009;8(12 Suppl):A196.

Abstract Background and Aims: In patients with Barrett's esophagus (BE), reflux-induced injury promotes esophageal adenocarcinoma, presumably through cyclooxygenase 2 (COX-2) related pathways. Proton pump inhibitors (PPIs) and nonsteroidal anti-inflammatory drugs (NSAIDs) may interrupt reflux-associated carcinogenesis by reducing acid exposure and subsequent inflammation. However, clinical trial data regarding the chemopreventive efficacy of a PPI + NSAID combination are limited. The aim of this multi-center, randomized, phase II trial was to assess the effects of a 28-day intervention with esomeprazole 40 mg bid and aspirin 81 mg qd, 325 mg qd, or placebo qd on tissue prostaglandin E2 (PGE2) concentrations in BE patients. Methods: Using the infrastructure of the Cancer Prevention Network, participants (> 18 years) with histologically confirmed non dysplastic BE were randomly assigned to receive one of three interventions for 28 days: (arm A) esomeprazole 40 mg bid+ aspirin 81 mg placebo qd + aspirin 325 mg placebo qd (n=42); (arm B) esomeprazole 40 mg bid+ aspirin 81 mg qd + aspirin placebo 325 qd (n=63); (arm C) esomeprazole 40 mg bid + aspirin 81 mg qd placebo + aspirin 325 mg qd (n=63). Esophageal biopsies were obtained pre- and post-intervention to assess change in PGE2 concentration as the primary endpoint. Results: In total, 122 participants were randomized, 121 (99%) completed the trial per protocol, and 115 (94%) were evaluated for the primary endpoint. Baseline characteristics were similar across intervention arms. The absolute change (mean + SD) in tissue PGE2 concentration was −67.6 (229.68) in Arm A, −120.9 (281.28) in Arm B (p = 0.10 vs Arm A) and −174.9 (263.62) in Arm C (p = 0.02 vs Arm A). Conclusions: In combination with esomeprazole 40 mg twice per day, aspirin 325 mg per day significantly reduced tissue PGE2 concentration in BE patients after a 28-day intervention, as compared to aspirin placebo. Given the relevance of PGE2 pathways in BE-associated carcinogenesis, further evaluation of this chemoprevention strategy in larger, more definitive phase III trials is warranted. Citation Information: Cancer Prev Res 2011;4(10 Suppl):CN06-03.

Abstract Background: Ingested nitrate can form N-nitroso compounds endogenously, which may lead to DNA adducts and activating mutations in oncogenes. However, previous studies have reported null or inverse associations between dietary nitrate intake and cancer risk, while nitrate intake from drinking water has shown null or positive associations with cancer risk. These associations may be confounded by protective effects of dietary folate, which provides methyl groups for nucleotide synthesis, and thus plays a vital role in the DNA repair system. In a small case-control study, an increased risk of breast cancer was observed among individuals with high dietary nitrate relative to folate intake. We therefore evaluated interaction of total folate with nitrate intake from diet and drinking water on breast cancer risk in the Iowa Women's Health Study (IWHS). Methods: The IWHS is a prospective cohort study of cancer among 41,836 women in Iowa, initiated in 1986. Dietary intake was assessed at study baseline using a food frequency questionnaire (FFQ). Nitrate intake from foods and total folate intake from foods and dietary supplements were computed using consumption frequencies collected by the FFQ. Nitrate intake from drinking water was assessed using a historical analytical database on Iowa municipal water supplies in 15,151 women using municipal water supply. We evaluated the interaction of nitrate and total folate intake with breast cancer risk using Cox proportional hazard regression modeling, adjusting for potential confounders (age, body mass index, waist-hip-ratio, education, smoking, family history of breast cancer, age at menopause, age at first live birth, estrogen use, total energy intake, and intake of vitamin C and E and flavonoids). Results: After baseline exclusions (history of cancer at baseline, previous mastectomy or partial breast resection, implausible energy intake, or ≥30 missing responses on the FFQ), there were 34,388 postmenopausal women in the analytic cohort. Through 2008, 2,875 incident breast cancer cases were identified. Nitrate intake from diet or drinking water was not associated with breast cancer risk. After stratification by total folate intake, high dietary nitrate intake (>106.1 mg/day) was associated with a marginally decreased risk of breast cancer compared to those with low nitrate intake (≤106.1 mg/day) (HR=0.90, 95% confidence interval=0.81–1.00) only among women with folate intake <400 μg/day (p for interaction = 0.65). There was no interaction of nitrate intake from drinking water and total folate intake on breast cancer risk. Conclusions: Our findings do not support the previously reported increased risk of breast cancer risk among individuals with high dietary nitrate and low folate intake. The inverse association between nitrate intake and breast cancer risk observed among women with low folate intake in the present study may be attributed to residual confounding due to high correlation among intakes of nitrate, folate and antioxidants. Citation Information: Cancer Prev Res 2011;4(10 Suppl):A86.

Abstract Short constitutional telomere length has been associated with aging and cancer, but how telomere length is affected by other epidemiologic or environmental variables in health has not been thoroughly studied. Understanding these associations with telomere length in health is important for studies to evaluate the relationship of telomere length and diseases such as cancer. We measured peripheral blood leukocyte DNA telomere length with quantitative PCR in 1977 non-related healthy controls collected through the Colon Cancer Family Registry (an NCI cooperative group) and through the Mayo Biobank and Biobank for Gastrointestinal Health Research, two IRB approved prospective biospecimen collections based at Mayo Clinic, Rochester, MN. The controls were a median age of 50.6 years old, and 49.6% of the controls were male. Ninety-six percent of the controls were white; 1.8% were Asian, and <1% were either black, Pacific Islander, or Native American. Less than 1% of controls were Hispanic. On univariate analysis, as age increased, telomere length decreased (Pearson correlation coefficient = −0.07, 95% CI: −0.11, −0.03). Telomeres were longer in people who consumed more fruits (p<0.01) and vegetables (p<0.01); took aspirin on a regular basis (p<0.01); or had a family history of cancers of any type (p=0.05). Women had longer telomeres than men (p=0.03). Telomeres were shorter in people who consumed alcohol (p<0.01), took folate on a regular basis (p=0.01), or who consumed red meat (p<0.01). Statistical significance was not found in the following variables: tobacco use, diagnosis of diabetes, intake of calcium, use of hormone replacement therapy in women, or body mass index. On multivariate analysis, age, vegetable consumption, family history of colorectal cancer or any type of cancer, and folate intake were identified as being significantly associated with telomere length. Telomere length may be associated with multiple environmental and demographic variables in healthy individuals, and adjusting for these may be important for studies that test for an association between telomere length and diseases such as cancer. Citation Information: Cancer Prev Res 2011;4(10 Suppl):A82.

Abstract Background: Colorectal cancer (CRC) is the second leading cause of cancer deaths in the United States, yet it is potentially the most treatable and preventable cancer with effective screening. Exact Sciences has developed a multi-biomarker CRC screening test that targets DNA methylation, DNA mutations, and hemoglobin in stool. The aim of this study was to evaluate the analytical accuracy of a novel assay for the detection of KRAS mutation sequences at Codons 12 and 13 in well-characterized colorectal tissues. Methodology: A multiplexed KRAS assay was designed utilizing QuARTS (Quantitative Allele-specific Real-time Target and Signal amplification), a highly sensitive technology that combines allele-specific DNA amplification with invasive cleavage chemistry to generate signal during each amplification cycle similar to real-time PCR. The assay, which detects seven KRAS mutations and the reference gene β-actin, was used to assess 87 colorectal tissue samples (52 CRCs, 16 adenomas ≥ 1cm, and 19 normal epithelia) as determined by Mayo Clinic Pathology. Samples were obtained by microdissection of fresh frozen tissue biopsies. DNA was extracted by Mayo Clinic using a standardized chloroform/phenol methodology. The genotypes of each sample were established using dye terminator dideoxy sequencing in both the forward and reverse orientations. Copy numbers of KRAS mutations and β-actin were determined by conventional comparison against standard curves. KRAS data are reported as percent mutation and calculated by dividing mutant copies by β-actin copies and multiplying by 100. Results: Based on sequencing data: the 52 CRC samples contained 22 KRAS mutations and 30 wild-type genotypes, the 16 adenomas ≥ 1cm contained 8 mutations and 8 wild-type genotypes, and the 19 normal tissues contained all wild-type genotypes. The QuARTS assay detected 100% of the KRAS mutations in the CRC and adenomas and provided excellent differentiation between wild-type and mutation, with the highest percent KRAS mutation of normal wild-type samples at 0.55% and the lowest percent mutation of KRAS positive samples at 8.34%. Based on this data, this assay has the potential to be more sensitive analytically than standard sequencing. Conclusion: The QuARTS assay detects KRAS mutations in tissue with high sensitivity and specificity. This assay method could provide an accurate and high throughput approach to detection of KRAS mutations in biospecimens for multiple clinical applications. Citation Information: Cancer Prev Res 2011;4(10 Suppl):A22.