Citations

Abstract Introduction: CX-4945 is a first-in-class, orally administered small molecule that potently and selectively inhibits protein kinase CK2, a previously unexploited molecular target with well documented roles in many cancers. In vitro, CX-4945 selectively kills cancer cells by modulating key survival pathways, resulting in cell cycle arrest, inhibition of cell proliferation, and promotion of apoptosis. CK2 hyperactivation of the PI3K/Akt pathway promotes the phosphorylation of several proteins which we have exploited as biomarkers for CX-4945 activity. A validated laser scanning cytometry method has been developed to quantify the phosphorylation of p21 and Akt in cells, and this has been employed to characterize these substrates in circulating blood cells collected from patients in the phase I clinical trial of CX-4945. Procedures: Eligible patients with advanced solid tumors with progressive disease, or for whom there are no available standard therapies, were administered CX-4945 in successive dose cohorts using a standard 3×3 design at: 90, 160, 300, 460, and 700 mg per dose. Oral doses were administered twice daily for twenty-one consecutive days of a four week cycle. Serial plasma samples were collected for pharmacokinetic analysis on the first and final dosing days of Cycle 1 (i.e., Day 1 and Day 21). In addition, whole blood samples were collected at pre-treatment, 4 hours and 8 hours following the first dose of CX-4945 on Day 1 and Day 21, and peripheral blood mononuclear cells (PBMCs) were isolated for pharmacodynamic biomarker evaluations (specifically, total and phosphorylated forms of p21 and Akt). Plasma samples were also collected at these time points for quantification of plasma IL-6. Results: Seventeen patients with advanced solid tumors from five separate dose cohorts have received oral doses of CX-4945 to date, and all patients in the study participated in the collection of PBMCs. Biomarkers from patients in Cohorts 3 and 4 demonstrated changes in their profile consistent with the inhibition of CK2. CX-4945 displays general linearity in PK parameters between the dose cohorts, with a terminal half life of approximately 25 hours at steady state. Conclusions: To date, no DLTs have yet been observed, and the MTD remains to be defined in this Phase I study. Early signals suggest a modulation of the biomarker profile consistent with CK2 inhibition. Patient enrollment will continue, to further characterize CX-4945's safety, tolerance, pharmacokinetics and pharmacodynamic effects. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2763.

Abstract Recent GWAS have identified and confirmed associations between several SNPs in the gene desert located on chromosome 8q24 with risk of cancers of the breast, prostate, glioma, bladder and colorectum. Evidence supporting an association with ovarian cancer is limited and inconsistent. Here we evaluate preliminary results in the 8q24 region from stage I of an ongoing invasive epithelial ovarian cancer GWAS among 1864 cases (1096 serous cases) and 1912 controls. All subjects were self-reported non-Hispanic non-Jewish Caucasian, and were genotyped with the Illumina 610quad Chip. Samples and SNPs with call rates less than 95% were excluded (9.6% and 9.9%, respectively) as well as 128 subjects with ambiguous gender, unresolved identical genotypes and less than 80% European ancestry were also excluded. Our most significant hit in the region was rs6651252 located at 8q24.21 with p = 0.000125 for all ovarian cancer, and 1.02*10−5 for serous cases only. This region is located approximately 849 kb downstream of the previous 8q24.21 findings on other cancers, and was not in linkage disequilibrium with any of the haplotype blocks reported previously. We further examined the block structure of this region with eight genotyped SNPs located within 129.61 to 129.64 MB (rs10088218, rs1516973, rs1516975, rs16903097, rs10098821, rs6651252, rs1561928, and rs1561927) and performed haplotype analysis to evaluate the association with ovarian cancer risk. One haplotype (AAGCAGGG, estimated frequency=0.11) was significantly associated with decreased ovarian cancer risk with an odds ratio of 0.67 (all cases, 95% CI: 0.78-0.91, p=0.0026, empirical p= 0.0020). This region contains no known genes, but it is located upstream and overlaps with a known copy number variation (CNV) reported by Redon et al. (2006). Previous published literature on array CGH and CNV results from TCGA (The Cancer Genome Atlas) also indicate that the 8q24.21 region is associated with frequent gains/amplification in ovarian tumors. Combined analysis of SNPs and CNV identified in this region is underway to elucidate the joint effect of these two types of genetic variation on ovarian cancer risk. Our result indicates a novel locus on 8q24.21 is associated with epithelial ovarian cancer susceptibility. Haplotype analysis reveals one specific haplotype that is associated with decreased ovarian cancer risk compared to the most common haplotype. Given previous 8q24 findings from other cancers and evidence from publicly available resources, fine-mapping and resequencing of this region is warranted. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4724.

Abstract The nonsteroid antiestrogen tamoxifen [trans-1-(4-b-dimethylaminoethoxyphenyl)-1,2-diphenylbut-1-ene] is the most commonly used endocrine treatment for estrogen receptor α (ERα)-positive breast cancer in pre- and post-menopausal women, and it has helped to reduce breast cancer death rate by one third. Tamoxifen is extensively metabolized, and several metabolites have been detected in human serum. It is metabolized to 4-hydroxytamoxifen and N-desmethyltamoxifen by the action of CYP2D6 and CYP3A4/5 enzymes, respectively. N-desmethyltamoxifen and 4-hydroxy-tamoxifen are further converted to endoxifen by the action of these enzymes. Steady state levels of serum tamoxifen/metabolite are achieved within 4 weeks of continuous administration of the drug. The therapeutic efficacy of tamoxifen is determined by the distribution of the drug into tissues and the availability of the parent drug and its active metabolites in target tissues. Recent reports indicate that endoxifen might act as an antiestrogen. In order to examine the mechanism of action of endoxifen on an ERα-positive breast cancer cell line, MCF-7, we determined the effects of 100, 250, 500 and 1000 nM concentrations of this agent on cell growth, c-myc oncogene expression and activity of the polyamine biosynthetic enzymes. MCF-7 breast cancer cells were treated for 1, 3 or 5 days with endoxifen. Endoxifen had a growth inhibitory effect on MCF-7 cells by day 3 and 5 of treatment, as measured by cell number. Estradiol increased cell number by >2-fold compared to untreated control by day 5 of treatment, whereas endoxifen inhibited the estrogenic effect. c-myc gene expression was increased by a significant 2- to 3-fold by 4 nM estradiol in 2 and 4 hours of treatment, while 250 and 500 nM endoxifen suppressed the increase in c-myc gene expression, as measured by real-time qPCR experiment. In the absence of estradiol, endoxifen slightly (1.5 fold) increased c-myc gene expression. Endoxifen decreased ornithine decarboxylase (ODC) and S-adenosine methyl decarboxylase (AdoMetDC) activities in a concentration- and time-dependent manner; however, it had little effect on spermidine/spermine N1-acetyl transferase (SSAT) activity. The change in biosynthetic enzyme activities were reflected in polyamine pools, as decreased putrescine and spermidine levels. There were no changes in spermine level. As expected, treatment of the cells with 4 nM estradiol induced ODC and AdoMetDC activities, and slightly decreased SSAT activity. Addition of endoxifen in combination with 4 nM estradiol led to even more dramatic decrease in ODC and AdoMetDC activities and reduction of putrescine and spermidine levels. These results support our hypothesis that endoxifen can act as an antiestrogen and suppress cell growth stimulatory effects of estradiol in ERα-positive breast cancer cells. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4603.

Abstract There is increasing evidence that neighboring stromal cells are not uninvolved bystanders in the pathway to cancer. We hypothesized that SNPs in genes expressed as a consequence of interactions between ovarian cancer cells and the host micro-environment could contribute to ovarian cancer susceptibility. We therefore used a two-stage approach to comprehensively evaluate common single nucleotide polymorphisms (SNPs) in the Ovarian Cancer Association Consortium (OCAC) for 173 genes involved in stromal-epithelial interactions. Cases with epithelial ovarian cancer (n=675) and controls (n=1,162) were genotyped at 1536 SNPs using an Illumina GoldenGate™ BeadArray array. Logistic regression was used to estimate odds ratios (ORs) and adjust for potential confounders. Based on Positive Predictive Value estimates, three SNPs - PODXL rs1013368, ITGA6 rs13027811 and MMP3 rs522616 - were selected for replication using TaqMan genotyping in 3,734 serous invasive cases and 10,067 controls from 16 OCAC case-control studies. An additional 18 SNPs with Pper-allele <0.05 in the test set, and which fitted into an iPLEX design, were selected for replication by a subset of five OCAC studies (n=1771 serous invasive cases; n=4022 controls). The associations observed in the test set for the PODXL, ITGA6 and MMP3 SNPs were completely attenuated in the replication set (adj. Pper-allele ≥0.5). However, TERT rs7726159 showed evidence of a log additive association with ovarian cancer risk in the replication study (Pper-allele =0.03). Combined analysis of the test and replication sets for this SNP showed a significant association with risk of serous ovarian cancer among non-Hispanic whites [adj. ORper-allele 1.14 (1.04 - 1.24) p = 0.003]. A stronger association was observed for serous invasive cases when data for all ethnicities were included [adj. ORper-allele 1.18 (1.09 - 1.28) p = 2.46 × 10−5]. Stratification by histological subtype and malignant potential showed that TERT rs7726159 was also associated with risk of serous borderline tumors, but not with any other subtypes. Although TERT variants have not been previously reported to be associated with ovarian cancer, multiple genome-wide association studies have reported associations with this locus and risk of glioma, basal cell carcinoma, and several cancer types that are known to originate in the epithelium, including lung, bladder, prostate and cervical cancer. Further analysis of this locus is necessary to definitively identify the causal SNP(s). Our study adds to the growing evidence that, as well as 8q24, the TERT locus at 5p15.33, is a general cancer susceptibility locus. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4727.

Object Glial scar and cystic formation greatly contribute to the inhibition of axonal regeneration after spinal cord injury (SCI). Attempts to promote axonal regeneration are extremely challenging in this type of hostile environment. The objective of this study was to examine the surgical methods that may be used to assess the factors that influence the level of scar and cystic formation in SCI. Methods In the first part of this study, a complete transection was performed at vertebral level T9–10 in adult female Sprague-Dawley rats. The dura mater was either left open (control group) or was closed using sutures or hyaluronic acid. In the second part of the study, complete or subpial transection was performed, with the same dural closure technique applied to both groups. Histological analysis of longitudinal sections of the spinal cord was performed, and the percentage of scar and cyst formation was determined. Results Dural closure using sutures resulted in significantly less glial scar formation (p = 0.0248), while incorporation of the subpial transection surgical technique was then shown to significantly decrease cyst formation (p < 0.0001). Conclusions In this study, the authors demonstrated the importance of the vasculature in cyst formation after spinal cord trauma and confirmed the importance of dural closure in reducing glial scar formation.

Purpose Findings from the human epidermal growth factor receptor 2 (HER2) –positive National Surgical Adjuvant Breast and Bowel Project (NSABP) B31 trial suggested that MYC/HER2 coamplification (> 5.0 copies/nucleus) was associated with additional benefit from adjuvant trastuzumab in patients with early-stage breast cancer. To further explore this relationship, we investigated associations between MYC amplification and disease-free survival (DFS) in a similar adjuvant trastuzumab HER2-positive breast cancer trial—North Central Cancer Treatment Group (NCCTG) N9831. Patients and Methods This analysis included 799 patients randomly assigned to receive chemotherapy alone or with concurrent trastuzumab on N9831. Fluorescence in situ hybridization (FISH) was performed by using a dual-probe mixture for MYC and centromere 8 (MYC:CEP8) on tissue microarrays. MYC amplification was prespecified as MYC:CEP8 ratio > 2.2 or average MYC copies/nucleus > 5.0. Exploratory variables included polysomy 8. Results In comparing DFS (median follow-up, 4.0 years) between treatments, patients with MYC:CEP8 ratio ≤ 2.2 (n = 618; 77%) and > 2.2 (n = 181; 23%) had hazard ratios (HRs) of 0.46 (P < .001) and 0.67 (P = .33), respectively (interaction P = .38). Patients with MYC copies/nucleus ≤ 5.0 (n = 534; 67%) and > 5.0 (n = 265; 33%) had HRs of 0.52 (P = .002) and 0.48 (P = .02), respectively (interaction P = .94). Patients with MYC:CEP8 ratio < 1.3 with normal chromosome 8 copy number (n = 141; 18%) and ≥ 1.3 or < 1.3 with polysomy 8 (n = 658; 82%) had HRs of 0.66 (P = .28) and 0.44 (P < .001), respectively (interaction P = .23). Patients with MYC copies/nucleus < 2.5 (n = 130; 16%) and ≥ 2.5 (n = 669; 84%) had HRs of 1.07 (P = .87) and 0.42 (P < .001), respectively (interaction P = .05). Conclusion We did not confirm the B31 association between MYC amplification and additional trastuzumab benefit. Exploratory analyses revealed potential associations between alternative MYC/chromosome 8 copy number alterations and differential benefit of adjuvant trastuzumab.