Citations

Abstract Objective. Molecularly distinct PCNSL signatures with divergent clinical behavior are now recognized. Implied within this heterogeneity are mechanisms for treatment response and pattern of failure. Recent cytogenetic and genomic studies demonstrated influences of select chromosomal regions on outcome to treatment and survival. These included genetic and epigenetic alterations affecting CDKN2A (9p21.3) that distinguished PCNSL from its systemic counterpart. We now report that deletion of 9p21.3/p16 is associated with a negative effect on survival. Methods and Patients. Well-annotated and population-based formalin fixed paraffin embedded (FFPE) patient samples were sourced from the SEER TRP. Specimens were retrieved from the Hawaii, Iowa and Los Angeles County (LA Co) tissue repositories. “Home Brew” fluorescent in situ hybridization (FISH) probes for BCL6, and ptpr-α were prepared according to a standard protocol (Cady et al. J Clin Oncol 2008;26:4814-9). FISH probes for 9p.21 were prepared similarly and then compared to a commercially available probe. Survival was based on the SEER TRP clinical annotations. Results. Thirty five patients were sourced - twelve from Iowa, 13 from Hawaii, and 10 from LA County. The test cohort was 23 from Iowa and Hawaii; the FISH probe failed in 9 and three had insufficient remaining tumor for analysis. For the Iowa and Hawaii registries and for the registries combined the lack of FISH probe detection of 9p.21/p16 correlated with survival (p=0.0159) and was independent of BCL6 (p=0.8788) and ptpr-α (p=0.3724). Conclusion. Deletion of p16 confers a negative effect on survival of PCNSL patients and appears to be independent of treatment, age, BCL6 and ptpr-α status. These results need to be confirmed in a larger sample size. 9p21.3 detection by FISH in feasible in surgical specimens and may aid in the stratification of such patients into different and/or more intensive treatment regimens. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 4507. doi:1538-7445.AM2012-4507

Abstract Background: Despite recent advances in prevention and therapy, colorectal cancer (CRC) continues to account for nearly 50,000 deaths per year in the US. TNM stage is the current CRC prognostic standard, yet within-stage prognostic heterogeneity is well documented. Microsatellite instability (MSI), CpG island methylation phenotype (CIMP), and BRAF- and KRAS-mutation status represent candidate prognostic markers. However, associations between these markers and CRC survival have not been described in a population-based setting. Methods: Data and tissue resources were obtained from the Iowa Women's Health Study (IWHS), which recruited 41,836 women, ages 55-69 years, at study entry (1986). Incident CRC cases were ascertained by annual linkage with the Iowa Cancer Registry. Archived, paraffin-embedded tissue specimens were collected from 732 representative CRC cases diagnosed through 12/31/2002. Established laboratory methods were used to characterize CRC cases: MSI-H or MSS/MSI-L (by instability in β3 vs. <3 out of 10 markers, respectively); CIMP+ or CIMP− (by promoter hypermethylation in β3 vs. 0-2 out of 5 genes, respectively); BRAFwt or BRAFmut (by fluorescent allele specific PCR to detect the V600E point mutation in exon 15); and KRASwt or KRASmut (by direct sequence analysis of codons 12 and 13 in exon 2). Cox regression models were fit to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for time to death of any cause adjusted for age, stage, grade, and treatment status. Results: CRC cases with informative molecular marker data ranged from 515/732 (70%) for KRAS to 548/732 (75%) for MSI status. Mean follow-up was 4.4 years for deceased individuals and 11.2 years for women alive at last contact. After multivariable adjustment, both MSS/MSI-L (p=0.004) and KRASmut (p=0.048) tumors were associated with poorer survival. Survival did not significantly differ across levels of CIMP and BRAF status. Conclusions: MSI and KRAS status may influence CRC survival among older women. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 4492. doi:1538-7445.AM2012-4492

Abstract Biomarkers are lacking for identifying the switch of transforming growth factor-beta (TGF-β) from tumor-suppressing to tumor-promoting. Mutated p53 (mp53) has been suggested to switch TGF-β to a tumor promoter. However, we found that mp53 does not always promote the oncogenic role of TGF-β. Here, we show that endogenous mp53 knockdown enhanced cell migration and phosphorylation of ERK in DU145 prostate cancer cells. Further, ectopic expression of mp53 in p53-null PC-3 prostate cancer cells enhanced Smad-dependent signaling, but inhibited TGF-β-induced cell migration by downregulating activated ERK. Reactivation of ERK by the expression of its activator, MEK-1, restored TGF-β-induced cell migration. Since TGF-β is known to activate MAPK/ERK pathway through direct phosphorylation of adaptor protein ShcA and MAPK/ERK signaling is pivotal to tumor progression, we investigated whether ShcA contributed to mp53-induced ERK inhibition and the conversion of TGF-β's role during carcinogenesis. We found that mp53 expression led to decrease of phosphorylated p52ShcA/ERK levels and increase of phosphorylated Smad levels in a panel of mp53-expressing cancer cell lines, and in mammary glands and tumors from mp53 knock-in mice. By manipulating ShcA levels to regulate ERK and Smad signaling in human untransformed and cancer cell lines, we show that TGF-β's role in regulating anchorage-dependent and -independent growth, and migration, can be shifted between growth suppression and migration promotion. Thus, our results, for the first time, suggest that mp53 disrupts ShcA's role in balancing Smad-dependent and -independent signaling activity of TGF-β and that ShcA/ERK signaling is a major pathway regulating the tumor-promoting activity of TGF-β. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1069. doi:1538-7445.AM2012-1069

Abstract Cholangiocarcinomas are rare but aggressive cancers, with an increasing incidence and a dismal 5-year survival rate of less than 5%. Mutations in the genes encoding isocitrate dehydrogenase, IDH1 and IDH2, have been reported in ∼70% of gliomas, ∼20% of myeloid leukemias, ∼56% of chondrosarcomas, and ∼10% of melanomas. We discovered IDH1 and IDH2 mutations in 29 of 305 (9%) intrahepatic cholangiocarcinomas. Tumors with mutations in IDH1 or IDH2 had lower 5-hydroxymethylcytosine and higher 5-methylcytosine levels, as well as increased dimethylation of histone H3K79. Mutations in IDH1 or IDH2 were independently associated with longer time to recurrence of cholangiocarcinoma in multivariate analysis (p = 0.046). We identified 2,267 genes that were significantly hypermethylated in tumors with mutations in IDH1 or IDH2. Hypermethylated CpG sites were significantly enriched in CpG shores and in the 1500 bp upstream of annotated transcription start sites, suggesting a global regulation of transcriptional potential. Gene expression profiling of 7 IDH1/2-mutant and 20 IDH1/2-wildtype tumors revealed increased expression of citric acid cycle and oxidative phosphorylation enzymes, as well as decreased expression of cytoskeleton organization genes. Integrated analyses of DNA methylation and gene expression identified interleukin-6 and several of its downstream targets as candidates for silencing by DNA methylation. Conclusions: Cholangiocarcinomas with mutations in IDH1 or IDH2 represent a molecular subclass with distinct signaling pathway alterations. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1058. doi:1538-7445.AM2012-1058

Abstract Adrenocortical carcinoma (ACC) is an aggressive cancer with a 5-year survival rate of 20-30%. Mitotane is the only approved drug for the treatment of patients with ACC. It often carries significant toxicities which result in the discontinuation of treatment. There are no approved second line therapies. The increased incidence of ACC in the cancer predisposition syndrome, Li-Fraumeni, suggests the involvement of the p53 pathway in ACC pathogenesis. Our analysis of the gene expression profiles of 19 ACC samples identified dysregulation of the G2/M transition and the activity of the p53 modulator, MDM2 as important in ACC pathogenesis. Polo-like kinase-1 (PLK1) is involved in the G2/M transition and acts to promote MDM2 activity through its phosphorylation. We observed that PLK1 inhibition by siRNA results in up to a 70% reduction in viability in the ACC cell lines SW-13 and H295R. Therefore, we studied PLK1 inhibition as a potential therapeutic strategy. We used the small molecule inhibitor, BI-2536, to inhibit PLK1 function in SW-13 and H295R. Drug-dose response curves demonstrated that both cell lines are sensitive to pharmacological inhibition of PLK1 (IC50 doses of 0.0094815 μM and 0.062805 μM for SW-13 and H295R, respectively.) Murine xenograft studies demonstrated that BI-2536 resulted in a statistically significant reduction in tumor growth in SW-13 but not H295R. Examination of p53 protein levels in the presence of the drug showed a dose-dependent reduction in p53 levels in SW-13, which carries a homozygous p53 mutation. The same was not true in H295R, which is p53 wild-type. To test the hypothesis that BI-2536 was decreasing mutant p53 levels by promoting its proteasomal degradation, both cell lines were treated with previously determined inhibitory concentrations of BI-2536, either alone or in combination with the proteasome inhibitor, MG132. Western blot analysis showed recovery of p53 protein when cells were concomitantly treated with MG132, supporting a role for BI-2536 as a regulator of proteasomal degradation. Both ACC cell lines are relatively insensitive to MDM2 inhibition by nutlin-3 (NCI60 GI50 values range from ∼4 uM to ∼2 uM versus ACC cell lines @13-15uM), possibly because PLK1 stimulates MDM2 and renders nutlin-3 ineffective. We therefore assessed the ability of BI-2536 to sensitize ACC cell lines to the effects of the MDM2 inhibitor. BI-2636 did show synergy with nutlin-3, shifting the IC50 in SW-13 from 19.78 μM to 6.45 μM and from 12.75 μM to 2.84 μM in H295R. These results demonstrate that inhibition of PLK1 alone or in combination with an MDM2 inhibitor warrants further investigation as a treatment for patients with ACC. Cells with mutant p53 are more sensitive to the growth inhibitory effects of BI-2536. In the context of wild-type p53, the combined inhibition of both PLK1 and MDM2 results in loss of viability. Further clinical development of PLK1 as a target should take p53 mutation status into account. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 978. doi:1538-7445.AM2012-978

Abstract Objective The prevalence and mortality for head and neck cancer (HNC) has not improved significantly in the last several decades. It is the sixth most common cancer with an estimated 600,000 new cases diagnosed worldwide every year and has ∼50% 5-year survival rate. Of these, 47000 new cases are diagnosed in the US annually. The most common risk factors for HNC are tobacco and alcohol use but a growing subset is also attributed to human papillomavirus (HPV) infection. Late stage HNCs are treated with a combination of surgery, radiation, and chemotherapy (often platinum-based), but the cancers treated with platinum-based chemotherapy often develop drug resistance. Identification of target genes using high-throughput RNAi (HT-RNAi) gene-silencing technology has become an increasingly popular method in the field of cancer research. The objective of our study is to use this functional genomics based approach to identify genes that, when silenced, increase the sensitivity of the platinum drugs. This would possibly help us in identifying potentiators of platinum-based drugs to more effectively treat HNC patients. Methods We performed drug dose response (DDR) experiments on nine HNC cell lines; including two are HPV-positive lines, to identify cisplatin-resistant and -sensitive cancer cell lines. To identify sensitizers of cisplatin response, we used a siRNA library targeting 572 kinases. Each kinase is represented by two different siRNA sequences in the library. Based on the data mined from published literature on head and neck cancer as well as genes thought to confer a functional relationship between HPV infection and HNC, a more focused siRNA library was also designed and included in the screening. Cell lines were reverse transfected with the siRNAs in a 384 well format, dosed with cisplatin after 24 hours and the plates were read 72 hours later. Results We calculated the inhibitory concentrations using DDR experiments for all the nine HNC cell lines and identified cisplatin-resistant (UMSCC47 and SCC9) and -sensitive (Cal27, UMSCC14C, and SCC090) HNC cell lines. HT-RNAi experiments have been performed on the cisplatin-resistant cell lines, one of which is HPV-positive. After data analysis, confirmation of silencing and validation of drug modulation will be done on a subset of candidate genes. Conclusions HNC patients with surgically non-resectable tumors could have improved treatment with chemotherapeutic drugs; however, acquired drug resistance often inhibits a successful treatment. Identification of sensitizing targets may provide hope for a better outcome, but may also allow for use of smaller doses of more toxic drugs, such as cisplatin. In addition, this study may also identify alternate genes that can be targeted in the subset of HPV-positive HNC. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 5136. doi:1538-7445.AM2012-5136

Abstract Human Sulfatase1 enzyme (HSulf-1) is down-regulated in a majority of ovarian cancer cell lines and primary tumors, but the functional consequence of this downregulation remains unclear. Here, we show that down-regulation of HSulf-1 by RNA interference resulted in an elevated level of phosphorylated Erk and phosphorqylated Akt as well as decreased Bim level in OV202 ovarian cancer cells. Treatment with PD98059 (p-Erk inhibitor) but not LY90024 (PI3K inhibitor) resulted in increased Bim level in Hsulf-1 knockdown cells, suggesting that increased Erk pathway plays a more important role in modulating Bim level after loss of HSulf-1. Consistently, the results of real-time PCR confirmed that there was no significant change in the mRNA level of Bim after knockdown of HSulf-1 expression. When treated with CDDP, OV202 cells with knockdown of HSulf-1 displayed more resistance to drug-induced apoptosis, with IC50 value 3-fold higher than cells with non-targeting shRNA (NTC), while SKOV3 cells with overexpression of HSulf-1 were more sensitive to CDDP-induced apoptosis compared to the control cells. Moreover, HSulf-1 downregulated OV202 cells showed remarkable growth of colonies in soft agar compared to no colony growing with NTC cells. When injected subcutaneously, HSulf-1 ShRNA clones but not NTC cells formed xenogrfts in nude mice. Importantly, rescuing Bim expression in HSulf-1 shRNA cells not only endowed cells sensitivity to CDDP treatment, but also significantly decreased numbers of colony formation in soft agar and significantly retarded tumor growth in nude mice. Collectively, these results strongly suggest that down-regulation of HSulf-1 promotes chemoresistance and tumorigenicity in ovarian cancer cells through post-translational downregulation of Bim level. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 4179. doi:1538-7445.AM2012-4179

Background Evaluating recombinant tissue plasminogen activator utilization rates is important, as many studies have demonstrated that administration of recombinant tissue plasminogen activator to qualified patients significantly improves prognosis. Aims We investigated recent trends in the utilization and outcomes of administration of intravenous recombinant tissue plasminogen activator in the United States using the National Inpatient Sample between 2001 and 2008. Methods We identified patients with a primary diagnosis of acute ischemic stroke who underwent treatment with intravenous recombinant tissue plasminogen activator and studied utilization rates and clinical outcomes: discharge to long-term facility (morbidity), in-hospital death (mortality), and intracranial hemorrhage. Information on demographics, hospital characteristics, and comorbidities was collected. A multivariate logistic regression analysis was performed to determine independent predictors of morbidity, mortality, and intracranial hemorrhage. Results Intravenous recombinant tissue plasminogen activator utilization increased from 1·3% in 2001 to 3·5% in 2008. On multivariate analysis, variables associated with increased morbidity after intravenous recombinant tissue plasminogen activator administration included advanced age ( P < 0·001), female gender ( P < 0·001), and comorbidities of atrial fibrillation ( P < 0·001) and hypertension ( P < 0·001). Increased mortality was associated with increased age ( P < 0·001) and comorbidities of atrial fibrillation, congestive heart failure, coronary artery disease, and diabetes ( P < 0·001 for all comorbidities). Conclusions Intravenous recombinant tissue plasminogen activator utilization rates increased between 2001 and 2008. Advanced age and atrial fibrillation were significantly associated with increased morbidity and mortality among patients treated with intravenous recombinant tissue plasminogen activator.

A candidate vaccine against Nipah and Hendra viruses, recently emerging zoonotic threats, looks promising.