Citations

Abstract Background The role of estrogen receptor alpha (ERα) in breast cancer has been studied extensively; yet, much less is known about full-length ERβ (ERβ1) and even less about its 4 variant forms (ERβ2-5). We have recently implicated a role for ERβ1 in sensitizing ERα expressing breast cancer cells to anti-estrogens. However, the ability of ERβ2-5 to modulate ERα and ERβ1 activity, and their association with cancer development, progression, and response to estradiol (E2) and anti-estrogens are not well understood. Here, we provide evidence that the presence of ERβ variants may be of diagnostic and clinical relevance for breast cancer patients and describe the development and characterization of a novel, highly specific monoclonal antibody (MC10) that is able to detect their expression in tumor biopsies. Methods: Transient transfection and luciferase assays were used to determine the transcriptional activity of ERβ2-5 in response to E2 and anti-estrogens alone or in combination with ERα and ERβ1. A novel monoclonal antibody targeting all ERβ variants (MC10) was developed and characterized. The sub-cellular localization of ERβ2-5 was determined via confocal microscopy. Finally, the MC10 antibody was used to assess ERβ positivity in breast tumors and was compared to that of another monoclonal antibody which only detects ERβ1. Results: Unlike ERβ1, ERβ2-5 do not activate an estrogen response element (ERE) in response to E2 and instead, slightly repress the activity of this reporter construct. Expression of ERβ2-5 does not significantly alter the transcriptional activity of ERβ1 following E2 treatment. However, ERβ2, 3 and 5, but not ERβ4, significantly enhance the E2-induced transcriptional activity of ERα. Interestingly, expression of ERβ3, 4 and 5, but not ERβ2, enhance the ability of anti-estrogens to block ERα mediated transcriptional activity. Confocal microscopy revealed that ERβ1 and 2 are almost exclusively localized to the cell nucleus. However, ERβ3-5 exhibit significant cytoplasmic and peri-nuclear localization. Immunohistochemistry of breast cancer biopsies using the MC10 antibody revealed multiple staining patterns including tumors which exhibit primarily nuclear staining and others primarily cytoplasmic, both in the presence and absence of ERα. These results are in contrast to the almost exclusive nuclear staining obtained on the same tumors with an ERβ1-specific antibody. Conclusions: ERβ variants exhibit variable sub-cellular localization patterns and can influence the function of ERα, both in response to E2 and anti-estrogens. Therefore, the differential expression of ERβ variants and their cellular localization may influence breast cancer progression and/or therapeutic responses. The use of ERβ antibodies which do not detect all ERβ variants, or the use of a single ERβ antibody which does not discriminate between ERβ1 and its variants, is unlikely to reveal the complete biological significance of total ERβ expression in breast cancer and may in part explain the conflicting studies which have been reported for ERβ in the field. Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P4-02-03.

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.

Background— The objective of the present study was to investigate the effect of cardiac resynchronization therapy (CRT) on cardiac autonomic function. Methods and Results— This prospective study included 45 consecutive patients with heart failure who received CRT devices with defibrillator and 20 age-matched, healthy control subjects. At baseline and 3 months and 6 months after CRT, we assessed New York Heart Association (NYHA) class, 6-minute walk distance, plasma sympathetic biomarker nerve growth factor, echocardiography, heart rate variability and cardiac presynaptic sympathetic function determined by iodine 123 metaiodobenzylguanidine scintigraphy. After CRT, NYHA class improved by 1 class ( P <0.001), and left ventricular ejection fraction increased by 8% ( P <0.001). Along with improvement in the standard deviation of all normal-to-normal R-R intervals (85.63±31.66 ms versus 114.79±38.99 ms; P =0.004) and the standard deviation of the averaged normal-to-normal R-R intervals (82.62±23.03 ms versus 100.50±34.87 ms; P =0.004), the delayed heart/mediastinum (H/M) ratio increased (1.82 [0.58] versus 1.97 [0.59]; P =0.03), whereas the mean (SD) H/M washout rate was reduced (48% [19%] versus 37% [22%]; P =0.01). Twenty-two of 45 study patients responded to CRT, with a reduction of left ventricular end-systolic volume index >15%. Compared with nonresponders, responders had a higher delayed H/M ratio (2.11 versus 1.48; P =0.003) and lower H/M washout rate (37% versus 62%; P =0.003) at baseline. Conclusions— CRT improved sympathetic function. Cardiac sympathetic reserve may be a marker for the reversibility of failing myocardial function.

Abstract Background: Inflammation is hypothesized to play a role in colorectal tumorigenesis. Circulating levels of C-reactive protein (CRP), a serologic marker of the inflammatory response, have been positively associated with colorectal cancer development in some studies; however, there are limited data on the relation of CRP with colorectal adenomas, established precursors of colorectal cancer. Methods: A nested case–control investigation of CRP levels and incident colorectal adenoma was conducted in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial, a randomized trial of 154,942 individuals designed to test the efficacy of flexible sigmoidoscopy on colorectal cancer mortality when performed once, and then repeated 3 to 5 years later. Serum CRP levels were measured in baseline blood specimens from participants who were free of polyps in the left-sided colorectum at the baseline screening procedure, but who were found at the subsequent screen to have at least one colorectal adenoma (n = 356), and in a set of polyp-free, frequency-matched controls (n = 396). Results: In a multivariable logistic regression model that included established colorectal adenoma risk factors, a 1-unit increase in log CRP level was associated with a 15% reduction in risk of developing colorectal adenoma (OR = 0.85, 95% CI, 0.75–0.98, Ptrend = 0.01). This association did not differ according to body size, smoking behavior, gender, use of nonsteroidal antiinflammatory drugs, or adenoma location. Conclusions: High circulating CRP levels may be protective against colorectal adenoma development. Impact: Though at contrast with mechanistic data on inflammation and colorectal tumorigenesis, this finding is not inconsistent with prior results on CRP and colorectal adenoma and warrants further investigation. Cancer Epidemiol Biomarkers Prev; 20(3); 537–44. ©2011 AACR.

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 4μM 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: Clin Cancer Res 2010;16(7 Suppl):A41

The spindle assembly checkpoint (SAC) is essential for proper sister chromatid segregation. Defects in this checkpoint can lead to chromosome missegregation and aneuploidy. An increasing body of evidence suggests that aneuploidy can play a causal role in tumorigenesis. However, mutant mice that are prone to aneuploidy have only mild tumor phenotypes, suggesting that there are limiting factors in the aneuploidy-induced tumorigenesis. Here we provide evidence that p53 is such a limiting factor. We show that aneuploidy activates p53 and that loss of p53 drastically accelerates tumor development in two independent aneuploidy models. The p53 activation depends on the ataxia-telangiectasia mutated (ATM) gene product and increased levels of reactive oxygen species. Thus, the ATM-p53 pathway safeguards not only DNA damage but also aneuploidy.