Citations

BK channels are major ionic determinants of vasodilation. BK channel function is impaired in diabetic vessels due to accelerated proteolysis of its beta-1 (BK-β1) subunits in response to increased oxidative stress. The nuclear factor E2-related factor-2 (Nrf2) signalling pathway has emerged as a master regulator of cellular redox status, and we hypothesized that it plays a central role in regulating BK channel function in diabetic vessels. We found that Nrf2 expression was markedly reduced in db/db diabetic mouse aortas, and this was associated with significant downregulation of BK-β1. In addition, the muscle ring finger protein 1 (MuRF1), a known E-3 ligase targeting BK-β1 ubiquitination and proteasomal degradation, was significantly augmented. These findings were reproduced by knockdown of Nrf2 by siRNA in cultured human coronary artery smooth muscle cells. In contrast, adenoviral transfer of Nrf2 gene in these cells downregulated MuRF1 and upregulated BK-β1 expression. Activation of Nrf2 by dimethyl fumarate preserved BK-β1 expression and protected BK channel and vascular function in db/db coronary arteries. These results indicate that expression of BK-β1 is closely regulated by Nrf2 and vascular BK channel function can be restored by Nrf2 activation. Nrf2 should be considered a novel therapeutic target in the treatment of diabetic vasculopathy.

Coronary artery aneurysm is defined as a coronary dilation that exceeds the diameter of adjacent segments or the diameter of the patient's largest normal coronary vessel by 1.5×. It is an uncommon disease that has been diagnosed with increasing frequency since the widespread appearance of coronary angiography. The published incidence varies from 1.5% to 5%, suggesting male dominance and a predilection for the right coronary artery. Although several causes have been described, atherosclerosis accounts for ≥50% of coronary aneurysms in adults. Reported complications include thrombosis and distal embolization, rupture, and vasospasm, causing ischemia, heart failure, or arrhythmias. The natural history and prognosis remain unknown, as definitive data are scarce. Controversies persist regarding the use of medical management (antithrombotic therapy) or interventional/surgical procedures. Only some case reports or small case series are available about this condition. The Coronary Artery Aneurysm Registry (CAAR; http://www.ClinicalTrials.gov NCT02563626) is a multicenter international ambispective registry that aims to provide insights on anatomic, epidemiologic, and clinical aspects of this substantially unknown entity. In addition, the registry will assess management strategies (conservative, interventional, or surgical) and their short‐ and long‐term results in a large cohort of patients.Clinical Trial registration: ClinicalTrials.gov. Unique identifier: NCT02563626.

675 Background: Recent retrospective analysis of CALGB/SWOG 80405 showed that left-sided colon cancers (LCC) respond differently to biological therapy compared with right-sided tumors. However, differences between rectal cancers (RC) and LCC remain undefined. Herein, we report our exploration of differences between these two groups. Methods: Individual patient data from 4182 patients (pts) with metastatic colorectal cancers, enrolled onto 8 first-line randomized trials, were pooled. Only pts with tumor locations that were clearly defined as LCC (splenic flexure to sigmoid) or RC were included in this analysis. Differences in pt characteristics and disease factors according to LCC vs. RC were identified. The prognostic effect of primary tumor location on OS and PFS was quantified via multivariable Cox proportional hazards modeling stratified by treatment arm within each study and adjusting for age, sex, performance status, and prior surgery. Results: In total, 2,479 (59%) pts with LCC and 1,703 (41%) pts with RC were identified. Pts with RC, compared with LCC, were more likely to be male (68% vs. 62%, p < 0.001), have lung metastases (mets) (56% vs. 37%, p < 0.001), and have 2 or more metastatic sites (64% vs. 60%, p < 0.02), whereas pts with LCC were more likely to have liver mets (84% vs. 76%, p < 0.001). RC had a greater frequency of KRAS mutations (41% vs. 37%, p = 0.04) than LCC but there were no differences in the frequency of BRAF mutations (5% vs. 4%, p = 0.2). In multivariable analysis, no differences in OS or PFS were observed between pts with LCC vs. RC. While risk of death did not differ by primary tumor location, across all pts with LCC or RC, those with liver mets had a 17% increased risk of death compared to those with lung mets (HR = 1.17, p = 0.03) after adjusting for effects of other variables. Forthcoming prognostic analysis of LCC vs. RC within grouped backbone treatments (e.g., FOLFOX and FOLFIRI) is underway. Conclusions: Tumors arising in the rectum may carry clinical and molecular features that are distinct from LCC. Further investigations are warranted to determine whether RC should be treated with the same chemo backbone and biological therapy as LCC.

256 Background: B7-H3 (CD276), part of the B7 superfamily, has been shown to play an immunomodulatory role, however its regulation, receptor and mechanism of action remain unclear. Protein levels of B7-H3 have been previously shown to relate to prostate cancer outcomes and currently, humanized monoclonal antibodies are being developed for clinical use (MGA271, Macrogenics). Here we use genomic expression data to examine the relationship of B7-H3 to prostate cancer outcomes and molecular subtypes. Methods: Prostatectomy tissue from 905 patients were profiled using the Affymetrix HuEx 1.0 ST microarray. Kruskal-Wallis tests were used to identify significant associations of B7-H3 expression with clinico-pathologic variables, and survival analysis were used to evaluate the prognostic value of B7-H3. Pearson’s correlation analyses were also performed to assess the relationship of B7-H3 expression with molecular subtypes and individual transcripts. Androgen receptor (AR) occupancy of promoter regions was derived in silico from chromosomal immune-precipitation (ChIP) data. Results: B7-H3 expression was positively associated with Gleason score (p < 0.01) and tumor stage (p < 0.01). High B7-H3 expression also correlated with the development of metastasis and prostate cancer specific mortality (HR of 3.4 and 2.4 respectively, p < 0.05 for both), but this was not significant on multi-variable analysis. B7-H3 was positively associated with ERG+ disease (n = 670, r = 0.85, p < 0.05) and AR expression (n = 670, r = 0.46, p < 0.001). B7-H3 was found to be one of the most correlated genes with AR (95th percentile) and ChIP analysis revealed AR binding upstream of B7-H3, suggesting potential androgen dependent regulation. Conclusions: B7-H3 expression correlates with high Gleason grade and advanced prostate cancer stage with higher quartiles of expression portending poor oncologic outcomes in two independent prostatectomy cohorts. B7-H3 expression appears to relate to the androgen receptor.

We described physical activity measures and hourly patterns in patients with chronic obstructive pulmonary disease (COPD) after stratification for generic and COPD-specific characteristics and, based on multiple physical activity measures, we identified clusters of patients. In total, 1001 patients with COPD (65% men; age, 67 years; forced expiratory volume in the first second [FEV 1 ], 49% predicted) were studied cross-sectionally. Demographics, anthropometrics, lung function and clinical data were assessed. Daily physical activity measures and hourly patterns were analysed based on data from a multisensor armband. Principal component analysis (PCA) and cluster analysis were applied to physical activity measures to identify clusters. Age, body mass index (BMI), dyspnoea grade and ADO index (including age, dyspnoea and airflow obstruction) were associated with physical activity measures and hourly patterns. Five clusters were identified based on three PCA components, which accounted for 60% of variance of the data. Importantly, couch potatoes (i.e. the most inactive cluster) were characterised by higher BMI, lower FEV 1 , worse dyspnoea and higher ADO index compared to other clusters ( p < 0.05 for all). Daily physical activity measures and hourly patterns are heterogeneous in COPD. Clusters of patients were identified solely based on physical activity data. These findings may be useful to develop interventions aiming to promote physical activity in COPD.

314 Background: Small bowel adenocarcinoma (SB-ACA) is rare, having little prospective data guiding management. A prior phase I study evaluated UGT1A1 genotype specific dosing of oxaliplatin, irinotecan, and capecitabine. Our prospective, multicenter clinical trial assessing tumor response in pts having metastatic SB-ACA, used a similar dosing strategy. Methods: Genotypes were determined via central lab. Previously untreated pts were dosed by UGT1A1*28 genotypes 6/6, 6/7, and 7/7 receiving 100/85/85 mg/m2 oxaliplatin d1, 150/150/75 mg/m2 irinotecan d1, and 1600/400/200 mg/m2 capecitabine (BID) d2-15 of 21 days. The study design was such that 1 confirmed response in 16 pts expanded enrollment to 33 pts, with 7 required for demonstrating efficacy. Results: 28 pts (13-6/6, 10-6/7, 5-7/7) have been enrolled [75% male, mean age 62.5 (range 41-77)]. Location of primary included: duodenum (63%), jejunum (26%), and ileum (7%), with pts having >1 metastatic site (abdominal-41%, bone-7%, liver-56%, lung-30%, nodal-52%, subcutaneous-4%, other-19%). Gr 3+ treatment related toxicity was not significantly different by genotype (50%-6/6, 44%-6/7, 20%-7/7, p=0.48) and included (pts): diarrhea(5), vomiting(5), leukopenia(5), neutropenia(7), and nausea(6). 57% (13 of 23) pts achieved responses during therapy, with a confirmed response rate of 39% (95% CI 0-58%). 18 have died, with a median follow-up of 8.3 mos (range 0-43). Conclusions: UGT1A1 genotype directed dosing with oxaliplatin, irinotecan, and capecitabine appears to result in prolonged response in this population. Larger studies are needed to determine comparability to CapeOx alone or if response/toxicity differs among genotypes. Supported by NIH Grant CA25224, Sanofi-Aventis, and Pfizer. [Table: see text]