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Summary Background Screening for Barrett's oesophagus relies on endoscopy, which is invasive and few who undergo the procedure are found to have the condition. We aimed to use machine learning techniques to develop and externally validate a simple risk prediction panel to screen individuals for Barrett's oesophagus. Methods In this prospective study, machine learning risk prediction in Barrett's oesophagus (MARK-BE), we used data from two case-control studies, BEST2 and BOOST, to compile training and validation datasets. From the BEST2 study, we analysed questionnaires from 1299 patients, of whom 880 (67·7%) had Barrett's oesophagus, including 40 with invasive oesophageal adenocarcinoma, and 419 (32·3%) were controls. We randomly split (6:4) the cohort using a computer algorithm into a training dataset of 776 patients and a testing dataset of 523 patients. We compiled an external validation cohort from the BOOST study, which included 398 patients, comprising 198 patients with Barrett's oesophagus (23 with oesophageal adenocarcinoma) and 200 controls. We identified independently important diagnostic features of Barrett's oesophagus using the machine learning techniques information gain and correlation-based feature selection. We assessed multiple classification tools to create a multivariable risk prediction model. Internal validation of the model using the BEST2 testing dataset was followed by external validation using the BOOST external validation dataset. From these data we created a prediction panel to identify at-risk individuals. Findings The BEST2 study included 40 diagnostic features. Of these, 19 added information gain but after correlation-based feature selection only eight showed independent diagnostic value including age, sex, cigarette smoking, waist circumference, frequency of stomach pain, duration of heartburn and acidic taste, and taking antireflux medication, of which all were associated with increased risk of Barrett's oesophagus, except frequency of stomach pain, with was inversely associated in a case-control population. Logistic regression offered the highest prediction quality with an area under the receiver-operator curve (AUC) of 0·87 (95% CI 0·84–0·90; sensitivity set at 90%; specificity of 68%). In the testing dataset, AUC was 0·86 (0·83–0·89; sensitivity set at 90%; specificity of 65%). In the external validation dataset, the AUC was 0·81 (0·74–0·84; sensitivity set at 90%; specificity of 58%). Interpretation Our diagnostic model offers valid predictions of diagnosis of Barrett's oesophagus in patients with symptomatic gastro-oesophageal reflux disease, assisting in identifying who should go forward to invasive confirmatory testing. Our predictive panel suggests that overweight men who have been taking antireflux medication for a long time might merit particular consideration for further testing. Our risk prediction panel is quick and simple to administer but will need further calibration and validation in a prospective study in primary care. Funding Charles Wolfson Charitable Trust and Guts UK.

Heterogeneity among aldosterone-producing adenomas (APAs) has been highlighted by the discovery of somatic mutations. KCNJ5 mutations predominate in large zona fasciculata (ZF)–like APAs; mutations in CACNA1D , ATP1A1, ATP2B3 , and CTNNB1 are more likely to be found in small zona glomerulosa (ZG)–like APAs. Microarray comparison of KCNJ5 mutant versus wild-type APAs revealed significant differences in transcriptomes. NEFM , encoding a neurofilament subunit which is a D1R (dopamine D1 receptor)–interacting protein, was 4-fold upregulated in ZG-like versus ZF-like APAs and 14-fold more highly expressed in normal ZG versus ZF. Immunohistochemistry confirmed selective expression of NEFM (neurofilament medium) polypeptide in ZG and in ZG-like APAs. Silencing NEFM in adrenocortical H295R cells increased basal aldosterone secretion and cell proliferation; silencing also amplified aldosterone stimulation by the D1R agonist, fenoldopam, and inhibition by the D1R antagonist, SCH23390. NEFM coimmunoprecipitated with D1R, and its expression was stimulated by fenoldopam. Immunohistochemistry for D1R was mainly intracellular in ZG-like APAs but membranous in ZF-like APAs. Aldosterone secretion in response to fenoldopam in primary cells from ZF-like APAs was higher than in cells from ZG-like APAs. Transfection of mutant KCNJ5 caused a large reduction in NEFM expression in H295R cells. We conclude that NEFM is a negative regulator of aldosterone production and cell proliferation, in part by facilitating D1R internalization from the plasma membrane. Downregulation of NEFM in ZF-like APAs may contribute to a D1R/D2R imbalance underlying variable pharmacological responses to dopaminergic drugs among patients with APAs. Finally, taken together, our data point to the possibility that ZF-like APAs are in fact ZG in origin.

Aldosterone-producing adenomas (APAs) vary in phenotype and genotype. Zona glomerulosa (ZG)-like APAs frequently have mutations of an L-type calcium channel (LTCC) CaV1.3. Using a novel antagonist of CaV1.3, compound 8, we investigated the role of CaV1.3 on steroidogenesis in the human adrenocortical cell line, H295R and in primary human adrenal cells. This investigational drug was compared with the common antihypertensive drug nifedipine, which has 4.5-fold selectivity for the vascular LTCC, CaV1.2, over CaV1.3. In H295R cells transfected with wild-type or mutant CaV1.3 channels, the latter produced more aldosterone than wild-type, which was ameliorated by 100 μM of compound 8. In primary adrenal and non-transfected H295R cells, compound 8 decreased aldosterone production similar to high concentration of nifedipine (100 μM). Selective CaV1.3 blockade may offer a novel way of treating primary hyperaldosteronism, which avoids the vascular side effects of CaV1.2-blockade and provides targeted treatment for ZG-like APAs with mutations of CaV1.3.

5081Background: The effect of novel drugs can be studied in primary prostate cancer (PC), if given prior to radical prostatectomy (RP). Altered PI3K/AKT/mTOR signalling is associated with aggressiv...

97 Background: Additional systemic therapy given to unselected patients (pts) around RP has yet to improved pt survival. Further trials should use appropriate pt selection, i.e. men at highest risk of relapse, ideally biomarker stratified. Using novel drugs prior to RP allows direct study of effects in primary prostate cancer (PC) that may guide design of future trials. Altered PI3K/AKT/mTOR pathway signalling is associated with aggressive PC hence we have undertaken a study vistusertib, an oral, dual mTORC1/mTORC2 inhibitor prior to RP. Methods: Primary endpoint was to measure mTOR1/2 inhibition by immunohistochemistry (IHC). Secondary endpoints were feasibility, safety, tolerability and determining plasma concentrations of vistusertib. Exploratory objectives included measurement of anti-cancer effects. Men, due for RP, with high volume or aggressive PC consented and received vistusertib, 50mg bd, for 15 days prior to RP. Diagnostic biopsy and RP tissue were collected for IHC. Adverse events (AE) were graded according to CTCAE v4. Plasma was collected to determine vistusertib concentrations. Results: 21 men, median age 62 (range 50 – 69) included 11 intermediate and 10 high risk PC. 18/21 were evaluable for primary endpoint. On day of RP mean plasma vistusertib concentration at RP was 648 ng/mL (range 386-852) and 6-8 hr post dose 484 ng/mL (range 211-660). Majority of related AEs were Grade (Gr) 1, the most common being rash, thrombocytopenia, oral mucositis, diarrhoea, lymphopenia and fatigue. Six pts experienced Gr3 AEs (3 pt lymphopenia, 1 pt each rash, mucositis and ALT rise). Two pts discontinued due to AEs (mucositis, thrombocytopenia) and one withdrew consent. Surgery was delayed in one pt (Gr 1 thrombocytopenia). IHC confirmed at RP: 4EBP1 was reduced in 100% pt (75% no staining post vistusertib) and pS6 was reduced in 67%, not changed in 25% and increased in 8%. A fall in PSA occurred in 4/18 pts. Conclusions: 2 weeks of AZD2014 can be given prior to RP. Active plasma concentrations were achieved. mTOR pathway inhibition was confirmed on IHC and a PSA fall occurred in 22% of pt. Analysis is ongoing, to be informed by concomitant studies in a PTEN null PC model. Clinical trial information: NCT02064608.

Clinical studies have shown the improved benefit of combining androgen deprivation therapy (ADT) with radiotherapy, indicating a potential interaction between the androgen signalling and DNA damage response (DDR) pathways in PCa. We have explored the underlying basis of this interaction by interrogating the mechanism of androgen regulation of the DDR in men with PCa, both untreated and treated with an androgen inhibitor. We show that androgen receptor (AR) signalling regulates the DDR and promotes DDR foci formation leading to ATM activation in PCa. Our data showing that AR regulates DDR provides an explanation for the improved outcome of combined ADT and radiotherapy. Thus, our work identifies the rationale for targeting both the AR and DDR pathways simultaneously to improve therapy outcome in advanced or high risk prostate cancer. Citation Format: Mohammad Asim, Heather Zecchini, Firas Tarish, Charlie Massie, Ajoeb Baridi, Anne Warren, Wanfeng Zhao, Leigh-Anne McDuffus, Patrice Mascalchi, Greg Shaw, Harveer Dev, Karan Wadhwa, Paul Wijnhoven, Josep Forment, Scott Lyons, Andy Lynch, Cormac O’Neill, Vincent Zecchini, Paul Rennie, Aria Baniahmad, Simon Tavare, Ian Mills, Niklas Schulz, Yaron Galanty, Thomas Helleday, David Neal. The human androgen receptor regulates DNA damage response (DDR) in prostate cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr LB-176.

Resistance to androgen deprivation therapy (ADT) and the development of castration resistant prostate cancer (CRPC) remains a major challenge in the treatment of advanced prostate cancer (PCa). Elucidation of resistance mechanisms leading to CRPC is essential to develop novel therapeutic interventions. Using a systems biology approach, we interrogated the androgen-regulated proteome and identified a mitotic Kinase as a novel androgen regulated kinase in PCa. The kinase was shown to be androgen-regulated in PCa and its nuclear localisation significantly increased in CRPC and was associated with biochemical relapse. Interestingly, the Kinase interacted directly with the amino terminus transactivation and carboxy terminus ligand binding domain of androgen receptor (AR), resulting in stabilisation of AR protein and its activity. The AR-driven global transcriptional program was regulated by this coactivator kinase including pathways involved in tumour invasion and metastasis. The inhibition of the kinase function decreased AR levels and activity, and slowed growth of PCa cell lines and human PCa explants. Thus the mitotic kinase is a novel AR-Stablised kinase with potential for clinical applications as both a candidate biomarker of PCa progression and a therapeutic target in advanced disease. Citation Format: Mohammad Asim, Charlie Massie, Anne Warren, Katarina Luko, Brinder Chohan, Suraj Menon, Ajoeb Baridi, Folake Orafidiya, Wanfeng Zhao, Carlos Escriu, Hisham Mohammed, Clive D’Santos, Xiaoping Yang, Chris Taylor, Arham Qureshi, Kate Watt, Vincent Zecchini, Luke Selth, Scott Dehm, Ian Mills, Jason Carroll, Wayne Tilley, Iain McEwan, Aria Baniahmad, David Neal. Androgen-regulated proteome reveals a therapeutically relevant androgen receptor coactivator target in prostate cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr LB-003.