Aberrant regulation of cellular extrusion can promote invasion and metastasis. Here, we identify molecular requirements for early cellular invasion using a premalignant mouse model of pancreatic cancer with conditional knockout of p120 catenin (Ctnnd1). Mice with biallelic loss of p120 catenin progressively develop high grade PanIN lesions and neoplasia accompanied by prominent acute and chronic inflammatory processes, which is mediated in part through nuclear factor-kB (NF-kB) signaling. Loss of p120 catenin in the context of oncogenic Kras also promotes remarkable apical and basal epithelial cell extrusion. Abundant single epithelial cells exit PanIN epithelium basally, retain epithelial morphology, survive, and display features of malignancy. Similar extrusion defects are observed following p120 catenin knockdown in vitro, and these effects are completely abrogated by activation of S1P/S1pr2 signaling. In the context of oncogenic Kras, p120 catenin loss significantly reduces expression of genes mediating S1P/S1pr2 signaling in vivo and in vitro, and this effect is mediated at least in part through activation of NF-kB. These results provide insight into mechanisms controlling early events in the metastatic process and suggest that p120 catenin and S1P/S1pr2 signaling enhance cancer progression by regulating epithelial cell invasion.

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Introduction: Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA) is used for aortic control in hemorrhagic shock despite little quantification of its mechanism of resuscitation or cardiac injury. The goal of this study was to use pressure-volume (PV) loop analysis and direct coronary blood flow measurements to describe the physiologic changes associated with the clinical use of REBOA.Methods: Swine underwent surgical and vascular access to measure left ventricular PV loops and left coronary flow in hemorrhagic shock and subsequent placement of occlusive REBOA, partial REBOA, and no REBOA. PV loop characteristics and coronary flow are compared graphically with PV loops and coronary waveforms, and quantitatively with measures of the end systolic and end pressure volume relationship, and coronary flow parameters, with accounting for multiple comparisons.Results: Hemorrhagic shock was induced in five male swine (mean 53.6 ± 3.6 kg) as demonstrated by reduction of stroke work (baseline: 3.1 vs. shock: 1.2 L*mmHg, p < 0.01) and end systolic pressure (ESP; 109.8 vs. 59.6 mmHg, p < 0.01). ESP increased with full REBOA (178.4 mmHg; p < 0.01), but only moderately with partial REBOA (103.0 mmHg, p < 0.01 compared to shock). End systolic elastance was augmented from baseline to shock (1.01 vs. 0.39 ml/mmHg, p < 0.01) as well as shock compared to REBOA (4.50 ml/mmHg, p < 0.01) and partial REBOA (3.22 ml/mmHg, p = 0.01). Percent time in antegrade coronary flow decreased in shock (94%–71.8%, p < 0.01) but was rescued with REBOA. Peak flow increased with REBOA (271 vs. shock: 93 ml/min, p < 0.01) as did total flow (peak: 2136, baseline: 424 ml/min, p < 0.01). REBOA did not augment the end diastolic pressure volume relationship.Conclusion: REBOA increases afterload to facilitate resuscitation, but the penalty is supraphysiologic coronary flows and imposed increase in LV contractility to maintain cardiac output. Partial REBOA balances the increased afterload with improved aortic system compliance to prevent injury.

Retrograde Endovascular Balloon Occlusion of the Aorta (REBOA) is frequently used in hemorrhagic shock to facilitate resuscitation. In theory, aortic occlusion increases afterload and focuses perfusion to the coronary arteries and great vessels; also to focus perfusion to the brain. It is, however, unknown exactly how and to what extent REBOA impacts cardiovascular parameters such as preload, afterload and contractility, or coronary artery blood flow. It is also not known how these parameters evolve over time during REBOA as it is shifted from fully to partially occlusive, or weaned down entirely. We aim to use left ventricular Pressure-Volume (PV) loop analysis and directly measure coronary flow in swine as they descend into hemorrhagic shock, are resuscitated with full aortic occlusion with REBOA, transitioned to partial aortic occlusion with REBOA, and then weaned completely off of the REBOA and are resuscitated. We will examine, specifically, measures of preload, afterload, contractility and coronary blood flow during each study time period (baseline, hemorrhagic shock, full aortic occlusion, partial aortic occlusion, and post-occlusion during resuscitation).