Enteropathogenic Escherichia coli dynamically regulates EGFR signaling in intestinal epithelial cells.

The diarrheagenic pathogen enteropathogenic Escherichia coli (EPEC) dynamically modulates the survival of infected host intestinal epithelial cells. In the initial stages of infection, several prosurvival signaling events are activated in host cells. These include the phosphorylation of epidermal growth factor receptor (EGFR) and the consequent activation of the phosphatidylinositol-3 kinase/Akt pathway. While studying this pathway in infected epithelial cells, we observed EGFR depletion at later stages of infection, followed subsequently by a decrease in phospho-EGFR. EGFR loss was not dependent on receptor phosphorylation, or on canonical proteasome- and lysosome-dependent processes. Although a type III secretion mutant (ΔescN) stimulated EGFR phosphorylation, it failed to induce receptor degradation. To identify the specific EPEC effector molecule(s) that influenced EGFR stability, epithelial cells infected with isogenic mutant EPEC strains were examined. An EPEC ΔespF strain failed to induce EGFR degradation, whereas EPEC ΔespZ accentuated receptor loss in infected cells. Given the known and contrasting effects of EspF and EspZ on caspase activation, and the known role of proteases in cleaving EGFR, we explored the effect of caspase inhibitors on infection-dependent EGFR loss. The pan-caspase inhibitor Q-VD-OPh blocked EPEC-induced EGFR cleavage in a dose-dependent manner. Taken together, our data suggest that EPEC EspF stimulates caspase-dependent EGFR cleavage and loss, whereas EspZ inhibits this process. Whereas EGFR phosphorylation contributes to the survival of host cells early in infection, EspF-driven caspase activation and consequent EGFR loss likely induce a precipitous increase in host cell death later in the infectious process.

The benefits and challenges of using computer-assisted symptom assessments in oncology clinics: results of a qualitative assessment.

Developed for clinical use in oncology settings, the Patient Assessment, Care & Education (PACE) System is a computer technology tool designed to address the under-identification and treatment of chemotherapy-related symptoms. This system includes general core questions together with the Patient Care Monitor (PCM), a validated questionnaire that assesses patient-reported problems, six symptom burden indices, and one global quality of life index. The system automatically scores the PCM and generates a written report. The objective of this study was to assess the manner in which clinicians use this system and identify the benefits and challenges that oncology clinics may face when adopting this system. The study was part of a larger evaluation of the system that included standardized surveys and chart review. Sixteen providers (physicians, nurses, and physician assistants) at 13 community oncology clinics participated in a 30-minute interview. Responses were coded according to common phrases or concepts. Clinicians indicated that they use the system mainly for symptom assessment or review of systems. The most common benefits identified included the improved ability to identify under-reported symptoms, enhanced communication with patients; increased efficiency; and its ability to highlight patients' most bothersome symptoms. Challenges included patient burden from the frequent need to answer the questionnaires, issues with the wording and formatting of the screening questionnaire, and technical difficulties. In sum, these interviews suggest that electronic symptom assessments offer potential advantages in terms improving the integration of routine assessment of patients' symptoms and health-related quality of life into the daily flow of an oncology clinic. The approach should receive additional research and development attention.