Recombinant adeno-associated virus (AAV) is a promising non-pathogenic vector in the emerging field of gene therapy. For AAV serotype 2 (AAV-2) infection, experimental evidence points to an involvement of heparan sulphate proteoglycans (HSPG), but also to the existence of additional receptors. We investigated a potential role of the tetraspanin CD9 in AAV-2 infection of breast cancer cells mainly because it binds to the heparin-binding EGF-like growth factor, suggesting that it may also interact with a heparin-binding virus. Among breast cancer cell lines, expression of HSPG or potential AAV-2 (co)-receptors was not found to correlate with transduction efficiency. In complete accordance with the role of CD9, blocking with anti-CD9 antibodies resulted in drastically decreased AAV-2 transduction efficiencies in cell lines with low expression of HSPG. Furthermore, specific inhibition of CD9 expression with siRNA resulted in fewer transgene-positive cells, whereas overexpression of CD9 in the breast cancer cell line T47D as well as in BT8Ca and BT12Ca rat glioma cells (with low background expression of HSPG and CD9) increased the number of AAV-transduced cells. The minimal epitope recognized by antibody 72F6, which most efficiently blocked AAV-mediated transgene expression, was deduced from the specific binding to peptides immobilized on colour-encoded microspheres consisting of the amino acid sequence PKKDV located in the large extracellular loop of CD9. Our results clearly point to an involvement of CD9 in the attachment, uptake or processing of AAV-2 by target cells expressing low amounts of HSPG, which may help to define cell populations accessible in AAVbased therapeutic applications.

The efficiency of rAAV-mediated gene transfer into breast cancer cells is significantly higher than previously reported and can be further enhanced by co-administration of chemotherapeutic agents. We also confirmed that breast cancer cells can activate human dendritic cells after infection with a CD40L-encoding rAAV.

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The various efficient methods available for bowel preparation prior to colonoscopy differ in patient acceptance. Combining the laxative sodium picosulfate with hyperosmotic magnesium citrate, used in this study in the formulation CitraFleet(®), allows the uptake of the purgative substances as a solution of low volume. This observational study with 737 patients evaluated efficacy of bowel preparation, potential side or adverse effects and patient acceptance of this medicinal product when used by resident physicians in Germany.Colon cleansing with CitraFleet(®) was considered very good to sufficient in 95.2 % of the patients and inadequate in only 4.8 %. In 75 % of the colonoscopies, bowel preparation was rated very good or good. Compared to the standard regimen of two portions taken the day before endoscopy, cleaning efficacy was better when patients received one of the doses on the morning of the day of colonoscopy. The quality of bowel preparation was rated lower by gastroenterologists without any prior experience with sodium picosulfate/magnesium citrate. The overall assessment of the colon cleansing procedure by the 76 participating physicians was very positive and patient acceptance was also very high which can be considered a clear advantage over alternative methods. Efficacy of colon cleansing with CitraFleet(®) was not substantially affected by typical deviations from the recommended standard procedure, emphasizing the robustness of the method. Only one of the patients reported a mild adverse effect potentially caused by the cleansing agents.

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