Unintentional unblinding in rheumatic disease trials.

The practice of blinding treatment assignment in randomised controlled trials mitigates important biases in observational studies. Unblinding, whereby study participants or investigators become aware of treatment assignments, is an important threat to the validity of trial results. Rheumatology studies might be particularly susceptible to unblinding because rheumatic disease therapies often cause high rates of idiosyncratic side-effects and frequently rely on subjective endpoints. Despite this susceptibility, the degree to which unblinding occurs in randomised controlled trials in rheumatic diseases has rarely been assessed during trials or acknowledged as a limitation. Rheumatologists should be aware of this important threat to the validity of trial results, assessments of unblinding should be undertaken, and strategies to prevent unblinding should be deployed when feasible.

The expression of Nectin-4 on the surface of ovarian cancer cells alters their ability to adhere, migrate, aggregate, and proliferate.

The cell adhesion molecule Nectin-4 is overexpressed in epithelial cancers, including ovarian cancer. The objective of this study was to determine the biological significance of Nectin-4 in the adhesion, aggregation, migration, and proliferation of ovarian cancer cells. Nectin-4 and its binding partner Nectin-1 were detected in patients' primary tumors, omental metastases, and ascites cells. The human cell lines NIH:OVCAR5 and CAOV3 were genetically modified to alter Nectin-4 expression. Cells that overexpressed Nectin-4 adhered to Nectin-1 in a concentration and time-dependent manner, and adhesion was inhibited by antibodies to Nectin-4 and Nectin-1, as well as synthetic Nectin peptides. In functional assays, CAOV3 cells with Nectin-4 knock-down were unable to form spheroids and migrated more slowly than CAOV3 parental cells expressing Nectin-4. NIH:OVCAR5 parental cells proliferated more rapidly, migrated faster, and formed larger spheroids than either the Nectin-4 knock-down or over-expressing cells. Parental cell lines expressed higher levels of epithelial markers and lower levels of mesenchymal markers compared to Nectin-4 knock-down cells, suggesting a role for Nectin-4 in epithelial-mesenchymal transition. Our results demonstrate that Nectin-4 promotes cell-cell adhesion, migration, and proliferation. Understanding the biology of Nectin-4 in ovarian cancer progression is critical to facilitate its development as a novel therapeutic target.