Fig. 9. Electron microscopy of HMEC-1 cells grown in culture with DP siRNA show distinct differences in cell-cell adhesion when compared with control cells. (A) Untreated, wild-type (w.t.) cells plated for 5 hours on matrigel showed distinct microvilli extending from each cell (arrows). (B) Arrows point to microvilli between cells treated with DPsiRNA. Note, cells come in close contact with each other. Nu, nucleus. (C) High-magnification view of two juxtaposed cells 5 hours after plating onto matrigel shows two microvilli (from A) sliding across each other. Arrows show direction of progress for each microvilli. Arrowheads point to distinct amorphous material adhering microvilli to each other. (D) DPsiRNA does not appear to compromise microvilli sliding or their adhesion to one another. An amorphous material similar to that seen in untreated cells (C) adhering two microvilli to each other was clearly visible (arrowheads). (E) Later stages of cell adhesion are evident 24 hours after plating onto matrigel. Areas of adhesion between untreated cells commonly spanned >3 µm (arrows), while areas of adhesion between DPsiRNA-treated cells rarely spanned beyond 500 nm (F). While some intercellular spaces were evident between untreated cells (asterisk in E), morphologically similar spaces were commonplace between DPsiRNA-treated cells (asterisks in F). (G-H) High-magnification views of complexus adherens junctions in untreated cells 24 hours after plating onto matrigel. Arrows point to filaments with diameters of 10-12 nm (similar to vimentin) coming into close contact with electron dense plaques (arrowheads in G and H). Bar in G = 100 nm in H.