Fig. 5

α3 reduction causes increased invasiveness of HER2+, but not triple-negative human carcinoma cells. a Flow cytometry histograms of signal intensity of α3 show successful α3 deletion in AU565, SKBR3, BT474, and MDA-MB-231cells. b–d Invasion assays through gel-coated (Matrigel-collagen I or Matrigel only) membrane. Bottom—representative images of the part of the membrane, showing DAPI-stained nuclei of invading cells. Top—analysis of the experiments, performed in duplicate and repeated three times. (mean ± SD, unpaired t test, *P < 0.05, **P < 0.005) b The reduction of α3 increases the invasiveness of HER2+ carcinoma cells through the mixture of collagen I and Matrigel under interstitial fluid flow conditions. c Under static conditions, HER2+ cells show strongly reduced and α3-independent invasion. Contrary, the invasion of triple-negative MDA-MB-231 is α3-dependent. d The absence of collagen I causes an increased invasion of α3WT HER2+ carcinoma cells, resulting in similar levels of invasion between α3KO and WT cells