Fig. 5

Drug resistant breast cancer derived MPs induce CD44 dependent clustering of macrophage cells. Cluster formation in macrophage cells grown in a monolayer (a) prior to and (b–d) following Res-MP co-culture for 24 h, c in the presence of anti-CD44 or (d) in the presence anti-ICAM-1 antibody. Images were acquired under a 10× magnification. Representative images shown. e Graphical representation of macrophage clustering with Res-MP. Data represents mean ± SEM values of three independent experiments. The student’s unpaired two tailed T-test with Welch’s correction was used for statistical analysis. *P < 0.05, **P < 0.01 and ****P < 0.0001. f Res-MPs induce expression of ICAM-1 in macrophage cells. (i) 50% of breast cancer-derived Res-MPs are positive for ICAM-1. Macrophage cells following 4 h co-culture with Res-MP show an increase in ICAM-1 expression from (ii) 11% to (iii) 38% as determined by cell surface immunolabelling and flow cytometric detection. . Data is representative of a typical experiment. g Res-MPs selectively package hylauronic acid (HA). 30–50 μg lysates of the malignant drug sensitive breast adenocarcinoma cells (Sen), its drug resistant counterpart cells (Res) and the non-malignant D3 cells (D3) as well as MPs derived from them Sen-MP, Res-MP and D3-MP respectively were analysed by Western Blot analysis. The presence of HA was detected in the Res-MP only but not in the parental donor cell, the non-malignant cell neither their MPs. β-actin was used as an internal loading control. Representative data shown (n = 3)