Fig. 6.

OPN receptors on the MSC cell membrane affect OPN-mediated TA-MSC formation. (A) Pretreatment of MSCs with αvβ1, αvβ3, αvβ5, or CD44 siRNAs for 24 h was followed by A549-L CM incubation for another 24 h. The resulting TA-MSC CM was collected and used to quantify cancer cell migration and invasion. (B and C) The Transwell assay examined levels of lung cancer cell migration. (D and E) The invasion assay examined levels of lung cancer cell invasion. (F) The model shows that lung cancer cells secrete OPN, which promotes the transformation of MSC cells into TA-MSCs via integrins and CD44, stimulating the invasiveness of lung cancer cells. All results are expressed as the mean ± SD of three independent samples. *p < 0.05 compared with controls; #p < 0.05 compared with 1 μM B[α]P or 1% CSE treatment.