Imatinib inhibits in vitro proliferation of cells derived from a pleural solitary fibrous tumor expressing platelet-derived growth factor receptor-beta.

We examined the in vitro effects of imatinib (Novartis Pharma AG, Basel, Switzerland) as a possible inhibitor of PDGFR pathway on cells derived from a recurrence of a pleural malignant solitary fibrous tumor (SFT). Primary cell culture was characterised by immunofluorescence. SFT-derived cells were treated with imatinib at different time points. Western blotting for PDGFR-beta, phospho-PDGFR-beta or smooth muscle actin (SMA) was performed before and after 96 h of treatment with imatinib. SFT-derived cells treated with imatinib for 96 h showed a dose dependent decrease of Ki67 expression. Results were confirmed by growth curve. Western blotting showed that PDGFR-beta was highly expressed and phosphorylated in SFT-derived cells and imatinib treatment reduced PDGFR-beta phosphorylation and SMA expression. With the limit of experimental findings, our results support a possible future application of imatinib as a candidate molecule in the target therapy of malignant SFTs over-expressing wild-type PDGFR.