Triflorcas impairs survival and in vitro tumorigenesis of cancer cells resistant to single RTK inhibition through RTK swapping by also interfering with PDGFRβ phosphorylation.

<p>(A) Survival of U87 cells was reduced by Triflorcas in a dose dependent manner (µM; n = 2). SU11274 (SU), crizotinib (crizo), and PHA665752 (PHA) were used at the indicated concentrations (µM). (B and C) Triflorcas (TFC) impaired anchorage-independent growth of U87 cells, in a dose dependent manner (µM; n = 3). Gefitinib and SU11274 were used to inhibit ErbB1 and Met, respectively. (D) PDGFRβ phosphorylation in U87 cells was drastically reduced in presence of Triflorcas. For western blot analyses, cells were cultured in presence or absence of Triflorcas, SU11274 (SU), Imatinib (IMA), or Nilotinib (Nilo) (0.3–3 µM). Total cell lysates were analyzed using anti-phospho-Y₇₅₁-PDGFRβ (pY₇₅₁-PDGFRβ) (upper panel), anti-PDGFRβ (middle panel), or Tubulin (bottom panel). Values are expressed as means ± s.e.m. **P<0.01; ***P<0.001; Student-<i>t</i> test.