Pharmacological FAK inhibitors are specific in suppressing LIF and IL-6 in CMEC cells. To confirm the specificity of PF573228 (PF228) and PND-1186 (PND), FAK was first knocked down in CMECs with siRNA for 5 days followed by 4 h inhibitor treatments. Total FAK (tFAK) and pFAK protein knockdown was quantified by capillary western blots (A). For illustration purposes, synthetic bands were produced from chemiluminescence spectrograms (B). TUB, α-tubulin. (C) Quantification showing that siFAK decreases total FAK normalized to α-tubulin, which is not affected by the inhibitors PF228 or PND. (D–F) Similarly, siFAK decreased pY397-FAK levels, with the PF228 and PND decreasing pFAK only under control siRNA conditions (siCtrl). Critically, LIF (G) and IL-6 (H) gene expression (RT-qPCR) were not significantly different when the inhibitors were incubated with siCtrl or siFAK, and provided no additive suppression in the presence of siFAK, showing that their effects were entirely mediated through FAK. Data are means±s.e.m. of four independent experiments and presented relative to DMSO- and control (siCtrl)-treated cells. *P<0.05; **P<0.01; NS, not significant.