Fig. 5.

β1 integrin mediates the protective effect of LM05-F-conditioned media, but EGFR is not involved in FN’s protective effect. a To establish whether β1 integrin played a role in LM05-F-conditioned media (FCM) induced tamoxifen resistance, LM05-E cells were plated in the presence of non-conditioned media (NCM) or FCM and treated with 10 nM estradiol (E₂) or estradiol plus 1 µM 4-OH-tamoxifen (E₂ + T). The addition of AIIB2 reversed the protective effect of FCM on E₂ + T treated cells, but did not significantly affect the E₂ treated cells; (**P<0.01; ***P<0.001). b To test the involvement of EGFR on FN’s protective effect, LM05-E cells were cultured on BSA (control) or FN and treated for 48 h with 10 nM estradiol (E₂) or 10 nM E₂ + 1 µM 4-OH-tamoxifen (E₂ + T) in the presence of the EGFR inhibitor AG1478 (AG; 6.4 µM). AG1478 did not reverse the protective effect of FN (***P<0.001). One of at least two experiments is shown