MDM2 and SFRP1 in centrosome amplification. (A) Basal levels of MDM2, semaphorin 6A and SFRP1 are higher in unsynchronized populations of MCF10A cells compared to Her2+ breast cancer cell lines. (B) MCF10A cells were transfected with siRNA duplexes against MDM2 or SFRP1. Western blots indicate the transient knockdown of MDM2 and SFRP1. Quantifications of centrosome amplification by pericentrin immunofluorescence (C) and of BrdU incorporation by fluorescence microscopy (D).