Centrosomes, the primary microtubule organizing centers within cells, are commonly amplified in tumors, but the role of centrosome amplification in tumorigenesis is unclear. Centrosome amplification is not favored in nontransformed cells, with extra centrosomes being spontaneously lost in the absence of selection pressure. It is thus possible that extra centrosomes confer cellular alterations advantageous to tumor progression.
In a study reported in Nature, Godinho and colleagues showed that centrosome amplification induced cell invasion in human mammary epithelial cells. They found that the invasiveness was similar to that induced by ERBB2 and that amplification resulted in enhanced ERBB2-related invasiveness. Overall, the findings suggested that centrosome amplification increases Rac1 activity via increased centrosome microtubule nucleation, resulting in abnormal cell-cell adhesion that promotes invasion.
The investigators concluded, “These findings demonstrate that centrosome amplification, a structural alteration of the cytoskeleton, can promote features of malignant transformation.” ■