Induction of multiple microtubule-organizing centers, multipolar spindles and multipolar division in cultured V79 cells exposed to diethylstilbestrol, estradiol-17β and bisphenol A

Abstract

Inducibility of multipolar spindles and multipolar division by diethylstilbestrol (DES) and estradiol-17β (E2) was investigated in terms of the mechanism of induction of aneuploidy by the estrogens. DES, E2 and bisphenol A (Bp-A), a structural analogue of DES, caused mitotic arrest and aberrant spindles, such as tripolar and multipolar spindles, in a concentration-dependent manner. γ-Tubulin, a well-characterized component of microtubule-organizing centers (MTOCs), was co-localized with the aberrant spindles induced by estrogens and Bp-A. The number of γ-tubulin signals in the mitotic cells coincided with that of the aberrant spindles and rose with an increasing concentration of the chemicals. The incidence and location of γ-tubulin in interphase cells were not influenced by the chemicals. These results suggest that multiple MT nucleating sites were induced by the estrogens and Bp-A during the transition from interphase to the mitotic phase. DES, E2 and Bp-A induced multipolar division in a concentration-dependent process associated with the induction of aneuploidy.