Studies on the supernumerary centrioles in the breast cancer cell lines

Abstract

Centrosomes are major microtubule organizer in animal cells. It is critical to maintain two centrosomes in a single cell since they function as spindle poles to pull a set of chromosomes into two daughter cells. However, deregulations in centrosome numbers are frequently observed in cancer cells. Here, I investigated generation of the supernumerary centrioles in selected breast cancer cells. The number of centrioles at specific stages of the cell cycle was determined with the coimmunostaining analyses using the BrdU and centrin-2 antibodies. The results showed that supernumerary centrioles are maintained at specific subset of the breast cancer cell populations. The proportions of the cells with supernumerary centrioles were not identical during the cell cycle. In case of MDA-MB-231 cells, proportion of the cells with supernumerary centrioles were maintained to 20% throughout the cell cycle. However, in case of Hs578t cells, supernumerary centrioles were detected in 5% of the S phase cells, but in 50% of the M phase cells. I also detected premature separation of centrioles in Hs578t cells at mitosis. These results suggest that supernumerary centrioles may be generated at specific cell cycle stages, possibly following distinct amplifying mechanisms. The breast cancer cell lines may adopt their own mechanisms for amplifying their centrioles.