Cell culture and senescence in uterine fibroids

The in vitro growth of cells from uterine fibroids is characterized by an early onset of senescence. Often, an even lower growth potential than that of matching myometrial cells is noted. Also, the tremendous differences in the expression of the high mobility group protein HMGA2 seen when comparing fibroids of different genetic subtypes are surprisingly not reflected by significant differences in their growth potential in vitro. We aimed to evaluate possible changes of the HMGA2 expression level between the native tissue and cell cultures, so we performed quantitative real-time polymerase chain reaction studies that revealed a marked decrease of the HMGA2 mRNA in culture in those cases with overexpression of HMGA2. In the two cases initially showing the highest expression, it decreased by approximately 97%. Associated with the decrease of HMGA2 was a clearly increased expression of the senescence-associated p19Arf. Together, these findings explain the similar behavior of cell cultures from fibroids of different genetic subgroups and may also offer an explanation for the early onset of in vitro senescence in these cell cultures.