Smad signaling is required for maintenance of epigenetic gene silencing during breast cancer progression

In this study, we took advantage of a previously established breast cancer progression cell line model system, which consists of a parental MCF10A (MI) spontaneously immortalized mammary epithelial cell line and two of its derivatives: 1) MCF10ATk.cl2 (MII), a MCF10A H-Ras transformed cell line and 3) MCF10CA1h (MIII), derived from a xenograft of the MII cells in nude mice that progressed to carcinoma (1, 2). These cell lines were previously reported to exhibit distinct tumorigenic properties when re-implanted in nude mice; MI is non-tumorigenic, MII forms benign hyperplastic lesions and MIII forms low-grade, well differentiated carcinomas (2, 3). The advantage of this system is that these cell lines were derived from a common genetic background (MCF10A) and accumulated distinct genetic/epigenetic alterations in vivo enabling them to acquire a range of non-tumorigenic to carcinogenic properties. Our initial studies showed that MIII cells, but not MI or MII, exhibit an EMT phenotype, promoter DNA hypermethylation of epithelial genes and highly invasive properties in vitro.

9

Papageorgis P, Lambert AW, Ozturk S, Gao F, Pan H, Manne U, Alekseyev YO, Thiagalingam A, Abdolmaleky HM, Lenburg M, Thiagalingam S