Chromosome 17p13.2 Transfer Reverts Transformation Phenotypes and Fas-Mediated Apoptosis in Breast Epithelial Cells

Transformation of the human breast epithelial cells (HBEC) MCF-10F with the carcinogen benz(a)pyrene (BP) into BP1-E cells resulted in the loss of the chromosome 17 p13.2 locus (D17S796 marker) and formation of colonies in agar-methocel (colony efficiency (CE)), loss of ductulogenic capacity in collagen matrix, and resistance to anti-Fas monoclonal antibody (Mab)-induced apoptosis. For testing the role of that specific region of chromosome 17 in the expression of transformation phenotypes, we transferred chromosome 17 from mouse fibroblast donors to BP1-E cells. Chromosome 11 was used as negative control. After G418 selection, nine clones each were randomly selected from BP1-E-11neo and BP1-E-17neo hybrids, respectively, and tested for the presence of the donor chromosomes by fluorescent in situ hybridization and polymerase chain reaction-based restriction fragment length polymorphism (PCR-RFLP) analyses. Sensitivity to Fas Mab-induced apoptosis and evaluation of transformation phenotype expression were tested in MCF-10F, BP1-E, and nine BP1-E-11neo and BP1-E-17neo clones each. Six BP1-E-17neo clones exhibited a reversion of transformation phenotypes and a dose dependent sensitivity to Fas Mab-induced apoptosis, behaving similarly to MCF-1 OF cells. All BP1-E-11neo, and three BP1-E-17neo cell clones, like BP1-E cells, retained a high CE, loss of ductulogenic capacity, and were resistant to all Fas Mab doses tested. Genomic analysis revealed that those six BP1-E-17neo clones that were Fas-sensitive and reverted their transformed phenotypes had retained the 17p13. 2 (D17S796 marker) region, whereas it was absent in all resistant clones, indicating that the expression of transformation phenotypes and the sensitivity of the cells to Fas-mediated apoptosis were under the control of genes located in this region.