title: Isogenic human mammary epithelial cell lines: novel tools for target identification and validation. Comprehensive characterization of an isogenic human mammary epithelial cell model provides evidence for epithelial-mesenchymal transition.
abstract: Tumorigenesis is a multi-step process involving several consecutive genetic alterations resulting in loss of genomic stability and deregulated signal transduction pathways. To study these deregulated processes in vitro, typically established cancer cell lines derived from primary tumors, ascites, or from metastases are used. However, these cancer cell lines reflect only late stages of the tumorigenic process. To better understand the consequences of the sequential genetic alterations in an in vitro model system, we applied consecutive immortalization and transformation of primary human mammary epithelial cells (HMECs) combining shRNA-mediated knockdown of tumor suppressor genes and overexpression of oncogenes. Thereby, we developed a panel of isogenic HMEC-derived cell lines reflecting the multi-step process of tumorigenesis. The immortalized cell lines have a normal epithelial morphology and proliferate indefinitely and anchorage-dependently. In contrast, the transformed cells exhibit mesenchymal-like morphological changes and strong colony-forming activity in soft agar. SNP array analysis showed that none of the cell lines displayed gross chromosomal aberrations in 80 % of the chromosomes. However, massive changes were observed in some chromosomes of the transformed cells indicating that the transformed phenotype is characterized by chromosomal alterations. The isogenic immortalized and transformed cells described here provide a powerful tool for the in vitro validation of target genes for cancer therapy.
authors.affiliation: Global Drug Discovery, Global R&D Information, Bayer Healthcare Pharmaceuticals, Bayer Pharma AG, 42096, Wuppertal, Germany. ulrike.ulbricht@bayer.com
authors.forename: Ulrike
authors.initials: U
authors.lastname: Ulbricht
authors.forename: Anette
authors.initials: A
authors.lastname: Sommer
authors.forename: Georg
authors.initials: G
authors.lastname: Beckmann
authors.forename: Manuel
authors.initials: M
authors.lastname: Lutzenberger
authors.forename: Henrik
authors.initials: H
authors.lastname: Seidel
authors.forename: Bertolt
authors.initials: B
authors.lastname: Kreft
authors.forename: Luisella
authors.initials: L
authors.lastname: Toschi
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology; D017209:Apoptosis; D002460:Cell Line; D049109:Cell Proliferation; D048430:Cell Shape; D002470:Cell Survival / Q000187:drug effects; D056915:DNA Copy Number Variations; D004354:Drug Screening Assays, Antitumor; D004847:Epithelial Cells / Q000502:physiology*; D058750:Epithelial-Mesenchymal Transition; D005260:Female; D015870:Gene Expression; D015972:Gene Expression Regulation, Neoplastic; D055785:Gene Knockdown Techniques; D053263:Gene Regulatory Networks; D006801:Humans; D006918:Hydroxyurea / Q000494:pharmacology; D042361:Mammary Glands, Human / Q000166:cytology*; D020411:Oligonucleotide Array Sequence Analysis; D051059:PTEN Phosphohydrolase / Q000235:genetics / Q000378:metabolism; D020641:Polymorphism, Single Nucleotide; D016271:Proto-Oncogene Proteins c-myc / Q000235:genetics / Q000378:metabolism; D016283:Proto-Oncogene Proteins p21(ras) / Q000235:genetics; D034741:RNA, Small Interfering / Q000235:genetics; D015398:Signal Transduction / Q000187:drug effects; D019098:Telomerase / Q000378:metabolism; D059467:Transcriptome; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism
chemical_list: D000970:Antineoplastic Agents; C489427:MYC protein, human; D016271:Proto-Oncogene Proteins c-myc; D034741:RNA, Small Interfering; C495901:TP53 protein, human; D016159:Tumor Suppressor Protein p53; C509186:TERT protein, human; D019098:Telomerase; D051059:PTEN Phosphohydrolase; C494929:PTEN protein, human; C501009:HRAS protein, human; D016283:Proto-Oncogene Proteins p21(ras); D006918:Hydroxyurea