p16(INK4a) inactivation is not required to immortalize human mammary epithelial cells.
Using standard culture conditions, primary human mammary epithelial cells (HMECs) undergo a premature, transient growth arrest termed M0 (mortality stage 0) after 10-15 population doublings in vitro. It has been reported that emergence from this growth arrest by the abrogation of p16(INK4a), a cyclin-dependent kinase inhibitor, and expression of the catalytic component of human telomerase (hTERT) are necessary for HMEC immortalization. Here we show that primary HMECs, grown on feeder layers, do not undergo this growth arrest and can be immortalized without abrogating p16. These findings support the concept that the so-called M0 stage represents a cell culture stress-induced growth arrest and that hTERT is sufficient to immortalize HMECs when cultured under adequate conditions.
Herbert
Brittney-Shea
BS
Department of Cell Biology, The University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, Texas, TX 75390-9039, USA.
Wright
Woodring E
WE
Shay
Jerry W
JW
D001940:Breast / Q000166:cytology*; D018929:Cell Culture Techniques / Q000295:instrumentation / Q000379:methods; D002455:Cell Division / Q000187:drug effects; D002471:Cell Transformation, Neoplastic / Q000235:genetics*; D002478:Cells, Cultured / Q000166:cytology; D016922:Cellular Senescence; D018920:Coculture Techniques; D016895:Culture Media, Serum-Free / Q000494:pharmacology; D019941:Cyclin-Dependent Kinase Inhibitor p16 / Q000502:physiology*; D004268:DNA-Binding Proteins; D004847:Epithelial Cells / Q000166:cytology; D005260:Female; D020869:Gene Expression Profiling; D016161:Genes, Retinoblastoma; D019942:Genes, p16; D006801:Humans; D008648:Mesoderm / Q000166:cytology; D010766:Phosphorylation; D010969:Plastics; D011499:Protein Processing, Post-Translational; D016160:Retinoblastoma Protein / Q000378:metabolism; D013312:Stress, Physiological; D019098:Telomerase / Q000502:physiology*; D025803:Tumor Suppressor Protein p14ARF / Q000096:biosynthesis / Q000235:genetics
D016895:Culture Media, Serum-Free; D019941:Cyclin-Dependent Kinase Inhibitor p16; D004268:DNA-Binding Proteins; D010969:Plastics; D016160:Retinoblastoma Protein; D025803:Tumor Suppressor Protein p14ARF; D019098:Telomerase