title: Spontaneous and mutagen-induced transformation of primary cultures of Msh2-/- p53-/- colonocytes.
abstract: Loss of function of mismatch repair (MMR) genes underlies hereditary nonpolyposis colorectal cancer (HNPCC). However, the inability to maintain primary colon epithelial cells in culture has limited the analysis of the contribution of MMR gene defects to colorectal tumorigenesis. We have now established primary cultures of epithelial cells from the colon crypts of Msh2-/- p53-/- double-knockout mice. These cells undergo spontaneous transformation (soft agar colonies and s.c. tumor formation), with a progressively shorter latency as a function of increasing passages in culture. Treatment of early passage cells with the mutagen methylmethane thiosulfonate (MMS) further decreases the transformation latency of Msh2-/- p53-/- cells. Spontaneous transformation of p53-/- colonocytes is only observed using late passage cells, and methylmethane thiosulfonate-treated early passage p53-/- colonocytes do not form tumors when injected into immunodeficient mice. Together, these findings support the pathogenic role of MMR gene inactivation in colorectal tumorigenesis and provide an experimental model for the serial assessment of the molecular phenotype associated with Msh2 deficiency.
authors.affiliation: Department of Microbiology and Immunology, Kimmel Cancer Center, Jefferson Medical College, Philadelphia, Pennsylvania 19107-5541, USA.
authors.forename: C
authors.initials: C
authors.lastname: Sevignani
authors.forename: A
authors.initials: A
authors.lastname: Cranston
authors.forename: R V
authors.initials: RV
authors.lastname: Iozzo
authors.forename: R
authors.initials: R
authors.lastname: Fishel
authors.forename: B
authors.initials: B
authors.lastname: Calabretta
mesh_terms: D000818:Animals; D020137:Base Pair Mismatch; D002455:Cell Division; D002471:Cell Transformation, Neoplastic; D002478:Cells, Cultured; D003106:Colon / Q000187:drug effects / Q000473:pathology*; D003110:Colonic Neoplasms / Q000235:genetics / Q000473:pathology*; D004268:DNA-Binding Proteins; D016158:Genes, p53; D007413:Intestinal Mucosa / Q000187:drug effects / Q000473:pathology* / Q000648:ultrastructure; D008297:Male; D008741:Methyl Methanesulfonate / Q000633:toxicity; D051379:Mice; D008810:Mice, Inbred C57BL; D008815:Mice, Inbred Strains; D018345:Mice, Knockout; D016513:Mice, SCID; D051718:MutS Homolog 2 Protein; D011518:Proto-Oncogene Proteins / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D014183:Transplantation, Heterologous; D016159:Tumor Suppressor Protein p53 / Q000172:deficiency / Q000378:metabolism*
chemical_list: D004268:DNA-Binding Proteins; D011518:Proto-Oncogene Proteins; D016159:Tumor Suppressor Protein p53; D008741:Methyl Methanesulfonate; C497173:Msh2 protein, mouse; D051718:MutS Homolog 2 Protein