Molecular and functional characteristics of ovarian surface epithelial cells transformed by KrasG12D and loss of Pten in a mouse model in vivo

Oncogene. 2011 Aug 11;30(32):3522-36. doi: 10.1038/onc.2011.70. Epub 2011 Mar 21.

Abstract

Ovarian cancer is a complex and deadly disease that remains difficult to detect at an early curable stage. Furthermore, although some oncogenic (Kras, Pten/PI3K and Trp53) pathways that are frequently mutated, deleted or amplified in ovarian cancer are known, how these pathways initiate and drive specific morphological phenotypes and tumor outcomes remain unclear. We recently generated Pten(fl/fl); Kras(G12D); Amhr2-Cre mice to disrupt the Pten gene and express a stable mutant form of Kras(G12D) in ovarian surface epithelial (OSE) cells. On the basis of histopathologic criteria, the mutant mice developed low-grade ovarian serous papillary adenocarcinomas at an early age and with 100% penetrance. This highly reproducible phenotype provides the first mouse model in which to study this ovarian cancer subtype. OSE cells isolated from ovaries of mutant mice at 5 and 10 weeks of age exhibit temporal changes in the expression of specific Mullerian epithelial marker genes, grow in soft agar and develop ectopic invasive tumors in recipient mice, indicating that the cells are transformed. Gene profiling identified specific mRNAs and microRNAs differentially expressed in purified OSE cells derived from tumors of the mutant mice compared with wild-type OSE cells. Mapping of transcripts or genes between the mouse OSE mutant data sets, the Kras signature from human cancer cell lines and the human ovarian tumor array data sets, documented significant overlap, indicating that KRAS is a key driver of OSE transformation in this context. Two key hallmarks of the mutant OSE cells in these mice are the elevated expression of the tumor-suppressor Trp53 (p53) and its microRNA target, miR-34a-c. We propose that elevated TRP53 and miR-34a-c may exert negatively regulatory effects that reduce the proliferative potential of OSE cells leading to the low-grade serous adenocarcinoma phenotype.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Biomarkers, Tumor / genetics
  • Biomarkers, Tumor / metabolism
  • Blotting, Western
  • Carcinoma, Ovarian Epithelial
  • Cell Line, Transformed
  • Cell Transformation, Neoplastic / genetics*
  • Cells, Cultured
  • Cystadenocarcinoma, Serous / genetics
  • Cystadenocarcinoma, Serous / metabolism
  • Cystadenocarcinoma, Serous / pathology
  • Disease Models, Animal
  • Epithelial Cells / metabolism*
  • Female
  • Gene Expression Profiling
  • Gene Expression Regulation, Neoplastic
  • Humans
  • Mice
  • Mice, Knockout
  • MicroRNAs / genetics
  • Neoplasm Transplantation
  • Neoplasms, Glandular and Epithelial / genetics
  • Neoplasms, Glandular and Epithelial / metabolism
  • Neoplasms, Glandular and Epithelial / pathology
  • Oligonucleotide Array Sequence Analysis
  • Ovarian Neoplasms / genetics
  • Ovarian Neoplasms / metabolism
  • Ovarian Neoplasms / pathology
  • Ovary / cytology
  • PTEN Phosphohydrolase / genetics*
  • PTEN Phosphohydrolase / metabolism
  • Proto-Oncogene Proteins p21(ras) / genetics*
  • Proto-Oncogene Proteins p21(ras) / metabolism
  • Reverse Transcriptase Polymerase Chain Reaction
  • Tumor Suppressor Protein p53 / genetics

Substances

  • Biomarkers, Tumor
  • MIRN34a microRNA, mouse
  • MicroRNAs
  • Tumor Suppressor Protein p53
  • PTEN Phosphohydrolase
  • Pten protein, mouse
  • Hras protein, mouse
  • Proto-Oncogene Proteins p21(ras)