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

Mullany LK, Fan HY, Liu Z, White LD, Marshall A, Gunaratne P, Anderson ML, Creighton CJ, Xin L, Deavers M, Wong KK, Richards JS - Oncogene (2011)

Bottom Line: 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 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.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX 77030, USA.

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.

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Mutant OSE cells express genes associated with human serous adenocarcinomas in a time-dependent manner. A.) Cytokeratin 8 and E-cadherin-positive OSE cells removed from the ovarian surface exhibit a cobblestone appearance. B.) Expression of genes in RNA samples from whole ovaries and purified OSE cells isolated from ovaries of wild type and Pten;KrasG12D;Amhr2-cre mice at 5 and 10 weeks of age.
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Figure 3: Mutant OSE cells express genes associated with human serous adenocarcinomas in a time-dependent manner. A.) Cytokeratin 8 and E-cadherin-positive OSE cells removed from the ovarian surface exhibit a cobblestone appearance. B.) Expression of genes in RNA samples from whole ovaries and purified OSE cells isolated from ovaries of wild type and Pten;KrasG12D;Amhr2-cre mice at 5 and 10 weeks of age.

Mentions: To determine which of the genes associated with the tumor-bearing ovary at 5 and 10 weeks of age were expressed specifically in purified OSE cells, we isolated OSE cells from ovaries of WT and Pten fl/fl; KrasG12D;Amhr2-Cre mice. The WT and mutant OSE cells (cytokerain 8 positive) were removed from the epithelium by mild-trypsin digestion (Fig.3A, upper panel). The highly purified OSE cells from WT ovaries appear morphologically homogeneous in culture as indicated by the characteristic cuboidal-cell shape (Fig.3A, middle panel) and uniform immunolabeling of cytokeratin 8 and E-cadherin (Fig.3A, lower panel) as would be predicted from their presence in vivo (Fig. 1 and Fig.3A).


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

Mullany LK, Fan HY, Liu Z, White LD, Marshall A, Gunaratne P, Anderson ML, Creighton CJ, Xin L, Deavers M, Wong KK, Richards JS - Oncogene (2011)

Mutant OSE cells express genes associated with human serous adenocarcinomas in a time-dependent manner. A.) Cytokeratin 8 and E-cadherin-positive OSE cells removed from the ovarian surface exhibit a cobblestone appearance. B.) Expression of genes in RNA samples from whole ovaries and purified OSE cells isolated from ovaries of wild type and Pten;KrasG12D;Amhr2-cre mice at 5 and 10 weeks of age.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3139785&req=5

Figure 3: Mutant OSE cells express genes associated with human serous adenocarcinomas in a time-dependent manner. A.) Cytokeratin 8 and E-cadherin-positive OSE cells removed from the ovarian surface exhibit a cobblestone appearance. B.) Expression of genes in RNA samples from whole ovaries and purified OSE cells isolated from ovaries of wild type and Pten;KrasG12D;Amhr2-cre mice at 5 and 10 weeks of age.
Mentions: To determine which of the genes associated with the tumor-bearing ovary at 5 and 10 weeks of age were expressed specifically in purified OSE cells, we isolated OSE cells from ovaries of WT and Pten fl/fl; KrasG12D;Amhr2-Cre mice. The WT and mutant OSE cells (cytokerain 8 positive) were removed from the epithelium by mild-trypsin digestion (Fig.3A, upper panel). The highly purified OSE cells from WT ovaries appear morphologically homogeneous in culture as indicated by the characteristic cuboidal-cell shape (Fig.3A, middle panel) and uniform immunolabeling of cytokeratin 8 and E-cadherin (Fig.3A, lower panel) as would be predicted from their presence in vivo (Fig. 1 and Fig.3A).

Bottom Line: 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 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.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX 77030, USA.

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.

Show MeSH
Related in: MedlinePlus