Limits...
Mammalian target of rapamycin is a therapeutic target for murine ovarian endometrioid adenocarcinomas with dysregulated Wnt/β-catenin and PTEN.

Tanwar PS, Zhang L, Kaneko-Tarui T, Curley MD, Taketo MM, Rani P, Roberts DJ, Teixeira JM - PLoS ONE (2011)

Bottom Line: Mutations in the WNT and PI3K pathways are frequently observed in the human ovarian endometrioid adenocarcinomas (OEAs).However, the role of WNT/β-catenin and PTEN/AKT signaling in the etiology and/or progression of this disease is currently unclear.These studies demonstrate that rapamycin might be an effective therapeutic for human ovarian endometrioid patients with dysregulated Wnt/β-catenin and Pten/PI3K signaling.

View Article: PubMed Central - PubMed

Affiliation: Vincent Center for Reproductive Biology, Department of Obstetrics, Gynecology, and Reproductive Biology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, United States of America.

ABSTRACT
Despite the fact that epithelial ovarian cancers are the leading cause of death from gynecological cancer, very little is known about the pathophysiology of the disease. Mutations in the WNT and PI3K pathways are frequently observed in the human ovarian endometrioid adenocarcinomas (OEAs). However, the role of WNT/β-catenin and PTEN/AKT signaling in the etiology and/or progression of this disease is currently unclear. In this report we show that mice with a gain-of-function mutation in β-catenin that leads to dysregulated nuclear accumulation of β-catenin expression in the ovarian surface epithelium (OSE) cells develop indolent, undifferentiated tumors with both mesenchymal and epithelial characteristics. Combining dysregulated β-catenin with homozygous deletion of PTEN in the OSE resulted in development of significantly more aggressive tumors, which was correlated with inhibition of p53 expression and cellular senescence. Induced expression of both mTOR kinase, a master regulator of proliferation, and phosphorylation of its downstream target, S6Kinase was also observed in both the indolent and aggressive mouse tumors, as well as in human OEA with nuclear β-catenin accumulation. Ectopic allotransplants of the mouse ovarian tumor cells with a gain-of-function mutation in β-catenin and PTEN deletion developed into tumors with OEA histology, the growth of which were significantly inhibited by oral rapamycin treatment. These studies demonstrate that rapamycin might be an effective therapeutic for human ovarian endometrioid patients with dysregulated Wnt/β-catenin and Pten/PI3K signaling.

Show MeSH

Related in: MedlinePlus

Histological examination of ovarian tumors formed in Amhr2-Cre;Ctnnb1Δ(ex3)/+ mice ovaries.H&E staining of mutant ovaries (Panels A–C). Panels B & C are magnified views of boxed areas in Panel A. Cytokeratin 8 (CK8) immunofluorescence on a serial section (D) of panel C confirming presence of epithelial glands (arrowhead); Bv indicates background fluorescence from a blood vessel. (Panel E) CK8 staining in control ovary marks OSE cells (arrowheads) and oviductal (Ovi) epithelial cells. (Panel F) CK8 expression in a typical small tumor in Amhr2-Cre;Ctnnb1Δ(ex3)/+ ovaries. (Panel G) Vimentin immunofluorescence in control ovaries was present in some stromal cells but not in granulosa cells of follicles (outlined by dotted line, F). In Amhr2-Cre;Ctnnb1Δ(ex3)/+ ovaries (Panel H), vimentin expression was observed throughout the tumors. (Panels I–L) Amh and inhibin-α expression in control (I & K) and mutant (J & L) ovaries. Inhibin-α and Amh expression was present in granulosa cells of the remnant follicles (arrow, demarcated from the tumor by white dotted line) of mutant ovaries but not in tumor areas (indicated with a T). Nuclei are stained with DAPI in Panels D–L. Bars = 50 um.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC3111436&req=5

pone-0020715-g002: Histological examination of ovarian tumors formed in Amhr2-Cre;Ctnnb1Δ(ex3)/+ mice ovaries.H&E staining of mutant ovaries (Panels A–C). Panels B & C are magnified views of boxed areas in Panel A. Cytokeratin 8 (CK8) immunofluorescence on a serial section (D) of panel C confirming presence of epithelial glands (arrowhead); Bv indicates background fluorescence from a blood vessel. (Panel E) CK8 staining in control ovary marks OSE cells (arrowheads) and oviductal (Ovi) epithelial cells. (Panel F) CK8 expression in a typical small tumor in Amhr2-Cre;Ctnnb1Δ(ex3)/+ ovaries. (Panel G) Vimentin immunofluorescence in control ovaries was present in some stromal cells but not in granulosa cells of follicles (outlined by dotted line, F). In Amhr2-Cre;Ctnnb1Δ(ex3)/+ ovaries (Panel H), vimentin expression was observed throughout the tumors. (Panels I–L) Amh and inhibin-α expression in control (I & K) and mutant (J & L) ovaries. Inhibin-α and Amh expression was present in granulosa cells of the remnant follicles (arrow, demarcated from the tumor by white dotted line) of mutant ovaries but not in tumor areas (indicated with a T). Nuclei are stained with DAPI in Panels D–L. Bars = 50 um.

Mentions: Histological examination of adult mutant ovaries (≥12-wks of age) revealed the presence of pre-tumoral nests of cells in all the ovaries examined in this study (n = 10) (Fig. S1C–E). The cancerous cells were also present between the ovarian bursa and OSE (Fig. S1C–E). Nuclear β-catenin was observed in these pre-tumoral nests, indicating that these lesions were derived from Amhr2-cre expressing cells (Fig. S1F). Ovaries from age-matched control mice appeared morphologically normal (Fig. S1A & B). Even though pretumoral lesions were present in the ovaries of all young Amhr2-Cre;Ctnnb1Δ(ex3)/+ mice, advanced tumor development only occurred in approximately 50% of mice by the age of 8-month to 1-year (Fig. 2). While the majority of the tumors were undifferentiated (Fig. 2A & B), epithelial glands, which are characteristic of ovarian endometrioid adenocarcinomas, were observed in 5/6 mice examined (Fig. 2C). Immunostaining with cytokeratin 8 (CK8), an epithelial cell specific marker, confirmed the presence of epithelial glands in these tumors (Fig. 2D). CK8-specific staining was also observed in early pretumoral lesions, as well as in undifferentiated tumors, indicative of the epithelial cell origin of these tumors (Fig. 2F). In control ovaries, CK8 staining was only observed in the ovarian surface epithelium and oviductal epithelial cells (Fig. 2E). Because the less differentiated areas of Amhr2-Cre;Ctnnb1Δ(ex3)/+ tumors showed weak staining for CK8 and had a more spindle shape morphology, we examined the expression of vimentin, a mesenchymal marker. We observed strong positive staining for vimentin in less differentiated areas of pretumoral lesions and in fully-grown tumors, suggesting that cancerous cells undergo epithelial mesenchymal transition (EMT) in these tumors (Fig. 2H). Vimentin staining was observed in stromal but not in granulosa cells of the control ovaries (Fig. 2G).


Mammalian target of rapamycin is a therapeutic target for murine ovarian endometrioid adenocarcinomas with dysregulated Wnt/β-catenin and PTEN.

Tanwar PS, Zhang L, Kaneko-Tarui T, Curley MD, Taketo MM, Rani P, Roberts DJ, Teixeira JM - PLoS ONE (2011)

Histological examination of ovarian tumors formed in Amhr2-Cre;Ctnnb1Δ(ex3)/+ mice ovaries.H&E staining of mutant ovaries (Panels A–C). Panels B & C are magnified views of boxed areas in Panel A. Cytokeratin 8 (CK8) immunofluorescence on a serial section (D) of panel C confirming presence of epithelial glands (arrowhead); Bv indicates background fluorescence from a blood vessel. (Panel E) CK8 staining in control ovary marks OSE cells (arrowheads) and oviductal (Ovi) epithelial cells. (Panel F) CK8 expression in a typical small tumor in Amhr2-Cre;Ctnnb1Δ(ex3)/+ ovaries. (Panel G) Vimentin immunofluorescence in control ovaries was present in some stromal cells but not in granulosa cells of follicles (outlined by dotted line, F). In Amhr2-Cre;Ctnnb1Δ(ex3)/+ ovaries (Panel H), vimentin expression was observed throughout the tumors. (Panels I–L) Amh and inhibin-α expression in control (I & K) and mutant (J & L) ovaries. Inhibin-α and Amh expression was present in granulosa cells of the remnant follicles (arrow, demarcated from the tumor by white dotted line) of mutant ovaries but not in tumor areas (indicated with a T). Nuclei are stained with DAPI in Panels D–L. Bars = 50 um.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3111436&req=5

pone-0020715-g002: Histological examination of ovarian tumors formed in Amhr2-Cre;Ctnnb1Δ(ex3)/+ mice ovaries.H&E staining of mutant ovaries (Panels A–C). Panels B & C are magnified views of boxed areas in Panel A. Cytokeratin 8 (CK8) immunofluorescence on a serial section (D) of panel C confirming presence of epithelial glands (arrowhead); Bv indicates background fluorescence from a blood vessel. (Panel E) CK8 staining in control ovary marks OSE cells (arrowheads) and oviductal (Ovi) epithelial cells. (Panel F) CK8 expression in a typical small tumor in Amhr2-Cre;Ctnnb1Δ(ex3)/+ ovaries. (Panel G) Vimentin immunofluorescence in control ovaries was present in some stromal cells but not in granulosa cells of follicles (outlined by dotted line, F). In Amhr2-Cre;Ctnnb1Δ(ex3)/+ ovaries (Panel H), vimentin expression was observed throughout the tumors. (Panels I–L) Amh and inhibin-α expression in control (I & K) and mutant (J & L) ovaries. Inhibin-α and Amh expression was present in granulosa cells of the remnant follicles (arrow, demarcated from the tumor by white dotted line) of mutant ovaries but not in tumor areas (indicated with a T). Nuclei are stained with DAPI in Panels D–L. Bars = 50 um.
Mentions: Histological examination of adult mutant ovaries (≥12-wks of age) revealed the presence of pre-tumoral nests of cells in all the ovaries examined in this study (n = 10) (Fig. S1C–E). The cancerous cells were also present between the ovarian bursa and OSE (Fig. S1C–E). Nuclear β-catenin was observed in these pre-tumoral nests, indicating that these lesions were derived from Amhr2-cre expressing cells (Fig. S1F). Ovaries from age-matched control mice appeared morphologically normal (Fig. S1A & B). Even though pretumoral lesions were present in the ovaries of all young Amhr2-Cre;Ctnnb1Δ(ex3)/+ mice, advanced tumor development only occurred in approximately 50% of mice by the age of 8-month to 1-year (Fig. 2). While the majority of the tumors were undifferentiated (Fig. 2A & B), epithelial glands, which are characteristic of ovarian endometrioid adenocarcinomas, were observed in 5/6 mice examined (Fig. 2C). Immunostaining with cytokeratin 8 (CK8), an epithelial cell specific marker, confirmed the presence of epithelial glands in these tumors (Fig. 2D). CK8-specific staining was also observed in early pretumoral lesions, as well as in undifferentiated tumors, indicative of the epithelial cell origin of these tumors (Fig. 2F). In control ovaries, CK8 staining was only observed in the ovarian surface epithelium and oviductal epithelial cells (Fig. 2E). Because the less differentiated areas of Amhr2-Cre;Ctnnb1Δ(ex3)/+ tumors showed weak staining for CK8 and had a more spindle shape morphology, we examined the expression of vimentin, a mesenchymal marker. We observed strong positive staining for vimentin in less differentiated areas of pretumoral lesions and in fully-grown tumors, suggesting that cancerous cells undergo epithelial mesenchymal transition (EMT) in these tumors (Fig. 2H). Vimentin staining was observed in stromal but not in granulosa cells of the control ovaries (Fig. 2G).

Bottom Line: Mutations in the WNT and PI3K pathways are frequently observed in the human ovarian endometrioid adenocarcinomas (OEAs).However, the role of WNT/β-catenin and PTEN/AKT signaling in the etiology and/or progression of this disease is currently unclear.These studies demonstrate that rapamycin might be an effective therapeutic for human ovarian endometrioid patients with dysregulated Wnt/β-catenin and Pten/PI3K signaling.

View Article: PubMed Central - PubMed

Affiliation: Vincent Center for Reproductive Biology, Department of Obstetrics, Gynecology, and Reproductive Biology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, United States of America.

ABSTRACT
Despite the fact that epithelial ovarian cancers are the leading cause of death from gynecological cancer, very little is known about the pathophysiology of the disease. Mutations in the WNT and PI3K pathways are frequently observed in the human ovarian endometrioid adenocarcinomas (OEAs). However, the role of WNT/β-catenin and PTEN/AKT signaling in the etiology and/or progression of this disease is currently unclear. In this report we show that mice with a gain-of-function mutation in β-catenin that leads to dysregulated nuclear accumulation of β-catenin expression in the ovarian surface epithelium (OSE) cells develop indolent, undifferentiated tumors with both mesenchymal and epithelial characteristics. Combining dysregulated β-catenin with homozygous deletion of PTEN in the OSE resulted in development of significantly more aggressive tumors, which was correlated with inhibition of p53 expression and cellular senescence. Induced expression of both mTOR kinase, a master regulator of proliferation, and phosphorylation of its downstream target, S6Kinase was also observed in both the indolent and aggressive mouse tumors, as well as in human OEA with nuclear β-catenin accumulation. Ectopic allotransplants of the mouse ovarian tumor cells with a gain-of-function mutation in β-catenin and PTEN deletion developed into tumors with OEA histology, the growth of which were significantly inhibited by oral rapamycin treatment. These studies demonstrate that rapamycin might be an effective therapeutic for human ovarian endometrioid patients with dysregulated Wnt/β-catenin and Pten/PI3K signaling.

Show MeSH
Related in: MedlinePlus