Limits...
STAT3 regulated ARF expression suppresses prostate cancer metastasis.

Pencik J, Schlederer M, Gruber W, Unger C, Walker SM, Chalaris A, Marié IJ, Hassler MR, Javaheri T, Aksoy O, Blayney JK, Prutsch N, Skucha A, Herac M, Krämer OH, Mazal P, Grebien F, Egger G, Poli V, Mikulits W, Eferl R, Esterbauer H, Kennedy R, Fend F, Scharpf M, Braun M, Perner S, Levy DE, Malcolm T, Turner SD, Haitel A, Susani M, Moazzami A, Rose-John S, Aberger F, Merkel O, Moriggl R, Culig Z, Dolznig H, Kenner L - Nat Commun (2015)

Bottom Line: However, targeting of the IL-6/STAT3 axis in PCa patients has failed to provide therapeutic benefit.STAT3 and CDKN2A deletions co-occurred with high frequency in PCa metastases.Our findings challenge the current discussion on therapeutic benefit or risk of IL-6/STAT3 inhibition.

View Article: PubMed Central - PubMed

Affiliation: Ludwig Boltzmann Institute for Cancer Research, Waehringerstrasse 13A, 1090 Vienna, Austria.

ABSTRACT
Prostate cancer (PCa) is the most prevalent cancer in men. Hyperactive STAT3 is thought to be oncogenic in PCa. However, targeting of the IL-6/STAT3 axis in PCa patients has failed to provide therapeutic benefit. Here we show that genetic inactivation of Stat3 or IL-6 signalling in a Pten-deficient PCa mouse model accelerates cancer progression leading to metastasis. Mechanistically, we identify p19(ARF) as a direct Stat3 target. Loss of Stat3 signalling disrupts the ARF-Mdm2-p53 tumour suppressor axis bypassing senescence. Strikingly, we also identify STAT3 and CDKN2A mutations in primary human PCa. STAT3 and CDKN2A deletions co-occurred with high frequency in PCa metastases. In accordance, loss of STAT3 and p14(ARF) expression in patient tumours correlates with increased risk of disease recurrence and metastatic PCa. Thus, STAT3 and ARF may be prognostic markers to stratify high from low risk PCa patients. Our findings challenge the current discussion on therapeutic benefit or risk of IL-6/STAT3 inhibition.

No MeSH data available.


Related in: MedlinePlus

Genetic deletion of Stat3 and Pten triggers progressive prostate tumorigenesis and lethal disease.(a) Comparison of prostates from WT and Ptenpc−/− mice at 19 weeks of age using immunohistochemical (IHC) analysis of pY-Stat3, pS-Stat3 and Stat3. Scale bars, 100 μm. (b) Protein expression analysis of pY-Stat3, pS-Stat3, Stat3, p-Akt, Akt and β-actin with western blots in 19-week-old prostates from WT and Ptenpc−/− mice. (c) Gross anatomy of representative prostates isolated at 52 weeks of age from WT, Stat3pc−/−, Ptenpc−/− and Ptenpc−/−Stat3pc−/− mice. Scale bars, 10 mm. (d) Prostate weights of 52-week-old WT, Stat3pc−/−, Ptenpc−/− and Ptenpc−/−Stat3pc−/− mice (n=24). Mean values are shown; Data were analysed by one-way analysis of variance with Tukey's multiple comparison test; error bars: s.d. (e) IHC analyses of prostates from 19-week-old WT, Stat3pc−/−, Ptenpc−/− and Ptenpc−/−Stat3pc−/− mice stained for Ki-67 and cleaved caspase 3 (CC3). Scale bars, 100 μm; insets: × 600 magnification. (f) Quantification of cells positive for Ki-67 and CC3 using HistoQuest software (n=5). Data were analysed by Student's t-test and are shown as mean±s.d. (g) Kaplan–Meier cumulative survival analysis revealed a significant (P<0.0001; log-rank test) decrease in lifespan of Ptenpc−/−Stat3pc−/− compared with Ptenpc−/− mice (n=49); WT and Stat3pc−/− mice served as controls.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4525303&req=5

f1: Genetic deletion of Stat3 and Pten triggers progressive prostate tumorigenesis and lethal disease.(a) Comparison of prostates from WT and Ptenpc−/− mice at 19 weeks of age using immunohistochemical (IHC) analysis of pY-Stat3, pS-Stat3 and Stat3. Scale bars, 100 μm. (b) Protein expression analysis of pY-Stat3, pS-Stat3, Stat3, p-Akt, Akt and β-actin with western blots in 19-week-old prostates from WT and Ptenpc−/− mice. (c) Gross anatomy of representative prostates isolated at 52 weeks of age from WT, Stat3pc−/−, Ptenpc−/− and Ptenpc−/−Stat3pc−/− mice. Scale bars, 10 mm. (d) Prostate weights of 52-week-old WT, Stat3pc−/−, Ptenpc−/− and Ptenpc−/−Stat3pc−/− mice (n=24). Mean values are shown; Data were analysed by one-way analysis of variance with Tukey's multiple comparison test; error bars: s.d. (e) IHC analyses of prostates from 19-week-old WT, Stat3pc−/−, Ptenpc−/− and Ptenpc−/−Stat3pc−/− mice stained for Ki-67 and cleaved caspase 3 (CC3). Scale bars, 100 μm; insets: × 600 magnification. (f) Quantification of cells positive for Ki-67 and CC3 using HistoQuest software (n=5). Data were analysed by Student's t-test and are shown as mean±s.d. (g) Kaplan–Meier cumulative survival analysis revealed a significant (P<0.0001; log-rank test) decrease in lifespan of Ptenpc−/−Stat3pc−/− compared with Ptenpc−/− mice (n=49); WT and Stat3pc−/− mice served as controls.

Mentions: To study the role of PTEN and STAT3 in PCa development, we took advantage of mice with conditional loss of Pten in the prostate epithelium (Pb-Cre4 Ptenfl/fl) hereafter referred to as Ptenpc−/− (ref. 13). Stat3 protein levels were markedly induced in Ptenpc−/− compared with wild-type (WT) prostate epithelium (Fig. 1a,b). Ptenpc−/− tumours showed strong Akt Ser473 phosphorylation and, unexpectedly, Stat3 Tyr705 and Ser727 phosphorylation suggesting maximal transcriptional activity of Stat3 (Fig. 1a,b and Supplementary Fig. 1a). In addition, we observed an increase in IL-6Rα levels in tumour cells and soluble IL-6R serum levels (Supplementary Fig. 1a–c) as well as increased Stat3, IL-6Rα and IL-6 mRNA levels (Supplementary Fig. 1d) in Ptenpc−/− PCa compared with WT controls. To prove that loss of Stat3 signalling influences PCa formation, we generated mice with concomitant loss of Pten and Stat3 in prostate epithelial cells. Prostate-specific deletion of Pten and Stat3 was confirmed by PCR (Supplementary Fig. 2a). Immunohistochemistry (IHC) analysis confirmed loss of pY-Stat3 and Stat3 in Ptenpc−/−Stat3pc−/− tumour cells (Supplementary Fig. 2b), while still being present in stromal cells (Supplementary Fig. 2c). Surprisingly, and in sharp contrast to the oncogenic role of Stat3 in many cancers1415, Ptenpc−/−Stat3pc−/− mice showed accelerated PCa formation with up to sixfold increase in tumour weight compared with Ptenpc−/− tumours at different stages of PCa development (Fig. 1c,d and Supplementary Fig. 2d,e). Ptenpc−/−Stat3pc−/− tumours showed increased numbers of Ki-67 positive (Ki-67+) proliferating cells and reduced numbers of cleaved caspase 3 positive (CC3+) apoptotic cells compared with Ptenpc−/− prostates (Fig. 1e,f).


STAT3 regulated ARF expression suppresses prostate cancer metastasis.

Pencik J, Schlederer M, Gruber W, Unger C, Walker SM, Chalaris A, Marié IJ, Hassler MR, Javaheri T, Aksoy O, Blayney JK, Prutsch N, Skucha A, Herac M, Krämer OH, Mazal P, Grebien F, Egger G, Poli V, Mikulits W, Eferl R, Esterbauer H, Kennedy R, Fend F, Scharpf M, Braun M, Perner S, Levy DE, Malcolm T, Turner SD, Haitel A, Susani M, Moazzami A, Rose-John S, Aberger F, Merkel O, Moriggl R, Culig Z, Dolznig H, Kenner L - Nat Commun (2015)

Genetic deletion of Stat3 and Pten triggers progressive prostate tumorigenesis and lethal disease.(a) Comparison of prostates from WT and Ptenpc−/− mice at 19 weeks of age using immunohistochemical (IHC) analysis of pY-Stat3, pS-Stat3 and Stat3. Scale bars, 100 μm. (b) Protein expression analysis of pY-Stat3, pS-Stat3, Stat3, p-Akt, Akt and β-actin with western blots in 19-week-old prostates from WT and Ptenpc−/− mice. (c) Gross anatomy of representative prostates isolated at 52 weeks of age from WT, Stat3pc−/−, Ptenpc−/− and Ptenpc−/−Stat3pc−/− mice. Scale bars, 10 mm. (d) Prostate weights of 52-week-old WT, Stat3pc−/−, Ptenpc−/− and Ptenpc−/−Stat3pc−/− mice (n=24). Mean values are shown; Data were analysed by one-way analysis of variance with Tukey's multiple comparison test; error bars: s.d. (e) IHC analyses of prostates from 19-week-old WT, Stat3pc−/−, Ptenpc−/− and Ptenpc−/−Stat3pc−/− mice stained for Ki-67 and cleaved caspase 3 (CC3). Scale bars, 100 μm; insets: × 600 magnification. (f) Quantification of cells positive for Ki-67 and CC3 using HistoQuest software (n=5). Data were analysed by Student's t-test and are shown as mean±s.d. (g) Kaplan–Meier cumulative survival analysis revealed a significant (P<0.0001; log-rank test) decrease in lifespan of Ptenpc−/−Stat3pc−/− compared with Ptenpc−/− mice (n=49); WT and Stat3pc−/− mice served as controls.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4525303&req=5

f1: Genetic deletion of Stat3 and Pten triggers progressive prostate tumorigenesis and lethal disease.(a) Comparison of prostates from WT and Ptenpc−/− mice at 19 weeks of age using immunohistochemical (IHC) analysis of pY-Stat3, pS-Stat3 and Stat3. Scale bars, 100 μm. (b) Protein expression analysis of pY-Stat3, pS-Stat3, Stat3, p-Akt, Akt and β-actin with western blots in 19-week-old prostates from WT and Ptenpc−/− mice. (c) Gross anatomy of representative prostates isolated at 52 weeks of age from WT, Stat3pc−/−, Ptenpc−/− and Ptenpc−/−Stat3pc−/− mice. Scale bars, 10 mm. (d) Prostate weights of 52-week-old WT, Stat3pc−/−, Ptenpc−/− and Ptenpc−/−Stat3pc−/− mice (n=24). Mean values are shown; Data were analysed by one-way analysis of variance with Tukey's multiple comparison test; error bars: s.d. (e) IHC analyses of prostates from 19-week-old WT, Stat3pc−/−, Ptenpc−/− and Ptenpc−/−Stat3pc−/− mice stained for Ki-67 and cleaved caspase 3 (CC3). Scale bars, 100 μm; insets: × 600 magnification. (f) Quantification of cells positive for Ki-67 and CC3 using HistoQuest software (n=5). Data were analysed by Student's t-test and are shown as mean±s.d. (g) Kaplan–Meier cumulative survival analysis revealed a significant (P<0.0001; log-rank test) decrease in lifespan of Ptenpc−/−Stat3pc−/− compared with Ptenpc−/− mice (n=49); WT and Stat3pc−/− mice served as controls.
Mentions: To study the role of PTEN and STAT3 in PCa development, we took advantage of mice with conditional loss of Pten in the prostate epithelium (Pb-Cre4 Ptenfl/fl) hereafter referred to as Ptenpc−/− (ref. 13). Stat3 protein levels were markedly induced in Ptenpc−/− compared with wild-type (WT) prostate epithelium (Fig. 1a,b). Ptenpc−/− tumours showed strong Akt Ser473 phosphorylation and, unexpectedly, Stat3 Tyr705 and Ser727 phosphorylation suggesting maximal transcriptional activity of Stat3 (Fig. 1a,b and Supplementary Fig. 1a). In addition, we observed an increase in IL-6Rα levels in tumour cells and soluble IL-6R serum levels (Supplementary Fig. 1a–c) as well as increased Stat3, IL-6Rα and IL-6 mRNA levels (Supplementary Fig. 1d) in Ptenpc−/− PCa compared with WT controls. To prove that loss of Stat3 signalling influences PCa formation, we generated mice with concomitant loss of Pten and Stat3 in prostate epithelial cells. Prostate-specific deletion of Pten and Stat3 was confirmed by PCR (Supplementary Fig. 2a). Immunohistochemistry (IHC) analysis confirmed loss of pY-Stat3 and Stat3 in Ptenpc−/−Stat3pc−/− tumour cells (Supplementary Fig. 2b), while still being present in stromal cells (Supplementary Fig. 2c). Surprisingly, and in sharp contrast to the oncogenic role of Stat3 in many cancers1415, Ptenpc−/−Stat3pc−/− mice showed accelerated PCa formation with up to sixfold increase in tumour weight compared with Ptenpc−/− tumours at different stages of PCa development (Fig. 1c,d and Supplementary Fig. 2d,e). Ptenpc−/−Stat3pc−/− tumours showed increased numbers of Ki-67 positive (Ki-67+) proliferating cells and reduced numbers of cleaved caspase 3 positive (CC3+) apoptotic cells compared with Ptenpc−/− prostates (Fig. 1e,f).

Bottom Line: However, targeting of the IL-6/STAT3 axis in PCa patients has failed to provide therapeutic benefit.STAT3 and CDKN2A deletions co-occurred with high frequency in PCa metastases.Our findings challenge the current discussion on therapeutic benefit or risk of IL-6/STAT3 inhibition.

View Article: PubMed Central - PubMed

Affiliation: Ludwig Boltzmann Institute for Cancer Research, Waehringerstrasse 13A, 1090 Vienna, Austria.

ABSTRACT
Prostate cancer (PCa) is the most prevalent cancer in men. Hyperactive STAT3 is thought to be oncogenic in PCa. However, targeting of the IL-6/STAT3 axis in PCa patients has failed to provide therapeutic benefit. Here we show that genetic inactivation of Stat3 or IL-6 signalling in a Pten-deficient PCa mouse model accelerates cancer progression leading to metastasis. Mechanistically, we identify p19(ARF) as a direct Stat3 target. Loss of Stat3 signalling disrupts the ARF-Mdm2-p53 tumour suppressor axis bypassing senescence. Strikingly, we also identify STAT3 and CDKN2A mutations in primary human PCa. STAT3 and CDKN2A deletions co-occurred with high frequency in PCa metastases. In accordance, loss of STAT3 and p14(ARF) expression in patient tumours correlates with increased risk of disease recurrence and metastatic PCa. Thus, STAT3 and ARF may be prognostic markers to stratify high from low risk PCa patients. Our findings challenge the current discussion on therapeutic benefit or risk of IL-6/STAT3 inhibition.

No MeSH data available.


Related in: MedlinePlus