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Signal transducer and activator of transcription 3 activation is associated with bladder cancer cell growth and survival.

Chen CL, Cen L, Kohout J, Hutzen B, Chan C, Hsieh FC, Loy A, Huang V, Cheng G, Lin J - Mol. Cancer (2008)

Bottom Line: Activation of Stat3 is dependent on the phosphorylation at the tyrosine residue 705 by upstream kinases and subsequent nuclear translocation after dimerization.The survival inhibition might be mediated through apoptotic caspase 3, 8 and 9 pathways.Moreover, down-regulation of anti-apoptotic genes (Bcl-2, Bcl-xL and survivin) and a cell cycle regulating gene (cyclin D1) was associated with the cell growth inhibition and apoptosis.

View Article: PubMed Central - HTML - PubMed

Affiliation: Center for Childhood Cancer, The Research Institute at Nationwide Children's Hospital, Columbus, OH 43205, USA. Chun-Liang.Chen@nationwidechildrens.org

ABSTRACT

Background: Constitutive activation of signal transducer and activator of transcription 3 (Stat3) signaling pathway plays an important role in several human cancers. Activation of Stat3 is dependent on the phosphorylation at the tyrosine residue 705 by upstream kinases and subsequent nuclear translocation after dimerization. It remains unclear whether oncogenic Stat3 signaling pathway is involved in the oncogenesis of bladder cancer.

Results: We found that elevated Stat3 phosphorylation in 19 of 100 (19%) bladder cancer tissues as well as bladder cancer cell lines, WH, UMUC-3 and 253J. To explore whether Stat3 activation is associated with cell growth and survival of bladder cancer, we targeted the Stat3 signaling pathway in bladder cancer cells using an adenovirus-mediated dominant-negative Stat3 (Y705F) and a small molecule compound, STA-21. Both prohibited cell growth and induction of apoptosis in these bladder cancer cell lines but not in normal bladder smooth muscle cell (BdSMC). The survival inhibition might be mediated through apoptotic caspase 3, 8 and 9 pathways. Moreover, down-regulation of anti-apoptotic genes (Bcl-2, Bcl-xL and survivin) and a cell cycle regulating gene (cyclin D1) was associated with the cell growth inhibition and apoptosis.

Conclusion: These results indicated that activation of Stat3 is crucial for bladder cancer cell growth and survival. Therefore, interference of Stat3 signaling pathway emerges as a potential therapeutic approach for bladder cancer.

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Inhibition of Stat3 pathway induces apoptosis through caspase 3, 8 and 9 pathways in bladder cancer cells but not in bladder smooth muscle cells. (A) Cleaved caspase 3, 8 and 9 staining in dnStat3-transduced UMUC-3 and WH at 48 h post-infection and 31 h post-infection, respectively. Cells were transduced, fixed and then immunostained with anti-cleaved caspases 3, 8 and 9 antibodies. Cleaved caspases 3, 8 and 9 immunoreactivies were observed in cells transduced with rAd/dnStat3 but not in the cells transduced with rAd/eGFP or negative control. Cleaved caspase 3, 8, 9: anti-cleaved-caspases 3, 8, & 9 antibody immuno-fluorescent staining; Unt: untreated; DAPI: nuclear staining with DAPI; phase:phase-contrast. Magnification of images was 100×. (B) 45–75% of UMUC-3 and WH cells transduced with rAd/dnStat3 were cleaved caspase 3, 8, and 9 positive. (C) STA-21 also induced apoptosis (cleaved caspase 3 staining) in 253J, WH and UMUC-3 cells but not in BdSMC cells.
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Figure 5: Inhibition of Stat3 pathway induces apoptosis through caspase 3, 8 and 9 pathways in bladder cancer cells but not in bladder smooth muscle cells. (A) Cleaved caspase 3, 8 and 9 staining in dnStat3-transduced UMUC-3 and WH at 48 h post-infection and 31 h post-infection, respectively. Cells were transduced, fixed and then immunostained with anti-cleaved caspases 3, 8 and 9 antibodies. Cleaved caspases 3, 8 and 9 immunoreactivies were observed in cells transduced with rAd/dnStat3 but not in the cells transduced with rAd/eGFP or negative control. Cleaved caspase 3, 8, 9: anti-cleaved-caspases 3, 8, & 9 antibody immuno-fluorescent staining; Unt: untreated; DAPI: nuclear staining with DAPI; phase:phase-contrast. Magnification of images was 100×. (B) 45–75% of UMUC-3 and WH cells transduced with rAd/dnStat3 were cleaved caspase 3, 8, and 9 positive. (C) STA-21 also induced apoptosis (cleaved caspase 3 staining) in 253J, WH and UMUC-3 cells but not in BdSMC cells.

Mentions: Transduction of dnStat3 in bladder cancer cells induced activation of apoptotic caspases 3, 8, and 9 in those cells transduced with rAd/dnStat3. UMUC-3 and WH were fixed at day 2 and day 1, respectively, post-transduction of rAd/eGFP or rAd/dnStat3 and then subject to immuno-fluorescent staining using antibodies that recognize cleaved caspases 3, 8 and 9 for apoptosis evaluations. Only rare sporadic cells were found stained by anti-cleaved caspases 3, 8, and 9 antibodies in negative UMUC-3 and WH controls (untransduced or transduced with rAd/eGFP) (Figure 5A &5B). However, many dnStat3-transduced cells were positive in anti-cleaved caspases 3 (44.2 and 53%), 8 (53.5 and 74.4%), and 9 (74.2 and 42.4%) immunostaining (Figure 5B).


Signal transducer and activator of transcription 3 activation is associated with bladder cancer cell growth and survival.

Chen CL, Cen L, Kohout J, Hutzen B, Chan C, Hsieh FC, Loy A, Huang V, Cheng G, Lin J - Mol. Cancer (2008)

Inhibition of Stat3 pathway induces apoptosis through caspase 3, 8 and 9 pathways in bladder cancer cells but not in bladder smooth muscle cells. (A) Cleaved caspase 3, 8 and 9 staining in dnStat3-transduced UMUC-3 and WH at 48 h post-infection and 31 h post-infection, respectively. Cells were transduced, fixed and then immunostained with anti-cleaved caspases 3, 8 and 9 antibodies. Cleaved caspases 3, 8 and 9 immunoreactivies were observed in cells transduced with rAd/dnStat3 but not in the cells transduced with rAd/eGFP or negative control. Cleaved caspase 3, 8, 9: anti-cleaved-caspases 3, 8, & 9 antibody immuno-fluorescent staining; Unt: untreated; DAPI: nuclear staining with DAPI; phase:phase-contrast. Magnification of images was 100×. (B) 45–75% of UMUC-3 and WH cells transduced with rAd/dnStat3 were cleaved caspase 3, 8, and 9 positive. (C) STA-21 also induced apoptosis (cleaved caspase 3 staining) in 253J, WH and UMUC-3 cells but not in BdSMC cells.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2577686&req=5

Figure 5: Inhibition of Stat3 pathway induces apoptosis through caspase 3, 8 and 9 pathways in bladder cancer cells but not in bladder smooth muscle cells. (A) Cleaved caspase 3, 8 and 9 staining in dnStat3-transduced UMUC-3 and WH at 48 h post-infection and 31 h post-infection, respectively. Cells were transduced, fixed and then immunostained with anti-cleaved caspases 3, 8 and 9 antibodies. Cleaved caspases 3, 8 and 9 immunoreactivies were observed in cells transduced with rAd/dnStat3 but not in the cells transduced with rAd/eGFP or negative control. Cleaved caspase 3, 8, 9: anti-cleaved-caspases 3, 8, & 9 antibody immuno-fluorescent staining; Unt: untreated; DAPI: nuclear staining with DAPI; phase:phase-contrast. Magnification of images was 100×. (B) 45–75% of UMUC-3 and WH cells transduced with rAd/dnStat3 were cleaved caspase 3, 8, and 9 positive. (C) STA-21 also induced apoptosis (cleaved caspase 3 staining) in 253J, WH and UMUC-3 cells but not in BdSMC cells.
Mentions: Transduction of dnStat3 in bladder cancer cells induced activation of apoptotic caspases 3, 8, and 9 in those cells transduced with rAd/dnStat3. UMUC-3 and WH were fixed at day 2 and day 1, respectively, post-transduction of rAd/eGFP or rAd/dnStat3 and then subject to immuno-fluorescent staining using antibodies that recognize cleaved caspases 3, 8 and 9 for apoptosis evaluations. Only rare sporadic cells were found stained by anti-cleaved caspases 3, 8, and 9 antibodies in negative UMUC-3 and WH controls (untransduced or transduced with rAd/eGFP) (Figure 5A &5B). However, many dnStat3-transduced cells were positive in anti-cleaved caspases 3 (44.2 and 53%), 8 (53.5 and 74.4%), and 9 (74.2 and 42.4%) immunostaining (Figure 5B).

Bottom Line: Activation of Stat3 is dependent on the phosphorylation at the tyrosine residue 705 by upstream kinases and subsequent nuclear translocation after dimerization.The survival inhibition might be mediated through apoptotic caspase 3, 8 and 9 pathways.Moreover, down-regulation of anti-apoptotic genes (Bcl-2, Bcl-xL and survivin) and a cell cycle regulating gene (cyclin D1) was associated with the cell growth inhibition and apoptosis.

View Article: PubMed Central - HTML - PubMed

Affiliation: Center for Childhood Cancer, The Research Institute at Nationwide Children's Hospital, Columbus, OH 43205, USA. Chun-Liang.Chen@nationwidechildrens.org

ABSTRACT

Background: Constitutive activation of signal transducer and activator of transcription 3 (Stat3) signaling pathway plays an important role in several human cancers. Activation of Stat3 is dependent on the phosphorylation at the tyrosine residue 705 by upstream kinases and subsequent nuclear translocation after dimerization. It remains unclear whether oncogenic Stat3 signaling pathway is involved in the oncogenesis of bladder cancer.

Results: We found that elevated Stat3 phosphorylation in 19 of 100 (19%) bladder cancer tissues as well as bladder cancer cell lines, WH, UMUC-3 and 253J. To explore whether Stat3 activation is associated with cell growth and survival of bladder cancer, we targeted the Stat3 signaling pathway in bladder cancer cells using an adenovirus-mediated dominant-negative Stat3 (Y705F) and a small molecule compound, STA-21. Both prohibited cell growth and induction of apoptosis in these bladder cancer cell lines but not in normal bladder smooth muscle cell (BdSMC). The survival inhibition might be mediated through apoptotic caspase 3, 8 and 9 pathways. Moreover, down-regulation of anti-apoptotic genes (Bcl-2, Bcl-xL and survivin) and a cell cycle regulating gene (cyclin D1) was associated with the cell growth inhibition and apoptosis.

Conclusion: These results indicated that activation of Stat3 is crucial for bladder cancer cell growth and survival. Therefore, interference of Stat3 signaling pathway emerges as a potential therapeutic approach for bladder cancer.

Show MeSH
Related in: MedlinePlus