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bcl-2-specific siRNAs restore gemcitabine sensitivity in human pancreatic cancer cells.

Okamoto K, Ocker M, Neureiter D, Dietze O, Zopf S, Hahn EG, Herold C - J. Cell. Mol. Med. (2007)

Bottom Line: Combination of both methods lead to a synergistic induction of apoptosis at otherwise ineffective concentrations of Gemcitabine.Tumour growth suppression was also potentiated by the combined treatment with siBCL2 and Gemcitabine in vivo and lead to increased TUNEL positivity.In contrast, non-transformed human foreskin fibroblasts showed only minor responses to this treatment.

View Article: PubMed Central - PubMed

Affiliation: Department of Medicine 1, University Hospital Erlangen, Friedrich-Alexander-University Erlangen-Nuernberg, Ulmenweg 18, D-91054 Erlangen, Germany.

ABSTRACT
Gemcitabine has been shown to ameliorate disease related symptoms and to prolong overall survival in pancreatic cancer.Yet, resistance to Gemcitabine is commonly observed in this tumour entity and has been linked to increased expression of anti-apoptotic bcl-2. We therefore investigated if and to what extend silencing of bcl-2 by specific siRNAs (siBCL2) might enhance Gemcitabine effects in human pancreatic carcinoma cells. siBCL2 was transfected into the pancreatic cancer cell line YAP C alone and 72 hrs before co-incubation with different concentrations of Gemcitabine. Total protein and RNA were extracted for Western-blot analysis and quantitative polymerase chain reaction. Pancreatic cancer xenografts in male nude mice were treated intraperitoneally with siBCL2 alone, Gemcitabine and control siRNA or Gemcitabine and siBCL2 for 21 days. Combination of both methods lead to a synergistic induction of apoptosis at otherwise ineffective concentrations of Gemcitabine. Tumour growth suppression was also potentiated by the combined treatment with siBCL2 and Gemcitabine in vivo and lead to increased TUNEL positivity. In contrast, non-transformed human foreskin fibroblasts showed only minor responses to this treatment. Our results demonstrate that siRNA-mediated silencing of anti-apoptotic bcl-2 enhances chemotherapy sensitivity in human pancreatic cancer cells in vitro and might lead to improved therapy responses in advanced stages of this disease.

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Expression of the bcl-2 protein determined by Western blotting. (A) siRNA transfection inhibited bcl-2 protein expression of YAP C but not in HF. (B) 1 μM Gemcitabine treatment tended to down-regulate bcl-2 protein expression in YAP C in comparison to 0.01 μM Gemcitabine treated YAPC cell lines or controls. (C) The combination treatments of siBCL2 and Gemcitabine lead to a pronounced down-regulation of bcl-2 protein in YAP C but not in HF cells.
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fig03: Expression of the bcl-2 protein determined by Western blotting. (A) siRNA transfection inhibited bcl-2 protein expression of YAP C but not in HF. (B) 1 μM Gemcitabine treatment tended to down-regulate bcl-2 protein expression in YAP C in comparison to 0.01 μM Gemcitabine treated YAPC cell lines or controls. (C) The combination treatments of siBCL2 and Gemcitabine lead to a pronounced down-regulation of bcl-2 protein in YAP C but not in HF cells.

Mentions: The results obtained from Western blot also revealed that siBCL2 could inhibit bcl-2 protein expression in YAP C (Fig. 3A). The peak of inhibition was observed after 120 hrs from transfection reaching 37% of control. Pro-apoptotic bax and house keeping β-actin were stably expressed through 120 hrs. In HF there was no distinct difference between controls and treatment groups (Fig. 3A).


bcl-2-specific siRNAs restore gemcitabine sensitivity in human pancreatic cancer cells.

Okamoto K, Ocker M, Neureiter D, Dietze O, Zopf S, Hahn EG, Herold C - J. Cell. Mol. Med. (2007)

Expression of the bcl-2 protein determined by Western blotting. (A) siRNA transfection inhibited bcl-2 protein expression of YAP C but not in HF. (B) 1 μM Gemcitabine treatment tended to down-regulate bcl-2 protein expression in YAP C in comparison to 0.01 μM Gemcitabine treated YAPC cell lines or controls. (C) The combination treatments of siBCL2 and Gemcitabine lead to a pronounced down-regulation of bcl-2 protein in YAP C but not in HF cells.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3822833&req=5

fig03: Expression of the bcl-2 protein determined by Western blotting. (A) siRNA transfection inhibited bcl-2 protein expression of YAP C but not in HF. (B) 1 μM Gemcitabine treatment tended to down-regulate bcl-2 protein expression in YAP C in comparison to 0.01 μM Gemcitabine treated YAPC cell lines or controls. (C) The combination treatments of siBCL2 and Gemcitabine lead to a pronounced down-regulation of bcl-2 protein in YAP C but not in HF cells.
Mentions: The results obtained from Western blot also revealed that siBCL2 could inhibit bcl-2 protein expression in YAP C (Fig. 3A). The peak of inhibition was observed after 120 hrs from transfection reaching 37% of control. Pro-apoptotic bax and house keeping β-actin were stably expressed through 120 hrs. In HF there was no distinct difference between controls and treatment groups (Fig. 3A).

Bottom Line: Combination of both methods lead to a synergistic induction of apoptosis at otherwise ineffective concentrations of Gemcitabine.Tumour growth suppression was also potentiated by the combined treatment with siBCL2 and Gemcitabine in vivo and lead to increased TUNEL positivity.In contrast, non-transformed human foreskin fibroblasts showed only minor responses to this treatment.

View Article: PubMed Central - PubMed

Affiliation: Department of Medicine 1, University Hospital Erlangen, Friedrich-Alexander-University Erlangen-Nuernberg, Ulmenweg 18, D-91054 Erlangen, Germany.

ABSTRACT
Gemcitabine has been shown to ameliorate disease related symptoms and to prolong overall survival in pancreatic cancer.Yet, resistance to Gemcitabine is commonly observed in this tumour entity and has been linked to increased expression of anti-apoptotic bcl-2. We therefore investigated if and to what extend silencing of bcl-2 by specific siRNAs (siBCL2) might enhance Gemcitabine effects in human pancreatic carcinoma cells. siBCL2 was transfected into the pancreatic cancer cell line YAP C alone and 72 hrs before co-incubation with different concentrations of Gemcitabine. Total protein and RNA were extracted for Western-blot analysis and quantitative polymerase chain reaction. Pancreatic cancer xenografts in male nude mice were treated intraperitoneally with siBCL2 alone, Gemcitabine and control siRNA or Gemcitabine and siBCL2 for 21 days. Combination of both methods lead to a synergistic induction of apoptosis at otherwise ineffective concentrations of Gemcitabine. Tumour growth suppression was also potentiated by the combined treatment with siBCL2 and Gemcitabine in vivo and lead to increased TUNEL positivity. In contrast, non-transformed human foreskin fibroblasts showed only minor responses to this treatment. Our results demonstrate that siRNA-mediated silencing of anti-apoptotic bcl-2 enhances chemotherapy sensitivity in human pancreatic cancer cells in vitro and might lead to improved therapy responses in advanced stages of this disease.

Show MeSH
Related in: MedlinePlus