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Role of 14-3-3σ in poor prognosis and in radiation and drug resistance of human pancreatic cancers.

Li Z, Dong Z, Myer D, Yip-Schneider M, Liu J, Cui P, Schmidt CM, Zhang JT - BMC Cancer (2010)

Bottom Line: In the present study, we tested this hypothesis.A stable cell line expressing 14-3-3σ was established and the effect of 14-3-3σ over-expression on cellular response to radiation and anticancer drugs were tested using SRB assay and clonogenic assays.We found that 14-3-3σ protein level was increased significantly in about 71% (17 of 24) of human pancreatic cancer tissues and that the 14-3-3σ protein level in cancers correlated with lymph node metastasis and poor prognosis.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, IN 46202, USA. jianzhan@iupui.edu.

ABSTRACT

Background: Pancreatic cancer is the fourth leading cause of death in the US. Unlike other solid tumors such as testicular cancer which are now curable, more than 90% of pancreatic cancer patients die due to lack of response to therapy. Recently, the level of 14-3-3σ mRNA was found to be increased in pancreatic cancers and this increased expression may contribute to the failure in treatment of pancreatic cancers. In the present study, we tested this hypothesis.

Methods: Western blot analysis was used to determine 14-3-3σ protein level in fresh frozen tissues and was correlated to clinical outcome. A stable cell line expressing 14-3-3σ was established and the effect of 14-3-3σ over-expression on cellular response to radiation and anticancer drugs were tested using SRB assay and clonogenic assays. Cell cycle distribution and apoptosis analyses were performed using propidium iodide staining and PARP cleavage assays.

Results: We found that 14-3-3σ protein level was increased significantly in about 71% (17 of 24) of human pancreatic cancer tissues and that the 14-3-3σ protein level in cancers correlated with lymph node metastasis and poor prognosis. Furthermore, we demonstrated that over-expression of 14-3-3σ in a pancreatic cancer cell line caused resistance to γ-irradiation as well as anticancer drugs by causing resistance to treatment-induced apoptosis and G2/M arrest.

Conclusion: The increased level of 14-3-3σ protein likely contributes to the poor clinical outcome of human pancreatic cancers by causing resistance to radiation and anticancer drugs. Thus, 14-3-3σ may serve as a prognosis marker predicting survival of pancreatic cancer patients and guide the clinical treatment of these patients.

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Related in: MedlinePlus

14-3-3σ expression in paired normal and cancer pancreas. A, Western blot analysis. Lysates from fresh frozen matching human normal (N) and pancreatic ductal adenocarcinoma (C) tissues were separated by SDS-PAGE followed by Western blot analysis of 14-3-3σ and GAPDH control. The relative level (R.L.) of 14-3-3σ in each sample was measured and normalized to that of GAPDH. The level of 14-3-3σ in each normal tissue was set to 1. B, summary of Western blot analysis. The relative levels of 14-3-3σ in normal and cancer tissues were graphed with the median level in each group marked by (-). Statistical analysis was done using Student T-test.
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Figure 1: 14-3-3σ expression in paired normal and cancer pancreas. A, Western blot analysis. Lysates from fresh frozen matching human normal (N) and pancreatic ductal adenocarcinoma (C) tissues were separated by SDS-PAGE followed by Western blot analysis of 14-3-3σ and GAPDH control. The relative level (R.L.) of 14-3-3σ in each sample was measured and normalized to that of GAPDH. The level of 14-3-3σ in each normal tissue was set to 1. B, summary of Western blot analysis. The relative levels of 14-3-3σ in normal and cancer tissues were graphed with the median level in each group marked by (-). Statistical analysis was done using Student T-test.

Mentions: To determine the status of 14-3-3σ expression at its protein level in human pancreatic cancers relative to the corresponding normal tissues, we collected 24 pairs of fresh-frozen normal and cancer pancreatic tissues and determined the protein level of 14-3-3σ in these samples using Western blot. The relative 14-3-3σ protein level was then determined. As shown in Figure 1A, 17 of the 24 cases (70.8%) show increased 14-3-3σ expression in cancers compared to their matching normal pancreatic tissues. This increase is statistically significant (Figure 1B). In many cases, the increase is dramatic with one case (#114) demonstrating ~46-fold increase in cancer compared to normal tissues. Of the 24 cases, 4 (16.7%) (#149, #71, #7, #309-03) have decreased 14-3-3σ expression in cancer tissues whereas the remaining 3 (12.5%) (#56, #43, and #303-20) show no observable differences between normal and cancer tissues. These data clearly indicate that the 14-3-3σ protein level is significantly increased in the majority of pancreatic cancer tissues compared to their corresponding normal tissues.


Role of 14-3-3σ in poor prognosis and in radiation and drug resistance of human pancreatic cancers.

Li Z, Dong Z, Myer D, Yip-Schneider M, Liu J, Cui P, Schmidt CM, Zhang JT - BMC Cancer (2010)

14-3-3σ expression in paired normal and cancer pancreas. A, Western blot analysis. Lysates from fresh frozen matching human normal (N) and pancreatic ductal adenocarcinoma (C) tissues were separated by SDS-PAGE followed by Western blot analysis of 14-3-3σ and GAPDH control. The relative level (R.L.) of 14-3-3σ in each sample was measured and normalized to that of GAPDH. The level of 14-3-3σ in each normal tissue was set to 1. B, summary of Western blot analysis. The relative levels of 14-3-3σ in normal and cancer tissues were graphed with the median level in each group marked by (-). Statistical analysis was done using Student T-test.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2991307&req=5

Figure 1: 14-3-3σ expression in paired normal and cancer pancreas. A, Western blot analysis. Lysates from fresh frozen matching human normal (N) and pancreatic ductal adenocarcinoma (C) tissues were separated by SDS-PAGE followed by Western blot analysis of 14-3-3σ and GAPDH control. The relative level (R.L.) of 14-3-3σ in each sample was measured and normalized to that of GAPDH. The level of 14-3-3σ in each normal tissue was set to 1. B, summary of Western blot analysis. The relative levels of 14-3-3σ in normal and cancer tissues were graphed with the median level in each group marked by (-). Statistical analysis was done using Student T-test.
Mentions: To determine the status of 14-3-3σ expression at its protein level in human pancreatic cancers relative to the corresponding normal tissues, we collected 24 pairs of fresh-frozen normal and cancer pancreatic tissues and determined the protein level of 14-3-3σ in these samples using Western blot. The relative 14-3-3σ protein level was then determined. As shown in Figure 1A, 17 of the 24 cases (70.8%) show increased 14-3-3σ expression in cancers compared to their matching normal pancreatic tissues. This increase is statistically significant (Figure 1B). In many cases, the increase is dramatic with one case (#114) demonstrating ~46-fold increase in cancer compared to normal tissues. Of the 24 cases, 4 (16.7%) (#149, #71, #7, #309-03) have decreased 14-3-3σ expression in cancer tissues whereas the remaining 3 (12.5%) (#56, #43, and #303-20) show no observable differences between normal and cancer tissues. These data clearly indicate that the 14-3-3σ protein level is significantly increased in the majority of pancreatic cancer tissues compared to their corresponding normal tissues.

Bottom Line: In the present study, we tested this hypothesis.A stable cell line expressing 14-3-3σ was established and the effect of 14-3-3σ over-expression on cellular response to radiation and anticancer drugs were tested using SRB assay and clonogenic assays.We found that 14-3-3σ protein level was increased significantly in about 71% (17 of 24) of human pancreatic cancer tissues and that the 14-3-3σ protein level in cancers correlated with lymph node metastasis and poor prognosis.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, IN 46202, USA. jianzhan@iupui.edu.

ABSTRACT

Background: Pancreatic cancer is the fourth leading cause of death in the US. Unlike other solid tumors such as testicular cancer which are now curable, more than 90% of pancreatic cancer patients die due to lack of response to therapy. Recently, the level of 14-3-3σ mRNA was found to be increased in pancreatic cancers and this increased expression may contribute to the failure in treatment of pancreatic cancers. In the present study, we tested this hypothesis.

Methods: Western blot analysis was used to determine 14-3-3σ protein level in fresh frozen tissues and was correlated to clinical outcome. A stable cell line expressing 14-3-3σ was established and the effect of 14-3-3σ over-expression on cellular response to radiation and anticancer drugs were tested using SRB assay and clonogenic assays. Cell cycle distribution and apoptosis analyses were performed using propidium iodide staining and PARP cleavage assays.

Results: We found that 14-3-3σ protein level was increased significantly in about 71% (17 of 24) of human pancreatic cancer tissues and that the 14-3-3σ protein level in cancers correlated with lymph node metastasis and poor prognosis. Furthermore, we demonstrated that over-expression of 14-3-3σ in a pancreatic cancer cell line caused resistance to γ-irradiation as well as anticancer drugs by causing resistance to treatment-induced apoptosis and G2/M arrest.

Conclusion: The increased level of 14-3-3σ protein likely contributes to the poor clinical outcome of human pancreatic cancers by causing resistance to radiation and anticancer drugs. Thus, 14-3-3σ may serve as a prognosis marker predicting survival of pancreatic cancer patients and guide the clinical treatment of these patients.

Show MeSH
Related in: MedlinePlus