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Rosiglitazone sensitizes hepatocellular carcinoma cell lines to 5-fluorouracil antitumor activity through activation of the PPARgamma signaling pathway.

Cao LQ, Wang XL, Wang Q, Xue P, Jiao XY, Peng HP, Lu HW, Zheng Q, Chen XL, Huang XH, Fu XH, Chen JS - Acta Pharmacol. Sin. (2009)

Bottom Line: Since distribution of PTEN in HCC tissues is significantly decreased compared with the paracancerous tissue, over-expression of PTEN by rosiglitazone enhances 5-FU-inhibited cell growth of HCC.Moreover, down-regulation of COX-2 is implicated in the synergistic effect of 5-FU.The results suggest potential novel therapies for the treatment of advanced liver cancer.

View Article: PubMed Central - PubMed

Affiliation: Department of Hepatobiliary Surgery, the First Affiliated Hospital of Sun Yat-Sen University, Guangzhou 510080, China.

ABSTRACT

Aim: Resistance to 5-fluorouracil (5-FU) is a major cause of chemotherapy failure in advanced hepatocellular carcinoma (HCC). Rosiglitazone, a peroxisome proliferator-activated receptor gamma (PPARgamma) agonist, has a crucial role in growth inhibition and induction of apoptosis in several carcinoma cell lines. In this study, we examine rosiglitazone-induced sensitization of HCC cell lines (BEL-7402 and Huh-7 cells) to 5-FU.

Methods: The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay was used to evaluate cell viability. Western blotting analysis was performed to detect the protein expression (PPARgamma, PTEN, and COX-2) in BEL-7402 cells. Immunohistochemistry staining was used to examine the expression of PTEN in 100 advanced HCC tissues and paracancerous tissues. In addition, small interfering RNA was used to suppress PPARgamma, PTEN, and COX-2 expression.

Results: Rosiglitazone facilitates the anti-tumor effect of 5-FU in HCC cell lines, which is mediated by the PPARgamma signaling pathway. Activation of PPARgamma by rosiglitazone increases PTEN expression and decreases COX-2 expression. Since distribution of PTEN in HCC tissues is significantly decreased compared with the paracancerous tissue, over-expression of PTEN by rosiglitazone enhances 5-FU-inhibited cell growth of HCC. Moreover, down-regulation of COX-2 is implicated in the synergistic effect of 5-FU.

Conclusion: Rosiglitazone sensitizes hepatocellular carcinoma cell lines to 5-FU antitumor activity through the activation of PPARgamma. The results suggest potential novel therapies for the treatment of advanced liver cancer.

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(A) Cellular protein was isolated from BEL-7402 cells transfected with control or COX-2 siRNA for 48 h and was then subjected to Western blotting analysis for COX-2 protein. COX-2 siRNA inhibits COX-2 protein expression. (B) After BEL-7402 cells were transfected with control or COX-2 siRNA for 48 h the cells were exposed to rosiglitazone (30 μmol/L) in the presence or absence of 5-FU (10 μmol/L). Then, the cell viabilities were determined by MTT assay for 48 h. Data are expressed as the mean±SD of three independent experiments. bP<0.05 vs control group; Con, cells treated with 0.1% DMSO; Con siRNA, non-specific siRNA, as a negative control.
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fig5: (A) Cellular protein was isolated from BEL-7402 cells transfected with control or COX-2 siRNA for 48 h and was then subjected to Western blotting analysis for COX-2 protein. COX-2 siRNA inhibits COX-2 protein expression. (B) After BEL-7402 cells were transfected with control or COX-2 siRNA for 48 h the cells were exposed to rosiglitazone (30 μmol/L) in the presence or absence of 5-FU (10 μmol/L). Then, the cell viabilities were determined by MTT assay for 48 h. Data are expressed as the mean±SD of three independent experiments. bP<0.05 vs control group; Con, cells treated with 0.1% DMSO; Con siRNA, non-specific siRNA, as a negative control.

Mentions: COX-2 expression is associated with tumor cell proliferation and tumorigenesis15, 16. Significantly increased COX-2 protein expression was observed in HCC tissues and cell lines17, 18, which coincides with our results (Figure 3A). To evaluate the significance of down-regulation of COX-2 expression in BEL-7402 cells, we investigated cell viability by MTT assay after BEL-7402 cells were treated with rosiglitazone or COX-2 siRNA (Figure 5A). We found that the knockdown of COX-2 by specific siRNA reduced cell viability (71.49±6.62)%. Moreover, the cell growth inhibitive effect is dramatically increased in the combination of COX-2 siRNA and 5-FU group, in which the cell viability was (59.02±6.05)% (Figure 5B). Unlike the control siRNA group, this reduction in COX-2 expression by COX-2 siRNA or rosiglitazone correlates with growth inhibition of BEL-7402 cells, indicating that down-regulation of COX-2 is responsible for growth arrest of BEL-7402 cells. Similar results were obtained in Huh7 cells (data not shown).


Rosiglitazone sensitizes hepatocellular carcinoma cell lines to 5-fluorouracil antitumor activity through activation of the PPARgamma signaling pathway.

Cao LQ, Wang XL, Wang Q, Xue P, Jiao XY, Peng HP, Lu HW, Zheng Q, Chen XL, Huang XH, Fu XH, Chen JS - Acta Pharmacol. Sin. (2009)

(A) Cellular protein was isolated from BEL-7402 cells transfected with control or COX-2 siRNA for 48 h and was then subjected to Western blotting analysis for COX-2 protein. COX-2 siRNA inhibits COX-2 protein expression. (B) After BEL-7402 cells were transfected with control or COX-2 siRNA for 48 h the cells were exposed to rosiglitazone (30 μmol/L) in the presence or absence of 5-FU (10 μmol/L). Then, the cell viabilities were determined by MTT assay for 48 h. Data are expressed as the mean±SD of three independent experiments. bP<0.05 vs control group; Con, cells treated with 0.1% DMSO; Con siRNA, non-specific siRNA, as a negative control.
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4007181&req=5

fig5: (A) Cellular protein was isolated from BEL-7402 cells transfected with control or COX-2 siRNA for 48 h and was then subjected to Western blotting analysis for COX-2 protein. COX-2 siRNA inhibits COX-2 protein expression. (B) After BEL-7402 cells were transfected with control or COX-2 siRNA for 48 h the cells were exposed to rosiglitazone (30 μmol/L) in the presence or absence of 5-FU (10 μmol/L). Then, the cell viabilities were determined by MTT assay for 48 h. Data are expressed as the mean±SD of three independent experiments. bP<0.05 vs control group; Con, cells treated with 0.1% DMSO; Con siRNA, non-specific siRNA, as a negative control.
Mentions: COX-2 expression is associated with tumor cell proliferation and tumorigenesis15, 16. Significantly increased COX-2 protein expression was observed in HCC tissues and cell lines17, 18, which coincides with our results (Figure 3A). To evaluate the significance of down-regulation of COX-2 expression in BEL-7402 cells, we investigated cell viability by MTT assay after BEL-7402 cells were treated with rosiglitazone or COX-2 siRNA (Figure 5A). We found that the knockdown of COX-2 by specific siRNA reduced cell viability (71.49±6.62)%. Moreover, the cell growth inhibitive effect is dramatically increased in the combination of COX-2 siRNA and 5-FU group, in which the cell viability was (59.02±6.05)% (Figure 5B). Unlike the control siRNA group, this reduction in COX-2 expression by COX-2 siRNA or rosiglitazone correlates with growth inhibition of BEL-7402 cells, indicating that down-regulation of COX-2 is responsible for growth arrest of BEL-7402 cells. Similar results were obtained in Huh7 cells (data not shown).

Bottom Line: Since distribution of PTEN in HCC tissues is significantly decreased compared with the paracancerous tissue, over-expression of PTEN by rosiglitazone enhances 5-FU-inhibited cell growth of HCC.Moreover, down-regulation of COX-2 is implicated in the synergistic effect of 5-FU.The results suggest potential novel therapies for the treatment of advanced liver cancer.

View Article: PubMed Central - PubMed

Affiliation: Department of Hepatobiliary Surgery, the First Affiliated Hospital of Sun Yat-Sen University, Guangzhou 510080, China.

ABSTRACT

Aim: Resistance to 5-fluorouracil (5-FU) is a major cause of chemotherapy failure in advanced hepatocellular carcinoma (HCC). Rosiglitazone, a peroxisome proliferator-activated receptor gamma (PPARgamma) agonist, has a crucial role in growth inhibition and induction of apoptosis in several carcinoma cell lines. In this study, we examine rosiglitazone-induced sensitization of HCC cell lines (BEL-7402 and Huh-7 cells) to 5-FU.

Methods: The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay was used to evaluate cell viability. Western blotting analysis was performed to detect the protein expression (PPARgamma, PTEN, and COX-2) in BEL-7402 cells. Immunohistochemistry staining was used to examine the expression of PTEN in 100 advanced HCC tissues and paracancerous tissues. In addition, small interfering RNA was used to suppress PPARgamma, PTEN, and COX-2 expression.

Results: Rosiglitazone facilitates the anti-tumor effect of 5-FU in HCC cell lines, which is mediated by the PPARgamma signaling pathway. Activation of PPARgamma by rosiglitazone increases PTEN expression and decreases COX-2 expression. Since distribution of PTEN in HCC tissues is significantly decreased compared with the paracancerous tissue, over-expression of PTEN by rosiglitazone enhances 5-FU-inhibited cell growth of HCC. Moreover, down-regulation of COX-2 is implicated in the synergistic effect of 5-FU.

Conclusion: Rosiglitazone sensitizes hepatocellular carcinoma cell lines to 5-FU antitumor activity through the activation of PPARgamma. The results suggest potential novel therapies for the treatment of advanced liver cancer.

Show MeSH
Related in: MedlinePlus