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Upregulation of CYP2S1 by oxaliplatin is associated with p53 status in colorectal cancer cell lines

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ABSTRACT

Oxaliplatin displays a wide spectrum of antitumor activities and is widely used in the treatment of metastatic colorectal cancer (CRC). However, tumor responses to this agent are variable, and the underlying mechanisms are poorly understood. In the present study, oxaliplatin was found to strongly inhibit the growth of HCT116 cells harboring wild-type p53 but to only weakly inhibit SW480 cells, HT29 cells or p53−/− HCT116 cells, which all lack p53 expression. Administration of oxaliplatin significantly induced p53 accumulation and enhanced expression of CYP2S1 in HCT116 cells with wild-type p53. CYP2S1 knockdown conferred a cell survival advantage after oxaliplatin treatment to cells harboring wild-type p53 in vitro and in vivo. Interestingly, enzyme immunoassays, TOPFlash/FOPFlash reporter activity assays and western blotting analysis demonstrated oxaliplatin-mediated downregulation of PGE2 and Wnt/β-catenin signaling in a manner dependent on p53. Moreover, oxaliplatin treatment of mice with subcutaneous tumor xenografts drastically reduced the volume of wild-type p53 HCT116 tumors but had no effect on isogenic p53−/− HCT116 tumors. These results suggest that oxaliplatin exerts its inhibitory effects in human CRC cells via upregulation of CYP2S1 expression in a p53-dependent manner.

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Involvement of p53 in CYP2S1 induction by oxaliplatin in colorectal cancer cells.(A) p53+/+HCT116 cells, SW480 cells, HT29 cells and p53−/− HCT116 cells were treated with oxaliplatin (20 μM) for 24 h; total protein was extracted, and the protein levels of total p53 and CYP2S1 were analyzed by western blotting. The results shown are representative of three experiments. (B) Ectopic expression of p53 markedly increased SW480 cells’ CYP2S1 transcriptional activity after Oxaliplatin treatment for 24 h. Data are represented as mean ± s.d., **p < 0.01. (C, D) Effect of oxaliplatin treated on CYP2S1 mRNA expression. Isogenic p53+/+ HCT116 and p53−/− HCT116 cells were treated with oxaliplatin for 24 h; total RNA was extracted, and CYP2S1 mRNA expression was analyzed by Taqman-based real-time RT-PCR analysis. GAPDH was used as an endogenous control. (E) Cells were treated as described in panels C and D. CYP2S1 protein expression was analyzed by western blotting. GAPDH was used as an endogenous control. Representative results from three experiments are shown.
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f2: Involvement of p53 in CYP2S1 induction by oxaliplatin in colorectal cancer cells.(A) p53+/+HCT116 cells, SW480 cells, HT29 cells and p53−/− HCT116 cells were treated with oxaliplatin (20 μM) for 24 h; total protein was extracted, and the protein levels of total p53 and CYP2S1 were analyzed by western blotting. The results shown are representative of three experiments. (B) Ectopic expression of p53 markedly increased SW480 cells’ CYP2S1 transcriptional activity after Oxaliplatin treatment for 24 h. Data are represented as mean ± s.d., **p < 0.01. (C, D) Effect of oxaliplatin treated on CYP2S1 mRNA expression. Isogenic p53+/+ HCT116 and p53−/− HCT116 cells were treated with oxaliplatin for 24 h; total RNA was extracted, and CYP2S1 mRNA expression was analyzed by Taqman-based real-time RT-PCR analysis. GAPDH was used as an endogenous control. (E) Cells were treated as described in panels C and D. CYP2S1 protein expression was analyzed by western blotting. GAPDH was used as an endogenous control. Representative results from three experiments are shown.

Mentions: The anticancer chemotherapeutic compound oxaliplatin, which activates p53, is metabolized by drug-metabolizing enzymes. To determine whether oxaliplatin treatment induces CYP2S1 expression, we treated colorectal cancer cell lines with an oxaliplatin dose that reflects the peak plasma concentration reported in clinical 24 h-measurements36. Western blots were then performed to analyze p53 and CYP2S1 protein expression. As expected, oxaliplatin treatment of p53+/+ HCT116 cells resulted in a remarkable elevation in p53 protein levels, and these cells showed an increase in CYP2S1 protein expression. Conversely, no effect was observed in p53-deficient cells (Fig. 2A). Thus, oxaliplatin induces CYP2S1 expression in CRC cells in a p53-dependent manner.


Upregulation of CYP2S1 by oxaliplatin is associated with p53 status in colorectal cancer cell lines
Involvement of p53 in CYP2S1 induction by oxaliplatin in colorectal cancer cells.(A) p53+/+HCT116 cells, SW480 cells, HT29 cells and p53−/− HCT116 cells were treated with oxaliplatin (20 μM) for 24 h; total protein was extracted, and the protein levels of total p53 and CYP2S1 were analyzed by western blotting. The results shown are representative of three experiments. (B) Ectopic expression of p53 markedly increased SW480 cells’ CYP2S1 transcriptional activity after Oxaliplatin treatment for 24 h. Data are represented as mean ± s.d., **p < 0.01. (C, D) Effect of oxaliplatin treated on CYP2S1 mRNA expression. Isogenic p53+/+ HCT116 and p53−/− HCT116 cells were treated with oxaliplatin for 24 h; total RNA was extracted, and CYP2S1 mRNA expression was analyzed by Taqman-based real-time RT-PCR analysis. GAPDH was used as an endogenous control. (E) Cells were treated as described in panels C and D. CYP2S1 protein expression was analyzed by western blotting. GAPDH was used as an endogenous control. Representative results from three experiments are shown.
© Copyright Policy - open-access
Related In: Results  -  Collection

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f2: Involvement of p53 in CYP2S1 induction by oxaliplatin in colorectal cancer cells.(A) p53+/+HCT116 cells, SW480 cells, HT29 cells and p53−/− HCT116 cells were treated with oxaliplatin (20 μM) for 24 h; total protein was extracted, and the protein levels of total p53 and CYP2S1 were analyzed by western blotting. The results shown are representative of three experiments. (B) Ectopic expression of p53 markedly increased SW480 cells’ CYP2S1 transcriptional activity after Oxaliplatin treatment for 24 h. Data are represented as mean ± s.d., **p < 0.01. (C, D) Effect of oxaliplatin treated on CYP2S1 mRNA expression. Isogenic p53+/+ HCT116 and p53−/− HCT116 cells were treated with oxaliplatin for 24 h; total RNA was extracted, and CYP2S1 mRNA expression was analyzed by Taqman-based real-time RT-PCR analysis. GAPDH was used as an endogenous control. (E) Cells were treated as described in panels C and D. CYP2S1 protein expression was analyzed by western blotting. GAPDH was used as an endogenous control. Representative results from three experiments are shown.
Mentions: The anticancer chemotherapeutic compound oxaliplatin, which activates p53, is metabolized by drug-metabolizing enzymes. To determine whether oxaliplatin treatment induces CYP2S1 expression, we treated colorectal cancer cell lines with an oxaliplatin dose that reflects the peak plasma concentration reported in clinical 24 h-measurements36. Western blots were then performed to analyze p53 and CYP2S1 protein expression. As expected, oxaliplatin treatment of p53+/+ HCT116 cells resulted in a remarkable elevation in p53 protein levels, and these cells showed an increase in CYP2S1 protein expression. Conversely, no effect was observed in p53-deficient cells (Fig. 2A). Thus, oxaliplatin induces CYP2S1 expression in CRC cells in a p53-dependent manner.

View Article: PubMed Central - PubMed

ABSTRACT

Oxaliplatin displays a wide spectrum of antitumor activities and is widely used in the treatment of metastatic colorectal cancer (CRC). However, tumor responses to this agent are variable, and the underlying mechanisms are poorly understood. In the present study, oxaliplatin was found to strongly inhibit the growth of HCT116 cells harboring wild-type p53 but to only weakly inhibit SW480 cells, HT29 cells or p53&minus;/&minus; HCT116 cells, which all lack p53 expression. Administration of oxaliplatin significantly induced p53 accumulation and enhanced expression of CYP2S1 in HCT116 cells with wild-type p53. CYP2S1 knockdown conferred a cell survival advantage after oxaliplatin treatment to cells harboring wild-type p53 in vitro and in vivo. Interestingly, enzyme immunoassays, TOPFlash/FOPFlash reporter activity assays and western blotting analysis demonstrated oxaliplatin-mediated downregulation of PGE2 and Wnt/&beta;-catenin signaling in a manner dependent on p53. Moreover, oxaliplatin treatment of mice with subcutaneous tumor xenografts drastically reduced the volume of wild-type p53 HCT116 tumors but had no effect on isogenic p53&minus;/&minus; HCT116 tumors. These results suggest that oxaliplatin exerts its inhibitory effects in human CRC cells via upregulation of CYP2S1 expression in a p53-dependent manner.

No MeSH data available.


Related in: MedlinePlus