Artikel
Antiproliferative Effect of Telmisartan via PPARγ-Activation in Human Colon Cancer Cells
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Veröffentlicht: | 20. Mai 2011 |
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Introduction: Telmisartan, an AT1-Receptor-Antagonist for essential hypertension therapy, also shows partial Peroxisom Proliferator Activated Receptor γ (PPARγ) activation in preadipocytes with metabolic effects. In tumor cells, PPARγ activation leads to apoptosis and cell cycle inhibition. This study was to investigate the potential antiproliferative effect of Telmisartan by activating PPARγ in colon cancer cells.
Materials and methods: Human colon cancer cells (HT29 and SW620) were either incubated with Telmisartan (0,2-5,0µM) or the full agonist Pioglitazon (25.0 µM) as positive control for 24-72h (negative control: DMSO). Before incubation, the qualitative proof of PPARγ1 and PPARγ2 has been done by RT-PCR. The mRNA regulation of the target genes PPARγ2 and Cystatin A under the respective incubation has been measured by the means of qRT-PCR (housekeeping gene: bActin). Phenotypical changes were quantitatively determined by MTT Proliferations Assay. Apoptosis was determined by the Caspase-3/7 Assay. Statistic evaluation with PASW 18.0.
Results: PPARγ1 and PPARγ2 are expressed in HT29 and SW620. Pioglitazone inhibits proliferation after 72h in HT29 (∆ 17.48%; p<0,005) and in SW620 (∆ 22.36%; p<0,005). Telmisartan showed already at 0,2µM a proliferation inhibition of 20,06% in HT29 (p<0,005) and 18.33% in SW620 (p<0,005) (Figure 1 [Fig. 1]). Pioglitazone and Telmisartan downregulated PPARγ2mRNA in HT29 (fold change 0.2 and 0,66 respectively; n.s.) and in SW620 (fold change 0.82 and 0,68 respectively; n.s.) while upregulating CystatinA in HT29 (fold change 4.24 and 2,15 respectively; n.s.) and in SW620 (fold change 2.35 and 3,71 respectively; n.s.). Pioglitazone and Telmisartan increased the Caspase-3/7-acvtivity in HT29 and SW620 (p<0,005).
Conclusion: 1) The antihypertensive Telmisartan shows at therapeutic serum concentrations antiproliferative effects in colon cancer cells. 2) As a well-known partial PPARγ agonist, it shows an at least equivalent inhibiting effect despite comparatively smaller concentration compared to the full agonist Pioglitazone. 3) These results imply an antiproliferative effect by PPARγ1-activation.