Statins inhibit Akt/PKB signaling via P2X7 receptor in pancreatic cancer cells

Biochem Pharmacol. 2009 Nov 1;78(9):1115-26. doi: 10.1016/j.bcp.2009.06.016. Epub 2009 Jun 21.

Abstract

Cholesterol-lowering statins have been shown to inhibit growth of pancreatic cancer cells in vitro and in vivo. Epidemiological studies also indicate a chemopreventive effect of statins. We have investigated the effect of statins on Akt/protein kinase B signaling. We found that atorvastatin decreased constitutive- and insulin-induced pAkt in Panc-1 and MIA PaCa-2 cells. Statins also inhibited pAkt in combination with gemcitabine- and 5-fluorouracil, and sensitized cells to gemcitabine- and 5-fluorouracil-induced apoptosis and inhibition of cell proliferation. In line with our previous data, it was found that the P2X7-purinergic receptor mediated the effects of statins in Panc-1 and MIA PaCa-2 cells. Thus, experiments employing P2X7 siRNA and inhibitors supported an involvement of P2X7. In Capan-2 cells, which expressed P2X7 in low levels, statins did not reduce pAkt levels nor did statins sensitize them to cytostatic drugs. However, statin inhibited the growth of Capan-2 cells and this correlated to inhibition of NFkappaB and Raf/MEK pathways. As shown previously, these latter effects can be explained by an inhibited protein prenylation. Our data suggest that statins primarily target a functional P2X7-Akt signaling in pancreatic cancer cells. By targeting the P2X7-Akt axis, statins can sensitize pancreatic cancer cells to chemotherapeutic drugs. Our data are also in line with a role for P2X7 in the chemopreventive effect of statins on pancreatic cancer.

MeSH terms

  • Apoptosis
  • Atorvastatin
  • Blotting, Western
  • Cell Line, Tumor
  • Cell Proliferation
  • Deoxycytidine / analogs & derivatives
  • Deoxycytidine / pharmacology
  • Fluorouracil / pharmacology
  • Gemcitabine
  • Heptanoic Acids / pharmacology
  • Humans
  • Hydroxymethylglutaryl-CoA Reductase Inhibitors / pharmacology*
  • Pancreatic Neoplasms / enzymology
  • Pancreatic Neoplasms / pathology*
  • Pancreatic Neoplasms / physiopathology
  • Proto-Oncogene Proteins c-akt / antagonists & inhibitors
  • Proto-Oncogene Proteins c-akt / metabolism*
  • Pyrroles / pharmacology
  • RNA, Small Interfering
  • Receptors, Purinergic P2 / genetics
  • Receptors, Purinergic P2 / physiology*
  • Receptors, Purinergic P2X7
  • Signal Transduction / drug effects*

Substances

  • Heptanoic Acids
  • Hydroxymethylglutaryl-CoA Reductase Inhibitors
  • P2RX7 protein, human
  • Pyrroles
  • RNA, Small Interfering
  • Receptors, Purinergic P2
  • Receptors, Purinergic P2X7
  • Deoxycytidine
  • Atorvastatin
  • Proto-Oncogene Proteins c-akt
  • Fluorouracil
  • Gemcitabine