PKG2 activates FoxO in colon cancer cells. LS174T colon cancer cells were transiently cotransfected with a Forkhead-responsive element (FHRE)–driven luciferase reporter construct and either empty vector (Vector) or expression vectors encoding FoxO1, 3, and 4 (as indicated). A: Cells were harvested, and the relative luciferase activity was determined. B: The effect of cGMP and PKG2 on FHRE-luciferase activity was determined by comparing activity in untreated cells (−) to those incubated with 8Br-cGMP (cG), doxycycline inducer (Dox), or both (+). C: The effect of PKG2 on endogenous FoxO target gene expression in LS174T cells was determined by reverse transcriptase PCR. Gels are representative of at least three experiments. Quantitative data are expressed as means ± SEM (A and B). n = 3 (A–C). ∗P < 0.05 versus vector; †P < 0.05 versus untreated cells. GADD, growth arrest and DNA damage; HPRT, hypoxanthine phosphoribosyltranferase; MnSOD, manganese superoxide dismutase; PRDX, peroxiredoxin.