Pancreatic Tumor Suppression by Benzyl Isothiocyanate Is Associated with Inhibition of PI3K/AKT/FOXO Pathway

Abstract

Purpose: Our previous studies have shown that benzyl isothiocyanate (BITC) suppress pancreatic cancer growth by inducing apoptosis but the molecular mechanism was unclear. In this study we hypothesized the involvement of PI3K/AKT/FOXO pathway in BITC-induced apoptosis.Experimental Design: Mice were implanted BxPC-3 tumor xenografts and orally gavaged with 12 mmol BITC. Plasma and tumor BITC concentration was estimated by liquid chromatography/tandem mass spectrometry. BxPC-3 and PanC-1 cells were used to elucidate PI3K/AKT/FOXO pathway. Electrophoretic mobility shift assay (EMSA), DNA binding activity, immunofluorescence, and gene transfection were used to delineate the mechanism.Results: BITC-treated mice showed 43% less tumor growth as compared with control mice and correlated well with the therapeutic concentrations of 6.5 mmol/L BITC achieved in plasma and 7.5 mmol/g BITC in tumor tissue. Western blot analyses and immunohistochemistry revealed that tumors from BITC-treated mice showed reduced phosphorylation of PI3K, AKT, PDK1, mTOR, FOXO1, and FOXO3a and increased apoptosis. Complementing our in vivo results, we made similar observations in a dose-and time-dependent manner in BITC-treated BxPC-3 and Panc-1 cells. Binding of FOXO1 with 14-3-3 proteins was also reduced drastically by BITC treatment indicating nuclear retention of FOXO1 and this observation was further confirmed with EMSA, immunofluorescence, DNA binding, and upregulation of FOXOresponsive proteins Bim, p27, and p21 in BxPC-3 cells. Overexpression of AKT by transient transfection significantly blocked the modulation of FOXO proteins and protected the cells from BITC-mediated apoptosis and growth suppression.Conclusions: Our results provide convincing evidence on the involvement of PI3K/AKT/FOXO pathway in BITC-mediated pancreatic tumor growth suppression.

Expression pattern and transcriptional regulatory mechanism of noxa gene in grass carp (Ctenopharyngodon idella)

“…FOXO1 protein is implicated in diverse cellular activities including DNA repair, oxidative stress resistance, and apoptosis [31,32]. Moreover, enhanced FOXO1 transcription activity is required to promote apoptosis and cell cycle [33]. CCAAT/enhancer binding protein beta (C/EBPb) is a transcription factor belonging to C/EBPs, which all have a highly conserved, basic leucine zipper domain at the C-terminus involved in dimerization and DNA binding [34].…”

Microarray expression profile analysis of long non-coding RNAs in pancreatic ductal adenocarcinoma

“…The gene category Wnt signaling pathway, has been reported to be involved in metastasis of pancreatic carcinogenesis (25), and the gene category MAPK signaling pathway has been shown to participate in the progression of pancreatic cancer though multiple mechanisms (26)(27)(28)70). The gene categories FoxO signaling pathway have been reported to suppress or activate pancreatic cancer progression by different drugs or compound (29,30). The gene categories 'Ubiquitin mediated proteolysis' participates in pancreatic cancer cell growth in vitro and in vivo (31).…”

Purified vitexin compound 1 induces apoptosis through activation of FOXO3a in hepatocellular carcinoma

“…Previous studies indicated that the effects of anticancer agents may be regulated through activation of FOXO transcription factors (41)(42)(43). In addition to their effects on cell cycle, apoptosis, differentiation and reactive oxygen species, FOXO proteins have also been implicated in the negative regulation of angiogenesis.…”