Reference - Detail
|Author||Baba A, Shimizu M, Ohno T, Shirakami Y, Kubota M, Kochi T, Terakura D, Tsurumi H, Moriwaki H.|
|Title||Synergistic growth inhibition by acyclic retinoid and phosphatidylinositol 3-kinase inhibitor in human hepatoma cells.|
BACKGROUND:A malfunction of RXRα due to phosphorylation is associated with liver carcinogenesis, and acyclic retinoid (ACR), which targets RXRα, can prevent the development of hepatocellular carcinoma (HCC). Activation of PI3K/Akt signaling plays a critical role in the proliferation and survival of HCC cells. The present study examined the possible combined effects of ACR and LY294002, a PI3K inhibitor, on the growth of human HCC cells.
METHODS:This study examined the effects of the combination of ACR plus LY294002 on the growth of HLF human HCC cells.
RESULTS:ACR and LY294002 preferentially inhibited the growth of HLF cells in comparison with Hc normal hepatocytes. The combination of 1 μM ACR and 5 μM LY294002, in which the concentrations used are less than the IC₅₀ values of these agents, synergistically inhibited the growth of HLF, Hep3B, and Huh7 human HCC cells. These agents when administered in combination acted cooperatively to induce apoptosis in HLF cells. The phosphorylation of RXRα, Akt, and ERK proteins in HLF cells were markedly inhibited by treatment with ACR plus LY294002. Moreover, this combination also increased RXRE promoter activity and the cellular levels of RARβ and p21(CIP1), while decreasing the levels of cyclin D1.
CONCLUSION:ACR and LY294002 cooperatively increase the expression of RARβ, while inhibiting the phosphorylation of RXRα, and that these effects are associated with the induction of apoptosis and the inhibition of cell growth in human HCC cells. This combination might therefore be effective for the chemoprevention and chemotherapy of HCC.
|MeSH||Apoptosis / drug effects Carcinoma, Hepatocellular / metabolism* Cell Line, Tumor Cell Proliferation / drug effects Chromones / pharmacology* Cyclin D1 / metabolism Cyclin-Dependent Kinase Inhibitor p21 / metabolism Drug Synergism Extracellular Signal-Regulated MAP Kinases / metabolism Hepatocytes / drug effects Hepatocytes / metabolism Humans Liver Neoplasms / metabolism* Morpholines / pharmacology* Phosphatidylinositol 3-Kinases / antagonists & inhibitors* Phosphatidylinositol 3-Kinases / metabolism Phosphorylation / drug effects Proto-Oncogene Proteins c-akt / metabolism Retinoid X Receptor alpha / metabolism Retinoid X Receptor beta / metabolism Tretinoin / analogs & derivatives* Tretinoin / pharmacology|
|Human and Animal Cells|