SIRT1 and central nervous system cancer: In another study, miR-133b was shown to suppress glioblastoma invasion and cell migration via downregulation of metalloproteinase 14 (MMP14) in U87 and U251 glioma cells, while miR-133b was also shown to impede proliferation and invasion of glioma due to Sirt1 downregulation (144, 145).