miR-133b acts as a tumor suppressor and negatively regulates ATP citrate lyase via PPARγ in gastric cancer.

MicroRNAs (miRNAs/miRs) are a class of small noncoding RNAs that negatively regulate protein expression by binding to protein-coding mRNAs and suppressing translation. Accumulating evidence suggests that miRNAs are involved in the development and progression of cancer by regulating cancer metabolism. Meanwhile, the cytosolic enzyme ATP citrate lyase (ACLY) is a promising target in the prevention and treatment of cancer. In the present study we revealed by western blot analysis and reverse transcription‑quantitative PCR that miR-133b was downregulated in human gastric cancer (GC) tissues and cell lines, while ACLY was upregulated. The overexpression of miR-133b could decrease the proliferation and invasion of MKN-74 cells by inhibiting the expression and activation of ACLY. Furthermore, the nuclear distribution of peroxisome proliferator-activated receptor-γ (PPARγ) in GC tissues and cell lines was markedly decreased, and overexpression of miR-133b could increase the levels of nuclear PPARγ in MKN-74 cells. Additionally, miR-133b decreased the transcriptional activity of ACLY in a PPARγ-dependent manner, as determined by a dual-luciferase reporter assay. These results indicate that miR-133b targets ACLY and inhibits GC cell proliferation by regulating the expression of PPARγ, suggesting that miR-133b may serve as a tumor-suppressive target in GC therapy.