miR-99b-3p is induced by vitamin D3 and contributes to its antiproliferative effects in gastric cancer cells by targeting HoxD3.

Vitamin D3 is known to have anticancer actions by affecting tumorigenesis including the cell cycle and cell apoptosis in gastric cancer (GC) cells; the genes including microRNAs (miRNAs) regulated by vitamin D3 signaling remain discovered. miR-99b-3p, the tumor suppressor gene, is not only decreased in GC tissues, but is also induced by vitamin D3 through the vitamin D receptor (VDR) binding on the promoter domain of miR-99b. Further study indicates that miR-99b-3p inhibits cell viability and induces cell arrest in the S-phase in GC cells, the direct target gene of miR-99b-3p is verified to be HoxD3, which is also overexpressed in GC cell lines. Overall, our results show that miR-99b-3p mediates the antiproliferative of vitamin D3 in GC cells and might hold promise for prognosis and therapeutic strategies for GC treatment.