H19 and endometrial cancer: The endometrial cancer patients participating in this trial were treated with 1500–2250 mg/day, which is in the range of metformin used to treat diabetes patients.13 To test whether AMPK activation might contribute to let-7 upregulation in vitro, ARK2 cells were incubated with 5-aminoimidazole-4-carboxamide riboside (AICAR), an AMPK-activating agent,14 followed by measurement of let-7 and H19 RNA levels.