Cell lines (PANC-1, Capan-1, HS766T, MIA-PaCa2, and CFPAC) were purchased from ATCC (Manassas, VA). HuR knockout clones were generated as previously described (17 (link),18 (link)). PDX line SPC_145 was a gift from Dr. Talia Golan (Sheba Medical Center) (19 (link)). All cell lines were tested monthly for mycoplasma and every 6 months STR validated. Cell lines for all experiments were below passage 20.