Mouse xenograft

SK-N-AS cells (4 × 10⁶) were reverse transfected with 25 nM of miR-control, miR-323a-5p or miR-342-5p in 100-mm plates (25 µL lipofectamine/dish). SK-N-BE(2) cells (4.7 × 10⁶) were reverse transfected with 25 nM of miR-control, miR-323a-5p or miR-342-5p in T175 flasks (90 µL lipofectamine/flask). Thirty-six hours post-transfection, 4 × 10⁶ cells/flank of SK-N-AS and 5 × 10⁶ cells/flank of SK-N-BE(2) were injected into the right flank of 6- to 8-week-old female NMRI-nude mice (n = 13 mice/condition of SK-N-AS and n = 15 mice/condition of SK-N-BE(2)) (Janvier Labs, Le Genest-Saint-Isle, France) in 300 µL of PBS:Matrigel (1:1). Tumor volume was measured every 2–3 days. At the end of the experiment, the primary tumors were removed and weighted. Part of the tumors were fresh frozen and the rest fixed in 10% formalin and embedded in paraffin.