The hsa_circ_0081534/miR-508-5p/FN1 axis in NPC. (A) Levels of FN1 were examined in NPC cells transfected with si-NC, si-circ_0081534, or si-circ_0081534 + anti-miR-508-5p through the use of Western blot. (B) Levels of miR-508-5p were examined in NPC cells transfected with si-NC, si-circRNA, or si-circRNA + anti-miR-508-5p through the use of qRT-PCR. (C) FN1 expression positively correlated with hsa_circ_0081534. (D) FN1 expression negatively correlated with miR-508-5p. (E–H) FN1 overexpression (or miR-508-5p inhibition) abolished the roles of hsa_circ_0081534 knockdown on NPC cells proliferation and invasion. 1: control; 2: si-circRNA; 3: si-circRNA+ anti-miR-508-5p; 4: si-circRNA+ FN1. *P < 0.05.