Downregulated circFOXP1 inhibited RCC proliferation, migration, and invasion and decreased Warburg effect. (a) Cells were treated with Sh-NC, Sh-FOXP1#1, or Sh-FOXP1#2 as indicated; the expression level of circFOXP1 and mFOXP1 was measured by qRT-PCR. (b, c) Cell proliferation levels were measured using CCK-8 assay in ACHN (b) and 786-O (c) cells. (d, e) Cell migration levels were detected using transwell migration assay (d); a comparative analysis was shown (e). (f, g) Cell invasion levels were assessed by transwell invasion assay (f); a comparative analysis was calculated (g). (h–j) Expression change of glucose (h), lactate(i), and ATP (j) in ACHN and 786-O cells was detected. Experiments were repeated three times, ∗P < 0.05 and ∗∗P < 0.01.