To explore the effect of F-box protein 6 (FBXO6) on bladder cancer cells and its possible mechanism.

Human normal bladder epithelial cell line (SV-HUC-1) and human bladder cancer cell line (T24) were cultured in vitro. T24 cells were infected with negative control for overexpression vector (oe-NC) , overexpression FBXO6 (oe-FBXO6) , overexpression ERO1L (oe-ERO1L) and oe-FBXO6 and oe-ERO1L lentivirus (MOI = 20) . RT-qPCR was used to detect the expression of FBXO6 and endoplasmic reticulum oxidoreductin-1-like protein (ERO1L) mRNA in T24 cells; the cycloheximide protein synthesis inhibition test was used to detect the stability of ERO1L protein; co-immunoprecipitation experiment was used to detect the effect of FBXO6 on the ubiquitination of ERO1L; Western blot was used to detect the expression of FBXO6 and ERO1L protein in cells; CCK-8 was used to detect cell viability; clone formation experiment was used to detect the proliferation of cells; Transwell experiment was used to detect the migration and invasion of cells. Independent sample t test was used for comparison between two groups, one-way ANOVA was used for comparison between multiple groups, and LSD-t test was used for comparison between two groups.

Compared with the SV-HUC-1 cells, the expression of FBXO6 mRNA and protein cells (1.00±0.05 vs 0.33±0.02) (1.00±0.11 vs 0.31±0.03) was significantly lower in T24 cells (both P < 0.05) , while the expression of ERO1L mRNA and protein (1.00±0.05 vs 2.70±0.12) (1.00±0.16 vs 3.27±0.09) was significantly increased (both P < 0.05) . FBXO6 could inhibit the stability of ERO1L protein and promote ERO1L ubiquitination. Compared with the blank control and the OE-NC cells, the expression of FBXO6 mRNA and protein (1.00±0.06 vs 3.74±0.18) (1.00±0.10 vs 2.25±0.06) was significantly increased in the oe-FBXO6 cells (both P < 0.05) , while the expression of ERO1L protein (0.99±0.08 vs 0.21±0.03) , cell viability, number of clones (78.00±3.00 vs 41.67±2.52) , the number of migration (150.67±5.03 vs 91.67±5.51) and invasion cells (122.00±7.00 vs 74.67±5.51) were significantly reduced (all P < 0.05) ; Compared with the oe-NC cells, the expression of ERO1L protein (1.01±0.06 vs 2.58±0.02) , cell viability, number of clones (78.00±3.00 vs 121.67±7.64) , number of migrating (150.67±5.03 vs 230.33±12.01) and invading cells (122.00±7.00 vs 203.00±11.53) were significantly increased in the ox-ERO1L cells (all P < 0.05) ; Compared with the oe-FBXO6 cells, the expression of ERO1L protein (0.54±0.02 vs 1.02±0.06) , cell viability, number of clones (41.67±2.52 vs 62.00±3.61) , number of migrating (91.67±5.51 vs 131.67±6.03) and invasive cells (74.67±5.51 vs 102.67±7.51) were significantly increased (all P < 0.05) .

FBXO6 inhibits the proliferation, migration and invasion of bladder cancer cells by mediating the degradation of ERO1L ubiquitination.