Fig 1.
Effect of PTPRE on gastric cancer cell resistance to 5-FU.
(A) Comparison of PTPRE expression between gastric cancer and normal gastric tissue samples in the TCGA database. (B) PTPRE expression levels in five gastric cancer cell lines. Relative PTPRE protein expression levels were normalized to MKN-28 cells. n = 3. (C) Changes in sensitivity to 5-FU in HS 746T cells after PTPRE knockdown. n = 3. (D) Changes in sensitivity to 5-FU in MKN-45 cells after PTPRE overexpression. n = 3. (E) IC50 values of 5-FU for each cell group. n = 3. Experimental data are shown as mean ± SD and representative of three independent experiments. ** P ＜ 0.01.
Fig 2.
Effects of PTPRE on ferroptosis in gastric cancer cells.
(A) Colony formation capacity, (B) GPX4 and SLC7A11 protein expression in each group of cells. n = 3.
Fig 3.
Effects of PTPRE on TRIB3 protein expression in gastric cancer cells.
(A) Western blot analysis revealed TRIB3 protein expression after exogenous regulation of PTPRE protein expression in MKN-45 and HS 746T cells. Relative protein expression levels were normalized to the Control group. n = 3. (B) Immunofluorescence analysis of TRIB3 expression after exogenous regulation of PTPRE protein expression in MKN-45 and HS 746T cells. Scale bar = 30 µm. Relative fluorescence intensity was normalized to the control group. n = 3. (C) Changes in TRIB3 protein expression in PTPRE-overexpressing xenograft tumours. n = 3. Scale bar = 20 µm. Experimental data are shown as mean ± SD and representative of three independent experiments. **P ＜ 0.01.
Fig 4.
Role of TRIB3 in PTPRE-mediated ferroptosis suppression in gastric cancer cells.
Changes in ROS (A), Fe²⁺ (B), GSH (C), and NADPH (D) levels in MKN-45 and HS 746T cells after exogenous regulation of PTPRE protein expression. n = 3. (E) GPX4 and SLC7A11 protein expression in each group. Relative protein expression levels were normalized to the Control group. n = 3. (F) Colony formation capacity of the cells in each group. Data were normalized to the Control group. n = 3. Experimental data are shown as mean ± SD and representative of three independent experiments. **P ＜ 0.01.
Fig 5.
Role of the Src/FAK signalling pathway in PTPRE-mediated TRIB3 upregulation.
(A) Src and FAK phosphorylation levels in MKN-45 and HS 746T cells following exogenous regulation of PTPRE protein expression. n = 3. (B) Effects of Src inhibitor 1 on PTPRE-induced upregulation of p-FAK and TRIB3 protein expression. n = 3. (C) Effects of a FAK inhibitor (Y15) on the PTPRE-induced upregulation of p-Src and TRIB3 protein expression. n = 3. (D) The effect of Src or FAK inhibition on 5-FU-induced proliferation suppression in HS 746T and MKN-45 OE-PTPRE cells. n = 3. (E) IC50 values of 5-FU for each cell group. n = 3. (F) Schematic diagram of the signaling pathway by which PTPRE inhibits ferroptosis through the Src/FAK/TRIB3 axis. Relative protein expression levels were normalized to the Control group. Experimental data are shown as mean ± SD and representative of three independent experiments. **P ＜ 0.01.
Fig 6.
PTPRE/TRIB3 inhibition of ferroptosis reduces the sensitivity of gastric cancer cells to 5-FU.
(A) Effects of TRIB3 silencing and/or inhibiting ferroptosis on 5-FU-induced proliferation inhibition in HS 746T and MKN-45 OE-PTPRE cells. n = 3. (B) IC50 values of 5-FU for each cell group. n = 3. (C) Effects of silencing TRIB3 and/or inhibiting ferroptosis on 5-FU-induced apoptosis in HS 746T and MKN-45 OE-PTPRE cells. n = 3. (D) Photograph of MKN-45 and MKN-45 OE-PTPRE xenograft tumours. n = 4. (E) Tumour volume in each group. n = 4. (F) Tumour weight in each group. n = 4. Experimental data are shown as mean ± SD and representative of three independent experiments. **P ＜ 0.01.