Fig. 1

TSPAN9 is overexpressed in 5-FU-resistant gastric cancer cells. All cell lines were cultured with various concentrations (1, 2, 10, 20, 50, 100 and 200 µM) of 5-FU for 72 h. Cell proliferation activity was measured by the CCK-8 assay. Each data point represents the mean ± SD (n = 6). All 5-FU-resistant cell lines were more resistant to 5-FU than their respective parental cell lines. a The sensitivity of the parental gastric cancer cell line AGS and its 5-FU-resistant cell line (AGS/R). b Cell proliferation activity of the parental gastric cancer cell line MGC803 and its 5-FU-resistant cell line (MGC803/R). c Western blot assay of TSPAN9 in parental and drug-resistant gastric cancer cell line cells, with β-actin serving as a loading control. d qRT-PCR was employed to assess TSPAN9 expression in parental and drug-resistant gastric cancer cell lines (n = 3). GAPDH served as an internal reference. *p < 0.05, **p < 0.01; Student’s t test