Fig. 2: Pharmacological and genetic inhibition of ERK5 impairs sphere formation in colon cancer cells. | Cell Death Discovery

Fig. 2: Pharmacological and genetic inhibition of ERK5 impairs sphere formation in colon cancer cells.

From: MEK5/ERK5 activation regulates colon cancer stem-like cell properties

Fig. 2

ae HCT116, HT29, SW480, and SW620 cells were cultured for two generations under sphere-forming conditions in the presence or absence of 4 µM XMD8-92. a The inhibitory effect of XMD8-92 on ERK5 activation was confirmed by western blot analysis. b Representative images of first-generation tumorspheres at ×100 magnification. Scale bar, 100 μm. c The rate of tumorsphere formation was measured in primary (with XMD8-92 treatment) and secondary cultures (without additional treatment). d Tumorsphere size was determined according to the number of cells per sphere in first-generation cultures. e Single-cell assays were performed using HCT116 and SW620 cells to validate the impact of XMD8-92 on clonal sphere formation. fi HCT116 cells were transiently transfected with a specific small interfering RNA (siRNA) against ERK5, or control siRNA, and then cultured in non-adherent conditions. f ERK5 silencing was monitored by immunoblot analysis during the period of tumorsphere growth. g Representative images of 7-day tumorspheres at ×100 magnification. Scale bar, 100 μm. h Tumorspheres were scored according to number (left panel) and i size (cells per sphere; right panel). Results are expressed as mean ± standard error of mean from at least four independent experiments. *p < 0.05, **p < 0.01, and ***p < 0.001 from vehicle control treatment (ce) or control siRNA spheres (h, i)

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