Fig. 5.

GPX8 loss in MDA-MB-231 cells affects cancer stemness. (A) Loss of GPX8 results in CD44 cell surface expression reduction. The different indicated samples were subjected to FACS analysis of the cell-surface markers CD44. The histogram represents CD44 fluorescence intensity values. n = 3. (B) GPX8 expression levels correlate with the stem cell markers. Cells were subjected to immunoblotting with the indicated antibodies. (C) GPX8 overexpression in MDA-MB-468 cells induces CD44 expression. Cells were subjected to immunoblotting with the indicated antibodies. VC, vector control; GPX8-OE, GPX8 overexpression. (D) GPX8 expression in MDA-MD-231 cells correlates with the cells’ ability to form mammospheres. Quantification of in vitro mammosphere formation by cells from the different clones was performed. The data are reported as the number of mammospheres formed per 600 seeded cells; each value represents the mean ± SD for n = 5. The P value was determined by Student t test. (E) GPX8 loss affects tumor formation in mice. Female NOD-SCID mice were injected with 10⁶ cells generated from the different clones. After 7 wk, the proportion of animals bearing tumors was assessed and presented. The P value was determined by Fisher’s exact test. (F) GPX8 expression affects tumor formation and growth rate in mice. During the in vivo time course, the tumor volume of each group was measured weekly and presented in a graph; each value represents the mean ± SD. For GPX8-WT, n = 8; GPX8-KO-1, n = 3; GPX8-KO-1+GPX8-OE, n = 7. The P value was determined by Student t test.