Figure 3
hPTTG1 overexpression activates CXCR2/p21 signaling to induce senescence. (A) The level of CXCR2 knockdown was confirmed with qRT-PCR. The results are presented as the mean ± SEM (n = 3). *P < 0.05. (B) MCF-7hPTTG1 cells stably infected with shGFP, shCXCR2-1, or shCXCR2-2 were plated for senescence assays. The percentage of positively stained cells is indicated to the right of the respective images. The results are presented as the mean ± SEM (n = 3). ***P < 0.0001. (C) Cell lysates were collected from MCF-7hPTTG1 cells and MCF-7hPTTG1 cells stably infected with shGFP, shCXCR2-1, or shCXCR2-2 for immunoblot analysis. (D) MCF-7hPTTG1 cells stably infected with shGFP, shp21-1, or shp21-2 were plated for the senescence assay. The percentage of positively stained cells is indicated to the right of the respective images. The results are presented as the mean ± SEM (n = 3). ***P < 0.0001. (E) Cell lysates were collected from MCF-7hPTTG1 cells stably infected with shGFP, shp21-1, or shp21-2 for immunoblot analysis. (F) Cell lysates were collected from MCF-7hPTTG1 cells treated with DMSO (vehicle), IgG control, CXCR2 inhibitor (SB225002), anti-CXCR2 antibody, or anti-IL-8 antibody for immunoblot analysis.