Figure 5
The nuclear factor (NF)-κB signaling axis is not affected by the loss of vesicular overexpressed in cancer prosurvival protein 1 (VOPP1) expression in squamous cell carcinoma (SCC). (a) NF-κB reporter activity is shown in four cell lines undergoing siRNA-mediated knockdown of VOPP1 expression. The data are the aggregate from five independent experiments each carried out in triplicate, and are presented relative to the condition of pGL3-NFκB-luc2 reporter/control siRNA per cell line. All cell lines exhibit a significant baseline NF-κB-specific reporter activity. Only in the HeLa cell line did VOPP1 knockdown induce a significant decrease in baseline NF-κB reporter activity. Three other cell lines derived from human SCC tumors did not show evidence of changes in NF-κB reporter activity upon loss of VOPP1 expression. (b) NF-κB reporter activity is shown in four cell lines undergoing siRNA-mediated knockdown of VOPP1 expression during the activation of the NF-κB pathway by tumor necrosis factor-α (TNFα) treatment. Data are from two independent experiments conducted in triplicate for each SCC-derived cell line shown; measures of normalized NF-κB activity are presented relative to the condition of pGL3-NFκB-luc2 reporter/control siRNA and phosphate-buffered saline (PBS) treatment per cell line, as indicated. TNFα stimulation did induce increased NF-κB activity in all these systems as expected, but VOPP1 knockdown was only able to significantly abrogate this effect in HeLa cells. Thus, although the NF-κB pathway is responsive in the three SCC cell lines, its activity is unaffected by changes in VOPP1 protein expression levels. All error bars represent 95% confidence intervals, with asterisks denoting significant differences for both VOPP1 targeting siRNAs relative to control; P<0.05 from a Student's t-test without assuming equal variances.
