Fig. 1.

Cancer cell lines harboring p53 mutant proteins show elevated expression of both HER2 mRNA and protein. A panel of human cancer cell lines harboring p53R273C, p53R175H and p53R248Q mutant p53 proteins (C33A, SKBR-3 and OVCAR-3, respectively), as well as cells containing wild-type p53 (wtp53) protein (MCF-7 and HeLa), and null p53 expression (Saos-2) were analyzed to determine HER2 mRNA and protein expression. HeLa cell line expresses wtp53 but its expression is decreased by Human Papillomavirus 18 (wtp53^•). a HER2 relative mRNA expression was measured by quantitative RT-PCR (RT-qPCR); final data were calculated by the comparative threshold cycle (CT) method (2^-ΔΔCT), employing the β2-microglobulin (β2M) transcript as normalization control. The results are shown as the mean ± the standard error of the mean (SEM) of three independent assays. Statistical analysis was performed by comparing each cell line against Saos-2 cell line with t-student test, *p < 0.05; ns = non-significant statistical analysis. b HER2 protein levels were measured by Western Blot assay. Equal amounts of total cell lysates were blotted and proteins were identified as described in the Materials and Methods, with specific antibodies against HER2 and p53. Blots were stripped and re-probed for anti-β-actin as loading control. Image is representative of three independent experiments