We have performed laser capture microdissection with RNA microarray analysis on the invasive and non-invasive tumor cells of p53(R175H)-overexpressing OTC samples to determine candidate genes facilitating tumor invasion.
Using esophageal epithelial cells transformed by the overexpression of EGFR and p53(R175H), we find novel evidence of a functional link between p53(R175H) and the c-Met receptor tyrosine kinase to mediate tumor cell invasion.
We found that forced over-expression of p53-R175H significantly promoted cell migration and invasion, and induced activation of the epidermal growth factor receptor (EGFR)/phosphatidylinositol 3-kinase (PI3K)/AKT pathway.
Furthermore, Met activation is increased upon combinatorial overexpression of epidermal growth factor receptor (EGFR) and p53(R175H), two common genetic mutations in ESCC.
This was achieved through the retroviral-mediated transduction into normal, primary human esophageal epithelial cells of epidermal growth factor receptor (EGFR), the catalytic subunit of human telomerase (hTERT), and p53(R175H), genes that are frequently altered in human esophageal squamous cell cancer.
Since the p53 tumor suppressor pathway is inactivated in most human cancers due to gene mutations or defective wt p53 signaling, we now investigated in human wt p53 breast carcinoma MCF-7 cells, whether single treatment with the p53 transactivation pharmacological inhibitor pifithrin-alpha, transient p53 siRNA interference or stable insertion of a dominant-negative (DN) R175H p53 mutant increase: (i) EGFR/erbB1 activation, (ii) MMP-9 expression and (iii) loss of surface E-cadherin.
These findings show for the first time that elevated expression of p53-R175H mutant may exert gain-of-function activity to activate the EGFR/PI3K/AKT pathway and thus may contribute to the invasive phenotype in endometrial cancer.
These findings show for the first time that elevated expression of p53-R175H mutant may exert gain-of-function activity to activate the EGFR/PI3K/AKT pathway and thus may contribute to the invasive phenotype in endometrial cancer.
A point mutation in the TP53 tumor suppressor gene (c.524G>A; R175H) and no epidermal growth factor receptor gene amplification were revealed on molecular genetic analysis.