The activating transcription factor 3 protein suppresses the oncogenic function of mutant p53 proteins.

Mutant p53 proteins (mutp53) often acquire oncogenic activities, conferring drug resistance and/or promoting cancer cell migration and invasion. Although it has been well established that such a gain of function is mainly achieved through interaction with transcriptional regulators, thereby modulating cancer-associated gene expression, how the mutp53 function is regulated remains ...
elusive. Here we report that activating transcription factor 3 (ATF3) bound common mutp53 (e.g. R175H and R273H) and, subsequently, suppressed their oncogenic activities. ATF3 repressed mutp53-induced NFKB2 expression and sensitized R175H-expressing cancer cells to cisplatin and etoposide treatments. Moreover, ATF3 appeared to suppress R175H- and R273H-mediated cancer cell migration and invasion as a consequence of preventing the transcription factor p63 from inactivation by mutp53. Accordingly, ATF3 promoted the expression of the metastasis suppressor SHARP1 in mutp53-expressing cells. An ATF3 mutant devoid of the mutp53-binding domain failed to disrupt the mutp53-p63 binding and, thus, lost the activity to suppress mutp53-mediated migration, suggesting that ATF3 binds to mutp53 to suppress its oncogenic function. In line with these results, we found that down-regulation of ATF3 expression correlated with lymph node metastasis in TP53-mutated human lung cancer. We conclude that ATF3 can suppress mutp53 oncogenic function, thereby contributing to tumor suppression in TP53-mutated cancer.
Mesh Terms:
Activating Transcription Factor 3, Carcinogenesis, Cell Line, Tumor, Cell Movement, Drug Resistance, Neoplasm, Gene Expression Regulation, Neoplastic, Humans, Lung Neoplasms, Mutant Proteins, Mutation, NF-kappa B p52 Subunit, Neoplasm Invasiveness, Neoplasm Metastasis, Transcription Factors, Tumor Suppressor Protein p53, Tumor Suppressor Proteins
J. Biol. Chem.
Date: Mar. 28, 2014
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