MiRNA array after p63 knock down in human squamous cell carcinoma

ABSTRACT: A central challenge in human cancer therapy is the identification of pathways that control tumor cell survival and chemosensitivity in the absence of functional p53. The p53-related transcription factors p63 and p73 exhibit distinct, p53-independent roles in development and cancer: p73 promotes genome stability and mediates chemosensitivity, while p63 largely lacks these p53-like functions and instead promotes proliferation and cell survival. Here, we identify a new and physiologically important mechanism of p63/p73 cross-talk which governs the balance between pro-survival and pro-apoptotic programs in both human and murine squamous cell carcinoma. Through comprehensive profiling of p63-regulated microRNAs (miRs), we identified a subset which target p73 for inhibition, including miR-193a-5p, a direct endogenous transcriptional target repressed by p63 and activated by pro-apoptotic p73 isoforms in both normal cells and tumor cells in vivo. Consequently, chemotherapy treatment causes p63/p73-dependent induction of this miR, thereby limiting chemosensitivity due to miR-mediated feedback control of p73. We demonstrate that interrupting this feedback by inhibiting miR-193a suppresses tumor cell viability and induces dramatic chemosensitivity both in vitro and in vivo. Thus, we have identified a direct, miR-dependent regulatory circuit mediating inducible chemoresistance, whose inhibition provides a new therapeutic opportunity in p53-deficient tumors.

ORGANISM(S): Mus musculus Human gammaherpesvirus 8 JC polyomavirus Rattus norvegicus Betapolyomavirus macacae Homo sapiens Murid gammaherpesvirus 4 Human immunodeficiency virus 1 Human betaherpesvirus 5 Betapolyomavirus hominis Human alphaherpesvirus 1 human gammaherpesvirus 4 Murid betaherpesvirus 1

PROVIDER: GSE25524 | GEO | 2010/11/23

SECONDARY ACCESSION(S): PRJNA133991

REPOSITORIES: GEO