Phosphatase and Tensin Homolog (PTEN) Represses Colon Cancer Progression through Inhibiting Paxillin Transcription via PI3K/AKT/NF-κB Pathway

The tumor suppressor gene phosphatase and tensin homolog (PTEN) is frequently mutated in colon cancer. However, the potential contribution of loss of PTEN to colon cancer progression remains unclear. In this study, we demonstrated that PTEN overexpression or knockdown in Lovo colon cancer cells decreased or increased paxillin expression, respectively. Moreover, paxillin reversed PTEN-mediated inhibition of Lovo cell invasion and migration. Overexpression of PTEN in an orthotropic colon cancer nude mice model inhibited tumor formation and progression. In addition, PTEN protein level was negatively correlated with that of paxillin in human colon cancer tissues. Mechanistically, we identified three NF-kappa B binding sites on paxillin promoter and confirmed that paxillin was a direct transcriptional target of NF-kappa B. Our findings reveal a novel mechanism by which PTEN inhibits the progression of colon cancer by inhibiting paxillin expression downstream of PI3K/AKT/NF kappa B pathway. Thereby, PTEN/PI3K/AKT/NF-kappa B/paxillin signaling cascade is an attractive therapeutic target for colon cancer progression.