TNF-α MEDIATED SECRETORY COMPONENT IS POSITIVELY REGULATED BY PI3K/AKT/MTOR IN CACO-2 CELLS

Background: Secretory component (SC) is the extracellular component of the polymeric immunoglobulin receptor (pIgR) that functions as a receptor for externally secreted polymeric immunoglobulins such as secretory IgA. SC expression is regulated by a signaling pathway involving TNF-alpha. Methods: Caco-2 cells were cotreated with TNF-alpha plus either Wortmannin, which inhibits PI3K, or Rapamycin, which inhibits mTOR. The expression of SC and pIgR mRNA were assessed by immunocytochemistry, Western blotting, and Quantitative real-time PCR. Results: Wortmannin and Rapamycin decreased the fraction of cells expressing SC, as well as the total expression of SC protein and pIgR mRNA. Conclusions: TNF-alpha regulation of SC expression is mediated through a PI3K/AKT/mTOR signaling pathway in Caco-2 cells.