Early apoptosis and cell death induced by ATX-S10Na (II)-mediated photodynamic therapy are Bax- and p53-dependent in human colon cancer cells.

Aim: To investigate the roles of Bax and p53 proteins in photosensitivity of human colon cancer cells by using lysosome-localizing photosensitizer, ATX-S10Na (II).

Methods: HCT116 human colon cancer cells and Bax-null or p53-null isogenic derivatives were irradiated with a diode laser. Early apoptosis and cell death in response to photodynamic therapy were determined by MTT assays, annexin V assays, transmission electron microscopy assays, caspase assays and western blotting.