Caspase-3 but not caspase-8 is activated by mTHPC-PDT and m-THPC-PDT / Doxorubicin in murine hepatoma MH22 cells

Abstract

We have studied activation of two apoptotic enzymes induced in murine hepatoma MH-22A cells in vitro following photodynamic treatment (PDT) mediated by meso-tetra(3-hydroxyphenyl)-chlorin (mTHPC) alone and in combination with Doxorubicin. Caspase-3, the main effector proteaze of apoptosis, was activated by mTHPC-PDT alone and in combination with Doxorubicin indicating the apoptotic death of the treated cells. However, no significant activation of initiator caspase-8 was registered, thus excluding the involvement of the caspase-8-dependent apoptosis initiation pathway in mTHPC-photosensitised and mTHPC-photosensitised / Doxorubicin-treated cell death. Keywords: PDT, mTHPC, Doxorubicin, apoptosis, caspase-3, caspase-8