Sensitizing tumor cells to immune-mediated cytotoxicity.

The molecular basis underlying tumor destruction in vivo by specific antitumor CD8+ T cells remains unclear. We propose that the local production of certain tumor necrosis factor (TNF)-family members (death ligands) may be more important for tumor destruction in vivo than previously thought. Also, the apoptotic response of some tumor cells to the TNF-family member TRAIL can be augmented by the proteasome inhibitor bortezomib (Velcade). Thus, bortezomib may sensitize tumor cells to T cell-mediated cytotoxicity and could potentially improve the beneficial effects of immunotherapy.