Enhanced delivery of T cells to tumor after chemotherapy using membrane-anchored, apoptosis-targeted peptide.

Chemotherapy-induced apoptosis of tumor cells enhances the antigen presentation and sensitizes tumor cells to T cell-mediated cytotoxicity. Here we harnessed the apoptosis of tumor cells as a homing signal for the delivery of T cells to tumor. Jurkat T cells were anchored with ApoPep-1, an apoptosis-targeted peptide ligand, using the biocompatible anchor for membrane (BAM), an oleyl acid derivative. The ApoPep-1-BAM conjugate was efficiently anchored to cell membrane, while little anchoring was obtained with ApoPep-1 alone. The retention period of the ApoPep-1-BAM conjugate on cell membrane was approximately 80 and 40 min in the absence and presence of serum, respectively. ApoPep-1 was resistant to degradation in serum until 2h. The apoptosis-targeted T cells that were anchored with the ApoPep-1-BAM preferentially bound to apoptotic tumor cells over living cells. When intravenously injected into tumor-bearing mice, the number of apoptosis-targeted T cells and in vivo fluorescence signals by the homing of the cells to doxorubicin-treated tumor were higher than those of untargeted T cells. Accumulation of apoptosis-targeted T cells at other organs such as liver was not detected. These results suggest that the chemotherapy-induced apoptosis and subsequent enhancement of T cell delivery to tumor by the membrane anchoring of the apoptosis-targeted peptide could be a novel strategy for cancer immunotherapy.