Natural killer (NK) cells are an important component of the anti-tumor response. Tumor recognition by NK cells was found to be partly mediated by recently-discovered molecules termed natural cytotoxic receptors (NCRs). Adoptive cell transfer of tumor-reactive T-lymphocytes has been demonstrated to mediate the regression of large solid tumors in melanoma patients. It was shown that it was clinically feasible to modify genetically human T-lymphocytes with anti-tumor receptors, thus leading to cancer regression in melanoma patients. Nevertheless, the use of such treatments for other malignancies such as breast, colon, cervical, liver or lung cancer has barely been explored due to the lack of receptors that would mediate efficient recognition of those tumors.
Herein, we propose to combine the NK anti-tumor recognition potential with the genetic modification of T-cells, providing them with an additional mean to recognize tumors in a non-MHC restricted way. To test this, we have generated several constructs utilizing the extra-cellular domain of NCR-3 (Nkp30) or NCR-1 (Nkp46) fused to different signaling moieties. The different receptors were expressed in T-lymphocytes and their relative expression was analyzed by flow-cytometry. Following co-culture with tumors of different histologies, our results suggest that primary human T-lymphocytes expressing NCR-derived molecules are able to recognize specifically several tumor lines such as lungs, cervical carcinoma, leukemia, hepatocarcinoma and melanoma as measured by IFN-gamma, IL2 and TNF-alpha secretion tests. In addition the NCR-chimeric receptors mediated upregulation of the surface markers CD25, CD69, 4-1BB and CD107a, as well as significant antitumor activity against multiple tumor lines in cytotoxicity assays both in vitro and in ovo, using a chorioallantoic-based model of xenograft tumors.
Overall, this research has meaningful implications for the immunotherapeutic treatment of cancer using gene-modified T-cells.
