PHENOTYPE AND FUNCTIONALITY OF NATURAL KILLER CELLS EXPANDED FROM BREAST CANCER PATIENTS AND HEALTHY DONORS AGAINST BREAST CANCER CELL LINES

Abstract

Natural killer (NK) cells have the ability to recognize and kill cancer and virally infected cells, yet spare healthy cells; thus, they play a critical role in cancer immunosurveillance. Recent developments have allowed for ex-vivo expansion of NK cells into millions of cells from a small volume of peripheral blood, thus clearing a major hurdle in the field of adoptive NK cell immunotherapy. We explored the use of ex-vivo expanded NK cells as an autologous cell therapy for breast cancer. The main focus of our study is to assess the functionality and phenotype of ex-vivo expanded NK cells from breast cancer patients. Moreover, we tested the functionality of expanded NK cells both in vitro and in vivo, using a xenograft mouse model, against breast cancer cell lines. Finally, we investigated the potential use of cytokines to further activate expanded NK cells. Thus, we expanded NK cells from both healthy donors and cancer patients and examined their expression of different surface markers. After three weeks of culture we observed an expansion of more than one thousand fold of NK cell isolated from either breast cancer patients or healthy donors. Our results also show that the phenotype of ex-vivo expanded NK cells from cancer patients is comparable to expanded healthy donors’ NK cells. Moreover, our results confirm the ability of these NK cells to lyse both tumour cell lines in vitro. In our in vivo model, we were able to demonstrate that NK cells are capable of preventing the establishment and growth of the tumour in immunocompromised mice. Finally, we showed that cytokine activation of expanded NK cells can potentially increase their cytotoxic ability against the HER2 positive cell line; however we saw no difference in their cytotoxicity against the triple negative cell line. Thus far, we were able to demonstrate that NK cells from breast cancer patients can be expanded similarly to those from healthy donors and these NK cells also have a high cytotoxic ability against breast cancer cell lines. Furthermore, cytokine activation of expanded NK cells can be beneficial against some breast cancer subtypes.