Adoptive transfer of NK cells in combination with chemotherapy to improve outcomes of patients with locally advanced colon carcinoma.

Abstract

e15038 Background: The prognosis of advanced colon cancer (CC) patients remains disappointing, partly due to their greater proportion of CC-initiating cells (CICs), which is responsible for cancer drug-resistance and immune escape. Immunotherapies by harnessing the immune system to eliminate tumors have attracted broad attention. This study was to detect whether chemotherapy could enhance cytotoxicity of natural killer (NK) cells to CC cells (CCs), especially for CICs in vitro, and further evaluate the efficacy and safety of NK-cell therapy combined with chemotherapy in patients with local advanced CC. Methods: We observed that cytotoxicity of NK cells to CCs and CICs pretreated with 5-Fu or oxaliplatin. Then, an open-label pilot cohort study was conducted with local advanced CC patients who had received surgical excision. 60 patients elected to receive either NK-cell therapy combined with chemotherapy (NK-cell group, 27 patients) or pure chemotherapy (control group, 33 patients). Progression-free survival (PFS), overall survival (OS) and adverse effects were investigated. Results: Chemotherapy sensitized CCs and CICs to NK cell lysis through upregulation of their NK cell activating ligands and reducing inhibitory ligands. Poorly differentiated CCs were more susceptible to NK-cell than well-differentiated CCs, and CICs were more easily to be killed by NK cell than their differentiated CCs. In the cohort study, the 5-year PFS and OS rates in the NK-cell group were significantly higher than those in the control group (51.1% vs. 34.9%, p= 0.043; 73% vs. 51.3%, p= 0.038, respectively).Among patients with poorly differentiated carcinomas or low expression of HLA-1, median PFS in the NK-cell group vs. the control group was 23.5 vs. 11.5 months ( p= 0.047), and median OS was 30 vs. 15 months ( p= 0.043), respectively. No significant adverse reaction was found during NK-cell therapy. Conclusions: NK-cell therapy in combination with chemotherapy in locally advanced CC prevented recurrence and prolonged survival with acceptable adverse effects, especially for poorly differentiated carcinomas.