15353-j-veluchamy

5 Towards UCB-NK cells treatment in colorectal cancer | 125 are EGFR + RAS mut and cetuximab monotherapy resistant. Mice were divided into 4 groups of 6 mice per group: SW480 only (group A), SW480 + cetuximab (group B), SW480 + UCB- NK (group C) and SW480 + UCB-NK + cetuximab (group D). Gaussia luciferase activity in whole blood was measured every three days to monitor the tumor burden (Supplementary figure 2). These data confirmed our in vitro observations that SW480 cells were resistant to cetuximab mediated growth inhibition (blue line). Of note, while treatment with UCB-NK cells alone significantly decreased the tumor load (green line), this effect was not increased by combining UCB-NK cells with cetuximab and thereby further confirmed both the inefficacy of cetuximab in treating RAS mutated tumors as well as the inability of cetuximab to induce ADCC of UCB-NK cells in vivo (orange line) (Figure 3). CD16 expression levels on UCB-NK cells were monitored in two mice upon adoptive transfer and increased from 6.0% before transfer to 14.0% (mouse 1) and 19.1% (mouse 2) at day 5 post UCB-NK cell infusion (data not shown). While the blood Gluc assay measurements provided evidence of a reduction in the total tumor burden after UCB-NK treatment, we wanted to explore the impact of the therapy on the localization and size of the metastases. For that purpose, BLI was performed at day Figure 3: Significant anti-tumor effects of UCB-NK cells in vivo Real time monitoring of tumor progression and treatment response was performed measuring Gluc levels from mice blood twice a week. Baseline Gluc values were obtained from all mice a day before tumor injection (day-1), and further monitoring continued until day 35. Blood Gluc levels were compared between control SW480 only (A) group and treatment groups SW480 + cetuximab (B), SW480 + UCB- NK (C) and SW480 + UCB-NK + cetuximab (D) for statistical significance. Data presented is from 6 mice per group (n=6). Scatter plots represent mean ± SEM. *P < 0.05, calculated with unpaired-t test.