Figure 5.
Knockdown of LLT1 at the cell surface of triple-negative breast cancer cells increased lysis of TNBCs by NK cells. A. TNBC cell line MDA-MB-436 was transfected for a period of 63 hours with scramble siRNA control or siRNA targeting LLT1 gene. Knockdown of LLT1 at the cell surface of MDA-MB-436 was confirmed by flow cytometry which displayed negligible expression of LLT1 at the cell surface (MFIR < 1.00). MFIR is median fluorescence intensity ratio. B. Transfected MDA-MB-436 cells with confirmed LLT1 knockdown at the cell surface were labeled with 51Cr and co-incubated with primary NK cells at E:T ratios of 25:1, 5:1, and 1:1 for 3.5 hours. Specific lysis of transfected MDA-MB-436 cells killed by NK cells was quantified. This assay was performed in triplicates and error bars represent standard deviations. P = 0.07 at 25:1 ratio, Student paired t-test compared to isotype control.