Natural Killer Cell Cytotoxicity Against SKOV3 after HLA-G Downregulation by shRNA

Background: HLA-G is a nonclassical HLA class I molecule which, when elevated in tumor cells, is one of the main factors involved in tumor evasion of immune responses including NK and T cells. Objective: To evaluate the effect of HLA-G downregulation on NK cell cytotoxicity in tumor cell lines. Methods: The expression level of HLA-G was measured by real-time PCR and flowcytometry after transfection of SKOV3 by shRNA.1, which targets specific sequences in exon 4, or shRNA.2, which targets both exons 4 and 6. NK-92MI cell cytotoxicity against transfected or untransfected target cell lines was measured with the lactate dehydrogenase (LDH) release assay. The Jeg-3 cell line was used as a positive control. Results: Membrane-bound HLA-G expression levels decreased significantly in both cell lines after transfection with both shRNAs compared to their corresponding untransfected cells (p