Increase of Interferon gamma (IFN-γ ) and Tumor necrosis factor alpha ( TNF-α ) in CD107a + NK-92 cells co-cultured with Cervical cancer cell (CCC) lines pre-treated with Heme oxygenase 1 (HO-1) inhibitor. CCC were pre-treated with HO-1 inhibitor (SnPP) for 48 h; after that, NK-92 cells were co-cultured with HeLa, SiHa, and C-33A CCC for 4 h. Then, the expression of IFN-γ and TNF-α was analyzed in CD107a + NK-92 cells by Flow cytometry (FC). Expression of IFN-γ and TNF-α in CD107a + NK-92 cells without co-culture and in NK-92 cells stimulated with PMA/Ionomycin (positive control), gray profiles represent isotype controls (a). A representative experimental of IFN-γ and TNF-α production in CD107a + Natural killer (NK)-92/CCC co-culture (b). The percentage of IFN-γ and TNF-α production in CD107a + NK-92/CCC co-culture (c). Bars represent the mean ± Standard deviation (SD) of three independent experiments carried out in triplicate. *P <0.05 1:5 + SnPP or 1:20 + SnPP vs. 1:5 or 1:20 in HeLa, SiHa, and C-33A. Mann-Whitney U test.