Increase of IFN-γ and TNF-α production in CD107a + NK-92 cells co-cultured with cervical cancer cell lines pre-treated with the HO-1 inhibitor.

Paulina Gómez-Lomelí,José Manuel Lerma-Díaz,Jorge Ramiro Domínguez-Rodríguez,Alejandro Bravo-Cuellar,Karina Sánchez-Reyes,Adriana Aguilar-Lemarroy,Pablo Cesar Ortiz-Lazareno,Georgina Hernández-Flores,Luis Felipe Jave-Suárez

doi:10.1186/s12935-014-0100-1

Paulina Gómez-Lomelí, José Manuel Lerma-Díaz + Show 7 more

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https://doi.org/10.1186/s12935-014-0100-1

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Abstract

BackgroundNatural killer (NK) cells eliminate virus-infected and tumor cells through the release of perforins and granzymes; they also produce Interferon gamma (IFN-γ) and Tumor necrosis factor alpha (TNF-α), which induce apoptosis in target cells. Many tumors express Heme oxygenase 1 (HO-1), and this expression has been associated with avoiding immunosuppression and apoptosis. In this work, HO-1+ Cervical cancer cell (CCC) lines were pre-treated with HO-1 inhibitor and we assessed whether this inhibition enhanced the sensitivity of CCC to NK cell activity.MethodsWe assessed the expression of HO-1 in HeLa, SiHa, and C-33A CCC by Flow cytometry (FC). CCC were pre-treated with SnPP or ZnPP HO-1 inhibitors. After that, NK-92 cells were co-cultured with HeLa, SiHa, and C-33A CCC pre-treated or not with HO-1 inhibitors, and the expression of IFN-γ, TNF-α, CD107a, Granzyme B, NKp44, NKp46, NKp30, and NKG2D was evaluated by FC.ResultsCCC lines HeLa, SiHa, and C-33A expressed HO-1. Inhibition of HO-1 in these cells increased the expression of IFN-γ and TNF-α in CD107a + NK-92 cells. We observed a reduction in the expression of NKG2D, NKp46, and NKp30 in NK cells co-cultured with HeLa and SiHa cells, and when HeLa and SiHa cells were pre-treated with the HO-1 inhibitors, the expression of NKG2D and NKp30 in NK cells was restored. We observed a similar effect in NK cells co-cultured with C-33A cells in NKp30 expression.ConclusionInhibition of HO-1 in CCC induces an increase in IFN-γ and TNF-α production in CD107a + NK-92 cells and restores NKG2D, NKp46 and NKp30 downmodulation in NK cells.

Highlights

Natural killer (NK) cells eliminate virus-infected and tumor cells through the release of perforins and granzymes; they produce Interferon gamma (IFN-γ) and Tumor necrosis factor alpha (TNF-α), which induce apoptosis in target cells
We can observe that the HeLa cell is the cancer cell line that expressed the highest percentage of cells positive to Heme oxygenase 1 (HO-1) (70.2% ± 4.9%) in comparison with SiHa and C-33A CCC (54.6% ± 1.5% and 30.3% ± 6.5%, respectively) (p
We evaluated viability in CCC treated with SnPP (25 μM) and Zinc protoporphyrin (ZnPP) (1 μM) HO-1 inhibitors and observed that these inhibitors did not affect the viability in these cells (Figure 1c)

Summary

Introduction

Natural killer (NK) cells eliminate virus-infected and tumor cells through the release of perforins and granzymes; they produce Interferon gamma (IFN-γ) and Tumor necrosis factor alpha (TNF-α), which induce apoptosis in target cells. Cells are influenced by the surrounding microenvironment and this process involves a selection mechanism of tumor cells, which initiate a number of signaling mechanisms to evade the immune response, as described in the hypothesis of immunoediting [16] Under certain circumstances, this interaction culminates in the eradication of tumor cells, as occurs the majority of times, or instead, in suppression of the immune response and tumor formation. Heme oxygenase 1 (HO-1) is the rate-limiting enzyme in heme catabolism and leads to three products: biliverdin; free iron, and carbon monoxide [19] It plays an important role in the modulation of inflammation, blocking the apoptotic process and antioxidant defense in the presence of any damage [20,21]. We evaluated HO-1 expression in Cervical cancer cells (CCC) and whether HO-1 inhibition enhanced the sensitivity of CCC to NK cells

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