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Effect of nuclear factor kappaB inhibition on tumor cell sensitivity to natural killer-mediated cytolytic function
F Mami-Chouaib1, M Ameyar, G Dorothée
1Institut Gustave Roussy, Unité 487 INSERM "Cytokines et Immunologie des Tumeurs Humaines", Villejuif, France.
Abstract:
Inhibition of the transcription factor NF-kappaB has been reported to increase cell sensitivity to TNF and some cytotoxic drugs. We investigated the effect of NK-kappaB inhibition on the susceptibility of tumor cells to freshly isolated, nonactivated, human NK cells and to a TCRgamma/delta T cell clone displaying an MHC-unrestricted "NK-like" lysis. Using electrophoretic mobility shift assay, we first demonstrated that NF-kappaB/DNA binding activity was induced in target cells following coculture with NK cells or TCRgamma/delta T cell clone. To investigate the effect of target cell NF-kappaB inhibition on NK-mediated lysis, we blocked NF-kappaB translocation by introducing a human cDNA coding for a mutated IkappaB-alpha. Interestingly, our results indicated that inhibition of NF-kappaB did not induce any increase in either granzyme-dependent non-MHC-restricted cytotoxicity mediated by fresh non-stimulated NK cells and by TCR gamma/delta T cell clone or in CD95-mediated lysis. These results emphasize that NF-kappaB expressed in target cells does not play a role in the molecular process related to the control of target cell susceptibility to NK-mediated lysis and suggest that the NF-kappaB pathway is not a general mechanism for controlling the cytotoxic response.
Insights
Inhibiting the transcription factor nuclear factor-kappa B (NF-kappaB) did not enhance tumor cell susceptibility to natural killer (NK) cells or T cell clones. NF-kappaB does not appear to be a general mechanism controlling cytotoxic responses against tumor cells.
Area of Science:
- Immunology
- Molecular Biology
- Cell Biology
Background:
- Nuclear factor-kappa B (NF-kappaB) inhibition reportedly increases tumor cell sensitivity to TNF and certain cytotoxic drugs.
- The role of NF-kappaB in tumor cell susceptibility to natural killer (NK) cells and T cell-mediated cytotoxicity remains unclear.
Purpose of the Study:
- To investigate the impact of NF-kappaB inhibition on tumor cell susceptibility to human NK cells and TCRgamma/delta T cell clones.
- To determine if NF-kappaB plays a role in NK-mediated lysis and CD95-mediated apoptosis.
Main Methods:
- Electrophoretic mobility shift assay (EMSA) to detect NF-kappaB/DNA binding activity.
- Introduction of mutated IkappaB-alpha cDNA to inhibit NF-kappaB translocation.
- Assessment of granzyme-dependent cytotoxicity and CD95-mediated lysis.
Main Results:
- NF-kappaB/DNA binding activity was induced in target cells upon co-culture with NK cells or TCRgamma/delta T cell clones.
- Inhibition of NF-kappaB did not increase susceptibility to granzyme-dependent cytotoxicity mediated by NK cells or TCRgamma/delta T cell clones.
- NF-kappaB inhibition did not affect CD95-mediated lysis.
Conclusions:
- NF-kappaB in target cells does not influence susceptibility to NK-mediated lysis.
- The NF-kappaB pathway is not a general mechanism controlling target cell sensitivity to cytotoxic responses.