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BACKGROUND: Current influenza vaccines deliver satisfactory results in young people but are less effective in the elderly. Development of vaccines for an ever-increasing aging population has been an arduous challenge due to immunosenescence that impairs the immune response in the aged, both quantitatively and qualitatively. RESULTS: To potentially enhance vaccine efficacy in the elderly, we investigated the immunogenicity and cross-protection of influenza hemagglutinin virus-like particles (HA-VLP) incorporated with glycosylphosphatidylinositol (GPI)-anchored cytokine-adjuvants (GPI-GM-CSF and GPI-IL-12) via protein transfer in aged mice. Lung viral replication against homologous and heterologous influenza viruses was significantly reduced in aged mice after vaccination with cytokine incorporated VLPs (HA-VLP-Cyt) in comparison to HA-VLP alone. Enhanced IFN-γ+CD4+ and IFN-γ+CD8+ T cell responses were also observed in aged mice immunized with HA-VLP-Cyt when compared to HA-VLP alone. CONCLUSIONS: Cytokine-adjuvanted influenza HA-VLP vaccine induced enhanced protective response against homologous influenza A virus infection in aged mice. Influenza HA-VLP vaccine with GPI-cytokines also induced enhanced T cell responses correlating with better protection against heterologous infection in the absence of neutralizing antibodies. The results suggest that a vaccination strategy using cytokine-adjuvanted influenza HA-VLPs could be used to enhance protection against influenza A virus in the elderly.
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Several approaches have produced an effective vaccine against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Since millions of people are exposed to influenza virus and SARS-CoV-2, it is of great interest to develop a two-in-one vaccine that will be able to protect against infection of both viruses. We have developed a hybrid vaccine for SARS-CoV-2 and influenza viruses using influenza virus-like particles (VLP) incorporated by protein transfer with glycosylphosphatidylinositol (GPI)-anchored SARS-CoV-2 RBD fused to GM-CSF as an adjuvant. GPI-RBD-GM-CSF fusion protein was expressed in CHO-S cells, purified and incorporated onto influenza VLPs to develop the hybrid vaccine. Our results show that the hybrid vaccine induced a strong antibody response and protected mice from both influenza virus and mouse-adapted SARS-CoV-2 challenges, with vaccinated mice having significantly lower lung viral titers compared to naive mice. These results suggest that a hybrid vaccine strategy is a promising approach for developing multivalent vaccines to prevent influenza A and SARS-CoV-2 infections.
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BACKGROUND: PD-L1 is one of the major immune checkpoints which limits the effectiveness of antitumor immunity. Blockade of PD-L1/PD-1 has been a major improvement in the treatment of certain cancers, however, the response rate to checkpoint blockade remains low suggesting a need for new therapies. Metformin has emerged as a potential new drug for the treatment of cancer due to its effects on PD-L1 expression, T cell responses, and the immunosuppressive environment within tumors. While the benefits of metformin in combination with checkpoint blockade have been reported in animal models, little remains known about its effect on other types of immunotherapy. METHODS: Vaccine immunotherapy and metformin were administered to mice inoculated with tumors to investigate the effect of metformin and TMV vaccine on tumor growth, metastasis, PD-L1 expression, immune cell infiltration, and CD8 T cell phenotype. The effect of metformin on IFN-γ induced PD-L1 expression in tumor cells was assessed by flow cytometry, western blot, and RT-qPCR. RESULTS: We observed that tumors that respond to metformin and vaccine immunotherapy combination show a reduction in surface PD-L1 expression compared with tumor models that do not respond to metformin. In vitro assays showed that the effect of metformin on tumor cell PD-L1 expression was mediated in part by AMP-activated protein kinase signaling. Vaccination results in increased T cell infiltration in all tumor models, and this was not further enhanced by metformin. However, we observed an increased number of CD8 T cells expressing PD-1, Ki-67, Tim-3, and CD62L as well as increased effector cytokine production after treatment with metformin and tumor membrane vesicle vaccine. CONCLUSIONS: Our data suggest that metformin can synergize with vaccine immunotherapy to augment the antitumor response through tumor-intrinsic mechanisms and also alter the phenotype and function of CD8 T cells within the tumor, which could provide insights for its use in the clinic.
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Vacunas contra el Cáncer/uso terapéutico , Hipoglucemiantes/uso terapéutico , Inmunoterapia/métodos , Metformina/uso terapéutico , Animales , Antígeno B7-H1 , Vacunas contra el Cáncer/farmacología , Femenino , Humanos , Hipoglucemiantes/farmacología , Metformina/farmacología , RatonesRESUMEN
Dendritic cells (DCs) are the most effective antigen presenting cells for the development of T cell responses. The only FDA approved DC-based immunotherapy to date is Sipuleucel-T, which utilizes a fusion protein to stimulate DCs ex vivo with GM-CSF and simultaneously deliver the antigen PAP for prostate cancer. This approach is restricted by the breadth of immunity elicited to a single antigen, and to cancers that have a defined tumor associated antigen. Other multi-antigen approaches have been restricted by poor efficacy of vaccine adjuvants. We have developed a vaccine platform that consists of autologous DCs pulsed with cytokine-adjuvanted tumor membrane vesicles (TMVs) made from tumor tissue, that encapsulate the antigenic landscape of individual tumors. Here we test the efficacy of DCs pulsed with TMVs incorporated with glycolipid-anchored immunostimulatory molecules (GPI-ISMs) in HER2-positive and triple negative breast cancer murine models. Pulsing of DCs with TMVs containing GPI-ISMs results in superior uptake of vesicles, DC activation and cytokine production. Adaptive transfer of TMV-pulsed DCs to tumor bearing mice results in the inhibition of tumor growth, reduction in lung metastasis, and an increase in immune cell infiltration into the tumors. These observations suggest that DCs pulsed with TMVs containing GPI-GM-CSF and GPI-IL-12 can be further developed to be used as a personalized immunotherapy platform for cancer treatment.
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Antígenos de Neoplasias/inmunología , Citocinas/inmunología , Células Dendríticas/inmunología , Receptor ErbB-2/inmunología , Neoplasias de la Mama Triple Negativas/terapia , Traslado Adoptivo , Animales , Vacunas contra el Cáncer/inmunología , Vacunas contra el Cáncer/uso terapéutico , Línea Celular Tumoral , Células Cultivadas , Femenino , Humanos , Ratones , Ratones Endogámicos BALB C , Receptor ErbB-2/análisis , Neoplasias de la Mama Triple Negativas/inmunología , Neoplasias de la Mama Triple Negativas/patologíaRESUMEN
Triple-negative breast cancer (TNBC) afflicts women at a younger age than other breast cancers and is associated with a worse clinical outcome. This poor clinical outcome is attributed to a lack of defined targets and patient-to-patient heterogeneity in target antigens and immune responses. To address such heterogeneity, we tested the efficacy of a personalized vaccination approach for the treatment of TNBC using the 4T1 murine TNBC model. We isolated tumor membrane vesicles (TMVs) from homogenized 4T1 tumor tissue and incorporated glycosyl phosphatidylinositol (GPI)-anchored forms of the immunostimulatory B7-1 (CD80) and IL-12 molecules onto these TMVs to make a TMV vaccine. Tumor-bearing mice were then administered with the TMV vaccine either alone or in combination with immune checkpoint inhibitors. We show that TMV-based vaccine immunotherapy in combination with anti-CTLA-4 mAb treatment upregulated immunomodulatory cytokines in the plasma, significantly improved survival, and reduced pulmonary metastasis in mice compared to either therapy alone. The depletion of CD8+ T cells, but not CD4+ T cells, resulted in the loss of efficacy. This suggests that the vaccine acts via tumor-specific CD8+ T cell immunity. These results suggest TMV vaccine immunotherapy as a potential enhancer of immune checkpoint inhibitor therapies for metastatic triple-negative breast cancer.
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Vacunas contra el Cáncer , Neoplasias de la Mama Triple Negativas , Animales , Linfocitos T CD8-positivos/inmunología , Antígeno CTLA-4 , Línea Celular Tumoral , Humanos , Inmunoterapia , Interleucina-12 , Ratones , Neoplasias de la Mama Triple Negativas/terapiaRESUMEN
Immune checkpoint inhibitor (ICI) immunotherapy improved the survival of head and neck squamous cell carcinoma (HNSCC) patients. However, more than 80% of the patients are still resistant to this therapy. To test whether the efficacy of ICI therapy can be improved by vaccine-induced immunity, we investigated the efficacy of a tumor membrane-based vaccine immunotherapy in murine models of HNSCC. The tumors, grown subcutaneously, are used to prepare tumor membrane vesicles (TMVs). TMVs are then incorporated with glycolipid-anchored immunostimulatory molecules GPI-B7-1 and GPI-IL-12 by protein transfer to generate the TMV vaccine. This TMV vaccine inhibited tumor growth and improved the survival of mice challenged with SCCVII tumor cells. The tumor-free mice survived for several months, remained tumor-free, and were protected following a secondary tumor cell challenge, suggesting that the TMV vaccine induced an anti-tumor immune memory response. However, no synergy with anti-PD1 mAb was observed in this model. In contrast, the TMV vaccine was effective in inhibiting MOC1 and MOC2 murine oral cancer models and synergized with anti-PD1 mAb in extending the survival of tumor-bearing mice. These observations suggest that tumor tissue based TMV vaccines can be harnessed to develop an effective personalized immunotherapy for HNSCC that can enhance the efficacy of immune checkpoint inhibitors.
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The process of apoptosis is essential for maintaining the physiologic balance between cell death and cell growth. This complex process is executed by two major pathways that participate in activating an executioner mechanism leading to chromatin disintegration and nuclear fragmentation. Dysregulation of these pathways often contributes to cancer development and resistance to cancer therapy. Here, we review the most recent discoveries in apoptosis regulation and possible mechanisms for resensitizing tumor cells to therapy.
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Apoptosis , Antineoplásicos/farmacología , Antineoplásicos/uso terapéutico , Apoptosis/efectos de los fármacos , Proteínas Reguladoras de la Apoptosis/antagonistas & inhibidores , Proteínas Reguladoras de la Apoptosis/metabolismo , Caspasas/metabolismo , Humanos , Neoplasias/tratamiento farmacológico , Neoplasias/metabolismo , Neoplasias/patología , Receptores del Factor de Necrosis Tumoral/metabolismo , Ligando Inductor de Apoptosis Relacionado con TNF/metabolismo , Ligando Inductor de Apoptosis Relacionado con TNF/farmacología , Ligando Inductor de Apoptosis Relacionado con TNF/uso terapéutico , Factor de Necrosis Tumoral alfa/metabolismo , Receptor fas/metabolismoRESUMEN
Diffuse large B cell lymphoma (DLBCL) is the most common form of lymphoma in the United States. DLBCL comprises biologically distinct subtypes including germinal center-like (GCB) and activated-B-cell-like DLBCL (ABC). The most aggressive type, ABC-DLBCL, displays dysregulation of both canonical and noncanonical NF-κB pathway as well as genomic instability. Although, much is known about the tumorigenic roles of the canonical NF-kB pathway, the precise role of the noncanonical NF-kB pathway remains unknown. Here we show that activation of the noncanonical NF-κB pathway regulates chromosome stability, DNA damage response and centrosome duplication in DLBCL. Analysis of 92 DLBCL samples revealed that activation of the noncanonical NF-κB pathway is associated with low levels of DNA damage and centrosome amplification. Inhibiting the noncanonical pathway in lymphoma cells uncovered baseline DNA damage and prevented doxorubicin-induced DNA damage repair. In addition, it triggered centrosome amplification and chromosome instability, indicated by anaphase bridges, multipolar spindles and chromosome missegregation. We determined that the noncanonical NF-κB pathway execute these functions through the regulation of GADD45α and REDD1 in a p53-independent manner, while it collaborates with p53 to regulate cyclin G2 expression. Furthermore, this pathway regulates GADD45α, REDD1 and cyclin G2 through direct binding of NF-κB sites to their promoter region. Overall, these results indicate that the noncanonical NF-κB pathway plays a central role in maintaining genome integrity in DLBCL. Our data suggests that inhibition of the noncanonical NF-kB pathway should be considered as an important component in DLBCL therapeutic approach.
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Inestabilidad Cromosómica , Cromosomas Humanos/genética , Linfoma de Células B Grandes Difuso/genética , FN-kappa B/metabolismo , Transducción de Señal , Proteínas de Ciclo Celular/metabolismo , Línea Celular Tumoral , Núcleo Celular/genética , Centrosoma/metabolismo , Ciclina G2/metabolismo , Daño del ADN , Reparación del ADN/efectos de los fármacos , Doxorrubicina/farmacología , Humanos , Cariotipo , Datos de Secuencia Molecular , Proteínas Nucleares/metabolismo , Transducción de Señal/efectos de los fármacos , Factores de Transcripción/metabolismoRESUMEN
Prior work using allogeneic bone marrow transplantation (allo-BMT) models showed that peritransplant administration of flagellin, a toll-like receptor 5 (TLR5) agonist protected murine allo-BMT recipients from CMV infection while limiting graft-vs-host disease (GvHD). However, the mechanism by which flagellin-TLR5 interaction promotes anti-CMV immunity was not defined. Here, we investigated the anti-CMV immunity of NK cells in C57BL/6 (B6) mice treated with a highly purified cGMP grade recombinant flagellin variant CBLB502 (rflagellin) followed by murine CMV (mCMV) infection. A single dose of rflagellin administered to mice between 48 to 72 hours prior to MCMV infection resulted in optimal protection from mCMV lethality. Anti-mCMV immunity in rflagellin-treated mice correlated with a significantly reduced liver viral load and increased numbers of Ly49H+ and Ly49D+ activated cytotoxic NK cells. Additionally, the increased anti-mCMV immunity of NK cells was directly correlated with increased numbers of IFN-γ, granzyme B- and CD107a producing NK cells following mCMV infection. rFlagellin-induced anti-mCMV immunity was TLR5-dependent as rflagellin-treated TLR5 KO mice had â¼10-fold increased liver viral load compared with rflagellin-treated WT B6 mice. However, the increased anti-mCMV immunity of NK cells in rflagellin-treated mice is regulated indirectly as mouse NK cells do not express TLR5. Collectively, these data suggest that rflagellin treatment indirectly leads to activation of NK cells, which may be an important adjunct benefit of administering rflagellin in allo-BMT recipients.
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Citomegalovirus/inmunología , Células Asesinas Naturales/efectos de los fármacos , Células Asesinas Naturales/inmunología , Péptidos/farmacología , Proteínas Recombinantes/farmacología , Receptor Toll-Like 5/agonistas , Animales , Recuento de Células , Citocinas/metabolismo , Flagelina/genética , Células Asesinas Naturales/citología , Células Asesinas Naturales/metabolismo , Activación de Linfocitos/efectos de los fármacos , Ratones , Ratones Endogámicos C57BL , Subfamilia A de Receptores Similares a Lectina de Células NK/metabolismo , Péptidos/genética , Proteínas Recombinantes/genética , Factores de TiempoRESUMEN
The inhibitors of apoptosis (IAP) are important regulators of apoptosis. However, little is known about the capacity of Smac mimetics (IAP inhibitor) to overcome virally associated-lymphoma's (VAL) resistance to apoptosis. Here, we explored the pro-apoptotic effect of a novel Smac mimetic, RMT5265.2HCL (RMT) in VAL cells. RMT improved the sensitivity to apoptosis in EBV- and to some extend in HTLV-1- but not in HHV-8-VAL. Furthermore, we identified that RMT promotes caspase 3 and 9 cleavage by inhibiting XIAP and inducing the mitochondrial efflux of Smac and cytochrome C. This investigation further support exploring the use of Smac inhibitors in VAL.
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Antineoplásicos/farmacología , Apoptosis/efectos de los fármacos , Biomimética , Dipéptidos/farmacología , Péptidos y Proteínas de Señalización Intracelular , Linfoma de Células T/patología , Proteínas Mitocondriales , Tetrazoles/farmacología , Animales , Antineoplásicos/química , Antineoplásicos/uso terapéutico , Proteínas Reguladoras de la Apoptosis , Línea Celular Tumoral , Transformación Celular Viral/efectos de los fármacos , Citocromos c/metabolismo , Infecciones por Deltaretrovirus/complicaciones , Dipéptidos/química , Infecciones por Virus de Epstein-Barr/complicaciones , Células HEK293 , Herpesvirus Humano 4/fisiología , Virus Linfotrópico T Tipo 1 Humano/fisiología , Humanos , Péptidos y Proteínas de Señalización Intracelular/química , Péptidos y Proteínas de Señalización Intracelular/metabolismo , Linfoma de Células T/tratamiento farmacológico , Linfoma de Células T/etiología , Linfoma de Células T/metabolismo , Ratones , Ratones Transgénicos , Mitocondrias/efectos de los fármacos , Mitocondrias/metabolismo , Proteínas Mitocondriales/química , Proteínas Mitocondriales/metabolismo , Modelos Biológicos , Tetrazoles/química , Regulación hacia Arriba/efectos de los fármacos , Proteína Inhibidora de la Apoptosis Ligada a X/antagonistas & inhibidoresRESUMEN
Paraquat, N-methyl-4-phenyl-1,2,3,6 tetrahydropyridine, and rotenone have been shown to reproduce several features of Parkinson's disease in animal and cell culture models. Although these chemicals are known to perturb dopamine homeostasis and induce dopaminergic cell death, their molecular mechanisms of action are not well defined. We have previously shown that paraquat does not require functional dopamine transporter and does not inhibit mitochondrial complex I in order to mediate its toxic action (Richardson et al., 2005). In this study, we show that paraquat specifically oxidized the cytosolic form of thioredoxin and activated Jun N-terminal kinase (JNK), followed by caspase-3 activation. Conversely, 1-methyl-4-phenylpyridinium (MPP(+)) and rotenone oxidized the mitochondrial form of thioredoxin but did not activate JNK-mitogen-activated protein kinase and caspase-3. Loading cells with exogenous dopamine did not exacerbate the toxicity of any of these compounds. These data suggest that oxidative modification of cytosolic proteins is critical to paraquat toxicity, while oxidation of mitochondrial proteins is important for MPP(+) and rotenone toxicity. In addition, intracellular dopamine does not seem to exacerbate the toxicity of these dopaminergic neurotoxicants in this model.
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1-Metil-4-fenilpiridinio/toxicidad , Caspasa 3/metabolismo , Herbicidas/toxicidad , Insecticidas/toxicidad , Neuronas/efectos de los fármacos , Paraquat/toxicidad , Rotenona/toxicidad , Tiorredoxinas/metabolismo , Animales , Apoptosis/efectos de los fármacos , Línea Celular Tumoral , Supervivencia Celular/efectos de los fármacos , Dopamina/metabolismo , Proteínas de Transporte de Dopamina a través de la Membrana Plasmática/genética , Proteínas de Transporte de Dopamina a través de la Membrana Plasmática/metabolismo , Relación Dosis-Respuesta a Droga , Activación Enzimática/efectos de los fármacos , Humanos , Proteínas Quinasas JNK Activadas por Mitógenos/metabolismo , Proteínas Mitocondriales/metabolismo , Neuronas/metabolismo , Oxidación-Reducción , Trastornos Parkinsonianos/inducido químicamente , Trastornos Parkinsonianos/metabolismo , TransfecciónRESUMEN
2,3,5-Tris-(glutathion-S-yl)hydroquinone (TGHQ), a reactive metabolite of the nephrotoxicant hydroquinone, induces the ROS-dependent activation of MAPKs, followed by histone H3 phosphorylation and oncotic cell death in renal proximal tubule epithelial cells (LLC-PK(1)). Cell death and histone H3 phosphorylation are attenuated by pharmacological inhibition of p38 MAPK or ERK1/2 pathways. Because TGHQ, but not epidermal growth factor (EGF), induces histone H3 phosphorylation and cell death in LLC-PK(1) cells, we hypothesized that there are differences in the mechanisms by which TGHQ and EGF induce activation of the EGF receptor (EGFR). We therefore compared the relative ability of TGHQ, H(2)O(2), and EGF to activate EGFR and MAPKs and found that p38 MAPK activation is EGFR independent, whereas ERK1/2 activation occurs mainly through EGFR activation. TGHQ, H(2)O(2), and EGF induce different EGFR tyrosine phosphorylation profiles that likely influence the subsequent differential kinetics of MAPK activation. We next transfected LLC-PK(1) cells with a dominant negative p38 MAPK-expressing plasmid (pcDNA3-DNp38). TGHQ failed to induce phosphorylation of p38 MAPK and its substrate, MK-2, in pcDNA3-DNp38-transfected cells, indicating loss of function of p38 MAPK. In untransfected, pcDNA3 or pcDNA3-p38 (native)-transfected LLC-PK(1) cells, Hsp27 was intensively phosphorylated after TGHQ treatment, whereas in pcDNA3-DNp38-transfected cells, TGHQ failed to induce Hsp27 phosphorylation. Thus EGFR-independent p38 MAPK and EGFR-dependent ERK1/2 activation by TGHQ lead to the activation of two downstream signaling factors, i.e., histone H3 and Hsp27 phosphorylation, which have in common the potential ability to remodel chromatin.
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Genes erbB-1/fisiología , Riñón/citología , Proteínas Quinasas Activadas por Mitógenos/metabolismo , Especies Reactivas de Oxígeno/toxicidad , Animales , Western Blotting , Muerte Celular/efectos de los fármacos , Células Cultivadas , Activación Enzimática/fisiología , Factor de Crecimiento Epidérmico/farmacología , Proteínas de Choque Térmico/metabolismo , Histonas/metabolismo , Peróxido de Hidrógeno/farmacología , Riñón/enzimología , Células LLC-PK1 , Fosforilación , Porcinos , Proteínas Quinasas p38 Activadas por MitógenosRESUMEN
The tuberous sclerosis-2 (Tsc-2) gene is a suppressor of renal tumorigenesis and an early target of reactive oxygen species-induced renal cancer. Tuberin, the protein product of the Tsc-2 gene, participates in the regulation of cell proliferation, although the mechanism by which it suppresses proliferation is unknown. Quinol-thioether-transformed rat renal epithelial (QT-RRE) cell lines, derived from quinol-thioether-transformed primary renal epithelial cells from Eker rats, lack tuberin expression due to loss of heterozygosity of the Tsc-2 gene. These cell lines were used to examine the mechanism by which tuberin exerts its antiproliferative action. Loss of tuberin function correlates with high ERK activity (39), which could contribute to the formation of renal tumors. In this study, we sought to identify possible downstream effectors regulated by tuberin, using QT-RRE cells transfected with Tsc-2 cDNA to restore tuberin expression. Constitutively high ERK, B-Raf, and Raf-1 activities were observed in QT-RRE cells. However, restoration of tuberin expression in QT-RRE cells by transient transfection with Tsc-2 cDNA substantially decreased both ERK and B-Raf activity, with only modest changes in Raf-1 activity, suggesting tuberin functions as an upstream negative regulator of the ERK pathway. High ERK activity was not mediated through EGF receptor activation, but treatment with genistein demonstrated that protein kinases are involved in ERK cascade activation. The data indicate that loss of tuberin results in the upregulation of the ERK signaling pathway with subsequent increases in new DNA synthesis, and ultimately, tumor formation.
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Proteínas Quinasas Activadas por Mitógenos/metabolismo , Proteínas Proto-Oncogénicas c-raf/metabolismo , Proteínas Represoras/metabolismo , Animales , Línea Celular Transformada , ADN Complementario , Regulación hacia Abajo , Expresión Génica , Células LLC-PK1 , Sistema de Señalización de MAP Quinasas/fisiología , Proteínas Quinasas Activadas por Mitógenos/genética , Proteínas Proto-Oncogénicas B-raf , Ratas , Ratas Mutantes , Proteínas Represoras/genética , Porcinos , Transfección , Proteína 2 del Complejo de la Esclerosis Tuberosa , Proteínas Supresoras de TumorRESUMEN
Extracellular signal-regulated kinases (ERK1/2), c-Jun N-terminal kinases (JNK/SAPK), and p38 mitogen-activated protein kinase (MAPK) were all rapidly activated in a ROS-dependent manner during 2,3,5-tris-(glutathion-S-yl)hydroquinone (TGHQ)-mediated oxidative stress and oncotic cell death in renal proximal tubule epithelial cells (LLC-PK1). TGHQ-induced phosphorylation of ERK1/2 and JNK MAPKs required epidermal growth factor receptor (EGFR) activation, whereas p38 MAPK activation was EGFR independent. In contrast to their established roles in cell survival, TGHQ-activated ERK1/2 and p38 MAPK (but not JNK) appear to contribute to cell death, since inhibition of ERK1/2 or p38 MAPKs with PD098059 or SB202190 respectively, attenuated TGHQ-mediated cell death. TGHQ increased AP-1 and NFkappaB DNA-binding activity, but whereas pharmacological inhibition of ERK1/2 or p38 MAPKs attenuated AP-1 DNA binding activity, it potentiated TGHQ-mediated NFkappaB activation. Consistent with a role for NFkappaB activation in the cytoprotective response to ROS in renal epithelial cells, an anti-NFkappaB peptide SN50 suppressed the protective effects of ERK inhibition (PD098059 treatment). The data provide evidence that the activation of MAPKs by ROS in renal epithelial cells plays an important role in oncotic cell death, and NF-kB is involved in the cytoprotective effects of PD098059.