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Updated: Nov 26, 2025
Application of Genetically Encoded Fluorescent Nitric Oxide (NO•) Probes, the geNOps, for Real-time Imaging of NO• Signals in Single Cells
Published on: March 16, 2017
Nitric Oxide Inhibits NF-κB-mediated Survival Signaling: Possible Role in Overcoming TRAIL Resistance
Joseph A Bauer1, Joseph A Lupica2, Joseph A Didonato3
1Nitric Oxide Services, LLC, St. John Paul II Center for Science Innovation, North Canton, OH, U.S.A.
Background/Aim:
Chemoresistance is a major consequence of multicycle chemotherapy and can be attributed to constitutive activation of pro-survival signaling pathways. Nitric oxide is a ubiquitous signaling molecule which has been shown to inhibit several pathways involved with survival signaling in cancer cells. We have previously demonstrated the anti-tumor activity of a nitric oxide-donor, nitrosylcobalamin (NO-Cbl), mediated by increased expression of tumor necrosis factor-related apoptosis-inducing ligand (Apo2L/TRAIL) and its receptors in human tumors. We also demonstrated that a functional Apo2L/TRAIL receptor is necessary for the induction of cell death by NO-Cbl and the Apo2L/TRAIL death receptor DR4 (TRAIL R1) is S-nitrosylated. The aim of the study was to examine the effects of nitric oxide (NO) on nuclear factor kappa B (NF-κB) and determine whether nitric oxide could sensitize drug-resistant melanomas to Apo2L/TRAIL via inhibition of NF-κB or inhibitor kappa B kinase (IKK).
Materials And Methods:
Antiproliferative effects of NO-Cbl and Apo2L/TRAIL were assessed in malignant melanomas and non-tumorigenic melanocyte and fibroblast cell lines. Athymic nude mice bearing human melanoma A375 xenografts were treated with NO-Cbl and Apo2L/TRAIL. Apoptosis was measured by the TUNEL assay. The activation status of NF-κB was established by assaying luciferase reporter activity, the phosphorylation status of IκBα, and in vitro IKK activity.
Results:
NO-Cbl sensitized Apo2L/TRAIL-resistant melanoma cell lines to growth inhibition by Apo2L/TRAIL, but had minimal effect on normal cell lines. NO-Cbl and Apo2L/TRAIL exerted synergistic anti-tumor activity against A375 xenografts. NO-Cbl suppressed Apo2L/TRAIL- and TNF-α-mediated activation of a transfected NF-κB-driven luciferase reporter. NO-Cbl inhibited IKK activation, characterized by decreased phosphorylation of IκBα.
Conclusion:
NO-Cbl treatment rendered Apo2L/TRAIL-resistant malignancies sensitive to the anti-tumor effects of Apo2L/TRAIL in vitro and in vivo. The use of nitric oxide to inhibit NF-κB and potentiate the effects of chemotherapeutic agents, such as Apo2L/TRAIL, represents a promising anti-cancer combination based on recent clinical investigations of anti-TRAIL antibodies for cancer treatment strategies.
Insights
Nitric oxide-cobalamin (NO-Cbl) overcomes chemoresistance in melanoma by inhibiting NF-κB signaling. This enhances the effectiveness of Apo2L/TRAIL therapy, making drug-resistant cancers sensitive to treatment.
Area of Science:
- Oncology
- Molecular Biology
- Cancer Therapeutics
Background:
- Chemoresistance is a significant challenge in cancer therapy, often driven by pro-survival signaling pathways.
- Nitric oxide (NO) is a signaling molecule with known inhibitory effects on cancer cell survival pathways.
- Previous studies showed NO-donor nitrosylcobalamin (NO-Cbl) has anti-tumor activity via Apo2L/TRAIL pathway modulation.
Purpose of the Study:
- To investigate the effect of nitric oxide (NO) on nuclear factor kappa B (NF-κB) signaling.
- To determine if NO can sensitize drug-resistant melanomas to Apo2L/TRAIL by inhibiting NF-κB or IKK.
- To explore NO-Cbl as a strategy to overcome chemoresistance.
Main Methods:
- Assessed antiproliferative effects of NO-Cbl and Apo2L/TRAIL on melanoma and normal cell lines.
- Evaluated synergistic anti-tumor activity in A375 xenografts in mice using NO-Cbl and Apo2L/TRAIL.
- Measured NF-κB activation via luciferase reporter assays, IκBα phosphorylation, and IKK activity.
Main Results:
- NO-Cbl sensitized Apo2L/TRAIL-resistant melanoma cells to growth inhibition, with minimal impact on normal cells.
- NO-Cbl and Apo2L/TRAIL demonstrated synergistic anti-tumor effects in vivo.
- NO-Cbl suppressed NF-κB activation and inhibited IKK activity.
Conclusions:
- NO-Cbl treatment restores sensitivity to Apo2L/TRAIL in resistant melanomas, both in vitro and in vivo.
- Inhibiting NF-κB with nitric oxide potentiates chemotherapy, like Apo2L/TRAIL.
- This combination therapy holds promise for cancer treatment, especially with emerging anti-TRAIL antibody strategies.
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