A new small molecule that directly inhibits the DNA binding of NF-kappaB

Critical role of NF-κB in pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is one of the deadliest cancers, and in spite of intense efforts there are limited therapeutic options for patients with PDAC. PDACs harbor a high frequency of Kras mutations and other driver mutations that lead to altered signaling pathways and contribute to therapeutic resistance. Importantly, constitutive activation of nuclear factor κB (NF-κB) is frequently observed in PDAC. An increasing body of evidence suggests that both classical and non-classical NF-κB pathways play a crucial role in PDAC development and progression. In this review, we update the most recent advances regarding different aspects of NF-κB involvement in PDAC development and progression, emphasizing its potential as a therapeutic target and the need to discover pathway-specific cytosolic NF-κB regulators which could be used to design novel therapeutic strategies for PDAC.

A rapid and high-throughput quantitation assay of the nuclear factor κB activity using fluorescence correlation spectroscopy in the setting of clinical laboratories

Background

Transcription factor nuclear factor-κB (NF-κB) plays a key role in the regulation of immune responses to inflammation. However, convenient assay systems to quantitate the NF-κB activity level in a timely manner are not available in the setting of clinical laboratories. Therefore, we developed a novel and high-throughput quantitative assay based on fluorescence correlation spectroscopy (FCS) to detect the NF-κB activity level in cellular nuclear extracts and evaluated the performance of this method. The basic principle of this assay is to calculate the binding fraction of NF-κB to fluorescent-labeled DNA probes, which contain NF-κB binding sites.

Methods

Non-fluorescent competitive probes are employed to normalize the influence of the viscosity of the nuclear extracts between samples and to eliminate the influence of nonspecific binding of the fluorescent probes. To confirm accurate quantitation, human recombinant NF-κB p50 was mixed into U937 cell nuclear extracts, and the binding fraction of the fluorescent probes to NF-κB in the mixture was calculated for quantitation. To evaluate whether this method can be applied to measure the NF-κB activity in human lymphocytes, the NF-κB activity levels of systemic inflammatory response syndrome patients during perioperative periods were measured.

Results

The percentage recovery was 88.9%. The coefficients of variation of the intra-assay were approximately 10%. NF-κB activity levels during the perioperative period can were successfully measured. The assay time for the FCS measurement was within 20 minutes.

Conclusions

This assay system can be used to quantitate NF-κB activity levels in a timely manner in the setting of hospital laboratories.

Molecular docking and synthesis of novel quinazoline analogues as inhibitors of transcription factors NF-κB activation and their anti-cancer activities

NF-kB is a transcription factor protein complex that can be found in almost all animal cell types and is a key player in some cancers and inflammatory responses. It can enhance the proliferation rate, reduce apoptosis, as well as creating more blood flow to ensure the survival of cancer, thus blocking the NF-kB pathway has potential therapeutic benefit. We designed a series of compounds based on a quinazoline scaffold pharmacophore model which may have high binding affinity with the p50 subunit of NF-kB. The compound series with phenyl substitution at the 2 position of the quinazoline proved to be more effective at inhibiting NF-kB function both theoretically and experimentally. These compounds also reduce the proliferation of numerous tumor cell lines and the mean GI(50) for compound 2a is 2.88 μM against the NCI-60 cell line. At the same time, compound 2a can induce significant apoptosis in EKVX cell line at the concentration of 1 μM.

A cell-penetrating peptide suppresses inflammation by inhibiting NF-κB signaling

Nuclear factor-κB (NF-κB) is a central regulator of immune response and a potential target for developing anti-inflammatory agents. Mechanistic studies suggest that compounds that directly inhibit NF-κB DNA binding may block inflammation and the associated tissue damage. Thus, we attempted to discover peptides that could interfere with NF-κB signaling based on a highly conserved DNA-binding domain found in all NF-κB members. One such small peptide, designated as anti-inflammatory peptide-6 (AIP6), was characterized in the current study. AIP6 directly interacted with p65 and displayed an intrinsic cell-penetrating property. This peptide demonstrated significant anti-inflammatory effects in vitro and in vivo. In vitro, AIP6 inhibited the DNA-binding and transcriptional activities of the p65 NF-κB subunit as well as the production of inflammatory mediators in macrophages upon stimulation. Local administration of AIP6 significantly inhibited inflammation induced by zymosan in mice. Collectively, our results suggest that AIP6 is a promising lead peptide for the development of specific NF-κB inhibitors as potential anti-inflammatory agents.