Subunit-Specific Role of NF-κB in Cancer

Kaltschmidt B, Greiner J, Kadhim H, Kaltschmidt C. Subunit-Specific Role of NF-κB in Cancer. Biomedicines. 2018;6(2): 44.The transcription factor NF-kB is a key player in inflammation, cancer development, and progression. NF-kB stimulates cell proliferation, prevents apoptosis, and could promote tumor angiogenesis as well as metastasis. Extending the commonly accepted role of NF-kB in cancer formation and progression, different NF-kB subunits have been shown to be active and of particular importance in distinct types of cancer. Here, we summarize overexpression data of the NF-kB subunits RELA, RELB, and c-REL (referring to the v-REL, which is the oncogene of Reticuloendotheliosis virus strain T) as well as of their upstream kinase inhibitor, namely inhibitor of kB kinases (IKK), in different human cancers, assessed by database mining. These data argue against a universal mechanism of cancer-mediated activation of NF-kB, and suggest a much more elaborated mode of NF-kB regulation, indicating a tumor type-specific upregulation of the NF-kB subunits. We further discuss recent findings showing the diverse roles of NF-kB signaling in cancer development and metastasis in a subunit-specific manner, emphasizing their specific transcriptional activity and the role of autoregulation. While non-canonical NF-kB RELB signaling is described to be mostly present in hematological cancers, solid cancers reveal constitutive canonical NF-kB RELA or c-REL activity. Providing a linkage to cancer therapy, we discuss the recently described pivotal role of NF-kB c-REL in regulating cancer-targeting immune responses. In addition, current strategies and ongoing clinical trials are summarized, which utilize genome editing or drugs to inhibit the NF-kB subunits for cancer treatment

Cyclooxygenase-2 is a neuronal target gene of NF-κB

BACKGROUND: NF-κB is implicated in gene regulation involved in neuronal survival, inflammmatory response and cancer. There are relatively few neuronal target genes of NF-κB characterized. RESULTS: We have identified the neuronal cyclooxygenase-2 (COX-2) as a NF-κB target gene. In organotypic hippocampal slice cultures constitutive NF-κB activity was detected, which was correlated with high anti-COX-2 immunoreactivity. Aspirin a frequently used painkiller inhibits neuronal NF-κB activity in organotypic cultures resulting in a strong inhibition of the NF-κB target gene COX-2. Based on these findings, the transcriptional regulation of COX-2 by NF-κB was investigated. Transient transfections showed a significant increase of COX-2 promoter activity upon stimulation with PMA, an effect which could be obtained also by cotransfection of the NF-κB subunits p65 and p50. In the murine neuroblastoma cell line NB-4, which is characterized by constitutive NF-κB activity, COX-2 promoter activity could not be further increased with PMA or TNF. Constitutive promoter activity could be repressed upon cotransfection of the inhibitory subunit IκB-α. EMSA and mutational analysis conferred the regulatory NF-κB activity to the promoter distal κB-site in the human COX-2 promoter. CONCLUSIONS: NF-κB regulates neuronal COX-2 gene expression, and acts as an upstream target of Aspirin. This extends Aspirin's mode of action from a covalent modification of COX-2 to the upstream regulation of COX-2 gene expression in neurons

NF-KappaB in Long-Term Memory and Structural Plasticity in the Adult Mammalian Brain

Kaltschmidt B, Kaltschmidt C. NF-KappaB in Long-Term Memory and Structural Plasticity in the Adult Mammalian Brain. Frontiers in Molecular Neuroscience. 2015;8: 69.The transcription factor nuclear factor kappaB (NF-κB) is a well-known regulator of inflammation, stress, and immune responses as well as cell survival. In the nervous system, NF-κB is one of the crucial components in the molecular switch that converts short- to long-term memory—a process that requires de novo gene expression. Here, the researches published on NF-κB and downstream target genes in mammals will be reviewed, which are necessary for structural plasticity and long-term memory, both under normal and pathological conditions in the brain. Genetic evidence has revealed that NF-κB regulates neuroprotection, neuronal transmission, and long-term memory. In addition, after genetic ablation of all NF-κB subunits, a severe defect in hippocampal adult neurogenesis was observed during aging. Proliferation of neural precursors is increased; however, axon outgrowth, synaptogenesis, and tissue homeostasis of the dentate gyrus are hampered. In this process, the NF-κB target gene PKAcat and other downstream target genes such as Igf2 are critically involved. Therefore, NF-κB activity seems to be crucial in regulating structural plasticity and replenishment of granule cells within the hippocampus throughout the life. In addition to the function of NF-κB in neurons, we will discuss on a neuroinflammatory role of the transcription factor in glia. Finally, a model for NF-κB homeostasis on the molecular level is presented, in order to explain seemingly the contradictory, the friend or foe, role of NF-κB in the nervous system

Tumor necrosis factor alpha induced proliferation of adult neural stem cells is mediated via NF-κB

Widera D, Mikenberg I, Elvers M, Kaltschmidt C, Kaltschmidt B. Tumor necrosis factor alpha triggers proliferation of adult neural stem cells via IKK/NF-kappa B signaling. BMC NEUROSCIENCE. 2006;8(Suppl 1):P1

Tumor necrosis factor α triggers proliferation of adult neural stem cells via IKK/NF-κB signaling

BACKGROUND: Brain inflammation has been recognized as a complex phenomenon with numerous related aspects. In addition to the very well-described neurodegenerative effect of inflammation, several studies suggest that inflammatory signals exert a potentially positive influence on neural stem cell proliferation, migration and differentiation. Tumor necrosis factor alpha (TNF-α) is one of the best-characterized mediators of inflammation. To date, conclusions about the action of TNF on neural stem or progenitor cells (NSCs, NPCs) have been conflicting. TNF seems to activate NSC proliferation and to inhibit their differentiation into NPCs. The purpose of the present study was to analyze the molecular signal transduction mechanisms induced by TNF and resulting in NSC proliferation. RESULTS: Here we describe for the first time the TNF-mediated signal transduction cascade in neural stem cells (NSCs) that results in increased proliferation. Moreover, we demonstrate IKK-α/β-dependent proliferation and markedly up-regulated cyclin D1 expression after TNF treatment. The significant increase in proliferation in TNF-treated cells was indicated by increased neurosphere volume, increased bromodeoxyuridin (BrdU) incorporation and a higher total cell number. Furthermore, TNF strongly activated nuclear factor-kappa B (NF-κB) as measured by reporter gene assays and by an activity-specific antibody. Proliferation of control and TNF-treated NSCs was strongly inhibited by expression of the NF-κB super-repressor IκB-AA1. Pharmacological blockade of IκB ubiquitin ligase activity led to comparable decreases in NF-κB activity and proliferation. In addition, IKK-β gene product knock-down via siRNA led to diminished NF-κB activity, attenuated cyclin D1 expression and finally decreased proliferation. In contrast, TGFβ-activated kinase 1 (TAK-1) is partially dispensable for TNF-mediated and endogenous proliferation. Understanding stem cell proliferation is crucial for future regenerative and anti-tumor medicine. CONCLUSION: TNF-mediated activation of IKK-β resulted in activation of NF-κB and was followed by up-regulation of the bona-fide target gene cyclin D1. Activation of the canonical NF-κB pathway resulted in strongly increased proliferation of NSCs

On the cytotoxicity of HCR-NTPase in the neuroblastoma cell line SH-SY5Y

Pasdziernik M, Kaltschmidt B, Kaltschmidt C, Klinger C, Kaufmann M. On the cytotoxicity of HCR-NTPase in the neuroblastoma cell line SH-SY5Y. BMC Research Notes. 2009;2(1):102.Background: The human cancer-related nucleoside triphosphatase (HCR-NTPase) is overexpressed in several tumour tissues including neuroblastoma. HCR-NTPase is an enzyme exhibiting a slow in vitro activity in hydrolysing nucleosidetriphosphates. However, its in vivo function is still unknown. To learn more about the physiological role of HCR-NTPase, we both overexpressed and silenced it in the neuroblastoma cell line SH-SY5Y. Findings: No effect was observed when the expression of endogenously expressed HCR-NTPase in the cells was silenced by RNA interference. On the other hand, overexpression of HCR-NTPase led to cytotoxicity of the protein in SH-SY5Y cells. Even if the catalytic essential amino acid glutamate 114 was replaced by alanine (E114A-HCR-NTPase), the protein remained cytotoxic. The results could be confirmed by successfully rescuing the cells via RNA interference. Conclusion: Although expressed in several tumours, at least in SH-SY5Y, HCR-NTPase is not essential for the cells to survive. Increased levels of the protein lead to cytotoxicity due to physical intracellular interactions rather than hydrolysis of nucleosidetriphosphates by its intrinsic residual enzymatic activity

Preparation of Terpenoid-Invasomes with Selective Activity against S. aureus and Characterization by Cryo Transmission Electron Microscopy

Kaltschmidt B, Ennen I, Greiner J, et al. Preparation of Terpenoid-Invasomes with Selective Activity against S. aureus and Characterization by Cryo Transmission Electron Microscopy. Biomedicines. 2020;8(5): 105.Terpenoids are natural plant-derived products that are applied to treat a broad range of human diseases, such as airway infections and inflammation. However, pharmaceutical applications of terpenoids against bacterial infection remain challenging due to their poor water solubility. Here, we produce invasomes encapsulating thymol, menthol, camphor and 1,8-cineol, characterize them via cryo transmission electron microscopy and assess their bactericidal properties. While control- and cineol-invasomes are similarly distributed between unilamellar and bilamellar vesicles, a shift towards unilamellar invasomes is observable after encapsulation of thymol, menthol or camphor. Thymol- and camphor-invasomes show a size reduction, whereas menthol-invasomes are enlarged and cineol-invasomes remain unchanged compared to control. While thymol-invasomes lead to the strongest growth inhibition of S. aureus, camphor- or cineol-invasomes mediate cell death and S. aureus growth is not affected by menthol-invasomes. Flow cytometric analysis validate that invasomes comprising thymol are highly bactericidal to S. aureus. Notably, treatment with thymol-invasomes does not affect survival of Gram-negative E. coli. In summary, we successfully produce terpenoid-invasomes and demonstrate that particularly thymol-invasomes show a strong selective activity against Gram-positive bacteria. Our findings provide a promising approach to increase the bioavailability of terpenoid-based drugs and may be directly applicable for treating severe bacterial infections such as methicillin-resistant S. aureus

Interaction of adult human neural crest-derived stem cells with a nanoporous titanium surface is sufficient to induce their osteogenic differentiation

Osteogenic differentiation of various adult stem cell populations such as neural crest-derived stem cells is of great interest in the context of bone regeneration. Ideally, exogenous differentiation should mimic an endogenous differentiation process, which is partly mediated by topological cues. To elucidate the osteoinductive potential of porous substrates with different pore diameters (30 nm, 100 nm), human neural crest-derived stem cells isolated from the inferior nasal turbinate were cultivated on the surface of nanoporous titanium covered membranes without additional chemical or biological osteoinductive cues. As controls, flat titanium without any topological features and osteogenic medium was used. Cultivation of human neural crest-derived stem cells on 30 nm pores resulted in osteogenic differentiation as demonstrated by alkaline phosphatase activity after seven days as well as by calcium deposition after 3 weeks of cultivation. In contrast, cultivation on flat titanium and on membranes equipped with 100 nm pores was not sufficient to induce osteogenic differentiation. Moreover, we demonstrate an increase of osteogenic transcripts including Osterix, Osteocalcin and up-regulation of Integrin β1 and α2 in the 30 nm pore approach only. Thus, transplantation of stem cells pre-cultivated on nanostructured implants might improve the clinical outcome by support of the graft adherence and acceleration of the regeneration process

Sexualdimorphismen adulter Stammzellen

Merten M, Greiner J, Kaltschmidt C, Kaltschmidt B. Sexualdimorphismen adulter Stammzellen. BIOspektrum. 2020;26(1):50-53.Neurodegenerative diseases like Parkinson’s disease differ between the sexes in severity and occurrence. Next to hormons, increasing evidence suggests stem cell-intrinsic mechanisms to account for pathologic sex-specific differences. Here, we discuss such sex-related intrinsic mechanisms and sex-specific differences in adult stem cells, neuronal development and neuroprotection. The reviewed observations emphazise the importance of considering sexual dimorphisms for medical treatment strategies