Comparative analysis of T-cell costimulation and CD43 activation reveals novel signaling pathways and target genes

The glycoimmune checkpoint receptor Siglec-7 interacts with T-cell ligands and regulates T-cell activation

Siglec-7 (sialic acid-binding immunoglobulin-like lectin 7) is a glycan-binding immune receptor that is emerging as a significant target of interest for cancer immunotherapy. The physiological ligands that bind Siglec-7, however, remain incompletely defined. In this study, we characterized the expression of Siglec-7 ligands on peripheral immune cell subsets and assessed whether Siglec-7 functionally regulates interactions between immune cells. We found that disialyl core 1 O-glycans are the major immune ligands for Siglec-7 and that these ligands are particularly highly expressed on naïve T-cells. Densely glycosylated sialomucins are the primary carriers of these glycans, in particular a glycoform of the cell-surface marker CD43. Biosynthesis of Siglec-7-binding glycans is dynamically controlled on different immune cell subsets through a genetic circuit involving the glycosyltransferase GCNT1. Siglec-7 blockade was found to increase activation of both primary T-cells and antigen-presenting dendritic cells in vitro, indicating that Siglec-7 binds T-cell glycans to regulate intraimmune signaling. Finally, we present evidence that Siglec-7 directly activates signaling pathways in T-cells, suggesting a new biological function for this receptor. These studies conclusively demonstrate the existence of a novel Siglec-7-mediated signaling axis that physiologically regulates T-cell activity. Going forward, our findings have significant implications for the design and implementation of therapies targeting immunoregulatory Siglec receptors.

Nef-Mediated CD3-TCR Downmodulation Dampens Acute Inflammation and Promotes SIV Immune Evasion

The inability of Nef to downmodulate the CD3-T cell receptor (TCR) complex distinguishes HIV-1 from other primate lentiviruses and may contribute to its high virulence. However, the role of this Nef function in virus-mediated immune activation and pathogenicity remains speculative. Here, we selectively disrupted this Nef activity in SIV_mac239 and analyzed the consequences for the virological, immunological, and clinical outcome of infection in rhesus macaques. The inability to downmodulate CD3-TCR does not impair viral replication during acute infection but is associated with increased immune activation and antiviral gene expression. Subsequent early reversion in three of six animals suggests strong selective pressure for this Nef function and is associated with high viral loads and progression to simian AIDS. In the absence of reversions, however, viral replication and the clinical course of infection are attenuated. Thus, Nef-mediated downmodulation of CD3 dampens the inflammatory response to simian immunodeficiency virus (SIV) infection and seems critical for efficient viral immune evasion.

HIV-1 lacks the CD3 downmodulation function of Nef that is otherwise conserved in primate lentiviruses. Joas et al. disrupted this Nef activity in SIV_mac239 and show that Nef-mediated downmodulation of CD3 dampens inflammatory responses to SIV. This promotes effective immune evasion and maintenance of high viral loads in infected rhesus macaques.

An alternative mode of CD43 signal transduction activates pro-survival pathways of T lymphocytes

CD43 is one of the most abundant co-stimulatory molecules on a T-cell surface; it transduces activation signals through its cytoplasmic domain, contributing to modulation of the outcome of T-cell responses. The aim of this study was to uncover new signalling pathways regulated by this sialomucin. Analysis of changes in protein abundance allowed us to identify pyruvate kinase isozyme M2 (PKM2), an enzyme of the glycolytic pathway, as an element potentially participating in the signalling cascade resulting from the engagement of CD43 and the T-cell receptor (TCR). We found that the glycolytic activity of this enzyme was not significantly increased in response to TCR+CD43 co-stimulation, but that PKM2 was tyrosine phosphorylated, suggesting that it was performing moonlight functions. We report that phosphorylation of both Y¹⁰⁵ of PKM2 and of Y⁷⁰⁵ of signal transducer and activator of transcription 3 was induced in response to TCR+CD43 co-stimulation, resulting in activation of the mitogen-activated protein kinase kinase 5/extracellular signal-regulated kinase 5 (MEK5/ERK5) pathway. ERK5 and the cAMP response element binding protein (CREB) were activated, and c-Myc and nuclear factor-κB (p65) nuclear localization, as well as Bad phosphorylation, were augmented. Consistent with this, expression of human CD43 in a murine T-cell hybridoma favoured cell survival. Altogether, our data highlight novel signalling pathways for the CD43 molecule in T lymphocytes, and underscore a role for CD43 in promoting cell survival through non-glycolytic functions of metabolic enzymes.

Engagement of distinct epitopes on CD43 induces different co-stimulatory pathways in human T cells

Co‐receptors, being either co‐stimulatory or co‐inhibitory, play a pivotal role in T‐cell immunity. Several studies have indicated that CD43, one of the abundant T‐cell surface glycoproteins, acts not only as a potent co‐receptor but also as a negative regulator for T‐cell activation. Here we demonstrate that co‐stimulation of human peripheral blood (PB) T cells through two distinct CD43 epitopes recognized by monoclonal antibodies (mAb) CD43‐6E5 (T_6E5‐act) and CD43‐10G7 (T_10G7‐act) potently induced T‐cell proliferation. However, T‐cell co‐stimulation through two CD43 epitopes differentially regulated activation of nuclear factor of activated T cells (NFAT) and nuclear factor‐κB (NF‐κB) transcription factors, T‐cell cytokine production and effector function. T_6E5‐act produced high levels of interleukin‐22 (IL‐22) and interferon‐γ (IFN‐γ) similar to T cells activated via CD28 (T_CD28‐act), whereas T_10G7‐act produced low levels of inflammatory cytokines but higher levels of regulatory cytokines transforming growth factor‐β (TGF‐β) and interleukin‐35 (IL‐35). Compared with T_6E5‐act or to T_CD28‐act, T_10G7‐act performed poorly in response to re‐stimulation and further acquired a T‐cell suppressive function. T_10G7‐act did not directly inhibit proliferation of responder T cells, but formed stable heterotypic clusters with dendritic cells (DC) via CD2 to constrain activation of responder T cells. Together, our data demonstrate that CD43 is a unique and polarizing regulator of T‐cell function.

Fine-tuning of NFκB by glycogen synthase kinase 3β directs the fate of glomerular podocytes upon injury

NFκB is regulated by a myriad of signaling cascades including glycogen synthase kinase (GSK) 3β and plays a Janus role in podocyte injury. In vitro, lipopolysaccharide or adriamycin elicited podocyte injury and cytoskeletal disruption, associated with NFκB activation and induced expression of NFκB target molecules, including pro-survival Bcl-xL and podocytopathic mediators like MCP-1, cathepsin L and B7-1. Broad range inhibition of NFκB diminished the expression of all NFκB target genes, restored cytoskeleton integrity, but potentiated apoptosis. In contrast, blockade of GSK3β by lithium or TDZD-8, mitigated the expression of podocytopathic mediators, ameliorated podocyte injury, but barely affected Bcl-xL expression or sensitized apoptosis. Mechanistically, GSK3β was sufficient and essential for RelA/p65 phosphorylation specifically at serine 467, which specifies the expression of selective NFκB target molecules, including podocytopathic mediators, but not Bcl-xL. In vivo, lithium or TDZD-8 therapy improved podocyte injury and proteinuria in mice treated with lipopolysaccharide or adriamycin, concomitant with suppression of podocytopathic mediators but retained Bcl-xL in glomerulus. Broad range inhibition of NFκB conferred similar but much weakened antiproteinuric and podoprotective effects accompanied with a blunted glomerular expression of Bcl-xL and marked podocyte apoptosis. Thus, the GSK3β dictated fine-tuning of NFκB may serve as a novel therapeutic target for podocytopathy.

CD43-mediated IFN-γ production by CD8+ T cells promotes abdominal aortic aneurysm in mice

CD43 is a glycosylated surface protein abundantly expressed on lymphocytes. Its role in immune responses has been difficult to clearly establish, with evidence supporting both costimulatory and inhibitory functions. In addition, its contribution to disease pathogenesis remains elusive. Using a well-characterized murine model of elastase-induced abdominal aortic aneurysm (AAA) that recapitulates many key features of the human disease, we established that the presence of CD43 on T cells is required for AAA formation. Moreover, we found that IFN-γ-producing CD8(+) T cells, but not CD4(+) T cells, promote the development of aneurysm by enhancing cellular apoptosis and matrix metalloprotease activity. Reconstitution with IFN-γ-producing CD8(+) T cells or recombinant IFN-γ promotes the aneurysm phenotype in CD43(-/-) mice, whereas IFN-γ antagonism abrogates disease in wild-type animals. Furthermore, we showed that the presence of CD43 with an intact cytoplasmic domain capable of binding to ezrin-radixin-moesin cytoskeletal proteins is essential for optimal in vivo IFN-γ production by T cells and aneurysm formation. We have thus identified a robust physiologic role for CD43 in a relevant animal model and established an important in vivo function for CD43-dependent regulation of IFN-γ production. These results further suggest that IFN-γ antagonism or selective blockade of CD43(+)CD8(+) T cell activities merits further investigation for immunotherapy in AAA.

T cells modulate glycans on CD43 and CD45 during development and activation, signal regulation, and survival

Glycosylation affects many essential T cell processes and is intrinsically controlled throughout the lifetime of a T cell. CD43 and CD45 are the two most abundant glycoproteins on the T cell surface and are decorated with O- and N-glycans. Global T cell glycosylation and specific glycosylation of CD43 and CD45 are modulated during thymocyte development and T cell activation; T cells control the type and abundance of glycans decorating CD43 and CD45 by regulating expression of glycosyltransferases and glycosidases. Additionally, T cells regulate glycosylation of CD45 by expressing alternatively spliced isoforms of CD45 that have different glycan attachment sites. The glycophenotype of CD43 and CD45 on T cells influences how T cells interact with the extracellular environment, including how T cells interact with endogenous lectins. This review focuses on changes in glycosylation of CD43 and CD45 occurring throughout T cell development and activation and the role that glycosylation plays in regulating T cell processes, such as migration, T cell receptor signaling, and apoptosis.

CD43 Expression Regulated by IL-12 Signaling Is Associated with Survival of CD8 T Cells

Background

In addition to TCR and costimulatory signals, cytokine signals are required for the differentiation of activated CD8 T cells into memory T cells and their survival. Previously, we have shown that IL-12 priming during initial antigenic stimulation significantly enhanced the survival of activated CD8 T cells and increased the memory cell population. In the present study, we analyzed the mechanisms by which IL-12 priming contributes to activation and survival of CD8 T cells.

Methods

We observed dramatically decreased expression of CD43 in activated CD8 T cells by IL-12 priming. We purified CD43^lo and CD43^hi cells after IL-12 priming and analyzed the function and survival of each population both in vivo and in vitro.

Results

Compared to CD43^hi effector cells, CD43^lo effector CD8 T cells exhibited reduced cytolytic activity and lower granzyme B expression but showed increased survival. CD43^lo effector CD8 T cells also showed increased in vivo expansion after adoptive transfer and antigen challenge. The enhanced survival of CD43^lo CD8 T cells was also partly associated with CD62L expression.

Conclusion

We suggest that CD43 expression regulated by IL-12 priming plays an important role in differentiation and survival of CD8 T cells.

CD43 regulates Th2 differentiation and inflammation

CD43 is a highly glycosylated transmembrane protein that regulates T cell activation. CD43(-/-) T cells are hyperproliferative and the cytoplasmic tail of CD43 has been found to be sufficient to reconstitute wild-type proliferation levels, suggesting an intracellular mechanism. In this study, we report that upon TCR ligation CD43(-/-) T cells demonstrated no increase in tyrosine phosphorylation but a decreased calcium flux. Interestingly, CD43(-/-) T cells preferentially differentiated into Th2 cells in vitro, and CD43(-/-) T cells show increased GATA-3 translocation into the nucleus. In vivo, CD43(-/-) mice exhibited increased inflammation in two separate models of Th2-mediated allergic airway disease. In contrast, in Th1-mediated diabetes, nonobese diabetic CD43(-/-) mice did not significantly differ from wild-type mice in disease onset or progression. Th1-induced experimental autoimmune encephalomyelitis to MOG(35-55) was also normal in the CD43(-/-) mice. Nonetheless, the CD43(-/-) mice produced more IL-5 when restimulated with MOG(35-55) in vitro and demonstrated decreased delayed-type hypersensitivity responses. Together, these data demonstrate that although CD43(-/-) T cells preferentially differentiate into Th2 cells, this response is not sufficient to protect against Th1-mediated autoimmune responses.

Hepatocyte growth factor suppresses proinflammatory NFkappaB activation through GSK3beta inactivation in renal tubular epithelial cells

Activation of NFkappaB is a fundamental cellular event central to all inflammatory diseases. Hepatocyte growth factor (HGF) ameliorates both acute and chronic inflammation in a multitude of organ systems through modulating NFkappaB activity; nevertheless, the exact molecular mechanism remains uncertain. Here we report that HGF through inactivation of GSK3beta suppresses NFkappaB p65 phosphorylation specifically at position Ser-468. The Ser-468 of RelA/p65 situates in a GSK3beta consensus motif and could be directly phosphorylated by GSK3beta both in vivo and in vitro, signifying Ser-468 of RelA/p65 as a putative substrate for GSK3beta. In addition, the C terminus of RelA/p65 harbors a highly conserved domain homologue of the consensus docking sequence for GSK3beta. Moreover, this domain was required for efficient phosphorylation of Ser-468 and was indispensable for the physical interaction between RelA/p65 and GSK3beta. HGF substantially intercepted this interaction by inactivating GSK3beta. Functionally, phosphorylation of Ser-468 of RelA/p65 was required for the induced expression of a particular subset of proinflammatory NFkappaB-dependent genes. Diminished phosphorylation at Ser-468 by HGF resulted in a gene-specific inhibition of these genes' expression. The action of HGF on proinflammatory NFkappaB activation was consistently mimicked by a selective GSK3beta inhibitor or GSK3beta knockdown by RNA interference but largely abrogated in cells expressing the mutant uninhibitable GSK3beta. Collectively, our findings suggest that HGF has a potent suppressive effect on NFkappaB activation, which is mediated by GSK3beta, an important signaling transducer controlling RelA/p65 phosphorylation specificity and directing the transcription of selective proinflammatory cytokines implicated in inflammatory kidney disease.

CD43 signals induce Type One lineage commitment of human CD4+ T cells

Background

The activation and effector phenotype of T cells depend on the strength of the interaction of the TcR with its cognate antigen and additional signals provided by cytokines and by co-receptors. Lymphocytes sense both the presence of an antigen and also clues from antigen-presenting cells, which dictate the requisite response. CD43 is one of the most abundant molecules on the surface of T cells; it mediates its own signalling events and cooperates with those mediated by the T cell receptor in T cell priming. We have examined the role of CD43 signals on the effector phenotype of adult CD4⁺ and CD8⁺ human T cells, both alone and in the presence of signals from the TcR.

Results

CD43 signals direct the expression of IFNγ in human T cells. In freshly isolated CD4⁺ T cells, CD43 signals potentiated expression of the IFNγ gene induced by TcR activation; this was not seen in CD8⁺ T cells. In effector cells, CD43 signals alone induced the expression of the IFNγ gene in CD4⁺ T cells and to a lesser extent in CD8⁺ cells. The combined signals from CD43 and the TcR increased the transcription of the T-bet gene in CD4⁺ T cells and inhibited the transcription of the GATA-3 gene in both populations of T cells, thus predisposing CD4⁺ T cells to commitment to the T1 lineage. In support of this, CD43 signals induced a transient membrane expression of the high-affinity chains of the receptors for IL-12 and IFNγ in CD4⁺ T cells. CD43 and TcR signals also cooperated with those of IL-12 in the induction of IFNγ expression. Moreover, CD43 signals induced the co-clustering of IFNγR and the TcR and cooperated with TcR and IL-12 signals, triggering a co-capping of both receptors in CD4⁺ populations, a phenomenon that has been associated with a T1 commitment.

Conclusion

Our results suggest a key role for CD43 signals in the differentiation of human CD4⁺ T cells into a T1 pattern.

CD43 promotes cell growth and helps to evade FAS-mediated apoptosis in non-hematopoietic cancer cells lacking the tumor suppressors p53 or ARF

CD43 is a highly glycosylated transmembrane protein expressed on the surface of most hematopoietic cells. Expression of CD43 has also been demonstrated in many human tumor tissues, including colon adenomas and carcinomas, but not in normal colon epithelium. The potential contribution of CD43 to tumor development is still not understood. Here, we show that overexpression of CD43 increases cell growth and colony formation in mouse and human cells lacking expression of either p53 or ARF (alternative reading frame) tumor-suppressor proteins. In addition, CD43 overexpression also lowers the detection of the FAS death receptor on the cell surface of human cancer cells, and thereby helps to evade FAS-mediated apoptosis. However, when both p53 and ARF proteins are present, CD43 overexpression activates p53 and suppresses colony formation due to induction of apoptosis. These observations suggest CD43 as a potential contributor to tumor development and the functional ARF-p53 pathway is required for the elimination of cells with aberrant CD43 expression.

Nuclear accumulation of cRel following C-terminal phosphorylation by TBK1/IKK epsilon

The NF-kappaB transcription factors are key regulators of immunomodulatory, cell cycle, and developmental gene regulation. NF-kappaB activity is mainly regulated through the phosphorylation of IkappaB by the IkappaB kinase (IKK) complex IKKalphabetagamma, leading to proteasome-mediated degradation of IkappaB, nuclear translocation of NF-kappaB dimers, DNA binding, and gene induction. Additionally, direct posttranslational modifications of NF-kappaB p65 and cRel subunits involving C-terminal phosphorylation has been demonstrated. The noncanonical IKK-related homologs, TNFR-associated factor family member-associated NF-kappaB activator (TANK)-binding kinase (TBK)1 and IKKepsilon, are also thought to play a role in NF-kappaB regulation, but their functions remain unclear. TBK1 and IKKepsilon were recently described as essential regulators of IFN gene activation through direct phosphorylation of the IFN regulatory factor-3 and -7 transcription factors. In the present study, we sought to determine whether IKKepsilon and TBK1 could modulate cRel activity via phosphorylation. TBK1 and IKKepsilon directly phosphorylate the C-terminal domain of cRel in vitro and in vivo and regulate nuclear accumulation of cRel, independently of the classical IkappaB/IKK pathway. IkappaBalpha degradation is not affected, but rather IKKepsilon-mediated phosphorylation of cRel leads to dissociation of the IkappaBalpha-cRel complex. These results illustrate a previously unrecognized aspect of cRel regulation, controlled by direct IKKepsilon/TBK1 phosphorylation.

TCR-Dependent Cell Response Is Modulated by the Timing of CD43 Engagement

Binding of Ag by the Ag receptor in combination with other stimuli provided by costimulatory receptors triggers the expansion and differentiation of T lymphocytes. However, it is unclear whether the time when costimulatory molecules interact with their counterreceptors with regards to Ag recognition leads to different T cell responses. Provided that the coreceptor molecule CD43 is a very abundant molecule evenly distributed on the membrane of T cell surface protruding 45 nm from the cell, we hypothesized that CD43 is one of the first molecules that interacts with the APC and thus modulates TCR activation. We show that engaging CD43 before or simultaneously with the TCR inhibited Lck-Src homology 2 domain containing phosphatase-1 interaction, preventing the onset of a negative feedback loop on TCR signals, favoring high levels of IL-2, cell proliferation, and secretion of proinflammatory cytokines and chemokines. In contrast, the intracellular signals resulting of engaging the TCR before CD43 were insufficient to induce IL-2 production and cell proliferation. Interestingly, when stimulated through the TCR and CD28, cells proliferated vigorously, independent of the order with which molecules were engaged. These results indicate that CD43 induces a signaling cascade that prolongs the duration of TCR signaling and support the temporal summation model for T cell activation. In addition to the strength and duration of intracellular signals, our data underscore temporality with which certain molecules are engaged as yet another mechanism to fine tune T cell signal quality, and ultimately immune function.

Endothelial cell expression of galectin-1 induced by prostate cancer cells inhibits T-cell transendothelial migration

A critical control point in the immune response to tumors or to pathogens is the egress of lymphocytes from blood into damaged or infected tissue. While several specific endothelial cell proteins promote lymphocyte adhesion to and migration across endothelium, little is known about endothelial cell surface proteins that negatively regulate transendothelial migration of lymphocytes. Galectin-1 is a mammalian lectin expressed by a variety of cell types, including endothelial cells, that has pleiotropic anti-inflammatory effects. Galectin-1 is known to alter T-cell cytokine production and to trigger T-cell death. We now demonstrate that galectin-1 inhibits T-cell migration across endothelial cells, identifying a novel anti-inflammatory effect of galectin-1. We observed reduced T-cell migration across endothelial cells induced to increase galectin-1 expression by exposure to prostate cancer cell conditioned medium, compared to T-cell migration across control-treated endothelial cells, and the inhibitory effect of galectin-1 on T-cell migration was reversed by specific antiserum. Decreased T-cell migration was not due to decreased adhesion to galectin-1 expressing endothelial cells, nor to death of T cells, as T cells lacking core 2 O-glycans and thus resistant to galectin-1 death displayed reduced migration across endothelial cells. Galectin-1 on the surface of extracellular matrix also reduced the ability of T cells to migrate through the matrix. T cells bound to galectin-1-coated matrix demonstrated enhanced clustering of CD43, including at the T-cell:matrix interface, compared to CD43 on T cells bound to matrix in the absence of galectin-1. As translocation of CD43 to the trailing edge is essential for polarized T-cell migration, these data indicate that galectin-1-mediated clustering of CD43 contributes to the inhibitory effect on T-cell migration. Inhibition of T-cell migration is a novel anti-inflammatory activity of galectin-1.

Upregulation of ICOS on CD43+ CD4+ murine small intestinal intraepithelial lymphocytes during acute reovirus infection

Murine intestinal intraepithelial lymphocytes (IELs) can be classified according to expression of a CD43 glycoform recognized by the S7 monoclonal antibody. In this study, we examined the response of S7+ and S7- IELs in mice during acute reovirus serotype 3 (Dearing strain) infection, which was confirmed by virus-specific real-time PCR. In vivo proliferation increased significantly for both S7- and S7+ IELs on day 4 post-infection as determined by BrdU incorporation; however, expression of the inducible costimulatory (ICOS) molecule, which peaked on day 7 post-infection, was upregulated on S7+ CD4+ T cells, most of which were CD4+8- IELs. In vitro ICOS stimulation by syngeneic peritoneal macrophages induced IFN-gamma secretion from IELs from day 7 infected mice, and was suppressed by treatment with anti-ICOS mAb. Additionally, IFN-gamma mRNA increased in CD4+ IELs on day 6 post-infection. These findings indicate that S7- and S7+ IELs are differentially mobilized during the immune response to reovirus infection; that the regulated expression of ICOS is associated with S7+ IELs; and that stimulation of IELs through ICOS enhances IFN-gamma synthesis during infection.

Inducible phosphorylation of NF-kappa B p65 at serine 468 by T cell costimulation is mediated by IKK epsilon

Here we identify IKKepsilon as a novel NF-kappaB p65 kinase that mediates inducible phosphorylation of Ser468 and Ser536 in response to T cell costimulation. In addition, the kinase activity of IKKepsilon contributes to the control of p65 nuclear uptake. Serines 468 and 536 are evolutionarily conserved, and the surrounding amino acids display sequence homology. Down-regulation of IKKepsilon levels by small interfering RNA does not affect inducible phosphorylation of Ser536 but largely prevents Ser468 phosphorylation induced by T cell costimulation. Ser536-phosphorylated p65 is found predominantly in the cytosol. In contrast, the Ser468 phosphorylated form of this transcription factor occurs mainly in the nucleus, suggesting a function for transactivation. Reconstitution of p65-/- cells with either wild type p65 or point-mutated p65 variants showed that inducible phosphorylation of Ser468 serves to enhance p65-dependent transactivation. These results also provide a mechanistic link that helps to explain the relevance of IKKepsilon for the expression of a subset of NF-kappaB target genes without affecting cytosolic IkappaBalpha degradation.

Phosphorylation of NF-kappaB and IkappaB proteins: implications in cancer and inflammation

Nuclear factor-kappaB (NF-kappaB) is a transcription factor that has crucial roles in inflammation, immunity, cell proliferation and apoptosis. Activation of NF-kappaB mainly occurs via IkappaB kinase (IKK)-mediated phosphorylation of inhibitory molecules, including IkappaBalpha. Optimal induction of NF-kappaB target genes also requires phosphorylation of NF-kappaB proteins, such as p65, within their transactivation domain by a variety of kinases in response to distinct stimuli. Whether, and how, phosphorylation modulates the function of other NF-kappaB and IkappaB proteins, such as B-cell lymphoma 3, remains unclear. The identification and characterization of all the kinases known to phosphorylate NF-kappaB and IkappaB proteins are described here. Because deregulation of NF-kappaB and IkappaB phosphorylations is a hallmark of chronic inflammatory diseases and cancer, newly designed drugs targeting these constitutively activated signalling pathways represent promising therapeutic tools.