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Suppresses Activation of Nuclear Transcription Factors NF-
B and Activator Protein 1 and Potentiates TNF-Induced Apoptosis1
Cytokine Research Laboratory, Department of Bioimmunotherapy, M.D. Anderson Cancer Center, University of Texas, Houston, TX 77030
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Abstract |
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potentiates the apoptotic
effects of TNF through a mechanism that is not understood. Because the
nuclear transcription factors NF-
B and AP-1 have recently been
reported to mediate anti-apoptosis and cell survival, we
hypothesized that IFN- potentiates the cytotoxic effects of TNF by
suppressing TNF-induced activation of NF-B and AP-1. We tested this
hypothesis by pretreating human Jurkat T cells with IFN-, which
blocked TNF-induced activation of NF-B and AP-1 in a time- and
dose-dependent manner as determined by EMSA. IFN- blocked
TNF-induced phosphorylation and degradation of the inhibitor subunit of
NF-B, and suppressed NF-B and AP-1 activation induced by various
other inflammatory stimuli. NF-B-dependent reporter gene expression
activated by TNF, TNFR1, TNF receptor-associated factor 2, and
NF-B-inducing kinase was also abrogated by IFN- pretreatment. The
suppression of NF-B and AP-1 correlated with the potentiation of
TNF-induced cytotoxicity and caspase activation. Overall our results
suggest that IFN- potentiates the apoptotic effects of TNF possibly
by suppressing NF-B and AP-1 activation. |
Introduction |
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TopAbstractIntroductionMaterials and MethodsResults and DiscussionReferences |
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(1, 2, 3, 4, 5, 6, 7). The mechanism by which
these two cytokines synergize is not understood. Initially, it was
thought that up-regulation of TNF receptors by IFN accounted for the
synergism (8, 9), but subsequent experiments revealed that
the induction of TNF receptors does not correlate with their
synergistic cytotoxic response (10, 11). Recently, the
nuclear transcription factor NF-B has been reported to be an
anti-apoptotic factor that plays a major role in cell survival
during apoptosis induced by cytokines and various chemotherapeutic
agents (12, 13).
Among the cytokines, TNF is also the most potent activator of NF-B
(14). The transcription factor AP-1 likewise plays an
important role in proliferation of most cells and is also activated by
TNF (15). TNF activates NF-B and AP-1 through
sequential interaction of the TNF receptor TNFR1 with TNF
receptor-associated death domain
(TRADD)3 and TNF
receptor-associated factor (TRAF)2 (16, 17). Further
interaction of TRAF2 with NF-B-inducing kinase (NIK) and IB
kinase (IKK)-ß results in phosphorylation of the inhibitory subunit
of NF-B (IB) and NF-B activation, whereas activation of
c-jun N-terminal protein kinase by TRAF2 leads to activation of AP-1
(16, 17). Thus both NF-B and AP-1, which play a role in
cell survival, are activated by TNF through a pathway involving
overlapping and nonoverlapping steps.
Based on these observations, we hypothesized that the synergism between
TNF and IFN involves down-regulation of TNF-induced cell survival
mechanisms (i.e., suppression of activation of NF-B and AP-1 by
IFN). In the present report, we demonstrate that IFN pretreatment
abolishes TNF-induced activation of NF-B and AP-1. This correlated
with suppression of both the phosphorylation and degradation of
IB, an inhibitor of NF-B, and synergistic potentiation of
cytotoxic response and caspase-induced substrate cleavage.
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Materials and Methods |
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TopAbstractIntroductionMaterials and MethodsResults and DiscussionReferences |
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Clinical grade IFN- (Roferon A) was kindly supplied by Dr.
Moshe Talpaz of the M.D. Anderson Cancer Center (Houston, TX).
Bacteria-derived recombinant human TNF, purified to homogeneity with a
specific activity of 5 x 107 U/mg, was
kindly provided by Genentech (South San Francisco, CA). Abs against
IB and p65 were obtained from Santa Cruz Biotechnology (Santa
Cruz, CA). Poly (ADP ribose) polymerase (PARP) Ab was purchased from
PharMingen (San Diego, CA). Phospho-IB
(Ser32) Ab was purchased from New England Biolabs
(Beverly, MA). Expression plasmids encoding FLAG-tagged NIK
(18) were kindly provided by Dr. D. Wallach (Weizmann
Institute of Science, Rehovot, Israel). The expression plasmid encoding
myc-tagged TRAF2, NIK, p65, and dominant-negative IB have been
previously described (19).
Cell lines
In this study, we used Jurkat (T-cells) obtained from American Type Culture Collection (Manassas, VA). Cells were cultured in RPMI 1640 medium supplemented with 10% FBS, 100 U/ml penicillin, and 100 µg/ml streptomycin.
NF-B and AP-1 activation assays
To measure NF-B and AP-1 activation, nuclear extracts from
treated cells were subjected to EMSA essentially as described from our
laboratory (20).
NF-B-dependent reporter gene transcription
The effect of IFN- on TNF-, TRAF-2-, NIK-, and p65
(transactivation subunit of NF-B)-induced NF-B-dependent reporter
gene transcription was measured as previously described
(19). Human Jurkat T cells were transiently transfected by
the calcium phosphate method with 1 ml medium containing plasmid DNAs
for TRAF2, NIK, or p65 (1 µg each) along with 0.5 µg NF-B
promoter DNA linked to the heat-stable secretory alkaline phosphatase
(SEAP) gene. The total final amount of DNA was maintained at 3 µg by
the addition of the control plasmid pCMVFLAG1 DNA. Twenty-four hours
after transfection, the conditioned medium was removed and assayed for
SEAP activity essentially as described by the manufacturer (Clontech,
Palo Alto, CA).
In brief, 25 µl medium was mixed with 30 µl of 5x buffer (500 mM
Tris (pH 9) and 0.5% BSA) in a total volume of 100 µl in a 96-well
plate and incubated at 65°C for 30 min. The plate was chilled on ice
for 2 min. Then 50 µl of 1 mM 4-methylumbelliferyl phosphate was
added to each well and incubated at 37°C for 2 h. The activity
of SEAP was assayed on a 96-well fluorescent plate reader (Fluoroscan
II, Lab Systems, Needham Heights, MA) with excitation set at 360 nm and
emission at 460 nm. The average number (± SD) of relative fluorescent
light units for each transfection was then determined and reported as
fold activation with respect to control vector-transfected cells. The
NF-B SEAP reporter used in these assays was shown to be activated by
TNF and by overexpression of TNFR. The specificity was established of
this reporter system by the fact that TNF-induced NF-B SEAP activity
was inhibited by overexpression of either an IkBa mutant lacking
Ser32/36, a kinase-inactive NIK, or a
dominant-negative TRAF2 mutant (19).
IB phosphorylation
To determine the effect of IFN- on IB phosphorylation,
cytoplasmic extracts were prepared from cells (2 x
106 cells/ml) treated with 100 U/ml IFN- for
72 h and then treated with 0.1 nM TNF for different times. The
extracts were then resolved on 10% SDS-PAGE and analyzed by Western
blot using Abs against either IB or phosphorylated IB
(21). After electrophoresis, the proteins were detected by
chemiluminescence (Amersham, Arlington Heights, IL).
IKK assay
The IKK assay was performed by a method described
(22). Briefly, IKK signalosomes were precipitated by
treating 300 µg cytoplasmic extracts with 1 µg anti-IKK Ab
overnight at 4°C (Imgenex, San Diego, CA; catalog no. IMG-136),
followed by treatment with 20 µl protein A/G-Sepharose (Pierce,
Rockford, IL). After 2 h, the beads were washed three times with
lysis buffer and three times with the kinase assay buffer and then
resuspended in 20 µl of kinase assay mixture containing 50 mM HEPES
(pH 7.4), 20 mM MgCl2, 2 mM DTT, 20 µCi 
-ATP, 10 µM
unlabeled ATP, and 2 µg of substrate GST-IB (amino acid
residues 1–54). After incubation at 30°C for 30 min, reaction was
terminated by boiling with 5 µl of 5x SDS sample buffer for 5 min.
Finally, the protein was resolved on 10% polyacrylamide gel under
reducing conditions, the gel was dried, and the radioactive bands were
visualized by PhosphorImager. To determine the total amounts of IKK
and IKKß in each sample, 60 µg of the cytoplasmic protein were
resolved on 7.5% acrylamide gels, electrotransferred to a
nitrocellulose membrane, blocked on the membrane with 5% nonfat milk
protein for 1 h, and then incubated with either anti-IKK or
anti-IKKß (IMG-129) Abs (at 1:500 dilution) for 1 h. The
membrane was then washed and reacted with HRP-conjugated
secondary anti-mouse IgG Ab, and finally detected by
chemiluminescence (Amersham Pharmacia Biotechnology, Arlington
Heights, IL).
Cytotoxicity assay
The TNF-induced cytotoxicity was measured by the MTT assay (21). Briefly, cells (5,000 cells/well) were incubated in the presence or absence of the indicated test sample in a final volume of 0.1 ml for 72 h at 37°C. Thereafter, cell viability was examined by the MTT method. The ODs were measured at 590 nm using the extraction buffer as a blank.
Immunoblot analysis of PARP degradation
TNF-induced apoptosis was examined by proteolytic cleavage of PARP (21). Apoptosis was represented by the cleavage of 116-kDa PARP into an 85-kDa product.
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Results and Discussion |
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TopAbstractIntroductionMaterials and MethodsResults and DiscussionReferences |
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on TNF-induced
cellular responses. For most studies, Jurkat T cells were used because
these cells express both types of TNF receptor, and cellular responses
to TNF are well characterized in our laboratory (23). For
most studies IFN- was used; similar results were obtained with
IFN-ß as well.
IFN- suppresses TNF-induced NF-B activation
Jurkat cells were treated with 1, 10, and 100 U/ml of IFN- for
24, 48, and 72 h, and then activated for NF-B by 0.1 nM TNF for
30 min and examined for NF-B activation by EMSA. As shown in Fig. 1
, TNF activated NF-B by 5-fold, and
IFN- pretreatment diminished TNF-induced NF-B activation in a
time- and dose-dependent manner. Maximum suppression was observed when
cells were treated with 100 U/ml IFN- for 72 h. IFN- alone
did not activate NF-B (Fig. 1). We also noted suppression of
TNF-induced NF-B activation by IFN-ß (data not shown), which is
not too surprising considering that the two IFNs share receptor
subunits (24).
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B that is inhibited by IFN- consists of p50 and
p65 subunits
Various combinations of Rel/NF-B proteins can constitute an
active NF-B heterodimer that binds to specific sequences in DNA
(14). To show that the retarded band visualized by EMSA in
TNF-treated cells was indeed NF-B, we incubated nuclear extracts
from TNF-activated cells with Ab to either the p50 (NF-B1) or p65
(Rel A) subunits and then conducted EMSA. Abs to either subunit of
NF-B shifted the band to a higher m.w. (Fig. 2A), thus suggesting that the
TNF-activated complex consisted of p50 and p65 subunits. Neither
preimmune serum nor such irrelevant Abs as anti-cRel or
anti-cyclin D1 affected the mobility of NF-B. Excess unlabeled
NF-B (100-fold) caused complete disappearance of the band but mutant
oligo did not, indicating the specificity of NF-B.
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B activation. Whether IFN- suppresses TNF-induced
NF-B activation through suppression of synthesis of NF-B
proteins, was examined. As shown in Fig. 2
B, treatment of
cells with different concentrations of IFN- for 72 h had no
effect on the levels of p50, p65, or IB. These results suggest
that IFN- modulates TNF signaling leading to NF-B activation.
However, whether protein synthesis is required for modulation of TNF
signaling by IFN- could not be ascertained from these
experiments.
Inhibition of NF-B activation by IFN- is not cell type
specific
All of the effects of IFN- described in this report were
observed in human Jurkat T cells. Therefore, we also studied whether
IFN- could also block TNF-induced NF-B activation in myeloid
(U-937) cells, epithelial (HeLa) cells, and embryonic kidney (293) and
glioma (H4) cells. In these experiments (Fig. 3), IFN- inhibited TNF-induced NF-B
activation in all cell types, suggesting that this effect is not
restricted to T cells.
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inhibits TNF-dependent phosphorylation and degradation of
IB
To determine whether inhibition of TNF-induced NF-B activation
was due to inhibition of IB degradation, cells were pretreated
with 100 U/ml IFN- for 72 h, exposed to 0.1 nM TNF for
different times, and then examined for NF-B in the nucleus by EMSA
and for IB in the cytoplasm by Western blot. As shown in Fig. 4A, TNF activated NF-B in
the control cells in a time-dependent manner but had no effect in
IFN--pretreated cells. TNF induced IB degradation in control
cells to a maximum reached at 15 min, but in IFN--treated cells
TNF-induced IB degradation was completely suppressed (Fig. 4B). We also examined the hyperphosphorylated form of
IB by Western blot using Abs that detect only the
serine-phosphorylated form of IB. The results in Fig. 4C clearly show that TNF induced the phosphorylation of
IB which could be seen as early as 5 min, and IFN- completely
suppressed IB phosphorylation. Because TNF-induced
phosphorylation of IB is mediated through IKK-ß
(25), these results suggest that IFN- must inhibit
IKK-ß activation. Therefore, we investigated the effect of IFN- on
TNF-induced IKK-ß activation. As shown in Fig. 4D
(upper panel), in the immunocomplex kinase assays
TNF-activated IKK-ß and IFN- treatment completely suppressed the
activation. Under these conditions, IFN- had no effect on the
IKK- and IKK-ß protein levels (middle and lower
panels).
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represses TNF-induced NF-B-dependent reporter gene
expression
TNF-induced NF-B activation is mediated through sequential
interaction of the TNF receptor TNFR1 with TRADD, TRAF2, NIK, and
IKK-ß, resulting in phosphorylation of IB (16, 17). To delineate the site of action of IFN- in the
TNF-signaling pathway leading to NF-B activation, cells were
transfected with TNFR1, TRAF2, NIK, and p65 plasmids, and then
NF-B-dependent SEAP expression was monitored in IFN--untreated
and -treated cells. As shown in Fig. 5, TNFR1, TRAF2, NIK, and p65 plasmids induced gene expression, and
IFN- suppressed TNFR1-, TRAF2-, and NIK-induced expression but had
little effect on p65-induced NF-B reporter expression. Receptor
activator of NF-B, another NF-B-inducing receptor that is a
member of the TNFR1 family (19), was minimally affected by
IFN-, indicating the specificity. The lack of effect of IFN- on
the NF-B activation induced by p65 and receptor activator of NF-B
plasmids also indicates that IFN- treatment does not affect the
transfection efficiency. Specificity of the assay results are also
indicated by suppression of TNF-induced NF-B reporter activity by
the dominant-negative IB plasmid. Thus IFN- must act at a step
downstream from NIK. Because NIK is known to activate IKK-ß, which in
turn phosphorylates IB, it appears that IFN- blocked the
activity of IKK-ß, a kinase that phosphorylates IB directly.
This is in agreement with our results indicated in the previous section
that IFN- inhibits TNF-induced IKK-ß activation
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blocks LPS- and ceramide-mediated activation of NF-B
NF-B is also activated by a wide variety of other agents
besides TNF, including phorbol ester, LPS, okadaic acid, ceramide, and
HIV-tat. However, the signal transduction pathway induced by various
activators may differ (26, 27). Therefore, we examined the
effect of IFN- on the activation of NF-B by these various agents.
The results shown in Fig. 6 indicate that
IFN- suppressed the activation of NF-B induced by LPS and
ceramide but had minimal effect on NF-B activation induced by
H2O2, okadaic acid, PMA, or
HIV-tat. These results suggest that IFN- may act at a step where
TNF, ceramide, and LPS converge in the signal transduction pathway
leading to NF-B activation.
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inhibits TNF-induced AP-1 activation
TNF is also one of the most potent activators of AP-1
(15). To determine the effect of IFN- on TNF-induced
AP-1 activation, Jurkat cells were treated with 1, 10, and 100 U/ml of
IFN- for 24, 48, and 72 h and then activated for AP-1 by 0.1 nM
TNF for 30 min and examined for AP-1 activation by EMSA. As shown in
Fig. 7, A–C, TNF
activated AP-1 by 4-fold and IFN- pretreatment abolished TNF-induced
AP-1 activation in a time- and dose-dependent manner. Maximum
suppression was observed when cells were treated with 100 U/ml IFN-
for 48 h. IFN- alone did not activate AP-1 (Fig. 7C). We also noted suppression of TNF-induced AP-1
activation by IFN-ß (data not shown). As indicated by the supershift
analysis, TNF-induced AP-1 consisted of Fos and Jun subunits (Fig. 7D). Nonspecific Abs had no effect on the supershift.
Formation of the AP-1 band could be prevented by unlabeled
oligonucleotide (Fig. 7D).
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on the activation of AP-1
by these various agents. The results shown in Fig. 5E
indicate that IFN- suppressed the activation of AP-1 induced by LPS
and H2O2 but had minimal
effect on AP-1 activation induced by ceramide, okadaic acid, PMA, or
HIV-tat. These results suggest that IFN- may act at a step where
TNF, H2O2, and LPS converge
in the signal transduction pathway leading to AP-1 activation. Although
H2O2-induced NF-B was
unaffected by IFN-,
H2O2-induced AP-1 was
completely suppressed, suggesting a difference in the mechanism of
activation of these two transcription factors. This is in agreement
with the results of Meyer et al. (28).
IFN- potentiates TNF-induced cytotoxicity and caspase activation
Among the cytokines, TNF is one of the most potent inducers of
apoptosis (for references see Ref. 29). Whether IFN-
modulates TNF-induced apoptosis was also investigated in Jurkat cells.
For this, cells were treated with various concentrations of IFN- for
72 h, then treated with 10 pM TNF for an additional 72 h, and
then examined for cytotoxicity by the MTT method (Fig. 8A). Both IFN- and TNF by
themselves had minimal effects on the viability of Jurkat cells.
However, preexposure to IFN- sensitized the cells to TNF-induced
cytotoxicity in a dose-dependent manner.
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on
TNF-induced caspase activation. Activated caspase-2, -3, and -7 are
known to cleave PARP protein. As shown in Fig. 8B, in
untreated cells 0.1 nM TNF induced a partial cleavage of PARP, but in
IFN--pretreated cells TNF induced complete cleavage of PARP
substrate. These results thus suggest that IFN- pretreatment also
sensitizes the cells to TNF-induced caspase activation.
To determine whether IFN- also affected TNF receptors in Jurkat
cells, we examined the effect of IFN- on TNF receptors by
receptor-binding assays. TNF bound to Jurkat cells, and this binding
was completely unaffected by pretreatment of cells with IFN- for
72 h (data not shown). These results suggest that the suppression
of NF-B and AP-1 by IFN- were not due to down-regulation of TNF
receptors.
Our results clearly demonstrate that IFN- can down-regulate
TNF-induced NF-B and AP-1, which most likely contributes to the
synergistic apoptotic effects of the two cytokines. The suppression of
NF-B by IFN- is mediated through suppression of IB
phosphorylation and degradation. Also we show that IFN- acts at a
step downstream from NIK. Because only IKK-ß mediates TNF-induced
phosphorylation of IB at positions 32 and 36, we suggest that
IFN- may suppress NF-B activation through suppression of
IKK-ß.
Our results indicate that IFN- also blocked TNF-induced AP-1
activation. TRAF2, which is known to bind to TNF receptor through
TRADD, is also required for AP-1 (16, 17). The suppression
of TRAF2 activity may explain how IFN- inhibits AP-1 activation. Are
NF-B and AP-1 suppressed by IFN- by a similar mechanism? Recent
studies from our laboratory showed that inducing overexpression of
cells with either superoxide dismutase (23) or
-glutamylcysteine synthetase, a rate-limiting enzyme in the
glutathione biosynthesis pathway (30), blocked both
NF-B and AP-1 activation induced by TNF, indicating a similar
mechanism of activation of both transcription factors. Though these
results also imply that IFN- may suppress these factors by
regulating the redox status of the cells, it is unlikely because
TNF-induced cytotoxicity, which also requires reactive oxygen
intermediates (31), was potentiated by IFN- through
suppression of reactive oxygen intermediates.
We found that IFN- blocked NF-B-dependent reporter gene
expression. Several genes that are involved in various diseases are
regulated by NF-B. These include inflammatory cytokines,
cyclooxygenase-2, metalloproteinases, urinary plasminogen activator, NO
synthase, and cell surface adhesion molecules (32, 33, 34, 35, 36, 37).
Thus it is possible that IFN- mediates its immunosuppressive effects
through suppression of NF-B-regulated genes. Indeed the suppression
by IFN- of cyclooxygenase-2, NO synthase, and inflammatory cytokines
has been reported (38, 39, 40, 41, 42). Because NF-B-regulated gene
products have also been implicated in tumorigenesis, IFN- may prove
useful in suppressing tumorigenesis in vitro (43) and in
vivo (44). Our results also provide the basis for the
synergistic apoptotic effects of TNF and IFN-.
Constitutively active NF-B has been identified in a variety of
tumors, including Hodgkin disease; T cell lymphoma; breast, ovarian,
and prostate carcinomas; and a variety of others tumors
(45, 46, 47, 48). The active form of NF-B is required for
proliferation of these tumors (46, 47), and its
suppression inhibits the growth. Thus it is possible that suppression
of NF-B and also AP-1 in these tumors by IFN- may prove useful in
inhibition of their proliferation.
In the murine system, IFN- is known to induce a protein p202 which
blocks phorbol ester-induced activation of NF-B and AP-1 reporter
gene expression (49). Because p202 did not decrease the
DNA binding of NF-B as detected by EMSA (49), it is
unlikely that in our system human IFN- is suppressing TNF-induced
NF-B activation through p202 protein. In addition phorbol
ester-induced NF-B activation in our system was unaffected by
pretreatment of cells with IFN-. Besides, the role of p202-like
protein in human system has not been reported.
NF-B has been proposed as a reasonable target for new anticancer
drugs (50). Although adenoviral IB, an NF-B
inhibitor, has been used for the treatment of arthritis and
tumorigenesis (13, 51), and our data suggest its
potential. We believe that the use of IFN- to suppress NF-B
activation is preferable. IFN- has proven to be safe for human
administration and has been approved as a drug for treatment of
cancers. In addition, unlike problems associated with gene delivery
(which would be required if IB were used), there are no real
delivery problems associated with IFN-.
Overall our results indicate that suppressive effects of IFN- on
NF-B and AP-1 activation may have therapeutic effects in diseases in
which TNF plays a major role. We have shown that this potential lies in
IFN- ability to modulate TNF activation of various transcription
factors.
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Footnotes |
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2 Address correspondence and reprint requests to Dr. Bharat B. Aggarwal, University of Texas M.D. Anderson Cancer Center, Department of Bioimmunotherapy, 1515 Holcombe Boulevard, Box 143, Houston, TX 77030-4095.
3 Abbreviations used in this paper: TRADD, TNF receptor-associated death domain; IB, inhibitory subunit of NF-B; TRAF, TNF receptor-associated factor; NIK, NF-B-inducing kinase; IKK, IB kinase; PARP; poly (ADP ribose) polymerase; SEAP, secretory alkaline phosphatase.
Received for publication February 17, 2000. Accepted for publication August 3, 2000.
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 A. B. Kunnumakkara, A. S. Nair, K. S. Ahn, M. K. Pandey, Z. Yi, M. Liu, and B. B. Aggarwal Gossypin, a pentahydroxy glucosyl flavone, inhibits the transforming growth factor beta-activated kinase-1-mediated NF-{kappa}B activation pathway, leading to potentiation of apoptosis, suppression of invasion, and abrogation of osteoclastogenesis Blood, June 15, 2007; 109(12): 5112 - 5121. [Abstract] [Full Text] [PDF]
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 S. Keslacy, O. Tliba, H. Baidouri, and Y. Amrani Inhibition of Tumor Necrosis Factor-{alpha}-Inducible Inflammatory Genes by Interferon-{gamma} Is Associated with Altered Nuclear Factor-{kappa}B Transactivation and Enhanced Histone Deacetylase Activity Mol. Pharmacol., February 1, 2007; 71(2): 609 - 618. [Abstract] [Full Text] [PDF]
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A. S. Nair, S. Shishodia, K. S. Ahn, A. B. Kunnumakkara, G. Sethi, and B. B. Aggarwal Deguelin, an Akt Inhibitor, Suppresses I{kappa}B{alpha} Kinase Activation Leading to Suppression of NF-{kappa}B-Regulated Gene Expression, Potentiation of Apoptosis, and Inhibition of Cellular Invasion J. Immunol., October 15, 2006; 177(8): 5612 - 5622. [Abstract] [Full Text] [PDF]
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Y. Osawa, S. Iho, R. Takauji, H. Takatsuka, S. Yamamoto, T. Takahashi, S. Horiguchi, Y. Urasaki, T. Matsuki, and S. Fujieda Collaborative Action of NF-{kappa}B and p38 MAPK Is Involved in CpG DNA-Induced IFN-{alpha} and Chemokine Production in Human Plasmacytoid Dendritic Cells J. Immunol., October 1, 2006; 177(7): 4841 - 4852. [Abstract] [Full Text] [PDF]
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 H. Ichikawa, M. S. Nair, Y. Takada, D.B. A. Sheeja, M.A. S. Kumar, O. V. Oommen, and B. B. Aggarwal Isodeoxyelephantopin, a Novel Sesquiterpene Lactone, Potentiates Apoptosis, Inhibits Invasion, and Abolishes Osteoclastogenesis through Suppression of Nuclear Factor-{kappa}B (NF-{kappa}B) Activation and NF-{kappa}B-Regulated Gene Expression. Clin. Cancer Res., October 1, 2006; 12(19): 5910 - 5918. [Abstract] [Full Text] [PDF]
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 M. N. Sharif, D. Sosic, C. V. Rothlin, E. Kelly, G. Lemke, E. N. Olson, and L. B. Ivashkiv Twist mediates suppression of inflammation by type I IFNs and Axl J. Exp. Med., August 7, 2006; 203(8): 1891 - 1901. [Abstract] [Full Text] [PDF]
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 H. Ichikawa, Y. Takada, S. Shishodia, B. Jayaprakasam, M. G. Nair, and B. B. Aggarwal Withanolides potentiate apoptosis, inhibit invasion, and abolish osteoclastogenesis through suppression of nuclear factor-{kappa}B (NF-{kappa}B) activation and NF-{kappa}B-regulated gene expression. Mol. Cancer Ther., June 1, 2006; 5(6): 1434 - 1445. [Abstract] [Full Text] [PDF]
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 H. Ichikawa, A. Murakami, and B. B. Aggarwal 1'-Acetoxychavicol Acetate Inhibits RANKL-Induced Osteoclastic Differentiation of RAW 264.7 Monocytic Cells by Suppressing Nuclear Factor-{kappa}B Activation Mol. Cancer Res., April 1, 2006; 4(4): 275 - 281. [Abstract] [Full Text] [PDF]
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H. Ichikawa and B. B. Aggarwal Guggulsterone Inhibits Osteoclastogenesis Induced by Receptor Activator of Nuclear Factor-{kappa}B Ligand and by Tumor Cells by Suppressing Nuclear Factor-{kappa}B Activation Clin. Cancer Res., January 15, 2006; 12(2): 662 - 668. [Abstract] [Full Text] [PDF]
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S. Aggarwal, H. Ichikawa, Y. Takada, S. K. Sandur, S. Shishodia, and B. B. Aggarwal Curcumin (Diferuloylmethane) Down-Regulates Expression of Cell Proliferation and Antiapoptotic and Metastatic Gene Products through Suppression of I{kappa}B{alpha} Kinase and Akt Activation Mol. Pharmacol., January 1, 2006; 69(1): 195 - 206. [Abstract] [Full Text] [PDF]
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 A Suarez, P Lopez, L Mozo, and C Gutierrez Differential effect of IL10 and TNF{alpha} genotypes on determining susceptibility to discoid and systemic lupus erythematosus Ann Rheum Dis, November 1, 2005; 64(11): 1605 - 1610. [Abstract] [Full Text] [PDF]
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H. Ichikawa, Y. Takada, A. Murakami, and B. B. Aggarwal Identification of a Novel Blocker of I{kappa}B{alpha} Kinase That Enhances Cellular Apoptosis and Inhibits Cellular Invasion through Suppression of NF-{kappa}B-Regulated Gene Products J. Immunol., June 1, 2005; 174(11): 7383 - 7392. [Abstract] [Full Text] [PDF]
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S. Shishodia and B. B. Aggarwal Guggulsterone Inhibits NF-{kappa}B and I{kappa}B{alpha} Kinase Activation, Suppresses Expression of Anti-apoptotic Gene Products, and Enhances Apoptosis J. Biol. Chem., November 5, 2004; 279(45): 47148 - 47158. [Abstract] [Full Text] [PDF]
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 P. Sagoo, G. Chan, D. F. P. Larkin, and A. J. T. George Inflammatory Cytokines Induce Apoptosis of Corneal Endothelium through Nitric Oxide Invest. Ophthalmol. Vis. Sci., November 1, 2004; 45(11): 3964 - 3973. [Abstract] [Full Text] [PDF]
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S. Aggarwal, Y. Takada, A. M. Mhashilkar, K. Sieger, S. Chada, and B. B. Aggarwal Melanoma Differentiation-Associated Gene-7/IL-24 Gene Enhances NF-{kappa}B Activation and Suppresses Apoptosis Induced by TNF J. Immunol., October 1, 2004; 173(7): 4368 - 4376. [Abstract] [Full Text] [PDF]
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Y. Takada, X. Fang, Md. S. Jamaluddin, D. D. Boyd, and B. B. Aggarwal Genetic Deletion of Glycogen Synthase Kinase-3{beta} Abrogates Activation of I{kappa}B{alpha} Kinase, JNK, Akt, and p44/p42 MAPK but Potentiates Apoptosis Induced by Tumor Necrosis Factor J. Biol. Chem., September 17, 2004; 279(38): 39541 - 39554. [Abstract] [Full Text] [PDF]
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S. Shishodia, D. Koul, and B. B. Aggarwal Cyclooxygenase (COX)-2 Inhibitor Celecoxib Abrogates TNF-Induced NF-{kappa}B Activation through Inhibition of Activation of I{kappa}B{alpha} Kinase and Akt in Human Non-Small Cell Lung Carcinoma: Correlation with Suppression of COX-2 Synthesis J. Immunol., August 1, 2004; 173(3): 2011 - 2022. [Abstract] [Full Text] [PDF]
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 S. Shishodia and B. B. Aggarwal Cyclooxygenase (COX)-2 Inhibitor Celecoxib Abrogates Activation of Cigarette Smoke-Induced Nuclear Factor (NF)-{kappa}B by Suppressing Activation of I-{kappa}B {alpha} Kinase in Human Non-Small Cell Lung Carcinoma: Correlation with Suppression of Cyclin D1, COX-2, and Matrix Metalloproteinase-9 Cancer Res., July 15, 2004; 64(14): 5004 - 5012. [Abstract] [Full Text] [PDF]
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Y. Takada and B. B. Aggarwal TNF Activates Syk Protein Tyrosine Kinase Leading to TNF-Induced MAPK Activation, NF-{kappa}B Activation, and Apoptosis J. Immunol., July 15, 2004; 173(2): 1066 - 1077. [Abstract] [Full Text] [PDF]
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 T. Y. Ma, G. K. Iwamoto, N. T. Hoa, V. Akotia, A. Pedram, M. A. Boivin, and H. M. Said TNF-{alpha}-induced increase in intestinal epithelial tight junction permeability requires NF-{kappa}B activation Am J Physiol Gastrointest Liver Physiol, March 1, 2004; 286(3): G367 - G376. [Abstract] [Full Text] [PDF]
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Y. Takada and B. B. Aggarwal Flavopiridol Inhibits NF-{kappa}B Activation Induced by Various Carcinogens and Inflammatory Agents through Inhibition of I{kappa}B{alpha} Kinase and p65 Phosphorylation: ABROGATION OF CYCLIN D1, CYCLOOXYGENASE-2, AND MATRIX METALLOPROTEASE-9 J. Biol. Chem., February 6, 2004; 279(6): 4750 - 4759. [Abstract] [Full Text] [PDF]
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Y. Takada and B. B. Aggarwal Betulinic Acid Suppresses Carcinogen-Induced NF-{kappa}B Activation Through Inhibition of I{kappa}B{alpha} Kinase and p65 Phosphorylation: Abrogation of Cyclooxygenase-2 and Matrix Metalloprotease-9 J. Immunol., September 15, 2003; 171(6): 3278 - 3286. [Abstract] [Full Text] [PDF]
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S. Shishodia, S. Majumdar, S. Banerjee, and B. B. Aggarwal Ursolic Acid Inhibits Nuclear Factor-{kappa}B Activation Induced by Carcinogenic Agents through Suppression of I{kappa}B{alpha} Kinase and p65 Phosphorylation: Correlation with Down-Regulation of Cyclooxygenase 2, Matrix Metalloproteinase 9, and Cyclin D1 Cancer Res., August 1, 2003; 63(15): 4375 - 4383. [Abstract] [Full Text] [PDF]
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 S. Shishodia, P. Potdar, C. G. Gairola, and B. B. Aggarwal Curcumin (diferuloylmethane) down-regulates cigarette smoke-induced NF-{kappa}B activation through inhibition of I{kappa}B{alpha} kinase in human lung epithelial cells: correlation with suppression of COX-2, MMP-9 and cyclin D1 Carcinogenesis, July 1, 2003; 24(7): 1269 - 1279. [Abstract] [Full Text] [PDF]
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Y. Takada, A. Mukhopadhyay, G. C. Kundu, G. H. Mahabeleshwar, S. Singh, and B. B. Aggarwal Hydrogen Peroxide Activates NF-{kappa}B through Tyrosine Phosphorylation of I{kappa}B{alpha} and Serine Phosphorylation of p65: EVIDENCE FOR THE INVOLVEMENT OF I{kappa}B{alpha} KINASE AND Syk PROTEIN-TYROSINE KINASE J. Biol. Chem., June 20, 2003; 278(26): 24233 - 24241. [Abstract] [Full Text] [PDF]
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P. C. Arck, B. Handjiski, E. M. J. Peters, A. S. Peter, E. Hagen, A. Fischer, B. F. Klapp, and R. Paus Stress Inhibits Hair Growth in Mice by Induction of Premature Catagen Development and Deleterious Perifollicular Inflammatory Events via Neuropeptide Substance P-Dependent Pathways Am. J. Pathol., March 1, 2003; 162(3): 803 - 814. [Abstract] [Full Text] [PDF]
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B. Washburn, M. A. Weigand, A. Grosse-Wilde, M. Janke, H. Stahl, E. Rieser, M. R. Sprick, V. Schirrmacher, and H. Walczak TNF-Related Apoptosis-Inducing Ligand Mediates Tumoricidal Activity of Human Monocytes Stimulated by Newcastle Disease Virus J. Immunol., February 15, 2003; 170(4): 1814 - 1821. [Abstract] [Full Text] [PDF]
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H. Li, S. Park, B. Kilburn, M. A. Jelinek, A. Henschen-Edman, D. W. Aswad, M. R. Stallcup, and I. A. Laird-Offringa Lipopolysaccharide-induced Methylation of HuR, an mRNA-stabilizing Protein, by CARM1 J. Biol. Chem., November 15, 2002; 277(47): 44623 - 44630. [Abstract] [Full Text] [PDF]
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M. Chawla-Sarkar, D. W. Leaman, B. S. Jacobs, and E. C. Borden IFN-{beta} Pretreatment Sensitizes Human Melanoma Cells to TRAIL/Apo2 Ligand-Induced Apoptosis J. Immunol., July 15, 2002; 169(2): 847 - 855. [Abstract] [Full Text] [PDF]
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P. K. Baker, A. R. Pettitt, J. R. Slupsky, H. J. Chen, M. A. Glenn, M. Zuzel, and J. C. Cawley Response of hairy cells to IFN-alpha involves induction of apoptosis through autocrine TNF-alpha and protection by adhesion Blood, June 28, 2002; 100(2): 647 - 653. [Abstract] [Full Text] [PDF]
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 R. W. Ganster, B. S. Taylor, L. Shao, and D. A. Geller Complex regulation of human inducible nitric oxide synthase gene transcription by Stat 1 and NF-kappa B PNAS, June 28, 2001; (2001) 151239498. [Abstract] [Full Text] [PDF]
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R. W. Ganster, B. S. Taylor, L. Shao, and D. A. Geller Complex regulation of human inducible nitric oxide synthase gene transcription by Stat 1 and NF-kappa B PNAS, July 17, 2001; 98(15): 8638 - 8643. [Abstract] [Full Text] [PDF]
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