Biomedical subjects

Bharat B Aggarwal

Publications and source records attributed to Bharat B Aggarwal.

At least 37 records · Page 2Linked to original sources

PubMed2006

Genetic deletion of NAD(P)H:quinone oxidoreductase 1 abrogates activation of nuclear factor-kappaB, IkappaBalpha kinase, c-Jun N-terminal kinase, Akt, p38, and p44/42 mitogen-activated protein kinases and potentiates apoptosis.

The NAD(P)H:quinone oxidoreductase 1 (NQO1) is a phase II enzyme that reduces and detoxifies quinones and their derivatives. Although overexpressed in tumor cells, the NQO1 has been linked with the suppression of carcinogenesis, and the effect of NQO1 on tumor necrosis factor (TNF), a cytokine that mediates tumorigenesis through proliferation, invasion, angiogenesis, and metastasis of tumors, is currently unknown. The purpose of our study was to determine the role of NQO1 in TNF cell signaling by using keratinocytes derived from wild-type and NQO1 gene-deleted mice. TNF induced nuclear factor (NF)-kappaB activation in wild-type but not in NQO1-deleted cells. The treatment of wild-type cells with dicoumarol, a known inhibitor of NQO1, also abolished TNF-induced NF-kappaB activation. NF-kappaB activation induced by lipopolysaccharide, phorbol ester, and cigarette smoke, was also abolished in NQO1-deleted cells. The suppression of NF-kappaB activation was mediated through the inhibition of IkappaBalpha kinase activation, IkappaBalpha phosphorylation, and IkappaBalpha degradation. Further, the deletion of NQO1 abolished TNF-induced c-Jun N-terminal kinase, Akt, p38, and p44/p42 mitogen-activated protein kinase activation. TNF also induced the expression of various NF-kappaB-regulated gene products involved in cell proliferation, antiapoptosis, and invasion in wild-type NQO1 keratinocytes but not in NQO1-deleted cells. The suppression of these antiapoptotic gene products increased TNF-induced apoptosis in NQO1-deleted cells. We also found that TNF activated NQO1, and NQO1-specific small interfering RNA abolished the TNF-induced NQO1 activity and NF-kappaB activation. Overall, our results indicate that NQO1 plays a pivotal role in signaling activated by TNF and other inflammatory stimuli and that its suppression is a potential therapeutic strategy to inhibit the proliferation, survival, invasion, and metastasis of tumor cells.

Animals↗

PubMed2006

Plumbagin (5-hydroxy-2-methyl-1,4-naphthoquinone) suppresses NF-kappaB activation and NF-kappaB-regulated gene products through modulation of p65 and IkappaBalpha kinase activation, leading to potentiation of apoptosis induced by cytokine and chemotherapeutic agents.

Plumbagin, derived from the medicinal plant Plumbago zeylanica, modulates cellular proliferation, carcinogenesis, and radioresistance, all known to be regulated by the activation of the transcription factor NF-kappaB, suggesting plumbagin might affect the NF-kappaB activation pathway. We found that plumbagin inhibited NF-kappaB activation induced by TNF, and other carcinogens and inflammatory stimuli (e.g. phorbol 12-myristate 13-acetate, H2O2, cigarette smoke condensate, interleukin-1beta, lipopolysaccharide, and okadaic acid). Plumbagin also suppressed the constitutive NF-kappaB activation in certain tumor cells. The suppression of NF-kappaB activation correlated with sequential inhibition of the tumor necrosis factor (TNF)-induced activation of IkappaBalpha kinase, IkappaBalpha phosphorylation, IkappaBalpha degradation, p65 phosphorylation, p65 nuclear translocation, and the NF-kappaB-dependent reporter gene expression activated by TNF, TNFR1, TRAF2, NIK, IKK-beta, and the p65 subunit of NF-kappaB. Plumbagin also suppressed the direct binding of nuclear p65 and recombinant p65 to the DNA, and this binding was reversed by dithiothreitol both in vitro and in vivo. However, plumbagin did not inhibit p65 binding to DNA when cells were transfected with the p65 plasmid containing cysteine 38 mutated to serine. Plumbagin down-regulated the expression of NF-kappaB-regulated anti-apoptotic (IAP1, IAP2, Bcl-2, Bcl-xL, cFLIP, Bfl-1/A1, and survivin), proliferative (cyclin D1 and COX-2), and angiogenic (matrix metalloproteinase-9 and vascular endothelial growth factor) gene products. This led to potentiation of apoptosis induced by TNF and paclitaxel and inhibited cell invasion. Overall, our results indicate that plumbagin is a potent inhibitor of the NF-kappaB activation pathway that leads to suppression of NF-kappaB-regulated gene products. This may explain its cell growth modulatory, anticarcinogenic, and radiosensitizing effects previously described.

Antineoplastic Agents↗

PubMed2006

A synthetic triterpenoid, CDDO-Me, inhibits IkappaBalpha kinase and enhances apoptosis induced by TNF and chemotherapeutic agents through down-regulation of expression of nuclear factor kappaB-regulated gene products in human leukemic cells.

The C-28 methyl ester of 2-cyano-3,12-dioxoolean-1,9-dien-28-oic acid (CDDO-Me), a synthetic triterpenoid based on naturally occurring ursolic and oleanolic acids, induces apoptosis in tumor cells, induces differentiation, and inhibits inflammatory response through a poorly understood mechanism. Because the nuclear transcription factor nuclear factor kappaB (NF-kappaB) has been shown to suppress apoptosis and promote proliferation and is linked with inflammation and differentiation, we postulated that CDDO-Me modulates NF-kappaB activity and NF-kappaB-regulated gene expression. Using human leukemia cell lines and patient samples, we show that CDDO-Me potently inhibits both constitutive and inducible NF-kappaB activated by tumor necrosis factor (TNF), interleukin (IL)-1beta, phorbol ester, okadaic acid, hydrogen peroxide, lipopolysaccharide, and cigarette smoke. CDDO-Me was more potent than CDDO and its imidazole derivative. NF-kappaB suppression occurred through inhibition of IkappaBalpha kinase activation, IkappaBalpha phosphorylation, IkappaBalpha degradation, p65 phosphorylation, p65 nuclear translocation, and NF-kappaB-mediated reporter gene transcription. This inhibition correlated with suppression of NF-kappaB-dependent genes involved in antiapoptosis (IAP2, cFLIP, TRAF1, survivin, and bcl-2), proliferation (cyclin d1 and c-myc), and angiogenesis (VEGF, cox-2, and mmp-9). CDDO-Me also potentiated the cytotoxic effects of TNF and chemotherapeutic agents. Overall, our results suggest that CDDO-Me inhibits NF-kappaB through inhibition of IkappaBalpha kinase, leading to the suppression of expression of NF-kappaB-regulated gene products and enhancement of apoptosis induced by TNF and chemotherapeutic agents.

Active Transport, Cell Nucleus↗

PubMed2006

Acetyl-11-keto-beta-boswellic acid potentiates apoptosis, inhibits invasion, and abolishes osteoclastogenesis by suppressing NF-kappa B and NF-kappa B-regulated gene expression.

Acetyl-11-keto-beta-boswellic acid (AKBA), a component of an Ayurvedic therapeutic plant Boswellia serrata, is a pentacyclic terpenoid active against a large number of inflammatory diseases, including cancer, arthritis, chronic colitis, ulcerative colitis, Crohn's disease, and bronchial asthma, but the mechanism is poorly understood. We found that AKBA potentiated the apoptosis induced by TNF and chemotherapeutic agents, suppressed TNF-induced invasion, and inhibited receptor activator of NF-kappaB ligand-induced osteoclastogenesis, all of which are known to require NF-kappaB activation. These observations corresponded with the down-regulation of the expression of NF-kappaB-regulated antiapoptotic, proliferative, and angiogenic gene products. As examined by DNA binding, AKBA suppressed both inducible and constitutive NF-kappaB activation in tumor cells. It also abrogated NF-kappaB activation induced by TNF, IL-1beta, okadaic acid, doxorubicin, LPS, H2O2, PMA, and cigarette smoke. AKBA did not directly affect the binding of NF-kappaB to the DNA but inhibited sequentially the TNF-induced activation of IkappaBalpha kinase (IKK), IkappaBalpha phosphorylation, IkappaBalpha ubiquitination, IkappaBalpha degradation, p65 phosphorylation, and p65 nuclear translocation. AKBA also did not directly modulate IKK activity but suppressed the activation of IKK through inhibition of Akt. Furthermore, AKBA inhibited the NF-kappaB-dependent reporter gene expression activated by TNFR type 1, TNFR-associated death domain protein, TNFR-associated factor 2, NF-kappaB-inducing kinase, and IKK, but not that activated by the p65 subunit of NF-kappaB. Overall, our results indicated that AKBA enhances apoptosis induced by cytokines and chemotherapeutic agents, inhibits invasion, and suppresses osteoclastogenesis through inhibition of NF-kappaB-regulated gene expression.

Animals↗

PubMed2006

Molecular targets of dietary agents for prevention and therapy of cancer.

While fruits and vegetables are recommended for prevention of cancer and other diseases, their active ingredients (at the molecular level) and their mechanisms of action less well understood. Extensive research during the last half century has identified various molecular targets that can potentially be used not only for the prevention of cancer but also for treatment. However, lack of success with targeted monotherapy resulting from bypass mechanisms has forced researchers to employ either combination therapy or agents that interfere with multiple cell-signaling pathways. In this review, we present evidence that numerous agents identified from fruits and vegetables can interfere with several cell-signaling pathways. The agents include curcumin (turmeric), resveratrol (red grapes, peanuts and berries), genistein (soybean), diallyl sulfide (allium), S-allyl cysteine (allium), allicin (garlic), lycopene (tomato), capsaicin (red chilli), diosgenin (fenugreek), 6-gingerol (ginger), ellagic acid (pomegranate), ursolic acid (apple, pears, prunes), silymarin (milk thistle), anethol (anise, camphor, and fennel), catechins (green tea), eugenol (cloves), indole-3-carbinol (cruciferous vegetables), limonene (citrus fruits), beta carotene (carrots), and dietary fiber. For instance, the cell-signaling pathways inhibited by curcumin alone include NF-kappaB, AP-1, STAT3, Akt, Bcl-2, Bcl-X(L), caspases, PARP, IKK, EGFR, HER2, JNK, MAPK, COX2, and 5-LOX. The active principle identified in fruit and vegetables and the molecular targets modulated may be the basis for how these dietary agents not only prevent but also treat cancer and other diseases. This work reaffirms what Hippocrates said 25 centuries ago, let food be thy medicine and medicine be thy food.

Animals↗

PubMed2006

Pomegranate juice, total pomegranate ellagitannins, and punicalagin suppress inflammatory cell signaling in colon cancer cells.

Phytochemicals from fruits such as the pomegranate (Punica granatum L) may inhibit cancer cell proliferation and apoptosis through the modulation of cellular transcription factors and signaling proteins. In previous studies, pomegranate juice (PJ) and its ellagitannins inhibited proliferation and induced apoptosis in HT-29 colon cancer cells. The present study examined the effects of PJ on inflammatory cell signaling proteins in the HT-29 human colon cancer cell line. At a concentration of 50 mg/L PJ significantly suppressed TNFalpha-induced COX-2 protein expression by 79% (SE = 0.042), total pomegranate tannin extract (TPT) 55% (SE = 0.049), and punicalagin 48% (SE = 0.022). Additionally, PJ reduced phosphorylation of the p65 subunit and binding to the NFkappaB response element 6.4-fold. TPT suppressed NFkappaB binding 10-fold, punicalagin 3.6-fold, whereas ellagic acid (EA) (another pomegranate polyphenol) was ineffective. PJ also abolished TNFalpha-induced AKT activation, needed for NFkappaB activity. Therefore, the polyphenolic phytochemicals in the pomegranate can play an important role in the modulation of inflammatory cell signaling in colon cancer cells.

Anti-Inflammatory Agents↗

PubMed2006

Guggulsterone inhibits osteoclastogenesis induced by receptor activator of nuclear factor-kappaB ligand and by tumor cells by suppressing nuclear factor-kappaB activation.

Bone resorption is commonly associated with aging and with certain types of cancer, including multiple myeloma and breast cancer. What induces bone resorption is not fully understood, but the role of osteoclasts is well established. Recently, receptor activator of nuclear factor-kappaB (NF-kappaB) ligand (RANKL), a member of the tumor necrosis factor superfamily, was implicated as a major mediator of bone resorption, suggesting that agents that can suppress RANKL signaling have the potential to inhibit bone resorption or osteoclastogenesis. Guggulsterone [4,17(20)-pregnadiene-3,16-dione], isolated from the guggul tree Commiphora mukul and used to treat osteoarthritis and bone fractures, was recently shown to antagonize the farnesoid X receptor, decrease the expression of bile acid-activated genes, and suppress the NF-kappaB activation induced by various carcinogens. We investigated whether guggulsterone could modulate RANKL signaling and osteoclastogenesis induced by RANKL or tumor cells. We found that treatment of monocytes with guggulsterone suppressed RANKL-activated NF-kappaB activation (as indicated by gel-shift assay) and that this suppression correlated with inhibition of IkappaBalpha kinase and phosphorylation and degradation of IkappaBalpha, an inhibitor of NF-kappaB. Guggulsterone also suppressed the differentiation of monocytes to osteoclasts in a dose-dependent and time-dependent manner. Suppression of osteoclastogenesis by the NF-kappaB-specific inhibitory peptide implies a link between NF-kappaB and osteoclastogenesis. Finally, differentiation to osteoclasts induced by coincubating human breast tumor cells (MDA-MB-468) or human multiple myeloma (U266) cells with monocytes was also completely suppressed by guggulsterone. Collectively, our results indicate that guggulsterone suppresses RANKL and tumor cell-induced osteoclastogenesis by suppressing the activation of NF-kappaB.

Bone Resorption↗

PubMed2006

Association of activated transcription factor nuclear factor kappab with chemoradiation resistance and poor outcome in esophageal carcinoma.

PURPOSE: The lack of effective treatment for localized esosphageal cancer leads to poor patient outcome. Nuclear factor kappaB (NF-kappaB), a transcriptional factor, is constitutively activated or treatment induced in esophageal cancer and may influence treatment outcomes. PATIENTS AND METHODS: Pre- and post-treatment cancer specimens from patients enrolled onto a clinical trial were studied for the expression of activated NF-kappaB protein and it was correlated with histologic features, pathologic response, metastatic potential, overall survival (OS), and disease-free survival (DFS). RESULTS: Forty-three patients undergoing the same therapy on a protocol were studied. Twenty-one (72%) of 29 patients achieving less than complete pathologic response (pathCR) had NF-kappaB positive cancer, but only one (7%) of 14 patients achieving pathCR had NF-kappaB positive cancer (P = < .001). Activated NF-kappaB was significantly associated with aggressive pathologic features such as perineural, lymphatic, and/or vascular invasion (P = .0004). Eight (38%) of 21 NF-kappaB positive patients developed metastases compared to none of 22 NF-kappaB negative patients (P = .001). At a median follow-up of 23 months, 10 (48%) of 21 NF-kappaB positive patients had died compared to only one (5%) of 22 NF-kappaB negative patients (P = .0013). Observations were similar for DFS (P = .0006). In a multivariate model (using baseline stage, pathCR or less than pathCR, age, presence of metastatic lymph nodes in the surgical specimen, and NF-kappaB expression) NF-kappaB activation was the only independent predictor of DFS (P = .010) and OS (P = .015). CONCLUSION: Our data suggest that esophageal cancers with activated NF-kappaB have aggressive clinical biology and poor treatment outcome. Additional understanding of NF-kappaB regulated pathways may uncover potential therapeutic targets.

Adult↗

PubMed2006

Mutant human tumor suppressor p53 modulates the activation of mitogen-activated protein kinase and nuclear factor-kappaB, but not c-Jun N-terminal kinase and activated protein-1.

The roles of the mitogen-activated kinase protein (MAPK) pathway, nuclear factor-kappa B (NF-kappaB), and activator protein-1 (AP-1) in cellular responses to growth factors and mitogen are well established. However, the manner by which these proliferative pathways are affected by the tumor suppressor protein p53 is not fully understood. We report here the results of an investigation of the status of p53 on two human melanoma cell lines with wild-type p53 (SK-Mel-186) or mutant p53 (SK-Mel-110). The basal levels of the activated extracellular-signal regulated kinases 1 and 2 (ERK1/2) were high in cells with wild-type p53, but low in cells with mutant p53. The 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced activation of ERK1/2 through the phosphorylation of threonine and tyrosine at 202 and 204, respectively, was demonstrated in both cell lines, however, in a discrete manner. TPA-induced activation of ERK1/2 was sustained in wild-type p53 cells, while only a transient activation was seen in mutant p53 cells. Inhibition of MAPK kinase (MEK), an upstream kinase, by U0126, blocked TPA-induced activation of ERK1/2 in wild-type p53 cells and in mutant p53 cells. Treatment of wild-type p53 (SK-Mel 186) cells with small interfering RNA (siRNA) of p53 displayed a transient induction of activation of ERK1/2 following TPA treatment, indicating that p53 has a role in the regulation of the activation of ERK1/2. NF-kappaB activity decreased significantly in cells with wild-type p53, while enhanced NF-kappaB activity was evident in cells with mutant p53. The expression of either wild-type or mutant p53 had a similar effect on TPA-induced Jun N-terminal kinase (JNK) activation, indicating specificity for the ERK pathway. Similarly, AP-1 binding activity showed a transient variation in both cell lines after TPA treatment but with different kinetics. These observations suggest that both wild-type and mutant p53 can modulate the activation pathways for ERK1/2, and NF-kappaB distinctively, while modulating the pathways of JNK and AP-1 similarly. These differences may influence cellular processes such as proliferation, differentiation, and apoptosis.

Base Sequence↗

PubMed2006

Withanolides potentiate apoptosis, inhibit invasion, and abolish osteoclastogenesis through suppression of nuclear factor-kappaB (NF-kappaB) activation and NF-kappaB-regulated gene expression.

The plant Withania somnifera Dunal (Ashwagandha), also known as Indian ginseng, is widely used in the Ayurvedic system of medicine to treat tumors, inflammation, arthritis, asthma, and hypertension. Chemical investigation of the roots and leaves of this plant has yielded bioactive withanolides. Earlier studies showed that withanolides inhibit cyclooxygenase enzymes, lipid peroxidation, and proliferation of tumor cells. Because several genes that regulate cellular proliferation, carcinogenesis, metastasis, and inflammation are regulated by activation of nuclear factor-kappaB (NF-kappaB), we hypothesized that the activity of withanolides is mediated through modulation of NF-kappaB activation. For this report, we investigated the effect of the withanolide on NF-kappaB and NF-kappaB-regulated gene expression activated by various carcinogens. We found that withanolides suppressed NF-kappaB activation induced by a variety of inflammatory and carcinogenic agents, including tumor necrosis factor (TNF), interleukin-1beta, doxorubicin, and cigarette smoke condensate. Suppression was not cell type specific, as both inducible and constitutive NF-kappaB activation was blocked by withanolides. The suppression occurred through the inhibition of inhibitory subunit of IkappaB alpha kinase activation, IkappaB alpha phosphorylation, IkappaB alpha degradation, p65 phosphorylation, and subsequent p65 nuclear translocation. NF-kappaB-dependent reporter gene expression activated by TNF, TNF receptor (TNFR) 1, TNFR-associated death domain, TNFR-associated factor 2, and IkappaB alpha kinase was also suppressed. Consequently, withanolide suppressed the expression of TNF-induced NF-kappaB-regulated antiapoptotic (inhibitor of apoptosis protein 1, Bfl-1/A1, and FADD-like interleukin-1beta-converting enzyme-inhibitory protein) and metastatic (cyclooxygenase-2 and intercellular adhesion molecule-1) gene products, enhanced the apoptosis induced by TNF and chemotherapeutic agents, and suppressed cellular TNF-induced invasion and receptor activator of NF-kappaB ligand-induced osteoclastogenesis. Overall, our results indicate that withanolides inhibit activation of NF-kappaB and NF-kappaB-regulated gene expression, which may explain the ability of withanolides to enhance apoptosis and inhibit invasion and osteoclastogenesis.

Animals↗

PubMed2006

Pretherapy nuclear factor-kappaB status, chemoradiation resistance, and metastatic progression in esophageal carcinoma.

BACKGROUND: Transcriptional factor nuclear factor-kappaB (NF-kappaB) seems to be associated with aggressive clinical biology (chemoradiation resistance and metastatic progression) of esophageal cancer. We hypothesized that activated NF-kappaB would define clinical biology irrespective of the type of chemotherapy or sequence administered. METHODS: Pretherapy and/or posttherapy cancer specimens were examined for activated NF-kappaB and correlated with pathologic response to chemoradiation, metastatic potential, overall survival, disease-free survival, and type of chemotherapy or sequence used. FINDINGS: Eighty patients undergoing chemotherapy and concurrent radiation were studied. Activated NF-kappaB prior to any therapy was associated with the lack of complete pathologic response (pathCR, P = 0.006). Forty-five (78%) of 58 patients achieving <pathCR had activated NF-kappaB in pretherapy and/or posttherapy cancer specimens versus 2 (9%) of 22 patients with pathCR (P = 0.001). Twenty-four (51%) of 47 patients with activated NF-kappaB in cancer developed metastases versus 7 (21%) of 22 patients with negative NF-kappaB in cancer (P = 0.01). At a median follow-up of 32 months, 25 (53%) of 47 patients with activated NF-kappaB cancer had died versus 3 (9%) of 33 patients with negative NF-kappaB cancer. NF-kappaB activation was the only independent predictor of disease-free survival (P = 0.01) and overall survival (P = 0.007) in a multivariate model. The class of chemotherapy or its sequence had no effect on NF-kappaB expression or patient outcome. CONCLUSIONS: Our data are the first to show that pretreatment-activated NF-kappaB significantly correlates with clinical biology of esophageal cancer, and most importantly, with pathCR. To therapeutically exploit NF-kappaB-regulated genes and their pathways, further research is warranted.

Adult↗

PubMed2006

1'-Acetoxychavicol acetate inhibits RANKL-induced osteoclastic differentiation of RAW 264.7 monocytic cells by suppressing nuclear factor-kappaB activation.

Osteoclastogenesis is commonly associated with various age-related diseases, including cancer. A member of the tumor necrosis factor superfamily, receptor activator of nuclear factor-kappaB (NF-kappaB) ligand (RANKL), has been shown to play a critical role in osteoclast formation and bone resorption. Thus, agents that suppress RANKL signaling have a potential to suppress bone loss. In this report, we investigated the effect of 1'-acetoxychavicol acetate (ACA), a component of Alpina galanga, on RANKL signaling and consequent osteoclastogenesis in RAW 264.7 cells, a murine monocytic cell line. Treatment of these cells with RANKL activated NF-kappaB, and coexposure of the cells to ACA completely suppressed RANKL-induced NF-kappaB activation in a time- and concentration-dependent manner. The suppression of NF-kappaB by ACA was mediated through suppression of RANKL-induced activation of IkappaBalpha kinase, IkappaBalpha phosphorylation, and IkappaBalpha degradation. Furthermore, incubation of monocytic cells with RANKL induced osteoclastogenesis, and ACA suppressed it. Inhibition of osteoclastogenesis was maximal when cells were simultaneously exposed to ACA and RANKL and minimum when ACA was added 2 days after RANKL. ACA also inhibited the osteoclastogenesis induced by human breast cancer MCF-7 cells, multiple myeloma MM1 cells, and head and neck squamous cell carcinoma LICR-LON-HN5 cells. These results indicate that ACA is an effective blocker of RANKL-induced NF-kappaB activation and of osteoclastogenesis induced by RANKL and tumor cells, suggesting its potential as a therapeutic agent for osteoporosis and cancer-associated bone loss.

Animals↗

PubMed2006

Honokiol potentiates apoptosis, suppresses osteoclastogenesis, and inhibits invasion through modulation of nuclear factor-kappaB activation pathway.

Recent reports have indicated that honokiol can induce apoptosis, suppress tumor growth, and inhibit angiogenesis. In this report, we found that honokiol potentiated the apoptosis induced by tumor necrosis factor (TNF) and chemotherapeutic agents, suppressed TNF-induced tumor cell invasion, and inhibited RANKL-induced osteoclastogenesis, all of which are known to require nuclear factor-kappaB (NF-kappaB) activation. Honokiol suppressed NF-kappaB activation induced by a variety of inflammatory stimuli, and this suppression was not cell type specific. Further studies showed that honokiol blocked TNF-induced phosphorylation, ubiquitination, and degradation of IkappaBalpha through the inhibition of activation of IkappaBalpha kinase and of Akt. This led to suppression of the phosphorylation and nuclear translocation of p65 and NF-kappaB-dependent reporter gene expression. Magnolol, a honokiol isomer, was equally active. The expression of NF-kappaB-regulated gene products involved in antiapoptosis (IAP1, IAP2, Bcl-x(L), Bcl-2, cFLIP, TRAF1, and survivin), proliferation (cyclin D1, cyclooxygenase-2, and c-myc), invasion (matrix metalloproteinase-9 and intercellular adhesion molecule-1), and angiogenesis (vascular endothelial growth factor) were also down-regulated by honokiol. Honokiol also down-regulated NF-kappaB activation in in vivo mouse dorsal skin model. Thus, overall, our results indicate that NF-kappaB and NF-kappaB-regulated gene expression inhibited by honokiol enhances apoptosis and suppresses osteoclastogenesis and invasion.

Animals↗

PubMed2006

From traditional Ayurvedic medicine to modern medicine: identification of therapeutic targets for suppression of inflammation and cancer.

Cancer is a hyperproliferative disorder that involves transformation, dysregulation of apoptosis, proliferation, invasion, angiogenesis and metastasis. Extensive research during the last 30 years has revealed much about the biology of cancer. Drugs used to treat most cancers are those that can block cell signalling, including growth factor signalling (e.g., epidermal growth factor); prostaglandin production (e.g., COX-2); inflammation (e.g., inflammatory cytokines: NF-kappaB, TNF, IL-1, IL-6, chemokines); drug resistance gene products (e.g., multi-drug resistance); cell cycle proteins (e.g., cyclin D1 and cyclin E); angiogenesis (e.g., vascular endothelial growth factor); invasion (e.g., matrix metalloproteinases); antiapoptosis (e.g., bcl-2, bcl-X(L), XIAP, survivin, FLIP); and cellular proliferation (e.g., c-myc, AP-1, growth factors). Numerous reports have suggested that Ayurvedic plants and their components mediate their effects by modulating several of these recently identified therapeutic targets. However, Ayurvedic medicine requires rediscovery in light of our current knowledge of allopathic (modern) medicine. The focus of this review is to elucidate the Ayurvedic concept of cancer, including its classification, causes, pathogenesis and prevention; surgical removal of tumours; herbal remedies; dietary modifications; and spiritual treatments.

Animals↗

PubMed2005

Suberoylanilide hydroxamic acid potentiates apoptosis, inhibits invasion, and abolishes osteoclastogenesis by suppressing nuclear factor-kappaB activation.

Because of its ability to suppress tumor cell proliferation, angiogenesis, and inflammation, the histone deacetylase inhibitor suberoylanilide hydroxamic acid (SAHA) is currently in clinical trials. How SAHA mediates its effects is poorly understood. We found that in several human cancer cell lines, SAHA potentiated the apoptosis induced by tumor necrosis factor (TNF) and chemotherapeutic agents and inhibited TNF-induced invasion and receptor activator of NF-kappaB ligand-induced osteoclastogenesis, all of which are known to require NF-kappaB activation. These observations corresponded with the down-regulation of the expression of anti-apoptotic (IAP1, IAP2, X chromosome-linked IAP, Bcl-2, Bcl-x(L), TRAF1, FLIP, and survivin), proliferative (cyclin D1, cyclooxygenase 2, and c-Myc), and angiogenic (ICAM-1, matrix metalloproteinase-9, and vascular endothelial growth factor) gene products. Because several of these genes are regulated by NF-kappaB, we postulated that SAHA mediates its effects by modulating NF-kappaB and found that SAHA suppressed NF-kappaB activation induced by TNF, IL-1beta, okadaic acid, doxorubicin, lipopolysaccharide, H(2)O(2), phorbol myristate acetate, and cigarette smoke; the suppression was not cell type-specific because both inducible and constitutive NF-kappaB activation was inhibited. We also found that SAHA had no effect on direct binding of NF-kappaB to the DNA but inhibited sequentially the TNF-induced activation of IkappaBalpha kinase, IkappaBalpha phosphorylation, IkappaBalpha ubiquitination, IkappaBalpha degradation, p65 phosphorylation, and p65 nuclear translocation. Furthermore, SAHA inhibited the NF-kappaB-dependent reporter gene expression activated by TNF, TNFR1, TRADD, TRAF2, NF-kappaB-inducing kinase, IkappaBalpha kinase, and the p65 subunit of NF-kappaB. Overall, our results indicated that NF-kappaB and NF-kappaB-regulated gene expression inhibited by SAHA can enhance apoptosis and inhibit invasion and osteoclastogenesis.

Animals↗

PubMed2005

The nuclear transcription factor kappaB/bcl-2 pathway correlates with pathologic complete response to doxorubicin-based neoadjuvant chemotherapy in human breast cancer.

PURPOSE: Molecular factors involved in apoptosis may affect breast cancer response to chemotherapy. Herein, we studied the nuclear factor kappaB (NF-kappaB)/bcl-2 pathway to determine whether or not activation of this antiapoptotic pathway was associated with a poor response of human breast cancer to anthracycline-based neoadjuvant chemotherapy. EXPERIMENTAL DESIGN: We studied 82 human breast cancer samples from patients treated with neoadjuvant doxorubicin-based chemotherapy and studied whether or not nuclear location of the transcription factor NF-kappaB was associated with expression of bcl-2 and bax and whether or not expression of these proteins correlated with chemotherapy response. Protein expression was measured with immunohistochemical staining. A dedicated breast cancer pathologist who was unaware of the clinical outcome data dichotomized the slides as positive or negative based on the presence or absence of cytoplasmic staining for bcl-2 and bax or nuclear staining for NF-kappaB. RESULTS: Sixty-one percent of the tumors were positive for bcl-2, 85% were positive for bax, and 16% were positive for NF-kappaB. All bcl-2-positive tumors were also bax positive (P < 0.0001) and all NF-kappaB-positive tumors were both bcl-2 positive (P = 0.001) and bax positive (P = 0.113). Eleven of the 82 patients (13%) had a pathologic complete response (pCR) to chemotherapy. Patients with positive staining tumors for any of the markers less commonly achieved a pCR to chemotherapy than those with negative tumor staining. The pCR rates were NF-kappaB positive 0% (0 of 13) versus NF-kappaB negative 13% (11 of 69; P = 0.130); bcl-2 positive 4% (2 of 49) versus bcl-2 negative 27% (9 of 33; P = 0.004); and bax positive 6% (4 of 69) versus bax negative 58% (7 of 12; P < 0.001). CONCLUSION: We conclude that nuclear localization of NF-kappaB correlates with bcl-2 and bax expression and that the NF-kappaB/bcl-2 pathway may be associated with a poor response to neoadjuvant doxorubicin-based chemotherapy.

Antineoplastic Agents↗

PubMed2005

Synthetic Vpr protein activates activator protein-1, c-Jun N-terminal kinase, and NF-kappaB and stimulates HIV-1 transcription in promonocytic cells and primary macrophages.

The human immunodeficiency virus (HIV) Vpr protein plays a critical role in AIDS pathogenesis, especially by allowing viral replication within nondividing cells such as mononuclear phagocytes. Most of the data obtained so far have been in experiments with endogenous Vpr protein; therefore the effects of extracellular Vpr protein remain largely unknown. We used synthetic Vpr protein to activate nuclear transcription factors activator protein-1 (AP-1) and NF-kappaB in the promonocytic cell line U937 and in primary macrophages. Synthetic HIV-1 Vpr protein activated AP-1, c-Jun N-terminal kinase, and MKK7 in both U937 cells and primary macrophages. Synthetic Vpr activated NF-kappaB in primary macrophages and to a lesser extent in U937 cells. Because synthetic Vpr activated AP-1 and NF-kappaB, which bind to the HIV-1 long terminal repeat, we investigated the effect of synthetic Vpr on HIV-1 replication. We observed that synthetic Vpr stimulated HIV-1 long terminal repeat in U937 cells and enhanced viral replication in chronically infected U1 promonocytic cells. Similarly, synthetic Vpr stimulated HIV-1 replication in acutely infected primary macrophages. Activation of transcription factors and enhancement of viral replication in U937 cells and primary macrophages were mediated by both the N-terminal and the C-terminal moieties of synthetic Vpr. Therefore, our results suggest that extracellular Vpr could fuel the progression of AIDS via stimulation of HIV-1 provirus present in such cellular reservoirs as mononuclear phagocytes in HIV-infected patients.

Acquired Immunodeficiency Syndrome↗

PubMed2005

Zerumbone abolishes NF-kappaB and IkappaBalpha kinase activation leading to suppression of antiapoptotic and metastatic gene expression, upregulation of apoptosis, and downregulation of invasion.

Zerumbone found in subtropical ginger Zingiber zerumbet Smith exhibits antiproliferative and antiinflammatory activities but underlying molecular mechanisms are poorly understood. As several genes that regulate proliferation and apoptosis are regulated by nuclear factor (NF)-kappaB, we hypothesized that zerumbone mediates its activity through the modulation of NF-kappaB activation. We found that zerumbone suppressed NF-kappaB activation induced by tumor necrosis factor (TNF), okadaic acid, cigarette smoke condensate, phorbol myristate acetate, and H2O2 and that the suppression was not cell type specific. Interestingly, alpha-humulene, a structural analogue of zerumbone lacking the carbonyl group, was completely inactive. Besides being inducible, constitutively active NF-kappaB was also inhibited. NF-kappaB inhibition by zerumbone correlated with sequential suppression of the IkappaBalpha kinase activity, IkappaBalpha phosphorylation, IkappaBalpha degradation, p65 phosphorylation, p65 nuclear translocation, and p65 acylation. Zerumbone also inhibited the NF-kappaB-dependent reporter gene expression activated by TNF, TNFR1, TRADD, TRAF2, NIK, and IKK but not that activated by the p65 subunit of NF-kappaB. NF-kappaB-regulated gene products, such as cyclin D1, COX-2, MMP-9, ICAM-1, c-Myc, survivin, IAP1, IAP2, XIAP, Bcl-2, Bcl-xL, Bfl-1/A1, TRAF1 and FLIP, were all downregulated by zerumbone. This downregulation led to the potentiation of apoptosis induced by cytokines and chemotherapeutic agents. Zerumbone's inhibition of expression of these NF-kappaB-regulated genes also correlated with the suppression of TNF-induced invasion activity. Overall, our results indicated that zerumbone inhibits the activation of NF-kappaB and NF-kappaB-regulated gene expression induced by carcinogens and that this inhibition may provide a molecular basis for the prevention and treatment of cancer by zerumbone.

Apoptosis↗