Cancer Research 68, 9519, November 15, 2008. doi: 10.1158/0008-5472.CAN-08-1549
© 2008 American Association for Cancer Research
Systems Biology and Emerging Technologies |
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Kinase Inhibitor IKI-1 Conferred Tumor Necrosis Factor Sensitivity to Pancreatic Cancer Cells and a Xenograft Tumor Model
Yixian Zhang,
Maria Gavriil,
Judy Lucas,
Sreekala Mandiyan,
Max Follettie,
Veronica Diesl,
Fuk-Wah Sum,
Dennis Powell,
Steve Haney,
Robert Abraham and
Kim Arndt
Department of Oncology, Wyeth Research, Pearl River, New York
Requests for reprints: Yixian Zhang, Enzon Pharmaceutical, 20 Kingsbridge Road, Piscataway, NJ 08854. Phone: 732-980-4914; Fax: 732-885-2950; E-mail: yixian.zhang{at}enzon.com.
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Abstract
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Tumor necrosis factor 
(TNF) has been used to treat patients with certain tumor types. However, its antitumor activity has been undermined by the activation of I
B kinase (IKK), which in turn activates nuclear factor-B (NF-B) to help cancer cells survive. Therefore, inhibition of TNF-induced IKK activity with specific IKK inhibitor represents an attractive strategy to treat cancer patients. This study reveals IKI-1 as a potent small molecule inhibitor of IKK and IKKβ, which effectively blocked TNF-mediated IKK activation and subsequent NF-B activity. Using gene profiling analysis, we show that IKI-1 blocked most of the TNF-mediated mRNA expression, including many genes that play important roles in cell survival. We further show that in vitro and in vivo combination of TNF with IKI-1 had superior potency than either agent alone. This increased potency was due primarily to the increased apoptosis in the presence of both TNF and IKI-1. Additionally, IKKβ small interfering RNA transfected cells were more sensitive to the treatment of TNF. The study suggests that the limited efficacy of TNF in cancer treatment was due in part to the activation of NF-B, allowing tumor cells to escape apoptosis. Therefore, the combination of IKI-1 with TNF may improve the efficacy of TNF for certain tumor types. [Cancer Res 2008;68(22):9519–24]
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Introduction
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Tumor necrosis factor (TNF) is a pleiotropic protein that initially isolated from the serum of mice treated with bacterial endotoxin (1–3). It is involved in many diseases, such as autoimmune diseases and cancer. Interestingly, TNF has been shown to have antitumor activity in various tumors (4, 5). Multiple clinical trials have been conducted to treat cancer patients with various tumor types with mixed success (4, 5). However, many tumors have been found to be resistant to TNF (6, 7). Additionally, TNF has been shown to cause significant systemic toxicity, which prevents it from becoming an effective anticancer agent (6, 8). Currently, its usages are limited to limb perfusion and isolated hepatic perfusion for the treatment of locally advanced solid tumors (4, 5).
TNF mediates its biological effect through its receptor TNF-R1 and TNF-R2 (9, 10), which recruit many cellular proteins and consequently regulate multiple signaling pathways. One of the major pathways TNF activates is the IB kinase (IKK)/nuclear factor-B (NF-B) pathway. NF-B is regulated by its upstream kinase, IKK complex, which comprises at least IKK and IKKβ and a noncatalytic regulatory protein, NEMO (11–13). In cytoplasm, NF-B forms a tight complex with IB, which blocks the nuclear translocation signal of NF-B (11–13). When IKK is activated, it phosphorylates IB, which in turn triggers ubiquitination and proteasome-dependent degradation of IB (11–13). NF-B is thus released and translocated to the nucleus, where it regulates an array of genes responsible for cell survival and growth, which paradoxically blocked the apoptotic potential exerted by TNF. Using genetic or pharmacologic approaches, several groups showed clearly that the potency of TNF can be dramatically increased in certain tumors when NF-B activity is inhibited (14–16). Because NF-B is controlled primarily by IKK, it is conceivable that blocking IKK will result in dramatic cell death, thus improving the anticancer activity of TNF. This notion has been strongly supported by many studies using nonselective IKK inhibitors (17–22). Recently, Frelin and colleagues (23) showed that AS602868, a specific small molecule IKKβ inhibitor, potentiated the proapoptotic effect of TNF in Jukat leukemia cells.
We show here that IKI-1 is a potent IKK inhibitor,1 which blocked TNF-mediated activation of IKK/NF-B pathway and downstream target genes in pancreatic tumor cells. Additionally, IKI-1 greatly potentiated the effect of TNF on the growth of tumor cells through activation of apoptosis. Furthermore, the combination resulted in shrinkage of tumors grown in nude mice, suggesting that combination of an IKK inhibitor with TNF is a potential treatment for irresectable pancreatic cancer.
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Materials and Methods
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Materials. All cell culture reagents were purchased from Invitrogen, except for charcoal-stripped fetal bovine serum (FBS), which was obtained from Hyclone. Steady-Glo Lucifierase Assay System and CellTiter-Glo were purchased from Promega. Apoptotic DNA-Ladder kit was purchased from Roche Applied Science. CaspaseOne kit was purchased from Promega. Small interfering RNAs (siRNA) ON-TARGETplus SMARTpool for IKK, IKKβ and nontarget control were purchased from Dharmacon. Inhibitor IV and ZVAD-FMK were purchased from Calbiochem. The synthesis of IKI-1 will be described in a future publication.1
Cell culture and Western blot analysis. BxPC3 cells were obtained from American Type Culture Collection and were maintained in DMEM supplemented with 10% FBS at 37°C in a humidified atmosphere of 5% CO2 and 95% air. Cells were harvested in M-PER reagent (Pierce). Thirty micrograms of protein were electrophoresed on an 8% to 16% SDS-PAGE gel and then transferred to polyvinylidene difluoride using a Bio-Rad liquid transfer apparatus. The Western blot analysis was performed with enhanced chemiluminescence (SuperSignal, Pierce) using the anti-IB antibody (Santa Cruz) at 1 µg/mL and the horseradish peroxidase–conjugated antirabbit secondary antibody (Bio-Rad) diluted at 1:4,000. Phosphorylation of IB was detected using anti–phosphorylated IB antibodies (Cell Signaling Technology). IKKβ was detected using the anti-IKKβ antibody (Cell Signaling Technology).
Transfection of siRNA. Two thousand BxPC3 cells were plated in each well of 96-well plates. siRNA of IKKβ or nontarget was prepared in OptiMem (Invitrogen) medium containing Optifect (Invitrogen) and added to each well. Twenty-four hours later, siRNA was removed and replaced with fresh medium. After 24 h, cells were treated with or without TNF (final concentration, 5 ng/mL). Cell growth was measured after 96 h after TNF treatment with the addition of 100 µL of CellTiter-Glo reagent, and signals were read with a Vector reader (PerkinElmer).
Apo-One homogeneous caspase-3/caspase-7 assay (Promega). Ten thousand BxPC3 cells were plated in each well of 96-well plates. Cells were treated with various concentration of IKI-1, as indicated for 1 h before the addition of TNF (5 ng/mL). Twenty four hours later, 100 µL of Apo-One reagent was added to each well containing 100 µL of culture medium. After 1 h of incubation, fluorescence of the samples was determined with a fluorescence plate reader (GeminiXS, Molecular Devices).
Cell death detection ELISA. Ten thousand BxPC3 cells were plated in each well of 96-well plates. Cells were treated with IKI-1 for 1 h before the addition of TNF. After 24 h, cell death was evaluated according to manufacturer's instruction (Roche Applied Science).
NF-B nuclear translocation assay. Six thousand BxPC3 cells were plated in each well of clear-bottomed, 96-well plates (PerkinElmer) and incubated overnight at 37°C. On the next day, cells were treated with IKI-1 for 1 h before the addition of TNF (final concentration, 5 ng/mL). NF-B nuclear translocation assay was performed using HitKit HCS reagent (Thermo Fisher Scientific), according to manufacturer's protocol. NF-B signals were detected using an ArrayScan VTI HCS Reader (Thermo Fisher Scientific).
For the standard immunofluorescence staining procedure, BxPC3 cells were incubated on Biocoat chamber slides (BD Biosciences) overnight. Cells were treated with IKI-1 for 1 h and then with 5 ng/mL TNF for 20 min. The medium was aspirated, and cells were fixed with 3.7% formaldehyde in PBS for 10 min at room temperature, followed by permeabilization with 0.15% Triton X-100 for 10 min. Cell were rehydrated in PBS and then incubated in Cellomics NF-B p65 antibody for 1 h at 37°C. Cells were washed in PBS and stained with Alexa Fluor 488 secondary antibody (Cellomics) for 1 h at room temperature. The slide was washed, and the coverslip was mounted using Prolong Gold Antifade with 4',6-diamidino-2-phenylindole (Invitrogen).
Gene profiling experiments. RNA extraction and preparation, chip hybridization and data reduction, and data filtering and statistics were similar to those detailed in ref. 24, with the exception that U95v2 chips (Affymetrix GeneChips) were used in this study.
In vivo studies. Animal care, injection of cancer cells, and tumor measurement were described in detail in our previously published paper (25). IKI-1 (suspended in methocel/Tween 20) was given daily for 5 d/wk for a total of 2 wk, and TNF (prepared in PBS) was given twice a week for 2 wk. The control vehicles were given on the same regimen as the drugs. Control groups were 10 mice per vehicle, whereas the drug groups were 10 mice per drug.
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Results
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IKI-1 inhibited TNF-mediated phosphorylation and degradation of IB in BxPC3 cells. IKI-1 is a potent IKK inhibitor, which inhibited equally the activity of both IKK (IC50 = 80 nmol/L) and IKKβ (IC50 = 70 nmol/L)1 TNF treatment resulted in IB phosphorylation and degradation in BxPC3 pancreatic cells, which occurred within 5 min (Fig. 1
). IKI-1 effectively blocked the phosphorylation and degradation of IB in a dose-dependent manner.
IKI-1 inhibited TNF-induced p65 translocation. Activation of IKK triggers the translocation of NF-B to the nucleus. The effect of IKI-1 on p65 nuclear translocation was examined with the use of ArrayScan VTI HCS Reader (Thermo Fisher Scientific). In the absence of TNF, p65 was primarily located in the cytoplasm (Fig. 2A
). Upon TNF treatment, nearly all p65 signals were detected in the nucleus (Fig. 2A). IKI-1 inhibited p65 nuclear translocation in a dose-dependent manner with an IC50 of 
200 nmol/L (200 ± 15, n = 8). To confirm the data generated by ArrayScan, we performed standard immunofluorescence staining of p65. The results were similar and supportive of the conclusion based on ArrayScan analysis (Fig. 2B). To rule out the possibility that IKI-1 is a nonselective inhibitor of transcription factors, we tested its effect on Stat3 translocation induced by TNF. We found no significant inhibition of Stat3 translocation using up to 10 µmol/L of IKI-1 (data not shown).
IKI-1 inhibited TNF-induced gene expression in BxPC3. Because NF-B controls many genes, we used oligonucleotide array to study the effect of IKI-1 on genes regulated by TNF. Genes, whose expression was induced by TNF treatment from 1.5-fold to 21-fold (P 
0.01), were selected for further analysis. TNF alone induced 236 nonredundant genes (Supplementary Table S2). Cotreatment with IKI-1 (1 µmol/L) inhibited most of the TNF-induced genes (Fig. 3A
). Among all the genes, 102 genes were inhibited by >70%, 80 genes were inhibited from 30% to 70%, and the remaining 54 genes were inhibited by <30% (Fig. 3B). Examples of NF-B–regulated genes are illustrated in Fig. 3C, confirming that increase in cell death by TNF and IKI-1 was due to the inhibition of key molecules involved in cell survival. A complete list of TNF-induced genes with and without IKI-1 is submitted as Supplementary Data.
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Figure 3. Inhibition of NF-B target genes by IKI-1. BxPC3 cells were treated with vehicle, IKI-1 (1 µmol/L), TNF 5 ng/mL, or combination of IKI-1 and TNF. Cells were harvested, and genes were profiled according to what was described in Materials and Methods. Genes that were induced by TNF with signals of >30-fold and 1.5-fold over the vehicle control (P < 0.01) were selected. A, effect of IKI-1, TNF, and combination of both on the expression of genes. B, effect of IKI-1 on TNF-induced genes. C, representative NF-B target genes inhibited by IKI-1. Columns, means of three experiments carried out in triplicate; bars, SE.
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IKI-1 enhanced TNF-mediated growth inhibition of BxPC3 cells. Inhibition of NF-B pathway was shown to enhance TNF apoptotic effect in multiple cell lines. The combination effect on the growth of BxPC3 pancreatic cancer cells was thus tested. Figure 4A
shows that IKI-1 itself had moderate effect on the growth of BxPC3 cells. However, in the presence of a non–growth inhibitory dose of TNF (5 ng/mL), the IC50 of IKI-1 decreased 5-fold. To confirm that this combination effect was mediated through the inhibition of IKKβ in BxPC3 cells, we treated cells with siRNA of IKK and IKKβ in the presence or absence of TNF. Synergistic effect was seen from cells treated with siRNA of IKKβ, but not IKK, or nontarget siRNA control (Fig. 4B and C).
IKI-1 enhanced TNF-mediated apoptosis. To understand the mechanisms by which IKI-1 enhanced TNF-mediated growth inhibition, we sought to study the combination effect on caspase activity. Whereas either TNF or IKI-1 alone had little effect on the activity of caspase-3 and caspase-7, together, they dramatically increased the activity of caspase-3 and caspase-7. Additionally, IKI-1 dramatically increased TNF-mediated apoptosis measured by DNA fragmentation (Fig. 5B
). This effect is primarily due to the activation of caspases, because cells treated with a pan caspase inhibitor (ZVAD-FMK) showed much reduced apoptosis induced by the combination (Fig. 5B).
IKI-1 potentiated TNF-induced apoptosis in BxPC3 xenograft model. The combination effect observed in vitro prompted us to study the efficacy of this combination in BxPC3 mouse xenograft model. IKI-1 was given 100 mg/kg p.o. twice daily for 5 days a week for a total of 2 weeks. TNF (1 µg/tumor) was injected intratumorally twice a week. Whereas neither IKI-1 nor TNF had any effect on tumor growth, the combination of both resulted in significant inhibition of tumor growth compared with the control (Fig. 6
).
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Discussion
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In this study, we show that IKI-1, a potent IKK inhibitor, effectively inhibited the TNF-induced phosphorylation of IB and nuclear translocation of p65 in BxPC3 pancreatic cancer cells. We further investigated the effect of IKI-1 on TNF-mediated biological responses, such as NF-B target genes regulation, apoptosis, growth inhibition, and tumor growth. Our results show that IKI-1 dramatically potentiated the effect of TNF on the growth of pancreatic cancer cells through the activation of apoptotic pathway. Similar effect was also observed in another pancreatic cancer line, Panc-1 cells (Supplementary Fig. S1) and multiple nonpancreatic lines (Supplementary Table S1), suggesting that the potentiation in growth inhibition is mechanism-based rather than a cell line phenomena. Using RNA interference to knockdown IKKβ and gene profiling approaches, we determined that the potentiation correlated with the inhibition of IKKβ and, consequently, NF-B–mediated target genes. Our study shows that combination of TNF and IKK inhibitor may have a potential to treat pancreatic cancer patients whose tumors are irresectable.
Earlier studies using cells from either NF-B knockout mice or cells transfected with an IB superrepressor revealed that NF-B plays an important role in the resistance to TNF-mediated cell death (14–16). This is because NF-B regulates multiple survival genes to protect cells from cell death. Therefore, when NF-B activity is blocked, the TNF prodeath effect is potentiated tremendously. Multiple studies using NF-B inhibitors have resulted in similar results (17–22). However, these NF-B inhibitors usually have multiple activities, which obscure the interpretation of the results. Recently, Frelin and colleagues showed that an IKKβ inhibitor AS602868 potentiated the effect of TNF in Jurkat leukemic cells (23). It remains unclear if this potentiation is specific to AS602868 or the mechanism of inhibiting IKK/NF-B pathway. To address this question, we used siRNA of IKK and IKKβ to show that, indeed, the effect of TNF can be potentiated in the IKKβ, but not IKK, knockdown pancreatic cells. Similar augmentation was obtained with our small molecule inhibitor IKI-1 (Fig. 4A). The knockdown study results seemed to suggest that IKKβ is responsible for the survival of cells under TNF treatment. Studies with a selective IKKβ inhibitor IV and our own selective inhibitors also supported this notion (data not shown).
Using caspase and DNA fragmentation assays, we showed that the synergistic inhibition of cellular growth with the combination of TNF and IKI-1 was largely due to increased apoptosis (Fig. 5A and B). In the latter assay, a pan caspase inhibitor abrogated majority of the caspase activity. These results are in agreement with Frelin's finding in Jukat cells (23). The dramatic increase in apoptosis also explains the initial shrinkage of tumor in a pancreatic tumor xenograft model when both TNF and IKI-1 were given (Fig. 6).
Pancreatic cancer is presently the fourth leading cause of cancer death in Western countries, with the poorest survival rate among all cancers (2008 Cancer Facts). The high fatality rate is due to undetectable progression of the disease until late stages, the lack of specific and sensitive markers for early detection and the largely refractory response to available surgical, chemotherapeutic, and radiotherapeutic treatment modalities (26–30). In 45% of patients with pancreatic cancer, the primary tumor has already metastasized by the time of diagnosis to distal sites, including the liver, lungs, duodenum, and peritoneum, whereas an additional 35% to 45% of patients suffer from irresectable or locally advanced disease.
The current treatment is inadequate, given the prevalence of the disease. TNF is not a feasible anticancer agent for pancreatic cancer due to its systemic toxicities. To overcome systemic toxicities, many innovative approaches have been tried. Targeted delivery using vasculature-specific binding peptide (31), receptor-selective TNF mutant to reduce toxic effect (32), liposomal delivery, and viral delivery of TNF have been explored but fall short of being effective enough to treat patients. A promising intratumoral delivery of radiation-induced activation of viral vector expressing TNF gene is currently in clinical trials for several cancer types, including pancreatic cancer (33, 34). Initial results showed reduced systemic toxicities and safety. Recently, colloidal gold nanoparticles coupled with TNF also showed promising results by enhancing the level of TNF in tumors from 7-fold to 10-fold without causing significant systemic toxicities (35). Our data, along with those of others', strongly suggest that the combination of an IKK inhibitor with TNF provides an effective treatment option for pancreatic cancer patients through the use of reduced dose of TNF.
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Disclosure of Potential Conflicts of Interest
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All of the authors have an ownership interest in Wyeth.
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Acknowledgments
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The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked advertisement in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
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Footnotes
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Note: Supplementary data for this article are available at Cancer Research Online (http://cancerres.aacrjournals.org/).
Current address for Y. Zhang: Enzon Pharmaceutical, 20 Kingsbridge Road, Piscataway, NJ 08854.
1 S. Sum, L. Chen, D. Powell, T. Mansour, Y. Zhang, M. Gavriil, T. Saddler. N-[3-(dimethylamino)propyl]-4-{[4-(3-fluoro-4-methoxyphenyl)pyrimidin-2-yl]amino}benzenesulfonamide: an orally available IKK inhibitor with antitumor activity, manuscript in preparation. 
Received 4/24/08.
Revised 8/19/08.
Accepted 8/25/08.
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References
|
|---|
- Bazzoni F, Beutler B. The tumor necrosis factor ligand and receptor families. N Engl J Med 1996;334:1717–25.[Free Full Text]
- Pfeffer K. Biological functions of tumor necrosis factor cytokines and their receptors. Cytokine Growth Factor Rev 2003;14:185–91.
- Tracey D, Klareskog L, Sasso EH, Salfeld JG, Tak PP. Tumor necrosis factor antagonist mechanisms of action: a comprehensive review. Pharmacol Ther 2008;117:244–79.[CrossRef][Medline]
- Lejeune FJ, Ruegg C, Lienard D. Clinical applications of TNF- in cancer. Curr Opin Immunol 1998;10:573–80.[CrossRef][Medline]
- Mocellin S, Rossi CR, Pilati P, Nitti D. Tumor necrosis factor, cancer and anticancer therapy. Cytokine Growth Factor Rev 2005;16:35–53.[CrossRef][Medline]
- Mocellin S, Pilati P, Nitti D. Towards the development of tumor necrosis factor (TNF) sensitizers: making TNF work against cancer. Curr Pharm Des 2007;13:537–51.[CrossRef][Medline]
- Tracey K. The acute and chronic pathophysiologic Effects. In: Beutler B, editor. Tumor necrosis factors: the molecules and their emerging role in medicine. New York: Raven Press; 1992. p. 255–73.
- Malik S. The activity of TNF in experimental cancer models. In: Beutler B, editor. Tumor necrosis factors: the molecules and their emerging role in medicine. New York: Raven Press; 1992. p. 407–23.
- MacEwan DJ. TNF ligands and receptors — a matter of life and death. Br J Pharmacol 2002;135:855–75.[CrossRef][Medline]
- Wajant H, Pfizenmaier K, Scheurich P. Tumor necrosis factor signaling. Cell Death Differ 2003;10:45–65.[CrossRef][Medline]
- Karin M, Ben-Neriah Y. Phosphorylation meets ubiquitination: the control of NF-B activity. Annu Rev Immunol 2000;18:621–63.[CrossRef][Medline]
- Perkins ND. Integrating cell-signalling pathways with NF-B and IKK function. Nat Rev Mol Cell Biol 2007;8:49–62.[CrossRef][Medline]
- Scheidereit C. IB kinase complexes: gateways to NF-B activation and transcription. Oncogene 2006;25:6685–705.
- Beg AA, Baltimore D. An essential role for NF-B in preventing TNF--induced cell death. Science 1996;274:782–4.[Abstract/Free Full Text]
- Van Antwerp DJ, Martin SJ, Kafri T, Green DR, Verma IM. Suppression of TNF--induced apoptosis by NF-B. Science 1996;274:787–9.[Abstract/Free Full Text]
- Wang CY, Mayo MW, Baldwin AS, Jr. TNF- and cancer therapy-induced apoptosis: potentiation by inhibition of NF-B. Science 1996;274:784–7.[Abstract/Free Full Text]
- Li YQ, Zhang ZX, Xu YJ, et al. N-Acetyl-L-cysteine and pyrrolidine dithiocarbamate inhibited nuclear factor-B activation in alveolar macrophages by different mechanisms. Acta Pharmacol Sin 2006;27:339–46.[CrossRef][Medline]
- McDade TP, Perugini RA, Vittimberga FJ, Jr., Carrigan RC, Callery MP. Salicylates inhibit NF-B activation and enhance TNF--induced apoptosis in human pancreatic cancer cells. J Surg Res 1999;83:56–61.[CrossRef][Medline]
- Oka S, Kamata H, Kamata K, Yagisawa H, Hirata H. N-acetylcysteine suppresses TNF-induced NF- B activation through inhibition of IB kinases. FEBS Lett 2000;472:196–202.[CrossRef][Medline]
- Sarkar A, Sreenivasan Y, Ramesh GT, Manna SK. β-D-Glucoside suppresses tumor necrosis factor-induced activation of nuclear transcription factor B but potentiates apoptosis. J Biol Chem 2004;279:33768–81.[Abstract/Free Full Text]
- Sethi G, Ahn KS, Pandey MK, Aggarwal BB. Celastrol, a novel triterpene, potentiates TNF-induced apoptosis and suppresses invasion of tumor cells by inhibiting NF-B-regulated gene products and TAK1-mediated NF-B activation. Blood 2007;109:2727–35.[Abstract/Free Full Text]
- Zhang SY, Lin ZN, Yang CF, Shi XL, Ong CN, Shen HM. Suppressed NF- B and sustained JNK activation contribute to the sensitization effect of parthenolide to TNF--induced apoptosis in human cancer cells. Carcinogenesis 2004;25:2191–9.[Abstract/Free Full Text]
- Frelin C, Imbert V, Griessinger E, Loubat A, Dreano M, Peyron JF. AS602868, a pharmacological inhibitor of IKK2, reveals the apoptotic potential of TNF- in Jurkat leukemic cells. Oncogene 2003;22:8187–94.[CrossRef][Medline]
- Velasco AM, Gillis KA, Li Y, et al. Identification and validation of novel androgen-regulated genes in prostate cancer. Endocrinology 2004;145:3913–24.
- Sadler TM, Gavriil M, Annable T, Frost P, Greenberger LM, Zhang Y. Combination therapy for treating breast cancer using antiestrogen, ERA-923, and the mammalian target of rapamycin inhibitor, temsirolimus. Endocr Relat Cancer 2006;13:863–73.[Abstract/Free Full Text]
- Tse RV, Dawson LA, Wei A, Moore M. Neoadjuvant treatment for pancreatic cancer — a review. Crit Rev Oncol Hematol 2008;65:263–74.[CrossRef][Medline]
- Welsch T, Kleeff J, Friess H. Molecular pathogenesis of pancreatic cancer: advances and challenges. Curr Mol Med 2007;7:504–21.[CrossRef][Medline]
- Wolff RA. Chemotherapy for pancreatic cancer: from metastatic disease to adjuvant therapy. Cancer J 2007;13:175–84.[CrossRef][Medline]
- Hines OJ, Reber HA. Pancreatic neoplasms. Curr Opin Gastroenterol 2004;20:452–8.[CrossRef][Medline]
- Fernandez-Zapico ME, Kaczynski JA, Urrutia R. Pancreatic cancer research: challenges, opportunities, and recent developments. Curr Opin Gastroenterol 2002;18:563–7.[CrossRef][Medline]
- van Laarhoven HW, Gambarota G, Heerschap A, et al. Effects of the tumor vasculature targeting agent NGR-TNF on the tumor microenvironment in murine lymphomas. Invest New Drugs 2006;24:27–36.[CrossRef][Medline]
- Van Ostade X, Vandenabeele P, Everaerdt B, et al. Human TNF mutants with selective activity on the p55 receptor. Nature 1993;361:266–9.[CrossRef][Medline]
- Chang KJ, Lee JG, Holcombe RF, Kuo J, Muthusamy R, Wu ML. Endoscopic ultrasound delivery of an antitumor agent to treat a case of pancreatic cancer. Nat Clin Pract Gastroenterol Hepatol 2008;5:107–11.[CrossRef][Medline]
- Chang KJ, Shen SY, Gu M, et al. Effect of TNFerade local gene therapy on expression of tumor necrosis factor (TNF-) and survivin in tumors of patients with pancreatic cancer: can we prove and predict response to therapy? Gastroenterology 2004;126:A623.
- Paciotti GF, Kingston DGI, Tamarkin L. Colloidal gold nanoparticles: a novel nanoparticle platform for developing multifunctional tumor-targeted drug delivery vectors. Drug Dev Res 2006;67:47–54.[CrossRef]
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Abstract
Introduction
